title: Shunt implantations and peritoneal catheters: Do not cut beyond 20 cm.
abstract: BACKGROUND
  Ventriculoperitoneal shunts are supplied with long peritoneal catheters, most commonly between 80 and 120 cm long. ISO/DIS 7197/2006([15]) shunt manufacturing procedures include peritoneal catheter as an integrate of the total resistance. Cutting pieces of peritoneal catheters upon shunt implantation or revision is a common procedure.
  
  
  METHODS
  We evaluated five shunts assembled with different total pressure resistances and variable peritoneal catheter lengths in order to clarify the changes that occurred in the hydrodynamic profile when peritoneal catheters were cut upon shunt implantation or shunt revision.
  
  
  RESULTS
  Originally, all shunts performed within the operational range. Shunt 1 performed in a lower pressure range at 200 mm cut off peritoneal catheter and as a low-pressure shunt with -300 mm cut off. Shunt 2 was manufactured to run at the higher border pressure range, and it went out of specification with a 300 mm cut off. Shunt 3 was manufactured to run close to the lower border pressure range, and at 100 mm cutoff, it was already borderline in a lower resistive category. Other shunts also responded similarly.
  
  
  CONCLUSIONS
  The limit to maintain a shunt in its original pressure settings was 20 cm peritoneal catheter cutting length. By cutting longer pieces of peritoneal catheter, one would submit patients to a less-resistive regimen than intended and his reasoning will be compromised. The pediatric population is more prone to suffer from the consequences of cutting catheters. Shunt manufacturers should consider adopting peritoneal catheters according to the age (height) of the patient.
authors.affiliation: Department of Neurosurgery, FUNFARME, São José do Rio Preto, SP; Founder and Owner for Ventura Biomedica Ltda, Brazil.
authors.forename: Angelo Luiz
authors.initials: AL
authors.lastname: Maset
authors.affiliation: São Paulo Federal University, São Paulo, SP, Brazil.
authors.forename: Ltalo Capraro
authors.initials: LC
authors.lastname: Suriano
authors.affiliation: Head of Department Neurosurgery, Hospital Municipal Miguel Couto, Rio de Janeiro, RJ, Brazil.
authors.forename: Ruy
authors.initials: R
authors.lastname: Monteiro
authors.affiliation: Department of Engineering, Ventura Biomédica Ltda, São José do Rio Preto, Brazil.
authors.forename: José Ricardo Camilo
authors.initials: JR
authors.lastname: Pinto
authors.affiliation: Department of Engineering, Ventura Biomédica Ltda, São José do Rio Preto, Brazil.
authors.forename: José Ricardo
authors.initials: JR
authors.lastname: de Andrade
authors.affiliation: Department of Engineering, Ventura Biomédica Ltda, São José do Rio Preto, Brazil.
authors.forename: Bruna Monieli
authors.initials: BM
authors.lastname: Mancini
authors.affiliation: Department of Neurosurgery, São José do Rio Preto, Brazil.
authors.forename: Sérgio Luiz
authors.initials: SL
authors.lastname: Ramin
authors.affiliation: Chairman, Department of Neurosurgery, FUNFARME, São José do Rio Preto, Brazil.
authors.forename: Dionei Freitas
authors.initials: DF
authors.lastname: Moraes
authors.affiliation: Professor and Chairman, São Paulo Federal University, São Paulo, SP, Brazil.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Cavalheiro
keywords: Hydrocephalus; shunt hydrodynamics; shunt overdrainage