10 External Orthosis Management



10.1055/b-0040-177392

10 External Orthosis Management

Karen A Petronis


Abstract


The prevalence of spine fracture in the aging patient has increased. Standard fracture management protocols do not always apply to this population due to vast comorbidities including poor bone quality. Spinal segment immobilization through bracing is an option after a comprehensive analysis of the risks and benefits of the device. The decision to use an orthosis requires consideration of the fracture pattern, biomechanical properties of the device, as well as the patient’s unique anatomy, medical and cognitive state. Most importantly when the specific brace is selected the goal of the treatment should be defined, as well as a plan to limit complications and associated risks. Bracing in the elderly has limitations due to the coronal and sagittal changes of the aging spine. Each case needs to be treated uniquely as geriatric fracture treatment protocols are almost impossible to generalize to the population.





Key Points




  • The biomechanical principles of bracing guides the orthosis prescription.



  • External orthosis management in the aging population adds increased risk to the patient. This is due to the rigid design of the brace, the unique anatomy of the aging spine, and physiologic changes of aging such as skin fragility.



  • Determination of a treatment endpoint is necessary.




10.1 Summary


Use of an external orthosis in the aging patient can be an effective method to immobilize one or more spinal motion segments. Reasons to prescribe an orthosis include: fracture management, ligamentous or muscular soft tissue injury, short-term postoperative mobility restriction and to reduce pain by off loading forces from the injured area and support the soft tissue.


Understanding the biomechanical principles of each brace is the first step in the selection process. Currently available braces do not accommodate the coronal and sagittal degenerative changes that occur in the aging spine.


Following trauma, a comprehensive analysis of the risks and benefits of a particular brace, as well as a frank discussion with the patient and caregivers for a mutually agreed upon treatment decision and goals of care is vital. In the aging patient, the decision to brace is complex and not based solely on the fracture type or pattern. A thorough assessment of the potential complications may outweigh the benefits. Thus, not to brace in certain circumstances may be the best option. When an external orthosis is the mutually agreed upon decision, quick brace application allows for early mobilization and prevention of complications. Long periods of immobility are poorly tolerated by the older adult. Skin fragility should be assessed at baseline to determine whether patient-specific soft tissue features can tolerate the brace application. The risks need to be recognized with a preemptive plan for prevention. When the decision is made to brace, the goal and treatment endpoint should be determined. By keeping the endpoint in mind with critical reevaluation, one can be certain that the orthosis is performing as predicted. Additional aging comorbidities increase the risks, complicating management and medical decision making.


This chapter will provide details regarding the epidemiology, biomechanical principles of bracing, specific features of the spinal orthoses and a plan to evaluate effectiveness based on aging specific criteria.



10.2 Epidemiology


In the aging population, cervical fractures occur at a higher rate than in any other age group. Lomoschitz et al (2002) retrospectively reviewed 225 cervical spine injuries in 149 patients, who were 65 years of age or older. The population was subdivided into two groups, the “young elderly,” those 65 to 75 years of age, and the “old elderly,” those greater than 75 years of age. In the young elderly, the main cause of fracture was associated with a motor vehicle accident, as opposed to the old elderly, where the injury occurred as a result of a fall from a standing or seated position. Injury to C2 was the most common injury in both groups. 1 , 2 Guan et al (2017) described the most prevalent fracture pattern to be associated with a forced hyperextension or hyperflexion mechanism of injury. 2 Finally, there is consensus that with cervical fracture in this age group, there is an associated increase in morbidity and mortality.


Limited age-related data is reported on the epidemiology of thoracolumbar fractures. However, in the aged population, osteoporotic compression fractures are common. As noted in previous chapters, the aging population is growing rapidly, leading to increased incidence of fractures in this group. Osteoporotic compression fractures can be a great source of disability, pain, and societal burden. 3 Osteoporosis is described in further detail in chapter 3.



10.3 Biomechanical Considerations


The goal of a spinal orthosis is to immobilize a specific spinal segment or region. The principles of bracing include the ability to offload forces to the affected spinal segment and to stop or attempt to decrease movement at the level of the impairment. Complete immobilization is impossible to achieve because of the dynamics associated with the spine as well as patient specific variables.


