Pro Disc Disc Replacement
ProDisc Disc Replacement Study - "requiring revision surgery at the index level in 8.7% of the patients"
Also see ProDisc long term complications
"reports of 32% increase in progression of facet arthrosis post-Prodisc disc replacement surgery"
Dr. Ritter-Lang has done close to 300 M6 Lumbar disc replacements without any plate migration or revisions required.
ProDisc-L Study
Clinical Results of Total Lumbar Disc Replacement With ProDisc II: Three-Year Results for Different Indications.
Clinical Case Series
Spine. 31(17):1923-1932, August 1, 2006.
Siepe, Christoph J. MD; Mayer, H Michael MD, PhD; Wiechert, Karsten MD; Korge, Andreas MD
Abstract:
Study Design. Prospective study analyzing midterm clinical results of total lumbar disc replacement (ProDisc II) for different indications.
Objectives. To assess functional outcome after total lumbar disc replacement (TDR) treated for varying indications.
Summary of Background Data. Despite its frequent use and increasing popularity, indications and contraindications for TDR have not been defined precisely at this stage and remain a matter of debate, leading to disc replacement procedures in a variety of pathologies that have not yet been evaluated and compared separately.
Methods. Patients meeting inclusion criteria were evaluated prospectively according to Visual Analogue Scale (VAS), Oswestry Questionnaire, SF-36, and numerous clinical parameters. Indications included degenerative disc disease (DDD), DDD with accompanying soft disc herniation (nucleus pulposus prolapse, NPP), osteochondrosis following previous discectomy, and DDD with presence of Modic changes. Postoperative improvement was recorded and analyzed for influence of preoperative diagnosis.
Results. Overall, 92 patients from four groups with a mean follow-up of 34.2 months (minimum, 24 months) achieved significant and maintained improvement from preoperative levels (P < 0001). Patients with DDD + NPP achieved results significantly better than patients from the other groups (P < 0.05). Presence of Modic changes or previous discectomy did not influence outcome negatively. Improvement was achieved for both monosegmental and bisegmental disc replacements (P < 0.05), nevertheless with significantly inferior results for bisegmental interventions at 12- and 24-month follow-up and considerably higher complication rate. While older patients were still highly satisfied with postoperative outcome, better functional outcome was observed in younger patients.
Conclusion. Present data suggest beneficial clinical results of TDR for treatment of DDD in a highly selected group of patients. Better functional outcome was obtained in younger patients under 40 years of age and patients with degenerative disc disease in association with disc herniation. Multilevel disc replacement had significantly higher complication rate and inferior outcome. Results are significantly dependent on preoperative diagnosis and patient selection, number of replaced segments, and age of the patient at the time of operation. Because of significantly varying outcomes, indications for disc replacement must be defined precisely.
Results
In 92 patients that received total lumbar disc replacement with ProDisc II, a total of 108 disc prosthesis were implanted. Thirty-three (35.9%) of the patients were male, and 59 (64.1%) were female. The average age of the patients was 42.5 years (range, 21.9-66.1 years; SD, 9.1 years) with an even age distribution over all groups.
The operations were performed monosegmental (n = 77; 83.7%), bisegmental (n = 14; 15.2%), or multisegmental (3 levels, n = 1; 1.1%); operated levels. Monosegmental operations were predominantly performed at the lumbosacral junction (n = 59; 64.1%) and at the segment floating above the lumbosacral junction (n = 17; 18.5%). Including multisegmental procedures performed at the lumbosacral junction (n = 15; 16.3%), the lumbosacral motion segment was involved 74 times (80.4%).
Intraoperative/Perioperative Data
The overall operating time averaged 115 minutes for monosegmental operations (range, 58-210 minutes; SD, 32 minutes) and 190 minutes for bisegmental procedures (range, 103-300 minutes; SD, 46 minutes). The recorded volume of blood loss averaged 100 mL over all groups (range, 10-350 mL; SD, 65 mL). Patients were mobilized from the first postoperative day without additional support. There were no significant differences for intraoperative data between the different groups.
Group Analysis
Results for preoperative levels of VAS and ODI as well as postoperative improvement for different indications are outlined. With the exception of the VAS for Groups 2 and 3 (P = 0.04), there were no significant differences before surgery between the different groups.
Patients from all groups as well as combined data showed highly significant postoperative improvement for VAS and ODI scores and were able to maintain these results until last follow-up (P < 0.001; Figure 3). For Groups 1, 3, and 4, we were able to detect a minor decline for both ODI and VAS scores from 36-month to 48-month follow-up. Nevertheless, postoperative improvement was still significant (P < 0.05).
Postoperative results for VAS (A) and ODI (B) for different indications over time. DDD = degenerative disc disease; NPP = nucleus pulposus prolapse. Student's t test was performed to compare preoperative with postoperative data (VAS, ODI) for Groups 1-4. P < 0001 for all groups and combined data.
Forty patients with DDD and without any other accompanying pathologies (Group 1) were used as a reference for comparison with the remaining groups.
Modic changes were seen in 23 patients. Presence of Modic changes did not have any significant influence on overall outcome compared with patients from Group 1.
Similarly, no significant difference could be detected between a preselected group of patients that had previously undergone discectomy and those without (comparison Group 1 vs. Group 3; P > 0.3). Sciatica in this group was present before surgery in 12 out of 17 patients and improved in 8, leaving 4 patients with no benefit as regards their leg pain. Sciatica was not caused in any of the patients from this group nor did preexisting radicular leg pain deteriorate as a cause of disc replacement after previous surgical intervention.
Overall, postoperative differences between Groups 1, 3, and 4 were not statistically significant. Best results were achieved for patients with DDD and coexisting contained soft disc herniation (Group 2, Figure 4). Results for postoperative VAS, ODI, as well as overall improvement at last follow-up for patients from this group were significantly superior to Groups 1, 3, and 4 (P < 0.05). Excellent results were maintained throughout the postoperative course with a mean follow-up of 33.1 months. All patients (n = 12; 100%) reported highly satisfactory outcome and would retrospectively opt for an operation again.
Disc replacement in a patient with back pain from symptomatic disc degeneration and accompanying central disc herniation at L5-S1 (A and B). Signs of adjacent disc degeneration at L4-L5. (C and D) Radiograph at the 36-month follow-up shows retained disc height at L4-L5 and satisfactory implant positioning. Clinically, the patient experienced significant and lasting improvement from his previous complaints.
Subjective Outcome Evaluation
Asked for their subjective evaluation of total disc replacement, 65.2% of the patients were completely satisfied at the time of their last follow-up and recorded their result as excellent, 17.4% were satisfied and marked good results, and another 17.4% of the patients were not satisfied with their personal outcome.
Thus, 82.6% of the patients were satisfied or highly satisfied overall, which is reflected in the amount of 85.7% of patients that would retrospectively undergo disc replacement operation again; 12.7% of the patients would not decide for a repeat operation, while 1.6% of the patients were unsure. These results are in continuity with our previously published preliminary data.[22]
Monosegmental Versus Bisegmental Operations
Comparing monosegmental versus bisegmental disc replacements, statistical analysis showed significant improvement for both groups at 3- and 6-month follow-up as regards evaluation of VAS and ODI scores (P < 0.001) (Figure 5). While patients with monosegmental disc replacements were able to maintain excellent results throughout the postoperative course showing highly significant postoperative improvement for VAS and ODI (P < 0.001), a deterioration in the results was noted for bisegmental operations 12 and 24 months after surgery. As for ODI scores, there was still a strong tendency toward significant improvement from preoperative level at 12 and 24 months after surgery (P = 0.07), and improvement for VAS was still statistically significant (P = 0.01). Nevertheless, there was a significant difference comparing outcome of bisegmental TDR with monosegmental operations at 24 months after surgery (P = 0.02 for VAS; P = 0.01 for ODI, Mann-Whitney U-Wilcoxon rank sum test).
Postoperative development and comparison of VAS (A) and ODI (B) for monosegmental versus bisegmental disc replacements. ODI = Oswestry Disability Index; VAS = Visual Analogue Scale; TDR = total lumbar disc replacement. (A) +P = 0.01 paired t test, comparison of preoperative versus postoperative bisegmental TDR. oP < 0.001 paired t test, comparison preoperative versus postoperative monosegmental TDR. #P = 0.02 Mann-Whitney Test for comparison of monosegmental versus bisegmental TDR at 24 months postoperation. (B) +P = 0.07 paired t test, comparison of preoperative versus postoperative bisegmental TDR. oP < 0.001 paired t test, comparison of preoperative versus postoperative monosegmerntal TDR. #P = 0.01 Mann-Whitney test for comparison of monosegmental versus bisegmental TDR at 24 months postoperation.
