Radioisotopic control for baclofen pump catheter failure

Unique form of catheter malconnection following intrathecal baclofen surgery for spinal cord injury: a case report

This case report concerns a patient suffering from traumatic spinal cord injury with severe spasticity treated with intrathecal baclofen therapy. After revision surgery for a confirmed catheter obstruction, progressive spasticity reappeared. Diagnostics demonstrated signs of catheter fracture or disconnection adjacent to the pump. During revision surgery, the silicone layer surrounding the sutureless pump connector was shown to be curled up, revealing the cause of dysfunction. As far as we know, this form of malconnection has not been reported before. Therefore, surgeons must be aware of this complication and additional inspection of the silicone connector prior to definite connection is advised.

Evaluation of usefulness of scintigraphic imaging in diagnosis of intrathecal drug delivery system malfunction - a preliminary report

BACKGROUND

Implantable intrathecal drug delivery systems (IDDS) are basic tool enabling chronic intrathecal pharmacotherapy. Lack of expected clinical results of IDDS therapy necessitates search for the cause with the help of diagnostic imaging methods among other things. Beside radiological techniques, it is also possible to visually assess IDDS systems by nuclear medicine methods. In this study we assess utility of radioisotopic methods in differential diagnosis of failure of therapy with IDDS systems.

MATERIAL/METHODS

Scintigraphic studies were performed in selected patients with neurological diseases associated with spasticity, who had IDDS system implanted and were unable to maintain satisfying clinical effect of inrathecally infused baclofen. After emptying the IDDS system of the drug, radiotracer (99mTc-DTPA) solution was injected into the pump reservoir. Subsequently, a series of scintigraphic images was registered, demonstrating passage and distribution of the infused radiotracer.

RESULTS

In all investigated cases, scintigraphic study resulted in acquiring relevant additional diagnostic information. Normal or disrupted distribution of radiotracer in spinal canal allowed for a diagnosis drug resistance or demonstrated presence of arachnoid adhesions respectively. Early appearance of radiotracer in blood was considered a proof of leak. Our examinations had decisive influence on further patient treatment, allowing for diagnosis of drug resistance in one patient or complication related to IDDS system in three other cases including breakage of a catheter, pump malfunction and arachnoid adhesions.

CONCLUSIONS

Scintigraphic methods carry significant amount of information facilitating final diagnosis of the cause of IDDS therapy failure. They should become an important element complementing the diagnostic strategy in patients with suspected failure of intrathecal drug administration systems. Interpretation of radioisotopic studies, since they are purely functional, must be performed in strict relation to clinical data and radiological examinations as they carry indispensable, basic information regarding morphology.

Subdural catheter migration may lead to baclofen pump dysfunction

OBJECTIVES

To report an unusual cause of intrathecal drug delivery failure in baclofen pump device.

STUDY DESIGN

A case report of an SCI patient treated with intrathecal baclofen, presenting a drug withdrawal.

SETTING

Regional spinal cord injuries centre in Geneva (Switzerland).

METHODS

We present a case of a 38-year-old male with complete T9 spastic paraplegia for 15 years, treated with intrathecal baclofen for 11 years. He recently presented to our centre with a spastic hypertonic episode, associated with rhabdomyolysis.

RESULTS

Standard investigations were unrevealing. However, a CT scan performed after injecting a radio-opaque solution by the side port of the pump, showed an unexpected catheter migration into the subdural space. Surgical revision reversed withdrawal symptoms.

CONCLUSIONS

Subdural catheter migration must be considered in the differential diagnosis of intrathecal drug delivery system failures. We recommend the use of the CT scan after contrast injection, to detect the localization of the distal catheter tip and confirm the normal diffusion into the subarachnoid space.

Imaging evaluation of intrathecal baclofen pump-catheter systems

ITB pumps are widely used in the treatment of intractable spasticity for many clinical indications, including cerebral palsy and spinal cord injury. High-dose intrathecal administration places the patient at significant risk for withdrawal in the event of device malfunction, necessitating rapid and complete evaluation of the pump-catheter system. This article reviews the approach to imaging evaluation of ITB pump-catheter systems, with specific emphasis on radiography, fluoroscopy, CT, and nuclear scintigraphy.

Review: Procedure- and Device-Related Complications of Intrathecal Baclofen Administration for Management of Adult Muscle Hypertonia: A Review

Background. Intrathecal baclofen (ITB) effectively reduces muscle hypertonia; however, associated complications influence its utility and acceptance. Objective. To systematically review the literature on procedure- and device-related complications associated with ITB infusion therapy for adult muscle hypertonia of spinal or cerebral origin. Methods. The authors searched the PubMed database for full-length articles published in English that reported ITB-associated complications in adults. Of 147 articles retrieved, 32 full-length manuscripts and 10 case reports were reviewed in detail. Results. Overall, 558 complications were reported after 1362 pump implants (0.41 per implant). Methods for characterizing complications varied greatly between studies, as did complication rates, ranging from 0 to 2.24 per implant. Of the 558 complications, 148 (27%) were related to surgical procedures, 39 (7%) to pump problems, and 369 (66%) to catheter malfunctions. The overall complication rate was higher for studies that followed patients for more than 18 months on average (mean 0.56/implant) versus studies with shorter follow-up (0.23/implant, P < .05). Although correlation between the number of implants and the number of complications was significant ( r = .58), the goodness of linear fit was poor because of clusters with varied complication rates. Conclusions. Catheter problems are relatively common and more frequent than pump or surgical procedure complications after ITB pump implantation. Higher complication rates should be expected in centers that follow patients for a longer period of time. Standardized data collection and complication-reporting procedures along with appropriate training should be implemented in centers offering ITB treatment for management of muscle hypertonia.

Indium-111 diethylene-triamine-pentaacetic acid scintigraphy in the evaluation of function and patency of baclofen intrathecal infusion systems

Object

Baclofen pump infusion systems are used for the treatment of patients with severe spasticity. When symptoms do not respond to infusion rate increases, the cause may be pump malfunction or catheter obstruction. The purpose of this investigation was to review the authors' experience with indium-111 diethylene-triamine-pentaacetic acid (In-111 DTPA) scintigraphy for evaluation of baclofen infusion system function and patency and to correlate scintigraphic findings with patient treatment and outcome to determine optimal methodology and diagnostic criteria.

Methods

Ten scintigraphic studies acquired in eight patients (five adults, three adolescents) were retrospectively reviewed. Imaging was routinely performed at 4, 24, 48, and 72 hours after injection of In-111 DTPA into the pump reservoir. The results of the studies were interpreted by two nuclear medicine physicians who had no knowledge of the patients' clinical history or outcome. The scintigraphic findings (for example, radiotracer detected in the basal cisterns, cervical or thoracolumbar regions, infusion catheter, and pump) were recorded and correlated with neuroimaging findings, patient history, treatment, and clinical response to therapy.

Results

In cases in which the basal cistern could be visualized at any time and those in which radiotracer was visualized in the thoracolumbar intrathecal region within 48 hours, the pump systems were functional and symptoms responded to an increase in infusion rate. One patient in whom activity was visualized in the thoracolumbar intrathecal region by 72 hours also experienced clinical improvement with a flow rate increase. Visualization of the pump alone or only the pump and the subcutaneous catheter was consistent with catheter obstruction or pump malfunction.

Conclusion

The use of In-111 DTPA scintigraphy of intrathecal baclofen infusion systems can play an important role in determining the functional status of these systems and guiding subsequent patient care.

Conduite à tenir devant une recrudescence de spasticité chez un patient porteur d'une pompe à baclofène

INTRODUCTION

The incidence of complications after baclofen pump implantation is relatively high. Diagnosis of these complications can be difficult. A diagnostic tree would be a useful tool in cases of suspected malfunctioning of the intrathecal bacolfen infusion system and would standardise the diagnostic procedure.

METHOD

From results in the literature and the experience of our department, we designed a diagnostic tree to aid in finding the cause of a recrudescence of spasticity in patients with implanted baclofen pumps.

RESULTS

The potential causes of recrudescence of spasticity are described and a diagnostic pathway is proposed.

DISCUSSION

The aim of a standardised hierarchical method of diagnosis of the cause of increased spasticity in patients with intrathecal baclofen pumps is to gain time in the diagnosis and treatment. Such diagnosis should improve patient care by permitting rapid restoration of an adequate level of baclofen infusion as well as decreasing the length of hospital stay and, as a consequence, the cost relating to malfunctioning pumps.

Intrathecal baclofen in the treatment of spasticity

Spasticity is a disorder of the sensorimotor system resulting in velocity-dependent increased muscle tone and tendon reflexes. Intrathecal baclofen is currently the most effective means of treating diffuse abnormal spasticity of both cerebral and spinal origin in the adult and pediatric patient. Careful patient assessment, selection and continued therapies are essential to a successful intrathecal baclofen management program. Once a patient receives a baclofen pump, close monitoring is needed for dose adjustment and pump problems. Baclofen overdose and withdrawal by either system failure or human error can cause significant side effects and be life threatening. Excellent understanding of the baclofen delivery system, programming and dose effects are needed to evaluate any patient complaints. Future uses of intrathecal pump therapy includes use of other intrathecal drugs besides baclofen (or in combination with baclofen) and the effects of placing the catheter tip at various spinal levels. At the University of Minnesota, Sister Kenny Institute and Gillette Children's Specialty Healthcare our experience has shown excellent results with this form of therapy over the last 12-16 years.

