Efficacy of Local Anesthesia in the Face and Scalp

A Prospective Trial

Tyler Safran, MD; Dino Zammit, MD; Jonathan Kanevsky, MD, FRCSC; Manish Khanna, MD, FRCPC

Disclosures

Plast Reconstr Surg Glob Open. 2019;7(5):e2243 

In This Article

Abstract and Introduction

Abstract

Background: The use of local anesthesia has allowed for the excision and repair of lesions of the head and neck to be done in an office-based setting. There is a gap of knowledge on how surgeons can improve operative flow related to the onset of action. A prospective trial was undertaken to determine the length of time for full anesthesia effect in the head and neck regions.

Methods: Consecutive patients undergoing head and neck cutaneous cancer resection over a 3-month period were enrolled in the study. Local anesthesia injection and lesion excision were all done by a single surgeon. All patients received the standard of care of local anesthesia injection.

Results: Overall, 102 patients were included in the prospective trial. The upper face took significantly longer (153.54 seconds) compared with the lower face and ears (69.37 and 60.2 seconds, respectively) (P < 0.001) to become fully anesthetized. In addition, there was no significant difference found when adjusting for the amount of local anesthesia used, type, and size of lesion (P > 0.05). Using the time to full anesthesia effect for each local injection, a heat map was generated to show the relative times of the face and scalp to achieve full effect.

Conclusions: This prospective trial demonstrated that for the same local anesthetic and concentration, upper forehead and scalp lesions take significantly longer to anesthetize than other lesions in the lower face and ear. This can help surgeons tailor all aspects of their practice, which utilizes local anesthesia to help with patient satisfaction and operative flow.

Introduction

The excision and repair of cutaneous cancers of the head and neck is predominantly performed in office-based procedure rooms under local anesthesia. The appeal of using local anesthesia is due to the minimal downtime and avoidance of postoperative hospitalization or observation. In addition, the benefits of local anesthesia include ease of administration, rapid onset of action, and do not require the services of an anesthesiologist. Despite the low rate of complications and well-studied safety profile, its administration is a source of significant anxiety to patients.[1] In some cases, even more than the procedure itself. Both patients and surgeons equally wish to ensure adequate anesthesia for the entire duration of the procedure.

To this effect, a breadth of evidence exists that is dedicated to the art and science of local anesthesia to increase its effectiveness and duration while minimizing the pain of injection.[2] This includes, but is not limited to, buffering the anesthetic solution, adding epinephrine, warming the anesthetic, and patient distraction on injection, thereby leveraging the gate theory of pain.[2,3] A recurrent topic of discussion in the literature is improving the time of onset, thereby improving operative flow and avoiding the need to have significant blocks of time dedicated to reassessing the anesthesia. Certain regional blocks in the head and neck can be quite difficult to perform, especially if the clinician is not familiar with the complex anatomy. With this in mind, surgeons often perform a ring block: using infiltrative local anesthesia around and beneath the lesion in the subdermal/adipose plane.

The trigeminal nerve contributes a majority of the robust sensory nerve distribution to the face and scalp.[4] The trigeminal nerve yields 3 branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3).[4] Recently, with the advent of migraine surgery and improved techniques in facial reconstruction and rejuvenation, the trigeminal nerve has been extensively studied, yielding new branches and cutaneous nerves that were not previously identified, such as the accessory nerves of the forehead.[5] Through anatomical studies, it has been shown that the volume and quantity of main branches of the trigeminal nerve decrease in the cranial direction.[5,6] Building on this concept, when performing head and neck cutaneous cancer excisions, the authors of the present study noticed that lesions in the mid-forehead and scalp took significantly longer for the local anesthesia to take effect. The question became, why did lesions in this region take longer to achieve anesthesia?

To address this clinical question and attempt to optimize local anesthesia administration in this patient population, the authors designed a prospective trial of head and neck cutaneous cancer patients undergoing an excision under local anesthesia. Armed with this information, surgeons will be better suited to tailor the anesthetic demands of procedures in this anatomical region.

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