Agabegi, et al (2010) have summarized five primary functions of a brace, each of which contributes towards biomechanical optimization, achieving optimal patient outcome. 4 These functions are to serve as a kinesthetic reminder; to distribute total surface contact; to provide three-point fixation; to supply endpoint control; and to increase pressure or fluid compression.


As a kinesthetic reminder, the brace, when applied, restricts movement and alters the position at the area of impairment, acting as a constant tactile stimulus. 5 This constant stimulus creates a learned sensation with a direct link to the spine pathology. A tighter brace provides a greater association. The presence of the brace in theory may also prompt a conscious decision to avoid high-risk behaviors or activities that would impose increased strain. Conversely, a tight brace can cause discomfort or increased pain, which can then lead to noncompliance. If the brace is poorly fit, too heavy, cumbersome or painful to wear, the compliance will be affected, leading to treatment failure.


Total surface contact is measured by the amount of square footage of the brace that is in contact with the body’s surface. This contact produces a force that is applied to the soft tissue as well as underlying bone and muscle. When there is a greater surface area contact, the applied force is less at any one point, and there is better control of motion. 4 , 5 The front and back of the brace should be conformed tightly to the body and secured to prevent movement. The lack of a secure fit leads to biomechanical failure and skin impairment associated with abnormal motion, shear, and friction.


In the aging population, this principle is important, as many patients have preexisting poor tissue perfusion, are malnourished, or are generally deconditioned. In this case, a brace with a larger surface area would be of benefit, as the force would be shared over larger areas of contact. In addition, by decreasing the pressure at any one point, skin impairment will be less likely. On the other hand, when the contact is over excessive soft tissue, as in the obese or edematous individual, the effectiveness of the brace will decrease. As described by Woodard et al, there is an inverse relationship between the thickness of the soft tissue separating the spine from the inner surface of the orthosis and the resulting effectiveness of the immobilization. 5


Three-point fixation is a principle well known in long bone fracture management and surgical stabilization. To stop motion at the fracture, immobilization needs to occur at the joints both above and below the defect. In the spine, however, this is not as easy to achieve due to the multiple levels of movable spinal segments as well as the regional variability of the cervical, thoracic and lumbar spine. The goal of this principle is to stop motion by providing two points of pressure applied ventrally, one above and one below the pathology, with the third point midway and dorsal to the site of the fracture, or near the axis of rotation for that segment. 6 The axis of rotation is a fulcrum point whereby the vertebral segment rotates. Therefore, when selecting a brace, it is important that the dorsal support is centered at or near the fractured spinal segment’s axis of rotation.


Additionally, the length of the brace also has a bearing on stability. A long brace provides a longer lever arm, which internally offers better immobilization with less force required to resist motion, translation, and rotation. 5 In other words, when the two ventral points of fixation are appropriately distanced, with the third dorsal point midway, less force is required to stop motion, as the distance from the fracture is increased. The two shorter segments provide increased resistance against bending which results in an overall decreased failure rate.


As mentioned, the fourth function of the orthosis is endpoint control. Mechanically, to manage this principle, the brace needs to be anatomically fixed at the proximal and distal end, to stop movement in the middle. Because the spine has so many moving parts, this is difficult to attain, especially in the cervical occipital and lumbar sacral regions. Standard braces have limitations in achieving a firm hold that stops motion at the head and pelvis due to the anatomical contour and surrounding vital structures. Halo immobilization devices have been described as the best method for cervical immobilization because the cephalad endpoint control is achieved by cranial pin fixation. However, even with halo fixation, endpoint control is limited as noted by the resultant abnormal movement within the cervical spine, creating a “snaking effect.” 5


Benzel describes distraction as an important component in the treatment of deformity. 6 A brace that employs distraction lengthens the spine, by pulling caudally and cephalad to the fracture. This allows the fracture ends to realign and hold an anatomical position. Unfortunately, braces are inefficient in this function because of the limitations in endpoint control. The halo vest may provide the best ability to distract.


