A New Cervical-Thoracic Orthosis: Clinical Report of Seven Cases

Robert M. Catipovic, BS, CPO
Lillian A. Tittle, BS
Joseph C. Mollendorf, PhD

ABSTRACT

A new cervical-thoracic orthosis is described which provides cervical-thoracic stabilization, and is possibly less intrusive, less conspicuous, and more comfortable than other orthoses currently available. It rests and pivots on the wearer's shoulder, thereby transferring the weight of the head, via the shoulder pivot, to the wearer's shoulder and midsection. Our admittedly limited results show that the orthosis is relatively cool and comfortable, easy to clean, and aesthetically pleasing as it can be worn under clothing and concealed from general view. The orthosis is formed from one continuous piece of a suitably rigid material and generally conforms to the contours of the wearer's body. One size fits most users; however, it can be customized to conform to the contours of the wearer, even while the wearer is positioned in a corrective posture. The orthosis can also be used to incrementally adjust the position of the wearer's head or the curvature of the wearer's spine. A preliminary process for mass producing the orthosis has been demonstrated with a view toward a more sophisticated method of manufacture. Physicians have prescribed the orthosis for seven patients, and the initial qualitative results presented here are quite encouraging.

Introduction

A previous qualitative review of the structural properties and clinical application for six commonly prescribed cervical orthoses in terms of structure, ease of donning and adjusting, comfort, and their general clinical application suggests that, "Generally, as the orthosis becomes more restrictive, it also becomes more cumbersome and more difficult to don. Ease of adjustment and comfort are compromised (1)."

Another previous study of the relationship between dysfunction, causes of pain, and appropriate types of orthoses suggests that "simple cervical collars do not significantly reduce vertebral motion, so that more complex orthoses are required for cervical instability (2)."

A later review of the history of cervical orthoses and a study of the effectiveness of four cervical orthoses demonstrated that ". . . effectiveness . . . may have to be sacrificed for comfort (3)."

A more recent investigation reports measurements of the range of motion in flexion, extension, axial rotation, and lateral bending both actively and passively using a computerized motion analyzer for four orthoses: soft collar, Philadelphia collar, Philadelphia collar with thoracic extension, and a SOMI (4). It was found that the SOMI was most restrictive, but the differences in restriction for the collars tested were not usually large and the collars were less restrictive than previously reported. A conclusion was that the orthoses ". . . do not provide a high level of mechanical restriction of motion," and that, "The differences between the collars tested may not be enough to justify one of the more expensive or less comfortable collars."

Consequently, cervical orthoses that are currently available have inherent disadvantages to the wearer. They generally have a large surface area in contact with the skin, resulting in the undesirable trapping of perspiration and retention of body heat which can cause discomfort to the wearer. Such orthoses also are often bulky and cannot be worn under clothing. In addition, some of these orthoses are typically constructed of semi-rigid materials that are not resilient enough to retain their shape for more than several days of continuous use and are not stiff enough to provide full support during the course of required use.

Stabilizers are designed to transfer the entire weight of the head directly from the mandible to the chest. As a result, they are awkward and uncomfortable because they rest directly on the wearer's chest. In addition, stabilizers may not fit properly or may not stabilize patients with certain physical characteristics, such as kyphosis.

Furthermore, orthoses that are currently available are effectively only as barriers to further cervical flexion and extension. Consequently, they do not provide adequate positioning of the head for wearers whose problems result from improper positioning of the thoracic spine. For example, they are not effective in providing proper positioning for a wheelchair-bound patient who tends to slump forward. These orthoses are also unable to compensate for other abnormal forward curvature of the superior spine, in particular kyphosis.

The orthosis described here mainly controls capital flexion by supporting the head without requiring the use of the chest as a load-bearing surface. This feature improves wearer comfort by minimizing contact between the orthosis and the skin. There is minimal control of lateral flexion and rotation whereas capital extension can be controlled with an occipital strap. The orthosis may be worn beneath clothing with minimal anomalous cosmetic effects to the wearer, and, at the same time, can minimize the creation of uncomfortable load-bearing pressure points. Another important feature is it can be used to control the position of the head while repositioning the forward curvature of the thoracic spine. These features are incorporated into a simple design wherein one size fits most wearers.

The Orthosis

The orthosis described here distributes the force from the mass of the head to the shoulders and the inferior anterior torso through lever action pivoted at the shoulder (Figure 1 ). The orthosis is constructed of a moldable material and formed as a single piece with a mandible support and a pair of rigid arms that extend posterior along the wearer's inferior jaw and neck to the shoulders. These transverse arms join vertical arms at the shoulder and extend for a predetermined distance inferior along the posterior. At the inferior ends of the vertical arms, a belt fastens around the wearer's torso. In this manner, the downward force from the weight of the head on the mandible support is pivoted about the shoulders, and ultimately borne both by the shoulders (directly) and the inferior anterior torso (indirectly) by the inward pull of the belt. The simplicity of the one-piece design is evident. Note the built-in stiffening ridge along the outside surface in the vicinity of the shoulder.

The preproduction prototype orthoses were made of cast acrylic with thicknesses ranging from about 3/16 inch to about 3/8 inch in the fiberglass-reinforced region around the clavicle. The belt is made of 11/2 inch wide Dacron tape which is padded with 1/8 inch thick plastozote. The belt is riveted to the orthosis and is secured around the wearer with velcro. The entire orthosis is lined with 1/8 inch thick plastozote. Finally, the orthosis is made of nonferrous materials which obviates the need to replace titanium skull pins with low electron density materials to make the orthosis CT compatible (5).

A head strap may be added to the orthosis to limit capital extension. The potential effectiveness of a head strap is suggested by the results of a study (6) where it was found that a Minerva cervicothoracic orthosis with an occipital flare and forehead strap improved control of rotation and flexion/extension of the upper cervical spine below C1.

The orthosis may also be custom fit. With customized heat molding, the orthosis can be used to minimize kyphosis by repositioning the thoracic spine, causing the wearer to conform to a desired posture. It should be noted that the orthosis can also be fit to conform to such curvature, while at the same time maintaining its effectiveness in supporting the head. Finally, the orthosis is wearer-friendly as it is easy to don and doff.

Figure 2 depicts the orthosis worn on the outside of the clothing to better illustrate its function. Although the preferred color of the orthosis is a flesh tone, a dark-colored orthosis is modeled here for better visibility near the mandible and neck. It should be noted that the orthosis in these photographs was off-the-shelf, from a limited prototype production run, without any custom-fitting. Nevertheless, the fit is reasonable to demonstrate functionality and suggests that one size fits most.

Figure 3 depicts the orthosis as it is usually worn, under clothing, with only the mandible support visible. This presents a less conspicuous view than other currently available orthoses that are typically worn on the outside of the clothing. It can be seen that the orthosis is largely hidden from view and is nearly undetectable when viewed from the rear. It is expected that the orthosis can be comfortably worn on top of undergarments and beneath loose-fitting clothing with open collars.

Results

The qualitative results for the initial seven patients are shown in Table A .

The two patients who had poor compliance are residents at a developmental center. The staff is transient, which does not provide an ideal setting for patient compliance.

A common diagnosis for all seven patients was kyphosis, a difficult etiology to manage orthotically. The success of the orthosis in this regard suggests its ability to effectively control and correct a kyphotic spine; however, a quantitative investigation of this is beyond the scope of the present report.

Conclusions

It should be emphasized that neither a quantitative comparative study nor a quantitative evaluation of comfort and effectiveness in stabilizing the head was done here. Such quantitatiive investigations hopefully await future efforts. However, the qualitative results obtained from the seven patients discussed suggest that the orthosis may be effective in controlling a kyphotic spine. Cervical stabilization may also be achieved for a variety of different diagnoses. The orthosis may surpass the effectiveness, aesthetics, and comfort of other cervical-thoracic orthoses currently available for controlling a kyphotic spine. The simple design and an efficient manufacturing process yields a very lightweight, inexpensive, and effective orthosis. Two United States patents have been issued and foreign patent applications are pending.

Acknowledgements

The authors acknowledge James A. Ulrich for the photography and greatfully thank the National Science Foundation (award BES 9409900) and the Research Foundation of the State University of New York for support of this work.

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