中村 順一

Introduction: Failed spinal fusion surgery sometimes requires salvage surgery when symptomatic, especially with postsurgical decrease in intervertebral disc height followed by foraminal stenosis. For such cases, an anterior approach to lumbar lateral interbody fusion (LLIF) provides safe, direct access to the pathological disc space and a potential improvement in the fusion rate. One LLIF approach, oblique lateral interbody fusion (OLIF), targets the oblique lateral window of the intervertebral discs to achieve successful lateral interbody fusion. The current technical note describes spinal revision surgery using the OLIF procedure. Technical Note: The subjects were patients with leg pain and/or lower back pain derived from decreased intervertebral height followed by foraminal stenosis due to failed spinal fusion surgery. These patients underwent additional OLIF surgery and posterior fusion with no additional posterior direct decompression. Their outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scores at baseline and final follow-up. Bony union was also evaluated using computed tomography images at final follow-up. Six subjects were evaluated, with two representative cases described in detail. Four patients had an adjacent segment disorder, and the other two patients had pseudarthrosis due to postoperative infection. The mean JOA score improved from 5.7 ± 5.4 to 21.2 ± 2.3, with a mean recovery rate of 65.0%. All cases showed intervertebral bony union. Conclusions: We introduced a salvage strategy for failed posterior spine fusion surgery cases using the OLIF procedure. Patients effectively achieved recovered intervertebral and foraminal height with no additional posterior direct decompression.

Introduction: Osteoporosis and sarcopenia are said to be similar disorders. However, few reports have described the effects of anti-osteoporosis drugs on muscle mass in clinical practice. Methods: We selected 150 postmenopausal women with osteoporosis treated by minodronate (osteoporosis medication [OM] group) and 50 postmenopausal women without osteoporosis who did not receive treatment (no osteoporosis [NO] group). The OM group was further divided into two treatment subgroups: a combination of monthly minodronate and daily activated vitamin D vs. monthly minodronate alone. We measured lumbar spine and femoral neck bone mineral density (BMD) with dual-energy X-ray absorptiometry and muscle mass of the upper limbs, lower limbs, and trunk with bioelectrical impedance analysis at baseline and after 6 months. Results: The OM and NO groups contained 130 and 37 patients, respectively (mean age: 73.9 ± 8.3 and 74.1 ± 10.0 years, respectively). In the OM group, lumbar spine BMD significantly increased after 6 months, while lower limb muscle mass significantly decreased. In the NO group, lumbar spine BMD and lower limb muscle mass did not significantly change after 6 months. In the OM group, BMD of the lumbar spine significantly increased but the lower limb muscle mass significantly decreased after 6 months relative to the NO group. In the combination therapy subgroup of the OM group muscle mass decreased significantly less than in the minodronate-alone subgroup. Conclusions: In postmenopausal women with osteoporosis, minodronate can increase BMD but cannot increase muscle mass. However, simultaneous use of activated vitamin D can suppress muscle mass decrease. The combination of activated vitamin D and minodronate may be useful for treating osteoporosis in postmenopausal women.

Introduction: Osteoporosis can produce a persistent state of pain known as osteoporotic pain. One proposed mechanism of this pathology is increased calcitonin gene-related peptide (CGRP; a marker related to inflammatory pain) expression in the dorsal root ganglia (DRG) innervating osteoporotic vertebrae. Alternatively, a previous study revealed that axial loading caused osteoporotic pain in a rodent model of coccygeal vertebrae compression. Because this compression model is associated with trauma, additional mechanistic studies of osteoporotic pain in the absence of trauma are required. The current study aimedto evaluate the expression and relative distribution of transient receptor potential vanilloid 4 (TRPV4), a pain-related mechanoreceptor, in ovariectomized (OVX) osteoporotic rats. Methods: CGRP-immunoreactive (-ir) and TRPV4-ir DRG neurons innervating the L3 vertebrae of Sprague-Dawley rats were labeled with a neurotracer, FluoroGold. Intravertebral pH was also measured during the neurotracer procedure. TRPV4-ir/CGRP-ir FluoroGold-positive DRG neurons were quantified in sham control and OVX rats (n = 10, ea). The threshold for statistical significance was set at P < 0.05. Results: There was no statistical difference in the number of FluoroGold-positive DRG neurons between groups; however, there were significantly more CGRP-ir/TRPV4-ir FluoroGold-positive DRG neurons in the OVX group compared with the sham control group (P < 0.05) as well as the significantly increased molecular production of each peptide. Intravertebral pH was also lower in the OVX group compared with the sham control group (P < 0.05). Conclusion: Sensory neurons innervating osteoporotic vertebrae exhibited increased expression of co-localized CGRP and TRPV4 in OVX osteoporotic rats. Additionally, intravertebral pH was low in the vicinity osteoporotic vertebrae. Considering that TRPV4 is a mechanosensitive nociceptor that is activated in acidic environments, its upregulation may be associated with the pathology of osteoporotic pain derived from microinflammation involved in osteoporosis.

BACKGROUND: Finite element analysis (FEA) of the proximal femur has been previously validated with large mesh size, but these were insufficient to simulate the model with small implants in recent studies. This study aimed to validate the proximal femoral computed tomography (CT)-based specimen-specific FEA model with smaller mesh size using fresh frozen cadavers. METHODS: Twenty proximal femora from 10 cadavers (mean age, 87.1 years) were examined. CT was performed on all specimens with a calibration phantom. Nonlinear FEA prediction with stance configuration was performed using Mechanical Finder (mesh,1.5 mm tetrahedral elements; shell thickness, 0.2 mm; Poisson's coefficient, 0.3), in comparison with mechanical testing. Force was applied at a fixed vertical displacement rate, and the magnitude of the applied load and displacement were continuously recorded. The fracture load and stiffness were calculated from force-displacement curve, and the correlation between mechanical testing and FEA prediction was examined. RESULTS: A pilot study with one femur revealed that the equations proposed by Keller for vertebra were the most reproducible for calculating Young's modulus and the yield stress of elements of the proximal femur. There was a good linear correlation between fracture loads of mechanical testing and FEA prediction (R2 = 0.6187) and between the stiffness of mechanical testing and FEA prediction (R2 = 0.5499). There was a good linear correlation between fracture load and stiffness (R2 = 0.6345) in mechanical testing and an excellent correlation between these (R2 = 0.9240) in FEA prediction. CONCLUSIONS: CT-based specimen-specific FEA model of the proximal femur with small element size was validated using fresh frozen cadavers. The equations proposed by Keller for vertebra were found to be the most reproducible for the proximal femur in elderly people.

PURPOSE: The purpose of this study was to clarify the difference in implant alignment between the direct anterior approach (DAA) and the anterolateral approach in the supine position (ALS). METHODS: A retrospective comparative study consisted of 215 consecutive primary total hip arthroplasties using tapered polished and straight cemented-stems via two different minimally invasive approaches (DAA group in 106 hips and ALS group in 109 hips). RESULTS: The cup radiographic anteversion angle was significantly lower in the ALS group than in the DAA group (12.9° versus 16.9°, p = 0.001). The frequency of the safe zone tended to be more favourable in the ALS group than in the DAA group (95% versus 87%, p = 0.052). Stem alignment in the sagittal plane was significantly better in the ALS group than in the DAA group (84% versus 71%, p = 0.022). CONCLUSIONS: Both cup and stem alignments were better in the ALS group than the DAA group.

