The efficacy of orthotic management of adolescents with idiopathic scoliosis has been debated1,2. Lonstein and Winter studied the efficacy of the Milwaukee brace in 1994, finding that braced curves progressed to surgery far less frequently than those that were only observed3. This was followed by studies of curve progression in patients using the Boston brace and other TLSO (thoracolumbosacral orthosis) designs and later by reports of night-time bracing4-8. While most reported a positive effect of bracing, others questioned its efficacy. Level-I evidence was lacking1,9,10, prompting the Scoliosis Research Society to publish guidelines for the design of studies of brace management of idiopathic scoliosis11.
What was missing from the orthotic literature, however, was an objective measurement of patients’ compliance. Morton et al. documented that patients and families over-report hours of brace wear compared with data provided by in-brace temperature monitors12. In 2010, Katz et al. demonstrated that the majority of the patients in their prospective study had not worn their orthosis even half the time that had been prescribed13. Yet, there was a highly significant positive correlation between the hours of brace wear and the likelihood of the curve not progressing. A threshold of twelve hours of daily wear was established on the basis of compliance data collected using temperature monitors. Unfortunately, very few wore their brace even twelve hours per day, rendering the study underpowered.
The BRAIST (Bracing in Adolescent Idiopathic Scoliosis Trial) was published in 2013, lending evidence to the efficacy of bracing of idiopathic curves between 20° and 40°14. The BRAIST group used temperature monitoring to collect compliance data for the first six months of brace use by 116 patients and found an average of 12.1 hours of daily brace wear. Hours of wear were statistically related to a decreased likelihood of surgery (p < 0.001).
The report by Katz et al.13 and the BRAIST14 both established that compliance with brace wear is frequently poor and that increased hours of brace wear correlate with a more successful outcome. The question arose: can compliance be improved? We hypothesized that patients would be more likely to wear their brace if they knew that compliance was being monitored. Furthermore, we proposed that brace wear could be increased by providing counseling using actual downloaded compliance data. Finally, we hypothesized that increased brace use would decrease the prevalence of curve progression and surgical intervention. The Hawthorne principle states that subjects modify their behavior based on knowledge that they are being studied15. We hypothesized that patients would be less likely to “cheat” if they knew that they would be discovered.
Materials and Methods
Patients with idiopathic scoliosis were invited to participate in the study at the time that their initial TLSO-style brace was prescribed. This trial was registered at ClinicalTrials.gov (NCT02412137).
Inclusion criteria were a curve magnitude between 25° and 45°; Risser stage 0, 1, or 2; and, if the patient was female, less than one year post menarche. After the study was approved by our institutional review board, parents provided informed consent for the temperature in their child’s brace to be monitored. Thermochron iButtons (Maxim Integrated) were recessed into the front of the orthosis and covered with a thin layer of tape16,17. The sensors logged temperature every fifteen minutes for a duration of three months each. Six months of data could be stored between visits.
The patients were divided into two groups on the basis of their treating physician, who was randomly assigned to them on referral. We did not divide patients randomly within treatment teams as we did not want the two groups discussing the study, sensors, or counseling while waiting for clinic visits together in the waiting room. The treating physicians were assigned to either counsel or not counsel their patients with use of the compliance data obtained by the sensors by randomly drawing from a bag. Four orthopaedists were assigned to the counseling group and four, to a blinded noncounseling limb. Each physician worked with his/her own orthotist exclusively. All orthoses were made in the hospital’s orthotics department.
Patients in the counseled group were told that sensors embedded into their brace would monitor the temperature of the brace and provide feedback regarding hours of brace use. At each clinic visit, data from their sensors were downloaded into a computer and a brace-use report was printed using a custom-designed computer program (Fig. 1). The sensors were then rebooted and remounted for further data collection. The orthotist and orthopaedic surgeon shared the report with the patient and parents, and counseled them regarding the hours of wear.