Pelvic control using a lumbar brace is by definition unattainable unless there is control of the movement at the lumbar sacral junction and both hips. For adequate endpoint fixation in a lumbar fracture, it has been determined that there needs to be at least four to five vertebral levels immobilized distal to the unstable segment. 6 In the lumbar spine, there are not enough levels or distance to provide this degree of immobilization. Spica type designs attempt to incorporate this concept but are inefficient in that there is still unacceptable movement. In addition, with both hips immobilized, patient management is difficult due to discomfort, skin impairment, toileting concerns, and the inability to sit or ambulate.


Lastly, braces also elevate the tissue pressure surrounding the spine. When a brace is securely tightened around the chest and abdomen, it forces the soft tissue and fluids within the body to compress. Woodard et al 5 describes this mechanically as the creation of a fluid-filled cylinder, which can convert the soft tissue into a load-bearing structure. This cylinder can then circumferentially off-load the forces through the axial spine. 5 , 6 , 7 Elevating abdominal pressure results in the restriction of motion in the sagittal plane. 5 Interestingly, studies utilizing tight-fitting lumbar braces in cadaveric models do in fact demonstrate a lowering of the intradiscal pressures. 8 The mechanism of increasing tissue pressure to restrict motion is limited in its effectiveness as compared to other methods and can only be used in the thoracolumbar spine where cavity compression can occur.



10.4 Common Injury Types


The upper cervical spine is the most mobile and the most affected by injury in the aging adult. The aging spine typically demonstrates mid to distal cervical segment degeneration, stiffness, and even arthrodesis from normal wear and tear. Therefore, the upper segments are more susceptible to injury. Specific C2 fractures such as odontoid, lateral mass, or hangman can be treated conservatively in a cervical brace. Jefferson burst fractures and other injuries involving the ring of C1 are also typically deemed stable. Subaxial cervical injuries need to be individually evaluated. Many can be treated in a cervical orthosis. The stability of the joints and ligamentous structures must also be considered. Additionally, comorbidities such as diffuse idiopathic skeletal hyperostosis and osteoporosis increase the risk of fracture instability.


In the thoracic and lumbar spine, osteoporotic compression fractures are frequently encountered. Anterior wedge compression fractures are generally classified as stable. They are typically managed with hyperextension orthoses to prevent flexion, thus offloading the anterior column at the site of the fracture. 9 The brace can also provide a splinting effect, decreasing pain and muscle spasm. Based on the neurologic status, bracing is also utilized for fractures types such as a burst, Chance, or extension injury.



10.5 Treatment Options


Spinal braces are organized by the spinal region they immobilize. They can cover one region or incorporate many. The general classification includes cervical occipital, cervical, cervical thoracic, thoracic, thoracolumbar sacral, and lumbar sacral. Combinations of the different braces can be added to treat the entire spine, cervical through the sacrum. The next section will detail the various spinal orthotic devices commonly used. The goal will be to discuss the strengths and weakness associated with the five biomechanical principles as they pertain to each specific orthotic device and to discuss complications and special considerations with respect to the aging spine.



10.5.1 Cervical Orthosis


The cervical orthosis is designed to control motion through four points of fixation, two cephalad and two caudal. The cephalad points are the chin and mandible anteriorly and the occiput posteriorly. Caudally, the points are the sternum and clavicles anteriorly and the spinous process of the upper thoracic spine, usually T3 posteriorly. 4 There is very little total surface contact; thus, the forces are not dispersed over a large area, but restricted to the points of fixation. The applied force at the four points of fixation is great and can lead to skin impairment. A thorough inspection of baseline integument should be performed before brace selection. The cervical brace can successfully achieve the role of a kinesthetic reminder of the pathology due to the pressure at the fixation points and restriction of movement.


End point control in a standard cervical collar is not attainable at the cervical–cranial or cervical–thoracic junction. The mandible plays a role in point fixation; however, with speaking and, particularly, chewing, motion is realized. Distally the sternum and clavicle provide limited fixation to serve as end point control. Any movement of the arms or shoulders causes a reciprocal action of the clavicle which decreases the effectiveness of motion restriction. 4 In the cervical spine, it is impossible to increase the pressure in the soft tissue through brace compressibility. Pressure to the neck and soft tissues can result in complications associated with constriction of the vascular structures, airway and esophagus.


The cervical brace is best in restricting motion in the sagittal plane: flexion and extension. 4 , 5 It performs the worst in rotation and lateral bending due to the minimal control of the mandible. This excessive movement allowed by the collar can be realized by simply observing the aging patient change position, speak and ambulate (Fig. 10‑1).

