Zeph Okeke

Evaluation and Comparison of Urolithiasis Scoring Systems Used in Percutaneous Kidney Stone Surgery

PURPOSE Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes. METHODS We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system. RESULTS We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay. CONCLUSIONS All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting.

Perioperative outcomes of off‐clamp vs complete hilar control laparoscopic partial nephrectomy

Whats known on the subject? and What does the study add?

Digital Ureteroscopy: The Next Step

BACKGROUND Flexible ureteroscopy is used for diagnosing and treating upper urinary tract diseases. Despite technological advances in making flexible ureteroscopes smaller, they suffer from a grainy image. Therefore, new technology with better resolution is needed. NEW TECHNOLOGY The new Invisio DUR-D digital flexible ureteroscope from Gyrus ACMI was tested. The tip houses dual LED-driven light carriers, which obviates the need for an external light source, thus eliminating the risk of drape fires and patient burns. A 1-mm digital camera at the tip eliminates the need for fragile low-resolution fiberoptics and provides superior resolution. Since there are no external cameras or light cables, the DUR-D is much lighter (505 g compared with 1012 g). Laser detection system deactivates the laser to prevent accidental misfiring of the laser within the ureteroscope. CONCLUSIONS The latest generation of digital ureteroscopes provides superior resolution and safety. Long term use is needed to test its durability.

Anatomical Variation Between the Prone, Supine, and Supine Oblique Positions on Computed Tomography: Implications for Percutaneous Nephrolithotomy Access

OBJECTIVE To determine anatomical variations between the prone, supine, and supine oblique positions that are likely to affect percutaneous renal access. MATERIAL AND METHODS Twenty patients underwent computed tomography urograms in the supine and prone positions. Twenty patients underwent supine oblique and prone scans. Mean nephrostomy tract length, maximum access angle, and anterior-posterior renal position were calculated. RESULTS Mean nephrostomy tract length was shorter in the prone position (82.6 mm right kidney, 85.4 mm left kidney) compared with the supine position (108.3 mm right kidney, P<.001; 103.7 mm left kidney, P<.001). Prone tract length was also shorter than supine oblique tract length (86.1 mm vs 96.5 mm; P=.048). Mean maximum access angle was significantly greater (P=.018 right kidney; P=.007 left kidney) in the prone position (right kidney 99.7°, left kidney 104.0°) compared with the supine position (right kidney 87.7°, left kidney 89.4°). The same was true for the prone compared with the supine oblique position (75.8° vs 58.7°; P=.004). No difference was noted in anterior-posterior renal position between the supine and prone positions (20.3 mm vs 26.7 mm; P=.094) or supine oblique and prone positions (22.8 mm vs 15.6 mm; P=.45). CONCLUSIONS The prone position is associated with a significantly shorter nephrostomy tract length and more potential access sites, which may improve ease and safety of percutaneous renal access.

The debate over percutaneous nephrolithotomy positioning: a comprehensive review.

PURPOSE We summarized the arguments for and against prone and supine percutaneous nephrolithotomy, and determined whether any clinical characteristics warrant 1 position over the other. MATERIALS AND METHODS We searched PubMed® for articles on prone anesthesia, abdominal organ movement between the prone and supine positions, and percutaneous nephrolithotomy case series since 1998. RESULTS The prone position is associated with a decrease in the cardiac index and an increase in pulmonary functional residual capacity. An increased risk of liver and spleen injury exists for upper pole puncture with the patient supine. Potential injury to the colon is greatest during prone lower pole access. A greater surface area for percutaneous access exists with the patient prone. The supine position decreases surgeon radiation exposure and promotes spontaneous stone drainage during the procedure. Two comparative series show that the supine position is associated with significantly shorter operative time. In contrast, noncomparative case series suggest decreased operative time and blood loss when treating staghorn calculi with the patient prone. CONCLUSIONS Each position is feasible but more randomized studies are needed to accurately determine the relative efficacy and morbidity of the 2 positions.

Management of urolithiasis in patients after urinary diversions

What’s known on the subject? and What does the study add?

Prospective comparison of outcomes of percutaneous nephrolithotomy in elderly patients versus younger patients.

PURPOSE The purpose of the study was to prospectively compare operative and postoperative characteristics and outcomes in elderly patients undergoing percutaneous nephrolithotomy (PCNL) compared with younger patients. PATIENTS AND METHODS Prospectively collected data from the Clinical Research Office of the Endourological Society (CROES) Global PCNL Study database were used. Elderly patients were defined as those aged 70 years and above, while younger patients were those between 18 and 70 years of age. Matched and unmatched group comparisons were performed based on imaging modality used for assessing stone-free status. Patient characteristics, operative data, and postoperative outcomes were compared. RESULTS The median age of the elderly group vs the young group was 74 years (range 70-93 years) vs 49 years. In the unmatched analysis, staghorn stones were seen at higher rates in the elderly group (27.8% vs 21.8%, P=0.014); however, the mean stone size was not significantly different (465.0 vs 422.8, P=0.063). The length of hospitalization was significantly longer in the elderly group compared with the young group in the unmatched analysis (5 days vs 4.1 days, P<0.001). The same difference was not apparent in the matched analysis (5.0 days vs 4.4 days, P=0.288). Overall complication rates were not significantly different in the unmatched analysis. In the matched analysis, however, a statistically significant higher rate of overall complications was seen. Stone-free rates were similar among all groups. CONCLUSION PCNL in elderly patients over the age of 70 years produces results comparable to those seen in younger patients. With only a slightly higher-be it statistically significant-complication rate, the stone-free rate in older patients was the same as in the younger group.

