Intraparotid facial nerve schwannoma: clinician beware

Intraparotid facial nerve schwannomas are rare neoplasms that are challenging to diagnose and manage. Many patients present with a painless, palpable facial mass. The presence of facial paralysis is variable. Imaging studies and fine-needle aspiration cytology are not always helpful in preoperative diagnosis. With early diagnosis of facial nerve schwannoma, management of the patient can be planned and, ultimately, facial nerve function optimized. By reviewing the literature and 2 cases from a series of patients seen in our practice, we provide insight into the current diagnosis and treatment of a rare pathology.

Facial Nerve Grading System 2.0

OBJECTIVE

To present an updated version of the original Facial Nerve Grading Scale (FNGS), commonly referred to as the House-Brackmann scale.

STUDY DESIGN

Controlled trial of grading systems using a series of 21 videos of individuals with varying degrees of facial paralysis.

RESULTS

The intraobserver and interobserver agreement was high among the original and revised scales. Nominal improvement is seen in percentage of exact agreement of grade and reduction of instances of examiners differing by more then one grade when using FNGS 2.0. FNGS 2.0 also offers improved agreement in differentiating between grades 3 and 4.

CONCLUSION

FNGS 2.0 incorporates regional scoring of facial movement, providing additional information while maintaining agreement comparable to the original scale. Ambiguities regarding use of the grading scale are addressed.

[Clinical-electroneuromyographical characteristics of facial nerve paralysis in children]

A clinical-electroneuromyographical study of 40 children (32 (80%) of them aged from 12 to 17 years, mean age 13,9+/-1,8 years, and 8 (20%) - from 1 to 8 years, mean age 4,4+/-2,1 years) were studied in the acute period of facial nerve paralysis (FNP). Six (15%) children had FNP in the anamnesis. Among precipitating factors were the cold exposure the day before disease onset (20 (50%) patients), symptoms of flu (13 (32,5%) patients) and psycho-emotional tension (3 (7,5%) patients). No precipitation was noted in 4 (10%) children. The degree of muscle paresis was 81,9+/-7% that corresponded to clinical stages III-IV according to K. Rosler. An electroneuromyographical analysis of motor ortho- and antidromic response to the facial nerve stimulation on the side of paresis and on the contralateral side in patients and controls revealed the presence of proximal axon- and myelinopathy of facial nerve with the involvement of its own motorneurons and brain stem interneurons. The maintenance of wink reflex and F-wave blocks in the period over 3 weeks are prognostically unfavorable factors for restoration of mimic muscle function in the early stage of disease.

Ramus marginalis mandibulae nervus facialis palsy in hemifacial microsomia

AIM

The paralysis of the ramus marginalis mandibulae nervus facialis may occur in Hemifacial Microsomia (HM); the combination of both HM and palsy contributes to an elongation of the mandibular body. This study explores a possible correlation between neurological deficit, muscular atony, and structural deficiency.

STUDY DESIGN

Of 58 patients with HM who had come to the University of Rome (Sapienza) Pre-surgical Orthodontics Unit, 4 patients were afflicted with Hemifacial Microsomia and ramus marginalis mandibulae nervus palsy; these patients underwent physical, neurological, opthamologic and systemic examinations. The results were then analysed in order to determine a possible correlation between neuro-muscular and structural deficit.

METHODS

Electroneurographic and electromyographic examinations were performed to estimate facial nerve and muscles involvement.

RESULTS

Neuroelectrographic exam showed a damage of the nervous motor fibres of the facial nerve ipsilateral to HM, with an associated damage of the muscular function, while neuro-muscular functions on the healthy side were normal.

CONCLUSIONS

The peripheral nervous and muscular deficits affect the function of facial soft tissues and the growth of mandibular body with an asymmetry characterised by a hypodevelopment of the ramus (due to the HM) and by an elongation of the mandibular body (due to ramus marginalis mandibulae nerve palsy), so that the chin deviation is contralateral to HM. In these forms, a neurological examination is necessary to assess the neurological damage on the HM side. Neuromuscular deficiency can also contribute to a relapse tendency after a surgical-orthodontic treatment.

Canalicular magnetic stimulation lacks specificity to differentiate idiopathic facial palsy from borreliosis in children

OBJECTIVE

To investigate the role of transcranial magnetic stimulation (TMS) to differentiate between idiopathic facial nerve palsy (iFNP) and facial nerve palsy due to borreliosis (bFNP).

