使用軟式輸尿管鏡及可彎式輸尿管鞘於馬蹄腎腎盂輸尿管間結石達成無剩餘結石的案例報告及文獻回顧

廖凡霆、馮思中、李宗霖、黃亮鋼、甘弘成、邵翊紘、林柏宏、虞凱傑、吳俊德、莊正鏗

林口長庚紀念醫院外科部泌尿科

Complete Stone Free for Case of Horseshoe Kidney Ureteropelvic Junctional Stone Utilizing Flexible Ureterorenoscopy and Flexible Ureteral Access Sheath: A First Case & Review

Fan-Ting Liao, See-Tong Pang, Chung-Lin Lee, Liang-Kang Huang, Hung-Cheng Kan, I-Hung Shao, Po-Hung Lin, Kai-Jie Yu, Chun-Te Wu, Cheng-Keng Chuang

Division of Urology, Department of Surgery, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan

Introduction:

Horseshoe kidney (HSK) is the most common congenital renal fusion anomaly, with anatomical changes leading to impaired urine drainage which would increase the risk for urinary tract infections and renal stone formation, seen in up to 20% of patient. Management of urolithiasis in HSK is challenging due to structural alterations and historically cases were treated with extracorporeal shockwave lithotripsy (ESWL) and percutaneous nephrolithotomy (PCNL). Recently, use of flexible ureterorenoscopy (fURS) and holmium laser lithotripsy in HSK stones had improved surgical outcomes of stone-free rate (SFR) and length of hospital stay. However, literature review shown single-stage SFR 52.9%-85.8% with potential need of second axillary procedure. Considering recent introduction of flexible ureteral access sheath (fUAS) with further increasing SFR in upper tract uroliathisis, we demonstrated a case of right HSK UPJ stone treated by utilizing fURS and fUAS with result of completely stone-free.

Presentation of Case:

        A 45-year-old female patient had past medical history of major depressive disorder, bipolar disorder with history of visual and auditory hallucination under medication control, and unknown anemia. The patient was presented with fever and right flank soreness since 2 months ago. At local hospital, image survey done with KUB, echography and CT scan, which disclosed horseshoe kidney (HSK) with 1.8 x 1.2cm right ureteropelvic junction (UPJ) stone, with stone burden of 109mm² and stone density of 654± 294 Hounsfield unit (HU), with concomitant anatomical anomaly of bicornuate uterus. Due to anatomical complexity HSK, local hospital Urologist offered extracorporeal shockwave lithotomy (ESWL) as 1^st line of treatment; however, after 2 attempts of ESWL, follow up echography and KUB shown treatment failure with intact right UPJ stone measuring 1.6 x 0.8cm. The patient was then referred to our hospital, a tertiary high-volume medical center.

        Due to prior ESWL failure attempts, endourological intervention was discussed at our Urologist OPD and arranged. After admission, pre-operative survey reported normal creatinine level 0.55mg/dL, no leukocytosis (WBC 7.3x1000/μL), and urine analysis of pyuria and microscopic hematuria with bacteriuria. Regular antibiotic was given for treatment of urinary tract infection, with admission obtained urine culture shown growth for Escherichia coli. The procedure was performed with the patient under general anesthesia and lithotomy position, with approximately 20 degrees head-up position. After draping, cystoscopy was introduced to visualize the ureteral orifice which was dilated with metal ureter orifice dilator. Semi-rigid ureterorenoscopy was then performed with successful advancement to stone impaction site, with finding of mild UPJ stenosis at impaction site. Right UPJ stone was fragmented and pushed back by into renal pelvis by Holmium laser lithotripsy. Guidewire was introduced into renal pelvis of HSK under direct vision. A flexible ureteral access sheath (fUAS) 12/14Fr 40cm (Wellead, Guangzhou, China) was placed under guidewire and fluroscopy guidance. Flexible ureterorenoscopy was performed with 7.5Fr scope (HugeMed, Shenzhen, China). All stones were disintegrated with Holmium Laser, utilizing energy 0.5J 40Hz for dusting and 1.6J 10Hz for fragmentation, and all fragments were retrieved from fUAS. Completely stone free was confirmed by visualization of zero stone over all calices and by intraoperative fluoroscopy. Communicating channel to contralateral renal pelvis noted at lower calyx, scope could not pass through. Post-operative double J ureter stent 6Fr 26cm was placed. Follow-up lab at post-operative day 1 disclosed mild elevated WBC 11.9 x1000/μL, hemoglobin 10.3 g/dL, creatinine 0.49 mg/dL, and the patient was discharged smoothly under stable condition with take home antibiotics.

Discussion:

Among anomalous kidneys, horseshoe kidney (HSK), with incidence of 1 in 400, is the most common congenital renal anomaly. HSK is characterized by renal malrotation, potential high ureteric insertion, atypical renal pelvic opening, distorted orientation of calices with atypical ureteral opening into renal pelvis and an increased incidence of UPJ obstruction in one third of the cases. Theres anatomical changes would impact urinary drainage and impair passage of stone fragments after ESWL, PCNL and fURS, indicating higher recurrence of urolithiasis from residual stone fragments. The structural alterations alone could complicate the management of HSK stones with potential influence of SFR and surgical outcomes.

Literature reviews highlighted the potential of fURS in treating urolithiasis in patients with HSK. The stone-free rate achieved with fURS ranged from 77% to 85%, which is comparable to, or slightly better than, that of PCNL and significantly higher than that of ESWL in the context of HSK. With advantages due to its minimal invasive nature and lower risks of major complications comparing to PCNL. Reviews emphasized on usage of ureteral access sheath (UAS) as its usage was associated with higher SFR, probably by assisting to overcome the many anatomical challenges of HSK.

However, SFR was mostly defined as no residual stone fragments greater than 1 to 4mm across studies and when strictly defining SFR by completely absence of residual stone or by single staged surgery with no need of axillary interventions, there was a significant drop to 52.9%-66.6% in case series. The solution to this imperfectness may be the recent introduction of fUAS, with Yu et al. demonstrating further improved SFR and post-operative complication profile while comparing conventional UAS with fUAS. We had demonstrated in our case that with the utilization of the new fUAS, it was possible to irrigated out every single stone fragment achieving a status of completely stone free.

In conclusion, we theorized that the usage of fURS, or concomitant fUAS is a viable and effective alternative for managing urolithiasis in HSK, particularly in patients seeking less invasive option than PCNL and more guaranteed surgical outcome than ESWL. However, rarity of the anomaly making further multicenter and prospective studies difficult to conduct; and current applications would require consideration of anatomical challenges and patient-specific factors, reinforcing the need for expertise in the procedure and a tailored approach to treatment. It is much needed to establish standardized guidelines and redefine the surgical management of urolithiasis in this specific group of patients.

Conclusion: