Free Muscle Transplantation Research Articles

Gracilis Flap Restoring Quality of Life in a Patient with Non Functional Anal Sphincter

An excellent technique for reconstructing the perineum following extensive perineal resection for restoration of a traumatised anal sphincter is the Gracilis myocutaneous flap. Direct anal trauma or pelvic injuries can separate the anal sphincters. An overlapping sphincteroplasty has a fair possibility of regaining acceptable fecal continence if roughly half of the sphincter ring is still functional. A case of a 22-year-old male who underwent Gracilis myocutaneous flap reconstruction after being diagnosed with a non functioning anal sphincter is reported. A free muscle transplant was done to repair the sphincter, utilising denervated muscle with an intact blood supply. New muscle was attached to those sphincter muscles which were still functional. The transplanted muscle receives new muscular fibers, enabling the repaired sphincter to contract voluntarily in addition to reflexively. The surgical approach is determined based on the presented sphincter defect. Free muscle transplantation can be preferred in cases where the external sphincter has some degree of functionality.

Transposition of functioning muscles in complex treatment of adult patients with injuries of the bracheric plexus (literature review)

Introduction. Injuries to the brachial plexus are one of the most severe types of injuries to the nerves of the upper limb, and variants with the separation of the roots from the spinal cord represent a very difficult category of injuries to treat. Among patients who have received such injuries, there is a very high incidence of disability, since it is possible to achieve only partial restoration of the function of the upper limb. Recently, the method of transposition of functioning muscles has been growing in popularity due to its reliability and relatively short recovery time of function.The purpose of the work is to analyze the literature data on the possibility of using the method of transposition of functioning muscles in the complex treatment of victims with brachial plexus injuries.The authors have searched PubMed and RSCI databases over the past 25 years for keywords: peripheral nerve damage, tendon transposition, transposition of functioning muscles, nerve injury, brachial plexus injury, spinal cord root avulsion. In the selected 23 most relevant papers, the muscles used for transposition, indications and timing of operations, results and complications were analyzed, compared with other methods of surgical treatment of brachial plexus injuries. The analysis of studies has shown that the transposition of functioning muscles allows in most cases to restore the target movement to the useful level of M3–M4 on the MRC scale, is a more reliable method and allows achieving better results, especially in patients with severe complete injuries of the brachial plexus. An important disadvantage of free hip thin muscle transplantation operations is the risk of microanastomosis thrombosis, which requires detailed preoperative planning and good microsurgical technique of the operating team.Conclusion. Free transplantation of 2 functioning muscles is currently the method of choice for restoring upper limb movements in patients with complete brachial plexus injuries.

Resolving Co-Contraction of the Elbow in Patient with Sequelae of Obstetric Brachial Plexus Palsy: A Cohort Study.

Obstetric brachial plexus palsy can cause deformities of the upper extremity in up to 92% of patients. Elbow reconstruction is difficult because co-contraction of the elbow flexor (EF) and elbow extensor (EE) muscles makes the traditional treatment strategy ineffective. The authors propose a novel strategy to minimize the effect of co-contraction, comprising transfer of an EF to the triceps and a staged gracilis muscle transplantation [functioning free muscle transplantation (FFMT)] to augment EF. The authors hypothesize this will lead to improved elbow flexion and extension, as well as decreased elbow flexion contracture. A single-center retrospective review of patients who received a gracilis FFMT for EF after EF-to-EE transfer was performed. EF/EE strength and range of motion data were collected from the last clinical visit. Patients were excluded if they had fewer than 1.5 years of follow-up. A control group with sequelae of obstetric brachial plexus palsy and nonsurgical treatment was used for comparison. Twenty-one patients were included. Average age at muscle transfer was 7.6 ± 5.5 years (range, 3 to 22 years) and at gracilis FFMT was 10.4 ± 6.0 years (range, 5 to 26 years). Average follow-up was 7.3 ± 6.5 years (range, 1.5 to 14.8 years). After EF-to-EE transfer, EE strength increased significantly from Medical Research Council grade 2.2 ± 0.4 to 3.4 ± 0.5 ( P < 0.0001) and EF decreased from 3.2 ± 1.1 to 1.1 ± 1.1 ( P < 0.0001) and recovered to grade 3.3 ± 0.7 after gracilis FFMT. EF contracture was significantly lower compared with that in the nonsurgical cohort ( P = 0.029). Patients who undergo EF-to-EE transfer followed by gracilis FFMT have equivalent EF strength with significantly improved EE and improved elbow flexion contracture. Therapeutic, IV.

