Electron Microscopic Study in the Rat Model of Electrically Injured Myelopathy: Preliminary Report

Objective

The patient with electrically injured myelopathy showed mild motor weakness without somatosensory pathway abnormalities. Few reports have been reported on the pathophysiological mechanisms of electrically injured myelopathy, and there is controversy about the exact pathological causes. This study aimed to investigate the ultrastructural changes in the electron microscopic findings of electrical spinal cord injury.

Methods

Nine rats were used in this study. We performed 7 electrical shocks (frequency, 120 Hz; pulse width, 0.9 ms; duration, 3 seconds; current, 99 mA) using an electroconvulsive therapy (ECT) apparatus (57800 ECT unit; UGO BASILE). We used one ear and one contralateral hind limb as entry and exit sites, respectively. We only enrolled rats with hind limb weakness and performed electron microscopy evaluations of the spinal cord on the first day and 4 weeks after injury.

Results

On the first day after injury, an electron microscopic examination showed a directly damaged area that appeared to be torn as physical damage, damaged myelin sheath, vacuolated axons in the myelin sheath, swollen Golgi apparatus, and injured mitochondria. Looking at changes in motor and sensory nerves, the sensory neurons showed recovered mitochondria and Golgi apparatus 4 weeks after injury; however, motor neurons still showed injured mitochondria, swollen Golgi apparatus, and endoplasmic reticulum.

Conclusion

This study showed that recovery from ultrastructural injury was more rapid in sensory neurons than in motor neurons.

[Imaging judgment of soft tissue and vascular injuries in limbs with high-voltage electric burn and its clinical significance]

The injury mechanism of high-voltage electric burn in limbs is complex and special. The soft tissue and vascular injuries caused by high-voltage electric burn are serious and concealed. It is difficult to judge the severity and extent of injury before surgery, which affects the diagnosis and treatment effects and remains a major problem in burn field. In recent decades, a series of clinical studies have been conducted by scholars at home and abroad, using various imaging methods for the judgment of soft tissue and vascular injuries, which have their own advantages and disadvantages. According to the principle of accuracy, precision, safety, and easy operation, magnetic resonance imaging and magnetic resonance angiography are required at the same time in general for the imaging judgment of soft tissue and vascular injuries in limbs with high-voltage electric burn. The B-mode ultrasonography shall be performed if a precise judgment of vascular injury is needed.

[Clinical effect of free anterolateral thigh flap combined with arterial vascular reconstruction on repairing high-voltage electrical burn wound on the wrist]

Objective: To explore the clinical effect of free anterolateral thigh flap combined with arterial vascular reconstruction on repairing high-voltage electrical burn wound of type Ⅱ and Ⅲ on the wrist. Methods: From May 2016 to February 2019, 25 patients with deep high-voltage electrical burn wounds on the wrist were admitted to Zhengzhou First People's Hospital, including 23 males and 2 females, aged 11-63 years. Among them, 4 cases had bilateral electrical burns on the wrist, and 21 cases had unilateral electrical burns on the wrist. There were 29 wounds in 29 affected limbs with depth of full-thickness to full-thickness with tendon and bone exposure, and 17 wounds were type Ⅱ and 12 wounds were type Ⅲ. Twenty-four patients underwent CT angiography of the upper extremities before surgery, while the other one patient did not undergo the examination due to seafood allergy. There were no obvious injury to the ulnar and radial arteries in 7 affected limbs, simple ulnar artery injury in 6 affected limbs, simple radial artery injury in 7 affected limbs, and both ulnar and radial arteries injury in 9 affected limbs. The wound areas after debridement were 10 cm×7 cm-36 cm×17 cm, and the free anterolateral thigh flaps were obtained with area of 11 cm×8 cm-37 cm×18 cm for repairing the wounds. For patients with no damage of ulnar artery and radial artery, the trunk of descending branch of lateral circumflex femoral artery of the flap or combined with the thick muscle perforating branch or lateral branch was anastomosed with the ulnar or radial artery of the wound. For patients with simple ulnar artery or radial artery injury, the trunk, lateral branch, or medial branch was anastomosed with the ulnar artery or radial artery of the wound. For patients with long injury of ulnar artery and radial artery, the ulnar artery or radial artery of the wound was reconstructed with one of the above-mentioned methods, the injured artery that was not anastomosed was reconstructed with great saphenous vein, and the transplanted blood vessel was embedded in the lateral femoral muscle. The accompanying vein of the descending branch of the lateral circumflex femoral artery of the flap was anastomosed with the accompanying vein of the ulnar artery or radial artery of the wound and/or the cephalic vein. The donor sites of flaps were sutured directly or repaired with split-thickness skin graft from the thigh. The survival condition of flap and affected limb after operation and during follow-up was observed, and hand function of the affected limb during follow-up was evaluated according to the evaluation standard after repair of peripheral nerve injury in upper limbs. Results: Fifteen affected limb wounds had tissue liquefaction but healed after second debridement on 14-28 days after flap repair operation. All 29 flaps survived in the end. One patient had long ulnar artery and radial artery injuries in affected limbs and the hand was necrotic due to second embolism of the blood vessel in 1 week post operation, and the remaining affected limbs survived. During the follow-up of 6 to 30 months after operation, the flaps were slightly bloated, the affected limbs were warm with normal blood flow, and finger flexion, wrist flexion, and sensory function of hand recovered to varying degrees. The functions of the survived affected limbs were evaluated as excellent in 8 affected limbs, good in 9 affected limbs, medium in 5 affected limbs, and poor in 6 affected limbs, with an excellent and good rate of 60.71%. Conclusions: The clinical effect of free anterolateral thigh flap combined with arterial vascular reconstruction is good for repairing high-voltage electrical burn wound on the wrist, and the patency restoration of the ulnar artery and/or radial artery of the upper limb in stage Ⅰ is helpful for improving the success rate of limb salvage.

[Epidemiological investigation of 169 inpatients with high-voltage electrical burns on the wrist]

Objective: To analyze the epidemiological characteristics of inpatients with high-voltage electrical burns on the wrist in Beijing Jishuitan Hospital (hereinafter referred to as the author's unit), so as to provide reference for the prevention and treatment of high-voltage electrical burns on the wrist. Methods: The medical records of inpatients suffered from high-voltage electrical burns on the wrist in the author's unit from January 2008 to December 2019 were collected. The patients' gender, age, population category, injury situation, injury season, total burn area, electrical burn type on the wrist of the affected limbs, the time from injury to first flap/myocutaneous flap transplantation, vascular reconstruction and flap/myocutaneous flap transplantation of the affected limbs, the total amputation rate of the affected limbs and the amputation rate of the affected limbs with type Ⅲelectrical burns on the wrist, the number of operation, postoperative infection rate of flap/myocutaneous flap, length of hospital stay, hospitalization expense, and treatment outcome were retrospectively analyzed. Comparison of the aforementioned statistical items between patients admitted from January 2008 to December 2013 (hereinafter referred to as the pre-stage) and January 2014 to December 2019 (hereinafter referred to as the post-stage) except gender, the total amputation rate of the affected limbs, treatment outcome were performed. Data were statistically analyzed with chi-square test, Fisher's exact probability test, and Wilcoxon rank-sum test. Results: During the 12 years, a total of 169 patients with high-voltage electrical burns on the wrist were admitted to the author's unit, including 162 males and 7 females, aged (35±13) years, and 75.15% (127/169) of patients were 21-50 years old. The top three groups in population category from high to low were workers, migrant workers, and primary and secondary school students, accounting for 48.52% (82/169), 28.99% (49/169), and 9.47% (16/169), respectively. At work of non-electric power accounted for 47.93% (81/169) and ranked the first in the proportion of injury situation. The injury occurred mostly in summer and autumn, accounting for 39.05% (66/169) and 28.99% (49/169), respectively. About 65.09% (110/169) of the patients were with total burn area less than 10% total body surface area. There were totally 216 affected limbs with high-voltage electrical burns on the wrist, of which the numbers of wrist with type Ⅲ and type Ⅳ injury were 25 (11.57%) and 21 (9.72%), respectively. The time from injury to first flap/myocutaneous flap transplantation was 6.00 (3.75, 8.00) d. There were 45 affected limbs operated with vascular reconstruction, 75 affected limbs transplanted with pedicled axial flap, and 86 affected limbs transplanted with free flap/myocutaneous flap. The total amputation rate of affected limbs was 12.96% (28/216), and the amputation rate of the affected limbs with type Ⅲ electrical burns on the wrist was 28% (7/25). The number of operation was 4 (3, 5) times, the postoperative infection rate of flap/myocutaneous flap was 7.18% (13/181), the hospitalization time was 39.00 (25.00, 50.00) d, and the hospitalization cost was 123 553.00 (50 656.50, 216 003.00) yuan. Compared with those of the pre-stage, the time from injury to first flap/myocutaneous flap transplantation was significantly shortened (Z=-4.038, P<0.01), the ratio of free flap/myocutaneous flap transplantation on affected limbs was significantly increased (χ(2)=13.478, P<0.01), the ratio of pedicled axial flap transplantation on affected limbs was significantly decreased (χ(2)=10.242, P<0.01), the number of operation was significantly reduced (Z=-5.903, P<0.01), the postoperative infection rate of flap/myocutaneous flap was significantly decreased (χ(2)=4.492, P<0.05), the length of hospital stay was significantly shortened (Z=-2.723, P<0.01), and the hospitalization expense was significantly decreased among patients hospitalized in the post-stage (Z=-2.121, P<0.05). The other items were close between patients hospitalized in the pre-stage and those in the post-stage. Conclusions: Men were more likely than women to suffer from high-voltage electrical burns on the wrist in the author's unit. Young workers and migrant workers may be the key groups for the prevention of high-voltage electrical burns on the wrist. It is very important to strengthen the management of high voltage safety education for non-electric power staff, warn and protect the surrounding area of high voltage environment, and prohibit non staff for entering the high voltage environment, especially in summer and autumn. In the last 6 years, the patients with high-voltage electrical burns on the wrist may benefit from the active vascular reconstruction at early stage and free flap/myocutaneous flap repair in the author's unit.

