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Trial registered on ANZCTR

Registration number

ACTRN12616000541404

Ethics application status

Approved

Date submitted

21/04/2016

Date registered

27/04/2016

Date last updated

11/08/2016

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]

None

Universal Trial Number (UTN)

U1111-1182-1594

Trial acronym

DISC

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Back pain

Neck pain

Sciatica

Arm pain

Condition category

Condition code

Musculoskeletal

Other muscular and skeletal disorders

Infection

Studies of infection and infectious agents

Intervention/exposure

Study type

Observational

Patient registry

False

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]

Not applicable

Comparator / control treatment

Infection rate in disc samples in non-degenerative spine disease( trauma/tumour/scoliosis)

Control group

Active

Outcomes

Primary outcome [1]

True infection rate- This was presumed when disc culture was positive and paraspinal tissue ( fat/ligamentum flavum / muscle) culture was negative.

Timepoint [1]

at the time of surgery

Secondary outcome [1]

contamination rate in spine surgery -the rate of paraspinal tissue being positive whether along with the disc samples or on thier own.

Timepoint [1]

at the time of surgery

Secondary outcome [2]

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]

at the time of surgery for true infection rate and for MRI scans preoperative scans ( within 6 months of surgery)

Secondary outcome [3]

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]

At the time of surgery

Eligibility

Key inclusion criteria

1. Patients undergoing discectomy (cervical/thoracic or lumbar)
2. Age > 18 yrs

Minimum age

18 Years

Maximum age

No limit

Sex

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

Purpose

Screening

Duration

Cross-sectional

Selection

Case control

Timing

Prospective

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

Recruitment status

Completed

Date of first participant enrolment

Anticipated

Actual

9/12/2013

Date of last participant enrolment

Anticipated

2/05/2016

Actual

2/05/2016

Date of last data collection

Anticipated

Actual

21/05/2016

Sample size

Target

600

Accrual to date

Final

578

Recruitment in Australia

Recruitment state(s)

ACT,NSW

Recruitment hospital [1]

Prince of Wales Private Hospital - Randwick

Recruitment hospital [2]

Prince of Wales Hospital - Randwick

Recruitment hospital [3]

St George Hospital - Kogarah

Recruitment hospital [4]

St George Private Hospital - Kogarah

Recruitment hospital [5]

The Canberra Hospital - Garran

Recruitment hospital [6]

Wollongong Hospital - Wollongong

Recruitment hospital [7]

Figtree Private Hospital - Figtree

Recruitment postcode(s) [1]

2031 - Randwick

Recruitment postcode(s) [2]

2217 - Kogarah

Recruitment postcode(s) [3]

2500 - Wollongong

Recruitment postcode(s) [4]

2605 - Garran

Recruitment postcode(s) [5]

2525 - Figtree

Funding & Sponsors

Funding source category [1]

Self funded/Unfunded

Name [1]

Dr Ralph Mobbs

Address [1]

Suite 7, Level 7
Prince of Wales Private Hospital
Barker st
randwick, NSW 2031
Australia

Country [1]

Australia

Primary sponsor type

Individual

Name

Dr Ralph Mobbs

Address

Suite 7, Level 7
Prince of Wales private Hospital
Barker st
Randwick
NSW, Australia, 2031

Country

Australia

Secondary sponsor category [1]

None

Name [1]

none

Address [1]

none

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

southeastern sydney health district ethics committee

Ethics committee address [1]

Room G61, East wing
Edmund Blacket Building 
Prince of Wales Hospital
Barker st
Randwick , NSW 2031

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

26/08/2013

Approval date [1]

24/09/2013

Ethics approval number [1]

13/218

Ethics committee name [2]

ACT health research ethics commitee

Ethics committee address [2]

PO Box 11
woden
act 2606

Ethics committee country [2]

Australia

Date submitted for ethics approval [2]

18/12/2013

Approval date [2]

15/01/2014

Ethics approval number [2]

ETHLR.13.337

Summary

Brief summary

Introduction 
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. 
Aims
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). 
Methods
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

Contacts

Principal investigator

Name

Dr Prashanth J rao

Address

Department of Neurosurgery
Prince of Wales Hospital
Barker st
Randwick
NSW 2031

Country

Australia

Phone

+61296504766

Fax

[email protected]

Contact person for public queries

Name

Prashanth J Rao

Address

Department of Neurosurgery
Prince of Wales Hospital
Barker st
Randwick
NSW 2031

Country

Australia

Phone

+61296504766

Fax

[email protected]

Contact person for scientific queries

Name

Prashanth J Rao

Address

Department of Neurosurgery
Prince of Wales Hospital
Barker st
Randwick
NSW 2031

Country

Australia

Phone

+61296504766

Fax

[email protected]

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Degenerate-disc Infection Study with Contaminant Control: Discussion on the Research Methods.	2018	https://dx.doi.org/10.1111/os.12366
Embase	Degenerate-disc infection study with contaminant control (DISC): a multicenter prospective case-control trial.	2020	https://dx.doi.org/10.1016/j.spinee.2020.03.013

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically