Contralateral medial pectoral nerve transfer with free gracilis muscle transfer in old brachial plexus palsy.

BACKGROUND: There is a very small chance of success for nerve reconstruction in patients with old total brachial plexus palsy who visit after 2 y or suffer from flail upper extremity after the failure of previous operations. MATERIALS AND METHODS: For these individuals, the surgeon has to find a recipient motor nerve to perform free gracilis muscle transplantation. In this study, contralateral medial pectoral nerve from the intact side was transferred to the damaged side as a recipient nerve. Then, in the second operation, approximately 15 mo later, the free gracilis muscle transfer was performed. The gracilis muscle was removed and transferred to provide elbow and finger flexion. RESULTS: In a retrospective study (over 10 y), we reviewed 68 patients for whom this method had been performed. After 1 y, the results were investigated using the Medical Research Council grading system. Five patients did not participate in the study, and the muscle underwent necrosis in two patients. M3 and M4 muscle power was regained in 26 (42.6%) and 21 (34.4%) patients, respectively. CONCLUSIONS: Contralateral pectoral nerve transfer followed by free muscle transplantation can be a good option for patients with old total brachial plexus palsy.

A Simple Dynamic Strategy to Deliver Stem Cells to Decellularized Nerve Allografts.

BACKGROUND: The addition of adipose-derived mesenchymal stromal cells to decellularized nerve allografts may improve outcomes of nerve reconstruction. Prior techniques used for cell seeding are traumatic to both the mesenchymal stromal cells and nerve graft. An adequate, reliable, and validated cell seeding technique is an essential step for evaluating the translational utility of mesenchymal stromal cell-enhanced decellularized nerve grafts. The purpose of this study was to develop a simple seeding strategy with an optimal seeding duration. METHODS: A dynamic bioreactor was used to seed rat and human mesenchymal stromal cells separately onto rat and human decellularized nerve allografts. Cell viability was evaluated by MTS assays and cellular topology after seeding was determined by scanning electron microscopy. Cell density and distribution were determined by Live/Dead assays and Hoechst staining at four different time points (6, 12, 24, and 72 hours). The validity and reliability of the seeding method were calculated. RESULTS: Cells remained viable at all time points, and mesenchymal stromal cells exhibited exponential growth in the first 12 hours of seeding. Seeding efficiency increased significantly from 79.5 percent at 6 hours to 89.2 percent after 12 hours of seeding (p = 0.004). Both intrarater reliability (r = 0.97) and interrater reliability (r = 0.92) of the technique were high. CONCLUSIONS: This study describes and validates a new method of effectively seeding decellularized nerve allografts with mesenchymal stromal cells. This method is reproducible, distributes cells homogenously over the graft, and does not traumatize the intraneural architecture of the allograft. Use of this validated seeding technique will permit critical comparison of graft outcomes.

Donor nerve sources in free functional gracilis muscle transfer for elbow flexion in adult brachial plexus injury.

BACKGROUND: With complete plexus injuries or late presentation, free functional muscle transfer (FFMT) becomes the primary option of functional restoration. Our purpose is to review cases over a 10-year period of free functioning gracilis muscle transfer after brachial plexus injury to evaluate the effect of different donor nerves used to reinnervate the FFMT on functional outcome. METHODS: A retrospective study from April 2001 to January 2011 of a single surgeon's practice was undertaken. During this time period 22 patients underwent FFMT at Washington University in St Louis, Missouri for elbow flexion. RESULTS: Thirteen patients for whom FFMT was performed for elbow flexion met all of the requirements for inclusion in this study. Average time from injury to first operation was 12.8 months (range 4-60), and average time from injury to FFMT was 29 months (range 8-68). Average follow-up was 31.8 months (range 11-84). The nerve donors utilized included the distal accessory nerve, intercostal with or without rectus abdominis nerves, medial pectoral nerves, thoracodorsal nerve, and flexor carpi ulnaris fascicle of ulnar nerve. Functional recovery of elbow flexion was measured using the MRC grading system which showed 1 M5/5, 5 M4, 4 M3, and 3 M2 outcomes. CONCLUSION: Intraplexal donor motor nerves if available will provide better transferred muscle function because they are higher quality donors closer to the muscle and can be done in one stage without a nerve graft. Otherwise, intercostal, rectus abdominis, or the distal accessory nerve should be used in a staged fashion. © 2016 Wiley Periodicals, Inc. Microsurgery 37:377-382, 2017.

