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Experimental study of vascularized nerve graft: Evaluation of nerve regeneration using choline acetyltransferase activityMICROSURGERY, Issue 2 2001
Makoto Iwai M.D.
A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible. © 2001 Wiley-Liss, Inc. MICROSURGERY 24:43,51 2001 [source]
Management of Intraparotid Facial Nerve SchwannomasANZ JOURNAL OF SURGERY, Issue 10 2000
K. W. Chong
Background: The purpose of the present paper was to review the management of intraparotid facial nerve schwannoma so as to discuss its clinical presentation, evaluate the various possible diagnostic investigations, and compare the various surgical options and outcome. Methods: Case series was undertaken of five (1.3%) patients with facial nerve schwannoma out of 400 consecutive parotidectomies at Singapore General Hospital. Results: There were three men and two women with an age range of 29,65 years. Three patients presented with painless parotid lumps while two had painful parotid swellings. None had facial nerve paresis. Only one patient had preoperative diagnosis suspicious of schwannoma by fine-needle aspiration cytology (FNAC). Diagnoses were made intraoperatively. Four patients had excision with cable grafting of the nerve defect, achieving facial nerve grade II,IV (House,Brackmann scale). One patient who underwent enucleation of tumour with nerve preservation achieved grade II. Conclusions: Preoperative diagnosis is difficult but it is important for discussion of the extent and options of surgery. Fine-needle aspiration cytology holds promise in making a preoperative diagnosis. Enucleation with nerve preservation where possible seems to offer better facial function whereas nerve excision with cable graft can give satisfactory results. [source]
Secondary end-to-end repair of extensive facial nerve defects: Surgical technique and postoperative functional resultsHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2004
Hildegunde Piza-Katzer MD
Abstract Background. Repair of the transected facial nerve is imperative for restoration of muscle function, including the ability to produce appropriate facial expressions. Injury might involve the main trunk and its several branches. Restoration of function presupposes meticulous repair of all injured nerve branches. Methods. Here we report three cases of secondary tension-free end-to-end coaptation of a transected trunk and branches of the facial nerve by removal of the superficial part of the parotid gland. Results. Facial tone and symmetry at rest and motion were achieved. In two patients, a slight residual synkinesis is observed under stress. Conclusions. Direct end-to-end coaptation of the facial nerve and its branches by the technique described should be considered before deciding on grafts or rerouting procedures to deal with gaps of up to 15 mm. This technique is not recommended in the presence of infection and nerve defects. Intensive postoperative physiotherapy is required for optimal results. © 2004 Wiley Periodicals, Inc. Head Neck26: 770,777, 2004 [source]
Tissue engineering of peripheral nerves: Epineurial grafts with application of cultured Schwann cellsMICROSURGERY, Issue 1 2003
H. Fansa M.D., Ph.D.
After a simple nerve lesion, primary microsurgical suture is the treatment of choice. A nerve gap has to be bridged, with a nerve graft sacrificing a functioning nerve. Alternatively, tissue engineering of nerve grafts has become a subject of experimental research. It is evident that nerve regeneration requires not only an autologous, allogenous, or biodegradable scaffold, but additional interactions with regeneration-promoting Schwann cells. In this study, we compared epineurial and acellularized epineurial tubes with and without application of cultured Schwann cells as alternative grafts in a rat sciatic nerve model. Autologous nerve grafts served as controls. Evaluation was performed after 6 weeks; afterwards, sections of the graft and distal nerve were harvested for histological and morphometrical analysis. Compared to controls, all groups showed a significantly lower number of axons, less well-shaped remyelinizated axons, and a delay in clinical recovery (e.g., toe spread). The presented technique with application of Schwann cells into epineurial tubes did not offer any major advantages for nerve regeneration. Thus, in this applied model, neither the implantation of untreated nor the implantation of acellularized epineurial tubes with cultured Schwann cells to bridge nerve defects was capable of presenting a serious alternative to the present gold standard of conventional nerve grafts for bridging nerve defects in this model. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:72,77 2003 [source]