阿部 幸喜

STUDY DESIGN: Retrospective observational study. PURPOSE: We considered the relationship between spinal alignment and skeletal muscle mass on clinical outcomes following a surgery for lumbar spinal stenosis (LSS). OVERVIEW OF LITERATURE: There are no reports of preoperative factors predicting residual low back pain following surgery for LSS. METHODS: Our target population included 34 women (mean age, 74.4 years) who underwent surgery for LSS. Prior to and 6 months after the surgery, systemic bone mineral density and lean soft tissue mass were measured using dual-energy X-ray absorptiometry. Skeletal muscle mass index (SMI) was calculated as the sum of the arm and leg lean mass in kilograms divided by height in meters squared. The spinal alignment was also measured. Clinical outcomes were evaluated using the Japanese Orthopedic Association scoring system, leg and low back pain Visual Analog Scale, and Roland-Morris Disability Questionnaire (RDQ). Additionally, we examined the bone mineral density, skeletal muscle mass, and spinal alignment before and after the surgery. We used the Spearman correlation coefficient to examine the associations among clinical outcomes, preoperative muscle mass, and spinal alignment. RESULTS: Sarcopenia (SMI <5.46) was observed in nine subjects (26.5%). Compared with normal subjects (SMI >6.12), RDQ was significantly higher in subjects with sarcopenia (p =0.04). RDQ was significantly negatively correlated with SMI (r =-0.42, p <0.05). There was a significant positive correlation between postoperative RDQ and pelvic tilt (PT; r =0.41, p <0.05). SMI and PT were significantly negatively correlated (r =-0.39, r <0.05). CONCLUSIONS: Good postoperative outcomes were negatively correlated with low preoperative appendicular muscle mass, suggesting that postoperative outcomes were inferior in cases of decreased appendicular muscle mass (sarcopenia). Posterior PT due to decreased limb muscle mass may contribute to postoperative back pain, showing that preoperatively reduced limb muscle mass and posterior PT are predictive factors in the persistence of postoperative low back pain.

In daily practice, when CT or MRI does not show a pathological lesion in a patient with persistent abnormal neurological signs, it is important to obtain imaging studies of the spine in dynamic position.

PURPOSE: Advanced glycation end products (AGEs) have been implicated in the pathogenesis of sarcopenia. The objective of the study was to investigate the prevalence of sarcopenia in degenerative lumbar scoliosis (DLS), and the relationship between biochemical markers including major AGEs, pentosidine, and DLS in older women. METHODS: Our study participants were 20 elderly women with idiopathic DLS (mean age 76.4 years, range 56-88). Nineteen age- and sex-matched volunteers (mean age 74.0 years, range 62-86) served as controls. Spinal and femoral BMD of all participants was measured using dual-energy X-ray absorptiometry. We used a bioelectrical impedance analyzer to analyze body composition, including appendicular skeletal muscle mass index [SMI; appendicular lean mass (kg)/(height (m)]2. SMI < 5.75 was considered diagnostic for sarcopenia. Coronal and sagittal spinal alignments were measured. The following biochemical markers were measured: serum and urinary pentosidine, serum homocysteine, 1,25(OA)2D, and 25(OH)D. The level of each variable was compared between DLS and controls. The relationship between biochemical markers including pentosidine and DLS was examined. RESULTS: Sarcopenia was observed at a high prevalence in participants with DLS: 50% compared with 15.8% of healthy controls. Height, weight, femoral BMI, appendicular lean mass, total lean mass, and SMI all had significantly lower values in the DLS group. Serum pentosidine was significantly higher for the DLS group compared with controls. Correlations with serum pentosidine revealed a significant positive correlation between lumbar scoliosis, pelvic tilt, and pelvic incidence-lumbar lordosis mismatch, and a significantly negative correlation between thoracic kyphosis (P < 0.05). CONCLUSIONS: We found that sarcopenia was involved in DLS, and high serum pentosidine levels are associated with severity of coronal and sagittal malalignment in older women, suggesting that high levels of AGEs are a potential biomarker for the progression of lumbar scoliosis and kyphotic deformity. Further studies are needed to clarify the pathogenesis of DLS.

