Fri., 10/14/11 Pelvis & Spine, Paper #43, 10:23 am OTA-2011
An Analysis of the Demographic and Technical Characteristics Associated With Iliac Cortical Perforation During Insertion of Iliosacral Screws
J. Stuart Melvin, MD1; Nicholas Pulos, BA2; Keith Baldwin, MD, MPH, MSPT2;
Amer J. Mirza, MD3; Michael J. Gardner, MD4; Samir Mehta, MD2;
1Carolinas Medical Center, Charlotte, North Carolina, USA;
2University of Pennsylvania, Philadelphia, Pennsylvania, USA;
3Oregon Health & Science University, Portland, Oregon, USA;
4Washington University, St. Louis, Missouri, USA
Purpose: Iliosacral screws are a common fixation method for posterior pelvic ring injuries, and are associated with minimal blood loss and low rates of infection and nonunion. Reports of complications for iliosacral screws have focused on nerve and vessel injury. Perforation of the outer cortex of the ilium during tightening of iliosacral screws has been observed, but seldom reported. This complication may compromise fixation stability. This investigation sought to identify risk factors associated with breach of the outer iliac cortex during iliosacral screw insertion.
Methods: 142 consecutive patients who had undergone iliosacral screw fixation of the posterior pelvic ring were retrospectively identified from 3 Level 1 trauma centers. The demographic and technical characteristics of each case were reviewed. Postoperative CT scans were scrutinized for any evidence of washer penetration through the outer table of the ilium.
Results: 236 iliosacral screws with washers were inserted for an average of 1.66 screws per patient. 28 screws (11.9%) in 26 patients (18.3%) perforated the outer cortex of the ilium. Patients with screw perforation were older (52.61 years vs 38.6 years; P = 0.0002) and more likely to be diabetic (P = 0.0071). Additionally, perforated screws were more often fully threaded (P = 0.0315) and patients with a perforated cortex had significantly more screws inserted (1.92 vs 1.60; P = 0.037). Sex, time to surgical fixation, laterality, smoking status, OTA fracture classification, and surgeon did not affect the rate of cortical breach.
Conclusion: Perforation of the outer iliac cortex is common during insertion of iliosacral screws and may lead to an increased number of screws being inserted. Factors increasing rates of cortical perforation are linked to poor bone quality, such as age and diabetes, and also fully threaded screws. These factors should be kept in mind during final iliosacral screw tightening. Additionally, the 20° “roll-over” view tangential to the outer table can help visualize complete washer seating and may avoid perforation. Further research is warranted to evaluate the effect of cortical perforation on stability, union rate, and outcomes.
Alphabetical Disclosure Listing (628K PDF)
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.