PATIENTS AND METHODS

Transcranial and intracanalicular magnetic and peripheral electrical stimulation of the facial nerve together with clinical grading according to the House and Brackmann scale were performed in 14 children and adolescents with facial palsy (median age 11.5 yr, range 4.6-16.5 yr). Serum and cerebrospinal fluid (CSF) were evaluated for antibodies against Borrelia burgdorferi and CSF cell count, glucose and protein content were screened with methods of routine laboratory testing. Data of patients were compared with normal values established in 10 healthy subjects (median age 10.2 yr, range 5.1-15.3 yr).

RESULTS

Patients with iFNP showed a significant decrease in MEP amplitude to canalicular magnetic stimulation compared with healthy controls (p=0.03). However, MEP amplitude did not discriminate sufficiently between the two groups, because the ranges of dispersion of MEP amplitudes overlapped. Patients with bFNP had normal MEP amplitudes to canalicular magnetic stimulation compared with normal subjects.

CONCLUSION

Diagnostic assessment by TMS failed to provide a reliable diagnostic criterion for distinguishing between iFNP and bFNP in children and adolescents.

The usefulness of clinical findings in localising lesions in Bell's palsy: comparison with MRI

BACKGROUND

Although electrophysiological tests and brain MRI provide information about the site of the lesion in Bell's palsy, clinicians usually depend on clinical data. However, the accuracy of clinical findings in identifying lesions has never been evaluated.

METHOD

A total of 57 patients with idiopathic peripheral facial palsy were included in this study. We determined the sites of the lesions based on associated symptoms and by brain MRI. We then compared the two to assess the value of clinical findings in determining lesion sites.

RESULTS

Of the 57 patients, 27 were men. The mean age of all patients was 50.6+/-16.7 years. The lesion sites determined from clinical findings were as follows: the infrageniculate-suprastapedial segment, 13 (23%); the infrastapedial-suprachordal segment, 9 (16%); and the mastoid segment, 35 (61%). No sites were classified as involving the suprageniculate segment. On brain MRI, 51 (89%) of the 57 patients showed abnormal enhancement of the facial nerve, with the most common area being the suprageniculate segment, including the distal intrameatal, labyrinthine and geniculate ganglion.

CONCLUSIONS

We demonstrate that clinical history is not helpful in determining the site of a lesion in Bell's palsy. The segment most frequently involved in Bell's palsy is the suprageniculate segment.

Hemifacial spasm: neurovascular compressive patterns and surgical significance

BACKGROUND

The aim of this study was to report further investigation of neurovascular compression as a cause of hemifacial spasm (HFS) and to provide useful surgical guidelines by describing the compression patterns.

MATERIAL AND METHODS

From January 2004 to February 2006, 236 consecutive patients with HFS underwent microvascular decompression (MVD) in a single centre. Based on the operation and medical records, the intraoperative findings and post-operative outcomes were obtained and analysed.

RESULTS

We found that 95.3% of lesions had accompanying causative factors that made the neurovascular compression inevitable. Based on the contributing factors, compression patterns were categorised into six different types including: loop (n = 11: 4.6%), arachnoid (n = 66: 27.9%), perforator (n = 58: 24.6%), branch (n = 18: 7.6%), sandwich (n = 28: 11.9%), and tandem (n = 52: 22.0%). The compression patterns were significantly correlated with the compressing vessels involved. Thirty-two (86.5%) of 37 lesions where the vertebral artery was the compressing vessel involved the tandem type. Anterior inferior cerebellar artery was the compressing vessel involved in 49 (84.5%) of 58 perforator type compressions, while posterior inferior cerebellar artery was the compressing vessel involved in 8 (72.7%) of 11 loop type compressions.

CONCLUSIONS

Once the compressing vessel responsible for the neurovascular compression are identified, the probable pattern of compression can be anticipated; this knowledge could facilitate the application of the appropriate operative procedures and minimise post-operative complications.

[Evolution of facial nerve prognosis in vestibular schwannoma surgery by translabyrinthine approach]

OBJECTIVES OF THE STUDY

To evaluate our results on the postoperative facial function, its pre and preoperative predictive factors, and the application of the surgical technique to lesions of decreasing size.

PATIENTS AND METHODS

A series of 248 patients operated of an unilateral vestibular schwannoma has been reviewed. We have compared the results gathered over two periods corresponding to the evolution of our surgical technique since 1998.

