The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures

Abstract

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.

The condylar region is one of the most frequent sites of mandibular fracture, accounting for 9–50% of all such maxillofacial fractures. These fractures can occur as single unilateral or bilateral condylar fractures, and they may occur together with fractures of the mandibular symphysis or corpus, or with dentoalveolar injuries. The management of these fractures has long been controversial. Although closed treatment, such as maxillomandibular fixation (MMF), with early physical therapy has previously been the most widely used method, even for the treatment of dislocated condylar fractures, anatomical reduction can be difficult to achieve compared with that achievable by surgical open reduction and internal fixation (ORIF). Furthermore, consensus has recently been reached regarding the ORIF of condylar fractures: specifically, displaced bilateral fractures or severe unilateral displacement with dislocation in the condylar neck or subcondylar position (except in growing children) may be appropriate indications for ORIF. This is because better, quicker functional rehabilitation of the temporomandibular joint (TMJ) can be achieved with ORIF, and superior clinical functional results have been reported.

Various surgical techniques, approaches, and fixation methods have been described for ORIF of condylar process fractures, together with the establishment of stability using miniplate osteosynthetic fixation. Most surgeons prefer extraoral over intraoral approaches, because they provide good visualization and a better surgical field. However, extraoral approaches are associated with a risk of surgical complications, including pre-auricular, retromandibular, submandibular, and salivary fistulas, visible scars, and facial nerve damage or palsy (typically temporary), which may make surgeons hesitant to perform ORIF.

The retromandibular approach was first described by Hinds and Girotti in 1967 and modified by Koberg and Momma in 1978. Later, Ellis and Dean reported – based on modifications and accumulated case series reports – that the retromandibular transparotid approach could offer great advantages because of the shorter working distance from the facial skin incision to the condylar segment, better, quicker access to the posterior border of the mandible to the sigmoid notch, less conspicuous facial scarring, and an easier surgical process for reduction and fixation.

Since 2008, with reference to the categorization of Ellis, we have prospectively determined the surgical approach for ORIF surgery in patients presenting with condylar process fractures; results have been reported in a previous publication and the approaches are summarized in Fig. 1 . In brief, lower condylar process fractures, such as subcondyle fractures, have been treated surgically with an intraoral approach alone, using a small angulated screwdriver system without the assistance of an endoscope. For condylar neck fractures, displaced fractures have all been treated surgically with the retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates, as studied clinically here. Alternatively, for cases with non-displaced or non-deviated simple linear condylar neck fractures only, we have offered optional surgery involving endoscopically assisted (30°- and 45°-angled, 4-mm-diameter endoscopes; Karl Storz GmbH & Co. KG, Tuttlingen, Germany) transoral ORIF treatment using a small angulated screwdriver. Higher condylar process fractures, such as those of the condylar head, have been treated with a pre-auricular approach in some cases. Further, non-surgical treatments, such as closed treatment with MMF and early physical therapy, have been performed for fractures in cases with no functional disturbance, for non-displaced condylar fractures, in the majority of paediatric patients (<16 years), and in most condylar head and intracapsular fractures.

Fig. 1
Schematic diagram of our routine surgical access method for fractured condylar processes of the mandible, according to the categorization of Ellis.

Thus, this prospective clinical study was carried out in 19 patients to assess the clinical results in terms of the duration, efficacy, stability, and safety of the surgical treatment of displaced condylar neck fractures by open reduction and rigid internal fixation using two 2.0-mm locking miniplates via a retromandibular transparotid approach and to evaluate the morbidity and complications associated with the procedure with medium-term clinical follow-up at a single institution.

Patients and methods

Patients

This prospective study was conducted between January 2009 and August 2012. Nineteen consecutive patients with displaced condylar neck fractures were included in the study. They consisted of 16 males and three females, ranging in age from 17 to 87 (mean 43.1) years, all of whom responded to a follow-up call at least 6 months after the surgery.

As for non-displaced or non-deviated simple linear condylar neck fractures, we offered the optional surgical approach of endoscopically assisted transoral ORIF treatment, as mentioned above; seven other simple condylar neck fractures were treated with this method during the 3.7-year study period. Further, two comminuted fractures and one old condylar neck fracture were excluded from the study.

Types of fracture

Patient profiles, fracture side, deviation of the condylar segment according to the MacLennan classification (in which the cases are classified as deviation, displacement, and/or dislocation), additional mandibular and midfacial fractures, and the cause of trauma were analyzed further.

Thirteen patients had unilateral condylar neck fractures and six had bilateral condylar fractures, with condylar neck fractures on one side and subcondylar neck fractures on the other in three patients and condylar head fractures on the other in the remaining three patients ( Table 1 ).

Table 1
Description of the mandibular condylar neck fractures in the 19 patients.
Case No. Sex Age, years Type of fracture (side) Associated mandibular fractures Additional maxillofacial fractures Cause of trauma Operation time (min)
1 F 21 Rt, deviation Lt mandibular body Fall
2 M 71 Rt, deviation Slip down 40
3 M 22 Lt, deviation Sport 55
4 M 17 Rt, displacement Traffic accident 63
5 M 28 Rt, displacement Traffic accident 58
6 M 37 Rt, displacement Symphysis, Lt condylar head Traffic accident
7 M 49 Lt, displacement Traffic accident 50
8 M 87 Lt, displacement Rt subcondyle Slip down
9 M 27 Lt, displacement Symphysis, Rt condylar head Le Fort I Traffic accident
10 M 63 Lt, displacement Rt subcondyle Le Fort I/II Fall
11 M 52 Lt, displacement Symphysis Slip down
12 M 59 Rt, dislocation Lt mandibular angle Traffic accident
13 M 37 Rt, dislocation Symphysis Traffic accident
14 M 29 Lt, dislocation Symphysis, Rt subcondyle Traffic accident
15 M 65 Lt, dislocation Fall 42
16 M 31 Lt, dislocation Rt mandibular angle, Lt mandibular body Le Fort II/III Traffic accident
17 F 29 Lt, dislocation Rt mandibular angle Fall
18 M 43 Lt, dislocation Symphysis, Rt condylar head Traffic accident
19 F 51 Lt, dislocation Rt mandibular body Rt zygoma Traffic accident
43.1 51.3
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Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures
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