Academy Annual Meeting in New Orleans
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This year's Academy meeting was very well attended and included two full rooms of exhibitor displays and multiple concurrent educational sessions all day. It was physically impossible to attend all of the lectures, but many of those I did attend seemed to have better scientific content than in previous US P&O programs. The program was still dominated by the usual "what's hot and what's not" anecdotal clinical reports, but a growing percentage of speakers presented some objective data to support their primary contentions.
The first of the Thranhardt presentations was by Ing Marlo Ortiz who provided a fairly detailed overview of the transfemoral socket configuration he has been developing in his practice in Mexico over the past few years. Marlo has been gradually increasing his emphasis on medial and lateral weight bearing along the femur and ischiopubic ramus, while simultaneously lowering the anterior and posterior trimlines and de-emphasizing the role of the distal ischium.
This shift in focus is a logical extension beyond the current concepts of ischial containment alone, and the case results presented were quite impressive. Marlo was originally trying to improve the esthetic appearance of the socket to minimize gapping when the brim meets the pelvis, but soon recognized that there were other potential biomechanical advantages to this type of skeletal stabilization within the socket. Marlo is an experienced and well-respected clinician whom I've known for many years. I believe his ideas have significant merit and will gain wider acceptance over time.
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Marlo will be presenting a three-day hands-on workshop on his technique this Fall in cooperation with the Orthotic & Prosthetic Group of America. Details can be found at www.opga.com.
Jeffrey Nameth, CPO gave another well-documented presentation based on some of his original research into the effectiveness of cervical orthoses. The gist of his talk was that although one can draw general conclusions about classes of spinal orthoses, such as "CTOs generally provide more motion restraint than COs", it is difficult to predict differences between different CTOs. His studies demonstrated perceptible differences between the effectiveness of four post and alternative designs, and it was not always the orthosis with the most posts that provided the greatest immobilization.
Malcolm MacLachlan, PhD presented a very intriguing look at his work with phantom limb sensation and how it might be treated by virtual reality techniques. Dr. MacLachlan is a member of the Dublin Psychoprosthetics Group, a joint project between Trinity College Dublin and Dublin City University, composed of researchers and clinicians interested in applying aspects of psychology to the rehabilitation of people with amputations. The photo below is from their web site www.tcd.ie/Psychoprosthetics, and shows how a simple "mirror box" can be used to reflect the appearance of the left arm and hand so that the subject sees two intact limbs - one left and one right - even if the biological right arm has a transradial or lower amputation.
Keith Smith CO presented the final Thranhardt lecture, reporting on his case series of patients with significant coronal plane decompensations who were successfully treated with a custom TLSO with asymmetric contours. Keith's comments reflect a growing appreciation by the clinic team that centering the head over the sacrum may be a more important clinical consideration than achieving the lowest possible Cobb angle. In many ways, this talk was a reminder of the old saw to "always treat the individual and not the radiograph", and Keith made his arguments well.
Mechanical engineer Bill Contayannis gave a live videoconference from Melbourne, Australia on the dilemma of how to treat the patient whose body weight far exceeds the manufacturer's weight limit on the strongest commercially available components. He noted that, given the current epidemic of obesity in the US, this is an increasingly common challenge and one that is likely to continue to be a problem for the foreseeable future.
Much of the presentation focused on realistically identifying potential risks for product failures and then taking appropriate measures to reduce those risks. One of the interesting pieces of data Bill presented was that, at least in the Australian experience, those prosthetic patients who were unusually heavy did not experience a disproportionately large number of component failures. In fact, the distribution of known failures paralleled the approximate mass distribution of the general population, as shown in the slide below. So, it seems that although it is logical to be particularly concerned about durability when the patient is unusually heavy, one cannot assume that lighter individuals have a significantly lower risk of structural failures.
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Another major theme of Bill's lecture was that, contrary to popular opinion, collapse of a prosthesis or orthosis due to fracture of the components from a momentary overload is one of the less common failure modes. In the majority of cases Bill has studied, fatigue failure from repeated lower level loading over an extended period of time was involved. This has important clinical implications since there are a number of practical measures clinicians and technicians can take to increase the fatigue life of prostheses and orthoses, which he highlighted in detail.
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One of the important insights from Bill's research is that the patient's activity level is at least as important as body weight. In one experiment, researchers deliberately damaged prosthetic pylons and then applied loads at a frequency that simulated patients with varying body weight and activity levels. They also investigated the difference between 30 mm diameter and 34 mm diameter pylons of the same material. As the slide below indicates, the pylons that were 2mm larger proved to be far more resistant to failure, even if the individual was both heavy and active.
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The practical advice Bill offered was to set up an individualized inspection and replacement frequency for components when there are no commercially available options suitable for a specific patient's body weight or activity level. He discussed how to determine an appropriate initial inspection interval and then adjust the frequency based on the patient's clinical experience.
This session concluded with questions from the audience in New Orleans followed by Bill's real-time answers from Melbourne. Bill will be elaborating on these topics in much more detail, and covering a great deal of additional information on material science, at the Academy Advanced Training Series being held in Minnesota April 29-May 1. One of the highlights of this ATS is that attendees are invited to bring examples of prosthetic and orthotic items that have failed in their experience for analysis as part of the course. For additional information, go to www.oandp.org/education/seminars/advanced_training.
