Skull Base 2008; 18(1): 009-015
DOI: 10.1055/s-2007-992764
ORIGINAL ARTICLE

© Thieme Medical Publishers

Anatomic Variations of the Sphenoid Sinus and Their Impact on Trans-sphenoid Pituitary Surgery

Ossama Hamid1 , Lobna El Fiky1 , Ossama Hassan1 , Ali Kotb2 , Sahar El Fiky3
  • 1Department of Otorhinolaryngology, Ain Shams University, Cairo, Egypt
  • 2Department of Neurosurgery, Ain Shams University, Cairo, Egypt
  • 3Department of Radiodiagnosis, Ain Shams University, Cairo, Egypt
Further Information

Publication History

Publication Date:
06 November 2007 (online)

ABSTRACT

Introduction: The trans-sphenoid access to the pituitary gland is becoming the most common approach for pituitary adenomas. Preoperative evaluation of the anatomy of the sphenoid sinus by computed tomography (CT) scan and magnetic resonance imaging (MRI) is a routine procedure and can direct the surgical decision. Purpose: This work determines the incidence of the different anatomical variations of the sphenoid sinus as detected by MRI and CT scan and their impact on the approach. Methods: The CT scan and MRI of 296 patients operated for pituitary adenomas via a trans-sphenoid approach were retrospectively reviewed regarding the different anatomical variations of the sphenoid sinus: degree of pneumatization, sellar configuration, septation pattern, and the intercarotid distance. Results: There were 6 cases with conchal pneumatization, 62 patients with presellar, 162 patients with sellar, and 66 patients with postsellar pneumatization. There was sellar bulge in 232 patients, whereas this bulge was absent in 64 patients. There was no intersphenoid sinus septum in 32 patients, a single intersphenoid septum in 212 patients, and an accessory septum in 32 patients. Intraoperatively, the sellar bulge was marked in 189 cases and was mild in 43 cases. Discussion: The pattern of pneumatization of the sphenoid sinus significantly affects the safe access to the sella. A highly pneumatized sphenoid sinus may distort the anatomic configuration, so in these cases it is extremely important to be aware of the midline when opening the sella to avoid accidental injury to the carotid and optic nerves. The sellar bulge is considered one of the most important surgical landmarks, facilitating the access to the sella. The surgical position of the patient is also a crucial point to avoid superior or posterior misdirection with resultant complications. It is wise to use extreme caution while removing the terminal septum. Conclusion: Different anatomical configurations of the sphenoid sinus can seriously affect the access to the sella via the nose. The surgeon should be aware of these findings preoperatively to reach the sella safely and effectively.

REFERENCES

  • 1 Cavallo L M, Messina A, Cappabianca P et al.. Endoscopic endonasal surgery of the midline skull base: anatomical study and clinical considerations.  Neurosurg Focus. 2005;  19 E2
  • 2 Hamberger C A, Hammer G, Norlen G. Transphenoidal hypophysectomy.  Arch Otolaryngol. 1961;  74 2-8
  • 3 Batra P S, Citardi M J, Gallivan R P, Roh H J, Lanza D C. Software-enabled computed tomography analysis of the carotid artery and sphenoid sinus pneumatization patterns.  Am J Rhinol. 2004;  18 203-208
  • 4 Scuderi A J, Harnsberger H R, Boyer R S. Pneumatization of the paranasal sinuses: normal features of importance to the accurate interpretation of CT scans and MR images.  AJR Am J Roentgenol. 1993;  160 1101-1104
  • 5 Romano A, Zuccarello M, Van Loveren H R, Keller J T. Expanding the boundaries of the trans-sphenoidal approach: a micro anatomic study.  Clin Anat. 2001;  14 1-9
  • 6 Massoud A F, Powell M, Williams R A, Hindmarsh P C, Brook C GD. Trans-sphenoidal surgery for pituitary tumors.  Arch Dis Child. 1997;  76 398-404
  • 7 Nomikos P, Fahlbusch R, Buchfelder M. Recent developments in trans-sphenoidal surgery of pituitary tumors.  Hormones. 2004;  3 85-91
  • 8 Sirikci A, Bayazit Y A, Bayram M, Mumbuc S, Gungor K, Kanlikama M. Variations of sphenoid and related structures.  Eur Radiol. 2000;  10 844-848
  • 9 Shah N J, Navnit M, Deopujari C HE, Mukerji S HS. Endoscopic pituitary surgery: a beginner's guide.  Indian J Otolaryngol H & N Surg. 2004;  56 71-78
  • 10 Liu S, Wang Z, Zhou B, Yang B, Fan E, Li Y. Related structures of the lateral sphenoid wall anatomy studies in CT and MRI. [in Chinese].  Lin Chuang Er Bi Yan Hou Ke Za Zhi. 2002;  16 407-409
  • 11 Banna M, Olutola P S. Patterns of pneumatization and septation of the sphenoidal sinus.  J Can Assoc Radiol. 1983;  34 291-293
  • 12 Szolar D, Preidler K, Ranner G et al.. The sphenoid sinus during childhood: establishment of normal developmental standards by MRI.  Surg Radiol Anat. 1994;  16 193-198
  • 13 Sethi D S, Stanley R E, Pillay P K. Endoscopic anatomy of the sphenoid sinus and sella turcica.  J Laryngol Otol. 1995;  109 951-955
  • 14 Sethi D S, Pillay P K. Endoscopic management of lesions of the sella turcica.  J Laryngol Otol. 1995;  109(10) 956-962
  • 15 Chatrah P, Nouraei S A, De Cordova J, Patel M, Saleh H A. Endonasal endoscopic approach to the petrous apex: an image-guided quantitative anatomical study.  Clin Otolaryngol. 2007;  32(4) 255-260
  • 16 Renn W H, Rhoton Jr A L. Microsurgical anatomy of the sellar region.  J Neurosurg. 1975;  43 288-298

Lobna El FikyM.D. 

Assistant Professor of ORL, Ain Shams University, 48 Ibn El Nafees Street

6th District, Madinet Nasr, 11371 Cairo, Egypt

Email: lfiky@entainshams.com