[fortitudine]

Do we know any more about this issue? As I'm a potential ProDisc-C candidate, this worries me.


Posted December 03, 2006 10:56 AM December 03, 2006 10:56 AM
Folks,

An informed member was kind enough to share some recent information on ProDisc cervical and heterotopic ossification (autofusion).

I am quite puzzled by this and would have liked to have had the “story behind the numbers” before posting. However, I urge you all to NOT jump to any conclusions about the efficacy of the ProDisc C (or any other cervical discs) until more contextual information can be found on this issue. As you seasoned folks know, ProDisc C patients on this forum have done quite well.

Related topics from this board on HO here.
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Heterotopic Ossification in Total Cervical Artificial Disc Replacement.

Spine. 31(24):2802-2806, November 15, 2006.
Mehren, Christoph MD *; Suchomel, Petr MD, PhD +; Grochulla, Frank MD *; Barsa, Pavel MD +; Sourkova, Petra MD +; Hradil, Jan MD +; Korge, Andreas MD *; Mayer, H Michael MD, PhD *

Abstract:
Study Design. Prospective clinical study enrolled in 2 centers (Munich and Liberec) as part of a prospective European multicenter study with ProDisc C (Synthes Inc., Paoli, PA).
Objectives. The first goal of the study was to evaluate the rate of heterotopic ossifications identified with plain radiograph following total cervical disc replacement (TCDR). The second goal was to show whether segmental motion can be preserved, and whether TCDR can provide improvement of the patient's ability to perform activities of daily living as well as a decrease of pain.

Summary of Background Data. Only a few reports about the radiologic outcome after TCDR are published so far. Heterotopic ossification is a well-known phenomenon after total hip arthroplasty. The rate of heterotopic ossification following TCDR is unclear.

Methods. The radiographs of 54 patients (in total, 77 implanted prostheses) were analyzed 1 year after TCDR with a ProDisc C prosthesis. We classified the heterotopic ossification in 5 grades according to a recently published classification system for lumbar total disc replacement. For clinical parameters, the visual analog scale and the Neck Disability Index were evaluated preoperatively and 1 year postoperatively. The Student t test and Wilcoxon test were used for statistical analysis.

Results. In 26 treated segments (33.8%), no heterotopic ossification was detectable. Grade 1 ossifications were present in 6 levels (7.8%). A total of 30 segments (39.0%) showed grade 2 ossifications. Heterotopic ossifications that led to restrictions of the range of motion were present in 8 cases (10.4%). One year postoperatively, 7 cases (9.1%) had a spontaneous fusion of the treated segment. The clinical parameters improved significantly and were similar to previous reports about TCDR.

Conclusions. Only 33.8% of the patients did not show any signs of heterotopic ossification, and the rate of spontaneous fusion after TCDR 1 year after surgery was unexpectedly high. There were 49.4% of the patients with grade 2-3 ossification, which lets us suspect an even higher rate of spontaneous fusion after long-term follow-ups. Motion preservation after TCDR is only guaranteed if spontaneous fusion can be prevented. Thus, mobility of the implanted segments needs to be further studied.