Table 2

Types of RSS performed for IL-RSS and AL-RSS.

RSS Group and Subgroup	Anterior RSS	Posterior RSS
IL-RSS (n = 16)	2	14
FA	None	7 total 6 PSF at IL 1 PSF at L4-L5 IL, plus extension to pelvis^{^a}
Migration	None	2 PSF at IL
FA + migration	2 r/o TDR+ ALIF (RRPA) 1 r/o L5-S1 TDR+ ALIF, + PSF L3-S1^{^a}	1 PSF at IL
Subsidence	None	3 PSF at IL
r/o IDSD	N/A	1 PSF at IL

AL-RSS (n = 18)	14	4
IL TDR at L4-L5	5 total 4 ALIF at L5-S1 (RRPA) 1 TDR at L3-L4 (LrRPA)	3 total 1 discectomy at L5-S1 1 PSF at L5-S1 1 PSF at L4-L5 IL, plus extension to pelvis^{^a}
IL TDR at L5-S1	9 total 1 ALIF at S1-S2 (LrRPA) 8 TDR at L4-L5 (LrRPA)	1 posterior 1 r/o L5-S1 TDR+ ALIF, plus PSF L3-S1^{^a}

Abbreviations: AL, adjacent level; ALIF, anterior lumbar interbody fusion; FA, facet arthropathy; IDSD, interspinous dynamic stabilization device; IL, index level; LrRPA, left revision retroperitoneal approach; PSF, posterior spinal fusion; r/o, removal of; RRPA, right retroperitoneal approach; RSS, revision spine surgery; TDR, total disc replacement;
↵a Patients underwent both AL-RSS and IL-RSS.