Effect of the "O-ring" Technique in Reducing Cerebrospinal Fluid Leak in Posterior Fossa Surgery: an Explorative Study (O'Ring)

Posterior fossa surgery represents on of the most demanding procedure in neurosurgery. Retrosygmoid (RS), key-hole retrosygmoid (KR) and cerebellar hemispheric (CH) are the most common approaches used to access in this area. Despite they are not technically difficult to perform, these approaches can be burdened by postoperative cerebrospinal fluid (CSF) leakage, both at short and long-term follow-up, with an high risk of meningitis. Many techniques were employed to avoid this risk, but it can still be estimated between 2% and 11% according to literature1-4. Spena et al. reported a CSF leakage rate of 6.8% in a previous experience5. As a consequence, newer efforts are necessaries to avoid this potentially lethal complication. By this explorative study, we want to retrospectively analyzed our experience with a newer technique of bone closure, called O'Ring, in patients subdued to posterior fossa surgery by RS, KR and CH approaches, focusing on postoperative CSF leakage (primary objective), wound complications and subcutaneous CSF collections (secondary objectives).

Study Overview

• Status: Completed
• Conditions: Posterior Fossa Surgery
• Intervention / Treatment: Procedure: O-ring technique

• Study Type: Observational
• Enrollment (Actual): 35

Contacts and Locations

Study Locations

• Italy
  • Pavia, Italy, 27100
    • SC Neurochirurgia, Fondazione IRCCS Policlinico San Matteo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients operated for a disease located in posterior fossa for which a RS, KR or CH approach has to be performed. Patients between January 2018 and October 2023 will be considered for the study.Lacking of clinical, radiological and surgical data represented exclusion criteria.

Description

Inclusion Criteria:

• age ≥18 years,
• availability of pre- and postoperative radiological and clinical data,
• a follow-up period of at least 3 months.

Exclusion Criteria:

• Lacking of clinical, radiological and surgical data

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients operated for a disease located in posterior fossa; Patients operated for a disease located in posterior fossa for which a RS, KR or CH approach has to be performed. Patients between January 2018 and October 2023 will be considered for the study. Lacking of clinical, radiological and surgical data represe	Procedure: O-ring technique; "O-ring technique." consists on a different arrangement of fibrin-glue on a polymethilmetacrylate cranioplasty, with the aim to create a gasket to prevent CSF leakage

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
to estimate incidence of postoperative CSF leakage	cumulative incidence of postoperative CSF leakage	7 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
to estimate incidence CSF leakage at 1- and 3-months of follow-up.	cumulative incidence of CSF leakage at 1- and 3-months follow-up	1 and 3 months
to estimate the incidence of wound complications postoperatively and at 1- and 3-months	cumulative incidence of wound complications postoperatively and at 1- and 3-months follow-up	1 and 3 months
to estimate the incidence of subcutaneous CSF collections postoperatively and at 1 and 3-months radiological follow-up	cumulative incidence of subcutaneous CSF collections postoperatively and at 1 and 3-months radiological follow-up	1 and 3 months

Collaborators and Investigators

• Sponsor: Fondazione IRCCS Policlinico San Matteo di Pavia

Study record dates

Study Major Dates

• Study Start (Actual): July 16, 2024
• Primary Completion (Actual): October 30, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: September 27, 2024
• First Submitted That Met QC Criteria: September 27, 2024
• First Posted (Actual): October 1, 2024

Study Record Updates

• Last Update Posted (Actual): May 1, 2025
• Last Update Submitted That Met QC Criteria: April 29, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Wounds and Injuries; Craniocerebral Trauma; Trauma, Nervous System; Cerebrospinal Fluid Leak
• Other Study ID Numbers: O'Ring

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No