缓慢牵伸肢体延长时周围神经生物学适应性机理的实验研究

目的研究缓慢牵伸肢体延长对周围神经的影响及其修复机理。方法以80只体重为2．0～2．5kg的日本大耳白兔为实验对象,分别于其胫骨延长10％、20％、30％、40％及延长40％停止后2、4、8周,观察延长各时相胫后神经组织学、电生理学的改变及相应脊髓、神经节生长相关蛋白-43mRN0A的表达变化。结果肢体延长主要造成以周围神经脱髓鞘病变为主的病理损害,随着延长幅度的增加,损害亦渐明显,但同时又存在神经的再生修复。结论缓慢牵伸在造成周围神经亚临床损害的同时,亦存在着神经的再生修复,以每日1mm的速度延长肢体,神经损害可在短期内逐渐修复。     

Effect of progesterone on recovery from nerve injury during leg lengthening in rats

We investigated the effect of progesterone on the nerve during lengthening of the limb in rats. The sciatic nerves of rats were elongated by leg lengthening for ten days at 3 mm per day. On alternate days between the day after the operation and nerve dissection, the progesterone-treated group received subcutaneous injections of 1 mg progesterone in sesame oil and the control group received oil only. On the fifth, tenth and 17th day, the sciatic nerves were excised at the midpoint of the femur and the mRNA expression level of myelin protein P0 was analysed by quantitative real time polymerase chain reaction. On day 52 nodal length was examined by electron microscopy, followed by an examination of the compound muscle action potential (C-MAP) amplitude and the motor conduction velocity (MCV) of the tibial nerve on days 17 and 52. The P0 (a major myelin glycoprotein) mRNA expression level in the progesterone-treated group increased by 46.6% and 38.7% on days five and ten, respectively. On day 52, the nodal length in the progesterone-treated group was smaller than that in the control group, and the MCV of the progesterone-treated group had been restored to normal. Progesterone might accelerate the restoration of demyelination caused by nerve elongation by activating myelin synthesis.     

Tibial nerve function during tibial lengthening:Measurement of nerve conduction and blood flow in rabbits

We evaluated in 20 Japanese white rabbits the effects of tibial lengthening on tibial nerve conduction and intraneural blood flow at the end of lengthening. Both tibiae were distracted 1 mm per day. The distraction frequency was in 2 steps (0.5 mm/12 h) on the right side and in 120 steps (0.0083 mm/12 min) on the left. The rabbits were separated into 4 subgroups based on the percentage of lengthening: 0 (control), 10, 20, and 30 percent. In the 2-step group, nerve conduction was delayed at 20 and 30 percent lengthening, compared to the control group, while in the 120-step group, it was delayed only at 30 percent lengthening. Intraneural blood flow in the 2-step group was decreased at 10, 20, and 30 percent lengthenings, while in the 120-step group it was reduced at 30 percent lengthening. Our findings indicate that an increase in the frequency of distraction reduces the impairment of nerve function during bone lengthening.     

Effects of gradual bone lengthening on the rabbit tibial nerve

Little is known about the effect of gradual bone lengthening on peripheral nerves. In the present study, an external fixation device was applied to the rabbit tibia, which was then divided. After seven days, the tibia was subjected to 0.7 mm/day callus distraction for periods of up to one month. The tibial nerve was fixed in glutaraldehyde and plastic sections were cut in longitudinal and transverse planes for light and electron microscopy. Light microscopy showed a 64% increase in the gap length at the node of Ranvier in myelinated axons from the experimental side compared with the control side. The cross-sectional area of the non-myelinated axons was not altered significantly. We conclude that gradual stretching of the nerve elongates the nerve fibres at least at the region of the nodes, perhaps a point of least resistance. Diameters of fibres seem to be held more constant during the lengthening procedure.     

Effects of gradual bone lengthening on the rabbit tibial nerve.

Little is known about the effect of gradual bone lengthening on peripheral nerves. In the present study, an external fixation device was applied to the rabbit tibia, which was then divided. After seven days, the tibia was subjected to 0.7 mm/day callus distraction for periods of up to one month. The tibial nerve was fixed in glutaraldehyde and plastic sections were cut in longitudinal and transverse planes for light and electron microscopy. Light microscopy showed a 64% increase in the gap length at the node of Ranvier in myelinated axons from the experimental side compared with the control side. The cross-sectional area of the non-myelinated axons was not altered significantly. We conclude that gradual stretching of the nerve elongates the nerve fibres at least at the region of the nodes, perhaps a point of least resistance. Diameters of fibres seem to be held more constant during the lengthening procedure.     

