CPA Tumors: The Learning Curve in a Surgeon's Initial 50 Cases

Objective Cerebellar pontine angle (CPA) tumors present with unique challenges for a new skull base surgeon. These include early clinical and ethical decisions in surgical patient selection, appropriate surgical approach, and safe intraoperative choices. With good training, decision making, and reflection, however, successful and safe outcomes can be achieved.

Methods Fifty consecutive cases of CPA tumor surgical cases over 2 years were analyzed retrospectively in the author's initial 2 years in practice. Pathologies include meningioma, acoustic neuroma, paraganglioma, hemangioblastoma, and metastasis. An analysis was performed on the first 25 patients and compared with the second 25 cases after initial experience was obtained. All cases were continuously self-reviewed and areas of improvement were identified.

Results The average size of the lesion was 3.4 cm and consisted of mostly meningiomas (25) and acoustics neuromas (15). Lesions were approached 84% of the time via a retrosigmoid approach. The rate of postoperative infection was 4%, the rate of CSF leak was 4%, the need for ventriculoperitoneal shunt was 4%, and the rate of facial nerve weakness at 6 months was 6%. The initial 25 patients were compared with the second group and outcomes were carefully evaluated. There was a significant improvement in cranial nerve deficits and facial nerve preservation, extent of resection, and good overall outcome (all p < 0.05). Improvements were noted in both the total group and the subset of acoustic neuromas. Additionally, there was a decrease need for early cerebrospinal fluid egress as the case number increased (p < 0.05). Length of surgery improved by 15% in the second group compared with the first group (p < 0.05)

Conclusion Young skull base neurosurgeons can become technically proficient operating on CPA tumors while achieving desired patient outcomes. Adequate preparation, careful decision making, safe intraoperative choices, and detailed reflection on success and failures are key for a young skull base neurosurgeon. Important surgical learning points include respecting all venous outflow, identifying and maintaining tumor capsule layers, endoscopic assistance, and understanding the advantages and disadvantages of aggressive CSF drainage.