COVID-19 studies are our top priority. For all other studies, we recommend commencing the registration process concurrently with your ethics submission and allowing at least 8 weeks for registration to be completed from date of first submission as we are experiencing 4 week turn-around time in review of submissions and resubmissions. We currently do not have the capacity to expedite reviews.

Note also there are additional delays to review of updates. We appreciate your patience.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
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
Study of the role of bacterial infection as the predominant cause for back pain
Scientific title
DISC (Degenerate- disc Infection Study with Contaminant control) : Evaluation of the role of infection in degeneration of disc by comparison of the rate of infection in disc samples in degenerative and non-degenerative spine cases
Secondary ID [1] 289056 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Back pain 298496 0
Neck pain 298497 0
Sciatica 298498 0
Arm pain 298525 0
Condition category
Condition code
Musculoskeletal 298582 298582 0 0
Other muscular and skeletal disorders
Infection 298583 298583 0 0
Studies of infection and infectious agents

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Our study aims to look at infection rate in disc samples in degenerative spine disease. Samples of disc were obtained during surgery in participants undergoing discectomy and prolonged cultures were performed . Samples obtained from paraspinal tissue(fat /ligamentum flavum/muscle removed routinely at surgery) with prolonged cultures acted as the internal control for contamination. If disc culture was positive and paraspinal tissue was negative it was presumed as true infection , if both were positive then it was presumed as contamination.
Duration of follow up: sample obtained during surgery with no further follow-up.
Intervention code [1] 294555 0
Not applicable
Comparator / control treatment
Infection rate in disc samples in non-degenerative spine disease( trauma/tumour/scoliosis)
Control group

Primary outcome [1] 298078 0
True infection rate- This was presumed when disc culture was positive and paraspinal tissue ( fat/ligamentum flavum / muscle) culture was negative.
Timepoint [1] 298078 0
at the time of surgery
Secondary outcome [1] 323116 0
contamination rate in spine surgery -the rate of paraspinal tissue being positive whether along with the disc samples or on thier own.
Timepoint [1] 323116 0
at the time of surgery
Secondary outcome [2] 323184 0
proportion of samples with MODIC type 1 and 2 changes on MRI showing true infection(positive culture on disc sample with negative paraspinal tissue)
Timepoint [2] 323184 0
at the time of surgery for true infection rate and for MRI scans preoperative scans ( within 6 months of surgery)
Secondary outcome [3] 326690 0
Inflammatory signs on histopathological evaluation of the disc samples

The subset of patients were consecutive patients from a single centre from midway through the study till the end of the study. In total there were 200 patients
Timepoint [3] 326690 0
At the time of surgery

Key inclusion criteria
1. Patients undergoing discectomy (cervical/thoracic or lumbar)
2. Age > 18 yrs
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Discitis
2. Systemic infection
3. Patients refusing consent
4. Pregnant women

Study design
Case control
Statistical methods / analysis
Effect size= 30% difference
Power= 80%
level of statistical significance= p<0.05
Sample size case and controls

Comparison Infection Rate Required Sample Size
Degenerated Disc vs Controls 0.45 vs 0.05 283 vs 11 Total 295
MODIC type 1 vs Type 2 0.50 vs 0.30 73 vs 167 Total 239
Disc prolapsed vs none cases 0.50 vs 0.35 458 vs 115 Total 573
Calculations with continuity correction
Total sample size for the study is estimated at 580 cases and 20 controls
In addition to descriptive statistics outlining infection and contamination rates along with the associated 95% confidence intervals, generalized linear models with a binary response set will be used to compared locations and adjust for confounding factors and any group comparisons(calculated using SPSS (ver 22.0 Armonk, NY: IBM Corp)). Independent samples student T test will be utilized to compare the disc positivity between cases and controls. Probabilities of < 0.05 was considered significant in the models.

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)
Recruitment hospital [1] 5661 0
Prince of Wales Private Hospital - Randwick
Recruitment hospital [2] 5662 0
Prince of Wales Hospital - Randwick
Recruitment hospital [3] 5663 0
St George Hospital - Kogarah
Recruitment hospital [4] 5664 0
St George Private Hospital - Kogarah
Recruitment hospital [5] 5665 0
The Canberra Hospital - Garran
Recruitment hospital [6] 5666 0
Wollongong Hospital - Wollongong
Recruitment hospital [7] 5667 0
Figtree Private Hospital - Figtree
Recruitment postcode(s) [1] 13150 0
2031 - Randwick
Recruitment postcode(s) [2] 13151 0
2217 - Kogarah
Recruitment postcode(s) [3] 13152 0
2500 - Wollongong
Recruitment postcode(s) [4] 13174 0
2525 - Figtree
Recruitment postcode(s) [5] 13153 0
2605 - Garran

