Lumbosacral evoked potentials (LSEPs) and cortical somatosensory evoked potentials (SEPs) in patients with lesions of the conus medullaris and cauda equina

Evoked potentials from unilateral stimulation of the posterior tibial nerve at the knee were recorded over the spinous processes S1, L4, L2, T12 and from the 'lower extremity' portion of the sensory cortex (Cz) in 29 patients who exhibited clinical and electromyographic signs of conus medullaris or cauda equina lesions. Simultaneous recording of the lumbosacral evoked potentials (LSEPs) and cortical somatosensory evoked potentials (SEPs) permitted evaluation of the relative effectiveness of the peripheral stimulus in eliciting responses in the lumbosacral segments of the spinal cord and in the cortex of the brain. In patients with cauda equina lesion, each major component of LSEP can be absent or the peak can have a reduced amplitude and a prolonged latency. The degree of impairment of the LSEP runs in parallel to the degree of severeness of the cauda equina lesion. The recording of LSEP responses with surface electrodes represents a reliable test for the detection of mild cauda equina abnormalities, but the surface recording technique is not sensitive enough to differentiate between severe incomplete and severe complete cauda equina lesions. On the other hand, concurrent recording of responses evoked at lumbosacral and cortical levels by the same stimuli did detect instances in which the first-order afferents were capable of delivering an adequate volley of impulses to evoke a sizeable cortical response without evidence of an associated postsynaptic response in the spinal cord. Such findings are good evidence of a problem localized in the gray matter of the spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pacinioma of the cauda equina

Lesions composed of Pacinian corpuscles or showing Pacinian corpuscle differentiation have usually been described in relation to benign tumours of the peripheral nervous system or reactive hyperplastic processes. On the other hand, mature Pacinian corpuscles have occasionally been detected as part of intraspinal lumbosacral lipomas, a rare developmental anomaly usually associated with spina bifida. A lesion of the cauda equina composed of numerous mature Pacinian corpuscles and nerve fascicles embedded in adipose tissue in association with spina bifida occulta is described in a 5-month-old male with a sacral red papula. Magnetic resonance imaging (MRI) revealed a cord-like mass in the region of the cauda equina, presumably connected to the subcutis. With the exception of a low lying, tethered spinal cord, there was no neurological deficit and the range of motor development was normal. In March 2005, at 17 months, surgery was carried out. A cord of yellow tissue was found running from the subcutis through the bone defect into the lumbosacral spinal canal. Intradurally, it ran parallel to the cauda equina, terminating at the conus medullaris. Fifteen months after the surgery the development of the child was normal. Only two similar cases have been reported so far. Due to their occurrence in the sacrococcygeal region and association with developmental anomalies, they have been regarded as malformations and the term Pacinioma has been suggested. Our case with clusters of Pacinian corpuscles may represent a rare variant of complex intraspinal lumbosacral lipomas, closely related to Paciniomas reported by Bale.     

Motor conduction velocity in the human spinal cord: slowed conduction in multiple sclerosis and radiation myelopathy.

Transcutaneous electrical stimulation of the central nervous system was used to measure motor conduction velocity in the human spinal cord in 21 subjects aged 22 to 75 years (mean 55 years), none of whom had neurological disease. The motor conduction velocity between the sixth cervical (C6) and first lumbar (L1) vertebral levels was 67.4 +/- 9.1 m/s. This probably represents conduction velocity in the corticospinal tracts. In these subjects the motor conduction velocity in the cauda equina, between the first lumbar (L1) and fourth lumbar (L4) vertebral levels, was 57.9 +/- 10.3 m/s. In four of five patients with multiple sclerosis, all with corticospinal signs in the legs, motor conduction velocity between C6 and L1 was slowed (41.8 +/- 16.8 m/s), but cauda equina conduction was normal (55.8 +/- 7.8 m/s). Similar slowing of spinal cord motor conduction was found in a patient with radiation myelopathy. This method should provide a relevant, simple clinical test in patients with spinal cord disease.     

