Median nerve epineural and group fascicular nerve repair

Indications

• Any deficits attributable to the median nerve with an associated laceration or injury along the course of the nerve, high-energy injuries associated with blunt trauma and no appreciable median nerve recovery on examination, and prior median nerve repairs with no appreciable recovery on examination after 6 months.

• Simultaneous flap coverage should be considered if there is lack of soft tissue over the nerve.

Clinical examination

• Carefully assess any areas for lacerations or other wounds.

• Assess median nerve sensory innervation along the radial and ulnar sides of the thumb, index, and middle fingers; the nerve also provides sensation to the radial side of the ring finger.

• Assess median nerve motor function via thumb palmar abduction and opposition.

• Palpate and percuss to identify an advancing Tinel sign or symptomatic neuromas.

• Because of the communicating branches between the median and ulnar nerve (i.e., Martin-Gruber and Riche-Cannieu), patients may have preserved motor function in the presence of an open injury.

Imaging

Electromyography and nerve conduction studies are useful to detect the presence or absence of sensory and/or motor deficits, as well as denervation/reinnervation based on increased latencies, decreased amplitudes, and/or the presence of fasciculations or fibrillations within the muscle upon needle insertion during this examination.

Surgical anatomy

• See Chapters 63 and 64 for pertinent anatomy of the nerve.

• The median nerve is a mixed sensory and motor nerve with distinct grouped fascicles. It is critical to identify and realign the fascicles when performing repair ( Figs. 62.1 and 62.2 ).

  
  

• See Chapter 60 for the list of potential donor nerves for the graft.

Positioning

• The operation should be performed under tourniquet control to visualize the injured nerve clearly, with the arm outstretched on the hand table.

• A nerve stimulator can be useful to identify an intact nerve in the scarred tissue.

• A microscope is used to perform a meticulous nerve repair.