[Impacts of high-voltage electrical burn on serum platelet-related factors and platelet aggregation number in rats and the interventive effect of Xuebijing]

Objective: To explore the effect of high-voltage electrical burn on platelet function and rheological behavior in rats and the interventive effect of Xuebijing. Methods: A total of 280 Sprague Dawley rats of clean grade (aged 8-10 weeks, male and female unlimited) were divided into sham injury group, simple electrical burn group, electrical burn+ saline group, and electrical burn+ Xuebijing group according to the random number table, with 70 rats in each group. Rats in sham injury group were not conducted with electrical current to cause sham injury. Rats in the other three groups were given electrical current with output voltage of 2 kV and current intensity of (1.92 ± 0.24) A for 3 s, which caused high-voltage electrical burn wounds, each with an area of 1 cm×1 cm distributed in the left forelimb at the current inlet and the right hindlimb at the current outlet respectively. Rats in sham injury group and simple electrical burn group were not treated after injury. At post injury minute 2 and on post injury day (PID) 1, 2, 3, 4, 5, and 6, rats in electrical burn+ saline group and electrical burn+ Xuebijing group were intraperitoneally injected with 6 mL/kg saline and 6 mL/kg Xuebijing, respectively. Survival conditions of rats were recorded during the experiment. At 15 min before injury and at post injury hour (PIH) 1, 8, 24, 48, 72, and on PID 7, 10 rats in each group were respectively selected according to the random number table to sacrifice after collection of 5 mL blood under the direct vision of heart. Blood in the volume of 0.05 mL from each rat was taken to make blood smear, and platelet aggregation number was counted under 400 fold field of view using multiple projection microscope. The remaining blood samples were centrifuged to collect supernatant, and the content of platelet-derived growth factor (PDGF), thrombopoietin (TPO), and platelet activating factor (PAF) was detected by enzyme-linked immunosorbent assay. Data were statistically analyzed with analysis of variance for factorial design and Student-Newman-Keuls method. Results: All rats in sham injury group and simple electrical burn group survived during the experiment. One rat in electrical burn+ saline group died on PID 6, and one rat on PID 5 and one rat on PID 6 died in electrical burn+ Xuebijing group. The levels of all indexes among the 4 groups were close at 15 min before injury. The serum content of PDGF, TPO, and PAF and platelet aggregation number of rats in the three electrical burn groups at all time points after injury were higher or more than those in sham injury group, and the first three indexes reached the peak at PIH 8. The serum platelet aggregation number of rats in simple electrical burn group reached the peak at PIH 48, and that in electrical burn+ saline group and electrical burn+ Xuebijing group reached the peak at PIH 72. Among them, the serum content of PDGF of rats in electrical burn+ Xuebijing group at PIH 48, 72 and on PID 7 ((12.8±4.0), (11.6±4.4), (11.0±3.6) ng/mL, respectively) was close to that in sham injury group ((10.4±2.0), (10.4±2.5), (9.8±3.3) ng/mL, respectively, P>0.05). The serum content of TPO of rats in electrical burn+ Xuebijing group at PIH 24, 72 and on PID 7 ((200±52), (192±36), (193±32) ng/mL, respectively) was close to that in sham injury group ((182±30) , (184±41), (183±33) ng/mL, respectively, P>0.05). The serum content of PDGF, TPO, and PAF and platelet aggregation number of rats in electrical burn+ Xuebijing group at every time point after injury was generally lower or less than that in electrical burn+ saline group and simple electrical burn group. Conclusions: Application of Xuebijing treatment after high-voltage electrical burn can decrease the content of PDGF, TPO, and PAF in the serum and reduce the number of platelet aggregation, thereby inhibit platelet activation and improve platelet rheology.

[Focus on mental disorders induced by electrical burns]

Electrical burn is a special type of injury with complex injury mechanism, which is one of the difficult issues in the treatment of burn injuries. It not only seriously damages the tissue and organs of body, but also significantly affects the mental health of patients. Many patients with electrical burn simultaneously suffer physical and mental agonies causing increased difficulty in treatment and prolonging the time of recovery. Some of them may experience loss of ability to work or even death due to the mental disorders, despite successful patch-up of their physical injuries. Therefore in treating electrical burn, the psychotherapy and rehabilitation of patients should be closely monitored in addition to the reconstruction of their physical damage.

[Strengthen standardized diagnosis and treatment to improve the prognosis of electric burn]

Because of the complex injury mechanism, hidden tissue injury, and severe systemic injury, the clinical diagnosis and treatment of electric burn still face many challenges, and the mortality and disability rate are still high. In view of the particularity of electric burn and the prognosis of electric burn, especially the quality of wound repair, the author puts forward some personal views on fluid resuscitation, organ protection, and wound repair on the basis of summarizing the new methods of diagnosis and treatment of electric burn at home and abroad at present, and preliminarily explores the standardized diagnosis and treatment of electric burn.

[Application of low temperature thermoplastic plate combined with special abdominal band in fixing abdominal pedicled flap for repairing 17 patients with deep electric burn wounds in hands]

If the abdominal pedicled flaps are not well fixed after repair of deep electric burn wounds in hands, many problems such as poor blood supply may occur. In order to solve the above problems, we designed and manufactured the individualized low temperature thermoplastic plate combined with special abdominal band to fix abdominal pedicled flaps for repairing of 17 patients (12 males and 5 females, aged 2-35 years) with deep electric burn wounds in hands from February 2016 to August 2018, and achieved the desired results. The shoulder joint, elbow joint, and wrist joint were fixed by low temperature thermoplastic plate according to the 1/2 circumference of the patient's side chest and upper arm, and the braking of wrist joint and elbow joint was strengthened by special abdominal band. Application of the combined method of fixing abdominal pedicled flaps in repairing deep electric burn wounds in hands has high success rate of flap transplantation. It is simple to make and practical, and worthy of clinical promotion.

[Clinical characteristics and repair effect of 136 patients with electric burns of upper limb]

Objective: To analyze clinical characteristics and wound repair methods and effects of patients with upper limb electric burns. Methods: Medical records of 136 patients with upper limb electric burn who met the inclusion criteria and hospitalized in our unit from January 2015 to March 2019 were retrospectively analyzed. Proportion in patients with electric burns in the same period, gender, age, admission time, categories, injury causes, injury voltage, burn area and depth of upper limb, simultaneous injury of both upper limbs, and early wound treatment measure of patients with upper limb electric burn were recorded. The main repair methods of each affected limb were classified and recorded. The overall efficacy of the patients was recorded, including postoperative wound complications and healing condition. The patients repaired with distal pedicled flaps and those with free flaps were followed up for 3 to 6 months. The survival rate of flaps were recorded, the function of affected limbs after operation was evaluated, and the satisfaction degree of patients was investigated by Curative Effect Score Table. The amputation rate, age, and burn area of upper limbs of patients caused by high-voltage and low-voltage electricity were compared. Data were processed with Wilcoxon rank sum test, chi-square test, or Fisher's exact probability test. Results: (1) The number of upper limb electric burn patients accounted for 88.3% of 154 patients with electric burns hospitalized in the same period, including 117 males and 19 females, aged 1 year and 2 months to 72 years [(34±18) years], admitted 1 h to 48 d after injury, including 51 electricians, 32 rural migrant workers, 31 students and preschool children, and 22 patients belonging to other categories. Patients of the first two categories were mainly injured by work accidents, and those of the latter two categories mainly suffered from touching power source or power leakage. Among all the patients, 75 cases were injured by high-voltage electric burn, and 61 cases were injured by low-voltage electric burn, with burn area of upper limb from 0.2% to 16.0% [2% (1%, 5%)] total body surface area (TBSA) and area of wounds deep to bone from 0.2% to 15.0% [2% (1%, 5%)] TBSA. Two upper limbs in 54 cases were simultaneously injured, accounting for 39.7%. Early fasciotomy was performed for 73 limbs. (2) Thirteen affected limbs were treated with dressing change, 2 affected limbs were sutured directly after debridement, 56 affected limbs were repaired by skin grafting, 12 affected limbs were repaired by local flap, 45 affected limbs were repaired by distal pedicled flap, 22 affected limbs were repaired by free flap, and 40 affected limbs were amputated (accounting for 21.1%). (3) One case died of pulmonary infection, sepsis, and multiple organ failure after operation, and the rest patients were all cured. One case with avulsion of abdominal flap was repaired by skin grafting after dressing change. The anterolateral thigh flap in one case necrotized after transplantation, which was replaced by pedicled abdominal flap. Seven cases had small erosion on the pedicle or margin after transplantation of abdominal flap and were healed by dressing change. Six cases had local bruising at the distal end after transplantation of abdominal flap and were healed after conservative treatment such as hyperbaric oxygen. The other flaps survived well. (4) The survival rate of distal pedicled flap grafting was 97.8% (44/45), which was close to that of free flap grafting (95.5%, 21/22, P>0.05). The function recovery of affected limb after free flap grafting was better than that of distal pedicled flap grafting (Z=-3.054, P<0.01), but their satisfaction degree of patients was similar (Z=-0.474, P>0.05). (5) Patients with high-voltage electric burn had higher amputation rate, older age, and larger upper limb burn area than those with low-voltage electric burn (χ(2)=4.743, Z=-2.801, -6.469, P<0.05 or P<0.01). Conclusions: Upper extremity electric burn often occurs in children, electricians, and rural migrant workers with high rate of amputation. Teachers and parents should strengthen safety education for children and manage power source of life well. Workers should improve safety awareness and operate standardly. Fasciotomy for relaxation should be performed for electric burn wound as soon as possible, and flap grafting can effectively repair wound after early debridement. The function recovery of affected upper limb repaired with free flap grafting is better.

