End-to-side neurorrhaphy of motor nerves: reinnervation of free muscle transplants—first clinical application

End-to-side neurorrhaphy may offer a practical solution in limited cases of nerve reconstruction when no donor nerve or nerve transfer is available for direct end-to-end nerve suture, or when extremely long distances for nerve regeneration cause irreversible atrophy of the targets. We report our experience with the successful clinical use of a completely new technique of end-to-side neurorrhaphy for motor reinnervation of free functional muscle transplants. Since 1995 we have used end-to-side nerve repair for motor or sensory reinnervation in 13 cases. A free functional muscle graft was reinnervated by an end-to-side neurorrhaphy in four patients after tumor resection (two myocutaneous latissimus dorsi flaps), Volkmann's contracture (one myocutaneous latissimus dorsi flap), and in a long-standing brachial plexus lesion (one gracilis muscle flap). All four patients showed reinnervation of their muscle graft through the end-to-side nerve suture site. Two functional muscle grafts to the upper extremity had positive outcome of M3-M4 for elbow and finger extension in one case, and M4 for finger flexion in one case more than 2 years after transplantation. The transplant in the brachial plexus lesion is too early for a final functional result. One patient had a M3 for knee extension 8 months postoperatively. In the clinical cases there was no downgrading of the muscle functions supplied by the "donor" nerve. Good and clinically relevant reinnervation of a functional muscle graft is possible through an end-to-side nerve suture. Proximal avulsion, missing proximal nerve stumps, partial recovery, shortening of long distances for nerve regeneration, and prevention of long nerve grafts in proximal lesions are good indications for reinnervation of a functional muscle transplant by end-to-side neurorrhaphy without harm to the donor nerve. Donor nerves supplying synergists should be preferred.     

Is end-to-side neurorrhaphy effective? A study of axonal sprouting stimulated from intact nerves

The purpose of this study was to determine if axonal sprouting across an end-to-side coaptation could be stimulated and if so, to identify the source of the regenerating axons. Mechanical trauma, the method used to stimulate axonal sprouting, was compared to a control group with coaptation only and an additional non-grafted control group. After a 20-week recovery period, electrical stimulation revealed that the target muscles had been reinnervated in all groups except the non-grafted control group. Axonal counting demonstrated a significant increase for the mechanical trauma group compared to the control group with coaptation only [ratio of the density of axons/microm2 of the experimental to the contralateral control side: 2.78+/-0.11 vs. 0.96+/-0.15, respectively, p<0.002). Tibialis anterior muscle weights were significantly increased for both groups vs. the non-grafted control group (ratio of experimental to the contralateral control side: coaptation-only control, 0.539+/-0.024; mechanical trauma, 0.538+/-0.036 vs. nongrafted control, 0.220+/-0.003, p<0.002). Of importance, this study provides evidence that the intact tibial nerve functions as a bridge for regenerating axons derived from the proximal peroneal stump. This suggests an alternative explanation to successful end-to-side axonal sprouting, and questions the clinical utility of end-to-side coaptation.     

Nerve transfer for treatment of brachial plexus injury：comparison study between the transfer of partial median and ulnar nerves and that of phrenic and spinal accessary nerves

Objective:To compare the effect of using partial median and ulnar nerves for treatment of C5-6 orC5-7 avulsion of the brachial plexus with that of using phrenic and spinal accessary nerves.Methods:The patients were divided into 2groups randomly according to different surgical procedures.Twelve cases were involved in the first group.The phrenic nerve was transferred to the musculocutaneous nerve or through a sural nerve graft,and the spinal accessary nerve was to the suprascapular nerve.Eleven cases were classified into the second group.A part of the fascicles of median nerve was transferred to be coapted with the motor fascicle of musculocutaneous nerve and a part of fascicles of ulnar nerve was transferred to the axillary nerve.The cases were followed up from 1to 3years and the clinical outcome was compared between the two groups.     