RESULTS

Immediate and 1 year postoperative facial function is significantly better among patients operated after 1998 (satisfactory in 75 and 88% respectively). This trend marked by the improvement of the results since 1998 has to be discussed according to other predictive factors. One of predictive factor is the decrease of the size of the lesion during the same period. The other factors are the hearing level, deafness duration, trigeminal nerve involved, vestibular status and ABR desynchronization.

CONCLUSION

The positive predictive factors are usually correlated with the size of the tumour This implies the necessity of an early diagnosis of the schwannomas. The second predictive factor of the facial function is the use of a soft surgical technique.

New classification of rating facial nerve dysfunction

In consideration of the complexity of the physiopathology of the facial nerve and to get a standard model of classification of his dysfunction, it appears evident the necessity in the clinical practice to have a rapid, simple and easy system. Grading of facial function is necessary for evaluating and communicating the spontaneous course and the results of medical and surgical treatment. Different grading scales have been proposed but none has been universally accepted; the author revises the principal systems of classification and proposes a new and easy model.

Incidence of dehiscence of the facial nerve in 416 cases of cholesteatoma

OBJECTIVE

To determine the incidence and location of dehiscence of the facial nerve in patients with cholesteatoma.

STUDY DESIGN

Prospective case series.

SETTING

Tertiary referral centers.

PATIENTS

Charts and operative details from 1,372 consecutive chronic ear cases performed by a single surgeon were reviewed for anatomic details regarding the facial nerve. The study group was limited to the 416 ears in which cholesteatoma was confirmed at the time of surgery.

MAIN OUTCOME MEASURES

Facial nerve dehiscence was graded as present or absent for both the tympanic and mastoid segments; the location of dehiscence in the tympanic segment was further characterized in regard to its relationship to the oval window and cochleariform process. Adherence of cholesteatoma to any area of dehiscence was also noted as was the presence of any coexisting inner ear fistula.

RESULTS

Dehiscence of the tympanic segment was present in 18.8% (78 of 416) of ears in the study group. There were five cases of mastoid dehiscence. Approximately 80% of nerves that were dehiscent involved the area just superior to the oval window, and 12% involved the nerve anterior to the cochleariform process. Adults in the study were more likely to have dehiscence than those 18 years and younger (p = 0.0003, chitest), and inner ear fistula was also more common in those with dehiscence (p = 0.0118, chitest). Case studies of cholesteatoma adherent to the facial nerve are reviewed.

CONCLUSION

This study represents the largest group of patients evaluated to date for dehiscence of the facial nerve in the setting of cholesteatoma. Dehiscence is common, especially in patients with cholesteatoma, and the careful surgeon can avoid damage to the facial nerve through understanding of this anatomic variation.

Electrical stimulation of the paralyzed orbicularis oculi in rabbit

Dysfunction of the seventh cranial nerve often results in facial paralysis and loss of the ability to blink the eye, which can lead to corneal scarring, diminished vision, and potential loss of the eye. This study investigated the potential of electrical stimulation of the orbicularis oculi muscle as a means of restoring blink function. An animal model of orbicularis paralysis was created by sectioning the seventh cranial nerve in rabbit. Twenty paralyzed and five normal rabbits were acutely implanted with a subcutaneous stimulating electrode near the margin of the upper eyelid. Biphasic current controlled stimulation pulses were delivered between implanted contacts at the medial and lateral edges of the eyelid. Strength-duration curves for lid twitch threshold were generated, and quantitative measurements of lid closure were made for systematically varied parameters including pulse amplitude, pulse width, number of pulses delivered, and duration of paralysis prior to stimulation. Normal rabbits achieved a greater degree of lid closure due to electrical stimulation than rabbits that had been surgically paralyzed. Of rabbits that had been paralyzed, those demonstrating evidence of at least partial reinnervation achieved a greater degree of lid closure than those demonstrating persistent denervation. Trains of 10 ms biphasic pulses delivered at 50 Hz were found to be the most effective means of eliciting lid closure for the range of parameters tested.

Quality of life after facial nerve repair

OBJECTIVES

Analyze the postoperative quality of life (QoL) in patients after surgical nerve repair for facial nerve lesion.

STUDY DESIGN

Descriptive study using questionnaire data and medical chart review.

