Functional Outcomes of Multiple Sural Nerve Grafts for Facial Nerve Defects after Tumor-Ablative Surgery

Abstract

Background: Functional restoration of the facial expression is necessary after facial nerve resection to treat head and neck tumors. This study was conducted to evaluate the functional outcomes of patients who underwent facial nerve cable grafting immediately after tumor resection.

Methods: Patients who underwent cable grafting from April 2007 to August 2011 were reviewed, in which a harvested branch of the sural nerve was grafted onto each facial nerve division. Twelve patients underwent facial nerve cable grafting after radical parotidectomy, total parotidectomy, or schwannoma resection, and the functional facial expression of each patient was evaluated using the Facial Nerve Grading Scale 2.0. The results were analyzed according to patient age, follow-up duration, and the use of postoperative radiation therapy.

Results: Among the 12 patients who were evaluated, the mean follow-up duration was 21.8 months, the mean age at the time of surgery was 42.8 years, and the mean facial expression score was 14.6 points, indicating moderate dysfunction. Facial expression scores were not influenced by age at the time of surgery, follow-up duration, or the use of postoperative radiation therapy.

Conclusions: The results of this study indicate that facial nerve cable grafting using the sural nerve can restore facial expression. Although patients were provided with appropriate treatment, the survival rate for salivary gland cancer was poor. We conclude that immediate facial nerve reconstruction is a worthwhile procedure that improves quality of life by allowing the recovery of facial expression, even in patients who are older or may require radiation therapy.

Keywords: Age groups; Facial nerve; Radiotherapy; Sural nerve; Surgery.

Fig. 1. Figures illustrating a cable graft procedure

(A) A facial nerve defect was noted after tumor resection (black and white arrows), and an adequate length of the sural nerve was harvested in order to serve as a cable connecting the proximal and distal facial nerve stumps. Cutaneous branches accompanied the sural nerve trunk, imitating the arborescent pattern of facial nerve branches. (B) The harvested nerve was then divided into two segments, with one corresponding to the temporofacial division of the facial nerve and the other corresponding to the cervicofacial division of the facial nerve. The superior and inferior halves of the proximal facial nerve trunk were anastomosed with two segments of the sural nerve stumps. If additional sural nerve endings were needed for distal facial nerve branches, the nerve was meticulously split, preserving the fascicles. Each nerve ending was anastomosed using a perineural technique under microscopic magnification.

Fig. 2. Average facial expression scores

(A) The average overall score was 14.7 (grade III), indicating moderate dysfunction. (B) The regional scores were 5.1 for the forehead and brow area (trace movement), 3.4 for the periorbital area (good movement, 50%-75% of normal movement), and 2.8 for both the nasolabial fold (NLF) and perioral areas (slight weakness, >75% of normal movement). The average synkinesis score was 0.58.

Fig. 3. Outcomes depending on the subgrouping of patients

Patients were evaluated according to their age at the time of surgery, the use of postoperative radiotherapy, and follow-up duration. The average facial expression score was 16.4 in patients older than 50 years vs. 13.4 in patients younger than 50 years, 14.4 in patients who underwent RTx vs. 15.0 in those did not, and 15.3 for patients who underwent more than 18 months of follow-up vs. 14 in those who underwent less than 18 months of follow-up. These differences were not significant. FU, follow-up; RTx, radiation therapy.

Fig. 4. Case I: assessment of facial expression

A 23-year-old female patient underwent radical parotidectomy for mucoepidermoid carcinoma of the right parotid gland (stage II), with concomitant facial nerve cable grafting; furthermore, she underwent radiation therapy (5,750 cGy). Photos of (A) the resting state and (B-E) facial expressions were taken nine months after surgery. The photos demonstrated that (C) eye squeezing and movements of (D) the nasolabial fold and (E) the oral commissure were fluent; however (B) forehead wrinkling was limited, and a slight degree of synkinesis was present. The regional Facial Nerve Grading Scale 2.0 score for (B) forehead and brow movement (5) was worse than the scores for (C) eye squeezing (2) and the movements of (D) the nasolabial folds (2) and (E) the oral commissure (2). The synkinesis score was 1, resulting in a total score of 12 (grade III).

Fig. 5. Case II: assessment of facial expression

A 54-year-old female patient underwent total parotidectomy and supraomohyoid lymph node dissection for adenocarcinoma of the right parotid gland (stage III) with concomitant facial nerve cable grafting. Pictures of (A) the resting state and (B-E) facial expressions were taken 20 months after surgery. (C) The outcomes showed eye-squeezing movements, although lagophthalmos was noted. (B) Furthermore, forehead wrinkling was limited. (A) The nasolabial folds and oral commissure revealed resting symmetry, (D, E) but obvious weakness was noted while forming facial expressions. The Regional Facial Nerve Grading Scale 2.0 scores for (B) the brow (4) and (C) eye squeezing (4) were worse than the scores for (D) the nasolabial folds (3) and (E) the oral commissure (3). The synkinesis score was 1, leading to a total score of 15 (grade IV).