Early Mobilization Following Elective Spine Surgery: Trial of In-bed Cycling

Inclusion Criteria Male or female ≥ 18 years old. Postoperative #0 following elective spinal surgery: decompression with or without fusion, or fusion. Patient able to walk independently before surgery (does not require assistance from another person and does not use a wheelchair). Patient admitted directly from the operating room to the ward. Hemodynamically stable: Systolic blood pressure (SBP): ≥ 90 mmHg and \< 140 mmHg Oxygen saturation \> 94% Heart rate: 50-100 bpm Patient approved for surgery after preoperative internal medicine evaluation. Patient alert and conscious. Valid informed consent obtained. Exclusion Criteria Non-ambulatory preoperatively. Body Mass Index (BMI) \> 40 kg/m². Acute neurological spinal trauma. Non-neurological musculoskeletal impairment of the lower limbs (e.g., severe osteoarthritis, hip fracture, amputation) limiting the ability to pedal in bed. Uncontrolled comorbidities preventing surgery or intervention (cardiovascular, respiratory, diabetes). Expected hospital stay of less than 2 days after surgery. Surgery-related complications: acute neurological deficit, dural tear, cerebrospinal fluid (CSF) leak, residual spinal instability. Transfer to intensive care unit or hemodynamic instability. Persistent hemodynamic instability: SBP \< 90 mmHg or \> 200 mmHg, oxygen saturation \< 88%, heart rate \< 50 or \> 100 bpm, temperature \> 38°C. Capillary blood glucose outside target values: \< 4.0 or \> 7.0 mmol/L fasting or pre-mea…