This study aims to address these gaps by comparing the incidence of TCR during septoplasty performed using cold dissection versus electrocautery, while also incorporating a novel assessment of surgical force.

Septoplasty is one of the most commonly performed otorhinolaryngological procedures and is generally considered safe . However, it may be associated with rare but potentially serious autonomic reflexes, most notably the trigeminal cardiac reflex (TCR) . The TCR is a brainstem reflex characterized by sudden parasympathetic activation resulting in bradycardia, hypotension, arrhythmias, or even asystole following stimulation of the trigeminal nerve or its branches. Clinically, TCR is usually defined as a sudden reduction in heart rate exceeding 20% from baseline during trigeminal nerve stimulation . The trigeminal nerve provides rich sensory innervation to the nasal septum, particularly in the posterior septal region and near the sphenopalatine area. Surgical manipulation in these areas during septoplasty can trigger TCR, especially when the stimulus is intense or prolonged . While TCR has been extensively reported in neurosurgical, maxillofacial, and skull base procedures, its occurrence during nasal surgery is increasingly recognized but remains underreported and underinvestigated .

Several factors are believed to influence the incidence and severity of TCR, including the type, intensity, and duration of trigeminal stimulation. Both mechanical stimulation, such as traction, pressure, or fracture of bone and cartilage, and thermal stimulation, such as electrocautery, can activate trigeminal afferents . Experimental and clinical observations suggest that thermal stimulation may produce a stronger and more sustained trigeminal response compared to mechanical manipulation alone, potentially leading to a higher incidence of TCR . Despite the widespread use of electrocautery for dissection and hemostasis during septoplasty, there is limited evidence directly comparing its impact on TCR incidence with that of cold steel dissection techniques. Cold dissection relies primarily on mechanical separation using scissors, chisels, and elevators, avoiding thermal injury to surrounding tissues and neural endings. Whether this difference in stimulus modality translates into a clinically significant difference in TCR incidence has not been systematically evaluatedData analysis will be carried out using SPSS (IBM SPSS Statistics) and/or R.

Continuous variables will be expressed as mean ± standard deviation (SD) when normally distributed, or as median with interquartile range for non- normally distributed data. Categorical variables will be summarized as frequencies and percentages. A p-value of less than 0.05 (two-tailed) will be considered statistically significant. Group comparisons will be conducted using: Independent samples t-test for normally distributed continuous data, Mann-Whitney U test for skewed continuous data, Chi-square test or Fisher's exact test for categorical data.

Inclusion Criteria:

• Age 18-60 years.
• Indicated for primary septoplasty.
• American Society of Anesthesiologists (ASA) physical status I-II.

Exclusion Criteria:

• History of cardiac arrhythmias or conduction abnormalities.
• Use of beta-blockers, calcium channel blockers, or antiarrhythmic drugs Previous nasal surgery.
• Combined nasal procedures.
• Intraoperative complications requiring deviation from the assigned technique.

Randomization and Group Allocation Patients will be randomly allocated into two groups using computer-generated randomization: