New Predictive Index for Lumbar Paraspinal Muscle Degeneration Associated With Aging.

STUDY DESIGN: A cross-sectional imaging study of paraspinal muscle degeneration using a new index for easy evaluation. OBJECTIVE: To examine the natural progression of age-related changes in the lumbar paraspinal muscles and to verify the validity of our new index for evaluating paraspinal muscle degenerationSUMMARY OF BACKGROUND DATA.: Measurement of paraspinal muscle morphology is an effective method for reflecting atrophy and fat infiltration, but it is complicated to perform. Therefore, we focused on the groove between lumbar paraspinal muscles as a simple index for evaluating paraspinal muscle degeneration. METHODS: A total of 160 subjects aged 10 to 88 years (10 male and 10 female subjects in each decade) with lumbar lordosis of more than 20° were included. Body mass index (BMI) was calculated. Sagittal T2-weighted magnetic resonance imaging (MRI) was used to measure lumbar lordosis, while axial T2-weighted MRI was used to measure cross-sectional area (CSA) and fat infiltration rate of the paraspinal muscles at the intervertebral disc level from L1 to L5. To quantify the depth of the groove between the paraspinal muscles, our own image index (lumbar indentation value (LIV): equal to the length of the bulge of the muscle to the attachment of the spinous process), also was measured. We then determined the correlation between LIV and paraspinal muscle degeneration. RESULTS: There were no significant differences in BMI and lumbar lordosis between age groups. CSA of the paraspinal muscles tended to decrease with age, and fat infiltration rate increased with age. There was a negative correlation between CSA and fat infiltration rate at all levels (r = -0.474 to -0.634). LIV decreased significantly with age and strongly correlated with CSA at all levels (r = 0.709-0.789). CONCLUSION: Our new index is a simple and effective parameter for evaluating paraspinal muscle degeneration associated with aging. LEVEL OF EVIDENCE: 4.

Bilateral discoid medial menisci accompanied by distal arthrogryposis: a case report.

Discoid meniscus shows a propensity for the lateral side, and bilateral discoid medial meniscus is extremely rare. The present patient had a history of windblown hand and clubfoot, and bilateral discoid medial meniscus was associated with distal arthrogryposis. There has been no previous case report about the coexistence of meniscal abnormalities and distal arthrogryposis. While the association between distal arthrogryposis and meniscal abnormalities is unknown, it is interesting that discoid medial meniscus (a rare meniscus abnormality) occurred in the presence of arthrogryposis. We performed bilateral arthroscopic partial meniscectomy (reshaping) to treat discoid meniscus in this case, and the patient used outer wedge arch supports postoperatively. Neither relapse of meniscal symptoms nor arthrosis has occurred postoperatively in this patient, but long-term follow-up is considered to be necessary.

Intradural extramedullary hemangioblastoma differentiated by MR images in the cervical spine: a case report and review of the literature.

We report a rare case of hemangioblastoma existing in the intradural extramedullary location diagnosed by magnetic resonance imaging (MRI) examination alone. A 46-year-old man gradually developed numbness in his lower extremities. MR images revealed a tumor shadow located posterior to the spinal cord at C5-C7. Small signal void shadows were continuously observed from C1 to C5 in the region cranial to the tumor, indicating the presence of enlarged vessels. Under microscopic observation, the tumor with accompanying vessels was resected totally via hemilaminectomy. The postoperative course was uneventful, and MR images obtained 4 months after the operative procedure demonstrated total removal of the tumor and the abnormal vessels. In this case, recognizing the abnormally enlarged vessels outside the tumor mass preoperatively led us to the correct diagnosis on MR images.

Creating bioabsorbable Schwann cell coated conduits through tissue engineering.

Enormous effort has been devoted to the generation of a synthetic guidance conduit for nerve repair instead of utilizing autograft. Several studies show neural guidance conduit is more effective when coated with Schwann cells. In this study, we synthesized bioabsorbable conduit consist of L-lactide and epsilon-caprolactone which was useful clinically and examined adhesion of Schwann cells to bioabsorbable conduits. In vivo studies were done in which these polymer conduits coated with Schwann cells were implanted across a 12 mm gap in the rat sciatic nerve. Silicone conduits were implanted across the same gap as control. At 12 weeks, axonal regeneration was observed in the midconduit region of these polymer conduits and was not in control. This study assesses the feasibility of a tissue engineering approach to constructing bioabsorbable conduits coated with Schwann cells.

