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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Post Operative Pain Management Following Pterygium Surgery
Scientific title
Efficacy of sub-tenons bupivacaine for post-operative pain management following pterygium surgery.
Secondary ID [1] 289756 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pain severity following pterygium excision (with free conjunctival graft and glue) 299610 0
Condition category
Condition code
Eye 299576 299576 0 0
Diseases / disorders of the eye
Anaesthesiology 299722 299722 0 0
Pain management

Study type
Description of intervention(s) / exposure
Single dose Bupivacaine (0.5%) 2.5mls into the subtenon space in an eye undergoing pterygium excision. The anaesthetic is drawn up by the scrub nurse and injected via a subtenons cannula by the surgeon after the pterygium has been removed, but before the graft is secured to the sclera.
Intervention code [1] 295405 0
Treatment: Drugs
Comparator / control treatment
Basic salt solution (2.5mls) injected into the subtenons space by the surgeon at the time of pterygium surgery (placebo arm)
Control group

Primary outcome [1] 299053 0
All patients will be asked to complete a questionaire for days 3 post surgery. Ms Hughes will contact patients daily for four days and document the following variables (pain, irritation, light sensitivity) as well as total pain relief consumed. . .

Pain score graded on a continous scale from 1-10.
0 = no pain
10 = severe pain

Patients always receive a drop of topical anaesthetic (tetracaine 1%) immediately prior to surgery. This drop causes a stinging senation/pain in the eye.. As pain is a subjective experience, patients will be asked to quantify their pain following instillation of topical anaesthetic. This information will allow adjustments to be carried out for individual pain tolerance when interpreting pain scores.
Timepoint [1] 299053 0
Daily assessment of pain for three days postoperatively.
Secondary outcome [1] 326016 0
Irritation graded as none/mild/moderate/severe
Timepoint [1] 326016 0
Irritation severity graded daily for three days postoperatively.
Secondary outcome [2] 326017 0
Light sensitvity as graded as none/mild/moderate/severe
Timepoint [2] 326017 0
Light sensitivity severity grade daily for three days postoperatively.
Secondary outcome [3] 326018 0
Ms Hughes will contact patients daily for four days to assess the total amount and type of pain relief consumed each day. The questionnaire also asks patients to self report the type (and time) of pain relief consumed each day based on a list of options ie paracetamol 1g QID/prn, ibuprofen 400mg TDS/prn (with food) and tramadol 50mg QID/prn.
Timepoint [3] 326018 0
Total pain relief consumed daily for the first three postoperative days.

Key inclusion criteria
Age >18
Primary nasal pterygium excision with conjunctival graft and glue
Understands the risks/benefits of the study
Able to give consent
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Recurrent pterygium
Multiple pterygiums present in the operated eye
Surgery performed under general anaesthesia
Suture required during surgery

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Double blinded RCT

Central randomisation by computer (Office Excel) by an independent party. Allocation plan will be secured in an opaque envelope and opened by the nurses assisting the surgeon. The nurse who will prepare the subtenons syringe depending on which arm the patient is allocated to. The surgeon will administer the intervention.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (Office Excel)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis
Other studies have recorded pain scores of 5/10 on the day of surgery and scores of 3/10 for the subsequent 3 days. In order to observe a reduction in the amount of pain from 5 to 3 (standard deviation 2) on the day of surgery with an alpha error of 0.05 and study power of 0.8 (Beta = 0.2), we calculated that 16 patients would be required in each arm.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 8049 0
New Zealand
State/province [1] 8049 0

Funding & Sponsors
Funding source category [1] 294189 0
Name [1] 294189 0
Waikato Hospital
Address [1] 294189 0
Selwyn Street and Pembroke Street, Hamilton 3204

Country [1] 294189 0
New Zealand
Funding source category [2] 294321 0
Name [2] 294321 0
Palmerston North Public Hospital
Address [2] 294321 0
50 Ruahine St, Roslyn, Palmerston North 4442
Country [2] 294321 0
New Zealand
Primary sponsor type
Waikato Hospital
Selwyn Street and Pembroke Street, Hamilton 3204
New Zealand
Secondary sponsor category [1] 293014 0
Name [1] 293014 0
Palmerston North Hospital
Address [1] 293014 0
50 Ruahine St, Roslyn, Palmerston North 4442
Country [1] 293014 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 295592 0
Ethics committee address [1] 295592 0
Ethics committee country [1] 295592 0
New Zealand
Date submitted for ethics approval [1] 295592 0
Approval date [1] 295592 0
Ethics approval number [1] 295592 0

Brief summary
A pterygium is a noncancerous growth on the front surface of the eye (cornea) which can cause redness, irritation and distortion in vision. The aim of surgery is to restore the normal curvature of front of the eye by peeling the pterygium off the cornea. This is done under local anaesthesia, in the form of eye drops and an anaesthetic injection into the pterygium. The medicine commonly used for injection are lidocaine or bupivacaine, the latter has a slightly greater duration of effect. The anaesthetic wears off shortly after the surgery after which the eye becomes uncomfortable, especially for the first 24 hours following surgery. This is because the cornea is more sensitive than any other structure in the body and the takes 3-7 days to heal. Unfortunately most conventional oral pain relief medicines do not effectively reduce eye pain.

There are other ways of numbing the eye including a subtenons block where an anaesthetic medicine (mentioned above) is injected around the eye at the time of surgery. This is easily done once the pterygium has been removed as the subtenons space becomes accessible. This type of anaesthetic not only numbs the eye but temporally impairs ocular motility, causes drooping of the upper lid and can impair vision for up to 8 hours. The latter is not an issue as a pad covers the eye for the first 24hrs after surgery. This type of regional anaesthesia is very safe and is routinely performed for patients undergoing intraocular procedures such as cataract surgery. Anecdotal evidence suggests this mode of anaesthesia may provide better postoperative pain control for patients undergoing pterygium surgery. The aim of our study is to determine wheather a subtenons block given at the time of surgery, in addition to topical and injected anaesthesia, provides better short term post-operative pain control for patients undergoing pterygium surgery compared to traditional methods of anaesthesia.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 1929 1929 0 0

Principal investigator
Name 67694 0
Dr Riyaz Bhikoo
Address 67694 0
Palmerston North Hospital
50 Ruahine St, Roslyn, Palmerston North 4442
Country 67694 0
New Zealand
Phone 67694 0
+64 6-356 9169
Fax 67694 0
Email 67694 0
Contact person for public queries
Name 67695 0
Dr Riyaz Bhikoo
Address 67695 0
Palmerston North Hospital
50 Ruahine St, Roslyn, Palmerston North 4442
Country 67695 0
New Zealand
Phone 67695 0
+64 6-356 9169
Fax 67695 0
Email 67695 0
Contact person for scientific queries
Name 67696 0
Dr Riyaz Bhikoo
Address 67696 0
Palmerston North Hospital
50 Ruahine St, Roslyn, Palmerston North 4442
Country 67696 0
New Zealand
Phone 67696 0
+64 6-356 9169
Fax 67696 0
Email 67696 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary