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An intrathecal pump is a medical device used to deliver (via an intrathecal catheter) medications directly into the space between the spinal cord and the protective sheath surrounding the spinal cord. Medications such as baclofen, bupivacaine, clonidine, morphine, hydromorphone, fentanyl or ziconotide may be delivered in this manner to minimize the side effects often associated with the higher doses used in oral or intravenous delivery of these drugs.
People with spastic diplegia or other forms of spasticity, or people in intolerable pain, who cannot tolerate side effects of the higher-dose oral medications of the same medication type, are potential candidates for that medication being administered via an intrathecal pump.
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The implantable intrathecal pump consists of a metal pump which stores and delivers the medication, and an intrathecal catheter which delivers the medication from the pump to the intrathecal space in the spine where the medication takes effect. Two types of pumps are available: a constant rate pump delivers the medication at a constant rate, and a programmable pump delivers the medication according to a rate determined by a computer program.
Also external pumps, with or without a subcutaneous port are used for intrathecal delivery.
The implantable medical device requires a surgical procedure; sometimes a surgeon performs a trial intrathecal injection or implants a temporary intrathecal catheter and pump to determine if the medication works to begin with, and thus if a pump is appropriate. A permanent intrathecal pump is then implanted if the patient derives at least 50% improvement in his or her symptoms.
Intrathecal pumps require maintenance and need to be periodically refilled. How frequently this occurs is dependent on several factors, including drug concentration and dosage, and pump size. The refill frequency can range between one and six months for baclofen pumps. [2]
Intrathecal pumps periodically need to be replaced. For baclofen pumps, this may be once every 5–7 years. [3]
Spasticity is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles.
Hereditary spastic paraplegia (HSP) is a group of inherited diseases whose main feature is a progressive gait disorder. The disease presents with progressive stiffness (spasticity) and contraction in the lower limbs. HSP is also known as hereditary spastic paraparesis, familial spastic paraplegia, French settlement disease, Strumpell disease, or Strumpell-Lorrain disease. The symptoms are a result of dysfunction of long axons in the spinal cord. The affected cells are the primary motor neurons; therefore, the disease is an upper motor neuron disease. HSP is not a form of cerebral palsy even though it physically may appear and behave much the same as spastic diplegia. The origin of HSP is different from cerebral palsy. Despite this, some of the same anti-spasticity medications used in spastic cerebral palsy are sometimes used to treat HSP symptoms.
A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics. Neuromuscular blockers act by interfering with transmission at the neuromuscular end plate and have no central nervous system (CNS) activity. They are often used during surgical procedures and in intensive care and emergency medicine to cause temporary paralysis. Spasmolytics, also known as "centrally acting" muscle relaxant, are used to alleviate musculoskeletal pain and spasms and to reduce spasticity in a variety of neurological conditions. While both neuromuscular blockers and spasmolytics are often grouped together as muscle relaxant, the term is commonly used to refer to spasmolytics only.
Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is a morphinan opioid used to treat moderate to severe pain. Typically, long-term use is only recommended for pain due to cancer. It may be used by mouth or by injection into a vein, muscle, or under the skin. Effects generally begin within half an hour and last for up to five hours. A 2016 Cochrane review found little difference in benefit between hydromorphone and other opioids for cancer pain.
In pharmacology and toxicology, a route of administration is the way by which a drug, fluid, poison, or other substance is taken into the body.
Pain management is an aspect of medicine and health care involving relief of pain in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals provide some pain control in the normal course of their practice, and for the more complex instances of pain, they also call on additional help from a specific medical specialty devoted to pain, which is called pain medicine.
Clonidine, sold under the brand name Catapres among others, is an α2A-adrenergic agonist medication used to treat high blood pressure, ADHD, drug withdrawal, menopausal flushing, diarrhea, spasticity, and certain pain conditions. The drug is often prescribed off-label for tics. It is used orally, by injection, or as a transdermal skin patch. Onset of action is typically within an hour with the effects on blood pressure lasting for up to eight hours.
Spinal anaesthesia, also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic or opioid into the subarachnoid space, generally through a fine needle, usually 9 cm (3.5 in) long. It is a safe and effective form of anesthesia usually performed by anesthesiologists that can be used as an alternative to general anesthesia commonly in surgeries involving the lower extremities and surgeries below the umbilicus. The local anesthetic with or without an opioid injected into the cerebrospinal fluid provides locoregional anaesthesia: true analgesia, motor, sensory and autonomic (sympathetic) blockade. Administering analgesics in the cerebrospinal fluid without a local anaesthetic produces locoregional analgesia: markedly reduced pain sensation, some autonomic blockade, but no sensory or motor block. Locoregional analgesia, due to mainly the absence of motor and sympathetic block may be preferred over locoregional anaesthesia in some postoperative care settings. The tip of the spinal needle has a point or small bevel. Recently, pencil point needles have been made available.
Cordotomy is a surgical procedure that disables selected pain-conducting tracts in the spinal cord, in order to achieve loss of pain and temperature perception. This procedure is commonly performed on patients experiencing severe pain due to cancer or other incurable diseases. Anterolateral cordotomy is effective for relieving unilateral, somatic pain while bilateral cordotomies may be required for visceral or bilateral pain.
