Does Interbody fusion change ASD in disc next to the fusion? – 10 years MRI follow-up on a randomized controlled study — The International Society for the Study of the Lumbar Spine
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  3. Does Interbody fusion change ASD in disc next to the fusion? – 10 years MRI follow-up on a randomized controlled study

Does Interbody fusion change ASD in disc next to the fusion? – 10 years MRI follow-up on a randomized controlled study (#1119)

Kristian Høy 1 , Lin Ding 2 , Thomas Andersen 3 , Niels Egund 4
  1. Orthopedic Department, Spine section, Aarhus University Hospital, Denmark, Aarhus N, Danmark, Denmark
  2. Spine Unit, The Rizhao Hospital of traditional Chinese medicine, Rizhao,, China
  3. Department of Orthopedics, , Rigshospitalet University of Copenhagen, , Copenhagen, Denmark
  4. Department of Radiology, , Aarhus University Hospital, Denmark, Aarhus N, Danmark, Denmark

INTRODUCTION: Due to the increasing number of spinal procedures performed worldwide, adjacent degenerative disease (ASD) has become a new focus area. Whether ASD is a matter of normal degenerative development in the disc over time or a result of increased stiffness and stress due to the fusion is still debated. Nowadays TLIF is the most widely used interbody fusion method. The use of inter- body fusion has be claimed to reduce the degenerative changes in the spared free disc over time due to better sagittal balance and restoration of the lost lumbar lordosis. Aim: To compare degenerative changes on MRI between PLF and TLIF 10 years post surgery. 

METHODS: 100 patients included in a prospective RCT between inter-body fusion and Instrumented posterolateral fusion were seen in the outpatient clinic and offered a MRI at long term follow-up. All MRI were classified according to degree of Modic changes, Pfirmanns classification, Schizas classification and Fardon and Milette classification in order to show the degree of degeneration of the discs above and below the fusion. The grading was done by to independent observers without any contact to the patient. In patients who underwent secondary surgery, the MR prior to that was used and the degenerative changes measured according to the above mentioned classifications. 

RESULTS: 79 patients were available for long-term follow up. The groups were equal regarding sex, age, diagnosis and number operated levels. The follow up length was 9.6 years. The Modic change found at the first upper level was none in (85%/68%), mostly grade 2 (12%TLIF/26%PLF). There were no significant difference between the two groups p=0.274. Nearly all patients did not show any sign of treatment needs regarding spinal stenosis according to Schizas classification 92%/92% only 8/8% had type C and D at the 1 proximal level 9.6 year after surgery. No difference between groups could be detected p = 0.930. The Pfirmann grading at the first proximal level did not show any difference between groups,too p = 0.952. 

DISCUSSION: In a prospective randomized design the use of inter-body fusion do not reduce the amount of degenerative changes in the first proximal disc in comparison to a normal posterolateral instrumented fusion.

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