Mutation (D472Y) in the type 3 repeat domain of cartilage oligomeric matrix protein affects its early vesicle trafficking in endoplasmic reticulum and induces apoptosis.

Cartilage oligomeric matrix protein (COMP) is a large pentameric extracellular glycoprotein found in cartilage, tendon, and synovium, and plays structural roles in cartilage as the fifth member of the thrombospondin family. Familial mutations in type 3 repeats of COMP are known to cause pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (EDM1). Although such mutations induce enlarged rough endoplasmic reticulum (rER) as a morphological change, the metabolic trafficking of mutated COMP remains unclear. In transfected COS7 cells, wild-type COMP was rapidly secreted into culture medium, while the great majority of COMP with the type 3 repeats mutation (D472Y) remained in the cells and a small portion of mutated COMP was secreted. This finding was followed up with a confocal study with an antibody specific to COMP, which demonstrated mutated COMP tightly associated with abnormally enlarged rER. Phosphorylated eIF2alpha, an ER stress protein, was expressed as a pathological reaction in virtually all COS7 cells expressing mutated but not wild-type COMP. Moreover, COS7 cells expressing mutated COMP exhibited significantly more apoptotic reaction than those expressing wild-type COMP. Pathological accumulation of COMP in rER and apoptosis in COS7 cells that were induced by the mutation (D472Y) in COMP imply that COMP mutations play a role in the pathogenesis of PSACH.

Palsy of the C5 nerve root after midsagittal-splitting laminoplasty of the cervical spine.

STUDY DESIGN: The imaging characteristics of postoperative C5 nerve root palsy after midsagittal-splitting laminoplasty for cervical myelopathy, including those observed on plain radiography, computed tomography, and magnetic resonance imaging, were analyzed. OBJECTIVE: To investigate the imaging findings that predict occurrence of C5 nerve root palsy after midsagittal-splitting laminoplasty. SUMMARY OF BACKGROUND DATA: There have been several reports on imaging findings for postoperative nerve root palsy after open-door laminoplasty. However, there have been no detailed reports on imaging characteristics that predict the occurrence of nerve root palsy after midsagittal-splitting laminoplasty. METHODS: The study included 45 consecutive patients undergoing midsagittal-splitting laminoplasty with sufficient pre- and postoperative imaging examinations: 27 patients with cervical spondylotic myelopathy (CSM), 14 patients with ossification of the posterior longitudinal ligament (OPLL), and 4 patients with cervical disc herniation. Characteristics of pre- and postoperative plain radiographs, computed tomography scans, and magnetic resonance images were compared between the patients with and those without C5 nerve root palsy. RESULTS: Palsy of the C5 nerve root developed in 4 patients, and did not develop in 41 patients. Of the four patients with C5 nerve root palsy, one had CSM and the other three had OPLL. The incidence of C5 nerve root palsy involved 3 of 14 patients with OPLL patients (21.4%) and 1 of 31 patients without OPLL (3.2%) (P = 0.08). For both diseases, the patients with palsy tended to have increased postoperative cervical lordosis (P = 0.21). As for anterior compression on the spinal cord at C3, the P value for the comparison between the group with and the group without palsy was 0.07 for preoperative compression and 0.01 for postoperative compression. CONCLUSIONS: The preliminary data suggest that patients who have OPLL with marked anterior compression on spinal cord at C3 can be at risk for postoperative C5 nerve root palsy after midsagittal-splitting laminoplasty. Also, a postoperative increase in cervical lordosis may be the cause of postoperative nerve root palsy.

Idiopathic spinal cord herniation in the thoracic spine as a cause of intractable leg pain: case report and review of the literature.

We recently experienced a case of idiopathic spinal cord herniation in the upper thoracic spine with development of severe unilateral leg pain: a 57-year-old man who had suffered from severe leg pain for about 15 years with lack of abnormality in his lumbar spine. On MRI of the thoracic spine, however, the spinal cord at T2-T3 was bent forward with dilatation of the posterior subarachnoid space. In combination with the findings of computed tomographic myelography, we diagnosed idiopathic spinal cord herniation and performed a surgical treatment. Immediately after the operation, his leg pain disappeared. Therefore, we concluded that the cause of his leg pain was herniation of the thoracic spinal cord.

Polyethylene wear particles in synovial fluid after total knee arthroplasty.

