History
Establishing a diagnosis of lumbosacral facet syndrome is difficult because the findings are nonspecific and correlation between the history and physical examination findings is poor. However, obtaining a detailed history and performing a physical examination help rule out other entities and assist with guiding the examiner in establishing the diagnosis of Z-joint–mediated LBP.
Although no single sign or symptom is diagnostic, Jackson et al demonstrated that the combination of the following 7 factors was significantly correlated with pain relief from an intra-articular Z-joint injection [9] :
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Older age
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Previous history of LBP
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Normal gait
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Maximal pain with extension from a fully flexed position
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The absence of leg pain
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The absence of muscle spasm
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The absence of exacerbation with a Valsalva maneuver
A basic demographic history should be taken. In particular, because most Z-joint pain is related to degenerative changes, older age may be related to Z-joint pathology.
The basic history should include a temporal account of the symptoms, a complete description of the problem, and a discussion of the associated activities that cause or alleviate the pain. The patient should describe the location of the pain; state whether it is isolated or radiating; and relate its intensity, character, and frequency. Red flags (ie, symptoms or signs that stand out as highly suggestive) that should be seriously scrutinized include the presence of unexplained weight loss, fever, and chills. The clinician should also obtain a history of any previous treatments (eg, injections, medications, therapy) and whether they were successful.
Z-joint pathology should be considered if the patient describes nonspecific LBP with a deep and achy quality that is usually localized to a unilateral or bilateral paravertebral area.
Provocative injections of the Z-joints have been used to create a sclerotomal map of the Z-joint’s pain referral pattern. Based on these studies, the common referral areas for Z-joint–mediated pain are flank pain, buttock pain (often extending into the posterior thigh, but rarely below the knee), pain overlying the iliac crests, and pain radiating into the groin. However, this pain pattern is not consistently reported in patients with Z-joint pain as confirmed by diagnostic intra-articular Z-joint injections. Therefore, this sclerotomal representation of the Z-joint is only suggestive, not diagnostic.
The pain is often exacerbated by twisting the back, by stretching, by lateral bending, and in the presence of a torsional load. Some patients describe their pain as worse in the morning, aggravated by rest and hyperextension, and relieved by repeated motion. Often, this lumbosacral facet syndrome may occur after an acute injury (eg, extension and rotation of the spine), or it may be chronic in nature.
Unlike other lumbar spine pathologies such as disc herniation, Z-joint–mediated pain likely will not worsen with an increase in intra-abdominal and thoracic pressure. Therefore, worsening of pain with coughing, laughing, or a Valsalva maneuver is suggestive that the Z-joint is not the primary pain generator.
Physical Examination
No historical findings or examination maneuver is unique or specific to Z-joint–mediated LBP. In fact, some authors report up to a 45% false-positive rate when the physical examination findings are correlated to diagnostic medial branch blocks of the posterior rami. Many clinicians agree that correlating history or physical examination findings with pain emanating from the Z-joint is a challenge.
Patients with Z-joint–mediated LBP usually have nonspecific history and physical examination findings. An in-depth evaluation of the neurologic and musculoskeletal systems helps exclude other diagnoses and guides the clinician to possible Z-joint pathology.
Inspection
Inspection should include an evaluation of paraspinal muscle fullness or asymmetry, increase or decrease in lumbar lordosis, muscle atrophy, or posture asymmetry.
Patients with chronic facet syndrome may have flattening of the lumbar lordosis and rotation or lateral bending at the sacroiliac joint or thoracolumbar area.
Palpation
The examiner should palpate along the paravertebral regions and directly over the transverse processes because the Z-joints are not truly palpable. This is performed in an attempt to localize and reproduce any point tenderness, which is usually present with Z-joint–mediated pain.
In some cases, Z-joint–mediated pain may radiate to the gluteal or posterior thigh regions.
Range of motion
Range of motion should be assessed through flexion, extension, lateral bending, and rotation.
With Z-joint–mediated LBP, pain is often increased with hyperextension or rotation of the lumbar spine, and it might be either focal or radiating.
Flexibility
Inflexibility of the pelvic musculature can directly impact the mechanics of the lumbosacral spine.
With Z-joint pathology, the clinician may find an abnormal pelvic tilt and rotation of the hip secondary to tight hamstrings, hip rotators, and the quadratus, but these findings are nonspecific and can be found in patients with other causes of LBP.
Sensory examination
Sensory examination (ie, light touch and pinprick in a dermatomal distribution) findings are usually normal in persons with Z-joint pathology.
Muscle stretch reflexes
Patients with Z-joint–mediated LBP usually have normal muscle stretch reflexes. Radicular findings are usually absent unless the patient has nerve root impingement from bony overgrowth or a synovial cyst.
Side-to-side asymmetry should lead one to consider possible nerve root impingement.
Muscle strength
Manual muscle testing is important to determine whether weakness is present and whether the distribution of weakness corresponds to a single root, multiple roots, or a peripheral nerve or plexus.
Typically, manual muscle testing results are normal in persons with Z-joint pathology; however, subtle weakness of the muscles of the pelvic girdle may contribute to pelvic tilt abnormalities. This subtle weakness may be appreciated with trunk, pelvic, and lower-extremity extension asymmetry.
Straight leg – raise test
This maneuver is usually normal for Z-joint–mediated pain. However, if Z-joint hypertrophy or a synovial cyst encroaches on the intervertebral foramen, causing nerve root impingement, this maneuver may elicit a positive response.
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Dorsal ramus innervation (medial and lateral branches). MAL23 = mamillo-accessory ligament bridging the mamillary and accessory processes of L2 and L3; Z-joint = zygapophyseal joint.
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Mamillary process anatomy.
