The article provides statistics on the volume of surgical interventions on the extrahepatic bile ducts, the number of iatrogenic cicatricial strictures after traditional and laparoscopic cholecystectomies. The authors also provide figures of complications and mortality after various reconstructive and reconstructive interventions for iatrogenic strictures of the extrahepatic bile ducts. The article highlights the causes of hepatic choledochus strictures. 

Particular attention is paid to the increase in these complications after laparoscopic cholecystectomy. The article describes the classification of the level of cicatricial stricture of hepaticoholedoch according to E.I. Halperin and N.F. Kuzovlev, which is most convenient for practical application. The results of various reconstructive and reconstructive operations with iatrogenic strictures of hepaticoholedoch are critically evaluated and the importance of new, modern minimally invasive methods is emphasized. It is also emphasized that, despite the introduction of high-tech minimally invasive methods of diagnosis and treatment in surgical hepatology, and the progress in reconstructive surgery of the biliary tract, only the evaluation of the long-term results of treatment in this category of patients can give an objective assessment of the correctness of the chosen direction.

The increase in the incidence of cholelithiasis, as well as the improvement of biliary tract surgery in recent decades, has led to a significant increase in the number of surgical interventions performed. About 7.000-8.000 operations on the organs of the biliary system are performed annually in Uzbekistan, over 400.000 operations are performed in the CIS countries and, according to WHO, about 2.5 million in the world. Since operations on the biliary tract are now performed in almost all hospitals by surgeons of various qualifications, this leads to an increase in the frequency of various complications, including iatrogenic injuries that cause the formation of cicatricial strictures of the extrahepatic bile ducts [1;2; 5;9].

One of the most difficult problems of biliary tract surgery is the treatment of patients with injuries and cicatricial strictures of the bile ducts. Thus, according to several authors, the frequency of bile duct injury is 0,25-3,2% of the total number of operations on the biliary system, and mortality at reconstructive and restorative interventions reaches 17-55%, post-operative stricture recurrences occur between 5,3% and 37% of cases [1;6;7;11]. In 92-97% of cases the cicatricial stricture formation is a consequence of iatrogenic bile duct injury, inaccurate surgical manipulations on the duct during the execution of cholecystectomy. The same problem can be caused by stricture development at the choledochotomy hole at application of rough suture material and non-atraumatic needles. 

In addition, choledochal scars can occur at incorrect selection of the diameter of the drainage, trauma during its removal, when the drainage is fixed with non-absorbable sutures, or when the wall of the choledochus is roughly sewn to the drainage tube. Rarely, strictures are congenital or result from primary sclerosing cholangitis [2,3,5,14,15,19,20]. 

Among the causes of bile ducts damage are misunderstanding of their anatomical structure due to edema or infiltration of the hepatoduodenal zone, cystic or hepatic ducts anomalies, and insufficient experience of the surgeon.

The widespread method of laparoscopic removal of the gallbladder caused occurrence of cicatricial strictures of hepaticocholedochus, especially at the stage of mastering this method. The frequency of iatrogenic injuries of the bile ducts in recent decades has been stably kept at the level of 0.05-0.2%, and the use of laparoscopic cholecystectomy increases this figure to 0,25-3,5% [6; 7].

Cicatricial strictures of the bile duct may also occur due to bile leakage caused by a thermal burn, when a biliary cyst is isolated from the cervix or an injury to the wall of the hepaticocholedochus in the postoperative period. In addition, inadvertent clipping of the cystic duct or cystic artery can lead to partial or complete compression of the bile duct, especially in congenital bile duct anomalies.

Leading hepatologists have long considered that the greatest difficulties of surgical interventions are observed in the treatment of patients with cicatricial strictures of the bile ducts [1, 9, 23]. However, recent decades show that along with the significant development of medical science and surgical technology, including in hepatobiliary surgery, the most complex interventions occurred in the liver and extrahepatic bile ducts in a wide variety of diseases. The development of such techniques as liver transplantation, surgery of liver tumors and cysts, endovisual and radioendovascular surgery, the use of new surgical materials also poses a number of tasks related to the elimination of inevitable complications.

Despite careful study and development of reconstructive hepatobiliary surgery, many issues in this direction are far from being solved, and some of them are in their infancy. This is especially true for iatrogenic cicatricial lesions of the biliary tract [23, 30, 39, 40].

