title: The Influence of Trocar Fenestration and Volume on Connective Tissue Progenitor Cells (Stem Cells) in Arthroscopic Bone Marrow Aspiration From the Proximal Humerus.
abstract: OBJECTIVE
  To evaluate the number of connective tissue progenitor cells (CTPs) and nucleated cells obtained during bone marrow aspiration (BMA) from the proximal humerus using either a fenestrated or a nonfenestrated trocar and determine differences in varying amounts of aspiration volume. The first hypothesis was that the number of CTPs extracted with the fenestrated trocar would be greater due to its potential to extract more cells through its fenestrations. The second hypothesis was that using consecutive aspirations with either trocar would provide a consistent number of CTPs and nucleated cells throughout the aspiration with no significant decrease of cells at the end.
  
  
  METHODS
  Patients were eligible for inclusion if they underwent primary or revision arthroscopic rotator cuff surgery, were between 18 and 75 years of age, and signed the informed consent. Between January 2011 and September 2013, 24 patients underwent BMA from the proximal humerus during arthroscopic surgery. They were grouped according to which of 3 different trocars were used for aspiration: (1) nonfenestrated, (2) fenestrated trocar A, and (3) fenestrated trocar H. Four consecutive 12 mL double syringes were used for each aspiration: 1 (0-12 mL), 2 (12-24 mL), 3 (24-36 mL), and 4 (36-48 mL). One milliliter was removed from each syringe (nonconcentrated BMA). The remainder of the BMA was then spun using a centrifuge. BMA and concentrated BMA were brought to the laboratory, counted for nucleated cells (million cells/mL BMA) and cultured for 7 days to obtain colony-forming units (CTPs/million cells).
  
  
  RESULTS
  No significant differences were observed in tubes 1 to 4 in the number of nucleated cells in the nonconcentrated and concentrated BMA using the nonfenestrated trocar compared with the fenestrated trocars A and H (all P > .05), except for concentrated BMA tube 3 (P = .014) and tube 4 (P = .003). Nonconcentrated and concentrated BMA from tubes 1 to 4 had a significantly higher CTP prevalence using the nonfenestrated trocar compared with the fenestrated trocars A and H (all P < .05). Most of the times the first tube of each aspiration showed a significantly greater amount of cells and a greater CTP prevalence compared with tubes 2, 3, and 4.
  
  
  CONCLUSIONS
  Aspiration from the proximal humerus with the nonfenestrated trocar during BMA was associated with higher prevalence of CTPs, suggesting that more CTPs can be obtained using a nonfenestrated trocar. Furthermore, CTPs can be obtained through all consecutive aspirations with a greater amount in the first tubes.
  
  
  METHODS
  Level II, prospective comparative study.
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.; Department of Orthopaedic Sports Medicine, Technical University of Munich, Munich, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Voss
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: McCarthy
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Hardeep
authors.initials: H
authors.lastname: Singh
authors.affiliation: Department of Orthopaedic Sports Medicine, Technical University of Munich, Munich, Germany.
authors.forename: Knut
authors.initials: K
authors.lastname: Beitzel
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Jessica
authors.initials: J
authors.lastname: DiVenere
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Cote
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Hoberman
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.
authors.forename: Michael
authors.initials: M
authors.lastname: Nowak
authors.affiliation: Department of Orthopaedic Sports Medicine, Technical University of Munich, Munich, Germany.
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Imhoff
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut, Farmington, Connecticut, U.S.A.. Electronic address: mazzocca@uchc.edu.
authors.forename: Augustus D
authors.initials: AD
authors.lastname: Mazzocca
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001182:Arthroscopy / Q000295:instrumentation* / Q000379:methods; D003239:Connective Tissue Cells / Q000166:cytology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006811:Humerus / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D010012:Osteogenesis; D011446:Prospective Studies; D017006:Rotator Cuff / Q000601:surgery*; D013234:Stem Cells / Q000166:cytology; D013396:Suction; D013525:Surgical Instruments; D055815:Young Adult