With an incidence of approximately one per 1,000 births in the United States, spina bifida is the most common birth defect that results in permanent disability. Management can be complex and challenging for the orthotist. Achieving an adequate level of orthotic intervention without overbracing is a delicate balancing act and requires an individualized and multifactorial approach. What are the goals of treatment and how are orthotists meeting the needs of this patient population?
|Four year-old Jesse visits the outpatient clinic.|
|K. Goodstein, Shriners Hospitals|
Similar in many aspects to a spinal cord injury, spina bifida is a nonprogressive congenital neuromuscular pathology, and as with spinal cord injuries, the level of the neural tube defect defines the level of physical disability the patient will have. The higher the level of the defect, the greater will be the degree of disability, so to a large extent, the degree of disability as well as what the patient’s predicted capabilities will be dictates the role the orthotist will play in a particular patient’s management.
Patients with a lower level of defect will have better function and require less intervention, while patients with higher levels of defect will require more intervention. Most patients with higher level defects will receive care from a multidisciplinary clinical team. Such teams typically include orthotists, physical and occupational therapists, orthopedists, pediatricians, urologists and neurologists, as well as ancillary support staff.
According to Ron Gingras, CPO, director of the Tampa Shriners Hospital orthotics and prosthetics department, early goals of orthotic treatment include preventing deformity or correcting flexible deformities, promoting mobility, pre-positioning of the feet to provide correct alignment in anticipation for weight bearing, and nighttime bracing to prevent progression and reduction of knee flexion contractures. These early preventative measures can help to minimize bracing later, which could result in improved ambulation, hygiene and personal care.
For infants with spina bifida, paralleling the developmental milestones that healthy children reach is essential for normal development. These milestones include independent hands free sitting, standing to allow the child to be at eye level of his peers and to encourage exploration of the child’s environment. Finally, encouraging independent ambulating as close to the appropriate age as possible is also important to the child’s development.
New spina bifida patients initially are assessed at approximately age six to eight months to determine their motor function and predict their functional level later in life to begin formulating a treatment plan. Usually the first type of orthosis a child with spina bifida is fitted with is an ankle-foot orthosis (AFO) to prevent plantarflexion contractures and other angular deformities. The AFO provides stability around the ankle and foot to enable patients to stand. AFOs also are frequently used to maintain a surgical correction. The AFO is designed and fit for a patient’s particular needs, and many different trimlines can be used, said Gary Trexler, CO, LO, clinical orthotist and clinical assistant professor at the University of Oklahoma.
|Jesse is getting ready for his x-ray as Cheryl Haddy, x-ray technician helps remove his braces.|
|K. Goodstein, Shriners Hospitals|
The most common type of AFO used in patients with spina bifida is a solid AFO, followed by a floor-reaction AFO. However, Marc Kaufman, CPO, of Atlanta Prosthetics and Orthotics, said the majority of misused or improperly used orthoses for children with spina bifida are solid AFOs when a floor-reaction AFO would actually be the optimal orthosis to give adequate push-off or stabilization of the knee mechanism throughout stance phase. Incorporating external posts stabilizes the foot and ankle and can have a significant effect on more proximal segments, especially if genu valgum or genu varum is involved.
In addition to providing stability to the foot and ankle complex, AFOs also act as protective devices. “When I first started working with these children who have no feeling in their ankles and feet, for the most part, it scared me to death to be working with a child who couldn’t feel you putting on plastic around their ankles and feet, especially these bony areas,” said Trexler. “Over the years, after going to spina bifida camps and seeing these kids throughout the day, it dawned on me that AFOs are more of a protective device than they are anything else. If you watch these children, they transfer from a bed to a wheelchair and just plop down into the wheelchair, and their legs go flying and bang on the uprights of the wheelchair and the footrest. The AFOs actually protect the kids from fractures and pressure sores.”
When children with spina bifida are approximately one year old, they are then fit with a standing frame, said Dan Griner, CPO, assistant director of orthotics and prosthetics at Shriners Hospital for Children in Tampa. “One of the biggest factors in the early intervention in standing is that these children don’t have to use their upper extremities to support themselves so they can do some hands-free playing and other normal developmental activities.”
Developing mobility at an early age is important for a child’s psychological development as well as his or her physical development, said Craig Kraft, BS, IT, director of seating at Shriners Hospital for Children in Tampa. In addition, achieving mobility at a very young age is important so that the children are not dependent on their mother or caregiver to carry or move them around.
As patients with spina bifida reach the age of two years, if they are deemed to be an eventual ambulator or at least a therapeutic ambulator, they may move into a swivel walker. Then, depending on how much stability patients need as well as their cognitive ability, upper extremity strength and level of defect, patients will advance to a knee-ankle-foot orthosis (KAFO), a hip-knee-ankle-foot orthosis (HKAFO) or a reciprocating gait orthosis (RGO).
|Tyler visits Shriners Hospitals outpatient clinic.|
|K. Goodstein, Shriners Hospitals|
“With HKAFOs, patients have enough muscular ability to advance and extend their legs at the hip independently, so they inherently can do that, but they don’t have the ability to maintain an upright position due to the deficit of innervation in their lower extremities,” said Janet Marshall, CPO, of Shriners Hospital for Children in Tampa.
