When the Drain Hits the Brain

The insertion of a subdural drain (SDD) after burr-hole drainage of chronic subdural hematoma (cSDH) was shown to reduce recurrence rate and improve outcome at 6 months. However, studies analyzing the rate of drain misplacement and complications associated with drain misplacement are sparse.

We analyzed retrospectively a cohort of consecutive patients undergoing burr-hole drainage for cSDH in 2 institutes. Drain type (subperiosteal drain vs. SDD), drain misplacement rate, and drain-associated complications were analyzed. We explored potential risk factors for drain misplacement and associated complications in the SDD subgroup using univariate and multivariate analysis. Drain misplacement was defined as incorrect drain position exceeding the subdural cavity and was categorized into drain misplacement without radiologic sequelae, drain misplacement causing radiologically confirmed iatrogenic bleeding, and drain misplacement causing neurologic symptoms.

Of 463 included patients, 290 (62.6%) received an SDD. Drain misplacement occurred in 73 patients (15.8%). In 5 (6.9%) and 9 (12.3%) of these patients, iatrogenic bleeding and neurologic symptoms occurred, respectively. Intake of vitamin K antagonists (odds ratio [OR], 3.64) or different oral anticoagulants (OR, 10.24), and low preoperative Glasgow Coma Scale score (OR, 7.81) remained associated risk factors for drain misplacement after multivariate analysis. Patients with misplaced drains showed a strong association with postoperative bleeding (OR, 5.81), longer operation time (OR, 1.01), and hospitalization time (OR, 1.08) after multivariate analysis.

The occurrence of SDD misplacement is unignorable, because it leads to iatrogenic drain-associated complications and seems to affect bleeding events and hospitalization time of patients undergoing burr-hole drainage of cSDH.