Postoperative spinal epidural hematoma (SEH): incidence, risk factors, onset, and management

Abstract

Background context

Spinal epidural hematoma (SEH) is a rare, yet potentially devastating complication of spinal surgery. There is limited evidence available regarding the risk factors and timing for development of symptomatic SEH after spinal surgery.

Purpose

To assess the incidence, risk factors, time of the onset, and effect of early evacuation of symptomatic SEH after spinal surgery.

Study design

Multicenter case control study.

Patient sample

All patients who underwent open spinal surgery between October 1, 1999, and September 30, 2006, at the National Hospital For Neurology and Neurosurgery (NHNN) and the Wellington Hospital (WH) were reviewed.

Outcome measures

Frankel grade.

Methods

Patients who developed SEH and underwent evacuation of the hematoma were identified. Two controls per case were selected. Each control had undergone a procedure with similar complexity, at the same section of the spine, at the same hospital, and under the same surgeon within 6 months of the initial operation.

Results

A total of 4,568 open spinal operations were performed at NHNN and WH. After spinal surgery, 0.22% of patients developed symptomatic SEH. Alcohol greater than 10 units a week (p=.031), previous spinal surgery (p=.007), and multilevel procedures (p=.002) were shown to be risk factors. Initial symptoms of SEH presented after a median time of 2.7 hours (interquartile range [IQR], 1.1–126.1). Patients who had evacuation surgery within 6 hours of the onset of initial symptoms improved a median of 2 (IQR, 1.0–3.0) Frankel grades, and those who had surgery more than 6 hours after the onset of symptoms improved 1.0 (IQR, 0.0–1.5) Frankel grade, p=.379.

Conclusions

Symptomatic postoperative SEH is rare, occurring in 0.22% of cases. Alcohol consumption greater than 10 units a week, multilevel procedure, and previous spinal surgery were identified as risk factors for developing SEH. Spinal epidural hematoma often presents early in the postoperative period, highlighting the importance of close patient monitoring within the first 4 hours after surgery. This study suggests that earlier surgical intervention may result in greater neurological recovery.

Introduction

Evidence & Methods

Postoperative symptomatic spinal epidural hematoma (SSEH) associated with progressive or severe neurological loss usually requires emergent surgical evacuation. However, since virtually all postoperative patients have some degree of epidural hematoma and pain after decompression procedures, appreciation of additional risk factors or specific postoperative findings for symptomatic hematoma is important.

In this retrospective case series review from a single center, the rate of SSEH was 0.22%. Regular alcohol use, multilevel surgery, and revision surgery were specific risk factors. “Early” decompression, performed within 6 hours after the appreciation of “maximum neurological deficit,” appeared to be associated with better recovery. However, in the absence of catastrophic neurologic loss, the early specific findings of SSEH were not well defined.

These findings reinforce the anecdotal observation of many experienced spine surgeons that operative intervention for SSEH may be indicated every 1 or 2 years in a busy practice. While the keys to successful treatment remain diligent monitoring, early recognition, and rapid surgical decompression, this study highlights the difficulty in distinguishing specific postoperative symptoms or signs that constitute a bona fide surgical emergency from unrelated or minor postoperative findings in which reoperation would be unhelpful.

—The Editors

Jackson [1] is thought to have described the first case of spinal epidural hematoma (SEH) in 1869. Since then, more than 350 cases with various etiologies have been reported in the literature [2], [3], [4], [5].

Symptomatic postoperative SEH is a rare, yet well-recognized complication of spinal surgery with the potential for leaving patients with devastating consequences such as paralysis and a lifetime bound to the wheelchair.

Most patients after spinal surgery demonstrate a varying degree of epidural hematoma on imaging. However, most remain asymptomatic. In patients undergoing lumbar surgery, Sokolowski et al. [6] identified a 58% incidence of asymptomatic compressive postoperative epidural hematoma compressing the thecal sac beyond its preoperative state at one or more levels. It is therefore impractical and unnecessary to perform a postoperative magnetic resonance imaging scan on all patients. However, prompt attention should be paid to patients who develop either new or deteriorating neurologic signs and symptoms postoperatively.

The reported incidence of symptomatic postoperative SEH requiring surgical evacuation varies significantly from 0.1% up to 1% [7], [8]. Interestingly, over 70% of spinal surgeons consider the risk of SEH after a major spinal surgery to be over 1% [9].

Given the devastating consequences of SEH, it would be important to be able to identify those patients at high risk of developing symptomatic lesions. In addition, to minimize any lasting disability, surgeons should be aware of the appropriate and timely management of patients, once SEH has occurred.

There are currently limited data available for identifying patients at high risk of developing postoperative SEH [7], [10], [11]. In addition, there is little concurrence among the available studies.

The purpose of this multicenter retrospective case control study was to add to the limited evidence available by estimating the incidence and identifying the risk factors for the development of symptomatic SEH after open spinal surgery. In addition, we set out to evaluate the timing for the development of neurologic signs and symptoms in the postoperative period and whether early evacuation of SEH would minimize patient's neurologic deficit at the time of discharge.