This is really the million dollar question for human kind, but in the case of nerves, I believe we have some ideas.
This post will be a relatively short one, but this question is very important. I have been queried about this phenomenon numerous times. Peripheral compression of the occipital nerves can come from muscles in the neck, scar, fascia (a tough type of connective tissue) and blood vessels, specifically branches of the occipital artery. When the latter are involved, the pathology to the nerve is much like that of an anaconda strangling its prey if the blood vessel is wrapped around the nerve or alternatively that of a jackhammer if the artery lies next to the nerve in a small and fixed space. In both cases, when the blood pumps through the artery with greater force, the pulsations will pound the nerve with greater force. Hence, when blood pressure increases, so does the pulsatile force against the nerve and hence the pain.
What types of things can cause blood pressure to rise? Not surprisingly these forces are many of the same triggers that people report all the time: stress, exercise, caffeine ingestion, pain, etc. To illustrate the point, take a look at my recent post with a picture and a video of a greater occipital nerve in the process of being decompressed. During the dissection, I was able to demonstrate a pulsatile occipital artery branch passing right over the greater occipital nerve. In addition, once someone experiences pain, their blood pressure rises which in turn causes the arteries to pump harder thus causing more pain, which causes a further rise in blood pressure and setting in motion a terrible positive feedback loop. For these reasons, when we see vascular compression of the occipital nerves in the OR, we tie off and/or cauterize those vessels so that they no longer impact the nerves.
For more information on how nerve decompression can help solve your occipital neuralgia issues, visit www.peledmigrainesurgery.com and call 415-751-0583 for an appointment.
This post has been a long time coming. It seems that almost daily, I get a question from some patient somewhere wondering why their (insert body part here) hurts when they’ve had a nerve injury despite the fact that the area feels numb to the touch. This phenomenon can be seen in patients suffering from diabetic neuropathy (most commonly noted in the lower extremities), amputees with phantom limb pain and anyone with a sensory nerve injury anywhere else (e.g. the head/neck region). I will qualify my remarks below by saying that this topic is a huge one and cannot be covered in its entirety in a brief post or even a book chapter. There are whole journals published monthly devoted to the study of such clinical dilemmas. The goal here however is to provide a general understanding of why one might have these types of sensations and as a launch point for discussion with your treating physician about what can be done. I will also use phantom limb pain as the template for understanding this problem as it is one of the most common manifestations of this problem and the one most conceptually accessible to a non-physician.
WHY DOES IT HURT SO MUCH AFTER THE INJECTION?!?
I’ve heard from so many people over the years who consistently tell me that they had worse pain AFTER their injections - whether it is Botox, a local anesthetic (such as is used in nerve blocks) and/or steroids. Remarkably, despite numerous queries to their treating clinicians, their physicians have never had a good answer for them as to why this problem happens. Actually, the answers are quite simple. Worse pain after injections such as those done to diagnose ON can occur for several reasons.
One reason is that the injections done for ON are performed within muscle. Injections into muscle cause a little muscle inflammation/swelling no matter what you inject (even saline) and this inflammation causes discomfort. Anyone who has ever had a tetanus shot into the shoulder muscle (deltoid) knows exactly what I’m talking about. Their shoulder can be sore for 7-10 days afterwards. Fortunately, the discomfort is temporary and only lasts a few hours or days as the inflammation/swelling subsides.
Second, keep in mind that the injections, by design, are performed AROUND (not into) nerves which means that you are injecting several mL of fluid around a nerve. This fluid causes some irritation of the nerve itself because of the mechanical pressure from the fluid, not so much the make-up of the fluid itself and hence theoretically would be equivalent with Botox, local anesthetics or steroids so long as the same volume was used with each. If a local anesthetic is used, the effects of the anesthetic provide relatively immediate, albeit temporary relief when injected properly. Yet when the effects of the local anesthetic wear off, the nerve irritation from the fluid pressure often remains and can cause worse pain for a few hours or days afterward. Once again, this situation is usually temporary as the residual fluid is absorbed by the body, although the discomfort can last several days on occasion.
A third reason an injection can cause pain afterwards is some complication from the injection itself. For example, following any violation of the skin (e.g. surgery, injections, IV placement) an infection can occur. With infection comes the inflammation mentioned above several times often causing localized pain from irritation of the nerve endings in the surrounding skin as well as from irritation of the target nerve. A hematoma (a collection of blood) can result from an injection although it is quite uncommon. Blood is a great culture medium and can be a factor in promoting infection (see above) as well as a mechanical force impacting the local tissues (e.g. the target nerve). One potential sign of a hematoma is significant bruising following an injection, especially one involving a small needle and a small injection volume. Finally, and fortunately very rarely, an intra-neural injection (into the nerve itself) can be the culprit. If a significant volume of anything is injected into the nerve itself, it can disrupt the microscopic blood supply to the nerve and cause permanent damage, which can result in permanent problems. However, since nerves are usually quite small, since the injection needles are small and since the required injection volumes are low, intra-neural injections are about as common as finding a needle in a haystack or a four leaf clover. The take home message for my patients: knowledge is power. If patients are told what MAY happen following their injection, they are much calmer if and when it does occur and hence better prepared to deal with the situation.
