Overview
The goal of this observational study is to compare spinal anaesthesia success in adults with and without previous lower back surgery. The main question it aims to answer is:
\- Does previous lower back surgery affect the success of spinal anaesthesia on the first needle insertion?
Participants will receive spinal anaesthesia as part of their usual medical care. Researchers will record needle attempts, procedure time, and anaesthesia effectiveness. Participation will not involve additional procedures or changes to routine care.
Description
Previous lumbar spine surgery can alter anatomical landmarks and produce scar tissue that may make spinal anaesthesia technically more difficult. This study will examine the association between prior lumbar surgery and technical performance during routine spinal anaesthesia.
Patients will be grouped according to whether they have a history of lumbar spine surgery. Anaesthesia decisions will be made by treating clinicians who are not involved in research data collection. No anaesthetic technique or treatment will be assigned by the researchers.
Demographic and clinical characteristics, previous lumbar surgery details, and procedural observations will be collected prospectively using a standardized form. This will allow technical difficulties to be examined alongside block characteristics and early hemodynamic changes.
An internal pilot phase will include 25 patients in each group. Pilot estimates of first-insertion success will inform the sample size calculation for the main study. Group-specific success rates and their absolute difference will be reported with 95% confidence intervals.
Eligibility
Inclusion Criteria:
- Age 18 years or older.
- American Society of Anaesthesiologists (ASA) physical status classification I-III.
- Scheduled to receive clinically indicated spinal anaesthesia for surgery, performed by clinicians other than the researchers collecting study data.
- Provision of written informed consent.
Exclusion Criteria:
- Any clinical contraindication to spinal anaesthesia.
- Refusal to participate or inability to provide written informed consent.
- Severe cognitive impairment preventing study assessments.
- Planned epidural or combined spinal-epidural anaesthesia.
- Inability to reliably record study data.
