Table 2. Baseline characteristic of the 12 included studies.

Code	Title	First author	Study design	Study population	Age (mean ± SD)	Surgery method	Follow-up (y)	Outcomes
1	Lumbar spinal stenosis: Which predictive factors of favorable functional results after decompressive laminectomy	E. Foulongne	Prospective cohort	98 (94 M, 4 F)	67.3 ± 8.8	Decompressive laminectomy in lumbar stenosis	5	Walking distance, reoperation rate, complication
2	Long-term follow-up of revision decompressive lumbar spinal surgery in elderly patients	Shay Shabat	Retrospective cohort	31	> 65	Lumbar decompressive spinal surgery	10	Pain, reoperation rate, patient's satisfaction
3	5-year reoperation rates after different types of lumbar spine surgery	Alex D. Malter	Population-based cohort study	6,376 (3,764 M, 2,612 F)	48	Lumbar surgery	5	Reoperation rate, complication
4	Minimum 10-year outcome of decompressive laminectomy for degenerative lumbar spinal stenosis	Tetsuhiro Iguchi	Retrospective cohort	151	60	Decompressive laminectomy	10	Back pain, leg pain, neurogenic claudication, patient's satisfaction, multilevel laminectomy
5	Reoperation rate after surgery for lumbar spinal stenosis without spondylolisthesis: a nationwide cohort study	Chi Heon Kim	Retrospective cohort	8,795 (55.6 F, 44.4 M)	56.7 ± 12.1	Decompression without fusion (laminectomy and/or discectomy)	6	Reoperation rate, complication
6	Short-term and long-term revision rates after lumbar spine discectomy versus laminectomy: a population-based cohort study	Feng-Chen Kao	Retrospective cohort	66,754 (47.88 F, 52.11 M)	59.91 ± 14.02	Laminectomy	5	Reoperation rate
7	Factors influencing the outcome of operative treatment for lumbar spinal stenosis	M.U. Lehto	Retrospective cohort	96 (50 M, 46 F)	59	Laminectomy	5.5	Satisfaction, multilevel laminectomy, complication
8	The effect of surgical and nonsurgical treatment on longitudinal outcomes of lumbar spinal stenosis over 10 years	Yuchiao Chang	Prospective observational cohort	144 (54 M, 90 F)	65	LSS	10	Pain, disability, reoperation rate, patient's satisfaction
9	Five-year outcome of surgical decompression of the lumbar spine without fusion	Anne F. Mannion	Prospective cohort	143 (92 M, 51 F)	64	Lumbar decompression surgery without fusion	5	Leg pain and back pain intensity, self-rated disability, reoperation rates
10	Long-term outcomes of lumbar spinal stenosis: 8-year results of the spine patient outcomes research trial (sport)	Jon D. Lurie	Randomized trial with a concurrent observational cohort study	654 (385 M, 249 F)	64	Decompressive laminectomy	8	Patient's satisfaction, reoperation rate, complication
11	Clinical and radiological outcomes following microscopic decompression utilizing tubular retractor or conventional microscopic decompression in lumbar spinal stenosis with a minimum of 10-year follow-up	Gun Woo Lee	Retrospective cohort	102	56	Lumbar spinal stenosis	10	Pain, disability, walking distance, reoperation rate
12	Long-term outcomes of surgical and nonsurgical management of lumbar spinal stenosis	Steven J. Atlas	Prospective observational cohort	148	65	LSS	10	Patient-reported symptoms of leg and back pain, disability, reoperation rate, patient's satisfaction

Abbreviations: F, female; LLS, lumbar spinal stenosis; M, male; SD, standard deviation.