Sudden post-traumatic sciatica caused by a thoracic spinal meningioma

Abstract

Spinal meningiomas usually present with slowly progressive symptoms of cord and root compression, while a sudden clinical onset is very rare. A 35-year-old previously symptom-free woman presented sudden right sciatica and weakness of her right leg following a fall with impact to her left foot. A neurological examination showed paresis of the right quadriceps, tibial and sural muscles, increased bilateral knee and ankle reflexes and positive Babinski sign. Magnetic resonance imaging (MRI) revealed the presence of a spinal T11 meningioma in the left postero-lateral compartment of the spinal canal; at this level, the spinal cord was displaced to the contralateral side with the conus in the normal position. At surgery, a meningioma with dural attachment of the left postero-lateral dural surface was removed. The intervention resulted in rapid remission of both pain and neurological deficits. Spinal meningiomas may exceptionally present with sudden pain and neurological deficits as result of tumour bleeding or post-traumatic injury of the already compressed nervous structures, both in normal patients and in those with conus displacement or tethered cord. In this case, the traumatic impact of the left foot was transmitted to the spine, resulting in stretching of the already compressed cord and of the contralateral lombosacral roots. This case suggests that low thoracic cord compression should be suspected in patients with post-traumatic radicular leg pain with normal lumbar spine MRI.

Introduction

Spinal meningiomas are benign and slow-growing tumours, usually occurring in young adults and elderly patients, particularly women. The mean duration of symptoms prior to diagnosis varies between one and two years,^1,2 but it has been reported to be even longer (15–20 years).¹ Local pain is often the initial manifestation, and it may precede symptoms and signs of cord compression by years.^3–5 Radicular pain can also occur due to nerve root compression as they exit the neural foramina, especially when the lesion develops laterally in the spinal canal.

Sudden clinical onset in the absence of prior spinal symptoms is a very rare event (only 2/140 [1.4%] spinal meningiomas in our surgical series). This may be due to tumour haemorrhage,⁶ cord compression by a concomitant spine trauma⁷ or tethering of the nerve roots and/or cord.⁴

We report a case of spinal meningioma of the low thoracic region, presenting as sudden post-traumatic right sciatica and right leg weakness, due to cord and root stretching.

Case report

A 35-year-old previously symptom-free woman was subjected to an accidental fall with impact on the heel of the left foot. Suddenly after the trauma, she complained of intense low-back pain referred to the right sciatic territory, followed by weakness of the right leg with difficulty in standing and walking. A computed tomography scan of the lumbar spine was negative. Medical therapy with corticosteroids resulted in mild pain improvement. Magnetic resonance imaging (MRI) of the thoracic and lumbar spine (Figure 1) showed a T11 homogeneously enhancing intradural extramedullary tumour located on the left postero-lateral compartment of the spinal canal; the spinal cord was displaced downward and on the right side. The conus medullaris was in its normal position.

Figure 1.

Preoperative magnetic resonance, sagittal post-contrast T1- (a) and T2-weighted sequences (b) and axial T1 sequence (c): spinal meningioma with posterior and mainly left location and anterior and right displacement of the spinal cord.

A neurological examination showed paresis of the right quadriceps femoris and of flexor and extensor muscles of the right foot, bilaterally increased knee and ankle reflexes and positive Babinski sign, with slight hypoesthaesia on the right leg.

At the point of surgery, a T11–T12 laminectomy was performed, and an intradural extramedullary meningioma with dural attachment to the left postero-lateral surface of the spinal dura was removed. On histopathological examination, the lesion resulted in an atypical (WHO II) meningioma (Ki-67 MIB-1 10–12%).

After surgery, low-back and right sciatic pain progressively disappeared. Physiotherapy resulted in rapid improvement of the right leg paresis with return to autonomous walking, although there was minimal residual ataxia. MRI of the thoracic spine (Figure 2) showed no residual tumour and no cord compression. At the last follow-up (five months after surgery), the patient was symptom-free.

Figure 2.

Postoperative magnetic resonance, sagittal T1-weighted sequence: good decompression of the spinal cord, and no residual tumour.

Discussion

Several pathological events, both traumatic and non-traumatic, may result in sudden clinical onset of spinal meningiomas. Among the possible mechanisms, subarachnoid or subdural bleeding is exceptional in the case of spinal meningiomas,⁶ while it is more frequent in hemangioblastomas,⁷ ependymomas and schwannomas.⁸ It may present with sudden back pain or with rapidly progressive neurological deficit. Another rare clinical presentation of spinal meningiomas is acute paraparesis as a result of vertebral traumatic compression fracture at the same level.⁹ Furthermore, stretching of the nervous structures due to anomalous movement of the spine is a well-recognised mechanism of sudden clinical presentation, albeit exceptional in patients with spinal meningiomas.^4,5 The mechanism underlying clinical symptomatology due to cord and root stretching changes according to the anatomical position of the conus and the absence or presence of tethered cord. In patients with tethered cord and the conus in the lower position, the symptoms may be caused even by minor trauma, sudden efforts, exaggerated bending of the back or pregnancy.^10,11

In individuals with the spinal cord in the normal position and no thickening of the filum terminalis, as happened in the present case, clinical symptoms usually occur in a late phase, thanks to adaptive compressibility of the cerebrospinal fluid and the adjacent vascular structures. Only when the compliance of these structures has been exceeded is the tumour compression directly transmitted to the spinal cord, resulting in neurological deficit. In these cases, the stretching of the cord and roots is exceptional, and it may occur only in particular circumstances as a consequence of significant direct or indirect trauma to the spinal column. Our patient was subjected to an accidental fall with the impact on the left foot. The trauma force was transmitted from the left leg to the spine, stretching the lower spinal cord and contralateral lumbosacral nerve roots that had already been compressed and displaced by the tumour. The presence of dentate ligaments, fixing the spinal cord to the walls of the dural sac, probably contributed to reduce the mobility of the nervous structures, making them more susceptible to stretching after trauma.

Conclusions

Although the sudden onset of sciatic pain after trauma usually suggests a lumbar or peripheral pathology, a low thoracic cord compression must be suspected when MRI of the lumbar spine is normal and objective neurological signs of spinal cord compression are evidenced.

Conflict of Interest

The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Funding

This work received no grant from any funding agency in the public, commercial or not-for-profit sectors.