When a nerve is cut completely, the elastic tissue within the nerve would cause the two cut ends to retract from each other, thus creating a nerve gap. If the cut is clean and there is no undue delay to surgery, a primary repair of the nerve is possible with mobilisation of the cut ends.

If there has been substance loss due to trauma or necessary debridement to healthy tissue ends, a nerve defect is then encountered. In these situations, attempting to restore continuity of the nerve directly may lead to too much tension at the repair site. Clinical and experimental studies have confirmed the deleterious effects of undue tension at a nerve repair site, ultimately leading to poor outcome. As a result, a conduit or a graft is necessary to bridge the defect.

Options of Nerve Graft/Conduit

 Autologous (from the patient)  Off-the-shelf
  • Nerve autograft
    • sural nerve
    • PIN
    • MABC
  • Vein +/- muscle
  • Nerve conduits
    • Type I collagen
    • Caprolactone
    • Polyglycolic acid (PGA)
    • Porcine submucosal extracellular matrix
  • Processed nerve allograft

Nerve autograft remains the gold standard in grafting. However it is associated with donor site morbididty, which can be avoided with off-the-shelf options. The choice of a graft/conduit is dependent upon:

  • The length of nerve defect/gap
  • The type of nerve injured (sensory, motor or mixed)
  • The size/diameter of the nerve injured
  • Patient’s acceptability to off-the-shelf options such as allograft (cadaveric nerve) and animal products (bovine type I collagen and porcine matrix)
  • Costs

There are some prerequisites to performing a successful nerve grafting:

  1. Skeletal stability
  2. Healthy tissue bed
  3. Healthy nerve ends
  4. Tension-free neurorrhaphy
  5. Adequate soft tissue coverage
  6. Appropriate timing 

Key Message

  • A nerve defect could be the result of:
    • Traumatic loss
    • Debridement of the damaged nerve ends
    • Delay in performing repair with consequent retraction
  • A tight repair leads to a poor result.


Book your consultation today