Intraluminal incision and tandem ureteral stenting in obstructive upper urinary tract uropathy

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Introduction
One of the common causes of urinary retention and pain symptoms in urological practice is ureteral stricture. Ureteral stricture is a decrease in the ureteral lumen of various origins, characterized by the phenomena of morphofunctional obstruction of the upper urinary tract (VMP). The etiology of strictures is extremely diverse. An inflammatory process provoked by the presence of a concretion in the ureter or pyelonephritis, as well as a tumor, parasitic, radiation damage, etc., can lead to pathological narrowing of the ureter. The most common causes of ureteral constriction also include medical manipulations. (3) Ureteral stricture occurs in 3-5% of men. (4). The only method of treating ureteral stricture is surgical, and currently the choice and search for the most effective methods of surgical intervention are becoming an urgent issue. In the absence of damage and impaired renal function, reconstructive operations are performed aimed at removing the problem area and restoring urine outflow. They perform: the imposition of a conventional anastomosis, Boari surgery (anastomosis between the ureter and the bladder), replacement flap plastic surgery, ureter plastic surgery with a fragment of the intestine. If there is a severe lesion of the renal tissue with loss of kidney function, the kidney is removed from the ureter. This pathology is polyethological and can be caused by trauma, neoplasm, etc. Laser endoureterotomy is a minimally invasive endourological procedure that can provide lasting results. Surgical treatment is performed transurethrally, i.e. without incisions, through the natural urinary tract. As a rule, excision of the stenosed area of the ureter is performed, followed by plastic surgery and installation of an endotomic stent. (5) Recurrence of strictures of the pelvic ureteral segment occurs in 15-18% of cases and then repeated operations or various endoscopic interventions are required. The cause of recurrence of LMS strictures may be: inadequate resection of the altered area of the ureter, small spatulation of it, as well as poor tightness of the pyelourethral anastomosis. Good drainage of the calyx-pelvic system plays an important role in the success of plastic surgery (6). In order to avoid the occurrence of repetitions of strictures of the upper urinary tract, a method of percutaneous endopyeloureterotomy was proposed. Endopyelotomy is a safe and effective treatment for primary and secondary UPJ obstruction for most patients. The largest experience with the best results in antegrade endopyelotomy is reported (10). Indications for endopyelotomy are as follows: 1-2 stages of hydronephrosis; Normal or moderately decreased renal function; The presence of stricture of the pelvic ureteral segment is not more than 1 cm. The advantages of this type of surgery include: 
1. No incisions – interventions are performed through natural openings;
2. Minimal tissue injury - rapid recovery after surgery;
3. High efficiency of operations;
4. Minimizing the risk of postoperative complications.
The technique consists in puncture of the cup-pelvic system under X-ray or ultrasound control followed by dilation of the puncture canal. Then nephroscopy is performed and the site of narrowing of the ureter is examined, the stricture is dissected with a laser in the lateral direction to prevent vascular damage. At the end of the operation, in some cases, a stent is installed. (1) Percutaneous access in the treatment of VMP strictures has a number of advantages over laser transureterotomy, since in the first case the surgeon has a greater view thanks to a nephroscope, a shorter distance to the object of intervention, and with percutaneous access, relapses occur extremely rarely. To further reduce the likelihood of recurrence in the patient, tandem or double stenting was used. Stenting is a basic, simple manipulation in urological practice. The essence of the manipulation is to install a ureteral stent, which is a thin tube inserted into the ureter to prevent or treat obstruction of urine flow from the kidney. The length of stents used in adult patients ranges from 24 to 30 cm. In addition, stents come in different diameters or calibers to fit ureters of different sizes. The development of stent materials and designs was aimed at reducing stenting-related complications such as pain, discomfort, bladder irritability, and infections.  However, complications associated with stenting are often observed. Two parallel ureteral stents reduce the likelihood of inflection of the ureter and the likelihood of narrowing of the lumen with this stenting technique is reduced. The likelihood of complications with tandem stenting is reduced, since the outflow of urine is constant and this helps to avoid the development of infections and irritation.  This method is effective due to the space between the stents. Urine flow is maintained both through and around stents, which is considered the most important mechanism in stented ureters. (7)
This article demonstrates a clinical case of surgical treatment of a patient with stricture of the pyeloureteral segment of the left ureter complicated by hematuria. 

