Preoperative and postoperative risk factors in laparoscopic cholecystectomy converted to open surgery

Material and methods. The records of patients that underwent LC in Malatya State Hospital (Malatya, Turkey) between January 2013 and May 2014 were prospectively examined. One hundred and forty-five patients were involved in this study. The patients were divided into 2 groups: LC patients and patients converted to open surgery. For the patients in both groups, the preoperative age, gender, body mass index (BMI), disease history, previous abdominal operations, and preoperative laboratory findings were recorded, as well as the fact if the abdominal ultrasonography (US) and endoscopic retrograde cholangiopancreatography (ERCP) were performed.


Introduction
Laparoscopic cholecystectomy (LC) is superior to open cholecystectomy because of less postoperative pain, shorter hospitalization duration, shorter time for returning to daily activities, less surgical scarring, and better cosmetic results. 1 The reason for conversion to open surgery during LC is to prevent severe complications that may occur during the operation. 2Conversion to open surgery should not be considered a complication, but as a procedure necessary to complete the operation safely.Knowing the risk factors for conversion to open surgery is important for informing the patient about this topic.
The aim of this study is to determine the risk factors leading to conversion from LC to open surgery.

Material and methods
One hundred and forty-five patients who underwent LC surgery in Malatya State Hospital (Malatya, Turkey) between January 2013 and May 2014 were involved in this study and their data was retrospectively examined.One hundred and forty-one patients were operated on due to choledocholithiasis, while 4 patients were operated on due to gallbladder polyp.The operations were performed by 3 exprienced surgeons in the American position with the classic 4 trocars method.Dissection was performed with a dissector in Calot's triangle.The patients were divided into 2 groups: LC patients and patients converted to open surgery.For the patients in both groups, the preoperative age, gender, body mass index (BMI), disease history, previous abdominal operations, and preoperative laboratory findings were recorded, as well as the fact if the abdominal ultrasonography (US) and endoscopic retrograde cholangiopancreatography (ERCP) were performed.The findings during the operation were also recorded.A >3 mm increase in the gallbladder wall in ultrasonography was considered increased wall thickness (acute cholecystitis).Fasting blood glucose (FBG), number of white blood cells (WBC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP) values were examined and recorded.White blood cells >10,000/mm 3 , AST > 35 IU/L, ALT > 55 IU/L, GGT > 65 IU/L, ALP > 150 IU/L, and FBG > 105 mg/dL values were considered increased.
In all of the patients, the level of abdominal adhesion was evaluated in accordance with the Blauer scoring system (grade 0 -no adhesion; grade 1 -thin and narrow, and easy-to-separate adhesions; grade 2 -thick adhesions limited to a certain region; grade 3 -thick and widespread adhesion; grade 4 -thick and widespread adhesion, adhesion of viscera to the front and back abdominal wall). 3ody mass index < 20 was considered thin, 20-25 was considered normal, 25-30 -overweight, 30-35 -obese, and >35 -morbidly obese.
For statistical analyses, SPSS v. 18.0 software (SPSS Inc., Chicago, USA) was used.Evaluation of risk factors was performed using Pearson's χ 2 test.P-value <0.05 was considered statistically significant.

Results
Of the 145 patients involved in this study, 127 (87.5%) were male and 18 (22.5%)were female.Their mean age was 46.54 years (17-84).While the operation was accomplished laparoscopically in 134 (92.4%) patients, it was converted to open surgery in 11 (7.6%) cases.The reasons for conversion to open surgery are presented in Table 1.No complications were observed during or after the surgery.
It was observed that the conversion to open surgery was statistically significantly more frequent in male patients than in female patients (p < 0.01).Mean BMI of the patients was calculated to be 28.9.The risk of conversion to open surgery was statistically significantly higher in patients in the normal BMI category (p = 0.01) (Table 2).It was found to be statistically significantly higher in patients having chronic disease or increased gallbladder wall thickness in ultrasonography, and in those who underwent ERCP before the operation.The adhesion of the gallbladder to adjacent organs during the operation was found to be a risk factor for conversion to open surgery.According to the Blauer adhesion classification, there were grade 3 or 4 adhesions in all of the patients (11 cases) in case of whom operations were converted to open surgery (p < 0.01).In 75 patients having grade 1 and 2 adhesion and 59 patients having no adhesion (grade 0), the operation was accomplished laparoscopically.Among the reasons that may lead to adhesion, abdominal operation history was present in 31 patients.Conversion to open surgery was performed in only 1 of those patients (Table 3).
It was observed that the risk of conversion to open surgery was statistically significantly higher in patients having a preoperative blood glucose level higher than 105 mg/dL (p = 0.02).Of 17 patients having preoperative leukocytosis, 4 were converted to open surgery and that was statistically significant (p < 0.03) (Table 4).