Lateral pectoral nerve transfer for spinal accessory nerve injury.

Spinal accessory nerve (SAN) injury results in loss of motor function of the trapezius muscle and leads to severe shoulder problems. Primary end-to-end or graft repair is usually the standard treatment. The authors present 2 patients who presented late (8 and 10 months) after their SAN injuries, in whom a lateral pectoral nerve transfer to the SAN was performed successfully using a supraclavicular approach.

Radial free forearm flap versus pectoralis major pedicled flap for reconstruction in patients with tongue cancer: Assessment of quality of life

BACKGROUND: This study investigated the quality of life of Chinese patients with tongue cancer who had undergone immediate flap reconstruction surgery. In addition, we compared 2 groups of patients: those who had received radial forearm free flap (RFFF) surgery and others who had received pectoralis major myocutaneous flap (PMMF) surgery. MATERIAL AND METHODS: Patients who received RFFF or PMMF reconstruction after primary tongue cancer treated with total and subtotal tongue resection were eligible for the current study. The patients' demographic data, medical history, and quality of life scores (14-item Oral Health Impact Profile (OHIP-14) and the University of Washington Quality of Life (UW-QOL) questionnaires) were collected. RESULTS: A total of 41 of 63 questionnaires were returned (65.08%). There were significant differences between the 2 groups in the gender (p< .05). Patients reconstructed with RFFF performed better in the shoulder domains, in addition to worse appearance domains. CONCLUSIONS: Using either RFFF or PMMF for reconstruction of defects after tongue cancer resection significantly influences a patient's quality of life. Data from this study provide useful information for physicians and patients during their discussion of reconstruction modalities for tongue cancers

Intercostal and pectoral nerve transfers to re-innervate the biceps muscle in obstetric brachial plexus lesions.

In obstetric brachial plexus lesions with avulsion injury, nerve grafting for biceps muscle re-innervation may not be possible owing to the unavailability of a proximal stump. In such cases, the intercostal nerves or medial pectoral nerve can serve as donor nerves in an end-to-end transfer to the musculocutaneous nerve. The present study reports the results of both techniques from a single institution in a consecutive series of 42 patients between 1995 and 2008. From 1995 to 2000 we always used the intercostal nerve transfer, and from 2001 to 2008 both techniques were used. Biceps muscle force ≥ Medical Research Council Grade 3 was achieved in 37 of 42 patients after a mean follow-up of 44 months. There was no statistical difference in the results in the medial pectoral nerve transfer group (n = 25) and the intercostal nerve transfer group (n = 17).

Reinnervation of segmented latissimus dorsi muscle with the distal stump of the thoracodorsal nerve: A preliminary experimental study in rats.

To date, nerve stumps have been dissected at the proximal side of the donor muscle for reinnervation of the muscle in free neurovascular muscle transfer. Herein, we examined the use of the distal thoracodorsal nerve, dissected from the muscle belly at the distal side of the latissimus dorsi muscle, for the reinnervation of muscle. The rat right latissimus dorsi muscle was employed as the model for our study. Twenty Wistar rats were used in this study. A rectangular muscle segment was dissected with the distal stump of dominant thoracodorsal nerve. After rotation of muscle, the distal nerve stump was sutured to a severed proximal recipient thoracodorsal nerve (n = 5). The degree of reinnervation through the distal nerve stump was compared with control groups that received proximal-to-proximal nerve sutures (n = 5), nerves that were not severed (n = 5), and severed nerves that were not sutured (n = 5) using electrophysiological, histological, and muscular volume assessments. Reinnervation of the distal nerve stump was confirmed by the contraction of the muscle following electrical stimulation and electromyography. Crossing of axons into motor endplates was confirmed by histology. Results of these assays were similar to that of the proximal nerve suture group. The volume of muscle in the distal nerve suture group was not significant different from that of the proximal nerve suture group (P = 0.63). It was demonstrated that the distal stump of the thoracodorsal nerve can be used to innervate segmented latissimus dorsi muscle. This novel procedure for the reinnervation of transplanted muscle deserves further investigations.

