Article Figures & Data
Figures
- Figure 1
Decision tree and Markov model. (A) A decision tree was constructed to divide patients into 4 groups: “well,” “complications,” “index revision,” and “death” based on the health status outcomes of each surgical treatment.. The filled circles indicate choice node, the squares indicate decision node, the triangles indicate endpoint node, the circled "M" indicates Markov model. (B) In the Markov model, patients could remain in the same disease state or move to another health state. Tp = transitional probability.
- Figure 2
Tornado diagram illustrates the results of a 1-way sensitivity analysis. Abbreviations: LLIF, lateral lumbar interbody fusion; PLIF, posterior lumbar interbody fusion; Tp1, transitional probability from well to index revision; Tp8, transitional probability from index revision to well.
- Figure 3
Multivariate probabilistic sensitivity analysis. The results are based on 1000 Monte Carlo simulations and are shown as a cost-effectiveness plane (A) and a cost-effectiveness acceptability curve (B). Abbreviations: IBG, iliac bone graft; LLIF, lateral lumbar interbody fusion; PLIF, posterior lumbar interbody fusion; QALY, quality-adjusted life year; TCP, tricalcium phosphate; WTP, willingness to pay.
Tables
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.
Characteristics LLIF
(n = 30)PLIF
(n = 50)P Gender, n (%) Men 9 (30) 18 (36) 0.633 Women 21 (70) 32 (64) Age, y, median (IQR) 59 (55, 63) 61 (51, 69) 0.598 Body mass index, kg/m2 25.34 ± 3. 88 25.21 ± 3.97 0.894 Underlying diseases, n (%) Hypertension 15 (50) 22 (44) Diabetes mellitus 6 (20) 9 (18) 0.319 Coronary artery disease 0 (0) 4 (8) Chronic kidney disease 3 (10) 2 (4) Diagnosis, n (%) Spinal stenosis 16 (53) 16 (32) Spondylolisthesis 9 (30) 32 (64) 0.007a Degenerative disc disease 5 (17) 2 (4) Level of spine, n (%) L2–L3 3 (10) 1 (2) L3–L4 4 (13) 3 (6) 0.006a L4–L5 23 (77) 32 (64) L5–S1 0 (0) 14 (28) Abbreviations: IQR, interquartile range; LLIF, lateral lumbar interbody fusion; PLIF, posterior lumbar interbody fusion.
↵a Significant at a P value of less than 0.05. Statistical analysis using the Student’s t test without pairing, Mann-Whitney U test, χ 2 test, and Fisher’s exact test.
- Table 3
Perioperative data, postoperative complications, fusion rate, and PEEK subsidence rate.
Characteristics LLIF
(n = 30)PLIF
(n = 50)P Estimate blood loss, mL, median (IQR) 200 (100, 250) 350 (200, 500) <0.001a Operative time, min, median (IQR) 215 (170, 291) 180 (150, 211) 0.007a Length of hospital stay, d, median (IQR) 6 (5, 9) 7 (6, 8) 0.437 Postoperative complications, n (%) 7 (23) 14 (28) 0.794 Hematoma 1 2 Electrolyte imbalance 3 2 Anemia 3 4 Dural tear 0 6 Proximal limb neuropathy, n (%) 8 (27) 0 (0) <0.001a Fusion rate, n (%) 25 (83.3) 42 (84) 0.937 PEEK subsidence rate, n (%) 14 (46.7) 10 (20) 0.022a Abbreviations: IQR, interquartile range; LLIF, lateral lumbar interbody fusion; PEEK, polyetheretherketone; PLIF, posterior lumbar interbody fusion.
↵a Significant at a P value of less than 0.05. Statistical analysis using the Mann-Whitney U test and Fisher’s exact test.
Parameters LLIF (n = 30) P PLIF (n = 50) P 2-y Comparison Preoperative 2 y Preoperative 2 y Lumbar lordosis (°) 38.33 ± 12.92 42.97 ± 13.42 0.015a 33.62 ± 12.35 37.08 ± 12.38 <0.001a 0.049a Foraminal height, mm 16.10 ± 2.92 19.30 ± 3.32 <0.001a 11.11 ± 3.27 13.30 ± 2.56 <0.001a <0.001a Disc height, mm 6.07 ± 2.968 11.33 ± 2.93 <0.001a 6.72 ± 2.35 9.53 ± 1.83 <0.001a 0.001a Abbreviations: LLIF, lateral lumbar interbody fusion; PLIF, posterior lumbar interbody fusion.
↵a Significant at a P value of less than 0.05. Statistical analysis using Student’s t test for both unpaired and paired t tests.
- Table 5
Utility, ODI, and EQ-VAS of LLIF and PLIF preoperatively and at the 2-year follow-up.
Parameters LLIF (n = 30) P PLIF (n = 50) P 2-y Comparison Preoperative 2 y Preoperative 2 y Utility 0.68 ± 0.20 0.86 ± 0.13 < 0.001a 0.66 ± 0.17 0.88 ± 0.09 < 0.001a 0.501 ODI 39.67 ± 22.62 22.54 ± 16.16 < 0.001a 39.49 ± 15.11 24.19 ± 10.77 < 0.001a 0.584 EQ-VAS 63.50 ± 17.28 77.33 ± 17.31 0.004a 64.70 ± 15.30 75.90 ± 15.11 < 0.001a 0.698 Abbreviations: EQ-VAS, EuroQol Visual Analog Scale; LLIF, lateral lumbar interbody fusion; ODI, Oswestry Disability Index; PLIF, posterior lumbar interbody fusion.
↵a Significant at a P value of less than 0.05. Statistical analysis using Student’s t test for both unpaired and paired t tests.
Type of Fusion Options Cost,
USDEffectiveness
(QALY)Incremental Cost, USD Incremental Effectiveness (QALY) Net Monetary Benefit, USD PLIF 16,500 14.61 LLIF 15,355 14.48 −1145 −0.13 539.76 Abbreviations: LLIF, lateral lumbar interbody fusion; PLIF, posterior lumbar interbody fusion; QALYs: quality-adjusted life-year.
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