Patient-reported outcome of surgical treatment for lumbar spinal epidural lipomatosis.

BACKGROUND CONTEXT

Spinal epidural lipomatosis (SEL) is a rare condition characterized by an excessive accumulation of fat tissue in the spinal canal that can have a compressive effect, leading to clinical symptoms. This condition has a distinct pathology from spinal stenosis associated with degeneration of the intervertebral discs, ligaments, and facet joints. Several different conservative and surgical treatment strategies have been proposed for SEL, but its treatment remains controversial. There is a lack of evidence documenting the success of surgical decompression in SEL, and no previous studies have reported the postoperative outcome from the patient's perspective.

PURPOSE

The aim of the present study was to evaluate patient-rated outcome after surgical decompression in SEL.

STUDY DESIGN

A retrospective analysis of prospectively collected data was carried out.

PATIENT SAMPLE

A total of 22 patients (19 males; age: 68.2±9.9 years) who had undergone spine surgery for SEL were identified from our local Spine Surgery Outcomes Database, which includes a total of 10,028 spine surgeries recorded between 2005 and 2012. Inclusion criteria were epidural lipomatosis confirmed by preoperative magnetic resonance imaging (MRI) scans and subsequent decompression surgery without spinal fusion.

OUTCOME MEASURES

The Core Outcome Measures Index (COMI) was used to assess patient-rated outcome. The COMI includes the domains pain (separate 0-10 scales for back and leg pain), back-specific function, symptom-specific well-being, general quality of life (QOL), work disability, and social disability.

METHODS

The questionnaires were completed preoperatively and at 3, 12, and 24 months postoperatively. Surgical data were retrieved from the patient charts and from our local Spine Surgery Outcomes Database, which we operate in connection with the International Spine Tango Registry. Differences between pre- and postoperative scores were analyzed using paired t tests and repeated measures analysis of variance.

RESULTS

At 3-months follow-up, the COMI score and scores for leg pain and back pain had improved significantly compared with their preoperative values (p<.005). The mean decrease in COMI score after 3 months was 2.6±2.4 (range: -1.3 to 6.5) points: from 7.5±1.7 (range: 3.5-10) to 4.9±2.5 (range: 0.5-9.6). A total of 11 patients (50%) had an improvement of the COMI of more than the minimal clinically important change (MCIC) score of 2.2 points. The mean decrease in leg pain after 3 months was 2.4±3.5 (-5 to 10) points. Overall, 17 patients (77.3%) reported a reduced leg pain, 12 (54.6%) of whom by at least the MCIC score of 2 points. The significant reductions from baseline in COMI and leg and back pain scores were retained up to 2 years postoperatively (p<.02). The general QOL item of the COMI improved significantly after surgery (p<.0001). Over 80% of the cohort rated their preoperative QOL as bad (n=13) or very bad (n=5), whereas 3 months after surgery, only 7 patients rated their QOL as bad, and one as very bad (36%).

CONCLUSIONS

The present study is the first to demonstrate that surgical decompression is associated with a statistically significant improvement in patient-rated outcome scores in patients with symptomatic SEL, with a clinically relevant change occurring in approximately half of them. Surgical decompression hence represents a reasonable treatment option for SEL, although the reason behind the less good response in some patients needs further investigation.