Osseous and ligamentous injuries of the pelvic ring with rotational and translational instability are rare injuries caused by high-energy trauma. As these injuries usually occur as part of multiple traumas, they are therefore related to increased morbidity and mortality.

Internal fixation has become the method of choice, for definitive treatment of unstable pelvic injury as nonoperative treatment and sole use of external fixation, both have poor radiological and functional outcomes^1,2).

In the management of complex pelvic ring disruptions, stable reduction and rigid fixation of the sacrum and posterior ring structures are of paramount importance. Increased risk for surgical and implant-related morbidity is the major concern with the use of ilio-sacral screws and iliolumbar fixations. This is especially the case in difficult situations, such as bilateral comminuted sacral fractures, and dysmorphic sacral fractures. Various biomechanical studies have reported that posterior transiliac plates provide maximum resistance to distracting forces by the principle of tension band^3,4).

Minimally invasive transiliac plate osteosynthesis represents a relatively simple surgical method with a wide range of indications. Primarily, this method is used in potentially unstable posterior pelvic fractures and in cases of subtle instability such as lateral compression type 1 injuries. Although this fixation provides a better functional outcome, this technique poses a threat of implant loosening and impingement due to the subcutaneous location of the posterior pelvic ring structure. Our modification of transiliac plate fixation offers (a) deeper placement of the plate and (b) almost nullifies chances of implant backout.

1. Step 1: Preoperative Planning

In cases of multiple traumas, definitive surgical treatment with internal fixation is indicated when the patient is adequately resuscitated and all other major injuries have been identified and addressed. The soft tissues surrounding the pelvis should be carefully assessed. Abrasions, lacerations, and degloving injuries must be resolved before internal fixation.

To confirm the diagnosis and identify potential instability, it is important to review all images (X-ray pelvis with both hips anteroposterior, pelvis inlet, outlet view, two- and three-dimensional computed tomography sections) Innocuous looking zone 1, 2, and 3 sacral injuries with extension into the facet joint (Isler type 2 and 3) are often missed or neglected, but are nonetheless important determinants of overall pelvic ring instability.

2. Step 2: Positioning of Patient

Patient positioning and procedural setup are of utmost importance. Routine use of a radiolucent operating table is recommended. The patient is placed into a prone position over a spine frame/bolster, with both arms abducted to 90° and elbow flexed.

Fluoroscopic views (C-arm) views are taken to ensure optimal posteroanterior and the orthogonal pelvic inlet and outlet views. It is to be highlighted that, in the supine and prone position, inlet and outlet view visualization is reversed (i.e., what is visualized as an outlet view in the supine position becomes an inlet view in a prone position and vice versa).

3. Step 3: Skin Incision and Exposure of Posterior Superior Iliac Spine (PSIS) (Fig. 1, 2)

Figure 1. Two curvilinear skin incisions each measuring 2.5 cm over bilateral posterior superior iliac spine.

Figure 2. Exposure of both tables of posterior superior iliac spine.

Two curvilinear skin incisions each measuring 2.5 cm over bilateral PSIS are marked. The C-arm is used to check the position of the incisions.

Marked incisions performed, subcutaneous dissection is performed, the gluteus maximus fascia is incised at its attachment, dissected subperiosteally, and the PSIS inner and outer tables are exposed.

4. Step 4: Formation of Subcutaneous Tunnel (Fig. 3, 4)

Figure 3. Formation of subcutaneous tunnel.

Figure 4. Marking of the osteotomy site.

A long hemostat is introduced beneath the multifidus muscle and a tunnel is formed in an atraumatic manner. With the hemostat as reference, the osteotomy site is marked on either PSIS.

5. Step 5: PSIS Osteotomy and Osteotomized Site Preparation (Fig. 5)

Figure 5. 2 cm×2 cm posterior superior iliac spine osteotomy with oscillating saw.

A 2 cm×2 cm osteotomy is performed with an oscillating saw over each marked PSIS and labeled for each side.

To avoid hitting the spinous process while tunneling the plate, the surgeon should be careful that the osteotomy does not become too deep. However, the osteotomy also should not be too superficial as this may increase the chances of nonunion or resorption of osteotomized bone.

The lateral edge of the osteotomized site is nibbled to ensure optimal seating of the plate on the iliac wing.

6. Step 6: Implant Choice and Plate Contouring (Fig. 6)

Figure 6. Plate contouring.

