On lumbar spinal stenosis and disc herniation surgery

Sammanfattning: Patients with spinal stenosis and disc herniation are most common in spine surgery. Few population based studies of these patients have been made and no studies of their health related quality of life (HRQOL) by the EQ-5D has been published. The aim of this thesis is to analyse incidence, readmission, reoperation and mortality in Swedish patients operated on spinal stenosis or disc herniation in the lumbar spine during 19871999 and report the EQ-5D outcome data between 2001-2002. The spinal stenosis cohort and disc herniation cohorts consist of 10,494 and 25,247 patients and the final EQ-5D analysis of 230 and 263 patients. Information from the Swedish Hospital Discharge Register and the Swedish Death Register were linked to analyse the outcomes. A quality register study based on prospectively collected EQ-5D data from the National Swedish Registry for Lumbar Spine surgery was also performed. The mean annual incidence per 100,000 inhabitants of spinal stenosis and disc herniation surgery during the study period was 10 and 24, respectively. The mean age at surgery for spinal stenosis increased from 60 to 67 years but was constant at 42 years for disc herniation. The 30 day mortality rate was 3.5 and 0.5 per 1000 operations, respectively. The mortality rate declined despite ageing spinal stenosis patients. The length of stay after surgery was reduced to half. Patients operated on for spinal stenosis and disc herniation have a risk of being reoperated after one and ten years of 2-3 %, and 10- 11 %, respectively. The reoperation rate decreased over time. During the 13 years, 78 % of the disc herniation patients had only one hospitalisation (the operation). The risk of being readmitted was constant over time. Preoperatively the HRQOL was low, poorer than among previously reported for patients with stroke or depression. Patients operated on for spinal stenosis and disc herniation experienced an improved health related quality of life and their EQ5-D score increased from 0.29 to 0.70 and 0.36 to 0.64 one year after surgery. Four out of ten reported considerable improvement while a similar proportion of patients with high preoperative scores were slightly improved. A third group (20 %) was unchanged with low EQ-5D scores, and 45% perceived a decline in their HRQOL. The majority of patients approached but did not reach the level reported by the matched population sample. The studies indicate factors such as male sex, age over 80, fusion procedure, smoking, hospital stays before surgery or long hospital stays at surgery, severe back pain, long duration of pain, short walking ability were risks for a less favourable outcome. The EQ-5D instrument increases the awareness of the importance of health related quality of life when considering surgery and when evaluating treatment. Future studies need to elucidate the gender differences, impact of smoking cessation programs and the cost utility of spine surgery.