Efficacy of Retromandibular Transparotid Approach for the Management of Extracapsular Subcondylar Mandibular Fractures Using 2-mm Titanium Miniplates: A Prospective Clinical Study

Operator Experience and Fracture Location Affects the Rate of Facial Nerve Injury in Condylar Fractures: An Analysis of 89 Cases

PURPOSE

The purpose of this study was to measure the frequency and identify risk factors for facial nerve injury (FNI) in the open treatment of condylar neck and subcondylar fractures.

MATERIALS AND METHODS

A prospective cohort study was conducted over 5 years on patients who were treated surgically for mandibular condylar fractures using the retomandibular transparotid approach (RMTA). The primary result was FNI occurrence (yes/no). The predictor variables were demographic, fracture location, and pattern (dislocation, present or not), as well as surgeon experience. Post-treatment functional facial nerve changes were initially assessed in the operating room as the patient regained consciousness and documented thereafter within, the 1st and 3rd weeks, and 3rd and 6th months. Appropriate statistics were computed and, SPSS version 16 was used to analyze the data. χ² test and Fisher exact test were used to assess significance (P ≤ 0.05).

RESULTS

Eighty-nine patients with 102 condylar fractures (63 subcondylar and 26 condylar neck), with a mean age of 28.5±7.5 years and 91% men were evaluated. There were 15 subjects (16.8%) with FNI and among them 6 subjects had persistent facial weakness for 6-8 weeks that completely resolved within 3 months, with no permanent facial nerve paralysis. The marginal mandibular (n = 7), buccal (n = 6), and zygomatic (n = 2) were the facial nerve branches involved. Risk factors for FNI were operator' inexperience, fracture-dislocation, and condylar neck fracture to the site and location of the fracture. Multivariate logistic regression showed that the location of the fracture at neck level (0.030∗), fracture dislocation (<0.001∗), and operator's inexperience (0.003∗) were significant risk factors for postoperative facial nerve injury (P ≤ 0.05).

CONCLUSIONS

If conducted properly, the RMTA is a safe method for treating condylar fractures with rare major complications; however, fracture dislocation, fractured condylar neck, and operator' in-experience were significantly associated with increased risk of developing transient postoperative FNI.

An Anatomical Landmark for Retromandibular Transparotid Approach to Treat Subcondylar Fractures

ABSTRACT

Although the retromandibular transparotid approach (RTA) has been widely used to treat mandibular subcondyle fractures, the transient facial nerve injury (FNI) caused by this approach is not uncommon. The purpose of this paper was to present an anatomical landmark for RTA to treat subcondylar fractures, aiming to minimize FNI caused by the surgery. A total of 25 patients with subcondylar fractures but no FNI underwent RTA surgery. Intraoperatively, the plane of angulus oris was utilized as a reference to open the parotid and masseter tissues for exposing the fracture site. Postoperatively, FNI and other surgical complications were counted. The results showed that except for 2 cases of hematoma, no FNI or other complications occur. As a conclusion, utilization of plane of angulus oris as a reference for RTA to treat subcondylar fractures might make the surgery safer and less invasive.

Retromandibular transparotid approach for subcondylar mandibular fracture: A retrospective study

INTRODUCTION

The retromandibular transparotid approach provides the shortest and the most direct access to mandibular sub-condylar fractures. However, this approach is less preferred due to the fear of facial nerve injury. The aim of this study was to evaluate the safety and morbidity of the retromandibular transparotid approach for open reduction and internal fixation of sub-condylar mandibular fractures.

METHODS

A retrospective cohort study of 29 patients with 35 sub-condylar mandibular fractures who underwent open reduction and internal fixation through the retromandibular transparotid approach was conducted. The primary study variable was facial nerve palsy, whereas the secondary variables were infection, sialocele, salivary fistula, stability of the fractured segments, post-operative malocclusion, Frey's syndrome, and unesthetic scar. All patients were followed up for 6 months. Predictor variables included age, gender, side, location, displacement, etiology, concomitant maxillofacial fractures, and healing status. Fisher's exact test was calculated to find the association between primary variables and predictor variables.

RESULT

Out of 35 sub-condylar fractures (29 patients; 23 male, 6 female), four (11.42%) developed transient facial nerve palsy. Fractures at the condylar neck level (P = .045) and with displacement (P = .026) were significantly associated with the development of facial nerve palsy. Four patients (13.8%) developed slight malocclusion, two had surgical site infections, two developed sialoceles, and one had a salivary fistula.

CONCLUSION

The retromandibular transparotid approach is safe and effective with rare major complications in the management of sub-condylar fractures of the mandible. Condylar neck fractures and displaced fractured segments are associated with an increased risk of development of facial nerve palsy.

