Definition & Overview
A pterygomaxillary fossa surgery is a medical procedure performed on the pterygomaxillary fossa, which refers to a depression on both sides of the skull. The area is connected to the infratemporal region by the pterygomaxillary fissure.
Surgery performed in this area is usually due to lesions or tumours. The area is quite complex in structure. Thus, different approaches are used in performing the procedure, which is categorised under craniomaxillofacial surgery.
Who Should Undergo and Expected Results
A pterygomaxillary fossa surgery can be recommended for patients who have been diagnosed with a lesion or tumour in the said area. These tumours can be either benign or malignant. Tumours on the pterygomaxillary fossa typically originate from the soft tissues in the region, including the muscles, nerves, blood vessels, and bones. Due to the complexity of the area, tumours are not easily detected. The area is quite closely connected to the intracranial structures and the paranasal sinuses. Thus, they are only diagnosed when symptoms begin to arise. Even so, the symptoms are sometimes mistakenly attributed to other reasons.
Symptoms of tumours in the pterygomaxillary fossa include:
- Eustachian tube dysfunction
- Trismus, or spasm of the jaw muscles
- Cranial neuropathy
In addition to tumours, pterygomaxillary fossa surgery is also performed on patients who suffer from:
- Vasomotor rhinitis
- Sphenopalatine neuralgia
Pterygomaxillary fossa surgery also becomes necessary when a patient needs pterygomaxillary implants. These screw-type implants can fix a deficient maxillary bone without the need for a graft. They are helpful for patients who suffer from either partial or complete edentulism.
The complex area also makes surgery a challenge. Thus, pterygomaxillary fossa surgery is performed with careful planning and a combination of different approaches. Nowadays, one of these approaches is the endoscopic technique, which is more appropriate for palliative cases.
Pterygomaxillary fossa surgery is not recommended for everyone. Some patients who are considered not good candidates for the procedure include those with:
- Lymphoreticular tumours
- Pulmonary issues
- Cardiac problems
- Renal issues
- Disseminated disease
- Significant co-morbidities
The goal of the procedure is to excise the entire tumour. After the surgery, patients may need to undergo further cancer treatment depending on:
- Whether the tumour is malignant or benign
- The stage of the tumour, if it is found to be malignant
The success of the procedure is largely dependent on the size and location of the tumour and its proximity to the neurovascular structures in the area.
How is the Procedure Performed?
Not all pterygomaxillary fossa surgeries are performed in the same way. Researchers are developing more approaches due to the limited access to the surgical area that most existing techniques offer. Newer approaches are geared towards providing a wider field exposure of the pterygomaxillary fossa.
There is a new surgical approach used to remove most extensive tumours in the area. The surgery is performed through the following steps:
- The patient is placed under anaesthesia.
- The surgeon makes the first incision, dividing the upper lip in the midline. The incision passes through the nasal pyramid and continues in a lateral direction towards the temporomandibular joint.
- The surgeon makes another incision along the maxillary buccogingival fold. It runs from the midline to the retromolar area.
- The surgeon makes another incision that runs from the canine to the retromolar area.
- The surgeon then accesses and exposes the craniofacial skeleton before performing a frontotemporal craniotomy.
- The tumour is then exposed and resected.
- All structures are replaced, and the incisions are closed.
In another approach, the surgeon performs the following steps:
- The surgeon makes a transcervical incision combined with double osteotomies of the mandible.
- This allows the ascending ramus, the masseter muscle, and the overlying skin to reflect laterally.
- This gives the surgeon excellent access to the pterygomaxillary fossa and the base of the skull so the tumour can be removed more efficiently.
- Once the tumour is removed, the surgeon puts the ramus of the mandible back in place and fixes it with arch bars and interosseous wiring.
Possible Risks and Complications
Patients who undergo a pterygomaxillary fossa surgery face the usual risks associated with surgery. These include:
- Allergic reaction to the anaesthesia
They are also at risk of other potential complications caused by the complexity of the pterygomaxillary region. These include:
- Nerve or blood vessel damage
- Damage to other nearby structures
- Post-operative sinusitis
Despite these risks, the results of most pterygomaxillary fossa surgical procedures have been excellent, and these minor complications occur very rarely.
Jian XC, Liu JP. “A new surgical approach to extensive tumors in the pterygomaxillary fossa and the skull base.” Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003 Feb; 95(2): 156-62. http://www.ncbi.nlm.nih.gov/pubmed/12582354
Attia EL, Bentley KC, Head T, Mulder D. “A new external approach to the pterygomaxillary fossa and parapharyngeal space.” Head & Neck. 1984 Mar/Apr. 6(4): 884-891. http://onlinelibrary.wiley.com/doi/10.1002/hed.2890060414/full