Autonomic and motor neuron death is progressive and parallel in a lumbosacral ventral root avulsion model of cauda equina injury

Injuries to the cauda equina of the spinal cord result in autonomic and motor neuron dysfunction. We developed a rodent lumbosacral ventral root avulsion injury model of cauda equina injury to investigate the lesion effect in the spinal cord. We studied the retrograde effects of a unilateral L5-S2 ventral root avulsion on efferent preganglionic parasympathetic neurons (PPNs) and pelvic motoneurons in the L6 and S1 segments at 1, 2, 4, and 6 weeks postoperatively in the adult male rat. We used Fluoro-Gold-prelabeling techniques, immunohistochemistry, and quantitative stereologic analysis to show an injury-induced progressive and parallel death of PPNs and motoneurons. At 6 weeks after injury, only 22% of PPNs and 16% of motoneurons remained. Furthermore, of the neurons that survived at 6 weeks, the soma volume was reduced by 25% in PPNs and 50% in motoneurons. Choline acetyltransferase (ChAT) protein was expressed in only 30% of PPNs, but 80% of motoneurons remaining at 1 week postoperatively, suggesting early differential effects between these two neuronal types. However, all remaining PPNs and motoneurons were ChAT positive at 4 weeks postoperatively. Nuclear condensation and cleaved caspase-3 were detected in axotomized PPNs and motoneurons, suggesting apoptosis as a contributing mechanism of the neural death. We conclude that lumbosacral ventral root avulsions progressively deplete autonomic and motor neurons. The findings suggest that early neuroprotection will be an important consideration in future attempts of treating acute cauda equina injuries.     

Spinal evoked potential in the monkey

Computer-averaged evoked potential responses (EPs) to stimulation of the sciatic nerve and cervical spinal cord were recorded from the dura and skin over the cauda equina and spinal cord in seven monkeys, three with chronic spinal cord lesions. Sciatic EPs consisted of predominantly negative triphasic propagated potentials recorded at all spinal levels and greatest in amplitude over the cauda equina and caudal spinal cord. The conduction velocity of this EP was faster over the cauda equina and rostral spinal cord than over caudal cord segments. Triphasic potentials were succeeded by small negative potentials over the cauda equina and larger negative potentials over the lumbar enlargement. Sciatic EPs over the upper lumbar and thoracic cord were more sensitive to asphyxia than the initial triphasic potentials recorded over cauda equina and caudal cord but resisted changes from increasing the rate of stimulation up to 100 per second. Propagated thoracic EPs were preceded by nonpropagated potentials. The longer latency negative potentials occurring locally over the cauda equina and lower lumbar enlargement were abolished at levels of asphyxia and were attenuated at rates of stimulation that did not affect the preceding triphasic potentials. Following complete spinal cord transection, nonpropagated sciatic EPs were recorded in leads rostral to the section. In preparations with chronic partial cord hemisection involving dorsal and lateral quadrants, ipsilateral sciatic EPs had increased latency, reduced amplitude, and poor definition in the vicinity of and rostral to the lesion. Direct cervical cord stimulation elicited caudally propagated potentials which were followed by large, broad potentials over the lumbar enlargement.     

Sexual dysfunction after spinal cord or cauda equina lesions

In the neurological follow-up 68 patients with a history of spinal cord or cauda lesions of different aetiology and in different stages of regression were examined and interviewed concerning pre- and postmorbid sexual function. As to sexual dysfunction there was no difference between men and women. There was little relationship between the patients' motor function and their present sexual activity. On the other hand there was a statistically significant relationship between bladder dysfunction and sexual dysfunction. In elderly patients sexual activity was often reduced and also in cases of complete neurological restitution. Stability of the patients' marriage was as in the population on the whole. It is concluded that not only young patients, but also elderly ones, had a need for sexual rehabilitation after treatment for spinal cord or cauda equina lesion.     

Cauda equina syndrome due to recurrent malignant lymphoma of the spinal cord. A case report]

A 50-year-old man noticed a mass in the right cervical region and presented to our hospital. He underwent biopsy of a cervical lymph node, which revealed non-Hodgkin's lymphoma (diffuse large B cell, lymphoblastic type) histologically. He was treated with chemotherapy (CHOP) and radiation, and achieved complete remission. Two months later, he was admitted because of distal pain and extensive numbness of the lower limb as well as weakness of the left leg. Lumbar MRI showed an area of abnormal intensity in the cauda equina. Cytological examination of cerebrospinal fluid showed class V (lymphoma cells), so he was diagnosed as having recurrent malignant lymphoma of the spinal cord. He was treated with intrathecal chemotherapy and irradiation. After the treatment the mass in the cauda equina disappeared and the neurological symptoms in his legs resolved. It is rare for malignant lymphoma to recur in the spinal cord, particularly the cauda equina. It is well known that cauda equina syndrome can be caused by vertebral lesions and primary spinal cord tumors, but it is also necessary to keep malignant lymphoma of the cauda equina in mind.     