Does the Retromandibular Transparotid Approach Provide Quicker Access to Fracture of Mandibular Subcondyle Compared With the Retromandibular Transmasseteric Anterior Parotid Approach?

PURPOSE

Limited studies are available in the literature comparing various surgical approaches for the management of condylar fractures, and those comparing different types of retromandibular approaches are even fewer in number. This study aimed to compare the efficacy of 2 variants of the retromandibular approach-retromandibular transmasseteric anterior parotid (RMTMAP) and retromandibular transparotid (RMTP) in terms of exposure time, blood loss, facial nerve palsy, sialoceles or parotid fistula formation, infection, and esthetics of scar tissue.

PATIENTS AND METHODS

A randomized controlled trial was designed in patients with mandibular subcondylar fractures requiring operative intervention. Patients were randomized into 2 groups based on a computer-generated randomization table. Group A included 37 cases, treated with the RMTMAP approach, and group B included 38 cases treated with the RMTP approach. The primary outcome variable was exposure time. Secondary outcome variables were blood loss during exposure, complications like facial nerve palsy, sialocele formation, surgical site infection, and scar esthetics. All patients were followed for 3 months. Collected data were analyzed using the χ² and analysis of variance tests.

RESULTS

The mean exposure time for fractures treated with the RMTMAP approach and RMTP approach was 21.08 ± 9.18 and 13.57 ± 6.09, respectively (P < .05). The mean blood loss for RMTMAP and RMTP approach was 11.75 ± 5.11 and 9.9 ± 3.77 mL, respectively (P = .078). No facial nerve injury was seen in patients treated with the RMTMAP approach, whereas 3 (7.8%) patients in the RMTP group had transient facial nerve injury (P = .08).

CONCLUSIONS

This study concludes that the RMTP approach provides quicker access to the condyle as compared with the RMTMAP approach. However, the incidence of transient facial nerve injury was more in the RMTP approach. Except for reduced blood loss in the RMTP approach, all other parameters were comparable in both the approaches.

Comparative Evaluation of Clinical and Radiological Outcomes of Retromandibular Transparotid and Transoral Endoscopic-Assisted Approach for Surgical Management of Mandibular Subcondylar Fractures

Study Design

A prospective randomized comparative study was conducted to evaluate the clinical and radiological outcomes of the retromandibular transparotid (RMT) approach with endoscopic-assisted transoral (ENDO) approach used for open reduction and internal fixation (ORIF) of adult mandibular subcondylar fractures.

Objectives

To evaluate and compare the primary functional outcome using the Helkimo's dysfunction index, the surgical ease, the incidence of facial nerve weakness, the cosmetic outcomes and the number of complications following ORIF of mandibular subcodylar fractures using the RMT and ENDO approaches.

Methods

In this prospective study, 20 patients with unilateral/bilateral subcondylay fractures requiring ORIF were recruited between 2017 and 2018. Patients were randomly divided into RMT and ENDO group, 10 patients in each. Clinical and radiological assessment was done preoperatively and in postoperative period it was done at different intervals over the period of 6 months. The intraoperative parameter time taken during surgery was correlated for association with the time elasped since day of trauma and with the fracture severity. Similarly, the presence of multiple fractures of the mandible and postoperative occlusion were evaluated for the association.

Results

Comparable functional results were noted in both groups without any statistical significance. ORIF in ENDO group proved to be more time-consuming. For the RMT group, visible scars were rated best or close to best at the end of 6 months but a greater number of facial nerve injuries were reported in the RMT group.

Conclusions

Superiority of one approach over others cannot be established since the outcomes were not statistically different. However, the ENDO approach appears to be safer. Therefore, there is a need for the development of innovative armamentarium which would improve the dexterity and ease of the surgeon and hence the total time taken for this minimally invasive approach for the management of subcondylar fracture.

The Retromandibular Transparotid Approach for Reduction and Internal Fixation of Mandibular Condylar Fractures

Introduction:

The retromandibular transparotid approach is most useful for condylar and subcondylar fractures and provides the best access to the joint and ascending ramus. The study aims at evaluating the ease of access and outcomes encountered on using the retromandibular transparotid approach to access the fracture site for the open reduction and internal fixation (ORIF) of condylar and sub-condylar fractures.

Materials and Methods:

An observational clinical study was carried out among 10 patients with unilateral and bilateral condylar fracture requiring ORIF. Maximal interincisal mouth opening, facial swelling, occlusal discrepancy, facial nerve injury, scar formation, and acceptability and complications including wound dehiscence, infection, and sialocele/salivary fistula were assessed and measured preoperatively and postoperatively.

