Current Clinical Concepts: Management of Common Lumbar Spine Posterior Column Disorders in Young, Active Individuals

History

Posterior column disorders characteristically present with an insidious onset of pain and a duration of ≥3 weeks^12,24 in individuals older than 10 years of age and may have coincided with rapid growth or puberty.^12,13 Although the condition can develop in any population subjected to repeated compressive stresses on the pars interarticularis, 3 classic types of patient presentations have been described: (1) a female gymnast or dancer with hypermobility, increased flexibility, and an increased lumbar lordotic posture; (2) a strong man in peak growth velocity with limited flexibility and tight spinal erectors; and (3) an athlete who recently began vigorous sport participation with no conditioning.¹² Typical presentations of posterior column disorders include complaints of pain after repeated extension or rotation of the lumbar spine, often described as a dull ache or a severe sharp pain, that is alleviated with rest.^{5,12,13,21,22} Pain that does not resolve with rest may indicate possible spondylolisthesis, as these patients more often report difficulty falling asleep, waking up due to pain, and pain that is worse while sitting or walking.²⁵ When questioning an individual, symptoms that deserve particular attention include a history of low back pain triggered by hyperextension or rotation with regular intake of over-the-counter anti-inflammatory medication.¹²SOR: C

Observation and Palpation

Patients with posterior column disorders usually display normal gait unless they are compromised by pain, which is characterized by a forward lean, shortened stride length, and flexion of the hips and knees secondary to hamstrings contracture.^12,13,24 This classic bent-knee, hip-flexed posture, called the Phalen-Dickson sign (Figure 1),^13,26 is common in patients with spondylolisthesis during sit-to-stand and ambulation. In individuals with advanced spondylolisthesis, a visible step-off may be seen along the lumbar spinous processes.^13,22,24 Palpation of the step-off deformity demonstrated diagnostic utility in the general population but has not yet been investigated in a young or athletic population.²⁷SOR: C

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Selective Tissue Tension Testing

Patients with posterior column disorders often experience limitations in their lumbar spine and hip range of motion due to pain or muscle tightness. Active or passive extension of the spine frequently elicits pain. Pain may also occur during resistive range of motion from flexion into extension,^12,13,21,24 and individuals often demonstrate tightness of the hamstrings and occasionally the hip flexors.^5,12,21,28 They may display hypermobility of the affected lumbar spinal segments, with hypomobility of adjacent segments and corresponding weakness of the abdominal and gluteal muscles.^5,12,28SOR: C

Neurologic Examination

Generally, neurologic testing is normal in patients with posterior column disorders.¹² However, individuals who present with advanced cases or lower extremity radicular pain, altered sensation, weakness, or bowel or bladder disturbance need diagnostic imaging via a physician.^9,24 In 1 study,²⁹ radicular symptoms appeared to be more prevalent (P < .01) in participants with pars fractures who exhibited vertebral instabilities (52 of 84 patients with radicular symptoms, 61.9%) than those with pars fractures who did not have an instability present (16 of 76 patients, 21.1%). SOR: C

Special Tests

With varying levels of success, an assortment of special tests has been used to provoke a pain response by loading the possible pars fracture, detect motor control between the trunk and lower extremity, or assess instability in the vertebral column in young active individuals. One of the most common orthopaedic special tests is the stork test, or single-legged hyperextension test (Figure 2). Despite its frequent use, the stork test had low utility in detecting an active spondylolysis in a population of young active individuals with low back pain: sensitivity = 0.50, specificity = 0.46, positive likelihood ratio = 1.01, and negative likelihood ratio = 0.74.^5,22,25,30 In the face of this evidence, clinicians should question the utility of the stork test and consider other assessments. The active straight-leg raise test has been used to assess lumbopelvic motor control (Figure 3). It is widely thought to be a valid and reliable tool, with sensitivity of 0.87, specificity of 0.94, a positive likelihood ratio of 16.17, and a negative likelihood ratio of 0.03 in women with lumbopelvic pain of various causes and degrees of severity.^13,31,32 Clinicians might choose the active straight-leg raise test to assess the patient's ability to transfer load between the spine and lower extremities. The passive lumbar-extension test (Figure 4) assesses segmental lumbar instability and had reported sensitivity of 0.84, specificity of 0.90, a positive likelihood ratio of 8.84, and a negative likelihood ratio of 0.17.^25,32,33 Some believe the passive lumbar-extension test is the most accurate method for detecting structural instabilities in the spine to predict an unstable spondylolisthesis.³¹ The prone instability test (Figure 5) also evaluates segmental lumbar instability and is more often positive in patients with chronic pain. Its sensitivity of 0.44, specificity of 0.45, positive likelihood ratio of 0.80, and negative likelihood ratio of 1.24 give it limited diagnostic use as an independent test.³¹ However, as a component of the lumbar-stabilization clinical prediction rule, the prone instability test may help to predict the response to therapeutic exercises.^31,34SOR: C

