Devotees of oriental medicine will not be surprised by the finding, in the British Journal of Anaesthesia, that acupuncture reduces pain after surgery. More unexpected is that chili powder applied to the skin below the knee can produce the same effect!
In this meta-analysis fifteen studies were analysed – over 1100 patients. In each study, acupuncture was compared with control “sham” acupuncture (acupuncture applied to non-acupuncture points).
- Acupuncture patients needed less opioid (morphine-like) pain treatment at 8, 24 and 72 hours after surgery
- Postoperative pain was also significantly less in the acupuncture group at 8 and 72 h compared with the control group.
- The acupuncture treatment group had a lower incidence of opioid-related side-effects such as nausea, dizziness, sedation, pruritus (itching), and urinary retention (inability to urinate).
The authors conclude that “perioperative acupuncture may be a useful adjunct for acute postoperative pain management”. I was intrigued, and decided to explore the methods used in one of the 15 studies in a bit more detail (Kim KS, Nam YM. The analgesic effects of capsicum plaster at the Zusanli point after abdominal hysterectomy. Anesth Analg 2006; 103: 709–13).
In this study, needles were not used. This should make the technique a bit more acceptable to needle-averse patients i.e. most Westerners and all children. (The study however included no children and, as it was performed in Korea, probably no Westerners).
Capsaicin is the compound in chili peppers that makes them taste hot. Capsicum plaster (PAS) is a capsaicin mixture of powdered capsicum and capsicum tincture on a sheet. After application the sheet is covered with an adhesive plaster. This method apparently is widely used in Korea.
The Zusanli acupuncture point (Chinese: 足三里, ST36) is four finger breadths below the lower margin of the patella and one finger breadth lateral from the anterior crest of the tibia. The Zusanli acupoint lies on the stomach meridian and is used in the treatment of lower abdominal pain. In the study, the treatments (capsaicin, control or sham) were applied 30 minutes before anesthesia and were maintained for 8 hours per day for 3 days.
PAS is “noninvasive, simple, painless, and easy to apply”. The size (5 × 5 mm2) of the patch is convenient, and capsicum gets from the patch and into the skin surface within 8–12 hours. PAS is also inexpensive ($1 per 5 sheets), especially when compared to anti-nausea drugs or to transcutaneous electrical acupuncture devices like the ReliefBand.
The Zusanli acupoint was first confirmed by the acupuncturist using an acupuncture needle. It’s not clear from the study description whether this is a prerequisite for correct application or whether you can simply apply the patch to the appropriate area below the knee. (De-Qi is a sensation typically associated with proper acupuncture needle positioning and many practitioners say this sensation is crucial in achieving the effect of acupuncture. However, when PAS is applied on an acupoint, De-Qi is unlikely to be elicited).
The results of this pchili powder study were in keeping with the results of the meta-analysis i.e. pain levels were reduced and less analgesic medication was needed.
So, with the above caveat about plaster application in mind, I conclude that PAS may be a useful addition to standard pain treatment in patients having abdominal surgery. It may be especially helpful for those in whom usual analgesic medications have been less successful, or have lead to side-effects, and for individuals who simply prefer non-drug treatments. I can’t wait to offer it to my next hysterectomy patient, if I can just get my hands on some PAS plasters!