The "O-Ring" technique is effective in reducing cerebrospinal fluid leak in posterior fossa surgery

Posterior fossa approaches are commonly used during routine neurosurgery. Cerebrospinal fluid (CSF) leakage is one of the most important posterior fossa surgery-related complications. CSF leakage can manifest as both pseudomeningocele and external leakage. If craniotomy or craniectomy is performed, the skull defect can be repaired using heterologous polymethylmethacrylate (PMMA) cranioplasty. The aim of this study was to evaluate the clinical results of the O-ring technique in terms of postoperative complications.

Patients treated using the retrosigmoid (RS), key-hole RS, or cerebellar hemispheric approach with O-ring PMMA cranioplasty were selected. Data analysis considered age, sex, pathology, surgical approach, presence of preoperative hydrocephalus, wound closure problems, and CSF-related complications postoperatively and at one- and three-month follow-ups.

Thirty-three patients were selected, and meningioma was the most common disease. The majority of patients (60.6%) were treated with the standard RS approach. No patient presented with surgical complications in terms of pseudomeningocele or external CSF leakage, neither postoperatively nor at the one-month follow-up. On three-month follow-up MRI, subcutaneous fluid collection was observed in two patients (6.1%).

Our study shows promising results that the O-ring technique could represent a valid option to reduce postoperative CSF leakage in posterior fossa surgery.