Delayed myeloradiculopathy produced by spinal X-irradiation in the rat

Rats were subjected to 3,500 r of X-irradiation in a single dose while breathing oxygen at 1 atm pressure. Comparison was made between the delayed effects of irradiating thoracic, lumbar, and the cauda equina fields. The lumbar field involved the alpha-motoneurons and spinal roots supplying the sciatic nerve, while the cauda equina field involved these spinal roots but spared the alpha-motoneurons in the spinal cord.Thoracic irradiation produced paraplegia after an interval of 127–150 days. In the irradiated zone, the spinal cord was severely damaged, but the thoracic spinal roots were spared.Lumbar irradiation produced paraplegia after an interval of 83–211 days. In the irradiated zone, the alpha-motoneurons were largely spared, the spinal cord showed mild to moderate white matter damage, but the most severe damage was of the lumbosacral spinal roots. The posterior roots were more affected than the anterior. In longer interval cases the degeneration of the roots appeared to be due to focal devitalization. Evidence is advanced that root degeneration had been progressing for at least 4 weeks before the onset of paraplegia.In the cauda equina series the lumbosacral spinal root changes were similar to those in the lumbar series.This study indicates that different levels of the neuraxis have different degrees of susceptibility to X-irradiation. The thoracic cord appears more susceptible than the lumbosacral; the lumbosacral roots appear more susceptible than the thoracic; the posterior roots are more susceptible than the anterior. These findings may have relevance to the study of radiation damage in man, even though the dose schedule used in this experimental study differs greatly from that used for radiotherapy.     

A clinical syndrome of rostral and caudal spinal injury: neurological, neurophysiological and urodynamic evidence for occult sacral lesion.

Patients with spinal cord injury show upper motor neuron dysfunction below the level of the lesion. Some patients with cervical and high thoracic injuries show unexpected lower leg atrophy and ankle jerk abnormalities together with persistence of urinary retention. Clinical, neurophysiological and urodynamic findings in 130 patients with cervical and thoracic injuries showed that 18 patients had additional lumbosacral dysfunction. Three patients had radiological findings demonstrating a second lesion of the lower spine. The remaining 15 patients, however, did not have any obvious bony lesion to account for the lumbosacral dysfunction. Atypical neurological findings, abnormal neurophysiological testing and aberrant detrusor behaviour were the essence of the occult lumbosacral dysfunction in cervical and thoracic spinal cord injury patients. Recognition of the presence of a double lesion was important for care of the neuropathic bladder and pain in addition to understanding the unexpected clinical signs.     

A case of post-irradiation lumbosacral radiculopathy successfully treated with corticosteroid and warfarin]

A 33-year-old man underwent post-operative radiation therapy for the left testicular anaplastic seminoma. One year later, the patient developed muscle weakness and sensory disturbance in the left lower extremity, and muscle weakness in the right lower extremity. MRI demonstrated linear and focal gadolinium (Gd) enhancement of the anterior portion of the lumbosacral roots within the cauda equina. The neurological symptoms improved after administration of corticosteroid and warfarin. Radiation myelopathy of this type was classified as "selective anterior horn cell injury or amyotrophy" by Reagan, and the site of the lesion was considered to be the lower motor neurons. However, based on the clinical and MRI findings, we proposed that the disease process was injury to the spinal nerve roots rather than the lower motor neurons. Recent neuropathological studies of this syndrome have demonstrated degeneration of the proximal spinal nerve roots. We consider that primary lesions of this syndrome occur in spinal nerve roots rather than in lower motor neurons, and "lumbosacral radiculopathy" is a more appropriate term for this condition.     