METHODS

Forty-nine patients answered the Short Form-36 (SF-36), the European Organization for Research and Treatment (EORTC) questionnaires QLQ-C30 and QLQ-HN35, and a modification of the Acoustic Neuroma Hospital of Norway Survey. Facial function was self-evaluated by the patients using the House-Brackmann (HB) scale and the Stennert index (SI). The questionnaire data were analyzed in relation to the medical chart data.

RESULTS

The follow-up time ranged from 12 to 202 months. The underlying disease was benign in 34 (61%) patients and malignant in 15 (39%) patients. Facial nerve repair was successful in all patients, with a mean HB scale of 3.1, a mean SI of 4.9, and a mean May grading of 2.7. The facial function self-evaluation was not significantly different. Seventy-five percent of the patients were satisfied with the operation. The SF-36 demonstrated a significantly lower social functioning, emotional role, general mental health, and vitality lower than in the normal German population. In the EORTC QLQ C30, emotional function was low and the insomnia rate high. EORTC QLQ HN35 showed a high rate of trouble with social eating, less sexuality, problems opening mouth, and weight gain problems. Age 45 years or older, female sex, May grading 3 or greater, SI self-assessment 5 or greater, HB self-assessment greater than 2 had a significant negative effect on some QoL items, but not factors such as type or histology of the disease or delayed reconstruction.

CONCLUSIONS

Although grading of facial function after nerve repair revealed satisfying results, the patients experience a reduced QoL.

Clinical Outcome After Surgery for 75 Patients With Parotid Sialadenitis

OBJECTIVE

To analyze the clinical outcome of patients treated surgically for chronic parotid sialadenitis.

STUDY DESIGN

A retrospective cohort study of patients whose clinicopathologic information had been collected prospectively onto a dedicated head and neck database.

METHODS

Between 1987 and 2006, a total of 75 patients had 78 parotidectomies, 17 superficial and 61 near-total, to treat chronic parotid sialadenitis. The clinicopathologic data including treatment morbidity and outcome were analyzed.

RESULTS

Temporary postoperative facial weakness occurred in 26 (33%) patients, and this was permanent, although partial, in one (1%) patient. There was no significant difference (P > .05) in the incidence of temporary facial nerve neuropraxia in the superficial (35%) and near-total parotidectomy (33%) groups. Recurrence of symptoms was noted in two patients who had undergone near-total parotidectomy and none of the patients who had undergone superficial parotidectomy. Chronic parotid sialadenitis was effectively treated in 97% of patients undergoing parotidectomy.

CONCLUSION

Near-total parotidectomy is a safe and efficacious surgical treatment in the management of patients with debilitating severe chronic parotid sialadenitis.

Recovery of facial nerve function after repair or grafting: our experience with 24 patients

OBJECTIVE

The aim of this study was to review the outcomes of facial nerve repair and attempt to identify predictors of recovery time.

STUDY DESIGN

A retrospective chart review was conducted.

SETTING

The study was done in a single, tertiary care, otologic referral center.

PATIENTS AND METHODS

Thirty-one patients underwent facial nerve repair or grafting between 1990 and 2003. Twenty-four patients were found to have complete data sets with at least 11-month follow-up. The following data were noted: patient age and sex, preoperative diagnosis and facial nerve status, administration of radiation, surgical procedure performed (including type and length of graft), proximal and distal sites of anastomosis, time interval to first recovery of clinical facial nerve function, and facial nerve status at most recent follow-up.

RESULTS

Nineteen patients had some return of function within 12 months postoperatively. Five patients were lost to follow-up but had no documented facial function at a minimum of 11 months postoperatively. Mean follow-up was 8 months, with a range from 3 to 25 months. Overall mean time to recovery of function was 7 months. Mean times to recovery for each anastomotic site were calculated and found to correlate with recovery times, with an R(2) value of 0.86. A more proximal anastomosis was associated with a longer recovery period. When the data were analyzed individually, no statistical correlation was found between time to recovery of function and patient age, radiation status, length of graft, or site of anastomosis.

CONCLUSIONS

Intuitively, because of technical difficulty and the proximity of injury to the cell body, a more proximal repair would seem to result in slower recovery. In our series of patients undergoing repair or grafting, neither the site of injury and repair nor the length of graft were statistically predictive of recovery intervals. A trend toward longer recovery time with a more proximal anastomosis is likely, however, based on the relationship identified between average recovery times and site of injury. A larger series is needed to identify a significant correlation.

