Evaluation of Preauricular Retromandibular Anteroparotid Versus Retromandibular Through Parotid Approach

Evaluation of Preauricular Retromandibular Anteroparotid Versus Retromandibular Through Parotid Approach

A Comparative Study Between Preauricular Retromandibular Anteroparotid Approach and Retromandibular Transparotid Approach in Internal Fixation of Subcondylar Fracture on Facial Nerve Injury and Parotid Fistula

Of all the bones in the maxillofacial area, the condylar process is the most susceptible to fracture. The incidence of condylar fracture accounts for 25% to 50% of all mandibular fractures. Though remained controversial for a long time, surgical treatment of displaced subcondylar fractures appears today as the gold standard. Although there is a developing preference for open reduction and internal fixation of mandibular condylar fractures, the optimal approach to the ramus condylar unit remains controversial. Various approaches have been proposed, and each has specific shortcomings and disadvantages. Retromandibular, submandibular, transoral, and through parotid approaches are generally performed and sometimes used with an endoscope. Limited access and injury to the facial nerve are the most common problems, while Wilson introduced a new through masseter anteroparotid approach, this technique offers excellent access to the ramus condylar unit, and facial nerve damage risk is reduced.

Fractures of the mandibular condylar process have been documented to be one of the most common occurring mandibular fractures. When open treatment is selected, several surgical approaches can be used to expose, reduce, and stabilize the fracture site, each with its own set of advantages and disadvantages. Surgical approaches to the fractured mandibular condyle are broadly classified into intraoral and extraoral approaches. Intraoral approaches can be performed with or without endoscopic assistance. The most common extraoral approaches are submandibular, Risdon, preauricular, retroauricular, and retromandibular through parotid or through masseter approaches. An intraoral approach is time consuming and requires special instruments such as an endoscope, and additional training. Furthermore, cases of high fractures and/or medially displaced condylar fractures are technically difficult to manage through an intraoral approach, incorrect anatomical reduction, condylar head resorption, myofascial pain, and malocclusions have been reported to be more common complications following the intraoral approach when compared to extraoral approaches. In contrast, extraoral approaches are commonly used because they produce better visualization of the fracture site and therefore facilitate fracture reduction and fixation. However, extraoral approaches are complicated by the risk of injury to the facial, great auricular, and auriculotemporal nerves, visible scars, sialoceles, Frey syndrome and salivary fistulas.

Block, consecutive, 1:1 Consecutive because patients with subcondylar fracture need immediate surgical intervention, that is why investigators can not wait to collect the whole sample size and make computer generated randomization .

A preauricular incision will be made that extends downwards in a curvilinear fashion in the cervicomastoid skin crease, though any variation in this incision will suffice. The great auricular nerve will be preserved and the flap raised in the subdermal fat plane, superficial to the superficial musculoaponeurotic layer to allow access to the masseter adjacent to the anteroinferior edge of the parotid gland, just below the parotid duct. Branches of the facial nerve will be readily identified and avoided with or without loupe magnification, on the surface of the masseter muscle.

The incision for the retromandibular approach begins 5mm below ear lobe and continues 3 to 3.5cm inferiorly. Initial incision begins through skin and subcutaneous tissues,platysma muscle ,(SMAS), parotid capsule Dissection is continued until the only tissue remaining on the posterior border of the mandible will be the periosteum of pterygomassetric sling,then the fracture site will exposed and reduced.

Regarding facial nerve injury the measuring device is House- brachmann facial nerve grading system (HBFNGS) while the measuring unit is numerical from (I-VI) I= Normal, II= Mild dysfunction, III= Moderate dysfunction, IV= Moderately severe dysfunction, V= Severe dysfunction, VI= Total paralysis. I= Better while VI= Worse

Regarding salivary fistula the measuring device is clinical examination while the measuring unit is binary question.

The character of any observed scar was scored as (1) no perceptible scar, (2) visible but thin and linear scar, (3) wide scar, and (4) hypertrophic scar or keloid. while the measuring unit is numerical from (1-4) 1= Better while 4= Worse

Inclusion Criteria: Patients age should be more than 18 year. Patients with subcondylar fracture and need to open reduction and internal fixation using titanium miniplates. Patients should be free from any traumatic injuries to facial nerve or parotid gland. Availability of preoperative and postoperative panoramic radiographs and/or computed tomography (CT) images. Mental status permitting an adequate neuromotor examination. Regular clinical follow-up, documented in our clinical and radiographic evaluation charts, at 1 week, 1 month, 3 months and 6 months postoperatively Exclusion Criteria: Intraoral treatment of subcondylar fracture. Incooperative patients.

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