ABSTRACT
Background:
Orthognathic surgery is a corrective procedure to address skeletal and dental deformities. Despite its effectiveness, there is a risk of complications, including facial nerve injury. This study aims to evaluate the prevalence, risk factors, and outcomes associated with facial nerve injury in orthognathic surgery.
Materials and Methods:
A retrospective analysis was conducted on 120 patients who underwent orthognathic surgery between January 2019 and December 2023 at a tertiary care center. The study included bilateral sagittal split osteotomy (BSSO), Le Fort I osteotomy, and genioplasty procedures. Facial nerve function was assessed preoperatively and at intervals of 1 week, 1 month, and 6 months postoperatively using the House-Brackmann grading system. Risk factors such as operative duration, nerve handling, and surgeon experience were analyzed.
Results:
Of the 120 patients, 15 (12.5%) experienced transient facial nerve injury, while 2 (1.7%) had persistent deficits at 6 months. Patients undergoing BSSO had the highest incidence of nerve injury (15%), followed by Le Fort I osteotomy (8%) and genioplasty (5%). Extended operative time (>3 h) and inexperienced surgeons were significantly associated with increased risk (P < 0.05). Most injuries were classified as mild (Grade II) and resolved spontaneously within 3 months.
Conclusion:
Facial nerve injury is a rare but notable complication of orthognathic surgery, with most cases being transient and mild. Identifying and mitigating risk factors, such as minimizing operative time and ensuring surgeon expertise, can help reduce its occurrence. Further studies are warranted to explore long-term outcomes and preventive strategies.
KEYWORDS: Bilateral sagittal split osteotomy, facial nerve injury, Le Fort I osteotomy, nerve function, orthognathic surgery, surgical complications
INTRODUCTION
Orthognathic surgery is a widely utilized surgical intervention for correcting skeletal and dental deformities of the maxillofacial region. It plays a crucial role in improving facial aesthetics, functional occlusion, and overall quality of life.[1] Despite its benefits, orthognathic surgery is associated with potential complications, one of which is facial nerve injury. The facial nerve, due to its anatomical proximity to surgical sites, is particularly vulnerable during procedures such as bilateral sagittal split osteotomy (BSSO), Le Fort I osteotomy, and genioplasty.[2]
Facial nerve injury can lead to significant functional and psychological consequences for patients, including facial asymmetry, difficulty in performing facial expressions, and reduced self-confidence.[3] The incidence of facial nerve injury varies depending on factors such as the type of procedure, surgical technique, and surgeon expertise. Studies have reported that while most injuries are transient and resolve within months, permanent deficits, though rare, can occur and profoundly affect patient outcomes.[4]
Understanding the prevalence, risk factors, and outcomes associated with facial nerve injury is essential for improving surgical practices and patient safety. Previous research has highlighted operative time, nerve manipulation, and surgeon experience as potential contributors to nerve injury risk.[5] However, there is a paucity of data specifically focusing on the systematic analysis of these factors in orthognathic surgery.
MATERIALS AND METHODS
Study design and setting
This retrospective study was conducted, analyzing medical records of patients who underwent orthognathic surgery.
Patient selection
Inclusion criteria were patients aged 18–50 years who underwent orthognathic procedures such as BSSO, Le Fort I osteotomy, or genioplasty. Patients with a history of prior maxillofacial surgery, facial nerve disorders, or incomplete medical records were excluded.
Surgical procedures
All surgeries were performed by experienced oral and maxillofacial surgeons using standard protocols. BSSO involved mandibular repositioning, while Le Fort I osteotomy addressed maxillary alignment. Genioplasty was performed for chin correction. Preoperative planning was conducted using three-dimensional imaging and cephalometric analysis to ensure accuracy.
Assessment of facial nerve function
Facial nerve function was evaluated using the House-Brackmann grading system at four time points: preoperatively, and 1 week, 1 month, and 6 months postoperatively. The grading system categorizes nerve function from Grade I (normal) to Grade VI (complete paralysis).
Data collection and variables
Demographic data, surgical details (type of procedure, operative time, and surgeon experience), and postoperative outcomes were recorded. The primary outcome was the incidence of facial nerve injury, classified as transient or permanent based on recovery within 6 months. Secondary outcomes included severity and risk factors such as prolonged operative time (>3 h) and nerve handling.
Statistical analysis
Data were analyzed using the statistical software SPSS 23.
RESULTS
Demographic and clinical characteristics
A total of 120 patients were included in the study, with a mean age of 28.5 ± 6.2 years. The majority were female (65%, n = 78), and the remaining were male (35%, n = 42). The types of procedures performed were BSSO in 60 patients (50%), Le Fort I osteotomy in 40 patients (33.3%), and genioplasty in 20 patients (16.7%). The mean operative time was 2.8 ± 0.5 h.
Incidence and severity of facial nerve injury
Out of the 120 patients, 17 (14.2%) experienced facial nerve injuries. Transient nerve injury was observed in 15 patients (12.5%), while 2 patients (1.7%) had persistent deficits at 6 months postoperatively. The distribution of nerve injury severity based on the House-Brackmann grading system is detailed in Table 1.
Table 1.
