title: Pressure generated by syringes: implications for hydrodissection and injection of dense connective tissue lesions.
abstract: OBJECTIVE
  Hydrodissection and high-pressure injection are important for the treatment of dense connective tissue lesions including rheumatoid nodules, Dupuytren's contracture, and trigger finger. The present study determined the optimal syringes for high-pressure injection of dense connective tissue lesions.
  
  
  METHODS
  Different sizes (1, 3, 5, 10, 20, and 60 mL) of a mechanical syringe (reciprocating procedure device) with a luer-lock fitting were studied. Twenty operators generated maximum pressure with each mechanical syringe size, and pressure was measured in pounds per square inch (psi). Subsequently, 223 dense connective tissue lesions were injected with different sizes of syringes (1, 3, or 10 mL). Outcomes included (i) successful intralesional injection and (ii) clinical response at 2 weeks.
  
  
  RESULTS
  Smaller syringes generated significantly more injection pressure than did larger syringes: 1 mL (363 ± 197 psi), 3 mL (177 ± 96 psi), 5 mL (73 ± 40 psi), 10 mL (53 ± 29 psi), 20 mL (32 ± 18 psi), and 60 mL (19 ± 12 psi). Similarly, smaller syringes were superior to larger syringes for intralesional injection success: 10 mL: 34% (15/44) vs. 1 mL: 100% (70/70) (p < 0.001) and 3 mL: 91% (99/109) (p < 0.001).
  
  
  CONCLUSIONS
  Smaller syringes (≤ 3 mL) are superior to larger syringes (≥ 5 mL) for successful hydrodissection and high-pressure intralesional injection of dense connective tissue lesions.
authors.affiliation: Lonestar Montgomery College, The Woodlands, TX, USA.
authors.forename: W A P
authors.initials: WA
authors.lastname: Hayward
authors.forename: L J
authors.initials: LJ
authors.lastname: Haseler
authors.forename: L G
authors.initials: LG
authors.lastname: Kettwich
authors.forename: A A
authors.initials: AA
authors.lastname: Michael
authors.forename: W l
authors.initials: Wl
authors.lastname: Sibbitt
authors.forename: A D
authors.initials: AD
authors.lastname: Bankhurst
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D003238:Connective Tissue / Q000473:pathology*; D004387:Dupuytren Contracture / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007267:Injections; D010147:Pain Measurement; D011312:Pressure; D012218:Rheumatoid Nodule / Q000473:pathology / Q000628:therapy*; D013594:Syringes; D052582:Trigger Finger Disorder / Q000473:pathology / Q000628:therapy*
chemical_list: D000305:Adrenal Cortex Hormones