Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
J Urol. 2010 Jan;183(1):188-93. doi: 10.1016/j.juro.2009.08.135.
We performed a cost comparison of immediate second look flexible nephroscopy vs expectant management for post-percutaneous nephrostolithotomy residual fragments.
We used a decision analysis model to compare the cost of managing residual fragments by second look flexible nephroscopy vs observation. Outcomes of residual fragments after percutaneous nephrostolithotomy were determined from institutional experience and published shock wave lithotripsy series. Cost data were obtained from billing records. One-way sensitivity analysis was done to evaluate incurred costs of second look flexible nephroscopy while varying the likelihood of a stone event, the probability of surgery and the cost of surgical intervention. Two-way sensitivity analysis was done to assess the model across a range of scenarios.
Based on data in the literature and our institutional experience 40% of patients with residual fragments 4 mm or less had a stone event, of whom 57% required surgical intervention. Based on these estimates the average cost of expectant management for a residual fragment 4 mm or less vs greater than 4 was $1,743 vs $4,674. The average incremental cost of second look flexible nephroscopy at our institution was $2,475. Two-way sensitivity analysis showed that varying assumptions dramatically altered conclusions about the cost benefit of second look flexible nephroscopy.
Our model suggests that second look flexible nephroscopy is not cost advantageous in all patients with post-percutaneous nephrostolithotomy residual fragments. Cost benefit analysis is significantly impacted by the likelihood of a stone related event, the need for surgical intervention and surgical costs. Compared to an observational strategy second look flexible nephroscopy incurs lower costs for greater than 4 mm but not for 4 mm or less residual fragments.
我们对经皮肾镜碎石取石术后残留结石行即时二期软性肾镜检查与保守观察的成本进行了比较。
我们使用决策分析模型比较了二期软性肾镜检查与观察治疗残留结石的成本。经皮肾镜碎石取石术后残留结石的结果来自机构经验和已发表的体外冲击波碎石系列。成本数据来自计费记录。通过改变结石事件的可能性、手术的可能性和手术干预的成本，对软性肾镜检查的附加成本进行了单因素敏感性分析。进行了双向敏感性分析以评估模型在各种情况下的表现。
根据文献和我们机构的经验数据，40%的残留结石<4mm 的患者发生结石事件，其中 57%需要手术干预。根据这些估计，残留结石<4mm 与>4mm 的患者保守治疗的平均成本分别为 1743 美元和 4674 美元。我们机构软性肾镜检查的平均附加成本为 2475 美元。双向敏感性分析表明，假设的变化极大地改变了软性肾镜检查的成本效益的结论。
我们的模型表明，对于经皮肾镜碎石取石术后残留结石的所有患者，二期软性肾镜检查并不一定具有成本优势。成本效益分析受结石相关事件的可能性、手术干预的必要性和手术成本的显著影响。与观察策略相比，软性肾镜检查对于>4mm 的残留结石的成本较低，但对于 4mm 或更小的残留结石则不然。
