Cement augmentation of the navigated iliosacral screw in the treatment of insufficiency fractures of the sacrum. A new method using modified implants

Abstract

Purpose Pelvis ring fractures of geriatric patients are currently a serious problem in orthopedic and trauma surgery. One controversy that remains is the insufficiency fracture of the sacrum with treatment options ranging from conservative to operative. We modified standard 7.3-mm screws with additional perforations at the tip to allow cement injection trough the screw to improve implant anchorage. Method We describe a new method of treatment of sacral insufficiency fractures. We use modified cannulated 7.3-mm screws (Synthes) with additional perforations at the screw tip. This allows the implant augmentation after proper implant positioning and contrast medium instillation for leakage detection. Results All patients (12 female) treated this way, are allowed to weight bear as tolerated immediately after surgery. The pain level (measured by the visual analog scale-VAS) was significantly reduced due to surgery (mean 8.2 pre-operatively, mean 2.6 postoperatively), the pain medication could be reduced rapidly. Conclusion The described procedure for the treatment of sacral insufficiency fractures has the potential to increase the safety of cement injection into the sacrum because of the possibility of contrast agent instillation prior to cement injection. Furthermore, the amount of cement can be reduced and additional stability can be attained due to iliosacral screw osteosynthesis compared to sacroplasty.

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

“…Preliminary clinical studies showed a decrease in implant loosening rates with cement augmentation in the osteoporotic proximal femur [20] and spine [38]. Cement augmentation of sacroiliac screw fixation has been reported in small case reports and series [41,46], and few complications were reported.…”

Assessment of the Breakaway Torque at the Posterior Pelvic Ring in Human Cadavers

“…The implant purchase may be enhanced by increasing the bone-implant contact area using modificated screws and techniques [7][8][9][10][11], or by the application of bone cement [12][13][14]. The use of cement-augmentation of standard iliosacral screws has been reported earlier [25], with promising preliminary outcomes noted when employing the use of iliosacral screws with perforations at the tip of the screws [26]. Based on our presented results, placement of screw perforations can be recommended also at the center of the screw to allow for additional cement application, especially at the lateral mass of the sacrum where a significantly diminished bone quality is expected.…”

Minimal Invasive Surgical Treatment of Fragility Fractures of the Pelvis

“…Due to lower screw anchorage, there is a higher risk of screw loosening with recurrent instability in the posterior pelvic ring (41). To enhance screw anchorage in the trabecular bone of the upper sacrum, cement augmentation of the iliosacral screws has been described (42). The technique is different from sacroplasty, where the cement is applied in the fracture gap.…”

“…Biomechanical studies have shown that stability of iliosacral screw fixation in FFP is significantly higher with cement augmentation than without (44,45). Clinical experience is still small, but results are promising (42,43).…”