The Double Mandibular Osteotomy for Vascular and Tumor Surgery of the Parapharyngeal Space

Statement of the Problem: Access to the parapharyngeal space is the primary difficulty when dealing with tumors of this space or high internal carotid (Level III) lesions. Despite multiple publications describing the double mandibular osteotomy or similar procedures for parapharyngeal space access, there has been no comprehensive review of patient data in a retrospective fashion that describes the success rate and complications in a cohort of patients treated for both tumor and vascular pathologies.   To our knowledge, our report is the largest and most comprehensive series of patients treated with a double mandibulotomy for parapharyngeal space access in the English-language literature. 

The purpose of this study is to perform a review of all double mandibular osteotomy (DMO) cases used for tumor or vascular access performed at the University of Tennessee Medical Center (UTMC) and to determine the success of this procedure.  We aim to determine the rate of complications and outcomes for this cohort of patients.  We also plan to review the demographic data and medical comorbidities present at time of surgery for this cohort.

Methods: The investigators designed and implemented a retrospective chart review of medical records with a procedure code corresponding to a double mandibular osteotomy at UTMC from July 1, 2000 through March 1, 2016. After reviewing the case for inclusion in the study, the date of procedure, indication, age, gender, tobacco use, site of procedure, diagnosis of diabetes, diagnosis of cerebrovascular accident, diagnosis of transient ischemic attack, American Society of Anesthesiology physical status classification, intraoperative blood loss, days on ventilator post-operatively, and length of survival from time of procedure were recorded. Additionally, post-operative complications such as stroke, myocardial infarction, need for tracheostomy, malocclusion, mandible fracture, hardware failure, and wound dehiscence were recorded. 

The specific variation of double mandibular osteotomy utilized in our patient cohort combined a transcervical incision with vertical osteotomy anterior to the mental foramen and ipsilateral to the pathologic lesion with a vertical, posteriorly directed ramus osteotomy and rigid internal fixation. This allowed sufficient bone for fixation and avoided transection of the inferior alveolar nerve. No lip splitting incision or routine arch bar placement was utilized.

Results: During the study period, 16 patients underwent a double mandibular osteotomy procedure for access to the parapharyngeal space. In all cases, the procedure was completed as planned and access to the parapharyngeal space adequate. No cases were aborted due to inadequate access.  One patient developed osteomyelitis at an osteotomy site and one patient complained of post-operative malocclusion.  All cases resulted in radiographic bony union of the osteotomy segments and there were no cases of devascularization or devitilization of the osteotomy segment or teeth within the segments. One patient suffered a post-operative cerebrovascular accident with resulting dysphagia and need for long term feeding access. One patient developed first-bite syndrome during the post-operative period and this resolved without intervention.

Conclusion:  The described variation of the double mandibular osteotomy for access to the parapharyngeal space when performing tumor extirpation or vascular surgical interventions is a highly successful procedure with minimal morbidity. Clinicians should consider use of the double mandibular osteotomy when access to a parapharyngeal space tumor or distal carotid lesion is necessary.

 References:

1. Attia EL, Bentley KC, Head T, et al: A new external approach of the pterygomaxillary fossa and parapharyngeal space. Head Neck Surg 6:884, 1984
2. Valentini V, Fabiani F, Nicolai G, Torroni A, Battisti A, Iannetti G, Irace L, Faccenna F, Siani A, Pascucci M, Valentini FB. Surgical approach to the third area of the internal carotid artery through vertical osteotomy of the mandibular ramus: case report. J Craniofac Surg. Nov;13(6):816-20, 2002.