Facial motor function monitored by hand held calipers versus computer-assisted photography

BACKGROUND

It is essential to have easy to use, reliable tools to assess and compare facial function for clinical records, audit and research purposes. In this study, two different techniques were examined, Hand held calipers (HHC, as described by Burres), and computerised analysis of digital photographs (CAOP) using Adobe Photoshop 7. The aim of this study was to determine the level of agreement between two operators (physiotherapist) using HHC to measure the distance between facial landmarks, and the level of agreement between two operators (photographers) using CAOP to measure the same distance between facial landmarks and explore whether these two techniques can be used interchangeably.

METHOD

The distance between facial landmarks was measured, with the face at rest and following four standard facial expressions. All measurements were repeated one week later to permit inter/intra-rater reliability over time to be assessed. Nine female volunteers with normal facial function were included in the study.

RESULTS

The intra- and inter-rater agreement using CAOP was high whereas the agreement was low when using HHC.

CONCLUSION

Hand held calipers proved to be an unreliable technique for monitoring facial function. However digital photography when combined with Adobe Photoshop 7 provides a highly reliable objective measurement tool. It was simple to use, low cost and suitable for use in a clinical environment.

Facial nerve function in carcinoma of the parotid gland

AIM

To analyse, for patients with carcinoma of the parotid gland, the prognostic value for treatment outcome of the function of the facial nerve (NVII), and determining facial nerve dysfunction after treatment.

METHODS AND MATERIALS

In a retrospective study of the Dutch head and Neck cooperative group (NWHHT), data of 324 patients with parotid carcinoma were analysed. The function of N VII before treatment was intact in 77%, partially and completely impaired in 14% and 7%, respectively. Eighty-eight percent of the patients were treated surgically, and 77% of them were treated by a combination of postoperative radiotherapy. In 21% NVII was sacrificed, a reconstruction was performed in one of three.

RESULTS

Independent risk factors for N VII dysfunction before treatment were tumour localisation, positive neck nodes at presentation, pain, increasing age, and perineural invasion. Regional, not local, control was significantly impaired for complete facial paralysis. N VII dysfunction was an independent factor for disease free survival, and was 69%, 37% and 13% for normal, partially and completely impaired function, respectively. After treatment 22% of the patients experienced a partial paralysis, and 13% of the patients experienced a complete paralysis of N VII.

CONCLUSION

For patients with parotid carcinoma, facial nerve function before treatment is a strong prognostic factor for disease free survival.

Chorda tympani nerve transection alters linoleic acid taste discrimination by male and female rats

Taste is intimately associated with food choice, yet little is known about the role of taste in preferences for dietary fat, a major component of many foods. We measured the taste threshold for linoleic acid (LA), an essential free fatty acid found in dietary fat, before and after bilateral transections of the chorda tympani nerve (CTX) in adult male and female rats. We conditioned a taste aversion to 88 microM LA and assessed the generalization of the aversion to lower LA concentrations to determine LA discrimination thresholds. We discovered that female rats had a lower LA discrimination threshold (approximately 2.75 microM LA) than did male rats (approximately 11 microM LA). In another set of animals, we performed CTX and found that CTX elevated LA threshold to the same level (approximately 22 microM LA) in male and female rats. Finally, we evaluated licking responses to 11, 22, 44 and 88 microM LA mixed in sucrose by male rats and ovariectomized (OVX) female rats treated with estradiol benzoate or oil vehicle. All rats increased licking to increasing LA concentrations, but OVX rats responded to a lower LA concentration (22 microM) than did males (44 microM) in 10-s trials. However, estradiol did not affect this outcome. Collectively, these experiments show that male and female rats use taste to discriminate LA and that the chorda tympani nerve, which innervates taste buds on the anterior tongue, plays a role in this discrimination. Furthermore, sex differences in fat preferences may depend on differences in fatty acid taste thresholds as well as on the taste stimuli with which fat is combined.

Frequency and prognosis of delayed facial palsy after microvascular decompression for hemifacial spasm

BACKGROUND

Microvascular decompression (MVD) for hemifacial spasm (HFS) provides a long-term cure rate. Delayed facial palsy (DFP) is not an unusual complication, but it has only been sporadically described in the literature. The purpose of this report is to evaluate the incidence of delayed facial palsy after MVD and its clinical course and final results.

METHODS

From January, 1998 to April, 2004, 410 patients underwent microvascular decompression for hemifacial spasm at our Institute. During this time, 21 patients (5.4%) developed delayed facial weakness; eighteen of them were given steroid medication and they were followed up in the out-patient clinic.

