Repair and reconstruction of peripheral nerve injuries

Axonal regeneration after transection is a complex biological process. It is not merely a process of tissue repair, but rather of cellular repair of a large number of nerve cells. Regeneration involves restoration of the original morphology of each single cell, rather than proliferation. Techniques in microneurosurgical reconstruction of peripheral nerve injuries have improved over the last two decades, with subsequent improvement in functional results. Nerve autografts are now routinely used to guide the regrowth of the proximal nerves to distal nerve segments. However, the limited source of expendable cutaneous nerves restricts the use of nerve grafting techniques and is associated with significant morbidity. With extensive injuries there is an insufficient quantity of nerve autograft material to facilitate optimal repair. In future, the use of artificial conduits or nerve allografts could provide a limitless source of material to reconstruct otherwise irreparable traumatic nerve injuries. Establishment of appropriate strategies to suppress host-immune reaction or donor antigenicity would facilitate clinical allogeneic nerve transplantation. Guest lecture presented at the 69th Annual Meeting of the Japanese Orthopaedic Association in Tokyo on April 13, 1996.     

Indication,technique and results of facial nerve reconstruction

Summary 160 patients with various intraor extracranial pathologies were treated by microsurgical facial nerve reconstruction at Nordstadt Neurosurgical Clinic between 1978 and 1993. Facial nerve reconstruction was accomplished along the anatomical course of the facial nerve from its origin at the brainstem, within the mastoid, at the stylomastoid foramen and within the face. Mostly, reconstruction was indicated because of nerve discontinuity (n=61), whereas facial nerve reanimation with a donor nerve such as the contralateral facial nerve or the ipsilateral hypoglossal nerve was indicated in 99 cases of loss of a proximal nerve stump. Depending on the site of the lesion reinnervation started at 5 to 15 months postoperatively lasting for 2 to 3 years with overall satisfactory results. 69% of all the patients regained good symmetry on rest, complete eye closure equivalent to House-Brackmann-Score III: Patients with complete failures either suffered of non-related diseases such as cancer leading to death before the estimated time of recovery or were exposed to radiation or received facial nerve reconstruction after long-standing facial deficit and marked muscular atrophy. The indication of the adequate method depends on the clinical course with or without preexisting facial paresis, on considering the intraoperative state of the facial nerve, the identification and microsurgical preparation of adequate nerve stumps, as well as on the adaptation techniques and the postoperative guidance of the patient. We conclude that facial nerve reconstruction by transplantation at either site of the nerve course or by reanimation with a donor nerve are effective and reliable procedures of treatment leading to satisfactory functional and cosmetic results.     

Current concepts in diagnosis and management of common upper limb nerve injuries in children

Peripheral nerve injuries (PNI) of the upper limb are a common event in the paediatric population, following both fractures and soft tissues injuries. Open injuries should in theory be easier to identify and the repair of injured structures performed as soon as possible in order to obtain a satisfying outcome. Conversely, due to the reduced compliance of younger children during clinical assessment, the diagnosis of a closed nerve injury may sometimes be delayed. As the compliance of patients is influenced by pain, anxiety and stress, the execution of the clinical manoeuvres intended to identify a loss of motor function or sensibility, can be impaired. Although the majority of PNI are neuroapraxias resulting in spontaneous recovery, there are open questions regarding certain aspects of closed PNI, e.g. when to ask for electrophysiological exams, when and how long to wait for a spontaneous recovery and when a surgical approach becomes mandatory. The aim of the article is therefore to analyse the main aspects of the different closed PNI of the upper limb in order to provide recommendations for timely and correct management, and to determine differences in the PNI treatment between children and adults.     

坐骨神经干肿瘤的诊断和治疗

目的 提高对坐骨神经干肿瘤的认识,避免误诊误治。方法 总结７例坐骨神经干肿瘤的诊断和治疗经验。结果 ７例中韧带状瘤３例,横纹肌肉瘤１例,恶性纤维组织细胞瘤３例。随访５个月－８年,韧带状瘤３例复发,再次手术切除,横纹肌肉瘤１例复发后拒绝治疗,余３例未复发。结论 坐骨神经干肿瘤的诊断必须进行细致的坐骨神经干的扪诊检查;治疗以根治手术为主,辅以化疗或放疗。     

