A comparative study of air pyelogram and contrast pyelogram for initial puncture access and to see its efficacy during percutaneous nephrolithotomy.

Objective: The current investigation was aimed to compare the safety, efficacy, adverse effects, and outcome of air pyelogram versus contrast pyelogram for percutaneous nephrolithotomy.

Materials and methods: This was a cross-sectional study conducted from August 2018 to November 2020, which included 400 patients with a clinical diagnosis of renal calculus and randomly (1:1) assigned into Group I (air pyelogram) and Group II (contrast pyelogram). Air was injected in Group I and diatrizoate meglumine 76% was used in Group II for PCS identification. In the case of difficulty in visualization in either group, a mixture of contrast and air was used. The following parameters were assessed: duration of access, total duration of radiation exposure during access, total attempts needed to puncture the desired calyx, failure rate, complications, and outcomes.

Results: Both the groups were comparable including renal calculus characteristics. The mean (standard deviation) duration of access was 3.08 (1.21) and 5.23 (1.02) min (P < 0.0001) in Groups I and II, respectively; in 85% and 57.5% of patients (P < 0.0001), respectively, the caliceal puncture was done in a single attempt. The duration of radiation exposure was more in Group II (P < 0.0001). The failure rate (22%) was higher and statistically significant in Group II. The stone clearance rate was not statistically significant between the groups (P = 0.380). No patient had hypoxia, cardiopulmonary complications, and air embolism in perioperative period.

Conclusion: Air contrast is effective and safe, and it reduces the duration of caliceal puncture and radiation exposure with lower failure rate. If both air and contrast fail, a combination of both may be effective.