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Anaesthesia for Ophthalmic Surgery: How "Retro" is the Peribulbar Block?

This study has been completed.
Information provided by:
Sunnybrook Health Sciences Centre Identifier:
First received: December 8, 2010
Last updated: June 8, 2011
Last verified: December 2010
Ophthalmic surgery on the posterior section of the eye can either be performed under general anaesthesia or under local aneasthesia. The local anaesthesia is performed by injecting local anaesthetics behind the eye. There are two techniques: Either the needle is placed into the muscle cone formed by the four recti muscles - this is called intraconal or retrobulbar block, or the needle is placed outside of the muscle cone - this would be called extraconal or peribulbar. In our hospital the investigators usually perform the peribulbar block since it is easier to perform and has a smaller risk to injure the eye. The investigators however realize that the parabulbar block is sometimes very efficient and sometimes not, thus requiring a second or third injection. Now investigators are able to visualize where the local anaesthetics spreads with the help of ultrasound imaging. The aim of the study is to observe and to describe the incidence of intraconal spread of local anaesthetics when a peribulbar block is performed.

Condition Intervention
Ophthalmic Surgery
Parabulbar Block
Procedure: Ultrasound detection of local anesthetics spread

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Anaesthesia for Ophthalmic Surgery: How "Retro" is the Peribulbar Block?

Resource links provided by NLM:

Further study details as provided by Sunnybrook Health Sciences Centre:

Primary Outcome Measures:
  • Incidence of detectable retrobulbar spread of local anaesthetics during peribulbar injection. [ Time Frame: At start (During peribulbar injection) ]
    The outcome measure is the description of the spread of local anesthetics during the injection of the drug via the parabulbar needle.

Secondary Outcome Measures:
  • Assessment of block quality [ Time Frame: 20 Minutes after block ]
    Assessment of the block quality by ophthalmic surgeon just before surgery starts and at least 20 minutes after the block: complete akinesia and anaesthesia or partial akinesia/anaesthesia.

Estimated Enrollment: 100
Study Start Date: January 2011
Study Completion Date: June 2011
Primary Completion Date: June 2011 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
Ophthalmic surgery patients
Patients (men and women) of at least 18 years of age undergoing an ophthalmic procedure on the posterior section of the eye under local anaesthesia, i.e. with a peribulbar block. Inclusion and exclusion criteria for the study are the same as for the peribulbar anaesthesia.
Procedure: Ultrasound detection of local anesthetics spread
During the parabulbar injection the ultrasound operator experienced in ultrasound guided retrobulbar block will assess whether there is spread of local anaesthetic in the central cone just behind the sclera (yes or no). The anaesthesist performing the block will be blinded to the ultrasound visualized spread of local anaesthetic.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
100 consecutive patients (men and women) of at least 18 years of age undergoing an ophthalmic procedure on the posterior section of the eye under local anaesthesia, i.e. with a peribulbar block.

Inclusion Criteria:

-informed consent

Exclusion Criteria:

  • coagulation disorder
  • INR over 1.5 and/or a platelet count less than 75 X 109/L,
  • pathological myopia,
  • inability of the patient to lie down for the operation for more than 2 hours
  • lack of informed consent.
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Please refer to this study by its identifier: NCT01258959

Canada, Ontario
Sunnybrook Health Science Centres
Toronto, Ontario, Canada, M4N 3M5
Sponsors and Collaborators
Sunnybrook Health Sciences Centre
  More Information

Responsible Party: Paul McHardy, Sunnybrook Health Science Centre Identifier: NCT01258959     History of Changes
Other Study ID Numbers: Retro-Parabulbar
Study First Received: December 8, 2010
Last Updated: June 8, 2011

Keywords provided by Sunnybrook Health Sciences Centre:
Ultrasound, retrobulbar, parabulbar, ophthalmic surgery.

Additional relevant MeSH terms:
Anesthetics, Local
Central Nervous System Depressants
Physiological Effects of Drugs
Sensory System Agents
Peripheral Nervous System Agents processed this record on April 28, 2017