Patient Selection

The ideal reanimation procedure in any patient with disruption of the facial nerve is reconstitution of the nerve by primary repair or by grafting to re-establish continuity between the facial nerve nucleus and facial musculature. The procedure should be done in a clean field as soon as possible after the injury. Factors affecting results include the condition of the nerve, the time after onset of paralysis, the presence of tumor in the nerve, and the adherence to microsurgical techniques of nerve repair. Ideally, the procedure should be done in the first 30 days; if not, and the results of repair are disappointing after 1 year.¹

Surgical Technique

After trimming the ends of the nerve to achieve a healthy nerve for anastomosis devoid of trauma, debris, or neoplasm, the surgeon must assess the need for a graft. A primary repair offers no advantage if the two nerves are under tension, and this can be assessed if the nerves stay in good approximation without sutures. The fewest number of sutures necessary to achieve stable coaptation of the nerve suffice. Intracranially, sutures may be limited technically to one or two 9-0 or 10-0 monofilament sutures; in the temporal bone, no suturing is required; and extracranially, two or three sutures are sufficient. Nerve repair is traditionally either by epineurial or by fascicular repair techniques, and studies have not supported superiority of one over the other. Likewise, reversing grafts and clipping nonessential branches have not provided advantages.¹

The use of graft is dictated by the deficit present. Most defects for the otologist can be accommodated by use of the greater auricular nerve. This branch of C-2 and C-3 is a good size match for the facial nerve, and provides two reliable branches for intraparotid use. The total length available is 7 cm. The nerve is generally close to a perpendicular line drawn at the midpoint of an imaginary line connecting the mastoid tip to the angle of the mandible. Patients should be advised of the sensory loss that accompanies this or any proposed nerve grafts that are selected for use.

The medial branchial cutaneous nerve is selected when the greater auricular is unavailable, is too short, or lacks the additional necessary branching pattern.² This graft is a sensory nerve of the arm, provides a good size match for the facial nerve, has a potential length of 20 cm, and usually has at least four branches. In comparison, the sural nerve, found behind the lateral malleolus in relation to the lesser saphenous vein, offers 35 cm in length, and an adequate branching pattern, but is generally larger in diameter than the facial nerve. We have successfully harvested the sural nerve using the minimally invasive endoscopic technique being employed for saphenous vein harvest.

We have been able to achieve a fair to superb facial nerve outcome in our nerve graft patients 80% of the time. Patients with paralysis caused by malignant tumors, older patients, and patients who had delay in repair tended to have poorer outcomes.³ Wax and Kaylie⁴ had no difference in facial nerve outcome, however, in patients who had a positive margin in the reconstructed nerve. In their series of 19 patients, they had a grade III or IV result in 50% of the patients in each group.

Patient Selection

Patients may have either a cross facial nerve graft or a hypoglossal nerve substitution if they are not candidates for a primary repair. Ideally, these procedures also should be performed in the first 30 days after injury. Results with a hypoglossal/facial jump graft are acceptable when performed 1 year after injury, and a full hypoglossal transfer can be performed 2 years after injury, although the synkinesis and tongue weakness must be considered and discussed extensively.⁵

Surgical Technique

Hypoglossal jump grafting is performed via the surgeon’s preferred standard parotid incision; either a facelift or modified Blair is acceptable. Standard landmarks of the tragal pointer and digastric muscle are used to locate the facial nerve. An additional useful landmark is the mastoid tip. The facial nerve generally is located in a superoinferior aspect at the midpoint of the surgeon’s finger when placed on the mastoid tip at the depth of the digastric muscle.

The facial nerve is isolated from this point out to the level of the first bifurcation with meticulous hemostasis. Transection of the nerve should be done without transecting the epineurium on the posterior aspect of the nerve. Preserving the epineurium at this point allows for ease of microscopically performed neurorrhaphy, preventing the retraction of the distal nerve into the parotid tissue.

The hypoglossal nerve is found in relation to the posterior aspect of the digastric muscle. Visualization of the nerve usually requires retraction of the digastric superiorly. The nerve always passes lateral to the carotid artery, and retrograde dissection from this point is sometimes helpful, especially in the presence of significant adipose tissue. Using the nerve just distal to the ansa cervicalis allows for better therapy to retrain the patient’s smile because only tongue motion fibers are redirected up to the facial nerve. A small Penrose drain can be passed behind the nerve at this location and tightened using a self-retaining retractor. This drain gently elevates the hypoglossal nerve into the field and avoids obscuring tissue fluid at the time of repair. This procedure is being discussed in greater detail in Chapter 62.

The cross-face anastomosis was originally described by Scaramella⁶ and modified over the years by many surgeons. It is most useful when powering a free muscle graft for recreating a smile. It has been of more limited usefulness when trying to reanimate the entire facial nerve from a branch or branches of the contralateral side, which is why my preference has been for the jump graft in most patients.

Patient Selection

Patients who may be candidates for temporalis muscle transposition include patients (1) who have absent or poor facial function, either with spontaneous recovery 2 years after the onset of paralysis or 2 years after nerve repair or nerve grafting; (2) who are not candidates for or refuse facial nerve repair or grafting or facial/hypoglossal nerve grafting; (3) who have neurofibromatosis, ipsilateral CN X paralysis, or another condition that is a contraindication to facial/hypoglossal nerve grafting; and (4) who have undeveloped facial nerves or facial musculature, such as may occur with Möbius syndrome.^3,4 The procedure has also been recommended to give reasonable function and symmetry while awaiting the results of a nerve graft to occur, and to augment the results of facial nerve repair or grafting.⁷

Patient Evaluation

Systematic assessment of facial function in a patient who has elected to undergo temporalis muscle transposition includes evaluation of all areas of the face at rest and with smiling. The positions of the nasal alae, depths of nasolabial creases, and nasal airway structures are evaluated. The appearance of nasolabial structures should be considered in the planning for temporal muscle transposition. Airway structures are evaluated because nasal valve collapse may have occurred, and if a nasal septal deformity is also present, nasal obstruction could result. Nasal obstruction may indicate the need for a nasoseptoplasty procedure to be performed at the time of temporalis muscle transposition.