Comment on the paper “Contralateral radiculopathy after transforaminal lumbar interbody fusion” (Travis Hunt et al.)

The authors present a case of a spondylolisthesis with obvious foraminal stenosis on both sides as shown on the preoperative MRI. A proper operative technique in this case would include a restoration of disc height and the (partial) reduction of the slip. This technique would widen both foramina and no complication like opposite nerve root compression would occur. If reduction or disc height restoration cannot be achieved, decompression of both foramina should be performed. In mild cases a simple posterior distraction may be enough. In their paper the authors agree to this point as they write “decompression of the opposite side has not been judged necessary in the past as it has been commonly assumed that the TLIF spacer increases the disc space height and the foraminal height in the opposite foramen of the TLIF approach.” However, it seems that in the current case the authors failed to achieve restoration of disc height. Figure 7 shows differences between the preoperative and the postoperative CT scan of 1 mm (4 vs. 5 mm) and 1.5 mm (6.5 vs. 8 mm), respectively. The same is true for the “decrease” of foraminal height of 2 mm. I think that these measurements are not reliable since there is no calibration and no matching between the slices. Hence no obvious increase in disc height or decrease in foraminal height can be measured accurately. Anyway, the clinical significance of 1 or 2 mm of reduced foraminal height, if really present, seems to be questionable.