Research & Current Literature
List compiled by Robin Lindsay, M.D.
Rivas, A., K. D. Boahene, et al. (2011). "A Model for Early Prediction of Facial Nerve Recovery After Vestibular Schwannoma Surgery." Otol Neurotol.
OBJECTIVE:: To identify early predictors of long-term facial nerve function after vestibular schwannoma resection. STUDY DESIGN:: Retrospective chart review. SETTING:: Tertiary referral center. PATIENTS:: Subjects with facial nerve weakness despite anatomic preservation of the nerve after removal of vestibular schwannoma. INTERVENTION:: Surgical resection of vestibular schwannoma. MAIN OUTCOME MEASURE:: Facial function after 1 postoperative year. Independent variables included patient demographics, presenting symptoms, tumor size and location, and serial postoperative function within the first year. RESULTS:: Among 281 patients with postoperative facial weakness, 81% improved to a House-Brackmann (HB) III or better (good outcome) after 12 months of recovery, whereas 12% remained HB IV or worse (poor outcome). For patients starting with HB V or VI function, recovery rate was the most reliable predictor of poor outcome after 1 year. The resulting predictive model using rate of functional improvement as the independent variable was found to anticipate poor outcome before 1 year in more than 50% of cases with 97% sensitivity and 97% specificity. Although associated with facial nerve outcome, tumor size, tumor vascularity, preoperative facial function, age at surgery, and ability to stimulate the nerve intraoperatively did not contribute significantly to the predictive model. CONCLUSION:: The rate of recovery within the first postoperative year serves as a useful early predictor of long-term facial nerve function. We present a novel predictive model using rate of recovery that can be used to select candidates for reanimation surgery sooner than the traditional waiting period of 1 year, potentially improving the outcome of this intervention.
Bendella, H., S. P. Pavlov, et al. (2011). "Non-invasive stimulation of the vibrissal pad improves recovery of whisking function after simultaneous lesion of the facial and infraorbital nerves in rats." Exp Brain Res.
We have recently shown that manual stimulation of target muscles promotes functional recovery after transection and surgical repair to pure motor nerves (facial: whisking and blink reflex; hypoglossal: tongue position). However, following facial nerve repair, manual stimulation is detrimental if sensory afferent input is eliminated by, e.g., infraorbital nerve extirpation. To further understand the interplay between sensory input and motor recovery, we performed simultaneous cut-and-suture lesions on both the facial and the infraorbital nerves and examined whether stimulation of the sensory afferents from the vibrissae by a forced use would improve motor recovery. The efficacy of 3 treatment paradigms was assessed: removal of the contralateral vibrissae to ensure a maximal use of the ipsilateral ones (vibrissal stimulation; Group 2), manual stimulation of the ipsilateral vibrissal muscles (Group 3), and vibrissal stimulation followed by manual stimulation (Group 4). Data were compared to controls which underwent surgery but did not receive any treatment (Group 1). Four months after surgery, all three treatments significantly improved the amplitude of vibrissal whisking to 30 degrees versus 11 degrees in the controls of Group 1. The three treatments also reduced the degree of polyneuronal innervation of target muscle
fibers to 37% versus 58% in Group 1. These findings indicate that forced vibrissal use and manual stimulation, either alone or sequentially, reduce target muscle polyinnervation and improve recovery of whisking function when both the sensory and the motor components of the trigemino-facial system regenerate.
Kowalski, T. J., W. L. Berth, et al. (2011). "Oral antibiotic treatment and long-term outcomes of Lyme facial nerve palsy." Infection.
PURPOSE: To study the long-term functional outcomes of patients with Lyme facial nerve palsy treated with oral antibiotics. METHODS: We conducted a retrospective double-cohort study involving patients with Lyme facial nerve palsy treated with oral antibiotics matched to three controls with early localized Lyme disease. Chart review was completed and an SF-36 health questionnaire and standardized symptom questionnaire administered. RESULTS: Lyme facial nerve palsy patients were treated with oral antibiotics for a median duration of 21 days (range 7-30 days). Only three patients underwent lumbar puncture and each demonstrated lymphocytic pleocytosis. Fourteen of 15 patients with Lyme facial nerve palsy completely regained nerve function. The long-term outcomes were similar between patients with Lyme facial nerve palsy and controls after a median follow-up duration of 4.6 years. Patients with Lyme facial nerve palsy had significantly higher reported rates of fatigue (60%) than controls (27%) (p = 0.019), but similar energy and vitality scores on the SF-36 questionnaire (55.0 vs. 58.4, p = 0.621). SF-36 social functioning domain scores were significantly lower in patients with Lyme facial nerve palsy (77.5) than in controls (88.6) (p = 0.044). There were no other significant differences noted between the two cohorts. CONCLUSIONS: For patients with Lyme facial nerve palsy in North America, treatment with oral doxycycline appears to be an effective therapeutic strategy.
Angelov, D. N. (2011). "Physical rehabilitation of paralysed facial muscles: functional and morphological correlates." Adv Anat Embryol Cell Biol 210: 1-140, preceding 141.
Using a combined morphofunctional approach, we recently found that polyinnervation of the neuromuscular junction (NMJ) is the critical factor for recovery of function after transection and suture of the facial nerve. Since polyinnervation is activity-dependent and can be manipulated, we tried to design a clinically feasible therapy by electrical stimulation or by soft tissue massage. First, electrical stimulation was applied to the transected facial nerve or to paralyzed facial muscles. Both procedures did not improve vibrissal motor performance (video-based motion analysis of whisking), failed to diminish polyinnervation, and even reduced the number of innervated NMJ to one-fifth of normal values. In contrast, gentle stroking of the paralyzed vibrissal muscles by hand resulted in full recovery of whisking. Manual stimulation depended on the intact sensory supply of the denervated muscle targets and was also effective after hypoglossal-facial anastomosis, after interpositional nerve grafting, when applied to the orbicularis oculi muscle and after transection and suture of the hypoglossal nerve. From these results, we conclude that manual stimulation is a noninvasive procedure with immediate potential for clinical rehabilitation following facial nerve reconstruction.
Vakharia, K. T., R. W. Lindsay, et al. (2011). "The effects of potential neuroprotective agents on rat facial function recovery following facial nerve injury." Otolaryngol Head Neck Surg 144(1): 53-59.
Objective. To evaluate whether a series of pharmacologic agents with potential neuroprotective effects accelerate and/or improve facial function recovery after facial nerve crush injury. Study Design. Randomized animal study. Setting. Tertiary care facility. Methods. Eighty female Wistar-Hannover rats underwent head restraint implantation and daily conditioning. Animals then underwent unilateral crush injury to the main trunk of the facial nerve and were randomized to receive treatment with atorvastatin (n = 10), sildenafil (n = 10), darbepoetin (n = 20), or a corresponding control agent (n = 40). The return of whisking function was tracked throughout the recovery period. Results. All rats initiated the return of whisking function from nerve crush by day 12. Darbepoetin-treated rats (n = 20) showed significantly improved whisking amplitude and velocity across the recovery period, with several days of significant pairwise differences vs comparable control rats (n = 16) across the first 2 weeks of whisking function return. In contrast, rats treated with sildenafil (n = 10) and atorvastatin (n = 10) did not show significant improvement in whisking function recovery after facial nerve crush compared to controls. By week 8, all darbepoetin-treated animals and comparable nerve crush control animals fully recovered whisking function and were statistically indistinguishable. Conclusion. Among the 3 potentially neuroprotective agents evaluated, only darbepoetin administration resulted in accelerated recovery of whisking parameters after facial nerve crush injury. Further efforts to define the mechanism of action and translate these findings to the use of darbepoetin in the care of patients with traumatic facial paralysis are needed.
Biglioli, F., A. Frigerio, et al. (2011). "Masseteric-facial nerve anastomosis for early facial reanimation." J Craniomaxillofac Surg.
OBJECTIVE: Early repair of facial nerve paralysis when cortical neural input cannot be provided by the facial nerve nucleus, is generally accomplished anastomozing the extracranial stump of the facial nerve to a motor donor nerve. That is generally the hypoglossus, which carries a variable degree of morbidity. The present work aims to demonstrate the effectiveness of the masseteric nerve as donor for early facial reanimation, with the advantage that harvesting is associated with negligible morbidity. METHODS: Between October 2007 and August 2009, 7 patients (2 males, 5 women) with unilateral facial paralysis underwent a masseter-facial nerves anastomosis with an interpositional nerve graft of the great auricular nerve. The interval between the onset of paralysis and surgery ranged from 8 to 48 months (mean 19.2 months). All patients included in the study had signs of facial mimetic muscle fibrillations on electromyography. The degree of preoperative facial nerve dysfunction was grade VI following the House-Brackmann scale for all patients. RESULTS: At the time of the study, all the patients with a minimum follow-up time of 12 months after the onset of mimetic function had recovered facial animation. Facial muscles showed signs of recovery within 2-9 months, mean 4.8 months, with the restoration of facial symmetry at rest. Facial movements appeared while the patients activated their chewing musculature. Morbidity related to this intervention is only the loss of sensitivity of earlobe and preauricular region. CONCLUSION: The present technique seems to be a valid alternative to classical hypoglossal-facial nerve anastomosis because of similar facial nerve recovery and lower morbidity.
Osinga, R., H. J. Buncke, et al. (2011). "Subdivision of the sural nerve: Step towards individual facial reanimation." J Plast Surg Hand Surg 45(1): 3-7.
Abstract Long term facial paralysis is a serious affliction and upsetting for the patient. Dynamic facial reanimation has become the treatment of choice. Various techniques that use different donor muscles have been developed since the first functional muscle transplant for facial paralysis more than 30 years ago. The concept of using a single muscle was refined into the use of dividable muscle slips such as serratus muscle or separate muscular subunits to avoid the resulting mass movements. Because the results are still not satisfactory, efforts were put into also dividing the donor nerve transplant into corresponding subunits to create a continuous line of individual action. Twenty human cadaveric sural nerves were successfully dissected into three completely separate subunits, transecting the interfascicular bridges. This anatomical study gives the potential to allow an independent triple innervation of three separate serratus anterior muscle slips, so decreasing further the mass movement after facial reanimation.
Seitz, M., M. Grosheva, et al. (2011). "Poor functional recovery and muscle polyinnervation after facial nerve injury in fibroblast growth factor-2(-/-) mice can be improved by manual stimulation of denervated vibrissal muscles." Neuroscience.
Functional recovery following facial nerve injury is poor. Adjacent neuromuscular junctions (NMJs) are "bridged" by terminal Schwann cells and numerous regenerating axonal sprouts. We have recently shown that manual stimulation (MS) restores whisking function and reduces polyinnervation of NMJs. Furthermore, MS requires both insulin-like growth factor-1 (IGF-1) and brain-derived neurotrophic factor (BDNF). Here, we investigated whether fibroblast growth factor-2 (FGF-2) was also required for the beneficial effects of MS. Following transection and suture of the facial nerve (facial-facial anastomisis, FFA) in homozygous mice lacking FGF-2 (FGF-2(-/-)), vibrissal motor performance and the percentage of poly-innervated NMJ were quantified. In intact FGF-2(-/-) mice and their wildtype (WT) counterparts, there were no differences in amplitude of vibrissal whisking (about 50 degrees ) or in the percentage of polyinnervated NMJ (0%). After 2 months FFA and handling alone (i.e. no MS), the amplitude of vibrissal whisking in WT-mice decreased to 22+/-3 degrees . In the FGF-2(-/-) mice, the amplitude was reduced further to 15+/-4 degrees , that is, function was significantly poorer. Functional deficits were mirrored by increased polyinnervation of NMJ in WT mice (40.33+/-2.16%) with polyinnervation being increased further in FGF-2(-/-) mice (50.33+/-4.33%). However, regardless of the genotype, MS increased vibrissal whisking amplitude (WT: 33.9 degrees +/-7.7; FGF-2(-/-): 33.4 degrees +/-8.1) and concomitantly reduced polyinnervation (WT: 33.9%+/-7.7; FGF-2(-/-): 33.4%+/-8.1) to a similar extent. We conclude that, whereas lack of FGF-2 leads to poor functional recovery and target reinnervation, MS can nevertheless confer some functional benefit in its absence.
Kanerva, M., L. Jonsson, et al. (2011). "Sunnybrook and house-brackmann systems in 5397 facial gradings." Otolaryngol Head Neck Surg 144(4): 570-574.
Objectives. To study the correlation between Sunnybrook and House-Brackmann facial grading systems at different time points during the course of peripheral facial palsy. Study Design. Prospective multicenter trial. Setting. Seventeen otorhinolaryngological centers. Subjects and Methods. Data are part of the Scandinavian Bell's palsy study. The facial function of 1920 patients with peripheral facial palsy was assessed 5397 times with both Sunnybrook and House-Brackmann (H-B) facial grading systems. Grading was done at initial visit, at days 11 to 17 of palsy onset, and at 1 month, 2 months, 3 months, 6 months, and 12 months. Statistical evaluation was by Spearman correlation coefficient and box plot analysis. Results. Spearman correlation coefficient varied from -0.81 to -0.96, with the weakest correlation found at initial visit. Box plot analysis for all assessments revealed that Sunnybrook scores were widely spread over different H-B grades. With 50% of the results closest to the median, Sunnybrook composite scores varied in H-B grades as follows: H-B I, 100; H-B II, 71 to 90; H-B III, 43 to 62; H-B IV, 26 to 43; H-B V, 13 to 25; and H-B VI, 5 to 14. Conclusion. Gradings correlated better in follow-up assessments than at initial visit. As shown by the wide overlap of the grading results, subjective grading systems are only approximate. However, a conversion table for Sunnybrook and H-B gradings was obtained and is included in the article. It can be used for further development of facial grading systems.