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Diagnostic Imaging

If a posterior column disorder is suspected on physical examination, imaging may be used to confirm its presence or absence.²⁸ Yet diagnostic imaging is often overused for nonspecific low back pain and is not always necessary for successful management. In fact, when the patient presents with the signs and symptoms of a posterior column disorder, it is appropriate to begin treatment in the absence of diagnostic imaging. The most common diagnostic imaging techniques used to detect posterior column disorders are radiographs, computed tomography (CT), magnetic resonance imaging (MRI), single-photon emission computerized tomography (SPECT), and bone scintigraphy.²² No widely accepted criterion standard exists for radiographic diagnosis,^12,23,28 though the North American Spine Society “Clinical Guidelines for Multidisciplinary Spine Care Report”²² designated lateral radiographs and MRI as the most effective imaging tools for diagnosing spondylolisthesis, and CT was regarded as effective when MRI was contraindicated. When radiographs were the only diagnostic tool available, several research groups^5,21,23 observed that lateral radiographs combined with anteroposterior and 45° left and right oblique (where the visual aid “Scottie dog” could be seen) views revealed 96.5% of pars defects. SOR: C

Medication

Whether nonselective nonsteroidal anti-inflammatory drugs and selective cyclo-oxygenase (COX)-2 inhibitors should be used as anti-inflammatory or analgesic medications in patients after a fracture or stress fracture is inconclusive. These drugs may interfere with prostaglandin production, thereby impairing the inflammatory reaction after a bony fracture. An animal study³⁵ suggested that the effects of COX-2 inhibitors depended on the timing, duration, and dosage. Physicians may consider a short course of anti-inflammatory medications for pain management in individuals with posterior column disorders but may also want to avoid these in those at risk for delayed fracture healing. Oral corticosteroid medication may be tried depending on patient symptoms and physician preferences. Medications such as prednisone and methylprednisone are frequently administered, but outcomes have not been widely published, and long-term administration of glucocorticoids inhibited the bony healing process in mice.³⁶ Spinal injections of various types (eg, interlaminar and transforaminal epidural) have increased in popularity as nonoperative treatment options for athletes with symptomatic low back pain, such as lumbar disc herniation.³⁷ Spinal injections for the posterior column disorder of a young athlete should only be performed by an experienced physician when there is a proven chronic, nonunion injury in the pars interarticularis to avoid problems with bony healing and only after a detailed discussion of risks and benefits has occurred. As with all therapeutic interventions, ATs should be aware of the potential risks and benefits associated with each medication offered. SOR: C