Funding & Sponsors
Funding source category [1] 293434 0
Self funded/Unfunded
Name [1] 293434 0
Dr Ralph Mobbs
Address [1] 293434 0
Suite 7, Level 7
Prince of Wales Private Hospital
Barker st
randwick, NSW 2031
Country [1] 293434 0
Primary sponsor type
Dr Ralph Mobbs
Suite 7, Level 7
Prince of Wales private Hospital
Barker st
NSW, Australia, 2031
Secondary sponsor category [1] 292259 0
Name [1] 292259 0
Address [1] 292259 0
Country [1] 292259 0

Ethics approval
Ethics application status
Ethics committee name [1] 294880 0
southeastern sydney health district ethics committee
Ethics committee address [1] 294880 0
Room G61, East wing
Edmund Blacket Building
Prince of Wales Hospital
Barker st
Randwick , NSW 2031
Ethics committee country [1] 294880 0
Date submitted for ethics approval [1] 294880 0
Approval date [1] 294880 0
Ethics approval number [1] 294880 0
Ethics committee name [2] 294881 0
ACT health research ethics commitee
Ethics committee address [2] 294881 0
PO Box 11
act 2606
Ethics committee country [2] 294881 0
Date submitted for ethics approval [2] 294881 0
Approval date [2] 294881 0
Ethics approval number [2] 294881 0

Brief summary
Degenerate intervertebral disc can cause back pain or neck pain and /or arm or leg pain (if compressing on the nerve root). Correlation between MRI scan findings of degenerate disc and back pain is poor. It is not uncommon to find poor correlation between arm or leg pain symptoms and degree of compression of the nerve root (on MRI scan). Inflammatory mediators have been implicated as the cause for this discrepancy. A few investigators have found infection of disc by low virulent organisms in these degenerate discs and in sciatica in a surprising 45% of cases. The organisms found are skin commensals and there is a high likelihood that these are contaminants. Treating all back pain or sciatica patients with long-term antibiotics is unreasonable and harmful without a strong proof of infection. Unfortunately these studies are underpowered and do not have a stringent contaminant control arm.
Primary: To find the rate of true infection in degenerate discs
Secondary: To find the risk factors for true infection
Proposal research design
This is a case control study comparing incidence of true infection of intervertebral disc in degenerate disc disease patients undergoing spine surgery to patients undergoing spine surgery without degenerate disc (trauma/scoliosis/tumour).
All patients undergoing discectomy for various indications will be eligible to participate. At the time of surgery, disc removed as a part of the intended procedure (discectomy or fusion) will be sent for culture. A small amount of tissue generally removed as a part of the procedure (fat/muscle/ligamentum) will serve as contamination control and will also be sent for culture.
Prolonged cultures will be performed to identify low virulent organisms. Data collected will include demographic data (age, sex, pre-existing health problems, diabetes, smoking, medications, immunocompromised status, smoking, family history etc), radiological data and type of surgery.
If the disc culture is positive and other tissue culture is negative it will be assumed to be infected. But if the other tissue is also positive then it is presumed to be contamination.
Two other arms were added to the original study:

. 1. Contamination (Sham) arm: paraspinal cultures were also undertaken in patients undergoing spinal surgery without discectomy. We aim to obtain contamination rate from this cohort.
2. Histopathological arm: A subset of patients also underwent histopatholgical evaluation to review inflammatory changes in the disc samples. this was planned to augment the notion of disc infection in degenerated discs
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 65322 0
Dr Prashanth J rao
Address 65322 0
Department of Neurosurgery
Prince of Wales Hospital
Barker st
NSW 2031
Country 65322 0
Phone 65322 0
Fax 65322 0
Email 65322 0
Contact person for public queries
Name 65323 0
Dr Prashanth J Rao
Address 65323 0
Department of Neurosurgery
Prince of Wales Hospital
Barker st
NSW 2031
Country 65323 0
Phone 65323 0
Fax 65323 0
Email 65323 0
Contact person for scientific queries
Name 65324 0
Dr Prashanth J Rao
Address 65324 0
Department of Neurosurgery
Prince of Wales Hospital
Barker st
NSW 2031
Country 65324 0
Phone 65324 0
Fax 65324 0
Email 65324 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