Incision and Drainage (I&D)

Overview

Indications

• Fluctuant abscess with a palpable pocket of purulence
• Abscess that has "pointed" (localized to a single area)
• Failed conservative management (e.g., warm compresses)
• Significant pain or expanding cellulitis around the abscess
• Hordeolum, Bartholin gland abscess, pilonidal abscess, perianal abscess

Contraindications / When to Refer

• Pulsatile mass at the site — suggests vascular etiology; do not incise
• Proximity to major vessels or nerves (e.g., femoral triangle, neck)
• Large, deep abscesses requiring OR drainage under general anesthesia
• Foreign body suspected at the site
• Hand infections near tendon sheaths — hand surgery referral
• Periorbital/orbital abscesses — ophthalmology referral
• Dental abscesses involving deep fascial spaces — ENT/oral surgery

Equipment

• No. 11 scalpel blade (preferred) or No. 15
• 1% or 2% lidocaine with epinephrine (1:100,000)
• 25–27 gauge needle for anesthesia
• Curved hemostat (Kelly clamp)
• Culture swab
• Irrigation syringe (20–35 mL) with saline or tap water
• Iodoform or plain gauze packing strip
• Sterile drape, gloves, mask, eye protection

Anesthesia

• Inject 1–2% lidocaine with epinephrine into the dome of the abscess, holding the needle parallel to the skin surface — blanching confirms spread
• For very large or deep abscesses, field block of the surrounding tissue improves anesthesia (anesthesia is harder to achieve in inflamed/acidic tissue)
• Consider procedural sedation for children or very painful abscesses

Step-by-Step Technique

Key Technical Points

• Linear incision is preferred. Avoid cruciate (X-shaped) incisions — the flap tips can necrose, leaving a poor scar.
• A "stab" incision alone is typically inadequate — the incision must span the full length of the cavity for adequate drainage.
• The scalpel is used only to incise the skin; do not use it deep within the cavity.
• In cosmetically sensitive areas (face) or under high skin tension, a stab incision or needle aspiration may be attempted first, with reassessment in 24–48 hours.
• Conform the incision to skin creases or natural folds whenever possible.

Packing: Current Evidence

• Packing has not been proven to significantly improve outcomes over non-packing in most simple abscesses
• Some emergency physicians still pack larger cavities to prevent premature closure and allow continued drainage
• Follow-up in 1–3 days is essential regardless

Adjunct Antibiotics

• MRSA (particularly community-acquired MRSA) is now the predominant organism in cutaneous abscesses
• Antibiotics are generally not required for simple, uncomplicated abscesses after successful I&D in immunocompetent patients
• Antibiotics are indicated for:
  • Surrounding cellulitis > 2 cm from the abscess margin
  • Systemic signs (fever, lymphangitis)
  • Immunocompromised state
  • Failure to respond to I&D alone
  • Preferred agents: TMP-SMX or doxycycline (covers CA-MRSA)

Special Locations

Aftercare / Patient Instructions

• Remove/change packing at 24–48 hour follow-up
• Wound heals by secondary intention
• Warm soaks 2–3×/day after packing is removed
• Return immediately for worsening erythema, fever, or new fluctuance
• Recurrence of abscess in the same location should raise suspicion for: foreign body, underlying osteomyelitis, Crohn's disease (perianal), or hidradenitis suppurativa (axilla/groin)

Intercostal Drainage (Tube Thoracostomy / Chest Drain Insertion)

Indications

Anatomy: The Triangle of Safety

• Anterior border: Lateral edge of pectoralis major
• Posterior border: Anterior border of latissimus dorsi
• Inferior border: Horizontal line at the level of the nipple (5th intercostal space)
• Apex: Below the axilla

Critical rule: Always enter the pleural space over the superior border of the lower rib — the neurovascular bundle (intercostal artery, vein, nerve) runs in the groove on the undersurface of the upper rib.

