Symphysis Pubis Plating (Anterior Pelvic Ring ORIF)

Indication. Open reduction and anterior plating of the pubic symphysis is performed for a disrupted symphyseal joint that is part of an unstable pelvic ring — the classic open-book (anteroposterior compression, APC) injury. The operation restores the anterior pelvic ring, but only as one half of a ring that must be stable at the back as well. Absolute indications

• Symphyseal diastasis greater than 2.5 cm on the AP pelvis with clinical or radiographic pelvic ring instability (open-book / APC-II or APC-III pattern).
• Combined anterior and posterior pelvic ring injury requiring anterior stabilisation to restore ring continuity.
• Open pelvic injury with symphyseal disruption needing debridement and stabilisation.
• Associated bladder or urethral injury requiring simultaneous repair and symphyseal stabilisation. Relative indications
• Diastasis of 1.5–2.5 cm with persistent pain or instability after non-operative management with a pelvic binder.
• A young patient with high functional demand and residual symphyseal pain after conservative treatment.
• A polytrauma patient in whom early mobilisation is critical and anterior plating facilitates nursing and respiratory care. Contraindications. Absolute: haemodynamic instability requiring damage-control external fixation only (convert later); active pelvic or abdominal infection; severe osteoporosis or bone loss precluding stable screw purchase. Relative: a patient too unstable for prolonged positioning; pregnancy in the second or third trimester (consider external fixation until delivery); a pre-existing severe abdominal wall hernia or a heavily scarred prior Pfannenstiel incision. The one principle that governs everything. Whatever you do at the front of the ring, isolated anterior plating fails when the back of the ring is unstable. Implant failure runs 5–15 percent when posterior ring instability is not addressed and drops below 5 percent with concurrent posterior stabilisation. So confirm and plan the posterior ring (percutaneous SI screws preferred) before or during the same sitting as the anterior plate. Consent specifically for bleeding from the corona mortis or obturator vessels, bladder or urethral injury, infection (3–8 percent), heterotopic ossification (10–25 percent), chronic symphyseal pain or non-union (5–10 percent), and the possibility of staged posterior fixation and a second anaesthetic. Setup. Supine on a radiolucent table, both arms abducted or tucked, with a small sacral bump to improve access to the symphysis; the table must allow full inlet, outlet and Judet views from both sides. General endotracheal anaesthesia with muscle relaxation. Wide skin prep from xiphisternum to mid-thigh including the perineum. Insert a Foley catheter before incision and confirm bladder decompression; have a vascular set, blood products and cell salvage available.

The goal is to expose the symphysis through a Pfannenstiel approach, protect the bladder and the corona mortis, reduce the diastasis anatomically, and stabilise the anterior ring with a contoured reconstruction plate — always in the context of a posterior ring that is stable or simultaneously fixed. The exposure (Steps 2–4) is the heart of the operation.

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The six structures that can hurt you during this approach, and how to protect each:

Rehabilitation. Weight-bearing is dictated by posterior ring stability, not the anterior plate alone. | Phase | Timing | Weight-bearing & immobilisation | Therapy & milestones | |-------|--------|---------------------------------|----------------------| | Immediate | Day 0–7 | Bed to chair on day 1; touch-down weight-bearing on the affected side if a unilateral injury, or weight-bearing as tolerated if the posterior ring is stable | LMWH for DVT prophylaxis from day 1; Foley for 48–72 h; drains out at 48 h; multimodal analgesia | | Early | Week 1–6 | Touch-down or partial weight-bearing (20 kg) for 6 weeks if the posterior ring was unstable; avoid hip flexion beyond 90 degrees and adduction | Isometric quads and gluteals from day 1; gentle hip ROM from week 2; core and pelvic floor from week 4 | | Late | Week 6–12+ | Progress to full weight-bearing at 6–12 weeks once radiographs confirm stability | Low-impact activity at 3 months; running and sport at 6 months if united and pain-free | Most patients return to desk work by about 6 weeks and to heavy manual work by 12–16 weeks. Review AP, inlet and outlet radiographs at 2, 6 and 12 weeks. Hardware is removed only at 12–18 months if symptomatic (plate prominence or pain) — it is not routine. Complications

Relevant surgical anatomy - Pubic symphysis — a fibrocartilaginous joint between the medial ends of the pubic bones, stabilised by the superior and inferior pubic ligaments and the anterior and posterior ligaments; the 3–5 mm symphyseal disc is not violated during plating, and the pubic tubercles are the key landmarks for rectus insertion and plate placement.

• Corona mortis — an anomalous vascular anastomosis present in 20–30 percent of patients (up to 34 percent in anatomic series), arising from the inferior epigastric or external iliac artery and crossing the superior pubic ramus 5–7 cm lateral to the symphysis to drain into the obturator or external iliac vein; mean calibre about 2.5 mm.
• Space of Retzius — the extraperitoneal space between the pubic symphysis and the bladder, developed between rectus abdominis and transversalis fascia; the bladder lies immediately posterior and must be decompressed and protected.
• Rectus abdominis insertion — onto the superior pubic tubercle and the anterior pubic body; elevated sharply for exposure and reattached at closure to prevent hernia and maintain core stability.
• Spermatic cord / round ligament — cross the inguinal canal just lateral to the pubic tubercle and are protected by lateral retraction.
• Obturator nerve and vessels — exit the pelvis through the obturator canal 2–3 cm lateral to the symphysis; at risk during lateral superior ramus dissection and screw placement. Classification. The Young-Burgess anteroposterior compression (APC) grades describe how far the ring has opened and how unstable it is, and they map directly onto the operative decision:

In the Tile system these map to Tile B1 (open-book, rotationally unstable) for APC-II and Tile C (vertically unstable) for APC-III. Key evidence. Anterior symphyseal plating restores greater than 80 percent of native pelvic ring stiffness when the posterior ring is stable or simultaneously fixed. A single superior plate with three screws on each side is adequate for APC-II injuries, while double plating (superior plus anterior) is reserved for APC-III or osteoporotic bone. Implant failure runs 5–15 percent when posterior ring instability is not addressed and falls below 5 percent with concurrent posterior stabilisation — isolated anterior plating in the presence of a posterior ring injury leads to early plate breakage or screw loosening in up to 30 percent. Simultaneous or staged posterior fixation (percutaneous SI screws preferred) is the standard of care for APC-III and combined injuries. Anatomic series report the corona mortis in 20–40 percent of specimens, making its routine identification and ligation the single most important step in preventing life-threatening anterior pelvic bleeding.