Mechanical Traction

Functional Unit of the Spine

•  TWO adjacent vertebrae & the intervening IVD

•  Motion segment of the spine

•  Anterior – WB

•  Posterior – Mov’t

Pain Sensitive

•  VB

•  IVD

•  Outer 1/3 AF

•  ALL

•  PLL

•  Facet

•  NR

•  Muscle

Pain Tolerance

•  Nucleus Pulposus

•  Outer 2/3

Injury to the MOTION SEGMENT:

•  Spondylosis- Degeneration of the intervertebral disc

•  Spondylolysis- Defect in the pars interarticularis or the arch of the vertebra

•  Spondylolisthesis- Forward displacement of one vertebra over other

•  Retrolisthesis- backward displacement of one vertebra on another

Annulus Fibrosus

•  Outer laminated portion the disc

•  Contains 20 concentric, collarlike rings of collagenous fibers that criss-cross each other to increase their strength & accommodate torsion movements

•  Three Zones

•  Outer Zone – Sharpey’s Fibers

Nucleus Pulposus

•  At birth, hydrophilic mucoid tissue

•  Gradually replaced by fibrocartilage 

•  Water-binding capacity of the disc decreases with age, and degenerative changes (spondylosis)

•  Initially, the disc contains approximately 85% to 90% water

•  Decreases to 65% with age

• Adheres to the vertebral body by means of the cartilaginous end plate

• Avascular, with only the periphery receiving a blood supply

• Receives nutrition by diffusion, primarily through the cartilaginous end plate

• Until the age of 8 years, IVD have some vascularity, decreases with age

Aneural

• Posterior periphery of the AF – nerve supply?

• Direct vertical pressure on the disc can cause the disc to push fluid into VB

• ↑ pressure on the IVD = Schmorl's nodules

• Herniations of the NP into the VB

• Normally, an adult is 1 to 2 cm (0.4 to 0.8 inch) taller in the morning than in the evening (20% diurnal variation)

Herniation

• Localized displacement of disc material beyond the normal margins of the disc,

• Defined circumferentially by the outer edges of the ring apophyses of the vertebral body end plates &, by the end plates above and below the disc space

IVD Herniation

McNab’s Classification

(BPES)

• Bulging

• Prolapsed

• Extrusion

• Sequestration

IVD Herniation can lead to…

• Pressure on the spinal cord itself (upper lumbar spine) leading to a Myelopathy

• Pressure on the cauda equina leading to Cauda Equina Syndrome

• Pressure on the nerve roots (most common)

L5-S1

• MC site of problem in the spine

• Greater WB

• COG passes → ↓ shearing force

• Transition of mobile segment (L5) to fused or stable (S1) segment

• Greater angle compared with other vertebrae

• Large amount of mov’t

• The herniations from the fragments of the nucleus pulposus into the vertebral body is called:

• Schmorl's nodules

Mechanical Effects

• Stretching of muscles and ligaments

• Separation of apophyseal joints

Effect on spinal movement

• Distraction of the vertebral bodies with enlargement of IVF

• 1-2 mm separation per IV space

• ↓ pain, paresthesia while traction is applied

Effects on bone

WOLFF’S LAW

• Bone changes in response to compressive or distractive loads

• Intermittent traction with a rhythmic on & off load cycle provides distraction load & promotes movement

Effects on ligaments

Viscoelactic Property

• Property of ligaments that allow them to resist shear forces & return to their original form following the removal of a deforming load

• Slow loading rates allow the ligament to lengthen as it absorbs the force of the load

Effects on Articular Facet Joints

• Meniscoid structures, synovial fringes, or osteochondral fragments (calcified bone chips) impinged between joint surfaces are released → ↓ symptoms when joint surfaces are separated

Effects on Muscular System

• ↓ EMG activity of Erector Spinae = muscle relxation

• ↑ BF, activation of muscle proprioceptors, Gate Control Theory

Effects of Nerves

• Pressure on nerves or roots from bulging disk material, irritated facet joints, bony spurs, or narrowed foramen size causes the neurologic malfunctioning often associated with spinal pain

• ↑ blood’s circulation to the nerve, ↓ edema and allowing the nerve to return to normal functioning

Parameters

• Position:

• 0-5 cervical fl:  IV space at C1-C5

• 25-30 flexion: for C5-C7

• 0 : disc dysfunction

Force:

• 7% of the body weight

• 10-15 lbs. initial tx.

• 25-30 lbs : elongation of the spine occur

Treatment time:

• 5 – 10 min HNP

• 10-30 min for other conditions

Parameters

Position:

• 45-60  of hip flexion :  IV space at L5-S1

• 75-90  of hip flexion: at L3-L4

Force:

• ½ of body weight : male

• 1/3 of body weight : female

Treatment time:

• 5-10 min for HNP

• 10-30 min for other condition

Major Parameters for the Application of Traction

• Positioning

• Weight to be used

• Duration

• Continuous vs. intermittent application

• Concomitant modalities to be given

INDICATIONS

• Relief of pain from disc herniation

• Radiculopathies

• Patient immobilization as in the treatment of acute disc herniation

CONTRAINDICATIONS

• Inadequate expertise

• Cervical ligament instability

• Underlying tumor or malignancy

• Severe osteopenia

• Vertebro-basilar arterial disease

• Cord compression & infections of the spine

• Old age

• Pregnancy

• RA

2. Sustained Traction

• Is also applied continuously but usually for no longer than 45 - 60 min

• > greater forces can be applied

• Purpose:

• Relaxation of muscles

• Stretching of soft tissue

• separation of bony surfaces

Purposes:

• To separates bony surfaces

• Mobilize the jts

• Stretch soft tissue & relax the muscles around the jt.

Level-specific Manual Traction

• L3 – L4

• L4 – L5

• L5 – S1

  
  

5. Positional Traction

• Applied by positioning the patient in a way that will affect the relationship of the bony surfaces in the area treated

• Duration of treatment is 5 - 30 min

• Can be done unilaterally / bilaterally

• Purpose:

• To alleviate pressure on an entrapped nerve

• Relax the muscle in spasm

6. Gravity - assisted Traction

• Patient is placed in a position that favors distraction

• Duration : 10 - 30 mins

• Permits the gravity to help the overall distraction of targeted tissue

Mechanical Traction

General Parameters:

1. Body position: prone, supine, hip position, bilateral, or unilateral direction of pull

2. Force used

3. Intermittent traction: traction time and rest time

4. Sustained traction

5. Duration of treatment

6. Progressive steps

7. Regressive steps