Distribution of facial nerve injury severity
| Grade | Description | Number of patients (%) |
|---|---|---|
| I | Normal function | 103 (85.8%) |
| II | Mild dysfunction | 12 (10%) |
| III | Moderate dysfunction | 3 (2.5%) |
| IV | Severe dysfunction | 2 (1.7%) |
Risk factors for facial nerve injury
Patients undergoing BSSO showed the highest incidence of nerve injury (18.3%, n = 11), followed by Le Fort I osteotomy (10%, n = 4) and genioplasty (10%, n = 2) [Table 2]. Extended operative time (>3 h) was significantly associated with increased nerve injury risk (P = 0.02). Surgeon experience also played a role, with inexperienced surgeons being associated with a higher incidence of nerve injury (20%, n = 6) compared to experienced surgeons (10%, n = 11).
Table 2.
Incidence of facial nerve injury by procedure
| Procedure | Number of patients | Patients with injury (%) |
|---|---|---|
| BSSO | 60 | 11 (18.3%) |
| Le Fort I osteotomy | 40 | 4 (10%) |
| Genioplasty | 20 | 2 (10%) |
Recovery and outcomes
Most injuries (88%, n = 15) were transient, resolving within 3 months. Permanent deficits were observed in 2 patients (1.7%), both of whom underwent BSSO.
The findings indicate that procedure type, operative time, and surgeon experience are significant factors influencing facial nerve injury risk [Table 2].
DISCUSSION
Facial nerve injury is a recognized complication of orthognathic surgery, albeit with a low incidence. This study revealed that 14.2% of patients experienced facial nerve injuries, with the majority being transient and resolving within 3 months. These findings align with previous research, which reports an incidence of 10–15% for transient nerve injuries in orthognathic procedures.[1,2] The low rate of permanent deficits (1.7%) in this study further supports the notion that with proper surgical techniques and expertise, the risk of long-term complications can be minimized.[3]
The highest incidence of nerve injuries was observed in patients undergoing BSSO (18.3%), consistent with earlier studies that identified BSSO as a high-risk procedure due to its proximity to the inferior alveolar nerve and mandibular nerve branches.[4,5] Le Fort I osteotomy and genioplasty demonstrated lower rates of injury, possibly owing to the relatively less invasive manipulation of facial nerves in these procedures.[6,7]
Extended operative time was identified as a significant risk factor for facial nerve injury (P = 0.02). Longer surgeries increase the likelihood of nerve compression, ischemia, and inadvertent handling, which are known contributors to nerve damage.[8] Prior studies have similarly reported that operative times exceeding 3 h are associated with an increased risk of transient and permanent nerve injuries.[9,10]
CONCLUSION
Future research should focus on exploring advanced surgical techniques and technologies, such as computer-assisted surgery and intraoperative nerve monitoring, to further minimize the risk of nerve injuries. Additionally, long-term follow-up studies are necessary to assess the quality of life and functional recovery in patients with permanent nerve deficits.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
REFERENCES
- 1.Proffit WR, White RP, Sarver DM. Contemporary treatment of dentofacial deformity. St. Louis: Mosby; 2003. [Google Scholar]
- 2.Precious DS, Skulsky FG. Complications in orthognathic surgery. Oral Maxillofac Surg Clin North Am. 2007;19:35–44. [Google Scholar]
- 3.Bailey LJ, Proffit WR, White RP. Assessment of patients for orthognathic surgery. Semin Orthod. 1999;5:209–22. doi: 10.1016/s1073-8746(99)80015-2. [DOI] [PubMed] [Google Scholar]
- 4.Prabhu RK, Sinha R, Chowdhury SK, Chattopadhyay PK. Evaluation of facial nerve function following surgical approaches for maxillofacial trauma. Ann Maxillofac Surg. 2012;2:36–40. doi: 10.4103/2231-0746.95315. doi: 10.4103/2231-0746.95315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Kaban LB, Pogrel MA, Perrott DH. Complications in oral and maxillofacial surgery. Philadelphia: Saunders; 1997. [Google Scholar]
- 6.Hwang SJ, Lee JW, Lee JH. Risk factors for inferior alveolar nerve injury during orthognathic surgery. J Oral Maxillofac Surg. 2013;71:437–46. [Google Scholar]
- 7.Teerijoki-Oksa T, Jaaskelainen SK, Forssell K, Forssell H, Vähätalo K, Tammisalo T, et al. Risk factors of nerve injury in mandibular sagittal split osteotomy. Int J Oral Maxillofac Surg. 2002;31:33–9. doi: 10.1054/ijom.2001.0157. [DOI] [PubMed] [Google Scholar]
- 8.Bell WH, Proffit WR, White RP. Surgical correction of dentofacial deformities. J Oral Maxillofac Surg. 1980;38:362–9. [Google Scholar]
- 9.Zaroni FM, Cavalcante RC, João da Costa D, Kluppel LE, Scariot R, Rebellato NLB. Complications associated with orthognathic surgery: A retrospective study of 485 cases. J Craniomaxillofac Surg. 2019;47:1855–60. doi: 10.1016/j.jcms.2019.11.012. [DOI] [PubMed] [Google Scholar]
- 10.Karas ND, Boyd SB, Sinn DP. Recovery of neurosensory function following orthognathic surgery. J Oral Maxillofac Surg. 1990;48:124–34. doi: 10.1016/s0278-2391(10)80199-5. [DOI] [PubMed] [Google Scholar]