BACKGROUND: The aim was to clarify the normal fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves at the level of the hip joint and to visualize the neural tracts with diffusion tensor imaging (DTI). METHODS: Twenty-four healthy volunteers (12 men and 12 women, age 20-29 years) underwent DTI for visualization with tractography and quantification of FA and ADC values on a 3 Tesla MRI (b value = 800 s/mm2, motion probing gradient, 11 directions, time to repeat/echo time = 9000/72.6 ms, axial slice orientation, slice thickness = 3.0 mm with no inter-slice gap, field of view = 320 × 320 mm, 96 × 192 matrix, 75 slices, number of acquisitions = 4). Regions of interest in the sciatic nerve were defined at the femoral head, the S1 root, and the midpoint levels. The femoral nerve was evaluated at 3-4 cm proximal to the femoral head level. RESULTS: The tractography of the sciatic and femoral nerves were visualized in all participants. The mean FA values of the sciatic nerve were increased distally from the S1 root level, through the midpoint, and to the femoral head level (0.314, 0.446, 0.567, p = 0.001, respectively). The mean FA values of the femoral nerve were 0.565. The mean ADC values of the sciatic nerves were significantly lower in the S1 root level than in the midpoint and the femoral head level (1.481, 1.602, 1.591 × 10-3 × 10-3 mm2/s, p = 0.001, respectively). The ADC values of the femoral nerve were 1.439 × 10-3 mm2/s. FA and ADC values showed moderate to substantial inter- and intra-observer reliability without significant differences in gender or laterality. CONCLUSION: Visualization and quantification of the sciatic and femoral nerves simultaneously around the hip joint were achieved in healthy young volunteers with DTI. Clinical application of DTI is expected to contribute to hip pain research.

Idiopathic osteonecrosis of the femoral head (IONFH) is an ischemic disorder that causes bone necrosis of the femoral head, resulting in hip joint dysfunction. IONFH is a polygenic disease and steroid and alcohol have already known to increase its risk; however, the mechanism of IONFH remains to be elucidated. We performed a genome-wide association study using ~60,000 subjects and found two novel loci on chromosome 20q12 and 12q24. Big data analyses identified LINC01370 as a candidate susceptibility gene in the 20q12 locus. Stratified analysis by IONFH risk factors suggested that the 12q24 locus was associated with IONFH through drinking capacity. Our findings would shed new light on pathophysiology of IONFH.

BACKGROUND: Bone deficiency in revision total hip arthroplasty is a surgical challenge. The Murata-Chiba cup supporter (MC support ring) is an acetabular component supporter for a cementless porous-coated cup. The purpose of this study is to examine the clinical and radiographic outcomes of reconstruction of acetabular bone deficiency using iliac autografts supported by an MC support ring in a revision setting with minimum 15-year follow-up. METHODS: Fifty-nine consecutive revision total hip arthroplasties (57 patients) using the MC support ring were followed for a minimum of 15 years. Nine hips had American Academy of Orthopaedic Surgeons type II deficiency and 24 had type III defects of the acetabulum. Clinical outcomes were evaluated using the Harris hip score. Radiographic evaluation included assessment for loosening and bone graft incorporation. Kaplan-Meier survival analysis was performed. RESULTS: At a minimum 15-year follow-up (mean, 17.6 years), 32 patients (33 hips) were alive, 17 patients (18 hips) were deceased, and 8 patients (8 hips) were lost to follow-up. The mean Harris hip score improved from 44.3 to 77.2 at final follow-up. Four hips required reoperation due to deep infection (2 hips) and liner dissociation (2 hips), but no acetabular components were revised for aseptic loosening. Incorporation of the bone graft occurred in all cases. One unrevised patient had radiographic failure. Survivorship at 15 years with re-revision or radiographic failure as the end point was 90.6% (95% confidence interval, 83.0%-98.8%). CONCLUSION: The reconstruction of acetabular bone deficiency using autografts supported by an MC support ring provided satisfactory clinical and radiological results at 17.6 years postoperatively.

type:text [要旨] 【症例】75歳女性。乳癌の診断にて12年前に右乳房部分切除，腋下リンパ節郭清を施行された。術後11年で腰背部痛を自覚，画像所見および骨生検，およびPET検査の結果から乳癌第12胸椎（T12）転移性脊椎腫瘍と診断され当科における手術の方針となった。画像検査上はT12に限局した腫瘍性病変を認め，一部硬膜管に突出し硬膜管を圧排していたが膀胱直腸障害を含む神経学的臨床所見はなくADLは自立，徳橋スコアにて14点（予想予後1年以上）であったため根治目的にT12TES（total en bloc spondylectomy）を施行した。後方アプローチにてT12の上下2椎体（両側Th10，11，L1，2）にペディクルスクリュー（PS）を設置，罹患T12椎体はen blocに摘出しエクスパンダブルケージを設置，T9のフックを追加してロッド固定し終刀とした。術後は疼痛・神経症状なく経過していたが，術後2週間後から座位保持時の腰背部痛が出現した。単純X線にて下位PSのルースニング，およびL1 終板の破綻とケージの同終板へのsubsidenceを認め，胸腰椎の後弯角は術後と比し15°増加していた。今後のケージ転位の進行とこれに伴う後弯増強，脊髄障害の発生の可能性を鑑み，前後合併での追加固定を行った。まず前方L1/2OLIF（oblique lateral interbody fusion）による椎体間固定を行い，前方支柱を補強後，後方アプローチにてL3，4，5，S1にPSを追加設置，さらにS2 ara-iliacスクリューを挿入した。L2PSはルースニングに伴い椎弓根内側を穿破，固定性が破綻したため抜去としアンカーとしてL2/3 median hookを装着しロッド固定，終刀とした。術後の後弯角は8°に改善。スクリューのルースニングは認めず腰痛も改善したため退院，術後1年6ヶ月の段階での局所最終後弯角は18°にて症状・再発なく経過観察中である。 【考察】本症例におけるImplant failureの原因として，第一にT12椎体摘出後の同部での力学的脆弱性が考えられる。2-above 2-belowの固定範囲は不十分であった可能性があり術前の検討が重要であった。また，エクスパンダブルケージ使用の際に後方PSのコンプレッションも併用したが，これら二つの力のベクトル総和が過多となることで尾側終板の損傷やケージのsubsidenceにつながった可能性があり，今後はこれらのバイオメカニクス的な影響も考慮した上で術式の検討・実施を行う必要がある [SUMMARY] A 75 year-old woman was referred to our clinic for a solitary vertebral metastasis of breast cancer at the T12 level for surgical resection. The primary operation, involving total en bloc spondylectomy（TES） of the T12 vertebral body, was performed using an anterior expandable cage followed by 2-above-2-below posterior fixation. Three weeks after primary TES, she had progressive junctional kyphosis at the site of TES. The anterior expandable cage caused adjacent vertebral fracture with marked subsidence and loosening of the caudal pedicle screw（PS）. We performed revision enforcement surgery: In the prone position, the failed PS were removed, and then additional posterior fixation was performed at the L3-4-5-S1 followed by S2 alar-iliac screw fixation, and then in the right decubitus position, a lateral interbody fusion cage was inserted at the L1-2 level in the oblique lateral approach to gain more direct support. The patient returned to her activities of daily living with maintained alignment and without implant failure, and acceptable bony fusion was achieved 1.5 years postoperatively. In conclusion, excess expansion with expandable cages can be harmful when combined with the posterior compressive fixation, and long fusion should be considered in osteoporotic patients with complete vertebral resection.

STUDY DESIGN: An experimental animal study. PURPOSE: To evaluate effects of anti-vascular endothelial growth factor (VEGF) on the content and distribution of the calcitonin gene-related peptide (CGRP) in the dorsal ganglia in a rat model. OVERVIEW OF LITERATURE: Increased expression of VEGF in degenerative disc disease increases the levels of inflammatory cytokines and nerve ingrowth into the damaged discs. In animal models, increased levels of VEGF can persist for up to 2 weeks after an injury. METHODS: Through abdominal surgery, the dorsal root ganglia (DRG) innervating L5/L6 intervertebral disc were labeled (FluoroGold neurotracer) in 24, 8-week old Sprague Dawley rats. The rats were randomly allocated to three groups of eight rats each. The anti-VEGF group underwent L5/6 intervertebral disc puncture using a 26-gauge needle, intradiscal injection of 33.3 µg of the pegaptanib sodium, a VEGF165 aptamer. The control-puncture group underwent disc puncture and intradiscal injection of 10 µL saline solution, and the sham-surgery group underwent labeling but no disc puncture. Two rats in each group were sacrificed on postoperative days 1, 7, 14, and 28 after surgery. L1-L6 DRGs were harvested, sectioned, and immunostained to detect the content and distribution of CGRP. RESULTS: Compared with the control, the percentage of CGRP-positive cells was lower in the anti-VEGF group (p<0.05; 40.6% and 58.1% on postoperative day 1, 44.3% and 55.4% on day 7, and 42.4% and 59.3% on day 14). The percentage was higher in the control group compared with that of the sham group (p<0.05; sham group, 34.1%, 40.7%, and 33.7% on postoperative days 1, 7, and 14, respectively). CONCLUSIONS: Decreasing CGRP-positive cells using anti-VEGF therapy provides fundamental evidence for a possible therapeutic role of anti-VEGF in patients with discogenic lower back pain.

