Peripheral nerve injury and repair

Peripheral nerve injuries are common, and there is no easily available formula for successful treatment. Incomplete injuries are most frequent. Seddon classified nerve injuries into three categories: neurapraxia, axonotmesis, and neurotmesis. After complete axonal transection, the neuron undergoes a number of degenerative processes, followed by attempts at regeneration. A distal growth cone seeks out connections with the degenerated distal fiber. The current surgical standard is epineurial repair with nylon suture. To span gaps that primary repair cannot bridge without excessive tension, nerve-cable interfascicular auto-grafts are employed. Unfortunately, results of nerve repair to date have been no better than fair, with only 50% of patients regaining useful function. There is much ongoing research regarding pharmacologic agents, immune system modulators, enhancing factors, and entubulation chambers. Clinically applicable developments from these investigations will continue to improve the results of treatment of nerve injuries.     

Peripheral nerve repair with nerve growth factor and fibrin matrix

Summary A fibrin sealant matrix (FS) with or without a nerve growth factor (NGF) has been used to improve the recovery of severed peripheral nerves, and these have been compared with the results of using only the standard epineural suture (SUT). Regeneration in the early phase (up to 6 days) was measured by the pinch test. The functional recovery process (up to 12 weeks) was evaluated by serial gait track analysis. Longitudinal sections of the nerve specimens were submitted to immunohistochemical staining with monoclonal antibody against neurofilament. In addition, the release of the NGF from the NGF-FS matrix in vitro was investigated by ELISA. The regeneration of the leading sensory fibers was significantly faster in both FS groups (with and without NGF) than in the SUT group at 3 and 4 days postoperatively. The behavioural data expressed by the sciatic function index (SFI) and the toe spreading index (TSI) indicated significant improvement in NGF-FS group at the 9th week postoperatively (p<0.05). Histologically, good and excellent outgrowth of neurites was encountered in both the NGF-FS and FS groups, while most of the results from SUT group were poor to satisfactory. In vitro, a peak of NGF release was seen within 18 h; afterwards, release remained slow for two weeks. It has been concluded that local application of a combination of FS and NGF may be useful for neuritic regeneration and subsequent functional recovery; the fibrin matrix itself may be beneficial for neuritic sprouting in the early phase.     

组织工程神经在修复周围神经缺损中的应用

周围神经缺损的修复与重建是当前神经领域的一大难题。目前，国内外学者已着力研究雪旺细胞和生物材料复合构建组织工程化人工神经，并将其与日益完善的显微外科技术结合起来，提高周围神经损伤的修复水平。本文结合国内外研究成果，对周围神经损伤修复的研究进行回顾，着重从组织工程方面阐述周围神经修复方法的现状与前景。     

Peripheral nerve block techniques for ambulatory surgery

Peripheral nerve blocks (PNBs) have an increasingly important role in ambulatory anesthesia and have many characteristics of the ideal outpatient anesthetic: surgical anesthesia, prolonged postoperative analgesia, and facilitated discharge. Critically evaluating the potential benefits and supporting evidence is essential to appropriate technique selection. When PNBs are used for upper extremity procedures, there is consistent opioid sparing and fewer treatment-related side effects when compared with general anesthesia. This has been demonstrated in the immediate perioperative period but has not been extensively investigated after discharge. Lower extremity PNBs are particularly useful for procedures resulting in greater tissue trauma when the benefits of dense analgesia appear to be magnified, as evidenced by less hospital readmission. The majority of current studies do not support the concept that a patient will have difficulty coping with pain when their block resolves at home. Initial investigations of outpatient continuous peripheral nerve blocks demonstrate analgesic potential beyond that obtained with single-injection blocks and offer promise for extending the duration of postoperative analgesia. The encouraging results of these studies will have to be balanced with the resources needed to safely manage catheters at home. Despite supportive data for ambulatory PNBs, most studies have been either case series or relatively small prospective trials, with a narrow focus on analgesia, opioids, and immediate side effects. Ultimately, having larger prospective data with a broader focus on outcome benefits would be more persuasive for anesthesiologists to perform procedures that are still viewed by many as technically challenging.     

Quantification of nerve tension after nerve repair: correlations with nerve defects and nerve regeneration

This study tested the validity of a quantitative in vitro nerve-tension-measuring technique, by correlating the tension measurements with functional and morphologic assessments of nerve regeneration. Initially, harvested nerves were used in vitro to determine a K value for lateral displacement in this tissue. Next, this value was used to calculate the tension of nerve repair, following 0-, 3-, 6-, and 9-mm resections of nerves in groups of rats. After quantifying the nerve tensions following excision and repair, the authors determined a sciatic function index to evaluate functional recovery and axon diameter in the animals. Functional recovery was significantly impaired in animals with elevated measurable tension (9.04 +/- 0.74 g in a 6-mm defect, 27.76 +/- 8.86 g in a 9-mm defect), compared to animals with no or 3-mm excision and measured tension of 3.3 +/- 1.09 g or less. Increased tension was also associated with a significant decrease in axon diameter. This study succeeded, therefore, in quantitatively relating the elements of measured nerve tension, nerve gaps, functional nerve recovery, and morphologic regeneration. Quantification of nerve tension by lateral displacement in vivo offers a possible solution to clinical management of nerve gaps, when the choice between primary repair and nerve grafting is not a clear one.     

Peripheral nerve repair and grafting techniques: a review

In this review, various conventional nerve repair techniques including direct epineurial repair, grouped fascicular repair, fascicular repair, and nerve grafting are described. The indications for use, as well as the relative advantage and disadvantage, of each technique are discussed. The experimental and clinical evidence from a review of the pertinent literature does not demonstrate a significant difference in outcome of one method over the others. Surgical decisions should be made by a thorough evaluation of all aspects of the nerve injury and surgical methods. All nerve injuries cannot be repaired using only one type of nerve repair method. The surgeon should be familiar with all the techniques described and be prepared to use them under appropriate circumstances.     

Peripheral nerve injuries and repair in the upper extremity

Peripheral nerve injuries are commonly seen as a result of domestic, industrial, or military trauma. Sharp objects usually cause these nerve injuries. When assessing these injuries, it is important to evaluate each nerves' motor and sensory function. One must be cognizant of associated injuries such as fractures, vascular damage, and musculotendinous lacerations. The time since the injury, level of injury, and age of the patient are important prognosticators impacting the return of function. Intraoperatively, one must assess the vascularity of the soft tissue bed and the nerve itself, the nerve gap, conduction, and the topography of the fascicles to insure proper orientation. Application of the principles of nerve repair (magnification, minimal tension, meticulous soft tissue handling, experienced surgeon and staff) can enhance the chances for a successful result. Additionally, to maximize functional recovery following peripheral nerve repair, a carefully planned program of postoperative occupational therapy and rehabilitation must be instituted.     

Peripheral and spinal motor reorganization after nerve injury and repair

Functional recovery after peripheral nerve injury depends on the amount as well as on the accuracy of reinnervation by regenerative axons. In this study, the rat sciatic nerve was subjected to crush injury or complete transection repaired by either (1) straight nerve suture, (2) crossed nerve suture of tibial and peroneal fascicles, or (3) silicone tubulization leaving a gap of 4 mm. The compound muscle action potentials (CMAP) of gastrocnemius, tibialis anterior and plantar muscles were recorded 90 days post operation to assess functional reinnervation and Fast Blue, Fluoro Gold and DiI were applied to the nerve branches projecting into these muscles to quantify morphological reinnervation. The CMAP amplitude achieved in gastrocnemius, tibialis anterior and plantar muscles was higher after nerve crush (86%, 82%, 65% of control) than after any surgical nerve repair (straight suture: 49%, 53%, 32%; crossed suture: 56%, 50%, 31%; silicone tube: 42%, 44%, 25%). The total number of labeled motoneurons, however, did not significantly differ between groups (control: 1238 +/- 82, crush: 1048 +/- 49, straight suture: 1175 +/- 106, crossed suture: 1085 +/- 84, silicone tube: 1250 +/- 182). The volume occupied by labeled motoneurons within the spinal cord was larger after surgical nerve repair than in crush or normal control animals, and fewer neurons showed abnormal multiple projections after crush (2.5%) or straight suture (2.2%) than following crossed suture (5%) or silicone tube (6%). In conclusion, nerve repair with a silicone tube leaving a short gap does not increase accuracy of reinnervation.     

睫状神经营养因子涂层的聚羟基乙酸聚乳酸神经导管修复犬胫神经缺损

目的 探讨应用脉冲等离子体方法涂层睫状神经营养因子（CNTF）的聚羟基乙酸聚乳酸（PGLA）神经导管修复犬胫冲经缺损的疗效。方法 18只杂交犬．每只犬左后肢制成胫神经2．5cm缺损模型，随机分别应用三种方法修复。A组：应用脉冲等离子体方法涂层CNTF的PGLA神经导管；B组：单纯PGLA神经咩管；C组：自体神经。应用苏木精-伊红和Masson染色、S-100免疫组化染色、神经电生理及神经轴突计数方法评价神经再生效果。同时动态记录犬行走步态变化，实验观察期3个月。结果 神经导管血管化良好且大部分降解吸收，再生神经均已通过所有神经导管。A组与C组的神经传导速度和神经轴突计数差异无统计学意义（P〉0．05），而A组和C组的数据均优于B组（P〈0．05）。A组和C组的犬基本恢复正常行走步态，而B组犬仍有跛行。结论 脉冲等离子体方法涂层CNTF的PGLA神经导管能有效修复犬2．5cm胫神经缺损，取得与自体神经相近的效果。     

