Basic Mechanics

The spine is made of 33 bones, which increase in size caudally. There are five regions including cervical, thoracic, lumbar, sacral, and coccyx. Components of the axial skeleton include osseous (bony) and nonosseous structures. Osseous structures include the vertebrae, and nonosseous structures are the intervertebral discs and the surrounding ligaments. Together these make up the normal spinal curves that define posture. These curves function to absorb shock and balance the center of gravity. The typical spinal vertebra has two portions: the body, which assists in weight bearing, and the vertebral arch, which protects the spinal cord. Also there are facet joints, or zygapophyseal joints, which guide range of motion (ROM) in the spine. These joints are plane joints, which glide relative to one another. The inferior aspect of the superior facet joint articulates with the superior aspect of the inferior facet joint. ROM is determined by the orientation of the facet joint. For example, in the cervical spine the facet joints are more horizontal in alignment, which allows for increased rotation. In the lumbar spine the joints have a vertical orientation, which allows for flexion and extension.

In the adult spine there are 23 intervertebral discs found in between the vertebral bodies (Fig. 20-2). The outer wall of the disc is called the annulus and comprises 12 to 18 concentrically arranged rings of fibroelastic cartilage.^30,56 Contained within the annulus is the nucleus pulposus. Nuclear material is a mucopolysaccharide gel³⁰ that transmits forces, equalizes stress, and promotes movement.⁵⁵ The annulus provides stability, enhanced movement between vertebral bodies, and minimal shock absorption. The greater portion of shock absorption comes from the vertebral body.^56,65

The intervertebral disc is largely avascular and aneural. The vascular supply to the disc is provided by diffusion from the vertebral bodies above and below the disc.14,30,49,56 The outer one third of the annulus is said to be innervated along with the facet joint capsule and exiting nerve roots.¹⁴ When injured, without an intense vascular response, the disc has a limited capacity to heal and repair. In addition, degenerative changes also occur within the disc as a normal process of aging throughout the life span.

A popular theoretical model describes the fluid mechanics of the disc (nucleus pulposus) influenced by the motion of the lumbar vertebral segments. McKenzie⁴⁹ describes flexion and extension motion of the spine as having clinically significant effects on the nucleus’s direction of movement (Fig. 20-3, A). The theoretical model proposes when positional changes occur in the lumbar spine, from flexion to extension, the nucleus moves anteriorly (Fig. 20-3, B).⁴⁹ Conversely, when the spine moves from extension to full flexion, the nucleus tends to displace or move posteriorly (Fig. 20-3, C). Thus it is necessary to fully understand the individual nature of each injury and avoid or enhance certain motions and postures as directed by the physical therapist (PT).

The amount of motion in the spine is primarily determined by the size of the vertebral body and the disc. Ligaments, fascia and musculature assist in restricting certain movements. The direction of motion is determined by the orientation of the facets. Spinal motions include flexion, extension, lateral flexion (side bending), and rotation.

The lumbar spine is composed of five anterior convex and posterior concave segments that produce the recognizable lordotic curve. Normal lordosis is increased with spinal extension and reduced with spinal flexion. The lumbar spine serves to support the weight of the upper body and dissipate compressive loads with minimal production of muscular torque. As a result significant forces are transmitted through the intervertebral disc during certain motions. Allman¹ describes lumbar motion and postural alterations as producing significant pressure within the disc (intradiscal pressure). The compressive forces that influence intradiscal pressure are as follows¹:

Intradiscal pressure also can be expressed in terms of pressure or load measured within the intervertebral lumbar disc. Cailliet⁹ reports that isometric abdominal sets produce approximately 110 kg of pressure within the disc, whereas walking produces 85 kg; sitting, 100 kg; bilateral straight-leg raises in supine position, 120 kg; and lifting with a flexed torso and knees held straight, an astounding 340 kg of intradiscal pressure. This information may help clarify the rationale for protective postures, lifting protocols, and appropriate body mechanics, as well as prescribed exercises for specific lumbar spine conditions.

The PTA is strongly encouraged to thoroughly review the anatomic relationships among the lumbar vertebral bodies, discs, spinal canal, and nerve roots.

Lumbar Intervertebral Disc Pathologies

Various terms are used to describe injuries to the disc. Although “slipped disc” is a common expression used to describe various ailments of the low back among the general population, a disc does not “slip” from within its confines between the vertebral bodies. Also incorrectly applied are the two terms, disc bulge and herniated nucleus pulposus (HNP). These are frequently used interchangeably. To clarify, a HNP can be defined by specific nomenclature to more precisely describe the injury. Miller⁵¹ describes the three categories of HNP as protruded, extruded, and sequestrated. In a disc protrusion, the nucleus bulges against an intact annulus (Fig. 20-4, A). This would more closely resemble the layperson’s disc bulge terminology. An extruded disc is characterized by the nucleus extending through the annulus, but the nuclear material remains confined by the posterior longitudinal ligament (Fig. 20-4, B). Finally, in a sequestrated disc, the nucleus is free within the canal (Fig. 20-4, C).

Macnab⁴⁶ offers a variation of this classification model:

Thus in a disc protrusion the annular fibers are intact, although the annulus bulges. A prolapsed disc has the nucleus contained only by the outer fibers of the bulging annulus.

Regardless of the exact nature of the injury, a HNP remains primarily a disease of young to middle-aged adults.⁵¹ Common age-related degenerative changes that occur within the disc include decreased hydration, with a decreased water content from 70% to 88% by the third decade; biochemical changes in the glycosaminoglycans of the nucleus; and increases in collagen. As a result these changes make disc herniations rare in elderly people.^51,56

When examining a patient who exhibits radicular signs, the PT confirms or denies the presence of peripheralization or centralization phenomena by observing a directional preference.41,49 These conditions identified during the initial examination are defined by Kisner and Colby⁴¹ as follows: “When repeating the forward-bending test, the symptoms increase or peripheralize. Peripheralization means the symptoms are experienced further down the leg.” Centralization is defined by McKenzie⁴⁹ as, “the phenomenon whereby, as a result of the performance of certain repeated movements or the adoption of certain positions, radiating pain originating from the spine and referred distally, is made to move away from the periphery and toward the mid-line of the spine” (Fig. 20-5). The evaluation data obtained by the PT regarding the presence of a directional preference is essential in determining treatment.