Outcomes of Functioning Free Gracilis Muscle Transplantation to Restore Elbow Flexion in Late Brachial Plexus Birth Injury.

Restoring elbow function is challenging after late presenting brachial plexus birth injury (BPBI). Free functioning muscle transplantation (FFMT) using the gracilis muscle is a reliable procedure to restore elbow flexion in patients with impaired function after spontaneous recovery or failed surgical reconstruction. A retrospective review was performed on BPBI patients more than 2 years of age who received a FFMT between January 1993 and January 2018, with the aim of improving elbow flexion as the primary or secondary functional goal. Patients with preoperative elbow flexion Medical Research Council (MRC) grades less than 3 with more than or equal to 18 months of follow-up duration were included in the analysis. Patient demographic information and pre/postoperative clinical parameters including elbow flexion MRC scale, passive elbow range of motion, and complications were recorded. Surgical data including donor nerve choice, site of the FFMT tendon attachment, and necessity of concomitant procedures or reoperation were also analyzed. Fifty-six FFMTs were performed for the primary (29 patients) or secondary (26 patients) objective of restoring elbow flexion. The mean age at the time of the procedure was 9.6 years (standard deviation [SD] = 6.29, R = 3-35). Mean follow-up was 7.9 years (SD = 5.2). Elbow flexion improved from a median MRC grade 2 to 4 after a FFMT (p < 0.05). Patients who had a FFMT to restore two functions had 86% lower elbow flexion MRC grades than those who had a FFMT to restore flexion only (p < 0.05). Patients less than 12 years old at the time of surgery had more complications, reoperations, and rates of a flexion contracture more than or equal to 30 degrees than those aged more than 12 years (p < 0.05). FFMT is a reliable option for upper extremity reanimation. Patients aged less than 12 years old at the time of FFMT had significantly more complications, reoperations, and rates of postoperative elbow flexion contracture more than or equal to 30 degrees, but equivalent elbow flexion MRC grades. III.

Surgical Treatment for Postparalytic Facial Synkinesis: A 35-Year Experience.

Surgical intervention with combined myectomy and neurectomy followed by functioning free muscle transplantation has been proposed to effectively resolve the problem of postparalytic facial synkinesis since 1985, and it continues to be the authors' standard of care. The authors aim to provide evidence that this surgical strategy is effective for treatment of synkinesis and smile quality. One hundred three patients with postparalytic facial synkinesis were investigated (1985 to 2020). They all underwent extensive removal of the synkinetic muscles and triggered facial nerve branches in the cheek, nose, and neck regions, followed by gracilis functioning free muscle transplantation for facial reanimation. Ninety-four patients (50 with type II and 44 with type III postparalytic facial synkinesis), all of whom had at least 1 year of postoperative follow-up, were included in the study. Patient demographics and functional and aesthetic evaluations before and after surgery were collected. In the yearly distribution of the facial paralysis reconstruction, the incidence of surgical intervention increased from 15 percent before 2012 up to 24 percent in the years after. Young adults (79 percent) and female patients (63 percent) were the dominant population. Results showed a significant improvement of the facial smile quality, with more teeth visible while smiling, and a long-lasting decrease of facial synkinesis. Ninety-six percent of patients did not require botulinum toxin type A injection after surgery. Revision surgery for secondary deformity was 53 percent. Combined myectomy and neurectomy followed by functioning free muscle transplantation for type II and III synkinetic patients leads to promising and long-lasting results despite high revision rates. Refined techniques to decrease the revision rates are needed in the future. Therapeutic, IV.