The principal aim of this study was to clarify the time course of pain-related behavior and pain-related sensory innervation in a rat model of hip osteoarthritis (OA) induced by intra-articular injection of mono-iodoacetate (MIA). Using 6-week-old male Sprague Dawley rats, 25 μl of sterile saline of 1% Fluoro-Gold solution (FG) (control group; n = 30) and 25 μl of sterile saline of 1% FG with 2 mg of MIA (MIA group; n = 30) was injected into the right hip joints. Gait function was evaluated using a CatWalk system after 7, 14, 28, 42, and 56 days (n = 5, respectively). Neurons in the dorsal root ganglion (DRG) between L1 and L5 were immunostained for calcitonin gene-related peptide (CGRP) and activating transcription factor-3 (ATF3). Gait analysis revealed the mean six parameters of hind paws at all time points were significantly lower in the MIA group (p = 0.05). The number of CGRP-immunoreactive (-IR) DRG neurons was significantly increased on days 7, 14, 28, and 42 peaking at 14 days in the MIA group. By contrast, expression of ATF3-IR in FG-labeled DRG neurons was significantly increased on days 42 and 57. The FG-labeled DRG neurons were distributed between L1 and L5, mainly at the L4 level. Pain-related behavior indicated by gait disturbance was observed in a MIA model of hip OA in rat. Early elevation of CGRP expression and late expression of ATF-3 were demonstrated in DRG neurons, possibly reflecting inflammatory pain and neuropathic pain in hip OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1424-1430, 2017.

OBJECTIVE: To determine the distribution of referred hip pain in patients with idiopathic osteonecrosis of the femoral head (ION). METHODS: We prospectively documented 119 hips in 90 patients with ION (mean age 51 years). Patients identified the location of pain originating in their hip on a drawing of the body. Osteoarthritis of the hip (OA) was used as a historical cohort. RESULTS: Referral of pain originating from the hip in patients with ION was 93% (111 hips) to the groin, 68% (81 hips) to the knee, 36% (43 hips) to the anterior thigh, 34% (40 hips) to the buttock, 18% (22 hips) to the lower leg, 9% (11 hips) to the greater trochanter, and 8% (9 hips) to the low back. About 97% (115 hips) of pain was located in the hip region (groin, buttock, and greater trochanter) and 77% (92 hips) showed referred pain (anterior thigh, knee, lower leg, and low back). Pain from ION was significantly more frequent in the knee and lower leg, but significantly less frequent in the lower back than pain from OA. CONCLUSION: We should be aware of ION masquerading as pain in the knee or anterior thigh.

INTRODUCTION: The purpose of this study was to compare the cemented bipolar hemiarthroplasty with uncemented about the change of intraoperative blood pressure and the incidence of major complications in elderly patients with femoral neck fracture. MATERIALS AND METHODS: This multiple center prospective cohort study included only patients with acute displaced femoral neck fracture (Garden stage III or IV). All patients were treated with cemented or uncemented bipolar hemiarthroplasty using modified Hardinge or Watson-Jones approach in the lateral decubitus position. Baseline data, medical history, type of anesthesia, FiO2 value, the number of vasopressor using during operation, femoral component, intraoperative blood pressure, SaO2, and major complications were evaluated. RESULTS: Of 164 patients (45 males and 119 females), 86 underwent cemented and 78 underwent uncemented bipolar hemiarthroplasty. Baseline medical histories were similar in both groups. In both the cemented and uncemented groups, intraoperative systolic blood pressure significantly decreased during cementing or rasping (106.3 and 103.6 mmHg) and after femoral component insertion (103.3 and 99.1 mmHg) compared to before rasping (120.7 and 116.4 mmHg) (p < 0.0001, respectively). Donaldson's grade seemed more favorable in uncemented group than in cemented group during cementing or rasping, during stem insertion; however, no patients experienced the lethal complication in both groups. CONCLUSIONS: Intraoperative blood pressure did not change during cemented and uncemented bipolar hemiarthrplasty for displaced femoral neck fracture. If the standard modern cement technique was performed during operation, bone cement is a safe and acceptable for elderly patients who have a lot of medical histories.

STUDY DESIGN: Retrospective case series. PURPOSE: The purpose of this study was to determine whether discontinuing teriparatide treatment and replacing it with bisphosphonate treatment maintains the volume of the fusion mass after posterolateral fusion (PLF) in women with postmenopausal osteoporosis. OVERVIEW OF LITERATURE: Clinical data support the efficacy of parathyroid hormone (PTH) for lumbar PLF. However, the use of PTH is limited to 2 years. METHODS: We treated 19 women diagnosed with osteoporosis and degenerative spondylolisthesis with teriparatide (20 µg daily subcutaneously). All patients underwent one-level instrumented PLF. Teriparatide was used during 2 months prior to surgery and more than 8 months after surgery. After discontinuing teriparatide treatment, all patients used bisphosphonate (17.5 mg risedronate weekly, oral administration). Area of the fusion mass across the transverse processes at one segment was determined on an anteroposterior radiograph at 1, 2, and 3 years after surgery. RESULTS: We followed 19 patients for 3 years. The average duration of teriparatide treatment was 11.5 months. The bone union rate was 95%. The average area of the bone fusion mass was not significantly different between the right and left sides at 1, 2, or 3 years after surgery (p>0.05). CONCLUSIONS: This study showed that replacing teriparatide treatment with bisphosphonate maintained the bone fusion mass volume after PLF in women with postmenopausal osteoporosis.

PURPOSE: Extreme lateral interbody fusion provides minimally invasive treatment of spinal deformity, but complications including nerve and psoas muscle injury have been noted. To avoid nerve injury, mini-open anterior retroperitoneal lumbar interbody fusion methods using an approach between the aorta and psoas, such as oblique lumbar interbody fusion (OLIF) have been applied. OLIF with percutaneous pedicle screws without posterior decompression can indirectly decompress the spinal canal in lumbar degenerated spondylolisthesis. In the current study, we examined the radiographic and clinical efficacy of OLIF for lumbar degenerated spondylolisthesis. METHODS: We assessed 20 patients with lumbar degenerated spondylolisthesis who underwent OLIF and percutaneous pedicle screw fixation without posterior laminectomy. MR and CT images and clinical symptoms were evaluated before and 6 months after surgery. Cross sections of the spinal canal were evaluated with MRI, and disk height, cross-sectional areas of intervertebral foramina, and degree of upper vertebral slip were evaluated with CT. Clinical symptoms including low back pain, leg pain, and lower extremity numbness were evaluated using a visual analog scale and the Oswestry Disability Index before and 6 months after surgery. RESULTS: After surgery, significant increases in axial and sagittal spinal canal diameter (12 and 32 %), spinal canal area (19 %), disk height (61 %), and intervertebral foramen areas (21 % on the right side, 39 % on the left), and significant decrease of upper vertebral slip (-9 %) were found (P < 0.05). Low back pain, leg pain, and lower extremity numbness were significantly reduced compared with before surgery (P < 0.05). CONCLUSIONS: Significant improvements in disk height and spinal canal area were found after surgery. Bulging of disks was reduced through correction, and stretching the yellow ligament may have decompressed the spinal canal. Lumbar anterolateral fusion without laminectomy may be useful for lumbar spondylolisthesis with back and leg symptoms.

