Table 3.
Adjusted Mean 2-Year Costs, Quality-Adjusted Life-Years (QALYs), and Cost per QALY Gained Relative to Nonoperative Treatment*
| Patient Group | Patients, n | Mean Cost (95% CI), $ | QALY (95% CI) | Cost <$100 000 per QALY Gained, %† | Cost per QALY Gained (95% CI), $‡ |
|---|---|---|---|---|---|
| Spinal stenosis | |||||
| Nonoperative | 240 | 13 519 (10 921 to 15 796) | 1.37 (1.33 to 1.40) | – | – |
| All surgery | 394 | 26 222 (24 308 to 28 129) | 1.54 (1.51 to 1.56) | 89 | 77 600 (49 600 to 120 000) |
| Type of surgery | |||||
| Decompression | 320 | 22 404 (21 132 to 23 709) | 1.54 (1.51 to 1.57) | 100 | 47 900 (28 200 to 73 600) |
| Fusion | 43 | 39 949 (33 626 to 46 292) | 1.53 (1.41 to 1.64) | 17 | 258 200 (70 700 to 710 700) |
| Degenerative spondylolisthesis with spinal stenosis | |||||
| Nonoperative | 233 | 16 046 (13 862 to 18 234) | 1.33 (1.30 to 1.36) | – | – |
| All surgery | 368 | 42 081 (39 800 to 44 373) | 1.55 (1.53 to 1.58) | 14 | 115 600 (90 800 to 144 900) |
| Type of surgery | |||||
| Decompression | 19 | 22 012 (10 860 to 34 647) | 1.53 (1.31 to 1.75) | 92 | 38 900 (−39 000 to 174 409) |
| Fusion | 344 | 42 979 (40 574 to 45 354) | 1.55 (1.53 to 1.58) | 8 | 120 200 (94 100 to 153 400) |
| Type of fusion surgery | |||||
| Noninstrumented fusion | 75 | 40 858 (36 004 to 45 651) | 1.54 (1.48 to 1.61) | 27 | 119 900 (72 200 to 192 000) |
| Instrumented fusion | 269 | 43 116 (40 343 to 46 018) | 1.56 (1.53 to 1.59) | 12 | 118 100 (91 200 to 153 100) |
| Type of instrumentation | |||||
| Posterolateral fusion (pedicle screws) | 209 | 42 562 (39 263 to 45 893) | 1.54 (1.50 to 1.58) | 10 | 121 400 (92 000 to 159 700) |
| Circumferential (360°) fusion§ | 60 | 46 970 (39 511 to 55 414) | 1.62 (1.54 to 1.70) | 43 | 107 000 (65 100 to 166 700) |
Baseline covariates used for spinal stenosis models were age, sex, comorbid stomach conditions, straight leg raise or femoral tension sign, smoking status, comorbid joint conditions, patient self-assessed health trend, annual income, compensation, body mass index, baseline EuroQol EQ-5D score, and center. Baseline covariates used for degenerative spondylolisthesis models were age, sex, work status, depression, osteoporosis, joint problems, current symptom duration, reflex deficit, number of moderate or severe stenotic levels, baseline EuroQol EQ-5D score, baseline stenosis bothersomeness, and center.
Percentage of bootstrapped samples in which estimated cost per QALY gained was less than $100 000.
Versus nonoperative management.
Circumferential fusions included anterior, posterior, and transforaminal lumbar interbody fusions.