[Current situation and development of Chinese trauma care system].

Trauma has always been a global public health issue and urgently needed to be solved. It has great practical significance for the research of trauma care system. There are two mainstream models of trauma care system in the world. One is the prehospital care represented by the United States and the United Kingdom, which emphasizes rapid transport, and the other is the prehospital care represented by France and Germany, which emphasizes on-site care. The trauma care system was deficient in most developing countries. During the past ten years, rapid progresses have been achieved in trauma care system construction in China which refers to "Chinese regional trauma care system(CRTCS)". CRTCS is established in one administrative region, with one large tertiary hospital as trauma center and five to six secondary hospitals as trauma care sites to form the closed-cycle regional trauma triage and transportation protocols. After several years of construction and implementation, CRTCS is considered to be a feasible new trauma care system in line with the characteristics of China's national conditions, which can significantly shorten the time of trauma treatment and reduce the mortality of trauma. It is worthy of reference for developing countries.

Effect of resistance exercise on peripheral inflammatory biomarkers in healthy adults: a meta-analysis of randomized controlled trials.

OBJECTIVE: This study aimed to evaluate the effect of resistance exercise on peripheral inflammatory biomarkers in healthy adults. MATERIALS AND METHODS: Four databases, including PubMed, Web of Science, Cochrane Library, and SPORTDiscus, were searched from inception until April 1st, 2022. A meta-analysis was conducted using a random-effects model, followed by sensitivity analysis, subgroup analysis, meta-regression analysis, and publication bias analysis. RESULTS: 15 randomized controlled trials were included in the meta-analysis. The pooled results showed that resistance exercise significantly decreased TNF-α levels (SMD = -0.81, 95% CI: -1.42 to -0.20, p = 0.009) but did not affect IL-6 and CRP levels. Individuals with BMI 18.5-24.9 exhibited significantly decreased IL-6 levels, while moderate strength resistance exercise could significantly decrease TNF-α levels. Finally, age might be a confounding factor influencing the effect of resistance exercise on IL-6. CONCLUSIONS: Resistance exercise could reduce TNF-α levels in healthy adults, and resistance exercise with moderate intensity could reduce TNF-α levels more effectively.

[Application of multidisciplinary team (MDT) in the treatment of severe trauma].

OBJECTIVE: To explore the effect of multi-disciplinary team (MDT) in general hospitals on severe trauma patients. METHODS: This study reviewed the treatment of patients with severe trauma in trauma center of Peking University People's Hospital from March 2017 to April 2019. The baseline information: the patients' gender, age, injury mechanism, etc.; the start indicators: the Glasgow coma scale (GCS), trauma index (TI), injury severity score (ISS); the start related indicators: time for activation, time for MDT to arrive, time for CT scan, time for damage control surgery; patient treatment and prognosis: ICU (intensive care unit) length of stay, number of cured and discharged patients, number of dead cases, number of patients transferred to rehabilitation hospital, were all analyzed. It discussed the composition of MDT, the initiation scheme, the indicators of initiation of MDT for severe trauma, and analyzed the correlation between the application of MDT and the prognosis of patients. RESULTS: From March 2017 to April 2019, 112 trauma patients were treated by MDT in Peking University People's Hospital. There were 69 males and 43 females. The minimum age was 15 years, the maximum age was 89 years, most of them were 36-55 years old. The main injury mechanism was traffic accident injury. The GCS, TI, ISS were 13.0±2.9, 13.0±2.8, and 21.5±11.9, respectively. It took 3.7±0.8 minutes to start the call, 6.1±0.9 minutes for MDT personnel to arrive at the emergency rescue area, 23.8±3.0 minutes for fast CT and 92.6±15.4 minutes for injury control operation. All the hospitalized patients were treated effectively. ICU (Intensive care unit) hospitalization time was 12.6±6.7 days. 55 discharged patients were cured, 5 died (1 died of hemorrhagic shock, 4 died of severe brain injury) and 52 transferred to rehabilitation hospital. CONCLUSION: The treatment of severe trauma patients by MDT in trauma center of general hospitals can greatly improve the ability and level of treatment of severe trauma patients, make up for the lack of treatment of severe trauma especially multiple trauma patients in large general hospitals, and improve the treatment effect of severe trauma patients. It provides a reference model for large general hospitals to treat patients with severe trauma and multiple trauma and for the construction of trauma centers.

