A randomized controlled trial comparing the outcome of burr-hole irrigation with and without drainage in the treatment of chronic subdural hematoma: a preliminary report

Background: Burr-hole is the most frequently used neurosurgical treatment for chronic subdural hematoma (CSDH). Few data can be found in the literature confirming the impact of using drainage after evacuation and irrigation of the cavity containing CSDH on the outcome of the patients. It is not clear whether installing such a drainage system would reduce the recurrence rate.

Objective: The aim of this study was to compare the postoperative recurrence rates and the chance of occurrence of other possible complications between a group treated by burr-hole irrigation without drainage (BI-D) and burr hole-irrigation with drainage (BI+D).

Materials and methods: Forty patients experiencing CSDH were included in a randomized controlled trial conducted between June 2007 and July 2009. All underwent surgery and were analyzed in this preliminary report. Twenty patients were assigned to BI+D group and the other 20 to the BD-I group. Inclusion and exclusion criteria are defined, and the cases happened to be well matched. All the epidemiologic, clinical, radiologic, procedure-related, and outcome variables were saved in the data sheaths and analyzed by the use of SPSS v 14. The patients were followed by an independent observer, who visited the patients at 1- and 6-month intervals.

Results: There were 28 male and 12 female patients (2.3:1) with the age range between 18 and 96 years (mean, 67 years; SD, 18 years). Glasgow coma scale scores varied between 9 and 15 in 37 patients and less than 9 in the other 3 patients. A history of head trauma was established in 25 patients. Limb weakness, loss of consciousness, and headache were the most common presentations. Recurrence occurred in one patient (5%) in BI+D and in none of the patients in BI-D group after 1-month follow up, without significant statistical difference (P = 0.31). At the end of 6 months there was one more recurrence (5%) in BI-D group, and the recurrence rates became equal. Both patients who experience a recurrence used antiplatelet drugs, and the one in BI-D group also had diabetes. The morbidity and mortality rates were greater in BI+D group, but these finding were not statistically significant (P = 0.37 and 0.73, respectively). There were no significant differences between the two surgical approaches regarding their relation with the recurrence of CSDH, the patient's morbidity, or mortality. The relative risk was greater for BI+D when the primary and secondary outcome measures were taken into account, but it was not significant statistically.

Conclusion: Type of surgical technique does not seem to be a main variable improving the outcome of such patients and may act as a confounding factor. Age, neurological status, and comorbidities seem to have more significant impact upon the surgical outcome.