Fig. 10.1 Biomechanical concerns of the cervical collar: lack of endpoint control and excessive lateral bending



10.5.2 Soft Cervical Collar


The soft foam collars biomechanically provide little resistance to motion; therefore, the role in fracture management is limited. 5 However, some providers feel the soft collar provides enough support when compared to a rigid device for usual activities of daily living. 10 The soft device provides surface contact. However, it provides no point of fixation or endpoint control. The collar can serve as a kinesthetic reminder of the pathology and is lightweight and easy to apply. Comfort is appreciated as the device provides support for the tissues and muscles. The soft designs have various heights; one in particular is 3 inches throughout its entire length (Fig. 10‑2). The shorter collar conforms nicely to a kyphotic, cervical spine. The length of the soft collar needs to be addressed, as many standard designs are short, making the fit too tight circumferentially. A collar that can provide up to 20 inches of available length can be fitted to the majority of patients. This is usually tolerated well in patients with a short, thick, kyphotic, or stout neck and one with excessive anterior or posterior soft tissue.

Fig. 10.2 Collar top to bottom: 3 in soft with increased length; small standard soft; medium standard soft; large standard soft.



10.5.3 Cervical Thoracic Orthosis


The cervical thoracic orthosis (CTO) provides fixation cephalad at the chin/mandible and occiput and caudally at the sternum and thoracic spinous processes/ribs. Some designs offer a head strap that adds better endpoint control. The CTO has adequate surface contact; however, compressibility is limited. Motion is best controlled in the sagittal plane with an improved restriction in lateral rotation when compared to the cervical collar. 5 The device is, however, difficult to wear due to the restrictions imposed, causing discomfort and potential for noncompliance.



10.5.4 Halo Vest


The halo vest has been credited with good endpoint control as well as superior immobilization in flexion, extension, lateral bending, and rotation. There is controversy as to which cervical fractures are best managed with halo application. Some feel that this device functions optimally with fractures of the upper cervical spine, or at the cervical–thoracic junction. 5 , 11 At the mid-cervical region, there is a concern over instability due to the muscle attachments which cause undesired flexion and extension. This instability is described as the “snaking phenomena.” 5 Theoretically, the concern for the snaking effect in the elderly may be mitigated because of the advanced degeneration at these middle segments. This age-related factor may provide protection from the abnormal snaking movement.



10.5.5 Thoracic Lumbar Sacral Orthosis


The thoracic spine is stiff, as opposed to the flexible cervical and lumbar regions. Therefore, mobility control needs to be focused on the junctional segments: the cervical thoracic and thoracolumbar regions. Based on the location of the thoracic instability, the closest junction should be immobilized. Literature suggests that injuries above T6 should be managed with a CTO. For injuries below T6, a thoracic lumbar sacral orthosis (TLSO) is recommended. The TLSO is ideal for pathology from T6 to L4. The TLSO provides cephalad points of fixation at the sternum anteriorly and thoraco-lumbar spinous processes posteriorly. Caudally, the pelvis and sacrum provide the points of fixation. Surface contact and compressibility is significant; however, endpoint control is minimal. Three-point bending principles are most times achievable, as the brace has a longer moment arm providing control in lateral bending and to a lesser extent in flexion and extension. 4



10.5.6 Thoracolumbar Hyperextension Braces


There is a second group of TLSO braces that provide hyperextension. The goal of this category is to offload the anterior vertebral column. This type of brace has been commonly used to treat anterior compression fractures commonly seen in osteoporosis. The goals are similar to those of the standard TLSO braces described above. Extension is realized through the principles of three-point bending. Using the three points of fixation—sternum and pelvis ventrally and thoracic spinous processes dorsal at or near the site of the fracture—creates a force that produces hyperextension. A typical hyperextension orthosis works best in limiting sagittal motion between T10–L2. 2 If the fracture is above T8, the ventral sternal plate should be adjusted cephalad to sit high on the sternum to gain length. Total surface contact and compressibility is limited; however, the length is generally long, providing sufficient lever arm. This brace can create skin impairment at the points of fixation due to the increased pressure and limited total surface contact. Additionally, these devises can be difficult to apply independently, which can lead to poor compliance. Working with an orthotist can help with decision-making and determination of which brace would be most effective. The standard TLSO brace can also be adjusted to provide extension if needed.