Rest and Bracing

One of the most common forms of conservative care prescribed by physicians is rest with use of a brace to help achieve bony union of the pars fracture.^4,38 Some have suggested patients should rest from sports activities for at least 3 months,^12,39 but for highly competitive and active individuals participating in sport, this may not be feasible, and the amount of rest can vary from 2 weeks to 6 months depending on symptom severity.⁵ Although rest is typically recommended for all individuals with a posterior column disorder, it may have the highest utility in those with symptomatic spondylolysis and grade I spondylolisthesis. Investigators⁴⁰ found that after 6 weeks of activity modification, Oswestry Disability Questionnaire scores indicated that 18 of 23 (78%) patients had no pain or limitation of function, 22 of 23 (96%) had minimal disability, and only 1 of 23 (4%) had moderate disability. Bracing of the lumbar spine was also a frequent intervention for adolescent athletes,^31,39 despite being criticized by clinicians and patients as expensive and uncomfortable. It is thought a brace would help reinforce proper movement patterns, limit aberrant spinal movements, and serve as an external signal to remind the patient and others of the injury. Despite the possible benefits, wearing a brace could be counterproductive to the concurrent rehabilitation and exercise programs usually prescribed.⁴⁰ Regardless of these concerns, several investigators demonstrated the effectiveness of a lumbar spine brace. Among participants who wore a lumbar spine brace that limited lordosis until pain disappeared, 87% were able to return to sport between 1 and 16 months.⁴¹ Another group found that 80% of their patients with a diagnosis of spondylolysis had good to excellent results with full return to sports after 6 weeks of wearing a brace.⁴² It is important to note that neither study included a control group for comparison, so the improvements could have reflected the effect of rest alone, wearing the brace, or the combined effect of rest while wearing the brace. Clinicians should use good clinical judgement and practice principles of patient-centered care when making decisions about the use of rest and a brace to treat disorders of the posterior column. SOR: A

Therapeutic Exercise

Many acute posterior column conditions do not heal radiographically, yet in 1 meta-analysis⁴³ of 15 observational studies in children and young adults with spondylolysis, nearly 84% of individuals had a successful clinical outcome after rehabilitation. A retrospective investigation⁴⁴ of patients aged 5 to 21 diagnosed with spondylolysis with an average follow-up of 8 years showed that 90% of individuals self-reported a return to sport, 78% described low levels of pain (≤3 out of 10), and 58% indicated no pain. These results suggested that patients can successfully rehabilitate this condition through focused therapeutic exercise and generic aerobic exercise. The authors²⁸ of a literature review found that several studies of different spine conditions, including posterior column disorders, supported the use of core-strengthening exercises, specifically exercises activating and isolating the transverse abdominis, internal oblique, and multifidi to structurally stabilize the lumbar segments. These deep abdominal muscles and the lumbar multifidus are particularly relevant to those with posterior column instabilities due to their effects on intra-abdominal pressure and lumbar stability via cocontraction. Other researchers^40,45,46 noted that lumbar-stabilization exercises were an effective treatment option for controlling pain and improving function in young athletic patients diagnosed with posterior column disorders. A focused therapeutic exercise program should help improve function and return a significant majority of athletes to sport competition. SOR: A

Proposed Management Protocol

As part of the effort to engage in injury prevention, ATs should try to identify individuals at high risk of developing a posterior column disorder. Those who participate in sports such as gymnastics, wrestling, swimming and diving, dance, crew, or high jump, in which incidence rates are highest, would benefit from patient education on proper biomechanics and movement patterns for their sport. In these populations, screening to address possible muscle length-tension imbalances, strength deficiencies, or poor movement and training habits may help prevent the condition altogether.

For those who become symptomatic, comprehensive management often includes multiple interventions, typically starting with activity modifications or restrictions, bracing, targeted therapeutic exercise, and patient education. For less severe conditions, relative rest and activity modifications may be appropriate. In those with more significant disorders or who display segment displacement (spondylolisthesis), an antilordotic modified Boston brace should be used. The length of time in the brace will depend on many factors, but practitioners should account for the findings of diagnostic imaging, the patient's reported pain, and the patient's clinical presentation and continue bracing at least until metabolic activity is no longer noted on the SPECT bone scan. Whether or not a brace is used, the individual should be educated on body mechanics, proper lifting techniques, and avoiding spinal motions such as rotation and hyperextension that can delay or prevent healing.

A targeted and progressive therapeutic exercise program should be initiated to address motor control and strength of the abdominal musculature and spinal stabilizers. In general, we recommend a 5-part exercise progression before a return to sport or activity is considered (Table 2). This generic progression can be used for any type of posterior column fracture. However, the more involved or severe the condition, the longer the recovery process may be for the patient.

