稲毛 一秀

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.

Previously, a rat model of chronic compressive myelopathy that uses a water-absorbing polymer inserted under a spinal lamina was reported. However, the best size and coefficient of expansion of the polymer sheet have not yet been established. The aim of the present study was to optimize these properties in an ideal rat model of cervical compressive myelopathy. Thirty rats were used in this study. A sheet of water-absorbing polymer was inserted under the cervical laminae. Rats were divided randomly into five experimental groups by the expansion rate (350 or 200%) and thickness (0.5 or 0.7 mm) and the control. After the surgery, the severity of paralysis was evaluated for 12 weeks. At 12 weeks after the surgery, cresyl violet staining was performed to assess the number of motor neurons in the anterior horn at the C4/C5 segment and Luxol Fast Blue staining was performed to assess demyelination in the corticospinal tract at the C7 segment. 'Slow-progressive' paralysis appeared at 4-8 weeks postoperatively in rat models using sheets with 200% expansion. By contrast, only temporary paralysis was observed in rat models using sheets with 350% expansion. A loss of motor neurons in the anterior horn was observed in all groups, except for the control. Demyelination in the corticospinal tract was observed in rat models using sheets with 200% expansion, but not rat models using sheets with 350% expansion. A polymer sheet that expands its volume by 200% is an ideal material for rat models of cervical compressive myelopathy.

腰痛患者65名を対象にしてdual energy X-ray absorptiometry(DXA)法とbioelectrical impedance analysis(BIA)法の四肢筋量の相関関係と実際の測定値の差異について調査した.四肢筋量測定において,DXA法とBIA法の測定値は強い正の相関関係を認めたが,BIA法の測定値が有意に高値であった.また,四肢筋量と骨密度も正の相関関係を認めた.骨粗鬆症患者130例において,骨粗鬆症薬の筋量に対する効果について調べた.骨粗鬆症がなく経過観察を行ったコントロール群に比し投与後6ヵ月で骨密度は有意に増加したが,下肢筋量は有意に減少した.ビタミンD併用患者では下肢筋量の減少量が有意に少なかった.(著者抄録)

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.

われわれ痛み診療に従事する医師にとって、骨粗鬆症と腰痛は非常に密接した病態であり、それらの機序を正確に理解することが診断および治療の観点から重要である。骨粗鬆症患者が腰痛を訴える原因として、(1)脊椎疾患の合併、(2)骨折、(3)骨粗鬆化、(4)サルコペニア(加齢性筋肉減少症)の4つが注目されている。重要な点は、これらの原因は独立して存在するのではなく、お互いが重複して存在することが多いということである。このことを常に念頭に置き、腰痛のある骨粗鬆症患者を診察、治療していくことが重要であると考える。(著者抄録)

PURPOSE: Recently, lateral interbody fusion (LIF) has become more prevalent, and evaluation of lumbar nerves has taken on new importance. We report on the assessment of anatomical relationships between lumbar nerves and vertebral bodies using diffusion tensor imaging (DTI). METHODS: Fifty patients with degenerative lumbar disease and ten healthy subjects underwent DTI. In patients with lumbar degenerative disease, we studied nerve courses with patients in the supine positions and with hips flexed. In healthy subjects, we evaluated nerve courses in three different positions: supine with hips flexed (the standard position for MRI); supine with hips extended; and the right lateral decubitus position with hips flexed. In conjunction with tractography from L3 to L5 using T2-weighted sagittal imaging, the vertebral body anteroposterior span was divided into four equally wide zones, with six total zones defined, including an anterior and a posterior zone (zone A, zones 1-4, zone P). We used this to characterize nerve courses at disc levels L3/4, L4/5, and L5/S1. RESULTS: In patients with degenerative lumbar disease, in the supine position with hips flexed, all lumbar nerve roots were located posterior to the vertebral body centers in L3/4 and L4/5. In healthy individuals, the L3/4 nerve courses were displaced forward in hips extended compared with the standard position, whereas in the lateral decubitus position, the L4/5 and L5/S nerve courses were displaced posteriorly compared with the standard position. CONCLUSIONS: The L3/4 and L4/5 nerve roots are located posterior to the vertebral body center. These were found to be offset to the rear when the hip is flexed or the lateral decubitus position is assumed. The present study is the first to elucidate changes in the course of the lumbar nerves as this varies by position. The lateral decubitus position or the position supine with hips flexed may be useful for avoiding nerve damage in a direct lateral transpsoas approach. Preoperative DTI seems to be useful in evaluating the lumbar nerve course as it relates anatomically to the vertebral body.

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.

慢性腰痛の原因は多岐にわたることが多く、診療にあたっては患者の主訴と身体所見をもとに十分に検討する。慢性腰痛の正確な診断に必要となるのが疼痛の基礎知識(侵害受容性疼痛、神経障害性疼痛など)や腰痛に関連する解剖学的知識(椎間板・椎体の神経支配や椎間関節における連結、矢状面アライメントなど)である。下肢痛のある患者や臀部痛の関与する患者は神経障害性疼痛に伴う慢性腰痛である可能性が高く、疼痛部位とその分布にも注意をはらうようにする。また椎間孔狭窄など見逃されやすい画像所見がある一方、必ずしもすべての画像所見が症状に直結するわけではない。これらの事項を念頭に置いたうえで患者の病態の正確な把握が重要であるが、慢性腰痛の実地臨床では痛みを完全に消失させることよりもADLやQOLには支障をきたさない程度に痛みを許容することが治療の成功につながることも多く、医療従事者側の十分な理解と患者に対する入念な教育が重要である。(著者抄録)

【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、胸腰椎の後彎角は術後と比し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彎増強、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。術後の後彎角は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ヵ月の段階での局所最終後彎角は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。(著者抄録)

Study Design: Retrospective cohort study. Purpose: To assess bone mineral density (BMD) and bone metabolism ≥27 years after surgery in female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS) during adolescence and to determine their associations with physical performance. Overview of Literature: There are no studies investigating postsurgical BMD in middle-aged AIS patients. Methods: This study included 23 patients who provided informed consent among 229 female patients with AIS who underwent spinal fusion from 1968 until 1988. Average age at the time of observation was 48.8 years. BMD was measured at the left femoral neck, and the levels of two bone metabolism markers-procollagen type 1 N-terminal propeptide (P1NP) and tartrate-resistant acid phosphatase 5b (TRACP-5b)-were measured from blood samples. Physical performance was measured using grip strength, sit-ups, sit-and-reach, side step, and standing long jump. Results: Mean BMD was 0.784 g/cm2. According to the World Health Organization diagnostic criteria, one subject (4.3%) had osteoporosis, whereas nine subjects (39.1%) had osteopenia. In patients with osteoporosis or osteopenia, P1NP and TRACP-5b levels were high, and BMD loss was because of high metabolic turnover. All calculated standard scores for physical performance were lower in the study cohort than in healthy individuals. There was a positive correlation between BMD and the standard score for grip strength, whereas there were weak positive correlations between BMD and the standard scores for side step and standing long jump. Conclusions: In female AIS patients who underwent spinal fusion in adolescence, 4.3% and 39.1% had osteoporosis and osteopenia, respectively, ≥27 years after surgery. Exercise performance of these patients was poor compared with the national standards. In these patients, increased physical activity should be encouraged to prevent BMD loss in middle age.