Lumbosacral Spine Sprain/Strain Injuries

Low back pain (LBP) is a well-known health concern in the United States. Although the incidence of low back injuries is much lower in athletes than in a corresponding population of industrial workers, such injuries are still seen in many athletes. The most common causes of LBP in athletes are musculoligamentous sprains and strains, which occur mainly at the lumbosacral region. This is true of both high-performance, world-class athletes and of "weekend athletes." With over 30 million Americans now involved in organized sports, these back injuries present health concerns on the national level.

(See also the Medscape Reference articles Mechanical Low Back Pain [in the Physical Medicine and Rehabilitation section], Lumbar Disk Problems in the Athlete [in the Sports Medicine section], and Low Back Pain and Sciatica [in the Neurology section], as well as Pain Measurement in Patients With Low Back Pain, Guidelines Issued for Management of Low Back Pain, and Epidemiology of Adolescent Spinal Pain: A Systematic Overview of the Research Literature on Medscape.)

For excellent patient education resources, see eMedicineHealth's patient education articles Low Back Pain and Sprains and Strains.

Most athletes who sustain a low back injury do so while lifting weights during their training sessions or while performing unexpected coupled motions (eg, lateral bending and flexion, lateral bending and axial rotation). During such activities, tremendous loads are placed on the lumbar spine, which may cause a temporary instability and lead to a subsequent injury to the soft tissue that surrounds the spine.

Risk factors for LBP include the following[1, 2] :

• Muscular imbalances or weaknesses of the abdominal and posterior spinal muscles may constitute a risk factor to sustain a low back injury.

• Deficits in the afferent or efferent pathways or proprioceptors are known risk factors for spinal soft-tissue injuries.

• Preexisting structural deformities, such as scoliosis, spondylolysis, or spinal fusions, may predispose to a spinal injury. Preexisting injuries make athletes more vulnerable to sustaining a reinjury of the same area.

  • See the Medscape Reference articles Idiopathic Scoliosis Imaging and Spondylolysis Imaging [in the Radiology section], Lumbosacral Spondylolysis [in the Sports Medicine section], and Lumbar Spondylolysis and Spondylolisthesis [in the Physical Medicine and Rehabilitation section].

  • See also Effectiveness and Cost-Effectiveness of Three Types of Physiotherapy Used to Reduce Chronic Low Back Pain Disability: A Pragmatic Randomized Trial With Economic Evaluation, Biomechanics of the Posterior Lumbar Articulating Elements, Prevalence of Musculoskeletal Disorders at the NFL Combine - Trends from 1987 to 2000, and Lumbar Spine Injuries in Athletes on Medscape.

United States statistics

Studies document that 7-13% of all sports injuries in intercollegiate athletes are low back injuries. The most common back injuries are muscle strains (60%), followed by disc injuries (7%). Athletes are more likely to sustain injuries in practice (80%) than during competition (6%).[3] American football (17%) and gymnastics (11%) are reported to have the highest rates of low back injury.[3]  Among professional dancers, the lumbar spine is a commonly injured area (20% of all injuries).[4]

International statistics

Exact numbers regarding the international frequency of low back injuries are not known; however, a French study reported over 50% of French individuals aged 30-64 years had experienced at least 1 day of LBP over the previous 12 months, and 17% had suffered LBP for more than 30 days in the same 12-month period.[5] The authors noted that the prevalence of LBP varied between men and women, that there was an increased incidence with increasing age for LBP that lasted more than 30 days, and that these data were similar to those of other countries.

In an African study, the mean LBP point prevalence among adults was 32%, with an average 1-year prevalence of 50% and an average life-time prevalence of 62%.[6]

Sprains are ligamentous injuries that are caused by a sudden violent contraction, sudden torsion, severe direct blows, or a forceful straightening from a crouched position. All major ligaments (ie, anterior longitudinal, posterior longitudinal, yellow, intertransversal, capsular, interspinosus, supraspinosus) can sustain sprains; however, the posterior ligaments are more prone to injury. The posterior longitudinal ligament, for example, is the biggest of this group of ligaments and is less developed than its anterior counterpart.

Strains are defined as tears, either partial or complete, of the muscle-tendon unit. Muscle strains and tears most frequently result from a violent muscular contraction during an excessively forceful muscular stretch. Any posterior spinal muscle and its associated tendon can be involved, although the most susceptible muscles are those that span several joints.

