Long-segment spinal fusions are effective interventions to relieve pain, neurological
compromise, or disability related to a variety of causes of advanced spinal degeneration
or spinal deformity. Despite advancements in minimally invasive spine surgery, revision
of prior instrumentation, correction of coronal or sagittal imbalance, bony
decompression, and multilevel arthrodesis often must be performed via open surgery. While
these procedures can produce excellent results with regards to postoperative alignment,
neural decompression, and functional improvement, they are long and invasive cases
requiring large incisions and extensive soft tissue dissection and osseous manipulation.
As such, postoperative adverse events or complications are common (e.g., DVT/PE, wound
healing problems, infection, nerve stretch injury, etc.). These patients almost
universally experience significant postoperative pain, require postoperative
rehabilitation, and are at high-risk for hospital readmissions. Moreover, the sterile
trauma from long-segment spinal surgeries is a tremendous systemic inflammatory stimulus
that yields downstream sequelae such as hyperglycemia, elevated inflammatory markers
(e.g. cytokines), signs of microvascular ischemia, and other stress-related outcomes.
Attempts to control this inflammation and reduce the adverse effects of these surgeries
are lacking, particularly with respect to non-pharmacologic options.
Vagal nerve stimulation (VNS) is a promising emerging modality by which the body's
systemic inflammatory response may be attenuated. Importantly, VNS may be successfully
applied via noninvasive auricular stimulation. This technique has been trialed as
non-pharmacologic pain control adjunct after multiple types of surgeries or painful
medical events, but none as traumatic as long-segment spinal fusion. It also has been
shown to yield substantial anti-inflammatory effects in numerous animal models.
Furthermore, auricular VNS has been extensively studied at Washington University School
of Medicine in multiple neurological conditions, including aneurysmal subarachnoid
hemorrhage, acute ischemic stroke, and intraparenchymal hemorrhage. The use of
noninvasive VNS devices has been shown to be an intervention that is safely administered
and does not cause undue distress to patients. Given these promising aspects of VNS,
Washington University's particular interest in this treatment modality, and the unmet
postoperative care needs for long-segment spinal fusion patients, the investigators
propose prospectively studying the effects of auricular VNS in a population of patients
at Barnes-Jewish Hospital who have undergone long-segment fusion surgeries. The
investigators hypothesize that perioperative VNS will mitigate the systemic inflammatory
reaction in these patients as demonstrated by reduced inflammatory markers (both direct
and indirect) and improved inflammatory-mediated clinical outcomes.
This study will be a randomized controlled trial assessing differences between accepted
perioperative care plus auricular VNS (the intervention) as compared to accepted
perioperative care plus a sham stimulus. The VNS device will be a noninvasive stimulator
applied to the left ear to stimulate the auricular branch of the vagus nerve. All
patients will be fitted with the device, and the sham stimulus will not receive the
required therapeutic stimulation through the device. Patients will receive stimulation
twice on the day of surgery followed by twice daily during the duration of their
postoperative hospital admission. Relevant inflammatory cytokines, laboratory tests, pain
scores, clinical outcomes, and imaging studies will be obtained for each patient.
Post-hospital disposition, delayed adverse outcomes, and hospital readmissions will also
be tracked after discharge.