[Proximal femoral nails antirotation and dynamic hip screws for fixation of unstable intertrochanteric fractures of femur: A meta-analysis].

OBJECTIVE: To evaluate the efficacy and safety of proximal femoral nail antirotation (PFNA) and dynamic hip screw (DHS) for unstable intertrochanteric fractures using meta-analysis. METHODS: The PubMed, Embase, Cocharane Central Register of Controlled Trials, Google Scholar, China Science and Technology Papers and Citation Database (CSTPCD) and China Journal Full-text Database (CNKI) were searched for published randomized controlled trials before January 1, 2019. Two researchers independently screened the literature in the light of the inclusion and exclusion criteria, evaluated the quality of the studies and extracted the data which were consisted of clinical efficacy indexes, such as incision length, operation time,intraoperative blood loss, weight-bearing time,fracture-healing time, Harris hip score and safety indicators like complications. Meta-analysis was performed with the Revman 5.3 software provided by Cochrane Community in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) standard. RESULTS: Nine randomized controlled trials met the requirement with a total of 779 patients, of whom 383 were fixed with PFNA and 396 with DHS. Meta-analysis demonstrated that PFNA was associated with smaller surgical incision length [MD=-7.43, 95%CI (-9.31, -5.55), P<0.05], shorter operation time [MD=-22.76, 95%CI (-29.57, -11.95), P<0.05], less intraoperative blood loss [MD=-216.34, 95%CI (-275.18, - 157.49), P<0.05], earlier weight bearing after surgery [MD=-12.34, 95%CI (-17.71, -6.97), P<0.05], shorter fracture healing time [MD=-5.00, 95%CI (-7.73, -2.26), P<0.05], higher postoperative Harris hip score [MD=12.22, 95%CI (3.88, 20.55), P<0.05], higher rate of excellent Harris hip score [OR=3.56, 95%CI (1.44, 8.81), P<0.05] and lower incidence rate of postoperative complications [OR=0.48, 95%CI (0.33, 0.70), P<0.05], such as hip varus, wound infection, urinary tract infection, pulmonary infection, pressure sore, deep vein thrombosis, pulmonary embolism, heart failure and cerebral infraction when compared with DHS. No statistical difference was shown between the groups when it came to subgroup analysis by age. However, there was no significant difference (P>0.05) in the duration of hospitalization and the complications resulting in the occurrences of internal fixation loosening, such as femoral shaft fracture (during or post operation), internal fixation fracture, cut-out, displacement or retraction. CONCLUSION: Current published evidence supports the superiority of PFNA to DHS for unstable intertrochanteric fractures in terms of clinical efficacy. The conclusion was limited because of the relatively low quality of evidence with low strength of confidence. Large scale and high-quality randomized controlled trials are required to validate the safety of PFNA and DHS for unstable intertrochanteric fractures.

[Correlation analysis between rotator cuff tear and the superior migration of humeral head].

OBJECTIVE: To evaluate the association between rotator cuff tear and the proximal migration of humeral head. METHODS: In this research, we retrospectively selected 30 patients with unilateral rotator cuff tear in Peking University People's Hospital from September 2015 to May 2016, who received magnetic resonance imaging (MRI) and X-ray of the painful shoulder before enrollment in this study, the duration between the two examinations was no longer than 1 week, and also there was no past history of surgery in the selected shoulders. There was no other exclusion criteria. Upward migration index (UMI) was the ratio between the distance of humeral head center to the lower surface of acromion, and the radius of humeral head circle, which could help to minimize the effect of anatomy difference and imaging magnification, compared with the traditional acromiohumeral distance (AHD). Then we introduced this index to stratify the selected 30 patients into 3 groups, and each group contained 10 patients, UMI of group 1 was >1 and ≤1.2, UMI of group 2 was >1.2 and ≤1.4, UMI of group 3 was >1.4. As the supraspinatus was most commonly affected by pathological change among the four rotator cuff tendons, we took it as the research object. Then we used the Spearman correlation analysis to evaluate the relationship between UMI and fatty degeneration, rotator cuff tear size and the thickness of ruptured supraspinatus tendon from X-ray and MRI. RESULTS: In the A-P view, the average UMI was 1.33 (1.02-1.51, SD: ±0.22). UMI and the tear size had a significant negative correlation (R=-0.584, P<0.01), and also there was a negative correlation between the fatty degeneration of the supraspinatus (R=-0.312, P=0.033). However, there was no correlation between UMI and the thickness of ruptured supraspinatus (R=0.127, P=0.071). CONCLUSION: UMI is related with the fatty degeneration of supraspinatus and the tear size. The reduction of UMI is a predictable and reliable mark of rotator cuff tear and degeneration in clinic. Physicians can use physical examination and X-ray first when facing the patients with shoulder pain, which is convenient and helpful for evaluating rotator cuff tears.

["Time-angle measurement" reduction evaluation technique and clinical evaluation of proximal humerus fracture].

OBJECTIVE: To evaluate the functional outcome and the complication rate after open reduction and internal fixation of proximal humeral fractures with a "time-angle measurement" reduction evaluation technique, to assess the acceptance of the fracture reduction and to estimate the result of the sur-gery. METHODS: Forty-six patients [mean age: (66.2±14.9) years] with an acute proximal humeral fracture were managed with open reduction and internal fixation with this reduction evaluation technique from January 2012 to December 2013. According to the Neer classification, there were 6 two- part fractures, 25 three-part fractures and 15 four-part fractures. The functional outcome was evaluated for each patient using the Constant-Murley score; radiographic evaluation was also conducted and complications were recorded. The postoperative shoulder function recovery and imaging findings were followed up to evaluate the guiding significance of this reduction evaluation technique in the clinical treatment of this kind of fracture. RESULTS: In the study, 46 patients had been followed up for 13-36 months, and the average follow-up time was (23.5±7.3) months. All the patients achieved fracture healing 3 months after operation. The average head-shaft angle was (124±3.5) degrees. According to the Constant scoring system, 29 patients (63%) had excellent, 14 patients (30%) had good, and 3 patients (7%) had poor results. The most common complications were pain (7/65) and restricted movement of the shoulder (5/46). There were no cases of screw penetration, necrosis of humeral head, deep tissue infection, nonunion of fracture and axillary nerve injury after operation. CONCLUSION: For appropriate cases of displaced proximal humeral fractures, surgical treatment with application of "time-angle measurement" reduction evaluation technique that was introduced in the present study can lead to a good functional outcome, and the technique of reduction assessment should be regarded as a reasonable reference standard in the treatment of displaced proximal humerus fracture.

[New treatment for peripheral nerve defects: nerve elongation].

Peripheral nerve defects are still a major challenge in clinical practice, and the most commonly used method of treatment for peripheral nerve defects is nerve transplantation, which has certain limitations and shortcomings, so new repair methods and techniques are needed. The peripheral nerve is elongated in limb lengthening surgery without injury, from which we got inspirations and proposed a new method to repair peripheral nerve defects: peripheral nerve elongation. The peripheral nerve could beelongated by a certain percent, but the physiological change and the maximum elongation range were still unknown. This study discussed the endurance, the physiological and pathological change of peripheral nerve elongation in detail, and got a lot of useful data. First, we developed peripheral nerve extender which could match the slow and even extension of peripheral nerve. Then, our animal experiment result confirmed that the peripheral nerve had better endurance for chronic elongation than that of acute elongation and cleared the extensibility of peripheral nerve and the range of repair for peripheral nerve defects. Our result also revealed the histological basis and changed the rule for pathological physiology of peripheral nerve elongation: the most important structure foundation of peripheral nerve elongation was Fontana band, which was the coiling of nerve fibers under the epineurium, so peripheral nerve could be stretched for 8.5%-10.0% without injury because of the Fontana band. We confirmed that peripheral nerve extending technology could have the same repair effect as traditional nerve transplantation through animal experiments. Finally, we compared the clinical outcomes between nerve elongation and performance of the conventional method in the repair of short-distance transection injuries in human elbows, and the post-operative follow-up results demonstrated that early neurological function recovery was better in the nerve elongation group than in the conventional group. On the whole, all of these experimental results revealed the physiological phenomenon of peripheral nerve elongation, and described the physiological change and stretch range in detail. The systematic research results have filled the blank in this field, which is very helpful for clinical limb lengthening surgery, the design of elongation surgery and the evaluation of the peripheral nerve stretch injury. Peripheral nerve elongation will become an innovative treatment technology in repairing peripheral nerve defects.

[Research and promotion of severe trauma rescue standard].

Trauma is a global social problem, with the number of deaths up to 5.8 million all over the world annually. Currently, severe trauma has become the first cause of death in young adults in China. Nowadays, there are many problems in the trauma rescue system, including long pre-hospital transfer period, several secondary transfers, no information exchange between pre-hospital and in-hospital care, and the poor integrated treatment, which results in the situation that the overall treatment level of severe trauma in China is relatively low. In order to solve these problems, we carried out the research and promotion of severe trauma rescue standard, involving completing severe trauma information database, providing local rescue medical workers with standard training, and building up the information system for the linkage and warning of severe trauma. In addition, we developed and promoted the new standard system for severe trauma in 15 cities with 124 medical centers. Due to our research, the treatment ability of severe trauma in the pilot areas was enhanced, and the mortality and morbidity of severe trauma were reduced significantly. To sum up, we had got the expected results after implementing the project.

[Clinical characteristics and risk factors of newly developed vertebral fractures after vertebral augmentation].

OBJECTIVE: To identify the characteristics and risk factors of the refractures after percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP). METHODS: A retrospective analysis of 148 patients who had undergone PKP or PVP between March 2006 and October 2013 in Peking University People's Hospital was conducted. In the study, 29 patients with 42 refractured vertebra and 119 patients without refracture were included. All the patients were observed for a time of (34.4±26.8) months. Clinical, imaging and procedure related factors (gender, age, height, weight, body mass index, the level of the injured vertebra, the time interval between the procedure and the refracture, the level of the refractured vertebra, the bone cement volume injected, performed PKP or PVP,performed unilateral or bilateral, the percentage of anterior vertebral height restoration, the correction of the Cobb angle, cement diffusion, bone mineral density, presence or absence of diabetes mellitus, history of fractures of the whole body, anti-osteoporosis treatment, cement leakage) for each group were analyzed by Cox proportional hazards regression analysis. RESULTS: Of all the patients,16 (55.17%, 16/29) had refractures in the adjacent vertebra, and 13 (44.83%, 13/29) had refractures in the nonadjacent vertebra. Refractures within 3 months accounted for 31.03% (9/29) of all the refractures, and within 1 year accounted for 55.17% (16/29). Both older age (P=0.027, HR=1.051, 95% CI=1.006-1.098) and a history of fractures of the whole body (P=0.012, HR=0.386, 95% CI=0.184-0.812) were statistically significant as the independent risk factors for predicting refractures. Others were not associated with refractures (P>0.05). CONCLUSION: Older age and a history of fractures of the whole body are the independent risk factors of the refractures after PKP and PVP. The mechanism of the refractures after PKP and PVP is mainly the natural development of osteoporosis.

[Applying percutaneous placement of guide wire combined with true lateral view fluoroscopy proximal femoral nail anti-rotation fixation].

OBJECTIVE: To apply modified proximal femoral nail anti-rotation (PFNA) fixation techniques performed by percutaneous placement of guide wire combined with true lateral view and to make the procedures simpler. METHODS: A retrospective study was used to analyze the clinical data of femoral intertrochanteric fractures cases, which were treated with conventional PFNA fixation or modified PFNA fixation performed by percutaneous placement guide wire combined with true lateral view in our hospital, from March, 2011 to May, 2014. In the study, 60 cases were followed for average 13 months. The operation time, the amount of bleeding, the fluoroscopy time, postoperative radiographic measurements (tip apex distance, TAD) and hip function scores were analyzed. RESULTS: In modified PFNA group, the amount of bleeding, the operation time and the fluoroscopy time were (34.9±6.1) mL, (70.5±12.5) min, (63.6±9.7) s respectively. In conventional PFNA group,they were (47.8±6.7) mL, (80.6±17.1) min, (68.5±8.7) s respectively. There were significant differences in the above respects between the two groups (P were 0.006, 0.013, and 0.022 respectively). There were no significant differences in TAD, fracture healing time, postoperative hip scores between the two groups (P>0.05). CONCLUSION: Fracture line is a natural entry point for some cases of femoral intertrochanteric fractures when we use proximal femoral nail anti-rotation to fix the fracture. Applying percutaneous insertion of the guide pin combined with true lateral view could reduce the operation time, amount of bleeding, and fluoroscopy time significantly, make the procedures simpler and acquire satisfactory results .

