Objective: The differences in symptoms of spinal meningiomas have rarely been discussed from the perspective of tumor characteristics. The main purpose of this paper was to define the differences, if any, in symptoms in patients with spinal meningiomas with respect to tumor size, location, and degree of spinal cord compression. The authors also sought the threshold of spinal cord compression that causes motor weakness.
Methods: The authors conducted a retrospective study of 53 cases of spinal meningiomas that were surgically treated from 2013 to 2018. Symptoms related to the tumor were classified as motor weakness, sensory disturbance, pain, and bowel/bladder dysfunction. Based on MR images, tumor location was classified by spinal level and by its attachment to the dura mater. Tumor dimensions were also measured. Occupation ratios of the tumors to the spinal canal and degree of spinal cord flattening were sought from the axial MR images that showed the highest degree of spinal cord compression.
Results: Motor weakness and sensory disturbance were significantly more common in thoracic spine meningiomas than in cervical spine meningiomas (p < 0.001 and p = 0.013, respectively), while pain was more common in meningiomas at the craniovertebral junction (p < 0.001). The attachment, height, width, depth, and volume of the tumor showed no significant difference irrespective of the presence or absence of each symptom. In cases of motor weakness and sensory disturbance, occupation ratios and spinal cord flattening ratios were significantly larger. However, these ratios were significantly smaller in the presence of pain. Multivariate logistic regression analysis revealed that occupation ratio independently contributed to motor weakness (OR 1.14, p = 0.035) and pain (OR 0.925, p = 0.034). Receiver operating characteristic curve analysis suggested that occupation ratio with a value of 63.678% is the threshold for the tumor to cause motor weakness.
Conclusions: The study showed the difference in clinical presentation of spinal meningiomas by spinal level, occupation ratio, and spinal cord flattening ratio. An occupation ratio of approximately 64% could be utilized as the threshold value of tumor growth to cause motor weakness. Tumor growth in the cervical spine might cause pain symptoms before causing motor weakness. The relationship between the tumor and its symptomatology should be discussed with respect to tumor size relative to the surrounding spinal canal.
Keywords: BBD = bowel/bladder dysfunction; CVJ = craniovertebral junction; OPLL = ossification of the posterior longitudinal ligament; occupation ratio; oncology; spinal level; spinal meningioma; tumor dimension.