RADIATION MYELOPATHY OF THE LUMBO-SACRAL SPINAL CORD

The clinical findings in four cases of radiation injury to the lumbosacral spinal cord and cauda equina, occurring after radiotherapy of malignant testicular tumours with radiation doses of 1597–1670 ret, are reported. The main feature in each case was a flaccid paraparesis, without sensory loss in three cases, while one patient presented a doubtful sensory deficit. Symptoms of sphincter dysfunction were absent. In all cases the symptoms caused a marked and persistent incapacity. It is suggested that the principal site of radiation injury is the proximal parts of the lower motor neuron.     

Intradural extramedullary tumor of lower spinal cord in a 89-year-old man with cervical spondylosis and lumbar spondylolisthesis

A 89-year-old man was admitted because of slowly progressive gait disturbance during these several years. Neurological examination revealed paraparesis with bilateral sensory disturbance in the lower extremities, more severely on the left side. Vibration sense was almost completely disturbed under the level of bilateral crista iliaca. Deep tendon reflexes decreased in the lower extremities. No urinary incontinence was observed. The narrow spinal canal and cervical spondylosis were seen at the C 5-6 level, showing the anterior-posterior distance of 10 mm. Computed tomography of the lumbar spine showed spondylolisthesis between the level 4 and 5. CSF showed high protein concentration (300 mg/dl), whereas normal cell counts. These findings suggested the following two possibilities; cervical myelopathy associated with the disturbance of the cauda equina due to lumbar spondylolisthesis, or the disturbance at the lower thoracic or upper lumbar level of spinal cord. The spinal MRI revealed the irregular mass lesion in the lower spinal cord at the level of spine Th 11-12 on T2 weighted images, with enhancement by Gd-DTPA on T1 weighted images. These MRI findings suggested the intradural extramedullary tumor, such as benign neurinoma or meningioma. No clear cut lesions were found at the cervical spinal cord or at the cauda equina. MRI was useful for the diagnosis of sites and lesions of spinal cord in the present case, whose neurological signs and symptoms could be explained by the coexistent cervical spondylosis and lumbar spondylolisthesis.     

Somatosensory evoked potentials after multisegmental lower limb stimulation in focal lesions of the lumbosacral spinal cord

OBJECTIVES: Recording techniques permit the separate analysis of the response from cauda equina roots and the spinal potential that is probably generated by the activation of dorsal horn cells. To improve the functional assessment of focal lesions of the lumbosacral cord, lower limb somatosensory evoked potentials (SEPs) were measured by multisegmental stimulation. METHODS: Common peroneal and tibial nerves SEPs were recorded in 14 patients in whom MRI demonstrated compressive cord damage ranging from T9 to L1 levels. SEPs were recorded in each patient at the lumbar level (cauda equina response), lower thoracic level (spinal response), and from the scalp (cortical response). RESULTS: Abnormalities in spinal response occurred in 50% and 70% of tibial and common peroneal nerve SEPs respectively; these findings were well explained by the radiological compression level, involving in most of the patients lumbar rather than sacral myelomeres. The SEPs were often more effective than the clinical examination in showing the actual extension of damage. CONCLUSIONS: The recording of spinal SEPs after multisegmental lower limb stimulation proved useful in assessing cord dysfunction and determining the cord levels mainly involved by the compression.     

Saddle sensation is preserved in a few patients with cauda equina or conus medullaris lesions1

Although saddle sensory deficit seems the most useful clinical sign in the diagnosis of a cauda equina or conus medullaris lesion, findings of previous studies were controversial. The aim of the present study was to try to resolve this issue. The data from the author's series of patients with clinical, electrodiagnostic and radiological findings compatible with a cauda equina lesion were reviewed. Of the 117 patients in the series, 11 (10 men) did not have a saddle sensory deficit. These 11 patients had less severe sacral dysfunction than the others, and none of them needed urgent surgical intervention. They all had electromyographic (EMG) signs of a significant motor fibre lesion, and in seven men the sacral (penilo‐cavernosus) reflex was clinically abnormal. The study revealed normal saddle sensation in approximately 10% of patients with cauda equina or conus medullaris lesions. Dissociation between preserved touch sensation and abnormal EMG findings, as well as dissociation between preserved touch sensation and a non‐elicitable penilo‐cavernosus reflex might be explained by preservation of the thinner sensory nerve fibres, which are more resistant to compression. Although, saddle sensory loss seems to identify patients who might benefit from urgent spinal imaging and surgery, further diagnostic evaluation is also indicated in patients with normal saddle sensation, particularly due to the increased frequency of spinal tumours found in this subgroup.     

