A comparative study on the difficulty of fine-needle spinal anesthesia and "needle-through-needle" spinal anesthesia procedures

INTERVENTION: Experimental group(single‐shot fine‐needle spinal anesthesia group):Use a fine needle for spinal anesthesia and directly perform the puncture.;Control group (conventional needle‐through‐needle single‐shot spinal anesthesia group):Single‐shot subarachnoid block (spinal anesthesia) was performed using the needle‐through‐needle technique.; CONDITION: None PRIMARY OUTCOME: Puncture success time, defined as the time interval from skin puncture to confirmation of free‐flowing cerebrospinal fluid (CSF); SECONDARY OUTCOME: Comparison of hemodynamic parameters (blood pressure, heart rate) after the anesthetic procedure;First‐attempt puncture success rate;Total puncture time;The incidence of postoperative adverse reactions;Number of needle insertions;Final puncture success rate;Pain score during puncture; INCLUSION CRITERIA: 1.Preoperative anesthesia risk assessment: ASA grade I ‐ III; 2.Patients aged 18–69 years, of either sex, with a body mass inde X(BMI) <30 kg/m^2, who voluntarily agreed to participate in this study and provided written informed consent. 3.Patients with an anticipated operative time of less than 2 hours and intrathecal anesthesia as the planned anesthetic technique.