A retrospective comparison of percutaneous radiofrequency ablation of osteoid osteoma using three anesthesia modalities
Authors: Di Capua Christopher August , Cabarcas Juan Cotte , Di Capua John F. , Low Sarah , Chang Connie Y. , Gilman Anna J. , Rosenthal Daniel I. , Vazquez Rafael 
Published: October 2020

Objectives:
The objectives of the study were to compare the safety and effectiveness of ultrasound-guided regional anesthesia (USGRA) with monitored anesthesia care (MAC) plus light sedation (MAC + LS) versus MAC with deep sedation (MAC + DS) versus general anesthesia (GA) for percutaneous radiofrequency ablation (PRFA) of lower extremity osteoid osteoma (OO).

Material and Methods:
Patients who underwent PRFA of lower extremity OO from May 2016 to February 2020 were retrospectively reviewed. Three groups were constructed based on the primary anesthetic utilized: (i) USGRA with MAC + LS, (ii) MAC + DS, and (iii) GA. USGRA patients were administered sciatic or tibial nerve blocks using local anesthetic (LA) mixtures consisting of 1.5% mepivacaine ± 2% lidocaine or 2% chloroprocaine. Data were collected on the frequency of conversion to GA, post-procedure ambulatory falls, prolonged neurosensory blockade, technical success of the block, post-procedure visual analog pain scale (VAS), milligram morphine equivalent (MME) administered, procedure and recovery times, and time to resolution of the block. Data were also collected on patient age, sex, and the tumor size and location. Kruskal–Wallis and Pearson’s Chi-squared tests were performed to compare outcomes in the three study groups.

Results:
Nineteen patients (12 men; mean age 20.9 ± 5.9 years) with a median tumor volume of 66 mm3 [IQR 36, 150] were included. Lesion locations included the tibia (10 cases), femur (4 cases), fibula (3 cases), and calcaneus (2 cases). Four patients were provided USGRA and MAC + LS, eight patients underwent MAC + DS, and seven patients received GA. There were no significant differences in patient demographic characteristics between the three study groups. Technical success was achieved in all four patients receiving USGRA. None required conversion to GA, had post-procedure ambulation difficulty, or prolonged neurosensory deficits. Post-procedure VAS score was 0 at all measured time intervals, and no USGRA patients required opioids. Conversely, patients receiving MAC + DS or GA had varying mean VAS scores (GA: 1.8 ± 0.9; MAC + DS: 1.7 ± 1.7) and opioid requirements (median [IQR]) (GA: 0 [0, 0] MME; MAC + DS: 0 [0, 3.75] MME). Tumor volumes >100 mm3 frequently required opioid analgesia. VAS scores were significantly lower in USGRA patients at 30 min post-recovery area arrival (P = 0.027) and on average over 0–120 min post-recovery area arrival (P = 0.016). Procedure duration was similar between the three anesthesia groups (P = 0.939). There was no significant difference in mean recovery times in the USGRA group (230 ± 111 min) compared to the MAC + DS (136 ± 71 min) or GA (113 ± 34 min) groups (P = 0.305). Of note, both time to USGRA resolution (254 min) and recovery time (70 min) were quickest in the patient who received a mixture of 1.5% mepivacaine and 2% chloroprocaine.

Conclusion:
USGRA can be implemented safely and effectively for PRFA of OO as an alternative primary anesthetic technique. It decreases post-procedural discomfort without ambulation difficulty, prolonged neurosensory deficit, or recovery time. The potential for prolonged block duration may be addressed using a mepivacaine/chloroprocaine LA mixture for periprocedural analgesia with quick resolution.