Safety and efficacy of a modified WALANT technique using undiluted adrenaline during open surgical carpal tunnel release: a prospective report of 308 procedures

PURPOSE: The current study aimed to report on the safety and efficacy of utilizing a modified WALANT (mWALANT) technique during open surgical carpal tunnel release (CTR), where we used undiluted epinephrine compared to the originally described WALANT technique. METHODS: From January 2015 till the end of June 2021, 200 patients (175 (87.5%) were females) who presented with carpal tunnel syndrome, either bilateral (108 (54%) patients) or unilateral (92 (46%)) were included, formulating a total of 308 procedures. Open surgical CTR was performed as a daycare procedure by the same surgeon. The mWALANT injectable mixture was prepared by mixing 8 CC of 2% lidocaine HCl + 1 CC of 0.25 mg/1 ml epinephrine without dilution (2.5 times the concentration used in the original WALANT technique). The injection was performed before draping. RESULTS: The patients’ average age at surgery was 42.88 ± 13.03 years old; they were followed up for an average of 31 ± 17.17 months. The average operative time was 9.5 ± 1.87 min. None (0.0%) of the patients needed top-up of local anesthesia or shift into general anesthesia, and no (0.0%) patients needed postoperative hospital stay. The average VAS during the surgical procedure was 2.5 ± 2.1, mainly reported during infiltration of the local anesthesia; no patients reported discomfort during the surgical procedure itself. 180 (90%) patients reported a full return to their usual preoperative ADL after an average of 4.7 ± 1.2 weeks. No (0.0%) postoperative fingers ischemic or temperature changes. Two (1%) patients experienced an adrenaline rush in the form of tachycardia that needed sedation and close monitoring by the anesthesiologist; they were discharged on the same day. One (0.5%) patient (who had uncontrolled diabetes mellitus) showed a superficial wound infection which resolved after conservative management. CONCLUSIONS: Using undiluted epinephrine during the mWALANT technique is safe and effective. There is no need to wait until the drugs fully function, and no epinephrine-related complications were encountered apart from occasional adrenaline rush symptoms.