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The following case study was written for Medtronic with consultation from: Michael-Gerard Moncman,
D.O., M.Sc., FACOS Clinical History and Presentation This 40-year-old male came to our attention in 1989. His left knee and low back were injured in 1975 in an automobile accident. He underwent a lumbar spinal fusion, but had continuing excruciating pain of the lower back and frontal midsection radiating bilaterally to his feet. He described this pain as burning and throbbing pain, with diffuse numbness from the knee downward. In 1986, the patient was assaulted, sustaining significant left facial injuries that resulted in chronic maxillary sinusitis. He underwent multiple surgeries to address this problem: debridement of the sinus, treatment of facial cellulitis, sinus and jaw reconstruction, and microvascular decompression of the trigeminal nerve. The pain in the lower left quadrant of his face was not improved by the surgeries. He was unable to chew or brush his teeth because of the pain. He was unable to sleep. If he ground his teeth during sleep he would awake with excruciating pain. He described the facial pain in the second and third trigeminal nerve distribution areas as a chronic ache with lancination. Since the onset of his pain in 1975, the patient had been treated with a wide variety of treatments and therapies, none of which had brought relief. In addition to the surgeries, he had undergone multiple rounds of physical therapy, biofeedback therapy, TENS, aqua therapy, oral narcotics, intramuscular injections of narcotics, cutaneous narcotic patches, and intravenous morphine. At the time of the patient's first visit with Dr. Khalouf, he was taking oral narcotics costing $600 per month and visiting the emergency department twice monthly for intramuscular injections of morphine. The patient's diagnoses were chronic mechanical and radicular pain secondary to failed back syndrome and chronic unremitting post-traumatic facial pain. His complex mixed pain problems involved both neuropathic and mechanical pain. He described both areas of pain as equally debilitating. A solution that would address both areas and types of pain was required. [Top]Intrathecal Morphine Infusion Therapy: Evaluation and Results Neurostimulation might have been helpful in addressing this patient's back and leg pain. However, a second system would have been required to stimulate the trigeminal nerve for the facial pain. Implanting two systems was not an attractive option. It was felt that intrathecal morphine therapy would be a more direct, less involved way of controlling the pain in both areas.Following appropriate evaluation, the patient underwent a two-day trial with morphine delivered epidurally by catheter. He responded within the first few hours of the screening test and was pleased to be able to brush his teeth for the first time since his facial injury in 1986. For some patients whose pain complaint is less well documented, placebo is alternated with the epidural morphine to determine that the response to the morphine is "real." Using a placebo was deemed unnecessary for this patient. Having demonstrated that the patient responded to the epidural morphine test dose, the challenge of the epidural trial was to find the morphine dosage that would effectively control the patient's pain. The patient was subsequently implanted with a SynchroMed® drug infusion system. The catheter was implanted in the lumbar spine at L3/L4 and directed cranially. The standard abdominal placement was chosen for pump implant. The patient was discharged from the hospital the day following the procedure. [Top]Post-Implant Patient Follow-up The patient's initial dose was set at 1/10th the epidural dose that had proven effective during the trial. The patient responded extremely well and was able to engage in many activities that had not been possible for him in many years—including chewing food, brushing his teeth, and sleeping. He was also able to resume his hobby of restoring vintage automobiles. The improvement in his quality of life was dramatic.Within the first six months of the patient's therapy, however, he experienced drug tolerance, marked by a rapid escalation of drug requirement and breakthrough pain. The patient was gradually withdrawn from the intrathecal morphine and a four-week therapeutic interruption (sometimes referred to as a "drug holiday") was instituted during which the patient's pain was managed with oral agents. The intrathecal drug delivery was then resumed. The patient at this time was able to achieve pain relief with a somewhat lower dose. Peaks in dosage that followed the therapeutic interruption were associated with a hospitalization for edema of the legs and sinus infections. The patient's dose requirements have actually decreased over time and have remained stable for the past seven months. The patient's pain is currently being managed on 1 mg of morphine per hour. He is pain-free in his face, back, and legs, and he is taking no other pain medications. He is now employed transporting cars to auctions throughout Pennsylvania. [Top]Discussion Drug addiction and drug tolerance are frequently expressed concerns with regard to intrathecal drug delivery for nonmalignant pain patients. Addiction is highly unlikely with this patient population and this delivery method, and tolerance is an issue that can be managed. Perhaps it is helpful to define three terms: tolerance, physical dependence, and addiction. Drug toleranceis the need for higher opioid doses to maintain the same analgesic effects. Tolerance to some opioid effects, such as respiratory depression, occurs routinely during chronic administration, permitting escalation of doses over time to achieve effective analgesia. Tolerance to analgesic effects is less common and can be managed with an occasional "drug holiday." Physical dependenceis a pharmacological property of opioids characterized by an abstinence syndrome following abrupt dose reduction or administration of an opioid antagonist. In contrast to the phenomena of physical dependence and tolerance, addiction is not a pharmacological property of opioid compounds. Addiction is a psychological and behavioral syndrome characterized by psychological dependence on a drug and aberrant drug-taking behaviors (Portenoy, RK. Cancer pain management. Seminars in Oncology. 