|Year : 2019 | Volume
| Issue : 1 | Page : 11-17
Surgical management of traumatic intratemporal facial nerve paralysis: Looks matter!
Uma Patnaik1, Garima Upreti2, Ajith Nilakantan3
1 Department of Otorhinolaryngology-Head and Neck Surgery, Command Hospital, Southern Command, Pune, Maharashtra, India
2 Department of Otorhinolaryngology-Head and Neck Surgery, Army College of Medical Sciences and Base Hospital, Delhi, India
3 Department of Otorhinolaryngology-Head and Neck Surgery, Military Hospital, Pathankot, Punjab, India
|Date of Web Publication||19-Jun-2019|
Dr. Garima Upreti
51-D, Pocket-B, Siddhartha Extension, New Delhi - 110 014
Source of Support: None, Conflict of Interest: None
Objective: Patients with traumatic intratemporal facial paralysis often present late to the otologist, as assessment may be difficult due to altered neurological status, or the management of associated neurosurgical emergency takes precedence. Recommendations for surgical management of these patients are contentious, especially when the patient presents late to the otologist or when the history is dubious. The purpose of this study was to analyze the outcomes of surgery in these patients with regard to onset, clinical findings, timing of surgery, and recovery of facial nerve (FN) function; compare it with similar studies conducted in the past decade; and propose a management guideline for such cases. Study Design: Prospective cohort study. Methodology: Outcome analysis in patients who underwent surgical exploration for traumatic intratemporal FN paralysis at our tertiary care center from January 2008 to December 2015 was done. A detailed record of the history of onset and clinical findings with preoperative status of FN function and hearing status was made. Radiological findings and electrodiagnostic tests influenced the decision-making with respect to surgical exploration. Our observations regarding timing of surgery post trauma, intraoperative findings, and postoperative recovery of FN function were evaluated and outcomes were compared with similar studies in the last decade. Results: Eleven patients were included in the study. All patients had House–Brackmann Grade (HBG) V/VI paralysis prior to surgery. Time interval between injury and surgery ranged between 5 and 176 days (average 58 ± 55 days). Follow-up after surgery ranged from 9 to 72 months (average 31 ± 18 months). Two patients recovered to HBG I, 5 to HBG II, and 4 to HBG III. Conclusion: Surgical exploration for traumatic facial paralysis is often delayed due to late presentation to the otologist. Surgery should not be denied to patients presenting late, or with uncertain history, as it will still give significant recovery to the patient. We have also proposed a guideline for the management of such cases.
Keywords: Facial decompression, facial nerve paralysis, recovery of function, surgical exploration, surgical timing, temporal bone trauma
|How to cite this article:|
Patnaik U, Upreti G, Nilakantan A. Surgical management of traumatic intratemporal facial nerve paralysis: Looks matter!. Indian J Otol 2019;25:11-7
|How to cite this URL:|
Patnaik U, Upreti G, Nilakantan A. Surgical management of traumatic intratemporal facial nerve paralysis: Looks matter!. Indian J Otol [serial online] 2019 [cited 2020 Sep 21];25:11-7. Available from: http://www.indianjotol.org/text.asp?2019/25/1/11/260721
| Introduction|| |
Facial nerve (FN) paralysis is associated with an immense psychosocial impact. Following Bell's palsy, temporal bone trauma is the second most common cause of FN paralysis in adults (17%) and the most common cause in children (30%). The effects are explicit with not just the cosmetic disfigurement, but also the associated physical morbidity, including poor eyelid closure, exposure keratitis, drooling of saliva, hyperacusis, and loss of taste sensation on the affected side. Hence, the onus lies on the surgeon to give the patient the best possible result, with due deliberation.
The onset and progression of facial paralysis post trauma are opined to be important predictors of the recovery of FN function, although these are often difficult to determine at initial presentation. Assessment of FN function may be difficult due to altered neurological status of the patient or because the management of associated neurosurgical emergency takes precedence. This often leads to late presentation to the otologist.
Management protocols for traumatic intratemporal FN paralysis and recommendations for surgical exploration lack clarity and objectivity, particularly in patients presenting late. Most reports are clinical case series with varied treating protocols, based on personal opinion of the treating team.
