Abscess Aspiration

May 18, 2020 updated by: Robert Ehrman, Wayne State University

Study Protocol for A Randomized Controlled Trial of Incision and Drainage Versus Ultrasound-Guided Needle Aspiration for Uncomplicated Skin Abscesses

Incision and drainage (I&D) is the standard guideline treatment of uncomplicated skin abscesses (a boil or bumo beneath the skin). Ultrasound-guided needle aspiration (USGNA) is a minimally invasive and less painful alternative treatment, but has not been validated as non-inferior to I&D. Multiple studies have shown successful treatment with USGNA of breast, face, neck, and/or trunk abscesses in combination with oral antibiotics with success rates as high as 97%.

In 2011 Gaspari et al. published a landmark article on the use of USGNA for skin abscesses. In this randomized controlled trial, USGNA and I&D had failure rates of 74% and 20% respectively, which makes USGNA an unappealing treatment option. However, the study had several methodological issues that likely biased the results in favor of I&D, including the following: 1) aspiration was performed with an 18-gauge needle which is often too small to aspirate thick purulence (or pus); 2) failure to fully aspirate all abscess contents was a priori defined as treatment failure rather than strictly clinical outcomes; 3) the abscess aspiration procedure was not standardized; and 4) post-intervention oral antibiotic therapy was not used on all patients.

The main hypothesis is that a modified protocol of the Gaspari et al. USGNA study to address these flaws will demonstrate a failure of USGNA comparable to I&D for the treatment of uncomplicated skin abscesses. First, the study will standardize the use of larger 14-gauge needle on all USGNAs. Second, USGNA intervention failure need not be defined as the inability to completely aspirate all abscess cavity contents under ultrasound guidance. Previous studies have demonstrated clinical success with USGNA of skin abscesses without applying the rigid failure criteria chosen by Gaspari et al. There is only one study in the literature to suggest that there is no correlation between a small quantity of residual abscess contents post-USGNA and ultimate clinical failure, however, there are no studies which specifically address this clinical question. In this study, initial treatment failure of USGNA will be defined as the inability to aspirate any purulent material. Third, treatment outcomes in this study will be determined by clinical resolution of abscess at the study endpoint of 7-10 days, which is a well-established timeline for anticipated abscess healing and endpoint clinical follow-up. Fourth, ultrasound fellowship-trained emergency physicians will perform USGNA in standardized fashion on all enrolled patients. Lastly, post-intervention oral antibiotic with methicillin-resistant Staphylococcus aureus (MRSA) coverage will be provided and compliance closely monitored throughout the study.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Anticipated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Non-toxic patients who present with an uncomplicated, superficial skin abscess of the head/neck, torso, extremities, and buttock will be eligible for inclusion.
  2. Abscesses must be verified by physical examination and bedside ultrasound.
  3. Patients with clinical history of diabetes mellitus and previous diagnosis of MRSA will be included.

Exclusion Criteria:

  1. Patients will be excluded if age less than age 18 or pregnant.
  2. Patient or legal guardian is unable to give consent.
  3. Patients with no means of clinical follow-up will be excluded.
  4. Complicated abscesses, defined as an abscess with associated sepsis, lymphangitis, or osteomyelitis, requiring intravenous antibiotic therapy, requiring hospital admission, previous surgical drainage at site of abscess, overlying skin lesion/fistula/ulceration with the exception of cellulitis, perforated or actively draining abscess, duration of symptoms > 5 days,1,28 and/or multiple concurrent abscesses that can be clinically regarded as chronic in nature will be excluded.

4) Abscess locations which will be excluded are dental, peritonsillar, anorectal, genital/inguinal, axillary if suspicion for chronic hidradenitis suppurativa, or pilonidal/intragluteal at the base of the coccyx.

5) Abscesses greater in size than 3x3x3 cm in any dimension will be excluded. [It has been suggested extensively in the surgical literature that an abscess diameter >3 cm should have surgical/catheter-drainage as the initial management instead of needle aspiration]2,5,15,19,27,33 [It has been reported that abscesses >3 cm in size have increased failure rates]15 6) Abscess depth is greater than maximal needle length. 7) Patients with immunosuppression from following clinical conditions will be excluded: HIV, cancer on active chemotherapy.

8) Patients with active history of IV drug use will be excluded.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Surgical I&D Procedure
The abscess cavity will be evaluated thoroughly with ultrasonography. The site will be prepared and draped. The skin surface will be infiltrated with local anesthetic with a 25-gauge needle. The treating clinician may provide ultrasound-guided regional anesthesia for procedural analgesia at their discretion. Incision of the skin surface with a number 11-blade scalpel will be performed over the largest area of infection; the incision will be extended into the abscess cavity. A blunt instrument will then be used to break up internal loculations if present. Repeated instrumentation through the initial incision or extension of the original incision will be performed if needed. Lastly, iodoform packing will be inserted through the incision into the cavity. The decision to send the abscess contents for microbiological culture and susceptibility analysis will be at the discretion of the treating clinician.
Procedure: Incision and Drainage (I&D)
The current standard procedure to drain an abscess of purulent material.
Experimental: Ultrasound-guided Needle Aspiration Procedure
The abscess cavity will be evaluated thoroughly with US. The site will be prepared and draped. The skin surface and anticipated needle track will be infiltrated with local anesthetic with a 25g needle. The treating clinician may provide ultrasound-guided regional anesthesia for procedural analgesia at their discretion. Under direct US-guided visualization, a 14g 2in steel needle attached to a 40mL syringe will be advanced into the abscess cavity with manual negative pressure. The needle tract will be extended obliquely 2-3 cm between the skin and abscess to prevent fistulization. Purulent material will be aspirated until no further purulence can be aspirated. Multiple aspiration attempts on the initial visit will be permitted to maximally drain the abscess cavity. Additionally, irrigation of the abscess cavity with sterile saline will be permitted to break up internal loculations if present, as has reported previously for trunk and breast abscesses.
Procedure: Ultrasound-guided Needle Aspiration Procedure
The intervention under investigation utilizes an ultrasound-guided needle to less invasively drain an abscess.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Abscess cure or treatment failure
Time Frame: 7-10 days
Treatment cure will be defined by the complete resolution of the abscess based on clinical signs and symptoms (no or minimal tenderness, erythema, fever, wound drainage, warmth, fluctuance, or induration) at the 7- to 10-day follow-up. Treatment failure will be defined by: fever (attributable to the infection), persistent or increased size >25% of the original abscess, requiring conversion to I&D (USGNA intervention group) or repeat I&D (I&D intervention group), requiring additional antibiotics, or requiring hospital admission within 7-10 days after treatment. Participants who either withdraw from the trial or are lost to follow-up before a determination of final outcome will be classified as treatment failure.
7-10 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient Satisfaction
Time Frame: Baseline (Day 1)
Patient satisfaction with each procedural intervention will be assessed, with the hypothesis that USGNA will have higher overall satisfaction rates than I&D.
Baseline (Day 1)
Patient Comfort Level
Time Frame: Baseline (Day 1)
Patient comfort for each procedural intervention will be assessed , with the hypothesis that USGNA will have lower overall pain scores compared to I&D.
Baseline (Day 1)
Abscess Characteristics and Correlation with Treatment Failure
Time Frame: Baseline (Day 1)
Assessment of whether specific abscess characteristics have any correlation to procedural failure in either intervention group.
Baseline (Day 1)
Abscess Reoccurrence
Time Frame: Day 21-30
The cumulative rate of abscess recurrence will be assessed at the 21- to 30-day follow-up.
Day 21-30
Abscess Site infection
Time Frame: Day 21-30
Infections involving the same site at the 21- to 30-day follow-up will be considered a recurrent infection.
Day 21-30

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Wayne State University

Investigators

  • Principal Investigator: Robert Ehrman, MD, Wayne State University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

June 1, 2020

Primary Completion (Anticipated)

December 31, 2020

Study Completion (Anticipated)

December 31, 2020

Study Registration Dates

First Submitted

October 10, 2019

First Submitted That Met QC Criteria

October 11, 2019

First Posted (Actual)

October 15, 2019

Study Record Updates

Last Update Posted (Actual)

May 19, 2020

Last Update Submitted That Met QC Criteria

May 18, 2020

Last Verified

May 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1804001385

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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