椎管内圆锥马尾区畸胎瘤的治疗

目的 总结椎管内圆锥马尾区畸胎瘤的临床特点和治疗经验。方法 回顾性分析1997年8月至2017年7月手术治疗的51例椎管内圆锥马尾区畸胎瘤的临床资料。结果 肿瘤的囊性部分全切除46例,次全切除加囊壁电灼5例;肿瘤实性部分全切除5例,次全切除20例,大部切除26例。51例术后病理检查均为成熟性囊性畸胎瘤。术后发生脑脊液漏3例、泌尿系感染5例,均治愈。32例疼痛中,24例术后疼痛缓解或消失,8例无变化。12例运动障碍中,7例术后肌力提高1~3级,4例无变化,1例肌力下降。7例括约肌功能障碍中,4例改善,3例无变化。51例术后随访6个月~19年,平均7.8年,随访超过5年27例。按McCormick分级标准,脊髓功能好转39例,不变11例,恶化1例。随访期间,未见肿瘤复发。结论 椎管内畸胎瘤多分布于脊髓圆锥马尾区,以慢性脊髓及神经压迫为表现。手术应在显微镜下,尽量全切肿瘤的囊性部分,如有囊壁残留应电灼防止复发,对肿瘤的实性部分应在避免脊髓损伤情况下,尽量切除减压,手术疗效满意。     

Slowed motor conduction in lumbosacral nerve roots in cauda equina lesions: a new diagnostic technique.

New techniques have been developed for the electrophysiological assessment of patients with suspected cauda equina lesions using transcutaneous spinal stimulation (500-1500 V: time constant 50 microseconds) to measure motor latencies to the external and sphincter and puborectalis muscles from L1 and L4 vertebral levels. These latencies represent motor conduction in the S3 and S4 motor roots of the cauda equina between these levels. Similarly motor latencies can be recorded from spinal stimulation to the anterior tibial muscles (L4 and L5 motor roots). Transrectal stimulation of the pudendal nerves is used to measure the pudendal nerve terminal motor latency. In 32 control subjects, matched for age and sex, mean motor latencies from L1 and L4 spinal stimulation were 5.5 +/- 0.4 ms and 4.4 +/- 0.4 ms (mean + SD). In the 10 patients with cauda equina disease including ependymoma, spinal stenosis, arachnoiditis and trauma, these latencies were 7.2 +/- 0.8 ms and 4.6 +/- 0.9 ms, a significant increase in the L1 latency. The L1/L4 latency ratios to the puborectalis muscle were 1.36 +/- 0.09 in control subjects and 1.72 +/- 0.13 in cauda equina patients. Pudendal nerve terminal motor latencies were normal in eight of the 10 patients with cauda equina disease. The single fibre EMG fibre density in the external and sphincter muscle (normal, 1.5 +/- 0.16) was increased in patients with cauda equina lesions (1.73 +/- 0.28), but was increased more than two standard deviations from the mean only in three patients. This increase in fibre density was not of diagnostic value since it was also found in two of the four patients with low back pain. Slowing of motor conduction in the cauda equina is thus a useful indication of damage to these intraspinal motor roots. These investigations can be used in the selection of patients for myelography, and to follow progress in patients managed conservatively.     

Postradiation lower motor neuron syndrome: case series and literature review

A variety of neurological syndromes has been described after irradiation of the distal spinal cord and cauda equina, mainly as treatment for testicular cancer and lymphoma. One of these syndromes is a rare lower motor neuron syndrome, manifested by flaccid paraparesis. Medical files of patients with postradiation lower motor neuron syndrome treated in our neuromuscular clinic from 2005 to 2012 were reviewed. The diagnosis was based on past irradiation of the distal spinal cord and cauda equina, slowly progressive lower limb weakness, characteristic electrophysiological studies, and no alternative diagnosis. In addition, a systematic review of the literature on similar cases was performed using PUBMED. We identified five patients with postradiation lower motor neuron syndrome in our clinic charts. Three of them were irradiated due to seminoma, and the other two due to lymphoma. 45 additional similar cases were found in a literature search, mainly male (89 %), with testicular cancer (67 %), irradiated at mean age of 33 years, with an average irradiation dose of 5,225 cGy (range 3,000–14,600), and a latency period between irradiation and symptoms onset ranging from 3 months to 27 years (average 9 years). Magnetic resonance imaging was done only in few, showing gadolinium enhancement of the cauda equina in close to half of them (7/16). Our patients and those previously described in the literature form a distinct clinical and electrophysiological syndrome that might be more frequent then previously expected, and should be not overlooked.     

