Convergent end-to-end neurorrhaphy: An alternative technique for dual innervation of the gastrocnemius muscle in rats.

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-to-end 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.

Mandibular reconstruction with a fibular osteocutaneous free flap in an 8-month-old girl with a 12-year follow-up.

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.

Biomechanical analysis of sutures used for mesh fixation in the donor area after removal of the rectus abdominis muscle.

BACKGROUND: The use of synthetic mesh for abdominal wall closure after removal of the rectus abdominis is established but not standardised. This study compares two forms of mesh fixation: a simple suture, which fixes the mesh to the edges of the defect on the anterior rectus abdominis fascia; and total fixation, which incorporates the fasciae of the internal oblique, external oblique and transverse muscles in the suture, anchoring the mesh in the position of the removed muscle. METHOD: A total of 16 fresh cadavers were dissected. Two sutures were compared: simple and total. Three different sites were analysed: 5 cm above, 5 cm below and at the level of the umbilicus. The two sutures compared were tested in each region using a standardised technique. All sutures were performed with nylon 0, perpendicular to the linea alba. Each suture was secured to a dynamometer, which was pulled perpendicularly towards the midline until the rupture of the aponeurosis. 'Rupture resistance' was measured in kilogram force. The mean among the groups was compared using the paired Student's t-test to a significance level of 1% (p<0.01). RESULTS: The mean rupture resistance of the total suture was 160% higher than that of the simple suture. CONCLUSION: The total suture includes the external oblique, internal oblique and transverse fasciae, which are multi-directional, and creates a much higher resistance when compared with the simple suture. Total suture may reduce the incidence of bulging and hernias of the abdominal wall after harvesting the rectus abdominis muscle, but comparative clinical studies are necessary.