Analysis of Lumbar Puncture Opening Pressures Before and after Closure of Spontaneous Anterior and Lateral Cranial Base Cerebrospinal Fluid Leaks

Introduction: Spontaneous cerebrospinal fluid (sCSF) leaks are often caused by elevated intracranial pressures (ICP). A lumbar puncture (LP) measuring the opening pressure (OP) may be performed at the time of surgical closure of the skull base defect to identify patients with an elevated ICP. However, if the patient is actively leaking CSF at the time of surgery, then this may lead to a falsely decreased representation of the longstanding ICP. Moreover, long-term treatment of high ICP with diuretics or ventriculoperitoneal shunts is often dictated by the LP opening pressure. The purpose of this study is to compare the lumbar puncture opening pressures before and after surgical closure of anterior and lateral cranial base spontaneous CSF leaks.

Objectives: To compare pre- and postoperative LP opening pressures in patients undergoing anterior or lateral cranial base CSF leak repair and analyze factors that influence this change

Methods: Retrospective study of patients between 2014 and 2020 who underwent repair of a spontaneous CSF leak with an LP opening pressure measured at the time of closure and within 6 months postoperatively undertaken at a large volume academic center. ANOVA and Chi-square test used as appropriate for statistical analysis using SPSS 26 (IBM Corp)

Results: Over the last decade, more than 126 patients underwent surgery for sCSF leaks at our institution. Since 2014, eighteen patients—6 with lateral and 12 with anterior leaks underwent repairs with lumbar opening pressures measured pre and within 6 months postoperatively.

Demographics: The majority of patients were females 14 (78%), mean age was 57 years (SD: 15.6), and the mean BMI was 32 (SD: 6.74).

Mean pre- and postoperative opening pressures were 17 (SD = 5) and 21 (SD = 6) cm of water, respectively. Patients with post-repair spike had mean pre- and post-op opening pressures of 16 (SD = 5) and 26 (SD = 3) cm of water, respectively. Patients with lateral skull base defects were significantly more likely to have a high flow leak when compared to anterior (6 vs. 3, p = 0.03).

Postoperative opening pressure spike of more than 5 cm of H₂O was recorded in 67% (4) of lateral and 33% (4) of anterior cohort (p = 0.18) patients. Among these 4 patients in lateral and 3 in anterior cohorts had an active leak before surgery, whose mean post-op pressures rose to more than 25 mm of water (mean = 26.3). Three of them were advised and received a VP shunt according to our management algorithm. None of our patients had a recurrence within the mean follow-up period of 826 days (SD = 730 days).

Discussion: In our study, 50% of patients' had an erroneously low preoperative opening pressure, with 39% having a postoperative spike of more than 5 cm of water. Lateral leaks are more likely to have high flow leaks and erroneously low pre-op opening pressures.

Conclusion: Preoperative opening pressures may be erroneously low in actively laking patients. Further studies are required to validate this.

Publication History

Article published online:
12 February 2021