Evaluation of the Use of Nerve Allograft Preserved in Glycerol.

BACKGROUND: We aimed to evaluate the use of nerve allograft preserved in glycerol. We compared the efficiency of glycerol-preserved allografts with autogenous nerve grafting, cryopreserved grafts, and detergent-processed grafts in the axonal regeneration. Secondarily, we evaluated the effectiveness of each preservation method in maintaining the extracellular matrix free of cellular components. METHODS: This was a prospective experimental, longitudinal, unblinded, nonrandomized, controlled animal model study. Three different allograft preservation techniques for the repair of sciatic nerve injuries were compared, including cold preservation, glycerol preservation, and detergent preservation. Functional assessment was performed, and histomorphometric analyses were further performed, which enabled the allograft structure evaluation and an estimation of the nerve regeneration efficacy based on the myelinated axons count and on their diameters. RESULTS: After the 14th week, all groups were already balanced and similar (P = 0.265): all groups present near-zero SFIs, thus confirming their efficiency in promoting nerve regeneration. In the histomorphometric evaluations, all groups were equivalent, presenting a similar efficiency in nerve regeneration (P = 0.716 and P = 0.577, respectively). Similarly, histomorphometric evaluations showed a reduction in the number of axons and in their diameters, but none of them effectively eliminated all cellular debris. Comparing the groups with each other, the groups preserved in glycerol and detergent solution were similar, both presenting better results than the cooled group. CONCLUSION: By evaluating the presence of cell debris after the treatment using glycerol, it was found to be similar to the treatment using detergent and significantly better than the cold-preservation treatment.

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.

Chimerical anterolateral thigh flap for plantar reconstruction.

OBJECTIVE: The purpose of this study is to evaluate the results of reconstruction and rehabilitation of patients with plantar defects by using a chimerical flap of muscle and skin from anterolateral thigh. METHODS: Twenty-five patients with plantar defects were reconstructed with a chimerical anterolateral thigh (ALT) flap, composed by a vastus lateralis muscle segment and a thinned skin island. Neurorrhaphy between lateral femoral cutaneous nerve and calcaneal nerve was performed in 7 patients. Evaluation of flap contour and stability and patient ambulation was performed 6 and 12 months after surgery. Evaluation of cutaneous sensiblity of ALT flap and contralateral thigh was performed 12 months after surgery using Pressure Specified Sensory Device™ (PSSD™). RESULTS: Flap viability was complete in 23 patients and 2 patients had complications with partial flap loss of its cutaneous component. Six months postoperatively, flap contour, and stability was considered good in 19 and 21 patients respectively, and all 25 patients presented good ambulation. Twelve months postoperatively, all 25 patients presented good flap contour and stability, as well as good ambulation. All 7 flaps undergoing to reinnervation partially recovered cutaneous sensibility in comparison to donor site (contralateral thigh). Cutaneous tactile thresholds (g/mm(2) ) of static one-point test and moving one-point test from the ALT flap and the contralateral thigh presented statistically significant differences, for both comparisons (P = 0.009, P = 0.002). CONCLUSION: This flap is suitable for reconstruction of plantar defects, with good flap contour and stability, proper patient ambulation and low complication rates.

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.

A clinical experience of the supraclavicular flap used to reconstruct head and neck defects in late-stage cancer patients.

The supraclavicular island flap has been widely used in head and neck reconstruction, providing an alternative to the traditional techniques like regional or free flaps, mainly because of its thin skin island tissue and reliable vascularity. Head and neck patients who require large reconstructions usually present poor clinical and healing conditions. An early experience using this flap for late-stage head and neck tumour treatment is reported. Forty-seven supraclavicular artery flaps were used to treat head and neck oncologic defects after cutaneous, intraoral and pharyngeal tumour resections. Dissection time, complications, donor and reconstructed area outcomes were assessed. The mean time for harvesting the flaps was 50 min by the senior author. All donor sites were closed primarily. Three cases of laryngopharyngectomy reconstruction developed a small controlled (salivary) leak that was resolved with conservative measures. Small or no strictures were detected on radiologic swallowing examinations and all patients regained normal swallowing function. Five patients developed donor site dehiscence. These wounds were treated with regular dressing until healing was complete. There were four distal flap necroses in this series. These necroses were debrided and closed primarily. The supraclavicular flap is pliable for head and neck oncologic reconstruction in late-stage patients. High-risk patients and modified radical neck dissection are not contraindications for its use. The absence of the need to isolate the pedicle offers quick and reliable harvesting. The arc of rotation on the base of the neck provides adequate length for pharyngeal, oral lining and to reconstruct the middle and superior third of the face.