A 3.5-mm recon plate is chosen to ensure fixation across both sacroiliac (SI) joints. Most commonly, 13-hole, 14-hole, and 16-hole recon plates are used. The length of the plate should be sufficient to allow transfixation of each SI joint by at least two screws on either side.

The plate spans the sacrum between the first and third sacral foramen. As per the fracture configuration, one or two plate(s) may be used.

The plate is contoured in the form of an “M” and tailored to the local anatomy of the region. The metallurgy of the implant plays a vital role in contouring, and is therefore important for the secure fixation of the plate.

7. Step 7: Plate Placement (Fig. 7)

Figure 7. Plate placement in a preformed subcutaneous tunnel.

The contoured plate is passed across the ipsilateral trough created by the osteotomy on the ipsilateral PSIS. It is then slid underneath the paraspinal muscles in the pre-prepared tunnel to span the sacrum and gain fixation on the contralateral ilium.

Two ballpoint pushers are used to hold the seated plate over the osteotomized ilia on the two sides.

8. Step 8: Plate Fixation and Sequence of Screw Tightening (Fig. 8)

Figure 8. Plate fixation and sequence of screw tightening.

The first screw is placed bilaterally in the ilium adjacent to the osteotomized PSIS. The second screw is a long screw placed in an oblique fashion between the inner and outer tables of the ilium in one of two directions. In the first configuration a screw is directed laterally and cranially towards the iliac crest. This screw is usually 60-80 mm in length.

In the second configuration a screw is directed caudally and laterally along the sacral canal. Care is taken to ensure that this screw is always superior to the greater sciatic notch. The length of this screw varies between 90-130 mm. The first screw is slightly loosened by 2-3 turns and the second, long, oblique screw is tightened. This is followed by tightening the first screw. Optimal seating of the plate is ensured by following this sequence.

The third and fourth screws are bilaterally directed medially and caudally to transfix the SI joints. To avoid vascular injury to the internal iliac pedicle or the sacral venous plexus, these screws should never penetrate the ala of the sacrum anteriorly.

9. Step 9: Replacement of Osteotomized PSIS Bony Fragment (Fig. 9)

Figure 9. Repositioning of osteotomized fragment and temporary K-wire fixation.

The osteotomized PSIS segment is replaced over the plate and transfixed temporarily with K-wire. Thereafter, the periosteum is carefully reposed over the osteotomized fragment to ensure fragment vascularity.

This closure must be watertight to ensure that it acts as an internal splint. The K-wire is removed after the closure of periosteum and subcutaneous tissue.

While this modification ensures the osteotomized fragment acts as a local vascularized bone graft, it also adds secondary stability to the fixation. Once healed, the graft almost nullifies the chances of the plate backing out.

10. Step 10: Closure of the Wound (Fig. 10)

Figure 10. Watertight closure of periosteum.

The surgical site is closed in layers.

Following pelvic fracture fixation (Fig. 11), patients were permitted to sit at the bedside starting the day after surgery, with no initial weight-bearing. At 6 weeks and 12 weeks, postoperative clinical and radiographic assessments were conducted for any signs of radiological displacement. Weight-bearing was initiated at 6 weeks for patients with low-grade pelvic injuries. However, for severe injuries, weight-bearing was delayed until 12 weeks. The rehabilitation protocol was customized to the individual based on associated injuries, fracture patterns, and the chosen management approach.

Figure 11. Preoperative (A-C) and postoperative (D-F) radiographs of a patient who underwent surgery by this technique.

Minimally invasive transiliac plating is a promising alternative to iliosacral screw fixation for the stabilization of the posterior pelvic ring. Transiliac plating offers safety and comparable functional outcomes while minimizing risks to neurovascular structures. A recent meta-analysis emphasized the challenge of implant loosening in posterior pelvic ring fixation, particularly with iliosacral screws compared to plating^5-7).

Traditionally, transiliac plating methods have been associated with hardware complications, necessitating additional surgeries for removal, as well as creating emotional and financial burdens on patients. These issues are addressed by our modified technique by ensuring deeper implant placement, mitigating impingement risks, and providing enhanced biomechanical stability near the fracture site and posterior pelvic ring^8,9). The possibility of implant back out is virtually eliminated by achieving union at the osteotomy site and is particularly beneficial for complication-prone osteoporotic patients.

In conclusion, this modification in tension band plating demonstrates potential in reducing both hardware complications and implant backout while providing comfort to the patients as well as the surgeon peace of mind.

No funding to declare.

No potential conflict of interest relevant to this article was reported.