Single Gracilis Functioning Free Muscle Transplantation for Simultaneous and Combined Reconstruction of Smile and Lagophthalmos in Complete Facial Paralysis

Single Gracilis Functioning Free Muscle Transplantation for Simultaneous and Combined Reconstruction of Smile and Lagophthalmos in Complete Facial Paralysis

ИСПОЛЬЗОВАНИЕ ЛОСКУТА ШИРОЧАЙШЕЙ МЫШЦЫ СПИНЫ ПРИ ПОСТТРАВМАТИЧЕСКОЙ ФУНКЦИОНАЛЬНОЙ НЕСОСТОЯТЕЛЬНОСТИ ВЕРХНЕЙ КОНЕЧНОСТИ

Objective: To improve the outcomes of surgical correction of upper limb dysfunction (ULD) using the latissimus dorsi flap (LDF). Methods: ULD occurred in 76 patients with Volkmann's ischemic contracture (VIC), post-traumatic soft tissue defects, and brachial plexitis in 57, 11, and 8 cases, respectively. Out of 57 patients with VIC, in 30 cases, a skin defect was observed along with severe degenerative changes in soft tissues, neurovascular bundles (NVBs) and tendons. Post-traumatic forearm defects (n=11) in 5 cases were accompanied by damage to the NVBs and tendons. In brachial plexitis, isolated injury to the musculocutaneous nerve occurred in 6 patients, and a combination of nerve lesions with radial nerve palsy – in 2 patients. Results: Transposition of LDF to the biceps brachii for the treatment of brachial plexitis, free muscle transplantation for the treatment of VIC and forearm soft tissue defects were performed in 8, 57, and 11 cases, respectively. Active forearm flexion after the muscle flap transposition was noted after 4 weeks. In contrast, after graft transplantation in VIC, the grip function restoration began after 6 months and improved within 1 year and beyond. Conclusion: Using the LDF in surgical correction of post-traumatic ULD allowed restoring the lost functions of the crushing grip and forearm flexion. For the forearm, only free flap transplantation with a relatively long period of limb function recovery is possible. In contrast, the traspositioned LDF to the biceps allows achieving the desired functional outcomes in the shortest possible time. Keywords: Upper limb, latissimus dorsi flap, Volkmann's contracture, soft-tissue defect, brachial plexitis.

Microanatomy of the Frontal Branch of the Facial Nerve: The Role of Nerve Caliber and Axonal Capacity.

A commonly seen issue in facial palsy patients is brow ptosis caused by paralysis of the frontalis muscle powered by the frontal branch of the facial nerve. Predominantly, static methods are used for correction. Functional restoration concepts include the transfer of the deep temporal branch of the trigeminal nerve and cross-facial nerve grafts. Both techniques can neurotize the original mimic muscles in early cases or power muscle transplants in late cases. Because axonal capacity is particularly important in cross-facial nerve graft procedures, the authors investigated the microanatomical features of the frontal branch to provide the basis for its potential use and to ease intraoperative donor nerve selection. Nerve biopsy specimens from 106 fresh-frozen cadaver facial halves were obtained. Histologic processing and digitalization were followed by nerve morphometric analysis and semiautomated axon quantification. The frontal branch showed a median of three fascicles (n = 100; range, one to nine fascicles). A mean axonal capacity of 1191 ± 668 axons (range, 186 to 3539 axons; n = 88) and an average cross-sectional diameter of 1.01 ± 0.26 mm (range, 0.43 to 1.74 mm; n = 67) were noted. In the linear regression model, diameter and axonal capacity demonstrated a positive relation (n = 57; r2 = 0.32; p < 0.001). Based on that equation, a nerve measuring 1 mm is expected to carry 1339 axons. The authors' analysis on the microanatomy of the frontal branch could promote clinical use of cross-facial nerve graft procedures in frontalis muscle neurotization and free muscle transplantations.