The parents and patients in the noncounseled group were aware of the temperature sensors in the brace but were not informed that they measured compliance. Their orthotist and physician did not have access to the downloaded compliance data. The treating orthotist could view a few lines of raw temperature data for the purpose of establishing the functionality of the sensors, but the computer did not show the processed results. As each day is represented by 92 lines of data, manually estimating wear from that limited data is not practical. The patients did not receive a brace-wear report at any time. Routine encouragement regarding brace wear was given, but no compliance data were known at any time.
In the rare instances that more than six months elapsed between visits, only the actual downloaded data (which could be collected for only six months at a time) was used. When patients discontinued using their brace prematurely, the average daily wear was entered as a zero from the point at which the data were no longer collected to the time at which the patient was told to discontinue using the brace by the surgeon.
Radiographs were measured by a single observer (L.A.K.) at the time that the brace was prescribed, when the first radiograph was made with the patient wearing the brace, when use of the brace was discontinued, and at the time of final follow-up or preoperatively. The Risser sign and the status of the triradiate cartilage were noted on each radiograph. Curve progression was defined as an increase in curve magnitude of ≥6°. Progression to a magnitude requiring surgery was defined as either a curve magnitude of ≥50° or if spinal fusion was performed.
The average daily hours of wear for the entire time of brace treatment were compared between groups. The prevalence of curve progression and progression to a magnitude requiring surgery were also compared between the two groups. The average hours of brace wear were then compared among patients whose curve did not progress ≥6°, those with curve progression of ≥6°, and those with curve progression to a magnitude requiring surgery.
Statistical analysis was performed comparing curve magnitude between the counseled and noncounseled groups, hours of brace wear between the counseled and noncounseled groups, and brace wear between patients whose curve did not progress to a magnitude requiring surgery and those whose did. Continuous variables were first examined for normality, and nonparametric tests such as the Mann-Whitney test were considered. A p value of <0.05 indicates significance.
Source of Funding
There was no external source of funding for this study.
Two hundred and twenty-two patients were enrolled from 2008 through 2013. Seven patients were subsequently found to be ineligible for the following reasons: four were seen to have a nonidiopathic curve on preoperative magnetic resonance imaging, one did not have sensors embedded into her brace, one lost her brace, and one elected to seek vertebral body stapling elsewhere. Five patients (two counseled and three not counseled with use of the sensor data) withdrew from the study. This left 210 patients—189 girls and twenty-one boys—in the study group. Twenty-five patients (sixteen counseled and nine not counseled) had not returned for follow-up for more than one year and thus were considered lost to follow-up. Two patients underwent spinal fusion without curve progression and were therefore excluded from analysis. Twelve patients (five counseled and seven not counseled) were still wearing the orthosis at the time of the study and thus complete data were not available. One hundred and seventy-one patients had completed brace treatment and form the study group for this report. Their average age at the initiation of bracing was 12.3 years (range, 10.2 to 16.0 years).
Of the 171 patients who had completed brace treatment, ninety-three (eighty-two girls [88%] and eleven boys) were in the counseled group—i.e., they received counseling regarding compliance based on the sensor data at each visit. The noncounseled group consisted of seventy-two girls (92%) and six boys who received the usual advice regarding compliance, but neither they nor their health-care providers received objective compliance data derived from the sensors. There was no significant difference between the groups with respect to the curve magnitude at either brace initiation (33.2° for the counseled group versus 33.9° for the noncounseled group, p = 0.21) or the initial in-brace correction (p = 0.13). In the counseled group, sixty-two patients (67%) were at Risser stage 0; eighteen (19%), Risser stage 1; and thirteen (14%), Risser stage 2. In the noncounseled group, sixty (77%) were at Risser stage 0; twelve (15%), Risser stage 1; and six (8%), Risser stage 2.
There was a significant difference in the average daily hours of brace wear throughout the entire course of treatment between groups. Daily brace wear during the initial 180 days following delivery of the orthosis averaged 15.0 hours in the counseled group and 12.5 hours in the noncounseled group (p = 0.0095). Counseled patients who completed bracing averaged 13.8 hours per day of orthotic wear throughout the entire course of bracing, compared with 10.8 hours per day for the patients who did not receive compliance reports (p = 0.002).
