Research & Current Literature
List compiled by Robin Lindsay, M.D.
Rozen, S. M. (2011). "Discussion: treatment of facial paralysis: dynamic reanimation of spontaneous facial expression-apropos of 655 patients." Plast Reconstr Surg 128(6): 704e-706e.
Barr, J. S., K. A. Katz, et al. (2011). "Surgical management of facial nerve paralysis in the pediatric population." J Pediatr Surg 46(11): 2168-2176.
BACKGROUND: In the pediatric patient population, both the pathology and the surgical managements of seventh cranial nerve palsy are complicated by the small size of the patients. Adding to the technical difficulty is the relative infrequency of the diagnosis, thus making it harder to become proficient in the management of the condition. The magnitude of the functional and aesthetic deficits these children manifest is significantly troubling to both the patient and the parents, which makes immediate attention, treatment, and functional restoration essential. METHODS: A literature search using PubMed (http://www.pubmed.org) was undertaken to identify the current state of surgical management of pediatric facial paralysis. RESULTS: Although a multitude of techniques have been used, the ideal reconstructive procedure that addresses all of the functional and cosmetic needs of these children has yet to be described. Certainly, future research and innovative thinking will yield progressively better techniques that may, one day, emulate the native facial musculature with remarkable precision. CONCLUSION: The necessity for surgical intervention in children with facial nerve paralysis differs depending on many factors including the acute/chronic nature of the defect as well as the extent of functional and cosmetic damage. In this article, we review the surgical procedures that have been used to treat pediatric facial nerve paralysis and provide therapeutic facial reanimation.
Vanderwerf, F., D. Reits, et al. (2011). "Long-Term Effect of Prednisolone on Functional Blink Recovery after Transient Peripheral Facial Motor Paralysis." Otolaryngol Head Neck Surg.
Objective. To determine the functional recovery in patients with severe transient peripheral facial motor paralysis (Bell palsy).Study Design. Prospective controlled trial.Setting. Academic medical center.Subjects and Methods. Blink recovery was studied in 2 groups of severely affected Bell palsy patients during a follow-up period of 84 weeks. The patients in one group received prednisolone within the first week after the onset of symptoms. No medication was given to the other group. A control group of healthy subjects was also included. Simultaneous orbicularis oculi muscle activity and eyelid kinematics were recorded by surface electromyographic (EMG) recording and eyelid search coils, respectively.Results. At the beginning of the paralysis, very little integrated orbicularis oculi muscle activity and eyelid movement was measured at the palsied side of the face. Thirteen weeks later, the integrated orbicularis oculi EMG and functional blink recovery gradually improved until 39 weeks. Beyond, only the integrated orbicularis oculi EMG slightly increased. At 84 weeks, the integrated orbicularis oculi EMG was significantly larger in the prednisolone group compared with the control group. The integrated EMG of the nonmedicated group recovered to normal values. Curiously enough, the functional blink recovery at the palsied side remained reduced to 64% compared with the healthy controls in the prednisolone-treated group and to 36% in the nonmedicated group.Conclusion. The authors demonstrate that prednisolone significantly increased the orbicularis oculi muscle activity and significantly improved functional blink recovery in severely affected Bell palsy patients. However, the increase of muscle activity was insufficient to restore functional blinking to normal values.
Saito, H. (2011). "A simple objective evaluation and grading for facial paralysis outcomes." Acta Otolaryngol.
Abstract Conclusion: A simple measuring box to determine lip-shift angle and eye-width narrowing offered simultaneous and objective data on outcome dysfunction. The method is as easy as visual approaches. The method is objective and as easy as visual access. It is practical for routine clinical use in any clinic. Objectives: The outcome dysfunction after facial paralysis is commonly evaluated by subjective visual access. This paper introduces a new method for simple objective evaluation and grading with documentation of lip-shift and eye-width changes. Methods: Thirty adult controls were used to determine standard deviations (SDs) for angular shift of the lip at rest and eye-width narrowing at maximum lip protrusion. Thirty patients with facial paralysis more than 6 months after onset were studied for outcomes in terms of synkinesis, contracture, and lip deviation to the healthy side. Abnormalities were read with a simple measuring box. Results: Among the controls, mean lip shift at rest and its SD were 0 degrees and 1.2. Mean eye narrowing at maximum lip protrusion effort and its SD were -0.6 mm and 1.6. This paper proposes a new grading system that relies simply on the sum of evaluating items exceeding 2 SDs, or residual lip deviation to the healthy side.
Burgette, R. C., B. J. Benscoter, et al. (2011). "A Rat Model for Intracranial Facial Nerve Crush Injuries." Otolaryngol Head Neck Surg.
Objective. (1) Explain the need for an animal model to study intracranial injuries to the facial nerve. (2) Describe various techniques attempted to identify and crush the intracranial segment of the facial nerve in a rat model. (3) Describe in detail a successful rat model of intracranial facial nerve crush injury.Study Design. Randomized controlled animal study.Setting. Animal laboratory.Subjects and Methods. Multiple attempts at surgical approaches to the cerebellopontine angle were attempted on cadaveric rats. Once a successful approach was derived, this was used on 19 live rats under anesthesia. Fourteen rats had a 1-minute facial nerve crush performed, and 5 had a sham surgery with complete surgical exposure of the facial nerve but no crush. Rats were followed for a 12-week duration evaluating immediate postoperative facial nerve function, complications, and survival.Results. All 14 (100%) rats that underwent surgery with crush injury had complete facial paralysis postoperatively. Complete facial paralysis was defined as loss of eye-blink reflex, flat vibrissae, and lack of vibrissae movement. The 5 sham surgery rats had complete facial function postoperatively. Surgery was performed by 2 separate surgeons with no difference in outcome between the 2. Complications occurred in only 1 animal (1/19, 5.3%), which was a corneal abrasion requiring sacrifice.Conclusion. Our group describes a consistent method for performing an intracranial crush injury in the rat. This new model and its applications in translational facial nerve research are promising, particularly with tumors or lesions at the cerebellopontine angle.
Casanova-Molla, J., L. Leon, et al. (2011). "Reinnervation by the contralateral facial nerve in patients with peripheral facial palsy." Muscle Nerve 44(6): 923-929.
Introduction: Reinnervation activity is triggered after complete unilateral peripheral facial palsy (PFP). Methods: In 27 patients with PFP we recorded electromyographic activity with a concentric needle electrode inserted 1 cm lateral to the oral commissure of the affected side. We applied electrical stimuli to the unaffected (contralateral) facial nerve from the tragus to the mid-lower lip and measured the response latency variability and segmental conduction velocity. Results: Responses to electrical stimulation of the unaffected facial nerve were found in all patients. Mean conduction velocity was 49.6 +/- 6.2 m/s between tragus and oral commissure, and 6.0 +/- 1.9 m/s between oral commissure and mid-lower lip. Latency variability was 0.27 ms to facial nerve stimulation and 0.08 ms to oral commissure stimulation. Conclusion: Short distance sprouting of axons that innervate muscle fibers, which originate from the unaffected facial nerve, results in propagation of impulses to muscle fibers in the midline. Muscle Nerve 2011.
Kondo, Y., H. Moriyama, et al. (2011). "The relationship between Bell's palsy and morphometric aspects of the facial nerve." Eur Arch Otorhinolaryngol.
Epidemiological data of Bell's palsy (BP) have been reported. For example, the annual incidence of BP is 15-30 per 100,000 persons, with equal numbers of men and women affected, and there is no predilection for either side of the face. However, details of the relationship between BP and morphometric aspects of the facial nerve have not been available in textbooks. We performed a morphometric analysis of human facial nerve fibers and estimated the total number of myelinated axons (TN) and average transverse area of myelinated axons (ATA). The facial nerve showed a significant decrease of TN with increasing age (r = -0.77; p < 0.01), but showed no significant changes of ATA with age (r = -0.01; p = 0.96). We supposed that the TN decrease with age was a factor in the delayed recovery from BP seen in the elderly. Moreover, the TN and ATA showed no significant differences between female and male specimens (p < 0.05), or between the right and left side specimens (p < 0.05). Our present results seem to explain the absence of significant sex and affected side differences in BP.
Frigerio, A. and P. Cavallari (2011). "A Closed-Loop Stimulation System Supplemented with Motoneurone Dynamic Sensitivity Replicates Natural Eye Blinks." Otolaryngol Head Neck Surg
Objective. The authors are designing an implantable device that will electrically stimulate a paretic eyelid when electrodes implanted into the contralateral healthy orbicularis oculi muscle detect a spontaneous blink activity. As a novelty, the stimulation pattern includes the dynamic sensitivity of motor units, thus obtaining complete eyelid closure, tailored on the kinematics of the natural eye blink.Study Design. A preliminary study was performed on 10 healthy subjects, to observe, first, the kinematics of their natural eye blink and, second, the eye blink stimulated by a dynamic vs nondynamic pattern.Setting. A microaccelerometer taped onto the left upper eyelid detected its kinematics. A dedicated LabView software built up and triggered the stimulation pattern. A webcam recorded the behavioral effect.Subjects and Methods. The kinematics of spontaneous eye blinks was detected. Then, an epicutaneous stimulation of the facial nerve branch for the left orbicularis oculi muscle was performed on the same subjects. Muscle recruitment curves were studied, and acceleration of the bionic blink was measured and compared with the natural one.Results. Kinematics of the natural eyelid is highly variable within subjects. The stimulation pattern frequency was set case by case in order to obtain the desired eyelid acceleration of the contralateral eye. A custom-fit dynamic stimulation leads to a symmetrical natural-like eye blink.Conclusions. By adding the dynamic pulse, the authors were able to tailor a bionic eye blink, which was hardly distinguishable from the subject's natural one.