Ligament Reconstruction for Recurrent Anterior Dislocation of the Radial Head.

Isolated recurrent dislocation of the radial head (RH) is very rare, and there have been few reports describing the surgical treatment of this injury. We herein report the case of a 13-year-old girl who underwent ligament reconstruction surgery for isolated recurrent RH dislocation. Her symptoms included pain and apprehension at the elbow with the forearm in supination. A radiologic examination revealed anterior dislocation of the RH with the forearm in supination but complete reduction with the forearm in neutral to pronated positions. Surgical treatment to reconstruct the annular ligament and facilitate the radial collateral ligament was performed using an autograft with internal brace augmentation. At a 12-month follow-up examination, the patient had asymptomatic stability with recovery to sports activities. This case report describes a novel technique for the treatment of a rare pathological condition of the elbow.

Radial nerve palsy at the elbow.

We studied the clinical features and images along with surgical findings of 8 cases of radial nerve palsy due to a space-occupying lesion (SOL) at the elbow. Based on image findings, we examined compressing masses and their extent, we contrasted them with operative findings of the radial nerve, and we surmised the site of impairment. Compressing masses were ganglions in 6 cases, an old radial head dislocation in 1 case, and engorged radial recurrent vessels in 1 case. The extent of the SOLs was roughly 15-40 mm from the interepicondylar line and 0-30 mm from the radiohumeral joint. In operative findings, only the posterior interosseous nerve (PIN) was compressed in 5 cases, while both the PIN and superficial branch were compressed in 3 cases. No apparent correlation between operative findings and the type of palsy was found. The radial tunnel has yet to be defined clearly, but the radial nerve palsy is readily understandable in cases of SOLs via the definition of the radial tunnel as the tubular structure from the radiohumeral joint to the outlet of the supinator muscle.

Gait characteristics of sciatic nerve palsy--a report of four cases.

There are few reports concerning the gait characteristics of sciatic nerve palsy. Four cases, one with complete palsy and three with incomplete palsy, are presented. Complete palsy (case 1) was due to sacrifice of the sciatic nerve in a wide excision for chondrosarcoma in the left ischium. Incomplete palsy (cases 2, 3, and 4) was due to contusion incurred in traffic accidents. It is noteworthy that all four patients could walk with or without a short-leg brace. But the patients with complete loss of proprioception distal to the ankle (cases 1 and 2) had to watch their steps while walking to maintain their walking balance. This clinical analysis revealed that proprioceptive impairment of the sciatic nerve caused a walking disability even though the palsy was incomplete.

Field distribution of compound muscle action potentials of the calf muscles in rabbits.

The purpose of this study is to verify that compound muscle action potentials (CMAPs) generated a stationary potential and to examine extension of the CMAPs away from the stimulated muscle. A referential derivation and/or bipolar derivation to record the stationary potentials were carried out following tibial nerve stimulation at the popliteal fossa in 10 rabbits. After recording a bipolar and/or referential derivation, wave changes were monitored before and after severing the tibial nerve. The change of the wave by compressing or direct electrical stimulation to the calf muscle was also monitored. In referential derivatives, the stationary waves were observed on top of the skull in all the rabbits examined with the peak latency of the potentials from 3.78 msec to 5.04 msec. In bipolar derivations, the upper limits of the stationary waves recorded were the trunks. The peak latencies were from 2.35 msec to 5.46 msec with an average of 4.12 msec. By analyzing the results from severing the tibial nerves, compressing the calf muscles, and direct electrical stimulation of the calf muscle, the origin of these stationary potentials was determined to be CMAPs of the calf muscles. These findings suggest contamination of the stationary potentials originated by CMAPs for recording of any evoked potentials when motor nerves are stimulated.

Clinical results in severe carpal tunnel syndrome and motor nerve conduction studies.

The purposes of this study were to assess the value of motor nerve conduction studies as a prognostic indicator for severe carpal tunnel syndrome (CTS) and to investigate residual nerve disorder after surgery. Fifty hands in 46 patients with severe CTS were followed for at least 6 months after surgery for open carpal tunnel release. Compound muscle action potential (CMAP) from the abductor pollicis brevis (APB) muscle and the second lumbrical (SL) muscle were recorded before and after surgery, and distal latency (DL) and amplitude were analyzed. APB-CMAP was not recordable in 43 hands while SL-CMAP was recordable in all 50 hands before surgery. Results were excellent in 28 hands, good in 16 hands, fair in 6 hands, with no poor results after surgery. The ratio of excellent result was 65% in patients in whom DL of preoperative SL-CMAP was less than 10 ms, and 20% in patients whose DL was 10 ms or more. Delayed DL was seen in postoperative APB-CMAP and SL-CMAP, especially in the patients with good or fair results. We consider that SL-CMAP was valuable as a prognostic indicator for severe CTS, and if DL was 10 ms or more, myelinization of fibers would not be sufficient after surgery.