Latest Clinical Results

1. SPINECOR PATIENTS INITIAL COHORT

At Ste-Justine Hospital patients have been treated with the SpineCor system since 1993.  For this group of consecutively treated Idiopathic Scoliosis patients the average age at the commencement of treatment was 13 years (SD : 1 year), with 176 female and 19 male subjects.  The initial major Cobb angle for the patients with a major curve of less than 30° was 23° (SD: 5°, n = 115), and for patients with a major curve of greater than 30° the Cobb angle was 36° (SD: 4°, n = 80).  For the two groups of patients the initial Risser sign was  0 for 86 and 45 patients, Risser 1 for 7 and 11 patients, Risser 2 for 12 and 7 patients, Risser 3 for 10 and 13 patients, and 2 patients with a Risser 4.  The initial cohort characteristics by curve amplitude and curve type as well as the minimum Cobb angle during treatment are presented in Table 1.

Table 1 : Initial Characteristics of Idiopathic Scoliosis Patient Population

At the last available visit there were 109 patients still under treatment with a mean treatment time of 1.5 years (SD: 1 year), and 71 have terminated treatment with a post treatment follow-up time ranging from 0 to 4.5 years.  From this cohort of 195 patients, there were 8 patients who progressed to surgery.  The patients who progressed to surgery had an initial mean Cobb angle of 34° (SD:5°), with a mean end of treatment Cobb angle of 45° (SD:6°) after 2 years (SD:1 year) of treatment.  There were also 15 patients who withdrew from treatment after a mean of 1.2 years (SD: .72 years).

2. Outcome for Idiopathic Scoliosis Patients with a Minimum 2-year Follow-up After Treatment with the SpineCor System

For the patients who have completed treatment there are 29 who had a minimum follow-up time of 2 years (mean 29 months SD : 4 months). The initial Cobb angle for this sub-cohort of patients was 29º (SD:7º), and after 3 months of treatment the mean Cobb angle was 19º (SD:11º) corresponding to an overall mean decrease of 10º  (SD: 5º)  representing a reducibility of 40%  (SD:  28%).  At the end of treatment (time=24 months; SD 9 months; Risser 3 or 4) the mean Cobb angle was 21º (SD:12º).  At this time there were 61% of the patients who maintained the initial correction obtained at three months, with 35% aggravating and 4% improving.  The mean Cobb angle at 2 years follow-up was 24º (SD:11º), where 66% maintained their end of treatment Cobb angle, 6% improved and 28% worsened. 
At 2 years follow-up there was an overall correction in reference to the patients initial state of greater than 5° for 55%  of the patients (mean: 10°; range: 6° (16%) to 15° (83%)), there was a stabilisation for 38% (mean: 2° (9%); range -3° (19%) to 5° (25%)) and 7% of the patients worsened, (mean: -8° (31%); Range: -6° (-17%) to -10° (-33%). The evolution during treatment  for the improved, stabilised and aggravated patients are presented in Figure 1.

Figure 1: 

General Treatment Trend

Table 2: Difference between each time interval during the course of treatment with the SpineCor System and during follow-up.

Table 3: Repeated measures analysis of variance for patients with a minimum follow-up of 2 years.

3. Survival Analysis of Patients Treated with the SpineCor System

A survival analysis as utilised by Nachemson  et al.,  1995 was performed on the cohort of patients treated with the SpineCor system.  The cohort of patients was divided according to the amplitude of the initial Cobb angle such that group 1 (G1) consisted of patients with a Cobb angle less than 30° and group 2 (G2) consisted of patients with a Cobb angle of greater than 30°. 

A change in the Cobb angle at the end of treatment and/or the last available visit in reference to the initial visit was utilised to identify a correction (decrease of more than 5°), a stabilisation (change of ±5°), or aggravation (increase of more than 5°).  Criteria for success was defined as a correction or stabilization of the Cobb angle, and failure as an aggravation of the Cobb angle.

 With the initial visit as a reference point a survival curve was constructed for the patients that are still under treatment in addition to the withdrawal patients.  The probability of obtaining a positive treatment effect increased as the duration of treatment increased for both groups of patients, with 95% confidence intervals of .84-1.0 and .80-.99 at 3 years of treatment in brace.   

For the patients that have completed treatment the cumulative probability of success at 4 years follow-up (combined treatment time and post treatment follow-up time) had 95% confidence intervals that were 0.82 to 1.0 and .71 to 1.0). 

A survival curve was also constructed for the patients who have completed treatment using the end of treatment status as the reference point vs the last available follow-up visit post-treatment as reference points.  The confidence intervals for the cumulative probability of success at 2 years post-treatment follow-up was 0.71- 0.98 to 0.62-1.0 for groups 1 and 2 respectively.

4. Interim Results of a Prospective Randomised Study of the Natural History of Idiopathic Scoliosis VS Treatment with The SpineCor Brace

The objective of this prospective randomised study was to compare the natural history of Idiopathic Scoliosis patients to those treated with a SpineCor brace with a Cobb angle between 15 and 30 degrees.  A cohort of 65 patients were randomly assigned to a control non-treated (n=36; age=12 years; Cobb angle:20±5 degrees) or treated group with the SpineCor  brace (n=29; age=12 years; Cobb angle : 22±5 degrees).  Inclusion criteria included an initial Cobb angle between 15 and 30 degrees, Risser 0, 1 or 2, high risk of progression (increase of Cobb angle of 5 degrees or more within the last 6 months), girl or boy and no significant malformation of the spine. Each patient underwent a comprehensive evaluation (radiological and clinical) prior to commencing the study, at 4 month intervals during treatment and follow-up.  From both groups there were 3 patients who withdrew.  For the remaining 33 control subjects there was a mean Cobb angle of 26±8 degrees  and for the treated group, 20 are still in treatment with a mean Cobb angle in brace of 15±7 degrees. The remaining 6 patients, in the treated group, have been weaned from the brace but for less than 1 year.

Table 4: Percentage of Patients Improved, Stable and Worsened at the Last Available Visit

This is the first prospective randomised study on Scoliosis patients investigating the Cobb angle between 15 and 30 degrees.  This interim evaluation reveals a strong tendency where 52 percent of the control group worsen, compared to the treated group who showed a worsening of only 5 percent.  This interim result, which shows this large difference in worsening between treated and non-treated patients, questions the logic of continuing this prospective randomised study. 

5. SpineCor Patient Treated Worldwide

The SpineCor system is currently being used at Ste-Justine Hospital as well as 52 centres world wide with nearly 725 patients in-treatment as of April 2002.   At the time of the last update of the latest available visit for these patients are presented in Figure 5, which demonstrates an improvement or stabilisation for 89% of the patients in treatment.