Lacrimal Dilator-Facilitated vs Standard Sub-Tenon's Block

Lacrimal Dilator-Facilitated Incisionless Vs. Standard Sub-Tenon's Block: A Randomized, Prospective and Non-inferiority Comparative Study

Standard sub-Tenon's block involves incision (dissection) of conjunctiva and Tenon's capsule with the help of blunt scissors and forceps, insertion of a blunt sub-Tenon's cannula under the Tenon's capsule and injection of local anaesthetic agent. This block is frequently associated with minor complications such as chemosis and subconjunctival haemorrhage. Different variations of incisionless sub-Tenon's block including the use of lacrimal dilator have been described to reduce minor complications and facilitate insertion of blunt cannula. Lacrimal dilator creates a small aperture in the conjunctiva and Tenon's capsule thus avoids incision. After ethics approval, patients undergoing elective cataract surgery were enrolled to receive sub-Tenon's block performed without incision with a lacrimal dilator (Group LD) or with incision using Wescott scissors and blunt forceps (Group WS). All patients received 3 mL 2% lidocaine without any adjuvant. No sedation was administered. Demographic of the patients, duration of the procedure, analgesia (pain), akinesia, duration of the procedure intraoperative chemosis, subconjunctival haemorrhage on the first postoperative day. We aimed to compare lacrimal dilator-facilitated and standard sub-Tenon's block effectiveness and incidence of chemosis and subconjunctival haemorrhage.

Study Overview

• Status: Completed
• Conditions: to Compare Lacrimal Dilator-facilitated Incisionless and Standard STB With Wescott Scissors
• Intervention / Treatment: Device: sub-Tenon's block with a lacrimal dilator group or a Wescott scissors

Detailed Description

The patients were randomly allocated to receive STB performed with a lacrimal dilator (Group LD) and with a Wescott scissors (Group WS). Randomization was ensured by sealed envelopes prepared according to a computer-generated table and the envelopes were opened by the operator just before the sub-Tenon's block.

Study protocol Local anaesthetic eye drops were installed into the conjunctiva, followed by iodine 5% aqueous drops to the conjunctival sac for 3 minutes.19 An eye lid speculum was inserted.

In group LD, the conjunctiva and Tenon's capsule were lifted together tightly with a blunt forceps like a tent in the inferonasal quadrant and a punctal dilatator was placed tangential to the globe creating a round and small hole at 5 mm posterior to limbus. The block was performed using smooth rounded tip, 19 G, 1 inch sub-Tenon's cannula .

In Group WS, after lifting the conjunctiva and Tenon's capsule together with a blunt forceps, incision was performed with a blunt tip Westcott scissors in the inferonasal conjunctival at 5 mm posterior to limbus to expose sub-Tenon's space. The block was performed with the above sub-Tenon's cannula.

All patients received lidocaine 2%, 3 mL without any adjuvant. No sedative was administered. All the blocks and surgeries were performed by the same investigator, but block evaluations were made by another investigator who was blinded to the technique used. All patients were discharged on the day of surgery.

The parameters recorded included demographic of the patients, duration of the procedure, analgesia (pain), akinesia, duration of the procedure intraoperative chemosis, subconjunctival haemorrhage on the first postoperative day. Analgesia was evaluated using a numeric rating scale for pain (0-10; 0 - no pain, 10 - the worst imaginable pain) immediately after the operation. Akinesia (ocular movements) were checked according to 4-primary gazes 10 minutes after STB. Chemosis and conjunctival haemorrhage (1st postoperative day) were assessed according to the number of quadrant or quadrants affected (superior nasal, superior temporal, inferior nasal, inferior temporal) using a 5-point scale (0-4; 0 - no for chemosis and haemorrhage, 4 for chemosis or haemorrhage in all 4 quadrants).

• Study Type: Interventional
• Enrollment (Actual): 64
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey
  • Adana, Turkey, 01250
    • Baskent University, Adana Research and Training Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 88 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

patients undergoing cataract surgery by phacoemulsification and intraocular lens implantation

Exclusion Criteria:

allergy to lidocaine, history of previous retinal and strabismus surgery, bleeding disorders and oral anticoagulant use, presence of glaucoma or high IOP, thick pterygia, any pathological condition that conjunctiva and Tenon's capsule cannot be lifted away from the sclera

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: a lacrimal dilator group (Group LD); The patients allocated to receive STB performed with a lacrimal dilator	Device: sub-Tenon's block with a lacrimal dilator group or a Wescott scissors; Local anaesthetic eye drops were installed into the conjunctiva, followed by iodine 5% aqueous drops to the conjunctival sac for 3 minutes.19 An eye lid speculum was inserted. In group LD, the conjunctiva and Tenon's capsule were lifted together tightly with a blunt forceps like a tent in the inferonasal quadrant and a punctal dilatator (Castroviejo Lacrimal Dilatator, Katena Products, Inc, Denville, NJ, USA) was placed tangential to the globe creating a round and small hole at 5 mm posterior to limbus (Fig.1). The block was performed using smooth rounded tip, 19 G, 1 inch sub-Tenon's cannula (Visitec, Beaver-Visitec International Ltd, Warwickshire, UK). In Group WS, after lifting the conjunctiva and Tenon's capsule together with a blunt forceps, incision was performed with a blunt tip Westcott scissors in the inferonasal conjunctival at 5 mm posterior to limbus to expose sub-Tenon's space.
Active Comparator: a Wescott scissors (Group WS); The patients allocated to receive STB performed with a Wescott scissors	Device: sub-Tenon's block with a lacrimal dilator group or a Wescott scissors; Local anaesthetic eye drops were installed into the conjunctiva, followed by iodine 5% aqueous drops to the conjunctival sac for 3 minutes.19 An eye lid speculum was inserted. In group LD, the conjunctiva and Tenon's capsule were lifted together tightly with a blunt forceps like a tent in the inferonasal quadrant and a punctal dilatator (Castroviejo Lacrimal Dilatator, Katena Products, Inc, Denville, NJ, USA) was placed tangential to the globe creating a round and small hole at 5 mm posterior to limbus (Fig.1). The block was performed using smooth rounded tip, 19 G, 1 inch sub-Tenon's cannula (Visitec, Beaver-Visitec International Ltd, Warwickshire, UK). In Group WS, after lifting the conjunctiva and Tenon's capsule together with a blunt forceps, incision was performed with a blunt tip Westcott scissors in the inferonasal conjunctival at 5 mm posterior to limbus to expose sub-Tenon's space.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
chemosis	swelling of the conjunctiva	10 minutes after intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
subconjunctival haemorrhage	haemorrhage due to tearing or severing of blood vessels during dissection and injection	on the postoperative first day

Collaborators and Investigators

• Sponsor: Baskent University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2019
• Primary Completion (Actual): September 30, 2019
• Study Completion (Actual): October 15, 2019

Study Registration Dates

• First Submitted: April 10, 2020
• First Submitted That Met QC Criteria: April 10, 2020
• First Posted (Actual): April 14, 2020

Study Record Updates

• Last Update Posted (Actual): April 14, 2020
• Last Update Submitted That Met QC Criteria: April 10, 2020
• Last Verified: April 1, 2020

More Information

Terms related to this study

• Keywords: sub-Tenon's block, lacrimal dilator, Wescott scissors, chemosis, subconjunctival haemorrhage
• Other Study ID Numbers: KA19/165

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: This will be decided according to the content of the request

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No