Management of parapharyngeal-space tumors

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base

Purpose

Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application.

Methods

Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS.

Results

The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery.

Conclusions

Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

Primary parapharyngeal tumours: a review of 21 cases

BACKGROUND

The diagnostic and therapeutic procedures performed in a series of patients with primary parapharyngeal space (PPS) tumours treated at the ENT Departments of San Giovanni Bosco Hospital, Turin, and of the Pugliese-Ciaccio Hospital, Catanzaro, Italy, in the period 2001-2010 are evaluated.

MATERIALS AND METHODS

The retrospective review included 20 patients, 11 male and 9 female, average age of 41 years operated on for 21 primary PPS tumours. The most common tumours found were neurogenic neoplasms, while those of salivary origin were the next most common.

RESULTS

There were 14 paragangliomas (7 originating from carotid glomus, 5 from vagal and 2 from tympanicum), 1 sympathetic chain schwannoma and 6 pleomorphic adenomas. All the tumours were benign in nature and gave rise to few signs or symptoms. Patients underwent preoperative computed tomography (CT) scan or magnetic resonance imaging (MRI) or both. Most contrast-enhanced masses were submitted to some type of angiography. Most of the surgeries were planned through imaging alone, as preoperative fine needle aspiration (FNA) biopsy was performed only in six cases. Four different approaches were adopted for tumour removal: transcervical, transcervical/transparotid, cervical-transparotid-transmandibular and infratemporal fossa approach. There was no operative mortality, though neurologic morbidity was significant. Follow-up, extended to a maximum of 11 years, did not reveal any recurrences. In conclusion, neurogenic tumours may be the most common of PPS masses. Surgery is the mainstay treatment and external approaches offer the potential for satisfactory tumour resection. Of such external approaches, transcervical and cervical/transparotid are the most often used in benign forms.

CONCLUSION

The number of perioperative complications encountered in this series confirms the difficulty of performing surgery in this complex area, even in benign cases. The chances of avoiding vascular damage and saving the trunks or most of the nerve fibres involved depend not only on the skill and experience of the surgeon but also on the anatomy of the lesion, the type of connection between the tumour and the nerve from which it originates and the distribution of neural fibres in or around the tumour mass.