大鼠坐骨神经急性延长的实验研究

目的 探讨急性扩张延长周围神经的合理注水量与延长值。方法 使用组织扩张器对3组（每组8只）大鼠坐骨神经行一次性扩张延长,注水量分别为3ml、5ml、7ml。分别于注水前、注水后即刻、注水后保持5min、去水囊后15min,进行肌电测定;并在光镜、透射电镜下进行组织学观察。结果 （1）延长值（起始长度均为1．5cm）：分别为8．33％、14．7％、20．4％。（2）肌电结果：3ml、5ml组的运动神经传导速度与复合肌肉电位（CMAP）的潜伏期,神经扩张前和扩张后相比无明显差别。7ml组则比术前明显减慢及延长。（3）轴突密度：3ml、5ml组扩张部与正常段神经相比无明显差异。7ml组轴突的密度则明显降低。（4）形态学：3ml、5ml组的神经结构基本正常,7ml组束膜间有血管扩张、间质水肿、出血及脱髓鞘变化。（5）超微结构：3ml、5ml组神经髓鞘为圆形,排列规则;7ml组神经髓鞘明显皱缩变形。结论 大鼠坐骨神经一次性扩张延长的合理注水量为5ml,延长值为14．6％。     

Entrapment neuropathies of the foot. Electromyographic techniques

Entrapment neuropathies frequently involve the foot. The diagnosis can be established by electrophysiological techniques for the exploration of muscles and nerves. Needle recording from the intrinsic foot muscles is a valuable asset in the detection of neurogenic syndromes. The motor and sensory nerve conduction velocities are determined using surface electrodes. The sensory nerve conduction study can be supplemented with somatosensory-evoked-potential studies. Based on these investigations, the location, severity and prognosis of the nerve lesion can be determined. In the presence of tunnel and compression syndromes involving the foot, studies of the tibial nerve (tarsal tunnel - Morton), peroneal nerve and sural nerve are of particular interest.     

New treatment for peripheral nerve defects: Reconstruction of a 2 cm,monkey median nerve gap by direct lengthening of both nerve stumps

We have developed a new treatment for peripheral nerve defects: nerve‐lengthening method, and confirmed the efficacy and safety of our method using cynomolgus monkeys. A 20‐mm defect in the median nerve of monkey's forearms was repaired through the simultaneous lengthening of both nerve stumps with original nerve‐lengthening device. To evaluate nerve regeneration after neurorrhaphy, electrophysiological, histological, and functional recovery were examined and compared to the standard autografting. Nerve conduction velocity, axon maturation, and the result of functional test were superior in the nerve‐lengthening method than in the autografting. And there were no adverse events associated with our method. We concluded that this method is practical for clinical application. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:153–161, 2012     

缓慢牵伸肢体延长周围神经损害自然修复过程的组织学研究

目的：观察缓慢牵伸肢体延长后周围神经损伤的自然修复过程及结局。方法：５２只日本大耳白兔胫骨延长到４０％后停止延长再分另继续观察２周、４周、８周,观察各时相延长区胫后神经组织学改变。结果：延长４０％时,可见广泛的节段性脱髓鞘,朗飞氏结区增宽,且主要发生于大的有髓神经纤维。电镜下可见髓鞘呈双环状,空泡状改变及环形小体形成压迫轴突。并可见新形成的髓鞘。停止延长后随着时间的延长,这种改变渐修复。至８周时基本恢复正常。结论：缓慢牵伸下肢延长过程中周围神经的损害是可逆的。并可在短期内修复。     

Monitoring of the sciatic nerve during hamstring lengthening by evoked EMG

Traction injury to the sciatic nerve can occur during hamstring lengthening. The aim of this study was to monitor the influence of hamstring lengthening on conduction in the sciatic nerve using evoked electromyography (EMG). Ten children with spastic cerebral palsy underwent bilateral distal hamstring lengthening. Before lengthening, the evoked potential was recorded with the patient prone. During lengthening, it was recorded with the knee flexed to 90 degrees, 60 degrees and 30 degrees, and at the end of lengthening with the hip and knee extended. In all patients, the amplitude of the evoked EMG gradually decreased with increasing lengthening. The mean decrease with the knee flexed to 60 degrees was 34% (10 to 77), and to 30 degrees, 86% (52 to 98) compared with the pre-lengthening amplitude. On hip extension at the end of the lengthening procedure, the EMG returned to the pre-lengthening level. Monitoring of the evoked EMG potential of the sciatic nerve during and after hamstring lengthening, may be helpful in preventing traction injury.     

