Tension in Peripheral Nerve Suture

"Forrester-Brown, Maud Frances, (died 12 Jan. 1970), Emeritus Consultant, Bath and Wessex Orthopædic Hospital, etc; research on peripheral nerve suture, Wilkie Department, Edinburgh University; Member of International Orthopædic Society; Vice-Chairman, Scottish Association of Sport and Medicine; Emeritus Fellow: British Orthopædic Association; Royal Society of Medicine" published on by Oxford University Press.

Erik Moberg pioneered the idea of validating measures of sensory function following peripheral nerve suture by correlating their results with those of functional tests. However it is important that powerful prior variables (age at suture, time elapsed since suture and delay between injury and suture) be controlled. Failure to do this may result in spurious correlations, as illustrated by analysis of two sets of data, one collected by the author and the other given in the classic paper of Onne (1962).

Funicular orientation by electrical stimulation and internal neurolysis in peripheral nerve suture

The final chapter on the results of peripheral nerve suture has not been written. Continued interest of investigators in this area will probably lead to improve results in the future. The biology of repair remains a determining factor once meticulous technique has been exercised by the surgeon. Epineurial neurorrhaphy is the standard technique today for peripheral nerve suture.

{\it Purpose:} To improve functional recovery after peripheral nerve suture, we characterized the quality of target reinnervation in rats in which the afferent trigeminal connection to facial motoneurons had been altered. {\it Methods:} Employing an improved lesion model and a refined mode of retrograde tracer application, we studied the accuracy of reinnervation in rats which underwent buccal-buccal nerve anastomosis (BBA) alone (group 1), BBA plus excision of the ipsilateral infraorbital nerve (ION; group 2), and BBA plus excision of the contralateral ION (group 3). This was done by comparison between the number of double-labeled motoneurons after pre-operative injection of Fluoro-Gold (FG) and post-operative injection of Fast Blue (FB) into the whisker pad muscles. {\it Results:} In the first group we counted 398 ± 80 FG+FB double labeled cells (mean ± SD; n=9 rats), i.e., only 27% of all motoneurons that grew axons into the whisker pad had projected to these muscles before surgery. In group 2, this value was increased marginally to 436 ± 68 (32%). In group 3,. we counted 580 ± 63 double-labeled neurons. This is the first morphological report demonstrating significantly improved specificity of reinnervation. Indeed, 41% of the motoneurons innervating the target in group 3 belonged to the original neuron pool. These morphological findings are supported by evidence obtained from electrophysiological recordings and behavioural studies. {\it Conclusions:} The principle finding of the present study is that a peripheral lesion to the contralateral trigeminal nerve improves the quality of reinnervation of the whisker pad musculature by its original nerve. The contralateral trigeminal lesion may trigger behavioural demand and forced overuse of the axotomized facial nerve, which may be a key issue for recovery of vibrissae rhythmical whisking after facial nerve surgery.

THE SURGERY OF THE PERIPHERAL NERVES.

Motor Cortex Stimulation Regenerative Effects in Peripheral Nerve Injury: An Experimental Rat Model.

An analysis of primary epineural end to end sutures of transsected peripheral nerves, operated upon before 1970, showed good motor and sensory function in only 60%. With the new perineural suturing technique without tension and if necessary by using autologous nerves for bridging large nerve defects the good results raised to 87%.

Tension on an end-to-end nerve suture causes injury to the intraneural vessels. Impairment of the transverse anastomoses occurs first, followed by degeneration of the intrafascicular vessels. The the transverse anastomoses undergo complete degeneration, and the extrafascicular vessels also sustain severe damage. This series of circulatory disturbances is an important factor to consider when determining the advisability of an end-to-end nerve suture.

