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Year : 2018  |  Volume : 22  |  Issue : 1  |  Page : 26-27

Geometric evaluation of a fundamental surgical technique

Department of Dermatology, Des Moines University, Des Moines, Iowa, USA

Date of Web Publication31-Jan-2018

Correspondence Address:
Dr. Timothy Nyckowski
3200 Grand Ave. Des Moines, IA 50312
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdds.jdds_10_18

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How to cite this article:
Nyckowski T. Geometric evaluation of a fundamental surgical technique. J Dermatol Dermatol Surg 2018;22:26-7

How to cite this URL:
Nyckowski T. Geometric evaluation of a fundamental surgical technique. J Dermatol Dermatol Surg [serial online] 2018 [cited 2022 May 17];22:26-7. Available from: https://www.jddsjournal.org/text.asp?2018/22/1/26/224388

Dermatologists perform more office-based cutaneous surgery than any other specialty.[1] Despite the numerous variables, surgeons are relatively uniform in abiding by proper surgical technique.[2] One particular consistency in surgical technique, often taught as a fundamental surgical concept in medical school, is the manner in which the needle point is recommended to be brought to the site of tissue repair. Specifically, several surgical techniques state that the needle should first bite the tissues perpendicular to the epidermis and the needle should follow a circular path as defined by the needle's natural curvature.[1],[3] The reasoning behind this approach has been mechanical: this technique of tissue entry and subsequent natural trajectory of the needle curvature minimizes the wrench between the tissue and the needle.[3] Put simply, this technique is intended to minimize tissue damage. While this may hold true, stringently following this technique would lead to the needle bites being too large for cutaneous application, ultimately resulting in poor tissue cosmesis. This method of tissue entry has been taught so ubiquitously in surgery throughout the years; some may accept it as fact and apply it to cutaneous surgery.

Given this technique of tissue penetration, a curved needle would have a bite size equal to the diameter of the completed circle defined by the curve of the needle [Figure 1]. The arc length of any given needle can be provided by the manufacturer. The majority of skin suturing is done with a needle with an arc length that is 3/8 of a circle.[1] Consider the following equation, using a 13-mm arc length needle, for example, where c is the circumference of the circle and d is the diameter of the circle:
Figure 1: Schematic representing 3/8 arc length needle penetrating cutaneous tissue

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  1. c = d π

  2. 34.67 mm = d π

  3. 11mm ≈ d bite size.

Given the semicircular trajectory encouraged by supination/pronation of the wrist, the average needle bite size is about 11 mm. The actual bite size varies based on needle size (e.g., PS-2 vs. PS-3), but rarely in our clinical practice do we take 11 mm bites in cutaneous surgery.[3] Among the listed options for needle arc length on a manufacturer's website, 13 mm was the smallest size that could be found for the cosmetic or cutaneous suture.[4] This means that larger needle sizes would lead to even greater discrepancies between sound surgical technique and cutaneous surgical techniques used in practice.

Thus, we find that even though there is consensus among recommended suturing approach on paper, this practice is inconsistent with what occurs in the hand of the cutaneous surgeon. Perhaps, the previously delineated surgical technique of perpendicular approach to the tissue followed by pronation/supination to the curvature of the needle until tissue exit is merely a convenient surgical concept in the realm of platonic forms, when applied to the skin.

  References Top

Miller CJ, Antunes MB, Sobanko JF. Surgical technique for optimal outcomes: Part II. Repairing tissue: Suturing. J Am Acad Dermatol 2015;72:389-402.  Back to cited text no. 1
Adams B, Levy R, Rademaker AE, Goldberg LH, Alam M. Frequency of use of suturing and repair techniques preferred by dermatologic surgeons. Dermatol Surg 2006;32:682-9.  Back to cited text no. 2
Jackson RC, Cavuşoǧlu MC. Needle path planning for autonomous robotic surgical suturing. IEEE Int Conf Robot Autom 2013;2013:1669-75.  Back to cited text no. 3
Ethicon Product Catalog. Sutures/Adhesives/Drains/Hernia Repair. Available from: https://www.woundclosure.ethicon.com/sites/com.wcrc_v2_rest/files/ethicon-catalog.pdf. [Last updated on 2015 Dec 01; Last accessed on 2017 Jul 26].  Back to cited text no. 4


  [Figure 1]


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