BACKGROUND: Hip pain is transmitted to the dorsal horn of the spinal cord via the dorsal root ganglion (DRG), which contains two types of neurons with differential sensitivity to neurotrophic factors. If either type predominantly innervates the hip joint, it may represent a good target for hip joint pain treatment. METHODS: Inflammation was induced in the left hip joint of rats (n = 10) by using complete Freund's adjuvant. Fluoro-Gold (FG) was applied to the hip joint after 7 days, and T12-L6 DRGs were double-stained for calcitonin gene-related peptide (CGRP) and isolection-IB4 1 week later. RESULTS: FG-labeled neurons in the control group were distributed throughout the left DRG from T13 to L5, primarily in L2 to L4, and CGRP-positive neurons were significantly more frequent than IB4-binding neurons. In the inflammatory group, FG-labeled neurons were similarly distributed, primarily at L3 and L4, and CGRP-positive neurons were significantly more frequent than IB4-binding neurons. The percentage of CGRP-positive neurons was significantly greater in the inflammatory group (P < 0.05). CONCLUSIONS: Most small neurons innervating the hip joint express CGRP. Furthermore, hip joint inflammation caused an increase in CGRP-positive neurons, but not in IB4-binding neurons. Our results suggest that CGRP-expressing nerve growth factor-dependent neurons are primarily responsible for hip joint pain and may represent therapeutic targets.

STUDY DESIGN: A retrospective radiological study on vascular anatomy. OBJECTIVE: The aim of this study was to evaluate the anatomical and radiological features of lumbar segmental arteries with respect to the surgical field of the oblique lateral interbody fusion (OLIF) approach by using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: OLIF surgery restores disc height and enables indirect decompression of narrowed spinal canals through an oblique lateral approach to the spine, by using a specially designed retractor. In a minimal surgical field, injuring segmental arteries can cause massive hemorrhage. METHODS: We reviewed 272 lumbar MRIs. In the sagittal images, the intersection of one-third of the anterior and median lines of the intervertebral disc (IVD) was considered the center of the virtually installed OLIF retractor. The cephalad/caudal distances from the center and branch angles of segmental arteries to the longitudinal axes of the aorta were measured to determine whether the segmental arteries run into the surgical area. Statistical significance was set at P < 0.05. RESULTS: The branch angles of segmental arteries were significantly acute (≤90°) in L1-L3 arteries and significantly blunt (>90°) in L4 and L5 arteries. The average distance to the center of the caudal adjacent IVD was significantly larger, and there were generally low possibilities for the existence of segmental arteries below half of the vertebral height, where the surgeons can install fixation pins with ease and safety. Among the lumbar segmental arteries, L5 showed specific characteristics with significant deviation, a four times (4.1% vs. L1-L3 segmental arteries) higher adjacency rate, and a two-fifth (38.6% vs. 100%) lower existence rate. CONCLUSION: Segmental arteries can be involved in the surgical field of OLIF especially in the lower lumbar spine level of L4 and L5 arteries, which can directly run across IVDs. L5 segmental arteries can also be iliolumbar arteries that have an abnormal trajectory by nature. LEVEL OF EVIDENCE: 4.

STUDY DESIGN: Retrospective case series. PURPOSE: The purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up. OVERVIEW OF LITERATURE: Extreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported. METHODS: We evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1-2 to L5-S1 was calculated using a Picture Archiving and Communication System. RESULTS: Spinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1-2 to L5-S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4-5 (30 mm2) (fusion level) was significantly less than that at L1-2 to L3-4 or L5-S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4-5 was significantly larger than at the other levels. CONCLUSIONS: Spinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery.

BACKGROUND: The purpose of this prospective cohort study was to clarify the safety and efficacy of total hip arthroplasty via the direct anterior approach in the supine position with a novel mobile traction table. METHODS: The first experience of consecutive surgeries by a single surgeon using the direct anterior approach with a traction table is described with a two-year follow-up period. Of 121 patients, 100 patients without previous hip surgeries, severe deformity, or cemented implants were divided into two groups comprising the first 50 patients and the second 50 patients. RESULTS: The implant survival rate was 99% at the two-year follow-up. Revision surgery was required for periprosthetic femoral fracture in one patient. The complication rate possibly related to the traction table was 5% (5 patients): three anterior dislocations, one periprosthetic femoral fracture, and one intraoperative perforation caused by femoral rasping. The complication rate tended to decrease in the second group compared to the first group (4% versus 6%). Mean surgical time (72.0 minutes versus 82.5 min, p = 0.027), rate of allogeneic blood transfusion (2% versus 24%, p = 0.001), and cup alignment in the safe zone (100% versus 88%, p = 0.027) were significantly improved in the second group compared to the first group. CONCLUSION: The direct anterior approach with a novel mobile traction table showed a positive learning curve for surgical time, rate of allogeneic blood transfusion, and cup alignment in the safe zone.

STUDY DESIGN: A retrospective multicenter survey. OBJECTIVE: To investigate the perioperative complications of oblique lateral interbody fusion (OLIF) surgery. SUMMARY OF BACKGROUND DATA: OLIF has been widely performed to achieve minimally invasive, rigid lumbar lateral interbody fusion. The associated perioperative complications are not yet well described. METHODS: The participants were patients who underwent OLIF surgery under the diagnosis of degenerative lumbar diseases between April 2013 and May 2015 at 11 affiliated medical institutions. The collected data were classified into intraoperative and early-stage postoperative (≤1 mo) complications. The intraoperative complications were then subcategorized into organ damage (neural, vertebral, vascular, and others) and other complications, mainly related to instrumental failure. The collected data were also divided and analyzed based on whether the surgeon was certified to perform the surgery and the incidence of complications in the early (April 2013-March 2014) and late stages (April 2014-May 2015) of OLIF introduction. RESULTS: In the 155 included patients, 75 complications were reported (incidence rate, 48.3%). The most common complication was endplate fracture/subsidence (18.7%), followed by transient psoas weakness and thigh numbness (13.5%) and segmental artery injury (2.6%). Almost all these complications were transient, except for three patients who had permanent damage: one had ureteral injury and two had neurological injury. Postoperative complications included surgical site infection (1.9%) and reoperation (1.9%). Whether the primary operator was experienced did not affect the incidence of complications. Regarding the introductory stage, the incidence of complications was 50% in the early stage and 38% in the late stage. CONCLUSION: The overall incidence of perioperative complications of OLIF surgery reached 48.3%, of which only 1.9% resulted in permanent damage. Our analysis based on surgeon experience indicated that the OLIF procedure could be performed without increasing incidence of complications, under the guidance of experienced supervisors. LEVEL OF EVIDENCE: 3.

BACKGROUND: Elderly female patients complaints of acute low back pain (LBP) may involve vertebral fracture (VF), among which occult VF (OVF: early-stage VF without any morphological change) is often missed to be detected by primary X-ray examination. The current study aimed to investigate the prevalence of VF and OVF and the diagnostic accuracy of the initial X-ray in detecting OVF. METHOD: Subjects were elderly women (>70 years old) complaining of acute LBP with an accurate onset date. Subjects underwent lumbar X-ray, magnetic resonance imaging (MRI), and bone mineral density (BMD) measurement at their first visit. The distribution of radiological findings from X-ray and magnetic resonance imaging (MRI) as well as the calculation of the prevalence of VF and OVF are investigated. RESULTS: The prevalence of VF among elderly women with LBP was 76.5% and L1 was the most commonly injured level. Among VF cases, the prevalence of OVF was 33.3%. Furthermore, osteoporotic patients tend to show increased prevalence of VF (87.5%). The predictive values in detecting VF on the initial plain X-ray were as follows: sensitivity, 51.3%; specificity, 75.0%; and accuracy rate, 56.7%. CONCLUSIONS: Acute LBP patients may suffer vertebral injury with almost no morphologic change in X-ray, which can be detected using MRI.

Spinal metastasis of differentiated thyroid cancer can have a favorable prognosis if radical surgery is performed. We encountered a case of spinal metastasis involving three anterior vertebral bodies at the posterior element fusion level and successfully achieved adequate stability by radical surgery involving only the anterior elements. A 67-year-old woman who had numbness and muscle weakness in the lower limbs caused by metastatic spinal tumor at the posterior element fusion level of L1-L3 vertebrae was treated with radical surgery of only the anterior element to gain stability. Similar situations may occur in cases involving other malignant tumor metastases or spinal primary tumors. If such a case occurs, this method could be useful in preventing metastasis to the posterior element.

Patellar tendon rupture in children is especially rare. The fact that the area of traumatic rupture has wide variations makes surgical treatment difficult. We present an 11-year-old boy with acute traumatic patellar tendon rupture at the tibial tuberosity attachment without avulsion fracture. Primary end-to-end repair and reinforcement using 1.5 mm stainless steel wires as a surgical strategy were undertaken. Early range of motion began with a functional knee brace and the reinforced stainless wire was removed 3 months after surgery. Knee function at the final follow-up was satisfactory. We suggest that this strategy may provide a useful option for surgical treatment.

Introduction: Oblique lateral interbody fusion (OLIF) can achieve recovery of lumbar lordosis (LL) in minimally invasive manner. The current study aimed to evaluate the location of lateral intervertebral cages during OLIF in terms of LL correction. Methods: The subjects were patients who underwent OLIF for lumbar degenerative diseases, including lumbar spinal stenosis, spondylolisthesis, and discogenic low back pain. Their clinical outcome was evaluated using visual analogue scale on lower back pain (LBP), leg pain and numbness. The following parameters were retrospectively evaluated on plain radiographic images and computed tomography scans before and at 1 year after OLIF: the intervertebral height, vertebral translation, and sagittal angle. The cage position was defined by equally dividing the caudal endplate into five zones (I to V), and its association with segmental lordosis restoration was analyzed. Subjects were also evaluated for a postoperative endplate injury. Results: Eighty patients (121 fused levels) with lumbar degeneration who underwent OLIF were included. There were no significant specific distribution in preoperative disc pathology such as disc angle, height, and translation. After OLIF, sagittal alignment was improved with an average correction angle of 3.8º at the instrumented segments in a level-independent fashion. All cases showed significant improvement in clinical outcomes, and had improvement in the radiological parameters (P<0.05). A detailed analysis of the cage position showed that the most significant sagittal correction and the most postoperative endplate injuries occurred in the farthest anterior zone (I). Cages with a 12-mm height were associated with more endplate injuries compared with shorter cages (8 or 10 mm). Conclusions: OLIF improves sagittal alignment with an average correction angle of 3.8º at the instrumented segments. We suggest that the optimal cage position for better lordosis correction and the fewest endplate injuries is zone II with a cage height of up to 10 mm.

PURPOSE: We examined duloxetine's effectiveness in the treatment of neuropathic pain in patients who were intolerant to continuous pregabalin administration. MATERIALS AND METHODS: The present study is a retrospective study of patients diagnosed with neuropathic pain with neuropathic leg pain as the chief complaint. We analyzed 20 cases in which pregabalin was changed to duloxetine because of adverse effects (16 cases) or treatment failure (4 cases). The incidence of adverse events after duloxetine administration was used as the primary endpoint, with the secondary endpoint being the leg pain level based on a numerical rating scale (NRS). RESULTS: The incidence of adverse events after starting duloxetine was 40%. Average leg pain scores measured on the NRS were 8.4±1.4, 6.4±1.4, and 4.1±2.0 at the time of the patients' first visit, pregabalin discontinuation, and after switching to duloxetine, respectively. A significant difference in NRS scores was found between the first visit and pregabalin discontinuation and also between pregabalin discontinuation and after the switch to duloxetine (p<0.05), indicating that pain decreases over time. Furthermore, NRS scores significantly declined between the patients' first visit and after the switch to duloxetine (p<0.05). The improvement in NRS score was 20±12.8% after pregabalin administration and 23±12.0% after duloxetine administration compared with baseline scores (no significant difference between pregabalin and duloxetine; p>0.05). CONCLUSION: When patients with neuropathic pain are unable to tolerate pregabalin because of adverse effects, changing the medication to duloxetine may be an option.

Introduction: Osteoporosis is a pathological state with an unbalanced bone metabolism mainly caused by accelerated osteoporotic osteoclast activity due to a postmenopausal estrogen deficiency, and it causes some kinds of pain, which can be divided into two types: traumatic pain due to a fragility fracture from impaired rigidity, and pain derived from an osteoporotic pathology without evidence of fracture. We aimed to review the concepts of osteoporosis-related pain and its management. Methods: We reviewed clinical and basic articles on osteoporosis-related pain, especially with a focus on the mechanism of pain derived from an osteoporotic pathology (i.e., osteoporotic pain) and its pharmacological treatment. Results: Osteoporosis-related pain tends to be robust and acute if it is due to fracture or collapse, whereas pathology-related osteoporotic pain is vague and dull. Non-traumatic osteoporotic pain can originate from an undetectable microfracture or structural change such as muscle fatigue in kyphotic patients. Furthermore, basic studies have shown that the osteoporotic state itself is related to pain or hyperalgesia with increased pain-related neuropeptide expression or acid-sensing channels in the local tissue and nervous system. Traditional treatment for osteoporotic pain potentially prevents possible fracture-induced pain by increasing bone mineral density and affecting related mediators such as osteoclasts and osteoblasts. The most common agent for osteoporotic pain management is a bisphosphonate. Other non-osteoporotic analgesic agents such as celecoxib have also been reported to have a suppressive effect on osteoporotic pain. Conclusions: Osteoporotic pain has traumatic and non-traumatic factors. Anti-osteoporotic treatments are effective for osteoporotic pain, as they improve bone structure and the condition of the pain-related sensory nervous system. Physicians should always consider these matters when choosing a treatment strategy that would best benefit patients with osteoporotic pain.

Background and Objective Cortical bone trajectory (CBT) spondylodesis is a novel screw fixation method in which screws are inserted through the pedicle in a caudal-medial to cephalad-lateral direction, providing a similar or more rigid spinal fixation compared with traditional pedicle screws. However, the traditional CBT technique requires invasive detaching and opening of the paraspinal muscle. In a small clinical prospective study we introduced a percutaneous CBT fixation technique by modifying the percutaneous pedicle screw (PPS) technique and evaluated the short-term outcome. Materials and Methods We enrolled 40 patients with lower back pain (LBP) and limb r;adicular pain with a diagnosis of spondylolisthesis who underwent transforaminal lumbar interbody fusion surgery. The patients were divided into two groups according to screw trajectory: the percutaneous CBT (pCBT) and the traditional PPS arms (20 patients in each). A consecutive group of 20 patients underwent traditional PPS, and the other underwent pCBT; dorsal spondylodesis was combined with transforaminal lumbar interbody fusion (TLIF) in both groups. Perioperative data such as operative time, blood loss, duration of fluoroscopy, and total incision length were investigated. Postoperative outcomes were evaluated using the visual analog scale (VAS) for LBP and leg pain at baseline, 1, 6, and 12 months. A p value < 0.05 was considered statistically significant. Results We observed no significant disadvantages in pCBT patients in perioperative and postoperative data compared with the PPS group. There were no complications. The pCBT patients showed a significantly shorter total incision length (p < 0.01) with a significantly shorter duration of fluoroscopy (p < 0.05). The postoperative VAS score was significantly improved in the pCBT group, especially 6 months after the surgery (p < 0.05). Conclusion The pCBT spondylodesis provided an outcome comparable with PPS fixation with a tendency for improvement 1 year postsurgery. This technique can be used in appropriate cases, combined with lumbar interbody fusion.

In patients with lower back and leg pain, lumbar foraminal stenosis (LFS) is one of the most important pathologies, especially for predominant radicular symptoms. LFS pathology can develop as a result of progressing spinal degeneration and is characterized by exacerbation with foraminal narrowing caused by lumbar extension (Kemp's sign). However, there is a lack of critical clinical findings for LFS pathology. Therefore, patients with robust and persistent leg pain, which is exacerbated by lumbar extension, should be suspected of LFS. Radiological diagnosis is performed using multiple radiological modalities, such as magnetic resonance imaging, including plain examination and novel protocols such as diffusion tensor imaging, as well as dynamic X-ray, and computed tomography. Electrophysiological testing can also aid diagnosis. Treatment options include both conservative and surgical approaches. Conservative treatment includes medication, rehabilitation, and spinal nerve block. Surgery should be considered when the pathology is refractory to conservative treatment and requires direct decompression of the exiting nerve root, including the dorsal root ganglia. In cases with decreased intervertebral height and/or instability, fusion surgery should also be considered. Recent advancements in minimally invasive lumbar lateral interbody fusion procedures enable effective and less invasive foraminal enlargement compared with traditional fusion surgeries such as transforaminal lumbar interbody fusion. The lumbosacral junction can cause L5 radiculopathy with greater incidence than other lumbar levels as a result of anatomical and epidemiological factors, which should be better addressed when treating clinical lower back pain.

