Anatomically Correct Permanent Pacemaker Casing

Sergio Sanchez-Zambrano, MD Cleburne, Texas

Sergio Sanchez-Zambrano, MD Cleburne, Texas

The electronics of current implantable devices are outstanding and truly life-saving devices. However, the problem of size and configuration of these implantable devices has only been partially addressed, specifically on the issue of size reduction. As a result, I have designed and patented an anatomically correct permanent pacemaker casing based on the measurements of the curvature of the rib cage using CAT scan films. This device reduces the stress on the patient’s skin, can be implanted on the right or left side of the patient’s chest, reduces stress on the pacemaker lead, and has an accessible anchoring point. Clearly, it is not necessary to change the complete tooling of the pacemaker companies, but it is necessary to request of them to produce what is a better alternative for some of the patients (i.e., women who have had the need for both a mastectomy and radiation therapy). Size. When I began implanting pacers in 1973, I was impressed by the efforts of the manufacturers to reduce the size of the units.We all remember the yo-yo size of the Cordis and Medtronic units, and while indeed it was difficult to implant the pacers, we were very impressed and happy to be able to provide the ever-so-badly needed service. Imagine a pacemaker to those patients who needed them! Implant, Anchoring and Location. As time passed, the size did become smaller they were designed to be implanted on the right side; however, we were told to implant them on the left side, because there was significant stress on the leads. At the time of the anchoring and because of the unit’s thickness, you had two choices: either you did not anchor the device or you had to take it out to be able to pass the anchoring stitch. There are many chest X-rays showing migration of pacemakers. The First Relocation. In this male patient, the thickness of the skin was less than 5 mm; his pacer, in his words, was about to come out; it was very often painful, even with the slightest friction; and upon examination, there was a purplish discoloration, quite suggestive of ischemia. He was not very excited when I told him that because of the thickness of the edge of his pacemaker, we needed to relocate it and that failure to do so could infect it. This would also require complete extraction as well as several weeks of antibiotics and then a new pacemaker. He mumbled a few obscenities, something to the effect of litigations, but he agreed to the procedure. The second case moved me much more so. The woman had had bilateral mastectomy followed by radiation therapy, so when I saw her for the first time, she was quite uncomfortable. Despite her stoicism, her skin was friable and tender, the thickness of the pacer could not have been supported by such skin. I consulted with a thoracic surgeon and together we relocated the unit behind the pectoralis muscle. The patient and her family were pleased with the results. As one can imagine, each patient’s commentaries have been varied, from threats of litigation to disappointments. Patients Change, Pacemaker Casings Do Not. That was the message. I follow-up with most of the patients in whom I have implanted a pacer, as well as other patients that have moved into this area. There have been many cases of weight loss, diabetics, smokers, peripheral vascular disease, radiation therapies and mastectomies. These are the changes that I have seen more frequently that result in the need for an anatomically correct pacer. Adaptability of the Doctors. The Sin Equa Non hallmark of doctors is the resilient ability to adapt and continue to function despite all odds. In this case, to implant the pacer that we have available, we have been not only satisfied but impressed with the electronics of current devices and the physiologic assistance to the patients. However, the pacemaker casings continued to be thick on the edges, flat, and designed for the right side. At the time of the implant, you grin and bear it. We implant them, and the pacemaker representatives cannot offer another alternative, because there is none available. Eventually, I began to take pictures of each patient; the collection rapidly grew, along with my frustration at the time of each implant. CAT Scans and the Curves. I began to look at many CAT scans of the chest and measure the curvature at the level of most implants. When you overlap a pacer unit over the rib wall, the flat surface of the unit covers only one-third of the contact surface. The design demanded a natural curvature, thin edges, a reachable anchoring area and the ability to be implanted on either the right or left chestwall. Those basic principles are required for ALL implantable devices. Once I was satisfied with the results, the design was submitted to the U.S. Patent office and the patent was granted. There Shall Be More Implantable Devices. This sounds similar to the 11th Commandment, however, it is a fact. Recently, the FDA has granted approval to the largest corporation that produces pacemaker production for the atrial fibrillation units. This is only the beginning. Those wonderful electronic units have saved millions of lives all over the world. I have nothing but admiration for their accomplishments, but we must ask the manufacturers to produce anatomically correct casings. Benefits. There are many benefits to having an anatomically correct permanent pacemaker casing. The patient and their ever-changing body configuration would have available units that would follow the natural contour of his/her body, thereby reducing skin stress with potentially costly infections. The doctor would have the alternative to offer what would be the best choice for the patient. The manufacturer would have prevented potential litigation as well by simply anticipating problems and providing a solution. Conclusion. It is necessary to prevent the protrusion of implantable devices on the patients to prevent infections and potential medico-legal problems. There are three relevant factors to keep in mind: 1) Anatomically-designed casings are needed for ALL implantable devices, 2) Surgical skills of the implanting physician must be excellent, and 3) Habitus of the patients must be considered. The first two are correctable, the third one should not be ignored. The need for implantable devices continues to increase, therefore, the need to make them anatomically correct will also become more important. I have never expected that the manufacturers should change all their tooling, it would be dreadfully expensive. No, all that should occur is that the companies make some of the casings anatomically correct and have them available as an alternative for the patients that need them.