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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/CASE24305
CASE24305
Letter to the Editor
Letter to the Editor Response
Cummins Daniel D MD
Joo Park Hyun MD
Tosto-Mancuso Jenna DPT
Putrino David PT, PhD
Panov Fedor E MD
Kellner Christopher P MD
Kalagara Roshini BA
Downes Margaret H BA
1 Mount Sinai Health System, New York, NY
2 Icahn School of Medicine at Mount Sinai, New York, NY
INCLUDE WHEN CITING Published September 16, 2024; DOI: 10.3171/CASE24305.

Disclosures The authors report no conflict of interest.

16 9 2024
16 9 2024
8 12 CASE24305© 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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pmcWe thank Dr. Finsterer for providing a thoughtful perspective on our report using vagus nerve stimulation (VNS) paired with rehabilitation for functional motor recovery after intracerebral hemorrhage (ICH). As for the first point, VNS has not yet been described for the recovery of chronic motor deficits after acute ICH, and we do believe this is accurate. The study by Arsava et al. describes noninvasive VNS in the context of acute ICH (24 hours post-ICH) and therefore does not address the effect of VNS in the setting of chronic motor deficits.1 The differential effects of noninvasive versus invasive VNS are an interesting topic for exploration, which are also important differences between the work by Arsava et al. and our case. The second study described by Hays et al. uses a rat model to test the effect of VNS 9 days after ICH, with impressive improvements in upper-limb function seen in this model using VNS plus rehabilitation.2 However, beyond the differences between rat models and clinical human results, it is unclear how a 9-day waiting period in the rat model translates to chronic deficits > 1 year after ICH in humans. To the best of our knowledge, the use of VNS in the context of ICH in humans with chronic motor deficits (> 1 year from hemorrhage) had not been reported at the time of our description.

As for study design, our report was not meant to study the safety or efficacy of VNS plus rehabilitation for motor recovery after ICH but rather to report initial promising results in one case example. We recognize that a treatment effect cannot be determined from an individual case, and safety and efficacy should be determined by randomized, placebo-controlled trials. In one case, we cannot determine the relative effects of rehabilitation alone or the added impact of VNS. However, in the context of results from Dawson et al.,3 there is reason to believe that some of the effect was from VNS. These results must be validated in larger trials designed and powered to detect such an effect of VNS. We agree with Dr. Finsterer that it may also be interesting to assess the impact of the timing of VNS after ICH, including perhaps in a more acute setting, but this was not the intent of our case report.

As we describe a single case report, we do not directly compare the effect of VNS for ischemic versus hemorrhagic stroke. Rather, using our case in reference to data from ischemic stroke and work from preclinical models, we believe that VNS may be a promising treatment for ICH, and there is reason to pursue larger trials to explore VNS for motor recovery after ICH. We agree that baseline factors such as spasticity can impact the outcomes of VNS plus rehabilitation. The patient in our reported case did have moderate spasticity at baseline, and the range of motion was noted to improve following VNS plus rehabilitation. We thank Dr. Finsterer and look forward to larger trials exploring VNS plus rehabilitation for motor recovery after ICH.

Disclosures

The authors report no conflict of interest.
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References

1. 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
2. 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
3. Dawson J Liu CY Francisco GE , et al. Vagus nerve stimulation paired with rehabilitation for upper limb motor function after ischaemic stroke (VNS-REHAB): a randomised, blinded, pivotal, device trial. Lancet. 2021;397 (10284 ):1545-1553.33894832
