In-hospital postoperative radiographs for instrumented single-level degenerative spinal fusions: utility after intraoperative fluoroscopy.

Background Context: There is a paucity of literature examining the clinical yield of in-hospital postoperative radiographs for patients who have had instrumented single-level spinal fusions with intraoperative fluoroscopic guidance. Many spinal surgeons consider postoperative standing radiographs to be the appropriate standard of care, even in patients who have an uneventful postoperative course.

Purpose: To evaluate the additional clinical yield and cost-effectiveness of in-hospital postoperative standing radiographs for patients undergoing instrumented single-level cervical and lumbar fusions in which intraoperative fluoroscopy is used. Are postoperative standing radiographs necessary before hospital discharge?

Study Design: Retrospective review of 100 consecutive degenerative spinal surgical cases in which intraoperative fluoroscopic imaging was compared with immediate postoperative radiographs using a vertebral grid mapping technique.

Methods: A retrospective review of 100 consecutive patients who had an instrumented single-level cervical (30) or lumbar (70) fusion for a degenerative spinal condition performed by the same surgeon using intraoperative fluoroscopy. All patients had a documented uneventful postoperative hospitalization without evidence of new postoperative neurologic finding. All patients had both anteroposterior (AP) and lateral intraoperative fluoroscopic images and same-hospitalization standing AP and lateral radiographic images, which were performed within 72 hours postoperatively. Intraoperative and postoperative images were compared by two observers independently using a vertebral grid mapping technique to locate screw position and control magnification differences. Study parameters included screw tip position grids, interbody graft position, segmental sagittal plane alignment, spondylolisthesis grade, and hospital charges for patient imaging and interpretation.

Results: Early instrumentation failure and/or screw position change was not observed in any patient. Seventy-four patients demonstrated a grid match for all screw tip positions on both true AP and lateral radiographs. Twenty-six patients had either a postoperative AP or lateral radiograph that was clinically malrotated and precluded comparison with the intraoperative true fluoroscopic images. Segmental sagittal alignment difference between intraoperative fluoroscopic and postoperative radiographic sagittal images averaged only 1.2° (range, 0-9) and was not statistically significant (paired Student t test, p=.88). Significant difference between intraoperative and immediate postoperative interbody graft position and spondylolisthesis grade was not demonstrated in any patient. Patient hospital billing charges for postoperative AP and lateral radiographic imaging with interpretation averaged $600.

Conclusions: In patients who have a single-level instrumented fusion and a documented uneventful postoperative course, in-hospital postoperative standing AP and lateral radiographs do not appear to provide additional clinically relevant information when intraoperative fluoroscopy is properly used. Fluoroscopy also demonstrated more consistent accuracy and a potential for significant cost savings.