Conservative Versus Surgical Therapy in Managing Patients with Facial Nerve Palsy Due to the Temporal Bone Fracture

Abstract

Facial nerve paralysis is classified into immediate or delayed-onset palsy, and affected patients should be treated through conservative or surgical therapy. Appropriate treatment is somewhat debated as well as proper time for performing surgery. This study aimed to assess treatment outcome between conservatively and surgically treated groups and to determine the appropriate time of surgery in selected patients for surgery. Twenty-four patients from April 2008 to July 2015 were included. Performing decompression surgery within the first 2 months following the trauma accompanies a better prognosis (p-value < 0.05). Eleven patients were managed conservatively, and 4 of them demonstrated immediate onset and 7 indicated delayed onset. Nine patients obtained normal nerve function, one patient had partial palsy, and one of them had complete palsy. There was no significant difference in the rate of recovery between types of the treatment (p-value > 0.05). Decompression surgery is recommended in the first 2 months after the trauma for immediate onset and also complete degeneration on electroneuronography.

Facial nerve paralysis (FNP) occurs in approximately 5 to 10% of traumatic patients with temporal bone fractures throughout the world.[1,2,3,4,5,6,7,8,9,10] The major causes of temporal bone fractures are traffic road injuries, falling from height, assault, and gunshot.[6,11,12] Temporal bone fractures are practically classified into otic capsule sparing versus otic capsule involving fracture.[13] Surgeons who manage the traumatic FNP by making their effort in selecting an appropriate therapy encounter a huge challenge due to increasing number of traumatic events and traumatic FNP complications.[4,12,14,15]

Conservative therapy generally should be considered for patients who possess either a normal facial nerve function after injury regardless of progression, with the presentation of incomplete paralysis with any progression to complete paralysis or less than 90 to 95% degeneration on electro-neuronography (ENoG), but decompression surgery is mandatory as the therapy for those who exhibit complete facial nerve palsy which accompanies poorer prognosis.[3,4,6]

FNP associated with the temporal bone fracture is classified into immediate palsy or delayed one, depending on the onset which occurs after the trauma.[16,17] Although there is an emphasis on performing decompression surgery shortly after trauma, effective result for delayed decompression surgery was reported as well.[15,16,18,19] Hence, there is a debate over the appropriate time for performing decompression surgery.

In this study, we evaluated a series of patients with facial nerve palsy secondary totemporal bone fracture. The main aims of this study were to assess posttreatment outcome between conservatively and surgically treated groups and to determine the appropriate time of surgery in selected patients for surgery.

Materials and Methods

Including and Excluding Criteria 

All patients who were admitted into two of our educational hospitals with posttraumatic facial nerve palsy due to temporal bone fracture from April 2008 to July 2015 were retrospectively reviewed. All patients—who were surgically or conservatively managed—with facial nerve palsy resulting from temporal bone fractures were included. Those ones who had the temporal bone fracture without facial nerve palsy were excluded. In total, 25 patients were involved in our study.

Patients Assessment 

Patients were precisely evaluated through audiological evaluation, including air-bone conduction pure-tone audiometry, tympanometry, and stapedial reflex measurement[20,21,22] (

Table 1. All studied demographics of all patients.

Abbreviations: ENoG, electroneuronography; HB, House–Brackmann; Postop, postoperative; Preop, preoperative.

). ENoG demonstrated more than 90% degeneration (complete degeneration) for 19 patients (79%) (Figure 1). House–Brackmann (HB) grading system which is commonly used to assess facial nerve function for patients were applied to evaluate the outcomes after either decompression surgery or conservative therapy.[23] To make a better judgment in comparing pretreatment versus posttreatment outcomes, facial nerve function was classified into three subgroups: HB grades I and II were representing normal nerve function, grades III and IV were considered as partial palsy, and grades V and VI were representing complete palsy.

Patients Demographics 

The sample included 19 males (79%) and 6 females (21%), with the age ranging from 14 to 58 years (mean: 31.6 years, SD: 14 years), and all (100%) had unilateral facial nerve palsy as a result of unilateral temporal bone fractures (Table 1). Road traffic injuries were the leading cause of facial nerve palsy.

