Inspired by Park et al 2021.
SAE – serious adverse eventkey to acronyms
EA – electroacupuncture
SDAVF – spinal dural arteriovenous fistula
AVM – arteriovenous malformation
CNS – central nervous system
MRI – magnetic resonance imaging
This is the first case report of, yet another SAE related to acupuncture. But there is an important difference to this one. In this case the acupuncture treatment was probably not associated with any technical errors in its application. That’s a bit worrying, isn’t it?
Fortunately, the underlying condition – the presence of an SDAVF – is rather rare. An estimate of the incidence is 5 to 10 per million per year in the general population.
Whilst rare, SDAVFs account for 70–80% of all spinal AVMs, they are 5 times more common in men, they are mostly located between T6 and L2, and the mean age at diagnosis is 55–60 years. Diagnosis is often delayed as the onset of symptoms tends to be insidious. The blood pressure in the spinal arteries is higher than in the spinal veins producing a normal pressure gradient. This promotes normal capillary flow and perfusion of the cord. An SDAVF will have little effect on the arterial pressure in the spinal arteries but will increase the venous pressure in the spinal veins resulting in a more precarious pressure gradient and the potential for oedema and ischaemia in the medulla of the cord.
Sudden onset of more severe symptoms including paraplegia in patients with SDAVFs has been described associated with several different circumstances and procedures, presumably because they influence blood flow and tip the precarious balance in the pressure gradient. Epidural injections and anaesthesia are reported, but also the more innocuous circumstance of lying prone for a prolonged period. I guess the potential for increased abdominal pressure from lying prone, particularly in an overweight patient, can be transmitted to the spinal veins.
In this case, the patient was a slightly overweight 49-year-old male who was already diagnosed following MRI for leg pain and claudication that demonstrated cord oedema. His symptoms fluctuated whilst he awaited an embolization procedure, so presumably he sought acupuncture for symptom relief. He developed paraplegia immediately after or possibly even during EA.
Emergency laminectomy at T12 with coagulation of the SDAVF was successful, and lower limb power recovered to 3/5 in the immediate post-operative period. By 1 month he was walking unaided, and by 1 year he was able to run and climb stairs without difficulty.
There was no sign of dural puncture by an acupuncture needle at surgery, so it was concluded that either the physiological effect of EA on blood flow or the prone position for treatment resulted in the acute vascular myelopathy he experienced.
I think this is the first SAE I have come across where the physiological effect of acupuncture may have been partially responsible for the onset. Whilst a prone position might raise venous pressure, a segmental sympatholytic influence post-EA might reduce arterial pressure, and perhaps the combination was responsible for the rapid onset of symptoms in this case.
SDAVMs are a diagnostic challenge and this can be made worse by their apparent ability to cause myelopathy at a distance from their location. Endovascular techniques can be effective, but it seems that surgery is often required and generally more successful.
1 Park K-H, Jeon C-H, Chung N-S, et al. Rapid Progression to Complete Paraplegia After Electroacupuncture in a Patient With Spinal Dural Arteriovenous Fistula: A Case Report. Front Surg 2021;8:645884. doi:10.3389/fsurg.2021.645884
2 Krings T, Geibprasert S. Spinal dural arteriovenous fistulas. AJNR Am J Neuroradiol 2009;30:639–48. doi:10.3174/ajnr.A1485
3 Marcus J, Schwarz J, Singh IP, et al. Spinal dural arteriovenous fistulas: a review. Curr Atheroscler Rep 2013;15:335. doi:10.1007/s11883-013-0335-7
4 Martinez M, Hedjoudje A, Pardo C, et al. Cervical spinal dural fistulas leading to remote thoracolumbar myelopathy: A diagnostic pitfall. Neurol Clin Pract 2020;10:340–3. doi:10.1212/CPJ.0000000000000724
5 Fox S, Hnenny L, Ahmed U, et al. Spinal dural arteriovenous fistula: a case series and review of imaging findings. Spinal Cord Ser Cases 2017;3:17024. doi:10.1038/scsandc.2017.24