Michelle: Thanks.
Its odd to hear that surgeons still use a ruler on Xrays. The radiographic analysis software is very advanced these days. Various papers reveal measurements in the order of microns (1/1000 mm). I was really impressed with the measurement tools in Jview. WE know it is exact because we know the exact height of the Prodisc implanted (11mm in the center).
Dicom,
http://www.pubmedcentral.nih.gov/art...?artid=1888420
Also - here for example, Dr. James Yue states the disc height increases:
Quote:
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Radiographic analysis revealed an affected disc height increase from 4 mm to 13 mm (P < 0.05) - James Yue
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But, the Prodisc-L only comes in heights of 10, 12, 14mm. (that is the measure of the posterior, while there is a tilt on the upper plate so that the front is actually much more open). So, since the max disc height was 13mm - we can tell they never used a 14mm device. Since they remove the disc material, you can only have maximum 14mm Post-ADR. Disc height is extremely important (as noted by many surgeons) in that the increase is amplified in the fulcrum-effect on the facets. Think of a hammer pulling a nail - where the nail is where the facets are. The vertebral-body-lamina-facets have the same shape. The hammer-handle is the spinal column.
Thus this
article authored by Yue and Bertagnoli:
Quote:
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"Patients with evidence of intra-articular facet degeneration, specifically evidence of joint space narrowing with or without cystic changes, were excluded from the study."
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Also interesting in that article: The
graphs in that report reveal that the regular & occasional use of Tramadol reduced from 27% pre-op to only 25% at 24 monts post-op ... for smokers, and 'reduced' from 26% to 30% for non-smokers.
I think we have to be realistic and realize that a lot of people will be experiencing permanent pain ... especially if their ADR device is 1.5x too tall, their Pre-OP facets are Grade IV arthritic, and their pre-op disc was collapsed to bone-on-bone. In this case, we can be sure it wont work-out for 98.2% of the patients. My guess is maybe the number should be backwards - like 98.2% failure ... kinda like tramadol usage reduces from 26% to 30%.