Secondary suture of ulnar and median nerves

Transection and reanastomosis of the facial nerve with microsurgical sutures in rats (facial-facial anastomosis) results in the complete regeneration of the facial nucleus, whereas resection of a 10 mm length of the peripheral facial nerve leads to degeneration and loss of neurons in the nucleus. Nerve sutures or resections were performed in 84 female Wistar rats, and the time course and differences between regenerative and degenerative reactions in the facial nuclei were compared after survival times of 4-112 days. The volume of the facial nucleus, number of facial motoneurons and motoneuron density were estimated stereologically by the physical dissector method. Synaptic plasticity, activation of astroglia and microglia were studied cytochemically with anti-synaptophysin, anti-glial fibrillary acidic protein and the isolectin Griffonia simplicifolia I-B4 (GSA I-B4). After facial-facial anastomosis the volume of the facial nucleus and its number of motoneurons remained constant, whereas resection of the facial nerve caused shrinkage of the facial nucleus and loss of one-third of facial motoneurons within 112 days post-operation. Synaptic stripping, activation of microglia and astroglia occurred in the same sequence and were reversible after both operations, but these reactions were more severe and prolonged after resection, i.e. without suture of the facial nerve. It appears to be most important clinically that differences between de- and regeneration become clear within 7 days post-axotomy. Our results strongly support reconstruction of the facial nerve as early as possible after a nerve lesion.

The occurrence of changes within the spinal cord over a long period after a peripheral nerve injury was investigated in adult cats. The lateral superficial branch of the radial nerve was exposed and transsected unilaterally. In one group the nerve endings were re-approximated with epineural sutures and in the other group the proximal nerve stump was enclosed to prevent regeneration. After a survival period of 4-17 months the same nerve on both sides was exposed to an intra-axonal nerve tracer, lectin-conjugated horseradish peroxidase, to label the nerve terminals within the spinal gray matter by transganglionic transport. The general distribution of the terminal field was almost the same after suturing as after encapsulation of the transsected nerve, except for a slightly more cranial location of the terminal area after suturing compared with the control side. The terminal area comprised laminae I-IV of the fifth cervical to the first thoracic spinal segment, concentrated towards the sixth to eighth cervical segments. This distribution was the same as on the control side, but the experimental and control sides differed in intensity of terminals. There was a loss of terminals throughout the terminal field in both operated groups, but after nerve suture there was some recovery of terminal intensity between 4 and 17 months after the injury.

NERVE suture is still a field of surgery in which results often fall short of goals. The difficulties in the evaluation of results have been elucidated by the methods for the examination of the reg...

The post-traumatic neuro-anastomosis must be protected from the surrounding environment. This barrier must be biologically inert, biodegradable, not compressing but protecting the nerve. Formation of painful neuroma is one of the major issues with neuroanastomosis; currently there is no consensus on post-repair neuroma prevention. Aim of this study is to evaluate the efficacy of neuroanastomosis performed with venous sheath to reduce painful neuromas formation, improve the electrical conductivity of the repaired nerve, and reduce the discrepancies of the sectioned nerve stumps. From a trauma population of 320 patients treated in a single centre between January 2008 and December 2011, twenty-six patients were identified as having an injury to at least one of the peripheral nerves of the arm and enrolled in the study. Patients were divided into two groups. In the group A (16 patients) the end-to-end nerve suture was wrapped in a vein sheath and compared with the group B (10 patients) in which a simple end-to-end neurorrhaphy was performed. The venous segment used to cover the nerve micro-suture was harvested from the superficial veins of the forearm. The parameters analyzed were: functional recovery of motor nerves, sensitivity and pain. RESULTS. Average follow-up was 14 months (range: 12-24 months). The group A showed a more rapid motor and sensory recovery and a reduction of the painful symptoms compared to the control group (B). The Authors demonstrated that, in their experience, the venous sheath provides a valid solution to avoid the dispersion of the nerve fibres, to prevent adherent scars and painful neuromas formation. Moreover it can compensate the different size of two nerve stumps, allowing, thereby, a more rapid functional and sensitive recovery without expensive devices.

In 33 adult cats the lateral superficial branch of the radial nerve was exposed and transsected on one side. In one group of animals (n = 22) the nerve-stumps were re-approximated with epineural sutures and in the other group (n = 11) the proximal nerve stump was enclosed to prevent regeneration. After survival periods ranging from 4-17 months the same nerve on both sides was exposed to an intra-axonal nerve tracer to label the dorsal root ganglion neurones projecting into the nerve being investigated. In each animal the opposite side was used as control. When the transsection was followed by a nerve suture the mean proportion of labelled sensory neurones in the dorsal root ganglion, compared with the control side, was 61% at eight months after operation, but by 17 months it had increased to 70%. When regeneration was prevented by the proximal nerve stump being enclosed in a plastic envelope, the reduction in labelled cells was 45% after a survival period of 17 months.