The curve did not progress ≥6° between brace prescription and brace termination in fifty-five (59%) of the ninety-three patients in the counseled group and thirty-six (46%) of the seventy-eight in the noncounseled group (Fig. 2). Patients whose curve did not progress to a magnitude requiring surgery wore the brace for an average of 14.1 hours daily in the counseled group and 11.6 hours daily in the noncounseled group (p = 0.034).
Twenty-three (25%) of the ninety-three patients in the counseled group had progression to ≥50° or to surgery whereas twenty-eight (36%) of the seventy-eight patients in the noncounseled group had progression to ≥50° or to surgery (Fig. 2). This trend did not reach statistical significance (p = 0.112). One additional patient in each group underwent surgery without documented curve progression of ≥6° and therefore these patients were excluded from analysis. Daily brace wear averaged 12.6 hours for the patients in the counseled group whose curve progressed to a magnitude requiring surgery and 9.6 hours for those in the noncounseled group whose curve progressed to a magnitude requiring surgery. This difference was not significant (p = 0.069).
Finally, there was a significant difference in daily hours of brace wear among all patients (in both groups) who did not have curve progression of ≥6°, those who did not have curve progression to a magnitude requiring surgery, and those for whom surgery was recommended or performed. The duration of daily brace wear averaged 14.4 hours for the ninety-one children who did not have progression of ≥6°, 13.1 hours for the 120 who did not have progression to a magnitude requiring surgery (including those who had <6° of progression), and 11.0 hours for the fifty-one who had progression to a magnitude requiring surgery. The difference in measured brace wear between the patients who did not have progression to a magnitude requiring surgery and those who did was significant (p = 0.029), and the difference in brace wear between the patients who did not have ≥6° of progression and those who did was highly significant (p < 0.0001).
Risser stage-0 patients wore their brace an average of 11.9 hours daily; Risser stage-1 patients, 13.4 hours; and Risser stage-2 patients, 14.2 hours. The difference in wear between the Risser stage-0 group and the combined Risser stage-1 and stage-2 groups was not significant (p = 0.11). The patients with immature Risser signs were most at risk for curve progression to a magnitude requiring surgery. Forty-nine (40%) of 122 Risser stage-0 patients who completed bracing had curve progression to a magnitude requiring surgery, compared with two (7%) of the thirty Risser stage-1 patients and none of the nineteen Risser stage-2 patients.
Overall, only 102 (60%) of the 171 patients wore their brace twelve or more hours daily. Of these 102 patients, twenty-six (25%) required surgery. The remaining sixty-nine patients wore their brace an average of less than twelve hours per day, and twenty-five (36%) of these patients required surgery. Sixty-three (68%) of the ninety-three counseled patients wore their brace at least twelve hours daily, whereas just thirty-nine (50%) of the seventy-eight noncounseled patients averaged at least twelve hours per day. Sixty-six of the 171 patients (39% overall, 50% of the counseled group, and 26% of the noncounseled group) wore their brace for at least fifteen hours daily, and sixteen (24%) of the sixty-six required surgery. No Risser stage-1 patient who wore a brace for at least twelve hours daily (n = 17) required surgery.
Compliance counseling is not new in the field of orthotic treatment of scoliosis. Studies have been published after use of thermosensitive sensors in the braces of small numbers of children16-21, with many demonstrating a relationship between brace use and curve stabilization22. Miller et al. shared compliance information with ten adolescents and withheld compliance data from eleven adolescents over a time period of fourteen weeks after the initiation of bracing23. Their informed patients wore their brace an average of 5.24 hours more daily than their blinded patients. They did not follow their patients throughout the entire course of bracing, however.
The results from our study corroborate the conclusion of Katz et al. that there is a significant difference in average daily brace use between patients who have curve progression to a magnitude requiring surgery and those who do not13. These data lend support to the principle that orthotic management of adolescent idiopathic scoliosis is beneficial. The relationship between hours of brace wear and success in preventing progression to a magnitude requiring surgery was highly significant, as it was in the BRAIST study14.
