Background: Subarachnoid blocks are considered routine anesthetic procedures important in the daily practices of most anesthesiologists. However, few data exist regarding modern failure rates or quality-compromising behaviors.

Methods: Sixty adult patients having orthopedic surgery under spinal anesthesia were enrolled in this prospective and observational video study. Through a detailed high definition video review, we aimed to define our subarachnoid block failure rate and identify associated quality-compromising behaviors.

Results: An intrathecal injection either failed to generate a surgical block or was aborted secondary to difficulty in 7 patients (11.6%). A procedurally difficult subarachnoid block occurred in 17 patients (29%). Eight patients required greater than 10 mins of needling to complete the subarachnoid block. Body mass index represented an independent risk factor for long procedure times. There were 27 incidences of quality-compromising behaviors that included likely violation of aseptic technique, hemorrhage, poor positioning, damaged needles, thecal sac transfixation, high-lumbar needle placement, repetition of previously failed maneuvers, failure to provide skin anesthesia, and prolonged procedure times. Certified registered nurse anesthetist status predicted a greater-than-4-fold risk of subarachnoid block failure.

Discussion: The failure rate and quality-compromising behaviors identified in this study challenge the generalized assumption that performing a subarachnoid block in the orthopedic population is a simple procedure. The number and nature of the combined failed and difficult subarachnoid blocks suggest the need for quality improvement. Further research is needed to assess whether the use of image guidance may be a possible solution to navigate difficult anatomical pathology and confirm correct needle and drug placement.