Fibromyalgia in patients undergoing spinal arthrodesis: Is surgery beneficial?

2015

Background
Chronic pain from fibromyalgia(FM) can complicate treatment decisions in patients with spinal disorders. Surgical decompression and fusion for cervical myelopathy improved many symptoms previously attributed to FM.  The effect of FM on outcomes after thoracolumbar arthrodesis remains unknown.   

Purpose
Assess the impact of FM on outcomes following spinal arthrodesis across the spectrum of degenerative disease and deformity. 

Study Design
Retrospective review of prospective data

Patient Sample
>Consecutive surgical cohort of 883 adults (M-282, F-601) who underwent posterior spinal fusion(PSF) from 2002 – 2012 by 3 surgeons; Primary surgery–465, revision–418. Excluded: acute fractures, tumor, infection. 

Outcome Measures
Outcomes were recorded pre-op, 1 year, 2 years, and yearly thereafter for Visual Analog pain scores(VAS), Oswestry Disability Index(ODI), and pain medication use.            

Methods
Patients were divided into 2 groups: FM-(n=73) vs. no fibromyalgia controls(NFM-n=810).  Subgroups were divided by diagnosis:  Degenerative (n=569:spondy-279, stenosis with degen-290), Deformity (n=314: degen scoliosis-133, idiop scoliosis-81, degen kyphoscoliosis-42, other kyphosis-58).  Revision (418) and primary surgeries (465) were compared for degenerative and deformity groups. Mann Whitney, Wilcoxon signed rank test, t-test, and multivariate linear regression were used in analysis.

Results
Follow-up averaged 7 years (24-150 months).  There were no difference FM vs NFM for diagnoses, age, smoking, diabetes, or BMI. There were more prior fusions in FM (44% vs 17%), more prior laminectomies (29% vs 15%) in NFM group. Co-morbidities: FM group had more than double the NFM bowel or bladder dysfunction (30% vs 10%), rheumatologic diagnoses (11% vs 5%), circulatory disorders (30% vs 15%), gastrointestinal disorders (35% vs 15%), and depression (35% vs 8%). NFM group was more likely to have no co-morbidities (22% vs 1%). Surgery was similar for both groups. VAS and ODI were consistently worse in FM group (p<0.001); Both groups improved VAS with surgery (FM: Pre-7.4, 2yr-4.8, 5yr-5.6; NFM: Pre-6.3, 2yr-3.5, 5yr-4.1) for all diagnoses, primary surgery (FM:Pre-7.3, 2yr-4.7, 5yr-5.4; NFM: Pre-6.0, 2yr-2.9, 5yr-3.8) and revision (FM: Pre-7.5, 2yr-4.9, 5yr-5.8; NFM: Pre-6.5, 2yr-4.2, 5yr-4.6), compared to pre-op (p<0.001).  Pain medication use followed similar trends. Long-term gains were better maintained in the NFM group (p<0.05). ODI significantly improved (p<0.001) for both groups (FM: Pre-58.1, 2yr-42.0, 5yr-45.9; NFM: Pre-48.4, 2yr-29.6, 5yr-31.6), all diagnoses, primary surgery (FM: Pre- 54.9, 2yr-38.6, 5yr-33.6; NFM: Pre-52.6, 2yr-35.6, 5yr-36.2) and revision( FM: Pre-60.5, 2yr- 44.6, 5yr- 52.1; NFM:Pre-52.6, 2yr- 35.6, 5yr-36.2). FM primary degenerative group had 5 year ODI-28.5 despite VAS-5.5.  Complications were not different FM vs NFM.  BMI (p=0.049) and fibromyalgia (p=0.056) were both predictors of increased pain (VAS) at 2 years.  Fibromyalgia was a predictor of inferior function (ODI) at 2 years (p=0.0197). Pre-op pain and function were good predictors of pain and function on follow-up(p<0.001).

Conclusions
Though FM patients had more co-morbidities, pain, need for pain medication, and worse functional scores than NFM patients, surgical arthrodesis still significantly improved outcomes long-term without an increase in complications. Primary surgery for degenerative disease had the highest long-term function in FM patients.