Laparoscopic Drainage Versus Interventional Radiology for Management Of Appendicular Abscess : A Randomized Controlled Trial

Laparoscopic drainage of appendicular abscess has become a novel technique due to its advantages over interventional radiology like complete exploration of the abdomen, exclusion of other pathologies, excision of the appendix at same session, better cosmesis, decrease incidence of wound infection & incisional hernia, better visualization of surgical �eld, �ne handling of edematous tissue and drainage of multiple collections.

Version of Record: A version of this preprint was published at The Egyptian Journal of Surgery on March 22nd, 2024.See the published version at https://doi.org/10.4103/ejs.ejs_288_23.

Introduction
Abscess formation is one of the most serious complications of acute perforated appendicitis with an incidence of 2-10% (1) .In cases of acute appendicitis, the gold standard management is appendectomy, while in the setting of appendicular abscess, the standard treatment is still controversial (2) .The surgical management of appendicular abscess may be complicated with bowel injury, wound infection and paralytic ileus (3) .With the recent advances in interventional radiology, non-operative management of appendicular abscess becomes the trend (4) .Appendicular abscess can be managed by CT-guided drainage trans-abdominal, trans-rectal or trans-vaginal then patients may be later managed with interval appendectomy (5) .Moreover, laparoscopic concurrent appendicular abscess drainage with appendectomy has been established in many centers with the advantages of shorter hospital stay, rapid recovery, better cosmesis and better access and good visualization of operative eld (6) .In the setting appendicular abscess, advantages of laparoscopy over interventional radiology are complete exploration of the abdomen , exclusion of other pathologies and excision of the appendix at same session, while patients, managed with interventional radiology may be still in need for interval appendectomy (7) .In this study, we compare laparoscopic versus interventional management of appendicular abscess regarding advantages, e cacy & safety.

Objectives:
To compare laparoscopic versus interventional management of appendicular abscess regarding advantages, e cacy &safety.

Patients
This prospective randomized controlled clinical trial included all patients who developed the manifestations of appendicular abscess and referred to the Zagazig University Hospital Emergency Department between January 2020and February2022.The study was prospectively approved by Zagazig University Faculty of Medicine Institutional Review Board (Approval Number: 55342/24.1.2020),and was retrospectively submitted in clinicaltrials.gov in 15/6/2022 (ClinicalTrials.govID: NCT05419440).The study was performed in accordance with the code of ethics of the World Medical Association (Declaration of Helsinki) for studies involving human subjects.Written informed consent was obtained from all participants after explaining to them all the study procedures with its bene ts and hazards.Patients'≥16-≤60 years-old, with appendicular abscess, with early sepsis, no septic shock, ASA I &II, no other pathology and candidate for laparoscopy were deemed eligible for randomization.We excluded patients who were < 16->60years-old, septic shock, appendicular mass, ASA > III, previous abdominal operations, intraoperative presence of other pathologies, immune compromised patients, patients with immune suppressive therapy, pregnant patients and not candidate for laparoscopy.
The included patients were simply randomized at a 1:1 ratio to "laparoscopic Group (LG)"or "Interventional Radiology Group (IG)"via the drawing of sealed envelopes containing computer-generated random numbers prepared by a third party before the start of the procedure.
The sample size was calculated by using open Epi program depending on the following data; con dence interval 95%, power of the test 80%, ratio of unexposed/exposed 1, percent of patients with complications after management of appendicular abscess by interventional radiology 15%, and those managed by laparoscopy 2%, odds ratio 8.7, and risk ratio 7.5, So the calculated sample size was 172 patients divided into two equal group.
Primary and secondary outcomes were postoperative incidence of fecal stula and, recurrent collection ,and quality of life in each group during the 3-months follow-up period, respectively.

Diagnosis
After full history taking ( throbbing pain at right iliac fossa several days ago ) and complete physical examination ( uctuant high grade fever especially at evening, severe pain & tenderness at right iliac fossa, toxic manifestations), appendicular abscess was clinically suspected and then con rmed by laboratory investigations(WBC count more than 16000), liver and kidney functions, coagulation pro le, radiological imaging (abdominal US or CT with oral and I.V contrast con rmed the appendicular abscess).There are Criteria for preoperative diagnosis of appendicular abscess and used in diagnosis in cases with negative CT & US ndings constant throbbing pain at right iliac fossa, high grade hectic fever, mass at right iliac fossa felt per abdomen, prolonged diarrhea with nausea & vomiting, increased micturition and tenesmus, high WBC count more than 16000, patients not improving by medications (8) .

