The Kuehnegger Back Brace

Kuehnegger Back Brace

THE FIRST SCIENTIFICALLY BASED scoliosis brace was designed by W. Kuehnegger in the beginning of the seventies. It was based on a thorough evaluation of almost 100 earlier designs, most of which were totally useless. The outstanding exception was the Milwaukee brace which then had accumulated almost 30 years of experience. The purpose of the new design was to combine the advantages of the few good designs with collected ideas for improvement, which included improved cosmesis; one size for all patients, female and male; orthometric sizing without casting; improved fabrication and adjustability; avoid dental distortion; anterior opening; improved strength and durability with lower weight; improved hygienics.
The target of one size for all excluded infantile and juvenile patients. The new orthosis was designed for all adolescent scoliosis patients from nine to 15 years of age and over. Anthropometric data for this age group was converted to the orthometric dimensional data needed for the design. It was found that a single design could be used for 81 percent of the established patient range. A biomechanical analysis that considered both scoliosis and kypho-lordosis was performed using biokinetic data from earlier studies on orthoses.

Six prototypes were constructed and fitted to one test subject exhibiting a high kyphotic deformity. Of these, prototypes one, three, four, and five are shown above. Notice the use of flexible rubber tubing for the iliac crest ring and the provision for anterior closure. In the second prototype the mandibular support was changed to a round bar, while in prototype three this was made removable. The third model also introduced new plastic draw latches as closure mechanism. In the later prototypes the emphasis shifted to cosmesis and simplification of the basic design.

The streamlined final prototype six clearly shows the plastic draw latches of the anterior closure mechanism, the detachable mandibular support, and the occipital support on a single bar. This design was tried on the market, gathering experience that permitted further simplifications.

The pelvic band was hinged in the back and the posterior uprights continued into the shoulder bands. The prefinished components were cut to the required length and capped by vinyl tips. The basic design also provided for an axillary sling, a shoulder ring, an anterior shoulder pad, a sternal pad, a posterior kyphosis pad, or a neck ring sling, as needed. The designer summarized the features of this new and advanced brace as follows:

• Fabrication of the brace can proceed in any one of five directions;
• Fabrication is possible without casting, although this can be used as an alternative;
• The mandibular support can be removed for dressing, driving, eating and during donning and doffing;
• This is simplified by an anterior closure that retains a structural stability;
• The posterior hinge eliminates stresses and subsequent fractures in the pelvic section;
• The flexible rubber iliac crest segments constantly adjust to growth ;
• One size will fit most female and male patients of 9 to 18 years of age and over:
• Numerous adjustment features cover over 80 percent of the selected population;
• The open design eliminates perspiration and tissue problems, while other hygienic
• problems are reduced;
• The brace has an attractive cosmetic appearance in spite of the shoulder bars; The weight is reduced by 30 percent compared to other frequently used braces;

The orthometer was built on a vertical casting stand which held the patient with the required pelvic tilt and cervical traction, although this was eliminated later. The modular orthometer frame could be removed from the stand for further work. Its parts corresponded to the major structural components of the brace. The actual measurements were taken with pins graduated in millimeters which were deployed against the patient by finger rotation. The orthometer also provided a value for the superficial thoracic rotation that could be used to follow the progress of the treatment.

The orthosis was supplied as a kit containing all the components in electrostatically prefinished epoxy coated aluminum, as well as the required screws, rivets and plastic lining material. This was manufactured by Orthodyne, Inc. of Pleasant Lake, Michigan. Three major methods of fabrication were conceived. Preferably, the orthometer was used to measure the patient while the measurements were noted on data sheets and drawn on an orthogram. The brace was then assembled from the orthogram. A second method bypassed the orthogram, using the orthometer itself as a template. The third method enabled the orthotist to use his existing procedure of casting. These methods were expanded to five by including the possibility for central fabrication.

During the seventies the new brace was used by thousands of patients such as the girl in the images above. The average reduction of the scoliotic deformity was 11 degrees.

Further development, perhaps inspired by the new Boston brace, produced this short version of the CTLSO that was manufactured by Otto Bock.

Despite the impressive scientific foundation for the new CTLSO, it has left few traces in the scoliosis literature. Although thousands were made in the seventies, it soon disappeared without a trace. Perhaps it was too complicated and expensive in comparison with the simple and inconspicuous Boston brace that gained many followers in the late seventies. Any further information on the unique Kuehnegger orthosis that can reveal something of its fate is warmly welcome!