Table 2.

Inclusion criteria and types of operation of included studies.

Authors	Inclusion Criteria	No. of Vertebral Levels	Types of Operation
			Decompression Alone	Decompression + Fusion
Austevoll 20202	Diagnosed both spinal stenosis and spondylolisthesis, and then operated with decompression or with decompression + fusion	1–2	Microdecompression with midline preservation	Instrumented fusion
Chan 20194	Diagnosed grade one spondylolisthesis, and then underwent posterior-only surgery at the index level of lumbar spondylolisthesis (decompression alone or fusion with or without decompression), or underwent single-segment surgery (single-level disc decompression [eg, L4 or L4–five decompressive laminectomy]) or a 2-level vertebral fusion (eg, L4–five posterior spinal fusion)	1	Laminectomy	Instrumented fusion
Försth 201316 a	Aged >50 y at the time of surgery, diagnosed spinal stenosis on 1–2 adjacent levels between L2 and L5, with or without spondylolisthesis, and then operated with decompression or with decompression + fusion	1–2	Decompression	Instrumented or noninstrumented fusion
Försth 20166 a	Aged between 50 and 80 y, diagnosed spinal stenosis on 1–2 adjacent levels between L2 and sacrum, with or without spondylolisthesis, symptomatic (pseudoclaudication in one or both legs and back pain [VAS > 30]) for >6 mo, and then operated with decompression or with decompression + fusion	1–2	Decompression	Instrumented or noninstrumented fusion
Ghogawala 20047	Aged between 50 and 81 y, diagnosed grade one spondylolisthesis, and then operated with decompression or with decompression + fusion	-	Decompression with aggressive facet-sparing technique	Posterolateral instrumented fusion
Ghogawala 20168	Aged between 50 and 81 y, diagnosed stable grade one spondylolisthesis with spinal stenosis, symptomatic (neurogenic claudication with or without lumbar radiculopathy), and then operated with decompression or with decompression + fusion	1	Complete laminectomy with partial removal of medial facet joint	Posterolateral instrumented fusion
Inose 20183	Diagnosed spinal stenosis on one level at the L4-5, with spondylolisthesis, and then operated with decompression or decompression + fusion or decompression + stabilization	1	Decompression	Posterolateral instrumented fusion with autogenous iliac bone graft and pedicle screw
Kim 20189	Diagnosed grade one spondylolisthesis at L4-5, symptomatic, and then operated with decompression or with decompression +fusion	-	Decompressive laminectomy, partial facetectomy, <50% of the inferior articular processes in the transverse dimension, foraminotomy according to the extent of radiculopathy, with both facet joints preserved	Circumferential fusion with pedicle screws, posterolateral fusion with autogenous iliac bone graft, and posterior lumbar interbody fusion using a titanium cage filled with a local bone graft
Kleinstueck 201110	Diagnosed spondylolisthesis with a maximum of 3 levels affected, and then operated with decompression or with decompression + fusion	1–3	Decompression	Instrumented fusion
Matsudaira 200511	Diagnosed both spinal stenosis and spondylolisthesis on single level at L4/5, and then operated with decompression or with decompression + fusion	1	Laminoplasty to preserve the integrity of midline structure	Posterolateral fusion and pedicle screw instrumentation
Park 201212	Diagnosed stable grade one spondylolisthesis, and then operated with decompression or with decompression + fusion	1	Laminectomy	Instrumented fusion
Sigmundsson 201513	Diagnosed both spinal stenosis and spondylolisthesis on single level, and then operated with decompression or with decompression + fusion	1	Decompression	Posterolateral instrumented fusion
Ulrich 201715	Diagnosed both spinal stenosis and spondylolisthesis, and then operated with decompression or with decompression + fusion	1–2	Standard open or microscopic decompression of the lateral recess and the foramina	Implantation of pedicle screws with rods and intersomatic fusion and cage(s) at the affected level(s)

aOnly patients with spondylolisthesis were included in the analysis.