Statistics show that the incidence of bile duct injury in open cholecystectomy is approximately 1:400 [37]. A similar frequency was observed with laparoscopic cholecystectomy (1:200-1:400) [36, 40]. According to different authors, lethality in reconstructive interventions reaches 14-55% [16, 30, 40].

Leading hepatologists point out that the least lethality can be achieved using the principle of preventing diseases of the liver and biliary tract and preventing the development of severe consequences of surgical interventions in this anatomically sensitive area [21, 31].However, unfortunately, the leading hepatological centers continue to accumulate new clinical data on the treatment of patients with biliary strictures, which forces us to constantly and critically rethink our views on the key issues of this problem.

Restoring the function of normal bile secretion is a great difficulty. The main reasons for the difficulty are gross violations of topographic and anatomical relationships and adhesions in the hilum of the liver, a severe general condition of patients due to prolonged obstructive jaundice and recurrent purulent cholangitis [12, 19].

The tactics of surgical treatment of this most difficult group of patients have repeatedly become the subject of discussion at numerous conferences and symposiums. As a result, significant progress has been achieved in reconstructive surgery of the biliary tract, associated primarily with the active introduction of modern methods of radioendovascular and endoscopic surgery, the use of precision technologies and biomaterials [18, 38]. 

However, despite this, reconstructive operations on the biliary tract are accompanied by the development of narrowing of the biliary-intestinal and biliary-biliary anastomoses in 4-27% of cases [19], nullifying the results of reconstructive surgery and aggravating the severity of the patients' condition. In the long term, the main cause of unsatisfactory results of reconstructive operations on the biliary system is reflux cholangitis, leading to restenosis and cholangiolytic abscesses [3, 13, 30]. The frequency of cholangiolytic restriction in the long-term follow-up period is 8.4-28.3% [23]. A smaller percentage in the structure of complications is occupied by relapses of cholelithiasis, cholangiogenic liver abscesses, and biliary sepsis.

In this regard, such issues as the choice of the optimal technology for reconstructive and restorative interventions, indications for transhepatic drainage of the bile ducts and determination of the role and place of endoscopic correction methods remain relevant. At the same time, it must be recognized that an objective assessment of the correctness of the chosen direction can only be given by studying the long-term results of treatment of this category of patients.

Diagnostics of patients with cicatricial strictures of the bile ducts is aimed at establishing the causative factor, the level of stricture, the extent of the affected area, determining the state of the bile ducts above and below the level of destruction.

To bring into order the terminology that describes the level of bile duct strictures, many classifications have been proposed. To date, the most convenient classification is by H. Bismuth (1982). According to it, cicatricial strictures are divided into five types: type 1-2 - low strictures and type 3-4-5 - high strictures. However, the author does not touch upon the details of the location of the narrowing site in the proximal segments in the region of the hilum of the liver, which sharply reduces the possibility of using this classification when choosing the optimal method for reconstructing the bile ducts above the bifurcation.

The most reasonable and practical is the classification by E.I. Galperin and N.F. Kuzovlev [9], who divide cicatricial strictures as follows:

• Stricture type 0 (type zero) (free segment of the common hepatic duct less than 1 cm or confluent stricture)

1. Bifurcation

2. Subbifurcation (subconfluent)

3. Monoductal

4. Biductal

• Type 1 strictures (the length of the free segment of the common hepatic duct is from 1 to 2 cm)

• Type 2 strictures (the length of the free segment of the common hepatic duct is at least 2 cm).

In addition to considering the levels of location and extent of choledochal strictures, some authors propose to supplement the classification with clinical factors. Ratchik V.M. and others. [24] offer a modified classification of Shalimov A.A. [29] taking into account clinical and anatomical features. According to the etiology, the authors separate iatrogenic strictures (anamnesis of surgery), inflammatory strictures (cholelithiasis, chronic pancreatitis, peptic ulcer, etc.).

By localization: low (supraduodenal part of the choledoch), medium (hepaticocholedoch area), high (lobar hepatic ducts - the gate area of the liver). 

By prevalence of duct lesion: 1st degree - less than 2 cm, 2nd degree - less than 3 cm, 3rd degree - more than 3 cm.

