In another study exploring nonsystemic treatment modalities, Jabbari B. found that patients with chronic low back pain may respond to injections of botulinum toxin A. In a prospective study involving 75 patients, patients received paraspinal intramuscular injections at baseline and then at recurrence of pain, typically at 4, 8, and 12 months after the initial therapy. Although a modest number of patients reported significant improvement, 56% at 3 weeks and 54% at 2 months, the investigators did note that among initial responders, 90% responded to subsequent treatments. Among the patients overall, there were 3 adverse events — 2 transient flulike reactions and 1 episode of acute root pain after the injection.
Botulinum toxin injection is used to treat dystonia, a neuromuscular disorder that produces involuntary muscle contractions, or spasm, that affects muscles that control movement in the eyes, neck, face, voice box, or the smooth muscle in the bladder. The goal of the therapy is to reduce muscle spasm and pain.
This potent neurotoxin is produced by Clostridium botulinum, a bacterium that causes food poisoning (botulism). There are seven known types of C. botulinum toxin, but only types A (Botox) and B (Myobloc) are used as medical treatments.
Botulinum toxin has proven to be useful in the treatment of many forms of dystonia, including the following:
blepharospasm, forceful involuntary closure of the eyelids
strabismus, misalignment of the eyes hemifacial spasm, sudden contraction of the muscles on one side of the face spasmodic torticollis, or cervical dystonia, muscle spasm in the neck that causes the head to turn to one side, and sometimes forward or backward oromandibular dystonia, continuous spasms of the face, jaw, neck, tongue, larynx, and in severe cases, the respiratory system urinary retention, severe inability to urinate that requires catheterization spasmodic dysphonia, spasm of the vocal cords that causes sudden disruption of speech stuttering, repetitions of parts of words and whole words, long pauses, elongated sounds voice tremor, quavering vocalization.
Neurons generate new nerve endings that reactivate the dystonia, so improvement is not long lasting, and treatment is usually repeated every 3 to 4 months. Physical or occupational therapy usually is undertaken to stretch and restore normal muscle function. Some patients develop antibodies to the toxin over time, rendering the treatment ineffective.
This is a safe and effective treatment when given in very small amounts by a qualified neurologist. Some patients experience temporary weakness in the group of muscles being treated. For example, ptosis (drooping eyelid) can develop after treating blepharospasm. Flu-like symptoms develop in some, but rarely.
What is a selective nerve root block?
A selective nerve root block is a procedure that is used diagnostically to identify whether a spinal nerve is the generator of pain. Additionally, coincident injections of corticosteroid along with the local anesthetic block can be therapeutic and relieve pain.
What can I expect at the Pain Center?
A Pain Management Specialist at the clinic will assess your pain condition, take a medical history, and examine you to see if the procedure is a potentially beneficial option. At this time any precautions that need to be taken based on the status of your health may be discussed. Additional or alternative treatment options can be discussed. After this examination, the procedure can then be scheduled.
What should I do before the procedure?
Do not eat or drink non-clear liquids 6-8 hours prior to your procedure. You may drink a small amount (a few ounces) of clear liquid (water) up to 2-3 hours before your procedure. Take your routine medications the day of your procedure as you normally would with a small amount of water, unless instructed otherwise by the physician. If you take pain medications, do not take a dose 2 hours prior to your procedure time, unless otherwise instructed by the physician. If you take blood thinners (such as Coumadin), or you are a diabetic, you will need to follow special directions which the physician will give you prior to the procedure. It is mandatory that you arrange for someone to drive you home from the ambulatory surgical center after your procedure. Additional instructions may be given by the physician if necessary depending on your health status.
Where will the procedure be done?
In the ambulatory surgical center as an outpatient.
Will I be asleep for the procedure?
Monitored anesthesia care with light sedation may be medically indicated, based upon your health status, or to reduce unintentional movement during the procedure. Your physician will discuss this with you at the time of your appointment.
When will I have some relief of pain?
You may receive immediate pain relief after the procedure. If a patient receives partial improvement, then repeat injections may be indicated.
Will I be able to drive afterward?
No, do not operate motorized vehicles/equipment (ie cars, lawn mowers, power tools, kitchen appliances, etc) until the day after your procedure, especially if you have received sedation.
Will I be able to resume my normal activities after the procedure?
Yes, the next day. Just maintain good body mechanics and posture and continue with physical therapy or your home exercise program.
What are the risks of the procedure?
A full discussion of the risks of the procedure will occur when you meet the Pain Specialist who will perform the injection. Overall, the risks are relatively low.
The use of nerve blocks has also been criticised because of the lack of appropriate double-blind, randomised controlled trials. However, it must be appreciated that these are hard to carry out for non drug treatments, and in such a disparate group of patients as for instance those with low back pain and neurogenic pain. However, it is clear that trials are now being carried out and can show the efficacy of various treatments. On the whole I veer away from permanent lesions for patients with chronic non-malignant pain.
Facet joint denervations have been shown by Lord, Barnsley and Bogduk to be effective for both low back pain and neck pain resulting from whiplash injuries.
Efficacy and safety of epidural steroids have been investigated extensively and recent randomised controlled trials appear to show benefit for their use in limb pain and also in acute back pain or neck pain. It is essential for an appropriate dose to be used and for careful placement of the drug in the correct compartment. I would suggest the use of epidurography at least and the new technique of epiduroscopy is interesting, although as yet completely unproven.
It is understandable and tempting to think of a painful disc as the cause of a significant number of certain patients’ symptoms, and the new technique of disc denervation is another therapy under review at present.
Pulsed radiofrequency has been recommended by Dutch authors, but as yet I fail to see the rationale or the scientific evidence which would lead me to embrace this technique. At least it appears to be side-effect free, although it is a potentially expensive treatment, especially if it is only a placebo!
The use of Botulinum Toxin for muscle spasm is also under investigation at the present time. Clearly the agent has a powerful muscle relaxant effect, which is present from two to six months. Also it appears a relatively safe drug. However a great deal of work needs to be done now to identify the appropriate patients for treatment with this fairly extensive compound.