Reanimation of elbow extension with medial pectoral nerve transfer in partial injuries to the brachial plexus.

OBJECT: Recent advancements in operative treatment of the brachial plexus authorized more extensive repairs and, currently, elbow extension can be included in the rank of desirable functions to be restored. This study aims to describe the author's experience in using the medial pectoral nerve for reinnervation of the triceps brachii in patients sustaining C5-7 palsies of the brachial plexus. METHODS: This is a retrospective study of the outcomes regarding recovery of elbow extension in 12 patients who underwent transfer of the medial pectoral nerve to the radial nerve or to the branch of the long head of the triceps. RESULTS: The radial nerve was targeted in 3 patients, and the branch to the long head of the triceps was targeted in 9. Grafts were used in 6 patients. Outcomes assessed as Medical Research Council Grades M4 and M3 for elbow extension were noted in 7 (58%) and 5 (42%) patients, respectively. CONCLUSIONS: The medial pectoral nerve is a reliable donor for elbow extension recovery in patients who have sustained C5-7 nerve root injuries.

Transfer of pectoral nerves to suprascapular and axillary nerves: an anatomic feasibility study.

PURPOSE: We conducted an anatomic study to provide detailed information on the pectoral nerves and anatomic data on the transfer of the pectoral nerves to the axillary nerve. Moreover, we experimentally determined the feasibility of transferring the pectoral nerves to the suprascapular nerve in upper brachial plexus injury. METHODS: We dissected 26 brachial plexus from 15 fresh cadavers. The origin, location, course, and branching of the pectoral nerves were recorded. The length and the diameter of the pectoral nerves were measured. The diameter of the suprascapular and axillary nerves was recorded. In all dissections, we assessed the feasibility of directly transferring the pectoral nerves to the suprascapular and axillary nerves. RESULTS: We found 3 constant branches of pectoral nerves arising from 3 distinct origins in 20 cases, and 3 constant branches arising from 2 distinct origins in 6 cases. The C7 sent nerve fibers to all 3 branches. The average length and diameter of the superior, middle, and inferior branches of the pectoral nerves were 65 mm, 110 mm, and 105 mm, and 2.0 mm, 2.3 mm, ad 2.4 mm, respectively. The average diameter of the suprascapular and axillary were 2.8 mm and 3.6 mm, respectively. The superior branch reached the suprascapular and axillary nerves in 17 and 8 cases. The middle and inferior branches reached the suprascapular and axillary nerve in all dissections. CONCLUSIONS: With an adequate length, diameter, and nerve composition, the middle and inferior branches of the pectoral nerves are suitable donor nerves to the axillary nerve and a potential source of reinnervation of the suprascapular nerve in upper brachial plexus injury.

The contralateral long thoracic nerve as a donor for upper brachial plexus neurotization procedures: cadaveric feasibility study.