By cholestasis intensity: partial (transitory bilirubinemia of up to 50 micromole/l, moderately increased alkaline phosphatase), total (refractory bilirubinemia of more than 50 micromole/l). 

By clinical course: stage of formation of cicatricial stricture (narrowing of the ducts from 1/3 to 2/3 of the diameter) - is characterized by cholangitis occurences, intermittent jaundice, stage of evident signs (narrowing of ducts over 2/3 of the diameter) - characterized by jaundice, skin itching, cholangitis, multiple organ failure [8].

To date Endoscopic retrograde cholangiopancreatography (ERCP) is considered the optimum method of investigation of extrahepatic bile duct. This method allows to fully investigate all segments of bile-excreting system. If in some cases ERCP is impossible, then it is complemented by percutaneous transhepatic cholangiography (PTC) which significantly supplements the information on the status of the bile ducts. 

Great value in the study of bile duct strictures is also contributed by magnetic resonance imaging, multislice computer tomography with biliary tract contrasting. Magnetic resonance cholangiopancreatography, being a non-invasive technique of visualizing the bile ducts, has gained popularity in recent years as an accurate method of assessing biliar anomalies [12, 32].

It is assumed that the successful solution of the issues of reconstructive surgery of the biliary tract directly depends on the quality of preoperative diagnosis, a detailed study of the nature, mechanisms of development of pathological processes. Along with this, in many cases, the results of the diagnostic method are studied outside of their pathogenetic connection and interdependence. This causes a number of discussions and creates certain difficulties in formulating the optimal solution.

Currently, hepatologist surgeons indicate a number of problems associated with the surgical correction of cicatricial strictures of the bile ducts:

1 - the possibility of reconstructive operations by performing biliary anastomoses or surgical intervention using autovenous inserts or allogeneic materials;

2 - the need to use frame drainage for the application of BDA;

3 - types of frame drainages, the duration of their stay in the biliary tract, the diameter of the tube and the material for its manufacture;

4 - benefits of using BDA or KDP for the jejunum;

5 - choice of the optimal method of reconstructive and restorative operations in case of damage to the duct, the timing and stages of these operations;

6 - the role and place of X-ray and endoscopic techniques in the correction of cicatricial strictures of the bile ducts [4, 7, 11, 21].

Each case that a surgeon encounters in such situations during surgery is strictly individual, what forces him to choose the optimal way out of a number of surgical intervention options [14, 15].

In order to improve the immediate and long-term results of operations and prevent digestive-biliary reflux, in recent years various operations have been proposed based on the formation of valves in the area of anastomoses between the biliary tract and various sections of the gastrointestinal tract.

This technique still attracts the attention of many surgeons and requires new experimental clinical studies. This, apparently, is the reason for attempts at antireflux surgery and the development of the so-called "areflux" BDA with the formation of valves between the biliary tract and the small intestine.

At the same time, the role of pathological reflux is still being discussed [17, 31].

One of the promising areas of reconstructive surgery for cicatricial strictures is the use of various materials and allogeneic biotransplants.

Surgical interventions performed at elderly patients with severe comorbidities for emergency indications, are accompanied by a large number of complications, and mortality reaches 14-32%. In this regard, in recent years, there has been an increasing interest in non-invasive methods for restoring bile secretion and, first of all, in endoscopic interventions. Currently, endoscopic methods of diagnosis and treatment play an important role in diseases of the hepatopancreabiliary system. Taking into account the therapeutic possibilities of endoscopic methods, along with traditional methods of sanitation of hepaticocholedochus and restoration of adequate passage of bile, such as EPST, nasobiliary drainage, new endoscopic interventions are widely used in clinical practice: mechanical lithotripsy, duodenobiliary drainage of hepaticocholedochus using transpapillary endoprosthesis, diathermic expansion of a narrowed BDA and cicatricial strictures of the bile ducts [27, 35].

The use of these methods allows to easily and quickly prepare patients with symptoms of MF, purulent cholangitis, PPN for upcoming planned or delayed surgical interventions. In most cases, the above endoscopic interventions can be an alternative to surgical interventions [26, 27].

By now, it has become obvious that, despite the introduction of high-tech, minimally invasive diagnostic and treatment methods into surgical hepatology, as well as the progress of reconstructive surgery of the biliary tract, only the study of long-term results of treatment of this category of patients can provide an objective assessment of the correctness of the chosen direction.