Dynamic procedures for facial nerve reconstruction

In this article the indications and surgical treatment options for patients with facial nerve palsy are discussed. A distinction is made between static and dynamic surgical procedures. Static reconstructions for example are used to restore the eyelid closure function. For smile reconstruction, which is important for the psychosocial life of the patient, dynamic procedures are used. Depending on the duration of the facial nerve paralysis, there are several possibilities to restore the smile. In this work the masseteric branch transposition to the buccal branch, the hypoglossal-facial nerve anastomosis, the Labbé procedure and the gracilis flap as a free muscle transplant are discussed. The surgical procedures are compared and the advantages and disadvantages of the intervention are presented. A spontaneous smile is aimed, this cannot always be achieved. With the masseteric branch transposition to the buccal branch and the Labbé procedure the smile is initially triggered by chewing. A spontaneous smile is possible through cortical adaptation. With the gracilis flap, however, a nerve anastomosis with the contralateral 'healthy' facial nerve is possible, either directly or via a so-called cross facial nerve grafting, whereby a spontaneous smile can be achieved.

Maximizing the Smile Symmetry in Facial Paralysis Reconstruction: An Algorithm Based on Twenty Years' Experience

Over the last two decades, the senior author (B.H.) has had an extensive experience with facial paralysis reconstruction. During this period, the techniques have evolved substantially based on the experience and after observing and analyzing the surgical outcomes. The purpose of this article is to relay the lessons learned from the 20 years' experience and suggest an algorithm. In this retrospective study, we have included 343 cases of facial paralysis cases. Complete facial paralysis cases were 285 and 58 were incomplete facial paralyses, both requiring surgical procedures. Complete facial paralyses were divided in to short term (n = 83) and long term (n = 202). In total, 58% of the patients were women and 42% were men. The age range was 6 to 82 years. The techniques employed were direct suture, nerve grafts, cross-facial nerve grafts (CFNGs), masseteric-to-facial nerve transference, hypoglossal-to-facial nerve transference, free muscle transplants, and lengthening temporal myoplasty to achieve the best symmetry after reanimation of unilateral, bilateral, complete, and incomplete facial paralysis. The type of paralysis, objective measurements, the personal patient's smile, and the gender are key concepts to be considered before scheduling a dynamic facial paralysis reconstruction. For unilateral facial paralysis, the time of onset, the type of paralysis, the patient's comorbidities, and the healthy side status are some of the determining factors when selecting the correct technique. The preferred techniques for unilateral facial paralysis are direct repair, CFNG, masseteric-to-facial transposition, and free gracilis transfer. For incomplete facial paralysis, the masseteric-to-facial nerve transference is preferred. In bilateral facial paralysis, bilateral free gracilis transfer is performed in two stages using the nerve of the masseter muscle as the source of innervation. The authors provide an algorithm which simplifies facial paralysis reconstruction to achieve the greatest facial symmetry while thinking about the potential comorbidities and developing spontaneity smile according to the gender of the patient.

Holistic reconstruction of mandible defect, lower lip and chin sensation, and smile reanimation in an advanced gum cancer patient: A case report

Facial deformity, facial paralysis, and sensory loss are inevitable after some head and neck tumor resection and reconstruction, especially in high stage cancer. To overcome these obstacles, we present a case of T4a gum cancer patient (41-year-old) who received holistic reconstruction of the mandible defect via an osteo-peroneal-artery-perforator combined flap for defect coverage and cross-mental nerve graft for lower lip and chin sensation at the primary stage, followed by ipsilateral facial nerve (lower trunk) innervated gracilis functioning free muscle transplantation for facial reanimation and correction of the sunken face 3 years later. After 4.5 years of follow-up, the patient was satisfied with his appearance, and obtained a spontaneous and symmetrical smile without sensory deficit. This experience showed a possible solution to the reconstruction for complicated head and neck cancer patients.

Erratum: Effect of Degree of Arterial Inflow on a Functioning Free Muscle Transplantation in a Rat Gracilis Model.