Custom Designs

Braces can be custom-molded by the orthotist from molded plastic. The specialty design can better accommodate various body habitus, maximizing total surface contact. Complex or multiple spinal fractures are best served with a unique design to accommodate the instability. A boney Chance or three-column burst fracture may require additional points of fixation. The custom braces are of higher cost and are usually heavy with little flexibility, making application more challenging in the elderly.



10.5.7 Lumbar Sacral Orthosis


The lumbar sacral orthosis (LSO) is designed to control motion from L3 to the sacrum. The LSO seems to provide the best support at L3–4 and is very limited at L4–5 and L5–S1. 5 As discussed, the endpoint control specifically at the lumbar–sacral junction is challenging, if not impossible, to attain. The pelvis contour makes it difficult to achieve point fixation, which is then even further compromised by movement at the hips. The LSO is designed to caudally fix to the anterior pelvis and posterior to the sacrum. Superiorly, there is limited ventral point fixation due to the limitations of the skeletal anatomy. Dorsally, the spinous processes are utilized, as in the TLSO. However, in the lumbar spine, the additional stabilization from the sternum is lost and the 10th, 11th, and 12th ribs provide limited cephalad fixation. The brace imposes a significant restriction in movement and discomfort which can lead to noncompliance.


Compressibility and total contact are the positive aspects of the LSO but again have limitations based on body habitus. The circumferential compression of soft tissue may be the most important part of stabilization in the lumbar spine. 5 Woodard et al (2017) concluded that the TLSO and LSO braces inadequately stabilize individual segments of the lumbar spine, but limit gross motion by altering patient activity. 5 The consequential change in the patient’s activity was thought to be the most important mechanism of action. The brace, when properly fit, can also play a role in muscle splinting, with noted modulation of pain.



10.5.8 Lumbar Corset


Given the limitations of the lumbar rigid device, a lumbar corset may be a logical consideration. There are variations in the corset designs, some with features to increase rigidity. However, based on the spinal stability of the patient, the soft elastic binder may be enough. The corset provides some compressibility and muscle support to decrease pain. This device may not provide as rigid a reminder as the LSO, but it does provide a kinetic reminder to decrease trunk motion. The binders are the least expensive, light weight, easily to apply, and can conform to altered alignment. The corset may not be appropriate for all elders but can be considered based on the patient, the pathology and the baseline level of mobility.



Benefits and Risks

The goal of bracing is to stop or minimize motion at the fracture site to allow for optimal healing. Other benefits may include a reduction in pain and possible decrease in high risk behaviors that could lead to secondary injury. The brace as a kinesthetic reminder may alter poor decisions regarding activities that can cause additional harm, such as lifting, bending or climbing.


The risks of bracing are associated with complications and poor endpoint healing results. Long-term effects of prolonged brace wear can lead to deconditioning and increased incidence of skeletal muscle atrophy in the surrounding tissue. The complications associated with bracing are numerous and are discussed in the next section. The most devastating risk of using an orthosis is a decline in neurological status. Frequent evaluation and communication with the patient and or family is needed, so that when changes occur they can be identified quickly. Another risk of bracing is that of treatment failure, as evidenced by nonunion or a poorly healed fracture. This risk is increased in the aged population due to to poor bone quality and preexisting comorbidities that affect bone healing.



10.6 Pitfalls, Complications and Avoidance



10.6.1 Cervical Orthoses


A unique characteristic in the aging cervical and thoracic spine is the alteration of the normal lordotic curve to one of kyphosis. 12 These factors make bracing difficult due to the lack of endpoint control and point fixation associated with the straightening of cervical spine. Standard orthoses are limited in their ability to accommodate the variations from patient to patient. There are a variety of “off the shelf” specialty designs that attempt to account for the stout and/or kyphotic spinal alignment. However, because of the unique patient anatomy, standard braces cannot accommodate the degree of kyphosis and/or potential scoliosis that occurs in the elder spine. Working with an orthotist can help to provide the best fit for challenging patients.


