The diagnosis and natural history of spinal cord arteriovenous malformations

The present study of 71 patients shows that the initial symptoms often cannot differentiate spinal cord arteriovenous malformation from other lesions causing cord dysfunction, but the picture at the time of presentation may suggest the diagnosis. Most patients are males with neurologic findings referable to the thoracolumbar area who present with gradually progressive pain, weadness, sensory distubance, and disturbance of micturition. Early impairment of micturition may help suggest this lesion because it is less likely to be an early complaint in patients with disk disease or tumor affecting the spinal cord. Symptoms occasionally vary with posture and exercise and menses. Most commonly there are combined upper motor neuron and lower motor neuron manifestations with nonradicular sensory deficit. The cerebrospinal fluid is abnormal in more than 75% of cases. The myelogram is positivie in 75 to 90% of cases and the angiogram is almost always diagnostic.     

Correlations between clinical deficits, motor and sensory evoked potentials and radiologic aspects of MRI in malformative syringomyelia. 27 Cases

Twenty-seven patients (15 males, 12 females, age range: 16-66 years) were admitted for malformative syringomyelia diagnosed on MRI with measures of syrinx extending and transverse diameter. Posterior tibial somatosensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms. PT SEP proved to be more sensitive than M SEP. MEP abnormalities were very frequent (87% of the cases), even without clinical motor deficits. Trigeminal SEP were more sensitive than BEAP which were not related to the presence of associated cranio-vertebral abnormalities. We found no significative relationship between clinical and radiological results. Moreover, there was a positive relationship between electrophysiological and radiological results: abnormal trigeminal SEP were detected in 85% of the patients with high cervical syringomyelia. In all cases, trigeminal SEP and MEP should be done in association with M and PT SEP as both of them detect subclinical evidence of spinal cord dysfunction in syringomyelia.     

The kininogen gene family in obstructive uropathy

Because many patients present themselves for treatment with both craniofacial and craniocervical pain, 2 questions arise: (1) What are the sensory and motor consequences of dysfunction in either of these areas on the other? (2) Do craniofacial and craniocervical pain have a similar cause? These questions formed the impetus for this review article. The phenomenon of concurrent pain in craniofacial and cervical structures is considered, and clinical reports and opinions are presented regarding theories of cervical-to-craniofacial and craniofacial-to-cervical pain referral. Because pain referral between these 2 areas requires anatomic and functional connectivity between trigeminally and cervically innervated structures, basic neurophysiologic and neuroanatomic literature is reviewed. The published data clearly demonstrate neurophysiologic and structural convergence of cervical sensory and muscle afferent inputs onto trigeminal subnucleus caudalis nociceptive and non-nociceptive neurons. Moreover, changes in metabolic activity and blood flow in the brainstem and cervical dorsal horn of the spinal cord in both monkeys and cats have been demonstrated after electric stimulation of the V1-innervated superior sagittal sinus. In conclusion, the animal experimental data support the findings of human empiric and experimental studies, which suggest that strong connectivity exists between trigeminal and cervical motor and sensory responses.     

Right sensory-motor syndrome as the presentation of a spontaneous cervico-thoracic epidural hematoma

INTRODUCTION: A spontaneous cervical epidural hematoma is an infrequent cause of cord compression. The commonest clinical presentations are with paraparesia and tetraparesia. Transient hemiparesia is very rare and a sensory-motor syndrome is exceptional. CLINICAL CASE: A 38 year old man had sudden onset of spontaneous interscapular vertebral pain with bilateral root radiation. A few minutes later he started to have weakness and sensory loss in his right limbs. On clinical examination there was pain on pressure over the spinal apophyses of the T4 and T5 vertebrae, hemiparesia and hemi-hypoalgesia of the right limbs. After ten hours this had all returned to normal. MRI of the cord showed an epidural hematoma extending from C6 to T2. Coagulation studies and spinal arteriography were normal. CONCLUSIONS: The sensory motor syndrome is an unusual form of presentation of a spontaneous cervico-thoracic epidural hematoma. Root pain is a symptom of great value for orientation of a syndrome which would otherwise seem to be of central origin. The explanation for this clinical findings may be compression of both lateral cord pathways due to their particular blood distribution. Regarding therapeutic approach, this should be conservative, with close observation to see whether it will resolve spontaneously in a short period of time.     

