Researchers at Vanderbilt University Medical Center in Nashville, USA, found out that transforaminal lumbar interbody fusion is a cost-effective treatment option for patients with back and leg pain associated with grade 1 degenerative spondylolisthesis, however, for patients primarily with back pain and minimal leg pain, the same treatment may be less cost-effective. The results of the study, Cost Effectiveness of Transforaminal Lumbar Inter-Body Fusion (TLIF) for Grade I Degenerative Spondylolisthesis, were presented by Matthew J McGirt and Scott L Parker during the 79th Annual Scientific Meeting of the American Association of Neurological Surgeons, Denver, USA.
According to the American Association of Neurological Surgeons, low back and leg pain secondary to spondylolisthesis is occurring with increasing frequency, concurrent with the rising population of people age 65 and older living in the USA. As a result, there has been a marked increase in the rate of spinal fusion operations and corresponding healthcare costs over the past two decades.
The transforaminal lumbar interbody fusion procedure may assist in strengthening and stabilising the spine and may thereby help to alleviate severe and chronic back and leg pain. “Although it is clear that healthcare costs associated with spinal fusion procedures have increased, the cost effectiveness of transforaminal lumbar interbody fusion has not been elucidated conclusively in prior studies,” stated McGirt and Parker.
Pain, disability, and overall health were assessed pre-operatively and two years postoperatively utilising outcome questionnaires completed either during clinic evaluation or via phone interview. Patient-assessed questionnaires included an 11 point (0-10) Visual Analogue Scale (VAS) for low back pain and leg pain; Oswestry Disability Index (ODI) disability questionnaire; and EuroQol-5D (EQ-5D) quality of life questionnaire. The EQ-5D questionnaire was used to calculate the quality adjusted life years (QALY) associated with transforaminal lumbar interbody fusion. QALY is a measure of disease burden and includes both the quality of life and the quantity of life lived. When combined with cost data, it can be used to assess the value of a medical intervention.
Medical resource utilisation was assessed over a two-year period postsurgery. Direct costs consisted of doctor visits, diagnostic tests, emergency room visits, medications, and physical therapy. The indirect costs were estimated by assessing the productivity losses due to spine-related problems such as missed workdays for those employed outside the home. The following outcome and cost effectiveness results were noted:
– All two-year patient-assessed outcomes assessed were significantly improved from pre-operative levels. Two years postsurgery, the mean change in back pain and leg pain from baseline was 4.3 and 3.8 points, respectively.
– Patients reported significantly less disability and improved quality of life as assessed by the questionnaires. The cumulative health utility value gained over a two-year interval after transforaminal lumbar interbody fusion was 0.86 QALY.
– Mean two-year direct medical cost of transforaminal lumbar interbody fusion was US$25,251.
– Mean surgical cost was US$21,311 +/- 2086 and mean outpatient resource cost was US$3940 +/- 2720.
– Median reported annual income prior to surgery was US$50,000. There was a median of 60 missed work days. This represents a mean two-year indirect societal cost of US$11,584.
– The mean total two-year cost of transforaminal lumbar interbody fusion was US$36,835 +/- 11,800.
– At two years postsurgery, the total cost per QALY gained of TLIF was US$42,854.
“The cost per QALY gained is under the well accepted US$50,000 cost-effective threshold, suggesting that transforaminal lumbar interbody fusion is a cost-effective treatment option for patients with back and leg pain associated with grade 1 degenerative spondylolisthesis,” said Parker. “Transforaminal lumbar interbody fusion for patients primarily with back pain and minimal leg pain may be less cost-effective. Patient selection and surgical indication correlates closely with the procedure’s efficacy and cost effectiveness and should be considered carefully,” concluded McGirt.
Patient inclusion criteria
– MRI evidence of grade I degenerative lumbar spondylolisthesis
– Mechanical low-back pain and radicular symptoms
– Failed at least 6 months of conservative therapy
– Ages 18 to 70
Patient exclusion criteria
– History of a previous back operation
– Extra-spinal cause of back pain or sciatica
– Active medical or workman’s compensation lawsuit
– Pre-existing spinal pathology of any kind
– Unwilling or unable to participate with follow-up procedures
– Notable associated abnormalities; such as inflammatory arthritis, or metabolic bone
Co-authors of the study are Owoicho Adogwa, Alexandra Paul, Brandon Davis, Oran Aaronson, Clint Devon, and Joseph Cheng.