Furthermore, we can conclude from the comparison of the counseled and noncounseled groups that sharing compliance monitoring data with the patient is a useful tool for improving brace use. The patients who received brace-compliance reports wore their brace for more hours daily than did those who did not receive such reports. In fact, the counseled patients in our study wore their brace for far more hours daily than did the patients in the 2010 study by Katz et al.13, who were treated by the same orthopaedic surgeons and orthotists. Only thirteen (17%) of seventy-five Risser stage-0 patients in the 2010 study wore their orthosis a minimum of twelve hours per day13. Using a similar algorithm, we found that forty-three (69%) of sixty-two counseled Risser stage-0 patients wore their brace for at least twelve hours daily. Clearly, counseling using objective compliance data increases brace use. Surprisingly, twenty-eight (47%) of the sixty Risser stage-0 patients in our noncounseled group wore their brace at least twelve hours daily. We believe that the increased compliance in this study resulted from treating orthopaedic surgeons better informing patients about the importance of compliance at the onset of brace wear, regardless of whether they received the sensor data or not. On the basis of the work of Katz et al., each patient was strongly encouraged to wear the brace as prescribed. While the data from that study and ours show that very few children wear the brace exactly as prescribed, we found that compliance has improved, most notably when patients receive brace-compliance reports throughout their care.
Unfortunately, some patients will not wear a spinal orthosis as directed. The sensors revealed that thirty-six of the 171 patients wore their brace less than eight hours per day. Only 14% of the counseled group wore their brace less than eight hours daily, or essentially refused to wear the brace, compared with 31% of the noncounseled group. It appears the Hawthorne effect was influential in modifying the behavior of these adolescents. Although some patients were found to be completely noncompliant, it could be proposed that use of monitors for such children may be of economic benefit. If the medical team was aware that the twenty-four noncounseled patients (representing 31% of the noncounseled group) were not wearing their orthosis, additional orthotic appointments and brace modifications/replacements could have been avoided, saving health-care dollars.
This study defined compliance in terms of the number of hours the spinal orthosis was worn daily. How tightly the brace was worn was not monitored. Therefore, the quantity but not the quality of brace wear was measured. The effect of brace strap tension on the success of orthotic control of scoliosis is unknown at this time.
There was concern that providing a brace-compliance report and counseling at each visit could increase the stress that patients already experience during brace treatment. Studies have shown that teenagers undergoing brace treatment for scoliosis may experience greater psychological stress than normal24. Five subjects dropped out of the study. Only two were in the counseling group; the other three were blinded to their compliance data. While the counseled patients may have felt an element of confrontation from receiving brace-compliance reports, we found it interesting that the noncounseled patients dropped out, especially as one requested switching to the counseled group after discovering the role of the sensors. We reviewed the records of the sixteen patients in the counseled group who had been lost to follow-up before completion of brace treatment to see if they stopped attending the clinic as a response to brace counseling. We found that eleven of the patients were lost to follow-up either immediately after receiving their orthosis or after their first in-brace visit. Therefore, only five patients stopped coming to the clinic after receiving counseling regarding their compliance or lack thereof. While we are sensitive to the emotional needs of this patient population, we believe that the brace-compliance report can be shared with the patient and family in a way that is a helpful, and not punitive, addition to the clinic visit.
In conclusion, compliance counseling based on sensor data increased brace use by an average of 3.2 hours daily and decreased the number of patients requiring surgery by 11%. Children who did not need surgery wore their brace 2.1 hours more per day on average. If compliance monitoring and counseling can increase daily wear by 3.0 hours, perhaps some children who receive such counseling throughout their orthotic treatment will be successfully treated with the brace and avoid spinal surgery. The monitors were inexpensive and easily inserted into the orthosis. We believe that compliance monitoring/counseling should become part of the clinical care of patients of any age wearing an orthosis for idiopathic scoliosis, as monitoring combined with counseling favorably influences the outcome of bracing of adolescents with idiopathic scoliosis.
NOTE: The authors acknowledge the work of ChanHee Jo, PhD, for statistical analysis and the orthopaedic and orthotic departments for participation in patient counseling.
Investigation performed at the Texas Scottish Rite Hospital for Children, Dallas, Texas
A commentary by Kent Alan Reinker, MD, is linked to the online version of this article at jbjs.org.
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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