Clinical data of all patients, that underwent surgery for retrocaval ureter from December 2013 to January 2020 and the study of this data was done from June 2020, at Urology Department IPGMER Kolkata, were retrospectively analysed. Institutional Ethical Committee approved the study (Approval no.- IPGMER/IEC/2020/109).

Patients were divided into two groups- open surgery group and transperitoneal laparoscopic surgery group, depending on the type of surgery they underwent. Preoperative, intraoperative and postoperative characteristics were compared in both the groups- age, gender ratio, operative time in minutes, estimated blood loss in millilitres, numbers of days for which analgesics were required, time after which drain was removed postoperatively and hospital stay.

Operative time was defined as the time interval between incision to completion of surgery in minutes. Estimated blood loss was calculated by adding the suction output to the difference of wet and dry mop. Analgesic requirement was counted as the number of days before the patient was pain free or had minimal pain not requiring analgesic drugs in the postoperative period. Intravenous infusion of 1 gram paracetamol was given eight hourly on the day of surgery followed by tablet paracetamol 650 milligram eight hourly till the patient was pain free. Drain was removed when the drain output was less than twenty millilitres. Hospital stay was defined as duration from the day of surgery till the discharge of patient. Patient case records were looked into to see the various imaging modalities used to clinch the diagnosis. Imaging modalities included Ultrasound Kidney Ureter Bladder (USG KUB), X-ray KUB, Intravenous Urogram (IVU), Retrograde Pyelogram (RGP) and Computed Tomography Urogram (CTU). Hydroureteronephrosis revealed by IVU was also noted wherever found and graded [9]. The collected data was compared between the two surgical groups [10,11] and position and type of ureter was also noted as relevent data for surgical outcome [12].

Two sample t-test was used to compare the intraoperative and postoperative parameters in the two groups. Statistical significance was set at a p-value of less than 0.05. Data obtained in both the groups were analysed using the software SPSS Version 24.

Fifteen patients underwent surgery for retrocaval ureter during the study period. Patient’s age ranged from 21 years to 45 years, with a mean of 32.5 years. Patients presented with symptoms ranging for a duration of 4 months to 24 months. Clinical manifestations chiefly consisted of repeated right loin pain, intermittent haematuria, urinary tract infection and right loin swelling/fullness. All patients were offered USG KUB, X-ray KUB and IVU initially. RGP and CTU were offered to patients having diagnostic uncertainty. Subsequently, ten patients had undergone RGP while five patients had their CTU done. USG revealed right renal calyceal, pelvic and proximal ureteric dilatation in all patients. IVU revealed mild to moderate hydronephrosis in eleven patients while four patients had severe hydroureteronephrosis [9].

Imaging showed the right ureter to be displaced to the median line before the 3^rd to 4^th lumbar vertebrae giving the appearance of a typical S or reverse J sign. CTU revealed right hydronephrosis, dilatation of right proximal ureter. Ureter was found to be coursing medially posterior to the inferior vena cava. All fifteen patients in this study had type 1 retrocaval ureter [12]. The demographic and perioperative characteristics of patients in both the groups were compared as shown in [Table/Fig-1,2]. The chief perioperative characteristics under evaluation consisted of operative time, estimated blood loss, analgesic requirement, drain removal and duration of hospital stay.

Open surgery was successfully performed in seven patients. A statistically significant difference was seen in all the perioperative parameters as depicted by p-value obtained in [Table/Fig-2] Superficial surgical site infection was seen in two patients prolonging their hospital stay. Postoperative follow-up ranged from 12 months to 36 months. In the follow-up period, patients were symptom free without any complications.

Transperitoneal laparoscopic surgery was performed successfully in eight patients. Patients in this group consisted of three males and five females. [Table/Fig-2] clearly shows the superiority of laparoscopic surgery over open surgery in terms of less blood loss, lesser requirement of analgesia, earlier drain removal and shorter hospital stay as evidenced by statistically significant p-value. While the operative time in this group of patients was significantly prolonged in comparision to open surgery group. Postoperative follow-up ranged from four months to three years. Stent removal was done at six weeks. Thereafter, patients had no complains during the entire follow-up period.

