Introduction: Percutaneous iliosacral screws are commonly used for the fixation of the posterior pelvis. The procedure is technically demanding because of the limitations of radiological visualisation of the relevant landmarks. There have been several reports of misplaced screws and other complications, occasionally with serious consequences. To achieve a secure surgical procedure we routinely use a CT-guided technique for percutaneous pelvic screw fixation since 2004.

Methods: Between September 2004 and January 2009, 39 patients were treated using CT-guided screw fixation. Under general anaesthesia patients were placed on a vacuum mattress in a stable lateral position within the CT gantry (Siemens SOMATOM definition; i-Fluoro: 20mAs; Hand CARE mode). The scanner bed was on a calibrated track so the same images could be used and repeated throughout the procedure. Gantry and patient were draped under sterile conditions. The laser sights of the CT indicated the cutaneous site which corresponded to the underlying osseous level (first or second sacral pedicle). At this the CT scan trajectory in the CT-fluoro mode indicated the extrapolated position of the guide-wire. A 3.2mm guide-wire was inserted using battery-powered equipment or hammer blows. When the guide-wire was in a correct position a self-drilling cannulated lag screw was placed (6.5mm DePuy). Two screws were inserted in sacral fractures, one screw in sacroiliac ligament ruptures.

Results: 19 of 39 patients were polytraumatized. In 10 cases there were both side injures. Overall 71 screws were placed. Median time for the procedure was 36 minutes in unilateral lesions and 48 min in bilateral lesions. There were no cases of infection, non-union or neurological deficit. Postoperative CT revealed correct screw positions in all cases. Screw removal was done routinely in the patients younger than sixty years to resolve the blocked sacroiliac joint.

Conclusions: CT-guided is a safe and feasible treatment option in patient with instable pelvic ring lesions. A close collaboration between interventional radiologist and surgeon is essential. Compared to other procedures g.e. internal plate fixation or fluoroscopic guided procedures CT-guided screw insertion seems to be more secure and could strongly be advocated.

Introduction: Bilateral and transverse fractures of the first two sacral vertebrae with intrapelvic intrusion of the lumbo-sacral spine are very rare injuries. In most cases the lesion occurs after a fall from great height in a kyphotic position when landing. Today’s CT-scans in these mostly polytraumatized patients enable a clear diagnosis. In contrast conventional radiographs have a high risk to ignore these fractures. Operative treatment requires proper reduction and secure fixation which so far is not unrestricted possible using recommended techniques. For reduction lumbo-sacral distraction followed by lordotic extension is essential but difficult to obtain. Therefore we modified the lumbo-pelvic instrumentation to facilitate these requirements.

Methods: In the last four years we treated three female patients (aged 27–68 years) as follows: Variable axis screws (VAS – Synthes®) were inserted in the L4 and L5 pedicles and connected with two connecting rods. An additional variable axis screw was inserted in each posterior iliac spine. These both screws were connected with a transverse connecting rod situated over the transverse fracture line. This rod was connected with the two upright rods using a rod-to-rod connector and forming a hinged joint. Due to the not tightened nut of the pedicle screws at that time it was possible to spread the lumbo-sacral fracture line. After tightening of the lumbar screws the upper part of the body was slightly elevated resulting in a lordotic extension in the hinged joint. Subsequently the hinged joint was locked (Video).

Results: Postoperative CT scans revealed anatomic reduction and properly inserted implants in all cases. Follow-up was uneventful but a heparin related thrombopenia in one patient. Two patients were mobilized under full weight bearing within 4 and 10 days, respectively. In one cases this was not possible because of relevant foot fractures. Neurological deficits completely resolved in one patient within fourteen days and markedly diminished in another patient within months (persistent neuralgia). In one patient no neurological deficit existed. In all cases a complete hardware removal was done in 8 to 11 months.

Conclusions: The presented procedure is suitable for the so-called jumper’s fractures and results in anatomic reduction of the displaced fractures and a secure stabilization. The described hinged joint offers effective lordotic extension which is the key point for reduction. Thus this configuration is a reduction as well a fixation device. Full weight bearing in an erect posture is immediately possible and clearly shorten the rehabilitation period.