Indirect evidence for the volume-outcome relationship for corrective surgery for anorectal malformations using the...

Anorectal malformations (ARM) are rare congenital anomalies requiring complex surgical correction. Due to low caseload and heterogeneous cohorts, prior studies failed to establish whether higher hospital caseloads improve outcomes. This study applies the IQWiG V24-07 framework to evaluate whether indirect evidence from other surgical procedures can inform a potential volume-outcome relationship in ARM surgery.

An interdisciplinary expert panel conducted a formal consensus using three steps: (1) identifying suitable source populations; (2) systematically comparing these with the ARM population using 12 IQWiG criteria; and (3) evaluating transferability through structured discussion and voting.

Adult rectal resection was unanimously selected as evidence source population due to robust evidence of a volume-outcome relationship and relevant surgical commonalities, including deep pelvic dissection. Of the 12 transferability criteria, consensus was reached in six. Differences in comorbidities, concomitant treatment, and setting were judged irrelevant for transferability. Differences in sociodemographic and disease-specific characteristics were considered estimable in their impact. Divergent ratings were observed for diagnosis, intervention, endpoints, specialization, and follow-up care. Short-term technical outcomes such as anastomotic leakage were deemed transferable, whereas mortality was considered non-informative in ARM. Functional outcomes required subtype-specific interpretation.

This structured analysis supports the existence of a volume-outcome relationship for ARM surgery.