Renal Drainage After Percutaneous Nephrolithotomy

Exit strategy after percutaneous nephrolithotomy (PCNL) is an area of continuing innovation to improve postoperative morbidity and operative outcomes for patients. The two important components of an exit strategy after PCNL are hemostasis and renal drainage. We review the different techniques of renal drainage after PCNL-ie, nephrostomy tube, ureteral stents, and totally tubeless strategy with critical discussion of available evidence for and against each of these techniques. We conclude that the optimal renal drainage method depends on patient characteristics and the operative course; hence, it should be individualized. To simplify this, we group patients undergoing PCNL as routine, problematic, and complicated, based on increasing complexity of the procedure and procedural complications. In routine PCNLs, we favor placement of an ureteral stent or a small-bore nephrostomy tube. In problematic and complicated PCNLs, we think the evidence directs toward placement of a nephrostomy tube, small bore being an option in problematic PCNLs.

Stenting for malignant ureteral obstruction: Tandem, metal or metal‐mesh stents

Extrinsic malignant compression of the ureter is not uncommon, often refractory to decompression with conventional polymeric ureteral stents, and frequently associated with limited survival. Alternative options for decompression include tandem ureteral stents, metallic stents and metal‐mesh stents, though the preferred method remains controversial. We reviewed and updated our outcomes with tandem ureteral stents for malignant ureteral obstruction, and carried out a PubMed search using the terms “malignant ureteral obstruction,” “tandem ureteral stents,” “ipsilateral ureteral stents,” “metal ureteral stent,” “resonance stent,” “silhouette stent” and “metal mesh stent.” A comprehensive review of the literature and summary of outcomes is provided. The majority of studies encountered were retrospective with small sample sizes. The evidence is most robust for metal stents, whereas only limited data exists for tandem or metal‐mesh stents. Metal and metal‐mesh stents are considerably more expensive than tandem stenting, but the potential for less frequent stent exchanges makes them possibly cost‐effective over time. Urinary tract infections have been associated with all stent types. A wide range of failure rates has been published for all types of stents, limiting direct comparison. Metal and metal‐mesh stents show a high incidence of stent colic, migration and encrustation, whereas tandem stents appear to produce symptoms equivalent to single stents. Comparison is difficult given the limited evidence and heterogeneity of patients with malignant ureteral obstruction. It is clear that prospective, randomized studies are necessary to effectively scrutinize conventional, tandem, metallic ureteral and metal‐mesh stents for their use in malignant ureteral obstruction.

Habib Laparoscopic Bipolar Radiofrequency Device: A Novel Way of Creating an Avascular Resection Margin in Laparoscopic Partial Nephrectomy

INTRODUCTION Hemostasis during the laparoscopic partial nephrectomy (LPN) is a challenge. Usually, the renal hilum is clamped to minimize blood loss. However, prolonged ischemia leads to irreversible damage. Therefore, new technology is needed to minimize blood loss while performing LPN without hilar clamping. The Habib 4x Laparoscopic device (Angio Dynamics, Queensbury, NY) is a four-pronged bipolar radiofrequency probe that is proven to reduce blood loss in laparoscopic liver resections without hilar clamping. The aim of this pilot study was to evaluate this new technology in LPN. METHODS Three patients, with exophytic renal lesions (1.1-4 cm), underwent LPN without hilar clamping, using the Habib Laparoscopic device to create an avascular resection margin. RESULTS Mean operative time was 150.3 minutes, mean estimated blood loss was 100 cc, and none of the patients required transfusions. There was no significant difference between the mean pre- and postoperative serum creatinine levels (P > 0.05). All 3 resected masses were renal-cell carcinomas. Intraoperative frozen sections demonstrated negative margins in all cases. However, in the second case, with a renal lesion of 4 cm, the permanent section analysis on margins was read as focally positive. There were no complications. On follow-up imaging of up to 12 months, there were no recurrences. CONCLUSIONS The Habib 4x Laparoscopic device permits the resection of exophytic renal lesions without the need for hilar clamping. However, a cautery artifact can cause difficulty in interpreting the frozen-section analysis of resection margins. Therefore, its use should be restricted to lesions of less than 2 cm.