Cost-effectiveness of Small Size Interarcuair Decompression Versus Extended Decompression in Patients With Intermittent Neurogenic Claudication (Size)

Cost-effectiveness of Small Size Interarcuair Decompression Versus Extended Decompression in Patients With Intermittent Neurogenic Claudication

Cost-effectiveness of Small Size Interarcuair Decompression Versus Extended Decompression in Patients With Intermittent Neurogenic Claudication (Size-study): a Multi-center, Double-blinded Randomized Controlled Trial

Rationale: Minimally invasive techniques have gained popularity to decompress lumbar spinal stenosis in the elderly. However, high quality evidence based on randomised controlled trials are not available. Objective: To investigate whether small size interarcuair decompression is more effective than conventional laminectomy in patients with intermittent neurogenic claudication caused by lumbar spinal stenosis. Study design: Double-blinded multi-centre randomised controlled trial Study population: In total 236 patients are to be included. The inclusion criteria are: subjects > 40 years of age with at least 12 weeks of complaints of intermittent neurogenic claudication based on MRI confirmed of LSS, with sufficient knowledge of the Dutch language. Intervention: Small size interarcuair decompression versus conventional laminectomy. Main study parameters/endpoints: Primary outcome is the Modified Roland Morris Questionnaire. Secondary outcomes are leg pain, back pain and a 6 minute walk test amongst others. Nature and extent of the burden and risks associated with participation: based on available literature , it is believed that the risks associated with small size interarcuair decompression are no greater than that associated with a laminectomy, although these will be examined.

Intermittent neurogenic claudication (INC) caused by a lumbar spinal canal stenosis (LSS) is the most frequent reason for spinal surgery in the elderly. Multiple, less invasive surgical techniques are applied without sufficient evidence for benefits for patients or society. The classic symptoms of INC are leg pain, which can be exacerbated with prolonged walking and standing and/or lumbar extension, and is associated with back pain. Severe stenosis is common in the elderly spine with 30.4% of the population having severe stenosis. However, only 17.5% have complaints of INC. Conservative treatment, such as physical therapy or pain medication, may give some relief of symptoms. However, surgical treatment is considered to be the gold standard for patients with INC caused by LSS. The first technique ever described to widen the lumbar spinal canal is the wide bony decompression (laminectomy), which is still a widely used technique. However, since INC is often accompanied by back pain, and this to post-operative back pain, it is hypothesized that a wide decompression is a ground for potential instability. Hence, less invasive techniques, such as interarcuair decompression, were developed and implemented. Recent studies claim that a limited bony decompression is the new 'golden standard' therapy for patients with INC. Limited bony decompression is believed to give less muscle damage and thus a faster postoperative recovery. Furthermore, wide bony decompression (such as a laminectomy) is believed to result in lumbar instability and iatrogenic scoliosis. Performing a procedure with potential more complications in a - generally - elderly population could at least be described as doubtful. The assumption is often made that after a wide decompression recurrence of the complaints must be scarce. However, a (cost-) effectiveness study, which evaluates the effectiveness of small bony decompression compared to a 'classical' extensive bony decompression, has not been performed yet. The opinions on this matter are diverse. A laminectomy involves the removal of more bone and structures at the back of the spine which may result in longer hospitalization and loss of productivity, but it could also lead to spinal instability on the long term. However, the risk of an insufficient decompression may be higher, potentially leading to more reoperations. By the means of this double-blinded, multi-center randomized controlled trial the investigators will determine the (cost-) effectiveness of a limited bony decompression compared to a wide bony decompression in patients with INC.

A median lumbar incision is made and the paravertebral muscles are dissected subperiosteally and retracted unilaterally or bilaterally. Decompression will be applied via decompression of the ligamentum flavum. The lateral recess will be opened bilaterally and a medial facetectomy will be performed in order maintain stability of the segments. Posterior ligaments will be spared. The wound will be closed in layers with or without a suction drain. Patients will be operated with a loupe magnification or microscope depending on the surgeon's preference.

A median lumbar incision is made over the spinous processes, the laminae of the affected level(s) are exposed subperiosteally, and the supraspinous ligament will be incised. The spinous process is removed. The supra and interspinous ligament of the affected level is removed by drill or Kerrison punches. The lamen is removed of the affect level, leaving the facet joint intact. The lateral recess will be opened bilaterally and medial facetectomy will be performed in order to maintain stability of the segments. When a single level stenosis is present (e.g. L4-L5) both laminae L4 and L5 will be removed. The wound will be closed in layers with or without a suction drain. Patients will be operated with loupe magnification or microscope depending surgeon's preference.

This is a 24-point Dutch questionnaire that is designed to assess the physical disability in patients, due to lower back pain.

baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

The ODI is one of the principal condition-specific outcome measures used in the management of spinal disorders.

baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

A functional X-ray will be obtained from all patients X-ray will be made from AP and lateral position to assess spondylolisthesis. Degenerative spondylilolisthesis is defined as a vertebral slip of at least 3 mm.

o measure the perceived recovery a seven-point Likert scale will be used. The score on this scale vary from 'completely recovered' to 'worse than ever'.

3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

To measure patient satisfaction a seven-point Likert scale will be used. The score on this scale vary from 'completely satisfied with current symptoms' to 'completely dissatisfied with current symptoms'.

3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

The SF-36 will be used as a generic quality-of-life questionnaire. The SF-36 questionnaire has been validated and found reliable for low back pain.

Baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

A systematic assessment of complications (including wound infection, deep venous thrombosis, urine tract infection, hematoma, and progressive neurological deficit) will be recorded out by the surgeon and research nurse, and these data are to be extracted from the patient chart. Moreover, surgeons will be asked for perioperative complications

3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

The EuroQoL (EQ-5D) will be used for the cost utility analysis. The tool measures five dimensions: mobility, self-care, daily activities, pain/discomfort, and anxiety/depression. Each dimension consists of one item, while five levels are distinguished (no, slight, moderate, severe problems, unable to do)

Baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

Cost questionnaires will be completed at the prescribed measurements. Hospitalisation for surgery will be registered using the case record forms. Other health care utilization (including physiotherapy, visits to GP and specialists, nursing care and medication), patient costs, and absenteeism from work will be measured using cost questionnaires filled out by the patients.

Baseline, 3 weeks, 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, 36 months and 48 months after surgery

Inclusion Criteria: At least 12 weeks of complaints of INC Magnetic resonance imaging showing LSS Age >40 years of age Sufficient knowledge of the Dutch language Signed informed consent Exclusion Criteria: History of lumbar spine surgery >2 lumbar levels operation or needed discectomy Degenerative spondylolisthesis > grade 1 (on a scale of 1 to 4), scoliosis or disc herniation ASA-classification >3 Serious psychopathology Pregnancy Active malignancy Plans to move abroad during study period

After final publication of manuscript the data set will be available from the authors or journal of publication. Anonymized clinical data will be available.

Arjun Sharma J, Gadjradj PS, Peul WC, van Tulder MW, Moojen WA, Harhangi BS; SIZE-study group. SIZE study: study protocol of a multicentre, randomised controlled trial to compare the effectiveness of an interarcuair decompression versus extended decompression in patients with intermittent neurogenic claudication caused by lumbar spinal stenosis. BMJ Open. 2020 Oct 6;10(10):e036818. doi: 10.1136/bmjopen-2020-036818.