Endoscopic Transnasal Anatomy of the Infratemporal Fossa and Upper Parapharyngeal Regions: Correlations with Traditional Perspectives and Surgical Implications

Abstract

Background: The aim of this study was to illustrate the endoscopic surgical anatomy of the infratemporal fossa (ITF) and upper parapharyngeal space and to provide useful landmarks by comparing transnasal perspectives with external ones.

Materials and Methods: 6 fresh double injected heads were dissected. External lateral dissection was performed through a pre-auricular skin incision while external anterior dissection started with a modified Weber-Ferguson incision. External medial to lateral dissection was performed starting from the rhinopharyngeal and pterygoid regions, after cutting the specimen in 2 halves passing through the nose. Endoscopic dissection was performed through an endonasal approach (0° and 45° scopes).

Results: Among all the structures identified during the dissection, the most useful landmark when dissecting the ITF in a lateral to medial direction is the lateral pterygoid muscle. In anterior approaches (mostly endoscopic) the role of the lateral pterygoid muscle is less important and the Eustachian tube (ET) represents the most important landmark to point out the upper portion of the parapharyngeal internal carotid artery (ICA). The role of the ET, in lateral dissection is, on the contrary, by far less important given the fact that it is very deep in the surgical field and that the ICA is encountered earlier during surgical approaches. Another crucial landmark during anterior endoscopic surgery is the vidian nerve because it points to the anterior genu of the internal carotid artery.

Conclusion: The complex 3-dimensionality of the ITF and the upper parapharyngeal space needs a sound knowledge of the surgical anatomy. The role of the same landmarks changed in different approaches. The ability to orientate oneself in this complex area is related to an accurate knowledge of its anatomy through comparison of endoscopic and external perspectives.

Key words

infratemporal fossa - endoscopy

References

• 1 Conley JJ. The surgical approach to the pterygoid area.  Ann Surg. 1956;  144 39-43
• 2 Barbosa FJ. Surgery of extensive cancer of paranasal sinuses.  Arch Otolaryngol. 1961;  73 129-133
• 3 Isolan GR, Rowe R, Al-Mefty O. Microanatomy and surgical approaches to the infratemporal fossa: an anaglyphic 3-dimensional stereoscopic printing study.  Skull Base. 2007;  17 285-302
• 4 Kassam AB, Prevedello DM, Carrau RL. et al . The front door to Meckel's cave: an anteromedial corridor via expanded endoscopic endonasal approach-technical considerations and clinical series.  Neurosurgery. 2009;  64 (3 Suppl) 71-82
• 5 Vescan AD, Snyderman CH, Carrau RL. et al . Vidian canal: analysis and relationship to the internal carotid artery.  Laryngoscope. 2007;  117 1338-1342
• 6 Kassam AB, Vescan AD, Carrau RL. et al . Expanded endonasal approach: Vidian canal as a landmark to the petrous internal carotid artery.  J Neurosurg. 2008;  108 177-183
• 7 Kassam AB, Gardner P, Snyderman C. et al . Expanded endonasal approach: a fully endoscopic, completely transnasal approach to the middle third of clivus, petrous bone, middle cranial fossa and infratemporal fossa.  Neurosurg Focus. 2005;  19 E6
• 8 Herzallah IR, Germani R, Casiano RR. Endoscopic transnasal study of the infratemporal fossa: A new orientation.  Otolaryngol Head Neck Surg. 2009;  140 861-865
• 9 Robinson S, Patel N, Wormald PJ. Endoscopic management of benign tumors extending into the infratemporal fossa: a 2-surgeon transnasal approach.  Laryngoscope. 2005;  115 1818-1822
• 10 Gupta AK, Rajiniganth MG, Gupta AK. Endoscopic approach to juvenile nasopharyngeal angiofibroma: our experience at a tertiary care center.  J Laryngol Otol. 2008;  122 1185-1189
• 11 Castelnuovo P, Dallan I, Bignami M. et al . Nasopharyngeal endoscopic resection in the management of selected malignancies: 10-year experience.  Rhinology. 2009;  (accepted for publication)
• 12 Anand V. Infratemporal approaches for skull base lesions.  Oper Tech Neurosurg. 1999;  2 87-104
• 13 Sabit I, Schaefer SD, Couldwel WT. Modified infratemporal fossa approach via lateral transantral maxillotomy: A microsurgical model.  Surg Neurol. 2001;  58 21-31
• 14 Mansour OI, Carrau RL, Snyderman CH. et al . Preauricolar infratemporal fossa surgical approach: modifications of the technique and surgical indications.  Skull Base. 2004;  14 143-151
• 15 Carrillo JF, Rivas Leon B, Celis MA. et al . Anterolateral and lateral skull base approaches for treatment of neoplastic diseases.  Am J Otolaryngol. 2004;  25 58-67
• 16 Fisch U, Fagan P, Valvanavis A. The infratemporal fossa approach for the lateral skull base.  Otolaryngol Clin North Am. 1984;  17 513-552
• 17 Sekhar LN, Schramm  VL, Jones NF. Subtemporal pre-auricolar infratemporal fossa approach to large lateral and posterior cranial base neoplasms.  J Neurosurg. 1987;  67 488-499
• 18 Janecka IP, Sen CN, Sekhar LN. et al . Facial Translocation: A new approach to the cranial base.  Otolaryngol Head Neck Surg. 1990;  103 413-419
• 19 Terasaka S, Sawamura Y, Fukushima T. A lateral transzygomatic-transtemporal approach to the infratemporal fossa: Technical note for mobilization of the second and the third branches of the trigeminal nerve.  Skull Base. 1999;  9 277-287
• 20 Aslan A, Balyan FR, Taibah A. et al . Anatomic relationships between surgical landmarks in type B and type C infratemporal fossa approaches.  Eur Arch Otorhinolaryngol. 1998;  255 259-264

Correspondence