Surgical Outcomes following Repeat Transsphenoidal Surgery for Nonfunctional Pituitary Adenomas: A Retrospective Comparative Study

Background/Objective Endonasal transsphenoidal surgery (TSS) remains the preferred treatment for most recurrent or residual nonfunctional pituitary adenomas (NFPAs). The objective of this study was to compare surgical outcomes from primary and repeat TSS in patients with NFPAs at a dedicated tertiary pituitary center.

Methods This is a retrospective review of 1,678 transsphenoidal cases performed at USC between 1995 and 2015. Inclusion criteria consisted of patients with NFPAs treated with endoscopic or microscopic endonasal TSS with a minimum follow-up of 3 months. Patients were categorized as primary or repeat TSS. Patient and tumor characteristics were compared preoperatively, and postoperative outcomes were analyzed.

Results Two hundred sixty-eight patients met inclusion criteria with appropriate follow-up. Of these, 211 patients underwent primary TSS and 57 patients underwent repeat TSS. Median follow-up time was 25 months (range: 3–235 months). Both groups had similar baseline demographic characteristics and endocrine function. Patients undergoing repeat TSS had a higher rate of receiving prior radiation therapy (10.5 vs. 0%, p < 0.001) or radiosurgery (10.5 vs. 0%, p < 0.001). A higher incidence of headaches (37.9 vs. 14.0%, p = 0.001) and visual field deficits (47.2 vs. 27.4%, p = 0.018) were observed in the primary TSS group. Tumor diameter and invasion/extension patterns were similar in both groups; however, the rate of gross-total resection (GTR) was significantly higher in primary TSS patients (59.0 vs. 27.8%, p = 0.001). In both groups, the presence of cavernous sinus invasion made it less likely to achieve GTR (OR = 0.28, CI 95%: 0.17–0.48, p < 0.001) and the use of an endoscopic endonasal approach was more likely to result in GTR (OR = 1.73, CI 95%: 1.26–2.38, p = 0.001). There were no mortalities in either group, and complication rates (cerebrospinal fluid leak, vision loss, hematoma, stroke, etc.) were comparable between groups. A significantly higher rate of early hospital readmission due to hyponatremia was observed in the primary TSS group (6.6 vs. 0.0%, p = 0.046). Repeat TSS group demonstrated a lower rate in vision improvement (primary TSS: 45.1% vs. repeat TSS: 20.0%, p = 0.005) and higher rate of new panhypopituitarism (primary TSS: 0.5% vs. repeat TSS: 7.1%, p = 0.011). A higher percentage of adjuvant radiosurgery was performed in the repeat TSS group (primary TSS: 24.1% vs. repeat TSS: 38.9%, p = 0.009).

Conclusion At experienced tertiary pituitary centers, repeat endonasal TSS for NFPAs is associated with a similar incidence of surgical complications as in patients undergoing primary TSS. However, repeat TSS demonstrated a lower rate of GTR, and carried a higher rate for worsening endocrine dysfunction.