The observations of this study support transperitoneal laparoscopic surgery as the most suited option for definitive management of retrocaval ureter as depicted by shorter operative time, less blood loss, lesser requirement of analgesia, earlier drain removal and in turn markedly reduced hospital stay and thus enabling the patient to return to their normal lifestyle much earlier as supported by statistically significant p-value [Table/Fig-2].

Mao L et al., published a similar study comparing retroperitoneal laparoscopic surgery and open surgery. Retroperitoneal approach enables direct access to kidney thus reducing the incidence of complications but it is challenged by a steeper learning curve. Their findings were similar to the findings of this study advocating laparoscopic surgery over and above open surgery [10].

In this study, all cases had retrocaval ureter on the right side as is the case more often than not. Thirugnanasambandam V et al., reported a case of isolated left retrocaval ureter with a single left sided IVC without situs inversus [11]. In 1982, Bergman classified retrocaval ureter into two clinical types [12]. Type 1 (low loop) is more common, with the dilated proximal ureter resembling a reverse J. Type 1 retrocaval ureter usually presents with obstructive symptoms. In Type 2 (high loop), the ureter passes behind the IVC at the level of pelviureteric junction thus causing minimal or no hydronephrosis [12].

Mugiya S et al., provided the first report of retroperitoneoscopic intracorporeal ureteral anastomosis using automatic suture device to correct retrocaval ureter [13]. Recently, Laparoendoscopic Single Site (LESS) Surgery has been introduced to further improve cosmesis and reduce morbidity. Abdel-Karim AM et al., described the use of LESS for the treatment of retrocaval ureter in a morbidly obese female. Their study clearly mentions, though Laparoscopic Endoscopic Single-site Surgery (LESS) offers a good cosmesis with minimal scar it has its own drawbacks like collision of instruments, lack of triangulation and in line vision making suturing extremely difficult [14]. Kumar S et al., performed single incision multiport laparoendosopy to repair retrocaval ureter using ureteric tacking fixation technique which makes suturing easy and rapid by conventional laparoscopic instruments [15].

Here again the major issue is the limited manoeuvrability of instruments leading to difficulty in suturing and thus prolonging the operative time. Yen JM et al., reported conservative management of two cases of retrocaval ureter with significant proximal hydroureteronephrosis and suggested immediate surgical repair is not always warranted [16]. In contrast to the findings of Yen JM et al., the present study believes early surgical intervention is required once the patient becomes symptomatic.

In this study, transperitoneal laparoscopic end-to-end uretero-ureterostomy was performed in eight cases for definitive management of retrocaval ureter. As is evident from this study, transperitoneal laparoscopic approach fared much better than open approach in all aspects. Also, when compared to retroperitoneal laparoscopic surgery, transperitoneal approach appears to be much simpler owing to familiar anatomy and a larger working space. Even robotic surgery does not offer any great advantage over laparoscopic technique apart from the ergonomic ease for the surgeon [8]. Though LESS and single incision multiport laparoendoscopic surgeries offer better cosmesis but only at the cost of poor ergonomics, limited maneuverability and difficult suturing [14,15].

Firstly, the sample size was small and secondly, the follow-up was also short.

Transperitoneal laparoscopic end-to-end uretero-ureterostomy as a definitive treatment of retrocaval ureter is safe, effective and reliable option with less trauma and faster recovery. This minimally invasive technique can be considered as the first choice for treatment of retrocaval ureter even at the hands of relatively less experienced laparoscopic urologists on account of better orientation via familiar anatomical landmarks and shorter learning curve. Further studies with a larger sample size and a longer follow-up are needed to strongly support the conclusions drawn from this study.