イバンドロネー卜錠剤を投与した閉経後骨粗鬆症患者60例(平均75.0±7.1歳)を対象に、薬剤継続率、骨粗鬆症改善効果(骨吸収抑制および骨密度上昇)を検討した。薬剤継続率は投与後6ヵ月時点で76.7%(46例)であった。また、副作用発生頻度は11.7%(7例)で、インフルエンザ様症状3例、歯の違和感2例、内服後胃部不快感2例であった。副作用が発生した症例における薬剤継続率は57.1%であった。骨粗鬆症改善効果は、投与前に比べ投与後6ヵ月で骨吸収マーカーTRACP-5b値は有意に低下し、平均腰椎YAM値は有意に増加した。投与6ヵ月による骨密度レスポンス率(骨密度が増加した患者の割合)は95.7%であった。以上、イバンドロネート錠剤の高い薬剤継続率、骨粗鬆症改善効果(骨吸収抑制効果、骨密度上昇効果、骨密度レスポンス率)が示された。

INTRODUCTION: Discogenic back pain remains poorly understood with respect to etiopathogenesis, despite being a considerable burden. We sought to examine the expression of vascular endothelial growth factor in injured intervertebral discs in rat caudal vertebrae. METHODS: Forty-eight male Sprague Dawley rats were assigned to 2 groups according to disc puncture injury: puncture (n = 32) or non-puncture (n = 16). Disc puncture was performed percutaneously such that the incision would be in the primary plane of motion for the coccygeal discs 5-6, 6-7, and 7-8. A 26-gauge needle was used to puncture each disc 10 times. Punctured discs were examined histologically by hematoxylin and eosin staining at 1, 7, 14, and 28 days post-injury. RESULTS: Vascular endothelial growth factor was localized immunohistochemically, and determined quantitatively using an enzyme-linked immunosorbent assay. Peak inflammation occurred on the 7th day post-injury, but tissue degeneration continued until day 28. Local expression of vascular endothelial growth factor tended to be highest in the annulus fibrosus on the 7th and 14th days after puncture injury. The level of vascular endothelial growth factor was highest 1-day post-injury, and then gradually decreased thereafter. Furthermore, vascular endothelial growth factor levels in the puncture group were significantly higher than those in the non-puncture control group (p < 0.05). CONCLUSIONS: We found increased expression of the inflammatory cytokine vascular endothelial growth factor in injured intervertebral discs, suggesting that vascular endothelial growth factor may be clinically important in discogenic back pain.

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.

OBJECTIVE: We investigated high resolution diffusion tensor imaging (DTI) of lumbar nerves with reduced field of view (rFOV) using 3 T MRI. METHODS: DTI measured with rFOV was compared with conventional FOV (cFOV) 3.0 T MRI in 5 healthy volunteers and 10 patients with degenerative lumbar disorders. The intracanal, foramina and extraforamina of the L5 nerve were established as the regions of interest and fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) values were measured. Image quality for tractography and FA maps and ADC maps, interindividual and intraindividual reliability of FA and ADC, and signal-to-noise (SNR) were studied. RESULTS: Both of image qualities with tractography, FA map and ADC map showed that lumbar nerves were more clearly imaged with the rFOV. Intraindividual reliability was higher with rFOV compared with the conventional method for ADC values, while interindividual reliability was higher for both FA values and ADC values with the rFOV method over the conventional method (p < 0.05). Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal (p < 0.05). CONCLUSION: rFOV enabled clearer imaging of the lumbar nerve, allowing for more accurate measurement of FA and ADC values. Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal. To our knowledge, this research showed for the first time the usefulness of rFOV in patients with degenerative lumbar disorders. High resolution DTI using rFOV may become useful in clinical applications because visualization of nerve entrapments and quantification of DTI parameters may allow more accurate diagnoses of lumbar nerve dysfunction. Advances in knowledge: Compared with traditional methods, rFOV allows for clear imaging of the lumbar nerve and enables accurate measurements of the FA and ADC values. High-resolution DTI with rFOV may be used to visualize nerve entrapments and allow for more accurate diagnosis of DTI parameter quantification with opportunities for clinical applications.

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.