Artificial Cervical Disc Replacement

     Artificial Cervical Disc Replacement (not to be confused with lumbar disc replacement), has been FDA approved since July 16, 2007.  This is a procedure very similar in technique to the traditional anterior cervical fusion (ACDF) for treating cervical disc disease.   The proposed advantage of disc replacement over fusion is the ability to maintain normal motion at the treated segment, minimizing the problems which can occur after a fusion some years later, such as accelerated aging of the spine.

     Despite the demonstrated safety and efficacy which several of these devices have displayed, many insurance companies continue with denials, claiming investigational status.  This is frankly a bunch of hogwash mainly due to some of the less than positive results of certain lumbar artificial disc surgeries, and the insurance companies' inability to distinguish between the two (one is in the neck, the other in the back).  The other possible reason is a lack of superiority data.  Because of the high cost of running clinical trials, most device companies prefer to perform "noninferiority trials" instead of "superiority trials" since the former require less statistical power and therefore fewer patients and less money.  All trials to date on these devices have been noninferiority trials which gives insurance companies a window for denial.

     A recent study by McAfee, et al,  in the journal Spine 2012 performed a meta-analysis of the available non-inferiority trials, generating enough numbers to demonstrate significant superiority of artificial cervical disc replacement over fusion.  Although the statistics behind this aren't as clean as a larger double-blind controlled trial, this is currently the best evidence we have that artificial cervical disc replacement is a better operation (in the appropriate patients) than ACDF.  Below is the link:

http://journals.lww.com/spinejournal/Abstract/2012/05150/A_Meta_Analysis_of_Comparative_Outcomes_Following.7.aspx

     This data also completely jibes with my personal experience with this technique.   It is quite similar to a fusion in nature so is easy for surgeons to learn,  can be performed outpatient, and clinical results are usually excellent.   Here is a link to a live video of a cervical disc replacement:

For more information about lumbar and cervical artificial disc replacement:

http://www.spineuniverse.com/treatments/surgery/artificial-disc-replacement-surgery

   

Minimally invasive cervical surgery.
   
There are basically two approaches to the cervical spine: anterior and posterior.  Anterior approaches work well, but generally involve fusions.  Posterior operations allow motion preservation, but often are quite painful from extensive dissection of the sensitive neck muscles.  Frankly these operations tend to hurt more than comparable lumbar operations.
     The minimally invasive approach to the cervical spine minimizes this pain by serially dilating through the muscles and using tubular retractors.  The only difference between cervical and lumbar MISS procedures is the smaller size tubes used in the neck.  These types of operations are performed on patients with cervical disc disease, but can also be done for cervical stenosis as well.
     There is a dramatic decrease in post-operative pain and blood loss with this technique.  Length of stay is much less as well, typically this is an outpatient procedure.
     Here is a great video of the disc procedure (by another doctor)

            Minimally Invasive Posterior Cervical Disc Surgery

I'll post a movie of a cervical decompression for stenosis when I get the video editing done

MILD Procedure

     One of the purposes of this blog is to raise awareness regarding procedures this author has  concerns about. The MILD procedure, as an example, is being marketed around the US as a minimally invasive way to percutaneously decompress lumbar stenosis rapidly in an oupatient setting through one or two small stab wounds.

Mild procedure link:

http://www.mildprocedure.com/

     I have personally trained in this procedure, and although intrigued, I have have not pursued it for my patients.   My reason is that although relatively safe,  this procedure is performed purely under X-Ray guidance with no direct visualization of the neural elements.  This raises the risk of leaving some residual stenosis in my opinion .  Many other surgeons have had similar concerns  about this procedure and have been hesitant as well.  Other spine physicians (pain specialists, etc) have taken up this technique with more enthusiasm and marketed it heavily.   

     This months' issue of the journal: Neurosurgery confirms this in a prospective small study of ten patients who had this procedure.  Of the ten patients who had the MILD procedure (referred to as PRLL), 6 patients required an additional laminectomy because of residual symptomatic stenosis within a short time period.  Obviously this is a very small study which needs to be confirmed by further work.  This is to my knowledge the first independent evaluation of the technique outside of an industry trial, however, and certainly a 60% failure rate gives one significant pause.  

     Frankly, conventional minimally invasive techniques for lumbar stenosis also allow a rapid outpatient treatment of this condition as well.  In the absence of more favorable results, one should give pause before pursuing this procedure.

Here is the link:

http://journals.lww.com/neurosurgery/Fulltext/2012/07000/Failure_of_Percutaneous_Remodeling_of_the.12.aspx