New Techniques in Endourology

Computed Tomography-Guided Transgluteal PercutaneousNephrolithotripsy in an Ectopic Pelvic Kidney:

Novel Technique

Mohammad Alomar, MD, FRCS(C), and Husain Alenezi, MD

Abstract

Background and Purpose: Management of stones in the ectopic pelvic kidney can be very challenging. Treatmentof each patient should be individualized. We describe a new approach that is CT-guided transgluteal percu-taneous nephrolithotripsy (PCNL).Case and Technique: A 19-year-old male presented with symptomatic right ectopic pelvic kidney stones. He wastreated with CT-guided transgluteal PCNL. The patient was stone free at postoperative day 1. No major com-plications were observed, and the patient was discharged home on postoperative day 2.Conclusion: CT-guided transgluteal PCNL is a safe and effective option for selected patients with ectopic pelvickidney stones.

Introduction

Treatment of large and complex renal stones has beendramatically revolutionized after the advent of percu-

taneous nephrolithotripsy (PCNL). Patients with renal ano-malies and associated stones, however, still pose a greatchallenge to the managing urologist. Ectopic pelvic kidneywith stones necessitates careful individualized planning forthe treatent in each patient. Moreover, previous interventions,such as open surgery, can further complicate the situationbecause of possible fibrosis and risk of ischemia or vascularinjury.

Patients with ectopic pelvic kidneys and small burdenstones can be reasonably treated by shockwave lithotripsy(SWL) or ureteroscopy,1–4 while for patients with a stoneburden of more than 2 cm, PCNL is still the preferred option.PCNL has been mostly performed with a laparoscopy-assisted approach to mobilize the overlying intestinal seg-ments and establish access under direct vision.5–8

We describe a novel approach for the management of renalstones in the ectopic pelvic kidney.

Case and Technique

A 19-year-old male presented with lower abdominal painand gross hematuria. He had undergone open pyeloplasty atthe age of 15 years for ureteropelvic junction obstruction in aright ectopic pelvic kidney. Urinalysis revealed microscopichematuria and sterile pyuria. His serum creatinine level was82 lmol/L. CT demonstrated three stones in the lower calices

of the right pelvic kidney with total stone burden of 2 cm(Figs. 1–3). Renal radioisotope scans evidenced 42% splitfunction of the right kidney with excellent evacuation afterstanding up. Retrograde intrarenal access using an activelyflexible ureteroscope was successful. Stones were not reach-able after insertion of the smallest laser fiber or basket, how-ever, because of lost degree of angulation.

Options were discussed with the patient. He was offeredlaparoscopy-assisted PCNL or CT-guided transgluteal PCNLbecause the kidney was almost completely lying behind thebony pelvis. CT-guided PCNL was elected. Access was es-tablished by an interventional radiologist (Fig. 4) 1 day beforethe procedure. It was performed under CT guidance while thepatient was in a prone position.

To avoid injuring the sciatic nerve as well as the sacralplexus and the superior and inferior gluteal vessels, thepuncturing needle must be inserted as close to the sacrum aspossible, at the level of the sacrospinous ligament. With thisapproach, the sciatic nerve will be lying more laterally, whilethe sacral plexus and the gluteal vessels will be lying morecephalic. Thus, all major structures can be easily avoided. Theposition of the access was confirmed with antegrade injectionof contrast, which filled the pelvicaliceal system of the rightectopic kidney. No immediate complications were noted.

During the procedure, the usual insertion of a 5F end-holeureteral catheter was performed retrogradely, and then thetract was dilated using single-step dilation with 30F Ultraxx�balloon (Cook Medical) over an extra-stiff guidewire. Thedistance from skin to the punctured calix was 11.4 cm asmeasured by CT scan with the patient in the prone position.

Urology Division, College of Medicine and King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia.

