Randomized control trial of a holographic needle guidance technique for thoracic epidural placement.

INTRODUCTION: The Microsoft HoloLens is a head-mounted mixed reality device, which allows for overlaying hologram-like computer-generated elements onto the real world. This technology can be combined with preprocedural ultrasound during thoracic epidural placement to create a visual of the ideal needle angulation and trajectory in the users' field of view. This could result in a technically easier and potentially safer alternative to traditional blind landmark techniques. METHODS: Patients were randomly assigned to one of two groups: (1) HoloLens-assisted thoracic epidural technique (intervention-group H) or (2) traditional thoracic epidural technique (control-group C). The primary outcome was needling time (defined as skin puncture to insertion of epidural catheter) during the procedure. The secondary outcomes were number of needle punctures, number of needle movements, number of bone contacts, and epidural failure. Procedural pain and recovery room pain levels were also evaluated. RESULTS: Eighty-three patients were included in this study. The primary outcome of procedure time was reduced in the HoloLens group compared with control (4.5 min vs 7.3 min, p=0.02, 95% CI), as was the number of needle movements required (7.2 vs 14.4, p=0.01), respectively. There was no difference in intraprocedure or postprocedure pain, bone contacts, or total number of needle punctures. Three patients in the control group experienced epidural failure versus one patient in the HoloLens group. CONCLUSIONS: This study shows that thoracic epidural placement may be facilitated by using a guidance hologram and may be more technically efficient. TRIAL REGISTRATION NUMBER: NCT04028284.

Development of a Head-Mounted Holographic Needle Guidance System for Enhanced Ultrasound-Guided Neuraxial Anesthesia: System Development and Observational Evaluation.

BACKGROUND: Neuraxial anesthesia is conventionally performed using a landmark-based technique. Preprocedural ultrasound is often used in challenging clinical scenarios to identify an ideal needle path. The procedure is then carried out by the operator recreating the ultrasound needle path from memory. We suggest that a needle guidance system using the Microsoft HoloLens mixed reality headset, which projects a hologram of the ideal needle path, can assist operators in replicating the correct needle angulation and result in fewer needle passes. OBJECTIVE: The objective of the study was to develop software for the mixed reality HoloLens headset, which could be used to augment the performance of neuraxial anesthesia, and establish its face validity in lumbar spine phantom models. METHODS: We developed an ultrasound transducer marker and software for the HoloLens, which registers the position and angulation of the ultrasound transducer during preprocedural scans. Once an image of a clear path from skin to the intrathecal space is acquired, a hologram of the ideal needle path is projected onto the user's visual field. The ultrasound probe is removed while the hologram remains in the correct spatial position to visualize the needle trajectory during the procedure as if conducting real-time ultrasound. User testing was performed using a lumbar spine phantom. RESULTS: Preliminary work demonstrates that novice (2 anesthesia residents) and experienced operators (5 attending anesthesiologists) can rapidly learn to use mixed reality holograms to perform neuraxial anesthesia on lumbar spine phantoms. CONCLUSIONS: Our study shows promising results for performing neuraxial anesthesia in phantoms using the HoloLens. Although this may have wide-ranging implications for image-guided therapies, further study is required to quantify the accuracy and safety benefit of using holographic guidance. TRIAL REGISTRATION: ClinicalTrials.gov NCT04028284; https://clinicaltrials.gov/ct2/show/NCT04028284.

Comparison of the effects of perineural or intravenous dexamethasone on low volume interscalene brachial plexus block: a randomised equivalence trial.

BACKGROUND: Efforts to prolong interscalene block (ISB) analgesia include the use of local anaesthetic adjuvants such as dexamethasone. Previous work showing prolonged block duration suggests that both perineural and intravenous (i.v.) routes can both prolong analgesia. The superiority of either route is controversial given the design of previous studies. As perineural dexamethasone is an off-label use, anaesthesiologists should be fully informed of the clinical differences, if any, on block duration. This study was designed to test whether perineural vs i.v. dexamethasone administration are equivalent. METHODS: We randomised 182 eligible patients scheduled for arthroscopic shoulder surgery to receive low-dose ISB (0.5% ropivacaine 5 ml) with perineural or i.v. dexamethasone 4 mg. Subjects, anaesthesiologists, and research personnel were blinded. All subjects also received a standardised general anaesthetic and multimodal analgesia. The primary outcome was duration of analgesia analysed as an equivalence outcome (2 h equivalency margin) using the two one-sided test (TOST) method. RESULTS: For the primary outcome, duration of analgesia, and perineural and i.v. administration of dexamethasone were not equivalent. The upper and lower bounds of the 90% confidence interval were 1 h (P=0.12) and -2.5 h (P=0.01), respectively. The observed difference in mean block duration was not clinically relevant (0.75 h longer for i.v. dexamethasone). There were no other clinically significant differences between groups. CONCLUSION: In the context of low-volume ISB with ropivacaine, perineural and i.v. dexamethasone were not equivalent in terms of their effects on block duration. However, there were no clinically significant differences in outcomes, and there is no advantage of perineural over intravenous dexamethasone. WWW.CLINICALTRIALS. GOV REGISTRATION: NCT02322242.

Thoracic Epidural Catheter Placement in a Preoperative Block Area Improves Operating Room Efficiency and Decreases Epidural Failure Rate.

BACKGROUND AND OBJECTIVES: The primary aim of this study was to review the impact of inserting thoracic epidural catheters in a preoperative block room setting on operating room efficiency. METHODS: We conducted a retrospective preintervention/postintervention review of thoracic epidurals inserted over a 12-month period. The review included 6 months of data prior to implementation of the regional anesthesia block room and 6 months of data following implementation. The primary outcome measure was anesthesia-controlled operating room time, defined as time from patient arrival to the operating room to time of surgical site sterile preparation. Secondary measures included operating room waiting time for the patient arrival, thoracic epidural failure rate, and number of epidural insertion attempts. RESULTS: Data from thoracic epidurals for 112 patients of preblock room and 142 patients of postblock room implementation were collected. Anesthesia-controlled operating room time was reduced by an average of 22.9 minutes per patient (95% confidence interval, 19.3-26.3 minutes; P < 0.01). Average operating room waiting time for patient arrival increased by 3.8 minutes (95% confidence interval, 1.0-6.5 minutes; P < 0.01), resulting in net operating room time savings of 19.1 minutes per epidural. The epidural failure rate decreased from 16.0% to 5.6% (P < 0.01). There was no difference in the number of epidural insertion attempts made per patient. CONCLUSIONS: Insertion of thoracic epidural analgesia in a preoperative block room setting can significantly reduce anesthesia-controlled operating room time and epidural failure rates.