Characteristics of Trocar Site Hernia after Laparoscopic Cholecystectomy

Trocar site hernia (TSH) is an incisional hernia occurring at the trocar insertion sites after different types of laparoscopic surgeries. The aim of this study is to present characteristics of patient and surgery series with trocar site hernia after laparoscopic cholecystectomy. A 2930 consecutive patients underwent laparoscopic cholecystectomy in two major university- affiliated hospitals from April 2014 to March 2018 and the patient followed up for variable periods of time. Retrospective medical chart review to study trocar site hernia including patient, operation, instruments, and pathologic characteristics described. Six patients had trocar site hernia (incidence 0.20%), the hernias occurred mostly at the umbilical port site after using 10 mm trocar. Risk factors included mainly obesity, female gender and use of 10 mm trocars at midline sites. TSH is more described. It occurs mostly at the umbilical port site. Major risk factors include obesity, diabetes mellitus, lengthy procedure, extension of entry site, and wound infection. Closure of fascial defect is supposed to reduce the incidence despite weak evidence.


Methods
This is a retrospective medical records review of 2930 consecutive patients underwent LC for GBSD in two Mutah University College of Medicine -affiliated hospitals: Al Bashir Hospital in Amman, and Al Karak Governmental Teaching Hospital, Karak, Jordan from April 2014 to March 2019. The research methods were carried out in accordance with Scientific Research Committee in the College of Medicine in Mutah University guidelines and approved by the Institutional Review Boards (IRB) Committee on Ethics in Scientific Research in the College of Medicine in Mutah University: All patients signed informed consent to use medical information for scientific research on admission. The patient's exclusion criteria were age younger than 18 years, conversion to open cholecystectomy, pre-existing umbilical hernia, immunodeficiency disorders, re-operation due to other complication of LC than TSH, and patients lost to follow up. Studied variables included patient related factors: age, sex, weight, co morbidities, hernia site and gall bladder pathology; surgery related factors: elective versus emergency, trocar size used at hernia site, entry technique, intraoperative bleeding, operation time, and closure of fascial layers.
The LC surgeries were performed by three surgical teams. In all, but one patient, the closed technique was used to establish pneumoperitoneum, bladeless and bladed trocars used. A transverse, infra-umbilical, 1-2 cm long skin incision was made and a −10 mm reusable trocar was inserted into the peritoneal via a vertical incision along the linea alba and the peritoneum. After inserting the first trocar and establishing pneumoperitoneum of 14 mmHg, two more plastic bladed trocars, 10 and 5 mm, were introduced under direct vision through incisions just below the xiphoid and at the right midclavicular line, 4-6 cm below the costal margin, respectively. A fourth 5 mm trocar was inserted at the right anterior axillary line, 6-8 cm below the costal margin. After complete dissection of the gallbladder, it was retrieved through the infra-umbilical incision. The fascia at the infra-umbilical incision was sutured with interrupted Prolen sutures No. 0 in the patients presented with acute cholecystitis. The fascia was sutured at sites of 10 mm ports with Prolen or Vicryl No. 0 but not at sites of 5 mm ports. Operation time, pathology reports, and hernia occurrence recorded for all patients. The TSH was diagnosed clinically in all patients.

Results
From April 2014 to March 2018, a total number of 2930 patients underwent LC for GBSD in two university -affiliated hospitals by three surgical teams. The operative procedure was the standard LC procedure. Six patient developed TSH at different periods of follow up that represents an incidence of 0.2%. No one of the patient was old. The median age of the patients was 41.8 years(31-55years). The male: female ratio was 1:2. Two female patients were hypertensive, and one of them, the patient who presented acutely, had also sleep apnea (SA). Obesity, defined as body mass index (BMI) > 30 found in 66.7% of patients. The patient demographics and operative findings are presented in Table 1.
The mean operative time was 41.8 minutes (range 20-120 minutes). The longest duration was for the emergency LC for acute cholycystitis. There was no need to extend the fascial opening to extract the gallbladder in any patient. None of the LC was associated with intra operative bleeding or bile duct injuries. All patients had multiple small GBS, except the patient with acute cholecystitis who had single large stone. No tumors or polyps found the GB specimens. The earliest patient to present with TSH in this series was the patient who presented acutely and had the longest operative time. The remaining patients presented within one year of surgery. No patient presented with evisceration. One third of the hernias occurred in the epigastric port site, the remaining occurred in the umbilical port site. Most of them presented with painless slowly growing mass at the trocar site, not associated with acute or obstructive symptoms. The content of the hernia sac was omentum. The TSH was repaired electively with simple anatomic repair.

