Lidocaine Infiltration and Neuroimmunomodulation in Head and Neck Cancer Surgery

This study aims to investigate whether different doses of locally infiltrated lidocaine affect inflammation, neurological biomarkers, and cognitive function in patients undergoing major head and neck cancer surgery. Major head and neck cancer surgery can cause substantial physical stress, inflammation, and changes in cognitive function after surgery. Lidocaine is a commonly used local anesthetic that may also have anti-inflammatory and protective effects on the nervous system. However, little is known about whether the dose of lidocaine injected into the surgical area influences these responses. This prospective, randomized pilot study will include 20 adult patients undergoing head and neck cancer resection followed by microvascular free-flap reconstruction at University Medical Centre Ljubljana, Slovenia. Participants will be randomly assigned to receive either 150 mg or 300 mg of lidocaine infiltrated into the surgical area at the beginning of surgery. Both groups will receive the same total volume of infiltration solution and the same dose of adrenaline. Blood samples will be collected before surgery, six hours after surgical incision, and on postoperative days 1, 2, and 6 to measure inflammatory and neurological biomarkers. Cognitive function will be assessed before surgery, on postoperative day 6, and three months after surgery. The study will explore whether the higher dose of lidocaine is associated with differences in inflammatory responses, neurological biomarkers, and postoperative cognitive function. The findings will help inform the design of larger future clinical studies.

Inclusion Criteria: * Adult patients aged 18 years or older. * Patients scheduled for oncological resection of head and neck cancer followed by microvascular soft-tissue free-flap reconstruction. * Body mass index (BMI) \< 30 kg/m². * No known hypersensitivity to amide-type local anesthetics or components of the infiltration solutions. * Ability and willingness to provide written informed consent for participation in the study. Exclusion Criteria: * Refusal to participate or inability to provide written informed consent. * Known hypersensitivity to lidocaine or any component of the infiltration solution. * Heart failure with a left ventricular ejection fraction \< 50%. * Cardiac conduction disorders without an implanted pacemaker. * Uncontrolled epilepsy. * Hepatic or renal insufficiency. * Pregnancy or breastfeeding. * Pre-existing neurological diseases. * Psychiatric disorders. * Preoperative Mini-Mental State Examination (MMSE) score \< 23 points.