Injectable intrathecal delivery system for localized administration of EGF and FGF-2 to the injured rat spinal cord

The administration of growth factors (GFs) for treatment of experimental spinal cord injury (SCI) has shown limited benefits. One reason may be the mode of delivery to the injury site. We have developed a minimally invasive and safe drug delivery system (DDS) consisting of a highly concentrated collagen solution that can be injected intrathecally at the site of injury providing localized delivery of GFs. Using the injectable DDS, epidermal growth factor (EGF) and basic fibroblast growth factor (FGF-2) were co-delivered in the subarachnoid space of Sprague-Dawley rats. The in vivo distribution of EGF and FGF-2 in both injured and uninjured animals was monitored by immunohistochemistry. Although significant differences in the distribution of EGF and FGF-2 in the spinal cord were evident, localized delivery of the GFs resulted in significantly less cavitation at the lesion epicenter and for at least 720 mum caudal to it compared to control animals without the DDS. There was also significantly more white matter sparing at the lesion epicenter in animals receiving the GFs compared to control animals. Moreover, at 14 days post-injection, delivery of the GFs resulted in significantly greater ependymal cell proliferation in the central canal immediately rostral and caudal to the lesion edge compared to controls. These results demonstrate that the injectable DDS provides a new paradigm for localized delivery of bioactive therapeutic agents to the injured spinal cord.

Neurologische Komplikationen und Wirkverlust unter intrathekaler Schmerztherapie

In a new guideline issued by the German Association for the Study of Pain, intrathecal opioid therapy is described as proven to be effective with relatively few side effects. We reviewed this statement by analysis of the available literature and critical evaluation of the clinical course in a few of our own patients (n=3). In these cases (as well as in a further eight patients), explantation and a switch to oral opioids led to distinctly better alleviation of pain and abatement of the unwanted effects. The problems we discuss do not appear to be rare instances, but by all means complications that are frequently described. The long-term efficacy of intrathecal opioids has not been adequately verified; moreover, their potency is not high. The frequency of undesired events is comparable to that of oral opioid medication, but serious neurological complications are possible. To avoid dose escalations and to recognize neurological complications in time, diligent monitoring by the surgeon or an experienced pain center is essential.

A low-dose radioisotope procedure for assessment of subcutaneous drug delivery systems used for slow intrathecal infusion of antispasmodic agents

STUDY DESIGN

Retrospective single centre study.

OBJECTIVES

To evaluate a low-dose radioisotope imaging procedure for assessment of implanted intrathecal drug delivery and to compare the radiation dose and diagnostic value of these studies with other reported studies using higher administered radiation dose.

SETTING

National Spinal Injuries Centre, Stoke Mandeville Hospital, UK.

METHOD

A total of 11 spinally injured patients with subcutaneous drug delivery systems and uncontrolled spasm were investigated for catheter failure using a low-dose radioisotope procedure with an administered dose of radioactivity of 40 MBq Technetium-99m.

RESULTS

Loss of catheter patency was demonstrated in six patients, enabling identification of the site of blockage. Catheter patency and subsequent perfusion of CSF (ie normal result) was demonstrated in five patients. Radiation effective dose was estimated at 1.3 mSv per patient study, with a low associated risk of deleterious effect of one in 13,000.

CONCLUSION

Radioisotope investigation using a reduced administered dose of 40 MBq Technetium-99m DTPA, formulated according to a strict radiopharmaceutical protocol, provides a safe test for assessment of intrathecal drug delivery systems.

Treatment of spasticity with intrathecal Baclofen administration: long-term follow-up, review of 40 patients

STUDY DESIGN

Case series of a consecutive sample. Retrospective audit.

OBJECTIVE

To analyze the long-term safety and efficacy of intrathecal baclofen (ITB), and technical incidents.

SETTING

Neurosurgical and Physical Medicine Departments of two university hospitals in western France.

METHODS

The medical records of 40 patients who underwent ITB pump placement for the treatment of severe chronic spasticity were reviewed. Patients were eligible independently of the origin of the spasticity (spinal cord origin 33, brain damage 8). They underwent a final assessment with clinical examination and questionnaire in 2001. Ashworth scale scores were assessed, patient satisfaction was rated on a visual analog scale (VAS), functional independence before and after treatment was classified as bed-ridden, wheelchair dependent or ambulant, and the frequency and nature of complications were noted.

