Investigators aimed to determine the rates of unsuccessful spinal anesthesia, to determine the factors related to failure and to determine the measures that may be taken to reduce this problem.

The study is as a cross-sectional, prospective, observational. After institutional review board approval and informed written consent, all patients aged ≥ 18 years undergoing spinal anesthesia in the Izmir Bozyaka Training and Research Hospital Operating Room will be included in the study. The specialist and assistant physician in charge of spinal anesthesia management of patients will undertake their own routine anesthesia management and the researcher will not be involved in any way. Patients who underwent combined spinal-epidural anesthesia and patients without consent were excluded. The primary aim of the study was to determine the rate of unsuccessful spinal anesthesia (total failure and partial failure) and to determine the factors that may be associated with these. Total failure was described as failure of localization of subarachnoid space with lumbar puncture; no motor and / or sensory block occurring within 10 minutes after the injection of local anesthetic into the subarachnoid space; repeated spinal anesthesia or general anesthesia. Partial failure was described as the need for anesthetic agents such as ketamine, propofol or opioid for the intraoperative pain relief, except for the use of midazolam and fentanyl in order to increase the patient's comfort.The secondary aim of the study was to determine the first attempt success and related factors. The first attempt success was described as identification or subarachnoid space at the first attempt.

Parameters to be recorded during the study are: age, gender, weight, height, body mass index (BMI), American Society of Anesthesiologist (ASA) status, type of surgery, elective / emergency surgery, patient's body type, spinal anatomy, position of the patient and the practitioner during spinal intervention, the technique applied (median /paramedian), the level of puncture, the type of spinal needle, the direction of the spinal needle notch, the number of spinal puncture, the nature of the cerebrospinal fluid (CSF) (clear/haemorrhagic), whether or not aspiration is performed, whether or not free CSF is controlled before or after drug injection, whether the practitioner is an expert or assistant, the assistant is seniority year, the type of local anesthetic, if the adjuvant drug is added to the local anesthetic, the dose of anesthetic, the loss of drug during injection of local anesthesia, position of the patient after injection, duration of surgery, testing of motor and sensory block, what is done in case of unsuccessful spinal anesthesia, examination of sacral dermatomes prior to second spinal anesthesia intervention will be recorded. Parameters will be recorded by Anesthesia Specialist, Anesthesia Assistant or Anesthesia Technician. At the end of the case, the registration form will be left at the designated place in the Anesthesia Clinic room.

Inclusion Criteria:

1. Patients aged ≥ 18 years who are undergoing spinal anesthesia in Izmir Bozyaka Training and Research Hospital during study period.
2. American Society of Anesthesiologist Physical Status classification (ASA) I-IV.

Exclusion Criteria:

1. Patients who are undergoing combined spinal-epidural anesthesia.

All patients aged ≥ 18 years undergoing spinal anesthesia in the Izmir Bozyaka Training and Research Hospital Operating Room will be included in the study.