From a clinical point of view, this can be backed up by patient satisfaction rates. While 85.7% of patients with monosegmental disc replacements reported good and excellent subjective results, this is opposed to only 64.3% of patients after bisegmental disc replacement at the time of last follow-up.
Level of Disc Replacement
To evaluate the influence of the level of disc replacement on postoperative outcome, data for VAS and ODI from patients with monosegmental disc replacements performed at the lumbosacral junction were compared with disc replacements performed at the level above the lumbosacral junction. No significant difference was observed between the two groups, neither before surgery nor at any stage throughout the postoperative course. There was a trend toward better outcome for ODI for disc replacements performed at the level above the lumbosacral junction. However, statistical testing did not reveal any significant difference (P > 0.05).
Back to Work
At the last follow-up, 56.0% of the patients were back in their old working environment without restrictions in full time labor, while 4.4% were back in their old job but on a limited time scale; 7.7% of the patients had reorganized their professional life after surgery and found themselves in a new working environment.
Overall, 29% of the patients were on sick leave already before surgery, but only 1.1% of these were not able to benefit as regards their working status; 15.4% of the patients received Workers' Compensation, 3.3% received an old-age pension, and 12.1% of the patients were recorded as unemployed at last follow-up due to economic reasons despite the fact that from a medical point of view the patients were in a good condition.
Thus, the overall rate for patients being back in their old job or some kind of modified professional activity at their last visit summed up to 68.1% following TDR.
Age
Analyzing age from 92 patients, we found an even age distribution over all groups. This cohort was further subdivided according to age into five different subgroups by decades starting from the age of 20 to analyze influence of age on clinical outcome. Because of the small number of patients 20 to 30 years of age and ≥60 years of age, these groups were not used for statistical analysis, leaving three age groups (30-40, 40-50, and 50-60 years, respectively). Patients from each group similarly showed significant improvement for VAS, ODI, and good to excellent subjective patient evaluation (P < 0.05;.
Comparing postoperative results from patients 40 to 50 years of age with patients 50 to 60 years of age, we did not find any statistical significance. Best results were achieved for patients 30 to 40 years of age at the time of the operation. Postoperative improvement for VAS and ODI was significantly better in this age group compared with patients 40 to 50 or 50 to 60 years of age. Nevertheless, subjective outcome evaluation still showed highly satisfactory results, with 93.3% of patients 50 to 60 years of age reporting good to excellent clinical outcome at last follow-up.
Complications
The overall complication rate was 19.6%, requiring revision surgery at the index level in 8.7% of the patients and another 2.2% at the non-index level following TDR. There were no vertebral body fractures as reported previously by other authors. Furthermore, there were no direct vessel lacerations in any of the patients. Complication rate was considerably higher for bisegmental disc replacements (n = 5 of 14 operations; 35.7%) compared with monosegmental interventions (n = 11 of 77; 14.3%).
Dr. Ritter-Lang has done close to 300 M6 Lumbar disc replacements without any plate migration or revisions required!
Choose your implant carefully!
ProDisc-L Articles
Vertical Split Fracture of the Vertebral Body Following Total Disc Replacement Using ProDisc: Report of Two Cases
Journal of Spinal Disorders & Techniques:
October 2005 - Volume 18 - Issue 5 - pp 465-469 read the abstract > >
Bilateral Pedicle Fractures Following Anterior Dislocation of the Polyethylene Inlay of a ProDisc Disc Replacement
Spine:
1 June 2005 - Volume 30 - Issue 11 - pp E311-E314
doi: 10.1097/01.brs.0000164135.03844.b6
read the abstract > >
Spinal Kinetics M6
"The kinematic signatures of the intact human disc and the M6 artificial disc are nearly identical."
"There has been no serious device-related adverse events, surgical re-interventions, or evidence of device migration, expulsion, or subsidence in this study group."
More about M6 disc replacement here > >
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