[Limb salvage strategies for patients with high voltage electric burns of extremities on the verge of amputation]

Objective: To explore the limb salvage strategies for patients with high voltage electric burns of extremities on the verge of amputation. Methods: From January 2003 to March 2019, 61 patients with high voltage electric burns of extremities on the verge of amputation were treated in our hospital. All of them were male, aged 15-58 years, including 49 cases of upper limbs and 12 cases of lower limbs. The wound area after thorough debridement ranged from 15 cm×11 cm to 35 cm×20 cm. Emergency surgery for reconstruction of the radial artery with saphenous vein graft under eschar was performed in 5 cases. The arteries of 36 patients (including 7 cases with simultaneous ulnar artery and radial artery reconstruction) were reconstructed with various forms of blood flow-through after debridement, among them, the radial artery of 13 cases, the ulnar artery of 8 cases, the brachial artery of 8 cases, and the femoral artery of 2 cases were reconstructed with saphenous vein graft; the radial artery of 3 cases and the ulnar artery of 7 cases were reconstructed with the descending branch of the lateral circumflex femoral artery graft; the radial artery of 2 cases were reconstructed with greater omentum vascular graft; the reflux vein of 3 cases with wrist and forearm annular electric burns were reconstructed with saphenous vein graft. According to the actual situation of the patients, 12 cases of latissimus dorsi myocutaneous flap, 6 cases of paraumbilical flap, 28 cases of anterolateral thigh flap, 10 cases of abdominal combined axial flap, 5 cases of greater omentum combined with flap and/or skin grafts were used to repair the wounds after debridement and cover the main wounds as much as possible. Some cases were filled with muscle flap in deep defect at the same time. The area of tissue flaps ranged from 10 cm×10 cm to 38 cm×22 cm. For particularly large wounds and annular wounds, the latissimus dorsi myocutaneous flap, the paraumbilical flap, the abdominal combined axial flap, and the greater omentum combined with flap and/or skin grafts were used more often. Donor sites of three patients were closed directly, and those of 58 patients were repaired with thin and medium split-thickness skin or mesh skin grafts. The outcome of limb salvage, flap survival, and follow-up of patients in this group were recorded. Results: All the transplanted tissue flaps survived in 61 patients. Fifty-six patients had successful limb salvage, among them, 31 limbs were healed after primary surgery; 20 limbs with flap infection and tissue necrosis survived after debridement and flap sutured in situ; 5 limbs with flap infection, radial artery thrombosis, and hand blood supply crisis survived after debridement and radial artery reconstruction with saphenous vein graft. Five patients had limb salvage failure, among them, 3 patients with wrist electric burns had embolism on the distal end of the transplanted blood vessels, without condition of re-anastomosis, and the hands gradually necrotized; although the upper limb of one patient was salvaged at first, due to the extensive necrosis and infection at the distal radius and ulna and the existence of hand blood supply under flap, considering prognostic function and economic benefits, amputation was required by the patient; although the foot of one patient was salvaged at first, due to the repeated infection, sinus formation, extensive bone necrosis of foot under flap, dullness of sole and dysfunction in walking for a long time, amputation was required by the patient. During the follow-up of 6 months to 5 years, 56 patients had adequate blood supply in the salvaged limbs, satisfied appearance of flaps, and certain recovery of limb function. Conclusions: Timely revascularization, early thorough debridement, and transplantation of large free tissue flap, combined tissue flap, or blood flow-through flap with rich blood supply are the basic factors to get better limb preservation and recovery of certain functions for patients with high voltage electric burns of limbs on the verge of amputation.

[Clinical application of lobulated transplantation of free anterolateral thigh perforator flap in the treatment of electric burns of limbs]

Objective: To explore the clinical efficacy of lobulated transplantation of free anterolateral thigh perforator flap in repairing electric burn wounds of limbs. Methods: From August 2014 to April 2019, 19 patients with electric burns in the limbs were hospitalized in our unit, including 18 males and 1 female, aged 20-58 years. There were 37 wounds deep to bone. The area of wounds ranged from 3.0 cm×2.0 cm to 40.0 cm×8.0 cm. Multiple-perforator-based anterolateral thigh flap was designed and resected. Then the flap was lobulated taking the respective perforators of the lateral circumflex femoral artery as the axial vessels before being transplanted to the debrided wounds in the limbs. The blood vessel trunk or the perforator vessels of flap lobes were anastomosed with the respective vessels in the recipient sites. The wounds were repaired with respective lobes of the flap when repairing multiple wounds in one surgical procedure, whereas the lobes were spliced or staggered to cover the wound to fit the shape of wound when repairing a single irregular wound in one surgical procedure. For the limb with distal blood supply disorder, the blood supply branch of flap was used to reconstruct the blood supply. If necessary, an appropriate length of vein was taken for transplantation. The improvement of reconstructed blood supply was observed. The number of surgeries, the number of anterolateral thigh perforator flaps, the number and size of flap lobes, the number of anastomosed vessels in each surgery, the treatment of the donor sites, the length of each surgery, the postoperative complications and survival condition of flap lobes were recorded. The upper extremity function was evaluated with the Carroll's Upper Extremity Function Test Scale, and the patients' satisfaction degree with the therapeutic effect of each surgery was investigated with a 5-point Likert Scale during follow-up. Surgeries were divided into single wound group of repairing one wound at one time and multiple wounds group of repairing two or more wounds at one time. The number of anastomosed vessels in each surgery, the treatment of the donor sites, the length of each surgery, and the postoperative survival condition of the flap lobes were compared between the two groups. Surgeries were divided into early group of performing surgery within post burn day 7 and late group of performing surgery on post burn day 7 and beyond. The postoperative complications and survival condition of flap lobes, the evaluation score of upper limb function and the patients' satisfaction degree with the therapeutic effect of each surgery at the last follow-up were compared between the two groups. Data were processed with independent sample t test, Mann-Whitney U test, or Fisher's exact probability test. Results: The blood supply of 5 patients with distal hand or finger blood supply disorder recovered or improved significantly after vascular transplantation. A total of 46 lobes [(2.2±0.4) lobes per flap] were obtained from 21 anterolateral thigh perforator flaps in 19 patients with 21 surgeries. The area of flap lobes ranged from 4.0 cm×3.0 cm to 24.0 cm×13.0 cm. In each surgery, 2.0 (1.5, 3.0) arteries and 3.0 (2.0, 3.0) veins were anastomosed. Six donor sites were repaired by thin split-thickness scalp, and 15 donor sites were closed directly. The duration of each surgery was (8.9±1.7) h. After surgery, bleeding and hematoma occurred in 2 flap lobes and local infection occurred in 5 flap lobes, which were improved after management. Vascular crisis occurred in 4 flap lobes, and exploratory surgeries were performed, after which 2 lobes survived, while the other 2 lobes necrotized and were repaired by other methods. The rest flap lobes survived well. After each postoperative follow-up of 3 to 60 months, the flap covering areas of the limbs were well-recovered. At the last follow-up, the function evaluation score of 20 affected upper limbs was 85 (63, 90) points, and the score of patients' satisfaction degree with the therapeutic effect of each surgery was (4.4±0.7) points. A total of 30 flap lobes were obtained in 14 surgeries and repaired 30 wounds respectively in multiple wounds group, and 16 flap lobes were obtained in 7 surgeries and were spliced to repair 7 large irregular wounds in single wound group. There were no statistically significant differences in the number of anastomosed artery or vein in each surgery, and the duration of each surgery between multiple wounds group and single wound group (Z=0.240, 0.081, t=0.180, P>0.05), and the condition of skin grafting in the donor sites and the postoperative survival of the flap lobes in multiple wounds group were similar to those in single wound group (P>0.05). A total of 22 flap lobes were obtained in 10 surgeries and repaired 18 wounds in early group, and 24 flap lobes were obtained in 11 surgeries and repaired 19 wounds in late group. The incidence of postoperative hematoma, infection, vascular crisis, and survival of flap lobes in early group were similar to those in late group (P>0.05). There were no statistically significant differences in the patients' satisfaction degree with the therapeutic effect of each surgery at the last follow-up between early group and late group (t=0.701, P>0.05). At the last follow-up, the function evaluation score of 9 upper limbs in early group was 90 (85, 97) points, significantly higher than 80 (40, 85) points of 11 upper limbs in late group (Z=2.431, P<0.05). Conclusions: Free lobulated anterolateral thigh perforator flap is suitable for simultaneous repair of multiple electric burn wounds of limbs, as well as the repair of a single large irregular wound. It has the clinical advantages of less damage to the donor site and good repair quality. The early flap transplantation is beneficial to improve the function of limbs with electric burns.

