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Trial registered on ANZCTR

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

Titles & IDs
Public title
ACRP Study (Anterior Cervical Retraction Pressure Study)
Scientific title
A comparison of intra-operative retraction pressure during anterior cervical surgery between a novel retractor system and conventional retractor system – a pilot study.
Secondary ID [1] 683 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
voice change 3189 0
dysphagia 3567 0
sore throat 3568 0
Condition category
Condition code
Surgery 3352 3352 0 0
Other surgery

Study type
Description of intervention(s) / exposure
In this study the recruited candidates are prospectively randomized into two groups. In one group Casper retraction system will be used and in the other group Seex's retraction system will be used for anterior cervical surgical procedures. For each patients one procedure will be done with one retractor system. In all the patients an online pressure transducer (Tekscan pressure measurement system) will be applied to the rear side of the medial retractor blade on to the food pipe and pressure changes will be recorded electronically throughout the period of retraction.
The retractor system randomized for a particular patient will be used through out the period of retraction which is needed to complete the proposed procedure. Retraction period may vary between patients
proposed period of study is 18 months.
Intervention code [1] 3281 0
Treatment: Devices
Comparator / control treatment
The group with conventional retractor system
Control group

Primary outcome [1] 4241 0
The retraction pressure on wind pipe and food pipe in patients under going neck operations using the conventional Casper retraction system and Seex retractor system.
Timepoint [1] 4241 0
Continuously throughout the period of retraction
Secondary outcome [1] 7164 0
A self-assessment of sore throat, difficulty in swallowing and voice change by the participants using a chart of rating score.
Timepoint [1] 7164 0
24 hrs, 1 week and 4weeks after operation

Key inclusion criteria
All the patients scheduled for spinal operations from the front of the neck in Nepean hospital, Kingswood, NSW
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
previous neck operations, radiation to the neck or those with history of tumors

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomization information is kept in serially numbered sealed opaque envelopes. Those envelopes are kept in the office of the Head of neurosurgery Nepean hospital. The recruited candidates are serially numbered as per the order in which they are coming to theater for operation. This serial number will be used for randomization purpose. Operation theater staff contacts the office of the Head of neurosurgery and finds out which retractor system is randomized for the serial number
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomization by using a randomization table created by an online computer program (
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 3746 0
Self funded/Unfunded
Name [1] 3746 0
Ananthababu Pattavilakom
Address [1] 3746 0
Dept of Neurosurgery, Nepean Hospital
Derby st
NSW 2751
Country [1] 3746 0
Primary sponsor type
Nepean Hospital
Derby st
NSW 2751
Secondary sponsor category [1] 3145 0
Name [1] 3145 0
Address [1] 3145 0
Country [1] 3145 0

Ethics approval
Ethics application status
Ethics committee name [1] 5540 0
The Sydney West Area Health Service HREC, Nepean Campus
Ethics committee address [1] 5540 0
Nepean Campus
Derby st
NSW 2751
Ethics committee country [1] 5540 0
Date submitted for ethics approval [1] 5540 0
Approval date [1] 5540 0
Ethics approval number [1] 5540 0
HREC Project No. 07/007:

Brief summary
Operations of the spine, when performed from the front of the neck can cause problems like sore throat, difficulty in swallowing and voice change during postoperative period. Often these problems are temporary, but they are common. Most of the patients feel these symptoms are very uncomfortable. These symptoms are attributed to the retraction of structures like wind pipe and food pipe during the operation. The retraction causes pressure on to these structures and results in direct damage as well as damage due to reduced blood flow during the period of retraction. The more the pressure the more will be the damage and the worse will be the symptoms. Conventional retractor systems are designed to mount directly on to the soft tissues during the operation, causing direct transmission of retraction pressure on to them. A novel retractor system (Seex retractor system) has been introduced in to surgical practice. The new system is mounted/fixed directly on to the bones (vertebrae) during the procedure so that the amount of direct pressure transmission to wind pipe or food pipe is theoretically much less than the conventional retractors. Cadaver studies conducted by the researchers agree with that. In this pilot study the researchers prospectively measure the pressure variations on windpipe and food pipe in the two groups of patients under going neck operations with conventional retraction system and the new system. They will also assess sore throat, difficulty in swallowing and voice change in patients of both the groups during postoperative period using rating score chart. Data collected in this unblinded pilot study will be used to design a subsequent randomized controlled trial, if the new system appears to be a better one.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 28618 0
Address 28618 0
Country 28618 0
Phone 28618 0
Fax 28618 0
Email 28618 0
Contact person for public queries
Name 11775 0
Ananthababu Pattavilakom
Address 11775 0
Dept of Neurosurgery, Nepean Hospital
Derby st
NSW 2751
Country 11775 0
Phone 11775 0
(02) 47342000
Fax 11775 0
Email 11775 0
Contact person for scientific queries
Name 2703 0
Ananthababu Pattavilakom
Address 2703 0
Dept of Neurosurgery, Nepean Hospital
Derby st
NSW 2751
Country 2703 0
Phone 2703 0
(02) 47342000
Fax 2703 0
Email 2703 0

No information has been provided regarding IPD availability
Summary results
No Results