Determinants of resource utilization in the treatment of brain arteriovenous malformations

Abstract

Background and purpose: Preoperative embolization of arteriovenous malformations (AVMs) is thought to improve outcome following surgical resection of these lesions. The purpose of this study was to examine the cost associated with preoperative embolization and different surgical risk categories in the surgical treatment of brain AVMs.

Methods: In a review of 126 patients treated surgically for resection of AVMs, we noted the total days spent in the hospital and calculated the associated costs (from hospital and estimated professional fees). Surgical risk category was determined using the Spetzler-Martin grading system. We examined the effect of risk category, preoperative embolization, and outcome (Rankin score) on cost and inpatient days.

Results: Preoperative embolization and greater surgical risk were independently associated with higher total costs. Average adjusted cost for embolization and surgery was $78,400 +/- $4,900 versus $49,300 +/- $5,800 for surgery alone. Patients ranged in preoperative risk category from Spetzler-Martin grades II through V, with an average increase of $20,100 in total cost per Spetzler-Martin grade (95% CI, $13,500 to $28,100). Higher surgical risk category was also associated with more days spent in hospital, with an average increase of 6 days per increment in Spetzler-Martin grade (95% CI, 4 to 8). After surgical resection of an AVM, new neurologic deficits were associated with large differences in cost: $68,500 +/- $6,100 and 15 +/- 2 days in hospital for patients who were neurologically worse after surgery, versus $44,700 +/- $3,900 and 10 +/- 1 days for patients who were unchanged.

Conclusion: Preoperative embolization in the treatment of AVMs is associated with higher cost but not more days in the hospital. Patients with higher Spetzler-Martin grade AVMs utilize more hospital resources, in part because they have poorer neurologic outcome, and postoperative deficits are associated with higher costs and more days in the hospital.

fig 1.

A, Surgical risk versus cost (adjusted for cost of embolization). Spetzler-Martin grades V and IV differed from all other grades (P < .005 and P < .05, respectively). B, Surgical risk versus days in the hospital (adjusted for effect of embolization). Spetzler-Martin grades V and IV differed from grades III and II (P < .005 and P < .05, respectively). All values shown as mean ± SEM.

fig 2.

A, Postoperative neurologic status versus cost (adjusted for preoperative embolization). Difference in cost was significant (P = .016). B, Postoperative neurologic status versus days in hospital (adjusted for preoperative embolization). Difference in length of stay was significant (P = .008). All values shown as mean ± SEM.