[Transplantation of compound tissue flap of toe to reconstruct the thumb with necrosis caused by electric burns in four patients]

From January 2010 to December 2017, 4 patients of thumb with necrosis caused by electric burns (all male, aged from 31 to 58 years) were admitted to our hospital, with 1 patient of second degree injury of right thumb, 2 patients of third degree injury of right thumb, and 1 patient of third degree injury of left thumb. Routine debridement under general anesthesia was performed within 7 days after injury. The compound tissue flap of contralateral second toe was transplanted to reconstruct the thumb with third degree defect, and compound tissue flap of ipsilateral distal hallex was transplanted to reconstruct the thumb with second degree defect. Dorsalis pedics artery was anastomosed with radial artery, saphenous vein or dorsalis pedics vein was anastomosed with cephalic vein. The donor site was transplanted with split-thickness skin graft from autologous thigh. All the tissue flaps and skin grafts survived in 2 weeks after surgery. Within 1 year of follow-up, the reconstructed thumbs can achieve radial abduction and palmar abduction with good function. Reconstruction of thumb with free transplantation of compound tissue flap of toe is a good method to repair thumb with necrosis caused by electric burn.

[Clinical application of computed tomography angiography and three-dimensional reconstruction in repairing high-voltage electrical burn wounds in necks, shoulders, axillas, and upper arms with tissue flaps]

Objective: To explore the application value of computed tomography angiography (CTA) and three-dimensional reconstruction in repairing high-voltage electrical burn wounds in necks, shoulders, axillas, and upper arms with tissue flaps. Methods: From December 2014 to December 2018, 12 patients with high-voltage electrical burns in necks, shoulders, axillas, and upper arms were hospitalized. The size of wounds ranged from 13 cm×10 cm to 32 cm×15 cm after complete debridement. Before tissue flap repair, the subclavian artery-axillary artery-brachial artery and their branches were examined by CTA. The main target vessels and their branches were conducted by three-dimensional reconstruction, and the development of the axis vessels for the tissue flaps planning to dissect and their branches were observed. For wounds in upper arms, amputation stump bone exposed wounds, and wounds in axillas and the anterior, the latissimus dorsi myocutaneous flap is the first choice for repair, if the thoracodorsal artery and internal and external branches are well developed according to CTA examination. Latissimus dorsi myocutaneous flaps were used in 6 patients with the area of myocutaneous flap ranging from 16 cm×12 cm to 32 cm×17 cm. All the donor sites were covered by split-thickness skin graft of thighs. For large wounds in occiputs, necks, and scapulas, the contralateral lower trapezius myocutaneous flap is the first choice for repair, if the superficial descending branch and deep branch of the contralateral transverse cervical artery are well developed according to CTA examination. For small wounds in necks and scapulas, the ipsilateral lower trapezius myocutaneous flap can be used for repair, if the superficial descending branch of the ipsilateral transverse cervical artery is well developed according to CTA examination. Lower trapezius myocutaneous flaps were used in 4 patients with the area of myocutaneous flap ranging from 18 cm×12 cm to 25 cm×17 cm. The donor site of one patient was sutured directly and the donor site of the other 3 patients was covered by split-thickness skin graft of thighs. For wounds in the posteromedial side of upper arms and the anterior side of axillas, the lateral thoracic skin flaps can be used for repair, if the latissimus dorsi myocutaneous flap can not be utilized for reasons of back burn or no muscle is needed for dead space, when the blood supply of side chest skin is reliable according to CTA examination. Lateral thoracic skin flaps were used in 2 patients with the area of skin flap ranging from 16 cm×12 cm to 17 cm×14 cm. The donor site of one patient was sutured directly and the donor site of the other one patient was covered by split-thickness skin graft of thigh. Results: During the operation of tissue flap repair in 12 patients, the orientation and starting position of the axis vessels were consistent with those observed by CTA examination before operation. All the tissue flaps survived after operation. During follow-up of 1 to 24 months, the patients were satisfied with no serious scar contracture affecting the function nor secondary infection or chronic ulcer. Conclusions: CTA and its three-dimensional reconstruction technique can clearly reconstruct the subclavian artery-axillary artery-brachial artery and their branches before repair of high-voltage burn wounds in necks, shoulders, axillas, and upper arms. It can be used to observe whether the vessels are embolized or not and the starting position and orientation of blood vessels, which can provide an important reference for the selection of tissue flap transplantion.

[Effects of ultrathin abdomen flap on repairing deep electric burn wounds in finger of pediatric patients]

Objective: To investigate the effects of ultrathin abdomen flap in repairing deep electric burn wounds in finger of pediatric patients. Methods: A total of 14 pediatric patients with simple electric burns in finger were admitted to our unit from March 2013 to October 2017. Six patients had electric burns in one finger, 5 patients had electric burns in two fingers, and 3 patients had electric burns in three fingers. The size of wounds in single finger ranged from 2.0 cm×1.0 cm to 3.5 cm×2.0 cm. After complete preoperative examination, wounds debridement and ultrathin abdomen flap repair operation were performed on 3 to 6 days post injury. Six pediatric patients were treated with abdominal random flap, 4 patients were treated with inferior epigastric artery paraumbilical perforator bilobed flap, and the other 4 patients were treated with superficial circumflex iliac artery bilobed flap. The size of flaps ranged from 4.0 cm×2.0 cm to 8.0 cm×4.0 cm. The donor sites were sutured directly. Results: The flaps of 14 pediatric patients survived well after operation, and no flap showed blood supplying disorder. During follow-up of 3 to 24 months, the appearance and function of fingers were good, and the donor sites recovered well, with no cicatrix contracture deformity. Conclusions: The ultrathin abdomen flap is one of the good choices for repairing deep electric burn wounds in finger of pediatric patients.

[Effects of anteriolateral thigh perforator flap and fascia lata transplantation in combination with computed tomography angiography on repair of electrical burn wounds of head with skull exposure and necrosis]

Objective: To explore the effects of anteriolateral thigh perforator flap and fascia lata transplantation in combination with computed tomography angiography (CTA) on repair of electrical burn wounds of head with skull exposure and necrosis. Methods: Seven patients with head electrical burns accompanied by skull exposure and necrosis were admitted to our burn center from March 2016 to December 2017. Head CTA was performed before the operation. The diameters of the facial artery and vein or the superficial temporal artery and vein were measured, and their locations were marked on the body surface. Preoperative CTA for flap donor sites in lower extremities were also performed to track the descending branch of the lateral circumflex femoral artery with the similar diameter as the recipient vessels on the head, and their locations were marked on the body surface. Routine wound debridement and skull drilling were performed successively. The size of the wounds after debridement ranged from 12 cm×8 cm to 20 cm×12 cm, and the areas of skull exposure ranged from 8 cm×6 cm to 15 cm×10 cm. Anteriolateral thigh perforator flaps with areas from 13 cm×9 cm to 21 cm×13 cm containing 5-10 cm long vascular pedicles were designed and dissected accordingly. The fascia lata under the flap with area from 5 cm×2 cm to 10 cm×3 cm was dissected according to the length of vascular pedicle. The fascia lata was transplanted to cover the exposed skull, and the anteriolateral thigh perforator flap was transplanted afterwards. The descending branch of the lateral circumflex femoral artery and its accompanying vein of the flap were anastomosed with superficial temporal artery and vein or facial artery and vein before the suture of flap. The flap donor sites were covered by intermediate split-thickness skin graft collected from contralateral thigh or abdomen. Results: The descending branch of the lateral circumflex femoral artery and its accompanying vein were anastomosed with superficial temporal artery and vein in six patients, while those with facial artery and vein in one patient. All the flaps survived after the operation, and no vascular crisis was observed. Wound healing was satisfactory. One patient was lost to follow up. Six patients were followed up for 6 to 10 months. The patients were bald in the head operation area with acceptable appearance. No psychiatric symptom such as headache or epileptic seizure was reported. The flap donor sites were normal in appearance. The muscle strength of the lower extremities all reached grade V. The sensation and movement of the lower extremities were normal. Conclusions: Anterolateral thigh perforator flap with fascia lata transplantation can effectively repair electrical burn wounds of head with skull exposure and necrosis. The fascia lata can be used to protect the vascular pedicle of flaps, which is beneficial to the survival of the flap. Preoperative head and lower extremities CTA can provide reference for intraoperative vascular exploration in donor site and recipient area, so as to shorten operation time.