Spondylolysis and Spondylolisthesis

Spondylolysis is a bony defect (stress fracture or fracture) in the pars interarticularis of the posterior elements of the spine (Fig. 20-6, A).^{8,9,15,21,51,56,62} Spondylolisthesis, on the other hand, describes a forward slippage of one superior vertebra over an inferior vertebra (usually L4-L5 and L5-S1)^18,21 as a result of instability caused by the bilateral defect in the pars interarticularis (Fig. 20-6, B).^{8,9,15,21,51,56,62} There are specific classification types, as well as degrees of slippage or “migration” of the vertebrae in the disease process of spondylolisthesis.²¹ Five types, or classifications, have been identified, as follows^8,21,51:

 Type I: Congenital or dysplastic. Results from a “congenital malformation of the sacrum or neural arch of L5, which allows forward slippage of L5 on the sacrum.”⁸ Most common in children.

 Type II: Isthmic spondylolisthesis. The most common type, affecting persons 5 to 50 years of age.⁵¹ Usually a result of mechanical stress that causes a stress fracture at the pars interarticularis.^21,51

 Type III: Degenerative spondylolisthesis. Most commonly affects the older population. Characterized by a loss of ligament integrity (or stability) that results in forward slippage of the vertebrae. Generally associated with the normal aging process.⁸

 Type IV: Traumatic spondylolisthesis. Caused by trauma that produces an acute fracture of the pars interarticularis. Casting is the most appropriate form of treatment.⁸ Because of their generally high levels of physical activity, this type usually affects young patients.⁵¹

 Type V: Pathologic spondylolisthesis. Characterized by bone tumors that affect the pars interarticularis.

The degree or grade of slippage is determined radiographically by the examining physician and is defined as the amount of forward displacement of the superior vertebrae over the inferior vertebrae, as outlined in the following:8,15,51

 Grade I: 0 to 25%

 Grade II: 25% to 50%

 Grade III: 50% to 75%

 Grade IV: 75% to 100%

The cause of the defect in the pars interarticularis is in part a congenital weakness in this area. In addition, the pars interarticularis is subjected to high levels of mechanical stress.64,65 Authorities also suggest that the primary initial cause of the most common type of spondylolisthesis (isthmic) is fatigue fracture of the pars interarticularis.⁶⁵

Patients primarily report pain with extremes of lumbar motion, especially extension. The pain generally follows the belt line.³⁷ During examination, the PT also may identify a palpable step-off between the affected lumbar vertebrae (usually L4-L5) because of the forward slippage.¹⁵

The management of spondylolisthesis is dictated by symptoms, as well as the degree of vertebral slippage (grades I to IV). For example, an adult with isthmic spondylolisthesis of radiographically determined grade I (0 to 25% slippage) may not experience significant symptoms with activity or extremes of lumbar extension. Thus treatment is aimed at preventing any progression to grade II (25% to 50% slippage). This usually is accomplished by instructing the patient to avoid ballistic lumbar extension, as well as vertical loading while seated or standing, so as to minimize anteriorly directed shearing forces on the spine. In addition, abdominal strengthening exercises, neutral spine stabilization exercises (controlled lumbar extension strengthening, isometrics, and rectus and oblique abdominal strengthening while in the neutral spine position), and stretching exercises for the trunk and lower extremities are encouraged.

The patient may require more specific attention when there is a greater degree of slippage with significant symptoms. Generally, pain and muscle spasm are addressed with physician-prescribed analgesics, muscle relaxants, nonsteroidal antiinflammatory drugs (NSAIDs), and agents (heat, ice, ultrasound, and electrical stimulation) to alleviate acute pain and swelling. If the pain is related to a fatigue fracture of the pars interarticularis, initial treatment focuses on managing stress to the fracture site using a lumbosacral corset or orthosis, which reduces anterior shearing forces through the fracture site and allows for bone healing.21,37

The cornerstone in the care of spondylolisthesis is application of abdominal and paravertebral muscle strengthening exercises to provide dynamic support for the spine during activity and avoidance of extreme lumbar extension. A young active patient must modify activities that directly influence the course of this disease. For example, weight lifting without proper precaution can contribute significantly to the occurrence of spondylolysis.¹⁹

Surgery is rare and usually is reserved for patients with radicular symptoms and high-grade slippage (grades III or IV), which compresses the nerve roots and causes neurologic signs.8,51 The type of surgery advocated in these cases is a decompression laminectomy (to reduce compression of the nerve roots) with fusion to stabilize the vertebral segments.^8,51

Rehabilitation after surgery for spondylolisthesis is deferred until solid bony union is determined radiographically. The patient is usually in a lumbosacral orthosis that does not permit lumbar extension. During immobilization, the patient can ambulate as tolerated and perform rudimentary ROM and strengthening exercises for the upper and lower extremities (ankle pumps, quadriceps sets, and knee ROM). Once bone healing is confirmed, a gradually progressive program of abdominal strengthening (from isometrics to concentric and eccentric abdominal contractions), lumbar ROM (avoiding dynamic, ballistic, and extreme lumbar extension), general conditioning, and a progressive return to function is advocated.8,51

Spinal Stenosis

Lumbar spinal stenosis is defined as a narrowing of the spinal canal, which constricts and compresses nerve roots (Fig. 20-7).⁵¹ This gives rise to symptoms of neurogenic or spinal claudication, as follows:

1. Radicular ache into the thigh and less frequently into the calf⁸

2. Paresthesias into the lower extremity²⁹

3. Disturbances in motor function²⁹

This condition occurs in males “twice as often as females”⁵¹ and typically is observed during late middle age and older.^29,51

Lumbar spinal stenosis is most commonly acquired as a result of degenerative arthritic changes that encroach on the diameter of the canal, producing nerve root compression.⁵¹ The patient with stenosis frequently complains of pain and increased symptoms with lumbar extension. Extension of the lumbar spine in a patient with stenosis further compresses the spinal canal, thereby increasing pain and paresthesias.^15,29,51

During ambulation and gait training, an elderly patient typically demonstrates a forward-flexed trunk posture when using a walker. Under careful observation and questioning, the patient may suggest that leaning forward feels better and reduces back and leg pain. The role of the PTA is to continually educate the patient, reinforcing appropriate postures, body mechanics, and lifting techniques. Sitting and sleeping changes, as well as a general physical conditioning and weight management programs are also addressed and have been identified as an important adjunct in the overall management of patients with spinal stenosis.⁵¹ Whitman and colleagues⁶³ demonstrated that subjects with spinal stenosis experienced greater improvements in pain and recovery at 6 weeks with manual therapy, exercise, and walking than subjects who just performed routine flexion exercises and walking. The physical therapy team should work together to provide the appropriate manual intervention followed by specific exercise and a walking program for the best management of patients with spinal stenosis.

Lumbar Spine Fractures

Fractures of the lumbar vertebrae generally occur after a profound traumatic event and can be classified according to the forces that produce the fracture. For example, compression, flexion, extension, flexion-distraction, flexion-rotation, and lateral flexion are forces that produce fractures.⁵¹ Lumbar spine fractures also can be described in terms that graphically depict a specific fracture deformity, including crush, wedge, burst, shear, slice, and teardrop fractures.⁵¹

Perhaps the most clinically relevant spine fracture for the PTA to consider is the vertebral compression fracture. Vertebral compression fractures are the most common osteoporosis-related spinal fracture with approximately 700,000 occurring per year, and the prevalence of vertebral compression fractures increases with age.15,29,43

Many benign activities can produce compression fractures in an elderly population of patients with osteoporosis.8,43 Care must be taken to ensure that no rapid deceleration occurs when an elderly patient transfers to a bedside commode or any other hard surface. This seemingly trivial activity frequently causes multilevel compression fractures in patients with osteoporosis. Compression fractures produce symptoms ranging from acute local pain to essentially no signs at all.⁴³ Thus subtle complaints of pain caused by typical daily activities, such as bending, lifting, or rising from a chair, must be viewed with a high level of suspicion in elderly patients.⁴³

Treatment of compression fractures focuses on relief of pain; authorities29,43 advocate activity modification, physician-prescribed analgesics, NSAIDs, heat, ice, massage, and electrical stimulation to control pain, swelling, and associated muscle spasm. During the acute and subacute phases of recovery, the patient with compression fractures must avoid thoracic or lumbar flexion activities.²⁹ Repeated trunk flexion is contraindicated because it creates an anterior wedging of the vertebral bodies, producing greater stress and compression at the fracture site.²⁹Appropriate exercise progression should target the muscles supporting or attached to the affected bone, and they will be determined by the PT. Exercises should be combined with postural correction, scapular stabilization, and improving weight-bearing patterns, strength, balance, and flexibility.

Compression fracture prevention education programs, especially in patients with osteoporosis, should focus on implementing an exercise program designed to increase strength, flexibility, and bone density, as well as improve balance, posture, and body mechanics to help maintain bone mass. Other preventative measures include identifying potential hazards in the home, selecting appropriate assistive devices, and general patient education.

Treatment-Based Classification

Rehabilitation of the lumbar spine is focused toward impairments rather than labeling pathoanatomic findings. As a result, when a patient experiences low back pain, the evaluating PT assimilates information from the patient history, examination, and current best evidence, and classifies the patient into the most appropriate category. The rehabilitation plan will include a multimodal approach that categorizes patients based on their overall symptomatology and response to a specific intervention. This system has been identified as treatment-based classification (TBC).⁶

The TBC system consists of subgroupings through which the patient moves fluidly in and out of during the course of care. The interventions within these categories include manual therapy and exercise,12,22 specific exercise for directional preference,^7,63 traction,^24,25 neuromuscular reeducation and stabilization exercise,^34,52,54 aerobic exercise, and recommendations to stay active. PTs will use their findings from the clinical examination to match the patient with the most appropriate intervention. Research has shown patients managed with this systematic approach experience significant decreases in pain and disability.^6,24 For the PTA it is important to be aware of the categories along with exercise and educational concerns within each.

Some patients with acute or chronic low back pain will benefit from first restoring mobility in the spine, and therefore these patients will initially be placed in the manual therapy and exercise category. The PT will address any segments that need to be mobilized before initiating an exercise program for the patient. Early exercises are chosen to enhance the restoration of normal movement in the lumbar spine and include pelvic rocking and abdominal bracing. Patients with short duration of symptoms (less than 2 or 3 weeks), no symptoms distal to the knee, and low fear-avoidance behaviors are expected to experience a 50% reduction in disability in 1 to 2 weeks on the Oswestry Disability Index (ODI)Questionnaire.12,22 However the PT may choose to progress the patient gradually based on the presence of elevated fear avoidance beliefs noted on the Fear Avoidance Beliefs Questionnaire (FABQ).²⁸

Patients with more chronic or recurring symptoms of low back pain are managed with neuromuscular reeducation and stabilization exercise. These patients often present with an average straight leg raise greater than 91° and the presence of aberrant motions. Exercises focus on recruitment and control of the multifidi, transversus abdominis, internal and external obliques, and the gluteal musculature. With this strategy, patients can also expected to achieve a 50% reduction in disability on the ODI in 8 weeks.³⁴

In the presence of a directional preference, the patient experiences a centralization phenomenon where distal lower extremity symptoms and low back pain are lessened with repeated movements into a particular direction. The symptoms become more centrally located with certain motions. An example of a repeated movement or prone progression is shown in Figure 20-8. Research has shown the adoption of the appropriate exercise program based on the patient’s directional preference will allow for less pain and disability for up to 6 months.⁷ Occasionally patients with distal lower extremity symptoms and neurologic signs will not demonstrate centralization with movement testing. In which case, the patient may benefit from mechanical traction in addition to specific exercises.²⁴

The PTA should be extremely cognizant of any new reports of changes or worsening in patients’ signs and symptoms and report these findings immediately to the evaluating PT. Some changes may include worsening or peripheralization of symptoms into the lower extremity, the presence of night pain, changes in bowel or bladder activity, or saddle anesthesia.

Invasive Management

When conservative physical therapy (including active rest, medications, exercise, and postural correction) fails to bring significant relief from symptoms, the physician may offer several invasive procedures. For some patients whose persistent radicular pain (sciatica) cannot be controlled by conservative measures, the physician may prescribe an epidural steroid injection to relieve symptoms.21,51 These injections are given only to relieve pain and reduce inflammation, and are not intended as a curative procedure to correct any neurologic deficits.

Patients may undergo surgery in the presence of a large disc herniation. As described by Miller⁵¹ and Eismont and Kitchel,²¹ the most common procedure is a laminotomy with a decompression discectomy. In this procedure the physician gains exposure to the herniated disc by cutting into the lamina and then removing all nonviable disc material, thereby decompressing the affected nerve root (Fig. 20-9). While some patients report good or excellent results with this particular surgical procedure, as many as 30% of these patients may have significant back pain at long-term follow-up.^18,51 Other invasive procedures exist, such as microsurgical discectomy and automated percutaneous discectomy.

Rehabilitation after any surgical procedure is highly patient-specific and directly related to the data obtained at the initial postoperative physical therapy evaluation. Generally, recovery closely parallels the criteria established with conservative management including neuromuscular re-education and stabilization exercise. However, extensive surgical exposure is necessary to perform a laminotomy with discectomy, and tissue-healing constraints influence recovery.

After surgery, the patient is taught bed mobility and transfer training using the log-roll technique to move from a supine to sitting position. Ambulation with a walker or crutches is generally allowed 1 day after surgery. Ambulation distance and endurance activities are increased according to each patient’s ability. Rudimentary bed exercises can be performed the day after surgery and include active ankle pumps, gentle hip and knee flexion, and isometric exercises (quadriceps and gluteals). The PT guides the PTA concerning whether the postoperative patient will perform any isometric exercises. The PTA must instruct the patient in and reinforce proper breathing techniques if isometric exercises are done. The Valsalva maneuver is strictly avoided during all exercises.

For the first 3 days after surgery the patient is limited to sitting for no more than 1 hour at a time and must maintain proper spinal position with no flexion.¹⁰ The PTA continually reinforces and encourages proper posture during the first week of recovery. The patient should be cautioned to avoid forward bending and trunk rotation.

More demanding and functionally relevant activities that do not stress the surgical site are added gradually. Transfers from supine to sitting and from sitting to standing must be demonstrated by the patient and observed by the clinician to be safe, efficient, and free from all unwanted stress. Throughout the first week, exercises can progress to include functional closed-chain activities while maintaining proper neutral spine positioning.

When initial wound healing is complete and pain is decreased, a more accelerated program of strengthening can begin. ROM is encouraged gradually as soon as the patient can tolerate these motions. Gentle active extension exercises and pelvic tilts (which promote pelvic motion, control, as well as limited-motion lumbar spine flexion and extension) begin early in the recovery phase.

The patient must achieve increased motion, controlled pain, improved endurance, and sufficient strength before beginning a general conditioning program after surgery. The longer recovery period is needed to allow for proper soft-tissue healing, bone healing, and control of inflammation and pain before subjecting the affected area to stress. From 3 to 5 weeks after surgery, the goals of recovery are identified as restored lumbar motion, normalized upper and lower extremity strength, improved aerobic fitness, and decreased pain and swelling.¹⁰

Progressive functional exercises can be added as the patient achieves these criteria. These include treadmill walking, balance activities, isotonic strengthening exercises, general flexibility exercises, and cardiovascular conditioning (via upper body ergometer, recumbent cycle ergometer, treadmill, stair-stepper, and cross-country ski machine).

Fundamental Mechanics of Lifting

Forces and stresses related to lifting, sitting, standing, walking, sleeping, and twisting are common to all activities of daily living (ADLs). O’Sullivan and colleagues⁵³ have identified a novel concept to instruct patients in proper lifting mechanics, listing the “five Ls” of lifting: load, lever, lordosis, legs, and lungs.

The load to be lifted is central to all concepts of lifting mechanics. The amount of weight to be hoisted should be appropriate for the task and for the individual attempting to lift it. The lever refers to keeping the object as close to the body as is functionally possible throughout the lift. If the object is held away from the body, the increased force (both intradiscal pressure and muscle strain) may strain the lumbar spine. Lordosis refers to maintaining a normal anatomic lordotic curve while lifting any object. Teaching the patient (and the PTA) to lift with the legs is basic to all lifting procedures. The muscles of the legs should be conditioned to fully participate during the lifting of any object from the floor. If the legs are not used fully, the muscles of the back may be necessary to absorb increased stress. The lungs refer to the use of proper breathing techniques during lifting. The Valsalva maneuver (closed glottis during attempted expiration) should be avoided and instruction given on exhaling during the actual lift.

Kaiser and co-workers^40a have identified a lumbar stabilization model comparing two lumbar spine postures during lifting. In the first posture (tested electromyographically) the starting position is characterized by a posterior pelvic tilt. The abdominal muscles are in a shortened position, the lumbar paravertebral muscles show no electromyographic activity, the posterior ligaments and posterior annular wall are stretched, the knees are in a position of decreased leverage, and the patient’s center of gravity is posterior to the base of support (Fig. 20-10, A).¹⁴ In the second posture, the patient’s lumbar lordosis is maintained during the lift. The abdominal muscles are in their normal anatomic length, the paravertebral muscles contracted, the posterior ligaments relaxed, the knees in an optimal leverage position, and the patient’s center of gravity over the base of support (Fig. 20-10, B).

Prevention and Education for Back Dysfunction: The Back School Model

Although understanding and managing low back dysfunction is the focus of this section, prevention of lumbar spine injuries also is pertinent to this discussion, because the PTA is frequently directed to participate in and to carry out community-based back injury prevention programs under the supervision and direction of a PT. These education programs are commonly referred to as back schools and are designed to provide an understanding of anatomy, causes of back pain, lifting mechanics, posture, self-care for back pain, exercise, nutrition (weight management), ergonomics (which involves lifting, posture, general body mechanics, job modifications, and work site protection and redesign to minimize back injury), and stress reduction for high-risk patients and the population at large.

Often patients with a history of back pain are identified as ideal candidates to participate in these programs. Also, persons at risk (identified by job responsibilities, repetitive lifting, overweight condition, poor posture, poor body mechanics, relative weakness, and poor general physical conditioning) may be referred to these programs.

Many back schools involve a 1- or 2-hour class (consisting of lectures, slides, demonstration, and participation) each week for 4 to 6 weeks. Each session or class builds on the previous lecture to convey the principles seen in spinal anatomy, causes of back dysfunction, risk factors, posture, body mechanics, and treatment approaches.¹ Back schools can be based in outpatient physical therapy clinics, hospitals, industrial health clinics, wellness programs at work, or community fitness centers. In every case, the program should be under the direction and supervision of a PT, physician, or both.

Allman¹ has identified the outline in Table 20-1 as an appropriate general back school program. The curriculum clarifies the rudimentary concepts of education and prevention for a wide variety of back-related problems. The PTA who presents this information must be given specific information, evaluation data, indications, and contraindications for each patient participating in the back school program. In this way all phases of recovery and prevention can be individualized for each patient.

Thoracic Disc Injuries

Thoracic disc herniations are rare (less than 0.3% of the population) and affect both men and women equally from the fourth through the sixth decades of life.⁸ The most common segments affected are between the ninth and twelfth thoracic vertebrae.⁸

The type of treatment employed for thoracic disc herniations depends on whether the disc is herniated laterally or centrally.8,21 A large central disc prolapse may produce symptoms of “spastic paraparesis, increased deep tendon reflexes, and a positive Babinski response.”²¹ However, lateral thoracic disc protrusions can produce signs more consistent with nerve root compression.

The PTA is exposed to both conservative care and postsurgical recovery after thoracic spine disc herniations. Less severe lateral disc herniations can be treated effectively with periods of active rest, analgesics, modalities to control pain and swelling, and epidural injections. More severe central disc herniations, involving progressive neurologic deficits, must be treated surgically to decompress the neurologic impingement.8,21 Recovery after thoracic decompression closely follows the time necessary for healing of bone and soft tissue with extensive periods of supportive bracing to protect the affected spine from unwanted forces, and a progressive regimen of active motion, strengthening, and endurance activities, and a return to function with specific limitations delineated within the protocol developed by the surgeon and PT.

Kyphosis

Kyphosis is defined as an increase in the thoracic posterior convexity that is manifested by a rounded-back (and protracted scapulae) posture. Kyphosis can be subdivided into congenital, neuromuscular, and postural categories.²¹ Osteoporosis, which can lead to multilevel thoracic compression fractures, causes anterior wedging of the involved segments and creates the kyphotic curvature.

The causes of pain associated with an increased thoracic convexity have been identified as stress originating from the posterior longitudinal ligaments, muscle fatigue resulting from stretched and weakened erector spinae and rhomboid muscle groups, and various postural and neurologic syndromes.⁴¹

The treatment of kyphosis depends on the degree of curvature, which is determined radiographically by the treating physician, any associated disc involvement, and the severity of symptoms.⁵ In advanced cases of postural kyphosis with profound curvature and significant symptoms, the patient may require supportive bracing of the thorax to minimize the compression associated with anterior wedging of the vertebral bodies. With less severe kyphosis, the PTA plays a critical role in patient education, postural awareness, and the application of specific exercises to simultaneously stretch the anterior shoulder and pectorals and strengthen the thoracic extension muscles.

To effectively strengthen the scapular retractors, rhomboids, middle trapezius, and erector spinae of the thoracic region, a sufficient degree of freedom of movement in these areas is needed. Generally the anterior shoulder muscles and pectorals are shortened and relatively weak in response to the increased thoracic convexity. Therefore to provide the needed stimulus for full ROM strengthening, the anterior aspect of the thorax also must be addressed. Stretching the anterior shoulder muscles can be done both actively by the patient and passively, where the clinician provides the stretching. An effective active assisted stretch can be performed with the patient facing the corner of a room or standing in an open doorway. Both of the patient’s hands are placed in a comfortable position on either side of the doorway. Then the patient slowly leans forward, providing a slow, static stretch to the pectorals and anterior shoulder. This position can be held for a prolonged stretch and usually is performed for multiple sets.

A passive stretch also can be employed with the patient in a seated position. With both of the patient’s hands placed behind his or her head, the PTA stands behind the patient and grasps both elbows. The PTA delivers a slow posteriorly directed stretch to the pectorals and anterior shoulder muscles. To be effective, stretching must be performed consistently each day. Therefore the patient must perform stretches two or three times daily as part of a home exercise program. In addition to stretching the thorax, posterior thoracic strengthening must be addressed. The patient performs seated active scapular retraction exercises with an emphasis on maintaining an isometric contraction, or set, of the scapular muscles with each repetition.

As described, the patient does the three-progression prone thoracic extension exercises. In addition, the patient performs scapular adduction while lying prone with both arms held straight at 90°. Both arms are elevated while adducting the scapulae and holding the contracted position isometrically for 10 seconds.⁴¹ This position can be modified slightly by having the patient hold weights while performing scapular adduction with both elbows flexed, creating more of a prone rowing motion.

The patient must perform both stretching and strengthening exercises daily as part of a home program. As the patient’s motion improves and where posterior scapular strength increases, isotonic resistance exercises should be encouraged to a greater degree to provide increased stimulus for strengthening. In the home program, latex tubing or Thera-Band can be used in a seated rowing position to enhance scapular adduction. Commercially available isotonic rowing machines effectively provide greater resistance for the scapular muscles.

When treating postural kyphosis, the home exercise program must be carried out faithfully and the patient must develop an acute postural awareness at home and work. If the patient performs tasks at work that contribute to a rounded-shoulder position, modifications of these tasks is necessary. In many cases, the cause of poor thoracic posture is an inefficient work station arrangement in which the patient must maintain poor posture to perform tasks such as typing, writing, assembly work, or computer data entry. A simple adjustment in the height of the workstation so that it is closer to and centered midline with the patient encourages a more erect thoracic spine. Therefore the total care of the patient focuses on symptomatic pain relief using physician-prescribed analgesics, thermal agents, massage, and a comprehensive program of stretching, strengthening, education, and work site modifications.

Scoliosis

Scoliosis can be identified as any lateral curvature of the cervical, thoracic, or lumbar spine.⁴¹ Scoliosis usually is idiopathic (cause unknown), but it also can result from neuromuscular causes or can be related to degenerative disease, osteoporosis, trauma, and postsurgical factors.⁵¹ Kisner and Colby⁴¹ identify the incidence of idiopathic scoliosis as being as high as 75% to 85% of all recognized types of scoliosis. Generally scoliosis can be recognized as either structural or nonstructural.⁴¹

Structural scoliosis is defined as an “irreversible lateral curve of the spine with fixed rotation of the vertebrae.”⁴¹ During the PT’s initial evaluation of structural scoliosis, the clinician will observe whether the identified lateral curve decreases with forward trunk flexion. If not, structural idiopathic scoliosis is not corrected by changes in the patient’s position or during active voluntary activities.⁴¹ Nonstructural scoliosis is classified as reversible, wherein the lateral curve dissipates with positional changes. In either case, pain is the foremost presenting feature of scoliosis,⁵¹ although cosmesis is a great concern. Other complaints involve decreased cardiopulmonary function (usually with thoracic curves greater than 65°) and neurologic symptoms associated with spinal stenosis.⁵¹

The nonoperative management of idiopathic scoliosis primarily involves the assistant in instructing the patient about therapeutic exercises outlined and prescribed by the PT. Scoliosis treatment involves both stretching and strengthening, much like kyphosis. Exercise by itself does not halt the progression or correct scoliosis.⁴¹ The effective use of therapeutic exercise is intended primarily to improve spinal motion, increase muscle strength, and reduce back pain.⁴¹

In addition to exercises, bracing also has been advocated in the treatment of scoliosis.41,51 However, bracing is intended to halt progression of the curve and not correct cosmetic deformity.⁵¹ Perhaps the most commonly used brace for scoliosis is the Milwaukee brace.^41,51 Generally this brace is worn 23 or 24 hours a day.⁴¹ However, Miller⁵¹ suggests that part-time brace wearing is as effective as the traditional long-term application.

A fundamental principle in managing idiopathic scoliosis is stretching of the tight muscles on the concave side of the curve, while strengthening the muscles on the convex side of the curve. In addition, trunk axial elongation (stretching vertically) is important throughout exercise. As stated in the section on kyphosis, some freedom of motion must be available for strengthening exercises to be effective.

Stretching exercises directed toward the concavity must address all of the spinal muscles. Note that a right thoracic convexity results in a left lower thoracic concavity and associated right lumbar concavity with left lumbar convexity (Fig. 20-12). Strengthening exercises are performed for all of the muscles affected on the convex side of each lateral curve.

Various stretching exercises can be performed in prone, side-lying, or heel-sitting position.⁴¹ While prone, the patient places both hands behind his or her head while tilting the thorax away from the concave side of the curve (Fig. 20-13, A). In another prone stretching exercise, the patient reaches overhead and extends the arm on the concave side, thereby effectively stretching the thoracic concavity (Fig. 20-13, B).

In the heel-sitting position, the patient places both hands forward and flat while emphasizing long-axis stretching. The lateral stretching component of this exercise is accomplished by having the patient slowly stretch both arms laterally away from the concave side of the curve (Fig. 20-14).

Static stretching also can be performed with the patient lying on his or her side. Place a small, soft rolled pillow or towel directly under the apex of the thoracic convex curve and support and stabilize the pelvis. For an advanced progression of side-lying stretching, the patient lies over the apex bolster toward the end of a treatment table (Fig. 20-15).

As alluded to in the preceding, trunk elongation (axial stretching) also is an effective stretching procedure used to treat scoliosis. Standing, the patient faces a wall and attempts to “walk up the wall” with both hands. The patient must reach as high as possible with both hands. A more progressive form of trunk elongation is to have the patient hang by both arms from an overhead bar.

Strengthening the thoracic and lumbar spine toward the convex side focuses on thoracic and lumbar extension strength and specific lateral strengthening maneuvers. Prone thoracic and lumbar spine active exercises were outlined and described in the preceding. These are effective when used early to enhance the strength of the thorax.

Specific lateral strengthening can proceed with the patient in a side-lying position on the concave side of the curve. The PTA should stabilize the trunk, then have the patient lift the trunk up toward the convex side of the curve (Fig. 20-16). This exercise can be viewed as a side-lying sit-up.

While this brief discussion has focused on a few rudimentary stretching and strengthening exercises for mild to moderate idiopathic scoliosis, an outline of surgical procedures to correct severe scoliosis is warranted. Surgery is reserved for severe symptomatic curves: those more than 50° to 60°.⁵¹ With surgery, curves of this magnitude can be improved by approximately 50%.⁴¹ The exact surgery performed depends on many factors. However, a spinal fusion with or without Harrington rod instrumentation⁴¹ is designed to elongate and stabilize the spine and thereby reduce pain and improve appearance.

Physical therapy after spine fusion for advanced, severe scoliosis requires extensive convalescence, the application of a postoperative brace, and limited activity for up to several weeks after surgery, depending upon the protocol designed by the collaborative efforts of the surgeon and PT.⁴¹

Whiplash Associated Disorder: Acute Sprains and Strains

Muscular strains of the cervical spine are common among young athletes and in association with motor vehicle accidents with flexion-extension, lateral flexion, and acceleration-deceleration “whiplash” type injuries.59,67 Numerous impairments, stemming from bony and soft tissue injury, can be classified as whiplash associated disorder (WAD).⁵⁸ The U.S. annual cost associated with WAD is $29 billion.⁶⁶ The muscles that can be involved in cervical strains are the sternocleidomastoid, trapezius, scalenes, erectors, rhomboids, and levator scapulae.⁶⁷ The mechanism of injury producing cervical strains and sprains varies but includes hyperflexion, rotation, and lateral flexion of the head and cervical spine.⁵⁹

Forces usually are great enough with automobile accidents that ligament injuries occur in conjunction with muscle strains. In fact, Stratton and Bryan’s⁵⁹ experimental studies have demonstrated a wide range of tissue damage with hyperextension type automobile injuries:

Similar types of injuries occur with hyperflexion injuries as a result of automobile accidents⁵⁹:

The treatment of traumatic cervical spine sprains and strains is symptomatic during the acute stage of recovery. Patients may present with neck pain and referred upper extremity pain. The treating physician usually prescribes a course of analgesics, NSAIDs, or muscle relaxants; rest; and agents to control pain and swelling (heat, cold, ultrasound, and electrical stimulation). The healing constraints of muscle and ligament tissues differ; both must be addressed throughout recovery.

After the initial pain and swelling are controlled, the patient may be introduced to a series of active ROM exercises, cervical isometric strengthening exercises, and education in cervical posture mechanics. Initial ROM exercises must be approached cautiously to avoid reproducing the motion that caused the injury. As with all soft-tissue injuries, attention must be focused on protection of the affected area while striving to prevent further injury. If, for example, the mechanism of cervical sprain and strain was hyperflexion, care must be directed at avoiding the end range of head and neck flexion. Gentle active ROM exercises can proceed after moist heat application for 20 minutes to enhance muscle relaxation, relieve pain, and stimulate greater mobility.

Full recovery from acute sprains and strains of the cervical spine involves the elimination of pain and swelling initially, appropriate rest from any aggravating positions, protection from unwanted stress, the return of normal cervical spine ROM, enhanced muscle strength through isometric stabilization exercises, work site modifications, and postural-awareness activities (axial extension-retraction exercises).

Thoracic Inlet Syndrome

Some texts cover thoracic inlet syndrome within the subject matter affecting the shoulder.⁶⁹ Because of the anatomic proximity of the structures involved, this condition is discussed within the context of the cervical spine. Authorities point out that the term thoracic inlet syndrome is a more precise and anatomically accurate term used to describe compression of vascular or neurologic tissues as they exit the “superior triangle opening of the thorax” (Fig. 20-17).^59,69 (This syndrome has been commonly called outlet syndrome in the past.)Specifically, proximal compression of the subclavian artery and vein, as well as the brachial plexus, are the most probable neurovascular factors involved with thoracic inlet syndrome.⁵⁹ Many structures can cause compression of these tissues. Foremost is the presence of a cervical rib, a shortened or hypertrophied anterior scalene muscle, or malunion of the clavicle and subluxed first thoracic rib.^32,59,69 Symptoms of this condition include radicular signs of pain, numbness, tingling, weakness, and skin and temperature changes consistent with neurovascular tissue compression.^32,59,69

Typically, physical therapy management addresses specifically defined limitations of movement and affected bony or soft tissues during the initial evaluation performed by the PT. An individualized comprehensive program of stretching, strengthening, and education can commence once the PT has determined which specific tissues are affected and identified any underlying causes of postural variations.

Soft-tissue stretching focuses on the anterior scalene muscles. The patient is instructed to laterally flex and extend the head to the opposite side of the shortened muscle (Fig. 20-18). Thoracic kyphosis tends to accentuate the symptoms of thoracic inlet syndrome, so pectoral stretching (facing an open doorway with hands on either side and leaning forward) and thoracic extension mobility and strengthening exercises are used to specifically address muscle weakness and soft-tissue restrictions. A host of clinically applicable thoracic extension mobility exercises can be used. Examples include seated scapular retraction, prone scapular and thoracic extension, and seated rowing activities with elastic tubing.

In addition to stretching and strengthening exercises, cervical posture correction is needed; poor cervical posture is a common problem in the workplace.³² To address the forward head posture and tight anterior neck muscles, the patient can perform axial extension or cervical retraction stretching exercises, as described.

The effective management of thoracic inlet syndrome focuses on specific stretching of affected muscles, thoracic mobility, and extension strengthening, as well as education concerning proper cervical spine alignment and the performance of cervical retraction exercises.

Treatment Based Classification: Cervical Spine

Effective management of the cervical spine requires a multimodal treatment approach. The cervical spine TBC system assimilates information from the patient history and physical examination to classify the patient for the most appropriate treatment subgroup.13,23 The five subgroups are labeled mobility, centralization, exercise and conditioning, pain control, and headache. As explained earlier, the patient moves fluidly in and out of these subgroupings during the duration of care. Preliminary research has identified that patients experienced improved outcomes when matched to interventions of their treatment subgroup.²³

The cervical region is the most mobile region of the spine. Impairments in ROM in one vertebral level will change the motion in adjacent levels. The restoration of mobility in the cervical spine may be the first subgrouping chosen by the PT after the initial evaluation. Interventions may include mobilization, active ROM, passive ROM, and manipulation of the thoracic spine.²³ The PT will then initiate exercise in the form of ROM, strength, and conditioning with the PTA. Research suggests patients treated with manual therapy and exercise experience a clinically important reduction in pain.^31,35

An important practical matter to consider when instructing patients to perform cervical ROM exercises is how to stabilize the trunk and shoulders. With both muscle and ligament damage, the long-term effect of healing is fibrous tissue contraction, which results in stiffness, restriction, and limitation of motion.⁶⁷ Therefore to effectively direct the stretch to the affected area, the surrounding structures must be supported and stabilized. For example, if a patient with a lateral flexion injury that results in muscle and ligament damage is instructed to gently stretch laterally away from the side of the injury, the opposite shoulder would elevate (because of the shortened tissues) if the shoulders are not stabilized, rendering the stretch ineffective. To stabilize the shoulder, the patient should perform the stretch while seated and use both hands to grasp under the seat. No shoulder elevation occurs when the patient attempts to stretch the head and neck laterally with the arms fully extended and secured under the seat.

Strengthening and conditioning exercise for the neck and upper quarter include the deep neck flexors. Prevailing theory suggests that stability of the cervical spine is dependent on deep neck flexor strength.³⁹ Jull and co-workers⁴⁰ reported retraining the deep cervical flexors in conjunction with manual therapy to the cervicothoracic spine can effectively decrease neck pain and headache with results being maintained at 1-year follow-up.¹⁵ Precise instruction by the PTA for retraining deep neck flexor is very important for improved patient function.

Treatment of the deep neck flexors begins with the patient in the supine position. This exercise is designed to recruit the deep neck flexor muscles while avoiding co-contraction of superficial neck flexors. Instruction is given to the patient to keep his or her mouth closed, then to gently nod the head, performing a chin tuck. Hold this contraction for 10 seconds while observing for superficial muscle substitution (sternocleidomastoid). Progression of this contraction may occur once the patient is able to sufficiently contract without substitution. To increase intensity, instruct the patient to perform contraction then slightly raise his or her head off the supporting surface. Attention is once again focused on substitution of superficial muscles. Neutral spine position should be reinforced with cueing. The goal is to progress to an inclined position and then more functional positions with increasing control and strength.

Initial strengthening of the cervical spine may also include isometric stabilization exercises. Submaximal contractions and precise techniques are important and must be carefully explained and demonstrated to the patient. For isometric stabilization exercises, the patient performs a series of four-way isometrics in an anatomically neutral cervical spine position. The four-position isometric exercises are forward flexion, lateral flexion (right and left), and extension. In preparing to perform these exercises, the patient must demonstrate the ability to hold his or her head and neck in midline without excessive rotation, lateral flexion, forward flexion, or extension malalignment.

To begin, the patient should sit before a mirror to get visual feedback while maintaining proper head and neck alignment. The proper execution of the first isometric position of forward flexion should be explained and demonstrated. With one hand placed on the midline of the forehead (the patient must bring the hand into the described position and not rotate the head toward the hand), the patient should direct a posterior force to the forehead with the hand while resisting head and neck flexion, thereby stimulating isometric strengthening of the anterior cervical muscles. The patient should gradually and slowly build the resistance using the rule of 10s (gradually initiate isometrics with 2-second submaximal contraction, then hold for 6 seconds, then slowly reduce for 2 seconds) rather than suddenly applying maximal force (Fig. 20-19, A).

The patient should use both hands to support the occiput for the second position. The patient should maintain the head and neck in the anatomic midline position and not allow the head to flex forward. The patient should be encouraged to gradually apply an anteriorly directed force with both hands while resisting extension of the head. This position effectively strengthens the head and neck extensor group (Fig. 20-19, B).

The next position is lateral flexion. While the PTA observes proper head and neck alignment in the mirror, the patient should bring one hand to the side of the head but not allow the head to rotate or laterally flex to meet the hand. The patient should then apply lateral pressure while resisting this force. This position is repeated on the opposite side. No head or neck motion must occur in each position. Usually the patient carries out a series of two to three sets of 10-second isometric exercises two to three times daily. As strength improves, the patient gradually increases the intensity, but avoids sudden or ballistic contractions (Fig. 20-19, C).

Educating the patient about cervical spine postural mechanics is as important as the actual management of any physical dysfunction. One of the most commonly recognized postural malalignment syndromes affecting the cervical spine is a forward head posture. Typically, this posture is characterized by a loss of flexion in the upper cervical spine region and a loss of extension in the lower cervical spine. The patient should perform axial extension or cervical retraction exercises. The PT determines which exercises are appropriate for each patient and identifies which patients are candidates for specific axial-extension exercises.

The PT may determine that the patient responds to repeated movements in a specific directional preference. A centralization phenomenon may occur where distal symptoms in the upper quarter decrease or abolish and symptoms increase or present near the central location of the cervical spine. The patient often responds to repeated retraction exercises in supine and sitting positions. Retraction exercises require the patient to be able to demonstrate a midline neutral position. The patient should sit in front of a mirror initially to perform this exercise correctly. Have the patient imagine that his or her head is resting on a conveyor belt. The patient must be able to align the ears with the shoulders and move the head straight back on the conveyor belt (Fig. 20-20). If done correctly, a “double chin” is produced as the patient moves the head back. If done incorrectly, the head and neck move into extension. The patient should be encouraged to perform this exercise at home for multiple sets throughout the day or as prescribed by the PT.

The centralization subgroup includes repeated movements and also a co-treatment technique with the PT. The PT may request assistance of the PTA to perform a passive upper extremity movement on the patient while the PT mobilizes the cervical spine. The upper extremity movement follows the upper limb neurodynamic tension test for the median nerve. The PT will instruct the direction of the passive movement as well as the static position in order to mobilize the nervous system.

Upper Limb Neurodynamic Tension Test A: Median Nerve Bias

The upper limb tension test is assessed by placing the patient in the following positions:

Impairments in ROM and strength are frequently accompanied by pain. Pain control subgrouping will include those patients with high pain and disability scores noted on outcome measures. They may have been involved in a traumatic event or report very recent onset of symptoms. In many cases, these patients will present with poor tolerance to interventions and possibly elevated fear avoidance beliefs noted on the on the FABQ.²⁸

Managing these patients requires patient reassurance. Gentle active ROM should be encouraged within the patient’s pain tolerance. ROM for adjacent regions such as the shoulder and thoracic spine should also be included. The PT will address appropriate activity modification, which is then reinforced by the PTA. Often these patients will require more frequent collaboration with the PT for progression of interventions.

Mobilization of the Lumbar, Thoracic, and Cervical Spine

Although peripheral joint mobilization is covered in this text, axial skeleton mobilization techniques for the lumbar, thoracic, and cervical spine are not addressed. The extraordinarily complex arrangement and intimate anatomic relationship between vertebral segments and surrounding neurovascular structures require intense, exhaustive study and precise application of techniques after detailed training and clinical practice to be safe, effective, and efficient. The scope of the PTA’s training is not consistent with the demanding working knowledge of neurovascular anatomy, biomechanics, and pathophysiology of the lumbar, thoracic, and cervical spine needed to provide mobilization techniques to these areas.