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

Department of Otorhinolaryngology, Ain Shams University, Cairo, Egypt.
Skull Base Surgery (Impact Factor: 0.6). 02/2008; 18(1):9-15. DOI: 10.1055/s-2007-992764
Source: PubMed


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.

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    • "Leng et al., (18) found also that CSF rhinorrhea might be attributed to excessive dissection at the nasal floor, widening the osteo-dural opening and surgery beyond the sella confines and those were in agreement with our findings. In this study, CT and MRI images of all cases were retrospectively evaluated, CT with image reconstruction was considered the basic investigation for evaluation of extended sphenoid sinus pneumatization through the surrounding bones, whereas MRI was reliable in the evaluation of perisphenoidal tumor extension/infiltration through the perisellar region and this was in agreement with Osama et al., (26). In our study, sellar type (85.7%) was the most frequent type of pneumatization and this was the same finding in multiple previous studies (23,9). "
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    ABSTRACT: Background The rapid evolution of transsphenoidal endoscopic surgical intervention and surgeries of skull base and sellar regions is accompanied by multiple complications. Objective To determine different types of extension of sphenoid sinus pneumatization detected by CT and MRI and their impact upon different approaches and complications of sellar region surgeries. Subjects and methods The pre-operative CT and MRI images of 182 patients with surgical intervention for peri-sellar region pathologies were retrospectively evaluated for patterns of sphenoid pneumatization. Post surgical complications were recorded and analyzed. Results The overall rate of complications was 88 affecting 62 patients (34%), and 120 patients (66%) were free of complications. Different types of pneumatization were detected on CT and MRI images, conchal in 3 cases (1.6%), presellar 23 cases (12.6%) and 156 cases (85.7%) showing sellar pneumatization. Sellar pattern was reclassified into 6 types. Single inter sphenoid septum was seen in 109 patients, accessory septum was found in 13 patients and 10 patients have multiple sphenoid septation. 24 patients (13.2%) show absent septum. Conclusion Pre-intervention assessment of sphenoid sinus pneumatization is mandatory in approaching the sella and skull base structures either via the nose or open skull base surgery to avoid injury of the nearby structures and reduce the possibility of CSF leakage.
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    • "We failed to observe pneumatization of the sphenoid sinus until the age of 8; however, this study was performed in a limited number of cases. Sellar and postsellar pneumatization accounted for 93.8% of all cases in the over 15 age group, suggesting that the degree of pneumatization in this age group is greater than reported previously7,13). "
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    • "Tatreau et al (15) reported that the periform aperture and pneumatization to the planum and sella changed with age in pediatric patients, but not in adult patients. Hamid et al (10) used CT and MRI scans to study variations of the sphenoid sinus in 296 patients with pituitary lesions. The authors found that the degree of pneumatization of the sphenoid sinus varied greatly but the appearance of the sellar bulge was prominent, which appeared in 75% of patients. "
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