Spinal Epidural Abscess—Is Drainage Required?

Abstract & Commentary

Synopsis: In this small, retrospective analysis, surgical drainage of epidural abscesses was not associated with improved outcomes, even in patients who presented with neurological deficits.

Source: Siddiq F, et al. Medical vs Surgical Management of Spinal Epidural Abscess. Arch Intern Med. 2004;164:2409-2414.

Siddiq et al reviewed the management of 60 episodes of spinal epidural abscess in 57 patients seen over 14 years, ending in 2002. The lumbar or lumbosacral region was involved in 54%, the thoracic in 18%, and the cervical in 28%. The number of vertebral levels involved was 1-8, with more than 2 vertebral levels involved in 45% of patients.

Blood cultures were positive in 26 (46%) patients, and abscess cultures were positive in 36 (63%). Staphylococcus aureus was recovered from 34 patients (60%), coagulase negative staphylococci from 5 (9%), streptococci from 9 (16%), Enterococcus faecalis from 3 (5%), Actinomycetes from 4 (7%), and other organisms from 8 (18%).

All patients received antibiotic therapy. Surgical decompression was performed in the management of 28 (47%) of episodes, and CT-guided percutaneous needle aspiration in 7 (12%), while medical management alone was administered in 25 (42%) of episodes.

Neurologic impairment was present at presentation of approximately half of all episodes, and was marked in 11. Complete recovery was achieved in 43 (72%) episodes, while an additional 10 (17%) were left with only minimal residual weakness. Recovery rates were similar regardless of the management mode. Only neurologic impairment at presentation was associated with a poor outcome. Complete recovery was achieved in only 17 of 30 (57%), with impairment at the outset of therapy, compared with 93% in those without initial impairment. Even in those 3with neurological complications at presentation, there was no significant difference noted in outcomes when surgical and non-surgical management were compared.

Comment by Stan Deresinski, MD, FACP

The management of spinal epidural abscess has evolved over the last 2 decades, with the most important change being the recognition that not all patients require surgery for a successful outcome. The most generally agreed upon approach has been to intervene surgically only in patients with a neurological deficit resulting from the infection. Thus, patients presenting with a deficit as the consequence of cord compression are referred for urgent decompression. Those without an initial deficit are examined carefully several times daily for evidence of its appearance, an event that triggers referral for a decompressive procedure. In any case, antibiotic therapy is prolonged, although the duration is somewhat arbitrary, since there is no good clinical evidence upon which to base a recommendation regarding duration. The necessary duration of therapy, however, is likely to be longer in cases in which osteomyelitis and/or diskitis are present than when they are absent.

The mode of decompression has also evolved with the recognition that many spinal epidural abscesses can be successfully drained using percutaneous CT-guided aspiration.1 This procedure was, in fact, used successfully in 7 of 7 episodes in this series. When successful, this mode of decompression, as well as of specimen acquisition for microbiological studies, has an obvious advantage over surgical decompression.

Accepting the implications of the report by Siddiq and colleagues at face value would, however, indicate that the approach to management described above results in unnecessary surgery in many patients. Siddiq and colleagues conclude that surgery is not required in most instances, even in patients presenting with a neurological complication of the infection. On the other hand, clinical experience has led to observations of sometimes apparently dramatic results from decompression, including the resolution of tetraplegia in some patients with epidural abscess involving the cervical spine.2 It must be recognized that not all spinal cord complications in patients with this problem are amenable to surgical intervention or to percutaneous aspiration, since myelopathy may result from compression and/or thrombosis of spinal vasculature in the absence of cord compression.3

The retrospective nature of this study, patient heterogeneity, and small sample size all contribute to a wariness concerning its conclusions. I continue to believe that patients who develop a neurological deficit as the result of cord compression should be considered candidates for decompression, especially if this can be achieved by percutaneous drainage. I also continue to believe that an important key to a successful outcome is early recognition of this infection, since delayed diagnosis is associated with increased risk of permanent neurological deficit.4

References

1. Lyu RK, et al. Spinal Epidural Abscess Successfully Treated With Percutaneous, Computed Tomography-Guided, Needle Aspiration and Parenteral Antibiotic Therapy: Case Report and Review of the Literature. Neurosurgery. 2002;51:509-512.

2. Young WF, et al. Reversal of Tetraplegia in Patients With Cervical Osteomyelitis—Epidural Abscess Using Anterior Debridement and Fusion. Spinal Cord. 2001; 39:538-540.

3. van de Warrenburg BP, et al. Myelopathy Due to Spinal Epidural Abscess Without Cord Compression: A Diagnostic Pitfall. Clin Neuropathol. 2004;23:102-106.

4. Davis DP, et al. The Clinical Presentation and Impact of Diagnostic Delays on Emergency Department Patients With Spinal Epidural Abscess. J Emerg Med. 2004;26:285-291.

Stan Deresinski, MD, FACP, Clinical Professor of Medicine, Stanford; Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, is Editor for Infectious Disease Alert.