McKenzie Extension Protocol Versus Core Stability Exercises Combined With Spinal Decompression in Discogenic Lumbar Radiculopathy (D-MECS)
McKenzie Versus Core Stability Exercises Along With Spinal Decompression in Discogenic Lumbar Radiculopathy: A Single-Blind Randomized Controlled Trial
The pathophysiology arises from structural and biochemical degeneration within the intervertebral disc rather than direct nerve root compression alone. When radicular symptoms are present, patients frequently experience a combination of localized lumbar pain, radiating leg pain, reduced spinal mobility, and impaired daily function. Non-surgical spinal decompression therapy is frequently employed as a conservative treatment for lumbar disc pathology due to its capacity to reduce intradiscal pressure, increase disc height, and unload compressed neural structures. Nevertheless, decompression alone does not fully restore neuromuscular control or spinal stability; it is consequently commonly paired with an active exercise approach. Two of the most widely utilized adjunct approaches are the McKenzie Extension Protocol, which employs directional-preference movements and repeated end-range loading to promote symptom centralization, and Core Stability Exercises, which target the deep trunk stabilizers to improve segmental control of the lumbar spine. Although each approach is independently supported by evidence, no recent trial has directly compared their effectiveness when each is combined with spinal decompression therapy in patients with MRI-confirmed discogenic low back pain accompanied by radiculopathy. This evidence gap consequently leaves clinicians without clear guidance on which combined strategy to select.
The present study is a single-blind randomized controlled trial designed to determine and compare the effects of the McKenzie Extension Protocol versus Core Stability Exercises, each combined with spinal decompression therapy, on pain intensity, functional disability, and lumbar range of motion in adults with MRI-confirmed discogenic low back pain and radiculopathy. Forty-two participants aged 25-45 years, with a posterolateral disc bulge confirmed on MRI, a Numeric Pain Rating Scale (NPRS) score greater than 3, and a positive Straight Leg Raise test, will be recruited using purposive sampling and randomly allocated by lottery method into two equal groups of 21. Group A will receive spinal decompression therapy followed by McKenzie extension-based exercises, while Group B will receive the same decompression protocol followed by core stabilization exercises such as abdominal drawing-in, bridging, bird-dog, and side-plank variations. Both groups will also receive standardized adjunct modalities, including moist heat and interferential current therapy, and will attend three sessions per week for four consecutive weeks, totaling 12 sessions.
Outcomes will be assessed at baseline and immediately after the four-week intervention period by a blinded assessor to minimize bias. The primary outcome measures include pain intensity (NPRS), functional disability (Oswestry Disability Index), lumbar range of motion (inclinometer), and lower-limb neural mobility (Straight Leg Raise angle). Data will be analyzed using SPSS to compare within-group and between-group changes across the two interventions.
This trial is anticipated to generate direct comparative evidence on which combined rehabilitation strategy, either decompression with McKenzie exercises or decompression with core stability exercises, produces superior clinical outcomes for this patient population. Given that current clinical guidelines do not specify a preferred adjunct approach for discogenic radiculopathy managed with decompression, the findings are intended to assist physiotherapists in selecting more targeted, evidence-based rehabilitation protocols. Such evidence may potentially improve pain relief, functional recovery, and cost-effectiveness of care, while simultaneously reducing the long-term burden associated with chronic low back pain.
Study Overview
Status
Conditions
Detailed Description
Background and Rationale
Low back pain (LBP) ranks among the most prevalent musculoskeletal conditions globally. Point prevalence estimates are roughly 9-12% worldwide, with up to 23% of adults reporting an episode within a one-month period. Lifetime prevalence estimates range as high as 40-80%. Global burden data from 2021 indicate that approximately 453 million working-age adults were affected by LBP. Within this broad population, discogenic low back pain (DLBP) constitutes a distinct subgroup in which pain originates from structural and biochemical changes within the intervertebral disc itself, most often disc degeneration, rather than from nerve root compression or other spinal pathology. Depending on the diagnostic method employed, discogenic pain accounts for approximately 22-50% of chronic low back pain cases. A further subset of these patients develops lumbar radiculopathy, wherein nerve root irritation produces radiating leg pain. Population data suggest that roughly 12% of adults with back pain exhibit clinical radiculopathy, though substantial variation in reported incidence exists depending on the population studied.
