Intrathecal Catheter Granuloma Associated with Isolated Baclofen Infusion

Scar Tissue Catheter Tip Occlusion From an Intrathecal Baclofen Delivery: A Case Report and Review of the Literature

Intrathecal morphine is associated with the complication of catheter tip granuloma which causes symptoms of decreased pain control, increased required dose, and neurological deficit. Catheter tip granulomas from intrathecal baclofen are thought to never occur because of the mechanism by which intrathecal morphine causes granulomas. We present a case of an intrathecal baclofen induced scarring of a catheter tip with clinical characteristics similar to some symptoms of granuloma. A 66-year-old woman with multiple sclerosis induced spasticity was partially controlled with intrathecal baclofen delivery at an extremely high dose of 1638 micrograms per day. She presented in the hospital with symptoms of withdrawal from intrathecal baclofen and required an emergency revision of her baclofen pump. Replacement of the catheter demonstrated complete occlusion of the catheter tip by scar tissue. Following surgery, her spasticity was well-controlled at the much lower dose of 200 micrograms per day. Intrathecal baclofen delivery can cause catheter tip scarring which causes some symptoms similar to catheter tip granuloma. Early recognition of these signs of catheter tip occlusion could help prevent progression to withdrawal.

The Polyanalgesic Consensus Conference (PACC)®: Updates on Clinical Pharmacology and Comorbidity Management in Intrathecal Drug Delivery for Cancer Pain

INTRODUCTION

The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on using intrathecal drug delivery in chronic pain treatment. This Polyanalgesic Consensus Conference (PACC)® project's scope is to provide evidence-based guidance for clinical pharmacology and best practices for intrathecal drug delivery for cancer pain.

MATERIALS AND METHODS

Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Meeting Abstracts, and Scopus from 2017 (when the PACC last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations were based on the strength of evidence, and when evidence was scant, recommendations were based on expert consensus.

RESULTS

The PACC evaluated the published literature and established evidence- and consensus-based expert opinion recommendations to guide best practices in treating cancer pain. Additional guidance will occur as new evidence is developed in future iterations of this process.

CONCLUSIONS

The PACC recommends best practices regarding the use of intrathecal drug delivery in cancer pain, with an emphasis on managing the unique disease and patient characteristics encountered in oncology. These evidence- and consensus-based expert opinion recommendations should be used as a guide to assist decision-making when clinically appropriate.

Intrathecal drug delivery for the management of pain and spasticity in adults: British Pain Society's recommendations for best clinical practice

The British Pain Society updated their recommendations on intrathecal drug delivery (ITDD) for the management of pain and spasticity in adults. The recommendations are primarily evidence based but where necessary comprise the consensus opinion of the working group. The recommendations are accompanied by information for patients and their carers, intended to inform and support patients in their decision making. The updated guidance includes recent evidence base of ITDD use in pain and spasticity, address the issues of drug pump compatibility following the latest manufacturer and Medicines and Healthcare products Regulatory Agency (MHRA) recommendations as well as provide an update on the indications and complication management particularly endocrine complications and intrathecal granuloma formation.

Corticosteroid Therapy in Acute and Subacute Arachnoiditis - A Case Series

Arachnoiditis is difficult to treat. Patients are often left frustrated after many failed trials of conservative therapies without symptom resolution. Surgery may provide symptom relief for a short period of time, but their pain often returned. Herein, we present three cases of acute arachnoiditis following three different pain procedures: epidural blood patch, IDDS implant, and epidural steroid injection. The patients were diagnosed and treated with corticosteroids within 10 days of the procedure. Two patients were treated with the same oral steroid regiment, while the third patient was treated with both oral and IV steroid. All three patients had good outcomes at the completion of their steroid therapy. This case series may provide insight into treating acute and subacute arachnoiditis from pain interventions.

Symptomatic Intrathecal Catheter Tip Granuloma Formation With Ultralow-Dose and Low-Concentration Morphine Infusion: A Case Report and Review of Literature

OBJECTIVES

This study aimed to describe catheter tip granuloma (CTG) formation in a patient on ultralow-dose, low-concentration morphine via intrathecal (IT) drug delivery system (IDDS) and to review literature for reports of IT granuloma formation and association with drug type, drug dose, and drug concentration.

