centralization and the correlation to discogenic pain

Critical Appraisal for a Reference-Standard Validity Study


P: For patients with chronic low back pain, with varying levels of distress,

I: can the centralization phenomenon

C: as compared to discography results

O: provide diagnostic power for discogenic pain



Vincent Gutierrez, PT, MPT, cert. MDT



Ovidsp with keyword terms “low back pain and centralization and specificity and sensitivity”.   44 citations were found between the years 2004 and 2014.


Date of Search: January 21,2014

Re-evaluation date: January 25, 2014



Laslett M, Oberg B, Aprill C, McDonald B. Centralization as a predictor of provocation discography results in chronic low back pain, and the influence of disability and distress on diagnostic power. Spine Journal 2005;5:370-380.



This validation study has two purposes. The first is to investigate the predictive value of the centralization phenomenon (CP) in relation to provocation discography, which is the only reference standard available for discogenic pain. The second is to investigate the role of distress and disability with regards to the predictive value of the centralization phenomenon in relation to provocation discography.


The inclusion criteria were patients with persistent low back pain (LBP), with or without lower extremity (LE) symptoms, whom were referred to a private radiology practice. Patients were excluded for the following reasons: a normal magnetic resonance imaging (MRI) assessment, severe degeneration associated with spondylolisthesis, and if the discography was contraindicated or a referral ruled out discography. The patients that were included were assessed consecutively.


Prior to the evaluation by a physical therapist, the patient completed a visual analog scale (VAS) for pain and the Roland-Morris Disability Questionnaire (RMDQ). The Zung Depression Index (ZDI), Modified Somatic Perception Questionnaire (MSPQ) and the Distress Risk Assessment Method (DRAM) were also completed prior to the physical therapy (PT) evaluation. The evaluation was performed prior to the discography and the physician performing the discography was blinded to the therapist’s results. The therapist was blinded to the results of the subjective outcome measures.


The physical evaluation consisted of a McKenzie evaluation. The exam required 30-60 minutes and also included sacro-iliac joint (SIJ) provocation tests. Centralization or peripheralization was noted and at this point the examination was terminated.


Discography was performed using standard technique and the patient was required to report pain in at least one disc, without pain at an adjacent disc in order to receive a positive test result.


One hundred eighteen patients participated in the PT evaluation and discography. One hundred seven patients were included in the initial analysis. Of the 107 patients, 69 received a full PT evaluation, 21 received a partial evaluation and 17 did not receive an evaluation. Of the above, the physical therapist offered an opinion regarding CP for 83 patients.



The authors utilized the only reference standard studied, provocation discography, in order to determine if CP is predictive of discogenic pain. The physician was blinded to the physical therapists’ evaluation and the physical therapist was blinded to the patients subjective outcome measures. Not all patients received both the PT evaluation and discography.


The confidence interval was 95%. For non-distressed patients, the following statistical measures were calculated: sensitivity of 37%, specificity of 100%, positive likelihood ratio (LR+) and negative likelihood ratio (LR-) were incalculable due to a specificity of 100%. For distressed patients, the following statistical measures were calculated: sensitivity of 45%, specificity of 89%, LR+ of 4.1, and LR- of 0.61. For not severely disabled patients, the following statistical measures were calculated: sensitivity of 35%, specificity of 100%, LR+ and LR- are incalculable due to 100% specificity. For severely disabled persons, the following statistical measures were calculated: sensitivity of 46%, specificity of 80%, LR+ of 3.2 and LR- of 0.63



Performing a McKenzie evaluation in order to determine the presence of CP is a good test for determining a positive discography, especially in patients without severe disability or distress. The presence of CP improves the pre-test probability to post-test probability of positive discography from 39% to greater than 75% in patients with severe disability or distress. CP is a strong predictor of positive discography in patients without severe distress or disability.

Author: Dr. Vince Gutierrez, PT, cert. MDT

After having dedicated 8 years to growing my knowledge regarding the profession of physical therapy, it seems only fitting that I join the social media world in order to spread a little of the knowledge that I have gained over the years. This by no means is meant to act in place of a one-one medical consultation, but only to supplement your baseline knowledge in which to choose a practitioner for your problem. Having completed a Master of Physical Therapy degree, the MDT (Mechanical Diagnosis and Therapy) certification and currently finishing a post-graduate doctorate degree, I have spent the previous 12 years in some sort of post-baccalalaureate study. Hopefully the reader finds the information insightful and uses the information in order to make more informed healthcare decisions. MISSION STATEMENT: My personal mission statement is as follows: As a professional, I will provide a thorough assessment of your clinical presentation and symptoms in order to determine both the provocative and relieving positions and movements. The assessment process and ensuing treatment will be based on current and relevant evidence. Furthermore, I will educate the patients regarding their symptoms and their likelihood of improving with either skilled therapy, an independent exercise program, spontaneous recovery or if the patient should be referred to a separate specialist to possibly provide a more rapid resolution of symptoms. Respecting the patient’s limited resources is important and I will provide an accurate overview of the prognosis within 7 visits, again based on current research. My goal is to empower the patient in order to take charge of both the symptomatic resolution and return to full function with as little dependence on the therapist as possible. Personally, I strive to be an example for family and friends. My goal is to demonstrate that success is not a byproduct of situations, but a series of choices and actions. I will mentor those, in any way possible, that are having difficulty with the choices and actions for success. I will continue to honor my family’s “blue-collar” roots by working to excel at my chosen career and life situations. I choose to be a leader of example, and not words, all the while reducing negativity in my life. I began working towards the professional aspect of the mission statement while still in physical therapy school. By choosing an internship that emphasized patient care and empowering the patient, instead of the internship that was either closest to home or where I knew that I would have the easiest road to graduation, I took the first step towards learning how to utilize the evidence to teach patients how to reduce their symptoms. I continued this process by completing Mechanical Diagnosis and Therapy courses A-D and passing the credentialing exam. I will continue to pursue my clinical education through CEU’s on MDT and my goal is to obtain the status of Diplomat of MDT. Returning back to school for the t-DPT was a major decision for me, as resources (i.e. time and money) are limited. My choice was between saving money for the Dip MDT course (about 15,000 dollars) and continuing on with the Fellowship of American Academy of Orthopedic Manual Physical Therapists (FAAOMPT) (about 5,000 dollars), as these courses are paired through the MDT curriculum or returning to school to work towards a Doctorate of Physical Therapy degree. I initially planned on saving for the Dip MDT and FAAOMPT, but life changes forced me to re-evaluate my situation. The decision then changed to return for the tDPT, as my employer paid for a portion of the DPT program. My goal for applying to and finishing the Dip MDT and FAAOMPT is 10 years. This is how long I anticipate that it will take to finish paying student loans and save for both programs, based on the current rate of payment. I don’t know if I will ever accomplish what I set forth in the mission statement, but I do know that it will be a forever struggle to maintain this standard that I set for myself.

One thought on “centralization and the correlation to discogenic pain”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s