Evidence-based Spinal Fusion
- Class I: used to support treatment recommendations of the strongest type, reflecting a high degree of clinical certainty.
- Class II: used to support recommendations called guidelines, reflecting a moderate degree of clinical certainty.
- Class III: other sources of information, including case series, expert opinion and flawed randomized controlled trials, support practice options reflecting unclear clinical certainty.
Example 1: Fusion in Patients with Stenosis and Spondylolisthesis
In one section of Guidelines, the authors looked at whether fusion should be used for patients with stenosis (a narrowing of the spinal column) and associated degenerative spondylolisthesis (when a vertebra slips forward).
In their research, the authors found 85 published cases "that provided either direct or supporting evidence relevant to the use of fusion for degenerative lumbar spondylolisthesis." More patients reported positive outcomes when fusion was combined with decompression treatments compared with patients who only underwent decompression treatments (without spinal fusion).
A convincing amount of evidence from all three classes allowed the authors to conclude that "the best medical evidence available in the literature confirms the utility of fusion for improving patient outcomes following decompression for stenosis associated with spondylolisthesis."
Example 2: Herniated Disc Excision
In one section of the 17-part study, authors examined literature to determine whether spinal fusion should be used to address radicular (nerve) pain due to herniated disc excision (removal). They found "no convincing medical evidence to support" the use of lumbar fusion during disc removal because of "conflicting Class III medical evidence regarding the potential benefit."
In short, the evidence the authors reviewed allowed them recommend neither a treatment standard or treatment guideline, because the Class III evidence is the least reliable according to their standards and, in this case, contradictary.
The study results have a dual purpose: (1) to identify whether the proper treatment course for certain spinal disorders should include spinal fusion, based on the current evidence, and (2) to spur further study and research in an attempt to more solidly establish consistent guidelines for treatment.