Vascularized nerve grafts for the treatment of large nerve gap after severe trauma to an upper extremity

We reviewed the clinical outcomes of vascularized nerve grafts for the repair of large nerve gaps (longer than 20 cm) after severe trauma to an upper extremity. Six patients who underwent vascularized sural nerve grafting (five to the median nerve and one to the ulnar nerve) with a monitoring skin flap were evaluated. The length of the vascularized sural nerve grafts ranged from 20 to 30 cm, with a mean length of 23.3 cm. All but one of the monitoring skin flap grafts was successful. In those patients for whom the monitoring skin flap graft was successful, the mean static-2PD at the corresponding fingertip was 14.2 mm (range 10–20 mm). Evaluation of these patients with the Semmes-Weinstein test produced the following results: filament 6, two patients; filament 10, three patients. The results of this study show that vascularized sural nerve grafting should be considered as a clinical alternative for nerve reconstruction in patients with nerve defects longer than 20 cm.     

Axonal regeneration rate through cross-face nerve grafts

The disfigurement of irreversible unilateral facial paralysis can be corrected by cross-face nerve grafting in conjunction with muscle transplantation. A total of 33 patients underwent cross-face nerve grafting using the sural nerve prior to undergoing the second stage of the procedure. Before a muscle transplant can be successfully connected to the distal end of the cross-face nerve graft, the regenerating axons need to have grown from the contralateral facial nerve to the distal end of the nerve graft. This can be tested by the Tinel sign. A retrospective study was performed to determine the rate of growth of regenerating axons through the cross-face nerve graft. A rate of axon growth of 1.8 mm/day was found, and also an inverse relationship between the age of the patient and the regeneration rate. These results can be used as a guide in planning patients' treatment. © 1993 Wiley-Liss Inc.     

A simplified atraumatic technique for tunneling a nerve graft in a cross-face nerve-grafting procedure

This report describes a simple and reliable method of tunneling a nerve graft in a cross-face nerve grafting procedure. In this technique, a subcutaneous tunnel is developed in two passes by means of a long hemostat that advances an 18F sterile tube from one side of the face to the other. The nerve graft is then attached to a heavy (1-0) polypropylene suture with a stitch that, by its inherent firmness, is easily threaded through the tube, dragging the nerve graft behind. Thus, the nerve graft can easily be delivered through the tube without any trauma. This technique has been used for seven patients without any complication. This is a simple and atraumatic technique for tunneling a nerve graft in a cross-face nerve grafting procedure.     

The blood supply of vascularized nerve grafts

The blood supply to 13 potential vascularized donor nerve grafts was examined by 241 cadaveric dissections. Results reveal a new classification of nerve blood supply that helps identify six of the 13 nerves as potential donor vascularized nerve grafts (anterior tibial, saphenous, superficial peroneal, superficial radial, ulnar, and sural nerves). These six nerves were then further investigated with injection studies, revealing that long lengths of the nerves may survive on the intrinsic supply alone. Extensive measurements were completed on the six nerves and corresponding blood supply. The surgical anatomy and clinical application of these donor nerves are reviewed. Each nerve was then evaluated in terms of new criteria developed for the ideal donor vascularized nerve graft. The saphenous nerve is believed to be best suited as a donor vascularized nerve graft. Finally, a new method is proposed for forming cable grafts from segments of vascularized nerve grafts that are supplied solely by the intrinsic blood supply.     

Comparison of regeneration across a vascularized versus conventional nerve graft: case report

A histological and functional comparison of regeneration across a vascularized and conventional nerve graft was carried out in a clinical case. The two branches of the medial antebrachial cutaneous nerve were used to neurotize the median nerve at the wrist. The superficial branch of the radial nerve (vascularized nerve graft) and a conventional sural nerve graft were used as the interposition grafts between the two branches of the medial antebrachial cutaneous nerve and the median nerve. This nerve grafting procedure was carried out in two stages. The proximal neurorrhaphy was carried out 7 months prior to the distal nerve repair. Biopsies were taken from the distal portions of the vascularized radial sensory nerve and the conventional sural nerve at the time of the second procedure. Histological evaluation demonstrated superior regeneration across the vascularized nerve graft. Subjectively, the patient described better sensory recovery in the territory innervated by the vascularized nerve graft. Sensory testing in the two territories demonstrated better sensibility in the territory innervated by the vascularized nerve graft.     

