title: Effect of cog threads under rat skin.
abstract: BACKGROUND
  The aging face loses the tensile strength of structural integrity. Cog threads have been used recently to tighten lax skin and soft tissue.
  
  
  OBJECTIVE
  A comparative study of the effects of cog, monofilament, and multifilament threads under rat skin.
  
  
  METHODS
  Each cog, monofilament, and multifilament thread was inserted under the facial skin of a cadaver and the panniculus carnosus of rat dorsal skin. The maximum holding strength (MHS) of the thread and the tearing strength of the skin around the thread were measured with a tensiometer. The thickness of the capsule around the thread and the myofibroblasts was observed histologically.
  
  
  RESULTS
  In the cadaver, the MHS of the cog thread was 190.7 +/- 65.6 g. It was greater than that of the monofilament (22.4 +/- 7.7 g) or multifilament (40.4 +/- 19.7 g) thread. In the rat, the MHS of the cog thread was 95.1 +/- 18.8 g. It was greater than that of the monofilament (4.3 +/- 1.3 g) or multifilament (10.9 +/- 2.1 g) thread in the second week. The thickness of the capsule around the cog thread was 93.0 +/- 3.2 microm. It was thicker than the monofilament thread's capsule, 39.2 +/- 12.1 microm, in the fourth week. The number of myofibroblasts presented significantly more in the cog (96.0 +/- 72.4) than in the monofilament thread (4.3 +/- 4.4). The rumpled in-between skin suspended by each of the three different threads returned to its original state in 2 weeks.
  
  
  CONCLUSIONS
  The cog thread placed under the rat skin immediately pulled the skin and subcutaneous tissue. The myofibroblasts around the thread played a role in fibrous tissue contracture 4 weeks postinsertion of the thread. These findings could be the basis for clinical application.
authors.affiliation: Department of Plastic Surgery, Inha University, Incheon, Korea.
authors.forename: Hyo Jook
authors.initials: HJ
authors.lastname: Jang
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Lee
authors.forename: Kun
authors.initials: K
authors.lastname: Hwang
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Dae Joong
authors.initials: DJ
authors.lastname: Kim
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D002102:Cadaver; D003286:Contracture; D062109:Dermatologic Surgical Procedures; D005347:Fibroblasts; D005549:Foreign-Body Reaction; D006801:Humans; D023421:Models, Animal; D011098:Polyglactin 910 / Q000494:pharmacology; D011126:Polypropylenes / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015361:Rhytidoplasty / Q000295:instrumentation; D015595:Skin Aging; D040521:Subcutaneous Tissue / Q000601:surgery; D013537:Sutures; D013718:Tensile Strength; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D011126:Polypropylenes; D011098:Polyglactin 910