BACKGROUND Various surgical effects have previously been studied in an attempt to improve the functional outcome of the functioning free muscle transplantation (FFMT). However, the effect of the recipient arterial inflow on the FFMT has remained uninvestigated. This study was to investigate whether or not high flow versus low flow will affect the functional outcome of FFMT. METHODS Rat's left gracilis FFMT model was devised and the nutrient arterial inflow was modified. Twenty-four Lewis rats were divided evenly into relatively high (0.071 mL/min) and relatively low (0.031 mL/min) blood flow groups (p < 0.001). The unoperated right sides served as the controls. Cases resulting in poor function were additionally grouped as functional failure group for comparison. Regular swimming exercise was implemented at 1 month postoperatively for 3 months. Gracilis muscle functions were then evaluated. RESULTS Compared groups were: control (n = 13), low blood flow (n = 10), high blood flow (n = 8), and functional failure (n = 5). The control group showed superior functional results over the experimental groups (p < 0.0001). In the experimental group, successful group showed superior over the poor function group (p < 0.01). However, there was no significant difference between the high- and low-flow groups. CONCLUSION This is the first study to evaluate the effect of arterial inflow on the FFMT. The rate of blood flow (relatively high vs. low) has little effect on the functional outcome of transferred muscle. Survival of FFMT is the major concern while performing FFMT surgery. Arterial inflow while choosing the recipient artery is not the factor for consideration.

Functioning Free Muscle Transfer for Brachial Plexus Injury: A Systematic Review and Pooled Analysis Comparing Functional Outcomes of Intercostal Nerve and Spinal Accessory Nerve Grafts.

The aim of this study was to compare postoperative elbow flexion outcomes in patients receiving functioning free muscle transplantation (FFMT) innervated by either intercostal nerve (ICN) or spinal accessory nerve (SAN) grafts. A comprehensive systematic review on FFMT for brachial plexus reconstruction was conducted utilizing Medline/PubMed database. Analysis was designed to compare functional outcomes between (1) nerve graft type (ICN vs. SAN) and (2) different free muscle graft types to biceps tendon (gracilis vs. rectus femoris vs. latissimus dorsi). A total of 312 FFMTs innervated by ICNs (169) or the SAN (143) are featured in 10 case series. The mean patient age was 28 years. Patients had a mean injury to surgery time of 31.5 months and an average follow-up time of 39.1 months with 18 patients lost to follow-up. Muscles utilized included the gracilis (275), rectus femoris (28), and latissimus dorsi (8). After excluding those lost to follow-up or failures due to vascular compromise, the mean success rates of FFMTs innervated by ICNs and SAN were 64.1 and 65.4%, respectively. This analysis did not identify any difference in outcomes between FFMTs via ICN grafts and those innervated by SAN grafts in restoring elbow flexion in traumatic brachial plexus injury patients.

Effect of Degree of Arterial Inflow on a Functioning Free Muscle Transplantation in a Rat Gracilis Model.

Various surgical effects have previously been studied in an attempt to improve the functional outcome of the functioning free muscle transplantation (FFMT). However, the effect of the recipient arterial inflow on the FFMT has remained uninvestigated. This study was to investigate whether or not high flow versus low flow will affect the functional outcome of FFMT. Rat's left gracilis FFMT model was devised and the nutrient arterial inflow was modified. Twenty-four Lewis rats were divided evenly into relatively high (0.071 mL/min) and relatively low (0.031 mL/min) blood flow groups (p < 0.001). The unoperated right sides served as the controls. Cases resulting in poor function were additionally grouped as functional failure group for comparison. Regular swimming exercise was implemented at 1 month postoperatively for 3 months. Gracilis muscle functions were then evaluated. Compared groups were: control (n = 13), low blood flow (n = 10), high blood flow (n = 8), and functional failure (n = 5). The control group showed superior functional results over the experimental groups (p < 0.0001). In the experimental group, successful group showed superior over the poor function group (p < 0.01). However, there was no significant difference between the high- and low-flow groups. This is the first study to evaluate the effect of arterial inflow on the FFMT. The rate of blood flow (relatively high vs. low) has little effect on the functional outcome of transferred muscle. Survival of FFMT is the major concern while performing FFMT surgery. Arterial inflow while choosing the recipient artery is not the factor for consideration.

Impact of increasing age on functioning free muscle transplantation for facial palsy reconstruction.

