Surgical treatment for degenerative spine conditions often includes lumbar fusion. Patients are selected carefully for this procedure. The surgeon relies on evidence-based studies to discuss a reasonable treatment plan with the patient.
Most patients expect a certain level of improvement in pain, motion, and/or function before they will consider surgery as an option. Studies have been done to determine what would be considered a minimum level of improvement that signals a successful operation.
In this study, threshold of success is defined and measured for quality-of-life (QOL) improvement. What is QOL and how much does it have to improve to represent a benefit of surgery? These are the questions addressed for patients having a lumbar spine fusion for degenerative spine disease.
Patients having a lumbar spine fusion filled out questionnaires before and after surgery. Four well-known health-related self-report survey tools were used. These included the Medical Outcomes Study Short Form-36 (SF-36), the Oswestry Disability Index (ODI), a back pain rating scale, and a leg pain rating scale. All of these instruments help show when there has been a measurable clinical benefit of surgery.
A satisfaction survey was another tool used to measure quality of life. Patients were asked to rate five statements on a continuum from definitely true to definitely false. Some examples of the statements were: I can do the things that I thought I would be able to do after surgery. All things considered, I would have the surgery again for the same condition.
Each answer was given a point value and the scores added up to assess the quality-of-life outcomes of spine surgery. Based on scores, values were given to five intervals. These included most satisfied, satisfied, unsure, dissatisfied, and most dissatisfied.
Change in quality-of-life score was calculated from before surgery to one-year after surgery. Three measures were calculated: total score, net improvement, and per cent improvement or change. Per cent of change was labeled as much better or about the same. Satisfaction was divided into mostly satisfied or unsure.
The authors conclude that there was a relationship between the change in health-related quality-of-life and benefit perceived by the patient. And the threshold value to determine when it was worth having the surgery could be determined using these various surveys. Specific scores for each survey are reported as thresholds of clinical benefit. These thresholds represent how much patients’ scores had to improve before the surgery was considered worth having.
The authors point out that patients with a low score for preoperative health status will look like they had a larger per cent change compared to patients who weren’t so bad off before the operation. And the study only looked at health-related quality-of-life scores at the end of one-year postoperatively. Results might look different if other time intervals (shorter or longer) were used.