July 04, 2012
- Hello ladies and gentlemen and thank you for joining us. The following session is a three part talk and discussion. Number one regarding selection of a proper surgical candidates for treatment of cerebral palsy hypertonicity or spasticity. The second talk will be technical nuances for implantation of a drug infusion pump. And the third talk will be a talk regarding how to troubleshoot the synchromed pump. Dr. Michael Turner one of my dear friends and colleagues from Goodman Campbell Brain and Spine is the discussant for all the three talks. Again, thank you for joining us.
- Hello, I'm Dr. Michael Turner. We have a three-part series on the management of hypertonicity and in cerebral palsy and other problems primarily with the use of intrathecal baclofen. The first talk will be more on patient selection and historical surgical approaches to cerebral palsy and hypertonicity. I do receive honorariums for teaching and consulting as well as research from Medtronic. Also Medtronic has not reviewed edited or approved this talk and they discuss procedures or uses for intrathecal baclofen that are not in the FDA labeling for baclofen. I am sharing personal experience and not making any recommendations on behalf of Medtronic. Movement in hypertonicity it's not spasticity anymore. I think one of the things that I've learned over the years is that spasticity what was called spasticity in the 1980s when we started doing surgical treatment for spasticity has now become much more divided into other specific types of spasticity. But one of the things that helps me understand movement is a simple idea of closing your eyes and touching your nose. And then think about yourself as a robot engineer trying to design that program that will very fluently take your fingertip with your eyes closed with no visual input and be able to very smoothly touch your nose. If you think about it that requires the flexion and relaxation of multiple muscles across multiple joints. And to do that there has to be sensory feedback and that uses a combination of motor tracts cortical spinal tract, supplementary motor areas rubro spinal tract and other tracts such as that. Sensory feedback along the spinal thalamic and coordination of the agonist antagonist muscles which has done often at the spinal cord level. And this is done through the use of feedback loops within the brain. And so some of these feedback loops are stimulating loops. Some are inhibitory. And when there's damage to the brain that affects movement in many ways not just causing spasticity. If you do injure the central nervous system you do get a number of effects including weakness but also loss of fine motor movement loss of sensation, loss of coordination loss of integration and creation of parietal difficulties with dressing and other movements. You got visual spacial abnormalities and then you have increased tone or hypertonicity. Classically, there are types of hypertonicity that have been described. The first one is classic spasticity and this is a velocity dependent increase in the stretch reflexes that's part of the upper motor neuron syndrome. It may be accompanied by clonus and spasm. What that means is with a spastic limb when you slowly move it you can extend it completely. However, if you try to do it rapidly it locks up and the faster you try to move it the quicker it locks up. And this is called spasticity. There's also hyperactive reflexes and clonus with that. Dystonia on the other hand is a movement disorder characterized by sustained muscle contractions usually producing twisting and repetitive movements or abnormal postures. And you can have a very stiff hypertonic arm that could be confused for spasticity except it is not velocity dependent. No matter how fast you move it fights you just as much. Also dystonia can be the classic cervical dystonia where there's tonic contraction of the neck. And it can be also atonic of contraction of any of the extremities. Athetosis is an involuntary slow writhing rising movements that essentially flow one into the other. Often, this is associated with chorea another related condition with involuntary rapid irregular jerky movements. Although the athetosis may be most prominent in the face neck, tongue and hands it can affect any muscle group. Classically, it's associated with neurodegenerative diseases primarily Huntington's and Wilson's disease as well as some types of cerebral palsy. It may also result from infections involving the brain. Rigidity is a classically related to Parkinson's disease. It's a severe stiffness and resistant to movement both flection and extension. And again, is felt to be a Parkinsonian type of syndrome. Again, just to emphasize the number of tracts involved with movement. In the motor tracts descending you have all of the descending cortical spinal tracts and rubro spinal tracts reticulospinal tracts and then you have the sensory tracts going up, as well in every patient coordinating a simple movement. Pure upper motor neuron spasticity is a lesion to the upper motor neuron. We see this in spinal cord injury mild cerebral palsy, multiple sclerosis and mild stroke. Mini brain injuries, however, more extensive involve lesions down in the basal ganglia. However many brain injuries are much more extensive and have involvement of those feedback loops which are in the basal