Stimulated by Yang et al 2024.[1]
EA – electroacupuncture
key to acronyms
CUR – chronic urinary retention
QoL – quality of life
SNS – sacral nerve stimulation
POUR – post-operative urinary retention
PVR – post-voiding residual (urine volume)
EA – electroacupuncture
POCUS – point of care ultrasound
This is a relatively small retrospective cohort study (n=20) from Beijing, but the last author on the paper (the boss) has a very good track record in acupuncture research, and the clinical condition is difficult to treat and has a considerable impact on QoL. Interestingly, I sat in on a consultation in the GI physiology department for the first-time last week and met a patient who had an SNS implant. These devices cost thousands of pounds and need to be replaced intermittently at similar eye-watering prices. I mention this because SNS is used for a variety of chronic urinary conditions including chronic retention, as well as for faecal incontinence.
The patients in this cohort had undergone pelvis or lumbosacral tumour resections resulting in some degree of compromise to nerves affecting bladder function either in the pelvic plexus or cauda equina. Such patients with post-operative urinary retention often regain a relatively normal voiding pattern within 3 months of surgery and use intermittent self-catheterisation while awaiting a return of more normal voiding. Some patients, however, need to continue self-catheterisation indefinitely.
At this stage, because we are going to consider the results of a cohort study (ie there is no control for natural history), it would be really useful to have a percentage figure for possible natural resolution of CUR following surgical nerve damage. Despite searching PubMed and more widely on the Internet, I could not find the figure I wanted. I did find a review on POUR following urogynaecological surgery from 2014, which is close, I guess.[2] This paper gave figures of 2.5% to 43% for the incidence of POUR, and then said that most cases resolved after 4 to 6 weeks. The incidence of CUR, ie POUR going on beyond 3 months, is very low, but presumably slightly higher when the surgery is more extensive, as in this cohort.
The patients included in this cohort study had CUR defined by PVR >300mL and were >3 months post-surgery for pelvic or lumbosacral tumour resection.
The patients were treated with EA 3 times a week for between 2 and 12 weeks. So, that is between 6 and 36 sessions. The following points were needled bilaterally at each session: BL23, BL32, BL33, BL35, SP6. At BL23 and SP6, 40mm needles were used. At the sacral and coccygeal points 75 to 100mm needles were used. At BL32 and BL33, needles were inserted 70 to 95mm angled inward and downward 60 to 75 degrees. I am assuming the angulation is to the surface of the body.[3] These 2 points target the S2 and S3 foramina. BL35 points lie either side of the coccyx and the needles at these points were inserted 60 to 70mm in a superolateral direction.
The stimulation parameters varied with the local and distant points. BL32, BL33, and BL35 were stimulated at a frequency of 5Hz and an intensity of 5–10mA. SP6 was stimulated at a frequency of 10Hz and an intensity of 1–2mA. I guess that EA was not applied to BL23.
Responders were defined by a reduction of 50% or more in baseline PVR. Satisfactory spontaneous urination was defined as a PVR <100mL. 70% of patients (n=14) had responded to EA treatment and stopped self-catheterisation within 12 weeks. 35% of patients (n=7) had complete resolution with PVR reduction from baseline of 90 to 100%.
This is a very encouraging result but there are 2 significant hurdles for us in the West. First, we do not have the established capacity for providing or even trying to provide treatment 3 times a week, and secondly, it is really hard to get needles blindly into sacral foramina. The latter would involve multiple attempts with periosteal contact, which for most patients would be rather uncomfortable.
A colleague (Amit) has used POCUS to facilitate access to sacral foramina, but that comes with a price tag of several k as well, although not necessarily as much as an SNS implant.
References
1 Yang M, Zhu L, Yao H, et al. Effects of electroacupuncture on chronic urinary retention after pelvic or lumbosacral tumor resection surgeries: a retrospective cohort study. Transl Androl Urol. 2024;13:397–405.
2 Geller EJ. Prevention and management of postoperative urinary retention after urogynecologic surgery. Int J Womens Health. 2014;6:829–38.
3 Katayama Y, Kamibeppu T, Nishii R, et al. CT evaluation of acupuncture needles inserted into sacral foramina. Acupunct Med. 2016;34:20–6.
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