At the preoperative visit, patients will sign informed consent and learn to use the patient-controlled analgesia (PCA) pump and assess pain with the visual analogue scale (VAS). Standard general anesthesia will be induced and maintained with sufentanil, propofol, cisatracurium or rocuronium, and sevoflurane. Before incision, neurosurgeons will administer the allocated local infiltration solution. 0.375ml of diprospan will be diluted to 30 ml with 15 ml of ropivacaine in 0.9% NaCl to prepare diprospan at concentrations of 0.009%, respectively. The surgeon will use a 22 G straight needle for local infiltration anesthesia near the planned incisions. Postoperatively, patients will receive tropisetron and a PCA pump delivering sufentanil and ondansetron. PCA usage (effective/ineffective presses) and supplemental analgesia with Tylenol or loxoprofen will be monitored for 48 hours and up to 3 months. Dosages and intraoperative parameters will be closely recorded throughout.

At the preoperative visit, patients will sign informed consent and learn to use the patient-controlled analgesia (PCA) pump and assess pain with the visual analogue scale (VAS). Standard general anesthesia will be induced and maintained with sufentanil, propofol, cisatracurium or rocuronium, and sevoflurane. Before incision, neurosurgeons will administer the allocated local infiltration solution. 0.25ml of diprospan will be diluted to 30 ml with 15 ml of ropivacaine in 0.9% NaCl to prepare diprospan at concentrations of 0.006%, respectively. The surgeon will use a 22 G straight needle for local infiltration anesthesia near the planned incisions. Postoperatively, patients will receive tropisetron and a PCA pump delivering sufentanil and ondansetron. PCA usage (effective/ineffective presses) and supplemental analgesia with Tylenol or loxoprofen will be monitored for 48 hours and up to 3 months. Dosages and intraoperative parameters will be closely recorded throughout.

At the preoperative visit, patients will sign informed consent and learn to use the patient-controlled analgesia (PCA) pump and assess pain with the visual analogue scale (VAS). Standard general anesthesia will be induced and maintained with sufentanil, propofol, cisatracurium or rocuronium, and sevoflurane. Before incision, neurosurgeons will administer the allocated local infiltration solution. 0.125ml of diprospan will be diluted to 30 ml with 15 ml of ropivacaine in 0.9% NaCl to prepare diprospan at concentrations of 0.003%, respectively. The surgeon will use a 22 G straight needle for local infiltration anesthesia near the planned incisions. Postoperatively, patients will receive tropisetron and a PCA pump delivering sufentanil and ondansetron. PCA usage (effective/ineffective presses) and supplemental analgesia with Tylenol or loxoprofen will be monitored for 48 hours and up to 3 months. Dosages and intraoperative parameters will be closely recorded throughout.

At the preoperative visit, patients will sign informed consent and learn to use the patient-controlled analgesia (PCA) pump and assess pain with the visual analogue scale (VAS). Standard general anesthesia will be induced and maintained with sufentanil, propofol, cisatracurium or rocuronium, and sevoflurane. Before incision, neurosurgeons will administer the allocated local infiltration solution. 15 ml of ropivacaine will be diluted to 30 ml with in 0.9% NaCl, respectively. The surgeon will use a 22 G straight needle for local infiltration anesthesia near the planned incisions. Postoperatively, patients will receive tropisetron and a PCA pump delivering sufentanil and ondansetron. PCA usage (effective/ineffective presses) and supplemental analgesia with Tylenol or loxoprofen will be monitored for 48 hours and up to 3 months. Dosages and intraoperative parameters will be closely recorded throughout.

PONV will be rated by participants as: 0, absent; 1, nausea not requiring treatment; 2, nausea requiring treatment; and 3, vomiting.

Ramsey 1: Anxious, agitated, restless; Ramsey 2: Cooperative, oriented, tranquil; Ramsey 3: Responsive to commands only If Asleep; Ramsey 4: Brisk response to light glabellar tap or loud auditory stimulus; Ramsey 5: Sluggish response to light glabellar tap or loud auditory stimulus; Ramsey 6: No response to light glabellar tap or loud auditory stimulus.

0 for unsatisfactory, and 10 for very satisfied

Higher scores indicate a better perception of quality of life.

The Oswestry Disability Index (ODI) is a widely used tool to measure disability related to lower back pain. It consists of 10 sections, each addressing different aspects of daily life affected by back pain. Higher scores mean more severe pain.

The Patient and Observer Scar Assessment Scale (POSAS) is a widely used tool for assessing scars from both the patient's and observer's perspectives. It evaluates scar quality based on physical characteristics and the patient's subjective experience. Lower scores indicate better scar quality and fewer issues. Higher scores reflect worse scar quality or greater subjective dissatisfaction.