The transmandibular approach has been a cornerstone of open surgery for lesions of the oropharynx and parapharyngeal space. For decades, it provided access to anatomical regions that were difficult to reach.
Why divide the mandible?
The principal anatomical obstacle is the mandible itself. The oropharynx and parapharyngeal space lie medial to the mandibular ramus, which limits direct lateral access to deep lesions. Although a transcervical approach may provide adequate exposure for selected parapharyngeal tumours, access becomes increasingly difficult for large, high, medial or anteriorly extending lesions, as well as for tumours involving the oropharynx.
The transmandibular approach overcomes this barrier by temporarily opening the mandible, allowing the bone to be mobilised and the surgical field to be exposed directly. This provides a wide operative corridor, facilitates visualisation of the tumour and surrounding structures, and allows extensive resections and reconstruction when required.
Surgical technique
The procedure typically begins with a lower lip-splitting incision, continued through the soft tissues of the chin to provide access to the anterior mandible. Depending on the planned resection and the surgeon’s preference, the incision may be extended into a cervical incision to facilitate neck dissection and exposure of the major vessels.
After raising the appropriate soft-tissue flaps and exposing the mandible, a paramedial mandibulotomy is performed. The precise location and configuration of the osteotomy depend on the anatomy, dentition, planned resection and reconstructive strategy. The osteotomy must be carefully planned to preserve dental roots and the integrity of the remaining mandible. Pre-plating, with subsequent fixation using miniplates or other suitable osteosynthesis systems, may facilitate accurate restoration of mandibular alignment.
The mandibular segment can then be mobilised, creating direct access to the oropharynx and parapharyngeal space. The required tumour resection is performed under direct vision, with the extent of soft-tissue and bony removal determined by the lesion and oncological requirements. Reconstruction may involve local or regional flaps, free tissue transfer, or other techniques according to the resulting defect.
At the end of the procedure, the mandible is repositioned and rigidly fixed, the soft tissues are reconstructed, and the lip and facial incision are meticulously closed.
Consequences and functional morbidity
The transmandibular approach provides excellent exposure, but this comes at a cost. Its consequences extend beyond the immediate surgical wound and must be considered in relation to the individual procedure, the extent of resection and the reconstruction required.
Aesthetic consequences. Lip splitting and the external incision leave a visible facial scar. With careful incision placement and meticulous closure, the cosmetic result can be acceptable, but the scar remains a potential source of dissatisfaction. Lower lip asymmetry, changes in the vermilion border and injury to the marginal mandibular or other facial nerve branches may further affect appearance.
Functional consequences. These are often more important than the scar itself. Mandibulotomy introduces risks of malocclusion, delayed union or non-union, infection, hardware exposure and, in selected cases, dental injury or mandibular osteonecrosis. Trismus, pain and impaired mastication may occur, particularly when surgery involves the masticatory apparatus or requires extensive soft-tissue resection.
When the approach is used for oropharyngeal cancer, functional outcomes are also heavily influenced by the structures removed. Resection involving the tongue base, soft palate, pharyngeal constrictors or adjacent neurovascular structures can result in dysphagia, impaired speech, velopharyngeal insufficiency and aspiration. Extensive defects may require complex reconstruction and prolonged swallowing rehabilitation. These consequences cannot be attributed to the mandibulotomy alone, but the morbidity of the access procedure adds to that of the resection itself.
Is it still a good approach?
For many years, it was the best available option for obtaining adequate exposure of deep oropharyngeal lesions and selected parapharyngeal tumours. It remains valuable in carefully selected cases, particularly when extensive exposure is essential, the tumour cannot be safely or adequately removed through a less invasive route, or mandibular involvement requires an open resection.
However, the treatment landscape has changed substantially. For oropharyngeal cancer, transoral surgery, particularly transoral robotic surgery (TORS), offers an alternative for many appropriately selected patients. By approaching the tumour through the mouth, TORS avoids the need for a facial incision and mandibulotomy, potentially reducing access-related morbidity while providing adequate oncological resection in suitable cases.
This does not mean that transoral surgery can replace every open approach. Tumour extent, exposure, involvement of adjacent structures, resection margins, reconstructive requirements and the experience of the surgical team remain decisive factors. Large or infiltrative lesions and tumours extending beyond the limits of a safe transoral resection may still require an open approach.
The evolution from transmandibular access to transoral surgery illustrates a broader principle in Head&Neck oncology: the objective is not simply to obtain wider exposure, but to achieve adequate oncological resection with the least possible functional and aesthetic cost. The transmandibular approach retains an important place in the surgical armamentarium, but for most of the patients with oropharyngeal cancer, it is no longer the only way to reach the tumour.
J Granell. Oct 12, 2026