Predictive Factors for LBP Interventional Treatment Outcomes

Overview

In this study, we are attempting to determine which factors are associated with interventional treatment outcome for LBP (and to what extent). Up to 346 patients with LBP who are considered to be good candidates for therapeutic interventional procedures will be given a complete history and physical exam, which includes the assessment of Waddell signs, and querying them regarding factors shown in non-interventional studies or retrospective studies evaluating interventional treatments to be associated with negative treatment outcomes. These factors include the presence of Waddell and other physical exam signs, opioid use, allergies, psychopathology, concomitant pain conditions, a 6-point Likert scale on expectations, sleep abnormalities, secondary gain (e.g. medical board or litigation), procedure-related pain including from a 1 ml standardized injection, obesity, and smoking history. They will then proceed to undergo their scheduled intervention, which will be limited to epidural steroid injections (ESI), facet blocks and if positive, radiofrequency denervation, and sacroiliac (SI) joint injections. A positive outcome will be defined as 2-point or greater decrease in average pain score at 1-month and a score of \> 3 on a 1-5 Likert satisfaction scale. Those with a positive outcome at 1-month will remain in the study and be followed again at 3-months.

This will be an observational study with a 3-month follow-up. The course of clinical treatment will be decided by a physician independent of the research. Besides filling out questionnaires and standardized follow-up visits, all subjects will receive the same care they would if they did not participate in the study. The study will be discussed with the subjects and they will be enrolled in the study after it is determined that they meet selection criteria and are scheduled for one of the above injections. They will then fill out 3 questionnaires (Oswestery disability index, Athens insomnia scale, QIDS SR-16. All procedures will be performed with fluoroscopy. Following each procedure, the procedure-related pain will be reported on a 0-10 scale (all patients will receive as much 1% lidocaine local anesthetic as is necessary), including the reported pain to the standardized skin wheal at the start of the procedure. Patients will then receive standardized epidural steroid injections (transforaminal or interlaminar), sacroiliac joint injections, or facet blocks and radiofrequency denervation if they experience a positive block. Details about these procedures are available upon request. No patients will be permitted additional interventions between the time of their procedure and follow-up visits. Rescue medications will be in the form of either tramadol, NSAIDs or if the patient is on opioids, a \< 20% increase in dose. The first follow-up visit will be scheduled 1 month from the start of treatment for ESI and SI joint patients, and 1 month after RF denervation in positive diagnostic facet block responders. In those facet block patients who obtain prolonged relief from the "diagnostic" medial branch block, follow-up will be 1 month after the block (these patients may proceed to have denervation if their pain recurs after 1 month but before their final 3-month follow-up, and their 3-month follow-up will be 3 months after their medial branch block). A positive outcome will be defined as a greater or equal to 2-point decrease in average LBP (or leg pain for those who underwent an ESI) coupled with a positive satisfaction rating (\> 3 on a 5-point scale). Subjects who obtain a positive outcome at their initial 1-month follow-up visit will remain in the study and return for the final 3-month follow-up visit. Those with a negative outcome will exit the study "per protocol" to receive standard care, which may consist of other injections or non-rescue medications such as antidepressants and anticonvulsants. Subjects who obtain a positive outcome at 1-month but experience a recurrence before their 3-month follow-up visit will also exit the study per protocol, with their final outcome measures recorded before they receive standard care. In those who receive ESI, a smaller parallel study will be done evaluating the association between allergies and outcome. Allergies will be categorized as immunologically based or not.