Table 2 Sample Rehabilitation Protocol for a Patient With Posterior Column Disorder

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It is common for patients to continue wearing their brace while initiating therapeutic exercise. They should be allowed to perform their exercises outside of the brace and then resume wearing it during activities of daily living until discontinued by a physician. Step 1 in the progression involves exercises that are isometric and static in nature. These emphasize proper mechanics, spinal positions, and breathing patterns. Once static stability of the spine is achieved, step 2 introduces dynamic movements of the extremities to increase the load on the trunk while the patient maintains a static spine position. This stage is critical for teaching patients how to dissociate movement in the extremities from the trunk. This stage is also typically when cardiovascular aerobic exercise, such as stationary cycling, may be resumed. Once the person is strong enough to control a neutral spine independent of movement across the extremities, progression into step 3 occurs, and dynamic spinal movements are begun. It is important for patients to focus on proper movement patterns and mechanics during this portion of the progression. When they can maintain neutral spine mechanics during movement, step 4 involves neuroreactive and plyometric activities. The intensity of activity and number of foot contacts should be carefully monitored to avoid potential setbacks in the recovery. Step 5 advances to more sport-specific or functional activities to directly mimic the activities the patient will return to on release from care. Intensity should be carefully observed for return of symptoms during each stage of recovery, but particularly in step 5, as repetitive stress and intensity are increased.

The time required to return to play can vary significantly and must be tailored to the patient and the severity and symptoms present. Criteria for a return-to-play decision in competitive athletes were lacking and inconsistent across studies. The majority of the reported criteria were subjective or based on time, diagnostic imaging, or patient symptoms. These included full range of motion, normal strength, appropriate aerobic fitness, adequate flexibility and movement, lack of tenderness to palpation, and completion of a functional activity progression without pain.⁴⁷

Patients who have an extended recovery or who are unable to see progress during their recovery can experience nonphysiological symptoms such as fear avoidance and pain catastrophizing. The biopsychosocial model has been a popular way of contextualizing the interaction of the biological system with the psychological system in different social situations, factors, or constructs. Although conservative care with rest, brace use, and therapeutic exercise was typically an effective treatment strategy, in some research on patients with posterior column disorders, the investigators focused on fear-avoidance and pain-catastrophizing treatments as opposed to traditional strengthening exercises. The results from this approach were equivalent to those of traditional rehabilitation programs.^48–50 These studies were conducted mostly in older populations with chronic degenerative spondylolisthesis, yet they cast an interesting light on the potential application in a younger, competitive athletic population.

Other Conservative Treatments

Several other treatments have been used or suggested by sports medicine professionals to help manage those with posterior column disorders or nonspecific low back pain. A summary of additional conservative treatments with SOR grades is presented in Table 3. Many of these treatments lacked consistent findings in patients with posterior column disorders.

Table 3 Conservative Interventions for Posterior Column Disorders and Strength of Recommendation

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Surgical Intervention

Most individuals with lumbar spine posterior column disorders respond well to conservative measures. However, some continue to have pain and disability: 42% of 1 sample reported low levels of continued pain after conservative treatment, and 67% described enough pain to interfere with activities.⁴⁴ Some experts⁶³ have recommended surgical intervention for those who are athletes, have low back pain that persists for 6 to 12 months, and have documented nonunion of the pars interarticularis or in those whose pain did not resolve after rest and immobilization in a brace. A detailed survey of the different surgical interventions performed by orthopaedic surgeons was beyond the scope of this review. However, common surgical procedures include surgical fixation, decompression via laminectomy, bone grafting of the fracture site, or a lumbar fusion, depending on the degree of instability present. The authors⁵¹ of a systematic review of 13 studies of patients who underwent surgical treatment found that 87.8% had a successful outcome and returned to sport 6 to 12 months after their surgery. Most of the surgeons limited participation in collision sports after surgery.⁵¹ Appropriate surgical care may allow individuals who do not respond to conservative measures to achieve positive outcomes and return to competition.