External Review and Validation of a Spinal Epidural Abscess Predictive Score for Clinical Failure

Spinal epidural abscess (SEA) is a rare but serious pathology that may result in delayed neurologic injury despite treatment with antibiotic therapy or surgery. Given this, the development of predictive scores for risk stratification has value in clinical decision making; however, external validation is necessary to understand their generalizability and reliability.

A retrospective review was conducted of all patients presenting with SEA at a single institution. Patients were reviewed and graded according to the proposed SEA predictive score by Baum et al. Clinical failure was defined as documented laboratory or radiographic progression requiring surgical intervention, increased deformity requiring surgical intervention, or repeat surgical intervention if prior surgical intervention was undertaken as the initial treatment strategy. Brier score and receiver operating characteristic were used to calculate reliability.

There were 224 patients presenting with primary spinal infections with associated SEA. Of these, 209 patients had no history of intravenous drug abuse. Clinical failure was demonstrated in 52 of 209 patients (24.9%). Antibiotic treatment alone compared with antibiotic therapy and surgical treatment on initial presentation was found to have a significantly greater chance of clinical failure (odds ratio = 3.0930, P = 0.01). The proposed epidural abscess prediction score did not correlate with clinical outcomes with a Brier score of 0.229 and receiver operating characteristic area under the curve of 0.5944.

The proposed risk stratification scale for patients was not correlated with risk of clinical failure. Additionally, patients treated with antibiotics and surgical intervention on initial presentation had a significantly lower clinical failure rate.