Epidural administration is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians and nurse anesthetists to administer local anesthetic agents, analgesics, diagnostic medicines such as radiocontrast agents, and other medicines such as glucocorticoids. Epidural administration involves the placement of a catheter into the epidural space, which may remain in place for the duration of the treatment. The technique of intentional epidural administration of medication was first described in 1921 by Spanish military surgeon Fidel Pagés.
Baclofen, sold under the brand name Lioresal among others, is a medication used to treat muscle spasticity such as from a spinal cord injury or multiple sclerosis. It may also be used for hiccups and muscle spasms near the end of life, and off-label to treat alcohol use disorder or opioid withdrawal symptoms. It is taken orally or by intrathecal pump. It is also sometimes used transdermally in combination with gabapentin and clonidine prepared at a compounding pharmacy.
Neuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system. Neuropathic pain may be associated with abnormal sensations called dysesthesia or pain from normally non-painful stimuli (allodynia). It may have continuous and/or episodic (paroxysmal) components. The latter resemble stabbings or electric shocks. Common qualities include burning or coldness, "pins and needles" sensations, numbness and itching.
Intrathecal administration is a route of administration for drugs via an injection into the spinal canal, or into the subarachnoid space so that it reaches the cerebrospinal fluid (CSF) and is useful in spinal anesthesia, chemotherapy, or pain management applications. This route is also used to introduce drugs that fight certain infections, particularly post-neurosurgical. The drug needs to be given this way to avoid being stopped by the blood–brain barrier. The same drug given orally must enter the blood stream and may not be able to pass out and into the brain. Drugs given by the intrathecal route often have to be compounded specially by a pharmacist or technician because they cannot contain any preservative or other potentially harmful inactive ingredients that are sometimes found in standard injectable drug preparations.
Tizanidine, sold under the brand name Zanaflex among others, is an alpha-2 (α2) adrenergic receptor agonist, similar to clonidine, that is used to treat muscle spasticity due to spinal cord injury, multiple sclerosis, and spastic cerebral palsy. Effectiveness appears similar to baclofen or diazepam. It is taken by mouth.
In medicine, infusion therapy deals with all aspects of fluid and medication infusion, via intravenous or subcutaneous application. A special infusion pump can be used for this purpose.
Pain in cancer may arise from a tumor compressing or infiltrating nearby body parts; from treatments and diagnostic procedures; or from skin, nerve and other changes caused by a hormone imbalance or immune response. Most chronic (long-lasting) pain is caused by the illness and most acute (short-term) pain is caused by treatment or diagnostic procedures. However, radiotherapy, surgery and chemotherapy may produce painful conditions that persist long after treatment has ended.
Interventional pain management or interventional pain medicine is a medical subspecialty defined by the National Uniforms Claims Committee (NUCC) as, " invasive interventions such as the discipline of medicine devoted to the diagnosis and treatment of pain related disorders principally with the application of interventional techniques in managing sub acute, chronic, persistent, and intractable pain, independently or in conjunction with other modalities of treatment". Medicare Payment Advisory Commission (MedPAC) defined interventional techniques as, "minimally invasive procedures including, percutaneous precision needle placement, with placement of drugs in targeted areas or ablation of targeted nerves; and some surgical techniques such as laser or endoscopic diskectomy, intrathecal infusion pumps and spinal cord stimulators, for the diagnosis and management of chronic, persistent or intractable pain". Minimally invasive interventions such as facet joint injections, nerve blocks, neuroaugmentation, vertebroplasty, kyphoplasty, nucleoplasty, endoscopic discectomy, and implantable drug delivery systems are utilized in managing subacute or chronic pain.
Neuromodulation is "the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body". It is carried out to normalize – or modulate – nervous tissue function. Neuromodulation is an evolving therapy that can involve a range of electromagnetic stimuli such as a magnetic field (rTMS), an electric current, or a drug instilled directly in the subdural space. Emerging applications involve targeted introduction of genes or gene regulators and light (optogenetics), and by 2014, these had been at minimum demonstrated in mammalian models, or first-in-human data had been acquired. The most clinical experience has been with electrical stimulation.
Intractable pain, also called intractable pain syndrome (IPS), is a severe, constant, relentless, and debilitating pain that is not curable by any known means and which causes a house-bound or bed-bound state and early death if not adequately treated, usually with opioids and/or interventional procedures. It is not relieved by ordinary medical, surgical, nursing, or pharmaceutical measures. Unlike the more common chronic pain, it causes adverse biologic effects on the body's cardiovascular, hormone, and neurologic systems. Patients experience changes in testosterone, estrogen, cortisol, thyroid hormones, and/or pituitary hormones. Both men and women require testosterone, however many doctors neglect to test women for low testosterone. Untreated intractable pain can cause death.
Peter Sean Staats is an American physician, specializing in interventional pain medicine. He is the founder of the Division of Pain Medicine at the Johns Hopkins School of Medicine, and was the Division's chief for nearly a decade. He is a past president of the North American Neuromodulation Society, the New Jersey Society of Interventional Pain Medicine,the American Society of Interventional Pain Physicians ( ASIPP) the World Institute of Pain ( WIP), The Southern Pain Society.