A 58-year-old woman undergoes low anterior resection with total mesorectal excision for a mid-rectal adenocarcinoma. Intraoperatively, the surgeon notes that the tumour is adherent to the left ureter. The ureter is carefully dissected free, but a small full-thickness defect is created during mobilization. Which of the following is the most appropriate immediate management of this iatrogenic ureteric injury?

Explanation

## Management of Intraoperative Ureteric Injury ### Clinical Context A small full-thickness ureteric defect is identified intraoperatively during low anterior resection for mid-rectal cancer. The key descriptors are: **small defect**, **intraoperative recognition**, and **mid-ureteric location** (pelvic ureter, middle third). Immediate primary repair is mandatory to prevent stricture, loss of renal function, and sepsis. ### Principles of Ureteric Injury Repair **Key Point:** The management of ureteric injury depends on: - **Timing of diagnosis** (intraoperative vs. delayed) - **Location of injury** (upper, middle, or lower third) - **Type and extent of injury** (small laceration vs. large defect/avulsion) - **Ability to achieve a tension-free anastomosis** **High-Yield:** Intraoperative recognition of a **small** full-thickness ureteric injury allows primary repair (ureteroureterostomy over a double-J stent), which has >90–95% success when performed without tension. Ureteroneocystostomy is reserved for injuries of the **lower third** or when primary anastomosis cannot be achieved tension-free. ### Surgical Repair Options by Ureteric Segment | Injury Location | Repair Method | Indications | |---|---|---| | **Upper/Middle third** | Ureteroureterostomy (end-to-end) | Small defect, minimal tissue loss, tension-free anastomosis achievable | | **Lower third (pelvic ureter near bladder)** | Ureteroneocystostomy ± psoas hitch | Standard for distal injuries; psoas hitch gains 4–5 cm | | **Large defect, any level** | Boari flap, ileal interposition, or autotransplantation | Extensive tissue loss | | **Transureteroureterostomy** | Crossing midline to contralateral ureter | Rare; bilateral injuries, failed prior repairs | ### Why Ureteroureterostomy Over a Double-J Stent is Optimal Here 1. **Small defect:** The stem explicitly states a "small full-thickness defect." For small lacerations with minimal tissue loss, primary end-to-end anastomosis (ureteroureterostomy) over a double-J stent is the **first-line repair** (Campbell-Walsh Urology 12e, Ch 24; Hinman's Atlas of Urologic Surgery). 2. **Location — middle third:** The injury occurs during dissection of a mid-rectal tumour, placing it in the **middle third of the pelvic ureter**. At this level, the ureter retains sufficient mobility for a tension-free end-to-end anastomosis, unlike the very distal ureter where bladder reimplantation is preferred. 3. **Tension-free anastomosis:** The spatulated, stented ureteroureterostomy achieves a watertight, tension-free repair with excellent long-term patency when the defect is small. 4. **Double-J stent:** Stenting for 4–6 weeks protects the anastomosis, maintains luminal patency, and allows healing without stricture. **Clinical Pearl:** Ureteroneocystostomy with psoas hitch is the preferred repair for **distal (lower third)** ureteric injuries or when the defect is too large for primary anastomosis. It is NOT the first choice for a small mid-ureteric defect where end-to-end repair is feasible. **Mnemonic: SMALL MID-URETERIC INJURY = URETEROURETEROSTOMY** - **S**mall defect + **M**iddle third → **U**reteroureterostomy - **D**ouble-J stent → **D**urable patency - **L**ower third or large defect → **U**reteroneocystostomy ± psoas hitch ### Why Other Options Are Suboptimal - **Option B (Transureteroureterostomy):** Reserved for bilateral injuries, failed prior repairs, or when the ipsilateral ureter is too short. Not indicated for a unilateral small defect. - **Option C (Ureteroneocystostomy with psoas hitch):** Appropriate for **lower third** injuries or large defects. Unnecessary for a small mid-ureteric laceration where primary anastomosis is achievable. - **Option D (Observation + percutaneous nephrostomy):** Appropriate only for **delayed** (>72 hours) diagnosis. Intraoperative recognition mandates immediate repair; observation leads to urinoma, sepsis, and renal loss. [cite: Campbell-Walsh Urology 12e Ch 24; Sabiston Textbook of Surgery 21e Ch 51; Hinman's Atlas of Urologic Surgery 3e]