Endonasal Access to the Upper Cervical Spine: Part 2—Cadaveric Analysis

Abstract

Objectives The study aims to determine factors that augment endonasal exposure of the cervical spine.

Setting We used fluoroscopy and endoscopy to study endonasal visualization of the upper cervical spine.

Participants Ten cadavers with normal anatomy were studied.

Main Outcome Measures Endoscopic visualization was simulated with projected lines from an endoscope to the cervical spine in multiple positions.

Results Neck position alone did not affect the extent of endonasal exposure of the upper cervical spine, although there was a trend correlating the extended neck position with more caudal exposure. The greatest impact was with concurrent use of a 30-degree endoscope and neck extension, and more caudal access was achieved by tilting the endoscope against the piriform aperture, using the posterior tip of the hard palate as the fulcrum.

Conclusions Concurrent use of a 30-degree endoscope and neck extension increased the degree of exposure down the cervical spine. Maximum endonasal exposure of the upper cervical spine was obtained by maneuvering instruments at the fulcrum of the posterior hard palate and the nares, rather than changing the position of the neck alone. These results complement radiographic morphometric data in Part 1 of this study for preoperative assessment and surgical planning.

Keywords

cervical spine - endoscopic - minimally invasive - morphometric - odontoidectomy - endonasal

• References

• 1 Nayak JV, Gardner PA, Vescan AD, Carrau RL, Kassam AB, Snyderman CH. Experience with the expanded endonasal approach for resection of the odontoid process in rheumatoid disease. Am J Rhinol 2007; 21 (5) 601-606
• 2 Kassam AB, Snyderman C, Gardner P, Carrau R, Spiro R. The expanded endonasal approach: a fully endoscopic transnasal approach and resection of the odontoid process: technical case report. Neurosurgery 2005; 57 (1, Suppl): E213 , discussion E213
• 3 Alfieri A, Jho HD, Tschabitscher M. Endoscopic endonasal approach to the ventral cranio-cervical junction: anatomical study. Acta Neurochir (Wien) 2002; 144 (3) 219-225 , discussion 225
• 4 Messina A, Bruno MC, Decq P , et al. Pure endoscopic endonasal odontoidectomy: anatomical study. Neurosurg Rev 2007; 30 (3) 189-194 , discussion 194
• 5 Wu JC, Huang WC, Cheng H , et al. Endoscopic transnasal transclival odontoidectomy: a new approach to decompression: technical case report. Neurosurgery 2008; 63 (1) (Suppl. 01) ONSE92-4 , discussion E94
• 6 Baird CJ, Conway JE, Sciubba DM, Prevedello DM, Quiñones-Hinojosa A, Kassam AB. Radiographic and anatomic basis of endoscopic anterior craniocervical decompression: a comparison of endonasal, transoral, and transcervical approaches. Neurosurgery 2009; 65 (6, Suppl): 158-163 , discussion 63–64
• 7 de Almeida JR, Zanation AM, Snyderman CH , et al. Defining the nasopalatine line: the limit for endonasal surgery of the spine. Laryngoscope 2009; 119 (2) 239-244
• 8 Singh H, Grobelny BT, Harrop J, Rosen M, Lober RM, Evans J. Endonasal access to the upper cervical spine, part one: Radiographic morphometric analysis. J Neurol Surg B Skull Base 2013; 74 (3) 176-184