Kenji Kimori

The Diagnostic Value of MRI in Traumatic Brachial Plexus Injury

Findings in 34 patients with traumatic brachial plexus injury documented by surgical exploration and intra-operative somatosensory-evoked potentials were correlated with findings on myelography and magnetic resonance imaging (MRI) to determine whether MRI can identify nerve root avulsion. The coronal and sagittal planes were not able to demonstrate avulsion of the individual nerve roots. The axial and axial oblique planes did provide useful information to determine which nerve root was avulsed in the upper plexus, although it was difficult to clearly delineate the lower cervical rootlets. The accuracy of MRI was 73% for C5 and 64% for C6 and that of myelograpby 63% for C5 and 64% for C6. Thus, the diagnostic accuracy of MRI for upper nerve roots was slightly superior to myelography. Although its primary diagnostic value is limited to the upper nerve roots whose avulsion is relatively difficult to diagnose by myelography, MRI can provide useful guidance in the waiting period prior to surgical exploration after brachial plexus injury.

TREATMENT OF SUBUNGUAL GLOMUS TUMOUR

We reviewed 30 patients with subungual glomus tumours of the hand operated on between 1964 and 1997. Seven patients were male and 23 were female. Their age ranged from 16 to 78 years. A transungual approach was selected in 27 patients, and a periungual approach in three. Pre-operative pain subsided in all of the patients, but recurrence of the pain was observed in nine. Nail deformities were observed in nine patients before surgery. After surgery, it disappeared in three patients, persisted in six, and new deformities developed in five. To avoid recurrence of pain, it is important that the accurate pre-operative localisation of the tumour and a complete extirpation should be performed. To avoid nail deformity, it is better to apply a periungual approach for tumours developing in the peripheral region, and a transungual approach followed by meticulous repair of the nail bed for tumours developing in the central region.

FREE VASCULARIZED TOE JOINT TRANSFER TO THE HAND. A TECHNIQUE FOR SIMULTANEOUS RECONSTRUCTION OF THE SOFT TISSUE

Twelve patients underwent reconstruction of injured finger joints using our technique of a vascularized transfer of the second toe proximal interphalangeal joint. The age of the patients at operation ranged from 7 to 47 years and the postoperative follow-up was 9 to 48 months. All the joint transfers survived and united with resolution of the preoperative joint pain, deformity and instability. The average range of motion of the reconstructed joints was 59° in the proximal interphalangeal and 54° in the metacarpophalangeal joints. No patient complained of pain or functional deficits in the donor foot.

Delay of the denervation process in skeletal muscle by sensory ganglion graft and its clinical application

&NA; We examined the effects of dorsal root ganglion isografts on the denervation process of skeletal muscle. A segment of sciatic nerve was removed from each of 25 inbred Wistar‐Kyoto rats. Fifteen were set aside as controls. In the remaining 10 rats, isogeneic cervical dorsal root ganglia were grafted to the severed distal stump of the common peroneal nerve. Between day 72 and day 286 postoperatively, both controls and recipients were killed after twitch and tetanic tension recording of the extensor digitorum longus was performed. The wet muscle weight and the twitch and tetanic tensions of the denervated extensor digitorum longus in the graft group were significantly greater than those in the control group. The mean area of the denervated tibialis anterior muscle fibers in the graft group also was significantly larger than that in the control group. In electron and light microscopic images, nerve cells along the periphery of each dorsal root ganglion were found surviving with regenerating axons throughout the experimental period. Numerous myelinated axons were observed in the common peroneal nerve of the graft group, and there were significantly more axonal branches in the extensor digitorum longus of the graft group than in the extensor digitorum longus of the control group. Thus sensory nerve fibers from the grafted dorsal root ganglia had certain beneficial effects to slow the denervation process, presumably secreting trophic factors into the denervated muscle. Clinically, we have transferred avulsed dorsal root ganglia in cases of total brachial plexus avulsion directly into denervated skeletal muscle. This procedure, accompanied by nerve crossing procedures, will probably keep denervated skeletal muscle in a better condition until regenerating motor axons from the repair site reach their target muscle.