ganglia. Classically, this is a grade four interventricular hemorrhage in a premature infant or classic basal ganglia hyper hypertensive hemorrhage and these cause much more complex problems. The old thoughts we used to say that all increased tone with spasticity. We now know that increased tone can be dystonia can be rigidity. It can be spasticity. We used to think that rigidity only occurred in Parkinson's but we now know that it's very common in severely brain injured children. And the only cause of athetosis was kernicterus. And again, we're seeing more and more children with some athetoid syndromes. We learned a lot from selective dorsal rhizotomy. That was the first surgical procedure that was relatively effective in cerebral palsy. And when all you have is a hammer everything looks like a nail. And we would do just about any child with hypertonicity. We would do a selective dorsal rhizotomy whether they were quadriplegic or what their etiology was. And we would find recurrent spasticity in a group of these patients. And primarily these were the more involved spastic quadriplegic cerebral palsy kids. And it would come on four, five, six, seven years after their rhizotomy. And they will have definite recurrent increased tone but it was not velocity dependent. There was no hyperreflexia and that's because this was dystonia and the selective dorsal rhizotomy did not do much for dystonia. Again, the spastic quad cerebral palsy kids have those grade four hemorrhages that get into the supplementary motor areas and you get a mixed movement disorder. However, spastic diplegia is caused by periventricular leukomalacia or PVL. And that's a very subtle lesion in the ventricular walls which just gets the cortical spinal tract as it comes down into the through the internal capsule. And the leg fibers are much closer to the ventricle than the arm and that's why they have isolated and more severe movement problems in the lower extremities. And again, these supplemental motor areas in the basal ganglia along the lateral ventricle, the hippocampus the corpus callosum all of these areas play a role in movement. So if you're going to want to intervene in spasticity or hypertonicity what criteria do you need? First, you needed the hypertonicity is interfering with the functions of daily living. So are they having spasms loss of range of motion moment pain, impaired ambulation difficulty just sitting in a chair? And of course when you have severe Ad ductors tone in the legs it's very hard to get the legs apart to do basic hygiene. The most important thing to achieve good outcome is to make sure that the patient and their caregivers functional goals are the same as yours. Very important part to remember is the goal is never spasticity reduction or tone reduction. Patients never come in and say my Ashworth score is too high. What they want to do is have a functional improvement. And the reduction of the tone is the tool we're using to achieve that intervention and achieve those goals. Ambulatory patients are much more difficult to intervene because they use their spasticity to brace their knees when they ambulate. So as you reduce the spasticity they will develop weakness in their knees and their quads and have difficulty standing. And this can significantly impair their ability to ambulate. And so you have to either titrate the tone control or be very careful in patient selection. So what have we done to try and treat hypertonicity especially in cerebral palsy? Probably the first thing that was intervened was cerebellar stimulation done in the early seventies and eighties. The idea behind it was to increase the inhibitory output from the deep nuclear, the cerebellum the rubro spinal denticular spinal tracts which are known to be inhibitory tracts. It seemed to work but apparently did not have enough effect for functional improvement. Now, the selection criteria were not for patients were not well identified and the procedure has pretty much been abandoned. Bischoff's Myelotomy where coronal incisions in the gray matter of the spinal cord which would disconnect the anterior neurons from the posterior sensory input. This was the monosynaptic stretch reflex that disconnects it. It has a potential for some weakness and incontinence. It is very effective but really has fallen out of favor recently because most patients in the stem cell research era do not want to have their spinal cord cut for fear of preventing further improvement with stem cell or other surgical procedure. Percutaneous radiofrequent rhizotomies were done again back in the seventies and eighties. And this is where a radio frequency probe was placed percutaneously into then Neuroforaminal and the postganglionic route was heated. There was selective destruction of the smaller and more heat sensitive sensory rootlets. It seemed to be very effective was very easily tolerated but unfortunately the tone would return in a few months. People obviously have done anterior rhizotomy where you cut the motor root. This is effective, but obviously causes severe weakness. And it has to be done in patients with severe dense pre-existing deficits. Most important, it leads the really severe atrophy and flaccidity and there's a high incidence of skin breakdown over bony prominences when this is done. And it's again, it's been pretty much abandoned. Now, selective dorsal rhizotomy Sherrington in the 18th century or 17th 19th century realized that cutting poster routes in cats reduced spasticity. Foester in 1913 would section the posterior roots and show that actually worked as well in humans with hypertonicity in spasticity. Total section led to loss of sensation and proprioception and a significant impairments from that. A number of other Italians tried random partial selection of routes with success. Fasano in 1977 and 78 used EMG testing to attempt to identify populations of sensory root serving overactive loader more neurons. And these can be identified by intra-operative stimulation and section. Peacock in 1982 modified the procedure identified the best candidates and did long-term followup on his patients and published them and popularized the procedure. The idea behind the monitoring is to place EMG electrodes on the lower extremities of the patient. Surgical drapes are positioned to allow observation of lower extremities during the procedure. And then the patient is placed in the routine laminectomy procedure position. The classic is to do a laminectomy of L1 to S1. Dr. Park in St. Louis has a variant using L1 to L2 laminectomy right over the conus. You preserve the lamin in both procedures open the dura preserve the rachnoids as well as can happen and in the classic identify the roots at the exit to the neuroforaminal. Park uses his EMG to identify the roots at the conus. We identify and separate the anterior from the posterior root and then divide the sensory root into rootlets and then test the individual rootlets with EMG stimulation. You first identify the stimulation threshold and then you get a one-second 50 hertz train of stimuli. Decrement is normally seen. Spread to other limbs or other routes is considered abnormal. And failure of decrement is considered abnormal. You section the abnormal rootlets average about 50%. Now, over the ages people have noted more and more of that the EMG monitoring can be have variable results. The classic tests where, excuse me when a surgeon actually labeled every rootlet tested it, put it down went to the other side test, labeled and tested the other side came back to the first side and the concordance of the results was really quite poor between the two times when the roots were tested. Also, most of us who have done this found that you can change the outcome by how much pressure intention you put on the roots when you test it. And many people have have gone to non-selective rhizotomy and I've done that as well. And the outcome seems to be as good as long as you tailor your decisions pretty much to the root. So we test L2 to S1 bilaterally. I avoid S2 because that causes the toe curl but it also may be involved in bladder sensation. And we do not do L-3, S3 and S4 because of bladder sensation. We tend to cut more rootlets at S1 less at L4 because trying to get better reduction in tone in the ankle and foot and try to preserve strength at the quadriceps. We then closed the dura replaced the lamina and closed the wound. Postoperative care pain control we use epidural narcotics with marcaine. I put them in the ICU primarily to have a nurse whose sole job is to make sure this child has good pain control. They're flat in bed for 48 hours. On day three we elevate the head wean the epidural and start therapies. By day six they're in a full rehab program op-ed lib and taking Tylenol for pain. The ideal patient is three to six years old before they've ingrained too many bad movement patterns. The classic has a premature is a premature child with normal cognitive function spastic diplegia cerebral palsy no previous autho lane, soft tissue procedures that would cause a weakness because of tendon lengthenings and muscle lengthening. The spasticity is impeding progression of function primarily ambulation and they have to have adequate underlying strength adequate strength. They have to be ambulating in a walker. At least they can get into their walker on their own power. They can do maneuvers in physical therapy called tall kneeling where they stand tall while on their knees. Side sitting is a great way. They tuck their knees on one side and then sit up straight. This evaluates the amount of truncal in core strength that they have. It's very good if they have isolated movements in their knees and ankles. And even even better in the toes. And most important can they do a gradated squat? Where they have their hands on a wall slide down the wall bending their knees. When they get halfway down they can turn around and stand up. If they have those qualities they're likely to be a very good candidate for a rhizotomy. We tend to do older children if they're having significant functional improvement significant improvement is possible. Contraindications children with dystonia, significant dystonia rigidity or athetosis. Those who are too weak underneath and those that are uncooperative in rehab. In the spine spondylolysis, scoliosis and kyphosis was feared. CP with rhizotomy is about the same with these as a CP kid without rhizotomy. There were early on when we were doing more impaired children there were some respiratory problems but no longer are considered to be ideal candidates for rhizotomy. And they tend to get baclofen pumps. Sensory dysesthesias are transient in about 40% and permanent interfering sensory loss in less than 1%. Bowel and bladder function loss is transient in rare. Many have significant improvement in their their bladder control and potty training because they had a quite a spastic bladder. Permanent problems have been reported to be less than .1%. All of the patients are weaker initially. Permanent paralysis from a postoperative complication has not been seen in cerebral palsy kids but they may lose their ability to ambulate. With poor selection, they were too weak pre-operatively. Spasticity is reduced in the children increased joint range of motion in stride length but patient selection is important. Other procedures done are deep brain stimulation. This has been used in dystonias. Bilateral pallidal deep brain stimulation gives 50 to 60% improvement in generalized dystonia. The DYT1 mutation can have results in about 90%. Often, it can take four to six weeks of stimulation to begin to see improvement. Intrathecal baclofen has been available for treatment of hypertonicity since 1992. And it's approved by the FDA for treatment of spasticity in cerebral palsy, stroke multiple sclerosis to Braddock brain injury and spinal cord injury. A pump and catheter implanted into the patient and there is a control or patient programmer that through the skin can alter the doses. Indications for intrathecal baclofen include spasticity of spinal origin spinal cord injury, including trauma tumor, or stenosis multiple sclerosis. Hereditary conditions such as hereditary spastic paraparesis. Also spasticity of cerebral origin including multiple sclerosis, brain injury cerebral palsy and stroke. In severe TBI we have a child here with a quite severe TBI. They can have severe and marked impairments. They can not be seated cleaned, ranged, and intrathecal baclofen allows earlier functional rehab. And those of you who don't we talked about rigidity those of you who have seen children like these know you cannot bend these extremities at all. So they're really not the classic spastic. They're more rigid. And most TBI patients have a mixed etiology for the hypertonicity. We'll go to a video here. This is a three-year old we took care of back in 2001. She was injured on the 4th of July. This is being filmed on July 31st. And those of you in pediatrics will see this. This is an anoxic injury. Actually, she had her head caught in the an old SUV back window and it took about four minutes to break and get her free. And this is her in rehab at three weeks following that injury. She is op-er stodnick. She's also has a autonomic storming with temperatures of 104. Her pulse rate up over 200. Sweating profusely in spite of being on multiple medications for this including alpha blockers, beta blockers bromocriptine, benzodiazepines chloral hydrate and she still looked like this. We did a baclofen testos and eventually implanted a baclofen pump in her. And this is her in October which is about four months later. Immediately after putting the pump in we stopped the storming. We were able to bend her get her seated and actually she went home a couple of weeks later. She continues in rehab. And eventually I saw her back in 2009 and we took her pump out. We were able to wean her baclofen down took her pump out. She is attending school. She has some special classes. She doesn't talk but motor is really quite good. Here she is going to wave to me. So this is a child who had her pump placed within a month of her you can stop within a month of her injury and has made a very good recovery with a baclofen pump. Typical cerebral palsy patients goals for the severe one again are hygiene, range of motion preserving hip joint integrity just getting the kids to be able to seat. Getting a child into a wheelchair gives him great freedom and cuts down the cost of care significantly. Also allows better transfers. In mild, the goals are really have to do with improving ambulation, stride length, and cadence. There was some worry about scoliosis being increased. There's some recent in case control studies that show that in general children who need fusions who get baclofen pumps will still require a fusion. No child who wasn't whose case control did not require a pump required a fusion required a fusion getting a baclofen pump. In multiple sclerosis is a progressive disease. The use of intrathecal baclofen can maintain function much longer. Very good research done by Dr. Bertow at the Cleveland Clinic has shown very clearly that if a patient has a pump early in their loss of function they will maintain independently and stay out of totally dependent care much longer than if they didn't. And for very similar goals for non-ambulatory patients are decreased spasms, decreased pain increased range of motion ease of hygiene, and better transfer. Very important that a patient that has deteriorated to a barely ambulatory state. In other words, a patient comes in asking for a pump who can barely walk in a walker. If you put a pump in them you will make them they will no longer walk because they're using their tone to ambulate. And wiping out their tone will wipe out their gait. ITB cannot improve gait when the patient's major gait problem is weakness. The other thing to remember about ambulation that the improvement is slow. You can decrease tone only gradually to allow strength to build up and then you can increase the pump dose some more and decrease spasticity more as they get