Osmic acid staining of myelin sheath in normal and regenerated peripheral nerves

Objective: To introduce a practical, economical, and time-saving method to stain (with osmic acid) the myelin sheath in normal and regenerated peripheral nerves. Methods: A total of 12 Sprague Dawley rats, weighing 250-320 g (mean =276 g±38 g), were divided into two groups: a normal nerve group (n=6) and a regenerated nerve group (n=6). In the normal nerve group, the ventral and dorsal roots of L4 to L6 and their sciatic nerves were harvested for histological analysis. While in the regenerated nerve group, the right sciatic nerves were severed and then repaired with an epineurial microsuture method. The repaired nerves were harvested 12 weeks postoperatively. All the specimens were fixed in 4% paraformaldehyde and transferred to 2% osmic acid for 3-5 days. Then the specimens were kept in 75% alcohol before being embedded in paraffin. The tissues were cut into sections of 3μm in thickness with a conventional microtome. Results: Under a light microscope, myelin sheaths were clearly visible at all magnifications in both groups. They were stained in clear dark colour with a light yellow or colorless background, which provided high contrast images to allow reliable morphometric measurements. Morphological assessment was made in both normal and regenerated sciatic nerves. The ratios of the myelin area to the fibre area were 60. 28%±7. 66% in the normal nerve group and 51. 67%±6. 85% in the regenerated nerve group, respectively (P<0.01). Conclusions: Osmic acid staining is easy to perform and a very clear image for morphometrical assessment is easy to obtain. Therefore, it is a reliable technique for quantitative evaluation of nerve morphology.     

Primary nerve transplantation: does it make sense in defect injury of peripheral nerves?

Regeneration of damaged nerves limits the outcome of complex injuries of the upper extremities. We report the follow-up results in 7 of 10 patients over 5 years who underwent a transplantation of n. suralis in 6 cases and n. cutaneus antebrachii ulnaris in 4 cases. The average DASH-score of 30 points, no neurinoma and a protective sensibility in 5 cases are comparable with the literature.     

Identification of differentially expressed genes from spinal cord after firearm injury to rabbit sciatic nerves

GResearchInstituteofSurgery ,DapingHospital,ThirdMilitaryMedicalUniversity ,Chongqing 4 0 0 0 4 2 ,China (WangJM ,LiBC ,ChenL ,WangGBandZhangLC) Correspondingauthor:Tel:86 2 3 6 875 75 72 ,E mail:jmwang@public .cta .cq .cnThisprojectwassupportedbytheKeyStateDevelopmentProgramforBasicResearchofChina (No .19990 5 4 2 0 6 ) .eneregulationofnerveregenerationisanexcitingareainbiomedicine .Therehavebeenmanyreportsabouttheregulationgenesofperipheralnerveregeneration .Generegulationofne…     

dentification of differentially expressed genes from spinal cord after firearm injury to rabbit sciatic nerves

Objective: Peripheral nerve regeneration depends on gene regulation by central neurons. To search for more effective treatment methods to improve the regeneration of wounded peripheral nerves, gene expression profile of spinal cord after firearm injury to rabbit sciatic nerves are studied with DNA micro-array technique. Methods: A total of 54 rabbits were randomly divided into 4 groups: Groups dl, d3, d7 and normal control group. Lumbar spinal cords were sampled. RNAand mRNA were extracted, labeled by Cy3 and Cy5, and analyzed by mouse_8192S gene chips. Results: A total of 1367, 923, and 61 genes with differential expression were found on day 1, day 3, and day 7 after trauma respectively. Five expressed sequence tag (EST) sequences demonstrated differential expression during 7 days after trauma. Conclusions: There is complex gene profile with differential expression after firearm nerve injury, among which AW701496, U84291, W13926, X04017 andAW822394 EST sequences may be important regulation factors that involved in regeneration of peripheral nerve injury.     

To fabricate artificial nerves with tissue engineering methods

OBJECTIVE: To fabricate artificial nerves with tissue engineering methods in vitro. METHODS: Schwann cells (SCs) were cultured and seeded on polyglactin 910 fibers wrapped by biomembrane coated with rat tail glue and laminin for 2 weeks. The absorbability on the scaffolds, growth and migration of SCs were assessed with a light microscope, a scanning electron microscope and a transmission electron microscope. RESULTS: SCs could migrate and proliferate on polyglactin 910 fibers. They were well distributed between scaffolds and absorbed on surface of scaffolds and formed a bungner band, on which SCs produced more matrices. SCs seeded on the biomembrane could also grow well. Axon regeneration in the distal nerve stump was observed at 8 weeks. CONCLUSIONS: Adult SCs can be expanded on coated fibers and biomembrane. Three-dimensional scaffold of SCs has the basic characteristics of artificial nerves. These findings offer a novel method to fabricate artificial nerves with tissue engineering methods for repairing defected long nerves.     