The aims of the current study were to examine polyethylene particles in synovial fluid at an early stage, and to compare a newly introduced medial pivot total knee prosthesis with an established posterior-stabilized total knee prosthesis. Synovial fluid was obtained 1 year after knee arthroplasty from 17 patients with well-functioning prostheses (22 knees, 11 posterior-stabilized prostheses and 11 medial pivot prostheses) under complete sterile conditions. Polyethylene particles were isolated and analyzed by scanning electron microscopy. Particle size (equivalent circle diameter) was 0.78 +/- 0.08 microm (mean +/- standard error) in posterior-stabilized prostheses and 0.67 +/- 0.06 microm in medial pivot prostheses. Particle shape (aspect ratio) was 2.30 +/- 0.22 in posterior-stabilized prostheses and 1.90 +/- 0.16 in medial pivot prostheses. The total numbers of particles were 1.16 +/- 0.57 x 10(8) in posterior-stabilized prostheses and 9.01 +/- 2.95 x 10(6) in medial pivot prostheses. Particles were smaller and rounder in medial pivot prostheses than in posterior-stabilized prostheses, but the differences were not significant. The difference in the common logarithm of particle number was significant. The medial pivot prosthesis generated less wear particles than the posteriorstabilized prosthesis, and these findings may have an impact on the incidence of osteolysis and aseptic loosening.

Biochemical change in joint fluid after isometric quadriceps exercise for patients with osteoarthritis of the knee.

OBJECTIVE: The purpose of this study was to analyze the biochemical changes in the joint fluid, and pain relief resulting from isometric quadriceps exercise in patients with osteoarthritis of the knee. DESIGN: Nineteen osteoarthritic knees in 17 patients with joint effusion were included. The patients performed isometric quadriceps exercise for 3 months. Isometric muscle torque at 30 and 60 degrees flexion, pain as measured using the visual analog scale and biochemical markers in joint fluid were evaluated before and after the exercise. RESULTS: Pain score decreased from 3.9 to 2.3 after 12 weeks of exercise (P<0.001). Extension torque at 30 and 60 degrees knee flexion significantly increased from 4.7 to 6.9 kgm (47% increase, P<0.001) and from 10.8 to 12.6 kgm (17% increase, P<0.005) after 12 weeks of exercise. The molecular weight of hyaluronan increased from 2.11 to 2.40x10(6)(P<0.05) and the viscosity of joint fluid increased from 45.8 to 59.8 mPas after 12 weeks of exercise (P<0.05). Chondroitin 4-, 6-sulfate concentration in joint fluid decreased from 81.9 to 75.5 nmol/ml (P<0.05). CONCLUSIONS: Isometric quadriceps exercise resulted in significant changes in joint fluid biochemical parameters, and these changes, at least in part, may explain the ameliorative effect of muscle exercise for osteoarthritis of the knee.

Piriformis syndrome diagnosed by cauda equina action potentials: report of two cases.

STUDY DESIGN: Evaluation of recorded potentials from the lumbar spine after stimulation of the peroneal nerve in patients with piriformis syndrome is reported. OBJECTIVES: To report a new method of diagnosis of piriformis syndrome. SUMMARY OF BACKGROUND DATA: Clinically, the Freiberg and Pace signs were used to diagnose this entity. Among imaging examinations, computed tomography and magnetic resonance imaging have been used. An electrophysiological method using H reflex has also been reported. However, the best method for diagnosis of piriformis syndrome has yet to be clearly established. METHODS: After having an epidural electrode inserted into the lumbar spine, patients lay on their back. Cauda equina action potentials were recorded with the epidural electrode at L3/4 after stimulation of the peroneal nerve at the fibular head. As a control, the potentials were recorded with the hip and knee extended. Potentials were then also recorded with the hip flexed, and then with the hip flexed and internally rotated to stress the sciatic nerve by the piriformis muscle. RESULTS: We observed changes in amplitudes and latencies of recorded potentials. Amplitude decreased to about 70% of the control value in one case and to 67% in the other. On the nonaffected side, however, this amplitude did not decrease below 90%. The latency was also delayed on the affected side, but not on the nonaffected side. CONCLUSIONS: Recording of evoked potentials from the lumbar spine with stress to the affected leg was useful for diagnosing piriformis syndrome.

Analysis of the spastic gait caused by cervical compression myelopathy.