MATERIALS AND METHODS

This review describes diagnosis and management of a patient with CTG on ultralow-dose, low-concentration morphine. PubMed data base search was conducted from January 1990 to July 2021 for original articles on CTG formation in humans getting intrathecal analgesics. Data were extracted on indications for IDDS, time to detect CTG, and type of drug/s with drug doses and concentrations. Percentages and average with range for age, sex, duration of infusion, drug doses, and drug concentrations were calculated.

RESULTS

We describe CTG formation and spinal cord compression with worsening of sensorimotor deficits in a patient receiving intrathecal morphine at ultralow dose (0.6 mg/d) and low concentration (1.2 mg/mL), which is the lowest reported morphine dose associated with CTG in the literature. Our literature review shows all IT drugs have the potential for granuloma formation, and there is no drug with granuloma-inhibiting effect.

CONCLUSIONS

There is no drug, dose, or concentration that has granuloma-sparing effect. It is imperative to maintain vigilance for potential CTG in all patients with IDDS. Routine monitoring and prompt evaluation for any unexplained symptoms or change in neurologic status from baseline is critical in early detection and treatment of CTG.

Intrathecal Baclofen Monotherapy and Polyanalgesia for Treating Chronic Pain in Patients with Severe Spasticity

PURPOSE OF REVIEW

Intrathecal drug delivery is a well evidenced strategy for the treatment of many chronic pain syndromes. While opioids, anesthetics, and ziconotide are the most commonly used agents, intrathecal baclofen (ITB), which is indicated to treat spasticity, is also thought to have some analgesic properties that are poorly understood. These analgesic benefits have been reported with ITB use in treating patients with central neurological disorders who suffer from severe spasticity and chronic pain. Our review aims to characterize ITB's effects on pain, function, and quality of life in patients with severe spasticity. We performed a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. The primary outcome parameters were analgesic relief and functional improvements. Secondarily, quality of life and adverse effects were also recorded.

RECENT FINDINGS

After an initial survey identified 393 studies, 20 studies met final inclusion criteria. Of these, 16 utilized ITB monotherapy and 4 utilized ITB polyanalgesia. Overall, there was a paucity of high-powered studies. Mean titrated ITB doses ranged from 140 to 627.9 μg daily. Nineteen studies reported improved pain and spasticity. Seven studies reported improved functional outcomes and quality of life. Our results show that ITB may be an effective agent in treatingfor the treatment of chronic pain in patients with severe spasticity independent of its spasmolytic effects. Although this evidence was largely derived from studies lacking clearly defined outcomes of pain relief, ITB is reasonable to consider for concurrent spasticity and pain management. Well-designed studies are still needed to characterize ITB's analgesic efficacy when used in patients with severe spasticity.

Restoration of rostral cerebrospinal fluid flow to solve treatment failure caused by obstruction in long-term intrathecal baclofen administration

Objects: We describe five traumatic spinal cord injury (SCI) patients with an intrathecal baclofen administration (ITB) failure caused by a rostral CSF flow obstruction referred to our expert center between January 2014 and January 2019. We discuss the diagnostic workup, rostral CSF flow obstruction as the cause of the ITB failure and treatment.Methods: When we could not determine the cause of the ITB failure through the patient's history, physical spasticity examination, pump readout, absence of fluid in the pump reservoir during aspiration, or plain radiography, we performed pump catheter access port (computed tomography [CT]) myelography. When CT myelography did not reveal the diagnosis, we used scintigraphy. In an obstruction, we aimed for CSF flow restoration. In three cases, we conducted a laminectomy with microsurgical adhesiolysis. In two of these patients, we could not achieve CSF flow restoration; thus, we placed an intradural catheter bypass. Recently, in three patients, we applied a less invasive technique of percutaneous fenestration of the obstruction.Results: In one case, we performed a successful catheter replacement. In another case using surgical adhesiolysis, spasticity control was complete. In two cases, we could obtain improvement with an additional intradural bypass, followed by a percutaneous fenestration of the obstruction, resulting in further improved CSF flow restoration. In one case, percutaneous fenestration was the first line of treatment. In all cases with percutaneous fenestration, we experienced spasticity control.Conclusion: Preliminary results showed that the restoration of rostral CSF flow might result in an effective ITB treatment in patients with an intrathecal obstruction.

