The approach depends on the abscess’s location, size, and accessibility:

1. Before surgery  Evaluation:
   
   • Diagnosis:
     
     • Clinical exam: Localized swelling, redness, warmth, pain, and fluctuance (soft, fluid-filled mass).
     • Ultrasound, CT, or MRI confirms deep abscesses, their size, and surrounding structures.
     • Blood tests assess infection (e.g., elevated WBC, CRP) and comorbidities (e.g., diabetes).
   • IV antibiotics (e.g., amoxicillin-clavulanate, piperacillin-tazobactam) are started for systemic infection or deep abscesses.
   • Blood thinners (e.g., aspirin) may be stopped to reduce bleeding risk.
2. Drainage Techniques:
   
   • Incision and Drainage (I&D):
     
     • For superficial abscesses, performed under local anesthesia (e.g., lidocaine), lasting 15–30 minutes.
     • The skin over the abscess is sterilized, and an incision is made at the most fluctuant point.
     • Pus is drained, and the cavity is irrigated with saline to remove debris.
     • A drain (e.g., Penrose or gauze packing) may be placed to prevent premature closure, removed after 1–3 days.
     • The wound is left open to heal by secondary intention (natural healing from the inside out).
   • Percutaneous Drainage:
     
     • For deep abscesses (e.g., liver, pelvic), performed under sedation or local anesthesia, lasting 30–60 minutes.
     • Ultrasound or CT guidance locates the abscess.
     • A needle is inserted, followed by a guidewire (Seldinger technique), and a catheter (e.g., pigtail catheter, 8–14 Fr) is placed to drain the pus.
     • The catheter is secured and connected to a drainage bag; it remains in place for 3–10 days until output is minimal (<10–20 mL/day).
   • Surgical Drainage (Open Approach):
     
     • For complex or inaccessible abscesses (e.g., brain, deep pelvic), performed under general anesthesia, lasting 1–2 hours.
     • An incision provides direct access (e.g., craniotomy for brain abscess, laparotomy for intra-abdominal).
     • Pus is drained, necrotic tissue is debrided, and the cavity is irrigated.
     • Drains may be placed, and the incision is closed or left open, depending on infection control.
   • Endoscopic Drainage:
     
     • For specific cases (e.g., pancreatic abscess), using endoscopic ultrasound (EUS) to place stents for drainage.
3. After surgery:
   
   • Pus is sent for culture to identify the bacteria and guide antibiotic therapy (continued for 7–14 days).
   • Patients are monitored for 1–3 days (outpatient for superficial, inpatient for deep abscesses).
   • Pain is managed with analgesics (e.g., paracetamol, ibuprofen).
   • Follow-up imaging (e.g., ultrasound) ensures complete drainage for deep abscesses.