STUDY DESIGN: Retrospective case series. PURPOSE: To examine the efficacy of TachoSil for vessel injury in 6 patients who underwent anterior lumbar fusion surgery (ALF). OVERVIEW OF LITERATURE: ALF for the lumbar spine has a high rate of success, although intraoperative concerns and iatrogenic complications are known, and injury of a major vessel is sometimes a complication. The efficacy of TachoSil, a fibrin-based hemostat, has been reported for several types of surgery; however, use of TachoSil for ALF surgery has not been described. Here, we report on the efficacy of TachoSil in 6 patients, who underwent ALF after vascular surgeons having difficulty in repairing vessels. METHODS: Two man and 4 women with average age of 50.8±10.9 (mean±standard deviation) were diagnosed with a vertebral tumor (2 patients), L4 degenerative spondylolisthesis (2 patients), and L5 spondylolytic spondylolisthesis (2 patients) and underwent ALF. The blood vessels injured included the common iliac vein in 2 patients and a branch of a segmental artery from the aorta in 4 patients. We consulted a vascular surgeon to suture or repair the vessels during surgery, and although the vascular surgeon attempted to address the injuries, suturing or repair was not possible in these cases. For this reason, we used TachoSil to repair the injury in the vessels walls or to stop the bleeding. RESULTS: Time to pressure hemostasis using TachoSil was 34±12 minutes, and total blood loss was 1,488±1,711 mL. Nevertheless, all vessel injuries were controlled by the use of TachoSil. CONCLUSIONS: We recommend the use of TachoSil for vessel injuries that vascular surgeons cannot suture or repair during ALF surgery.

STUDY DESIGN: Retrospective case series. PURPOSE: To determine whether symptoms predict surgical outcomes for patients with discogenic low back pain (DLBP). OVERVIEW OF LITERATURE: Specific diagnosis of DLBP remains difficult. Worsening of pain on flexion is a reported symptom of DLBP. This study sought to determine whether symptoms predict surgical outcomes for patients with DLBP. METHODS: We investigated 127 patients with low back pain (LBP) and no dominant radicular pain. Magnetic resonance imaging was used to select patients with disc degeneration at only one level. If pain was provoked during discography, we performed fusion surgery (87 patients). Visual analogue scale score and responses to a questionnaire regarding symptoms including worsening of pain on flexion or extension were assessed. Symptom sites before surgery were categorized into LBP alone, or LBP plus referred inguinal or leg pain. We followed 77 patients (average 3.0 years) and compared symptoms before surgery with surgical outcome. RESULTS: Sixty-three patients with a good outcome showed postsurgical pain relief (≥60% pain relief) and 14 patients with a poor outcome did not (<60% pain relief). In patients with good outcomes, worsening of LBP was evident in 65% of cases on flexion and in 35% on extension. However, these findings were not significantly different from those in patients with poor outcomes. The percentage of patients with LBP alone was significantly lower and the percentage of patients with LBP plus referred inguinal or leg pain was significantly higher in the group with good surgical outcome compared with patients in the group with poor surgical outcome (p<0.05). CONCLUSIONS: Worsening of pain on extension may be a symptom of DLBP. Surgical outcomes were superior in patients with both LBP and either referred inguinal or leg pain compared with those having LBP alone.

STUDY DESIGN: Retrospective case series. PURPOSE: To classify back muscle degeneration using magnetic resonance imaging (MRI) and investigate its relationship with back pain after surgery. OVERVIEW OF LITERATURE: Back muscle injury and degeneration often occurs after posterior lumbar surgery, and the degeneration may be a cause of back pain. However, the relationship between back muscle degeneration and back pain remains controversial. METHODS: A total of 84 patients (average age, 65.1 years; 38 men, 46 women) with lumbar spinal stenosis underwent posterior decompression surgery alone. MRI (1.5 tesla) was evaluated before and more than a year after surgery in all patients. Muscle on MRI was classified into three categories: low intensity in T1-weighted imaging, high intensity in T2-weighted imaging (type 1), high intensity in both T1- and T2-weighted images (type 2), and low intensity in both T1- and T2-weighted imaging (type 3). The prevalence of the types and their relationship with back pain (determined on a visual analog scale) were evaluated. RESULTS: MRI revealed muscle degeneration in all patients after surgery (type 1, 6%; type 2, 82%; and type 3, 12%). Type 2 was significantly more frequent compared with types 1 and 3 (p<0.01). Low back pain was significantly improved after surgery (p<0.01). Low back pain was not associated with any MRI type of muscle degeneration after surgery (p>0.05). CONCLUSIONS: Various pathologies of back muscle degeneration after posterior lumbar surgery were revealed. Type 2 (fatty) change was most frequent, and other patients had type 3 (scar) or type 1 (inflammation or water-like) changes. According to the Modic classification of bone marrow changes, Modic type 1 change is associated with inflammation and back pain. However, no particular type of back muscle degeneration was correlated with back pain after surgery.

PURPOSE: The pathophysiology of discogenic low back pain is not fully understood. Tetrodotoxin-sensitive voltage-gated sodium (NaV) channels are associated with primary sensory nerve transmission, and the NaV1.7 channel has emerged as an analgesic target. Previously, we found increased NaV1.7 expression in dorsal root ganglion (DRG) neurons innervating injured discs. This study aimed to examine the effect of blocking NaV1.7 on sensory nerves after disc injury. MATERIALS AND METHODS: Rat DRG neurons innervating the L5/6 disc were labeled with Fluoro-Gold (FG) neurotracer. Twenty-four rats underwent intervertebral disc puncture (puncture group) and 12 rats underwent sham surgery (non-puncture group). The injury group was divided into a saline infusion group (puncture+saline group) and a NaV1.7 inhibition group, injected with anti-NaV1.7 antibody (puncture+anti-NaV1.7 group); n=12 per group. Seven and 14 days post-surgery, L1 to L6 DRGs were harvested and immunostained for calcitonin gene-related peptide (CGRP) (an inflammatory pain marker), and the proportion of CGRP-immunoreactive (IR) DRG neurons of all FG-positive neurons was evaluated. RESULTS: The ratio of CGRP-IR DRG neurons to total FG-labeled neurons in the puncture+saline group significantly increased at 7 and 14 days, compared with the non-puncture group, respectively (p<0.05). Application of anti-NaV1.7 into the disc significantly decreased the ratio of CGRP-IR DRG neurons to total FG-labeled neurons after disc puncture at 7 and 14 days (40% and 37%, respectively; p<0.05). CONCLUSION: NaV1.7 antibody suppressed CGRP expression in disc DRG neurons. Anti-NaV1.7 antibody is a potential therapeutic target for pain control in patients with lumbar disc degeneration.

Transforaminal lumbar interbody fusion (TLIF) is a popular posterior spinal fusion technique, but sometimes require salvage surgery when implant failure occurs, which involves possible neural damage due to postoperative adhesion. The current report deals with successful anterior transperitoneal salvage surgery for failed L5-S TLIF with less neural invasiveness.

BACKGROUND: The mechanism for hip pain has been unclear because of a lack of experimental animal models. We aimed to establish an intra-articular injection technique to the rat hip and to document the effect of intra-articular mono-iodoacetate (MIA) injection to the rat hip with radiography and histology. METHODS: Using 60 6-week-old male Sprague Dawley rats, 25 μl of sterile saline (control group; n = 30) and 25 μl of sterile saline with 2 mg of MIA (MIA group; n = 30) was injected into the right hip joints via posterior approach using a 27G needle. The animals were examined with X-ray and histology 7, 14, 28, 42, and 56 days later (MIA group [n = 6] and control group [n = 6], respectively). RESULTS: The MIA group showed progressive radiographic changes to the hip joint during the experimental period, whereas the control group maintained a normal appearance. The microanatomic appearance was consistent with X-ray images of progressive destruction in the MIA group and normal tissue in the control group. Osteoarthritic (OA) changes became apparent at 42 and 56 days in the MIA group. CONCLUSIONS: We established an intra-articular injection technique to the rat hip, creating a hip OA model in the rat by intra-articular injection of MIA.