Intrathecal Drug Delivery

Targeted intrathecal (IT) drug delivery systems (IDDS) are well established as an effective treatment of patients with chronic nonmalignant or malignant pain, and as a tool for management of patients with severe spasticity. The risk to benefit ratio of IDD makes it a relatively safe therapy for both cancer- and noncancer-related pain, but it is not free of risks, so it should be managed at specific centers. Recent technological advances, new therapeutic applications, reported complications, and the costs as well as maintenance required for this therapy require the need to stay up to date about new recommendations that may improve outcomes. This chapter reviews all technological issues regarding IDDS implantation with follow-up and pharmacological recommendations published during recent years that provide evidence-based decision-making process in the management of chronic pain and spasticity in patients.

Subarachnoid-to-Subarachnoid Shunt for Correction of Nonfunctioning Baclofen Pump in a Severe Case of Chronic Debilitating Post-Spinal Cord Injury Spasticity

BACKGROUND

Perhaps the most disabling condition seen in patients with spinal cord injury (SCI) is spasticity. Spasticity is characterized as hyperreflexia and hypertonicity as a result of damage to the supraspinal tracts in the aftermath of SCI. Intrathecal baclofen (ITB) is the mainstay therapy for spasticity unresponsive to oral baclofen. One of the problems associated with post-SCI spasticity unresponsive to ITB is the development of scar tissue that prevents the diffusion of baclofen in the desired spinal cord area. This case offers a unique strategy to deal with multilevel scar tissue.

CLINICAL PRESENTATION

This 46-year-old paraplegic male with a T8 SCI whose spasticity had been well managed with ITB therapy for many years recently suffered intractable spasticity necessitating multiple reoperations for a nonfunctioning ITB catheter secondary to extensive scar tissue and intrathecal adhesions. Placement of a subarachnoid-to-subarachnoid shunt eliminated the problem of extensive scar tissue preventing adequate baclofen therapy.

CONCLUSIONS

After undergoing multilevel thoracic and lumbar laminectomies with subarachnoid-to-subarachnoid spinal shunt, the patient's spasticity was finally brought under control with adequate daily baclofen infusion. This case demonstrates a creative way to address ITB catheter failure before considering other measures, such as neuroablative procedures (e.g., rhizotomy, myelotomy). This case reinforces the recommendation that ablative procedures, which have far greater complications, should be reserved for patients who have failed medical or other nonablative therapies.

Intrathecal catheter-associated inflammatory mass in a neurofibromatosis type-1 patient receiving fentanyl and bupivacaine

Background:

Catheter-associated inflammatory masses (CIMs) are a rare but serious complication of intrathecal drug delivery devices. CIM formation is influenced by local medication concentration, which is determined in part by flow dynamics at the catheter tip. Underlying spinal pathologies, such as neoplasms, may alter flow at the catheter tip, thereby contributing to CIM formation. Moreover, they may also complicate the clinical and radiologic diagnosis of a CIM.

Case Description:

A 36-year-old man with neurofibromatosis type 1 presented to our emergency department with complaints of increased back pain and leg weakness. To treat pain secondary to his multiple spinal masses, he had previously undergone placement of an implantable drug delivery system, which infused a compounded drug of fentanyl and bupivacaine. Imaging studies depicted numerous masses consistent with neurofibromatosis, including a compressive mass located circumferentially at the porous catheter terminus and proximal to the catheter tip. Surgical removal of this mass was performed; pathologic findings were consistent with a catheter tip granuloma.

Conclusions:

In the described case, CIM formation likely resulted from a combination of, 1) an unusually high fentanyl concentration, and, 2) altered infusate flow due to spinal neurofibromas. Consideration of underlying spinal pathologies, particularly mass lesions, is critical to the management of intrathecal drug delivery devices.

Injury and Liability Associated with Implantable Devices for Chronic Pain

BACKGROUND

Due to an increase in implantable device-related anesthesia pain medicine claims, the authors investigated anesthesia liability associated with these devices.

METHODS

After institutional review board approval, the authors identified 148 pain medicine device claims from 1990 or later in the Anesthesia Closed Claims Project Database. Device-related damaging events included medication administration events, infections, hematomas, retained catheter fragments, cerebrospinal fluid leaks, cord or cauda equina trauma, device placed at wrong level, stimulator incorrectly programmed, delay in recognition of granuloma formation, and other issues.

RESULTS

The most common devices were implantable drug delivery systems (IDDS; 64%) and spinal cord stimulators (29%). Device-related care consisted of surgical device procedures (n = 107) and IDDS maintenance (n = 41). Severity of injury was greater in IDDS maintenance claims (56% death or severe permanent injury) than in surgical device procedures (26%, P < 0.001). Death and brain damage in IDDS maintenance claims resulted from medication administration errors (n = 13; 32%); spinal cord injury resulted from delayed recognition of granuloma formation (n = 9; 22%). The most common damaging events for surgical device procedures were infections, inadequate pain relief, cord trauma, retained catheter fragments, and subcutaneous hygroma. Care was more commonly assessed as less than appropriate (78%) and payments more common (63%) in IDDS maintenance than in surgical device procedure claims (P < 0.001).

CONCLUSIONS

Half of IDDS maintenance claims were associated with death or permanent severe injury, most commonly from medication errors or failure to recognize progressive neurologic deterioration. Practitioners implanting or managing devices for chronic pain should exercise caution in these areas to minimize patient harm.

Current and Future Issues in the Development of Spinal Agents for the Management of Pain

Targeting analgesic drugs for spinal delivery reflects the fact that while the conscious experience of pain is mediated supraspinally, input initiated by high intensity stimuli, tissue injury and/or nerve injury is encoded at the level of the spinal dorsal horn and this output informs the brain as to the peripheral environment. This encoding process is subject to strong upregulation resulting in hyperesthetic states and downregulation reducing the ongoing processing of nociceptive stimuli reversing the hyperesthesia and pain processing. The present review addresses the biology of spinal nociceptive processing as relevant to the effects of intrathecally-delivered drugs in altering pain processing following acute stimulation, tissue inflammation/injury and nerve injury. The review covers i) the major classes of spinal agents currently employed as intrathecal analgesics (opioid agonists, alpha 2 agonists; sodium channel blockers; calcium channel blockers; NMDA blockers; GABA A/B agonists; COX inhibitors; ii) ongoing developments in the pharmacology of spinal therapeutics focusing on less studied agents/targets (cholinesterase inhibition; Adenosine agonists; iii) novel intrathecal targeting methodologies including gene-based approaches (viral vectors, plasmids, interfering RNAs); antisense, and toxins (botulinum toxins; resniferatoxin, substance P Saporin); and iv) issues relevant to intrathecal drug delivery (neuraxial drug distribution), infusate delivery profile, drug dosing, formulation and principals involved in the preclinical evaluation of intrathecal drug safety.

A sheared Racz catheter in cervical epidural space for thirty months: a case report

Percutaneous epidural neuroplasty may lead to complications such as hematoma, infection, epidural abscess, meningitis, hypotension, respiratory depression, urinary and fecal dysfunction, sexual dysfunction and paresthesia. Other technical complications may include shearing or tearing, misplacement, blockage and migration of the catheter. We report a case of a 41-year-old female patient, who underwent surgical removal of a sheared catheter, which was retained for 30 months after cervical Racz neuroplasty.

Increased spasticity from a fracture in the baclofen catheter caused by Charcot spine: case report

In patients with Charcot spine, a loss of normal feedback response from the insensate spine results in spinal neuropathy. Increasing deformity, which can manifest as sitting imbalance, crepitus, or increased back pain, can result. We present the case of a patient with a high-thoracic spinal cord injury (SCI) who subsequently developed a Charcot joint at the T10-11 level that resulted in a dramatic increase in previously controlled spasticity after fracture of an existing baclofen catheter. The 68-year-old man with T4 paraplegia presented with increasing baclofen requirements and radiographic evidence of fracture of the intrathecal baclofen catheter with an associated Charcot joint with extensive bony destruction. The neuropathic spinal arthropathy caused mechanical baclofen catheter malfunction and resulting increased spasticity. The patient was found to have transected both his spinal cord and the baclofen catheter. Treatment consisted of removal of the catheter and stabilization with long-segment instrumentation and fusion from T6 to L2. Follow-up radiographs obtained a year and a half after surgery showed no evidence of hardware failure or significant malalignment. The patient has experienced resolution of symptoms and does not require oral or intrathecal baclofen. This is the only reported case of a Charcot spine causing intrathecal catheter fracture, leading to increased spasticity. This noteworthy case suggests that late spinal instability should be considered in the setting of SCI and increased spasticity.

Spinal cord compression secondary to intrathecal catheter-induced granuloma: a report of four cases

Objective: The management of nonmalignant pain by morphine pump implantation has become an effective and increasingly frequent strategy of care. We report a rare complication of intrathecal granuloma formation adjacent to the intrathecal catheter tip resulting in spinal cord compression in four patients undergoing intrathecal treatment for chronic pain.

Methods: Four patients presented with chronic back pain and lower extremity pain and weakness and were treated with morphine pump implantation (Fig 1). Each patient developed a mass at the level of the intrathecal catheter tip resulting in increased back pain and diminished neurological function. Following clinical examination and x-ray workup, the patients underwent surgical resection of the mass and removal of the intrathecal catheter. One patient received conservative saline therapy first, and another patient had granuloma resection first and removal of the intrathecal catheter at a later date. Pathological analysis showed granulation tissue with extensive necrosis and chronic inflammation, with negative culture results. No evidence of neoplasm was found.

Results: Patients showed varying degrees of improvement following removal of the intrathecal mass. Two patients had moderate pain reduction following resection of the granuloma; a third had minimal pain improvement; and a fourth had significant pain improvement but continued lower extremity weakness.

Conclusions: The formation of granulomas caused by intrathecal catheter implantation is a rare but serious complication. Imaging studies including magnetic resonance imaging with contrast and computed tomography with myelogram should be used to follow up a neurological examination consistent with spinal cord compression. Timely surgical intervention may result in marked improvement of symptoms.

Polyanalgesic Consensus Conference 2012: recommendations for the management of pain by intrathecal (intraspinal) drug delivery: report of an interdisciplinary expert panel

INTRODUCTION

The use of intrathecal (IT) infusion of analgesic medications to treat patients with chronic refractory pain has increased since its inception in the 1980s, and the need for clinical research in IT therapy is ongoing. The Polyanalgesic Consensus Conference (PACC) panel of experts convened in 2000, 2003, and 2007 to make recommendations on the rational use of IT analgesics based on preclinical and clinical literature and clinical experiences.

METHODS

The PACC panel convened again in 2011 to update the standard of care for IT therapies to reflect current knowledge gleaned from literature and clinical experience. A thorough literature search was performed, and information from this search was provided to panel members. Analysis of published literature was coupled with the clinical experience of panel members to form recommendations regarding the use of IT analgesics to treat chronic pain.

RESULTS

After a review of literature published from 2007 to 2011 and discussions of clinical experience, the panel created updated algorithms for the rational use of IT medications for the treatment of neuropathic pain and nociceptive pain.

CONCLUSIONS

The advent of new algorithmic tracks for neuropathic and nociceptive pain is an important step in improving patient care. The panel encourages continued research and development, including the development of new drugs, devices, and safety recommendations to improve the care of patients with chronic pain.

Intrathecal drug delivery system (IDDS) for cancer pain management: a review and updates

Cancer pain remains undertreated and a significant number of patients with cancer pain die from severe untreated pain. With increasing survival rate in cancer, the prevalence of cancer pain is also increasing in number. Though majority of patients with cancer pain can be effectively treated with conventional medical management, still a significant portion of patients required some form of interventional pain management techniques. Among the interventional techniques, intrathecal drug delivery is increasingly used in cancer pain management. Our objective of this article is to review literatures and clinical studies on intrathecal drug delivery system (IDDS) in cancer pain management and to provide updates on its use, precautions, contraindications, side effects and its management, socioeconomic consideration, and management of IDDS in difficult or uncommon situations.

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.