Non-surgical spinal decompression is a motorized, computer-controlled traction therapy that applies gentle, feedback-regulated distraction forces to the lumbar spine. It is theorized to reduce intradiscal pressure, transiently increase disc height and foraminal space, and enhance fluid and nutrient exchange within the disc, thereby supporting disc hydration and reducing mechanical loading on degenerated segments. Several recent studies report improvements in pain and disability following non-surgical decompression, particularly when it is combined with conventional physical therapy rather than used in isolation.
Two of the most established adjunct exercise approaches utilized alongside decompression are the McKenzie Method, also known as Mechanical Diagnosis and Therapy (MDT), and Core Stability Exercises. The McKenzie approach is a structured system of repeated movements and sustained positions used to classify patients into mechanical subgroups and guide treatment based on their directional preference. A central therapeutic phenomenon in this approach is centralization, in which distally referred pain progressively retreats toward the spinal midline in response to specific repeated movements, a pattern associated with favorable prognosis. Core stability exercises, by contrast, focus on activating and coordinating the deep trunk musculature, including the transversus abdominis and lumbar multifidus, to improve co-contraction, segmental control, and postural stability, thereby reducing nociceptive input from unstable or overloaded spinal structures.
Existing comparative literature remains mixed. Some studies report that core stabilization produces greater reductions in pain and disability than McKenzie exercises in patients with lumbar radiculopathy, while other trials, including a one-year follow-up RCT among patients with a McKenzie directional preference, found no clear superiority of either approach when compared to motor control or core stability exercises. Evidence specific to discogenic radiculopathy managed with decompression is even more limited. One RCT found that adding spinal decompression to core stabilization produced larger within-group improvements than core stabilization alone, yet no identified trial has directly compared McKenzie-based and core-stability-based exercise protocols when both are paired with decompression therapy in this specific population.
Problem Statement
Given that spinal decompression is widely used as a conservative treatment for lumbar disc pathology, and current guidelines do not specify which adjunct exercise approach, McKenzie or core stability, produces superior outcomes when combined with decompression, clinicians lack clear direction when selecting rehabilitation strategies for discogenic low back pain with radiculopathy. This trial is designed to address that evidence gap directly.
Study Design and Methods
This is a single-blind, two-arm randomized controlled trial to be conducted at the Max Spine Rehab Center, Max Health Hospital. Eligible participants are adults aged 25-45 years with an MRI-confirmed posterolateral disc bulge, an NPRS pain intensity greater than 3 with radicular symptoms, and a positive Straight Leg Raise test. Individuals with a history of spinal surgery or significant trauma, increased kyphosis, active infection, pregnancy, scoliosis, systemic inflammatory disease, or cognitive impairment affecting participation will be excluded. A total of 42 participants, calculated using OpenEpi, will be recruited via purposive sampling and randomized by lottery method into two groups of 21.
Both groups will receive identical spinal decompression therapy, consisting of supine mechanical traction at 25-50% bodyweight force for 10-15 minutes in an intermittent 60-second hold and 30-second release cycle, immediately followed by their assigned exercise protocol. Group A will perform McKenzie-based extension exercises, including prone lying in extension, prone press-ups, standing lumbar extension, and repeated end-range extension guided by directional preference and centralization. Group B will perform core stability exercises, including the abdominal drawing-in maneuver, bridging, bird-dog, and side-plank or modified side support. Both groups will also receive standardized moist heat and interferential current therapy before exercise. Sessions will occur three times weekly for four weeks, totaling 12 sessions, with exercise dosage progressed according to individual tolerance and symptom response.
Outcome Measures
Four outcome domains will be assessed at baseline and post-intervention by a blinded assessor. These include pain intensity via the Numeric Pain Rating Scale (NPRS, 0-10), functional disability via the Oswestry Disability Index (ODI, 0-100%), lumbar range of motion in flexion, extension, and lateral bending via inclinometer, and lower-limb neural mobility via the Straight Leg Raise test angle. All instruments possess established reliability and validity for use in lumbar spine populations.