For more information about how Botox injections can help with your cosmetic or pain issue, please visit www.peledplasticsurgery.com or call 415-751-0583 today to make an appointment.
First of all, what is a neuroma? A neuroma can be defined in one of two ways. One, as a tumor composed of nerve tissue such as an acoustic neuroma. Almost overwhelmingly, these tumors are benign. The more common usage of the term neuroma means a mass of nerve tissue consisting of regenerating nerve fibers that have been previously severed or injured somehow. When a nerve is injured, it tries to re-grow - that’s what nerves do. If that nerve re-grows into the scar at the skin, it can cause exquisite pain even with light touch in the area. This situation would be akin to having a cavity (which hurts because the nerve at the root of the tooth is exposed) and eating ice cream - ouch! So if a nerve is severed or injured in some other way, how do you prevent a neuroma from occurring?
I’ve noted that there has been some confusion lately over the roles of nerve blocks, nerve stimulators and nerve decompression in the treatment of chronic headaches. To be sure, there will be variations in how each clinician may use these modalities, if only because each patient presents a unique clinical dilemma. While I certainly can't speak to the ways in which others utilize these modalities, I can offer general guidelines as to how I use them in my practice. Hopefully this information will also provide some insight into the advantages and disadvantages of each.
To start with the most straightforward, nerve blocks in my hands are used as diagnostic, not treatment tools. If, based upon your history and physical exam it is felt that nerve X may be contributing to your chronic headache symptoms, I would propose to block nerve X. After a few minutes, if your headache symptoms are either gone or significantly improved, it strongly suggests that this nerve is somehow injured and would benefit from surgical treatment. The local anesthetics used in nerve blocks only last a few hours. Therefore, it is fully expected that the headache symptoms will return after the block wears off. However, the results of the block help identify which nerve or nerves may be involved and give an approximation of the numbness that one might have permanently, if those nerves are removed. The numbness should not be permanent if the nerves are simply decompressed and then recover as expected.
As for nerve stimulators, let me first begin by saying that I am no expert on this subject nor do I implant stimulators myself. Having said that, the general idea behind the nerve stimulators is to implant leads around a particular nerve that the physician believes is causing symptoms. The leads are then hooked up to a generator that is often implanted under the skin in a distant location. When activated, this generator produces an electrical current between the leads, hopefully affecting the desired nerve. In doing so, the thought is to put the desired nerve "to sleep" so that symptoms are minimized. Think of this modality as a “pacemaker” for your nerves. As you might imagine, placing a permanent nerve stimulator is a surgical procedure, albeit a relatively minor one. If successful, it is presumed that the patient will have this foreign body within them permanently. Moreover, since no foreign body ever lasts forever (e.g. breast implants, cardiac pacemakers, hip replacements, heart valves) it is likely that another procedure will be required at some point in the future to address issues that come up such as placing new batteries in the generator or fixing leads that may have migrated. My personal view on nerve stimulators is that they should be used as a last resort for all the reasons mentioned above. So I am more apt to consider surgical decompression or neurectomy prior to consideration of an implantable, permanent stimulator.
With respect to nerve decompression or neurectomy, the concept is relatively simple. If there is mechanical pressure on a nerve from, for example, a spastic muscle, tight fascia or a compressive blood vessel, these structures are removed and the pressure on the nerve eliminated. During the operation, the nerves themselves are examined very closely under high-powered loupe magnification. If the nerves themselves are deemed to be too injured and therefore unlikely to recover (resulting in persistent pain) then a decision can be made to excise the nerve and implant the proximal nerve end into the local muscle to prevent future neuroma formation. While no treatment modality is perfect, the published results with nerve decompression and/or neurectomy are quite good, the rates of complications very low and the complications themselves are very well tolerated if they occur. Therefore, putting this information all together, I use diagnostic nerve blocks quite often to decide who is a surgical candidate. A personalized decision is made in each case as to which nerves to treat and whether or not nerve decompression or neurectomy is recommended. I overwhelmingly do the former as I’ve found that nerves often recover even in cases when patients don't think they will and it always leaves me with a fallback option (not taken or stated lightly) of another procedure to excise the nerve(s). When all else fails, a nerve stimulator trial can be performed and if successful, a permanent stimulator could be placed.
Just this month in Plastic and Reconstructive Surgery (the leading plastic surgery journal in the world), Dr. Guyuron published his five-year results with surgical decompression for migraine surgery. The findings of this study show that relief of headaches persists even five years from the time of surgery. More specifically, at five years post-surgery, the average number of migraines per month were reduced to 4 from 11, average migraine intensity decreased from 8.5 out of 10 to 4.5 out of 10 and the average duration of a migraine if and when it occurred was reduced from 1.4 days to 8 hours. Just as impressive were the findings that 88% of patients still reported a significant decrease in their headaches after five years and that 29 reported elimination of their migraines altogether! These results suggest that surgical decompression can produce a lasting if not permanent degree of relief from the debilitating headaches that affect so many people worldwide. If you suffer from migraines and would like to learn if you are a candidate for decompression surgery, please contact our office at (415) 751-0583 or (925) 933-5700.