The Utility of Noncontrast Computed Tomography in the Prompt Diagnosis of Postoperative Complications After Percutaneous Nephrolithotomy

Are hemostatic agents for selective cases of tubeless percutaneous nephrolithotomy necessary for access tract control? A randomized control trial

PURPOSE

To evaluate the efficacy of percutaneous nephrolithotomy (PCNL) access tract sealing agent. Fibrin glue and Tachosil^® were used for sealing the access tract and compared to the control. Post operative computed tomography (CT) scan was used to evaluate those efficacies.

METHODS

A total of 108 patients were randomized to three groups: In group 1, the access tract was sutured, and compressive dressing was done. In group 2, the fibrin glue was injected into the access tract with a tip applicator at the end of operation. And group 3, Tachosil^® was rolled on its longitudinal axis and plugged into the access tract. Non-contrast CT at POD 1 was taken and perirenal hematoma thickness was measured and graded. Hemoglobin, hematocrit, VAS score, stone-free status, and hospital stay were analyzed.

RESULTS

Preoperative demographic differences were not significant in all three arms. Postoperative CT scans in all groups demonstrated mostly minimal grade access tract hematomas. Mean perirenal hematoma thickness showed no significant differences (2.66 ± 3.74, 2.73 ± 3.85, 2.54 ± 4.37 mm, p = 0.981), respectively. Postoperative hemoglobin drop (0.75 ± 0.58, 0.84 ± 0.47, 0.91 ± 0.60 g/dl, p = 0.74), stone-free rate (93.75, 87.87, 87.87%, p = 0.121), VAS (p = 0.499) and hospital stay (1.81 ± 0.84, 1.48 ± 0.71, 1.59 ± 0.75 day, p = 0.127) were not significantly different between the groups.

CONCLUSION

Fibrin glue and Tachosil^® in tubeless PCNL were not necessary for postoperative access tract control.

Ptotic Right Retro-renal Liver Lobe Injury During Supine Percutaneous Nephrolithotomy Managed by Hemostatic Sponge

Percutaneous nephrolithotomy is an invasive procedure applied to large and complex stones in the prone or supine position. Various complications—but mostly fever or bleeding—can be seen during and after the procedure. Neighboring organ injuries are rare during access. Liver injuries are rarely seen and have a better clinical prognosis than other organ injuries. We present the management of liver injury with ptosis of the retro-renal right lobe as a complication during supine percutaneous nephrolithotomy.

Impact of Implementing Contrast-Enhanced Ultrasound for Antegrade Nephrostogram After Percutaneous Nephrolithotomy

OBJECTIVES

To report results from a quality improvement (QI) project evaluating diagnostic performance, hospital resource use, and patient response data for postoperative contrast-enhanced ultrasound (CEUS) antegrade nephrostogram after percutaneous nephrolithotomy.

METHODS

For this Health Insurance Portability and Accountability Act-compliant, Institutional Review Board-approved study, QI data were deidentified and analyzed. On the first postoperative day after percutaneous nephrolithotomy, patients underwent both CEUS and fluoroscopic antegrade nephrostogram. For CEUS, 1.0 mL of Lumason (sulfur hexafluoride lipid type A microspheres; Bracco Diagnostics, Inc, Monroe Township, NJ) was injected via an indwelling nephrostomy tube, with ureteral patency confirmed by identifying intravesical ultrasound (US) contrast. Diagnostic performance for ureteral patency and contrast extravasation was calculated (with fluoroscopy as the reference standard). The examination time, room time, physician time, hospital costs, and patient response data were compared. The mean, standard deviation, 95% confidence interval, differences in mean, and 95% confidence interval of differences were calculated.

RESULTS

Eighty-one examinations were performed in 73 patients during the QI period. The sensitivity and specificity of CEUS for ureteral patency were 96% and 57%, respectively. There was no significant difference in time metrics between modalities, and the cost analysis showed lower direct and indirect costs for CEUS. Patient responses revealed lower levels of comfort for CEUS relative to fluoroscopy, without significant differences in reported pain or effort levels.

CONCLUSIONS

Contrast-enhanced US showed very high sensitivity for ureteral patency; the relatively low specificity may have resulted from false-negative results in fluoroscopy. The hospital costs and resource use of CEUS compared favorably to fluoroscopy. Contrast-enhanced US also offers inherent advantages, including portability and lack of ionizing radiation.

Splenic Injury During Percutaneous Nephrolithotomy: A Case Report of a Rare Complication

Percutaneous nephrolithotomy has often been the preferred method for large and complex kidney stones. During percutaneous access to the collecting system, we encounter organ injuries due to anatomic neighborhoods. However, splenic injury is a relatively rare complication. We aimed to report how the complication process was managed conservatively in our case with transsplenic access. Then, a brief literature review on management strategy in similar conditions is highlighted. 

National Imaging Trends after Percutaneous Nephrolithotomy

PURPOSE

Followup imaging after percutaneous nephrolithotomy serves to detect postoperative complications, residual fragments and silent hydronephrosis. However, the timing and optimal imaging modality remain poorly defined. We describe imaging use patterns after percutaneous nephrolithotomy.

MATERIALS AND METHODS

In the MarketScan® database we identified patients 17 to 64 years old who underwent percutaneous nephrolithotomy between 2007 and 2014. Imaging modalities were identified by CPT, and ICD-9 and 10 codes, and tracked for 1 year after percutaneous nephrolithotomy. The modalities included computerized tomography, renal ultrasound, abdominal x-ray and intravenous pyelogram. Cumulative longitudinal use patterns were characterized and the association with demographic factors was assessed by the chi-square test.

RESULTS

Of the 6,495 patients included in analysis 29% and 15% had undergone no postoperative imaging by 3 and 12 months, respectively. While abdominal x-ray was the most common modality at 3, 6 and 12 months, performed in 46%, 53% and 62% patients, respectively, nearly 50% underwent computerized tomography by 1 year. Of these patients 34% underwent computerized tomography within 3 months, which was done within the first 3 days in 69%. During the study period renal ultrasound use increased by 13% while computerized tomography and abdominal x-ray use remained relatively stable. Female gender, residence in the Northeast, no health maintenance organization status and treatment in a metropolitan statistical area were independently associated with higher rates of renal ultrasound on multivariate analyses (p <0.05).

CONCLUSIONS

Among insured adults national imaging patterns vary following percutaneous nephrolithotomy. Many patients do not receive any followup imaging while approximately half undergo computerized tomography within a year. Imaging patterns may be evolving with the increased use of ultrasound.

Residual stones after percutaneous nephrolithotomy: comparison of intraoperative assessment and postoperative non-contrast computerized tomography

OBJECTIVES

To compare the intraoperative surgeon perspective for detection of residual fragments (RFs) after percutaneous nephrolithotomy (PNL) with postoperative NCCT.

METHODS

A prospective study of adult patients who underwent PNL between March and September 2014 was conducted. Stone complexity was evaluated using the Guy's stone score (GSS). All patients were evaluated by pre- and postoperative NCCT. After the procedure, the surgeon had been asked whether there were residual stones or not. The sensitivity, specificity and predictive values were tested against postoperative NCCT. Predictors of accurate intraoperative assessment were determined using univariate and multivariate statistical analyses.

RESULTS

The study included 306 consecutive patients. The surgeons reported no residual stones in 236 procedures; of whom 170 (72%) were reported stone-free by NCCT. On the other hand, 65 out of 70 procedures (93%) reported with residual stones by the surgeons were true by NCCT. The sensitivity was 50% and the NPV was 72%, while the specificity was 97% and the PPV was 93%. On multivariate analysis, only lower GSS (p < 0.001) was independently associated with true negative surgeon opinion.

CONCLUSIONS

Although there was a high surgeon ability to detect post-PNL residual stones, postoperative imaging is mandatory because of the high false negative rates and low NPV. The surgeon opinions can be judged only in stones with lower GSS. The NPV could be enhanced if a consistent definition of clinically significant RFs is introduced.

Nephrolithiasis Greater Than 2 cm and Splenomegaly

A 67-year-old male presented with left kidney stones in renal pelvis, 15 mm length. Preoperative CT showed massive splenomegaly. Retrograde intrarenal surgery approach was decided to avoid splenic injury, achieving the absence of residual stones.

Cross-sectional imaging of iatrogenic complications after extracorporeal and endourological treatment of urolithiasis

Extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) currently represent the mainstay treatment options for the vast majority of patients with urolithiasis, with limited contraindications and high success rates. However, minimally invasive extracorporeal and endourological treatments are associated with a non-negligible morbidity including occasional life-threatening occurrences. These complications represent a source of concern for urologists since they may result in prolonged hospitalisation, need for surgical, endoscopic or interventional treatment, long-term renal impairment, and sometimes even medical malpractice claims. Due to the increasing prevalence of urolithiasis and the large number of therapeutic procedures performed, in hospitals with active urologic practices radiologists are increasingly requested to investigate suspected post-procedural complications following ESWL, PCNL or ureteroscopic stone removal. Based upon our experience, this pictorial essay provides an overview of current extracorporeal and endourological treatment modalities for urolithiasis, including indications and possible complications according to the most recent guidelines from the European Association of Urology (EAU). Afterwards, we review the clinical features and cross-sectional imaging appearances of common and unusual complications with case examples, including steinstrasse, subcapsular, perirenal and suburothelial haemorrhages, severe urinary tract infections (such as pyeloureteritis, pyelonephritis, renal abscesses and pyonephrosis), ureteral injuries and delayed strictures.

Teaching points

• Extracorporeal lithotripsy, percutaneous nephrolitotomy and ureteroscopy allow treating urolithiasis.

• Minimally invasive extracorporeal and endourological treatment have non-negligible morbidity.

• Multidetector CT allows confident assessment of stone-free status and postprocedural complications.

• Main complications include steinstrasse, bleeding, severe infections, ureteral injuries and strictures.

• Imaging triage allows the choice among conservative, surgical, endoscopic or interventive treatment.

Is computed tomography mandatory for the detection of residual stone fragments after percutaneous nephrolithotomy?

The introduction of minimally invasive endourologic procedures for upper urinary stone disintegration has closed the curtain on the era of open surgery for upper urinary tract stones in which complete stone eradication was the rule. This shift to minimally invasive procedures has led to the introduction of new terminology, such as stone-free rates and residual stone fragments, the presence of which after treatment was considered an acceptable therapeutic end point. Percutaneous nephrolithotomy (PCNL) is currently considered the procedure of choice for large renal stones. Its use has been greatly facilitated by the favorable profile of multidetector CT with regard to its sensitivity in detecting small stones. Despite the fact that CT is considered essential for the diagnosis and exact localization of stones and has been used for the creation of percutaneous tracts in PCNL, however, its routine use for the post-PCNL detection of residual stones has not been established. There is evidence that routine application of post-PCNL CT provides additional advantages compared with other imaging modalities-namely, the identification of the presence and location of even small residual fragments, which has been shown to cause significant trouble and necessitate secondary procedures in a significant cohort of patients after PCNL. On the other hand, the issues of cost, availability of CT scanners, and radiation exposure along with the acceptable sensitivity, cost, and availability of other imaging studies has raised doubts as to whether CT should be the routine imaging study after PCNL. The present review will discuss the concept of clinically significant residual fragments and comment on the advantages and drawbacks of different imaging studies used for the detection of residual stones after PCNL. This review also aims to clarify the indications in which CT should routinely be performed or could be omitted in the follow-up after PCNL.