Purpose of the study: In the literature, the frequency of postoperative compressive spinal epidural hematomas (SEH) appearing very low, we conducted the present study to determine the frequency of this complication in their unit and look for causative and predisposing factors.
Material and methods: Among the 1,487 spinal operations performed in our unit between September 1997 and August 1998, fifteen patients had postoperative compressive SEH; their files were retrospectively analyzed regarding the initial intervention, postoperative period, revision operation and neurologic follow-up.
Results: Five women and ten men were involved ranging in age from 47 to 70 years (average, 59.5 years). The primary intervention concerned the cervical spine in one case, the thoracic spine in seven and the lumbar spine in seven. Ten of the fifteen cases including all seven of the thoracic SEH (performed for compressive metastatic epiduritis) involved a laminectomy. A stenotic canal was the indication for the primary intervention in six of the seven lumbar cases. The average delay before onset of symptoms was 1.5 hours, 3.7 hours, and 5.3 hours after the cervical, thoracic, and lumbar interventions, respectively. The clinical pattern began with segmental pain rapidly followed first by bilateral radicular sensory deficit, then unilateral or bilateral motor deficit, except in the patients with thoracic SEH in whom segmental pain was followed by signs of cord impingement. Excluding the four cases in which diagnosis was retarded by work-up examinations (3 cases) or a misleading picture (1 case), revision surgery was performed from 1.25 to 4 hours after onset of symptoms (average, 2.75 hours). In the patients for whom reoperation was delayed, SEH resulted in permanent complete paralysis or sphincter dysfunction. In contrast, eight of the ten patients who were reoperated within four hours of the onset of symptoms either recovered completely or recovered their former neurologic status.
Discussion: Compressive SEH after spinal surgery is rare, only 41 cases having been reported aside from the series of Deburge et al. In the literature, the frequency is around 1 to 2 for 1000 operations for some authors, as opposed to 3 p. 100 and 6 p. 100 found by two other groups. The 1 p. 100 of the present series is close to the latter values. Nonetheless, it is probably important to take the type of surgery into account, as shown by the current series in which SEH occurred after 5.9 p. 100 of the operations for metastasis, but only once out of 304 anterior cervical interventions. To reduce the risk as much as possible, it is important to be aware of the factors that may contribute to this complication. Several recommendations concerning prevention of SEH are thus discussed. Once SEH has occurred, the only modifiable prognostic factor appears to be the delay before reintervention.
Conclusion: Although postoperative SEH is relatively rare, it may have dramatic consequences. In our opinion, reintervention must be performed as soon as possible after the onset of neurologic deficit, the work-up investigations only prolonging the critical surgical delay, which is probably the only alterable prognostic factor.