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J Neurosurg Case Lessons
J Neurosurg Case Lessons
J Neurosurg Case Lessons
Journal of Neurosurgery: Case Lessons
2694-1902
American Association of Neurological Surgeons

10.3171/CASE24263
CASE24263
Letter to the Editor
Letter to the Editor. The need for a documented therapeutic effect before recommending vagus nerve stimulation for recovery after cerebral bleeding
Finsterer Josef MD, PhD 1
1 Neurology & Neurophysiology Censer, Vienna, Austria
Correspondence Josef Finsterer: fipaps@yahoo.de.
INCLUDE WHEN CITING Published September 16, 2024; DOI: 10.3171/CASE24263

Disclosures The author reports no conflict of interest.

16 9 2024
16 9 2024
8 12 CASE24263© 2024 the authors
2024
the authors
https://creativecommons.org/licenses/by-nc-nd/4.0/ CC BY-NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
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pmcTO THE EDITOR: I read with interest the article by Cummins et al.1 about a 67-year-old man with left putaminal intracerebral hemorrhage (ICH) during a hypertensive crisis, clinically manifested by right hemiparesis and aphasia, which improved significantly under vagus nerve stimulation (VNS) paired with 6 weeks of in-house physical therapy 3 years after the event (Cummins DD, Kalagara R, Downes MH, et al. Vagus nerve stimulation for enhanced stroke recovery after intracerebral hemorrhage: illustrative case. J Neurosurg Case Lessons. 2024;7[11]:CASE23676). VNS plus physical therapy resulted in a functional improvement of the right upper limb of 14 points on the Fugl-Meyer Assessment Upper Extremity index for stroke recovery.1 It was concluded that VNS is a promising therapy for improved recovery after hemorrhagic stroke and may provide greater functional improvement than that following VNS after ischemic stroke.1 The study is impressive, but some points require further discussion.

The first point is that I disagree that VNS has not yet been described for the recovery of chronic motor deficits after ICH.1 In a randomized, sham-controlled, open-label, multicenter study on the effect of noninvasive VNS in 61 patients with acute ischemic stroke and 8 patients with ICH with median baseline and 24-hour hematoma volumes of 6.9 (4.5–10.8) mL and 5.7 (4.6–12.6) mL, respectively, none of the 8 ICH patients experienced > 30% hematoma growth or clinical deterioration after VNS at 24 hours post-ICH.2 In an ICH rat model (n = 14), VNS combined with rehabilitation training significantly improved recovery of forelimb function compared to rehabilitation training without VNS.3

The second point is the design of the study. No general conclusions about the effect of a treatment can be drawn from an individual case. In order to assess the therapeutic effect of a medication or other treatment methods, it is imperative to conduct a randomized, double-blind, placebo-controlled, crossover trial in adequately powered active and control cohorts. How could a placebo effect be ruled out in the index patient, and how could a positive effect of physiotherapy alone be ruled out?

The third point is that the treatment was performed 3 years after ICH.1 Treatment responses to VNS can vary significantly between patients with acute ICH and patients with ICH years before the treatment. To assess the effect of VNS in acute ICH, it is imperative to treat ICH patients either immediately after diagnosis or at least shortly after ICH onset.

The fourth point is that a possible therapeutic effect of VNS may depend largely on whether muscle tone is normal, reduced, or increased and whether mobility is limited by tight contractures in the case of spasticity. Therefore, we should know whether the right limb muscles were spastic and joints were contracted.

The fifth point is that it is difficult to draw any conclusions as to whether the effect of VNS was better or worse than that in patients with ischemic stroke. Because no ischemic stroke patients were included in the study, no conclusions about the effect of VNS on ischemic stroke can be drawn.

In summary, the excellent study has limitations that should be addressed before drawing final conclusions. Clarifying the weaknesses would strengthen the conclusions and improve the study. To assess the therapeutic effect of VNS in patients with ICH, appropriately designed studies are mandatory.

Disclosures

The author reports no conflict of interest.

Correspondence

Josef Finsterer: fipaps@yahoo.de.
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References

1. Cummins DD Kalagara R Downes MH , et al. Vagus nerve stimulation for enhanced stroke recovery after intracerebral hemorrhage: illustrative case. J Neurosurg Case Lessons. 2024;7 (11 ):CASE23676.38467050
2. Arsava EM Topcuoglu MA Ay I , et al. Assessment of safety and feasibility of non-invasive vagus nerve stimulation for treatment of acute stroke. Brain Stimul. 2022;15 (6 ):1467-1474.36356829
3. Hays SA Khodaparast N Hulsey DR , et al. Vagus nerve stimulation during rehabilitative training improves functional recovery after intracerebral hemorrhage. Stroke. 2014;45 (10 ):3097-3100.25147331