Intervention
Laparoscopic group patients were subjected to the following steps after the diagnosis has been con rmed as appendicular abscess.Under general anesthesia, in supine position, ports were inserted, one 10 mm port supra-umbilical (open method or Veress needle), one 5mm port at left iliac fossa, one 5mm port at right iliac fossa.First step was exploration of the abdomen to exclude other pathologies and con rm the diagnosis (we exclude patients with other pathologies after laparoscopic exploration).First step, irrigation & suction of the whole the abdominal cavity with warm saline 0.9%, irrigation with warm saline help in separating the adhesions between the bowels (9) , better visualization of the tissue, Second step was removal of any adhesions.We then gained access to the caecum by tilting the table head down and to left to keep all the small intestine away from caecum, removal of any adhesions with the surroundings by sharp & blunt dissection to gain access to appendicular abscess, drain all the pus by suction and irrigation with warm saline.After complete separation of the appendix from surrounding & complete drainage of pus & removal of all necrotic tissue, removal of the remnant appendix was performed.,In cases with healthy base of appendix,we closed the stump with endo-loop.In cases with unhealthy base, we closed the stump by suturing by ethibond 2/0 in two layers in case with little edema & in ammation of caecum (sutures not cut through) but if there was marked edema and in ammation of caecum and due to severe in ammation and adhesions in the right iliac stula we closed the site of base by omental patch that was xed in place by full thickness sutures in wall of caecum and pass through omental patch.We use the omental patch in our center in attempt to seal perforation and actually, it may help to prevent leakage or stula and it is impossible to cause stula or leak as we used it to cover the site of base of appendix and xed it in healthy tissue like mechanism of sealed perforation by omentum in perforated peptic ulcer.If stula occurred it was not related to omental patch xtion, even if stula was occurred, it is low output stula and close spontaneous within a week provided drainage (10) (11) .
We examined any leak by pressing on caecum and observe any fecal matter leak & air leak test., Finally, irrigation &suction with 2000cc warm saline was performed and a large caliber drain was left in the pelvis to be removed later according to its output.Then patients stayed in hospital under observation till drain removal.
For interventional radiology group, patients were subjected for tube drain or pigtail catheter insertion at right iliac fossa by an interventional radiologist, then daily wash from drain or pigtail catheter using gentamycin & metronidazole till drain output showed clear uid, therefore the drain was removed according the amount of discharge and US con rmed that there is no residual according to interventional radiologist advice (12) .In the failed cases of PC, there was no clear ultrasonic window to the right iliac fossa.we routinely perform interval appendectomy.

Statistical analysis:
Analysis of data was done by IBM computer using SPSS (statistical program for social science version 23) as follows: Description of quantitative variables as Mean, SD, median and IQR.Shapiro test of normality used to check the data distribution.Description of qualitative variables as number and percentage.Chi-square test was used to compare qualitative variables between groups.Fisher exact test was used when one expected cell or more are less than 5.Independent T test was used to compare quantitative between two groups .Mann Whitney test was used instead of unpaired t-test in nonparametric data (SD > 30%mean).Multiple linear regression models conducted to nd predictors to hospital stay.Multiple Binary logistic regressions conducted to nd predictors to quality of life.P value is considered signi cant when it becomes < 0.05 (13) .

Results
This study included 200 patients, 28 patients of them did not met inclusion criteria ( 10 patients had appendicular mass not abscess after laparoscopic exploration, 4 patients were pregnant, 4 patients with intestinal obstruction due to ileus not candidate for laparoscopy or interventional radiology due to distended bowel with risk of injury, 6 patients were diabetic, 4 patient were on immunosuppressive medications ).So the nal number of the patients included in our study was 172 patients divided into equal groups (86 patients in the Laparoscopic group and 86 patients in the interventional radiology group).In our study there was no signi cant difference regarding sex in both groups as shown in table (1).But there was signi cant difference regarding age in both group as shown in table (3).
US & CT ndings of suggestive of appendicular abscess were with no clinical signi cant in both groups as shown in table (1).
The median length of hospital stay in group (1) was 6 (range: 5-7) days with, while in group (2), it was 15 (range: 13-17) days.No patients needed conversion to open surgery or needed further operation to remove appendix in group (1), while in group (2), there were 13 (15.1%)patients needed a completion surgery (either open in 3 patients or laparoscopic in 10 patients), and all patients needed to be subjected for further surgery to remove appendix as in table (2) .
In multiple backward linear regression models, the predictors of prolonged postoperative hospital stay group were being in the intervention radiology group (adjusted B coe cients − 0.873) and being female.
In multiple backward linear regression models, the signi cant predictors of excellent quality of life were patients who underwent perform laparoscopic intervention (OR 7.897).

