Neuroma Prevention Research Articles

Neuroma prevention by end-to-side neurorraphy: an experimental study in rats

Purpose The successful treatment of painful neuromas remains a difficult goal to attain. In this report we explore the feasibility of neuroma prevention by insertion of the proximal end of a nerve through an end-to-side neurorraphy into an adjacent mixed nerve to provide a pathway and target for axons deprived of their end organ. Methods Experiments were performed on a total of twenty 250-g Sprague-Dawley rats. Two groups of 10 animals were prepared. Group A served as an anatomic control. In group B the right saphenous nerve was transected and implanted end-to-side through an epineurial window into the tibial nerve distal to the trifurcation of the sciatic nerve. After 12 weeks the corresponding sensory neurons were identified by retrograde labeling techniques and histomorphometric analysis of the proximal and distal tibial nerve segments, and regular histology of the end-to-side site were performed. Results The results of the retrograde labeling of the corresponding sensory neuron pool of the saphenus nerve showed extensive labelling of the L1 to L3 spinal ganglions after intracutaneuous tracer application of the planta pedis. The morphology of the end-to-side coaptation site and histomorphologic analysis prove that sensory neurons penetrate the perineurial sheath and axons regenerate along the tibial Schwann cell tubes toward their targets. Conclusions Axons of a severed peripheral nerve that are provided with a pathway and target through an end-to-side coaptation will either be pruned or establish some type of end-organ contact so that a neuroma can be prevented. Whether these axons will lead to disturbing sensations such as paresthesia or dysesthesia in the newly found environment or remain silent codwellers, this experiment cannot answer. Long-term results of future clinical work will have to decide whether the prevention of the neuroma through end-to-side coaptation will be an appropriate therapy for this difficult problem.

Implantation of a nerve ending into a vein.

Neuromas can be painful and physically and psychologically disabling. Among the many methods of treatment available, translocation away from noxious stimuli, such as implantation in muscle or bone, has been used. Veins are easily available and accessible to nerves. The outcome of a nerve ending implanted into a vein and the effects of the implanted nerve on the vein have not been studied. This study evaluated neuroma prevention with a new technique that involves implanting a nerve ending into a vein. The medial branches of the right femoral nerve of 20 rats were transected at midthigh level. The distal segments were excised. The proximal segments were implanted into the femoral vein. The epineurium was sutured to the tunica adventitia using interrupted 10-0 Ethilon sutures. The left side served as controls where the proximal nerve stumps were left lying in their beds. The animals were sacrificed 12 weeks after the operation. Histologic analysis of 12 controls showed neuromas. Twelve implanted nerves showed neuromas that were smaller than those of the controls. The difference was statistically significant. The regenerated nerve fibers were found within the adventitia and muscular wall of the vein. There was no extension of nerve tissue into the vessel lumen and no thrombosis of the vein. Electron microscopic study on the other eight rats showed abnormal large myelinated fibers in the controls and in the implanted nerves. The fibers in the implanted group were degenerated.

Prevention of neuroma in elective digital amputations by utilization of neurovascular island flap

Following hand surgery, painful neuromas may impair the quality of the functional result. In planned, elective digital amputation, neuroma formation is quasi-unavoidable because the nerve is cut. Several techniques have been proposed to prevent the formation of neuroma but, in our opinion, the only logical way to avoid it, is not to cut the nerve. For this purpose, we proposed, in cases of planned, elective digital amputation, an intervention inspired by the technique described by Littler in 1956. This technique consists of isolating as an island, the pulp of the amputated finger while preserving nerve continuity of both collateral pedicles. Once the amputation is completed, in cases of distal amputation, the pulp flap is used to cover the proximal stump and, in cases of ray amputation, the nerve loop is buried after its deepithelialization between the adjacent metacarpals. Since 1990, this technique has been used for nine-planned, elective amputations in eight patients. Postoperatively, no patient has developed painful neuroma except one patient who had a painful finger preoperatively and in whom the symptoms remained unchanged postoperatively. This simple technique must be part of the therapeutic armamentarium of planned, elective digital amputations in cases with intact collateral nerves.

Clinical Implications of the Surgical Anatomy of the Sural Nerve

The exact anatomy of the sural nerve remains important for many clinical situations. To better understand this anatomy, 25 embalmed and 10 fresh cadaver pairs were studied. The origin of the common sural nerve in relation to the fibular head and its medial and lateral sural components were investigated. The lateral sural nerve was absent in 4 percent of the embalmed cadavers. The lateral and medial sural nerves united in the popliteal fossa in 12 percent and in the lower third of the leg in 84 percent of the cadavers. A site was identified where the lateral sural and lateral cutaneous nerve of the calf pierced the deep fascia. This site was centered about the fibular head and may be viewed as a potential site of nerve compression. There is application of these findings to nerve grafting, neuroma prevention and treatment, and sural nerve biopsy.

The Painful Stump Neuroma and Its Treatment

Successful clinical management of symptomatic neuromas continues to present a challenge to the responsible surgeon. It is unexplained why some patients with neuromas are completely asymptomatic while others exhibit debilitating symptoms. Prevention of neuromas is paramount with precise attention to severed nerves following amputations and other surgical procedures. Once established, treatment of neuromas consists of careful patient counseling, local massage, and desensitization procedures. Sympathetic blockade with guanethidine may be beneficial in some patients. When necessary, surgical excision of the neuroma along with a combination of funiculectomy, epineurial sleeve suture ligation, and silicone capping offers the best chance for eradication. In intractable or recurrent cases and following careful patient selection, neuroma excision followed by nerve grafting combined with sympathetic blockade using guanethidine can be successful in a significant number of cases.

Surgical repair of facial nerve branches. An analysis of different sheathing and suturing techniques.

The distal branches of the facial nerve are sometimes severed in various forms of trauma. These distal branches respond to repair differently than do the main trunk or other peripheral nerves. Actual axon counts must be done to determine the percentage of regrowth rather than measuring nerve diameter. Physiologic and histologic techniques were used to analyze sheathing and suturing techniques in the repair of facial nerve branches in rabbits. Repair sites were examined at various intervals up to four months after repair. Very small suture material (10-0) must be used. Vein sheaths caused decreased axon regrowth, and strictures occurred when silicone elastomer sheaths were used. Seven stitches provided the best results in terms of axon regrowth, prevention of neuromas, and return of function. Three sutures or a continuous stitch produced poorer overall results.