[Wound repair and functional reconstruction of high-voltage electrical burns]

In the repair of burn wound, high-voltage electrical burn wound is still the most complicated and the most difficult one to deal with. According to the clinical experience of author and the literature at home and abroad, this article systematically discusses the early treatment of high-voltage electrical burn wounds, including limbs escharotomy, fasciotomy, and early debridement, and the repair of high-voltage electrical burn wounds in various parts, especially in some special parts, focusing on the repair of the life-threatening parts and site of large vascular injury. At the same time, this article discusses the feasibility and necessity of functional reconstruction. We should make full use of modern repair technology and innovation, interdisciplinary cooperation, so as to reduce disability rate, amputation rate, and mortality of patients with high-voltage electrical burns as far as possible.

[Changes of platelet rheological behavior and the interventional effects of ulinastatin in rats with high-voltage electrical burns]

Objective: To explore the influence of high-voltage electrical burns on the number of platelet aggregation, β-thromboglobulin (β-TG) and platelet factor 4 (PF-4) and the interventional effects of ulinastatin in rats with high-voltage electrical burns. Methods: A total of 240 Sprague-Dawley rats were divided into sham injury (SI) group, simple electrical burn (SEB) group, normal saline (NS) group, and ulinastatin (UTI) group according to the random number table, with 60 rats in each group. The electrical current was applied to the outside proximal part of left forelimb of rats and exited from the outside proximal part of right hind limb of rats. Rats in groups SEB, NS, and UTI were inflicted with high-voltage electrical burn wounds of 1 cm×1 cm at current entrances and exits, with the voltage regulator and experimental transformer. Rats in group SI were sham injured through connecting the same equipments without electricity. At 2 min post injury, rats in group NS were intraperitoneally injected with 2 mL/kg NS, and rats in group UTI were intraperitoneally injected with 2×10(4) U/kg UTI of 10 g/L. At 15 min before injury and 5 min, 1 h, 2 h, 4 h, 8 h post injury, 10 rats in each group were selected to collect 5-7 mL blood of heart respectively. Blood of 0.05 mL were collected to make fresh blood smear for observing the number of platelet aggregation, and serum were separated from the remaining blood to determine content of β-TG and PF-4 with enzyme-linked immunosorbent assay. Data were processed with analysis of factorial design of variance, student-Newman-Keuls test, Kruskal-Wallis H test, Wilcoxon rank sum test, and Bonferroni correction. Results: (1) At 15 min before injury, the numbers of platelet aggregation of rats were close among groups SI, SEB, NS and UTI (5.9±1.2, 5.8±1.2, 5.9±1.3, 5.9±1.1, respectively, with P values above 0.05). At 5 min, 1 h, 2 h, 4 h, 8 h post injury, the numbers of platelet aggregation of rats in group SEB were 57.2±16.3, 59.1±16.9, 60.8±20.6, 83.6±24.9, and 83.4±30.3, respectively, obviously more than those in group SI (6.0±1.3, 6.0±1.4, 5.9±1.4, 5.7±1.1, and 5.8±1.3, respectively, with P values below 0.001); the numbers of platelet aggregation of rats in group UTI were 29.6±7.4, 31.9±10.1, 35.0±14.2, 43.0±13.6, and 35.2±11.1, respectively, obviously more than those in group NS (58.3±16.1, 63.9±18.0, 60.8±17.7, 74.2±23.0, and 82.3±21.9, respectively, with P values below 0.001). There was no significantly statistical difference in the number of platelet aggregation of rats in group SI between each two time points within the same group (with P values above 0.05), but the number of platelet aggregation of rats in the other 3 groups at each time point post injury was significantly more than that of the same group at 15 min before injury (with P values below 0.001). (2) At 2, 4, and 8 h post injury, β-TG content of serum of rats in group SEB was significantly higher than that in group SI (with Z values from -3.780 to -3.477, P values below 0.05). At 5 min and 4 h post injury, β-TG content of serum of rats in group UTI was significantly lower than that in group NS (with Z values respectively -3.477 and -3.780, P values below 0.05). There was no significantly statistical difference in β-TG content of serum of rats in group SI at all time points of the same group (χ(2)=0.130, P >0.05). At 2, 4, and 8 h post injury, β-TG content of serum of rats in group SEB was significantly higher than that of the same group at 15 min before injury (with Z values from -3.780 to -3.553, P values below 0.05). At 5 min, 1 h, and 4 h post injury, β-TG content of serum of rats in group NS was significantly higher than that of the same group at 15 min before injury (with Z values from -3.780 to -3.477, P values below 0.05). At 1 and 4 h post injury, β-TG content of serum of rats in group UTI was significantly higher than that of the same group at 15 min before injury (with Z values respectively -3.250 and -3.780, P values below 0.05). (3) At 2 and 8 h post injury, PF-4 content of serum of rats in group SEB was significantly higher than that in group SI (with P values below 0.05). At 2 h post injury, PF-4 content of serum of rats in group UTI was significantly higher than that in group NS (P<0.05), and at 4 and 8 h post injury, PF-4 content of serum of rats in group UTI was significantly lower than that in group NS (with P values below 0.05). At all time points, PF-4 content of serum of rats in group SI was close (with P values above 0.05). At 2 and 8 h post injury, PF-4 content of serum of rats in group SEB was significantly higher than that of the same group at 15 min before injury (with P values below 0.05). At 1, 4, and 8 h post injury, PF-4 content of serum of rats in group NS was significantly higher than that of the same group at 15 min before injury (with P values below 0.05). There were significantly statistical differences in PF-4 content of serum of rats between all time points except for 5 min post injury and 15 min before injury (with P values below 0.05). Conclusions: Increasing number of platelet aggregation and abnormal secretion of β-TG and PF-4 of rats with high-voltage electrical burns can lead to microcirculation disturbance. UTI can alleviate microcirculation disturbance caused by high-voltage electrical burns by reducing the number of platelet aggregation and inhibiting secretion of β-TG and PF-4.

[Epidemiological investigation on 2 133 hospitalized patients with electrical burns]