Catheter-tip mass mimicking a spinal epidural hematoma

As > 95,000 spinal drug-delivery devices have been implanted since their inception in the 1980s, the recognition of associated adverse effects is essential. Since 1985, numerous reports have described the presence of catheter-tip granulomas. In the current case, the authors describe a less frequent complication of epidural bupivacaine precipitation. Regardless of origin, these unusual lesions have been increasingly recognized as a rare but potentially devastating complication of intrathecal infusions.

A 34-year-old woman with an intrathecal pain-pump delivering fentanyl, bupivacaine, and clonidine for thoracic outlet syndrome presented with rapidly progressive neurological deficits and increasing neck and upper-extremity pain. Neuroimaging disclosed a C7–T1 mass that was thought to be a hematoma that occurred after a recent epidural steroid injection. On emergency surgical decompression by laminectomy, a chalky mass containing viscous fluid was identified surrounding an epidurally located catheter. Histopathological examination revealed a proteinaceous mass consistent with drug precipitate enveloped by fibrosis and mild inflammation. Postoperatively, the patient recovered with minimal neurological deficit. The presentation and clinical relevance are discussed in conjunction with a review of the pertinent literature.

Catheter-tip masses are a rare complication of implantable drug-delivery devices occurring in < 3% of all patients with intrathecal catheters. Regardless of the anatomical site, the most common presenting features are neurological deficits, worsening pain, and increasing requirements for pain medication. Expedient diagnosis and management are essential for physicians treating patients with spinal infusion devices to prevent significant neurological sequelae. Further investigation is warranted regarding the use of bupivacaine as an adjunct in permanent spinal infusion systems.

Normalization of central cord syndrome spinal cord injury urodynamics after intrathecal baclofen therapy: a case report

Objective. To report a case of improved urodynamics in a central cord syndrome spinal cord injury after intrathecal baclofen therapy. Methods. A 47-year-old man fell resulting in C4-C5 disc herniation with ventral spinal cord compression and cord edema. Results. He underwent an anterior cervical discectomy and fusion. Postoperatively, his examination revealed a C4 ASIA D injury in a central cord syndrome pattern. Cystometrogram (CMG) revealed a hyperactive detrusor with sphincter dyssynergia managed with intermittent self-catheterization. One and a half years later, he was impaired by severe lower limb spasticity, despite oral medications and botulinum toxin injections. After intrathecal pump therapy, CMG revealed relatively normal detrusor and minimal sphincter tone. He volitionally voids with urgency but improved continence, which was maintained in one-year follow-up. Conclusion. Although the main indication for intrathecal baclofen therapy is spasticity, improved urodynamics can be an additional benefit in central cord syndrome spinal cord injury.

Long-term intraventricular baclofen infusion in beagles

OBJECT

This study was designed to evaluate the clinical and histopathological effects of long-term (3-month) intraventricular baclofen (IVB) infusion in beagle dogs.

METHODS

Catheters were inserted stereotactically into the lateral ventricles of nine dogs and were connected to implanted Synchromed II pumps. Saline solution (control animals) and IVB (experimental animals) were infused continuously. The IVB dosages ranged from 100 to 1000 microg/day.

RESULTS

An IVB infusion of 135 microg/day or less throughout a 3-month period was associated with no adverse side effects in any animal. Infusion of 150 microg/day produced overt seizures in one dog and produced adverse side effects in another; a reduction in the dosage given to these animals to 135 microg/day was tolerated with no adverse effects. Infusion of IVB at a dosage of 250, 500, or 1000 microg/day caused lethal toxicity within the first 4 days of infusion. Histopathological specimens obtained at necropsy revealed no ventricular or subependymal changes in animals receiving an IVB dosage of 135 microg/day or less.

CONCLUSIONS

Intraventricular baclofen infusion in beagles has dose-related toxicity; however, no clinical or neurological toxicity was evidenced at clinically tolerated dosages (< or =135 microg/day) throughout 3 months of infusion.

Intrathecal baclofen for childhood hypertonia

INTRODUCTION

Intrathecal baclofen was first introduced in 1985 to manage childhood hypertonia. There has been an evolution in thought as to how candidates should be identified and what forms of hypertonia respond to this treatment.

PURPOSE

This manuscript reviews the pharmacology of the drug, the assessment of candidates, the implantation of the infusion pump, and the usual doses delivered. Side effects and complications are reviewed as are outcomes.