Principles of Orthotic Management

Extrication Collars

Extrication collars are commonly placed on trauma victims at accident scenes by emergency medical personnel. The most common type is one with a rigid plastic front and back section that is primarily constructed to prevent further flexion or extension of the cervical spine during transport. These collars are not designed for long-term use, frequently do not have any soft padding material, and, in general, fit poorly. Consequently, these should be removed as soon as possible, and several investigations have shown that extrication collars lead to pressure ulcers, pain, and discomfort. Furthermore, biomechanical studies have shown that extrication collars do not offer adequate stability within the upper cervical spine and craniocervical junction. These factors make extrication collars a poor choice for long-term orthotic fixation. They should be limited to the field evaluation and emergency transportation. Once the patient is evaluated by the appropriate spine or trauma service, the extrication collar should be replaced by a more appropriate type of orthosis described in the following sections.

Cervical Traction and Halo Ring

Cervical traction is used to correct abnormalities in spinal alignment associated with traumatic or congenital etiologies. Cervical traction is accomplished with the application of skeletal tongs ( Fig. 37.1 ) that are secured to the skull by pins that penetrate the outer cortical table.

Multiple forms of tongs are available on the market. Gardner-Wells tongs (see Fig. 37.1 ) are the most widely accepted and used because they are easy to apply and durable. To apply Gardner-Wells tongs, the patient is placed in a supine position with the healthcare professional standing at the head of the bed. The standard pin sites are 1 cm posterior to the external auditory meatus and 1 cm superior to the pinna. This allows for good purchase in bone of the pins and avoids the superficial temporal artery or the bulk of the temporalis muscles. Slight anterior/posterior and/or asymmetric placement of the pins can be used to better facilitate the reduction of spinal deformities as needed. Pin sites should be cleaned and prepped in the standard sterile fashion, and usually local anesthetic is injected into the pin sites before the pin insertion. Gardner-Wells tongs have a spring-loaded pin on one side to assess tightness. As the pins are tightened a small rod extrudes from the pin body. Sufficient pin tightness is achieved when the load rod extrudes 1 mm from base of the pin. The pins should be tightened in an alternative fashion. Side nuts are tightened to prevent inadvertent tightening of the pins. After satisfactory tong placement, the pins are retightened in 1 day to avoid loosening of the pins. Finally, standard pin site care is applied by the nursing staff daily to avoid pin site infections. The amount of traction weight is dependent on a few factors, including surgeon preference and type of injury, but a general rule of thumb is to begin with 5 to 10 pounds per spinal level.

Unlike Gardner-Wells tongs, the halo ring is affixed onto the skull with four pins. This generates a stronger fixation and distributes the force more evenly. More important, the biggest advantage is the convenience of attachment to a halo vest ( Fig. 37.2A ) when the spinal deformity is reduced. Modern halo rings are made from titanium or carbon materials and therefore are all both computed tomography and magnetic resonance imaging compatible. There are a variety of halo ring sizes designed to fit all patients, including young children. The appropriate halo ring size can be selected by measuring of the head circumference and then referencing this measurement to the manufacturer's sizing chart. As with the tongs, halo rings are applied with the patient in the supine position. The ring is held in place with three temporary nonpenetrating pins ( Fig. 37.2B ). It is important that the ring is affixed just below the equator of the head (usually about 1 cm above the eyebrow and 1 cm above the pinna) so that it does not become loose over time superiorly. The four actual penetrating pin sites are then selected. The optimal sites for the two anterior pins are approximately 1 cm above the eyebrow and about two-thirds lateral from the midline to avoid both the supraoptic nerve and frontal sinus. The optimal posterior pin sites are approximately 180 degrees from the anterior pin and just slightly below the equator. Once the entry sites for the penetrating pins are chosen, the selected area is prepped with Betadine and then injected with local anesthetic. Shaving of the posterior pin sites is required so that hair does not wrap itself around the pins during insertion and to allow access for pin care later. The pins are then inserted perpendicularly and tightened diagonally with a torque screwdriver to 6 to 8 pounds. Locking nuts are then placed over the pins to secure them in place ( Fig. 37.2C ). Skin care for halo pin sites is similar to that for tongs. Once the halo ring is secured, a traction adaptor can be placed and then traction weight applied. The pins are retightened at 24 hours but no further after that. If pins loosen during treatment they should be replaced at another location.

Halo Vest

Modern halo vests are the most stable fixation for the occipito-cervical junction. This consists of the halo ring ( Fig. 37.2D ) that is attached to a halo vest by four rod posts. For the device to achieve maximal stability, it is important that the appropriate vest size is chosen and fitted. Unlike many of the orthoses that we will describe later, the halo vest is invasive. This leads to the unique potential complications associated with the halo, including pin site infection or skull penetration. Once fitted and attached to the halo ring, the halo vest fittings should be tightened with a torque wrench to 30 to 32 pounds. Just as with the halo ring, the halo vest should be retightened regularly to avoid loosening over time. Because the halo vest is bulky and the wearer loses the ability to flex/extend the neck, we recommend a short course of physical/occupational therapy so that the patient can adapt to the unwieldiness of the halo to avoid further falls or accidents. In older patients halo vests are associated with dysphagia, aspiration, and higher mortality risk and should be used with caution.

Soft Cervical Collar

Soft collars are cylindrical foam neck collars. They do not limit cervical motion, but rather serve as a cushion and a reminder to avoid any strenuous activity or motion. Soft collars are mainly used for soft tissue injury or comfort. Like all orthoses the soft collar must be of proper size, which includes both height and girth.

Hard Cervical Collar

Hard cervical collars ( Fig. 37.3 ) have rigid support for the occiput and mandible and extend down to the clavicle and shoulders (upper thoracic spine). There are a variety of commercially available hard cervical collars, including Philadelphia (Thorofare, NJ), Aspen (Irvine, CA), Miami J (Moorestown, NJ), PMT (Chanhassen, MN), Malibu (Jackson, MI), NecLock (Moorestown, NJ), and others. They differ primarily in material, rigidity, comfort, and style. There are a number of sizes and they are adjustable for proper fit. Most brands of collar offer an anterior opening for access to a potential tracheostomy. Biomechanical studies have demonstrated that hard cervical collars are effective in significantly reducing neck movement. Common indications for cervical collars include stable fractures that involve the occipital condyles, atlantoaxial complex, and subaxial spine. Sweating beneath hard collars can lead to skin maceration. Some designs use special fabrics that wick sweat away from the spine and can be washed to minimize skin irritation.