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Evidence-based Spinal Fusion

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Spinal Surgery

UW Health neurosurgeon Daniel K. Resnick, MD, was the lead author of a work group of 11 physicians nationwide chosen to evaluate the efficacy of spinal fusion procedures to treat a number of various lumbar spine problems.

Dr. Resnick, who specializes in spinal tumors and degenerative disorders of the spine, collaborated with ten neurological and orthopedic surgeons for an exhaustive, two-year review of the vast and often times contradictory views of spinal fusion in the medical community.

Their findings were published in Guidelines for the Performance of Fusion Procedures for Degenerative Disease of the Lumbar Spine (hereafter referred to as Guidelines).

"Due to a lack of standardization, treatment strategies have been based on institutional, departmental, or personal experience, which has led to management philosophies that are not consistent," said Robert F. Heary, MD, chairman of the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section on Disorders of the Spine and Peripheral Nerves. "Reports in the available medical literature are inconsistent and vary widely in terms of scientific veracity."

The project's goal was to create a consistent, evidence-based evaluation of spinal fusion so physicians have a singular source to which they can turn when deciding whether the procedure is appropriate for their patients.

The Need for an Evidence-based Approach

The use of spinal fusion to treat spine disorders has increased markedly in the past two decades, spurred by significant technological and medical innovations. But this proliferation has also witnessed inconsistency in the use of the procedure, because the medical community had not reached a consensus about the conditions for which the spinal fusion is most effective.

As the authors note in Guidelines, "Lumbar fusion has been described as a treatment of symptomatic degenerative disc disease, spinal stenosis, spondylolisthesis, and degenerative scoliosis. Lumbar fusion has been performed to treat acute and chronic low back pain, radiculopathy and spinal instability."

But should it be used in all of those cases? That was the question the study hoped to answer.

Study Methodology

In their review of available literature, the study authors established three classes of evidence:

  • 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, contradictory.


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.


Dr. Resnick continues to work in the development of clinical practice guidelines in spinal surgery and has authored guidelines concerning the use of antibiotics in spinal surgery, the use of prophylactic measures for venous thromboembolic disease in spine surgery and the role of surgery in the management of lumbar stenosis.


A multidisciplinary guideline on the surgical and non-surgical management of lumbar spine disorders co-authored by Dr. Resnick was published in May of 2009, in the journal Spine. His most recent project, dealing with the natural history and surgical management of cervical myelopathy, was published in Journal of Neurosurgery: Spine in August of 2009.