Unusual recurrence of trigeminal neuralgia after microvascular decompression by muscle interposal

A Novel Pathophysiological Mechanism Contributing to Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a form of neuropathic pain that affects the fifth cranial nerve, the most widely distributed nerve in the head. Although TN has been associated with a variety of pathological conditions, neurovascular compression on the trigeminal nerve, as it exits the brain stem, is the most frequent reported cause. This compression provides a progressive demyelination of the nerve and a subsequent aberrant neural transmission. Although several studies have clarified some physiopathological mechanisms underlying TN, the molecular basis remains vague. Very recently the substitution of methionine 136 by valine (MET126Val) in sodium channel Nav1.6 in a case study of typical TN has suggested a new possible mechanism for TN. The findings of this new mutation provide novel information that warrants further conclusive investigations.

Pterygopalatine fossa segment neurectomy of maxillary nerve through maxillary sinus route in treating trigeminal neuralgia

PURPOSE

To explore an effective surgical treatment for pain in the distribution area of the maxillary branch of trigeminal nerve (TN).

MATERIALS AND METHODS

Twenty-six patients with pain in the distribution of the maxillary branch of TN were followed up after they had undergone pterygopalatine fossa segment neurectomy of maxillary nerve through maxillary sinus route.

RESULTS

In all cases, the pain initially resolved after operation, with anaesthesia or paraesthesia in the operated side of the maxillary nerve-distributed area. After a mean follow-up period of 24 (range 3-36) months, 19 (73.08%) of the 26 patients had an excellent response, 5 (19.23%) had a good response, 2 (7.69%) had a fair response, and none (0%) had a poor response. One patient had a recurrence with palatal pain 3 months after the operation.

CONCLUSIONS

The maxillary sinus route can provide a clear vision for sectioning of the maxillary nerve. This new surgical technique has proven to be safe and effective. It provides another option for the weak elderly who are intolerant of craniotomy or patients who have contraindications for craniotomy when radiofrequency thermocoagulation (RFT) and percutaneous glycerol neurolysis (PGR) treatment is not possible.

Autologous nerve implantation into denervated monkey skin promotes regeneration of Meissner's corpuscle

Background

The aim of this study was to observe the effects of autologous nerve implantation into the denervated finger flap on the regression and regeneration of sensory nerve endings and Meissner’s corpuscles.

Material/Methods

Bilateral nerves of fingers were separated: one was removed and the other was implanted into the denervated finger in the implantation group. In the non-implantation group, both nerves were removed. The ventral skin of fingers was collected for immunohistochemistry and electron microscopy 3, 6, 9 and 12 months after surgery.

Results

The nerve endings in the Meissner’s corpuscles began to degenerate 3 months after denervation. The elementary structure of Meissner’s corpuscles was not significantly altered. Nerve fibers were present around the Meissner’s corpuscles, accompanied by growing into its inward. The axons in the denervated nerve disappeared and the Meissner’s corpuscles began to atrophy at month 6. More regenerated nerve fibers were observed after nerve implantation, including intensive and thick fibers, accompanied by reinnervation of Meissner’s corpuscles. More nerve fibers and a higher proportion of myelinated nerve fibers were noted at month 9 in the implantation group, and the reinnervation was present in the majority of Meissner’s corpuscles. Naive myelinated nerve fibers appeared at the caudal end of Meissner’s corpuscles. The nerve fibers in the Meissner’s corpuscles increased to the normal level at 12 months after nerve implantation.

Conclusions

The implanted nerve regenerated a large amount of free nerve endings, which helped to regenerate simple Meissner’s corpuscles via governing previously degenerated corpuscles.