|Year : 2021 | Volume
| Issue : 4 | Page : 144-147
Late facial nerve paralysis following tympanomastoid surgery: Our experiences at a tertiary care teaching hospital of Eastern India
Santosh Kumar Swain, Satyabrata Acharya, Nibi Shajahan
Department of Otorhinolaryngology and Head and Neck Surgery, IMS and SUM Hospital, Siksha “O” Anusandhan University, Bhubaneswar, Odisha, India
|Date of Submission||01-Jul-2021|
|Date of Decision||28-Jul-2021|
|Date of Acceptance||28-Jul-2021|
|Date of Web Publication||20-Oct-2021|
Dr. Santosh Kumar Swain
Department of Otorhinolaryngology and Head and Neck Surgery, IMS and SUM Hospital, Siksha “O” Anusandhan University, K8, Kalinga Nagar, Bhubaneswar - 751 003, Odisha
Source of Support: None, Conflict of Interest: None
Background: Although uncommon, late or delayed facial nerve paralysis has been reported after tympanomastoid surgeries. The exact etiopathogenesis for late-onset facial nerve paralysis after tympanomastoid surgery is still debatable. Objective: The objective of the study was to assess the potential etiology and outcomes of the late facial nerve paralysis after the tympanomastoid surgery. Materials and Methods: Eighteen patients of the late facial nerve paralysis out of the 1434 cases after tympanomastoid surgery were analyzed. The potential etiologies of the late facial nerve paralysis and its outcome were evaluated. Results: There was fallopian canal dehiscence in 10 patients (55.55%) out of the 18 patients with late-onset facial nerve paralysis in contrast to 262 of 1434 patients (18.27%) without late facial nerve paralysis (P < 0.01). Chorda tympani nerve was injured in three cases (16.66%) and overstretched in three cases (16.66%) whereas 2 (11.11%) had herpes labialis out of the 18 patients with late-onset facial nerve paralysis after tympanomastoid surgery. Conclusion: The risk for late/delayed facial nerve paralysis after tympanomastoid surgery is very rare. Exposure of the facial nerve and fallopian canal dehiscence is important risk factors for late facial nerve paralysis after tympanomastoid surgery. The viral reactivation and injury of the chorda tympani nerve may be triggered factor for the late facial nerve paralysis. The outcome of the posttympanomastoid surgery late facial nerve paralysis is excellent.
Keywords: Dehiscent fallopian canal, late facial nerve paralysis, latent virus, tympanomastoid surgery
|How to cite this article:|
Swain SK, Acharya S, Shajahan N. Late facial nerve paralysis following tympanomastoid surgery: Our experiences at a tertiary care teaching hospital of Eastern India. Saudi J Otorhinolaryngol Head Neck Surg 2021;23:144-7
|How to cite this URL:|
Swain SK, Acharya S, Shajahan N. Late facial nerve paralysis following tympanomastoid surgery: Our experiences at a tertiary care teaching hospital of Eastern India. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2021 [cited 2022 Jul 1];23:144-7. Available from: https://www.sjohns.org/text.asp?2021/23/4/144/328727
| Introduction|| |
Facial nerve paralysis is the most noticeable cranial neuropathy in clinical practice. Facial nerve paralysis is a well-recognized complication of the tympanomastoid surgery. The onset of the facial nerve paralysis may be immediate or late by several days. The immediate facial nerve paralysis is usually occurred by the direct damage to the facial nerve during the surgical procedure. Immediate postoperative facial nerve paralysis may also occur by the effect of the local anesthesia which regresses completely within a few hours. The facial nerve paralysis results in an obvious facial deformity and badly affects the emotional expression of a person which leads to social isolation and minimize the self-esteem of a person with facial nerve paralysis. Facial nerve injury after tympanomastoid surgery is the surgeon's greatest fear for handling the psychological trauma of the patient by cosmetic deformity of the patient's face. Despite advancement in the operating microscope, microdrill, and the availability of the preoperative imaging nowadays, minimizing the risk of facial nerve palsy after tympanomastoid surgery. Tympanomastoid surgery is a common surgical procedure performed routinely by otolaryngologists or otologists. The late facial nerve paralysis after tympanomastoid surgery is uncommon in clinical practice. The incidence of the delayed or late facial nerve paralysis after tympanomastoid surgery is ranged from 0.38% to 1.4%. There is a number of etiological factors have been postulated in the pathogenesis of the late-onset facial nerve paralysis including secondary to surgical trauma, neural edema, local anesthetic drugs, and viral reactivation. Therefore, identifying the exact etiology of this clinical entity has an important implication for the management and also the final outcome.
