Intellectual and scientific content of the study. ABSTRACT PURPOSE:To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats. METHODS:Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12.Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test. RESULTS:Exposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation. CONCLUSION:Intraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.

The purpose of this article is to describe a case of an 8-month-old girl who was diagnosed with a melanotic neuroectodermal tumor and was submitted to a right hemimandibulectomy and immediate reconstruction with a fibular osteocutaneous free flap. At 12-year follow-up, the longest reported in a patient this young, the transferred bone had grown much like the native mandible, and the patient had adequate mandibular contour and function. No revisions were needed, although orthopedic surgery was performed to correct an ankle valgus deviation on the donor leg. It is the opinion of the authors that microsurgical mandible reconstruction in very young patients is efficient and that the surrounding structures contribute to the remodeling of the bone segment to achieve characteristics similar to those of the native mandible.

The fibrin conduit could be used for nerve reconstruction following peripheral nerve injury in the rat model. However, the functional recovery in the fibrin conduit repair group was worse than that in nerve autograft group and the nerve repair with the fibrin conduit has less myelinated fibers when compared to the repair with nerve autograft.

PURPOSE:To compare sciatic nerve regeneration in rats using three different techniques of repair. METHODS:Fifteen isogonics rats were divided into three groups according to the method used to repair a 5-mm long defect created in the sciatic nerve: autogenous graft (Group A), polyglycolic acid tube (PGAt) (Group B), and of the association of PGAt with the graft (Group C). Histological analysis, regenerated myelinated axon number count and functional analysis were used to compare after six weeks. RESULTS:There was no difference in fiber diameter and degree of myelinization presented by Groups A, B and C. Group B presented the lowest number of regenerated axons. The groups did not display any significant functional difference after walking track analysis (p<0.05). CONCLUSION:No differences between the three groups in terms of functional recovery, although there were histological differences among them.

Introduction: Muscle contraction generated by electrical impulses simultaneously originating from two different neural sources may be an interesting treatment alternative for long term facial palsy. An experimental model was designed to compare single and dual innervation of the gastrocnemius muscle (GM) in rats.Methods: Fifty adult Wistar rats underwent transection of their right peroneal nerve and were divided into five groups (n = 10): control (C), tibial nerve section (TS), tibial nerve primary end-toend neurorrhaphy (PEE), tibial nerve primary repair associated with end-to-side peroneal-to-tibial nerve transfer (PRES), and tibial nerve repair by convergent end-to-end (CEE) neurorrhaphy between the proximal stumps of the tibial and peroneal nerves to the distal stump of the tibial nerve. The outcomes were assessed 12 weeks after the experiment by walking track, electromyography, GM mass index, and histomorphometric analysis of the distal tibial nerve. Results:The functional recovery of the PRES (−33.77 ± 24.13) and CEE (−42.15 ± 31.14) groups was greater (P < 0.003) than the PEE group (−80.26 ± 17.20). The CEE group (18.35 ± 7.84) showed greater amplitude (P = 0.006) than the PEE group (8.2 ± 4.64). There was no difference in the muscle mass index among the reinnervation groups (P > 0.705). Histologic analysis revealed greater (P < 0.002) axonal density in the CEE group (126.70 ± 15.01) compared to PEE (99.70 ± 12.82) and PRES (92.00 ± 19.17) groups. Conclusions:The dual innervation techniques showed earlier and greater functional recovery of the GM than did the single innervation technique. The CEE group showed a 40% higher number of regenerated axons in the distal tibial nerve stump.

The vertical suture of the rectus abdominis sheaths was stronger than the horizontal suture because of the more transversal arrangement of its aponeurotic fibers. Thus, routine use of the vertical suture in plications of the aponeurosis of the rectus abdominis muscles is suggested.

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