Imagine this: your 12-year-old child broke his foot and
needs surgery to fix it. You are against the typical pain medications like
Morphine and Fentanyl because of their systemic effects, so what can you do?
Thankfully there is a developing method of pain management that is relatively
easy and very effective: continuous peripheral nerve blocks. Nerve blocks have
been used for a long time for such operations as minor dental work but in the
recent years (2000 and on) continuous nerve blocks have been used for war
injuries/amputations and post surgery pain management. When an injury or
surgery takes place, pain receptors called nociceptors depolarize in response
to the stimuli and send action potentials up their associated nerve, through
the body and to the appropriate brain areas and pain is felt (Vas 2005). Continuous
peripheral nerve blocks are a relatively simple idea where the sensory nerve
sending signals from the injury site to the brain is isolated using imaging
techniques and continuously infused with local anesthetics. These local
anesthetics such as Bupivacaine or other –caine drugs, are continuously pumped near or sometimes into the nerve and work to block the action
potential coming from the injury site. Bupivacaine does so by binding the
intracellular portion of sodium channels, blocking sodium influx and therefore
propagation of the action potential. This is hugely beneficial to the world of
pain management because drugs like Morphine work to dumb the pain down once the
brain receives the signal but nerve blocks stop the signal from ever reaching
the brain. Imagine a road between your house and McDonalds. You want McDonalds
but its bad for you, just like you want pain signals but they hurt and are not
comfortable. A continuous peripheral nerve block is like a drawbridge that is
raised on that road, not allowing you to get McDonalds. Once McDonalds is
closed for good (i.e. your pain is gone) the nerve block is lifted and the
drawbridge is put back down and you can drive like normal to Whole Foods. A study done on
battlefield injuries found that continuous nerve blocks contributed to better
pain outcomes, even while the patient was transported in a huge plane for 13
hours (Buckenmaier et. al 2009). This
procedure has been vastly improved thanks to the War on Terror and the sacrifices
made by the soldiers and we now have many practical uses in the US. Nerve blocks
are now used for helping patients with hip fractures by blocking the femoral
nerve (Layzell 2013). This is hugely important because hip fractures are
usually in elderly patients who are extremely sensitive to narcotic pain medicines
like Morphine. We will be seeing a lot more of this procedure in the near
future, the localized effects are much greater than systemic effects caused by Morphine.
Buckenmaier CC, Rupprecht C, McKnight G, McMillan B, White
R, Gallagher RM and Polomano R. Nov 2009. Pain following battlefield injury and
evacuation: a survey of 110 casualties from the wars in Iraq and Afghanistan.
Pain Medicine. 10(8):1487-1496
Layzell MJ. Aug 2013. Use of femoral nerve blocks in adults
with hip fractures. Nursing Standard. 27(52):49-56.
Vas L. 2005. Continuous sciatic block for leg and foot
surgery in 160 children. Pediatric Anesthesia. 15:971-978
http://www.drugs.com/pro/bupivacaine.html
Quality post Ian, but I was wondering on how exactly the blocks were administered over a longer period of time? With an I.V. near the site of injury or a direct delivery with a needle near the nerve? I'm wondering if the administration of these drugs would result in the same problems diabetics experience with repetitive use of the same insulin injection site?
ReplyDeleteType 1 diabetics can develop lipohypertrohy (fatty masses that accumulate with repeated use of the same injection site) (American Diabetes Association). Lipohypertrophy decreases insulin absorption in diabetics, and I could see this causing a similar problem with repeated nerve blocks. Particularly with hip fractures, which can take several months to heal. Just a thought.
References:
1. http://care.diabetesjournals.org/content/26/suppl_1/s121.full
Good thought Joel. They are administered by a needle similar to a diabetic infusion pump but this is placed more carefully. I can not imagine it having the same side effects as insulin administration because this is not a chronic issue and only over a relative short time (hopefully!).
ReplyDeleteGreat post Ian, very informative. Last year I had knee surgery and opted for a nerve block. I remember the physician placing a long needle in my groin multiple times to find the right nerve. They would hit a nerve and see which area of my leg responded to that nerve, and then proceeded to reinsert the needle to find a different nerve. I finally succumbed to the anesthesia, so I do not remember how many times they did this. When I woke up from surgery I could not feel my left leg from my hip down. It was a surreal feeling. When I went to walk down the hallway, I naturally went to put slight pressure on my leg, but forgot I couldn't feel it and I ended up falling into a wall. Over the next few days, the area of needle insertion was very sore and bruised. This being my second knee surgery, but the first time with a nerve block, I do not think I will opt for a nerve block again. I just thought I would share this, because nerve blocks are a great way to manage pain, but they also have some minor side effects people do not think about. I think implementing nerve blocks instead of morphine is a great way to mange pain, and would also weed out those people who seek out morphine for pleasure rather than a real injury, because nerve blocks are not exactly pain free.
ReplyDeleteI was interested in this post and alternative ways to block pain and reduce side effects of major drugs for surgery. I would like to offer another alternative that has gained some interest in recent years in the US - Acupuncture. There is a lot of research on the use of acupuncture for blocking pain during surgery. Some research are using acupuncture with low doses of anesthetics for open heart surgery, and they found that the patients had less infections, shorter stays in the hospital, and lower costs of treatment overall (1). Also, Acupuncture has been used successfully in dental surgery for those allergic to Lidocaine (2). It is really interesting to me that the Aetna health insurance that Regis offers also covers medical acupuncture for these cases, it must be cost effective as well as functional. I've used acupuncture many times in the past for pain, especially after a car accident where I was experimenting with not taking pain killers and Acupuncture did help tremendously.
ReplyDeleteReferences:
1. Hu, Wen-Long, Chih-Hao Chang, Yu-Chiang Hung, and Tien-Yu Shieh. Acupuncture Anesthesia for Complicated Dental Extractions in Patients with Lidocaine Allergy. The Journal of Alternative and Complementary Medicine 15, no. 11 (2009): 1149-1152.
2. Zhou, Jia, Hao Chi, Tsung O. Cheng, Tong-yu Chen, Yao-yao Wu, Wen-xiong Zhou, Wei-dong Shen, and Lan Yuan. Acupuncture anesthesia for open heart surgery in contemporary China. International journal of cardiology 150, no. 1 (2011): 12-16.