Therefore, management of these cases warrants cogitated decision-making vis-à-vis performance of electrodiagnostic tests, neuroimaging, and the timing of surgical intervention, especially in cases of delayed presentation or absence of accurate clinical history.
The aim of this study was to analyze the outcomes of surgical management of traumatic intratemporal FN paralysis, compare our outcomes with the available literature on the subject in the last decade, and formulate guidelines for the management of such cases.
| Methodology|| |
This study was carried out at a tertiary care center from 2008 to 2015.
The clinical records of all patients who presented with traumatic FN paralysis, in the stipulated study period, were reviewed. Of these, the cases managed by surgical exploration of the FN were included in the study.
- Patients with traumatic intratemporal FN paralysis
- Patients managed by surgical decompression
- Patients under a minimum of 6-months postoperative follow-up.
- Patients with supranuclear facial palsy and affection of meatal segment or extratemporal part of the FN
- Patients managed conservatively
- Patients lost to follow-up (<6 months postoperatively).
The demographic profile and clinical history of patients, pertaining to the mode of injury, the onset of facial asymmetry, any comorbidities or neurosurgical intervention, and time of presentation to the otologist for facial asymmetry post trauma, were noted. A record of clinical examination including otoscopic findings, tuning fork tests, free-field hearing, and neurological examination was made. In addition, a note of preoperative FN function (based on House Brackmann grading [HBG] system) was made. Assessment of preoperative hearing status was done based on four-frequency pure-tone average.
All patients underwent high-resolution computed tomography (HRCT) of temporal bone at the earliest. Any temporal bone fracture (otic capsule violating or sparing) was noted. Furthermore, the segment of FN involved was identified.
These consisted of electroneurography (ENoG) and electromyography (EMG), which were performed depending on the time interval between the onset of facial paralysis and presentation to hospital for the same.
Patients presenting between 3 days' and 3 weeks' time were evaluated by ENoG (EMG was performed in cases showing >90% degeneration), while those presenting after 3 weeks were evaluated by EMG alone. In cases where history was not known, both serial ENoG and EMG were performed.
Degeneration of >90% FN fibers on ENoG and absence of renervation potentials on EMG were the criteria for surgical exploration.
The surgical approach for FN exploration was determined by the segment of nerve involved (HRCT findings) and the preoperative hearing status. For surgical decompression, transmastoid approach was used to expose the vertical (mastoid) segment, followed by posterior tympanotomy (with the removal of incus) for exploring the horizontal (tympanic) segment up to the first genu.
Postoperative course and follow-up
All patients were administered systemic antibiotics (third-generation cephalosporins) for 5 days and systemic corticosteroids (prednisolone at a dose of 1 mg/kg body weight) for 10 days postoperatively (stopped after tapering down the dose).
In addition, all patients were advised daily facial physiotherapy starting the 6th postoperative day.
The patients were followed up at monthly intervals for the first 6 months, and 6 monthly thereafter. HBG system was used to assess the FN recovery at each visit.
| Observations and Results|| |
Between April 2008 and June 2015, 11 patients underwent surgery for traumatic FN paralysis at our institute.
Of these, 7 were male and 4 were female, with a mean age of 40.82 (± 15.8) years.
The mode of trauma was road traffic accident in six patients, injury due to fall in four patients, and assault in one patient.
The left side of the face was affected in seven patients and the right side in four patients. Prior to surgery, four patients had HBG V paralysis and seven had HBG VI paralysis.
All the patients had hearing loss in the moderate category and beyond on pure-tone audiogram.
On radiological imaging, only the tympanic segment was involved in two patients, only the mastoid segment in three patients, and both tympanic and mastoid in six patients.
Electrophysiological tests were used to define the criteria for surgery (as mentioned previously). The time interval between injury and surgery ranged between 7 and 176 days (average 58 ± 55 days). Intraoperative findings included temporal bone fracture line extending onto Fallopian canal More Details [Figure 1], impinging bone spicules [Figure 2], hematoma, edema, granulation tissue, and fibrotic bands along the facial nerve. The integrity of the nerve was not disrupted in any case. The nerve was decompressed for 180° of its circumference, and the nerve sheath was incised longitudinally, up to 1 cm proximal and 1 cm distal to the site of affection.
|Figure 1: Fracture line extending from squamous temporal bone till tympanic segment of the facial nerve|
Click here to view
The postoperative period of all patients was uneventful. Follow-up after surgery ranged from 9 to 72 months (average 31 ± 18 months). Two patients recovered to HBG I, five to HBG II, and four to HBG III.