Baiting the cross-face nerve graft with temporary hypoglossal hookup

BACKGROUND: Cross-face nerve grafting yields inconsistent neural regeneration, and methods that promote more robust axonal traversing of the graft would expand the indications for this procedure. OBJECTIVE: To test the hypothesis that hooking a cross-face nerve graft distally to a source of denervated muscle, rather than leaving it in the subcutaneous space, would positively affect neural ingrowth across the graft, based on elaboration of neurotrophins from the musculature. METHODS: Twenty-four rats underwent cross-face nerve grafting in which the right facial nerve buccal branch was transected and coapted to the graft. The graft was placed across the neck and into the left side of the face. The distal end of the graft was placed either in the left subcutaneous space, coapted to the marginal mandibular branch of the left facial nerve, or coapted to the distal stump of the transected left hypoglossal nerve. Eight control animals underwent right buccal branch transection and placement of a cross-face nerve graft without any proximal and distal hookup. After 12 weeks, all experimental groups underwent hookup of the distal nerve graft to the left facial nerve buccal branch. Vibrissal function was assessed during the ensuing 12 weeks, and then the graft was harvested for histomorphometric analysis. RESULTS: After 12 weeks, there was a significant difference in axon counts between the group coapted distally to the tongue (hypoglossal hookup) and that coapted to the facial musculature (marginal hookup). Twelve weeks later, after distal cross-face nerve graft hookup, this difference was not statistically significant, although the hypoglossally baited group demonstrated statistically significantly greater fiber maturity. Recovery of vibrissal movement did not differ among treatment groups. CONCLUSION: Baiting the cross-face nerve graft via temporary hookup to the distal hypoglossal nerve and tongue musculature appears to improve nerve ingrowth through a nerve graft across the face, although a corresponding improvement in facial muscle function was not observed.     

比较两种带血供长段尺神经移植术神经再生远期结果的实验研究

目的 对带尺上副血管的尺移植和带尺侧上副血管加尺血管的尺神经移植中,神经再生的远期结果进行比较以供临床参考。方法 新西兰大白兔9只,将双侧上肢的尺神经游离后,于尺侧上副动脉起始水平及腕部切断后作原位移植。右侧：尺神经带尺侧上副血管。左侧：尺神经肘上带尺侧上副血管,肘下段则带尺血管。两侧尺神经原位移植后均置于屈肌群表面。术后7个月进行尺神经肌电、再箐髓纤维数与截面积、髓鞘（mt）和轴突／纤维的直径比（d／D）及肌肉组织学的检测。结果 术后7个月,9只大白兔双侧前足的溃疡均愈合。右侧尺神经移植段神经干的波幅、运动神经传导速度均低于左侧（P＞0．01）;而在腕部缝合口近端3cm水平,两侧再生有髓纤维数及截面积的差异均无显著性意义（P＞0．05）;而在腕部缝合口近端1cm、远端0．5cm水平,左侧优于右侧（P＜0．05,P＜0．01)。双侧小鱼际肌肌湿重及肌纤维截面积无明显差别。髓鞘厚度与d／D比值的差异无显著性意义。结论 两种带血供的尺神经移植术效果均好。再生神经纤维数量上的差异主要发生在移植神经远端部分。临床作带尺侧上副动脉的尺神经转位或移植时,应增加尺神经肘上段的长度,缩短肘下段的长度。     

New one-stage nerve pedicle grafting technique using the great auricular nerve for reconstruction of facial nerve defects

A new one-stage nerve pedicle grafting technique, employing a vascularized great auricular nerve graft, was used to repair a facial nerve defect. The facial nerve of a 39-year-old woman with facial schwannoma was resected, and an island vascularized great auricular nerve graft from the ipsilateral side was transferred to bridge a 4 cm long defect of the buccal branch. Postoperatively, rapid nerve sprouting through the vascularized nerve graft and excellent facial reanimation were obtained within 6 months after surgery. This method in one-stage using a vascularized nerve graft is technically easy, requires a short operating time, has minimal donor-site morbidity, and leads to successful nerve regeneration postoperatively.     

