Pseudocapsular Dissection Improves Residual, Recurrence Rates and Time to Recurrence in Cushing's Disease Patients

Objective: The pseudocapsular resection technique was first described by Dr. Edward Oldfield in 2006 in as a surgical method to improve gross total resections in patients with functioning pituitary adenomas where any residual could cause significant morbidity. Additionally, identification of the pseudocapsule has aided in finding microadenomas intraoperatively not visualized on imaging. The technique is more challenging than traditional intracapsular piecemeal resection and in the hands of unexperienced surgeons may increase the likelihood of generating a CSF leak. We aim to study in our large institutional series, whether achievement of pseudocapsular resection significantly reduces residual tumor and tumor recurrences in Cushing's disease patients.

Methods: An institutional review board–approved retrospective review was performed identifying all patients with diagnosed Cushing's disease who underwent an endoscopic transnasal transsphenoidal tumor resection between December 12, 2007, and August 16, 2019, at our institution. 86 patients were identified based on these inclusion criteria. Main outcome variables collected include tumor size, pseudocapsular dissection, post-operative residual, post-operative recurrence and time to recurrence.

Results: The average tumor size for our series was 5 mm for pseudocapsular resection cases and 5.5 mm for the remaining ones. The overall CSF leak rate for our series was 28.3%. There was no statistically significant difference between the pseudocapsular (16%) and no pseudocapsular (36%) resection group. In fourteen cases (16.5%), no clear tumor was visualized intraoperatively. Of those cases, 8 had biochemical remission, and only 3 had a remaining suspicious lesion on postoperative MRI. None of the patients who underwent pseudocapsular resection had residual tumor compared with 21% of patients without complete pseudocapsular resection. All patients who underwent pseudocapsular resection had biochemical remission postoperatively, with one partial, clinically insignificant, remission. There were no recurrences for patients after pseudocapsular resection, compared with 8 recurrences out of 74 patients who did not undergo en bloc pseudocapsular resection. Mean length of follow-up was 34.7 months. Of the patients where complete pseudocapsular resection was achieved, only 12.5% were adherent and 27% were soft, compared with 23% and 95% of tumors without en bloc pseudocapsular resection, respectively. If no residual tumor was identified on postoperative imaging, likelihood of biochemical remission in this patient population was 68%.

Conclusion: Pseudocapsular resection was found to be more likely achieved for nonadherent and semifirm tumors. Patients who underwent complete pseudocapsular resection, had no residual on postoperative imaging and no recurrence of their Cushing's disease for a mean follow-up of 34.7 months. All patients had biochemical remission after pseudocapsular resection. However, absence of residual on postoperative imaging was not a good positive predictor of postoperative biochemical remission (PPV 68%). Lastly, there was no significant difference in CSF leak rates between the pseudocapsular resection group and the remaining patients.

Publication History

Article published online:
12 February 2021