Spine Evaluation, Clinical Examination, and Imaging
Brandon J. Rebholz, MD
Dr. Rebholz or an immediate family member serves as a paid consultant to or is an employee of Biomet and serves as an unpaid consultant to Ulrich Spine.
ABSTRACT
The breadth of spinal pathology and conditions requires that practitioners be confident in obtaining a complete history and performing a comprehensive physical examination in different clinical settings. This is further supplemented by the use of safe and appropriate imaging to establish the diagnosis and augment intraoperative accuracy. Through the proper understanding and use of these techniques, providers can continue to improve on delivering safe, high-value care to patients with spinal conditions.
Keywords: spine differential diagnosis; spine imaging; spine physical examination
Introduction
Successful care of patients with neurologic and musculoskeletal problems begins with arriving at the proper diagnosis. The importance of developing an accurate and efficient process to arrive at these diagnoses cannot be overstated. It is through a thorough history, complete physical examination, and appropriate imaging modalities that the correct diagnoses can be made, and best practice treatment recommendations can be offered, optimizing safe, value-driven care.
Physical Examination
The comprehensive history and physical examination are the initial interactions set on delivering the correct diagnosis and subsequent treatment recommendations to patients. Symptoms can often be similar for spinal and appendicular musculoskeletal etiologies: cervical spine symptoms can often mimic shoulder problems, brachial plexopathies, and peripheral compressive neuropathies; lumbar spine symptoms are often very similar to those originating from the hip, sacroiliac joint, or even vascular insufficiencies; patients with myelopathy may present with vague symptoms that could be mistaken for other systemic or neurologic disorders. By having a thorough understanding of the entirety of the neurologic and musculoskeletal system, providers can guide patients through the most appropriate treatments, while limiting unnecessary workups or procedures.
The evaluation begins with elucidating an accurate history. The presenting symptoms should be described by the patient and additional history developed with the provider. This history should ultimately include the symptom location with or without associated radiation, severity, onset, duration, quality and character, aggravating or alleviating factors, and previous related treatments. Additional attention should be given to the patient’s other medical diagnoses. Caution should be taken attributing symptoms to these underlying medical diagnoses as symptoms can often be multifactorial. In the acutely injured patient, specific attention should be given to the mechanism of injury and associated injuries. By completing a comprehensive history, the provider can often develop an appropriate differential diagnosis, which can be further narrowed by the examination.
The initial examination of the spine patient should include a complete neurologic and musculoskeletal examination. Attention is given to the specific myotomal and dermatomal distributions to determine potential level of pathology. Strength testing is graded on a scale of 0 to 5. In the upper extremities strength is described as it pertains to shoulder abduction (C5); elbow flexion and wrist extension (C6); elbow extension, wrist flexion, and digit extension (C7); digit flexion (C8); and the digit abduction (T1). Similarly, in the lower extremities strength is tested in hip flexion (L2), knee extension (L3), ankle dorsiflexion (L4), great toe extension (L5), and ankle plantar flexion (S1). The sensory examination is tested and described in dermatomal distributions for sensation to light touch or pressure, pin prick, and temperature. Utilization of the examination in conjunction with a knowledge of the somatotrophic organization of
the spinal cord can help distinguish different incomplete spinal cord injury patterns in the acute or traumatic setting.
the spinal cord can help distinguish different incomplete spinal cord injury patterns in the acute or traumatic setting.
Sacral sparing is a defined as preservation of sensory or motor function of the most caudal aspect of the spinal cord. This includes sensation to light touch, pin prick, or deep anal pressure in the S4 and S5 nerve root distributions and voluntary contraction of the external anal sphincter as assessed by digital rectal examination. Complete spinal cord injury is defined as no sensory and/or motor function at the sacral segments, whereas incomplete spinal cord injury maintains some sacral sensory and/or motor function.1 These components of sacral sparing can have some prognostic significance in that more components of sacral sparing present within the first 30 days, the greater the likelihood of improvement in American Spinal Injury Association (ASIA) Impairment Scale (AIS) at 1-year follow-up.2 This improvement in AIS does not necessarily equate to meaningful functional improvement, so caution should be used when communicating potential prognostic information to patients and families.
Reflex examination is routinely performed in the upper and lower extremities. Deep tendon reflexes are tested about the biceps (C5/C6), triceps (C7), brachioradialis (C6), patellar (L4), and Achilles (L5/S1) tendons. Hyperreflexia is potentially consistent with upper motor neuron dysfunction, whereas hyporeflexia is consistent with lower motor neuron dysfunction. Additional reflex testing is elicited through the testing of the Hoffman sign, Trömner sign, abdominal reflexes, Babinski reflex, and bulbocavernosus reflex. These additional tests are used for specific purposes and may or may not be included depending on the clinical scenario.