儿童腓肠神经营养血管逆行岛状皮瓣移植11例

目的 分析儿童腓肠神经营养血管皮瓣解剖及移植特点，比较小隐静脉结扎与否对皮瓣成活的影响。方法 11例儿童腓肠神经营养血管皮瓣移植修复足跟部皮肤缺损，其中3例术中结扎小隐静脉。皮瓣均成水滴状设计，开放外踝后方皮肤通道。结果 11例皮瓣均成活，5例术后皮瓣远端部分皮下组织液化。结论 腓肠神经营养血管皮瓣移植是治疗儿童足跟部皮肤缺损的有效方法。结扎小隐静脉对皮瓣成活无明显影响。切取皮瓣上界不超过小腿后部中上1/3处，两侧不超过侧中线；皮瓣成水滴状设计，开放外踝后方皮肤通道，及细致的显微外科操作，均是保证皮瓣移植成功的重要因素。     

逆行足内侧隐神经营养血管皮瓣修复足前部皮肤缺损

目的 探讨逆行足内侧隐神经营养血管皮瓣修复足前部皮肤缺损的方法.方法 2004年1月至2008年10月,采用逆行足内侧隐神经营养血管皮瓣修复足前部软组织缺损15例,皮瓣最大面积8 cm×5 cm,最小3.5 cm×3.0 cm.供区移植皮片覆盖.结果 术后所有皮瓣全部成活,10例获随访1～9个月,皮瓣色泽、质地、外形良好.患足行走正常,皮瓣及供区无溃疡发生.结论 应用逆行足内侧隐神经营养血管皮瓣修复足前部皮肤软组织缺损,血供可靠,操作简单,创伤小.     

Management of Facial Nerve in Surgical Treatment of Previously Untreated Fisch Class C Tympanojugular Paragangliomas: Long-Term Results

The aim of this study was to evaluate the long-term facial nerve outcome according to management of the facial nerve in patients undergoing surgery for Fisch class C tympanojugular paragangliomas. The study population consisted of 122 patients. The infratemporal type A approach was the most common surgical procedure. The facial nerve was left in place in 2 (1.6%) of the 122 patients, anteriorly rerouted in 97 (79.5%), anteriorly rerouted with segmental resection of the epineurium in 7 (5.7%), and sacrificed and reconstructed in 15 (12.3%). One patient underwent cross-face nerve grafting. At last follow-up, House-Brackmann grade I to II was achieved in 51.5% of patients who underwent anterior rerouting and in 28.5% of those who underwent anterior rerouting with resection of the epineurium. A House-Brackmann grade III was achieved in 73.3% of patients who underwent cable nerve graft interposition. The two patients in whom the facial nerve was left in place experienced grade I and grade III, respectively. The patient who underwent cross-face nerve grafting had grade III. Gross total resection was achieved in 105 cases (86%). Management of the facial nerve in tympanojugular paraganglioma surgery can be expected to ensure satisfactory facial function long-term outcome.     

Morphometric study of regeneration through vascularized nerve graft in a rabbit sciatic nerve model

Adequate vascularization is essential for a successful nerve graft. Theoretically, immediate vascularization will minimize fibroblast infiltration and support axonal regeneration. In this study, histomorphologic and morphometric studies were carried out to determine whether vascularized grafts are beneficial, in terms of axonal regeneration. In a rabbit model, 4-cm segments of sciatic nerve were obtained and placed as a nonvascularized graft on one side, and as a pedicled vascularized graft fed by the inferior gluteal vessel on the contralateral side. Histomorphologically, the distribution of myelinated nerve fibers and Schwann cells was evaluated after toluidine blue staining, at 2-, 3-, and 4-month intervals. The following results were obtained. 1) Myelinated nerve fibers were more abundant in the proximal, middle, and distal segments of the vascularized nerve group at 2 and 3 months. 2) The average nerve-fiber diameter was greater in the vascularized nerve graft group at 2, 3, and 4 months (2 to 10 microm). 3) Schwann cells were more abundant in the proximal, middle, and distal segments of the vascularized nerve graft group at all time points. Based on the above findings, the immediate restoration of circulation in the vascularized nerve graft can be accountable for the increased number of surviving Schwann cells, the rapid clearing of axons, and myelin-sheath changes that occur during Wallerian degeneration, thus enabling "morphologically" optimal regeneration.     

