Abstract
Purpose
Reanimation of facial paralysis is a complex problem with multiple treatment options. One option is hypoglossal-facial nerve grafting, which can be performed in the immediate postoperative period after nerve transection, or in a delayed setting after skull base surgery when the nerve is anatomically intact but function is poor. The purpose of this study is to investigate the effect of timing of hypoglossal-facial grafting on functional outcome.
Materials and methods
A retrospective case series from a single tertiary otologic referral center was performed identifying 60 patients with facial nerve injury following cerebellopontine angle tumor extirpation. Patients underwent hypoglossal-facial nerve anastomosis following facial nerve injury. Facial nerve function was measured using the House–Brackmann facial nerve grading system at a median follow-up interval of 18 months. Multivariate logistic regression analysis was used determine how time to hypoglossal-facial nerve grafting affected odds of achieving House–Brackmann grade of ≤ 3.
Results
Patients who underwent acute hypoglossal-facial anastomotic repair (0–14 days from injury) were more likely to achieve House–Brackmann grade ≤ 3 compared to those that had delayed repair (OR 4.97, 95% CI 1.5–16.9, p = 0.01).
Conclusions
Early hypoglossal-facial anastomotic repair after acute facial nerve injury is associated with better long-term facial function outcomes and should be considered in the management algorithm.
1
Introduction
Facial nerve paralysis is a well-recognized complication of skull base surgery, with documented rates of transection as high as 6% . It continues to represent a significant operative morbidity despite improved surgical technique and the routine use of nerve monitors. Consequences of this injury can be devastating and include exposure keratosis and blindness, disfigurement, poor nasal airflow, oral incompetence, synkinesis, and psychological stress .
Management largely depends on nerve integrity. An injured, but intact facial nerve presents a unique prognostic dilemma, as it is difficult to predict the ultimate degree of recovery. In contrast, a transected nerve results in predictably severe sequelae. Several types of procedures have been devised in an attempt to rehabilitate patients with this complication . One approach, first described by Korte in 1904 , is transposition of cranial nerve XII (hypoglossal) to the distal stump of VII (facial) (i.e., XII–VII transposition). Its primary indication is situations when the proximal portion of VII is inaccessible or non-functional. A second indication is complete paralysis persisting greater than one year . In both instances, the goal is to provide alternate cortical input to the mimetic musculature.
Previous investigations reported that nearly all patients treated with hypoglossal-facial nerve anastomosis have some functional improvement, and that 65% achieve a House–Brackmann 3 or better . However, controversy surrounds whether timing of repair affects the ultimate degree of facial mimetic recovery. The challenge exists to identify patients that will not spontaneously recover nerve function and would benefit from earlier intervention. One report failed to show an outcome association related to the interval between acoustic neuroma surgery (i.e., injury) and rehabilitation with XII–VII transposition . In contrast, other studies suggest that delayed repair (greater than 1–2 years from injury) is associated with less favorable outcomes . The purpose of this retrospective case series is to investigate whether early rehabilitation with XII–VII transposition (0–14 days from injury) resulted in better outcomes (House–Brackmann (HB) grade ≤ 3) than patients treated in a more delayed manner.
2
Materials and methods
The study was performed in accordance with the Declaration of Helsinki, Good Clinical Practice, and approved by the Vanderbilt Institutional Review Board (IRB# 120693).
2.1
Subject selection
All cerebellopontine angle (CPA) surgeries for presumed vestibular schwannoma (VS) performed between 1979 and 2007 were identified. Medical records were reviewed to identify patients who: (i) underwent resection of a histopathologically confirmed CPA vestibular schwannoma, (ii) had postoperative facial paresis (HB 4 or greater) either by nerve transection or poor function in the setting of anatomically intact nerve, (iii) underwent postoperative reanimation surgery by XII–VII nerve anastomosis, and (iv) had follow-up data available postoperatively with last documented facial nerve function being used in the final analysis. Patients with known intraoperative transection of the nerve underwent early reanimation, while those with anatomically intact nerves after resection but poor function underwent delayed nerve transfer. Patients with pathology other than vestibular schwannoma (meningioma, astrocytoma, facial schwannoma) were excluded from analysis.
2.2
Variables collected
Patient characteristics (age, gender, tobacco use, comorbid conditions [e.g., diabetes mellitus, peripheral vascular disease, hypertension, hypercholesterolemia]), initial data on the surgical resection of skull base tumor (extent of resection, nerve status at time of surgery) timing of XII–VII surgery, and outcomes were extracted from medical records. The primary outcome was facial nerve function one year after XII–VII surgery, which was graded using the House–Brackmann (HB) classification . Function was evaluated and recorded preoperatively, immediately postoperatively, and at each subsequent follow-up clinic visit. A successful outcome was defined a priori as HB ≤ 3, as patients with HB ≤ 3 have symmetry at rest and are able to completely close the eye.
2.3
Statistical analysis
Analyses were performed to determine whether timing of XII–VII transposition was associated with ultimate facial nerve functional outcome. The dependent variable was facial nerve function one year following XII–VII transposition defined by HB grade. For analysis, HB grades were dichotomized into ≤ 3 (i.e., success) or > 3. Multivariate logistic regression analysis was used to estimate adjusted odds (95% CI) of HB ≤ 3 at follow-up. Parametric and non-parametric tests were used as appropriate and all analyses performed using STATA 12MP (College Station, TX).
2
Materials and methods
The study was performed in accordance with the Declaration of Helsinki, Good Clinical Practice, and approved by the Vanderbilt Institutional Review Board (IRB# 120693).
2.1
Subject selection
All cerebellopontine angle (CPA) surgeries for presumed vestibular schwannoma (VS) performed between 1979 and 2007 were identified. Medical records were reviewed to identify patients who: (i) underwent resection of a histopathologically confirmed CPA vestibular schwannoma, (ii) had postoperative facial paresis (HB 4 or greater) either by nerve transection or poor function in the setting of anatomically intact nerve, (iii) underwent postoperative reanimation surgery by XII–VII nerve anastomosis, and (iv) had follow-up data available postoperatively with last documented facial nerve function being used in the final analysis. Patients with known intraoperative transection of the nerve underwent early reanimation, while those with anatomically intact nerves after resection but poor function underwent delayed nerve transfer. Patients with pathology other than vestibular schwannoma (meningioma, astrocytoma, facial schwannoma) were excluded from analysis.
2.2
Variables collected
Patient characteristics (age, gender, tobacco use, comorbid conditions [e.g., diabetes mellitus, peripheral vascular disease, hypertension, hypercholesterolemia]), initial data on the surgical resection of skull base tumor (extent of resection, nerve status at time of surgery) timing of XII–VII surgery, and outcomes were extracted from medical records. The primary outcome was facial nerve function one year after XII–VII surgery, which was graded using the House–Brackmann (HB) classification . Function was evaluated and recorded preoperatively, immediately postoperatively, and at each subsequent follow-up clinic visit. A successful outcome was defined a priori as HB ≤ 3, as patients with HB ≤ 3 have symmetry at rest and are able to completely close the eye.
2.3
Statistical analysis
Analyses were performed to determine whether timing of XII–VII transposition was associated with ultimate facial nerve functional outcome. The dependent variable was facial nerve function one year following XII–VII transposition defined by HB grade. For analysis, HB grades were dichotomized into ≤ 3 (i.e., success) or > 3. Multivariate logistic regression analysis was used to estimate adjusted odds (95% CI) of HB ≤ 3 at follow-up. Parametric and non-parametric tests were used as appropriate and all analyses performed using STATA 12MP (College Station, TX).
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