Cost-Effectiveness of Corrective Fusion Surgeries for Adult Spinal Deformities

A Comparison by Operative Method

Hideyuki Arima, MD, PhD; Tomohiko Hasegawa, MD, PhD; Yu Yamato, MD, PhD; Masashi Kato, BS; Go Yoshida, MD, PhD; Tomohiro Banno, MD, PhD; Shin Oe, MD, PhD; Yuki Mihara, MD, PhD; Hiroki Ushirozako, MD, PhD; Tomohiro Yamada, MD; Yuh Watanabe, MD; Koichiro Ide, MD; Keiichi Nakai, MD; Kenta Kurosu, MD; Yukihiro Matsuyama, MD, PhD

Disclosures

Spine. 2021;46(18):1249-1257. 

In This Article

Results

Participant Characteristics

Of the 311 patients aged ≥50 years who underwent corrective fusion surgery for ASD during the study period, 220 met the inclusion criteria, of whom 173 (78.6% of eligible patients) could be followed up using radiographs and HRQOL questionnaires for 2 years postoperatively (Figure 1). The patient' demographic has been detailed in Table 1. The LLIF group had significantly more degenerative kyphoscoliosis, and the three-column group had significantly more degenerative kyphosis, kyphosis after vertebral fracture, and iatrogenic kyphosis.

Figure 1.

A chart capturing participant flow through the study eligibility criteria.

Surgical Details and Outcomes

Surgical details are described in Table 2. Revision surgeries were performed 32 times in 29 ASD patients (17%). There were 16 cases of rod fracture, four of proximal junctional failure (PJF), three of distal junctional failure (DJF), three of implant-related disorders, four of hematomas, one of malalignment, and one of infection. There were no significant differences between the three groups concerning the number of fused vertebrae, UIV level, length of hospital stays, or overall perioperative complication rate. LLIF group had significantly higher rate of staged surgeries, greater surgery time, and lesser intraoperative blood loss than the other two groups. The revision surgery rate was significantly higher in the three-column group.

Radiographic Parameters

The mean postoperative LL, PT, PI minus LL, SVA, coronal Cobb significantly improved from 10.7° to 42.4°, 35.7° to 25.5°, 40.9° to 11.0°, 116.3 mm to 57.2 mm, and 29.1° to 9.3°, respectively (all P < 0.001) (Table 3). Preoperative PI-LL and SVA were significantly worse in the three-column group. Even 2 years postoperatively, PI-LL and SVA were worse in the three-column group than in the LLIF group.

Patient-reported Outcome Measures Parameters

Values of all SRS-22r domains significantly improved 2 years postoperatively (all P < 0.001) (Table 4). Preoperatively, SRS-22r pain was worse in the Grade-2 group than in the other two groups, but there was no significant difference in other parameters among the three groups. Postoperatively, SRS-22r pain was significantly worse in the Grade-2 group than in the LLIF group, but there was no significant difference in other parameters among the three groups. The cumulative improvement in QALY over the 2 years was 0.16 on average, 0.13 for the Grade-2 group, 0.15 for the three-column group, and 0.18 for the LLIF group, with no significant differences among the three groups. Post-hoc power analysis calculated power (1-βerror probability) as 0.83 when the effect size was 0.25, and the α-error probability was 0.05, showing that the study had sufficient power.

Medical Expense and Cost-effectiveness for ASD Surgery

The average medical expense for the initial surgery was USD 72,240, and the average total medical expense over the 2 years after the initial surgery was USD 76,294 (Table 5). Medical expenses for the initial surgery were significantly higher in the LLIF group. The average surgical cost was USD 58,541 (81% of the total cost), and the average medical expenses for revision surgeries were USD 21,917 per hospitalization. Regarding the total medical expenses over the 2 years after the initial surgery, the three-column and LLIF groups had higher costs than the Grade-2 group. The cost/QALY 2 years after surgery was USD 492,276 on average (USD 509,370 for the Grade-2 group, USD 518,406 for the three-column group, and USD 463,798 for the LLIF group).

Comparison of Complications, Revision Surgery Rate, and Cost-effectiveness According to the Different LIV

The group with only S1 screw as LIV (S1 group) and the group with S1 screw and iliac screw as LIV (Iliac group) were compared (Supplementary Table 1, http://links.lww.com/BRS/B740). Three patients (27%) in the S1 group and 26 patients (16%) in the iliac group required revision surgery; however, there was no statistically significant difference (P = 0.335). The cost/QALY of surgery after 2 years was USD 1,141,234 for the S1 group and USD 476,876 for the iliac group.

Comparison of Complications, Revision Surgery Rate, and Cost-effectiveness of Different Surgical Procedures for Degenerative Kyphoscoliosis

There were no significant differences in the overall perioperative complication rate among the three groups (Supplementary Table 2, http://links.lww.com/BRS/B740). The revision surgery rate was significantly higher in the three-column group (40%). The three-column and LLIF groups had higher total medical expenses over the 2 years after the initial surgery than the Grade-2 group. The cost/QALY of surgery after 2 years was USD 524,899 for the Grade-2 group, USD 611,253 for the three-column group, and USD 442,888 for the LLIF group.

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