When the brace is correctly applied, it forces the cervical spine into slight extension. Caution is needed when applying the brace to assess for increased pain or discomfort at the fracture site. As discussed, in the elder there is less motion in the mid and lower cervical spine due to stiffness and potential arthrodesis. Therefore, when the brace is applied, because the distal segments are immobile, the imposed extension may occur at the mobile fracture site. This can then increase the distance between the fracture fragments with potential deleterious effect of worsening the injury. Upright X-rays in the collar can help to confirm fracture reduction and optimal positioning of the fracture fragments.


Another concern regarding the added extension associated with the cervical brace is alteration of the patient’s line of vision, limiting the awareness of their immediate environment. Aging patients, who have lost proprioception, rely on visual cues for balance and smooth locomotion. Lack of the ability to look down at their feet can lead to falls and safety concerns. Other deficits in vestibular and somatosensory functions can complicate vertical perception and balance. 4 Many times this instability requires use of a walker or other assistive device. Unfortunately, over time the patient can become dependent on the device making it a permanent adjunct even when brace free. Some acquire increased kyphosis in the thoracic and lumbar spine from leaning forward onto the walker. Consequently, this posture allows for an improved line of vision to counter the effects of the added extension. Evaluation of the patient requiring use of a walker is important to be sure first that it is needed, and then that it is used correctly, to maintain upright posture. The primary goal of the walker should be to reduce falls associated with an alteration in balance and vision.


Skin impairment is a major concern associated with the four points of fixation as well as the tissue at the lateral base of the neck and ears. Pressure from the brace is many times unnoticed due to the patient’s lack of sensation or cognition in recognition of the problem. In the acute phase of treatment, it is generally recognized that early removal of the collar decreases the potential for breakdown. Ackland et al (2007) also noted collar removal resulted in fewer ventilator days, decreased ICU stay, decreased length of stay and overall decrease in delirium and pneumonia. 13 , 14 Data reveals that 6.8% of the ICU patients in a cervical collar for more than 24 hours acquired pressure-related impairment. 15 The probability of a pressure-related skin impairment will increase by 66% for each day in the cervical brace. 14 Infection and risk of sepsis also increase due to skin impairment as well as bodily fluids that collect underneath the device. In this acute phase, based on the fracture pattern and patient condition, continuous use of the collar may not be necessary. Removing the brace when supine can improve tissue perfusion and avoid potential breakdown. If the brace cannot be removed, then use of a pillow back, posterior shell is an option available through some venders. This provides a cushion instead of point fixation at the occiput and spinous processes, which can help with skin impairment at the cost of decreasing the brace’s effectiveness. The cushioning is not without risk, as it also provides an environment conducive to moisture formation and shear.


A strategy to reduce pressure-associated complications can be achieved with a liberal brace protocol. This option includes removing the collar when supine or reclined 50°or less. Additionally, allowing the patient to shower without the brace will promote improvement in tissue viability and decrease risk of infection. Aging adults who are alert and can follow directions are able to maintain head alignment with the brace is off. Those with family or social support, who are involved in the patient’s care, will add confidence to this decision-making. A liberal protocol can also help reduce muscle deconditioning and stiffness at other cervical motion segments. Prolonged collar utilization can lead to significant loss of motion and even contracture at the fracture site as well as other cervical segments.


Swallowing difficulty while managed in a cervical collar can lead to serious complications. The brace can narrow the pharynx due to the imposed extension. Normal swallowing requires slight flexion. A chin tuck is necessary to facilitate esophageal motility for many aging adults. Choking and aspiration risk, which is a common concern in older individuals, can be made worse with the use of cervical immobilization. Difficulty swallowing leads to dehydration, malnutrition, increase risk of falls, and poor bone healing. If possible, allowing the patient to remove the collar for meals, maintaining a neutral position, may be beneficial. There are adjustments that can be made to the standard cervical brace to decrease the degree of extension by removing padding at the sternal point of fixation. Other options can be explored by collaborating with the orthotist to determine the best brace design and the degree of extension of the anterior shell. This parameter varies among vendors, but a minor alteration in the degree of extension can have significant ramifications related to swallowing function.

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Aug 1, 2020 | Posted by in NEUROSURGERY | Comments Off on 10 External Orthosis Management
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