Medical Design Technology - January/February 2017

the same day. Inflatable bone tamp (IBT) technology comprises forming a balloon from extruded plastic tubing and mounting this onto the end of a stiffer plastic shaft.

A Y-adapter on the proximal end allows a removable stylet for column strength and a port for connecting an inflation syringe.

The peanut-shaped balloon is inflated into a sausage shape, providing a flattened surface for maximizing surface area to lift endplates.

The balloon represents an elegant solution because it is able to be inserted through a narrow diameter cannula and then inflated to a larger diameter to open up space around it. Inflatable balloon catheters are used in other anatomical locations, such as to open up blocked arteries, but bone represents a particularly challenging environment. The ability to engineer a balloon capable of being inflated within bone is a unique mechanical engineering challenge.

Such challenges include the trabecular bone within a vertebra being of heterogeneous density, resulting in pockets of harder bone adjacent to sections of softer bone.

This may be due to uneven fracture healing during the time before the patient undergoes BKP. Harder pockets are more difficult to reduce than softer bone, and can present sharp points that induce stress points in a flexible material. However, a flexible material has the advantage of distributing stress more evenly along the vertebral endplate, thereby reducing the chance for violating the endplate as compared to a rigid material that may have a high stress concentration.

Inflatable bone tamps (IBTs) are placed through the cannulas and inflated to reduce the fracture. Once the desired reduction is achieved, the IBTs are deflated and removed, leaving behind a void.

The resulting void is filled with bone cement, which acts as an internal cast to stabilize
the fracture.

BKP is a minimally invasive procedure for the treatment of pathological fractures of the vertebral body due to osteoporosis, cancer, or benign lesion. Keep in mind that results of this procedure may vary, and all treatment and outcome results are specific to the individual patient. Results may vary. A prescription is required. The complication rate for balloon kyphoplasty has been demonstrated to be low. There are risks associated with the procedure, including serious complications, and though rare, some of which may be fatal. These include, but are not limited to heart attack, cardiac arrest (heart stops beating), stroke, and embolism (blood, fat or cement that migrates to the lungs, heart, or brain).

Other complications include infection and leakage of bone cement into the muscle and tissue. Cement leakage into the blood vessels may result in damage to the blood vessels, lungs, heart, and/ or brain. Cement leakage into the area surrounding the spinal cord may result in nerve injury that can, in rare instances, cause paralysis. Please consult your physician for a complete list of indications, contraindications, benefits, and risks. Only you and your physician can determine whether this procedure is right for you. For more information, visit www.spine-facts.com.

Reduce and fix the fracture

Since balloons tend to inflate into the path of least resistance, they thus may form “balloon animals” inside a fractured vertebra, assuming an irregular shape rather than the desired inflation pattern. Careful material selection and processing helps to produce less compliant balloons with greater control, or a tendency to inflate to a pre-determined shape, similar to how mylar balloons inflate into shapes like stars or hearts. Detailed engineering allows the IBT to be rated to a maximum inflation pressure as high as 700 psi without rupturing, providing high power in generating a large force potential for lifting the vertebral endplates and reducing the fracture. Achieving this balloon shape and pressure during inflation helps to maintain the fracture reduction during introduction of polymethylmethacrylate (PMMA) bone cement into the newly-formed cavity.

Our balloon material is known to rupture when in contact with PMMA. Thus, a cement resistance technique has been developed to increase the amount of possible contact time and thus prolong the fracture reduction. By offering physicians access to the latest balloon technology, we are now able to offer the ability to control inflation pattern and the power to lift vertebral endplates, along with the ability to deliver bone cement while maintaining reduction.

Based on the largest clinical study comparing BKP and non- surgical management (Boonen et al., JBMR 2011), patients experienced reduced pain, improved function, deformity correction, and most importantly, improved quality of life. 3 MDT

1. National Osteoporosis Foundation Website.

www.nof.org

2. Brunton S, Carmichael B, Gold D et al. Vertebral compression fractures in primary care: recommendations from a consensus panel. J Fam Pract. 2005 Sep;54( 9):781-8.

3. Boonen S, Van Meirhaeghe J, Bastian L, et al. Balloon kyphoplasty for the treatment of acute vertebral compression fractures: 2-year results from a randomized trial. J Bone Miner Res. 2011; 26( 7):1627-1637.