title: Autologous platelet-poor plasma gel for injection laryngoplasty.
abstract: OBJECTIVE
  To overcome the potential disadvantages of the use of foreign materials and autologous fat or collagen, we introduce here an autologous plasma gel for injection laryngoplasty. The purpose of this study was to present a new injection material, a plasma gel, and to discuss its clinical effectiveness.
  
  
  METHODS
  From 2 mL of blood, the platelet poor serum layer was collected and heated at 100°C for 12 min to form a plasma gel. The plasma gel was then injected into a targeted site; the safety and efficacy thereof were evaluated in 30 rats. We also conducted a phase I/II clinical study of plasma gel injection laryngoplasty in 11 unilateral vocal fold paralysis patients.
  
  
  RESULTS
  The plasma gel was semi-solid and an easily injectable material. Of note, plasma gel maintains the same consistency for up to 1 year in a sealed bottle. However, exposure to room air causes the plasma gel to disappear within 1 month. In our animal study, the autologous plasma gel remained in situ for 6 months in animals with minimal inflammation. Clinical study showed that vocal cord palsy was well compensated for with the plasma gel in all patients at two months after injection with no significant complications. Jitter, shimmer, maximum, maximum phonation time (MPT) and mean voice handicap index (VHI) also improved significantly after plasma gel injection. However, because the injected plasma gel was gradually absorbed, 6 patients needed another injection, while the gel remained in place in 2 patients.
  
  
  CONCLUSIONS
  Injection laryngoplasty with autologous plasma gel may be a useful and safe treatment option for temporary vocal cord palsy.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Korea. hansin.jeong@gmail.com.
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Woo
authors.forename: Jin Pyeong
authors.initials: JP
authors.lastname: Kim
authors.forename: Jung Je
authors.initials: JJ
authors.lastname: Park
authors.forename: Phil-Sang
authors.initials: PS
authors.lastname: Chung
authors.forename: Sang-Hyuk
authors.initials: SH
authors.lastname: Lee
authors.forename: Han-Sin
authors.initials: HS
authors.lastname: Jeong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001792:Blood Platelets; D005260:Female; D006801:Humans; D058753:Laryngoplasty / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000502:physiology*; D051381:Rats
keywords: Plasma gel; acoustical analysis; injection; laryngoplasty; vocal cord palsy