title: A comparative study between 25 x 0.70 mm and 20 x 0.55 mm needles for retrobulbar block with small volume of anesthetic for the treatment of cataracts by phacoemulsification.
abstract: OBJECTIVE
  The objective of this study was to compare the quality and safety of retrobulbar block for the treatment of cataracts by phacoemulsification using needles of different sizes: 27 x 0.70 mm and 20 x 0.55 mm.
  
  
  METHODS
  Candidates for ophthalmic block for the treatment of cataracts by phacoemulsification were selected prospectively. After sedation and standardized monitoring, a retrobulbar block with 4 mL of 1% ropivacaine containing hyaluronidase was performed with a single inferolateral puncture. In Group I (GI), the 25 x 0.70 mm needle was used, while in Group II (GII) a 20 x 0.55 mm needle was used. All patients had a CT scan at the time of the blockade and five minutes after the administration of the anesthetic solution with radiologic contrast. Ocular mobility was assessed after three, five, and ten minutes. The incidence of complications in both groups and the satisfaction of patients and surgeons were compared by applying a standardized questionnaire.
  
  
  RESULTS
  Fifty-four adult patients were evaluated (27 per group). Patients did not complain of intraoperative pain or perception of light. The anesthetic procedure was considered very good (VG) or excellent (E) in 96.3% of the cases in both groups. All patients were subjected to the same assessment. The need of block repetition between both groups did not differ (p = 1.0). Patients in GI showed decreased ocular mobility at 3 minutes (p = 0.03). The intraconal retrobulbar placement of the needle was observed on both groups. Anesthetic dispersion at 5 minutes was similar in the two groups.
  
  
  CONCLUSIONS
  Retrobulbar block with a single inferolateral puncture with a 20 x 0.55 mm needle, using low doses of anesthetics, is an effective and safe option for the treatment of cataracts by phacoemulsification.
authors.affiliation: Centro de Referência em Oftalmologia da Universidade Federal de Goiás (CEROF-UFG), do Departamento de Patologia e Imaginologia e CET/SBA do Hospital das Clínicas da Universidade Federal de Goiás (HC-UFG), Goiânia, GO. haroldo62@hotmail.com
authors.forename: Haroldo Maciel
authors.initials: HM
authors.lastname: Carneiro
authors.forename: Kim Irsen Santos
authors.initials: KI
authors.lastname: Teixeira
authors.forename: Marcos Pereira
authors.initials: MP
authors.lastname: de Avila
authors.forename: Onofre
authors.initials: O
authors.lastname: Alves Neto
authors.forename: Rosanna Zacharias
authors.initials: RZ
authors.lastname: Hannouche
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Magacho
mesh_terms: D000368:Aged; D002387:Cataract Extraction; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation*; D009900:Optic Nerve; D018918:Phacoemulsification; D011446:Prospective Studies; D016037:Single-Blind Method