Cervical Management of the Infant with Larsen Syndrome

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By Kara Davis, CPO, LPO, MS

Introduction

Kara Davis, CPO, LPO, MS

Larsen Syndrome is a congenital, hereditary condition that primarily affects the musculoskeletal system. It presents with various clinical manifestations and levels of severity.1 Children with highly involved Larsen Syndrome may not survive past infancy, particularly if life-threatening symptoms are not well managed with advanced orthopedic care.9 However, the central nervous system develops normally so cognitive function is intact, and many patients' symptoms may be orthopedically managed.8

Physical differences such as dislocation and/or hypermobility of the joints, particularly the knees, elbows, and hips, often exist from birth. The forehead can appear quite prominent and the eyes wide set with a flattened nasal bridge, and a cleft palate may be present.1,7 The feet can appear in an equinovarus or equinovalgus presentation.7 A characteristic
accessory calcaneal apophysis is also a classic finding in patients with Larsen Syndrome.5

While the physical features may prompt further investigation into a formal diagnosis of Larsen Syndrome, it is some of the unseen symptoms that are the most important to detect. For example, breathing difficulties and abnormal spinal curvatures may not be readily obvious, but the infant should be carefully evaluated and monitored to determine if such abnormalities exist. Imaging of the cervical spine should be ordered to determine whether hyperkyphosis is present.1,2

Cervical Spine Hyperkyphosis

Hyperkyphosis of the cervical spine in infants can have dramatic effects if left untreated. One of the most serious effects is spinal cord impingement, which can cause loss of neurologic function, possibly resulting in the loss of muscle and respiratory function, delayed motor skills, and even loss of life.6,13 In severe cases of kyphosis, it may be necessary for even very young infants to undergo surgery, although orthotic interventions can sometimes be used as a temporary solution until the infant's spine is more developed.

If spinal fusion surgery has been performed, orthotic interventions are often used for post-operative stabilization and immobilization.12 The bones in the cervical spine are so tiny and frail that orthotic stabilization is needed to reinforce the fusion site until the bone has grown strong enough to support the weight of the infant's head. Cervical immobilization is achieved through control of the head in relation to the thorax. For infants, there are many approaches that can be employed to stabilize the head including halo immobilization and noninvasive immobilization.

infant with halo immobilization

Halo Immobilization

In older children and adults, a halo ring and vest offer the most stability in protecting the cervical spine; however, there is an increased incidence of several complications in the infant population with this method.3,10 The skull's thickness is one consideration when attempting halo application on an infant. Since the skull is very thin, recommendations are to use eight to 12 pins at a reduced torque setting, ranging from "finger tight" only, up to two inches per pound for infants two years old and under.14 Re-torquing the pins 24 hours after application as performed in the adult population is not recommended for the infant patient for fear of skull penetration.11 As the child grows and becomes more mobile, the potential for falls increases, once again risking pin penetration, so parents should be advised to take extra precautions. While falling with a halo attached involves some risk, it is suggested by some that the risk of falling with an unbraced, unstable cervical spine is much more hazardous.12 Although using multiple pins reduces the risk of cranial bones shifting and distorting, practitioners should monitor the patient for this regularly due to immaturity of the sutures in the skull.14

Custom halo vests and rings may be necessary to accommodate the infant's physique. Angled blocks can be used to help accommodate the large head size in relation to the small body size as getting the rods through the vest and head block requires the rods to be angled out more severely than for adults whose head size is more proportional to their body.

Noninvasive Immobilization

There are several noninvasive, off-the-shelf (OTS) infant cervical immobilizers available that may be appropriate for infants who require stabilization. Depending on physician preference, cervical collars, cervical thoracic orthoses (CTOs), or cervical-thoraco-lumbo-sacral orthoses (CTLSOs) can be fit in a short time and be functionally adequate. However, OTS orthoses are generally made to fit infants of normal proportion. The difficulty with fitting infants with Larsen Syndrome and hyperkyphosis of the cervical spine is that due to the extreme nature of the kyphosis, the functional length of the neck can appear clinically short in stature while the head and torso are of more typical proportion. Such a short-statured neck has proven to make fitting OTS designs difficult although they are usually a good first option if customization is possible. If the halo and OTS options are not appropriate, custom orthoses can play an integral role. Casting, scanning, or using low-temperature plastics are all reasonable options to capture an impression of the infant's head, neck, shoulders, and torso for fabrication of a custom orthosis.

Image and Impression Capture

Obtaining a scanned image of an infant can be challenging because too much movement produces low-quality scans that are difficult to modify. Therefore, gravity-assisted positioning, along with a helpful parent or assistant to hold the infant still, should be used to obtain a high-quality scan. If scanning the head is necessary, the practitioner must avoid the infant's eyes with the laser scanner. If fabrication time has been allotted in the treatment plan, scanning the patient is a good option as it is the least invasive and causes the least amount of stress on the infant and his or her family.

