A recent study found that low back pain is significantly improved in 74% of patients immediately after surgery for lumbar spinal stenosis and that at two years, over two-thirds of patients continue to have significant relief of low back pain (LBP) symptoms. Shreya Srinivas (Alder Hey Children’s Hospital, Liverpool, UK) recently presented these results at the 2019 meeting of the British Association of Spine Surgeons (BASS; 3–5 April, Brighton, UK).
Srinivas and colleagues (CSORN Investigators, Canadian Spine Society) found that various patient factors, including the absence of claims or compensation, baseline severity of LBP and the absence of narcotic usage, to be associated with LBP improvement however, found no significant correlation between the type of surgical procedure performed and LBP improvement.
Lumbar spinal stenosis is the most common indication for lumbar spine surgery in older adults. While the predominant presenting symptom is of neurogenic claudication, LBP is a common associated or coexisting presenting symptom that contributes to disability. According to the authors, there is substantial high quality evidence that surgical intervention results in good relief of leg pain, and therefore an improvement in functional and disability status however, improvement in back pain relief as a primary outcome measure has not been investigated so far.
The investigators describe the study as a multicentre, retrospective review of consecutive spine surgery patients enrolled by the Canadian Spine Outcomes and Research Network (CSORN) between 2014 and 2017. The aim was to assess quality improvement of LBP following surgical decompression for lumbar canal stenosis, and also to identify factors associated with a change in LBP.
Patients undergoing surgical treatment for lumbar spinal stenosis without instability were included, with the surgical intervention (either decompression with or without fusion, conducted using either an open or minimally invasive approach) being left to the discretion of the treating surgeon.
Postoperatively, the investigators recorded patient-reported outcome measures (PROMs), with baseline PROMs repeated for those waiting longer than six weeks prior to surgery. This information was collected in person, via post or by employing an online portal at baseline, three months, 12 months and 24 months.
Outcome measures included patient variables, specifically socio-demographic factors, medication and resource utilisation, comorbidities and symptoms. Operative and postoperative variables, such as type of procedure, operating time, blood loss, adverse events and length of hospital stay were also collected, as well as patient-reported outcomes, from a disability scale, numerical rating scale (NRS) for back and leg pain, the EuroQol EG5D and the SF-12 physical (PCS) and mental component summary (MCS). The investigators note that they considered a change in NRS of two points to count as a minimal clinically important difference.
Out of the 1,221 patients included in the CSORN registry study, the mean age was 63.9 years (25–90) and the number of male patients included was 711 (58.2%), compared to 510 female patients (41.8%). Two hundred and eleven patients replied yes to being a smoker (17.3%), while 921 (75.4%) replied no and the mean BMI of the patient cohort was 29 (15–60). The mean score from the EQ-5D was 0.54 (-0.11 to -1). Two hundred and seventy-five patients stated that they were employed (58.4%), compared to 196 who said they not employed (41.6%). For 27 of the patients the duration of their back pain lasted between 0–3 months, for 150 patients it lasted between 3–12 months, 138 patients for 10–2 years, 325 patients for over two years and for 10 patients the duration of their back pain was not known.
Six hundred and seventeen patients (72%) were treated with either discectomy or decompression, 227 (26.6%) were treated with fusion with discectomy or decompression, and for eight patients the surgical procedure was unknown. In terms of surgical approach, 357 patients underwent minimally invasive surgery (MIS), while a majority of 495 patients underwent open surgery. The average surgical time was 117.64 minutes (30–800) and the average length of hospital stay was 3.9 days (0–371). Adverse events occurred intraoperatively in 70 patients (8.2%), perioperative in 109 patients (13.2%) and postoperatively in 55 patients (10.6%).