OBJECTIVE: To examine the analgesic effect of intradiscal administration of a tumor necrosis factor-αα (TNF-α) inhibitor in patients with discogenic low back pain (LBP). DESIGN: Prospective, randomized study. SETTING: Department of Orthopaedic Surgery, Chiba (Japan) University Hospital. SUBJECTS: Seventy-seven patients diagnosed with discogenic LBP. METHODS: Discogenic LBP patients were randomly assigned to the etanercept (n = 38; bupivacaine [2 mL] with etanercept [10 mg]) or control (n = 39; bupivacaine [2 mL]) groups. Patients received a single intradiscal injection. Numerical rating scale (NRS) scores for LBP at baseline, 1 day, and 1, 2, 4, and 8 weeks after the injection were recorded. The Oswestry disability index (ODI) scores at baseline and at 4 and 8 weeks after injection were evaluated. Postinjection complications were recorded and evaluated. RESULTS: In the etanercept group, the NRS scores were significantly lower than in the control group at every time point after the injection for 8 weeks (P < 0.05). Similarly, 4 weeks after the injection, the ODI score was lower in the etanercept group than in the control group (P < 0.05). However, the ODI scores were not significantly different at 8 weeks. Complications were not observed. CONCLUSIONS: Single intradiscal administration of a TNF-α inhibitor can alleviate intractable discogenic LBP for up to 8 weeks. TNF-α may be involved in discogenic pain pathogenesis. This procedure is a novel potential treatment; longer-term effectiveness trials are required in the future.

Fracture of the femoral head and the acetabulum with traumatic dislocation of the hip is a severe injury representing various types and unfavorable outcome. We showed a 45-year-old man with Pipkin type-IV fracture and coxa valga. An immediate closed reduction was achieved followed by open reduction and internal fixation via a posterior approach 6 days later. However, dislocation occurred three times without traumatic events after three weeks. CT demonstrated no displacement of posterior fragments or implant failure. Femoral intertrochanteric varus osteotomy was performed to gain concentric stability and successfully resolved recurrent dislocation. Another 45-year-old woman with Pipkin type-IV fracture and coxa valga also underwent closed reduction initially and then continued conservative treatment. After eight weeks, when she started gait training, progressive pain became symptomatic. Persistent hip pain at weight bearing was not improved in spite of arthroscopic synovectomy and osteochondroplasty. Two years after injury, femoral intertrochanteric varus osteotomy was indicated and her refractory pain was resolved gradually. We suggest that femoral varus osteotomy should be considered for superolateral subluxation associated fracture dislocation of the hip in Pipkin type-IV and coxa valga.

BACKGROUND: The purpose of this diagnostic study was to quantify the effect of high-dose corticosteroid treatment on hip joint cartilage degeneration in patients with systemic lupus erythematosus (SLE), with and without osteonecrosis, using magnetic resonance imaging (MRI). METHODS: T2 mapping, with a 3.0 Tesla Discovery MR750 (GE Healthcare) MRI scanner, was performed in 12 volunteers without hip pathology (control group, 12 hips), in 11 patients with SLE without osteonecrosis, who were receiving corticosteroid therapy (corticosteroid-ON group, 17 hips), and in 15 patients with SLE receiving corticosteroids, who had noncollapsed and asymptomatic osteonecrosis (corticosteroid+ON group, 26 hips). The distribution of T2 values in the femoral head and acetabular cartilage were compared among the three groups. Step-wise multiple regression analysis was performed to determine the prognostic factors for T2 values indicative of femoral head cartilage degeneration. RESULTS: Mean T2 values of femoral head cartilage were significantly higher in the corticosteroid-ON (40.3 ms) and corticosteroid+ON (35.2 ms) groups than in the control group (30.1 ms, P = 0.001). T2 values of acetabular cartilage were significantly higher in the corticosteroid-ON group (41.8 ms) versus the control (33.4 ms) and the corticosteroid+ON groups (37.0 ms; P = 0.001). Low bone mineral density was a significant prognostic factor for high T2 values of cartilage at the femoral head in patients treated with corticosteroids, regardless of whether they had osteonecrosis. CONCLUSION: T2 mapping suggests that corticosteroid therapy and osteoporosis are independent risk factors for cartilage degeneration at the femoral head in patients with SLE.

BACKGROUND: Lumbar floating fusion occasionally causes postoperative adjacent segment disorder (ASD) at lumbosacral level, causing L5 spinal nerve disorder by L5-S1 foraminal stenosis. The disorder is considered to be one of the major outcomes of L5-S1 ASD, which has not been evaluated yet. The present study aimed to evaluate the incidence and risk factors of postoperative L5 spinal nerve disorder after lumbar interbody fusion extending to the L5 vertebra. METHODS: We evaluated 125 patients with a diagnosis of spondylolisthesis who underwent floating fusion surgery with transforaminal lumbar interbody fusion with average postoperative period of 25.2 months. The patients were regarded as symptomatic with postoperative L5 spinal nerve disorder such as radicular pain/numbness in the lower limbs and/or motor dysfunction. We estimated and compared the wedging angle (frontal view) and height (lateral view) of the lumbosacral junction in pre- and postoperative plain X-ray images and the foraminal ratio (ratio of the narrower foraminal diameter to the wider diameter in the craniocaudal direction) in the preoperative magnetic resonance image. Risk factors for the incidence of L5 spinal nerve disorder were explored using multivariate logistic regression. RESULTS: Eight of the 125 patients (6.4%) were categorized as symptomatic, an average of 13.3 months after surgery. The wedging angle was significantly higher, and the foraminal ratio was significantly decreased in the symptomatic group (both P < 0.05) compared to the asymptomatic group. Multivariate logistic regression analysis of possible risk factors revealed that the wedging angle, foraminal ratio, and multileveled fusion were statistically significant. CONCLUSIONS: Higher wedging angle and lower foraminal ratio in the lumbosacral junction were significantly predictive for the incidence of L5 nerve root disorder as well as multiple-leveled fusion. These findings indicate that lumbosacral fixation should be considered for patients with these risk factors even if they have few symptoms from the L5-S1 junction.

PURPOSE: Nuclear factor-κB (NF-κB), receptor activator of NF-κB (RANK), and RANK ligand (RANKL) are transcriptional regulators of inflammatory cytokines. RANKL expression in dorsal root ganglion (DRG) neurons is elevated in animal models of pain or intervertebral disc herniation. We sought to evaluate the effect of anti-RANKL antibodies on sensory nerves innervating injured intervertebral discs. METHOD: We labeled DRG neurons innervating L5-6 discs with FluoroGold (FG). The L5-6 discs of 36 rats were punctured using a 23-gage needle and 18 rats underwent sham surgery without disc puncture. The puncture group was evenly subdivided into a group in which 10 μl saline was administered to the injured disc and a group in which 10 μl of anti-RANKL antibody was administered. Seven and 14 days postsurgery, DRGs at L2 level were harvested, sectioned, and immunostained for calcitonin gene-related peptide (CGRP). The proportion of CGRP-immunoreactive (IR) DRG neurons of all FG-positive neurons was determined. Amount of tumor necrosis factor (TNF)-α and interleukin(IL)-6 was measured within the intervertebral discs in each group at 7 and 14 days after surgery using an enzyme-linked immunosorbent assay (ELISA). RESULTS: The proportion of CGRP-IR DRG neurons to total FG-labeled neurons innervating injured intervertebral discs and amount of TNF-α and IL-6 in the injured discs in the saline control group was significantly increased compared with that found in rats from the sham surgery group (P < 0.05). However, application of anti-RANKL antibody to the injured discs significantly decreased the proportion of CGRP-IR DRG neurons to total FG-labeled neurons and amount of TNF-α and IL-6 in the injured discs (P < 0.05). CONCLUSIONS: TNF-α and IL-6 in the injured discs increased and CGRP expression increased in DRG neurons innervating injured discs, and antibodies to RANKL could suppress this increased TNF-α, IL-6, and CGRP expression. RANKL may be a therapeutic target for pain control in patients with lumbar disc degeneration.