Details of Treatment of Patients 

All the patients have managed by otolaryngology department. Once the full evaluation had been completed, a decision for managing the patients was made based on their initially performed ENoG which plays a crucial role in managing such patients. Decompression surgery was considered in those patients whom ENoG demonstrated more than 90% degenerated fibers, refractory ENoG results to medical treatment, or there has been axonal degeneration on electromyography lately with no sign of recovery. In circumstances where ENoG demonstrated less than 90% degeneration, conservative therapy was predominantly considered for managing such patients. The same dose of methylprednisolone, aggressive steroid therapy, was administered to both medically and surgically treated groups, it was continued, and tapered off within 2 weeks after it had commenced. Decompression surgery for all the patients was performed through either extended transmastoid approach described by Yanagihara or transmastoid decompression of labyrinthine-meatal segment of the facial nerve described by Keles et al.[24,25] The meantime for the first examination after decompression surgery was between 6 months and 6 years.

Data Analysis 

Data analysis was performed by using Stata software. Pearson’s correlation coefficient formula, chi-square test (χ²), and two-sample t-test, as appropriate tests, were employed for data analysis. Quantitative data were expressed as numbers (%).

Results

Surgically Treated Group 

This group is consisted of 14 patients, including 11 (78%) males and 3 (22%) females (

Table 2. Demographics of patients who underwent surgical treatment.

Abbreviations: ENoG, electroneuronography; HB, House–Brackmann; Postop, postoperative; Preop, preoperative.

). According to the findings of computed tomography, type of fracture was detected as follows: 6 (43%), 6 (43%), and 2 (14%) of the patients had otic involving fracture, otic-sparing fracture, and without any fracture line, respectively. Palsy characteristics in nine (64%) patients were categorized as immediate-onset palsy and the rest of them (36%) were categorized as unknown onset due to their declined level of consciousness. More than 90% degeneration on preoperative, ENoG (HB grade VI; complete palsy) was noted for all the patients (100%) belonging to this group at the initial assessment. On the last examination after the decompression surgery, facial nerve function was re-evaluated. Of 14 cases, 3 (21%), 4 (29%), 2 (14%), 1 (7%), 3 (21%), and 1 (7%) of patients had HB grades I, II, III, IV, V, and VI, respectively. In total, seven (50%) of the patients achieved normal facial nerve function (HB grades I and II); 3 (21%) of them demonstrated partial palsy (HB grades III and IV); and 4 (29%) of them were suffering from complete palsy (HB grades V and VI). The mean score of postoperative HB grade was 3.14.

Surgery Time 

Although eight patients (57%) underwent decompression surgery within the first 2 months after the trauma (Figure 2), decompression surgery was performed on six (43%) of them after the first 2 months after the trauma (mean: 140 days) (Figure 3). There was a significant difference in the final outcome between the two groups which underwent surgery before and 2 months after surgery (p = 0.017).

Conservatively Treated Group 

Eleven patients (44%) were managed conservatively. Thisgroup has eight males (72.7%) and three females (27.3%;

Table 3. Demographics of patients who were treated through conservative therapy.

Abbreviations: ENoG, electroneuronography; HB, House–Brackmann.

). According to the initially performed computed tomography findings, two (18.11%), five (45.5%), and four (36.4%) patients had otic involving fracture, otic sparing, and no fracture line, respectively. At the initial assessment, four (36.4%) demonstrated immediate-onset palsy, seven (63.6%) indicated delayed-onset palsy, and none of them was considered as unknown onset palsy. All the patients belonging to this group were treated conservatively, and methylprednisolone was the drug of choice. After the treatment, nine (81.81%) patients obtained normal nerve function (HB grades I and II), one of them (9%) had partial palsy (HB grades III and IV), and the last patient had complete palsy (HB grades Vand VI). Sevenpatients (63%) had delayed onset of facial palsy and all of them attained normal function. According to ENoG, six cases had partial degeneration (<90%), and all of them recovered the normal function with conservative therapy.

Discussion

Considering the study, we assessed treatment outcome between medically and surgically treated groups and also determined the appropriate time of decompression surgery in selected patients based on their initially performed ENoG and their respond to the aggressive steroid therapy.