Clinical observation
Patient X. 31 years old, due to the presence of blood in the urine and hydronephrosis, percutaneous puncture nephrostomy (NPNS) was performed in 2022, plastic surgery of the pyelourethral segment on the left. 
In Swazi, complaining of pulling pains in the lumbar region on the left, the presence of blood in the urine, he was urgently hospitalized in the urological department of the BUZ UR "1 RCB of the Ministry of Health UR" on 17.01.23.  In a hospital setting, a non-functioning stent was removed from the left ureter. The protocol of the operation: a video cystoscopy was performed – the volume of the bladder is 200 ml, the mucosa is not changed. A stent was removed from the left ureter. On 23.01.23, according to the stricture of the pelvic ureteral segment on the left, stenting of the left ureter was performed. The protocol of the operation: the urethra is freely passable. The bladder capacity is 300 ml, the bladder mucosa is hyperemic with pronounced trabecularity. An internal stent No. 6 Sr was installed in the lumen of the left ureter, cloudy urine was released along the stent. Foley catheter No. 18 has been installed. Due to the improvement of the patient's condition, he was discharged in a satisfactory condition.
On 03/18/2013, he was hospitalized in the urological department of BUZ UR "1 RCB of the Ministry of Health UR" in connection with complaints of intermittent pulling pains in the lumbar region on the left, the presence of blood in the urine. According to the ultrasound examination, the cup-pelvic system on the left is expanded, the presence of hyperechoic structures. According to the indications of the stricture of the pelvic ureteral segment on the left, a functioning stent on the left on 03/21/2023, endoscopic removal of kidney stones (lithotripsy), percutaneous endoureterotomy on the left with the installation of two ureteral stents was performed. Operation protocol: under endotracheal anesthesia of the mouth in a typical place, the bottom of the left mouth is visualized, the vesicular part of the stent is removed. A 6CNV ureteral catheter was inserted into the left mouth, position on the abdomen, under X-ray and ultrasound control, a puncture needle was inserted into the pelvis through the middle cup on the left, and a conductor was passed through it. The channel is boosted by dilators, the 16CN port is installed. Antegrade pyelotomy with a tupium laser was performed, 2 internal ureteral stents No. 5 and 6CN were installed. Hemostasis control, nephrostomy drainage was placed in the pelvis, removed through the wound, fixed to the skin, an alcohol asseptic bandage was applied.
Discussion
Open surgery allows the restoration of extended ureteral strictures (up to 15 cm) in the middle and distal thirds using ureteroneocystostomy (with or without antireflux protection) and the Psoas – hitch maneuver, both methods showed promising positive long-term results in 97% of cases with postoperative follow-up for 4.5 years (8).  The frequency of complications in traditional surgical interventions, such as mobilization and reduction of the kidney, Kalpa-deVirda surgery – formation of a flap from the pelvis with subsequent tubularization , trans-uretero-ureterostomy – anastomosis into the side of the ureter from the opposite side, a rather rare operation with strictures of the middle third, Boari operation – cutting out a flap from the bladder, its tubularization (8) is 24%. Recurrence of stricture is the most common complication of conventional surgery. An objective assessment of the recurrence rate after these operations is extremely difficult due to the different definitions of the criteria for the effectiveness of the operation, the timing of follow-up in the long term after surgery, the criteria for recurrence of the disease and the heterogeneity of the groups of operated patients. Some authors believe that in most cases, traditional surgical operations followed by augmentation is a highly effective treatment method in most patients. It is believed that this tactic is effective in 60-90% when observed in a short time after surgery, and when evaluating long-term results, positive results were noted only in 20% of patients (9). 
The postoperative period in the patient from the above clinical case passed without complications. The patient's condition is satisfactory, his consciousness is clear. The skin and visible mucous membranes are clean, of physiological color. Breathing in the lungs is vesicular, there is no wheezing. BPD is 16 per minute. The heart tones are rhythmic, clear, and the pulse is 63 per minute. Blood pressure is 130/80 mmHg. The abdomen has no signs of flatulence, the abdominal wall participates in the act of breathing. Palpationally, the abdomen is soft. The liver does not protrude from under the edge of the costal arch, it is painless. The kidneys are not palpable. The concussion symptom is slightly positive on the left. There is no swelling. Urination is normal. The combination of various techniques aimed at surgical treatment and prevention of recurrence of ureteral stricture shows the most positive dynamics among patients with this urological pathology.  It is the combination of the most minimally invasive and relevant methods that helps to achieve positive results. During his stay in the hospital, conservative therapy was carried out, including drugs: Furamag 100 mg / 3 times a day, Curantil 0.25 mg / 3 times a day, Kanefron 2tab / 3 times a day, a low-salt diet.
The patient was discharged in a satisfactory condition, his ability to work was fully restored, and outpatient monitoring by a urologist at his place of residence was recommended
Conclusions
1. Minimally invasive high-tech operation percutaneous endoureterotomy followed by the installation of tandem stents shows effectiveness in the treatment of recurrent strictures of the upper urinary tract.
2. This operation helps to remove ureteral strictures with fewer postoperative complications compared to conventional surgical interventions.
3. In comparison with open surgeries, the use of endotomic methods can significantly reduce surgical trauma and perform interventions in patients with high anesthetic risk, as well as significantly reduce the time of hospitalization and social rehabilitation.

About the authors

Svetlana N. Styazhkina

Izhevsk State Medical Academy

Email: sstazkina064@gmail.com
ORCID iD: 0000-0001-5787-8269

MD, PhD, Professor, Honoured Worker of Public Health of UR, Honoured Worker of Higher School of RF

Russian Federation, Izhevsk

Dmitry N. Kuklin

Izhevsk State Medical Academy

Email: Kukdn@yandex.ru
ORCID iD: 0000-0002-3265-3650

Urologist

Russian Federation

Pavel G. Sannikov

Izhevsk State Medical Academy

Email: pav.germ@mail.ru
ORCID iD: 0009-0007-8435-1121

Urologist

Ivan N. Semakin

Izhevsk State Medical Academy

Email: sem.uro@mail.ru
ORCID iD: 0000-0002-0299-0429

Urologist

Russian Federation

Arman A. Abramovich

Izhevsk State Medical Academy

Email: arman181990@mail.ru
ORCID iD: 0000-0002-2022-4138

Urologist

Russian Federation

Ruslan S. Gabsalikov

Izhevsk State Medical Academy

Email: gabs.rus@mail.ru
ORCID iD: 0009-0004-7132-2469

Urologist

Russian Federation

Sofia I. Lentsova

Izhevsk State Medical Academy

Email: sonyalenc@mail.ru
ORCID iD: 0009-0005-1048-3629
Russian Federation

Olesya V. Glavatskikh

Izhevsk State Medical Academy

Author for correspondence.
Email: olesya.glav@yandex.ru
ORCID iD: 0009-0005-6378-3641
Russian Federation

References

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