PURPOSE: Osteoarthritic (OA) pain is largely considered to be inflammatory pain. However, during the last stage of knee OA, sensory nerve fibers in the knee are shown to be significantly damaged when the subchondral bone junction is destroyed, and this can induce neuropathic pain. Several authors have reported that tumor necrosis factor-α (TNFα) in a knee joint plays a crucial role in pain modulation. The purpose of the current study was to evaluate the efficacy of etanercept, a TNFα inhibitor, for pain in knee OA. MATERIALS AND METHODS: Thirty-nine patients with knee OA and a 2-4 Kellgren-Lawrence grading were evaluated in this prospective study. Patients were divided into two groups; hyaluronic acid (HA) and etanercept injection. All patients received a single injection into the knee. Pain scores were evaluated before and 4 weeks after injection using a visual analogue scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and they were compared between the groups. RESULTS: Before injection, VAS and WOMAC scores were not significantly different between the groups (p>0.05). Significant pain relief was found in the etanercept group at 1 and 2 weeks by VAS, and at 4 weeks by WOMAC score, compared with the HA group (p<0.05). No adverse events were observed in either group. CONCLUSION: Direct injection of etanercept into OA knee joints was an effective treatment for pain in moderate and severe OA patients. Furthermore, this finding suggests that TNFα is one factor that induces OA pain.

STUDY DESIGN: Prospective case series. PURPOSE: To examine the clinical efficacy of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion (OLIF) for degenerated lumbar spinal kyphoscoliosis. OVERVIEW OF LITERATURE: The existing surgical procedures for the treatment of spinal kyphotic deformity, including Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection procedures, are invasive in nature. Extreme lateral interbody fusion to provide less invasive treatment of the deformity has been reported, but complications including spinal nerve and psoas muscle injury have been noted. In the current study, we examined the clinical efficacy and complications of OLIF for degenerated lumbar spinal kyphoscoliosis. METHODS: Twelve patients with degenerated lumbar spinal kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with open pedicle screws or percutaneous pedicle screws, without real-time monitoring by electromyography. Visual analog scale score and Oswestry disability index were evaluated before and 12 months after surgery, and fusion rate at OLIF cage, correction of the deformity, total blood loss, and surgical complications were also evaluated. RESULTS: Pain scores significantly improved after surgery (p<0.05). Fusion rate was found to be 90%, balance parameters also improved after surgery (p<0.05), and average total blood loss was less than 350 mL. There was no spinal nerve, major vessel, peritoneal, or urinary injury, or breakage of instrumentation. CONCLUSIONS: OLIF surgery for degenerated lumbar spinal kyphoscoliosis is less invasive than other procedures and good surgical results were produced without major complications.

STUDY DESIGN: Retrospective case series. PURPOSE: To examine the most effective duration of teriparatide use for spinal fusion in women with postmenopausal osteoporosis. OVERVIEW OF LITERATURE: We reported that daily subcutaneous injection of teriparatide (parathyroid hormone) significantly improved bone union after instrumented lumbar posterolateral fusion (PLF) in women with postmenopausal osteoporosis when compared with oral administration of bisphosphonate. However, the most effective duration of teriparatide use for spinal fusion has not been explored. METHODS: Forty-five women with osteoporosis diagnosed with degenerative spondylolisthesis from one of the three treatment groups were evaluated based on: short-duration treatment (average, 5.5 months; n=15; daily subcutaneous injection of 20 µg teriparatide), long-duration treatment (average, 13.0 months; n=15; daily subcutaneous injection of 20 µg teriparatide), and bisphosphonate treatment (average, 13.0 months; n=15; weekly oral administration of 17.5 mg risedronate). All patients underwent PLF with a local bone graft. Fusion rate and duration of bone union were evaluated 1.5 years after surgery. RESULTS: Bone union rate and average duration for bone union were 92% and 7.5 months in the long-duration treatment group, 80% and 8.5 months in the short-duration treatment group, and 70% and 10.0 months in the bisphosphonate treatment group, respectively. Results of bone union rate and average duration for bone union in the teriparatide treatment groups were significantly superior to those in the bisphosphonate treatment group (p<0.05); whereas, significantly superior results were observed in long-duration treatment group when compared with short-duration treatment group (p<0.05). CONCLUSIONS: Daily injection of teriparatide for bone union was more effective than oral administration of bisphosphonate. Furthermore, a longer period of teriparatide treatment for bone union was more effective than a shorter period of same treatment.

PURPOSE: Surgery for lumbar spinal degeneration disease is widely performed. While posterior decompression and fusion are popular, anterior lumbar interbody fusion (ALIF) is also used for treatment. Extreme lateral interbody fusion (XLIF) is commonly used for noninvasive ALIF; however, several complications, such as spinal nerve and psoas muscle injury, have been reported. In the current study, we examined the clinical efficacy and complications of oblique lateral interbody fusion (OLIF) for lumbar spinal degeneration disease. MATERIALS AND METHODS: Thirty-five patients with degenerated spondylolisthesis, discogenic pain, and kyphoscoliosis were examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with or without posterior decompression, without real-time electromyography monitoring. Posterior screws were used in all patients. Visual analog scale (VAS) score and Oswestry Disability Index (ODI) were evaluated before and 6 months after surgery. Surgical complications were also evaluated. RESULTS: Pain scores significantly improved after surgery, compared to those before surgery (p<0.05). There was no patient who underwent revision surgery. There was no spinal nerve, major vessel, peritoneal, or urinary injury. Few patients showed symptoms from psoas invasion. CONCLUSION: OLIF surgery produced good surgical results without any major complication.

An 80-year-old woman presented with severe thoracolumbar kyphosis due to spinal tuberculosis with chronic low back pain and gait disturbance. Radiographs showed T9-L1 bony union in the anterior and posterior longitudinal ligaments. Rigid bony union of the L2 and L3 vertebral bodies, with trapezoid-shaped deformity, a sagittal vertical axis (SVA) of approximately 570 mm, and a severe pelvic posterior inclination, were also evident. No residual tuberculous disease was detected. The patient was treated with kyphoplasty, which included an L2 pedicle subtraction vertebral osteotomy (PSO), and T9-S1 fixation. The procedure yielded a 45° correction in the sagittal alignment and enhanced local stability, resulting in an SVA of 50 mm. Her post-operative lower back pain and the gait disturbance resolved. The osteotomy site showed sufficient bony union 8 months post-operatively. PSO yielded marked improvements and stability with no complications such as pseudoarthritis at the osteotomy site. Also her sagittal alignment was corrected to achieve adequate stability with sufficient activities of daily living and improved quality of life. Vertebral osteotomy on those with rigid deformity gives good and stable clinical outcome.

BACKGROUND: Corrective surgery for kyphoscoliosis patients tend to be highly invasive due to osteotomy. The present case introduce less invasive corrective surgery using anterior oblique lateral interbody fusion (OLIF) technique. CASE PRESENTATION: An 80-year-old Japanese man with a history of Parkinson's disease presented to our hospital because of severe kyphoscoliosis and gait disturbance. Considering the postsurgical complications due to osteotomy, we performed an anterior-posterior combined corrective fusion surgery: OLIF of Lumbar (L) 2-3, L3-4, and L4-5 (Medtronic Sofamor Danek, Memphis, TN, USA) followed by L5-Sacral (S) 1 anterior lumbar fusion via the OLIF approach using an anterior intervertebral cage, and posterior L3-4 and L4-5 facetectomy and posterior fusion using percutaneous pedicle screws from Thoracic (T) 10 to S1 with a T-9 hook system. The surgery was performed in a less invasive manner with no osteotomy, and it improved the sagittal alignments with moderate restoration, which improved the patient's posture and gait disturbance. The patient showed transient muscle weakness of proximal lower extremity contralateral side to the surgical site, which fully recovered by physical rehabilitation 3 months after the surgery. CONCLUSION: The surgical corrective procedure using the minimally invasive OLIF method including L5-S1 fusion showed a great advantage in treating degenerative kyphoscoliosis in a Parkinson's disease patient in its less-invasive approac.