Viktor E. Meyer

Functional and morphometric evaluation of end-to-side neurorrhaphy for muscle reinnervation.

This study was undertaken to quantify the effect of motor collateral sprouting in an end-to-side repair model allowing end organ contact. Besides documentation of the functional outcome of muscle reinnervation by end-to-side neurorrhaphy, this experimental work was performed to determine possible downgrading effects to the donor nerve at end organ level. In 24 female New Zealand White rabbits, the motor nerve branch to the rectus femoris muscle of the right hindlimb was dissected, cut, and sutured end-to-side to the motor branch to the vastus medialis muscle after creating an epineural window. The 24 rabbits were divided into two groups of 12 each, with the second group receiving additional crush injury of the vastus branch. After a period of 8 months, maximum tetanic tension in the reinnervated rectus femoris and the vastus medialis muscles was determined. The contralateral healthy side served as control. The reinnervated rectus femoris muscle showed an average maximum tetanic force of 24.9 N (control 26.2 N, p = 0.7827), and the donor vastus medialis muscle 11.0 N (control 7.3 N, p = 0.0223). There were no statistically significant differences between the two experimental groups (p = 0.9914). The average number of regenerated myelinated nerve fibers in the rectus femoris motor branch was 1185 ± 342 (control, 806 ± 166), and the mean diameter was 4.6 ± 0.6 &mgr;m (control, 9.4 ± 1.0 &mgr;m). In the motor branch to the vastus medialis muscle, the mean fiber number proximal to the coaptation site was 1227 (±441), and decreased distal to the coaptation site to 795 (±270). The average difference of axon counts in the donor nerve proximal to distal regarding the repair site was 483.7 ± 264.2. In the contralateral motor branch to the vastus medialis muscle, 540 (±175) myelinated nerve fibers were counted. In nearly all cross-section specimens of the motor branch to the vastus medialis muscle, altered nerve fibers could be identified in one fascicle distal and proximal to the repair site. The results show a relevant functional reinnervation by end-to-side neurorrhaphy without functional impairment of the donor muscle. It seems to be evident that most axons in the attached segment were derived from collateral sprouts. Nonetheless, the present study confirms that end-to-side neurorrhaphy is a reliable method of reconstruction for damaged nerves, which should be applied clinically in a more extended manner. (Plast. Reconstr. Surg. 106: 383, 2000.)

Soft Tissue Infections of the Upper Extremities with Special Consideration of Abscesses in Parenteral Drug Abusers: A prospective study

Despite surgical advances and new antibiotics, upper extremity infections continue to present a serious problem. Soft tissue infections of the upper extremities were prospectively examined to elucidate incidence, cause, bacterial pathogens involved, and treatment. Special attention was paid to infections associated with parenteral drug abuse. During an 18-month period all patients over 16 years of age presenting for treatment of an established infection were included in the study. Conservative treatment consisted of immobilization and antibiotics. Radical débridement with removal of all necrotic tissue was the guideline for operative care. In addition, for both regimens a penicillinase-resistant antibiotic was administered. A total of 415 patients (271 men and 144 women; mean age 36.7 ± 14.5 years) were enrolled into the study, 55 of whom were parenteral drug abusers; 45 of these were HIV-reactive. Infections of fingers (excluding paronychia), paronychia, and abscesses at injection sites were the most common diagnoses. Operative and conservative treatment were performed in 285 and 130 patients respectively. Staphylococcus and streptococcus species were the predominant organisms recovered from 212 specimens of pus. Anaerobic bacteria and yeasts were of minor importance. Therefore, a penicillinase-resistant antibiotic is a good initial choice.

MRI of the Intrinsic Muscles of the Hand: Spectrum of Imaging Findings and Clinical Correlation

OBJECTIVE The purpose of our study was to describe the spectrum of intrinsic hand muscle abnormalities on MRI in patients with clinically evident abnormalities of the intrinsic hand muscles and to correlate clinical and radiologic findings. MATERIALS AND METHODS MRI of 21 hands was performed in 19 patients with clinically evident or suspected intrinsic hand muscle abnormalities. All MRI was performed on a 1.5-T scanner using transaxial T1-weighted, T2-weighted, or STIR as well as contrast-enhanced T1-weighted sequences. Two observers reviewed all MR images retrospectively in a blinded fashion with regard to the exact anatomic location of the muscle abnormality, signal abnormalities, muscle atrophy, and the cause. Kappa statistics were used to calculate interobserver variability. MRI findings were compared with clinical findings using Spearmans rank test. A panel of experts assessed the impact of MRI on the diagnostic workup. RESULTS On the basis of MRI findings, abnormalities (either MR signal abnormality or atrophy) of both the lumbrical and interosseus muscles were noted in 10 (48%) of 21 hands, of the thenar muscles in eight (38%) of 21 hands, and of the hypothenar muscles in 12 (57%) of 21 hands. The correlation between clinical and MRI findings was moderate to strong for the interosseus, thenar, and hypothenar muscles (0.43-0.84). MRI was judged to be useful for establishing the final diagnosis in 17 (81%) of 21 hands. CONCLUSION MRI of the hands is useful and correlates well with clinical findings in patients with intrinsic hand muscle abnormalities.

Use of vein loops in reconstructive procedures

The use of a temporary arteriovenous fistula prior to flap harvesting was suggested by Threlfall in 1982 (Threlfall, Aust NZ J Surg 52: 182–184, 1982). The basic idea is to use long venous grafts that can be branched side‐to‐end to a main artery at an easily accessible level using one of the well‐established exposures from general vascular surgery. In reconstructive microsurgery, AV‐loops are used in limb salvage procedures and in cancer surgery. These patients have often undergone previous surgery and additional radiotherapy. AV‐loops facilitate the use of normal recipient vessels out of the zone of injury, or far away from scar or irradiated tissue.

The health technology assessment of the compulsory accident insurance scheme of hand transplantation in Switzerland

Recently the decision-making committee of the compulsory Swiss accident insurance scheme needed to make a basic decision as to whether to fund hand transplantation under that scheme or not. A Health Technology Assessment was commissioned to inform decision-making and gain experience with applicability of the method. The following were main findings from various domains. Compared with prosthesis fitting, the outcome of hand transplantation is satisfactory for function and sensibility. Complications due to immunosuppression are frequent, sometimes severe and potentially life-shortening. The direct medical costs over the entire life span calculated for a 35-year-old unilaterally amputated base case patient were CHF 528,600 (EUR 438,500) higher than for a prosthesis. There are challenging ethical, legal and organizational issues. The committee decided not to reimburse hand transplantation for ethical reasons. The Health Technology Assessment has been shown to be a useful tool for decision-making in the context of Swiss accident insurance. Level of evidence: IV