Of the five patients who underwent surgery within 21 days of trauma, two recovered to HBG I and three to HBG III. Out of the six patients who underwent surgery after 3 weeks up to 176 days post trauma, two recovered to HBG II and four to HBG III.
Our observations and outcomes are summarized in [Table 1] and [Table 2], respectively.
| Discussion|| |
Acute facial paralysis develops within 24 hours of injury, while delayed paralysis onsets beyond 24 hours post trauma. In a patient presenting late to the otologist, delayed presentation does not necessarily imply delayed onset. The optimal management strategy is then guided by various factors including electrophysiological tests, imaging, and time elapsed post trauma [Figure 3].
|Figure 3: Algorithm for the management of traumatic intratemporal facial nerve paralysis as followed at our institute|
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ENoG is the most accurate electrophysiological test for traumatic FN paralysis if performed within the first 3 weeks of trauma. Typically, ENoG testing is not performed until 3 days after the development of complete unilateral paralysis because Wallerian degeneration More Details does not become apparent until 48–72 h after acute injury to the nerve. Other end of the window period is 21 days post onset of paralysis, as by this time, the nerve degeneration is complete and the nerve excitability is lost. In addition, ENoG may be interfered by possible regeneration of nerve tubules which begins at 2–3 weeks.
EMG is the sole electrophysiological test, useful after loss of nerve excitability and completeness of degeneration, i.e., after 3 weeks. Fourteen days post onset, fibrillation potentials or positive sharp waves seen on EMG can confirm the degeneration of FN. In addition, polyphasic reinnervation potentials may be seen as early as 4–6 weeks after the onset of paralysis.
Fisch and Esslen indicated that if the FN degeneration is >90% on ENoG within the first 2 weeks of trauma, the injury is severe and the recovery of function is poor. Patients, whose degeneration does not reach 90% on ENoG during the first 3 weeks of paralysis, have an excellent chance of regaining full function without sequelae.,,, These authors recommended that ENoG should be repeated every 3–5 days until a trend towards improvement or degeneration >90% is noted. Contrary to these studies, Darrouzet et al., in their retrospective study, underlined that EMG is of much greater value because patients are usually referred to the otologist in the 3rd week after trauma.
In our study, ENoG was useful in early decision-making, while EMG was used for patients presenting beyond 3 weeks of onset of paralysis. Patients in whom a history of onset was not known underwent ENoG/EMG depending on duration from the date of trauma as shown in the [Figure 3]. The decision to perform surgical exploration was taken if ENoG depicted >90% degeneration and/or absence of reinnervation potentials on EMG.
Choice of surgical approach
The choice of approach for FN exploration depends on the possible site of injury and audiological status of the affected ear. Some authors advocate complete FN decompression,, (using translabyrinthine approach in patients lacking serviceable hearing, and transmastoid + middle cranial fossa approach for patients with serviceable hearing), while others propagate limited exploration of FN based on clinical and radiological findings., This is because FN paralysis (when nerve is not transected) occurs more commonly due to the entrapment of nerve within fibrous tissue contiguous to fracture and not due to nerve edema within the labyrinthine segment of the fallopian canal, unless that itself is the site of injury.
When the pathology is clearly localized to the tympanic or mastoid segments of the FN, transmastoid extralabyrinthine approach with posterior tympanotomy helps preserve the posterior canal wall, without violating the labyrinth. Important landmarks for this approach include the lateral semicircular canal, fossa incudis, and digastric ridge. The incus can be removed to achieve decompression of the tympanic segment all the way to the geniculate ganglion. The transmastoid approach also has the advantage of the opportunity for simultaneous reconstruction of ossicle disarticulation, closure of perilymph fistula, and closure of tympanic membrane perforation.,
In our study, HRCT temporal bone assessment revealed the most likely site of trauma to be localized to the vertical and/or horizontal segments of the FN. Based on radiological imaging and clinical evaluation, transmastoid approach with posterior tympanotomy and incus replacement technique was chosen in our cases, thereby evading the morbidity of a large mastoid cavity and offering an opportunity for hearing reconstruction/rehabilitation in the same ear later. In all cases, we opened the fallopian canal at the fracture site, decompressing the nerve 1 cm proximal and distal to the involved segment and did not perform additional decompression of the FN at normal sites.