Traditional fiberglass or plaster casting are viable options and can be used to get impressions of the infant's torso and/or head. Traditional casting is perhaps the most stressful option for the infant, so the practitioner must balance doing as little casting as necessary while still getting a thorough impression. When immobilization is needed on the same day of the evaluation, low-temperature plastics can play an integral role as they can be formed directly to the patient while the family waits. The challenge with low-temperature plastic is maintaining the infant in the desired position long enough for the plastic to cool and set.

Special Considerations

Special consideration should be taken for the frailty and sensitivity of infant skin as skin breakdown in areas of applied pressure is common.4 For newborn infants who are not yet able to roll over, fabricating a less traditional posterior shell positioning orthosis with added straps may be adequate to prevent cervical motion while also reducing skin contact to a minimum. This method relies primarily on gravity and secondarily on straps to hold the child in a safe and stable position. Care must be taken that the child's head is supported and held in a stable position if he or she should roll over. This approach should be abandoned once the child shows signs of being able to roll independently.

Conclusion

In orthopedic literature, all of these options are generally referred to as "custom orthoses" with little or no description of the actual orthosis. The responsibility lies with the practitioner to create a safe and effective orthosis through management of the patient evaluation, impression acquisition, fabrication, fitting, and follow-up. Overall, the patient must be closely monitored by the physician with radiographs to verify appropriate positioning within the chosen design. Growth should also be closely monitored if plans include extended orthosis wear. With proper management, good outcomes are probable.6

Kara Davis, CPO, LPO, MS, completed her undergraduate degree at the University of Michigan, Ann Arbor, and her O&P education at Eastern Michigan University, Ypsilanti. She is a practitioner at Texas Scottish Rite Hospital for Children, Dallas, and is the treasurer of the American Academy of Orthotists and Prosthetists (the Academy) Spinal Orthotics Society.

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References

  1. Herring, J.A., ed. 2008. "Larsen's Syndrome," in Tachdjian's Pediatric Orthopaedics (4th ed.), vol. 2, 1819-32. Philadelphia, PA: Saunders.
  2. Banks, J. T., J. C. Wellons 3rd, R. S. Tubbs, J. P. Blount, W. J. Oakes, and P. A. Grabb. 2003. Cervical spine involvement in Larsen's syndrome: A case illustration. Pediatrics 111 (1):199-201.
  3. Cooper, P. R., K. R. Maravilla, F. H. Sklar, S. F. Moody, and W. K. Clark. 1979. Halo immobilization of cervical spine fractures. Indications and results. Journal of Neurosurgery 50 (5):603-10.
  4. Gaufin, L. M., and S. J. Goodman. 1975. Cervical spine injuries in infants. Problems in management. Journal of Neurosurgery 42 (2): 179-84.
  5. Goldberg, M. J. 1987. The Dysmorphic Child: An Orthopedic Perspective. New York: Raven Press.
  6. Johnston, C. E., 2nd, J. G. Birch, and J. L. Daniels. 1996. Cervical kyphosis in patients who have Larsen syndrome. Journal of Bone & Joint Surgery, American Volume 78 (4):538-45.
  7. Larsen, L. J., E. R. Schottstaedt, and F. C. Bost. 1950. Multiple congenital dislocations associated with characteristic facial abnormality. Journal of Pediatrics 37 (4): 574-81.
  8. Latta, R. J., C. B. Graham, J. Aase, S. M. Scham, and D. W. Smith. 1971. Larsen's syndrome: A skeletal dysplasia with multiple joint dislocations and unusual facies. Journal of Pediatrics 78 (2):291-8.
  9. Laville, J. M., P. Lakermance, and F. Limouzy. 1994. Larsen's syndrome: Review of the literature and analysis of thirty-eight cases. Journal of Pediatric Orthopaedics 14 (1):63-73.
  10. Letts, M., D. Kaylor, and G. Gouw. 1988. A biomechanical analysis of halo fixation in children. Journal of Bone & Joint Surgery, British Volume 70 (2):277-9.
  11. Loder, R. T. 1996. Skull thickness and halo-pin placement in children: The effects of race, gender, and laterality. Journal of Pediatric Orthopaedics 16 (3):340-3.
  12. Madera, M., A. Crawford, and F. T. Mangano. 2008. Management of severe cervical kyphosis in a patient with Larsen syndrome. Case report. Journal of Neurosurgery: Pediatrics 1 (4):320-4.
  13. Micheli, L. J., J. E. Hall, and H. G. Watts. 1976. Spinal instability in Larsen's syndrome: Report of three cases. Journal of Bone & Joint Surgery, American Volume 58 (4):562-5.
  14. Mubarak, S. J., J. F. Camp, W. Vuletich, D. R. Wenger, and S. R. Garfin. 1989. Halo application in the infant. Journal of Pediatric Orthopaedics 9 (5):612-4.