Discussion
LC is the most common laparoscopic procedure performed worldwide, and like other types of laparoscopic surgery, it is responsible for the development of a new type of incisional hernia occurring at the insertion site of the trocar, the so-called trocar site hernia (TSH) as defined by Crist and Gadacz 4 . However, the term 'port site hernia" used to describe the same clinical situation in other reports. The development of incisional hernia after classical major laparotomy is a well-known complication. However, the development of incisional hernia after laparoscopic surgery is much less common with a prevalence reported to be less than 1% in different series [6, 7, and 8]. The available data is scant and came mostly from retrospective studies with ill-defined follow-up periods and study cut points. The incidence of TSH after LC is controversial; earlier reports described this complication as extremely rare, while many recent publications mentioned it as very common. Table 2 summarizes various incidence results from different series worldwide over the last two decades.
The incidence in this series was similar to that of Voyles et al. series 6 . The highest incidence reported is 25.9% in Comomajuncosas et al. series 7 with a conclusion that the incidence is actually was higher (47.4%) due to the presence of asymptomatic TSH cases detected after thorough physical examination. We expect that TSH incidence will be higher if patients are not lost to follow up and if imaging modalities are used to investigate equivocal clinical findings. TSH occurs primarily at the umbilical trocar site because most trocars used in the umbilicus are large 8 , or probably umbilical hernia was there before laparoscopic operation 9 . In this report, two-third of cases occurred at the umbilical trocar site.

Pt.
Different risk factors for TSH such as age, female gender, diabetes, obesity (BMI > 30), type of cholecystitis, extension of umbilical incision, trocar size, trocar site, wound infection, duration of surgery, preexisting hernia, non closure of trocars site defect, poor muscle relaxation during reversal of anesthesia before trocar removal were analyzed using univariate and multivariate statistical analysis in variable retrospective and prospective cohorts. All of the previous factors were found significant on univariate analysis. However, on multivariate analysis the list of significance was shortened to advancing age (>70), BMI > 30, duration of surgery, diabetes mellitus, incision enlargement, and wound infection as detailed in Table 3 7,10,11 .
Obesity causes chronic increase in intra abdominal pressure and weakness of the abdominal wall musculature. However, we believe that the hernia will be more obvious if the patient loses weight due to the reduced buttressing effect of the subcutaneous fat. Although no statistical inference can be drawn from this series due to the small sample size, nonetheless, few benchmarks deserve attention such as the most of the cases are in females, and most the patients are obese, and all the hernias appeared in the midline trocars at trocar size of 10 mm. Most of the cases were chronic cholecystitis due to multiple GBS, and the only case with single stone presented with acute cholycystitis. The presence of malnutrition or cholecystitis was suggested as possible risk factors for TSH in some reports without statistical analysis 8,12 . Two of our patients were hypertensive and no one proved diabetic at time of surgery or during follow up. The hernia content can be omentum and/ or bowel hence the variation in the clinical manifestations from asymptomatic and discovered by ultrasound or CT scanning to mild pain and slowly growing mass indicating omental entrapment, whilst severe pain and change of skin color over the mass indicates early complication such as omental infarction or bowel incarceration and obstruction 13 that requires emergency surgery in about 15% of patients 14 . In this series the entire patients present with early pathologic stage without complication. No intestine was entrapped in the hernia sac. The clinical onset of TSH can be early as one month post operative or years later. The surgical treatment depends on the presentation and intraoperative findings. Closure of the fascia was suggested to reduce the incidence of TSH. However, it is still a controversial issue. In this series the fascia was closed at 10 mm or more port sites. Some authors suggest the routine closure of fascia entrance of 10 mm or larger trocars 15,16 while others find this unnecessary step 17,18 . New trend suggest sclosing the fascia with mesh in certain high-risk patients 19 .  Table 3. Multivariate analysis of risk factors for TSH.