A 52-year-old man underwent elective hernia repair under general anaesthesia. Intraoperatively, the surgeon ligated the femoral artery instead of the femoral vein during dissection. The patient developed acute limb ischaemia postoperatively. The patient's legal counsel seeks to establish breach of duty and causation. Which investigation is most appropriate to objectively document the standard of care deviation and establish negligence?

Explanation

## Establishing Professional Negligence in Surgical Injury ### The Legal Framework **Key Point:** Professional negligence in medicine requires proof of three elements: (1) duty of care, (2) breach of that duty, and (3) causation and damage. In surgical cases, breach is established by demonstrating deviation from the standard of care expected of a reasonably competent surgeon in similar circumstances. ### Why Expert Opinion is the Investigation of Choice **High-Yield:** In medical negligence cases, the **standard of care is a legal and professional standard**, not a purely clinical finding. It cannot be determined by imaging or pathology alone. An expert witness (typically a senior surgeon with relevant subspecialty experience) reviews: - The operative notes and surgical technique - Standard textbooks and surgical protocols (e.g., anatomical landmarks, dissection planes) - Current best practice guidelines - Whether a reasonably competent surgeon would have made the same error **Clinical Pearl:** Ligation of the femoral artery instead of the femoral vein is a clear anatomical error — the femoral vein lies medial to the artery. An expert can testify that this violates basic surgical anatomy and standard dissection technique, establishing breach of duty objectively. ### Why This Differs from Diagnostic Investigations | Investigation | Role | Limitation in Negligence | |---|---|---| | **Expert opinion** | Establishes standard of care and breach | **Gold standard for negligence** | | Doppler ultrasound | Documents current vascular injury | Shows damage, not deviation from standard | | Angiography | Confirms arterial occlusion | Shows outcome, not negligence | | Histopathology | Identifies vessel type microscopically | Unnecessary; anatomy is clear clinically | **Key Point:** Imaging and pathology document the *injury* and its consequences, but they do not establish whether the surgeon's action fell below the accepted standard. Only an expert in surgical practice can make that determination. ### Causation Once breach is established (via expert opinion), causation is straightforward: ligation of the femoral artery directly caused acute limb ischaemia, which is a foreseeable and direct consequence. **Mnemonic:** **BREACH** — **B**est expert review, **R**eview of protocols, **E**stablish standard, **A**ssess deviation, **C**ausation follows, **H**old liable.