Phenol: An Update
A conversation between Howard Thiel and James A. Auberle, M.D., neurologist, Toledo Clinic, Toledo , Ohio :
Q.) Dr. Auberle, I would like to, on behalf of all of the people afflicted with ST, ask you a series of questions. They are not intended in any way to put you on the defensive or to make the application look bad. Rather, they are intended to explain what Phenol is, the side effects, the success or failure of it, etc.
A.) Yes, I would be happy to answer questions concerning the use of phenol in ST.
Q.) What is Phenol? What was it meant to do? What other conditions is it used to treat?
A.) The term "phenol" can be used to refer to a specific basic chemical structure. Unfortunately, it also refers to a general class of similar substances with variations of the basic chemical structure. It is found in nature; however, various chemical processes in a laboratory easily synthesize it. Phenol has been used in the medical field for almost half a century. It does its job by denaturing protein. Examples of other denatured proteins include curdled mild or cooked scrambled eggs. For our purposes, when it comes into contact with nerves or muscle, those areas stop working in a normal fashion. It has been primarily used for nerve blocks and the treatment of spasticity.
Q.) Is it FDA approved?
A.) Phenol is not approved by the FDA for the specific treatment of ST. Phenol was used in medical circumstances prior to the formation of the FDA. Another drug that may also be considered in a similar situation is aspirin. Aspirin is also not specifically approved by the FDA for the treatment of ST either. Botox Ò or botulinum toxin has only recently received its approval in dystonic conditions, e.g. spasmodic torticollis. However, given the length of time that phenol has been around, and if it were to cause serious problems, the FDA would have acted by now in restricting its availability.
Q.) How long has it been around? And, as it was used for the treatment of Spasmodic Torticollis in the 40's, why was it discontinued, and why is it being "resurrected" now? Is your mode of treatment different?
A.) The earliest reference that I have states that the use of phenol began in the late 1940's and 1950's for the treatment of spasticity. This is a condition similar to dystonia and at various times it may be difficult to distinguish the two disorders. It is unclear why phenol did not remain popular. I do not believe that phenol was actually used in the treatment of ST per se. Also at that time, ST was still unfortunately considered a psychiatric illness. There are several methods of injecting phenol. It may be injected into the spinal cord, at a root level, plexus, peripheral nerve, motor point, or into a muscle. I have used the injections for conditions of increased tone (spasticity, or dystonia). Our most common site of injection is at the terminal portion of the nerve where it meets muscle otherwise known as the motor point.
Q.) Do you inject into the muscles? In the nerves? Do you use an EMG? What EMG?
A.) The motor points are the places where the nerve enters into the muscle. These are the best locations to perform the injections. Unfortunately, they can be very difficult to locate and may require extra time in searching for them. Some physicians may use electrical stimulation to better help identify these specific areas. Because these areas are not easily found, I attempt to use the electrical stimulation and EMG to better identify the best sites for injection. The EMG machine that we use is a computer-based system with 8 channels to record muscle activity. It has been referred to as the "big EMG" versus those systems that provide only sound.
Q.) How much is injected? Are there different amounts that can be injected?
A.) The amount of phenol that is injected is 0.25 cc to 3.00 cc depending on the muscle activity that is recorded. We use a 5 % solution of phenol in sterile water. The literature on this topic describes concentrations of 2 % to 10 %. We settled on 5 % because it seemed to be the most common dilution, easy to work with, and easy to prepare. Stronger concentrations than 10% would eat away at the little rubber stoppers on the vials!
Q.) How many patients have you injected?
A.) The original pilot study was performed on eight patients. One of the patients dropped out because of a time commitment. The original group was required to be evaluated every two weeks. With the reasonable success that was met there, we continued to pursue phenol injections as an alternative form of therapy for ST.
Q.) Do you know that Dr. Janice Massey has pioneered this "resurgence" of Phenol? Do you correspond with her?
A.) I believe that much of the credit for this work should go to Dr. Massey. It was through the local grapevine that I heard of the work she was doing at Duke University after some information had "leaked out" that she was using phenol for ST treatment. It seemed a logical alternative form of treatment for patients that may have been resistant to treatment with botulinum toxin. I have had the opportunity to speak with her regarding the use of phenol in treatment of ST. Much of what we do is in many ways similar, although apparently I tend to use smaller amounts of medication.
Q.) What happens when Phenol is injected? What does it do? We have heard via the rumor mill that it destroys anything that it is injected into. Is this true? If this is true, what happens if you miss the site of injection? And, if this is true, why do you have to back for further injections?
A.) When phenol is injected, the area that it invades locally becomes denatured. It does not spread throughout the muscle like botulinum toxin. Since most of us are made up of patterns of proteins, when these are disrupted, then things don't work as well. For the most part, whatever it comes into contact with it destroys. If an injection misses the motor point, then a small area of muscle stops working. However, ideally, because we are injecting muscles that are dystonic or overworking, that small a decrease may not cause the patient to notice any significant change. In spite of all the care to destroy the terminal portion of a nerve in a dystonic muscle, over time the nerve may grow or regenerate back to its original situation. Therefore, once stabilized, repeated injections will probably be required at periodic intervals for this form of therapy.
Q.) Are there short term side effects and, if so, what would they be?
A.) There are very few side effects with our motor point method since small amounts of phenol are used, the most significant of which is that the phenol causes more discomfort than other injections e.g. botulinum toxin. It may also have a tendency to cause the muscle to spasm during or shortly after the injection. Some dizziness or lightheadedness is sometimes noticed but usually quickly passes after several minutes.
