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Nerve Grafting and Neurorraphy

last modified on: Mon, 04/01/2024 - 09:22

return to: Facial Paralysis (surgery for facial nerve paralysis weakness)

Nerve Grafting for Facial Paralysis (Cross Face Nerve Grafting)

Salivary Gland Surgery Protocols

Note: last updated before 2013

GENERAL CONSIDERATIONS

  1. Indications
    1. Segmental loss of either a sensory or motor nerve is a potential indication for nerve grafting and neurorrhaphy.
    2. The benefits of a functional nerve graft versus other methods of facial reanimation are evident.
    3. It is now recognized that insensibility in large regions of the oral cavity and pharynx may present a significant functional deficit that is not immediately apparent in the evaluation of a post-ablative reconstruction result in which mandibular continuity has been restored and mucosal lining replaced. Sensory innervation of free tissue transfer flaps in the oral cavity using site-specific recipient nerves does result in greater levels of sensibility than passive ingrowth of surrounding sensory nerves.
  2. Contraindications
    1. There are few contraindications to attempted innervation or nerve grafting in the face of an existing defect.
    2. Planned postoperative radiation should not be viewed as a contraindication to nerve grafting or the use of a sensate flap. There may be some decrement in sensory or motor result; however, the results are generally acknowledged as superior to not using a graft.
    3. The recipient site nerve margins should be evaluated with frozen section in oncologic cases prior to grafting.
  3. Pertinent Anatomy
    1. Neurorrhaphy in head and neck surgery is now most commonly performed during nerve graft replacement of an injured or resected nerve and during neural anastomosis of a sensate or functional free tissue flap.
    2. Potential nerve graft donor sites for use in the head and neck include the sural, medial or lateral antebrachial cutaneous, great auricular, and lateral femoral cutaneous nerves. The sural nerve and superficial branch of the radial nerve may be harvested as vascular nerve grafts in conjunction with the fibula or radial forearm free flaps.
    3. Peripheral nerves consist of an investing layer, the epineurium. Within the epineurium groups of axons travel within fascicles. Each fascicle is invested with perineurium. Considerable research has been undertaken to develop the optimal method of coapting two nerve ends. Methods including epineural and fascicular suturing, tissue adhesives, laser coaptation, and tubularization have been proposed.
    4. In general, the current gold standard for nerve repair remains the epineural repair using enough 9-0 or 10-0 monofilament sutures to hold the nerve ends in stable apposition. In cases of traumatic nerve injury, repair should be undertaken as soon as possible. There is no practical advantage to waiting three weeks following injury.

PREOPERATIVE PREPARATION

  1. Evaluation
    1. The intended graft nerve should be selected based upon suitability for the anticipated defect. The great auricular nerve has limited length, and the branching pattern is often not favorable if several distal branches are required.
    2. The medial antebrachial cutaneous nerve and sural nerve both have long segments available and favorable branching patterns for anastomosis to more than one distal facial nerve branch if required.
    3. The use of steroids (systemic or local) has not been shown to definitively improve function following nerve graft. We do, however, use a dose of Decadron prior to surgery (8 to 10 mg), and two subsequent doses at 8 and 16 hours postoperatively. This regimen is used primarily to decrease postoperative edema.
  2. Potential Complications
    1. Harvest of a nerve graft will always create a sensory deficit at the donor site, and patients should be aware of this.
    2. The degree of motor or sensory recovery with any nerve graft depends on a large variety of factors. Patients should be aware of this, and that despite a technically well-done procedure, the results may be unsatisfying.
    3. Patients should be warned about potential painful neuroma formation with harvest of a nerve graft.

NURSING CONSIDERATIONS

  1. Room Setup
    1. See Basic Soft Tissue Room Setup
    2. Microscope with a 250 lens (loupe magnification may be preferred)
  2. Instrumentation and Equipment
    1. Microsurgery Instrument Tray, Otolaryngology
    2. Bipolar Forceps Trays
    3. Minor Instrument Tray, Otolaryngology
    4. Halsted microline artery forceps, curved
    5. Cautery electrode needle tip, guarded
    6. Nerve stimulator control unit and instrument
    7. Nerve harvesting equipment (tendon stripper) if harvesting sural nerve
  3. Medications (specific to nursing)
    1. Antibiotic ointment
    2. 1% lidocaine with 1:100,000 epinephrine
    3. Epinephrine 1:100,000
  4. Prep and Drape
    1. Standard prep, 10% providone iodine
      1. The nerve donor site should be prepped widely to prevent struggling to get additional length on the graft during harvest.
      2. If the sural nerve is to be harvested, the entire lower leg and foot are prepped.
      3. If the medial antebrachial cutaneous nerve is to be harvested, the entire arm is prepped. This wide prep significantly facilitates harvest, particularly if a branching pattern is identified, which must be dissected more distally than anticipated.
    2. Drape
      1. Head drape
      2. Towels to square off around the incision below the clavicle and donor nerve harvest site
      3. Split sheet
  5. Drains and Dressings
    1. Antibiotic ointment to suture line