Reinnervation of denervated skeletal muscles by grafted dorsal root ganglion

We examined whether or not the cervical dorsal root ganglion (DRG) of the rat, when isografted and connected to the distal stump of the severed common peroneal nerve, could survive, project axons to the denervated leg muscles, and exert beneficial influences to delay the degeneration of the denervated muscles. Rats in which the muscles were similarly denervated but no DRG was grafted served as the control. After a postoperative period of 72 to 286 days, histological study showed that nerve cells at the superficial part of the grafted DRG survived. Indirect electrical stimulation via the distal stump of the common peroneal nerve produced no contraction of the muscles, indicating that no functional neuromuscular contacts had been reestablished. Direct stimulation of the denervated muscles did elicit contraction, and the isometric twitch and tetanic tensions were significantly much higher in the experimental rats with a grafted DRG than in the control rats. Cholinesterase-silver staining indicated the presence of axons in the denervated muscles, but the axons did not terminate on endplates. Compared with the control muscles, the experimental muscles had significantly more axons, and had atrophied less as indicated by muscle wet weight and histological appearance. These results indicate that the sensory axons can delay the weakening and atrophy of muscles after denervation. We suggest that the sensory axons may exert certain trophic influence on the denervated muscle fibers, though the actual mechanism is unknown.

Double-toe transplantation following temporary insertion of a block of silicone for reconstruction of a traumatic metacarpal defect.

The treatment of the mutilated hand with more than one digit missing and a metacarpal defect is challenging. We used double-toe transfer after temporary insertion of a block of silicone to fill the bony defect.

MRI Analysis of Carpal Tunnel Syndrome Hemodialysis Patients, Compared With Nonhemodialysis Patients

Objective: Carpal tunnel syndrome (CTS) is common among patients receiving hemodialysis and deeply influences the daily life. Amyloid deposits are considered as the main reason for median nerve compression but the prevalence is unclear. In this study, to determine the main region of amyloid deposit inside carpal tunnel, we measured cross-sectional area (CSA) of each composition of carpal tunnel in preoperative MRI. Materials and Methods: In all, 41 hemodialysis patients (HD) and age, sex-matched 41 nonhemodialysis patients (NHD), who underwent the first surgery for CTS in Tsuchiya General Hospital (Hiroshima, Japan) from 2005 to 2015, were retrospectively collected. CTS was diagnosed from clinical and electromyographic (EMG) findings. CSA of carpal tunnel, each flexor tendon and median nerve at the level of hook of hamate, were measured in T1-weighted axial image in preoperative MRI, by using Synapse OP-A software. Statistical analysis was performed by student’s t test and Pearson’s chi-square test. This study was approved by institutional review board. Results: HD was 64.3 years and the dialysis duration was 21.9 (11-35) years, and NHD was 65.5 years. CSA of carpal tunnel (HD: 204.2 mm2, NHD: 191.3 mm2, P = .01), flexor tendon (HD: 101.2 mm2, NHD: 92.7 mm2, P = .03), and flexor digitorum profundus tendon (FDP; HD: 57.3 mm2, NHD: 49.8 mm2, P = .04) were bigger in HD group, but median nerve, flexor digitorum superficialis tendon, and flexor pollicis longus tendon were not significantly different from NHD group. Dialysis duration or age to each CSA did not show any strong correlation. In one dialysis patient, accessory tendon of FDP was dissected during the surgery to reduce the pressure of carpal tunnel, and then it was histologically analyzed. Amyloid deposition was confirmed not only around but inside the tendon itself by Dylon stain. Conclusions: We identified hemodialysis caused CSA expansion of carpal tunnel due to amyloid deposition as previously described. Also CSA expansion of flexor tendon, especially FDP, was happened, possibly because amyloid deposited not only around but inside the tendon. We could not identify why it happened to FDP mostly from this study. Great progress had been made on the technique of Beta 2-microglobulin removal in these years, and it is a possible reason why we could not find any correlation between duration of hemodialysis or age to any CSA.