Chapter 35: Back Pain

INTRODUCTION

THE MANAGEMENT OF SPINE DISORDERS IS A KEY competency of physical medicine and rehabilitation. Physiatrists commonly take a lead role in the initial evaluation and management of patients with spine disorders. This chapter aims to discuss common disorders of the neck and low back.

EPIDEMIOLOGY

Neck and back pain are common ailments of the musculoskeletal system. Nonspecific low back pain is one of the most common reasons for physician visits, with a lifetime prevalence of 80%. Only the common cold/upper respiratory infection is more responsible for patient visits to primary care physicians.^1,2 The direct medical costs to manage low back pain is upwards of $20 billion annually.³ The lifetime prevalence of neck pain is between 50% and 67%.⁴

NECK PAIN

Anatomy

The cervical spine consists of seven vertebrae. The atlanto-occipital joint is a major joint for cervical flexion and extension and is innervated by the C1 ventral ramus. The atlantoaxial joint consists of the anterolateral C1–C2 joints and the pivot of the dens of C2 on C1. The lateral atlantoaxial joint is innervated by the C2 ventral ramus. The articulation between the dens and C1 is innervated by the sinuvertebral nerves of C1–C3. Cervical rotation is 70 to 90 degrees with 40 to 45 degrees occurring at the C1–C2 joint.⁵ The C2–C3 facet joint is innervated by the medial branch (third occipital nerve) and articular branch of the posterior ramus of C3.⁶ The cervical facet joints from C3–T1 have an anterior to posterior, cephalad to caudad orientation, allowing for cervical lateral bending, greatest at C3–C4 and C4–C5, and cervical flexion and extension motion greatest at C5–C6 and C6–C7⁵ (Fig. 35–1). The loss of motion due to facet joint disease is due to the more coronal orientation of the facet joints.^5,7 The cervical facet joints are innervated by the medial branch of the dorsal ramus of the spinal nerve above and below the joint. The posterior cervical muscles are innervated by the cervical dorsal rami, while the anterior and lateral neck muscles are innervated by the cervical ventral rami. The intervertebral discs have a complex innervation that includes the posterior vertebral plexus (made up of the sinuvertebral nerves), anterior cervical plexus (made up of branches of the cervical sympathetic trunk), and vertebral nerve (branches of the cervical gray rami communicans)^5,7 (Fig. 35–2).