Long-term results of transplantations to repair median, ulnar, and radial nerve lesions by a microsurgical interfascicular autogenous cable graft technique

A comprehensive analysis of 187 patients (78 median, 86 ulnar, and 23 radial nerve lesions) treated by an interfascicular autogenous nerve grafting technique is presented. After a follow-up of at least 18 months good motor recovery was achieved in 72% of median nerve lesions, 77% of ulnar nerve lesions, and 57% of radial nerve lesions. Good functional sensory recovery was found in 36% of median, 45% of ulnar, and 48% of radial nerve lesions. It appears by multivariate analysis that the results obtained generally were better in younger patients, in patients with a shorter preoperative delay, and in cases with a shorter transplant.     

Occurrence of vestibular and facial nerve injury following cerebellopontine angle operations

Summary To elucidate how surgery in the cerebellopontine (CP) angle may cause vestibular and facial nerve injury, the 7th and 8th cranial nerves of dogs were manipulated as in human surgery along with monitoring of auditory evoked brain stem responses. Postoperatively, histological examinations were performed to investigate the effect of the surgical manipulations.We found that the occurrence of vestibular, facial and cochlear nerve injury was dependent on the direction of theexcessive movement of the nerves in the cerebellopontine (CP) angle. Caudal-to-rostral shift of the nerve trunk most effectively avulsed the vestibular nerve. Haemorrhages were revealed between the vestibular ganglion and the fundus of the internal auditory canal. This caudal-to-rostral retraction could also damage the facial nerve in its intrapetrous labyrinthine portion. This was likely to be one of the pathophysiological mechanisms responsible for postoperative facial nerve palsy occasionally observed in human cases.Rostral-to-caudal retraction of the cerebellum damaged the cochlear nerve selectively. Although caudal-to-rostral retraction, instead of lateral-to-medial one, has been recommended to protect the cochlear nerve, this retraction was shown to be dangerous to the vestibular nerve if excessive.The clinical significance of the fragility of the vestibular nerve was discussed and the importance of preserving the vestibular nerve function is stressed.     

Tendon transfers for radial, median, and ulnar nerve injuries: current surgical techniques

Tendon transfers are performed predominantly to restore hand function or balance due to injuries of the radial, median, and ulnar nerves. Current surgical techniques for the most common tendon transfers for reconstruction of radial, median, and ulnar nerve palsies are demonstrated. These techniques can also be applied to restore flexion and extension of the fingers and thumb after injuries to the extrinsic flexor and extensor muscles and tendons of the forearm or intrinsic muscles of the hand.     

腰骶部脊神经后根选择性切断术治疗痉挛性脑瘫的应用解剖及临床疗效观察

目的通过对腰骶部脊神经根形态及周围结构的应用解剖详细观测,以寻求一种对脑瘫双下肢痉挛的治疗既能使肢体运动力功能改善快,且手术创伤小,发生并发症亦少的手术方式。方法在手术显微镜下操作及解剖观测儿童标本４０具,成人标本６０具的腰骶部脊神经根及周围结构。结果儿童自然根丝为４～６束、成人为８～１２束,集成２干形成后根到达硬脊膜初级孔。在儿童标本中硬脊膜内侧段长度为４～１５ｃｍ,在成人标本中其长度为６～２０ｃｍ。棘突根部下缘与椎板下缘交点是两侧脊神经后根穿出椎间孔处连线的对应点。以棘突根部下缘作为寻找同序数脊神经后根的标志,改良了选择性脊神经后根切断术（ＳＰＲ）,临床应用２００例,疗效明显优于非改良的手术治疗。结论棘突根部下缘可作为寻找同序数脊神经后根的标志,改良ＳＰＲ术式具有切口小、脊柱稳固、功能改善快等优点。     

Ultrastructural study of rabbit sciatic nerve regeneration following experimental excisional transection and autograft reconstruction