Management of facial paralysis in older patients is controversial. The purpose of this study is to evaluate the impact of increasing age on functioning free muscle transplantation (FFMT). Twenty-nine facial paralysis patients over 50 years old received FFMT. A separate group of patients aged 41-50 years old were included as control. Outcome assessments included use of the SMILE evaluation system for excursion, a cortical adaptation scoring system for brain plasticity, and a subjective satisfaction assessment score. Meta-analysis of literature over the past 50 years was also performed to examine the impact of older age. The mean change in excursion movement was 13.39 ± 5.49 mm. Weakest excursion was found in the oldest age group (11.74 ± 4.84 mm, p = .097), in concordance with the meta-analysis. There was significant difference between the three different neurotizers (p = .036). Excursion and satisfaction score were significantly worse in the older cohort with the cross face-nerve graft FFMT. FFMT is a viable option in the elderly patient group but performs weaker in excursion. The choice of neurotizer is dependent on the patient's goals and the suitable age at which the benefits outweigh the risks.

Facial Nerve Trauma: Clinical Evaluation and Management Strategies.

The field of facial paralysis requires the reconstructive surgeon to apply a wide spectrum of reconstructive and aesthetic principles, using a comprehensive array of surgical tools, including microsurgery, peripheral nerve surgery, and aesthetic facial surgery on the road to optimize patient outcomes. The distinct deficits created by different anatomical levels of facial nerve injury require a fundamental understanding of facial nerve anatomy. Palsy duration, followed by location and mechanism, will determine mimetic muscle salvageability, by means of either direct repair, grafting, or nerve transfers, whereas longer palsy durations will necessitate introducing a new neuromuscular unit, whether by muscle transfer or free functional muscle transplant. A thorough history, physical examination, and basic understanding of ancillary studies, emphasizing palsy duration, location, and mechanism of injury, are critical in evaluation, prognostication, and treatment strategies in traumatic facial palsy patients. The importance of ancillary and aesthetic procedures cannot be overstated. Although these do not provide motion, they constitute essential tools in the treatment of facial paralysis, providing both protective and improved aesthetic outcomes, yielding the highest impact in final surgeon and patient satisfaction, bringing our patients to smile not only on the outside, but also on the inside.

A preliminary study on B -mode ultrasonic evaluation of muscle recovery after functional gracilis muscle transplantation

Objective To investigate the value of the B-mode ultrasound method for muscle recovery after transplantation. Methods From January, 2009 to January, 2014, 35 patients of functioning free gracilis muscle transplantation for brachial plexus injury were involved. Using B-mode ultrasound to determine the cross-sectional area (CSA) of transplanted gracilismuscle at rest and contraction state. The contraction ratio (CR) and the muscle bulk ratio (MBR) was calculated based on the CSA. Then the CR and MBR were analysised statistically with manual muscle strength and joint range of motion (ROM) to investigate the correlation. Results The followed-up time was 8-24 months, averaged of 22.4 months. The CR of the transplated muscle was (1.23±0.15), which was significantly correlated with muscle strength and joint ROM (P 0.05). There was no statistically significant difference in muscle strength and ROM between patients with MBR greater than 1 and those with MBR less than 1 (P= 0.054, P=0.284, respectively). Conclusion The transplanted muscle recovery can be quantitatively reflected by the CR. CR enlargement of the transplanted gracilis muscle indicated a better recovery of muscle contraction function. MBR is not suitable for evaluating function recovery of transplanted muscles. Key words: Gracilis; Functional muscle transplantation; B-mode ultrasound; Muscle contraction; Muscle strength

Segmental Gracilis Muscle Transplantation for Midfacial Animation in Möbius Syndrome: A 29-Year Experience.

