The present study was carried out from January 2018 to January 2020. A total of 27 patients with unstable pelvic ring fracture underwent both minimal invasive pedicle screw-rod fixation and anterior external fixation in our local department. The inclusion criteria were an age of >18 years old, hemodynamic stability that support patients tolerating surgery well. Patients with soft tissue defects, open fractures were excluded.
Every case was supervised by ECG monitoring. Vessel ultrasound was routinely performed to screen for vascular injury or venous thrombosis. For patients over 60 years old, echocardiography was used to evaluate heart function. Anteroposterior, inlet and outlet pelvic radiographs were taken in all patients. Computed-tomography (CT) scan was further evaluated displaced fracture.
The prone position was employed. The posterior superior iliac spine (PSIS) was marked. Bilateral 6 cm incisions were used 0.5 cm medially along the PSIS. Cortical bone was removed on the osseous entry point. The purpose was to prevent screw cap from soft tissue compression. The bone corridor was established toward the greater trochanter of femur by pedicle finder. The corridor was checked that we did not penetrate the ilium. Pedicle screws were maneuvered into the bilateral dorsal iliac crests. The pedicle screw with diameter of 6.5 mm and length of 65 mm was inserted. A titanium rod with 6 mm diameter was applied to connect the two screws. After adjusting the rod to the right place, the caps of pedicle screws were tightened. The screw positions and reduction was examined by fluoroscopy inlet and outlet views. A typical patient was showed in Fig 1. In case of vertical unstable fracture, patients were added lumbar fixation. The iliac screw was linked with lumbar pedicle screw (Fig 2). After being placed in supine position, the patient was managed by anterior pelvic external fixation. A 1cm incision was made below the anterior superior spine. Soft tissue was dissected to expose iliac crest. Two pins were inserted on each side of the pelvis. Before connected to the external fixation, pins were under fluoroscopic control.
The postoperative rehabilitation
All patients were managed to start functional exercises of lower limbs without bearing from postoperative day 1. After acute pain period, patients were encouraged to take active and positive joint exercises. After 3 weeks, sitting was permitted by the patients. The anterior pelvic external fixation was removed 4 weeks after operations. The crutch-assisted walking was performed by the patients at 6 weeks postoperatively. Patients were allowed to gradually walking with full weight bearing when postoperative imaging demonstrated bone union. Follow-up were ordered at 4 weeks, 8 weeks, 12 weeks, 16 weeks, 24 weeks, 9 months, 12 months, 15 months, 18 months postoperatively.
The radiological findings of pelvic ring were assessed by Matta criteria which measure maximal displacement by anteroposterior, inlet and outlet radiographs: excellent (<4mm), good (5-10mm), fair (11-20mm), poor (>20mm) . The quality of clinical function was evaluated by Majeed criteria which include pain, sitting, standing, sexual intercourse and work. The overall score was 100. The full score was 80 while no score was obtained for work because of patients without work before operation .