Timing of surgery and outcomes
The timing of surgery in traumatic intratemporal FN paralysis has been a matter of debate. Fisch advocates immediate exploration in a patient with delayed-onset facial paralysis, showing >90% degeneration of fibers within 6 days of onset, with the view that evacuation of intraneural hematoma will improve the nerve function. He proposed that acute-onset paralysis should be operated after 3–4 weeks, by which time, the concomitantly sustained injuries are managed and evaluation becomes easier.
Chang and Cass recommended early surgical exploration within 2 weeks, based on their review of basic research studies using animal models of traumatic FN paralysis, reasoning that it would significantly reduce the damage to endoneural tubules, thereby improving outcomes.
Hato et al. in their study of 66 cases reported that the rate of complete recovery was 85.7% if surgery was performed within 2 weeks with significantly better prognosis versus those who underwent surgery at 2 weeks to 2 months (47.1%). The rate of complete recovery was 16.7% in patients who underwent surgery after 2 months, resulting in a significantly poorer prognosis.
On the contrary, there have been studies analyzing the effects of late surgery in patients with immediate posttraumatic FN paralysis, showing that patients who were operated on relatively late were found to have better facial recovery.,,, Lieberherr et al. operated on patients with acute FNP, with >90% nerve degeneration on ENoG, 1–3 months following the trauma, and found that 53%–100% of the FN function returned to normal. McKennan and Chole found different degrees of recovery of the FN function according to the HB scale in patients who were operated either early or late following the trauma. Sanus et al. too have reported that late decompression was not associated with a poor outcome and all patients' FN function recovered to at least HBG III, with mean operation time in their series being 70.1 days, ranging from 21 to 160 days. Quaranta et al. included 13 patients with acute FN injury in their series and found that good recovery is also seen in patients who underwent decompression surgery even 3 months after trauma.
In our series, the time interval between injury and surgery ranged between 7 and 176 days (average 58 ± 55 days). Seven patients recovered to HBG I/II and four to HBG III.
Of the 11 patients, five underwent surgery within 3 weeks post trauma and all of them had good recovery of FN function (i.e., HBG I/II). Among the six patients who underwent surgery beyond 3 weeks, two (33.3%) recovered to HBG II, while four (66.6%) recovered to HBG III.
The delay in surgery was mainly due to the late first evaluation and the late referral. However, late decompression was not associated with a poor outcome and all patients' FN function recovered at least to HBG III. Hence, in our opinion, it is better to operate than wait and watch, in patients meeting the criteria, even in late presenting cases.
The outcomes of surgery in cases of traumatic intratemporal FN paralysis in various studies of last decade have been compiled in [Table 3].
|Table 3: Outcomes of surgery in cases of traumatic intratemporal facial nerve paralysis in various studies of the last decade|
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| Conclusion|| |
Surgical intervention is often delayed in patients with traumatic FN paralysis because of multisystem affection, improper evaluation due to altered consciousness, or neurosurgical emergency, management of which takes priority.
Our study revealed that even though early surgery gives the best chance of recovery to the patient, FN decompression performed even up to 6 months post trauma is beneficial.
Hence, surgery should not be denied to patients presenting late with traumatic intratemporal FN paralysis.
HRCT of temporal bone has a role in identifying the site of affection of FN and impacts decision-making with regard to the surgical approach adopted.
Electrophysiology, though not a necessity, aids clinical decision-making, especially in cases where history regarding the onset of paralysis is dubious [Figure 3].
The number of cases is relatively small to perform a convincing statistical analysis.
With none of our cases having fracture site at labyrinthine/meatal segments, the results cannot be generalized for these fracture sites.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]