We evaluated the spastic gait of patients with cervical myelopathy with a three-dimensional gait analysis system. Fifteen patients with cervical myelopathy (S group) were investigated. The results obtained were compared with those of normal volunteers (N group). The S group exhibited significant reduction of gait velocity and step length (p < 0.01). In the knee flexion-extension curve, two peaks were observed in the N group. In the S1 group (symptomatic period <1 year), the anterior peak was not smooth, whereas in the S2 group (symptomatic period >1 year), no peak was observed. The pelvis tilted to the side of the standing leg in the N group. However, in the S1 group, this tilting was much less pronounced, and in some patients tilting toward the nonsupporting leg was observed. In the S2 group, the pelvis again tilting toward the supporting side was observed.

Human monocyte response to retrieved polymethylmethacrylate particles.

The purpose of this study was to compare retrieved polymethylmethacrylate (PMMA) particles from failed total hip arthroplasties in terms of size, shape, and the response of human monocytes with commercially available particles. PMMA particles were isolated from peri-implant tissues of five failed cemented total hip arthroplasties using tissue digestion and a sucrose density gradient technique. Prepolymerized cement powder and those from which barium sulfate had been removed were examined for comparison. After exposure of peripheral human monocytes to PMMA particles, tumor necrosis factor-alpha and interleukin-6 in medium were measured by using enzyme-linked immunosorbent assays. Image analysis revealed that retrieved particles were larger (retrieved: 1.24 microm; prepolymerized cement powder: 0.83 microm; barium sulfate-free powder: 0.87 microm) and were more irregular in shape and rougher than commercially available particles. Cytokine release was increased by all PMMA particle species. However, commercially available PMMA particles stimulated the release of necrosis factor-alpha and interleukin-6 more strongly than did retrieved particles at very high doses. The observed difference in monocyte response might be due to the volume of the challenged particles. Another possible reason for the difference might be alteration of the surface chemistry of particles in situ and the difference in surface morphology between them.

Experimental study of polarity in reversing cable nerve grafts.

To evaluate the effect of cable nerve graft polarity, the bilateral common peroneal nerves in 12 rabbits were excised to create 20-mm nerve gaps. These gaps were repaired with cable grafts using three strands of 20-mm ipsilateral sural nerves. In the left leg, the sural nerves were grafted with the original orientation. In the right leg, the nerve graft polarity was reversed 180 degrees. Six months later, motor conduction velocities were evaluated, and the bilateral anterior tibial muscles and extensor digitorum longus muscles were measured. The nerves were harvested and analyzed histologically. Motor conduction velocity was 37.4+/-4.1 m/s in the reversed group, and 36.6+/-5.5 m/s in the control group. The weight of the muscles was 7.2+/-0.8 g in the reversed orientation, and 7.0+/-1.0 g in the original orientation. None of the differences was statistically significant. Histologically, the axon counts and the axonal density distal to the nerve graft also showed no differences between groups. The sural nerves used did not have a major branch and their diameter was almost the same throughout its length. Reversing nerve graft polarity of a cable graft did not affect nerve regeneration electrophysiologically or histologically.

Transient osteoporosis of the femoral condyle: a case report.

In this paper, we describe a patient with transient osteoporosis of the femoral condyle. A differential diagnosis should be made for osteonecrosis, infectious disorders, and infiltrative neoplasms based on the normal laboratory findings and diffuse bone edema pattern in MRI. Since this disorder is self-limiting, both the surgeon and clinician should be aware of this condition and must avoid unnecessary intervention.

Hydroxyapatite granule graft combined with recombinant human bone morphogenic protein-2 for solid lumbar fusion.

The purpose of this study was to evaluate the availability of recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with hydroxyapatite (HA) and autogenous bone. Posterolateral intertransverse fusion between the fifth and sixth lumbar vertebrae was performed in 27 adult Japanese white rabbits. These 27 rabbits were classified into three groups: the autogenous bone group, the HA group, and the bone morphogenic protein (BMP) group. In the HA group, HA (0.5 g) mixed with iliac bone was grafted. In the BMP group, HA (0.5 g) soaked with rhBMP-2 (100 mg) and iliac bone was grafted. At 6 weeks after the procedure, bone union was evaluated. In the BMP group, all cases showed solid bone union, and fusion masses were stiffer than the masses obtained in the other group. Biomechanically and histologically, grafts of HA soaked with rhBMP-2 and iliac bone was clearly effective in obtaining a solid intertransverse arthrodesis.

