Cranioplasty is a commonly performed neurosurgical procedure used to repair defects of the cranial vault. For large defects, 3D printing allows for the creation of patient-specific synthetic cranioplasties. Although these implants provide excellent cosmetic results for patients, costs are quite high. This makes their routine use challenging in the current Canadian healthcare environment. The purpose of this study is to report our experience with a novel, cost-effective method for cranioplasty using desktop 3D printers to manufacture patient-specific molds to aid in the shaping of polymethyl methacrylate (PMMA) cranioplasty intraoperatively.

A retrospective review of patients who underwent cranioplasty utilizing 3D printed custom molds was conducted at a single center between 2018 and 2020. Either a two-piece self-align or open-air mold was utilized. Material cost, as well as demographic, clinical, and radiologic data, was reviewed. A five-point ordinance scale was used to evaluate patient satisfaction with cosmesis.

Four patients had previous craniectomies with infected bone flaps, 2 patients had significant bony destruction from tumor invasion, and 1 patient had bone flap resorption. Three patients underwent an open-air mold technique with a Ti-mesh/PMMA-combined implant. The remaining 4 patients underwent two-piece mold with PMMA-only implant. All patients had ‘Good’ to ‘Excellent’ cosmetic outcome with one post-operative acute subdural hematoma and one post-operative infection. Two-piece mold resulted in improved cosmetic outcome and cost savings.

3D printing can be used in a cost-effective manner to deliver good cranioplasty cosmesis. Wider adoption of this technique can result in significant healthcare cost savings without compromising patient outcome.

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumefactive lesion. CAPNONs can mimic calcified meningiomas at the skull base.

Here, we report two cases of CAPNON and present a systematic review of the literature on skull base CAPNONs, to compare CAPNONs with calcified meningiomas.

Case 1: A 57-year-old man presented with right-sided lower cranial neuropathies and gait ataxia. He underwent a subtotal resection of a right cerebellopontine angle lesion, with significant improvement of his gait ataxia. However, his cranial neuropathies persisted. Pathological examination of the lesion was diagnostic of CAPNON, with the entrapped nerve fibers identified at the periphery of the lesion, correlating with the patient’s cranial neuropathy. Case 2: A 70-year-old man presented with progressive headache, gait difficulty, and cognitive impairment. He underwent a frontotemporal craniotomy for a near-total resection of his right basal frontal CAPNON. He remained neurologically stable 7 years after the initial resection without evidence of disease recurrence. We analyzed 24 reported CAPNONs at the skull base in our systematic review of the literature. Cranial neuropathies were present in 11 (45.8%) patients. Outcomes regarding cranial neuropathies were documented in six patients: two had sacrifice of the nerve function with surgical approaches and four had persistent cranial neuropathies.

While CAPNON can radiologically and grossly mimic calcified meningiomas, they are two distinctly different pathologies. CAPNONs located at the skull base are commonly associated with cranial neuropathies, which may be difficult to reverse despite surgical intervention.