Resection of pituitary macroadenomas via the pseudocapsule along the posterior tumor margin: a cohort study and technical note

Abstract

OBJECTIVE Extracapsular resection of pituitary microadenomas improves remission rates, but the application of pseudocapsular techniques for macroadenomas has not been well described. In larger tumors, the extremely thin, compressed normal gland or its complete absence along the tumor's anterior surface limits the application of the traditional pseudocapsular technique that can be used for microadenomas. However, in the authors' experience, the interface between the pseudocapsule at the posterior margin of the adenoma and the compressed normal gland behind it is universally present, providing a surgical dissection plane. In mid-2010, the authors began using a new surgical technique to identify and use this interface for the resection of larger macroadenomas, a technique that can be used with the microscope or the endoscope. METHODS The authors performed a cohort study using prospectively collected preoperative imaging reports and operative details and retrospectively reviewed postoperative images and clinical follow-up of patients with a pituitary macroadenoma 20-40 mm in maximum diameter undergoing microscopic transsphenoidal resection. Since dissection of the tumor capsule only pertains to encapsulated tumor within the sella and not to tumor invading the cavernous sinus, assessment of tumor removal of noninvasive tumors emphasized the entire tumor, while that of invasive tumors emphasized the intrasellar component only. The incidence of residual tumor on postoperative imaging, new-onset endocrinopathy, and recovery of preoperative pituitary deficits was compared between patients who underwent surgery before (Group A) and after (Group B) implementation of the new technique. RESULTS There were 34 consecutive patients in Group A and 74 consecutive patients in Group B. Tumors in 18 (53%) Group A and 40 (54%) Group B patients had no evidence of cavernous sinus invasion on MRI. Use of the posterior pseudocapsule technique reduced the incidence of intrasellar residual tumor on postoperative MRI for tumors without cavernous sinus invasion (39% [Group A] vs 10%, p < 0.05) and in all tumors regardless of invasion (50% vs 18%, p < 0.005). The incidence of new endocrinopathy was less likely (25% vs 12%, p = 0.098) and the recovery of prior deficits more likely (13% vs 27%, p = 0.199) among patients treated using the pseudocapsule approach, although the differences are not statistically significant. CONCLUSIONS Use of the posterior pseudocapsule dissection plane can enhance the resection of pituitary macroadenomas.

Prediction of cavernous sinus invasion in patients with Cushing’s disease by magnetic resonance imaging

“…2,8,13 Laterally positioned Cushing's adenomas confer a greater risk of CSI due to disruption of the pseudocapsule dissection plane, which results in reduced likelihood of complete resection and a greater incidence of recurrent disease. 8,16,19,21 As reported here, we identified an imaging sign that predicts CSI with high specificity for pituitary adenomas adjacent to the CS. The SS denotes distinctive triangular margins of an adenoma in direct contact with the CS wall.…”

Outcome of endoscopic vs microsurgical transsphenoidal resection for Cushing’s disease

“…The superior intraoperative visualization afforded by the endoscopic approach may account for this finding. A much more unobstructed view of the operative field may facilitate resection of much of the tumor, especially the pseudocapsule ( 61 , 62 , 63 ).…”

Endonasal Endoscopic Surgery for Macroadenomas: New Understanding of Pseudocapsules

“…Regarding surgical technology, previous studies [3][4][5][6][7][8] have mainly used the surgical technology summarized by Old eld on the basis of the microscopic transseptal transsphenoidal approach (MTSS), which is more suitable for microadenomas or small macroadenomas [7]. For surgery involving larger adenomas, it is hard to distinguish the pseudocapsule from the anterior surface of the adenoma, which limits the application of extrapseudocapsular resection [9]. Re nements of the endoscopic image quality and developments in the surgical technique have occurred over the years.…”

“…We retrospectively collected data from 237 patients who underwent endoscopic transsphenoidal pituitary adenoma surgery by a single surgeon (ZDW) from 1/2017 to 8/2019. The data included a complete history, intraoperative observation, physical and neurological examinations, and radiological assessment.The distinction of the pseudocapsule is more di cult in tumors with a maximum diameter larger than 15 mm, according to the literature [9]. To re ect the difference in surgical technique between microadenomas and macroadenomas, 192 patients (tumor largest diameter 15-40mm) were included in this study.…”

“…The pituitary gland was resected possibly due to misjudging the pituitary capsule as a pseudocapsule [10]. Taylor et al [9] demonstrated there were strong trend that the rate of new pituitary dysfunction after surgery in extrapseudocapsular resection is lower than normal technique.In the study, we attempt to exclude interference of partial pseudocapsular resection to prove the advantage of extrapseudocapsular resection in a short-time. The rate in Group A was less than Group C (4/47 vs 8/36, p=0.078 ), has a strong trend toward signi cance.…”