Michael S. Turner

Mortality Associated with Implantation and Management of Intrathecal Opioid Drug Infusion Systems to Treat Noncancer Pain

Background:In 2006, the authors observed a cluster of three deaths, which circumstances suggested were opioid-related, within 1 day after placement of intrathecal opioid pumps for noncancer pain. Further investigation suggested that mortality among such patients was higher than previously appreciated. The authors performed investigations to quantify that mortality and compare the results to control populations, including spinal cord stimulation and low back surgery. Methods:After analyzing nine index cases–three sentinel cases and six identified by a prospective strategy–the authors used epidemiological methods to investigate whether mortality rates reflected patient- or therapy-related differences. Mortality rates after intrathecal opioid therapy and spinal cord stimulation were derived by correlating Medtronic device registration data with deidentified data from the Social Security Death Master File. Aggregate demographic and comorbidity data were obtained from Medicare and United Healthcare population databases to examine the influence of demographics and comorbidities on mortality. Results:Device registration and Social Security analyses revealed an intrathecal opioid therapy mortality rate of 0.088% at 3 days after implantation, 0.39% at 1 month, and 3.89% at 1 yr–a higher mortality than after spinal cord stimulation implants or after lumbar diskectomy in community hospitals. Demographic, illness profile, and mortality analyses of large databases suggest, despite limitations, that excess mortality was related to intrathecal opioid therapy, and could not be fully explained by other factors. These findings were consistent with the nine index cases that revealed that respiratory arrest caused or contributed to death in all patients. No device malfunctions associated with overinfusion were identified among cases where data were available. Conclusions:Patients with noncancer pain treated with intrathecal opioid therapy experience increased mortality compared to similar patients treated by using other therapies. Respiratory depression as a consequence of intrathecal drug overdosage or mixed intrathecal and systemic drug interactions is one plausible, but hypothetical mechanism. The exact causes for patient deaths and the proportion of those deaths attributable to intrathecal opioid therapy remain to be determined. These findings, although based on incomplete information, suggest that it may be possible to reduce mortality in noncancer intrathecal opioid therapy patients.

Prevention of Intrathecal Drug Delivery Catheter‐Related Complications

In an effort to improve the performance of implantable intrathecal drug delivery systems, a group of physicians experienced in the management of such devices reviewed surgical practices and principles that were associated with low catheter‐related complication rates. Clinical study and postmarket data identified physicians whose patients experienced a relatively low rate of catheter‐related complications. Six of those physicians (three anesthesiologists and three neurosurgeons) reviewed the number and types of intrathecal drug pumps and catheters they had implanted, with an emphasis on the specific details of successful catheter implantation techniques. The authors pooled their experiences to reach a consensus on implant techniques that are associated with a low rate of postoperative complications.

Medical Practice Perspective: Identification and Mitigation of Risk Factors for Mortality Associated with Intrathecal Opioids for Non-Cancer Pain

OBJECTIVE The authors recently determined that early and longer term mortality after initiation or reinitiation of intrathecal opioid therapy is higher than previously appreciated: 0.088% within 3 days, 0.39% at 1 month, and 3.89% at 1 year. These rates were 7.5 (confidence interval, 5.7-9.8), 3.4 (confidence interval, 2.9-3.8), and 2.7 (confidence interval, 2.6-2.8) times higher, respectively, at each interval than expected based on the age- and gender-matched general U.S. population. A substantial portion of this excess mortality is probably therapy related and cannot be entirely accounted for by underlying demographic or patient-related factors, or by device malfunctions. We also analyzed multiple complementary internal, governmental, and insurance databases to quantify mortality and to identify medical practice patterns that appear to be associated with patient mortality risks, and to suggest measures for physicians and health care facilities to consider in order to reduce those risks. Both of those objectives involve judgments, which may be controversial and are subject to practical limitations. RESULTS Multiple clinical and patient- or therapy-related factors appear to increase the risk for early post-implant mortality. Specific risk mitigation measures associated with each factor include: close attention to the starting intrathecal opioid dose (or restarting dose after therapy interruption); avoidance of outpatient implant or other device procedures that involve less than 24-hour monitoring for respiratory depression; supervision of concomitant opioid, respiratory depressant, or other central nervous system active drug intake early post-implant and chronically in the outpatient setting; and careful programming or dosage calculations and decisions in order to avoid the unintentional administration of high intrathecal opioid drug doses. CONCLUSIONS Mortality after initiation of or device interventions in intrathecal drug delivery patients appears to occur as a result of multiple factors that present possible mitigation opportunities for physicians and health care facilities.

Intrathecal Baclofen Therapy: An Update

Intrathecal administration of baclofen is a well‐established technique for modulating hypertonia secondary to upper motor neuron pathology. Despite the nearly 2 decades of widespread clinical use, this intervention presents many challenges to even experienced clinicians. The purpose of this clinical review is to describe some of the intricacies and subtleties of this treatment strategy. This narrative provides an overview of 3 topics: (1) an alternative methodology for intrathecal baclofen trials; (2) an algorithmic approach to troubleshooting intrathecal delivery systems; and (3) the utility of neurophysiologic assessments within various phases of intrathecal baclofen therapy.

Migration of a distal shunt catheter into the heart and pulmonary artery: report of a case and review of the literature

IntroductionA rare complication of ventriculoperitoneal shunt placement is the proximal migration of the distal catheter into the heart and pulmonary artery. There have been 12 reported cases regarding intracardiac migration. In five of the cases, the catheter traveled further into the pulmonary vasculature.Case reportThe authors report another case regarding the latter situation where the catheter tip localized in a right upper lobe pulmonary arterial branch. Removal of the catheter was complicated by redundancy of the catheter and a knot along the catheter. Nevertheless, extraction was successful via endovascular retrieval using interventional radiology and loop snares. Catheter migration likely began where the right internal jugular vein was penetrated during the initial shunt placement. Subsequent venous flow and negative intrathoracic pressure coordinated the proximal migration of the catheter. The authors provide a literature review to provide information regarding management of this rare complication.

Surgical Management of Spasticity in Persons with Cerebral Palsy

Cerebral palsy is a disorder that primarily affects the neurologic system but secondarily affects the musculoskeletal system through the effects of spasticity, dystonia, and other movement disorders. The treatment of cerebral palsy requires a multidisciplinary approach with treatment aimed at modulating the movement disorder through oral medication, injectable drugs (phenol, botulinum toxin), and physical and occupational therapy. Treatment of the neurologic effects of the central movement disorders include selective dorsal rhizotomy, intrathecal baclofen pump placement, and potentially deep brain stimulation. Although any effect on tone is temporary, orthopedic surgery has an important role in the treatment of the musculoskeletal deformities and contractures present in the child with cerebral palsy. Orthopedic surgery improves function by lengthening the musculotendinous structures, transferring tendons, performing osteotomies to reduce dislocated joints, and normalizing rotation and fusion of selected joints to improve stability. Neurosurgical techniques are not as widely used, but may reduce spasticity in select individuals. The combined approach of managing tone and normalizing the biomechanics of the spine and upper and lower extremities through orthopedic surgery and neurosurgery and subsequent rehabilitation is the cornerstone of treatment of the child and adult with cerebral palsy.

The treatment of hydrocephalus: a brief guide to shunt selection

The placement of a cerebrospinal fluid shunt system is a procedure that most neurosurgeons feel comfortable performing. The procedure is fraught with many pitfalls and the choices of equipment are staggering. We review the recent literature on shunt systems. We describe the newer shunt systems and procedures and identify possible roles for them in shunt procedures by the neurosurgeon in practice.

Assessing Syndromes of Catheter Malfunction With SynchroMed Infusion Systems: The Value of Spiral Computed Tomography With Contrast Injection

Medtronic SynchroMed pump systems have been implanted in more than 100,000 patients to infuse medication into cerebrospinal fluid. The primary medications delivered are baclofen and analgesics (eg, morphine, hydromorphone, bupivacaine, ziconotide). Patients receiving intrathecal medications are sensitive to changes in the infusion and may have a number of unique clinical presentations related to loss of drug delivery. Malfunctions of the infusion system are typically from catheter problems. The clinical presentations of 7 syndromes of catheter malfunction in patients receiving intrathecal medication will be described: microleak syndrome, delayed leak syndrome, catheter tip loculation, subdural catheter syndrome, catheter migration syndrome, ventriculoperitoneal shunt malfunction syndrome, and catheter tip inflammatory mass. The syndrome, diagnosis, and treatment strategies for each will be discussed. The use of spiral computed tomography after injection will be described.

Validity of Radionuclide Cerebral Angiography for Diagnosing Brain Death in Infants

Since 1969, we have been using intravenous (IV) radionuclide cerebral angiography (RCA) as a confirmatory test for brain death in both children and adults (Goodman and Heck, 1977; Goodman et al., 1969, 1985). However, a recent highly respected consensus report (Report of the Medical Consultants on the Diagnosis of Death, 1981) has advised caution in using adult-based criteria for determining brain death in children, implying that a young child with a severe neurological insult may have greater recovery potential than an adult in a similar situation. In order to respond to concerns raised about the validity of RCA in diagnosing brain death in very young patients, we have reviewed our recent results with this technique in infants under 2 years with suspected brain death.