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Implantable Pain Therapies-What Training is Required?

Palmer, Pamela Pierce MD, PhD

doi: 10.1213/00000539-199906000-00003

Pain Management Center, Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California.

Accepted for publication February 23, 1999.

Address correspondence and reprint requests to Pamela P. Palmer, MD, PhD, Pain Management Center, Department of Anesthesia, University of California San Francisco, San Francisco, CA 94143-0648.

Implantable devices, such as intrathecal pumps and spinal cord stimulators, are an important part of the armarmentarium for many pain management physicians. Although most patients suffering from chronic pain can be treated effectively using noninvasive modalities, the availability of these implantable devices allows patients with otherwise refractory pain states to achieve some degree of relief. Intrathecal delivery permits the use of smaller doses of medications, such as opiates and/or baclofen, which can decrease side effects seen with systemically administered drugs. Furthermore, medications such as local anesthetics or clonidine, which cannot effectively be delivered systemically, can be delivered intrathecally. These medications alone, or in combination with an opioid, can benefit the patient suffering from neuropathic pain that has not responded well to oral neuropathic pain medications, such as tricyclic antidepressants or membrane-stabilizing drugs. Spinal cord stimulators (SCS) implanted for the treatment of pain can provide a drug-free method for locally targeting pain pathways by selective placement of the stimulator lead in the epidural space. These devices are potentially advantageous in the elderly, who often have more pronounced reactions to the side effects of systemic medications.

The increased potential for pain relief from implantable devices must be weighed against the potential problems (e.g., wound infections, meningitis, equipment failures, or programming errors). Factors that determine whether an implant will be successful include the etiology of the pain, the psychosocial background of the patient, and the pain physician's implant skills, drug selection, and/or device selection. Each of these three broad areas requires skillful analysis to determine the benefits/risks of implantable devices. The etiology of a complex pain problem is often difficult to determine. It is therefore important to perform therapeutic trials before permanent implantation to determine whether the proposed implantable device is indeed effective for the individual patient. Psychological background is extremely important and includes many variables, such as Axis I or II disorders or unrealistic expectations of the treatment, which can undermine any effort to achieve satisfactory pain relief with implantable devices. Therefore, a psychiatric evaluation of all implant candidates is warranted before implantation. The trial period is important not only to determine efficacy, but also to avoid unrealistic patient expectations. The third factor-skill and knowledge of the pain physician-is arguably the most important variable in determining the success or failure of implantable devices. It is within the context of all these factors that the survey by Fanciullo et al. [1] in this issue of Anesthesia & Analgesia should be considered.

Their survey provides important data regarding overall statistics of implantable devices in academic pain centers in this country, such as the average number of pain physicians using these various devices, duration of the trial periods, etc. However, the authors' main focus is the training of fellows in the use of implantable techniques. Specifically, the issue is raised as to whether a 3-day course in implantable techniques is adequate training for fellows whose experience has been in a nonimplanting pain management program. The authors also raise the question of whether industry should be involved in such a course by providing scholarships to fellows.

The emphasis placed on this training course, known as the Interventional Training Workshop (ITW), is surprising. As previously mentioned, placement and management of implantable devices for the treatment of intractable pain requires thoughtful selection of patients and a skilled, experienced implanter. Can a 3-day workshop provide anything other than a cursory introduction to devices and techniques? In fact, the ITW clearly states that the course in no way authorizes the participants to implant devices. For directors of nonimplanting programs to state that they consider this 3-day course adequate training for fellows to implant clearly shows that they lack experience in this field. Gone are the days when only morphine was used in neuraxial infusion pumps. The addition of a local anesthetic, clonidine, baclofen, and other drugs to the infusion solution has revolutionized the treatment of "opioid-resistant" pain. Not only is an intimate knowledge of these drugs and their side effects necessary, choosing the right pump is also vital. Currently, Medtronic (Minneapolis, MN) has an 18-mL programmable pump approved for the management of chronic pain. Arrow (Reading, PA) has non-programmable constant-rate pumps with reservoirs of varying sizes (up to 50 mL). For patients who require a local anesthetic in their pump solution, the advantages of a larger reservoir (i.e., greater time between refills) must be weighed against lack of programmability.

When considering SCS, it is critical to understand that these devices have become perhaps more complex than infusion pumps. Both Medtronic and Advanced Neuromodulation Systems (Allen, TX) have produced a complex array of different leads, receivers, and generators to meet the many pain conditions that can be effectively treated with SCS. The number, spacing, and size of the electrodes per lead and the number and position of leads can be chosen depending on the type and location of the pain being treated. A potentially successful SCS trial/implant can fail if improper leads or placement are chosen. Because of the complexity of implantable devices, perhaps an additional fellowship year devoted specifically to the science and art of implanting is necessary for physicians who plan to incorporate implantable devices into their pain practice. This might not be necessary for fellows who have had extensive implant training during their initial fellowship year.

There is no certification in implantable pain therapies, and there is no formal requirement as to the number of implants performed (success rate, etc.), other than the proctoring rules for individual hospitals and surgical centers. We must seriously consider instituting certification requirements for pain physicians who want to implant these devices. As anesthesiologists assuming the role of implant surgeons, we are under scrutiny by other surgeons, as well as managed care companies who would question our motives, our indications, and our outcomes. Our best defense is a satisfied postimplant patient who has benefited from our in-depth training in implantable pain therapies; in fact, it is our only defense. I agree with Fanciullo et al. [1] that neither the ITW, nor any other cadaver course, should be considered adequate training for implanting pain management devices. I believe, however, that our commitment to the proper training of pain management fellows in implantable devices goes well beyond overseeing the course content of the ITW. Hopefully the article by Fanciullo et al. [1] will serve as a stimulus for further discourse on how implant physicians should be trained and, possibly, certified.

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1. Fanciullo GJ, Rose RJ, Lunt PG, et al. The state of implantable pain therapies in the United States: a nationwide survey of academic teaching programs. Anesth Analg 1999;88:1311-6.
© 1999 International Anesthesia Research Society