Objective: To analyze the epidemiological characteristics of the hospitalized patients with electrical burns in Institute of Burns of Tongren Hospital of Wuhan University & Wuhan Third Hospital (hereinafter referred to as Institute of Burns of Wuhan Third Hospital), so as to provide reference for the prevention and treatment of electrical burns. Methods: Medical records of all hospitalized burn patients in Institute of Burns of Wuhan Third Hospital from January 2004 to December 2016 were collected. Genders, ages, social categories, seasons of injury, total burn areas, depths of wounds, electrical voltages of injury, sites of wound, treatment methods, amputation rates, lengths of hospital stay, operation costs, hospitalization costs, and treatment outcomes of the electrical burn patients were collected. Treatment methods, lengths of hospital stay, operation costs, and hospitalization costs of the thermal burn patients were collected and compared with those of the electrical burn patients. Electrical voltages of injury, amputation rates, operation costs, hospitalization costs, and treatment outcomes were compared and analyzed between the electrical contact burn patients and the electrical arc burn patients. Data were processed with Chi-square test and Wilcoxon rank-sum test. Results: During the 13 years, 23 534 burn patients were admitted to Institute of Burns of Wuhan Third Hospital, among whom 2 133 (9.1%) were with electrical burns, without obvious variation in admission number of electrical burn patients every year. There were 1 418 patients (66.5%) with electrical contact burns and 715 patients (33.5%) with electrical arc burns. The ratio of male to female was 11.2∶1.0 among the electrical burn patients with known genders. The proportions of three age groups of more than 20 years old and less than or equal to 30 years old, more than 30 years old and less than or equal to 40 years old, and more than 40 years old and less than or equal to 50 years old were relatively higher, which were 18.3% (391/2 133), 22.1% (471/2 133), and 24.6% (525/2 133), respectively. The first three social category groups in proportions were workers, peasants, and preschool children, which were 57.9% (1 235/2 133), 14.6% (311/2 133), and 6.0% (128/2 133), respectively. Among the electrical burn patients with known seasons of injury, most cases were injured in summer (659 cases, accounting for 34.1%), obviously more than the proportions in autumn (537 cases, accounting for 27.8%), spring (455 cases, accounting for 23.5%), and winter (283 cases, accounting for 14.6%), with χ(2) values from 8.414 to 149.573, P values below 0.01. The group of patients with total burn areas less than 10% total body surface area (TBSA) occupied the highest proportion (1 603 cases, accounting for 75.15%), among whom 229 (10.74%) were with scattered small wounds which were less than 1% TBSA. The percentage of electrical contact burn patients with deep wounds was 79.1% (1 122/1 418), which was obviously higher than 2.5% (18/715) of the electrical arc burn patients (χ(2)=381.741, P<0.001). Among the patients with known electrical voltages of injury, patients injured by high voltage among the electrical contact burn patients accounted for 78.4% (469/598), which was obviously higher than 8.7% (11/127) of the electrical arc burn patients (χ(2)=227.893, P<0.001). The most common wound site of the electrical burn patients was upper limbs (1 650 cases, accounting for 63.2%), followed by lower limbs (382 cases, accounting for 14.6%), head and neck (292 cases, accounting for 11.2%), trunk (247 cases, accounting for 9.5%), and hip and perineum (40 cases, accounting for 1.5%). The operation rate of electrical burn patients was 32.4% (691/2 133), obviously higher than 19.1% (3 860/20 209)of the thermal burn patients during the same period (χ(2)=210.255, P<0.001). Wounds of 116 electrical contact burn patients were repaired with free flap by vascular anastomosis, of which 9 (7.8%) failed. The length of hospital stay, the operation cost, and the hospitalization cost of electrical burn patients were (28±29) d, (9 534±16 935) and (44 258±93 012) Yuan, respectively, obviously longer or higher than those of the thermal burn patients during the same period [(17±19) d, (2 990±8 916) and (23 291±88 340) Yuan, respectively, with Z values from -21.323 to -10.996, P values below 0.001]. The amputation rate and the death rate of electrical burn patients were 3.8% (82/2 133) and 0.8% (16/2 133) respectively. Compared with those of electrical arc burn patients, the amputation rate and the operation cost of electrical contact burn patients were obviously higher (χ(2)=36.970, Z=-11.351, P values below 0.001), and the length of hospital stay of electrical contact burn patients was obviously longer (Z=-5.181, P<0.001). There were no significant differences in hospitalization cost and treatment outcome between the electrical contact burn patients and the electrical arc burn patients (Z=-1.461, χ(2)=1.673, P values above 0.05). Conclusions: The number and the proportion of hospitalized electrical burn patients in Institute of Burns of Wuhan Third Hospital were relatively high, indicating a hard task of prevention for electrical burns in Wuhan area. Working-age workers and farmers, and preschool children were the key groups in prevention from electrical burns. The length of hospital stay, the operation cost, and the hospitalization cost of electrical burn patients were obviously higher than those of thermal burn patients. The amputation rate and the operation cost of electrical contact burn patients were obviously higher than those of electrical arc burn patients, but there were no obvious differences in hospitalization cost or treatment outcome between them. Actively using tissue flaps including free flap to repair of wounds may be helpful to reduce the amputation rate, improve the results, and shorten the time of treatment.

[Wound repair and functional reconstruction of high-voltage electrical burns in wrists]

Objective: To explore the methods and effects of wound repair and functional reconstruction of high-voltage electrical burns in wrists. Methods: From January 2009 to June 2016, 71 patients with high-voltage electrical burns in wrists were hospitalized, with 118 wrist wounds including 21 of type Ⅰ, 69 of type Ⅱ, 9 of type Ⅲ, and 19 of type Ⅳ. According to the wrist injuries, different surgical operations were performed. Forearm amputation was conducted in 20 wrists with necrosis in the distal end. On the basis of fasciotomy for decompression, early debridement was performed on the other 98 wrist wounds. After debridement, wounds with area ranging from 10 cm×7 cm to 30 cm×18 cm were repaired with tissue flaps with abundant blood supply. Thirty-two wounds were repaired with pedicled groin flaps, 11 wounds with pedicled paraumbilical flaps, 3 wounds with pedicled anterolateral thigh island flaps, 9 wounds with combined abdominal axial pattern flaps, 37 wounds with free skin flaps or myocutaneous flaps, and 6 wounds with flow-through descending branch of lateral femoral circumflex artery flaps, with tissue flap area ranging from 12 cm×8 cm to 34 cm×20 cm. Ulnar artery or radial artery vascular reconstruction was performed in 20 wrist wounds. Forty-one donor sites were sutured directly, while 14 were closed by thin split-thickness skin grafts from same-side thighs, and 43 were closed by thin split-thickness skin grafts from opposite-side thighs. Fifty-three wrist wounds were performed with tendon and nerve repair surgery, of which 20 were performed with simple tendon and nerve release surgery. Flexor digitorum profundus tendons and (or) flexor pollicis longus tendons were reconstructed with autologous or allogeneic tendon transplantation in 33 wrist wounds, and the median nerve was repaired with sural nerve graft in 21 wrist wounds. In 6 to 24 months after the last operation, tendon function of 53 wrist wounds which had tendon repair was evaluated with finger total active motion (TAM) method, while median nerve function of 21 wrist wounds which had median nerve repair was evaluated with integrate estimation method. Results: (1) After forearm amputation, the incisions of 20 wrists with necrosis in the distal end were healed. (2) Among the 98 tissue flaps, 90 had good blood flow, while 8 had distal necrosis, of which 6 were healed after necrotic tissue removal and skin grafting, and two were sutured directly after debridement. Infection occurred under 7 flaps, of which 3 were healed by dressing change, and 4 were healed after second debridement. Twenty wrist wounds which had radial artery or ulnar artery repair had good blood supply of hand and amputation was avoided. During follow-up of 1 to 3 years, the incisions and flaps of patients who had tissue flap repair surgery healed well. (3) The excellent and good rate of TAM in each finger of the corresponding affected limbs of 53 wrist wounds which had tendon and nerve repair surgery was 51%. (4) Twenty wrists which had simple tendon and nerve release surgery were followed up for 1 to 2 years. The strength of muscle dominated by the median nerve was restored to grade Ⅴ in 1 wrist, grade Ⅳ in 3 wrists, and grade Ⅲ in 2 wrists. The strength of muscle dominated by the ulnar nerve was restored to grade Ⅳ in 3 wrists, with no recovery in other wrists. Sensory function examination showed grade S0 in 4 wrists, grade S1 in 2 wrists, grade S2 in 3 wrists, grade S3 in 8 wrists, and grade S4 in 3 wrists. Twenty-one wrists which had median nerve repair were followed up for 1 to 2 years. There was no recovery in muscle strength dominated by the median nerve. Sensory function examination showed grade S0 in 3 wrists, grade S1 in 5 wrists, grade S2 in 8 wrists, and grade S3 in 5 wrists. Conclusions: It is a good method to sequentially conduct early fasciotomy for decompression, early debridement, vascular reconstruction, transplant of tissue flap with abundant blood supply, tendon and nerve repair in repairing electrical burn wounds of wrists, avoiding amputation, and reconstructing hand function according to the condition of electrical burns of wrists.

[Clinical research of features of magnetic resonance imaging of high-voltage electrical burns in limbs at early stage]