stronger. And often at six to nine months after intent plantation of the pump before the patient reaches a stable dose and significant improvement. And obviously the ambulatory goals are to improve stride length, endurance, balance. And this is often achieved by getting rid of the scissoring gait. Decreased spasms and improved isolated motor movement. Stroke is often a mixed cerebral injury. There's motor and supplementary motor area involved can have mixed hypertonicity. The goals are all since many of the stroke patients who come to you are ambulatory the goal is often to improve the ambulation. Improved isolated motor function. Many of them have the classic clasped fist and flexed elbow and getting that range out of getting the hands open significantly improves the quality of life. And adults with stroke, again many of them are on anticoagulation which is a significant co-morbidity. And obviously a stroke is a sign of cerebral vascular disease. And many of these have co-existing difficulties with cardiovascular disease. The important thing in spasticity is the good side in all the studies has not been made weaker. So you can reassure the patient that the good side won't get weaker. It's very important when evaluating stroke patients is to determine if the difficulty with their tone is due to weakness or is it due to increased tone. And it's very important to identify that if it's too confusing often the baclofen test dose will help sort that out. Complications of baclofen. The overdose the pump never goes crazy and overdoses the patient. Programming errors can lead to overdose. There are underdone difficulties including a severe withdrawal syndrome which we'll address in a later talk. What other complications? Medtronic maintains an ISPR file which is a group of centers that keep phase three study type of data with study coordinators at multiple centers doing both pain and spasticity. And in them in the pumps that have about a five to 10% infection rate among the multiple centers. Catheter failure is 10% at four years. 20% at eight years. Premature pump failure is less than 1% at four years. 5% at six years. And all of the pumps have an end of service life of seven years. And will shut off at seven years. So when we talk about rhizotomy versus ITB for the patient with cerebral palsy a rhizotomy does reduce spasticity but the reduction is permanent and not titratable. It's a much bigger operation upfront but no further operations through the patient's life. No further treatment after recovery other than severe or significant physical therapy. Initially there is weakness especially in the quads that require intensive physical therapy to overcome but you get excellent results in properly selected patients. Baclofen does reduce spasticity as well but it is titratable. It is only a one to two hour operation but it has to be repeated every seven years. And obviously you have to the patient has to come in at least every several months for fills and adjustments. But again, you get excellent results in correctly selected patients. This is a patient of mine who came from Atlanta because of recurrent catheter problems. I did not install her pump initially. As you can see she has all of the things that we would call spasticity. She has up on her toes. Once she gets down the stairs you can see that her she's very, very narrow gait. She has classic scissoring. Classic crouch gate that we see in spasticity. You see that her hands are fisted and her elbows are flexed. When she sits you'll see down her toes are tonically flexed. And this is when her pump is not working. And you can see that she again has much difficulty dressing. Here, you can see her coming down the stairs and again requires a lot of strength. Crutched for balance because again, her she has such a narrow stance and up on her toes that she really can't balance herself. She has very a narrow gait. And again, that crouch flexed at the hips, bent at the knees and crouch gait. This is a patient we would have called a spastic cerebral palsy. She does not have cerebral palsy. She has an acquired mitochondrial disorder. Now notice when her pump is working she has an absolutely normal gate. She has no weakness. She has no underlying upper motor neuron disorder because she is not spastic. She was dystonic. And she had the tonic contraction due to dystonia. Although again, had all the hallmarks and many of the signs we see in spasticity but without an upper motor neuron lesion she has normal fine motor movement. She can tire shoes easily put her, dress very easily. Her strength is normal. And again, when we see her walking we'll see that her stride length is normal. She does not require a crutch. She has normal stride length. She has a normal stance and can walk with a very nice heel toe strike. She again has a normal gait. Part of the message from this is many things that we've called spasticity in the past are truly not spasticity. And as we become more sophisticated we really have identified these children to have dystonia or other lesions. And that within you don't have to have a upper motor neuron lesion to mimic many of the signs. Thank you for listening. The next program will be on implantation in the nuances of technique and implantation the synchromed pump for intrathecal baclofen. Thank you very much.
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