Q.) How often are these injections given? At what cost?
A.) The initial pilot study performed small injections at the motor points every two weeks. As the torticollis was brought under control, the injections were spread out in time, to every 4-8 weeks. The cost of the phenol preparation by our pharmacy is about $50. Compared with the cost of botulinum toxin, there is a significant savings.
Q.) Do you anticipate any long-term side effects? Do you do any follow-up of your patients? How long have you been giving these?
A.) There are no significant long-term side effects that I can gather from the literature on phenol. Phenol is very closely related in its chemical structure to other compounds that have been linked to cancer. However, given the dosages that we are working with there is very little to be concerned about. Nonetheless, we try to discuss the risks with every patient who chooses this form of therapy. Most of the original patients are closely followed, because eventually they may need further injections. The original pilot study began over a year ago.
Q. ) Have there been any long-term side effects done for other conditions Phenol has been used for?
A.) There have been no significant long-term side effects that have been appreciated for the other conditions for which phenol has been used. On the other hand, it may not be sufficient in controlling the dystonia or spasticity either. In patients where their respective movement disorder was stronger than our ability to peripherally denervate the nerve or muscle, those patients are referred for surgical intervention.
Q.) What has been your success rate?
A.) The success rate should be viewed in terms of which patients were injected. The patients who were selected had all failed treatment with botulinum toxin. In my laboratory, botulinum toxin helps or controls dystonia in about 90 % of patients with spasmodic torticollis. The remainder still would like to have an alternative treatment. In the pilot study, 85 % of patients reported improvement in their torticollis. Some improvements were dramatic and others were less so. However, I believe that it is a useful adjunct in the treatment of ST.
Q.) What, if any, complications have you seen?
A.) The only problems that we have encountered have been the localized pain with the injection, an occasion radiating an unusual sensation if a sensory nerve has been affected, and muscle spasms. Most patients report that they can handle the injections well.
Q.) Can Phenol be applied after Botox ® has been applied? If so, should there be a certain time lapse between the last Botox ® injection and the first Phenol injection? Or vice-versa?
A.) There is no theoretical reason why Botox Ò and phenol cannot be used together. The only reason to wait a sufficient time between the two injections is to provide the physician with information as to which therapy is providing any therapeutic improvement. It is my personal feeling that phenol is an alternative to treatment with botulinum toxin, and will not take its place as a primary form of treatment for ST.
Q.) Can Phenol be used after selective denervation or rhizotomy surgery has been carried out" If so, then is there an optimal time that should elapse before the Phenol is applied?
A.) Phenol can be used after selective denervation. The only recommendation that I would make is to wait long enough post-operatively to decide how successful the surgery had been. However, if post-operative pain or muscle spasms are a problem then injections sooner rather than later may be advised.
Q.) If Phenol is used, will this lower the probability that Botox ® will become effective after the Phenol has been applied? Or does the injection of Phenol limit the probability that selective denervation could be carried out on the patient? We have heard that Phenol will produce scarring and/or tissue build-up so that an operation may be difficult and/or impossible to perform?
A.) I do not feel that we have enough information available to know how Botox Ò might work after a series of phenol injections. As to the scarring that may occur after the use of phenol, again I do not believe that we have a good deal of information regarding this. In a single patient that I sent for surgery after injections with phenol, the surgeon had no complaints about scarring where the injections were performed.
Q.) Is this for everyone of just for a certain type of ST?
A.) I feel that most types of ST (torsion, retrocollis, and laterocollis) will probably respond to this form of therapy. It may be more a matter of assessing the degree of success or improvement with other forms of treatment prior to considering phenol.
Q.) You have had much experience with providing Botox ® injections. Can you compare the two? Is one better than the other? Will Phenol replace Botox ® ? Or is Phenol just for certain types of ST and/or people?
A.) Botulinum toxin A is easier to work with and only requires injection in the muscle involved with the dystonia. Phenol is more difficult to work with because it requires more time in locating the best site for injection. Phenol has been described as being slightly more painful than the Botox Ò injection. It is doubtful that phenol will ever replace Botox Ò as the primary therapy. However, it does provide an alternative other than the surgical selective denervation procedure. The first line of treatment for most ST patients will remain botulinum toxin.
Q.) At this stage of the game, should people "Beware"? Should they go to just any doctor? What is your advice to an ST'r at this time?
A.) My advice to most patients is to be careful in going to someone who can "cure" ST. Most physicians will feel comfortable attempting drug treatments or even botulinum toxin injections. These will probably work for a vast number of ST patients. However, if treatment appears to have stopped working, it may not be you or your doctor's fault. Cervical dystonia is a dynamic condition, both in how it affects the patient as well as how various treatments interact with the ST. The greatest service that you can do for yourself it to be re-evaluated by a physician or medical group well versed in ST and its various treatment options. I am sure the ST/Dystonia would be more than helpful in identifying the medical center closest in terms of evaluating your treatment options.
Thank you, Dr. Auberle, thank you very much. Your answers, I'm sure have enlightened all of us with ST - an important service.
(Ed. Note: In further conversation with Dr. Auberle, he stresses he injects 90% of his patients with Botox ® . Phenol is merely an alternative. It's not a whimsical choice just because Botox ® is not as successful as what people think it should be.)
