The Art of Diagnosis in the Cervical Spine

Novel MRI signs of ruptured disc in the cervical spine with intraoperative comparisons

OBJECTIVES

To evaluate the diagnostic performance of two novel MRI signs for extruded disc (ED) and uncontained ED (ruptured disc, RD) in the cervical spine using intraoperative findings as reference.

METHODS

This retrospective study included patients who underwent cervical spine MRI and surgery for disc pathology with intraoperative confirmation of RD from September 1, 2016, to January 31, 2021. Two radiologists determined whether the disc was extruded or ruptured with and without the aid of two novel MRI signs suggesting RD (sign 1: blurred margin of the disc; sign 2: mushroom-shaped disc). The diagnostic performance was analyzed using surgical findings as reference. Intra- and interobserver agreements were measured for each MRI sign.

RESULTS

A total of 91 patients totaling 131 discs were enrolled (mean age: 56.02 ± 12.93; range: 26-88; 62 men and 29 women), of whom 62 were surgically confirmed with RD. When the diagnosis was based exclusively on existing ED definitions, ED was diagnosed with 62.9-79.0% sensitivity and 80.2% accuracy, whereas RD was diagnosed with 35.5-45.2% sensitivity and 67.9-71.0% accuracy. However, when the two novel MRI signs were used as an aid in the diagnosis, ED was diagnosed with 95.2-96.8% sensitivity and 84.0-88.5% accuracy, while RD was diagnosed with 95.2-96.8% sensitivity and 84.0-89.3% accuracy. Intra- and interobserver agreement was substantial (k = 00.77-0.86, 0.69-0.79, respectively, p < 0.001).

CONCLUSIONS

The detection of two novel MRI signs on preoperative MRI can lead to a more accurate RD diagnosis.

KEY POINTS

• The diagnostic sensitivity of MRI for cervical ruptured disc is very low (about 35-45 %) using the standardized definition of lumbar disc nomenclature. • Two novel MRI signs can lead to a more accurate diagnosis of the surgically confirmed ruptured disc in the cervical spine. • These two novel MRI signs showed substantial intra-and interobserver reliabilities.

Reliability and Diagnostic Accuracy of Standard Dermatomes and Myotomes for Determining the Pathologic Level in Surgically Verified Patients With Cervical Radiculopathy

OBJECTIVE

This study aimed to investigate the reliability and diagnostic accuracy of typical dermatomes and myotomes for determining the pathologic level in surgically verified patients with cervical radiculopathy.

METHODS

Patients who underwent single-level surgery due to cervical radiculopathy with at least a 60% reduction in preoperative symptoms or recovery of muscle power after surgery were included. The observed clinical symptoms (pain, paresthesia, motor weakness) were compared to those of typical cervical dermatomes and myotomes.

RESULTS

Among the 227 patients reviewed, 142 (62.6%) had a standard dermatomal pattern, and 74 of 110 (67.3%) had a standard myotomal pattern. The myotome of C5/6 radiculopathy showed much more variance than those of other cervical segments. Among the patients with severe motor weakness (muscle strength ≤ grade 3 or obvious muscle atrophy), all those with involvement of root C5, C7, and C8 showed a typical pattern (C4/5: 13 of 13 patients, C6/7: 5 of 5 patients, C7/T1: 3 of 3 patients), while only 2 of the 6 patients (33.3%) with severe motor weakness caused by C5/6 radiculopathy fit the typical pattern.

CONCLUSION

Among various symptoms, cervical myotome is of great value in determining the pathological level. However, it should be noted that there is high variability in human dermatomes and myotomes, especially for motor weakness due to C6 root compression, which is more variable than others.

Importance of Differential Diagnosis of a Possible Brain Tumor in Patients with Cervical Radiculopathy

Lesions occurring simultaneously in the somatosensory or motor cortex of the brain and the cervical spine are rare. Brain tumors can cause similar symptoms to cervical lesions which can lead to confusion in treatment priorities. Moreover, if cervical disease is noticeably observed in radiologic findings of a patient complaining of cervical radiculopathy with non-specific electromyography results, it is common to no longer perform further evaluation. Here we introduce two cases where the cause of cervical radiculopathy was first considered to be the result of a degenerative cervical disease but was later discovered to be a result of a brain tumor.