Möbius syndrome is a complex congenital disorder of unclear cause involving multiple cranial nerves and typically presenting with bilateral facial and abducens nerves palsies. At The Hospital for Sick Children, Toronto, Ontario, Canada, microneurovascular transfer of free-muscle transplant is the procedure of choice for midfacial animation. The primary aim of this study was to investigate surgical outcomes of the procedure in terms of complications, secondary revisions, and smile excursion gains. A retrospective 29-year review was performed using patient records from a single tertiary care center. The authors included children with Möbius syndrome who had undergone facial animation surgery with a free segmental gracilis muscle transfer and microneurovascular repair between January 1, 1985, and August 31, 2014. Smile excursion measures were obtained using the Facial Assessment by Computer Evaluation-Gram on a subset of the included patients. A total of 107 patients undergoing 197 reconstructive procedures met inclusion criteria. Most reconstructions relied on the motor nerve branch to the masseter for innervation [n = 174 (88 percent)]. Thirteen complications were reported, of which six required surgical interventions. Three revision procedures were performed: scar revision, muscle repositioning, and removal of infected permanent suture material. The use of the motor nerve branch to the masseter resulted in good commissure excursion gains (average, 4.61 mm for bilateral cases and 9.34 mm for unilateral reconstructions). Midfacial animation with segmental gracilis muscle transfer for patients with Möbius syndrome provides gains in the amplitude and symmetry of oral commissure excursion and carries a reasonably low complication rate. Therapeutic, IV.

Pre-operative masseter muscle EMG activation during smile predicts synchronicity of smile development in facial palsy patients undergoing reanimation with the masseter nerve: A prospective cohort study✰

Synchronicity of the oral commissure movement of a bilateral smile is a significant goal for reconstruction in facial reanimation and may only be guaranteed with use of the facial nerve as a donor nerve. Yet over the years several studies report some degree of spontaneity in certain patients when using a non-facial donor nerve, which indicates that synchronous initiation of the smile might be achievable with other donor nerves. We designed a prospective cohort study to evaluate whether pre-operative involuntary activation of the masseteric nerve during smile predicts development of a synchronous smile development when using the masseteric nerve for reanimation. In a prospective cohort study unilateral long-standing facial palsy patients scheduled for dynamic smile reanimation with a free functional muscle transplant using the masseteric nerve as a donor nerve were preoperatively evaluated via EMG for involuntary activation of the masseter muscle upon smiling, which we called coactivation. Postoperatively, six months after noting the first muscle contraction smile synchronicity was evaluated. We analyzed the synchronicity of the bilateral smile development by analyzing slow-motion video sequences of the patients that were taken while the patients were watching funny video sequences. Results were then correlated with the pre-operative EMG. 30 patients were recruited for this prospective study and underwent facial reanimation surgery with a free gracilis transfer innervated by the masseteric nerve. 19 patients demonstrated involuntary coactivation of the masseter muscle upon smiling and 11 did not. Postoperatively all patients could demonstrate a voluntary smile. 94% of patients who had preoperative coactivation showed a synchronous movement of the oral commissure when smiling. In those patients, that did not show activation of the masseter muscle upon smiling 0% showed synchronicity. The preoperative coactivation of the masseter muscle is able to predict the outcome regarding synchronicity of the smile with a sensitivity of 99.7%, a specificity of 88.5% and 92.5% positive predictive value and 99.6% negative predictive value (p<0.001 for all). The lack of masseter co-activation with smile predicts a lack of spontaneous involuntary smile after dynamic smile reconstruction using the masseteric nerve.

Construction of Chinese peripheral nerve society and progress in repair and reconstruction of peripheral nerve injury

The peripheral nerve group of the reparative and reconstructive surgery committee (branch of Chinese association of rehabilitation medicine) was established in 1995. Major research progress has been made in the repair, regeneration, and reconstruction of peripheral nerve injury. Professor GU Yudong initiated the contralateral cervical7 root (CC7) transfer for the treatment of total brachial plexus root injury in 1986. Now this method has been applied safely and effectively for 30 years with profound progress and refinement. In addition, the repair and reconstruction of peripheral nerve injury had achieved great development such as the treatment of spastic paralysis of upper limb, CC7 transfer using a modified prespinal route, the reconstruction of bladder function after spinal cord injury, the development of acellular allograft nerve, the small gap suture technique, the functioning free gracilis muscle transplantation, and contralateral S 1 transfer which have been widely used in clinical application with good outcomes. With the progress of the biological manufacturing of peripheral nerve bio-materials and the remodeling of central nervous system after brachial plexus injury, a novel peripheral neuroscience research field was growing up. It is still a challenge for surgeons and scholars in this field to insist on the popularization and improvement of peripheral nerve repair and reconstruction by microsurgical technique, and to make efforts to transform the results of peripheral nerve research into clinical practice.