Long-term results of lower limb lengthening by physeal distraction

Of the many methods of limb elongation, lengthening by physeal distraction is among the newest. The goal of this study was to estimate the long-term results of femoral and tibial lengthening by epiphyseal distraction. The authors examined 40 patients who underwent 24 femoral and 16 tibial lengthenings. The average follow-up period was 9.6 years. An average of 4.6 cm of femoral lengthening and 4.7 cm of tibial lengthening was achieved. The femoral healing index was 38.1 days/cm and the tibial healing index was 35.7 days/cm. After lengthening the epiphyseal cartilage started to function in all patients, and premature growth cartilage fusion was not observed during follow-up. Complications occurred in eight patients during femoral lengthening and in four during tibial lengthening. The authors suggest that physeal distraction is a good method for moderate and simple limb lengthening. Particular care should be applied to knee joint function, especially during femoral lengthening.     

Peripheral nerve lengthening by controlled isolated distraction: a new animal model.

We have developed a simple and effective animal model to study the distraction neurogenesis utilizing the sciatic nerve-lengthening technique in rats. The model allows macroscopic, physiological, and histological evaluation of the distraction site. Fourteen adult Harlan Sprague Dawley rats (300-350 g) were used in this study. A 10 mm segment of the right sciatic nerve of each animal in the nerve-lengthening group was resected. Gradual nerve lengthening was performed by advancing the proximal nerve stump at a rate of 1 mm/day. The proximal stump neuroma was then resected and a direct nerve anastomosis was performed. On the left side a standard autogenous nerve-grafting procedure was performed with a 10 mm segment of sciatic nerve used as an in situ nerve graft. Three months after the second surgery, the sciatic nerves were exposed and investigated by gross observation and EMG followed by histological processing and tissue analysis. Neomicrovascularization was observed surrounding the sciatic nerve anastomosis in all five specimens of the nerve-lengthening group as compared to the more white-colored scar tissue that was observed in the nerve-grafting group. The EMG results were similar for both groups. Histological studies of the lengthened nerves showed axon morphology equivalent to the grafted nerves. This study demonstrated a clear evidence of the successful nerve regeneration within a segmental nerve gap by nerve lengthening.     

The effect of tibial diaphyseal lengthening on the longitudinal growth of the tibia

Limb lengthening by tibial callotasis is usually performed in the metaphysis but may cause growth inhibition. Is diaphyseal lengthening more advantageous? Sixteen immature rabbits underwent 30% diaphyseal lengthening by tibial callotasis. The tibial length was measured on radiographs at the end of the distraction period and after an additional 5 weeks. The proximal and distal growth plates were assessed histomorphometrically. Osteotomy stimulated tibial elongation; however, combined with diaphyseal lengthening the stimulation was suppressed resulting in longitudinal growth that matched the control side. In longer lengthenings of limbs diaphyseal callotasis may be more advantageous than metaphyseal by not inhibiting longitudinal growth.     

Distribution of sodium channels during nerve elongation in rat peripheral nerve

A number of studies have investigated electrophysiological and morphological changes of peripheral nerves during gradual elongation. There has been, however, no report on the distribution of sodium channels at Ranviers nodes during peripheral nerve elongation. We investigated peripheral nerve injury after the gradual elongation of rat sciatic nerves. Indirect nerve elongation was induced by leg lengthening at a rate of 3mm/day by 15 or 30mm. At 7 days after the leg lengthening, the electrophysiological properties of sciatic nerves, the ultrastructures of the Ranviers nodes and axons, and the distribution of voltage-dependent sodium channels were examined. In the control nerves, most sodium channels were localized at Ranviers nodes in myelinated axons, providing the physiological basis of saltatory conduction. In the elongated nerves, both the amplitude and conduction velocity of compound nerve action potential decreased following leg lengthening. The elongated nerves also showed paranodal demyelination in Ranviers nodes longer than those in the control group. In addition, the distribution of sodium channels became diffuse or disappeared at Ranviers nodes of elongated nerves. The diffuse distribution and/or disappearance of sodium channels may underlie the electrophysiological changes in compound nerve action potential induced by nerve elongation.     