Calcium phosphate bone cement for treatment of distal radius fractures: a preliminary report.

Distal radius fractures in osteoporotic patients are often complicated with a residual deformity and a subsequent stiff and painful wrist. The aim of this study was to evaluate the usefulness of calcium phosphate bone cement (CPC95) in the treatment of these fractures. Seven Colles type fractures in seven patients (all female; average age, 58 years) were treated. After a closed reduction, the fractures were fixed either by percutaneous pinning or by external skeletal fixation. The CPC95 was then injected into the cancellous bone defect through a small dorsal incision. The functional and radiological results were evaluated for up to 1 year. All patients were graded as good or excellent within 3 months, and all were graded as excellent at the final follow-up. The average duration of immobilization was 3.5 weeks. The overall shortening of the radius was 2.3 mm. In one patient, CPC95 extruded into the extensor tendon sheath and was surgically removed. Injection of CPC95 is a promising augmentation of osteosynthesis for distal radius fractures, although a prospective control study is mandatory to prove the usefulness of this material. The equipment and surgical technique should be refined to avoid the extrusion of CPC95.

Dumbbell-shaped meningioma with cystic degeneration in the thoracic spine: a case report.

STUDY DESIGN: A case report of dumbbell-shaped meningioma in the thoracic spine with cystic degeneration for which a combined posterior microscopic and anterior thoracoscopic approach was used is described. OBJECTIVES: To report a rare case of dumbbell-shaped meningioma, and to describe a thoracoscopic surgical approach for paravertebral tumor. SUMMARY OF BACKGROUND DATA: Dumbbell-shaped tumors arising from nerve root sheaths are very common. However, a dumbbell-shaped meningioma is relatively rare, and reports on thoracoscopic resection of dumbbell and paravertebral tumors are still very few in number. METHODS: The dumbbell meningioma was managed surgically. Because of the paravertebral tumor's intrathoracic expansion, a combined posterior and anterior approach was used. With the posterior approach, microscopic resection using hemilaminotomy was performed, whereas with the anterior approach, the thoracoscopic approach was used instead of thoracotomy. RESULTS: Complete resection of the tumor was performed successfully. The patient regained his functional ability to walk soon after surgery because of less pain than with thoracotomy. CONCLUSIONS: With combined microscopic and thoracoscopic surgery, dumbbell-shaped meningioma could be completely resected. The thoracoscopic approach for the removal of a paravertebral tumor can be a good alternative to thoracotomy.

Single-stage excision of hemivertebrae via the posterior approach alone for congenital spine deformity: follow-up period longer than ten years.

STUDY DESIGN: Evaluation of the long-term results for single fully segmented hemivertebrae were subjected to single-stage excision via posterior approach alone. OBJECTIVES: To describe the long-term results of this procedure. SUMMARY OF BACKGROUND DATA: In the case of congenital spinal deformity caused by a single, full hemivertebra, excision of the hemivertebra is ideal for obtaining a good correction percentage even in short segments. Recently, single-stage excision of a hemivertebra using a combined anterior and posterior approach has been reported. METHODS: Five patients with a hemivertebra underwent surgery. The hemivertebra involved the thoracolumbar region in three cases and the lumbosacral region in two cases. After removal of a lamina of the hemivertebra, the body of the hemivertebra was visualized easily because the spinal cord had deviated to the concave side of the curve. The vertebral body, along with its cranial and caudal discs, was curetted with this approach. Thereafter, bone chips were grafted into the defect created by vertebrectomy. The results of this surgical procedure, especially those observed during long-term follow-up evaluation, were investigated. RESULTS: For patients with a thoracolumbar hemivertebra, scoliosis improved from 49 degrees +/- 6 degrees to 22.3 degrees +/- 3.5 degrees, for a 54.3% correction. The correction ratio for kyphosis was 67.4%. Over an average 12.8-year follow up period, loss of scoliotic curvature correction was only 3.7 degrees. In contrast, the hemivertebral correction ratio for patients with a lumbosacral hemivertebra remained 32.5% because of difficulty using internal fixation associated with patient age. At the most recent follow-up assessment, one patient exhibited deterioration of coronal spinal balance. CONCLUSION: The described procedure was less invasive because it avoided an anterior approach, yet it yielded satisfactory long-term results for thoracolumbar hemivertebrae.