Foraminal Stenosis as a Cause of Postdiscectomy Syndrome

To reveal the relation between postdiscectomy syndrome and foraminal stenosis due to height loss of disc level in patients operated for one-sided L5-S1 disc herniation.

In this study, 100 operated patients due to L5-S1 one-sided disc herniation were included. Mean age was 46.60 years (±10.52 years), the youngest patient was 26 and the eldest was 74 years old. Foraminal height, width, and intervertebral disc height were measured via computed tomography (CT). The diameters were compared preoperatively and postoperatively. The relation between the measurements and clinic findings was investigated.

Six months after discectomy, for the operated side, the mean foraminal height decreased from 16.78 ± 1.75 mm to 14.43 ± 1.62 mm (p < 0.05) and the mean foraminal width decreased from 6.30 ± 1.43 mm to 5.34 ± 1.56 mm (p < 0.05). For the nonoperated side, the mean foraminal height decreased from 14.71 ± 2.05 mm to 14.55 ± 1.86 mm (p > 0.05) and the mean foraminal width decreased from 6.13 ± 1.95 mm to 5.84 ± 1.84 mm (p < 0.05). According to the correlation test, for the operated side, a statistically significant relationship was determined between the decrease in foramen height and leg pain visual analog scale (VAS) score. Moreover, a statistically significant relationship was determined between the decrease in the posterior side height of the disc level and the leg pain VAS score.

Overall, we found that after microdiscectomy, as the height of the foramen decreased, leg pain also increased. Moreover, the decrease in the posterior side height of the disc level was associated with an increase in leg pain. Therefore, over time, the collapse of the disc distance decreases the foramen height, which causes leg pain. After microdiscectomy, in patients whose leg pain was relieved at first but started again after a time, the foramen and disc level diameters should be checked.