Nerve conduction and microanatomy in the rabbit sciatic nerve after gradual limb lengthening-distraction neurogenesis.

To clarify how the peripheral nerve adapts to elongation during gradual limb lengthening, electrophysiological and histomorphometric examinations were performed on the sciatic nerves in 18 rabbits. External fixators were used to lengthen the right femora by 30 mm (30%), at a daily rate of 0.5 mm (Group 1) or 2.0 mm (Group 2). Examinations were performed immediately after the limb lengthening procedure. Electrophysiologically, mild conduction slowing was observed in Group 1; a conduction block was evident in Group 2. Histologically, the mean diameter of myelinated fibers was unchanged in Group 1, but a significantly decreased diameter was observed in Group 2. Electron microscopy revealed that mild degenerative change of unmyelinated axons occurred sporadically in two cases in Group 2, but neither group showed evidence of thinning of myelin sheath of myelinated fibers. The mean internodal length (between nodes of Ranvier) of teased fibers was 1216+/-295 microm in the control contralateral side, 1484+/-347 microm in Group 1, and 1467+/-322 microm in Group 2. Thus the internodes were lengthened by 22.1% (Group 1) and 20.7% (Group 2) in comparison with those of the controls. Straightening of the geometry of paranodal myelin sheath was significantly correlated with the rate of distraction. These results indicate that myelinated nerve fibers adapt to gradual elongation by lengthening each Schwann cell body, not by proliferation of Schwann cells.     

Ilizarov外固定架在胫骨截骨延长治疗中的应用

目的：探讨Ilizarov外固定架在胫骨截骨延长治疗中的应用。方法：1990年1月～2002年12月对66例应用Ilizarov外固定架进行胫骨截骨延长的患者手术疗效进行分析。结果：延长长度最长9．3cm，最短5．7cm，平均7．3cm；延长时间24～128d，平均62d；拆架时间2．5～10个月，平均6．0个月；愈合指数27～56d／cm，平均34d／cm。无严重并发症发生，其中1例术后出现腓总神经损伤症状；4例出现不同程度的针道感染；6例出现膝关节屈曲受限；4例出现跟腱挛缩致足呈马蹄畸形。给予对症处理后好转。结论：应用Ilizarov外固定架技术对于胫骨截骨延长是一种有效的方法。     

去细胞异种神经复合神经生长因子修复神经缺损的实验研究

目的 应用含有神经生长因子(NGF)的去细胞异种神经基膜管作为神经移植替代物桥接大鼠坐骨神经缺损,观察其对神经再生的作用.方法 选用Wistar大鼠45只,随机分为3组,每组15只,于术制成右后肢坐骨神经长10 mm的神经缺损,取兔胫神经制成去细胞神经基膜管,电镜及HE染色观察神经基膜管超微结构,流式细胞仪检测去细胞前后神经主要组织相容性抗原Ⅱ(MHC Ⅱ)的变化情况.A组以含有NGF的去细胞异种神经基膜管桥接神经缺损,B组单纯采用去细胞异种神经基膜管桥接神经缺损,C组采用自体神经移植修复神经缺损.术后1个月行神经电生理检测即胫后肌群运动诱发电位,用HE染色、免疫组化染色、透射电镜等方法对移植体远端吻个口再生神经纤维进行形态学观察,并对再生有髓神经纤维的数量、密度、直径及雪旺细胞的密度进行量化分析.结果 移植前新鲜神经组MHC-Ⅱ检测值为72.14±19.88,去细胞组MHC-Ⅱ检测值为4.19±3.11,两组比较差异有统计学意义(t=3.817,P＜0.05);透射电镜观察显示为胶原性管道,无细胞成分.术后4周,处死前行运动诱发电位检测,神经传导速度A组为(21.16±2.31)m/s,B组为(13.37±1.89)m/s,C组为(21.43±2.18)m/s,A组与 C组比较差异无统计学意义(P＞0.05),A组与 B组比较差异有统计学意义(P＜0.05).组织学观察见3组移植体远端吻合口横切面再生神经纤维呈微束状,透射电镜观察再生神经纤维具有正常的形态和结构.A、C组再生神纤纤维数量及直径均优于B组,差异有统计学意义(P＜0.05).结论 经化学萃取的去细胞兔胫神经基膜管能够移植于大鼠,成功修复大鼠坐骨神经缺损,而且复合NGF的去细胞基膜管在神经修复质量上优于单纯的去细胞神经基膜管,更加接近自体神经移植的效果.     