吉兰-巴雷综合征的MRI诊断

目的 分析吉兰-巴雷综合征(OBS)患者的MRI扫描特征和限度. 方法对15例GBS患者(急性14例、慢性1例)行MRI平扫和增强后脂肪抑制TIWI扫描,观察椎管内周围神经的MRI表现及其与临床特征的关系.结果 MRI平扫显示8例急性患者马尾神经不同程度的增粗,T1WI为中等信号,T2W1为等或略高信号,1例慢性患者全脊椎的脊神经和马尾神经增粗.增强扫描显示14例急性患者T<,8>以下出现部分脊神经和马尾神经不同程度的增粗、强化,其中2例伴有部分颈脊神经增粗、强化,2例伴有部分颅神经增粗、强化.1例慢性患者全脊椎的脊神经、马尾神经和部分颅神经增粗、强化;全部患者出现双下肢乏力,其中双下肢瘫痪9例,MRI增强扫描均显示马尾神经明显强化(100%);双上肢乏力7例,MRI阳性3例(43%);颅神经功能障碍6例,MRI阳性3例(50%).结论 MRI可以敏感检测GBS患者的马尾神经病变,但颈神经和颅神经受累易漏诊.     

Bilateral vs. unilateral electromyographic examination of the external anal sphincter muscle.

AIM OF THE STUDY: In patients with cauda equina or conus medullaris lesions, bilateral electromyographic (EMG) examination of the subcutaneous external anal sphincter (EAS) muscles has been suggested. In spite of its circular shape, EAS should be considered as two separate semicircular muscles. The aim of the present study was to test the hypothesis that information obtained by bilateral examination of the EAS muscle outweighs inconvenience due to additional needle insertions. PATIENTS AND METHODS: A group of 67 patients with clinical and radiological data supportive of cauda equina or conus medullaris lesion was studied. From the subcutaneous EAS muscles motor unit potentials (MUPs) were sampled by the standard concentric EMG needle electrode, and an advanced EMG system with template operated multi-MUP analysis. Severity of EMG abnormalities was determined, and compared in 48 pairs of the left/right subcutaneous EAS muscles. RESULTS: In 18 patients, bilateral EMG abnormalities were found, in five of them asymmetry of involvement was demonstrated. Unilateral MUP abnormalities were found in 22 patients. The sensitivity of unilateral EMG analysis was 57% and of bilateral examination, 83%. CONCLUSION: In patients with suspected cauda equina lesions, as a rule, bilateral EMG of the subcutaneous EAS muscle is recommended.     

A forty-five-years-old woman suffered from Sj?gren syndrome with progressive tetraparesis]

We herein report the finding of a 45-year-old woman suffered from Sj?gren syndrome with progressive tetraparesis, who later developed systemic muscle atrophy and respiratory failure with a one-year clinical history. Neurological examinations revealed progressive tetraparesis with absent deep tendon reflexes, whereas no upper motor neuron signs were observed. The motor and sensory nerve conduction velocity and sensory nerve action potential (SNAP) were both completely normal, but the prolongation of distal motor latency in the median nerve and a decrease in the compound muscle action potential (CMAP) amplitude were observed. We ascertained that a spontaneous discharge was detected in her upper and lower limbs on electromyography (EMG). Her neurological findings as well as the EMG findings closely correlated with those of motor neuron disease; however, she showed a motor paralytic bladder and also demonstrated a serum antibody reaction with 50 kDa spinal cord protein of the rat. A lumbar MR image showed an increased signal intensity of the cauda equina on a gadolinium-enhanced T1 weighted image. We consider the immune-mediated impairment of the motor nerve associated with Sj?gren syndrome to be the cardinal pathogenesis of the present patient, even though treatment with oral corticosteroids did not ameliorate her symptoms.