Neuroma formation occurs because of some degree of nerve injury followed by improper intrinsic nerve repair. The cause of neuroma pain is incompletely understood, but appears to be multifactorial in nature, including local and system changes. A comprehensive understanding of nerve anatomy, injury, and repair techniques should be used when dealing with neuroma formation and its physical manifestations. Diagnosis of neuroma is clinically characterized by pain associated with scar, altered sensation within the given nerve distribution, and a Tinel sign. The pathophysiology of neuroma formation is reviewed.

We investigated the cutaneous innervation of the distal palm, an area frequently dissected by the hand surgeon. Ten (five paired) fresh-frozen cadaveric hands were dissected under 3.0× loupe magnification. Volar branches were found on both sides in the majority of digits. They originated alongside, or at the proximal margin of, the A1 pulley in 84% of digits. The mean distance from the palmar digital crease to the origin of volar branches was 21 mm.

In the field of nerve repair, one major challenge is the formation of neuroma. However, reports on both the promotion of nerve regeneration and prevention of traumatic neuroma in the clinical settings are rare in the field of nerve repair. One of the reasons could be the insufficiency in the follow-up system. We have conducted 33 cases of nerve repair using PRGD/PDLLA/β-TCP conduit without any sign of adverse reaction, especially no neuroma formation. Among them, we have selected two cases as representatives to report in this article. The first case was a patient with an upper limb nerve wound was bridged by PRGD/PDLLA/β-TCP conduit and a plate fixation was given. After nearly 3-years\' follow-up, the examination results demonstrated that nerve regeneration effect was very good. When the reoperation was performed to remove the steel plate we observed a uniform structure of the regenerated nerve without the formation of neuroma, and to our delight, the implanted conduit was completely degraded 23 months after the implantation. The second case had an obsolete nerve injury with neuroma formation. After removal of the neuroma, the nerve was bridged by PRGD/PDLLA/β-TCP conduit. Follow-up examinations showed that the structure and functional recovery were improved gradually in the 10-month follow-up; no end-enlargement and any other abnormal reaction associated with the characteristic of neuroma were found. Based on our 33-case studies, we have concluded that PRGD/PDLLA/β-TCP nerve conduit could both promote nerve regeneration and prevent neuroma formation; therefore, it is a good alternative for peripheral nerve repair.

Melatonin has many different roles in the human body, including its importance in circadian rhythms, sleep physiology, mental status, reproduction, tumour development, ageing, and many other physiologic processes. Although there are more than hundreds of studies on effects of melatonin in several tissues, its effects on peripheral nerve has been documented in a limited number of studies. This paper focused to review the available literature in terms of several actions and effects of melatonin (beneficial or toxic effects) on well-known peripheral nerve injury models.