Internal carotid artery in the operative plane of endoscopic endonasal transsphenoidal surgery

Do Anatomical Variations of Sphenoid Sinus Influence Sella Exposure and Residual Disease in Pituitary Surgery? - A Study in an Indian Population

Introduction  Endoscopic transsphenoidal surgery (ETS) is the standard practice in pituitary surgeries. The sellar exposure becomes the main factor which determines the residual disease in ETS. Not many studies can be found in the literature on the influence of anatomical variations of the sphenoid on intraoperative sella exposure. Objective  The aim of the current study is to ascertain whether sphenoid sinus variations play a role in sellar exposure and residual tumor volume. Methods  This is a prospective study conducted in a south Indian tertiary care center between June 2020 to June 2022, with 21 study participants who were scheduled to have ETS. The relation of preoperative computed tomography (CT) and magnetic resonance imaging (MRI) parameters with the intraoperative area of sellar exposure and residual tumor volume was evaluated. Results  Sphenoid sinus dimensions, like presellar width (mean = 1.89 ± 0.51 cm), maximum width (mean = 2.94 ± 1.09 cm), presellar depth (mean = 1.14 ± 0.55 cm), suprasellar depth (mean = 1.08 ± 0.24 cm), infrasellar depth (mean = 2.36 ± 0.92 cm), presellar height (mean = 2.22 ± 0.47 cm), or the 9 internal carotid artery (ICA)-related measures, did not have any correlation with the mean intraoperative area of sellar exposure (0.57 ± 0.28 cm 2 ). Also, the adequacy of sellar exposure did not relate to the residual tumor. Preoperative tumor volume was found to be higher (20.2 [55.3-13.2] cm 3 ) in patients with residual tumor compared with those with no residual tumor (5.9 [6.8-5.2] cm 3 ). Tumor extension had a significant association with the residual tumor volume. Conclusion  According to the present study, anatomical variations of the sphenoid sinus do not influence the adequacy of sellar exposure. Further studies need to be undertaken concerning residual tumor volume as well as preoperative tumor volume and extension.

Carotid Artery-Cavernous Segment Injury during an Endoscopic Endonasal Surgery: A Case Report and Literature Review of the Overlooked Option for Surgical Trapping in the Hyperacute Phase

Internal carotid artery (ICA) injury is a catastrophic complication of endoscopic endonasal surgery (EES). However, its standard management, emergent endovascular treatment, may not always be available, and the transnasal approach may be insufficient to achieve hemostasis. A 44-year-old woman with pituitary adenoma underwent EES complicated with the ICA cavernous segment injury (CSI). In urgent intraoperative angiogram, a good collateral flow from the contralateral carotid circulation was observed. Due to the unavailability of intraoperative embolization, emergent surgical trapping was performed by combined transcranial and cervical approach. The patient recovered but later developed a giant cavernous pseudoaneurysm. During the pseudoaneurysm embolization, ICA was directly accessed via a 1.7-F puncture hole using a bare microcatheter technique. Then, both the aneurysm and parent artery were obliterated with coils. At the 4-year follow-up, the patient was asymptomatic without a residual tumor. To our knowledge, this is the first case of ICA-CSI during EES successfully treated with ICA trapping as a lifesaving urgent surgery that achieved a complete recovery after a pseudoaneurysm embolization. Although several studies reported that EES-related ICA-CSIs with percutaneous carotid artery access, neither our surgical salvage technique nor our carotid access and tract embolization techniques were previously described.

Radiological "Teddy Bear" Sign on CT Imaging to Aid Internal Carotid Artery Localization in Transsphenoidal Pituitary and Anterior Skull Base Surgery