Data Analysis and Ethics
Data will be analyzed using SPSS to compare within-group and between-group changes across the two treatment arms. The trial will be conducted under Institutional Review Board approval. Written informed consent will be obtained from all participants, and provisions for voluntary participation, the right to withdraw at any time, and the receipt of active therapeutic intervention in both study groups will be ensured throughout.
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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Islamabad, Pakistan
- Max Spine Rehab Center, Max Health Hospital
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
- Adult
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Adults aged 25-45 years (both males and females)
- MRI-confirmed posterolateral disc bulge
- Pain intensity greater than 3 on the Numeric Pain Rating Scale (NPRS) with radiculopathy
- Positive Straight Leg Raise (SLR) test
Exclusion Criteria:
- History of spinal surgery or significant spinal trauma
- Increased kyphosis or active infectious disease
- Pregnancy, scoliosis, or systemic inflammatory conditions
- Cognitive impairments that may interfere with participation or assessment
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Single
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
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Experimental: Group A (McKenzie Extension Protocol with Spinal Decompression)
Participants will receive mechanical spinal decompression followed by a McKenzie Extension Protocol, including prone lying with lumbar extension, prone press-ups, standing lumbar extension, and repeated end-range extension exercises based on directional preference.
Adjunct therapy includes moist heat and interferential current.
Treatment will be administered three sessions per week for four weeks (12 sessions total).
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McKenzie Extension Protocol: prone lying extension, prone press-ups, standing lumbar extension, and repeated end-range extension based on directional preference. 3 sessions/week for 4 weeks (12 sessions total). Spinal decompression: mechanical traction, supine, 25-50% bodyweight, 10-15 min, intermittent 60s hold/30s release. Moist heat (10-15 min) Interferential current (IFC, 10-15 min, 80-100 Hz). 3 sessions/week for 4 weeks (12 sessions total). |
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Active Comparator: Group B (Core Stability Exercises with Spinal Decompression)
Participants will receive the same spinal decompression protocol followed by a Core Stability Exercise program consisting of abdominal drawing-in maneuvers, bridging, bird-dog, and side plank exercises.
Adjunct therapy includes moist heat and interferential current.
Treatment will be administered three sessions per week for four weeks (12 sessions total).
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Spinal decompression: mechanical traction, supine, 25-50% bodyweight, 10-15 min, intermittent 60s hold/30s release. Moist heat (10-15 min) Interferential current (IFC, 10-15 min, 80-100 Hz). 3 sessions/week for 4 weeks (12 sessions total).
Core Stability Exercises: abdominal drawing-in maneuver, bridging, quadruped bird-dog, and side plank/modified side support 3 sessions/week for 4 weeks (12 sessions total).
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Pain Intensity
Time Frame: Baseline and after 4 weeks of intervention
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Pain intensity will be assessed using the Numeric Pain Rating Scale (NPRS), an 11-point self-reported scale ranging from 0 (no pain) to 10 (worst imaginable pain).
A reduction in NPRS score indicates improvement in pain intensity.
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Baseline and after 4 weeks of intervention
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Functional Disability - Oswestry Disability Index (ODI)
Time Frame: 10-item self-reported questionnaire scored as a percentage of disability; assessed at baseline and post-intervention (4 weeks).
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10-item self-reported questionnaire scored as a percentage of disability; assessed at baseline and post-intervention (4 weeks).
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Lumbar Range of Motion - Inclinometer Measurement
Time Frame: Flexion, extension, and left/right side bending measured in degrees using a dual inclinometer; assessed at baseline and post-intervention (4 weeks).
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Flexion, extension, and left/right side bending measured in degrees using a dual inclinometer; assessed at baseline and post-intervention (4 weeks).
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Collaborators and Investigators
Study record dates
Study Major Dates
Study Start (Actual)
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
- IIUI/RERC/ADT/2026/01/218
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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