Evaluation of the Learning Curve for Pediatric Endoscopic Endonasal Surgery: Twenty-Three Years of Experience at a Single Institution

Introduction: There is a considerable learning curve in performing endoscopic endonasal neurosurgery which may be even more pronounced when dealing with pediatric cases. The authors present their experience treating skull base pathologies in pediatric patients over a 23-year period. They show time-trends in patient population, operative approach, and complications over this period.

Methods: The authors reviewed clinical characteristics of patients with skull base pathologies treated with endoscopic endonasal surgery (EES) at a large tertiary pediatric hospital between 1999 and 2022. This time period was separated into three categories: 1999–2007, 2008–2015, and 2016–2022. Group differences in categorical variables were assessed using Pearson’s Chi-square test and differences in continuous variables were assessed using analysis of variance (ANOVA).

Results: Two hundred and forty-three patients comprise the study sample. There was a nonsignificant trend toward a higher proportion of patients with recurrent pathology following treatment at another institution (21, 18, and 29% over time, p = 0.19).

There was a significant increase in the proportion of patients with chordoma (6, 10, 23%, p = 0.01) and a decrease in the proportion with pituitary adenoma (16%, 5%, 7%, p = 0.03). There were also trends towards an increasing proportion with odontoid pannus or basilar invagination (0%, 4%, 7%, p = 0.11) and a decreasing proportion with Rathke cleft cyst (13%, 7%, 4%, p = 0.14). In later time periods the authors treated a greater proportion of patients with pathology in the posterior fossa (10%, 17%, 35%) and coronal plane (30%, 31%, 34%) and a lesser proportion in the sellar/suprasellar region (43%, 35%, 23%) and anterior fossa (17%, 17%, 9%; p = 0.003).

In later time periods, a greater proportion of cases was combined with posterior cervical fixation (0%, 4%, 9%, p = 0.028) and there was increased utilization of the anterior transmaxillary approach (0%, 13%, 15%, p = 0.007) as well as preoperative embolization (6%, 15%, 21%, p = 0.047). Later time periods also saw increased utilization of free mucosal grafts (2%, 17%, 19%, p = 0.006) and vascularized pedicled flaps (29%, 45%, 59%, p = 0.002). There was no significant change in the rate of gross-total resection of tumors.

Despite treating more complex pathologies, the authors found no statistically significant change in overall complications (16%, 13%, 12%, p = 0.8), hemorrhage (3%, 4%, 0%, p = 0.245), major vascular injury (0%, 3%, 1%, p = 0.36), or stroke (0%, 0%, 1%, p = 0.3). There was a trend towards a decreased rate of cerebrospinal fluid leak (32%, 14%, 17%, p = 0.2), but this association did not reach statistical significance. The rate of permanent new cranial nerve deficits increased with time (3%, 9%, 13%, p = 0.012), which mirrors the increase in frequency of malignant posterior fossa cases where cranial nerves are at risk. There was no significant change in the rates of permanent new visual deficit (2%, 3%, 0%, p = 0.17), diabetes insipidus (3%, 11%, 7%, p = 0.14), or panhypopituitarism (8%, 10%, 4%, p = 0.28).

Conclusion: With time, the authors’ practice has evolved to take on a greater proportion of complex pathologies in challenging anatomical locations with minimal increased morbidity. Their practice pattern has changed to incorporate more advanced reconstruction techniques, combined approaches, alternative operative corridors, and adjunctive preoperative treatments.