Objective: To analyze the features of magnetic resonance imaging (MRI) of patients with high-voltage electrical burns in limbs at early stage. Methods: Thirty-eight patients with high-voltage electrical burns, conforming to the study criteria, were hospitalized in our unit from March 2013 to August 2016. T(1) weighted imaging (T(1)WI), T(2)WI, fat-suppression T(2)WI plain scan, and fat-suppression T(1)WI enhanced scan of MRI were performed in 78 limbs, including 56 upper limbs and 22 lower limbs at post injury hour 72. The MRI signal characteristics of electrical burns in skin and subcutaneous tissue, skeletal muscle, tendon, joint ligament, and skeleton of limbs were analyzed. " Sandwich-like" necrosis and injury in skeletal muscle, injuries of tendon, joint ligament, and skeleton were observed. MRI signal characteristics of amputated upper limbs and salvaged limbs were also analyzed. All patients underwent surgery within 24 h after MRI examination, and the muscle vitality was judged during operation. Muscle tissue without reaction to electrical stimulation which was completely necrotic as shown by MRI, muscle tissue with weak reaction to electrical stimulation which was injured with blood supply as shown by MRI, and muscle tissue with edema as shown by MRI were collected, and then the pathological characteristics of muscle tissue were observed with HE staining. Results: (1) The defect area of patients at entrance of current was bigger than that at exit. The skin and subcutaneous tissue extensively unevenly thickened. T(2)WI manifested hyperintensity, and T(1)WI manifested isointensity, while fat-suppression enhanced T(1)WI manifested uneven enhancement. Zonal effusion was seen in the region of serious subcutaneous edema. (2) For complete necrosis of skeletal muscle, T(2)WI manifested hypointense, isointensity, or slight hyperintensity, and T(1)WI manifested isointensity, slight hyperintensity, or mixed signal of isointensity and slight hyperintensity, while fat-suppression enhanced T(1)WI manifested most no enhancement area with clear boundary. The MRI signals of injured skeletal muscle could be divided into two types. Type Ⅰ signal was for partial necrotic muscle adjacent to the completely necrotic zone. T(2)WI manifested uneven hyperintensity or slight hyperintensity, with unclear boundary. T(1)WI manifested isointensity or slight hyperintensity. Fat-suppression enhanced T(1)WI manifested significant banding or laciness enhancement. Type Ⅱ signal was for deep muscle tissue far from the complete necrotic zone. T(2)WI manifested hyperintensity, and T(1)WI manifested isointensity or main isointensity mixed with hyperintensity, while fat-suppression enhanced T(1)WI manifested uneven moderate or slight enhancement. Normal muscle signal, type Ⅰ signal, and type Ⅱ signal were all mixed with necrotic signal, showing " sandwich-like" change. For skeletal muscle edema, T(2)WI manifested slight hyperintensity and unclear boundary, and T(1)WI manifested hypointense, while fat-suppression enhanced T(1)WI manifested no obvious enhancement. (3) For complete necrosis of tendon, T(2)WI manifested isointensity or slight hyperintensity, and T(1)WI manifested isointensity, while fat-suppression enhanced T(1)WI manifested no enhancement. For tendon injury, T(2)WI manifested isointensity, and T(1)WI manifested isointensity or hypointense, while fat-suppression enhanced T(1)WI manifested slight enhancement. (4) Severe injury of wrist joint were manifested as complete necrosis of soft tissue around joint. T(2)WI manifested slight hyperintensity or isointensity, and T(1)WI manifested isointensity, while fat-suppression enhanced T(1)WI manifested no enhancement or slightly uneven enhancement. For completely destroyed wrist joints, the structures were not clear from outside to inside. T(2)WI manifested slight hyperintensity or isointensity, and T(1)WI manifested hypointense or isointensity, while fat-suppression enhanced T(1)WI manifested no enhancement. For elbow injury, T(2)WI manifested hyperintensity, and T(1)WI manifested isointensity or hypointense, while fat-suppression enhanced T(1)WI manifested uneven enhancement. For knee injury, T(2)WI manifested hyperintensity, and T(1)WI manifested hypointense, while fat-suppression enhanced T(1)WI manifested slight enhancement. (5) For bone edema, T(2)WI manifested isointensity, while fat-suppression T(2)WI manifested slight hyperintensity. T(1)WI manifested isointensity, and fat-suppression enhanced T(1)WI manifested patchy enhancement. (6) MRI of amputated upper limbs showed necrosis signals, type Ⅰ signals, type Ⅱ signals, and mixed signals of type Ⅰ and type Ⅱ in skeletal muscle. The necrosis signal and type Ⅰ signal area of the distal end were more than 50% greater than those of the lesion. The scope of the ecological tissue was large and the boundary was not clear. There were diffuse injuries in both anterior and posterior muscles, and the ulnar and radial artery pulsation disappeared in the upper limbs. The MRI of salvaged limbs were type Ⅰ signal, type Ⅱ signal, mixed signals of type Ⅰ and type Ⅱ, and local necrosis signals of skeletal muscle. The type Ⅰ signal was the main type, and the distal end showed type Ⅱ signal. (7) For completely necrotic skeletal muscle as shown by MRI, surgical exploration showed loss of muscle viability, and pathological examination showed complete necrosis of striated muscle tissue. For injury area of skeletal muscle as shown by MRI, surgical exploration showed interecological muscle with activity worse than mormal muscle, and pathological examination showed normal muscle cells and muscle fiber mixed with necrotic striated muscle cells having karyopyknosis, with different degree of injury. For edema area of skeletal muscle as shown by MRI, surgical exploration showed swelling skeletal muscle and normal muscle vitality, and pathological examination showed striated muscle interstitial edema with a large number of inflammatory cells infiltration. The manifestions of MRI were consistent with the results of surgical exploration and pathological examination. Conclusions: Skeletal muscle complete necrosis, injury, and edema could be preferably differentiated by MRI, and the definite scope and depth of electrical injury, the injury of skin, tendon, joint ligament, and bone could also be displayed well on MRI. It can provide objective imaging basis for the diagnosis of high-voltage electrical burns in limbs at early stage, the establishment of clinical operation plan, and the judgment of intraoperative tissue vitality.

[Prevention and treatment of electrical burn injury: much progresses achieved yet further efforts still needed]

Electrical burn injury is very common, including electrical contact burn, electrical arc burn, and lightning burn, etc. Electrical burn patients account for 0.04 to 5 percent of all burn victims in the developed countries, while it hit up to 27 percent in the developing countries, much more than the global average of 4.5 percent. Historical and recent data have shown that the electrical burn injuries in China, either for the case number, the proportion of burn patients in hospital, or the population incidence per year, are much higher than those of the developed countries and the global average. Before the 1960s, conservative treatment or skin grafts after repeated debridements were used for electrical burns, resulting in high rates of amputation and severe deformity. In the 1960s, transplantation of flaps after debridement in early stage were used for repairing wrist electrical burn wounds, breaking through the traditional conservative methods. In the 1980s, local, distant and island pedicled skin or myocutaneous flaps were widely used for early stage repair of electrical burn wounds. In recent years, along with the increasing experience of evaluating the blood vessel injuries and the development of microsurgical techniques, free flaps have been more and more used to cover the deep wounds of electrical burns in early stage, leading to much better effects and shorter length of hospital stay. With the persistent efforts of the burn specialists in the last decades, great improvements have been made for the treatment of electrical burn injuries in China. Future study on decoding the full mechanism of electrical burn injury, exploring new methods to save the injured but not yet necrotic tissue, are still needed to improve the treatment and reduce amputation and deformity of electrical burn injury.

[Effects of flap or myocutaneous flap combined with fascia lata or composite mesh on repairing severe high-voltage electrical burn wounds in abdomen of patients]

Objective: To investigate the effects of flap or myocutaneous flap combined with fascia lata or composite mesh on repairing wounds in abdomen of patients with severe high-voltage electrical burn. Methods: From January 2010 to May 2017, 11 patients with severe high-voltage electrical burn in abdomen were hospitalized in our burn wards. In 3 hours to 7 days after burn, operation was performed when patients were in stable condition. After debridement, intestines with necrosis or perforation in 4 patients with peritoneal defects were resected and intestinal anastomosis was performed. The size of abdominal wounds after debridement ranged from 13 cm×9 cm to 41 cm×32 cm. Five patients were treated with rectus abdominis myocutaneous flap and size of which ranged from 14 cm×10 cm to 30 cm×17 cm. Among the above 5 patients, 4 patients with peritoneal defects used composite mesh of 25 cm×20 cm to enhance abdominal wall. Three patients were treated with tensor fascia lata myocutaneous flap, and size of the flap ranged from 24 cm×10 cm to 27 cm×13 cm. Three patients were treated with anterolateral thigh flap with fascia lata, and one of them was treated with the lobulated flap; size of the flap ranged from 18 cm×13 cm to 25 cm×15 cm. The later 6 patients used fascia lata of flap to enhance abdominal wall. The donor sites were sutured directly or repaired with intermediate split-thickness skin graft of thigh. Results: After operation, flaps or myocutaneous flaps of patients were survived, and strength of abdominal wall recovered. During follow-up of 6 month to 1 year, flaps or myocutaneous flaps were in good appearance, with no ankylenteron or abdominal wall hernia. Conclusions: Flap or myocutaneous flap combined with fascia lata or composite mesh can achieve good effects on repairing severe high-voltage electrical burn wounds in abdomen.

[Clinical effects of repair of wounds in fingers after electrical burn with wrist perforator free flaps]

Objective: To explore the clinical effects of repair of wounds in the fingers after electrical burn with wrist perforator free flaps. Methods: Twelve patients (13 fingers) with electrical burn were hospitalized in our burn ward from January 2016 to January 2017. After radical debridement, the size of wounds ranged from 5.0 cm×2.0 cm to 10.0 cm×7.0 cm. Wounds with size below or equal to 6.0 cm ×2.5 cm were repaired with free flaps based on the superficial palmar branch of radial artery, with flap area ranging from 2.5 cm×2.2 cm to 6.0 cm×4.5 cm. The superficial palmar branch of radial artery, subcutaneous vein, and palmar cutaneous branch of the median nerve underwent end-to-end anastomosis with digital proper artery, dorsal superficial vein, and digital proper nerve in the finger, respectively. The donor sites were sutured directly. Wounds with size larger than 6.0 cm×2.5 cm were repaired with free flaps based on the dorsal carpal branch of ulnar artery, with flap area ranging from 4.5 cm×3.0 cm to 12.0 cm×8.5 cm. The dorsal carpal branch of ulnar artery, subcutaneous vein, and medial antebrachial cutaneous nerve underwent end-to-end anastomosis with digital proper artery, dorsal superficial vein, and digital proper nerve in the finger, respectively. The donor sites were sutured directly or covered by full-thickness skin graft from abdomen. Results: Five free flaps based on the superficial palmar branch of radial artery and 8 free flaps based on the dorsal carpal branch of ulnar artery were used in the patients. In one week after surgery, 12 flaps survived completely, while one free flap based on the dorsal carpal branch of ulnar artery suffered from slight infection, after depressing change, it survived in the end. After the follow-up of half a year, the flaps were full in shape and the distance of two-point discrimination of ranged from 4.0 to 7.0 mm. The fingers showed good functional recovery and no deformity. The grade of function of the fingers was excellent in 10 cases and good in 3 cases. There were small incision scars in donor sites. Conclusions: The wrist perforator free flap is safe and reliable for repairing electrical burn wound of finger. The wounded finger shows good appearance and function after operation.