Results:

There was a notable improvement in mouth opening and facial nerve weakness. Postoperative intermaxillary fixation was done with selective patients who had a discrepancy in their occlusion. Preoperatively, swelling was present in four patients (40%) out of 10 patients studied. There was no incidence of sialocele/salivary fistula in any of the cases studied.

Conclusion:

Retromandibular transparotid incision is technique sensitive and thorough knowledge about the retromandibular area is must for good results and minimal morbidity. The cosmetic results are good in this approach, as well as the facial nerve injury were less in this without any permanent damages.

Transmasseteric Anterior Parotid Approach for Treatment of Mandibular Subcondylar Fractures

This study demonstrated the application of transmasseteric anterior parotid approach for open reduction of mandibular subcondylar fractures depending on the basis of the anatomical study of the temporomandibular joint and parotid gland area. The anatomical study was performed on 5 Chinese adult cadavers fixed by 10% formalin. The temporomandibular joints and parotid regions were studied. In the clinical study, 26 patients with mandibular subcondylar fractures were recruited between July 2014 and December 2017. All 26 patients with mandibular subcondylar fractures received satisfactory occlusions and normal mouth opening: no postoperative facial paralysis occurred in these patients. It is crucial to know the anatomy of both temporomandibular joint and parotid region for reducing significantly the surgical trauma and complications. Transmasseteric anterior parotid approach is a feasible approach for the surgical treatment of the mandibular subcondylar fractures. This method can provide adequate exposure, minimal facial nerve injury, open reduction easily, and inconspicuous scarring.

Treatment of intractable parotid sialocele occurred after open reduction-fixation of mandibular subcondylar fracture

A sialocele is a subcutaneous cavity containing saliva, most often caused by facial trauma or iatrogenic complications. In subcondylar fractures, most surgeons are conscious of facial nerve injury; however, they usually pay little attention to the parotid duct injury. We report the case of a 41-year-old man with a sialocele, approximately 5×3 cm in size, which developed 1 week after subcondylar fracture reduction. The sialocele became progressively enlarged despite conservative management. Computed tomography showed a thin-walled cyst between the body and tail of the parotid gland. Fluid leakage outside the cyst was noted where the skin was thin. Sialography showed a cutting edge of the inferior interlobular major duct before forming the common major duct that seemed to be injured during the subcondylar fracture reduction process. We decided on prompt surgical treatment, and the sialocele was completely excised. A duct from the parotid tail, secreting salivary secretion into the cyst, was ligated. Botulinum toxin was administrated to block the salivary secretion and preventing recurrence. Treatment was successful. In addition, we found that parotid major ducts are enveloped by the deep lobe and extensive dissection during the subcondylar fracture reduction may cause parotid major duct injury.

Does encountering the facial nerve during surgical management of mandibular condylar process fractures increase the risk of facial nerve weakness? A systematic review and meta-regression analysis

PURPOSE

The purpose of this study was to identify whether the incidence of systematically identified or incidentally encountered facial nerve branches during dissection to approach condylar fractures increases risk of transient and/or permanent facial nerve weakness.

METHODS

A systematic review and meta-analysis were performed that included several databases with specific keywords, a reference search, and a manual search for suitable articles. The inclusion criteria were all clinical trials, with the aim of assessing the rate of facial nerve injuries when open reduction and internal fixation (ORIF) of condylar process fractures was performed using different surgical approaches. The articles had to have documented the number of encountered facial nerve branches during ORIF. The main outcome variable was transient and permanent facial nerve injury. The dependent variable was the event and/or number of encountered facial nerve branches during surgery, and how they were handled (i.e. dissected, retracted, etc.).

RESULTS

A total of 1202 mandibular condylar fractures were enrolled in 29 studies. Rate of transient facial nerve injury (TFNI) was 11.3 % (136/1202). The number of facial nerve branches encountered intraoperatively was 543, namely buccal, marginal mandibular, zygomatic and temporal nerve branches. There was a significant correlation suggesting that there is a strong positive linear relationship between TFNI and encountered facial nerve branches (Coef = 0.1916, P = 0.001). There was no significant relationship between permanent facial nerve injury and encountered facial nerve branches (P = 0.808). TFNI was 4.3% and 18.7% for those studies expressly reporting that facial nerve branches were encountered incidentally without dissection and with dissection, respectively. For studies reporting deliberate and systematic facial nerve dissection, TFNI was 20.9%. Finally, studies that did not report any encounters of facial nerve branches, TFNI was 7.9 %.

CONCLUSION

This meta-analysis demonstrated that manipulation of the facial nerve during different surgical approaches causes different incidences of facial nerve injury. The choice of surgical approach for a given fracture should take this into consideration.