OBJECT: Various donor nerves, including the ipsilateral long thoracic nerve (LTN), have been used for brachial plexus neurotization procedures. Neurotization to proximal branches of the brachial plexus using the contralateral long thoracic nerve (LTN) has, to the authors' knowledge, not been previously explored. METHODS: In an attempt to identify an additional nerve donor candidate for proximal brachial plexus neurotization, the authors dissected the LTN in 8 adult human cadavers. The nerve was transected at its distal termination and then passed deep to the clavicle and axillary neurovascular bundle. This passed segment of nerve was then tunneled subcutaneously and contralaterally across the neck to a supra- and infraclavicular exposure of the suprascapular and musculocutaneous nerves. Measurements were made of the length and diameter of the LTN. RESULTS: All specimens were found to have a LTN that could be brought to the aforementioned contralateral nerves. Neural connections remained tension free with left and right neck rotation of approximately 45 degrees . The mean length of the LTN was 22 cm with a range of 18-27 cm. The overall mean diameter of this nerve was 3.0 mm. No gross evidence of injury to surrounding neurovascular structures was identified in any specimen. CONCLUSIONS: Based on the results of this cadaveric study, the use of the contralateral LTN may be considered for neurotization of the proximal musculocutaneous and suprascapular nerves.

Clinical application of pectoral nerve transfers in the treatment of traumatic brachial plexus injuries.

PURPOSE: To determine the effectiveness, reliability and donor site morbidity of pectoral nerve transfers in the treatment of brachial plexus lesions. METHODS: This retrospective study included 6 patients with 7 pectoral nerve transfers. The follow-up examination comprised measurement of the ranges of motion (AO neutral-0 method), functional muscle testing (British Medical Research Council), and photo- and videographic documentation. RESULTS: Three patients achieved excellent results (M5, M4), in 3 cases good muscle function was achieved (M3) and 1 patient, who had a short follow-up period, revealed M2 motor function. CONCLUSIONS: This study describes the treatment of patients with conditions far from ideal. All patients sustained extensive brachial plexus lesions and most had severe associated injuries of the upper limb, which limited the availability of sufficient donor nerves. Despite these facts, 6 cases had excellent or good results and 1 showed continuing improvement of muscle function. These good results and the excellent results documented in literature demonstrate the high dependability and efficiency of the pectoral nerves as donors in the treatment of brachial plexus lesions. Furthermore, it was shown that free functioning muscle transplants can be sufficiently reinnervated by pectoral nerves. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Regenerating motor bridge axons refine connections and synapse on lumbar motoneurons to bypass chronic spinal cord injury.

To restore motor control after spinal cord injury requires reconnecting the brain with spinal motor circuits below the lesion. A bridge around the injury is an important alternative to promoting axon regeneration through the injury. Previously, we reported a novel motor bridge in rats. The thirteenth thoracic nerve was detached from the muscle it innervates and the cut end implanted caudally into the lumbar gray matter where motor bridge axons regenerate. In this study, we first determined that regenerating bridge axons project to spinal motor circuits. Stable projections were present in ventral motor laminae of the cord, including putative synapses directly on motoneurons, 2 months after insertion in the intact cord. At this time, earlier-forming dorsal horn projections were mostly eliminated. Regenerating axons were effective in evoking leg motor activity as early as 2 weeks. We next determined that bridge axons could regenerate caudal to a chronic injury. We hemisected the spinal cord at L2 and inserted the bridge nerve 1 month later at L5 and found ventral laminae projections similar to those in intact animals, including onto motoneurons directly. Finally, we determined that the bridge circuit could be activated by neural pathways rostral to its origin. For spinally hemisected animals, we electrically stimulated the rostral spinal cord and recorded evoked potentials from the bridge and, in turn, motor responses in the sciatic nerve. Our findings suggests that bridge motoneurons could be used by descending motor pathways as premotor interneurons to transmit neural signals to bypass a chronic spinal injury.

Temporary innervation of a primary coverage muscle: a new technique to optimize function in a subsequent functional microvascular muscle transplant.

The author describes the simple technique of innervating the coverage muscle in the staged reconstruction of an upper-extremity crush-avulsion injury with a functional microvascular muscle transplant (FMMT). The thoracodorsal nerve was repaired to the mixed motor-sensory radial nerve above the elbow. Contraction of the latissimus muscle at 8 months after nerve repair signaled the adequacy of the 10-cm thoracodorsal nerve graft as a target motor nerve for the eventual FMMT. Excursion of the latissimus muscle created a septo-alveolar plane similar to the plane between two healthy muscles into which the FMMT could be placed. The author also discusses the potential advantages of early thoracodorsal nerve repair for successful nerve regeneration. This simple technique helped overcome the potential limitations to functional muscle transplantation in the severely traumatized upper extremity, and deserves applied study.

Bridge over troubled waters.

Spinal cord injury interrupts connections between the brain and spinal cord, rather than producing large-scale damage. Reconnecting severed axons with their prior targets is a primary objective of spinal cord repair. Despite progress, this goal will probably not be attained soon because many problems remain to be solved. We discuss an alternative for promoting motor function after spinal damage by bridging the injury. We highlight a novel spinal injury bridge that we have developed to reconnect spinal motor circuits below the injury with the brain. A spinal nerve that exits above the injury is disconnected and inserted into the cord caudal to injury. Motor axons in the inserted nerve regenerate into the cord and synapse on neurons producing a novel circuit to bypass the injury.

Engineering novel spinal circuits to promote recovery after spinal injury.

We have developed an innovative way to establish a functional bridge around a spinal lesion. We disconnected the T13 nerve from its muscle targets, leaving the proximal end intact. The cut end was inserted either into an intact spinal cord, to assess regeneration of T13 axons into the cord and synapse formation with spinal neurons, or caudal to a hemisection at L2/3, to assess restoration of function below the injury. Four to 28 weeks later, anterograde tracers indicated that axons from the inserted T13 nerve regenerated into the ventral horn, the intermediate zone, and dorsal horn base, both in intact and hemisected animals. Antibodies to cholinergic markers showed that many regenerating axons were from T13 motoneurons. Electrical stimulation of the T13 nerve proximal to the insertion site 4 weeks or more after insertion into the intact cord evoked local field potentials in the intermediate zone and ventral horn, which is where T13 axons terminated. Stimulation of T13 in 71% of the animals (8 hemisected, 7 intact) evoked contraction of the back or leg muscles, depending on the level of insertion. Animals in which T13 was inserted caudal to hemisection had significantly less spasticity and muscle wasting and greater mobility at the hip, knee, ankle, and digits in the ipsilateral hindlimb than did animals with a hemisection only. Thus, T13 motor axons form novel synapses with lumbosacral motor circuits. Because the T13 motor neurons retain their connections to the brain, these novel circuits might restore voluntary control to muscles paralyzed below a spinal lesion.

Transfer of pectoral nerves to the musculocutaneous nerve in obstetric upper brachial plexus palsy.

OBJECTIVE: To investigate the results of transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric brachial palsy. METHODS: In 25 cases of obstetric brachial palsy (20 after breech deliveries), branches of the pectoral nerve plexus were transferred directly to the musculocutaneous nerve. For all patients, the nerve transfer was part of an extended brachial plexus reconstruction. Results were tested both clinically and with the Mallet scale, at a mean follow-up time of 70 months (standard deviation, 34.3 mo). RESULTS: There were two complete failures, which were attributable to disconnection of the transferred nerve endings. The results after transfer were excellent in 17 cases and fair in 5 cases. Steindler flexorplasty improved elbow flexion for three patients. CONCLUSION: Transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric upper brachial palsy may be effective, if the specific anatomic features of the pectoral nerve plexus are sufficiently appreciated.

Patient outcome following a thoracodorsal to musculocutaneous nerve transfer for reconstruction of elbow flexion.

This study reports patient outcome following a thoracodorsal to musculocutaneous nerve transfer. We retrospectively reviewed the charts of six patients who had undergone transfer of the thoracodorsal nerve to the musculocutaneous nerve for reconstruction of elbow flexion. The mean age was 47 years (standard deviation: 24 years; range: 17-72 years). The mean time from injury to surgery was 3 months (standard deviation: 2 months; range: 1-5 months). In all cases, the biceps muscle was successfully reinnervated; in one case the Medical Research Council (MRC) muscle grade was grade 5, in four cases it was grade 4, and in one case it was grade 2. No patients complained of functional weakness with shoulder adduction and/or internal rotation. In the majority of cases, transfer of the thoracodorsal nerve to the musculocutaneous nerve provides excellent recovery of elbow flexion.

Transfer of the medial pectoral nerve: myth or reality?

OBJECTIVE: Transfer of the medial pectoral nerve is one of the most controversial procedures used to reinnervate the paralyzed upper arm because of brachial plexus spinal nerve root avulsion or directly irreparable proximal lesions of spinal nerves. The purpose of this study was to determine the value of this type of nerve transfer to the musculocutaneous and axillary nerves. METHODS: The 25 patients included in the study comprised 14 patients who had nerve transfer to the musculocutaneous nerve and 11 who underwent nerve transfer to the axillary nerve. These patients' functional recovery and the time course of their recovery were analyzed according to the type of transfer of one donor nerve or the donor nerve in combination with other donors. RESULTS: Useful functional recovery was achieved in 85.7% of patients who had nerve transfer to the musculocutaneous nerve and in 81.8% of patients who underwent nerve transfer to the axillary nerve. There was no significant difference in results with regard to the type of nerve transfer and which recipient nerves were involved. A strong trend toward better results after procedures involving the use of a donor nerve combined with other donors was observed, however. CONCLUSION: Our surgical results suggest that the transfer of the medial pectoral nerve to the musculocutaneous nerve and also to the axillary nerve may be a reliable and effective procedure.

Nerve harvesting procedures.

Autogenous nerve grafts currently set the standard for reconstruction of motor and sensory nerve injuries that cannot be repaired by mobilization, advancement, and approximation, and suturing without tension. Donor nerves such as the GAN and SN are easily accessible and frequently used in maxillofacial microneurosurgery. Other nerves (MACN, LCNF, LTN) may serve well in special nerve reconstruction situations. In the future, availability of biodegradable nerve conduits with neurotrophic factors may render obsolete the reconstruction of the short-span nerve gap (< 3 cm) by autogenous nerve grafts.

Neuronal structure of microvascular transplants with and without neuronal anastomosis.

OBJECTIVE: Latissimus dorsi transplants have little neuronal regenerative capacity without neuronal anastomosis. Histologic differences between transplants with and without neuronal anastomosis and 2 distinct types of neurosurgical reanastomosis are highlighted in this study. PATIENTS AND METHODS: Fifty-four patients with squamous cell carcinomas of the oral cavity (T4) were treated by tumor resection and homolateral neck dissection. The defect was covered with a microvascular latissimus dorsi transplant. In 15 patients, no neuronal anastomoses were performed. In 21 patients, the thoracodorsal nerves were used for microneurosurgical reanastomosis, whereas in 18 patients, the cutaneous branches of the intercostal nerves were used for microneurosurgical reanastomosis. The transplant was examined during surgery and 9 months after surgery by means of a histologic examination of a biopsy specimen. The number of fascicles, the degree of fibrosis, and the myelination were examined. Furthermore, a neurosensory examination was performed 9 months after surgery. RESULTS: Overall, our patients had an average of 12.1 fascicles during surgery. After surgery, patients without neuronal anastomosis showed an average of 4.9 fascicles, patients with nerve anastomosis to the cutaneous branches of the intercostal nerve showed an average of 6.2 fascicles, and patients with anastomosis to the thoracodorsal nerve showed an average of 9.6 fascicles. In cases of nerve anastomosis, a lesser degree of fibrosis was found, together with good myelinization. The clinical examination showed the best neurosensory function in the transplants with anastomosis to the thoracodorsal nerve and the worst function in those without neuronal anastomosis. CONCLUSION: Neuronal reanastomosis led to more surviving neuronal structures in the postoperative histologic specimen. The highest density of fascicles was found in the well vascularized thoracodorsal nerve. The neurosensory function agrees with the histologic result.