The orthotic management of Familial Dysautonomia presents many challenges to the clinic team. The clinical manifestations of this disorder are many and cause accepted orthotic management regimes to be modified.
This article presents the characteristics of this disorder as well as the orthotic management of the condition as prescribed at the Hospital for Special Surgery Familial Dysautonomia Clinic. Modifications to the standard TLSO and CTLSO designs that have shown promise will be detailed. Disorders accompanied by similar clinical features also may benefit from the orthotic changes described.
Key words: orthosis, scoliosis, Familial Dysautonomia
Familial Dysautonomia, a rare autosomal recessive disorder (1) first described by Riley and Day in 1949 (2), is the most extensively described congenital sensory neuropathy (3). The disorder reduces the number of nerve cells destined to control certain sensations and autonomic functions (4). Studies suggest as few as 1 in 50 to as many as 1 in 30 Jews of Ashkenazi origin are possible carriers of the recessive gene (3,4). To date, as many as 500 cases of Familial Dysautonomia have been diagnosed around the world (5).
Orthotic management of Familial Dysautonomia-related scoliosis, which is found in 95 percent of patients with Dysautonomia over the age of 10, is poorly described in present-day literature. The goal of orthotic management of children with scoliosis is to slow and hopefully arrest the progressing scoliosis or kyphosis. The natural history of Familial Dysautonomia-related scoliosis often leads to surgical stabilization of the curve at a very young age. Delaying this surgery as long as possible is the goal of the clinic team. The purpose of this article is to describe the characteristics of Familial Dysautonomia that give rise to treatment modifications of accepted orthotic intervention. The changes made to the standard CTLSO and TLSO orthotic systems were a combined effort of the Familial Dysautonomia clinic team at the Hospital for Special Surgery in New York.
The general systemic manifestations of Familial Dysautonomia are many. Often, system abnormalities complicate one another, thereby challenging the problem-solving capabilities of surgeons and orthotists. Common findings in these children are summarized in Figure 1 .
Complications of this disease must be kept in mind-from obtaining an impression, which is routinely done under medical supervision, through final fitting and delivery. The evaluation and impression process can illicit stress-related responses, including skin blotching, reflux or vomiting crisis, breath holding and a hypertensive state when supine. Oxygen should be readily available during any procedure.
Many of the systemic disorders of Familial Dysautonomia affect orthotic treatment and design. Erratic body temperature necessitates an open orthotic design to reduce the increase in temperature caused by orthotic wear. Frequent changing of undershirts prevents skin breakdown from excessive perspiration and night sweats. Gastric reflux and dependence upon abdominal breathing are factors of major concern to physicians when considering orthotic wear.
From birth these children experience oropharyngeal incoordination, resulting in misdirected swallows that enter the lung and lead to aspiration pneumonia. If it occurs often enough, oropharyngeal incoordination can cause severe lung scarring and reduce vital capacity. Most children with Familial Dysautonomia have limited use of their intercostal muscles. They rely heavily on their abdominal muscles to accomplish respiratory excursion (5).
The impression is obtained supine in a bivalve fashion. Accurate molding of the pelvic region is essential as is the contouring of the iliac crests and anterior superior iliac spine reliefs. Measurements are taken with the child standing and preferably after eating to obtain maximum abdominal distension.
These children experience aerophagia when eating by mouth, leading to post-prandial abdominal distension. Therefore, compression of the epigastric area should be avoided. The impression can be made with fast-setting plaster bandage, using as few layers as possible to prevent overheating the skin as the plaster cures.
Adequate time should be allowed for final fitting and delivery of the finished orthosis. A TLSO design requires two to three hours of fitting time; a CTLSO orthosis requires three to six hours of fitting time. Standard orthotic checkout, as set forth in the New York University Manual (6), should be followed with the following additions:
The emotional liability associated with these patients necessitates a calm and reassuring environment for orthotic care. Using cartoon stickers on the plastic portion of the orthosis and an upbeat attitude enhance acceptance of the orthosis by both the patient and parents. The appearance of the orthosis beneath clothing is a sensitive issue with most parents of children with Familial Dysautonomia. Every effort should be made to design a system that is both functional and cosmetic.
For this patient population, conventional spinal orthotic trimlines and biomechanics do not apply. Conventional TLSO trimlines dictate an abdominal apron located at the base of the sternum, extending laterally to cover the entire abdomen. The abdomen is flattened to the height of the anterior superior iliac spines or lower, creating a force couple system to flatten the lumbar lordosis. The original TLSO Familial Dysautonomia orthosis incorporated an abdominal trimline just anterior to the axillary midline, extending inferiorly to the medial edge of the anterior superior iliac spines, down to within 50 mm (2 inches) of the pubis, thus exposing the entire chest and abdomen (see Figure 2 ). This trimline allowed virtually unrestricted breathing, access to the gastric feeding tube and distension of the abdomen after eating, thus reducing gastric reflux induced by the orthosis.
The size of this relief, however, greatly reduces the structural integrity of the orthosis. The loss of abdominal pressure compromises the ability to reduce lumbar lordosis. By restricting intra-abdominal pressure and apron height, virtually no posteriorly directed vector exists to biomechanically reduce the lumbar lordosis.
To improve the structural integrity of both the CTLSO and TLSO designs, a large buildup was incorporated on the modified positive mold to provide clearance for the distended abdomen (see Figure 3 ). The buildup often measures 25 to 50 mm (1 to 2 inches)-depending on circumference measurements taken during the initial evaluation-and extends superiorly to the umbilicus and inferiorly to within 37 mm (1 1/2 inches) of the pubis.
