A functional model of nerve repair. Reanastomosis vs entubulation repair.

OBJECTIVE: To compare reanastomosis and entubulation repair after transection of the peroneal nerve in rats with the use of 2 functional models: gait analysis and a tension transduction device. DESIGN: Prospective, randomized, blinded control study. Each animal served as its own control. The injured site was alternated between the left and the right. Gait analysis was evaluated in a blind fashion at postoperative weeks 1, 3, 7, and 13, and the tension transduction device at week 13, for injured and uninjured legs. SUBJECTS: Animals underwent unilateral peroneal nerve transection injury, half with entubulation and half with end-to-end reanastomosis repair. INTERVENTION: Nerve transection was performed 6 mm proximal to the anterior tibialis muscle insertion followed by reanastomosis (epineurial suture placement to align the sectioned nerve ends) or entubulation (placement of nerve ends into a 4-mm-long sterile Silastic tube secured with 2 epineurial sutures). RESULTS: Gait analysis demonstrated a poorer ankle angle in all injured legs compared with uninjured legs at each postoperative period. Ankle angles for reanastomosis were statistically better than those for entubulation at weeks 3, 7, and 13. The tension transduction device demonstrated poorer force in injured than uninjured animals at 13 weeks. Reanastomosis repair groups demonstrated no difference in force development compared with entubulation repair groups. CONCLUSIONS: Reanastomosis of the transected rat peroneal nerve demonstrated improved functional return by gait analysis when compared with entubulation-repaired nerves at postoperative weeks 3, 7, and 13. Force development of injured nerve groups measured by the tension transduction device was decreased compared with control, but no difference was detected between the 2 repair methods. Further studies are needed to evaluate the possible functional benefit of reanastomosis.

Hyperbaric oxygen treatment after rat peroneal nerve transection and entubulation.

Rat peroneal nerves were transected and entubulated with a Silastic channel. The experimental group was treated with hyperbaric oxygen to evaluate changes in acute edema, functional recovery, and histology. Hyperbaric oxygen was administered with 100% O2 at 2.5 atmospheres absolute for 90 minutes twice a day for 1 week and then four times a day for 1 week. Acute edema changes based on nerve water weight and transfascicular area measurements were greater in injured than in uninjured nerves but demonstrated no differences between hyperbaric oxygen-treated and -untreated groups 2, 8 and 16 days after surgery. Functional evaluation with gait analysis demonstrated significant changes between injured and uninjured group 1, 3, 7, and 13 weeks after injury but no differences between hyperbaric oxygen-treated and -untreated groups. Thirteen weeks after the initial injury, elicited muscle force measurements demonstrated no significant improvement from hyperbaric oxygen treatment of injured nerves. Histologic evaluation of nerve area, myelinated axon number, myelinated axon area, myelin thickness, and blood vessel number and area revealed no significant differences between hyperbaric oxygen-treated and -untreated groups. Hyperbaric oxygen was not associated with improvement of nerve regeneration with any of the outcome variables in this model.

Dietary lipid requirements of adult lobsters, Homarus americanus (M.E.).

The effects of several dietary lipids on adult American lobster (Homarus americanus) were assessed over a 10 month feeding period. Cod liver oil (CLO) resulted in greater precent weight gains, feed conversion, percent edible meat and higher serum protein and hemocyte counts than either corn oil (CO) or hydrogenated coconut oil (HCO). These differences were probably due to an essential fatty acid (EFA) requirement by the lobster for linolenic series omega3 or other fatty acids present in CLO. The linoleic or omega6 fatty acids of CO appeared to have some sparing effect on several of the EFA deficiency symptoms. It was found that 5% CLO was optimal for mean percent weight gain, molt incidence, feed conversion and hemocyte counts of lobsters. Further increases in dietary CLO to 10% and 15% resulted in no significant improvement of any of the condition indices used. There was a decrease in serum protein and calcium when lobsters were fed a non-saponifiable sterol deficient diet. The addition of 1% cholesterol to the diet raised the serum protein, but resulted in even a greater decrease in the serum calcium level.