Diagnostic and prognostic value of compound motor action potential of lower limbs in acute paraplegic patients

OBJECTIVES: To evaluate the diagnostic and prognostic contribution of motor nerve conduction studies (NCS) in addition to neurological examination in patients with acute paraplegia. METHODS: In 79 patients with acute onset of paraplegia due to traumatic or ischaemic damage of the conus medullaris/cauda equina (conus/cauda) or lesion of the mid-thoracic spinal cord (epiconal) neurological (initial and follow-up clinical motor and sensory scores; outcome of ambulatory capacity determined at least 6 months post-trauma) and electrophysiological examinations (motor nerve conduction velocity (MNCV) and compound motor action potential (CMAP) of tibial and peroneal nerves) were performed in parallel. RESULTS: Severe axonal motor neuropathies were significantly caused by conus/cauda lesions (loss of tibial CMAP in 71% and of peroneal CMAP in 68%) compared to patients with epiconal lesion (no loss of tibial CMAP and abolished peroneal CMAP in 14%). The CMAPs were deemed acutely pathological 4 - 14 days post-trauma and were indicative of the severity of conus/cauda lesion while the MNCV remained normal. Follow-up recordings (up to 1 year post trauma) revealed no significant change in the CMAP values. The clinical examination according to the American Spinal Injury Association (ASIA protocol) in contrast to the CMAP values was significantly related to the outcome of ambulatory capacity. CONCLUSIONS: In contrast to patients with an epiconal SCI almost all patients with damage of the conus/cauda present a severe axonal neuropathy of the tibial and peroneal nerves. Pathological CMAPs develop as early as 1 - 2 weeks after onset of acute paraplegia. They allow, at an early stage, to differentiate between conus/cauda or epiconal lesion and to assess the severity of conus/cauda lesion. Thereafter follow-up examinations remain stable and a developing worsening of peripheral nerve or spinal cord function, eg due to post-traumatic syringomyelia, may be indicated by a secondary deterioration of CMAP values. The clinical examination, according to the ASIA protocol, in acute paraplegia patients, in contrast to the motor nerve conduction studies, is of prognostic value in predicting the outcome of ambulatory capacity.     

Diaphyseal bone lengthening in children using Wagner device: long-term results

In a series of 32 patients, the tibia was lengthened nine times and the femur 26 times. The lengthening was 4.1 cm in the tibia and 4.9 cm in the femur. The callotasis principle and atraumatic handling of the periosteum were considered important. The leg inequality was corrected appropriately, except in cases where the leg-length inequality was greater than 12 cm as a result of a progressive congenital deformity. Late femoral fractures occurred in six patients, but no tibial fractures were seen. One hip dislocation was seen after femoral lengthening, one talus deformation developed after the tibial lengthening, and one peroneal nerve entrapment was released operatively. One infection caused delayed bone union. Average follow-up time was 5.0 years.     

神经电生理检查对足趾背屈功能障碍的诊断价值

目的 探讨神经电生理检查对无明确外伤史足趾背屈功能障碍的诊断价值.方法 对66例(77侧)无明确外伤史且以足趾背屈功能障碍为主诉的患者行神经电生理检测,内容包括:腓肠神经、腓总神经感觉神经传导速度(sensory nerve conduction velocity,SNCV),胫神经、腓总神经运动神经传导速度(motor nerve conduction velocity,MNCV),胫神经、腓总神经、闭孔神经、臀上神经、臀下神经支配肌及椎旁肌的肌电图(electromyogram,EMG).结果 66例中30例(30侧)腓骨小头处腓总神经卡压,2例(2侧)梨状肌出口处坐骨神经卡压,18例(18侧)神经根处受到腰椎间盘压迫,6例(11侧)累及前角运动神经元病变,6例(10侧)为糖尿病引起的周围神经病变,4例(6侧)所检测指标均在正常范围.神经电生理检测所得结果阳性率为93.9%.结论 神经电生理检查可以为无明确外伤史引起的足趾背屈功能障碍提供客观的检测指标,对该病的病因诊断具有重要的参考价值.