Combined with injured tendons and ligaments, all embedded structures may be temporarily or permanently damaged. Of major interest are proprioceptors that play a crucial role in the motor control of the spine. An inhibited motor control weakens spinal stability and may lead to chronic back problems or reinjury.

The lumbar spine bears tremendous loads: the large, superimposed body weight interacts with additional forces that are generated by lifting as well as other activities that involve powerful forces.[7, 8, 9, 10, 11] The lumbar spine and the hips are responsible for the mobility of the trunk. The L4-5 and L5-S1 areas bear the highest loads and tend to undergo the most motion. Consequently, these areas are found to sustain the most spinal strain or sprain injuries. In addition, load-bearing strain and sprain injuries most frequently occur during the strongest coupling patterns (ie, lateral bending with flexion-extension, axial rotation with lateral bending).

The bony architecture and the ligamentous elements constitute the structural components of the spine.[12] The muscles and tendons constitute the dynamic elements. With all elements intact, the biomechanical function of the spine is normal. The intrinsic translatory and rotatory stability of the spine is provided by the ligaments. The contribution of a given ligament depends not only upon its particular strength, but also upon its location. Moreover, a ligament may contribute relatively more to either the translatory or rotatory stability, depending upon the loading circumstances. Assuming that all ligaments are made of the same material, the strength of a ligament is proportional to its cross-sectional area. A ligament with a larger cross-sectional area provides greater stability and less displacement when the functional spinal unit (FSU) is subject to physiologic loads.

Another factor that contributes to spinal stability is the distance of a ligament from the center of rotation.[13] A ligament that is located close to the center of rotation provides much less stability against bending than a ligament that is further away from the rotation center. The interspinous ligaments in the adult lumbar spine are frequently absent, ruptured, or degenerated and do not contribute to stability of the spine. However, supraspinous ligaments do play a role in stabilizing the spine. Muscles provide stability to the spine during all dynamic movements and actions. Injured trunk muscles can decrease spinal stability if the intact muscles are not able to compensate for the dysfunction of the injured unit.

Spinal instability can occur as a result of trauma, disease, surgery, or some combination of the 3 causes. Clinical instability is defined as a loss of the ability of the spine to maintain relationships between vertebrae under physiologic loads in such a way that (1) there is neither initial nor subsequent damage to the spinal cord or nerve roots, and (2) there is no development of incapacitating deformity or severe pain. Instability leads to abnormal kinetics (stiffness) and/or kinematics (coupling patterns).

When the tissues surrounding the spine are damaged, structures embedded within those tissues may also become temporarily or permanently harmed. Proprioceptors, including muscle spindles, Golgi tendon organs, and joint receptors, are of great importance for postural control. Damaged proprioceptors weaken the stability of the spine and may lead to reinjuries or chronic problems. Although some studies document changes in the normal quality and quantity of motion, there has been no compelling correlation of either with pain behavior.

Obtain the following key information:

• The mechanism of injury, with an exact description of the event leading to the pain

• The exact localization and duration of the pain

• Any pain radiation

• Movements that aggravate or minimize the pain

Typical symptoms are pain and spasm that are localized over the posterior lumbar spinal muscle bellies lateral to the spinous process or at the insertion of the muscle at the iliac crest.

If the injury is confined to a sprain or strain injury, then structural deformities, a generalized midback pain indicating disc involvement, and neurologic symptoms should be absent.

(See also the Medscape Reference articles Lumbar Disk Problems in the Athlete [in the Sports Medicine section], Lumbar (Intervertebral) Disk Disorders [in the Emergency Medicine section], Lumbar Degenerative Disk Disease [in the Physical Medicine and Rehabilitation section], and Lumbar Disc Disease [in the Neurosurgery section].)

Range of motion (ROM), particularly in flexion, is usually painful and decreased.

Any neurologic compromise, (eg, numbness in the lower extremity, motor weakness) or any urinary or fecal incontinence syndrome indicates the possible presence of disc prolapse, nerve root impingement, or spinal canal stenosis.[14]

(See also the Medscape Reference articles Urinary Incontinence [in the Emergency Medicine section], Fecal Incontinence [in the Obstetrics/Gynecology section], Nerve Entrapment Syndromes of the Lower Extremity [in the Orthopedic Surgery section], Spinal Stenosis [in the Neurosurgery section], and Spinal Stenosis and Neurogenic Claudication [in the Physical Medicine and Rehabilitation section].)

With the patient in a standing position, evaluate for obvious deformities, changes in alignment, or difficulties in achieving changes in position or full ROM. Evaluation of these signs may provide clues to muscle spasm(s) and activities that worsen the patient's pain.

Palpation of painful area: Palpation, performed with the patient in a prone position, helps to reveal the area and the size of muscle spasm(s) and the location of any point tenderness, if present. A point-specific midline back pain between the spinous processes indicates a ligamentous injury or lumbar interspinous bursitis ("kissing spines").

Neurologic examination: Evaluation of the lower extremities should include a motor examination, a sensory evaluation, and reflex testing at the knees and ankles. The straight-leg raising test helps to evaluate disc involvement, sciatica, or a neurologic deficit. A positive Patrick test points to a sacroiliac joint inflammation, but this test should be negative in lumbosacral sprains and strains. (See also the Medscape Reference article Sacroiliac Joint Injury.)

Laboratory studies are generally not indicated as a routine diagnostic tool in the evaluation of lumbosacral spine sprain/strain injuries.

Suggestive findings for rheumatic disease, such as ankylosing spondylitis, are increased levels of human leukocyte antigen (HLA)-B27, leukocytes (4.5-11 x 103), and erythrocyte sedimentation rate (ESR) (male: 0-20 mm/h; female: 0-30 mm/h).

Although sprain and strain injuries only involve the soft tissue, standard anteroposterior and lateral radiographs of the lumbar spine should be routinely obtained to (1) exclude a fracture, rheumatic disease, or a tumor growth; and (2) to evaluate degenerative joint disease as well as overall spinal alignment.

If an individual with LBP does not respond to conservative treatment and develops neurologic signs, a computed tomography (CT) scan or magnetic resonance image (MRI) may be considered to evaluate for disc herniation and involvement of the nerve roots. (See also the Medscape Reference articles Disk Herniation Imaging [in the Radiology section] and Herniated Nucleus Pulposus [in the Orthopedic Surgery section].)

Rehabilitation program

Physical therapy

Cold therapy for a short period (up to 48 h) should be applied to the affected area to limit the localized tissue inflammation and edema. The physical therapist may recommend electrical stimulation to be completed in conjunction with the ice to help further decrease pain and inflammation. The patient should also be instructed in the proper body mechanics with everyday tasks (eg, getting in/out of bed) to ensure no further unnecessary stress is applied to the injured area.

Medical issues/complications

In the acute phase of LBP, bed rest may be considered for a short period (< 48 h). However, most studies now support the affected individual maintaining some activity level, even in the acute phase, as this results in a more rapid functional recovery. Sports activities, particularly those involving weight lifting and extreme ROM of the spine, should be avoided as long as the patient's pain persists.

Other treatment

Intramuscular (IM) injections of muscle relaxants or nonsteroidal anti-inflammatory drugs (NSAIDs) at the site of the pain may help to control muscle spasms.

• Avoid manipulation of the affected area during the acute phase of the injury.

• A lightweight lumbosacral corset may also be used to help control muscle spasms.[15] Use of the corset should be discontinued as soon as the spasms have resolved.

Rehabilitation program

Physical therapy

Physical therapy in the recovery phase of LBP initially involves a light program of muscle stretching and strengthening for the abdominal and paraspinal muscles. In conjunction with this program, various modalities (eg, heat, ice, ultrasound, electrical stimulation) and soft-tissue massage may help make the athlete more comfortable.

Recreational therapy

In everyday life, the athlete should be instructed to maintain an upright posture of the spine when sitting, standing, and lifting or moving things.

Surgical intervention

Surgery is generally not necessary in the treatment of lumbosacral spine sprains or strains.

Consultations

If the athlete does not have a good response to conservative treatment, and radiographs or laboratory tests suggest a rheumatic disease, the athlete should be seen by a rheumatologist. If a neurologic deficit surfaces or if one that was previously noted progresses, a spine surgeon should be consulted.

Other treatment (injection, manipulation, etc.)