The late-onset facial nerve paralysis after tympanomastoid surgery has been infrequently reported in the literature. The aim of this study is to discuss the possible etiology and outcomes of the late-onset facial nerve paralysis after tympanomastoid surgery.
| Materials and Methods|| |
This is a retrospective observational study conducted in a tertiary care teaching hospital. There were 18 cases of late or delayed facial nerve paralysis selected between March 2010 and March 2021 among 1434 cases who underwent tympanomastoid surgery. This study was approved by the Institutional Ethics Committee of our hospital (Reference number IEC/IMS/SOA/12/14 February 2010). Late or delayed facial nerve paralysis was defined as onset of facial palsy 72 h after surgery. The inclusion criteria of this study were the patient who developed facial nerve paralysis after 72 h of the tympanomastoid surgery. The exclusion criteria include the patients those facial nerve paralyses before tympanomastoid surgery and who developed immediately after the tympanomastoid surgery. All the enrolled participants were reviewed for the presence of postoperative delayed facial nerve palsy. The onset of late facial nerve paralysis, severity, recovery, and duration of the paralysis were retrospectively documented and analyzed. The House-Brackmann grading for the facial nerve function was used in patients with late facial nerve paralysis following tympanomastoid surgery. The detailed clinical features were collected and analyzed.
All the data were recorded and analyzed using the Statistical Package for Social Sciences (SPSS) software (Version 20) (IBM, Chicago, Illinois, USA). Chi-square test was used for comparing the difference in the incidence of Fallopian canal More Details dehiscence. P < 0.05 indicated that the difference was statistically significant.
| Results|| |
All of the 18 patients those enrolled in this study had chronic otitis media. Late facial nerve paralysis [Figure 1] occurred on days 3 and 10 days after the surgery (mean: 4.3 days). There were 11 males and seven females with male to female ratio of 1.5:1. The age range of the participants was 16 years–65 years with the mean age of 38.6 years. Out of the 18 patients, 12 were diagnosed with chronic otitis media with cholesteatoma where 11 underwent modified radical mastoidectomy and 1 underwent radical mastoidectomy. Rest of the six patients were also chronic otitis media with tubotympanic type and out of them three underwent only myringoplasty and three underwent ossiculoplasty [Table 1]. Fallopian can exploration was done in all the cases. All the cases started with oral prednisolone (1 mg/kg/day) in tapering dose for 3 weeks. Two cases were additionally taken acyclovir for the development of the herpes labialis. In this study, facial nerve paralysis was reached to the peak by 72 h and the grading of the facial nerve function was Grade II-III during the peak period. Among 18 patients, 2 (11.11%) had herpes labialis and the serological confirmed the presence of immunoglobulin M (IgM) antibody to varicella-zoster virus. During tympanomastoid surgery, the fallopian canal dehiscence at the horizontal segment of the facial nerve was found in 10 (55.55%) out of 18 patients [Table 2]. However, the dehiscence of the fallopian canal was seen in 262 of 1434 patients (18.27%) without late facial nerve paralysis, with a statistically significant difference (P < 0.01). The remaining eight cases had intact fallopian canal of which chorda tympani nerve was injured in three cases (16.66%) and overstretched in three cases (16.66%). All 18 patients recovered completely with treatment without any sequelae. Out of 18 patients, 12 recovered completely within 10 days, seven patients returned to normal level within 3 weeks and one patient backed to Grade-I by 6 weeks.
|Figure 1: Patient showing late onset right side facial nerve paralysis following 5th day oftympanomastoid surgery|
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|Table 2: Etiological profile of late facial nerve paralysis following tympanomastoid surgery (n=18)|
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| Discussion|| |
Facial nerve is a unique cranial nerve which supply the muscles of the facial expressions and its injury result in a negative impact on the patient's psychology. The incidence of the facial nerve paralysis with tympanomastoid surgery has been documented to be 0.6–3.7%. In the case of revision mastoid surgery, the chance of facial nerve paralysis may be high as 4–10%. The facial nerve paralysis may appear immediately or delayed after tympanomastoid surgery. There are different proposed causes such as trauma, neural devascularization, and viral reactivation. The inflammation and edema due to trauma will reach its maximum by 24–48 h after surgical manipulation and some cases of postoperative facial nerve paralysis have happened close to this time frame. The onset of the facial nerve paralysis may occur an average of 11 days after tympanomastoid surgery. Facial nerve damage by mastoid drilling, drill resulting in vibration-induced nerve injury is another possible traumatic etiology.
