Orthotic management of spinal disorders dates back at least to the Middle Ages.
Some of the concepts underlying those primitive devices, notably three-point forces, remain valid today. Fabrication materials have progressed from metal and leather to light weight thermoplastics allowing many new designs and a new level of comfort for the patient.
Spinal bracing utilises these primary objectives. Controlling back pain by limiting motion and unloading discs, vertebrae and other spinal structures by compressing the abdomen. Stabilising weak or injured structures by immobilising the spine. Providing three-point force systems to provide correction or prevent progression of a deformity.
Braces are used to help prevent the curve getting worse. They do not usually improve the degree of curvature. They work on the same principle as staking a young plant to prevent it bending while it is still young and growing. The surgeon may prescribe a brace if a child's curve is below 40º and is likely to get worse, and in very young children if he thinks that it will be effective. For a brace to work it must be well designed and fitted, it must be worn, and there must be good patient co-operation. Recent research has shown that if patients are compliant, which means that they wear their brace for at least 80% of the time that they should, bracing can be successful in preventing deterioration of a curvature. Sometimes braces can be unsightly and restrict activities - eg, contact sports should not be played because of possible injury to other players.
Clothes that hide the brace and seam free vests to wera beneath it may help to overcome some reservations. Skilled and specially trained technicians make the braces. Their skill is most important since if a brace does not fit properly it will not be worn, and that could be detrimental to the progression of the curve. Usually the brace is worn for 20-22 hours a day, and should be taken off only for swimming and bathing. There are several kinds of brace and the type prescribed depends on the type of scoliosis.
The segment of the body that is being controlled generally classifies spinal bracing terminology. Sacroiliac (SIO), lumbosacral (LSO), thoracolumbosacral (TLSO), cervicothoracolumbosacral (CTLSO), cervical (CO) and cervicothoracic (CTO) orthoses. Control is described in terms of spinal flexion, extension, rotation and lateral bending.
Spinal orthoses are categorised as flexible, rigid or semi-rigid. Flexible orthoses or corsets are prescribed for relief of low back pain associated with degenerative disc disorders, trauma or postural deformities. Corsets are typically made of cotton and nylon materials. Corsets are used to de-weight spinal structures by increasing abdominal compression. Rigid stays and inserts can be added to restrict motion and act as a postural reminder. Most corsets are pre-fabricated and custom fit and modified to the patients specific needs.
Rigid orthoses are commonly custom fabricated and provide the most support to the area being treated. A body jacket or TLSO controls motion in all planes. Depending on the goals of the TLSO, design can be modified accordingly. A two piece front and back design is commonly used post operatively for ease of application while a front or back opening single piece design is commonly utilized when treating scoliosis. Velcro™ straps are most commonly used to fasten the closure on all orthoses today.
When indicated, orthotic management of the spine can be very successful. When orthotic care is needed, it is important that the health care professional providing these services is properly credentialed. An ABC certified orthotist has the highest minimum credentials in this specialized field. An ABC certified practitioner will use the prefix (CO) certified orthotist or (CPO) certified prosthetist/orthotist next to their name.
The use of a thoracolumbar orthosis (TLSO) is the only nonsurgical method of controlling scoliosis progression that has any evidence of success. The original Milwaukee brace, designed by Walter Blount in the 1940s, was used for a variety of indications. Since that time, the indications for brace treatment of AIS have been narrowed, and current recommendations are to use a scoliosis brace to prevent progression of moderate curves only during growth. The exact upper and lower limits of curve magnitude that are appropriate for brace usage remain debated; however, the Scoliosis Research Society has published the following guidelines:
The goal of brace treatment is to limit further curve progression, ideally keeping the Scoliosis from reaching surgical indications. Although curve severity is reduced after appropriate brace fitting, this correction primarily occurs only when the brace is worn. In most patients, correction of the deformity is not maintained when the brace is discontinued. Thus, if a patient presents with a clinical deformity and scoliosis that suggests a need for surgical treatment, the situation is not likely to change even if a brace if worn during the period of remaining growth.
Currently, methods for nonsurgical reversal of a scoliotic curvature do not exist. For the patient and family to be offered a brace with the best outcome only being prevention of further progression is often a difficult and frustrating circumstance.
The decision to initiate brace treatment, even in the ideal patient (eg, Riiser 0 to 1 girl with a 35º thoracic scoliosis), is never simple. The psychological stresses are substantial, and for some, make this form of treatment impractical. The Milwaukee brace has largely been replaced with less obvious underarm designs; however, these braces remain uncomfortable and hot, and they restrict mobility. These limitations have spawned a variety of brace designs to address these issues.
The most notable is the Charleston nighttime bending brace. The brace hypercorrects the deformity by bending the trunk toward the convex side. The benefit to the patient is a reduced requirement for time in the orthosis. The CHarleston brace is prescribed only for nighttime wear as opposed to the 22 to 23 hours a day that are standard with underarm TLSOs. Other new designs that have little evidence of efficacy allow mobility within the brace while maintaining corrective forces through elastic and spring elements.
Brace correction is believed to occur by constant molding of the trunk and spine during growth. Full time bracing was, therefore, originally suggested and remains the method of choice at several centres. However, full time brace wear is difficult. Therefore, brace wearing schedules have been modified, reducing the time in the brace to 15 to 16 hours per day. This gives the child the opportunity to go to school without the brace. However, in this scenario much of the brace wear occurs at night when the biomechanical deforming forces are the least (supine compared to standing), and, therefore, the efficacy may be reduced.
In addition, monitoring studies have suggested that patients wear their orthoses much less than prescribed (approx 16 hours per day if prescribed 23 hours per day and 10 hours per day if prescribed 16 hours per day). A dose dependent relationship between the time per day in the brace and success in preventing curve profression was found in a meta analysis of the literature and suggest that the more time the patient spends in the brace the less likely the curve will progress.
Although brace treatment was deemed successful for many years, only recently have controlled treatment trials been completed. Prior studies reporting high rates of success were often composed of many patients at low risk of progression. Lonstein and Winter evaluated 1,020 patients treated with a Milwaukee brace. Patients with a risk progression and presenting with an initial curve between 20º and 29º were found to have less progression when treated with the brace than described in the natural history data. The Scoliosis Research Society sponsored a study that compared the results of observation, braing, and electrical stimulation. Although this study metholody was criticised, many centres continue to advise brace treatments in patients with AIS who present with substantial growth remaining.
The effect of brace design on outcome is difficult to compare because most studies do not use the same inclusion criteria, and indications for brace vary depending the type and localisation of the curve. In two recent studies, however, the underarm brace design worn full time was found to be more effective both at preventing progression and preventing further surgery than the Charleston nighttime bending brace design. However, for single lumbar and thoracolumbar curves, results from the Charleston nighttime brace equalled results from the Boston Brace.
The decision to include bracing in the treatment algorithm is debated by some; however, if it is to have any chance of success, a coordinated effort must be made among the treating physician, the patient, and his or her family as well as an orthotist with a strong interest in scoliosis treatment. Careful fitting and continued adjustment of the brace optimise curve correction while intermittent radiographs (every 4 to 6 months) are used to monitor for progression. This lack of progression, however, cannot be achieved without the patient's cooperation in conforming to the brace wearing schedule.