Spine surgery often causes severe postoperative pain. Currently, our hospital routinely uses ropivacaine for local infiltration analgesia (lasting 6-8 hours). This study evaluates liposomal bupivacaine, a novel long-acting local anesthetic providing up to 72 hours of pain relief, in patients undergoing posterior lumbar spine surgery. Through a randomized controlled design, we will compare the two drugs' effects on pain control within 72 hours and opioid consumption. Both regimens are guideline-recommended and safe.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
204
Patients will receive a pre-closure local infiltration of 266 mg liposomal bupivacaine (20 mL for single-level surgery; 30 mL for two-level surgery) combined with 25 mg bupivacaine hydrochloride (10 mL total volume). The drug will be injected bilateral into the paraspinal muscles and subcutaneous tissues prior to wound closure. This provides both immediate (bupivacaine HCl) and prolonged (liposomal) analgesia."
Patients will receive 120 mg ropivacaine diluted to 30 mL (single-level) or 40 mL (two-level) with normal saline. The solution will be infiltrated bilateral into the paraspinal muscles and subcutaneous tissues using the same technique as the experimental arm, ensuring consistent injection depth and distribution.
Peking University Third Hospital
Beijing, China
RECRUITINGTotal opioid consumption within 72 hours postoperatively (converted to morphine milligram equivalents, MME)
Opioid doses will be converted to MME using the CDC standard conversion table
Time frame: 72 hours postoperative
Postoperative pain intensity assessed by Numeric Rating Scale (NRS, 0-10) at rest and during movement (e.g., coughing/ambulation) at predefined timepoints: pre-PACU discharge, 4h, 8h, 24h, 48h, and 72h after surgery.
NRS ranges from 0 (no pain) to 10 (worst imaginable pain). Movement-associated pain will be assessed during standardized activities (e.g., coughing on command or first ambulation).All assessors will be trained to ensure consistent NRS measurement across timepoints. Daytime assessments: Performed within ±30 minutes of scheduled timepoints Nighttime adjustments: Assessments falling between 21:00 (9:00 PM) and 07:00 (7:00 AM) will be deferred to 08:00 AM the following morning to avoid sleep disruption. Original timepoints documented with annotations (e.g., "Scheduled: 02:00; Assessed: 08:00+1")
Time frame: Immediately prior to PACU discharge，4 hours, 8 hours, 24 hours, 48 hours, and 72 hours after surgery.
Total postoperative morphine consumption via PCA
PCA settings will be standardized across all patients: * Bolus dose: 1 mg morphine equivalent * Lockout interval:10 minutes * No background infusion.
Time frame: Cumulative consumption recorded at 4 hours, 8 hours, 24 hours, 48 hours, and 72 hours after surgery
Total Postoperative Rescue Tramadol Consumption
Trigger Criteria: NRS \>3 at rest despite PCA morphine (1mg bolus, 10min lockout). Dosing Protocol: Tramadol 50mg IV/oral Data Collection: Cumulative tramadol consumption recorded at 4hours, 8hour, 24hours, 48hours, 72hours after surgery. Convert oral to IV equivalent for analysis
Time frame: From PCA initiation until 72 hours (Day3) postoperatively. Rescue tramadol consumption will be recorded at 4hours, 8hour, 24hours, 48hours, 72hours after surgery.
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Sleep disturbance due to pain (binary scale)
Patients will report whether pain interfered with sleep during the previous night using a standardized binary scale: * 0: No sleep disruption (pain did not awaken or prevent sleep) * 1: Sleep disrupted (pain caused awakening or difficulty falling asleep). Assessment Protocol: Evaluated each morning at 8:00 AM by trained research staff Covers sleep quality during the preceding night (20:00-07:59) Delayed assessment for nighttime surgeries: If surgery ends after 18:00, first assessment deferred to 8:00 AM on postoperative Day 1
Time frame: Postoperative Days 1 (24 hours), 2 (48 hours), and 3 (72 hours), with daily assessment window: 8:00-9:00 AM
Time to first independent ambulation
Definition: Hours from surgery end to first unassisted walking \>5 meters
Time frame: From surgery completion until event occurs, assessed up to 72 hours postoperatively
Immediate local anesthetic-related complications (0-2 hours)
All complications will be recorded and graded. Immediate events (0-2h): * Local anesthetic systemic toxicity (LAST): CNS/CV symptoms (e.g., seizures, arrhythmias) * Allergic reactions: urticaria, bronchospasm, anaphylaxis
Time frame: From local anesthetic infiltration completion through 2 hours post-procedure.
Incidence of nausea/vomiting (PONV)
Graded by severity: 1=Mild (no rescue), 2=Moderate (required 1 antiemetic), 3=Severe (≥2 antiemetics or prolonged NPO). Standardized Assessment Protocol at fixed timepoints: Day 1: 0-24 hours postoperatively Day 2: 24-48 hours postoperatively Day 3: 48-72 hours postoperatively Assessment window: Performed daily at 08:00 AM for previous 24-hour period Evening surgeries (end time \>18:00): First assessment at 08:00 AM on Day 1 Symptom tracking: Nursing staff document all emetic episodes and antiemetic administrations in real-time
Time frame: From surgery completion through 72 hours (Day 3) postoperatively, with interval reporting: 0-24 hours (Day 1), 24-48 hours (Day 2), 48-72 hours (Day 3).
Pruritus severity
Rated by patients: 0=None, 1=Mild (no treatment), 2=Moderate (topical therapy), 3=Severe (systemic treatment).
Time frame: From surgery completion through 72 hours (Day 3) postoperatively, with interval analyses: 0-24 hours (Day 1)，24-48 hours (Day 2)，48-72 hours (Day 3)
Incidence of Postoperative Urinary Retention Requiring Catheterization
Definition \& Assessment Protocol: Diagnostic Criteria: Bladder volume ≥600 mL (ultrasound-confirmed) + inability to void spontaneously. Catheterization threshold: Pain (VAS ≥4) with bladder volume ≥600 mL, OR No voiding for 8 hours + bladder volume ≥400 mL. Data Collection: Event-driven assessments: Triggered by patient-reported symptoms. Maximum observation period: 72 hours (Day 3).
Time frame: From surgery completion through 72 hours (Day 3) postoperatively, with planned intervals: 0-24 hours (Day 1), 24-48 hours (Day 2), 48-72 hours (Day 3).
Postoperative Sedation Levels Assessed by Ramsay Scale
Ramsay Scale: 1. Patient anxious/agitated 2. Cooperative/oriented 3. Responds to commands only 4. Asleep but brisk response to stimulus 5. Sluggish response 6. No response. Scoring Direction: Higher scores indicate deeper sedation (1=inadequate, 6=excessive). Clinical Thresholds: Target range: RSS 2-4 (ERAS-recommended optimal sedation) Intervention triggers: RSS ≥5 (reduce sedation), RSS ≤1 (rescue analgesia) Assessment Protocol Fixed Timepoints: 4 hours (Postoperative Day 0) 8 hours (Postoperative Day 0) 24 hours (Postoperative Day 1) 48 hours (Postoperative Day 2) 72 hours (Postoperative Day 3) Nighttime Adjustment: Assessments between 21:00-07:00 deferred to 08:00 next morning Data Collection Window: ±30 minutes at each timepoint Standardized Stimuli: Verbal: "Open your eyes" at 70 dB Tactile: Shoulder shaking with 500g pressure
Time frame: From anesthesia emergence until 72 hours postoperatively, at Fixed timepoints: 4 hours, 8 hours, 24 hours, 48 hours and 72 hours after surgery.
Incidence of Postoperative Delirium Assessed by 3D-CAM (3-Minute Diagnostic Interview for CAM-Defined Delirium)
3D-CAM assesses: 1) Acute onset, 2) Inattention, 3) Disorganized thinking, 4) Altered consciousness. Administered by trained research assistants blinded to group allocation. Primary Assessment Points: 24 hours (Postoperative Day 1) 48 hours (Postoperative Day 2) 72 hours (Postoperative Day 3) Evaluation Window: ± 30 min at each timepoint. Nighttime detections (21:00-07:00) formally assessed at 08:00 next morning
Time frame: From anesthesia emergence through 72 hours postoperatively: Primary Assessment Points: 24 hours (Postoperative Day 1) 48 hours (Postoperative Day 2) 72 hours (Postoperative Day 3)
PCA demand attempts
Unit of Measure: Number of attempts
Time frame: Counted over consecutive intervals: 0-4 hours, 4-8 hours, 8-24 hours, 24-48 hours, and 48-72 hours postoperatively
PCA delivery/demand ratio
Calculation: (Number of successful PCA deliveries / Number of PCA demand attempts) × 100
Time frame: Calculated for each interval: 0-4hours, 4-8hours, 8-24hours, 24-48hhours, 48-72hours after surgery.
Time to first PCA attempt
Time frame: Recorded from end of surgery until first PCA button press
Time to first tolerated oral intake
Definition: Hours from surgery end to first clear liquid intake (≥50 mL) without vomiting within 30 minutes
Time frame: From PACU discharge until event occurs, assessed up to 48 hours postoperatively
Time to first bowel movement
Definition: Hours from surgery end to first flatus or defecation reported by patient
Time frame: From surgery completion until event occurs, assessed up to 7 days postoperatively
Postoperative length of stay
Definition: Days from surgery end to hospital discharge (excluding preoperative days)
Time frame: From surgery completion until discharge, assessed up to 14 days postoperatively
Delayed local anesthetic-related complications (24-72 hours)
Definition: Complications manifesting 24-72 hours postoperatively Subcategories: 1.Wound Complications: 1. Infection: CDC criteria (purulent drainage + ≥1: erythema, pain, swelling) 2. Hematoma: Ultrasound-confirmed collection \>5 mL + hemoglobin drop ≥1 g/dL 3. Neurological Injury 2.Persistent deficit: Sensory/motor dysfunction beyond 72 hours Confirmed by: Day 3: Nerve conduction studies (amplitude reduction \>50%). Day 7: EMG if symptoms persist Assessment Schedule: Fixed timepoints: 24h (Day 1), 48h (Day 2), 72h (Day 3) at 08:00 AM Symptom-driven: Any clinical suspicion triggers immediate evaluation
Time frame: Any clinical suspicion triggers immediate evaluation from 24 hours (Day 1) through 72 hours (Day 3) postoperatively