Equipment

• Chest drain tube (28–32 Fr for fluid; 20–28 Fr for air; 14 Fr pigtail for simple pneumothorax)
• Scalpel with No. 15 blade
• Kelly clamp (curved hemostat)
• 1% lidocaine (plain) + 10 mL syringe + 21 and 25 gauge needles
• Chlorhexidine or povidone-iodine for skin prep
• Sterile drapes, gloves, gown, mask, eye protection
• Underwater seal drainage system (Bülau drain) or dry suction system
• Heavy non-absorbable suture (0 or 1-0 silk/prolene)
• Vaseline gauze-free sterile dressing

Patient Positioning

• Supine with ipsilateral arm raised above the head (abducted and externally rotated) to open up the intercostal spaces
• Head of bed elevated 30–45°
• Identify and mark the insertion site

Step-by-Step Procedure (Open / Blunt Dissection Technique)

Step 1 — Consent, Monitoring, and Analgesia

• Explain procedure and obtain informed consent
• Attach SpO₂ monitor and IV access; consider IV analgesia/sedation (opioid ± benzodiazepine)
• Pre-oxygenate if needed

Step 2 — Positioning and Skin Prep

• Position the patient as above, arm raised
• Clean the skin with chlorhexidine in wide circles; allow to dry
• Apply sterile drapes, exposing only the insertion site

Step 3 — Local Anaesthesia

• Raise a skin wheal with 1% lidocaine using a 25 G needle
• Switch to 21 G needle; infiltrate subcutaneous tissue, periosteum of the rib, and the intercostal muscles
• Walk the needle just over the top of the lower rib as you advance
• Aspirate as you advance — a rush of air or fluid confirms entry into the pleural space
• Inject lidocaine into the parietal pleura (most painful layer)
• Allow adequate time for analgesia to take effect (2–3 minutes)

Step 4 — Skin Incision

• Make a 2–3 cm transverse incision at the selected intercostal space (4th/5th ICS, mid-axillary line)
• Incision should be at least as wide as the tube diameter
• Optionally, make the skin incision one intercostal space below the intended pleural entry point to create a subcutaneous tunnel

Step 5 — Blunt Dissection and Pleural Entry

• Using a Kelly clamp, dissect bluntly through subcutaneous fat and intercostal muscles in a controlled, spreading motion
• Direct the clamp over the top of the rib to avoid the neurovascular bundle
• Apply firm, controlled pressure to pop through the parietal pleura — a rush of air or fluid confirms entry
• Spread the clamp to widen the opening before tube insertion
• Digital sweep: Insert a gloved finger into the pleural space to:
  • Confirm pleural entry (not intra-parenchymal)
  • Clear any clots or adhesions
  • Palpate the lung to ensure it is not adherent

Step 6 — Tube Insertion

• Clamp the distal end of the tube with another Kelly clamp
• Using a clamp on the proximal end, guide the tube into the pleural space
• For pneumothorax: Direct tube apically (anterosuperiorly)
• For fluid (effusion/hemothorax): Direct tube basally and posteriorly
• Advance until all drainage holes are within the thorax
• Typical depth: 8–12 cm from the skin surface (mark at insertion)
• Confirm position: fogging of tube on respiration, drainage of fluid or air

Step 7 — Connect to Drainage System

• Connect tube to the underwater seal drain (Bülau bottle)
• Keep the bottle erect, ~100 cm below chest level
• Check for swinging of the fluid column with respiration (confirms patency)
• Check for bubbling (confirms air leak/pneumothorax drainage)
• Apply suction: −20 cm H₂O for standard drainage; −5 cm H₂O for fluid-only drainage

Step 8 — Secure the Tube

• Secure with a heavy non-absorbable suture (0-silk) anchored to the skin
• Place a mattress or purse-string suture around the wound for closure when the tube is removed
• Apply sterile occlusive dressing (no Vaseline gauze — increases infection risk)

Step 9 — Post-Procedure

• Chest X-ray immediately to confirm:
  • Correct tube position (all drainage holes in pleural space — the radiopaque stripe should be unbroken)
  • Resolution of pneumothorax or drainage of effusion
• Document drainage output (volume, color, character) at regular intervals

Tube Removal Criteria

Seldinger (Pigtail Catheter) Technique — Alternative

1. Anesthetize and confirm pleural entry with needle aspiration
2. Thread a guidewire through the needle into the pleural space
3. Remove needle; dilate track with serial dilators
4. Thread pigtail catheter over guidewire
5. Remove guidewire; connect to drainage system

Complications