Hoffman’s sign is performed by flexion and release of the distal interphalangeal joint of the middle finger while observing the interphalangeal joints of the ipsilateral index finger and thumb. Reflexive flexion of the interphalangeal joint of both the thumb and index fingers indicates a possible central compressive pathology in the cervical spine. A recent systematic review was performed to determine the utility of the Hoffman’s test as a screening tool for cervical spondylotic myelopathy. The presence of the Hoffman sign has a positive predictive value of 68% (LR of 2.6 with 95% CI 1.8 to 3.9) and negative predictive value of 70% (LR of 0.51 with 95% CI 0.3 to 0.6) as compared with the benchmark of MRI with associated spinal cord compression and loss of surrounding CSF with or without cord signal change.3 There is a known incidence of positive Hoffman’s sign in the asymptomatic population of approximately 0.3% to 2%.4 As such, the authors conclude that a positive Hoffman’s sign is useful only in the context of the complete history and physical examination. The presence of hyperreflexia, Hoffman and/or Trömner sign, upgoing toes for Babinski testing, and sustained ankle clonus can be used together to inform the possible diagnoses of myelopathy.5,6
The bulbocavernosus reflex is most commonly used in the acute posttraumatic setting. This reflex is elicited during the digital rectal examination by either gently pulling on an inserted Foley catheter or squeezing the glans penis. Subsequent involuntary contraction of the external anal sphincter is consistent with an intact reflex. In the setting of an acute spinal cord injury, this indicates the termination of spinal shock, at which time determination of spinal cord injury severity can be made according to the ASIA standards. The bulbocavernosus reflex can also distinguish between conus medullaris syndrome or lower thoracic cord compression/injury and cauda equina syndrome. Absence of the bulbocavernosus reflex outside the setting of spinal shock would be consistent with lower motor neuron dysfunction interrupting this reflex arc.
Inspection of the back allows for assessment of the skin and soft tissues. In the setting of acute trauma, significant ecchymosis would be indicative of a possible underlying fracture. If a spinal cord injury or spinal fracture is suspected, this examination should be performed only initially in conjunction with the rectal examination as described previously. Palpation for asymmetry and midline tenderness may be indicative of underlying fractures. In the routine clinical setting, percussion of the spine can distinguish between acute and chronic compression fractures.
Spinal deformity can best be assessed in the standing position. The pelvis and shoulders are examined for symmetry. Adam’s forward bend test allows for evaluation of the rotatory component of scoliosis, and location of any notable prominence should be noted. If the patient has positive sagittal balance, then the forward gaze may be impacted. Additionally, lumbar lordosis may be compromised, and hip flexion contractures may develop as compensatory mechanisms in an attempt to maintain as upright a walking posture as possible.
Observation of gait is an important component of both the neurologic and musculoskeletal examinations. Initiating from a seated position will allow the practitioner to observe if there is a component of “start-up” pain consistent with potential hip pathology. If the patient demonstrates an antalgic gait, then this could be indicative of hip arthritis or a compressive radiculopathy. A Trendelenburg gait could be related to an L5 nerve root compression with subsequent hip abductor
weakness. In this case the patient’s pelvis will drop on the unaffected side as the patient leans her torso toward the affected side.
weakness. In this case the patient’s pelvis will drop on the unaffected side as the patient leans her torso toward the affected side.
Distinguishing between spinal pathology, hip pathology, and sacroiliac joint (SIJ) dysfunction can be difficult as symptoms often have overlapping patterns. Radicular pain often begins in the buttocks, then radiates to the thigh and potentially to the leg and foot, typically in dermatomal patterns. Intra-articular hip pathology typically results in a referred pain pattern to the buttock, groin, thigh, knee, and low back. Sacroiliac joint pain similarly presents with pain in the low back, buttock, and thigh.
The diagnostic utility of individual physical examination tests in confirming lumbar radiculopathy has been shown to be somewhat equivocal.7,8 As such, a combination of the aforementioned neurologic tests along with neural tension tests including the straight leg raise and femoral stretch tests can improve the sensitivity and specificity for radiculopathy. These should be performed in the supine and prone positions, respectively.
Testing of the hip joint is typically done in the supine position, with the examiner passively flexing the hip joint past 90° and providing an internal rotation force through the hip joint. Gentle circumduction can also be performed. Pain provocation in the groin, buttock, thigh, and potentially the knee would be consistent with intraarticular hip pathology. Hip range of motion is concomitantly assessed. This is also the best position to assess for hip flexion contractures as these can easily be overlooked in the seated position.
Sacroiliac joint dysfunction can present a significant diagnostic challenge. Specific testing of the SIJ is typically performed with six provocative maneuvers: hip flexion, abduction, and external rotation (FABER or Patrick test) (Figure 1, A), pelvic compression, pelvic distraction, thigh thrust, sacral thrust, and Gaenslen test (Figure 1, B). As with other physical examination tests, the utility of individual tests is limited; however, the sensitivity and specificity of these tests are improved when three or more provocative maneuvers reproduce symptoms.9 Confirmation of the SIJ as the source of pain can be made by an intra-articular injection of local anesthetic with or without steroids. Based on pooled data from multiple studies, even with three provocative examination maneuvers being positive, the likelihood of at least 75% temporary improvement following an injection is not statistically significant compared with those who respond to the injection based on the location of the pain alone.10
Figure 1 Examination maneuvers for the diagnosis of sacroiliac joint dysfunction. A, FABER or Patrick’s test; B, Gaenslen test. |
There is additionally significant crossover in the presentation of cervical symptoms and upper extremity symptoms. Shoulder pain can overlap with C4, C5, and C6 radiculopathies, depending on the pattern. An examination of the shoulder should include provocative tests and strength testing, particularly of the rotator cuff musculature. Rotator cuff tears have been shown to be accurately diagnosed through a combination of physical examination tests. The Jobe or “empty can” test, performed with the arm resisted while abducted to 90° and internally rotated; the lift-off test, performed with the dorsum of the wrist and arm placed upon the lumbar region above the waist as the patient lifts the forearm posteriorly away from the back; and comparison of the external rotation strength of the affected to the unaffected side together allow for determination of the likelihood of a rotator cuff tear being present.11 Additional tests should be performed for labral pathology, adhesive capsulitis, impingement, and biceps tendinopathy.