For patients with hip flexion contractures, the traditional metal pelvic band or butterfly pelvic band used with HKAFOs can be difficult to adjust. In such patients, a HKAFO with a custom pelvic lumbosacral section dramatically affects stabilization.
“I use a lot of HKAFOs, and just about all of them include a custom pelvic section of molded plastic. I do a different casting technique where I basically cast the whole body up to the torso,” said Kaufman.
He then has patients stand after the impression is set with the pelvis section included, and checks the weight lines with heel wedges, which helps with the modification and fabrication process.
For children who do not have the muscular ability to advance and extend their legs at the hip, which is the case with many patients with spina bifida, RGOs provide a mechanism to shift the weight and advance the legs with the use of a walker, thereby achieving a reciprocating gait, said Marshall.
Isocentric RGOs frequently are used and seem to work best because of their rigid frame and low coefficient of drag, said Harry Brandt, Jr., BOCO, RTO, manager of orthotics and prosthetics at Shriners Hospital for Children in Northern California.
“We use lateral uprights on the RGO, with AFOs that are trimmed high around the condyles which includes a varus or valgus pull-over strap to provide some medial and/or lateral knee control. This combination allows patients to easily don and doff the device for ambulation. We can make an ambulating device or an RGO with a lot less bulk because we’re using a stronger pelvic section,” he said.
Another concern for children with spina bifida is the development of scoliosis or possible need for corrective spine surgery as they get older, hence, thoracolumbosacral orthoses (TLSOs) frequently are incorporated into their orthotic treatment for external support. The type of TLSO Brandt prefers is Spinal Technology’s Flex Foam, which has an exterior plastic shell and an interior consisting of two types of foams of different density that are formed together. “It’s a nice jacket because it provides enough rigidity to hold a flexible spine, yet the edges are soft so you don’t create pressure problems, thereby helping to prevent skin breakdown,” said Brandt.
|Matthew is being assessed by clinicians, orthotists and therapists. His MAFOs are being made for him. Matthew is 2 years old.|
|B. O’Doherty, Shriners Hospitals|
Although orthotists and prothetists tend to be a little skeptical at first of new orthoses, refinements have been made over time to some orthoses used in the management of spina bifida. A recent refinement to the RGO includes a specialized hip joint available for children with spina bifida, said Griner. It allows abduction in the orthosis at the hip and can be locked for ambulation, but permits catheterization without removing the orthosis.
Another change to some of the orthoses available follows the adage of less is more, with less hardware being placed on devices.
“We’re paying much more attention to what we can leave out of the orthotic design that is not necessary, rather than applying cookbook bracing techniques,” said Gingras. “I think we’re fine tuning these devices so that they’re easier to use for the important issues of independence regarding mobility, ambulating, hygiene and personal care.”
Of course, during the past 10 years, technological innovations and the implementation of new materials and new designs have influenced orthoses in general, particularly lower extremity orthoses, said Chris Hovorka, MS, CPO, clinical coordinator for the master’s of science in prosthetics and orthotics program at Georgia Institute of Technology’s School of Applied Physiology.
“The profession of orthotics and prosthetics has borrowed from the aerospace and biomedical engineering professions, which have experimented with ultra-light materials that have a high strength-to-weight ratio. In other words, one aim in device design has been to integrate a super light material that is very strong, which has a lot of benefits. Particularly in lower extremity orthoses, when you are trying to control joint motion with a lightweight material, it is desirable that it withstand significant repetitive loading and still provide the biomechanical controls.”
Management Beyond Childhood
Children with spina bifida require periodic follow-up for adjustment of orthoses and assessment of pressure areas. Ideally, patients with spina bifida who continue to use orthoses should undergo follow up throughout their lifetime because they usually possess deformities, physical deficits and neuropathies that will be with them for their lifetime, said Hovorka.
As patients with spina bifida approach their teenage years, those with higher level defects tend to use their orthoses less frequently and eventually discard them altogether. As the children grow, the orthoses also must be made larger and more difficult to don and doff, which becomes a big issue, said Marshall.
Ultimately, the decision to stop using orthoses is overwhelmingly the child’s decision, said Trexler.
“As they get a little older, they take over and say, ‘It’s quicker for me to get around in this wheelchair, the heck with the rest of that stuff. It’s too much to wear around, it’s too hard to put on, it’s too heavy to wear,’” he said.
However, by the time children stop using their orthoses — often at the age of 10 or 11 — “the RGO has basically done its job. It has allowed them to ambulate and helped with bone and organ growth as well as weight management,” said Brandt.
Developmentally, the orthoses have allowed children with spina bifida to parallel their peers and attend school and play with them. In addition, when these children get to their teenage years, they are in much better orthopedic condition because of the bracing, said Kraft.
Finally, as Gingras noted, it should be remembered that orthotic intervention and treatment is only one of the cogs in the wheel of care necessary in the treatment of children with spina bifida.
Orthotists need to work very closely with other team members to assure the coordination of their collective efforts will lead to the successful fulfillment of the goals that are set forth for every individual child.
For more information:
- Supan TJ, Hovorka CF. A review of thermoplastic ankle-foot orthoses adjustments/replacements in young cerebral palsy and spina bifida patients. Journal of Prosthetics and Orthotics. 1995; 7(1):15-22. Available online at http://www.oandp.org/jpo/library/1995_01_015.asp?searchquery=Hovorka