Corresponding other studies, the major cause of facial nerve palsy and temporal bone fractures was traffic crashes in the study.[6,11,17] Hence, the temporal bone fractures are classified into three categories: longitudinal fractures, transverse fractures which are more related to oticcapsule involving fractures, and mixed fractures.[26,27,28,29] There was no significant difference (p = 0.709) in the rate of facial nerve function recovery after treatment among the three types of fracture which was expected prior to the study, and it reveals that there is no definitely grim prognosis associated with otic involving fractures.

Of the 25 patients in the study, 16 (64%) patients demonstrated normal facial nerve function after the treatment, 4 (16%) indicated partial palsy, and 5 (24%) encountered complete palsy, which is a catastrophic event.

There was a significant difference (p = 0.109) between the percentage of degeneration on ENoG, which was achieved through initially performed ENoG and posttreatment of facial nerve function recovery. On the contrary, complete degeneration on the initial ENoG deteriorates the prognosis than partial degeneration; however, distinct outcomes were reported by Turel et al[30] who described a significant relationship between pretreatment and post-treatment facial nerve function.

In this study, there was a significant difference (p = 0.109) in the rate of facial nerve function recovery between delayed-onset and immediate-onset groups. It can be drawn that all the patients with the delayed-onset palsy ultimately achieved normal facial nerve function. The cause of the mentioned dramatically recovery is probably associated with edema and/or hematoma and the type of facial nerve injury which is either neuropraxia or axonotmesis. Definitely, surgery is mandatory in case of progression of injuries in delayed-onset palsy.

In the series of Quaranta et al[19] where nine surgical patients who were followed up for at least 1 year, 77% of understudied population showed complete recovery, and treatment of patients through surgery was recommended by them, but there was no significant difference (p = 0.255) in the severity of facial nerve palsy after the treatment between surgically treated group and medically treated group. Consequently, the following theories can be drawn. First, there is no superiority of the decompression surgery over the conservative therapy for those who underwent decompression surgery. Second, related criteria for selecting patients for decompression surgery were highly accurate. The second theory seems to be more logical due to the following reasons: first, we did not perform decompression surgery immediately after the trauma; therefore, surgery was indispensable unless the patients did not encounter any degree of improvement. Second, conservative therapy was considered as the appropriate therapy for either patients with delayed-onset palsy or patients with partial degeneration which was noticed by the initial ENoG. Undoubtedly, making a definite decision to manage the patients through either conservative therapy or decompression surgery is difficult because conducting a prospective randomized controlled trial is almost infeasible, and similar results were reported in the systematic review of Nash et al[31] as well.

Yetiser et al[12] in their retrospective case series suggested that preferable time for surgery is between 16 and 105 days after injury. Similarly, in here, there was a significant difference (p = 0.017) in the rate of facial nerve function recovery between patients who underwent decompression surgery within 2 months after trauma and patients who underwent decompression surgery after 2 months of trauma. Accordingly, to the probability of 95%, patients who underwent decompression surgery within 2 months after trauma will be able to achieve better prognosis than those who underwent decompression surgery after 2 months. Our study indicates that the most desirable and effective surgery time is within the first 2 months after trauma whereas Hato et al[16] recommended an ideal time for decompression surgery within the first 2 weeks after trauma in patients with severe, immediate-onset paralysis. Proper surgery timing was remained obscure in the study by Sanus et al.[18] Irrespective of the fact that decompression surgery was performed, four patients had dreadful prognosis (complete palsy) because decompression surgery was considered for all of them after 2 months. In contrast, satisfactory achievement in facial nerve function regardless of surgery timing was reported by Ulug and Arif Ulubil.[15] In our opinion, irreversible destructive changes occur 2 months after the trauma, destroying the entire axon and endoneurium tubules. Accordingly, decompression surgery for eligible patients should be considered within 2 months following the trauma.

Conclusion

According to this study, performing decompression surgery is recommended for the patients with immediate-onset FNP secondary to the temporal bone fracture with complete degeneration on electrophysiological tests, and the appropriate time for decompression surgery is within the first 2 months following the trauma. Conservative therapy could be considered in either delayed-onset or incomplete degeneration which are indicators of pleasant prognosis.