Late facial nerve paralysis after tympanomastoid surgery should be differentiated from iatrogenic facial nerve paralysis after otologic surgery. Iatrogenic facial nerve paralysis occur by direct injuries to the facial nerve at the time of the surgery. In this iatrogenic facial nerve injury, immediate exploration of the facial nerve is needed which includes facial nerve decompression, end-to-end anastomosis of the facial nerve, or nerve grafting may be required depending on the mechanism of the injury. However, the late facial nerve paralysis after tympanomastoid surgery in this study was treated conservatively. The incidence of the dehiscence of fallopian canal is high as 40%–74% of the temporal bones., One study reviewed 160 temporal bones from 129 individuals and documented dehiscence of the fallopian canal in 74% of them, the majority at the site of oval window with a length of 0.4–2.64 mm. Moreano et al. have studied 1000 temporal bones and documented 56% fallopian canal dehiscence with 76.3% prevalence of bilaterality. The incidence of multiple dehiscence along the fallopian canal in the temporal bone is higher in cases of specimens of newborns and young children. If the facial nerve is exposed and irritated by the heat energy through an electric drill or electrical coagulation, delayed facial nerve paralysis may occur.
In this study, 55.55% of the patients with late facial nerve paralysis had fallopian canal dehiscence and exposure of the facial nerve, whereas only 18.27% of the patients without late facial nerve paralysis had fallopian canal dehiscence (P < 0.01) represent that fallopian canal dehiscence was a risk factor late facial nerve paralysis after tympanomastoid surgery.
The incidence of late or delayed facial nerve paralysis after tympanomastoid surgery was 1.23% in our series (18 out of 1452 cases). There are 61.5–41 times of the estimated incidence (0.02–0.03%) of Bell's palsy.,
Tiny injuries to the chorda tympani nerve, for example, by stretching or retrograde facial nerve edema may be responsible for late facial nerve paralysis after stapedectomy surgery., In this study, chorda tympani nerve was injured in three cases (16.66%) and overstretched in three cases (16.66%) out of 18 cases showed late facial nerve paralysis. Hence, the otorhinolaryngologists should avoid amputation or overstretch of the chorda tympanic nerve during surgery, if possible, to prevent late facial nerve paralysis. The traumatic injury of the chorda tympani nerve may be lacerated, transected, or crushed, with resulting in intraneural hematoma or edema. The prognosis and the management vary as per the mechanism of the injury.
The activation of a latent virus after surgical procedure is not a new or uncommon. In 1905, Cushing was the first to report the reactivation of the latent herpes simplex virus (HSV) for performing the surgery on the trigeminal nerve. After surgical procedure on the trigeminal nerve, herpes labialis lesions and other mucocutaneous, or cutaneous lesions are frequently found along with the nerve's distribution. In relation to late facial nerve paralysis, the rates of the postoperative reactivation of the HSV are directly proportional to the severity of the neural manipulation during the surgical procedure. Viral reactivation may be a potential cause of late facial nerve paralysis after tympanomastoid surgery. One possible etiology for viral reactivation is the physical manipulation of the facial nerve or ganglion where the virus is dormant. Another possible etiology is reduced immunity or stress after surgery. One report documented that late or delayed facial nerve paralysis after tympanomastoid surgery was due to viral reactivation. In our study, out of 18 patients, there were two patients (11.11%) had herpes labialis where IgM antibody to varicella-zoster virus was detected in both patients which favor the viral etiology (Varicella-zoster virus) for delayed facial nerve paralysis after tympanomastoid surgery. One study used polymerase chain reaction technique to detect HSV-1 in saliva of the patients with late facial nerve paralysis after tympanomastoid surgery where four out of the five patients showed high titer HSV-1.,
The use of steroid and antiviral drugs is useful for the treatment of the delayed facial nerve paralysis due to viral reactivation. One study documented that the treatment with prednisone and acyclovir within 3 days of the onset of the facial nerve paralysis have a significant role for the treatment of delayed facial nerve paralysis due to viral reactivation and proved to be an effective treatment option which provided complete recovery of the facial nerve function., One report documented two cases of late facial nerve paralysis after tympanomastoid surgery, both of which completely recovered within 6 months. Another report documented about five cases of the late facial nerve paralysis those recovered completely., In our study, out of 18 patients, 12 recovered completely within 10 days, seven patients returned to normal level within 3 weeks and one patient backed to Grade-I by 6 weeks. In summary, the incidence of the delayed or late facial nerve paralysis following tympanomastoid surgery is low. It can occur after 3 days–2 weeks after the surgery.[25a] Dehiscence of fallopian canal is an important cause for this late-onset facial nerve palsy. The prognosis of the late facial nerve paralysis following tympanomastoid surgery appears to be good.
| Conclusion|| |
Facial nerve paralysis after ear surgery results in great psychological trauma among the patients. There are different causes for the development of the late facial nerve paralysis after tympanomastoid surgery. Late facial nerve paralysis after tympanomastoid surgery is often associated with dehiscence of the fallopian canal. The dehiscence of the fallopian canal should be considered an important risk factor during dealing with the patient of late/delayed facial nerve palsy after otological surgery. The outcomes of the patient with late facial nerve palsy after tympanomastoid surgery are often good without any complications.
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