Table 1

Input parameters used in the health economic model.

Parameters	Distribution	Base Case	Range	References
Annual transition probabilities
Well state
To index revision (LLIF)	Beta	0.0169	0.015–0.019	[14]
To adjacent revision (LLIF)	Beta	0.0088	0.008–0.010	[15]
To index revision (PLIF)	Beta	0.0203	0.018–0.022	[16]
To adjacent revision (PLIF)	Beta	0.0237	0.021–0.026	[17]
Index revision state
To well (LLIF)	Beta	0.0979	0.088–0.108	[14]
To adjacent revision (LLIF)	Beta	0.0088	0.008–0.010	[15]
To well (PLIF)	Beta	0.0203	0.018–0.022	[16]
To adjacent revision (PLIF)	Beta	0.0237	0.021–0.026	[17]
Adjacent revision state
To index revision (LLIF)	Beta	0.0005	0.0005–0.0006	[15], Expert opinion
To index revision (PLIF)	Beta	0.0006	0.0005–0.0007	[17], Expert opinion
Utilities
LLIF, Well (3 mo)	Beta	0.874	0.817–0.931	Primary data
LLIF, Complication (3 mo)	Beta	0.778	0.652–0.904	Primary data
LLIF, Well (12th mo)	Beta	0.874	0.817–0.931	Primary data
LLIF, Well (>12th mo)	Beta	0.854	0.705–0.907	Primary data
LLIF, Index revision (>12th mo)	Beta	0.671	0.604–0.738	[5]
LLIF, Adjacent revision (>12th mo)	Beta	0.703	0.633–0.773	[5]
PLIF, Well (3 mo)	Beta	0.886	0.857–0.915	Primary data
PLIF, Complication (3 mo)	Beta	0.870	0.821–0.919	Primary data
PLIF, Well (12th mo)	Beta	0.886	0.857–0.915	Primary data
PLIF, Well (>12th mo)	Beta	0.882	0.856–0.907	Primary data
PLIF, Index revision (>12th mo)	Beta	0.646	0.581–0.711	[5]
PLIF, Adjacent revision (>12th mo)	Beta	0.679	0.611–0.747	[5]
Costs of treatment, USD/y
Total cost of well (LLIF)	Gamma	175	157–192	Primary data
Total cost of index revision (LLIF)	Gamma	3,665	3,299–4,032	Primary data
Total cost of adjacent revision (LLIF)	Gamma	7,062	6,356–7,768	Primary data
Total cost of well (PLIF)	Gamma	175	157–192	Primary data
Total cost of index revision (PLIF)	Gamma	3,462	3,116–3,808	Primary data
Total cost of adjacent revision (PLIF)	Gamma	4,791	4,312–5,270	Primary data
PEEK (LLIF)	Gamma	1,713	1,542–1,885	Primary data
PEEK (PLIF)	Gamma	529	477–582	Primary data
Tricalcium phosphate	Gamma	140	126–154	Primary data
Posterior spinal screws (LLIF)	Gamma	1,544	1,390–1,699	Primary data
Posterior spinal screws (PLIF)	Gamma	800	720–880	Primary data
Direct non-medication costs, USD/visit
Food OPD	Gamma	13	13–13	[20]
Transportation	Gamma	64	64–65	[20]

Abbreviations: IPD, inpatient department; LLIF, lateral lumbar interbody fusion; OPD, outpatient department; PEEK, polyetheretherketone; PLIF, posterior lumbar interbody fusion.