Yoshiharu Takemitsu

The effects of mechanical compression and hypoxia on nerve root and dorsal root ganglia. An analysis of ectopic firing using an in vitro model.

Study Design This study analyzed in vitro experiments of ectopic firing evoked by mechanical compression or hypoxia of canine lumbar dorsal roots with dorsal root ganglia using an in vitro model. Objectives The results were correlated to understand the pathophysiology of radiculopathy, which manifests abnormal sensation and pain. Summary of Background Data It has been speculated that blood flow in the nerve root and mechanical compression play major roles in the production of radiculopathy symptoms. However, no precise experimental studies have been conducted on the relationship between these factors and the development of ectopic firing. Methods Canine lumbar dorsal roots with dorsal root ganglia were immersed in an oxygenated artificial cerebrospinal fluid, and activity of the nerve root was recorded using bipolar platinum electrodes. Using this model, the effects of quantitative mechanical compression and hypoxia on the ectopic firing were analyzed. Results When compression was applied, mechanical thresholds for eliciting firing were much lower in dorsal root ganglia than in dorsal roots, and the firing lasted for a longer period in dorsal root ganglia. Under hypoxia, dorsal root ganglia showed firing, and their thresholds from mechanical stimuli decreased significantly. In dorsal roots, impulse propagation was not affected, whereas firing was seen under the hypoxic condition. Conclusion Dorsal root ganglia are highly sensitive to mechanical compression and hypoxia and closely related to abnormal sensations and pain in radiculopathy.

Problems with repeated arthroscopic surgery in the discoid meniscus

To identify the main causes of repeated arthroscopic surgery of the knee joint and to find out the points of therapeutic approaches, we evaluated 139 patients who underwent arthroscopic meniscectomy in our department and in affiliated hospitals between 1983 and 1987. Two or more arthroscopic surgeries were needed in 9 knees of 8 patients (6.5%). In 5 knees with no known injuries, the primary reason for repeated surgery was horizontal tears of remnant meniscus after partial resection of lateral discoid meniscus. The most appropriate initial treatment for lateral discoid menisci in cases without tear should be observation of the clinical course with minimal treatment using diagnostic arthroscopy.

Compression of the Suprascapular Nerve by a Ganglion at the Suprascapular Notch

The suprascapular nerve was compressed by a ganglion in the suprascapular notch in a 28-year-old carpenter. Electromyogram studies, especially mean latency time, were essential for accurate diagnosis. Excision of the ganglion relieved the pain and led to recovery of the motor function of the shoulder.

The action of prostaglandin E2 and triamcinolone acetonide on the firing activity of lumbar nerve roots

Summary. Sciatica, due to lumbar disc herniation, is understood electrophysiogically to be an ectopic firing originating from a nerve root. The recent concept of chemical radiculitis implies the involvement, not only of mechanical compression, but also of chemical mediators which contribute to the generation of ectopic firing. The present study demonstrates that prostaglandin E 2, a chemical mediator of inflammation, provoked the ectopic firing of nerve roots in a canine in vitro model which indicates that it may play a part in the irritation of nerve roots. In contrast, triamcinolone acetonide suppressed the firing induced by prostaglandin suggesting that steroids may be effective in the treatment of root symptoms.Résumé. Une sensation anormale, telle qu’une névralgie sciatique provoquée par la formation d’une hernie discale lombaire, est électrophysiologiquement comprise comme un déclenchement ectopique provenant de la racine du nerf. Une étude récente admet le concept de »radiculite chimique«, ce qui signifie non seulement une compression mécanique mais aussi des médiateurs chimiques ou neuromédiateurs qui contribuent à la génération d’un déclenchement ectopique. L’étude actuelle démontre que la prostaglandine E 2, un médiateur existant avec l’inflammation, est susceptible de provoquer un déclenchement ectopique de la racine du nerf en utilisant un modèle canin in vitro. Ceci permet de suggérer que la prostaglandine E2 joue un rôle dans l’irritation de la racine du nerf. D’autre part, la triamcinolone supprime le déclenchement provoqué par la prostaglandine E2, ce qui indique une efficacité clinique du stéroïde pour le traitement de symtômes radiculaires.

