In the realm of surgical innovation, the quest to minimize complications and improve
patient outcomes is an ongoing and challenging journey. The evolution from conventional
thoracotomy (CT) to minimally invasive techniques, including robotic surgery (RS),
has propelled the field of cardiothoracic surgery forward, but novel approaches beyond
surgical techniques hold the potential to further revolutionize clinical practice.
Notably, systemic inflammation, measured with C-reactive protein (CRP) and interleukin
(IL)-6, has been shown to be crucial in the pathogenesis of postoperative complications
(1).
Vagus nerve stimulation (VNS), an innovative therapeutic technique involving electrical
stimulation of the vagus nerve, has captured the medical community’s attention due
to its ability to modulate various human body functions. The vagus nerve, a critical
component of the parasympathetic nervous system, plays a pivotal role in regulating
cardiac, pulmonary, and gastrointestinal functions, and even inflammation (2). By
harnessing the power of VNS, we unlock a promising avenue for addressing a spectrum
of conditions, including—but limited to—epilepsy, depression, and inflammatory disorders.
As the landscape of VNS research continues to unfold, it holds the potential to revolutionize
the way we approach and manage a variety of medical conditions.
The recent study by Carvalho et al. (3) sheds light on VNS in the context of postoperative
inflammatory responses following thoracic surgery. This preclinical study explores
the use of VNS to reduce the systemic inflammatory response syndrome (SIRS) and clinical
complications associated with CT and RS in a pig model which is comparable to human
physiology, histology, and immune response (4).
Their results indicate that VNS led to a more stable heart rate during the postoperative
period and reduced cardiac complications, making it a potential non-pharmacological
tool for mitigating the inflammatory response and complications, particularly in aggressive
surgical procedures. While applauding the authors’ dedication to advancing surgical
outcomes, several key points deserve further discussion and clarification.
The application of VNS in the reduction of proinflammatory cytokines like IL-6 levels
after thoracic surgery is attractive. However, human studies have already established
the potential of autonomic neuromodulation, including VNS, in reducing IL-6 levels
post-cardiac surgery (5). Therefore, it is of utmost clinical significance to explore
the effect of VNS on clinical outcomes beyond surrogate inflammatory biomarkers and
physiological responses. Clinical endpoints, such as the incidence of postoperative
atrial fibrillation, infection rates, recovery duration, and mortality rates are essential
for assessing the translational potential of this approach in clinical practice.
Furthermore, the invasive nature of mediastinal VNS, involving electrode implantation,
raises concerns about its impact on surgery duration and potential complications,
such as vascular and neurological injuries (6). These considerations may outweigh
the perceived benefits of VNS in the postoperative period. Exploring less invasive
alternatives, like transcutaneous auricular VNS, which has yet to prove equivalent
to cervical or mediastinal VNS, might hold promise. Moreover, the authors found that
the pigs that have undergone CT benefited the most from the VNS. As CT has been to
a significant extent replaced by minimally invasive approaches, the applicability
of mediastinal VNS in routine thoracic surgery becomes less feasible and practical,
warranting the exploration of alternative methods, including but not limited to noninvasive
VNS.
Last, although this study’s findings demonstrated a reduction in the postoperative
inflammatory response, it’s worth noting that the study did not delve into the underlying
mechanisms responsible for this anti-inflammatory effect. Overall, prior work has
described the action of VNS via the anti-inflammatory pathway at the spleen, further
mechanistic studies within the specific context of postoperative thoracic surgery
are essential. Specific aspects of postoperative complications such as postoperative
atrial fibrillation have been recently elucidated, and these could serve as the basis
for future work on this condition (6).
In conclusion, the investigation into VNS as a means to mitigate postoperative inflammatory
responses in thoracic surgery is a commendable endeavor. However, a comprehensive
approach that incorporates existing knowledge, delves into mechanistic insights, prioritizes
clinical outcomes, and elucidates the feasibility of VNS in practical surgical settings
will enhance the impact and relevance of this research. Addressing these key points
will undoubtedly bolster the advancement of surgical techniques and, most importantly,
enhance the well-being of patients undergoing thoracic surgery.
Supplementary
The article’s supplementary files as
10.21037/atm-23-1889