The Role of Timing in Nerve Reconstruction

Abstract

The surgeon, who treats nerve injuries, should have knowledge about how peripheral nerves react to trauma, particularly an understanding about the extensive pathophysiological alterations that occur both in the peripheral and in the central nervous system. A large number of factors influence the functional outcome, where the surgeon only can affect a few of them.In view of the new knowledge about the delicate intracellular signaling pathways that are rapidly initiated in neurons and in non-neuronal cells with the purpose to induce nerve regeneration, the timing of nerve repair and reconstruction after injury has gained more interest. It is crucial to understand and to utilize the inborn mechanisms for survival and regeneration of neurons and for activation, survival and proliferation of the Schwann cells and other cells that are acting after a nerve injury. Thus, experimental and clinical data clearly point towards the advantage of early nerve repair and reconstruction of injuries. Following an appropriate diagnosis of a nerve injury, the nerve should be promptly repaired or reconstructed, and new rehabilitation strategies should early be initiated. Considering nerve transfers in the treatment arsenal can shorten the time of nerve reinnervation of muscle targets. Timing of nerve repair and reconstruction is crucial after nerve injury.

Nerve injuries of the upper extremity and hand

“…10,11 These injury-induced signals, occurring in different phases, make the neurons able to switch from transmission state to a regenerative state causing changed expressions of many genes involved in survival or death of the neuron as well as in regrowth of the axons. 12-14 …”

“…16,17 Thus, a nerve repair or reconstruction procedure should be done promptly due to the fact that Schwann cells have ‘a best before date’ after a nerve injury. 10,18,19 …”

Serial assessment of functional recovery following nerve injury using implantable thin‐film wireless nerve stimulators

“…Increased understanding of the time course of nerve injury and nerve regeneration may offer a unique opportunity to improve clinical outcomes following peripheral nerve repair . Comprehensive understanding of the time course of nerve injury, degeneration of distal axons, and functional status of terminal end organs predicts the maximal degree of functional recovery expected following surgical repair . Further examination of the time course of nerve regeneration using various nerve grafting and repair methods may provide critical insight into the expected time course and terminal capacity for functional recovery .…”

Nerve Transfers in the Treatment of Peripheral Nerve Injuries

“…The growth speed of the regenerating axons is ~1 mm/day [2]. The time needed for the regeneration will be proportional the distance between the injury site and the muscle endplates [3,4]. Proximal limb peripheral nerve injuries pose severe difficulties to a successful re-innervation because of the long distance regenerating axons have to cover [3], taking up to 24 months to reach hands or feet [2,5,6], often finding them atrophied and substituted by fat and fibrous tissue [7][8][9].…”

“…An adequate post-operative rehabilitation is a vital element in the final outcome and relies on cerebral plasticity in which neurons are assigned to new tasks [4,48].…”