Objectives  Internal carotid artery (ICA) injury remains a rare but potentially fatal complication of transsphenoidal pituitary or anterior skull base surgery. Preoperative imaging must be scrutinized to minimize risk. On axial computed tomography (CT), the protrusions of the ICAs into the sphenoid resemble a "teddy bear." This article aims to describe the sign, its grading system (0-2) and quantify its presence. Design  Retrospective review of preoperative CT imaging. Setting  Tertiary referral center in the United Kingdom. Participants  One hundred patients who underwent endoscopic transsphenoidal surgery for pituitary disease were enrolled. Main Outcome Measure  The presence and grading of the "teddy bear" sign were assessed on preoperative CT imaging. Results  A grade 2 (strongly positive) "teddy bear" sign was identified in 40% at the level of the superior pituitary fossa, 78% at the inferior pituitary fossa, and 59% at the clivus. A grade 1 (intermediate) sign was seen in 23.5, 7.5, and 10% of cases, respectively. In 5% of cases, the sign was grade 0 at all levels-indicating poor intraoperative localization of the ICA. Conclusion  The "teddy bear" sign is a useful preoperative tool for identification of anatomy predisposing patients to a higher risk of ICA injury. Those patients who have an absent or grade 0 "teddy bear" sign require extra care to ensure intraoperative localization of the ICAs which may include the use of neuronavigation or a Doppler probe. A grade 2 sign predicts good intraoperative localization of the ICA intraoperatively to inform the safe lateral limit of sellar bone resection.

Pituitary macroadenoma: analysis of intercarotid artery distance compared to controls

Objective To evaluate the intercarotid distance (ICD) of patients with pituitary macroadenoma and compare to heatlhy controls. Method We retrospectively reviewed contrast-enhanced MRI images from twenty consecutive patients diagnosed with non-functioning pituitary macroadenoma, measured the ICD at two different levels (petrous segment - ICD1 and horizontal cavernous segment - ICD2) and compared to twenty paired controls. Results There was no statistically significant difference of the mean ICD1 between the groups and subgroups. For the ICD2 there was statistically significant difference between the case and controls. However, there was no significant difference between the patients with smaller adenomas and the controls. In contrast, the patients with giant adenomas showed statistically significantly higher ICD2 than the controls. Conclusion The ICD at the horizontal segment of the cavernous carotid tends to be wider in patients with giant pituitary adenomas than in healthy individuals or patients with smaller adenomas.

Quantitative analysis of anatomical relationship between cavernous segment internal carotid artery and pituitary macroadenoma

Cavernous segment internal carotid artery (CSICA) injury during endoscopic transsphenoidal surgery for pituitary tumor is rare but fatal. The aim of this study is to investigate anatomical relationship between pituitary macroadenoma and corresponding CSICA using quantitative means with a sense to improve safety of surgery.In this retrospective study, a total of 98 patients with nonfunctioning pituitary macroadenomas undergoing endoscopic transsphenoidal surgeries were enrolled from 2005 to 2014. Intercarotid distances between bilateral CSICAs were measured in the 4 coronal levels, namely optic strut, convexity of carotid prominence, median sella turcica, and dorsum sellae. Parasellar extension was graded and recorded by Knosp-Steiner classification.Our findings indicated a linear relationship between size of pituitary macroadenoma and intercarotid distance over CSICA. The correlation was absent in pituitary macroadenoma with Knosp-Steiner grade 4 parasellar extension.Bigger pituitary macroadenoma makes more lateral deviation of CSICA. While facing larger tumor, sufficient bony graft is indicated for increasing surgical field, working area and operative safety.

Analysis of sphenoid sinus in the operative plane of endoscopic transsphenoidal surgery using computed tomography

Recently, the endoscopic transsphenoidal approach for sphenoid sinus or intracranial lesion has gained more popularity and the study of the surgical anatomy and relationships of the sphenoid sinus has gained increased significance. The aim of this study was to clarify the anatomical features of the sphenoid sinus including surrounding structures as seen in the operative view of endoscopic transsphenoidal surgery. The various distances in the sphenoid sinus as well as the relationships between the sphenoid sinus ostium (SO) and important structures such as the optic canal (OC) and carotid artery (CA) according to the presence of Onodi cell (sphenoethmoidal cell; Onodi group vs. non-Onodi group) were assessed using multiplanar and three-dimensional model of CT scans in 100 patients. The SO was more inferior in Onodi group and located superior to the lowest point of the sella. The horizontal distance from the SO to sella was approximately 13 or 14 mm depending on the existence of Onodi cells. Regardless of Onodi cell, the whole course of the OC in the sinus ran superolaterally to inferomedially in the endoscopic view. However, Onodi cell made the angles from the SO to OC larger. In Onodi group, the CA was located from the SO in a superolateral direction, but in non-Onodi group, the CA was located from the SO in the inferolateral direction. This study provides anatomical information about the sphenoid sinus, with important surgical distances between the SO and surrounding structures measured, which is essential to avoid complications during transsphenoidal surgery.