Chapter 7: Spinal Traction

FOUNDATIONS OF TRACTION

The practice of using traction—applying tensile forces to the long axis of the spine—to treat patients with pain associated with the spine has been advocated for centuries. Modern support for traction stemmed largely from British physician James Cyriax, who in the 1940s recommended using traction to treat patients with suspected disc lesions.¹ Practitioners from Cyriax’s time to more recent treatment approaches, including those developed by Australian physiotherapist Geoffrey Maitland, also proposed traction to be of value in treating patients with spinal disorders.^2,3 The rationale for this intervention in patient care may have evolved, but the fundamental concept of its usage has remained remarkably consistent over the years.

In the current evidence-guided era, the use of traction has been more closely examined for effectiveness in patient care. Many practitioners continue to cite traction as an essential clinical modality, often based on patterns observed in patient care experiences, although objective evidence of its value remains limited. In this chapter, the known physiological and biomechanical effects of spinal traction will be described along with the clinical trials employing traction. Additionally, from a practical perspective, the conventional traction methods often used by clinicians along with variations on traditional uses will be described.

BIOMECHANICAL AND PHYSIOLOGICAL EFFECTS OF TRACTION

Cervical Spine

Among the purported effects of traction is increasing the space between the vertebrae. The theorized value of intervertebral separation is for normalizing morphology—more specifically the disc’s position and increasing the dimensions of the intervertebral foramen containing the spinal nerve root. Imaging studies in vivo and with cadaveric specimens have investigated the effects of traction on the cervical spine motion segment toward these theoretical effects.

Studies using fresh cadaveric human specimens⁴ and live subjects⁵ have yielded nearly identical results with the dimensions of the intervertebral foramina increasing during traction when measured with computed tomography (CT) and radiography, respectively. In both studies, traction with the cervical spine in a neutral position significantly increased foraminal size. Combined cervical flexion and traction did not increase foraminal size greater than either flexion or traction alone. Other studies have documented a decrease in pressure within the intervertebral foramen⁶ and an increase in the dimensions of the intervertebral foramen^7,8 with flexion of the cervical spine. Computer simulations have also suggested a flexed position of the cervical spine having a greater effect in the lower cervical spine while traction angle does not change the effect in the upper cervical segments.⁹ Findings of this nature likely serve as the hypothetical basis for including flexion when applying cervical traction. A reduction of mechanical effect focused on the posterior tissues as occurs with flexion of the cervical spine by use of support for the cervical lordosis to balance tensile forces has also been proposed to have potential benefit but has been minimally investigated to date.^10-12