Inversion Tables - Research

Found an article on the "hooked on evidence" section on the APTA website. I'll post here in case anyone's interested (a link would be useless if you're not a member):

1. A comparison of inverted spinal traction and conventional traction in the treatment of lumbar disc herniations
Guevenol K, Tuzun C, Peker O, Goktay Y
Physiother Theory Pract 2000; 16(3): 151-160

Target Condition:
722 - Intervertebral disk disorders
722.7 - Intervertebral disk disorder with myelopathy

Element of Patient/Client Management Model: Intervention
Practice Pattern(s):
Musculoskeletal - Pattern F: Impaired Joint Mobility, Motor Function, Muscle Performance, Range of Motion, and Reflex Integrity Associated With Spinal Disorders
Design Type: Clinical Trial, Random
Study Population: Adults (18-64 years)
Population Location: Outpatient / ambulatory care
Inclusion Criteria: Complaint of low back and lower extremity pain of not less than one month duration. All patients had lumbar disc herniation diagnosed by CT. All subjects of study had disc pathology at one or both levels of L4-L5 and L5-S1.
Exclusion Criteria: No history of spinal surgery. Patients with history of cerebrovascular accident, thyroid disease, hiatus hernia, glaucoma, detachment of retina, hypertension, cardiac disorders, chronic obstructive and restrictive lung disorder, osteoporosis, and excessive joint laxity were excluded. Also, two subjects were excluded because of incongruity in CT levels before and after the treatment. Two patients, one of whom had had a traffic accident and one, who had lifted a heavy load were excluded from the study. Patients were not allowed to take nonsteroidal anti-inflammatory drugs throughout the study (only analgesics were given as needed).
How were subjects selected: Not Described
How many subjects were contacted initially: 29
How many subjects were eligible to participate: 25
How many subjects agreed to participate: 25
Non-clinical characteristics of study participants: Mean age 33.8 years (sd 6.0), mean 163 cm (sd 6.9), and mean weight 68.5 kg (sd 10.2) in the inversion traction group and 39.6 years (sd 5.8), 165.3 cm (sd 9.5), and 73.5 (sd 13.0) in the conventional traction group.
Clinical characteristics of study participants: Average pain duration was 28.5 months (sd 26.5) for the inversion traction group and 39.3 months (sd 39.2) for the conventional traction group.
Blinded Clinicians: No
Blinded Subjects: No
Same person providing treatment and testing measures: Not Provided
Blinded assessor: Not Provided
Intention to treat analysis: Not Provided
Treatment Group 1 : Conventional static traction was applied to the first group of 15 patients. Each patient was in the supine position on the traction table with his or her legs in semi-flexion. The initial traction force was 30 kg and it was gradually increased up to 45 kg with 3 kg increments daily, according to the patient’s tolerance. The duration of the traction was 20 minutes. Traction was administered for 10 days. Both treatment 1 and treatment 2 received infrared radiation for 15 minutes to heat superficial tissues, together with abdominal and gluteal isometric exercises.
Treatment Group 2 : Inversion traction was applied to the second group of 16 patients through the use of a tilt table that was specially modified according to Sheffield’s description. With the patient lying supine, ankle straps with padded clothe material were wrapped around the ankles and mounted to the foot of the table. A lumbar strap was placed across the abdominal region of the patient and fastened to permit slide in a vertical direction, but stabilizing the patient’s movements in other directions. Thus, the strap could have no effect on the results. The table was rotated until the patient was upside down, in an inverted position. During this procedure, the table was rotated gradually, according to the patient’s tolerance. The patient was inverted for 5 minutes on the first day of treatment, 8 minutes on the second, and 10 minutes on the third day and onwards through 7 days. Brachial blood pressure of each patient was measured before the treatment and at the third, fifth, and eight minutes of the first treatment period. None of these measurements were continued during the remaining treatment sessions if the change in blood pressure during the first session did not exceed 20 mm of Hg. Traction was administered for 10 days.
Authors Stated Purpose: The purpose of this investigation of lumbar disc herniation patients was to compare the efficacy of the inversion spinal traction and the conventional mechanical spinal traction on several clinical parameters and computed tomography.
Interventions:

Therapeutic Exercise
* Muscle strength, power, and endurance training

Physical Agents
* light agents
* infrared

Mechanical Modalities
* Traction devices
* Positional
* Sustained

Study Outcomes:

Pathology/Pathophysiology
* other

Impairments
* Musculoskeletal
* muscle performance (strength, power, endurance)
* pain

Results By Outcome:
Outcome 1 - continuous
disc protrusion (mm) from CT scan

I.
Treatment 1 and Treatment 2
Absolute Mean Difference: 0.58
Standardized Mean Difference: 0.27 (95% Confidence Interval : -0.49 to 1.03)

-10
Favors Treatment 1 0 10
Favors Treatment 2

disc protrusion (mm) from CT scan

II.
Treatment 1
Number of Subjects: 13
End Mean: 5.70
End Standard Deviation: 1.96
Baseline Mean: 6.62
Baseline Standard Deviation: 1.58
Treatment 2
Number of Subjects: 14
End Mean: 5.12
End Standard Deviation: 2.37
Baseline Mean: 5.04
Baseline Standard Deviation: 1.59

Outcome 2 - dichotomous
Persons with a decrease in the amount of disc protrusion from CT scan

I.
Treatment 1 and Treatment 2
Odds Ratio: 4.05 95% Confidence Interval: 0.81 to 20.20
Risk Ratio: 1.94 95% Confidence Interval: 0.88 to 4.28
NNT: 2.98

Persons with a decrease in the amount of disc protrusion from CT scan

II.
Treatment 1
Subject with Outcome: 9
Subjects without Outcome: 4
Treatment 2
Subject with Outcome: 5
Subjects without Outcome: 9

Authors Conclusions: The article does not report pre and post treatment means for the clinical outcomes, including pain. It is reported that the total pain cluster scores in both groups were significantly improved after treatment, that there was an increase in straight leg raising test and no difference in fingertip to floor distance. Clinical efficacies of the two traction methods were not significantly different from each other. CT efficacy of the conventional traction group was apparently better. Patients seemed to tolerate conventional traction better than inversion.

Reviewer: Heather Mote Date last modified: 08/17/2006
This extraction has been reviewed for accuracy by a member of APTA's Section on Research.