ANESTHESIA CONSIDERATIONS

  1. Specific
    1. Position of the patient should permit access to both the recipient site and donor nerve harvest site.
    2. If motor nerve stimulation will be used to identify distal ends of a traumatized nerve, no paralysis should be used until after all such branches are identified.

OPERATIVE PROCEDURE

  1. Nerves should be harvested with the use of loupe magnification in order to minimize trauma to the nerve during harvest.
  2. A longitudinal incision in made over the more proximal portion of the nerve to be harvested and extended as needed. Stair-step transverse incisions should not be utilized in most cases as this requires that the nerve be harvested with considerably more manipulation and potential trauma.
  3. Nerve ends are cut with a new #15 scalpel or similar blade. Scissors are not used. A semisolid backstop upon which to cut the nerve may be useful, such as a sterile tongue blade. Nerve ends should be freshened prior to inset with a new clean cut done on a back table.
  4. An epineurial repair using a microscope or loupes is performed with 9-0 or 10-0 sutures, depending on the size of the graft and recipient nerve. Apart from a clean transverse cut, we do not perform any special preparation of the graft or recipient nerve ends.
  5. Most neurorrhaphy require from 3 to 7 sutures. Just enough sutures should be placed to permit stable coaptation of the epineurium. If fascicles are protruding from between the nerve ends, the epineurium in these areas needs to be more closely reapproximated. If that is not possible, the neurorrhaphy should be taken down, the ends freshened, and the neurorrhaphy repeated.  The use of a small amount of tiseel to cover the neurorrhaphy can be used.
  6. The neurorrhaphy should be under no tension and should be situated such that it will not be subjected to tension when the patient begins to move postoperatively. The nerve graft or sensory donor nerve should be cut to the minimal length that allows a tension-free neurorrhaphy.
  7. When nerve grafting or sensory neurorrhaphy is being done in conjunction with a free tissue transfer, it should be done after the flap has been inset in order to minimize manipulation of the neurorrhaphy. In some cases, due to geometry considerations, this may not be possible. In these cases, great care must be taken to avoid tension on the neurorrhaphy during flap insetting or vascular pedicle positioning.

POSTOPERATIVE CARE

  1. Recovery of neural function will depend upon a number of factors. In the absence of postoperative radiation, with a relatively short donor nerve, sensory recovery of an innervated flap may begin in three months. Motor function following nerve grafting of the facial nerve may not demonstrate any recovery for greater than one year. Patients should be given realistic estimates regarding potential timelines for recovery of function.
  2. Systemic steroid use in nerve graft functional recovery has been suggested, but not definitively proved. We do not use systemic steroids apart from those used in the immediate perioperative period.

REFERENCES

Buehler MJ, Seaber AV, Urbaniak JR. The relationship of functional return to varying methods of nerve repair. J Reconstr Microsurg. 1990;6:61-69.

Haller JR, Shelton C. Medial antebrachial cutaneous nerve: a new donor graft for repair of facial nerve defects at the skull base. Laryngoscope. 1997;107:1048-1052.

Kapur K, Garrett N, Fischer E. Effects of oral anesthesia on food manipulation during mastication. Arch Oral Biol. 1990;36:397-403..

McNamara MJ, Garrett WE, Seaber AV, Goldner JL. Neurorrhaphy, nerve grafting, and neurotization: a functional comparison of nerve reconstruction techniques. J Hand Surg. 1987;12A:354-60.

Santamaria E, Wei FC, Chen IH, Chuang DCC. Sensation recovery on innervated radial forearm flap for hemiglossectomy reconstruction by using different recipient nerves. Plast Reconst Surg. 1999;103:450-457.

Terris DJ, Fee WE. Current issues in nerve repair. Arch Otolaryngol Head Neck Surg. 1993;119:725-731.

Urken ML. The restoration or preservation of sensation in the oral cavity following ablative surgery. Arch Otolaryngol Head Neck Surg. 1995;121:607-612.