Summary This experimental study presents the ultrastructure of regenerating sciatic nerve of the rabbit, after transection and immediate end to end anastomosis, using perineural fascicular nerve autograft, in a sterile environment.Twenty-four hours, 1, 2, and 6 weeks after the anastomosis, the treated sciatic nerves were exposed and three segments were excised and studied. The first at the region of the graft and the others from the proximal and distal stump of the nerve, in the vicinity of the graft suture. The sections taken from the proximal part showed that the nerve structure was identical with the control. Degeneration and regeneration of nerve fibres were observed on the sections taken from the region of the grafts and from the distal parts. Macrophagic activity appeared mainly one week after the operation. Fibroblastic invasion started 24 hours after operation. A moderate amount of collagen fibres was gradually formed. The fibres were disposed in parallel with the neuraxon. Schwann cells were slightly affected initially but consequently they fully recovered and showed signs of extra-activity of the cytoplasm organelles,e.g., enlargement of the granular endoplasmic reticulum cisternae.The present study showed that the bridging of experimental gaps of rabbit's sciatic nerve, by means of autograft and by use of perineural suturing, was sucessful. The regenerating nerve fibres were growing through the graft towards the distal part of the nerve. In this process Schwann cells and fibroblastic activity play a key role, which is most favourably influenced by using the technique described in this paper.     

Increases in callus formation and mechanical strength of healing fractures in old rats treated with parathyroid hormone

We studied the effects of intermittent administration of parathyroid hormone (PTH(1-34)) on callus formation and mechanical strength of tibial fractures in 27-month-old rats after 3 and 8 weeks of healing. 200 &#119 g PTH(1-34)/kg was administered daily during both periods of healing, and control animals with fractures were given vehicle. At 3 weeks, PTH treatment increased maximum load and external callus volume by 160% and 208%; at 8 weeks, by 270% and 135%. It also enhanced callus bone mineral content (BMC) by 190% and 388% (3 and 8 weeks). From week 3 to week 8, callus BMC increased by 60% in the vehicle-injected animals, and by 169% in the PTH-treated animals. In the contralateral intact tibia, PTH treatment increased BMC by 18% and 21% (3 and 8 weeks). No differences in body weight were found between the vehicle-injected and the PTH-treated animals during the experiment. In conclusion, PTH treatment enhances fracture strength, callus volume and callus BMC after 3 and 8 weeks of healing.     

髋臼骨折脱位合并坐骨神经损伤的治疗和预后

目的了解髋臼骨折脱位坐骨神经损伤概率、损伤程度,以及手术治疗与非手术治疗的疗效。方法自1999年7月～2007年8月收治208例髋臼骨折脱位合并坐骨神经损伤31例,手术治疗13例,非手术治疗18例。结果手术治疗的13例中8例有胫神经损伤表现,术前胫神经平均分为3.54分(按照LSUHSC评分),3例术后有恢复,4例完全恢复正常,1例未恢复,术后胫神经评分平均为4.77分。13例术前腓总神经平均分为2.23分,术后6例有恢复,2例恢复正常,5例没有恢复,术后腓总神经平均分为2.69分。非手术治疗的18例中14例有胫神经损伤,术前胫神经平均分为3.67分,13例有恢复,12例完全恢复正常,术后胫神经平均分为4.89分。非手术治疗病人都有腓总神经损伤,治疗前腓总神经平均分2.39分,治疗后13例有恢复,3例恢复正常,5例没有恢复,术后腓总神经平均分为3.39分。统计手术治疗与非手术治疗没有明显差异(P=0.206)。胫神经恢复好于腓总神经(P0.01)。结论髋臼骨折引起的坐骨神经损伤,其中腓总神经分支损伤更多见、更严重,无论手术治疗还是非手术治疗恢复都比胫神经差;坐骨神经损伤手术治疗效果并不优于非手术治疗。     

人体膈神经与副膈神经的组织化学研究

研究人体膈神经与副膈神经的运动纤维数量及有髓纤维截面积。方法：运用Ｋａｍｏｖｓｋｙ－Ｒｏｏｔｓ［１］乙酰胆碱酯酶组织化学方法，研究１２例成人膈神经及并存的５例副膈神经。对轴索内酶活性反应呈阳性的纤维，进行计数及纤维截面积图象分析。结果：膈神经与副膈神经绝大部分有髓纤维酶反应呈阳性，所含阳性有膈纤维分别为２６８６根、６３４根。膈神经与副膈神经并存时有髓纤维总数达３２１８根。有髓纤维截面积分别为１０３．８μｍ２、９４．７μｍ２。结论：膈神经含２６８６根运动纤维，有髓纤维截面积为１０３．８μｍ２，是良好的移位动力神经；副膈神经与其并存，有重要的临床意义。