Preserving The Preexisting Asymptomatic Degenerative Discs Through Anterior Cervical Discectomy And Fusion In Treatment Of Multisegmental Cervical Spondylosis

Objective: The degenerative discs of multilevel cervical degenerativedisease can be all the pathogenic segments. It can also be one or two discs isthe responsibility segment and it can be said asymptomatic degeneration. Todetermine the asymptomatic degenerative disc should be underwent acomplete neurological examination, radiological parameters(especiallycervical MRI),even need to underwent electrophysiological examination. Forthese asymptomatic degenerative discs should be decompressed duringsurgery or to be reserved still no conclusion. To investigate the clinical effectof preexisting asymptomatic degenerative discs adjacent to the fused levelthrough anterior cervical interbody fusion in treatment of multisegmentalcervical spondylosis, and to observe the discs’ progression of degenerativeconditions. At last to discuss whether need to fuse the preexistingasymptomatic degenerative discs adjacent to the fused level of anteriorcervical interbody fusion.Method: The clinical date of56cases of anterior cervical interbodyfusion who preserve the preexisting asymptomatic degenerative discs adjacentthe fused level in our department from Nov2011to Jan2014were analyzed.Of these,38were men and18were women and the average age at operationwas52years (range,34to73years). The average length of follow up was24（20~29）months. Of the56patients,27had one level,21had two levels offusion. And8had anterior cervical corpectomy and fusion. To determine theasymptomatic degenerative disc should be underwent a complete neurologicalexamination. X-rays, CT and MRI were conducted before surgery.Electrophysiological examination even need to be underwent if necessary. The neurological status of the patients was assessed by the Japanese OrthopaedicAssociation Scale (JOA) before surgery and after surgery of3months,1yearand at last follow-up. JOA improvement rate is calculated as (postoperativescore-preoperative score)/(17-preoperative score).The patient’s findings of acomplete neurological examination, which included strength, sensory, andreflex testing and the new symptoms were documented at each follow-up visit.The complete neurological examination combined magnetic resonanceimaging can confirm the presence is caused by the reserved degenerated level.Comparing the X-ray and MRI between preoperative and postoperative, thediscs’ progression of degenerative conditions were assessed according to thefollowing criteria, Signal change in intervertebral disc, disk space narrowing,progressing of the disk bulging or herniation, informing vertebral osteophytesor osteophytes increased.Results:56patients were followed up with a mean period of24（20~29）months. The preoperative JOA score was8.4±0.4points. The score threemonth after the operation was13.3±0.3points; The score1year after theoperation was14.9±0.3points; The postoperative JOA score at the lastfollow-up was14.2±0.4，and on average the recovery rate was66.3%;28of56were excellent,27good,1fair,0poor. There were2cases who developed newsymptomatic adjacent-segment disease, and undergone careful conservativetreatment had good effect.38discs had varying degrees progression ofdegenerative conditions among36patients.11discs(11%) had decrease insignal intensity. There are2vertebral osteophytes or osteophytes increased.There is on findings about the disc space narrowing and posterior discprotrusion.Conclusion: Selectively segmental cervical decompression throughanterior approach can achieve significant effect. Although the preexistingasymptomatic degenerative discs which were preserved had varying degreesof progression after24（20~29）months, but the cases they caused the newsymptomatic adjacent segment disease are very few. It also can shorten theoperation time, reduce surgical complications and reduce the financial burden on patients.