Effect of Intravenous Ketamine Combined With Spinal Anesthesia on Sensory Block Duration Compared to Spinal Anesthesia Alone in Lower Limb Surgeries in Geriatrics.

Inclusion Criteria: * Patients aged 65 years and older * Both sexes * American Society of Anesthesiologists (ASA) physical status I, II, III * Scheduled for elective lower limb surgeries under spinal anesthesia in supine position Exclusion Criteria: * Patient's refusal. * Pre-existing neurological disorders. * Coagulopathy (i.e., Platelets ≤ 60,000 and/or INR\> 1.5). * Localized infection at the site of needle insertion. * Known hypersensitivity or allergies to any of the used drugs