RESULTS

The average follow-up period was of 4 years. The average Ashworth score at the final assessment was 1.8+/-0.6. Average patients satisfaction was 7.4/10+/-2.21 on VAS. In all, 85% would have undergone the procedure again if they had to make the decision. In 85% of the cases the ambulation status was unchanged. Technical incidents occurred at least once in 37% of the patients (due to the catheter in 58% and to the pump in 42%). They included catheter disconnections (4), migration (4), kinks (3), obstruction (3), development of fibrosis (3), disconnection of pump reservoir (2), porosity of pump membrane (2), unexplained pump dysfunction (4) leakage, and subcutaneous collection (5). Severe pharmacological side effects requiring transfer to intensive care unit occurred in 12% of cases, 80% of which were directly related to pump refill procedures.

CONCLUSION

ITB remained effective in the long term and patients were satisfied. Nevertheless, complications were frequent, involving mainly the catheters, which would require further technical improvements.

Microfracture of a baclofen pump catheter with intermittent under- and overdose

An 8-year-old boy with an implanted intrathecal baclofen pump presented with intermittent signs of baclofen under- and overdose. Pump interrogation, pump volumes, plain X-rays, catheter contrast fluoroscopy and CT of the intrathecal catheter tip were unremarkable. A microfracture of the extradural catheter was only seen at a magnification of x20 and confirmed by scanning electron microscopy. Symptoms resolved following replacement. Microfracture of the intrathecal catheter of baclofen pump systems may present puzzling symptomatology and be difficult to diagnose by conventional means.

Bladder stones - red herring for resurgence of spasticity in a spinal cord injury patient with implantation of Medtronic Synchromed pump for intrathecal delivery of baclofen - a case report

BACKGROUND

Increased spasms in spinal cord injury (SCI) patients, whose spasticity was previously well controlled with intrathecal baclofen therapy, are due to (in order of frequency) drug tolerance, increased stimulus, low reservoir volume, catheter malfunction, disease progression, human error, and pump mechanical failure. We present a SCI patient, in whom bladder calculi acted as red herring for increased spasticity whereas the real cause was spontaneous extrusion of catheter from intrathecal space.

CASE PRESENTATION

A 44-year-old male sustained a fracture of C5/6 and incomplete tetraplegia at C-8 level. Medtronic Synchromed pump for intrathecal baclofen therapy was implanted 13 months later to control severe spasticity. The tip of catheter was placed at T-10 level. The initial dose of baclofen was 300 micrograms/day of baclofen, administered by a simple continuous infusion. During a nine-month period, he required increasing doses of baclofen (875 micrograms/day) to control spasticity. X-ray of abdomen showed multiple radio opaque shadows in the region of urinary bladder. No malfunction of the pump was detected. Therefore, increased spasticity was attributed to bladder stones. Electrohydraulic lithotripsy of bladder stones was carried out successfully. Even after removal of bladder stones, this patient required further increases in the dose of intrathecal baclofen (950, 1050, 1200 and then 1300 micrograms/day). Careful evaluation of pump-catheter system revealed that the catheter had extruded spontaneously and was lying in the paraspinal space at L-4, where the catheter had been anchored before it entered the subarachnoid space. A new catheter was passed into the subarachnoid space and the tip of catheter was located at T-8 level. The dose of intrathecal baclofen was decreased to 300 micrograms/day.

CONCLUSION

Vesical calculi acted as red herring for resurgence of spasticity. The real cause for increased spasms was spontaneous extrusion of whole length of catheter from subarachnoid space. Repeated bending forwards and straightening of torso for pressure relief and during transfers from wheel chair probably contributed to spontaneous extrusion of catheter from spinal canal in this patient.

Imaging in chronic spinal cord injury--indications and benefits

As most patients who have suffered spinal cord injury can now expect a normal life span, the late complications of these injuries are seen increasingly frequently. Regular surveillance of both the renal tract and the central nervous system (CNS) is important as the treatment of impending, potentially fatal complications can be implemented before damage has progressed too far. Renal tract complications are particularly dangerous as they are often clinically silent but regular surveillance to detect early deterioration in renal function, particularly from reversible causes such as reflux or obstruction can pre-empt problems. Follow-up protocols depend on the bladder management regime but most centres advocate regular ultrasound with less frequent isotope function studies. With the increasing ability to diagnose and treat the neurological complications, surveillance of the state of the spinal cord with MRI is also important and many centres now advocate checks every few years with sagittal midline T2W sections are sufficient unless changes are noted, when axial T1W sections can be added without significant examination time penalty. Imaging is critical in acute problems. In addition to suffering from the usual normal conditions, patients with spinal cord injury suffer others peculiar to, or particularly related to, the injury, which may be missed as their symptomatology is greatly altered by their paraplegic or quadriplegic status and they may often present as generally unwell but with no obvious cause. This review discusses the role of radiology in routine surveillance of the CNS and the renal tract as well as in assessing specific conditions such as deteriorating neurology or renal function, pain, spinal instability, pressure sores, ectopic ossification, muscular spasm, spinal instability, airway problems and elective operations on the renal tract.