Kidney stones can lead to significant morbidity and are known to impair health-related quality of life (HRQOL), similar to other chronic diseases such as diabetes and chronic renal failure.^1,2 As health care has shifted to more patient-centric care, patient-reported outcomes such as HRQOL are increasingly important measurements. Awareness of the impact of treatment decisions and surgical outcomes on patients with kidney stones can help improve patient counseling and assist with setting appropriate expectations.³

Traditionally, surgical outcomes after kidney stone surgery have been focused on “stone-free” status as a way to define success. However, absolute stone-free status is difficult to achieve despite our best efforts, especially when using computerized tomogram (CT) scans for postoperative imaging.⁴ Furthermore, definitions of “stone-free” vary in the literature with differing opinions about the residual fragment size that should be deemed as “clinically insignificant.” With no clear consensus among urologists, determining when to treat asymptomatic residual fragments can be challenging.

In this study, we used the Wisconsin Stone Quality of Life (WISQOL) questionnaire to compare the HRQOL of patients with residual fragments to patients who were rendered stone-free after surgical intervention for kidney stones. This is a subanalysis of cross-sectional data from centers within the North American Stone Quality of Life Consortium (Penn State HMC, University of Wisconsin-Madison, Dartmouth College and University of British Columbia). The WISQOL, a 28-item questionnaire, was self-administered to each participant. We retrospectively collected surgical data, including presence of residual fragments on postoperative imaging; the stone-free group was defined as no residual fragments (0 mm). We calculated total WISQOL score (28–140) and standardized domain scores (0–100), including social functioning (D1), emotional functioning (D2), stone-related impact (D3) and vitality (D4). Scores were compared between patients with residual fragments to those who were stone-free after surgical intervention.

There was a total of 313 patients (55.4% female) with an average±SD age of 54.5±13.45 years. Of the patients 60.4% were classified as absolutely stone-free, and 39.6% had residual stone fragments on postoperative imaging. We determined that residual fragments after surgical intervention (124 patients, mean±SD 110.5±27.8) are not associated with worse HRQOL as compared to stone-free cases after surgery (189 patients, mean±SD 115.4±23.6; p=0.12). Interestingly, unlike patients with residual stones and no secondary procedures, patients who underwent secondary stone surgery (28) had significantly lower total WISQOL scores (mean±SD 88.4±30.1 vs 116.6±25.0, p <0.0001), as well as lower domain scores (D1: 63.5 vs 84.8, p=0.001; D2: 45.7 vs 78.9, p <0.0001; D3: 52.0 vs 75.5, p <0.0001; D4: 43.1 vs 71.2, p <0.0001). In the majority of cases (94.7%), the secondary procedure was unplanned. Information for why secondary procedures were performed was limited due to the retrospective nature of this study. However, among those for whom details were available, 73.3% of secondary procedures were in asymptomatic patients. From these results, we concluded that repeat surgery solely to render the patient stone-free on imaging may actually be detrimental to patients’ HRQOL. Surveillance of nonobstructing residual stone fragments may thus be an acceptable management strategy in certain cases when the patient is not rendered stone-free after the initial surgery.

Since residual fragments can cause significant morbidity or be a nidus for future stone growth, stone-free status following surgical intervention should always remain the ultimate goal. However, when stone-free status is not achieved, we know residual fragments can remain asymptomatic and stable with appropriate preventive strategies. This symptom heterogeneity underscores the need for inclusion of patient-reported outcomes, such as HRQOL, to help clinicians counsel patients and better guide treatment decisions. Shared decision making is ultimately the key to making appropriate treatment decisions and emphasizes an individualized approach to kidney stone management.

We advocate a paradigm shift in the definition of successful surgical intervention from “stone-free” status alone to a definition that includes optimization of patients’ HRQOL. We acknowledge the limitations of our retrospective cross-sectional study, and future well designed prospective studies with less variability will be necessary to confirm our conclusions. However, our study adds to the growing literature that patient-reported outcomes such as HRQOL should also be taken into consideration.