Hydroxyapatite Use in Repair of Lateral Skull Base CSF Leaks Via Transmastoid Approach: When Does It Work?

OBJECTIVE

The objective of this study is to evaluate the efficacy and outcomes of using a transmastoid approach with hydroxyapatite cement to repair lateral skull base cerebrospinal fluid (CSF) leaks.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary-level care hospital.

PATIENTS

Surgical patients 18 years or older between 2013 and 2022 with spontaneous CSF leak.

INTERVENTIONS

Trans-mastoid approach for skull base repair using hydroxyapatite cement.

MAIN OUTCOME MEASURES

Failure rate of repair; location and size of defect, patient demographic factors.

RESULTS

Of the 60 total defects (55 patients, 5 bilateral repairs) that underwent CSF leak repair using hydroxyapatite cement, the success rate was 91.66% (55 successful repairs). The average defect size in unsuccessful repairs was 1.15 cm compared with 0.71 cm for successful repairs. In addition, 80% (4/5) of the failed repairs were in the tegmen tympani region. Higher failure rate was noted in women (3/5) and in former smokers (4/5). Average time to recurrent symptoms was 1.75 years in the failed repair cohort. Of the patients with failed repairs, 4/5 were prescribed acetazolamide before their second procedure with successful second repair. In addition, five patients experienced postoperative headaches, three (5.4%) of whom required placement of VP shunts to relieve increased intracranial pressure. Two patients (3.6%) had complications of either infection or hearing loss.

CONCLUSIONS

Transmastoid approach utilizing hydroxyapatite is a successful approach for CSF leak repair, with a low complication and failure rate. Women, prior smoking history, and larger defects in the tegmen tympani region may need alternative materials or approach for repair. Long follow-up is warranted as recurrence of symptoms might be delayed. In cases of benign intracranial hypertension, adjuvant treatment with either acetazolamide or VP shunt placement may prevent failures.