The Treatment of Periappendicular Abscess After the Acute Phase

Study Overview
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Brief Summary
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The PeriAPPAC trial is a prospective randomised study comparing interval laparoscopic appendectomy with follow-up MRI in patients with initially successfully treated periappendicular abscess. Periappendicular abscess is generally initially treated conservatively with antibiotic therapy and if necessary, drainage. Operative treatment in the acute abscess phase is associated with increased morbidity and thus complicated appendicitis with a periappendicular abscess is initially treated conservatively. However, there is debate on whether interval appendectomy is required. After initial successful conservative treatment of a CT- or MRI-diagnosed periappendicular abscess, patients enrolled in the PeriAPPAC study are randomised either to interval appendectomy or to follow-up with MRI at two months after the initial treatment. All patients also undergo a colonoscopy, appendectomy patients prior to surgery and MRI patients after the MRI (outpatient visit at endoscopy unit with information on the MRI). The primary endpoint is the treatment success in both treatment arms. In the interval appendectomy evaluated as possible morbidity related to appendectomy and in the follow-up treatment arm as possible recurrence of the appendicitis and/or abscess during a one-year follow-up. The PeriAPPAC study is a multi centre trial and the participating hospitals are Turku University Hospital, Oulu University Hospital, Tampere University Hospital, Kuopio University Hospital and Seinäjoki Central Hospital.

Detailed Description
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The PeriAPPAC trial is a prospective randomised study comparing interval laparoscopic appendectomy with follow-up MRI in patients with initially successfully treated periappendicular abscess. Periappendicular abscess is generally initially treated conservatively with antibiotic therapy and if necessary, drainage. Operative treatment in the acute abscess phase is associated with increased morbidity and thus complicated appendicitis with a periappendicular abscess is initially treated conservatively. However, there is debate on whether interval appendectomy is required. After initial successful conservative treatment of a CT- or MRI-diagnosed periappendicular abscess, patients enrolled in the PeriAPPAC study are randomised either to interval appendectomy or to follow-up with MRI at two months after the initial treatment. All patients also undergo a colonoscopy, appendectomy patients prior to surgery and MRI patients after the MRI (outpatient visit at endoscopy unit with information on the MRI). The primary endpoint is the treatment success in both treatment arms. In the interval appendectomy evaluated as possible morbidity related to appendectomy and in the follow-up treatment arm as possible recurrence of the appendicitis and/or abscess during a one-year follow-up. The PeriAPPAC study is a multi centre trial and the participating hospitals are Turku University Hospital, Oulu University Hospital, Tampere University Hospital, Kuopio University Hospital and Seinäjoki Central Hospital.

Official Title
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The Treatment of Periappendicular Abscess After the Acute Phase (PeriAPPAC): a Randomized Clinical Trial Interval Appendectomy Versus Follow-up

Conditions
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Periappendicular Abscess

Intervention / Treatment
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* Procedure: Interval appendectomy
* Procedure: Follow-up with MRI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-60 years CT- or MRI-diagnosed periappendicular abscess, that has initially undergone successful conservative treatment with antibiotic therapy and drainage, if necessary Exclusion Criteria: Suspicion of a tumour on CT or MRI Age under 18 years or over 60 years Pregnancy or lactating Allergy to contrast media or iodine Renal insufficiency Metformin medication (DM) Unsuccessful initial conservative treatment of periappendicular abscess Lack of co-operation (unable to give consent) A severe medical condition Previous acute appendicitis treated conservatively with antibiotics

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Interval Appendectomy<br>The periappendicular abscess, diagnosed by a CT-scan or MRI, is initially treated conservatively with antibiotic therapy and with drainage, if necessary. Interval appendectomy is performed at two months after the primary treatment, all patients also undergo colonoscopy prior to appendectomy. | Procedure: Interval appendectomy<br>* Laparoscopic appendectomy<br>|
| Active Comparator: Follow-up with MRI<br>The periappendicular abscess, diagnosed by a CT-scan or MRI, is initially treated conservatively with antibiotic therapy and with drainage, if necessary. The patients undergo abdominal magnetic resonance imaging at two months after the primary treatment, all patients also undergo colonoscopy right after the MRI. | Procedure: Follow-up with MRI<br>* Abdominal MRI<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Treatment success | Treatment success in both treatment arms. In the interval appendectomy evaluated as possible morbidity related to appendectomy and successful appendectomy and in the follow-up treatment arm as possible recurrence of the appendicitis and/or abscess during a one-year follow-up | One year after the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Possible appendiceal or colon tumours | The incidence of possible tumours | 1-10 years | 
| Possible diagnosis of Crohn's disease | The incidence of possible Crohn's disease | 1-10 years | 
| The length of hospital stay | Length of hospital stay | up to one year | 
| Sick leave | Sick leave (days) | up to one year | 
| Overall morbidity | Complications related to disease / intervention | Up to 10 years, time points 1, 3, 5 and 10 years | 
| Mortality | Mortality | Up to 10 years | 
| Treatment costs | Overall treatment costs | Up to 10 years |