Summary

Ingrown Toenail (Onychocryptosis) is an extremely common, painful condition where the lateral or medial edge of the nail plate pierces the adjacent nail fold, acting as a foreign body. This triggers a cascade of inflammation, infection (Staph aureus), and eventually the formation of hypervascular Granulation Tissue. While often trivialized, it causes significant morbidity and time off work. Eponymous surgical cures abound, but the evidence is clear: Partial Nail Avulsion with Phenol Ablation (Chemical Matrixectomy) is the Gold Standard, reducing recurrence rates from 70% (simple excision) to <5%. [1,2,3]

Key Facts

• The Spicule: The problem is rarely the "whole nail". It is usually a sharp spike (spicule) of nail hidden deep in the fold, left behind by improper trimming ("bathroom surgery").
• Antibiotics don't work alone: You cannot kill an infection caused by a foreign body (the nail) without removing the foreign body. Antibiotics are an adjunct, not a cure.
• Phenolisation: Applying 80% Phenol to the germinal matrix kills the nail-growing cells in the corner so the nail grows back narrower. This is the difference between a temporary fix and a permanent cure.

Clinical Pearls

"Cut it straight": The #1 cause is cutting the corners of the nail curved. This leaves a hidden spicule that grows out into the flesh. Always cut toenails straight across.

"The Granuloma": That red, bleeding lump of flesh is not cancer (usually). It is "proud flesh" (granulation tissue) trying to heal the wound. It bleeds if you look at it. Silver Nitrate shrinks it.

"Probe the Bone": In a diabetic with a chronic ingrown nail, always probe the wound. If you hit hard bone, they have Osteomyelitis.

                 PAINFUL TOE
                      ↓
               STAGE OF DISEASE?
            ┌─────────┴─────────┐
         STAGE 1             STAGE 2/3
     (Inflammation)         (Pus/Granulation)
            ↓                   ↓
      CONSERVATIVE           SURGICAL
    (Soak/Cotton wisp)    (Wedge Resection)
            ↓                   ↓
         FAILED?           USE PHENOL?
            ↓             ┌─────┴─────┐
        SURGERY          YES         NO
                      (Standard)  (Diabetic/Vascular)

Indications

• Stage 1 only.
• Patient refuses surgery.

Protocol

• Slant Back: Filing the corner of the nail to remove the pressure point (by a podiatrist).
• Cotton Wisp: Packing a tiny piece of cotton wool under the nail corner to lift it away from the skin.
• Soaks: Warm salt water (draws out infection).
• Antibiotics: Only if cellulitis extends proximally (Flucloxacillin/Cephalexin).

1. Wedge Resection (Partial Nail Avulsion)

• Standard of Care.
• Steps:
  1. Digital Block (Lignocaine).
  2. Tourniquet (Toe).
  3. Split the nail plate longitudinally (lateral 2-3mm).
  4. Avulse the strip of nail with the spicule.
  5. Phenolisation: Apply 80% Phenol to the matrix for 3 minutes. Wash with Alcohol.
• Outcome: 95-98% Cure.

2. Winograd Procedure

• Indication: If there is a massive granuloma or deep infection where the fold needs to be excised.
• Technique: Excising a wedge of skin/soft tissue along with the nail and matrix. Sutures used.
• Con: More pain than Phenol alone.

3. Zadik Procedure (Total Matrixectomy)

• Indication: Recurrent failure or Pincer nail.
• Technique: Removal of the entire nail plate and ablation of the entire germinal matrix.
• Outcome: No nail grows ever again.

Phenol Efficacy

• Cochrane Review: Confirmed that surgical interventions are more effective than non-surgical treatments, and that the addition of Phenol significantly reduces recurrence compared to excisional surgery alone.

Antibiotics

• Reyzelman et al: Randomized trial showing that oral antibiotics did not improve healing times or reduce pain in patients undergoing nail avulsion. The surgery is the antibiotic.

The Problem

Your nail is growing into your skin like a shovel digging into the dirt. It cuts the skin, letting germs in.

The Fix

We perform a "Partial Nail Avulsion".

1. Numb the toe.
2. Remove just the thin strip of nail that is digging in (not the whole nail).
3. Put a chemical (Phenol) on the root so that specific edge never grows back.
4. Your nail will look normal, just slightly narrower.

Q1: What are the borders of the Germinal Matrix? A: It extends approximately 5mm proximal to the eponychium (cuticle) and laterally to the lateral condyles of the phalanx. Failure to ablate this deep/proximal horn leads to recurrence (regrowth of spicule).

Q2: What is the mechanism of action of Phenol? A: It causes coagulation necrosis of the germinal matrix epithelium, preventing keratinocyte production. Alcohol is used to wash it out (dilution) to stop the burn.

Q3: Name a contraindication to Phenol use. A: Severe Vascular Insufficiency. The chemical burn creates a wound that requires good blood supply to heal. In ischemic limbs, simple avulsion (without phenol) is safer, accepting the higher recurrence risk.

Q4: What is "Onychogryphosis"? A: "Ram's Horn Nail". Hypertrophy and curvature of the nail plate, common in elderly/neglect. Treated with total nail avulsion.

(End of Topic)