Light muscle massage to relax the involved muscle group and chiropractic manipulations have been reported to relieve muscle pain and spasms, thus making the athlete more tolerant to his or her rehabilitation exercise program. However, IM injections of muscle relaxants may still be necessary.

Rehabilitation program

Physical therapy

A physical therapy program must be tailored to the individual patient and should take into consideration the initial status of the patient's pain, muscle strength, and shortening of any given muscle group. The program should then be adjusted in every session according to the progress that is made in the patient's pain reduction, strength, and flexibility. Physical therapy programs may need to be implemented for 1-2 weeks, or they may need to be continued for several months.

A balance between muscle strengthening and flexibility must be sought. When the affected muscles are strong enough, strengthening and flexibility exercises should also be performed on labile surfaces (eg, Swiss ball [Sissel-Online Ltd, Mission, British Columbia, Canada]) to rehabilitate the proprioceptors. All exercises should take into consideration the abdominal, paraspinal, and hip muscles.

The goal of pharmacotherapy is to reduce patient morbidity and prevent complications. In acute injuries, pharmacotherapy should usually not exceed 6 weeks of treatment.

Class Summary

In the acute phase, muscle relaxants (IM injection or tablets) help to treat muscle spasms and facilitate light physical therapy.[16] However, muscle relaxants have not been shown to shorten or alter the course of the injury process.

Methocarbamol (Robaxin)

Exact mechanism in humans not known. May be due to general central nervous system (CNS) depression. Has no direct action on contractile mechanism of striated muscles, the motor endplate, or the nerve fiber. Indicated as an adjunct to rest, physical therapy, and other measures for the relief of the discomfort associated with acute pain and painful musculoskeletal conditions.

Class Summary

NSAIDs are generally used to treat muscle pain in the acute and maintenance phases of treatment. These drugs usually have anti-inflammatory, analgesic, and antipyretic activities. The ability of NSAIDs to inhibit prostaglandin synthesis may be involved in the anti-inflammatory effect; these agents are indicated in the acute and maintenance phase of the pain treatment for lumbosacral injuries.

Selective cyclooxygenase-2 (COX-2) inhibitors are generally not recommended as first-line treatment.

Diclofenac (Voltaren)

Has anti-inflammatory, analgesic, and antipyretic activities. Used to treat acute and continuous pain. In general, patients should be maintained on the lowest dosage of diclofenac that is consistent with achieving a satisfactory therapeutic response.

Ibuprofen (Ibuprin, Advil, Motrin)

Drug has anti-inflammatory, antipyretic, and analgesic activities. Mode of action not known. However, ability to inhibit prostaglandin synthesis may be involved in anti-inflammatory effect. Smallest dose that yields acceptable control of pain should be employed. A therapy longer than 3-6 months may result in gastrointestinal bleeding or ulcers; long-term therapy must be closely observed.

Symptoms usually decrease after 3 days, and they should subside between 1 and 6 weeks. A safe return to play is only possible when the patient feels neither pain nor discomfort, so that the spinal muscles can react and perform appropriately. Pain-avoiding behavior that is caused by any remaining symptoms could place the patient at risk for reinjury. A return to play under pain medication is not recommended because the medication may take away the body's natural warning signal to stop a painful and subsequently harmful action, thereby increasing the risk for aggravating the existing injury or causing reinjury.

Use of a lumbosacral muscle corset that supports all the trunk muscles, balancing the abdominal and back muscles, helps to stabilize the lumbar spine.[15]

The stabilization of the spine also depends on appropriate and fast muscle reactions to suddenly changing postures of the spine. Studies suggest that the proprioceptive abilities of the trunk muscles play a key role in the prevention and rehabilitation of low back injuries. Exercises that include or emphasize proprioceptive activities (eg, Swiss ball) help the patient to expedite recovery from the injury and may prevent further injuries. A good upright posture while the patient is standing, sitting, and lifting during everyday life and the implementation of exercise routines helps to take unnecessary strain off the spinal structures.

Most (90%) lumbosacral injuries have been reported to subside within 6 weeks irrespective of treatment. The remaining 10% of such injuries may develop into chronic lumbosacral pain without treatment.

All athletes should be educated about proper warm-up exercises, proper stretching exercises, and correct weight-lifting techniques. Furthermore, firm, upright posture while the patient is standing, sitting, and lifting provides additional bracing for the spine, thus minimizing the stress on the spinal tissues.