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There were a large number of interesting papers on upper limb prosthetic topics this year, including Bob Radocy's report on a nice alternative to the familiar ring harness that he calls the BAHA [Biomechanically Aligned Harness Anchor], which is an updated version of the dual ring harness described by Thomas L. Maples, CP in 1972. [Maples TL, A double-ring harness for the bilateral above-elbow amputee. ICIB 1972; 11(9): 1-3] Like all "cross back strap" variants, this geometry moves the control attachment strap and distal axilla loop more inferiorly, so that they cross the lower third of the scapuli. This increases both the biomechanical efficiency of the harness and reduces axilla pressure compared to the more familiar cross point that is sewn or formed from a ring. Visit www.oandp.com/products/trs/ for more details in this and other recent upper limb innovations.
Julie Shaperman, MSPH, OTR summarized a survey of 80 pediatric transradial deficiency fittings, noting both the similarities and differences in the protocols at differing clinics across the country. As the literature suggests, most children are initially fitted by 6 months of age, typically with a passive terminal device. When this prosthesis requires replacement, at about 18 months, most centers provide an active terminal device. About half the children received a myoelectric prosthesis as their first active prosthesis; the other half used either a voluntary opening or voluntary closing terminal device.
Robert Lipschutz, CP gave a nice succinct case review of his work with a gentleman who acquired two shoulder disarticulation amputations in an industrial accident. Todd Kuiken, MD and surgical colleagues at the Rehabilitation Institute of Chicago used nerve transfers to innervate various fibers of the pectoralis muscle on one side to provide multiple, independent myoelectric controls to operate a prosthesis. The Chicago Public Broadcasting System TV station recently featured this patient, and has posted streaming video and a written summary of this program at www.pbs.org/newshour/bb/science/july-dec03/roboticarms_11-18.html.
The Prosthetic Technology Forum on Microprocessor Knees was a good review of the basic principles and current consensus regarding this aspect of clinical practice. Joe Miller, CP gave a nice summary of the currently available microprocessor-controlled prosthetic knees, noting that more than 20,000 such prostheses have now been fitted successfully worldwide. I couldn't help but note how ironic it was that Anthem Blue Cross and Blue Shield insurance recently announced a national policy stating that such components are "considered not medically necessary in all cases" and therefore no longer provided for any of their beneficiaries. Anthem has also decreed that myoelectric prostheses are not medically necessary in all cases, so apparently their subscribers can only receive upper limb prostheses if the design was developed more than half a century ago. [This policy is online at www80.anthem.com/jsp/antiphona/bcbs/nav/ilink_pop_native.jsp?content_id=PW_040591.
There were many other good sessions that were concurrent with these lectures, so this summary is just a sampling of the information available at this Academy meeting.
Exhibit Hall:
Not only were there so many scientific sessions that it was impossible to attend them all, there were a record number of display tables filling two full rooms that made it a real challenge to see all the new items on display. Fortunately, the breaks and lunches were available in the exhibit area and this time was unopposed by scientific presentations. I made a concerted effort to get to each and every table, but I'm sure I still overlooked some things.
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There was no real "buzz" this year that everyone was talking about, but there were a fair number of nice incremental advances on display. One of the slickest new orthotic components I spotted was the Tamarack Clevisphere TM ankle joints. This is the latest brainchild from Marty Carlson, MSE, CPO, and like his other ankle joint concepts, it is elegantly simple and clinician friendly.
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Each Clevisphere TM is a metal ankle joint about the size of a Tamarack Flexure Joint that provides an infinitely adjustable stop in one direction. Because each joint also allows a 24 degree range of rotary motion, they are self-aligning when used in pairs, and therefore make it easy to maintain congruency with the bimalleolar axis. Each pair of joints includes the necessary plastic dummies for one-pull thermoforming of an AFO segment. These should make great plantarflexion stops, and are suitable as dorsi stops for smaller individuals such as children. For more information, go to the Tamarack web site at www.oandp.com/products/tamarack.
Becker was showing a very sleek new ratchet-locking knee joint that is available in peds and adult sizes, with aluminum, titanium, or steel side bars. Details are posted at www.beckerorthopedic.com/ratchet_lock/ratchet_lock.htm. You might also check out the Wilmer orthosis, which Becker now distributes, at www.beckerorthopedic.com/ratchet_lock/ratchet_lock.htm.
One upper limb orthosis caught my eye: the SADER series from Innovative Joint Technologies, designed by Ron Hopkins, CP. I've always favored using the simplest mechanical solution to a given problem, and the SADER orthoses are based on elastic shock cords that provide low level, long term stretch to work out contractures. Details are online at www.ijtonline.com.
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There were several incremental advances in prosthetic items too. OSSUR had a slew of new orthotic and prosthetic products, but one of the most intriguing was their new "Seal-In" liners. These are based on the same proven concept as Hypobaric limb socks: a vacuum seal in the distal third of the sleeve combined with an expulsion valve creates suspension without encumbering the next proximal joint with a knee sleeve or elastic suspension belt.
The patient model they had demonstrating the transtibial version suggested lightly lubricating the gasket prior to donning. Under body weight, the liner slid smoothly into the socket and the gasket compressed until it was flush with the outside of the liner once the socket was fully donned. Suspension was superb: every bit as secure as sleeve-valve suction, but without the restriction in knee motion. Touching the valve immediately released the suction and the socket came off easily.
The sealing gasket can be reflected distally so that a cut-off spacer socket can be applied to accommodate volume changes. When the gasket is rolled back into its normal position, the sock is anchored in place pretty well. This should accommodate at least moderate volume changes.
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For more information, go to www.ossur.com/template1.asp?pageid=1136. OSSUR also showed their microprocessor-controlled Rheo knee for the first time at the Academy meeting, but it is not yet commercially available.