[Evaluation of the use of structure screw in PHILOS plate for treatment of proximal humerus fracture in Chinese].

OBJECTIVE: To measure vertical axis length of humerus head in patients with proximal humeral fractures and to evaluate the use of structure screws in proximal humerus internal locking osteosynthesis system (PHILOS). METHODS: From January 2007 to February 2014,117 patients with proximal humerus fracture were treated by PHILOS plate. Preoperatively, all the patients tookanteroposterior X-ray of shoulder, and the vertical axis length of humerus head were measured, and the use of structure screws in PHILOS plate was observed. RESULTS: There were 40 male and 77 female patients; The vertical axis length of humerus head in male patients was (47.64±3.44) mm, and the rate of structure screw use was 52.5%; The vertical axis length of humerus head in female patients was (42.46±3.21) mm, and the rate of structure screw use was 32.5%. The vertical axis length of humerus head and the rate of structure screw use had significant difference in the male and female groups (P<0.05). CONCLUSION: The rate of structure screw use was low in the treatment of proximal humerus fracture by PHILOS plate, especially for women. We should improve the design of plate according to the anatomical characteristics of Chinese.

[Characteristics and perioperative management of hemophilia patients with fractures].

OBJECTIVE: To investigate the characteristics and perioperative management of hemophilia patients with fracture. METHODS: Retrospectively, we analyzed 8 patients with hemophilia combined with fracture, who were admittted to our department from 2005 to 2013. Six patients were with hemophilia A and two with hemophilia B; Based on the severity of hemophilia, 2 cases were light, 3 moderate and 3 severe; Based on the location of fracture, 4 cases were femoral neck fractures, 1 femoral intertrochanteric fracture, 1 bilateral distal femur fractures, 1 tibiofibula fracture, and 1 humerus intercondylar fracture. Blood coagulation factor replacement therapy was conducted preoperatively, intraoperatively and postoperatively, All the patients underwent closed or open reduction and internal fixation or joint replacement. Also, we analyzed the perioperative complications and observed whether the fracture healed. RESULTS: The average age was 33.5 years (14 to 47 years); In 6 cases, fractures occurred at femur, accounting for 75% of all the fractures; Femoral neck fracture was treated by closed reduction and hollow screws fixation; Femoral intertrochanteric fracture, distal femur fracture, and tibiofibula fracture were treated by open reduction and internal fixation with plate; Humerus intercondylar fracture was treated by elbow joint replacement. Intraoperative bleeding was from 50 to 600 mL, an average of 262 mL; Perioperatively, the average use of FVIII/activated prothrombin complex concentrates (APCC) was 358 U/kg (125 to 554 U/kg). Postoperatively, poor wound healing was observed in 2 patients, and the condition improved after symptomatic treatment; In patients with internal fixation, all the fractures united, and the average healing time was 14 weeks. No complications such as fixation loosening or rupture occurred after internal fixation. CONCLUSION: Hemophilia combined with fracture mainly occurred in the young, and the site of fracture was given priority to femur. With perfect preoperative preparation, on the basis of the replacement therapy, hemophilia combined with fractures was safe for surgical treatment, and postoperative fractures healing wasgood. But the risk of poor wound healing was high.

Radiological evaluation of reduction loss in unstable proximal humeral fractures treated with locking plates.

PURPOSE: The aim of this study was to radiologically evaluate the risk of reduction loss after locking plate fixation of proximal humerus fractures. METHODS: From September 2007 to April 2009, 71 patients (28 males, 43 females) with unstable proximal humeral fracture were treated with open reduction and internal fixation by locking plate. The mean follow-up time was 31.2 months (range: 26-47). The head-shaft angulation (HSA) and the humeral head height (HHH) in true anteroposterior (AP) were recorded and compared over time. All complications were noted. Shoulder function was measured by the Constant score. RESULTS: Patients with ΔHSA >10° (t=2.740, P=0.008) and ΔHHH >5mm (t=2.55, P=0.019) were more likely to have impaired shoulder function. Varus collapse occurred most frequently in patients with initial reduction of HSA <125° (χ(2)=19.17, P<0.001, Fisher's exact test F<0.001). Patients with >5mm HHH decrease were strongly associated with loss of reduction (χ(2)=24.23, P<0.001, F<0.001). CONCLUSIONS: Dynamic change of HSA >10° and HHH >5mm were radiological factors that indicated poor shoulder function. Intra-operative HSA >125° should be achieved to avoid reduction loss following locking plate fixation of proximal humerus fracture. LEVEL OF EVIDENCE: level IV.

