Thoracic and Lumbar Spine
Reginald S. Fayssoux
INTRODUCTION AND EPIDEMIOLOGY
Back pain is a frequent complaint and source of morbidity among athletes in all sports, with low back pain accounting for 5%-8% of injuries (10).
Nearly 15% of spinal injuries (cervical, thoracic, and lumbar) in the United States relate to participation in a sport or recreational activity. Depending on the mechanisms of applied load, different patterns of spinal injury are possible; thus, certain sports are predisposed to certain injury patterns.
Musculoligamentous injuries of the paraspinal musculature are common to all sports that involve trunk rotation (e.g., golf, baseball, tennis), contact (e.g., basketball, football, soccer), or repetitive injury mechanisms (e.g., gymnastics, swimming, diving, volleyball).
Full-contact collision sports, such as American football, ice hockey, and rugby, are a common cause of spinal injury. The most common injuries involve the cervical spine. Thoracic and lumbar injuries occur less frequently. A classic example is spondylolysis in linemen resulting from repeated lumbar hyperextension.
High-speed sports such as downhill skiing and snowboarding are relatively common causes of spine injury. Impact speeds are typically much higher than in other sports. Risk factors for injury include poorly groomed slopes, equipment failure, unfavorable weather conditions, overcrowding, skier error, and skier loss of control (1). The reported incidence of spine injuries among snowboarders is three to four times higher than among skiers. Jumping is responsible for as many as 80% of spine injuries among snowboarders and typically affects the thoracolumbar region (7).
With the aging population being more and more active, spinal injuries are occurring in older patients with preexisting degenerative spinal changes, resulting in evaluation and treatment challenges. Decisions regarding return to play are especially complex in these patients, especially when surgery has been done or is being considered.
ANATOMY
The spinal column allows for controlled spinal motion while protecting the enclosed neural elements.
Osseous Anatomy
The spinal column is the foundation of the axial skeleton, extending from the base of the skull to the pelvis with articulations to the rib cage.
The spinal column is composed of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4-5 coccygeal vertebral segments. The cervical, thoracic, and lumbar vertebrae are separated by intervertebral discs.
Normally, the spine positions the head directly over the pelvis in the coronal and sagittal planes (i.e., coronal and sagittal balance). In the coronal plane, the spine is straight. In the sagittal plane, the cervical and lumbar regions are lordotic, whereas the thoracic region is kyphotic. These sagittal curvatures in conjunction with the intervertebral discs, provides resiliency to applied loads.
Vertebrae are comprised of a thin cortical bony shell surrounding trabecular cancellous bone.
The wedged shape of the thoracic vertebrae is responsible for normal thoracic kyphosis.
The lumbar vertebrae are rectangular in shape. Thus it is the intervertebral discs that are responsible for normal lumbar lordosis. Loss of disc height as a result of disc degeneration results in loss of the normal lumbar lordosis and, subsequently, loss of resiliency to axial load.
The vertebrae increase in size as one moves caudally as they become progressively more involved in load bearing.
The sacrum forms the base of the spinal column and also functions as the keystone of the pelvic ring, transferring load from the spinal column to the lower extremities.
Each vertebra has a bony ring posteriorly that contributes to the anatomy of the spinal canal, as well as multiple processes that serve as lever arms for the ligamentous and muscular attachments (e.g., spinous process, transverse process).
The intervertebral foramina are the lateral openings between adjacent pedicles through which the spinal nerves exit the spinal canal.
The thoracic spine is inherently more stable than the cervical and lumbar spines due to the stabilizing effects of the rib cage and sternum.
The thoracolumbar junction is a transition zone between the relatively rigid thoracic spine and the relatively flexible lumbar segments and thus is at higher risk for injury.
Articular Anatomy
The posterior zygapophyseal/facet joints are additional paired linkages that, with the intervertebral disc, are responsible for controlled intersegmental motion of the vertebral bodies.
Facet joint orientation plays a role in directing allowable spinal motion. In the thoracic spine where the facet joints are more coronally oriented, rotation is the predominant allowable motion. In the upper lumbar spine where the facet joints are more sagittally oriented, flexion and extension predominate. Finally, at the thoracolumbar and lumbosacral transition zones, the transitioning orientation of the facet joints (coronal to sagittal at the thoracolumbar junction and sagittal to coronal at the lumbosacral junction) allow for limited multiplanar motion.
Because of the lumbar facet joints’ dorsolateral relationship to the thecal sac and nerve roots, they can contribute to root compression (in conjunction with disc protrusion), classically in degenerative lumbar stenosis associated with facet joint hypertrophy.
The costovertebral joints are synovial joints located between the vertebral bodies and the ribs.
The costotransverse joints are also synovial joints located between the rib and the transverse processes of the vertebra of the same level.
The costochondral joints are articulations that lie between the rib and its connection with the sternum.
Intervertebral Disc Anatomy
The outer portion of the disc is the annulus fibrosis, composed of concentric rings of fibrocartilaginous tissue.
The inner portion of the disc is the nucleus pulposus, gelatinous material consisting of loose, randomly oriented collagen embedded in a matrix of glycosaminoglycans, water, and salt.
With age, the amount of water within the disc decreases, and therefore, the height of the disc decreases.
The vertebral endplates are composed of hyaline cartilage.
The blood supply to the disc is obliterated within the first three decades of life. Thereafter, the discs must rely on diffusion from the endplate and the annulus for nutrition.
Musculoligamentous Anatomy
The vertebral motion segments are stabilized by the strong anterior longitudinal ligament (ALL) ventral to the vertebral bodies, the weaker posterior longitudinal ligament (PLL) dorsal to the vertebral bodies, and the posterior ligamentous complex (PLC).
The anatomic structures of the PLC include the supraspinous ligament, interspinous ligament, ligamentum flavum, and facet joint capsules. The PLC plays a critical role in protecting the spine and spinal cord against excessive flexion, rotation, translation, and distraction. Some have likened it to a posterior tension band that restricts excessive motion. If disrupted, the ligamentous structures demonstrate poor healing ability, which often results in the need for stabilization of the involved vertebrae to prevent progressive kyphotic collapse.
Because of narrowing of the PLL, the lumbar region tends to be more susceptible to disc herniations because there is an inherent weakness in the posterolateral aspect of the intervertebral disc.
The ligamentum flavum lies dorsal to the thecal sac between the lamina. It is continuous with the anterior capsule of the zygapophyseal joint and helps to resist flexion. With loss of disc height, the ligamentum flavum can buckle into the spinal canal, resulting in neural compression.
The back muscles are innervated by dorsal rami of the spinal nerve roots and are divided into layers.
Superficial layer: trapezius, latissimus dorsi, and lumbodorsal fascia.
Superficial middle layer: levator scapulae, and the major and minor rhomboids.
Deep middle layer: erector spinae muscle group consisting of the spinalis, semispinalis, longissimus, and iliocostalis.
Deep layer: multifidi, rotatores, and intertransversarii.
Nervous System
The ventral and dorsal spinal nerve roots exit the spinal canal via the intervertebral foramen, form the spinal nerve proper, and then divide into the ventral and dorsal rami.
The ventral rami form the lumbosacral plexus innervating the lower extremity musculature.
The dorsal rami form the cutaneous and muscular innervation to the back, erector spinae, fascia, ligaments, and facet joints.
The sinuvertebral nerve, a branch originating distal to the dorsal root ganglion, supplies the PLL, posterior annulus, and posterior vertebral body. It is thought to be one of the nerves responsible for conveying signals responsible for the experience of back pain.
In the thoracic spine, the nerve root passes through the center of the foramen.
In the lumbar spine, the nerve root hugs the inferior border of the pedicle. Thus, posterolateral disc herniations do not compress the exiting root because it has already exited the foramen. Involvement of the traversing root is more typical (i.e., a posterolateral L5-S1 disc herniation tends to affect the S1 nerve root since the L5 nerve root has already exited the spinal canal through the foramen, cranial to the L5-S1 disc protrusion.)
INITIAL EVALUATION
On the field management of the injured athlete with suspected spinal trauma is discussed more comprehensively elsewhere in this text. Briefly, when a spine injury occurs during sports, the primary goal is to prevent additional damage (11). One should have a high index of suspicion for
unstable spinal injuries when an appropriate mechanism for injury exists. Patients with acute complaints of severe neck or back pain, patients with neurologic symptoms, and all unconscious patients should be treated as if they have an unstable spinal injury until proven otherwise. Early recognition and institution of appropriate management protocols for spinal trauma by emergency medical services have resulted in improved outcomes in spine-injured patients. These same algorithms should be used for the injured athlete.
Table 45.1 Historical Information to Obtain When Evaluating a Patient with Low Back Pain
General health of the patient aids risk-benefit analysis of treatment options
▪
Age
▪
Comorbidities
Sport activity level of the patient aids return-to-play decision making
▪
Recreational vs. competitive vs. professional athlete
Mechanism of injury suggests diagnosis and treatment options (activity modification)
▪
Repetitive injury vs. acute injury
▪
Blunt trauma
▪
Axial load
▪
Hyperflexion
▪
Hyperextension
▪
Rotation
Location of symptoms can aid in diagnosis
▪
Back – spinal vs. musculoligamentous
▪
Buttocks – spinal vs. sacroiliac vs. tendinitis/bursitis (e.g., at the ischial tuberosity)
▪
Groin – hip joint vs. spinal
▪
Hips – spinal vs. trochanteric pain syndromes
▪
Radiating leg pain that does not go past the knee – spinal vs. sacroiliac
▪
Radiating leg pain past the knee – radicular pain
Severity of symptoms aids selection of treatment options
Neurologic symptoms narrow differential to spinal, plexus, or peripheral nerve involvement
▪
Anesthesia
▪
Paresthesia
▪
Dysesthesia
▪
Weakness
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
Get Clinical Tree app for offline access