FINDINGS

Twenty-one patients developed DFP after microvascular decompression an incidence of 5.4%. There were seventeen women (81.0%) among the 21 patients with DFP who were included in this study. In twenty of them, the symptoms of HFS improved completely after the operation, but the spasm remained with one of them. The onset of palsy occurred between postoperative day 7 and 23 (average: 12.1 days). The palsy was at least Grade II or worse on the House-Brackmann (HB) scale. The time to recovery averaged 5.7 weeks (range: 25 days-17 weeks); 20 patients improved to complete recovery and 1 patient remained with minimal weakness, as Grade II on the HB scale, at the follow-up examination.

CONCLUSION

Our findings demonstrated that the incidence of DFP was not so low as has been reported the literature, and it did not have any striking predisposing factors. Even though the degree of facial palsy was variable, almost all patients exhibited a complete recovery without any further special treatment. The etiology of DFP and its association with herpes infection should be further clarified.

Chronic Recurrent Subarachnoid Hemorrhage from a Trigeminal Nerve Malignant Peripheral Nerve Sheath Tumor

OBJECTIVE:

Clinically significant intratumoral or peritumoral bleeding from trigeminal nerve tumors is very rare.

CLINICAL PRESENTATION:

We report the case of a 59-year-old man who presented with recurrent subarachnoid hemorrhage from a left trigeminal nerve malignant peripheral nerve sheath tumor. He presented with decreased consciousness, left facial hypesthesia, and left facial weakness. Trigeminal neuralgia was present for 18 months. Cranial computed tomographic and magnetic resonance imaging scans revealed a left parapontine mass with cystic changes and intratumoral bleeding. Furthermore, signs of hemosiderosis of the subarachnoid space were noted. Lumbar puncture revealed fresh bleeding. Angiography detected no aneurysm or other causes of bleeding. The patient became fully alert within hours, the facial weakness improved within a few days. There was no evidence of vasospasm or persisting hydrocephalus. He underwent left-sided suboccipital craniotomy for macroscopically total tumor removal.

INTERVENTION:

The patient underwent total tumor removal via a left suboccipital approach. Intraoperatively, evidence of recurrent intratumoral bleeding was noted. Histological examination revealed a malignant peripheral nerve sheath tumor (World Health Organization Grade III). Postoperatively, the hypesthesia improved significantly. The patient was transferred to radiotherapy for external beam radiation.

CONCLUSIONS:

This is the first report regarding a malignant peripheral nerve sheath tumor of the trigeminal nerve that caused clinically significant subarachnoid hemorrhage caused by intratumoral bleeding.

Young onset hemifacial spasm

INTRODUCTION

Hemifacial spasm (HFS) frequently affects middle aged individuals and the clinical features and etiology have been well reported. However, there is limited data on the exact pathogenesis in young-onset HFS. If age is a major determinant of the etiology or influences the presentation of HFS, there may be clinical differences between the young and elderly HFS patients.

OBJECTIVES

We determined the prevalence, clinical and imaging features of young-onset HFS (age of onset<or=30 years) in a tertiary referral center. These data were compared with old onset (age of onset>or=65 years) HFS patients.

METHODS

We examined consecutive patients clinically diagnosed with HFS in a tertiary referral center. The clinical (demographics, clinical presentation, severity of HFS, associated medical conditions and other variables) and imaging findings of young onset patients and old onset patients were tabulated and compared.

RESULTS

Amongst 230 consecutive HFS patients, 15 (6.5%) were young-onset HFS and 50 (21.7%) were old-onset HFS. In the young-onset HFS, the mean age of onset of symptoms was 26.5+/-6.5 (6-30) years, with 80% women and 75.0% of young onset HFS having neurovascular compression (NVC) of the root exit zone (REZ) of the facial nerve on the ipsilateral side; 86.7% had initial onset of twitching in the upper eyelids that later progressed to the lower facial muscles. While the prevalence of hypertension, diabetes mellitus and other associated vascular disorders in late onset HFS was higher than in young onset groups, the clinical features and frequency of NVC of the facial REZ between the two groups were similar.

CONCLUSIONS

We demonstrated a 6.5% frequency of young-onset HFS in our cohort of HFS and their clinical presentation was similar to the old onset patients. Genetic, anatomic or other unidentified factors may contribute to NVC in young-onset HFS.