Lyme borreliosis caused by diverse genospecies of Borrelia burgdorferi sensu lato in northeastern China.

The variety of Borrelia burgdorferi sensu lato (B. burgdorferi) genospecies leads to distinction in clinical manifestations of Lyme borreliosis (LB). There are reports of LB clinical characteristics in China, where the B. burgdorferi genospecies in ticks and animal hosts are different from those in Europe and North America. During May to September in 2010 and 2011, all patients who had erythema migrans (EM, more than 5 cm in diameter) after a recent tick-bite, and sought medical care at Mudanjiang Forestry Central Hospital, Heilongjiang Province of northeastern China, were enrolled in the study. Specific PCR was used to determine the B. burgdorferi genospecies in the disseminated patients. Of 265 EM patients, B. burgdorferi DNA was detected in blood specimens from 15 of 55 disseminated patients. Sequence analyses of 5S-23S rRNA, flagellin, ospC, 16S rRNA and ospA genes revealed that 11 patients were infected with Borrelia garinii, three with Borrelia afzelii and one with Borrelia valaisiana-related genospecies. Among 15 patients, 40%, 13.3% and 13.3% manifested pruritus, pain and ulceration, respectively. Systemic symptoms, arthralgia or a swollen joint and lymphadenopathy were observed in 26.7%, 13.3% and 6.7% patients, respectively. In northeastern China, three genospecies of LB patients were detected. The B. burgdorferi genospecies identified in this study was predominantly B. garinii. A case infected with B. valaisiana-related genospecies was reported for the first time.

[A study of genetic character of cultivar Shiyuan 321 from G. barbadense x G. thurberi x G. hirsutum using isozyme and RAPD techniques].

To study the genetic character of trispecific hybrid cultivar Shiyuan 321, we analyzed this cultivar and its parents by isozyme and RAPD techniques. The main results are as follows: (1) Esterase isozyme analysis showed that there was one specific band among cultivar Suiyuan 321 and its parents, G. thurberi and G. barbadense; (2) Six specific DNA fragments amplified by 4 primers were found among cultivar Shiyuan 321 and its parents G. barbadense, G. thurberi; (3) By comparing RAPD differences among Shiyuan 321 and its parents, it is indicated that the genetic heterogeneity of cultivar Shiyuan 321 is very high at its genomic DNA level. The above results proved that Shiyuan 321 is a trispecific cultivar from G. barbadense x G. thurberi x G. hirsutum as well as a new germplasm.

[Genetic improvement of cotton varieties in Huang-Huai region in China since 1950's. III. Improvement on agronomy properties, disease resistance and stability].

Data from a set of 5-location and 2-year experiments on 10 representative historical cotton varieties and the data of Huang-Huai Regional Cotton Trials from 1973 to 1996 were analyzed to estimate the effects of genetic improvement in agronomy properties, disease resistance and stability of cotton in Huang-Huai Region in China. The results indicated that a great genetic progress of earliness and disease resistance had been achieved by breeding programs since 1950's. The maturity was shortened 3-5 days; The rate of preforst yield was increased about 7 percentages. The problem of resistance to Fususium wilt has been solved and the resistance to Verticillum wilt was improving. Some progress in stability of cotton varieties also has been achieved by breeding programs since 1950.

[Experimental study of peripheral nerve expansion with a tissue expander].

If a peripheral nerve could be elongated by a tissue expander (TE) without apparent damage, the length gained could be used to overcome a nerve gap without recourse to nerve graft. An experimental study was made to investigate whether this method for repairing a nerve gap is feasible. The tissue expander was designed by the authors and the median nerve of rabbits were stretched with TE at the rate of about 1 mm/day. The results showed that when the elongation rate was 18.4%, the motor nerve conduction velocity (MCV) was 67.8% and the myelinated nerve fibres (MNF) was 82.9% of the control nerves. In a further study nerve grafting and nerve expansion for repairing segmental nerve loss were compared with 10 mm defects. 4 months later the MCV, MNF, isometric contraction force (ICF) and muscle wet weight (MWW) were not significantly different between the 2 techniques. But with the 15 mm defects, elongated nerve were inferior to the nerve grafting method.