Intraoperative ISO-C CT may reduce costs for posterior cervical fusion

Hecht AC. Clin Orthop Relat Res. doi:10.1007/s11999-010-1603-2.

For patients undergoing posterior cervical fusion, intraoperative 3D fluoroscopy may be a safe and cost-effective alternative to postoperative CT.

Andrew C. Hecht, MD, and colleagues at The Mount Sinai Medical Center, New York retrospectively reviewed the records of 87 patients who underwent posterior cervical decompression and instrumented fusion for multilevel cervical spondylosis with myelopathy. The investigators recorded patients in whom a lateral mass, pars or pedicle screw was removed or revised based on intraoperative 3D fluoroscopy (ISO-C CT).

Seven patients required screws changed based on 3D fluoroscopy results: 0.5% of lateral mass screws, 3.1% of thoracic pedicle screws and 15% of C2 pars screws, the authors wrote. No patients whose hardware was evaluated with ISO-C CT required additional surgery related to hardware failure, malposition or cutout.

These results show that intraoperative ISO-C CT can reduce costs if it prevents a return to the operating room, according to the authors.

“If every malpositioned screw has the potential to be symptomatic, then 240 patients must have screws placed to be cost-effective,” they wrote in their abstract.

The authors present interesting data supporting the benefit of intraoperative CT in assessing posterior cervical hardware placement. While few people would disagree with the benefits of intraoperative CT, I do not believe that the cost-effective analysis is supported by their results. The authors use the assumption that seven patients would be spared potential revision surgeries for misplaced hardware. Yet, they admit in the article that the majority of misplaced hardware is asymptomatic and therefore may not require revision. This is well documented in the spine surgery literature. Additionally, many of these malplaced screws may have been detected by routine intraoperative 2D fluoroscopy.

Finally, the assertion that the ISO-C CT can replace postoperative CT evaluation as the standard of care in patients undergoing posterior cervical fusion is based on the false premise that postoperative CT is the standard of care. While postoperative CT is useful in evaluating hardware placement in patients with instrumentation in transitional areas such as the occiptocervical junction and the cervicothoracic junction, where visualization may be difficult, the majority of patients with instrumentation outside of these two areas are satisfactorily evaluated with routine radiographs. CT is reserved for select patients with new onset or persistent symptoms.

Despite the limitations of this study, intraoperative CT does give the surgeon a new tool to evaluate the anatomy and placement of instrumentation in real time prior to the patient leaving the operating room, which benefits the surgeon, patient and the hospital.

— Norman B. Chutkan, MD, FACS
Chairman, Department of Orthopaedic Surgery
Medical College of Georgia
Augusta, Ga.