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Background: To close elliptical excisions, surgeons commonly use the rule of halves which involves initially closing of the middle portion of the wound, followed by closure of the remaining halves. Understanding the forces required for suturing such wounds can aid excisional surgery planning to decrease complications and improve wound healing., Methods: Following full thickness excision for removal of skin cancers, back wounds with 3:1 ratio of length-to-width were closed using the rule of halves. The force required to bring the wound edges into contact at the middle portion of the wound was measured, followed by the two bisected halves., Findings: The average force to close the center of the wounds averaged 3.7 N and was six times larger than that of the bisected halves. The forces to close the bisected halves were consistently small, and essentially negligible (<0.5 N) for ~50% of the cases., Interpretation: When planning excisional surgery to avoid complications such as tearing the dermis (cheese wiring), the use of special wound closure techniques (high tension and/or pully sutures, skin support or suture retention devices, etc.) should focus on the center suture only when using the rule of halves, as the remaining sutures require very low forces., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objective: Conduct a first in vivo study on the large deformation stress relaxation behavior of the human scalp., Methods: This study was conducted during Mohs micrographic surgery of the scalp of 14 patients aged 59-90 with wounds initially ranging from 9 to 41 mm wide. The initial wound diameter was measured under zero applied force. Then, the force required to close each wound using a single size 1 nylon suture and a SUTUREGARD suture retention device was measured, after which the suture was then locked in the retention device at fixed displacement. At time points of 300 s, 600 s, and 1800 s, the suture retention device was released, and the wound opening was again recorded at zero force, and the force required to close the wound was recorded., Results: The average wound closure force relaxed by 44% and 65% after 300 s and 1800 s, respectively. Average wound width decreased 30% and 42%, after 300 s and 1800 s, respectively, due to creep deformation. Furthermore, all wounds relaxed to be below 15 N of closure force after 600 s, which is considered the maximum clinically acceptable force. A relaxation time of ∼270 s and a threshold force for creep of ∼5 N was found., Significance: Results of this study provide the first quantitative clinical guidance for efficient scalp closure of large wounds by creep deformation and stress relaxation. Furthermore, the methodology developed here can be used as a basis for future in vivo studies of the stress relaxation and creep deformation of human scalp, which in turn can provide data for the development and validation of constitutive models for scalp deformation., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To test the hypothesis that the mechanical strength of wounds closed with a combination of buried dermal absorbable sutures and superficial nonabsorbable nylon sutures will be higher than wounds closed with only superficial nonabsorbable nylon sutures., Methods: Four Yucatan pigs were anesthetized and each received four 4.5cm full thickness incisions on their dorsal surfaces, placed 8cm apart. Half of all incisions were randomly allocated and repaired with 3-0 polyglactin 910 (Vicryl(™)) buried dermal absorbable sutures and superficial 3-0 nylon sutures, using a simple interrupted pattern. The other half received only 3-0 nylon sutures. Two pigs were humanely euthanized at day 10, with specimen harvest for mechanical testing; the other two pigs had superficial nylon sutures removed at day 10, as per current clinical practice, and were humanely euthanized at day 42, with specimen harvest for mechanical testing. Tensile loads were applied perpendicularly to the wounds with a displacement rate of 40mm per minute., Results: Wounds at day 42 were >9 times stronger than wounds at day 10 (p<0.0001). There was no difference in average wound strength at either day 10 or day 42 between wounds with and without buried dermal absorbable sutures., Significance: Buried dermal absorbable sutures failed to provide additional wound support at either 10 or 42 days. This result may have immediate implications for clinicians who perform cutaneous surgery and keep superficial sutures in for at least 10 days. Future research will be directed to shorter time studies, other buried dermal absorbable suture materials, and alternatives to buried dermal absorbable sutures., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)