Point of View

Is lumbar spine fusion a cost-effective treatment for individuals with chronic low back pain? Fritzell et al address this important question using retrospectively ascertained health care costs and productivity losses among participants in the Lumbar Swedish Spine Study, which randomized individuals to receive one of three types of fusion or nonoperative care. Eligible participants had experienced low back pain for at least 2 years and were unable to work or were similarly disabled. Although retrospective cost ascertainment is fraught with difficulty because of potential recall biases, significantly higher costs are reported for instrumented fusion relative to noninstrumented fusion. For the 2-year follow-up period, average additional health care costs (SEK 57,800) and societal costs (SEK 67,700 inclusive of health care) are noted for individuals undergoing fusion relative to nonoperative treatment. To assess whether these costs represent a good use of resources, costs are weighed relative to the average gains in effectiveness for instrumented versus noninstrumented fusion and for all fusion types versus nonoperative care using four measures: (1) percent reporting improvement in their condition; (2) back pain visual analogue scale (VAS); (3) Oswestry disability index (ODI); and (4) return to work. Instrumented fusion was significantly more costly than noninstrumented fusion but did not lead to appreciable differences in any of the endpoints. Thus, there is good evidence that instrumented fusion is not cost-effective when compared with noninstrumented fusion. Although caution is warranted when generalizing economic study results beyond the country of origin because of countryspecific differences in costs of health care and productivity losses, it is unlikely that instrumented fusion would be costeffective in another setting because of the similar health and work outcomes across fusion groups. In contrast, for individuals with treatment resistant chronic low back pain, lumbar fusion lead to significantly better outcomes for all endpoints relative to nonoperative treatment. Despite use of multiple effectiveness measures, Fritzell et al do not provide results that allow the economic value of lumbar spine surgery to be compared with that reported for other common health care interventions (e.g., surgery for heart disease). To do so would require a general effectiveness endpoint, such as the quality-adjusted life year (QALY). QALYs, which account for morbidity by valuing each year of health on a scale that typically ranges from 0 (worst imaginable health) to 1 (perfect health), are recommended for assessing the value of health interventions. Several well-validated instruments that allow QALY estimation are now available including the EuroQol EQ-5D and the Health Utilities Index (HUI). In the absence of such endpoints, one may attempt to translate the 26% differential in reported improvement for those undergoing fusion to the QALY scale by making assumptions about the associated (but unmeasured) average annual QALY gain. However, as the magnitude of the assumed average annual QALY gain is varied from 0.1 to 0.3, the added cost per QALY gained for lumbar fusion ranges widely from SEK 1,300,000 (approximately US $157,000) to 430,000 (approximately US $52,000). This back-of-the-envelope calculation assumes a comparable QALY gain with improvement in either the fusion or nonoperative group. Nonetheless, it is evident that the magnitude of the QALY gain is a critically important determinant of costeffectiveness. Likewise, a similar phenomenon is easily demonstrated for the durability of the surgery effect. All of the analyses reported by Fritzell et al consider only a 2-year time horizon; yet, if cost differences remain stable and health gains are durable, the economic value of lumbar fusion will become more favorable. Without a QALY measure, another approach to assess the value of lumbar fusion is to consider society’s “willingness to pay” to attain the reported outcomes. For example, is it worth paying an additional SEK 57,800 to 67,700 (approximately US $7,000–8,000) for lumbar fusion given the 26% improvement (or 6-point ODI or 13-mm back pain VAS or 17.5% return-towork) differential between fusion and nonoperative care groups at 2-years? The fact that Fritzell et al’s analysis allows such questions to be more precisely posed brings us one step closer toward answering the question of whether lumbar spine surgery is a cost-effective use of resources. As constrained healthcare budgets continue to foster interest in cost-effective approaches to disease management, it is likely that further evidence will come from prospective economic evaluations conducted clinical trials. One such ongoing study, the Spine Patient Outcomes Research Trial (SPORT), will address the costeffectiveness of operative versus nonoperative treatments for three different underlying chronic low back pain etiologies (intervertebral disc herniation, spinal stenosis, and spondylolisthesis). Prospective economic evaluations, such as that planned for SPORT, should provide a firm evidence base for identifying cost-effective approaches to treatment of chronic low back pain.