How to Identify Tunneling Wounds: Clinical Assessment Guide
How to tell if a wound is tunneling?
The Quick Answer
**Probe the wound edges** with a sterile cotton-tipped applicator—if resistance disappears and the probe advances beyond visible wound depth, tunneling exists. Document using clock-face notation (e.g., '3cm tunnel at 6 o'clock'). Associated signs: persistent drainage from specific edge location, foul odor despite surface cleanliness, delayed healing despite appropriate dressings, or recurrent abscess formation near wound margins.
Why We Ask This
Superficial wound measurements miss hidden tracts, causing clinicians to document 'improving' wounds while infection progresses undetected in tunnels—resulting in sudden deterioration or systemic infection when tracts rupture or seed bacteremia.
The Practical Science
Systematic probing technique: insert sterile probe gently at wound edge, advance until resistance met (healthy tissue) or sudden loss of resistance (tunnel). Never force probes—false passages cause tissue damage. Measure depth in centimeters and direction using clock-face system relative to patient's body position for consistent tracking.
In Clinical Practice
A diabetic foot ulcer measuring 2cm×2cm superficially shows no improvement after 3 weeks of standard care. Probing reveals 4cm tunnel extending plantarward—prompting switch to iodoform gauze packing and culture-directed antibiotics. Within 10 days, tunnel depth reduces to 1cm with granulation tissue visible at base.
References & Context
Tunneling vs. Undermining Wound | Definition & Overview - Lesson"There are a few symptoms that can alert a health care professional to tunneling and undermining. These symptoms include fever because of infection in the wound, pain in and around the wound, malodorous (bad-smelling) discharge from the wound, and skin maceration around the wound."