Influence of head position on the effectiveness of twist drill craniostomy for chronic subdural hematoma.

BACKGROUND: Twist drill craniostomy with closed system drainage (TDC-CSD) is a well-accepted treatment of chronic subdural hematomas (CSDH). Although this intervention has a long track record of effectiveness, little is known of its relationship with the head position of the patient (flat vs elevated). This study evaluated if the position of the patient's head influences outcome.

METHODS: The database of a University Hospital Center was queried for patients who had CSDH treated by TDC-CSD between January 1997 and March 2001. Identified patients were grouped into 2 categories: head of bed (HOB) at 30% and HOB flat while undergoing treatment. Outcomes were then evaluated with regard to amount of drainage, complications, recurrence, and length of hospital stay (LOS).

RESULTS: Forty-four patients were identified who received TDC-CSD treatment of CSDH. Of these, 24 patients had flat HOB and 20 had HOB elevated to 30 degrees . Although patients with elevated HOB had higher amounts of drainage (239 vs 166 mL), this figure did not reach statistical significance (P = .23). The number of recurrences and complications likewise did not reach statistical significance. Despite these findings, a statistically significant difference in LOS was found between the groups (flat = 5.5 days, elevated = 8.1 days, P = .03). This was believed secondary to bias resulting from placing the HOB of healthier patients (based on Glasgow Coma Scale) flat.

CONCLUSIONS: Elevation of the patient's head during TDC-CSD treatment of CSDH does not seem to impact the amount of drainage, recurrence frequency, or complication rate. Although a statistically significant difference in LOS was observed based on this variable, it appeared to be the result of bias in patient selection for HOB elevation.