Discussion
Although Laparoscopic drainage of appendicular abscess has many advantages over the interventional radiology, it has a risk of bowel resection (ileocolic resection) of early surgery for appendicular abscess .it is extremely rare to occur if laparoscopic surgery was done by good experienced hand Laparoscopic drainage of appendicular abscess in a good experienced hand has proven its e cacy & safety without increased incidence of mortality & morbidity (15) .In this study, the complications that occurred, in laparoscopic group included bowel injury in one patient during sharp & blunt dissection of adhesions between the edematous bowel loops by laparoscopic instruments, fecal stula occurred in three patients due to slipped ligature at the base of either nonhealthy or friable appendix.The fecal stulae were managed successfully using conservative treatment.All the stulae closed within one week without any mortality or morbidity.While in interventional radiology group the complications included bowel injury occurred in ve patients, 4 of them with small size abscess, one with moderate size.The bowel injury may have occurred due to lack of experience of interventional radiologist and improper visualization of bowel by US or CT.Recurrence of appendicular abscess occurred in three patient in interventional radiology group due to inadequate drainage and multiloculated abscess.These 3 patients were successfully managed using laparoscopy.Pelvic collection occurred in eight patients in interventional radiology group and were successfully managed using laparoscopy, as well.Mortality occurred in one patient in interventional radiology group due to bowel injury that resulted in sepsis, septic shock with multi-organ failure and death.15,1% of PC drainage patients needed surgery either laparoscopic (10 patients) or open (3 patients as there were not candidate for laparoscopy as they developed ileus) surgery, they needed surgery as there was no improvement in their conditions regarding fever, abdominal pain, vomiting, no decrease in leucocyte count, patients were still toxic, surgery was done immediately .failure of interventional radiology drainage does not mean, radiologists were not experienced, as there are many causes of failure like, multiloculated abscess, cases associated with pelvic abscess also, thick pus and can't be come out through the drain, tip of drain was blocked by necrotic tissue or omentum and distended surrounding bowel (16) .So failed interventional radiology drainage is not dangerous and can be well treated by surgery either open or laparoscopy-this is an important part of the message.
The length of hospital stay in laparoscopic group was shorter than interventional radiology because in laparoscopic group we removed the source of sepsis, peritoneal wash, therefore helped thepatient to recover rapidly.However, in interventional radiology group, we placed US or CT guided drain and waited several days for the pus to come out and daily wash with metronidazole and garamycine, so this prolonged the time needed for the patients to recover and all over length of hospital stay.The cost in laparoscopy group is less because the patients had shorted length of hospital stay but in interventional group, patient needed longer hospital stay for close observation and another admission, later on, for interval appendectomy.In our study, in interventional radiology group, 13 patients needs surgery immediately as they were not improved, the remaining patients during period of follow up, some of them still complain with recurrent attack of pain at right iliac fossa which improved by analgesics ( chronic appendicitis) but without toxic manifestations, US or CT nding reported remnant appendicular stump, they were subjected to elective laparoscopic appendectomy In good experienced hands in laparoscopy, the conversion to open is extremely rare and we did not experience any conversions, while in interventional radiology group, there were 13 patients converted to surgery either laparoscopic or open surgery as the abscess was in accessible or small in size.According to World Journal of Emergency Surgery guidelines: Regarding non-operative treatment of acute appendicitis, antibiotic therapy can be successful in selected patients with uncomplicated appendicitis who wish to avoid surgery and accept the risk up to 38% recurrence.Percutaneous drainage of a periappendiceal abscess, if accessible, is an appropriate treatment in addition to antibiotics for complicated appendicitis.Non-operative management( Percutaneous drainage plus antibiotics ) is a reasonable rst line treatment for appendicitis with phlegmon or abscess.Operative management of acute appendicitis with phlegmon or abscess can be a safe alternative to non-operative management but only in experienced hands (17) .
The quality of life was better in laparoscopic group ,criteria that were used to assess the quality of life were absence of recurrent pain at right iliac fossa, patients without any discomfort and needs for further management (18) .

Conclusion
Laparoscopic management of appendicular abscess can be safely applied in a good experienced hand with no mortality & morbidity, without the need for interval appendectomy.

Table 1 .
Demographic criteria, clinical presentation, US&CT nding, size of appendicular abscess in both group.

Table 3 .
Hospital stay & age in both groups.

Table 4 .
Quality of life in both groups.