Comparative Study of Neck Pain in Relation to Increase of Cervical Epidural Pressure During Percutaneous Endoscopic Lumbar Discectomy

Study Design. A prospective study. Objective. By monitoring cervical epidural pressure (EP) changes throughout the procedure, we intend to discover the effect of percutaneous endoscopic lumbar discectomy (PELD) on cervical epidural pressure and whether there is a correlation between posterior neck pain and increased cervical EP, which is known to have a linear correlation with intracranial pressure (ICP). Summary of Background Data. Patients sometimes complain of posterior neck pain during PELD. Due to the massive irrigation fluid used during the procedure, the possibility of increased ICP as the cause is quite strong. Methods. Twenty-eight patients undergoing PELD with ASA physical status 1 or 2 were enrolled in this study. In all patients, a cervical epidural catheter was placed at the C6-C7 level before the procedure and was connected to a pressure transducer. Cervical EPs were monitored continuously throughout the procedure. Initial stabilized EP (EP), EP at the time of neck pain, maximal EP during the procedure, and EP at the end of the procedure were checked. Neck pain onset time from the beginning of irrigation and total irrigation time were also checked. Results. Of 28 patients, 8 patients complained of neck pain. Neck pain onset time from the beginning of irrigation was 35.6 +/- 11.3 (mean +/- SD) minutes. The EP at the time of neck pain (52.9 +/- 9.2 mm Hg) was significantly higher than the maximal EP in patients without neck pain (34.8 +/- 14.7 mm Hg). In all patients who complained of neck pain, the cervical EP at the time of neck pain showed pressures above 37 mm Hg. The maximal EP in those with neck pain (73.6 +/- 25.8 mm Hg) was also significantly higher than the EP in those without neck pain (34.8 +/- 14.7 mm Hg). In a correlation study, patients with higher maximal EPs had higher probabilities of having neck pain. In 6 of 8 patients, an abrupt increase in EP was observed after the onset of neck pain, while in the other 2 patients, the procedure ended just after neck pain appeared. Conclusion. Neck pain occurring during PELD is associated with a highly increased cervical EP generated by continuous infusion.