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Therefore, a standard length 30F Amplatz sheath was in-serted, and the procedure was completed in the usual manner(Figs. 5 and 6). Stones were visualized using a flexiblenephroscope only and retrieved intact using a 3.4F basket.A 22 Fr Councill-tip nephrostomy tube was inserted at theend of the procedure (Fig. 7). The patient had an unevent-ful recovery.

The CT scan on postoperative day 1 showed a stone-freekidney. The nephrostomy tube was removed on postopera-tive day 2, after which excessive leakage of urine from theaccess site developed. This was managed successfully by in-sertion of an urethral catheter. The patient was dischargedhome on postoperative day 2 with an indwelling urethralcatheter. The patient was seen on postoperative day 4 in theclinic; he had been dry for more than 24 hours, so the urethralcatheter was removed.

Discussion

Treatment of patients with pelvic kidney stones representsa great challenge to urologists. Various treatment optionshave been reported in the literature, ranging from SWL tolaparoscopic nephrolithotomy.

Talic1 reported on 14 patients with pelvic kidney stoneswho were treated by SWL.1 Eighty-two percent of patientswho presented for follow-up visits (9 of 11) were stone free at3 months. Other reports, however, showed less encouragingresults, with stone-free rates from 54% to 57%.2,3 In our case,the stones were radiolucent, and the stone burden was large,thus precluding SWL as an option for treatment.

Retrograde intrarenal access is an alternative option, giventhe fast advancement of technology. Weizer and associates4

had a stone-free rate of 75% after ureteroscopy in four patientswith pelvic kidney stones. The mean stone burden was 1.4 cm.Although we managed to gain access to the stone-containingcalices, the degree of angulation was lost after introducing thesmallest instruments, precluding successful completion of theprocedure.

FIG. 2. Another axial CT scan showing two more stones inthe same kidney measuring 6 and 4 mm with major branchesof the internal iliac artery surrounding the kidney andadjacent rectum.

FIG. 3. Sagittal reconstructed CT slide showing the kidneylying mostly in the bony pelvis with the adjacent surroundingviscera.

FIG. 1. Axial CT scan slide showing 1-mm stone in the rightectopic pelvic kidney with surrounding vascular structures.

FIG. 4. Axial CT scan showing the transgluteal access per-formed by the interventional radiologist under CT guidance.

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The abnormal anatomic relationship between ectopic pel-vic kidneys and surrounding viscera makes blind percuta-neous access very risky, with high chance of injury, especiallyto overlying intestinal loops. Thus, most reported cases werelaparoscopy-assisted PCNL.5–8Laparoscopy was used tomobilize the bowel and establish transperitoneal renal accessunder direct vision in a retrograde or, more commonly,antegrade approach.

Laparoscopic pyelolithotomy is another option of treat-ment in patients with ectopic pelvic kidney stones. Chang andDretler9 and Harmon and colleagues10 reported two caseswith successful stone removal. Laparoscopic pyelolithotomy,however, is more appropriate for renal pelvic stones, while inpatients with multiple caliceal stones, there is still a potentialrisk of residual stones.

We believe the laparoscopic approach might jeopardizethe vascular supply to successful previous pyeloplasty. We

discussed this option with our patient, explaining that risk,and it was agreed not to proceed with laparoscopy.

Direct posterior renal access under fluoroscopic guidancemight be possible in certain patients. Watterson and co-workers11 were the first to report PCNL through the greatersciatic foramen. In their patient, contrast-enhanced CT scanrevealed no interposed bowel or vascular structures, andtransgluteal access to the kidney was possible under directfluoroscopic guidance.

In our patient, the scenario was different. The kidney wasin close proximity to the rectum and vascular structures, asseen on contrast-enhanced CT scan. Thus, posterior accessunder fluoroscopic guidance was potentially risky becauseof the high chance of visceral or vascular injury. We ado-pted the CT-guided transgluteal approach as a novelalternative for treatment of our patient. The access was es-tablished by a skilled interventional radiologist through thegreater sciatic foramen, which is a well-established, safeapproach used by interventional radiologists to drain deeppelvic abscesses and collections.12,13 It was first describedin 1986. The main complications of this approach are painin 20% of cases and bleeding, which is an uncommoncomplication.

Conclusion

Treatment options for patients with ectopic pelvic kidneystones remain individualized and range from relatively sim-ple procedures such as SWL to more complicated approaches,including PCNL and laparoscopy.

CT-guided transgluteal PCNL represents a valid safeoption in our patient. It gives the advantages of minimallyinvasive surgery with short convalescence and reducedpostoperative pain, while minimizing the possibility of in-juring the surrounding viscera and major vascular structuresin comparison with direct fluoroscopy-guided access.

We believe that CT-guided transgluteal PCNL can beadded to the armamentarium of management options inselected patients with ectopic pelvic kidney and stones.

FIG. 5. Single step balloon dilation of the tract.

FIG. 6. The kidney after balloon dilation and insertion ofa 30F sheath and two guidewires with the introduction of aflexible nephroscope into the pelvicaliceal system ante-gradely through the transgluteal access.

FIG. 7. Postoperative picture showing the 22F Councill-tipnephrostomy tube inserted though the transgluteal access.

400 ALOMAR AND ALENEZI

Disclosure Statement

No competing financial interests exist.

References

1. Talic RF. Extracorporeal shock-wave lithotripsy mono-therapy in renal pelvic ectopia. Urology 1996;48:857– 861.

2. Tunc L, Tokgoz H, Tan MO, et al. Stones in anomalouskidneys: Results of treatment by shock wave lithotripsy in150 patients. Int J Urol 2004;11:831–836.

3. Kupeli B, Isen K, Biri H, et al. Extracorporeal shockwavelithotripsy in anomalous kidneys. J Endourol 1999;13:349–352.

4. Weizer AZ, Springhart WP, Ekeruo WO, et al. Ureterocopicmanagement of renal calculi in anomalous kidneys. Urology2005;65:265–269.

5. Eshghi AM, Roth JS, Smith AD. Percutaneous transper-itoneal approach to a pelvic kidney for endourological re-moval of staghorn calculus. J Urol 1985;134:525–527.

6. Toth C, Holman E, Pasztor I, et al. Laparoscopicallycontrolled and assisted percutaneous transperitoneal ne-phrolithotomy in a pelvic dystopic kidney. J Endourol 1993;7:303–305.

7. Matlaga BR, Kim SC, Watkins SL, et al. Percutaneousnephrolithotomy for ectopic kidneys: Over, around, orthrough. Urology 2006;67:513–517.

8. Gupta NP, Mishra S, Seth A, Anand A. Percutaneous ne-phrolithotomy in abnormal kidneys: Single-center experi-ence. Urology 2009;73:710–715.

9. Chang TD, Dretler SP. Laparoscopic pyelolithotomy in anectopic kidney. J Urol 1996;156:1753.

10. Harmon WJ, Kleer E, Segura JW. Laparoscopic pyelo-lithotomy for calculus removal in a pelvic kidney. J Urol1996;155:2019–2020.

11. Watterson JD, Cook A, Sahajpal R, et al. Percutaneous ne-phrolithotomy of a pelvic kidney: A posterior approachthrough the greater sciatic foramen. J Urol 2001;166:209–210.

12. Harisinghani MG, Gervais DA, Hahn PF, et al. CT-guidedtransgluteal drainage of deep pelvic abscesses: Indications,technique, procedure-related complications, and clinicaloutcome. Radiographics 2002;22:1353–1367.

13. Butch RJ, Mueller PR, Ferrucci J Jr, et al. Drainage of pelvicabscesses through the greater sciatic foramen. Radiology1986;158:487–491.

Address correspondence to:Mohammad Alomar, MD, FRCS(C)

Department of SurgeryKing Khalid University Hospital

P.O. Box 2925Riyadh 11461Saudi Arabia

E-mail: alomarmo@gmail.com

Abbreviations UsedCT¼ computed tomography

PCNL¼percutaneous nephrolithotripsySWL¼ shockwave lithotripsy

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