Table 1 Characteristics of Selected Studies

Khani et al [33] (2015) Iran

- LBP with L3-S1 radiculopathy;

- duration of symptoms < 6 months;

- positive MRI findings;

- no history of previous physical therapy;

- willing to take part in the study by signing a written informed consent.

- red flags indicative of non-mechanical LBP;

- indication of surgery;

- spinal stenosis;

- pregnancy or post-partum period.

Symptoms + physical exam

50 patients, randomized in 2 groups:

● Traction group (n = 25);

● Control group (n = 25).

2 months duration.

1. Autotraction in vertical position by suspension from a pull-up bar + routine medication

➔ Traction rhythm: continuous traction;

➔ Traction frequency: at least 20 times a day, each time for 30 s (or more than it so that the total duration of suspension reached 10 mins in a day);

➔ Traction force: patients’ body weight + gravity;

➔ Combination with other interventions: YES: Drugs (NSAID, Corticosteroids, Muscle relaxants).

2. Routine medication (NSAIDs, corticosteroids and muscle relaxants).

At baseline and after treatment:

- pain (VAS);

- Herniated Index (MRI).

VAS and Herniated Index reduction post-treatment in the traction group were significant.

The clinical effect of pull-up bar traction is substantial.

Moret et al [34]

(1998) The Nederlands

- age between 18 and 60 years;

- LBP with radiculopathy;

- at least two positive signs of radiculopathy: loss of sensitivity, paralysis in the musculature, provocation of symptoms with coughing or sneezing, positive SLR;

- prescription of bed rest for at least 1 and a maximum of 2 weeks.

- signs of non-mechanical LBP with radiculopathy;

- anatomical abnormalities (e.g. trunk-obesity, etc.);

- any disease which may be a contraindication for traction therapy.

Symptoms + physical exam

16 patients randomized in 2 groups:

● Vertical traction + bed rest group (n = 8);

● Bed rest (toilet visits were allowed but must be registered in a diary) only group (n = 8).

At least 1 week and maximum 2 weeks.

1. Vertical traction in sitting position with a belt around the chest + bed rest

➔ Traction rhythm: continuous traction;

➔ Traction frequency: 4 times for 45 mins or 6 times for 30 mins per day;

➔ Traction force: patients’ body weight + gravity.

➔ Combination with other interventions: YES: rest on bed.

2. Bed rest.

At baseline and after 3 weeks:

- activity limitation (RMDQ);

- pain in the leg and in the back (10 point rating scale).

In addition, at baseline and after 2 weeks:

- Global Perceived Recovery;

- Schöber score;

- SLR.

RMDQ mean improvement and mean leg pain reduction were higher in the traction group.

More patients in the study group strongly improved/completely recovered their back pain.

No differences were found regarding global perceived recovery.

SLR improved more in the traction group

No differences were found in Schöber score improvement.

Prasad et al [35]

(2012) United Kingdom

- age between 18 and 45 years;

- duration of symptoms < 6 months;

- signs and symptoms of single level unilateral radiculopathy with decision to operate.

- red flags indicative of non-mechanical LBP;

- pregnancy or postpartum period;

- increasing neurological deficits;

- weight more than 20% of ideal norms for height and age or > 140 kg;

- positive MRI findings.

Symptoms + imaging

24 patients randomized in 2 groups:

● Inversion therapy group + PT (n = 13);

● PT only (n = 11).

Only 22 were eligible for assessment.

4 weeks.

1. Inversion traction in vertical position + PT (education and advice, exercises for movement control and reduction of derangement, and manual therapy)

➔ Traction rhythm: intermittent traction;

➔ Traction frequency: 3 times a week, 6 times 2-min inversion within tolerance;

➔ Traction force: upper half patients’ body weight + gravity;

➔ Combination with other interventions: YES: Physical Therapy (education, motor control exercises for derangement reduction, manual therapy).

2. PT.

At baseline and after 6 weeks:

- activity limitation (RMDQ);

- activity limitation (ODI);

- pain (VAS).

Surgical intervention was avoided in 76.9% of patients in the inversion group, while it was avoided in only 22.2% in the control group.

Patients in the inversion group tended to have less activity limitation at follow-up.