A quantitative study of vibration injury to peripheral nerves—introducing a new longitudinal section analysis

Purpose

Long-term vibrations are known to cause neurovascular diseases, which are common in workers who operate handheld power tools or motor vehicles. Understanding the neuropathology of vibration-induced nerve injury is critical to its prevention and treatment. This study aims to evaluate whether light microscopy of longitudinal nerve sections can be used as a simple yet effective method for quantifying nerve injury.

Methods

The rats were split into two groups that were subjected to vibration (4 h/day) for 7 or 14 days. They were then allowed to rest for varying periods of time. Longitudinal sections of the tail nerves were examined under light microscopy. Injuries to the nerves were classified into three types, counted, tallied, and then divided by the length of the nerve being studied.

Results

Both 7 and 14 days of vibration showed significant damage when no recovery time was given. After 1 month of rest, the 7-day group began to show signs of recovery, but the 14-day group did not. After 2 months of rest, the 7-day vibration group showed almost complete recovery, while the 14-day vibration group still showed significant damage when compared to the sham control groups.

Conclusion

The amount of damage to the myelin sheath directly correlated with vibration duration. When vibrated for longer than 7 days, nerve recovery was limited. This study also demonstrated that light microscopy of longitudinal slices is a simple yet effective method of quantifying the nerve damage.     

End-to-side nerve coaptation: is an additional proximal coaptation useful when available?

The aim of this experimental study was to evaluate the effects of end-to-side coaptation of the proximal end of a severed nerve to the same intact nerve, in addition to traditional end-to-side coaptation of the distal end, with an aim to use the intact nerve as a nerve conduit in a rat model and to compare the functional and histologic results of this modality to those obtained after nerve grafting and traditional end-to-side nerve coaptation. In group A, a peroneal nerve defect measuring 1 cm was created in the left hind limb, and a nerve graft 1 cm long was used to bridge the defect. In group B, only the distal stump of the peroneal nerve was coapted to the intact tibial nerve. In group C, both ends of the peroneal nerve defect were coapted to the intact tibial nerve in an end-to-side fashion 1.5 cm apart from each other, and in group D, the peroneal nerve defect was left unrepaired. Group E was consisted of nonoperated peroneal nerves that were used to obtain normative data. Although significantly higher myelinated axon densities were observed in groups B and C compared with group A and group E, total number of the myelinated axons was significantly higher only in group C. Peroneal functional index assessments demonstrated that nerve recovery in the peroneal nerve was similar in groups A and C, and both were better than those observed in groups B and D. Collectively, these results suggest that end-to-side coaptation of both ends of a severed nerve to an intact nerve, in case of a nerve defect in this length, may serve as an alternative for nerve grafting.     

Origins of surface potentials evoked by electrical stimulation of oculomotor nerves: are they related to electrooculographic or electromyographic events?

OBJECT: Evoked potentials elicited by electrical stimulation of the oculomotor nerve and recorded from surface electrodes placed on the skin around the eyeball reportedly originate in the eye and are represented on electrooculograms. Because evoked potentials recorded from surface electrodes are extremely similar to those of extraocular muscles, which are represented on electromyograms, the authors investigated the true origin of these potentials. METHODS: Evoked potentials elicited by electrical stimulation of the canine oculomotor nerve were recorded from surface electrodes placed on the skin around the eyeball. A thread sutured to the center of the cornea was pulled and the potentials that were evoked during the resultant eye movement were recorded. These potentials were confirmed to originate in the eye and to be represented on electrooculograms because their waveforms were unaffected by the administration of muscle relaxant. To eliminate the influence of this source, the retina, a main origin of standing potentials of the eyeball, was removed. This resulted in the disappearance of electrooculography (EOG) waves elicited by eye movement. Surface potentials elicited by oculomotor nerve stimulation were the same before and after removal of the retina. Again the oculomotor nerve was electrically stimulated and electromyography (EMG) response of the extraocular muscles was recorded at the same time that potentials were recorded from the surface electrodes. In their peak latencies, amplitudes, and waveforms, the evoked potentials obtained from surface electrodes were almost identical to EMG responses of extraocular muscles. CONCLUSIONS: Evoked potentials elicited by electrical stimulation of the oculomotor nerves and obtained from surface electrodes originated from EMG responses of extraocular muscles. These evoked potentials do not derive from the eye.     

Sensory recovery after primary repair of palmar digital nerves using a Revolnerv® collagen conduit: A prospective series of 27 cases

Despite advances in microsurgery, digital nerve repair remains a challenge due to the lack of reproducible procedures with satisfactory functional results. The aim of this study was to compare the sensory and functional results of direct microsurgical sutures protected by a Revolnerv^® nerve regeneration conduit, with results of a series of direct sutures without a protective conduit in the literature. From November 2009 to April 2010, 35 patients were treated by direct epiperineural suture for digital nerve injury, protected by a Revolnerv^® nerve regeneration conduit at the FESUM centre “SOS-mains Lesquin/CHRU de Lille”. Sensory recovery was assessed by the static two-point discrimination Weber test (WS) and the Semmes-Weinstein (SW) test at postoperative months 1, 3, and 6. The final evaluation was performed after a minimum follow-up of 6 months. Statistical analysis of sensory results (WS and SW) was mainly performed with non-parametric tests (Wilcoxon, Mann and Whitney). P < 0.05 was considered to be statistically significant. One patient was excluded, six were lost to follow-up, and four could not be seen at the 6-month follow-up visit. Finally, 24 patients and 27 nerve sutures were included. Mean age was 38 years old and the ratio of women/men was 1/5. Eighty-five percent of the patients had useful (S3 + ) or normal (S4) discrimination at 6 months, and the average WS was 10.3 (± 3.76). There was a tendency to better WS results in sharp transections compared to jagged lacerations (9.19 vs 11.82). The SW test was satisfactory in 15% of patients and acceptable in 30%. There were no complications from the Revolnerv^® collagen tube. After 6 months follow-up this study shows that results with the Revolnerv^® nerve regeneration conduit on direct palmar digital nerve sutures were comparable to but not better than those of uncoated direct sutures. A study including a larger population with longer follow-up is necessary to determine the value of this technique and its recommendation for general use in all digital nerve injuries.     

Can local supply of bone marrow mononuclear cells improve the outcome from late tubular repair of human median and ulnar nerves?

The purpose of this non-randomised retrospective study was to compare nerve regeneration after reconnection with silicone tubes with two different strategies. A total of 44 patients with injured median or ulnar nerves in the forearm were surgically treated. In one group of patients, a silicone tube alone was placed in the nerve gap. In a second group, the silicone tube was filled with autologous bone marrow mononuclear cells obtained by aspiration from the iliac crest. Motor function, sensation and the effect of pain on function were assessed 1 year after surgery. The tubes filled with bone marrow cells showed better recovery than the empty tubes. The use of bone marrow mononuclear cells in addition to tube re-connection may promote better nerve regeneration than conventional tubular repair.     

Recent neuroanatomical studies on the neurovascular bundle of the prostate and cavernosal nerves： clinical reflections on radical prostatectomy

The neurovascular bundle of the prostate and cavernosal nerves have been used to describe the same structure ever since the publication of the first studies on the neuroanatomy of the lower urogenital tract of men, studies that were prompted by postoperative complications arising from radical prostatectomy. In urological surgery every effort is made to preserve or restore the neurovascular bundle of the prostate to avoid erectile dysfunction （ED）. However, the postoperative potency rates are yet to be satisfactory despite all advancements in radical prostatectomy technique. As the technology associated with urological surgery develops and topographical studies on neuroanatomy are cultivated, new observations seriously challenge the classical teachings on the topography of the neurovascular bundle of the prostate and the cavernosal nerves. The present review revisits the classical and most recent data on the topographical anatomy of the neurovascular bundle of the prostate prostatectomy techniques.