Discussion
Laparoscopic cholecystectomy is presently the gold standard in surgical treatment of cholelithiasis and gallbladder diseases.But sometimes it may be inevitable to convert it to open surgery to safely end the procedure.Since the first LC in 1987, because of advancements in surgical experience and devices, the rate of conversion to open surgery has decreased gradually.In current publications, this rate is reported to be between 6.3% and 11.5%. 4,5It was found to be 7.6% in our study.
Conversion to open surgery in LC is not a complication, but it may be a necessity to safely end the procedure.The real complications in LC are hemorrhage, perforation of the gallbladder, biliary leakage, biliary tract injury, and organ injury. 6Conversion to open surgery may prevent these potential complications.In order to inform the patient before the operation and to continue the treatment process, it is important to determine the risk factors requiring the conversion to open surgery.
][8][9][10][11] In our study, we determined that male gender and accompanying chronic diseases may be risk factors for conversion to open surgery but advanced age (>65 years) and previous acute cholecystitis attack are not be risk factors.In patients operated on during acute cholecystitis attack, having increased bladder wall thickness and hydropic gallbladder, the conversion to open surgery increased statistically significantly (p < 0.05).
Salman et al. have determined that BMI > 27 might be a risk factor for conversion to open surgery.They have stated that this risk may be caused by increased intraperitoneal fatty tissue.They believe that this increase in fatty tissue may make it difficult to control hemorrhage during the dissection. 11But we determined that in the normal BMI group (20-25) frequency of conversion to open surgery was statistically significant (p < 0.05).High BMI was not found to be a risk factor for conversion to open surgery.
For patients with abdominal surgery history, the problem during LC is intraabdominal adhesions.Although intraabdominal adhesions generally depend on a surgical intervention and they are also seen in cases of peritonitis, endometriosis, pelvic inflammatory disease, long-lasting peritoneal dialysis, radiotherapy, and cancer. 12In many studies, it has been stated that abdominal and epigastrium surgery might be a risk factor for conversion to open surgery. 13,14However, there also are publications stating that it is not a risk factor. 15,16In our study, we determined that prior abdominal surgery was not a risk factor but an adhesion makes dissection in Calot's triangle more difficult and this is a risk factor for conversion to open surgery (p < 0.05).
For patients having pancreatitis attack during the laparoscopic operation or obstruction in the biliary tract, operation after ERCP is recommended. 17The ERCP has been reported to be a risk factor for conversion to open surgery due to the adhesions that may develop after sphincterotomy. 11In our study, we determined that ERCP performed before the operation is a risk factor (p < 0.05).Many authors have reported that preoperative increased WBC, FBG, AST, ALT, ALP, and GGT levels might be a risk factor for conversion to open surgery. 18,19In our study, we determined that high FBG and WBC levels are the risk factors but high AST, ALT, ALP, and GGT levels are not.
Consequently, in our study, male gender, chronic disease history, normal (20-25) BMI level, increased gallbladder wall thickness, high preoperative blood glucose level and leukocytosis, ERCP history, grade 3 or 4 adhesions found during the operation, and the presence of multiple stones in the bladder were found to be statistically significant risk factors for conversion to open surgery (p < 0.05).Knowing these risk factors is important for planning the treatment phases and informing patients before the operation.

Table 1 .
Reasons for conversion from laparoscopic cholecystectomy (LC) to open surgery

Table 3 .
History, physical examinations and intra-operative findings

Table 4 .
Laboratory values