Role of a muscle target organ on the regeneration of motor nerve fibres in long nerve grafts: A synopsis of experimental and clinical data

The importance of the muscle target organ as a promoting factor for nerve fibre regeneration in nerve grafts is still a subject of controversial discussion. In the last few years we published uniform results of experimental series in sheep and rabbits in which we investigated the biology of nerve fibre regeneration in long nerve autografts without connection to a target organ. Surprisingly, we found excellent regeneration of myelinated nerve fibres without the influence of a target organ through the whole length of the nerve graft, with an increase in the number of nerve fibres up to fourfold at the distal end. In the sheep series the additional contact with a muscle target organ for 6 months had a variable effect on the fibre population in the distal end of the nerve graft. The results of our planimetric analyses of nerve biopsies in patients with facial paralysis, who were treated by cross-face nerve grafting and free muscle transplantation, are extremely divergent from the results of our experimental series. Instead of an increase, we found a decrease in number of regenerating nerve fibres arriving at the distal end of the cross-face nerve graft down to 20%. Species-specific differences in the biology of nerve regeneration are discussed, together with their implications for the complex clinical situation of nerve grafting with or without the influence of a target organ. © 1996 Wiley-Liss, Inc.     

Meaningful power grip recovery after salvage reconstruction of a median nerve avulsion injury with a pedicled vascularized ulnar nerve

In cases of median nerve injury alongside an unsalvageable ulnar nerve, a vascularized ulnar nerve graft to reconstruct the median nerve is a viable option. While restoration of median nerve sensation is consistently reported, recovery of significant motor function is less frequently observed. The authors report a case involving a previously healthy man who sustained upper arm segmental median and ulnar nerve injuries and, after failure of sural nerve grafts, was treated with a pedicled vascularized ulnar nerve graft to restore median nerve function. Long-term follow-up showed near full fist, with 12 kg of grip strength, key pinch with 1.5 kg of strength and protective sensation in the median nerve distribution. The present case demonstrates that pedicled ulnar vascularized nerve grafts can provide significant improvements to median nerve sensory and motor function in a heavily scarred environment.     

The difference in E-cadherin expression between nonvascularized and vascularized nerve grafts: study in the rat sciatic nerve model

BACKGROUND: We investigated the expression of E-cadherin during nerve regeneration after nonvascularized and vascularized nerve grafts. MATERIALS AND METHODS: We used the rat sciatic nerve model. E-cadherin expression was detected by Western blot analysis and immunofluorescent staining with anti E-cadherin monoclonal antibody. The level of E-cadherin expression was calculated as the amount relative to that of E-cadherin expression of normal control nerve. Furthermore, repair of the neural tissue structure was examined by toluidine blue staining. RESULTS: In both cases, the level of E-cadherin expression decreased at first, and then gradually increased. The maximum level was 1.61 +/- 0.066-fold in the nonvascularized nerve graft and 2.254 +/- 0.071-fold in the vascularized nerve graft. From the 1st to the 16th postoperative weeks, the level of E-cadherin expression in the vascularized nerve graft was significantly higher than that in the nonvascularized nerve graft. In the immunofluorescent staining, E-cadherin expression was almost negative or decreased immediately after the operation, but the degree of expression was gradually increased in Schwann cells. The degree of E-cadherin expression in the vascularized nerve graft was greater than that in the nonvascularized nerve graft. In toluidine blue staining, the velocity of tissue repair was more rapid in the vascularized nerve graft than in the nonvascularized graft. CONCLUSION: These results demonstrate that the E-cadherin expression of grafted nerve was increased during the nerve regeneration, and the expression was mainly observed in Schwann cells. Because the level of E-cadherin expression was significantly higher in the vascularized nerve graft than in the nonvascularized nerve graft, the level of E-cadherin expression may affect the rapidity of nerve regeneration.     

Histomorphometric studies in patients with facial palsy treated by functional muscle transplantation: new aspects for the surgical concept

Whenever it was possible, muscle and nerve biopsies were performed in patients with irreversible, unilateral facial palsy treated by cross-face nerve grafting and free gracilis muscle transplantation with microneurovascular anastomoses. Planimetric analyses of cross-sections showed the following, to some extent, surprising, results: (1) Independent of the final functional result, approximately the same number of regenerated, thin nerve fibers (100-200) were found in the distal end of the cross-face nerve graft at the time of muscle transplantation. These are approximately 20% of the nerve fibers counted in the branches of the facial nerve at the healthy side used for reinnervation. (2) There is no correlation between the number or diameter of the nerve fibers in the distal end of the cross-face nerve graft and the functional recovery of the transplanted muscle, but there is good correlation between the morphology of the fibers of the muscle graft and the functional result. (3) Different portions of slow-contracting and fast-contracting muscle fibers in the reinnervated muscle grafts showed the strong influence of the quality of the nerve used for the crossover innervation. If a facial nerve branch innervating the slow buccinator muscle was used, the originally fast gracilis muscle was transformed to a slow muscle by this kind of reinnervation. These important findings are the basis of a new view of surgery in the treatment of irreversible facial palsy by functional free-muscle transplantation.     

Comparison of the pattern of early revascularization of conventional versus vascularized nerve grafts in the canine

Blood flow to both conventional and vascularized canine saphenous nerve grafts was quantitated at two, 24, and 72 hours postoperatively, using radionuclide-labeled microspheres. For all time periods vascularized nerve grafts demonstrated adequate blood flow equal to or exceeding normal nerve controls. In contrast, conventional nerve grafts exhibited no significant fascicular revascularization in the first 24 hours, and only one of three dogs demonstrated adequate blood flow by three days postoperative.     

Anatomic basis of vascularized ulnar nerve graft by the pedicle of the superior collateral ulnar artery

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C_7神经移位重建截瘫双下肢功能的实验研究及初步临床应用

目的观察大鼠桡神经移位修复股神经,重建股四头肌功能的效果,并应用C7神经根移位,通过长段神经桥接修复股神经,重建截瘫患者双下肢的部分功能。方法SD大鼠16只,随机分为两组。A组:将左侧桡神经切断,近端牵至锁骨下切口内,经吻合血管的坐骨神经进行桥接,一期修复同侧股神经;B组:行桡神经与桥接神经吻合,术后3个月再切断同侧股神经并与桥接神经吻合。观察指标为电生理、股四头肌湿重恢复率、肌纤维截面积恢复率、有髓神经纤维通过率及截面积恢复率。临床上应用C7神经根为动力神经源,将胫神经自小腿远端切断并向近端游离至臀部,应用带血管蒂的胫神经反转至颈部与C7神经吻合,待胫神经自颈部再生到臀部后,再将胫神经与股神经吻合来治疗2例截瘫患者。结果B组股四头肌湿重、肌纤维截面积恢复率均优于A组;两组有髓神经纤维通过率、截面积恢复率及肌肉复合动作电位波幅比较差异无显著性意义。1例随访41个月,左侧股四头肌肌力恢复至4-级,右侧3级;另1例随访24个月,双侧股四头肌肌力恢复至2-级。结论周围神经具有强大的再生能力。C7移位分期修复股神经可重建截瘫患者下肢的部分感觉、运动功能。     

小隐静脉-腓肠神经逆行筋膜瓣的临床应用

目的 探讨应用小隐静脉-腓肠神经筋膜瓣联合全厚皮片移植修复小腿远段及足踝部软组织缺损的临床疗效. 方法 在小腿后侧设计小隐静脉-腓肠神经的筋膜瓣联合全厚皮片移植治疗小腿远段及足踝部单纯软组织缺损12例,软组织缺损伴胫骨骨髓炎3例、跟骨骨髓炎2例,皮肤缺损范围3cm×5 cm～9 cm×13 cm,切取筋膜瓣最大13 cm×18 ca.供筋膜瓣区保留皮肤及髂腹股沟取皮区皮肤均直接缝合. 结果 术后17例筋膜瓣联合全厚植皮均完全成活,成功治愈软组织缺损及骨髓炎,筋膜瓣供区、受区以及髂腹股沟取皮区均一期愈合,所有病例获得随访,随访时间为6～12个月,平均9个月,外形平整美观,供区保留皮肤感觉正常. 结论 带小隐静脉-腓肠神经筋膜瓣联合全厚皮片移植既能充分治愈小腿远段及足踝区软组织缺损以及骨髓炎,同时也能最大程度保护患肢功能及整体外观.