Yasumasa Nishiura

Addition of cultured Schwann cells to tendon autografts and freeze-thawed muscle grafts improves peripheral nerve regeneration.

The effects of addition of Schwann cells on peripheral nerve regeneration through a novel graft material-the tendon autograft-and a conventional freeze-thawed muscle graft, were studied in the rat sciatic nerve. Adult Schwann cell cultures were established from predegenerated nerves. The Schwann cells were added to the autologous grafts by coculture (tendon autograft) or injection (freeze-thawed muscle graft). Both graft types supported adherence of the added Schwann cells. Addition of cultured Schwann cells to the two different graft models improved regeneration by increasing the rate of axonal outgrowth as compared with similar grafts without added cells.

Effects of hyperbaric oxygen treatment on axonal outgrowth in sciatic nerve grafts in rats.

We studied the effect of hyperbaric oxygen treatment on axonal outgrowth in grafts of sciatic nerves in 40 rats. The sciatic nerve was transsected and a 10 mm long segment from the opposite side was immediately sutured in as a nerve graft. Postoperatively 17 animals were treated with 100% oxygen at 3.2 atmospheres absolute pressure for 45 minutes and the treatment was repeated at four and eight hours postoperatively and then every eight hours until evaluation. At seven days the axonal outgrowth was evaluated by immunohistochemical staining of neurofilaments in the nerve grafts. The axonal outgrowth was significantly longer in animals treated with hyperbaric oxygen. We conclude that hyperbaric oxygen can improve nerve regeneration in sciatic nerve grafts in rats.We studied the effect of hyperbaric oxygen treatment on axonal outgrowth in grafts of sciatic nerves in 40 rats. The sciatic nerve was transsected and a 10 mm long segment from the opposite side was immediately sutured in as a nerve graft. Postoperatively 17 animals were treated with 100% oxygen at 3.2 atmospheres absolute pressure for 45 minutes and the treatment was repeated at four and eight hours postoperatively and then every eight hours until evaluation. At seven days the axonal outgrowth was evaluated by immunohistochemical staining of neurofilaments in the nerve grafts. The axonal outgrowth was significantly longer in animals treated with hyperbaric oxygen. We conclude that hyperbaric oxygen can improve nerve regeneration in sciatic nerve grafts in rats.

Correlation of Histopathology With Magnetic Resonance Imaging in Kienböck Disease

PURPOSE Diagnosis and treatment remain controversial for Kienböck disease. A few reports have correlated magnetic resonance imaging (MRI), which is essential for early diagnosis, and histopathology of Kienböck biopsy specimens, but histopathological correlations of whole lunate bones or histological slices compared with MRI images are lacking. The purpose of this study was to compare presurgical MRI scans with corresponding histological slices of Kienböck-diseased lunates. METHODS We excised whole lunates at the time of surgery from 6 patients with Kienböck disease (stage IIIB) undergoing tendon-ball replacement or a Graner procedure. We stained paraffin-embedded, coronally sectioned specimens with hematoxylin-eosin and compared them with presurgical coronal scans using MRI with a 47-mm microscopy surface coil. RESULTS Toward the center of the lunates, the signal intensity in the proton density-weighted images was reduced, whereas the dorsal and palmar sides of the lunates exhibited no changes in intensity. In correlation, histopathological findings revealed strongly disrupted trabeculae toward the center of the lunates and intact trabeculae in the dorsal side of the lunates. Likewise, the necrotic and vitalized bone exhibited low and high signal intensities, respectively, in the proton density-weighted images; however, in the fast-field echo images, there were no correlations with histopathological observations. CONCLUSIONS Proton density-weighted MRIs but not fast-field echo images using a 47-mm microscopy coil reflected the extent and localization of the necrotic area in Kienböck-diseased lunates, as evidenced by comparison with histological analyses of the lunate specimens. CLINICAL RELEVANCE Proton density-weighted MRIs accurately reflect the vascular status of the lunate and may help plan treatment on a case-by-case basis.

Simultaneous gradual lengthening of both proximal and distal nerve stumps for repair of peripheral nerve defect in rats

We investigated nerve regeneration following the repair of a segmental nerve defect induced by direct end‐to‐end neurorrhaphy after simultaneous gradual lengthening of both proximal and distal nerve stumps in rats. A 15‐mm‐long nerve segment was resected from the sciatic nerve of each rat. The proximal and distal nerve stumps, respectively, were directly lengthened at a rate of 1 mm/day using a custom‐made external nerve‐lengthening device. After being lengthened for 14 days, both nerve stumps were refreshed, and direct end‐to‐end neurorrhaphy was performed. For a control, 15‐mm nerve grafting was performed immediately after nerve resection. Nerve regeneration was evaluated by motor nerve conduction velocity, muscle contraction force, and histological studies at 6, 8, and 14 weeks after initial nerve resection in both groups. As a result, at 8 and 14 weeks, the motor nerve conduction velocity was significantly higher in the nerve‐lengthening group than in the autografting group. In addition, at 14 weeks, the tetanic force and wet weight of the gastrocnemius muscle were significantly higher in the nerve‐lengthening group than in the autografting group. Histologically, the mean axonal diameter of myelinated nerve fibers and the total number of myelinated nerve fibers were also significantly higher in the nerve‐lengthening group than in the autografting group for each evaluation period. It appears that the simultaneous gradual lengthening of both proximal and distal nerve stumps might have potential application in the repair of peripheral nerve defects. Muscle Nerve 38: 1474–1480, 2008

Femoral nerve palsy caused by a huge iliopectineal synovitis extending to the iliac fossa in a rheumatoid arthritis case.

We report on a 54-year-old woman with rheumatoid arthritis who had severe femoral nerve palsy affected by a distended synovium in the hip joint. Surgical exploration demonstrated a perforation of the iliopectineal bursa connecting with the hip joint. The patient fully recovered from femoral nerve palsy after surgery. It was considered that synovitis of the hip joint had developed following huge iliopectineal bursitis.

A giant plexiform schwannoma of the brachial plexus: case report.

We report the case of a patient who noticed muscle weakness in his left arm 5 years earlier. On examination, a biloculate mass was observed in the left supraclavicular area, and Tinels sign caused paresthesia in his left arm. Magnetic resonance imaging showed a continuous, multinodular, plexiform tumor from the left C5 to C7 nerve root along the course of the brachial plexus to the left brachia. Tumor excision was attempted. The median and musculocutaneous nerves were extremely enlarged by the tumor, which was approximately 40 cm in length, and showed no response to electric stimulation. We resected a part of the musculocutaneous nerve for biopsy and performed latissimus dorsi muscle transposition in order to repair elbow flexion. Morphologically, the tumor consisted of typical Antoni A areas, and immunohistochemistry revealed a Schwann cell origin of the tumor cells moreover, there was no sign of axon differentiation in the tumor. Therefore, the final diagnosis of plexiform Schwannoma was confirmed.

Repair of the sciatic nerve defect with a direct gradual lengthening of proximal and distal nerve stumps in rabbits.

Background: The current clinical repair method used for the segmental peripheral nerve defect is autogenous nerve grafting. However, this method has several inherent disadvantages. Therefore, the authors have invented an alternative method for repairing the segmental peripheral nerve defect with a direct gradual lengthening of nerve stumps. In this study, for the clinical application, the authors developed a new external nerve-lengthening device for lengthening peripheral nerve stumps daily without anesthesia. Methods: In this study, a nerve segment 20 mm in length was resected from the rabbit sciatic nerve. In the nerve-lengthening group, direct nerve lengthening was performed in the proximal and distal nerve stumps at a rate of 1 mm/day without anesthesia. After being lengthened for 22 days, both proximal and distal nerve stumps were evaluated by immunohistochemical analysis. When confirming that both nerve stumps were successfully lengthened, a direct end-to-end neurorrhaphy was performed. As a control, 20-mm-long autografting was performed immediately after nerve resection. Nerve regeneration was evaluated by electrophysiologic and histologic examination at 16 weeks after the first operation in both the nerve-lengthening and the control groups. Results: The results of both electrophysiologic evaluation and histologic examination showed that the nerve-lengthening group performed significantly better than the autografting group. Conclusion: The gradual nerve-lengthening procedure can be used as an alternative therapeutic method for repairing segmental peripheral nerve defects, which proved to be advantageous over widely adopted autogenous nerve grafting.

New treatment for peripheral nerve defects: Reconstruction of a 2 cm, monkey median nerve gap by direct lengthening of both nerve stumps

We have developed a new treatment for peripheral nerve defects: nerve‐lengthening method, and confirmed the efficacy and safety of our method using cynomolgus monkeys. A 20‐mm defect in the median nerve of monkeys forearms was repaired through the simultaneous lengthening of both nerve stumps with original nerve‐lengthening device. To evaluate nerve regeneration after neurorrhaphy, electrophysiological, histological, and functional recovery were examined and compared to the standard autografting. Nerve conduction velocity, axon maturation, and the result of functional test were superior in the nerve‐lengthening method than in the autografting. And there were no adverse events associated with our method. We concluded that this method is practical for clinical application.

Gradual stretching of the proximal nerve stump induces the growth of regenerating sprouts in rats

We investigated the effect of direct gradual stretching on the proximal nerve stump morphologically. A 10‐mm‐long nerve segment was resected from the sciatic nerve of a rat. The end of the proximal nerve stump was fixed to a small ring and the marking suture was placed at a point 1 mm proximal to the ring. Then, the nerve stump was lengthened at a rate of 1 mm/day via a stretching of the ring using an original external device. After a stretching of 20 days, the distance from the ring to the marking suture became 12 mm. Whereas large mature myelinated axons were observed in the proximal part of the marking, only small axons with thin myelin sheath were observed in the distal part, and the mean axonal diameter showed a significant difference between the two parts. Moreover, the mean internodal length was 172.4 ± 13.4 µm in the distal part of the marking and 1019.0 ± 56.2 µm in the proximal part. The internodal length also showed a significant difference between the two parts. Thus, the axonal diameter and internodal length were consistent with the characteristics of regenerating axons in the distal part. Furthermore, ultrastructural analysis also showed the histological characteristics of axonal regeneration. Thus, a transected proximal nerve stump may be lengthened by axonal regeneration during gradual stretching, and the stimulus of mechanical stretching may induce the growth of regenerating axons.

Repair of peripheral nerve defect by direct gradual lengthening of the distal nerve stump in rats: Effect on nerve regeneration

We investigated the use of direct lengthening of the distal stump of a peripheral nerve to compare the results of nerve regeneration using the direct lengthening method with simple end-to-end suture and autografting in rats. A segment 10 mm long was resected from the rat sciatic nerve (n=18 in each group). The distal nerve stump was fixed to a ring and pulled at a rate of 1 mm/day for 20 days using an original external nerve distraction device. The results showed that the degree of nerve regeneration in the lengthened group was superior to that of the grafted group electrophysiologically and histologically, but there were no significant differences between the lengthened and end-to-end suture groups. We conclude that direct lengthening of the distal stump of a peripheral nerve can promote nerve regeneration similar to that observed in a Wallerian degenerated nerve. We think that this technique may be used for the treatment of peripheral nerve injuries.