General Surgery: Asepsis, Wounds, Biopsy and Neck Pathology
General Surgery
This domain tests surgical principles applied to the head and neck: sterilisation, wound healing, suture choice, biopsy technique, fluid and shock management, and salivary gland and neck swellings.
Core rules
- Autoclave sterilisation at 121 °C, 15 psi for 15 minutes; chemical indicators and biological spore testing verify function. Disinfection removes pathogens; sterilisation removes all microorganisms including spores.
- Wound healing: primary intention in clean apposed wounds, secondary intention in infected or gaping wounds with granulation, tertiary intention when closure is delayed.
- Sutures: catgut and polyglactin are absorbable; silk and nylon are non-absorbable. Skin sutures of the face are usually removed at 5 days, scalp at 7–10 days.
- Biopsy: incisional for large or suspected malignant lesions, excisional for small discrete lesions; never biopsy a suspected melanoma piecemeal, and always send tissue in formalin with orientation.
- Salivary tumours: pleomorphic adenoma is the commonest, arises in the parotid, and requires excision with a margin because of pseudopodia and recurrence risk; mucoepidermoid carcinoma is the commonest malignant salivary tumour and is graded by MEC components.
- Burns: rule of nines for extent, Parkland formula (4 mL × body weight in kg × % burn) for initial 24-hour crystalloid, half in the first 8 hours.
Worked example
A 20% total body surface area burn in a 70 kg patient: 4 × 70 × 20 = 5,600 mL in 24 hours, given as 2,800 mL in the first 8 hours (about 350 mL/hour) and the remaining 2,800 mL over 16 hours. The reasoning chain is: extent from the rule of nines, volume from Parkland, then the half-in-eight rule which reflects the early capillary leak - timing, not just total volume, is what the examiner is testing.
Traps
- Calling disinfection sterilisation.
- Using an incisional biopsy for a small localised lesion that could be excised whole.
- Administering the whole Parkland volume rapidly rather than half in eight hours.
- Ignoring the facial nerve when planning parotid surgery.