1993:20(2, Suppl 1):19-35).The small dose of morphine that these patients receive delivered directly to the spinal receptors does not cause a euphoria or high, and does not cloud patients' sensorium. Rather, it relieves their pain. There is no opportunity for the psychological dependence and aberrant drug-taking behaviors characteristic of addiction to develop. Other than presenting themselves for refill on a scheduled basis, patients are not involved in the procurement or self-administration of the drug, and there is no ritual associated with the drug taking. So, while physical dependence is present, there is no psychological dependence or addiction. Drug tolerance may occur, as it did early in this patient's treatment experience. This can be addressed by withdrawing the intrathecal morphine therapy and substituting oral drugs until the spinal receptors have been desensitized. The intrathecal morphine can then be reintroduced, generally at a lower level than was needed prior to the therapeutic interruption. Colleagues often express qualms regarding "high" morphine dose levels. If the dose is escalating rapidly, then it is appropriate to determine whether it is due to a progression of the disease process, a problem with the drug infusion system (such as a leak in the catheter), or drug tolerance. If the dose increase is gradual, however, and is allowing the patient to function well with less pain and without side effects, then the dose is correct for that patient - regardless of the level. It seems inappropriate to implant a device and then to withhold the medication the device was intended to deliver because of our own preconceived notions of what "ought to be enough" morphine. The cost of the system is of concern to payors. The initial capital outlay for the SynchroMed drug infusion system, including the cost of the device, the procedure, and the hospital stay, is estimated at $20,000. While this is not an inconsequential cost, the system can be quite cost-effective. For example, in the year prior to this patient's pump implant, his chart documents healthcare utilization in excess of $36,000. This included 50 days of inpatient care (during four hospital stays), a visit to the emergency department, numerous consultations with various specialists, numerous diagnostic tests, antibiotic therapy, and a veritable market basket of prescription drugs. In his first year post-implant the patient was hospitalized for four days to treat edema in both legs. Including that hospitalization, the cost for the intrathecal morphine, and the refill charges, his healthcare utilization that year was estimated at approximately $10,900. For this patient, the pump "paid for itself" within the first year. As the patient has become more medically stable over time, his cost of care associated with pain relief has decreased. His current annual cost for his intrathecal morphine and refill is approximately $4,400. He is receiving no other pain medications. Obviously this represents a tremendous savings over his pre-implant care. Not only are there direct medical cost savings, but without intrathecal drug delivery with the SynchroMed system this patient would still be unable to brush his teeth, eat regular food, sleep or work-and he would be supported by the Workers' Compensation system. Today he is gainfully employed, living a normal life, and requires no additional pain medication. Not all patients will experience the same degree of success with intrathecal morphine therapy as did this patient. For a generalized comparison of intrathecal drug delivery with the SynchroMed system against alternative pain therapies, a probabilistic model or a randomized clinical study that captures the cost effects of various treatment outcomes (including possible complications) for both pump therapy and alternative pain treatments is required. Some would-be implanters are dissuaded from using this therapy by the required ongoing commitment to patient follow-up. The team approach to the therapy has worked well for us. We each have an independent practice, but when a patient requires an implantable therapy for pain, we collaborate. Dr. Khalouf takes responsibility for the initial patient evaluation and screening including the epidural morphine trial, and he also does the ongoing patient management. Dr. Moncman implants the drug infusion system and manages any wound or mechanical problems. Each member of the team draws on his strengths and interests to provide optimal therapy for the patient. 
This patient's rapid dose escalation early in his therapy was attributed to drug tolerance. A four-week theraputic interruption allowed therapy to be resumed at a somewhat lower dose level. Peaks in dosage following this theraputic interruption corresponded with a hospitalization for edema in the patient's legs and to sinus infections. Note that the dose required for pain control has declined over time and has remained stable at 1 mg per hour for the past 20 weeks. Pain Therapy Cost Summary for the Subject Patient*
* This
Cost Summary was based on extensive patient chart review. Costs related
to inpatient utilization were computed based on National Hospital Discharge
Survey data. Drug costs for pain related medications are based on the
Average Wholesale Price for drugs plus 30 percent. Individual results may vary. Not every individual will experience the same benefits. See Important Safety Information and Risks for information about the risks associated with intrathecal drug delivery. [Top]To see Patient Selection for Intrathecal Drug Delivery. . . To see Patient Selection for Neurostimulation . . . [Top]  IntroductionAbdominal
PainArachnoiditis
and Fibrosis PainBack
and Bilateral Leg PainCancer
PainChronic
Back and Leg PainComplex
Regional Pain Syndrome (CRPS) Dual-Site
Mixed PainIntractable
Thoracic Pain Post-Laminectomy
Syndrome |
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