Long Term Effect on Adjacent Segment Motion after Posterior Cervical Foraminotomy

OBJECTIVE: Posterior cervical foraminotomy (PCF) is a motion-preserving surgical technique. The objective was to determine whether PCF alter cervical motion as a long-term influence. METHODS: Thirty one patients who followed up more than 36 months after PCF for cervical radiculopathy from January 2004 to September 2008 were enrolled in this study. The range of motion (ROM) of whole cervical spine, the operated segment, the cranial and the caudal adjacent segment were obtained. The clinical result and the change of ROMs were compared with those in the patients performed anterior cervical discectomy and fusion (ACDF) during the same period. RESULTS: In PCF group, the ROM of whole cervical spine had no significant difference in statistically at preoperative and last follow up. The operated segment ROM was significantly decreased from 11.02±5.72 to 8.82±6.65 (p<0.05). The ROM of cranial adjacent segment was slightly increased from 10.42±5.13 to 11.02±5.41 and the ROM of caudal adjacent segment was decreased from 9.44±6.26 to 8.73±5.92, however these data were not meaningful statistically. In ACDF group, the operated ROM was decreased and unlike in PCF group, especially the ROM of caudal adjacent segment was increased from 9.39±4.21 to 11.33±5.07 (p<0.01). CONCLUSION: As part of the long-term effects of PCF on cervical motion, the operated segment motions decreased but were preserved after PCF. However, unlikely after ACDF, the ROMs of the adjacent segment did not increase after PCF. PCF, by maintaining the motion of the operated segment, imposes less stress on the adjacent segments. This may be one of its advantages.