脉冲等离子体涂层神经导管修复周围神经缺损实验研究

目的:探讨经脉冲等离子体涂层并固定睫状神经营养因子(CNTF)的聚羟基乙酸和聚乳酸共聚物(PGLA)神经导管修复周围神经缺损的效果.方法:应用脉冲等离子方法对PGLA膜片或神经导管表面进行处理,然后固定CNTF.该膜片表面种植人胚胎视神经细胞,经处理的神经导管修复SD大鼠坐骨神经1.5 cm缺损.观察人胚胎视神经细胞在经处理的膜片上生长情况,并用电生理和轴突计数法评价经处理的神经导管内神经再生质量.设立未固定CNTF的PGLA膜片组和未经过脉冲等离子体涂层的神经导管组作为对照组比较.结果:在经处理的PGLA膜片上,人胚胎视神经细胞生长较对照组密集,且发现有轴突延伸相接现象.经处理的PGLA修复大鼠坐骨神经缺损,在1个月和3个月时,均发现神经导管内神经传导速度和再生神经轴突均明显大于对照组(P＜0.05).结论:经脉冲等离子体涂层并固定睫状神经营养因子(CNTF)的PGLA神经导管可能通过CNTF的接触诱导和持续缓释作用,促进周围神经再生.     

组织工程化人工神经修复周围神经缺损的实验研究

目的　研究雪旺细胞和生物降解支架材料复合后构建成的组织工程化人工神经修复神经缺损的效果。方法　将雪旺细胞制成 1× 1 0 8/ml的ECM (extracellularmatrix,ECM)凝胶 ,与PLA无纺纤维布复合培养 7d ,置入PLA中空纤维管中 ,构建成组织工程化人工神经。建立大鼠坐骨神经缺损 1 0mm的动物模型 ,A组为人工神经组 ;B组为雪旺细胞复合ECM凝胶组 ;C组为单纯ECM凝胶组 ;D组为自体神经移植组。术后 8周、1 2周 ,行神经电生理和组织学检测评价疗效。结果　术后 1 2周A组的再生神经纤维已越过远端缝合口 ,有髓神经纤维数和神经纤维密度稍差于D组 ,但再生神经组织的面积显著高于后者 ;A、D组的髓鞘厚度和dLAT、NCV、AMP、AREA均无显著差别 ,但明显高于B、C组。结论　雪旺细胞、ECM凝胶和PLA多孔材料与PLA中空纤维管组合后构建成的组织工程化人工神经 ,修复周围神经缺损的效果接近于自体神经移植     

Peripheral nerve block during ambulatory surgery of varicose veins]

This retrospective study of the 46 operations, carried out over a one year period for lower limb varicose veins using peripheral nerve blocks, included 45 patients (35 women and 10 men, mean age 49.3 years), all ASA 1 or 2, except for 4 elderly patients with a varicose ulcer (ASA 2 or 3). In 40 procedures, a sciatic nerve block combined with a "3 in 1" lumbar plexus block at the level of the groin (as described by Winnie) were used. In the remaining six, either a sciatic nerve block (short saphenous vein crossectomy; n = 3), or a "3 in 1" lumbar plexus block alone (short stripping of the long saphenous vein; n = 3) were required. A peripheral nerve stimulator to locate accurately each nerve was used. For each nerve block, the anaesthetic mixture consisted of 20 ml lidocaine 1.5% with 1:200,000 adrenaline, and 10 ml of bupivacaine 0.375% with 1:200,000 adrenaline. Surgery was only performed on one limb at a time, as the required dose of local anaesthetic was too high to safely carry out bilateral nerve blocks. In 71.7% of patients surgery was made on an day-case basis. Of those patients who had to remain in hospital overnight or longer, the peripheral nerve block was never responsible for this. During the same period, nine similar procedures were carried out under general anaesthesia, and two under epidural anaesthesia. They included seven bilateral varicose veins, three patient refusals for peripheral nerve blocks, and one allergy to lidocaine. Already used for some procedures in orthopaedic and casualty surgery, peripheral nerve blocks seem to be well suited for surgery of unilateral varicose veins.     

Plastic surgery repair of abdominal wall and pelvic floor defects

Urologists often encounter large perineal and abdominal wall defects, the treatment of which may require close collaboration with the plastic surgeon. These complex defects can be successfully treated using a variety of techniques. Ventral hernias or freshly created abdominal wall defects can be treated with the basic principles of tension-free closure using abdominal wall components separation, synthetic mesh reconstruction, and, more recently, biosynthetic acellular dermis reconstruction. Pelvic floor defects often require flap reconstruction using gracilis flaps, vertical rectus abdominis myocutaneous flaps, or local fasciocutaneous flap. In this article, we seek to familiarize the urologists with the most common techniques used by plastic and reconstructive surgeons in the treatment of these complicated pelvic floor and abdominal wall defects.     

Peripheral nerve repair using muscle autografts. Recovery of transmission in primates

Skeletal muscle grafts, when thawed after freezing, can be used to repair peripheral nerves. This method was used after transection of the median nerve in the upper arm in marmosets. Examination at 28 days showed total denervation of flexor carpi radialis; at 150 days electrophysiological evidence of recovery of nerve conduction across the graft and of muscle activation was seen. Sections at this time showed nerve fibres and new functional neuromuscular junctions in the muscle. It is concluded that effective reinnervation of target muscles is possible after peripheral nerve repair using skeletal muscle autografts.