[Effects of flow-through descending branch of lateral circumflex femoral artery flap on repairing high-voltage electrical burn wounds of wrist of patients]

Objective: To investigate the effects of flow-through descending branch of lateral circumflex femoral artery flap on repairing high-voltage electrical burn wounds of wrist of patients. Methods: From January 2014 to June 2016, 5 patients with high-voltage electrical burn of unilateral wrist were hospitalized in our burn ward, with extensive necrosis of skin soft tissue of burn wrist. Five patients were transferred to our burn ward 6 to 12 days post injury after undergoing emergency dermotomy of wrist to reduce tension in other hospitals. In 2 to 3 days after admission, operation was performed by two surgeon group at the same time, when patients' general condition were stable. One group underwent debridement and the other group designed and dissected flap according to the range of skin soft tissue defect of wrist. Wrist wounds after debridement ranged from 15 cm×10 cm to 24 cm×15 cm. Three patients were treated with flow-through descending branch of lateral circumflex femoral artery flap and great saphenous vein for repairing wounds of wrist and reconstruction of ulnar and radial artery. Two patients were treated with flow-through descending branch of lateral circumflex femoral artery flap for repairing wounds of wrist and reconstruction of ulnar artery. The dissected flaps ranged from 16 cm×12 cm to 26 cm×16 cm and the length of bridging vessel ranged from 15 to 21 cm. Results: The flow-through descending branch of lateral circumflex femoral artery flaps of five patients survived well. Wounds of 4 patients healed and wounds of 1 patient with infection under the flap on 3 days after operation healed after changing wound dressing and undergoing debridement for 2 weeks. After the operation, wrists and hands of 5 patients had adequate blood supply and ulnar and radial artery recovered patency. Follow-up of patients for 6 months to 1 year showed good flap appearance and adequate blood supply of burn hands. Conclusions: The flow-through descending branch of lateral circumflex femoral artery flap can repair wrist wounds and recover blood supply of hands and it is a good method for repairing high-voltage electrical burns of wrist.

[Influences of high-voltage electrical burns on microcirculation perfusion on serosal surface of small intestine of rats and the interventional effects of pentoxifylline]

Objective: To investigate influences of high-voltage electrical burns on microcirculation perfusion on serosal surface of small intestine of rats and the interventional effects of pentoxifylline (PTX). Methods: Totally 180 SD rats were divided into sham injury group, simple electrical burn group, and treatment group according to the random number table, with 60 rats in each group. The electrical current was applied to the outside proximal part of left forelimb of rats and exited from the outside proximal part of right hind limb of rats. Rats in simple electrical burn group and treatment group were inflicted with high-voltage electrical burn wounds of 1cm×1cm at current entrances and exits, with the voltage regulator and experimental transformer. Rats in sham injury group were sham injured through connecting the same equipments without electricity. At 2 min post injury, rats in sham injury group and simple electrical burn group were intraperitoneally injected with 2 mL normal saline, and rats in treatment group were injected with 2 mL PTX injection (50 mg/mL). At 15 min before injury and 5 min, 1 h, 2 h, 4 h, and 8 h post injury, 10 rats in each group were selected to collect blood of heart respectively. Serum were separated from the blood to determine the level of soluble vascular cell adhesion molecule-1(sVCAM-1) with enzyme-linked immunosorbent assay method. The number of adhesional leukocyte in mesenteric venule of rats was determined with Bradford variable projection microscope system. The microcirculation perfusion on serosal surface of small intestine of rats was detected with laser Doppler perfusion imager. Data were processed with analysis of variance of factorial design and LSD test. Results: (1) At 5 min, 1 h, 2 h, 4 h, 8 h post injury, the serum content of sVCAM-1 in rats of simple electrical burn group were (8 502±1 158), (11 793±3 310), (9 960±2 146), (9 708±1 429), (7 292±1 386) ng/mL respectively, higher than that in sham injury group and treatment group [ (1 897±946), (1 882±940), (1 882±938), (1 888±946), (1 884±942) ng/mL, and (6 840±1 558), (6 742±2 465), (5 625±2 593), (2 373±1 463), (5 187±2 797) ng/mL, respectively, with P values below 0.001]. The serum content of sVCAM-1 in rats of sham injury group and treatment group at all time points post injury, except 4 h post injury of treatment group, was higher than that of the same group at 15 min before injury (with P values below 0.001). (2) At all time points post injury, the number of adhesional leukocyte in mesenteric venule of rats in simple electrical burn group was higher than that in sham injury group and treatment group (with P values below 0.001). The number of adhesional leukocyte in mesenteric venule of rats in simple electrical burn group and treatment group at all time points post injury was higher than that of the same group at 15 min before injury (with P values below 0.001). (3) At all time points post injury, the microcirculation perfusion on serosal surface of small intestine of rats in simple electrical burn group was lower than that in sham injury group and treatment group (with P values below 0.001). The microcirculation perfusion on serosal surface of small intestine of rats in simple electrical burn group and treatment group at all time points post injury was lower than that of the same group at 15 min before injury (with P values below 0.001). Conclusions: High-voltage electrical burns can increase the serum content of sVCAM-1, the number of adhesional leukocyte in mesenteric venule, and reduce microcirculation perfusion on serosal surface of small intestine of rats. PTX can inhibit secretion of serum sVCAM-1, reduce the number of adhensional leukocyte in mesenteric venule to alleviate microcirculation disturbance caused by high-voltage electrical burns.

[Analysis of microRNA expression profile in serum of patients with electrical burn or thermal burn]

Objective: To explore the differential expression of microRNAs in the serum among patients with electrical burn or thermal burn and healthy persons and to explore the significance. Methods: In this study we included three patients with electrical burn and three patients with thermal burn, conforming to the inclusion criteria and hospitalized in our burn ward from June to August 2015, and three healthy adult volunteers. Their serum samples were separated from whole blood and divided into electrical burn group, thermal burn group, and normal control group. Total RNA was extracted from their serum samples using Trizol method. The differentially expressed microRNAs (with differential ratio larger than or equal to 2.000, less than or equal to 0.500) among the three groups were screened by microRNA chip technique. Then cluster and Venn diagram analysis of the differentially expressed microRNAs were performed. Enrichment analysis of Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway was performed on the distinctly changed microRNAs (with differential ratio larger than or equal to 5.000, less than or equal to 0.500). Results: There were 220 differentially expressed microRNAs among serum of the three groups. MicroRNA expression profiles in serum of electrical burn and thermal burn groups were different from that in serum of normal control group. Compared with those in serum of normal control group, the expressions of 59 microRNAs changed more than 2.000 times in serum of electrical burn group, with 50 up-regulated microRNAs and 9 down-regulated microRNAs; the expressions of 40 microRNAs changed more than 2.000 times in serum of thermal burn group, with 21 up-regulated microRNAs and 19 down-regulated microRNAs. Compared with those in serum of thermal burn group, the expressions of 167 microRNAs changed more than 2.000 times in serum of electrical burn group. There were 17 exclusively expressed microRNAs in serum of thermal burn group and 26 exclusively expressed microRNAs in serum of electrical burn group, compared with those in serum of normal control group. Enrichment analysis of KEGG signaling pathway showed that compared with those in serum of normal control group, microRNAs which changed distinctly in serum of electrical burn group took part in the insulin secretion signaling pathway, arrhythmogenic right ventricular cardiomyopathy signaling pathway, hypertrophic cardiomyopathy signaling pathway, glutamatergic synapse signaling pathway, calcium signaling pathway, cyclic adenosine monophosphate signaling pathway, glycerophospholipid metabolism, pyrimidine metabolism, serotonergic synapse signaling pathway, etc, while microRNAs which changed distinctly in serum of thermal burn group took part in the tumor transcription misregulation signaling pathway, proteoglycans in tumor signaling pathway, microRNAs in tumor signaling pathway, long-term potentiation signaling pathway, citrate cycle signaling pathway, tumor necrosis factor signaling pathway, focal adhesion signaling pathway, endocytosis signaling pathway, insulin secretion signaling pathway, p53 signaling pathway, and estrogen signaling pathway, etc. Conclusions: MicroRNA expression profiles in serum of electrical and thermal burn are different from that in serum of healthy adult. The signaling pathways enriched with target genes which are regulated by the differentially expressed microRNAs are related to the pathological changes and clinical manifestations after electrical or thermal burn.