A channel is created by extending the crest indentations inferiorly along the medial aspect of the anterior superior iliac spines. This modification aids in controlling rotation of the pelvic girdle and, coupled with accurate and aggressive modification of the lateral and posterior aspects of the girdle, forms a structurally stable base. The girdle is trimmed to permit easy access to the gastrostomy tube (affectionately called "the button") for feeding.
To aid in erect posture, the TLSO design incorporates reinforced extensions known as "infraclavicular pads." These pads provide a posteriorly directed force to prevent forward flexion of the trunk (see Figure 4 ). No strap connects these pads, thereby allowing unrestricted breathing, which is so important to this patient population.
A greater incidence of kyphoscoliosis exists in children with Familial Dysautonomia compared to the lordoscoliosis found in idiopathic scoliosis (8). Control of kyphosis presents another challenge given the limited chest expansion, acute sensitivity to tickle (9) and the speed at which the curves become rigid.
Controlling kyphosis by using shoulder straps attached to a CTLSO has shown limited success. Using shoulder straps on certain individuals has been found to trigger abduction of the shoulder girdle, creating an area of high pressure along the glenohumeral deltopectoral area. In this case, the shoulder straps must be removed to prevent both over-stimulation of the shoulder abductors and skin breakdown. A large thick pad, placed anteriorly and attached to the posterior uprights and pelvic girdle by adjustable straps, has been substituted. Posteriorly, standard CTLSO kyphosis pads complete the force couple (see Figure 5 ).
Minor modifications to the standard CTLSO used for treating Familial Dysautonomia-related kyphosis include soft plastic-coated coverings on all uprights (children with Familial Dysautonomia tend to drool excessively), padding the neck ring and rounding the edges on the neck ring closure. Modified polyethylene plastic in a 5-mm (3/16inch) thickness is used routinely for both the TLSO and CTLSO designs. Foam lining of the girdle is avoided because it adds bulk and maintenance to the orthosis.
Conventional orthotic management dictates full-time wear at 23 hours per day, with time off for hygiene and exercise. Children with Familial Dysautonomia experience periodic vomiting episodes and do not retain the normal triggering mechanism for spontaneous breathing. Previous crises with aspiration of stomach contents may have left the lungs scarred and the child prone to respiratory infections and pulmonary congestion. Children who have experienced cyclical vomiting or are diagnosed with severe respiratory compromise should avoid using the orthosis at night. During sleep, tidal volume and oxygen saturation tend to diminish, placing children with respiratory compromise at great risk. For these reasons, a program of part-time bracing is recommended.
In a study done by Kahanowitz, Levine, et al. (10), patients were prescribed a custom-made CTLSO, which was worn for 23 hours per day for at least one year. At the end of that year, patients were reevaluated to determine if the curve had stabilized. If the curvature reduced or stabilized (reduction was maintained), a program of part-time wear was initiated. Part-time use meant wearing the orthosis after school and night or every other night during sleep. The degree of curve correction and stability determined the number of hours the orthosis would have to be worn.
The effects of part-time orthotic wear on 15 juvenile idiopathic scoliosis patients demonstrated successful control of curves less than 32 degrees at the start of orthotic management. This result shows promise for children diagnosed with Familial Dysautonomia who are orthotic candidates even though the origin of their scoliosis is not idiopathic.
In another study of adolescent idiopathic scoliosis by Green, et al. (11), 44 patients with 55 curves initially were studied wearing an orthosis for 16 hours per day. The criterion for orthotic prescription dictated curves with an apex of the eighth thoracic level or lower were fit with a Boston Brace TLSO. Those with higher levels were prescribed a CTLSO (12). The average curve degree at onset of treatment was 31 degrees with a range of 23 to 49 degrees. Strict elimination criterion in this study affords a more accurate determination of the effects of part-time orthotic wear. The study found patient compliance significantly better compared to other studies. In conclusion, the researchers found part-time wear of an orthosis can prevent progression of adolescent idiopathic scoliosis and may afford some correction, similar findings to that of Kahanowitz and Levine (13).
The modifications made to the standard CTLSO and TLSO systems have proved beneficial over the short term. The abdominal buildup has helped relieve orthosis-induced reflux, and provided greater room for abdominal distension and lung capacity. Through aggressive and careful modification of the pelvic girdle, a stable base can be achieved even though lumbar lordosis reduction and pelvic tilt may be sacrificed due to the absence of abdominal compression. Parents and guardians have expressed approval of the new design, citing reduced reflux, fewer skin breakdowns and greater overall tolerance of the orthosis by the child.
The complications associated with this disorder challenge the clinic team to be innovative in improving the orthotic design. Custom pads and strapping arrangements have been created for children who are borderline orthotic candidates in an effort to delay surgery (see Figure 6 ). Familial Dysautonomia-related scoliosis tends to progress rapidly and becomes structural early in the child's life. Therefore, it is our goal to delay surgery and permit as much trunk growth as possible, thus allowing the best possible cosmetic outcome for children with Familial Dysautonomia.
This article is dedicated to the families who attend the Dysautonomia Clinic at the Hospital for Special Surgery. In writing this article, I have become aware of the immense complexities of this disorder and have developed a deep respect for the families who care for these children.
STEPHEN W. BURKE, MD, is associate attending surgeon at the Hospital for Special Surgery and associate professor of clinical surgery (orthopedics) and pediatrics at Cornell University Medical College.
FELICIA B. AXELROD, MD, is professor of pediatrics for dysautonimia treatment and research at New York University Hospital and is a professor of neurology with permanent tenure.
DAVID B. LEVINE, MD, is an attending orthopedic surgeon at the Hospital for Special Surgery and is also professor of clinical surgery at Cornell University Medical College.
ANTHONY J. CAPPA, CPO, is supervisor of prosthetics and orthotics at the Hospital for Special Surgery-NOPCO in New York.