Learning curve for the endoscopic endonasal approach for suprasellar craniopharyngiomas

The endoscopic endonasal approach is considered an alternative minimally invasive approach for suprasellar craniopharyngiomas. However, the complicated surgical manipulations required by this approach have limited its application. We evaluate whether the approach features a learning curve. Thirty-three patients were retrospectively reviewed and grouped as early (17 patients) and late (16 patient) groups. The operation time, extent of removal, ophthalmology, endocrinology, reconstruction and modifications of standard technique were evaluated. Between the two groups, the operation time decreased from 201.1±105.3min in the early group to 107.6±90.0min in the late group (p<0.05). Regarding clinical outcomes, non-significantly increasing trends toward the rate of gross total resection, visual improvement and (from 76.5% to 87.5%, 73.3% to 93.3%), significantly decreasing trends toward the rate of tumor recurrence (from 23.5% to 0% p<0.05) and non-significantly decreasing trends toward the rate of hypopituitarism recovery (26.7% to 0%) were observed between the two groups. With respect to complications, non-statistically significant decreasing trends toward transient cranial nerve paralysis (from 5.9% to 0%) and non-statistically significant increasing trends toward rate of CSF leakage, meningitis and new hypothyroidism (from 11.8% to 25%, 11.8% to 31.3%, 0 to 3%) were observed. We identified a learning curve for the endoscopic endonasal approach for suprasellar craniopharyngiomas. The exact number of patients necessary to establish a significant improvement in the clinical outcomes and decrease in the complications warrants further investigation. The outcomes of tumor recurrence may be associated with duration of follow-up. The CSF leakage represented the most common complication.