Two versus one injection for eye block

ISRCTN	ISRCTN73431052
DOI	https://doi.org/10.1186/ISRCTN73431052
Protocol serial number	N/A
Sponsor	Cork University Hospital (Ireland)
Funder	Investigator initiated study - no extra funding required as Sub-Tenon's block is routinely used

Submission date: 30/09/2008
Registration date: 31/10/2008
Last edited: 30/12/2020

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Eye Diseases

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Not provided at time of registration

Contact information

Dr Jawad Mustafa
Scientific

South Infirmary Hospital
Cork
-
Ireland

Study information

Primary study design	Interventional
Study design	Single blinded, prospective, randomised controlled trial
Secondary study design	Randomised controlled trial
Scientific title	Efficacy of Sub-Tenon's block using an equal volume of local anaesthestic administered either as a single or as divided doses
Study acronym	SubTenon
Study objectives	Our hypothesis was that a divided injection into the Sub-Tenons space would achieve greater, more consistent and more rapid motor blockade then a single injection using equal volumes and mixtures of local anaesthetic solution.
Ethics approval(s)	Ethics Committee of Cork University Hospital, approval received in 2003.
Health condition(s) or problem(s) studied	Cataract surgery
Intervention	On arrival in the induction room, intravenous excess was secured and monitoring with non-invasive blood pressure (NIBP), electrocardiogram (ECG), and pulse oximetry (Datex AS3) established. Topical anaesthesia was established by instillation of benoximate eye drops and after 2 minutes an eye speculum inserted. With the eye in neutral position, the conjunctiva was lifted in the infranasal quadrant with the help of Moorsfields forceps and using Westcott's scissors a small incision was made in the conjunctiva. A 19 gauge Stephens's cannula was carefully placed subconjuctivally into the Sub-Tenon's space. In group 1, 5 ml of local anaesthetic solution comprising 2.5 ml of 2% lignocaine with 1:200,000 adrenaline, 15 IU/ml of hyaluronidase and 2.5 ml of 0.5% bupivacaine was injected over thirty seconds. After the injection orbital pressure was applied for two minutes. In group 2, 3 ml of the same anaesthetic solution described above was injected and cannula withdrawn followed by application of orbital pressure for 2 minutes. A further 2 ml of the same anaesthetic solution was injected through the same conjunctival incision with approx three minutes between the two injections. Intraocular pressures were measured by a hand held tonometer (knowa) prior to injection and six minutes after the first (or sole) injection and compared with pre-injection value.
Intervention type	Drug
Phase	Not Specified
Drug / device / biological / vaccine name(s)	Benoximate, lignocaine, adrenaline, hyaluronidase, bupivacaine
Primary outcome measure(s)	Measurement of movement was performed by the operating surgeon who was unaware of the anaesthetic technique used in all four quadrants (inferior, superior, redial, lateral) using a vernier calliper and scored according to movement: 0 = no movement 1 = movement of less than 2 mm 2 = movement of more than 2 mm Motor function was evaluated at two time intervals, 3 and 6 minutes after the initial injection. Overall movement score was obtained by combining the scores of these four muscles. This score ranged from 0 (no movement) to 8 (complete movement) and was categorised into two groups, akinesia (score 0 - 4) and no akinesia (score 5 - 8). All measured during the surgery.
Key secondary outcome measure(s)	Chemosis and subconjuctival haemorrhage were also assessed by surgeons before starting surgery as mild, moderate or severe. All measured during the surgery.
Completion date	31/12/2003

Eligibility

Participant type(s)	Patient
Age group	Other
Sex	All
Target sample size at registration	60
Total final enrolment	60
Key inclusion criteria	1. American Society of Anaesthesiologists (ASA) I - III patients undergoing cataract surgery 2. No age range, both male and female patients
Key exclusion criteria	1. Allergy to any of the drugs administered 2. Impaired mental status 3. Uncontrolled glaucoma 4. Clotting abnormalities 5. Recent surgical procedure on the same eye
Date of first enrolment	01/06/2003
Date of final enrolment	31/12/2003

Locations

Countries of recruitment

Ireland

Study participating centre

South Infirmary Hospital

Cork
-
Ireland

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	26/03/2009	30/12/2020	Yes	No

Editorial Notes

30/12/2020: The following changes have been made:
1. Publication reference added.
2. The final enrolment number has been added from the reference.