Trigger Wrist Caused by a Giant Cell Tumour of Tendon Sheath

Trigger wrist is a rare condition unlike the trigger finger of the metacarpophalangeal joint. This report describes a case of trigger wrist secondary to a giant cell tumour of the flexor tendon sheath. No previous reports are available in the medical literature.

Prevention of postoperative nail deformity after subungual glomus resection

Glomus tumors arise from the subcutaneous glomus body, which is an arteriovenous anastomosis involved in the regulation of cutaneous blood circulation. Complete removal of the tumor is required for treatment. However, some reports mention recurrence of the tumor, and postoperative nail deformity in subungual cases has also been reported. Cases of histologically diagnosed glomus tumors are reviewed, and a technique to prevent postoperative nail deformity is introduced.

Free Vascularised Bone Grafts in Reconstruction of the Upper Extremity

Free vascularised bone grafting was performed on six patients with large segmental bone defects following trauma, osteo-cutaneous defects and large bony defects following tumour resection. A free vascularised fibular graft was performed in five patients and a free iliac osteo-cutaneous flap was performed in one patient. In all patients, bony fusion was achieved by two to three months, without infection or recurrence of bone tumour. The donor site deficit was minimal.

Extensor tendon rupture after osteoarthrosis of the wrist associated with nonrheumatoid positive ulnar variance.

Rupture of the extensor tendon after osteoarthrosis of the wrist associated with nonrheumatoid, positive ulnar variance is uncommon. Eight cases were seen in the last five years. They included five men and three women, whose ages ranged from 54 to 82 years (average, 70 years). In all the cases, roentgenograms revealed osteoarthrotic changes in the wrist and dorsal subluxation or dislocation of the ulnar heads. Seven cases had operations. Friction with the dorsally subluxated or dislocated ulnar head and the osteophytes surrounding it caused these tendons to rupture. It was impossible to use end-to-end sutures, so tendon transfers or tendon grafts were performed. The patients were evaluated one to four years after surgery. Three patients complained of some disability in their daily lives, notably, limited flexion of their fingers. It is important that during surgery the reconstructed tendons should not be strained excessively.

Automated spinal cord monitoring for spinal surgery

A microcomputer-based automated spinal cord monitoring system was developed and 56 spinal operations have been carried out with it since 1986. The system comprises an electrodiagnostic system (Dantec 2000M), an FM tape recorder, a channel selector, an electrical relay, a Modem and a microcomputer which controls all of the elements. The program allowed for automated recording and analysis of evoked potentials during spinal surgery and alarm signals were generated according to the criteria of amplitude decrease and latency delay. It was demonstrated that automated spinal cord monitoring in the operating room was performed easily, reliably and safely allowing the surgeon to react quickly to possible compromise of the spinal cord. The design and usefulness of the system is described in this report.

Palmaris Longus Transfer for Replacement of the First Dorsal Interosseous

Using palmaris longus, the first dorsal interosseous was reconstructed without free tendon graft. Palmaris longus prolonged with a strip of palmar fascia was transferred rectilinearly to the site of insertion of the first dorsal interosseous via a subcutaneous tunnel and fixed. This method was applied to seven hands of six patients and the follow-up observation continued for more than six months postoperatively. In six hands, favourable stability and abduction function of the index finger was achieved. In one hand, adhesion occurred at the site of the first dorsal interosseous muscle resulting in tenodesis. This operative method appears to be useful in the reconstruction of the first dorsal interosseous muscle from non-recovering paralysis following injury of the first dorsal interosseous muscle, or ulnar nerve. This method may also be utilized after decompression of chronic compression of the ulnar nerve giving no expectation of complete recovery by the reconstruction and augmentation of the first dorsal interosseous muscle. No unpleasant side effect was encountered.