SAFE SCREW PLACEMENT
Importance of Safe Screw Placement
Pedicle screw-based stabilization has become the gold standard for treating spinal instabilities and deformities. However, accuracy of pedicle screw placement remains a critical issue in spine surgery. In recently published papers studying screw placement accuracy:
- The average rate of misplaced screws is around 20% when using conventional techniques. (Shin 2012, Mason 2014).
- The average rate of misplaced screws is around 5% when using navigation. (Shin 2012, Mason 2014).
- In a study performed in NY (USA) (Sarwahi 2015), up to 14% of patients had at-risk screws: adjacent to blood vessels, pleura, esophagus, diaphragm or trachea.
Consequences of misplaced pedicle screws cannot be underestimated: Misplaced pedicles screws can lead to neurologic or vascular complications. Recently published clinical studies suggest that:
- 2-11% of patients have complications related to misplaced screws. (Amato 2010, Amiot 2000, Waschke 2013, Sarlak 2009, Oh 2013, Koktekir 2014, Nevzati 2014, Kerry 2014, Krauss 2014, Sarwahi 2015, Du 2016, Verma 2016)
- In patient with deformity, revision surgery due to screws at risk for the aorta was recommended in 4.7% (7/148) to 5.9% (6/101) of the patients. (Sarlak 2009, Sarwahi 2015)
- Other potential complications are screws abutting the lung, the aorta, the esophagus and the trachea as reported in a study on 140 adolescent idiopathic scoliosis patients (Kwan 2017)
Revision and Economic Impact
- The rate of revision surgery to rectify misplaced screws ranges from 1 to 11% (Amato 2010, Amiot 2000, Waschke 2013, Sarlak 2009, Oh 2013, Koktekir 2014, Nevzati 2014, Kerry 2014, Krauss 2014, Sarwahi 2015, Du 2016, Verma 2016)
- The additional cost of one revision surgery to correct a misplaced screw ranges from $17,650 to $27,768. (Hodges 2012, Watkins 2010, Sanborn 2012, Dea 2015). These studies do not include indirect costs such as health care visits, diagnostic imaging, medication and injection.