Are drains useful for lumbar disc surgery? A prospective, randomized clinical study

In this prospective, observer-masked clinical study, we evaluated if insertion of a drain had a significant role in decreasing the existence and the size of postoperative epidural hematoma, which is believed to be a factor causing epidural fibrosis in patients undergoing lumbar discectomy.

Fifty patients undergoing lumbar disc surgery were randomly assigned to two groups: with or without insertion of a drain in the epidural space. A drain was inserted in 22 patients, whereas 28 were left without a drain. All patients were evaluated, by means of magnetic resonance imaging (MRI) on the first postoperative day, specifically looking for the existence and the size of epidural hematoma. The size of epidural hematoma was graded as none, minimal, moderate, or prominent. The patients were clinically examined preoperatively and at the follow-up of 6 months by Oswestry Disability Index and recurrence of pain. A follow-up MRI was repeated at 6 months, and the subsequent development of epidural fibrosis was evaluated.

Epidural hematoma was detected in 36% of patients with a drain and in 89% of patients without a drain (P=0.000). There were significant less number of minimum, moderate, and prominent sized hematomas in the group with a drain (P=0.000). On the 6-month follow-up, epidural fibrosis was found in 58.3% of patients without a drain and in 31.6% of patients with a drain (P=0.08). Late clinical outcome (improvement in Oswestry Index and no recurrent pain) was better in the group with drain, but not statistically significant (P=0.4).

Occurrence of hematoma in the epidural space is common after lumbar disc surgery even if meticulous hemostasis has been achieved. Insertion of a drain decreases both the incidence and the size of hematoma on the first postoperative day as detected by MRI. This may have practical implications for the prevention of significant postoperative fibrosis and obtaining better surgical outcome.