The utility of repeated postoperative radiographs after lumbar instrumented fusion for degenerative lumbar spine.

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

To assess the impact that routine postoperative radiographs have in clinical outcome and clinical decision-making.

SUMMARY OF BACKGROUND DATA

No standard exists that outlines how often and when radiographs should be taken after lumbar fusion. Routine postoperative radiographs can be a source of inconvenience and cost to patients, radiation exposure, and possibly, confounding information.

METHODS

The patients who underwent a single or multilevel lumbar instrumented fusion were investigated. At each time-point after surgery, it was noted if they demonstrated new symptoms or clinical deterioration. The Fisher exact test was used to analyze the categorical data.

RESULTS

Sixty-three patients (25 males and 38 females) were identified with a mean age of 52 years (range, 20-87). Plain radiographs were taken at 269 visits including all time-points. In 17 (6.3%) visits, abnormal findings were found in 13 patients, including suspected pseudoarthrosis on radiographs (n = 10) and adjacent segment disease on radiographs (n = 3). They were found during 11 of 50 visits (22%) in the patients with new symptoms or clinical deterioration and during 6 of 219 visits (2.7%) in the asymptomatic patients. The probability of an abnormal finding was significantly lower in the asymptomatic patients (P < 0.001). Before the 6-month follow-up, abnormal findings were found in 1 of 111 visits (0.9%) and in 16 of 158 visits (10%) at the 6-month follow-up or later. The probability of an abnormal finding was significantly lower before the 6-month follow-up (P < 0.001). In six of the seven symptomatic patients (86%) with suspected pseudoarthrosis on radiographs, pseudoarthrosis was initially suspected between 6 and 12 months after surgery.

CONCLUSION

This study suggests that plain radiographs should be performed as indicated clinically rather than routinely after instrumented lumbar fusion. The vast majority of asymptomatic patients do not require routine postoperative radiographs.