Significance of the BTA test in bladder cancer: a multicenter trial. BTA Study Group Japan

Complex regional pain syndrome (CRPS) is a progressive, chronic illness that is enigmatic because the mechanisms for its pathogenesis have yet to be determined. Syndromes synonymous with CRPS are reflex sympathetic dystrophy, reflex neurovascular dystrophy, causalgia, algoneurodystrophy, sympathetically maintained pain, clenched fist syndrome, and Sudek's syndrome. The diagnosis of CRPS is categorized into three stages: acute, dystrophic, and atrophic. CRPS is most often precipitated by peripheral trauma (crushing injuries, lacerations, fractures, sprains, burns, or surgery) to soft tissue or nerve complexes. The pathogenesis for CRPS has been speculated as being either a disease process of the peripheral nerves, a disease process of peripheral soft tissue, or a disease process of the spinal cord. Patients suffering from CRPS may be limited in their ability to function in a self-directed, independent fashion. A longitudinal study of CRPS on 1,348 patients revealed that 96% of the study subjects still suffer some pain and disability regardless of the duration of the disease or course of treatment. Although the primary etiology for CRPS is not clearly understood, key progress has been made in terms of establishing a psychological as well as therapeutic treatment plan once the diagnosis has been made.     

Efficacy of surgical treatment in traumatic central cord syndrome

BACKGROUND: Controversy surrounds the treatment of traumatic central cord syndrome (TCCS), as there are strong advocates for nonsurgical treatment for most patients. However, conservative treatment has been shown to yield a longer period of discomfort from pain and weakness in certain cases. METHODS: In a retrospective review of 114 patients presenting with acute or chronic TCCS from 1988-94, four different age groups were separately observed under different treatments. Motor and sensory recovery were assessed. RESULTS: Better results were achieved in younger patients, with or without radiographic abnormalities, and in patients with clinically correlated encroaching cord lesions who received early surgical decompression. CONCLUSIONS: Surgical intervention for TCCS must be addressed with careful clinical and radiographic survey. Removal of offending lesions in the subacute period results in significant motor and sensory improvement in short-term and long-term follow-up.     

Congenital tethered spinal cord syndrome in adults

OBJECT: The management of tethered spinal cord syndrome with onset of symptomatology occurring in adulthood remains controversial, although the necessity of early surgery in the pediatric tethered cord syndrome population is well established. To ascertain the results of surgery in adult patients with this anomaly, the authors undertook a retrospective review of 34 cases. METHODS: The authors studied the hospital records of 34 consecutive patients who presented in adulthood with tethered cord syndrome and conducted follow-up phone interviews with 28 of them. The population consisted of 12 men and 22 women, ranging in age from 18 to 70 years (mean 34 years). The most common presenting feature was pain, followed by weakness and incontinence. All patients underwent surgery. The most common operative findings were tight filum terminale, split cord malformation, and lipomyelomeningocele, paralleling those observed in pediatric studies. Long-term surgical results and patient outcome ratings were encouraging. After a mean clinical follow-up period of 4 years, significant improvement occurred in 22 of 27 patients presenting with pain, 13 of 27 patients with motor or sensory dysfunction, and 11 of 18 patients with bowel and bladder disturbance. In addition, telephone interviews were obtained after a period of 8.6 years. Twenty-two (79%) of 28 patients called the operation a long-term success; 21 (75%) of 28 patients believed that they had significant postoperative improvement (and not just stabilization) in pain and/or neurological function. Surgical complications were generally minor. Nineteen (86%) of 22 employed patients returned to work after surgery. Two (33%) of six patients who were not employed before surgery worked full time postoperatively. Only two of the 28 patients interviewed had received Workers' Compensation benefits; both of these had good outcomes and returned to work. CONCLUSIONS: Tethered spinal cord syndrome in adults is an uncommon entity that can become symptomatic. Although surgery in adults involves greater risk of neurological injury than in children, it is a low-risk procedure with encouraging results. Because neurological deficits are generally irreversible, early surgery is recommended.     

"Threshold-level" multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring

Numerous methods have been pursued to evaluate function in central motor pathways during surgery in the anesthetized patient. At this time, no standard has emerged, possibly because each of the methods described to date requires some degree of compromise and/or lacks sensitivity. OBJECT: The goal of this study was to develop and evaluate a protocol for intraoperative monitoring of spinal motor conduction that: 1) is safe; 2) is sensitive and specific to motor pathways; 3) provides immediate feedback; 4) is compatible with anesthesia requirements; 5) allows monitoring of spontaneous and/or nerve root stimulus-evoked electromyography; 6) requires little or no involvement of the surgical team; and 7) requires limited equipment beyond that routinely used for somatosensory evoked potential (SSEP) monitoring. Using a multipulse electrical stimulator designed for transcranial applications, the authors have developed a protocol that they term "threshold-level" multipulse transcranial electrical stimulation (TES). METHODS: Patients considered at high risk for postoperative deficit were studied. After anesthesia had been induced and the patient positioned, but prior to incision, "baseline" measures of SSEPs were obtained as well as the minimum (that is, threshold-level) TES voltage needed to evoke a motor response from each of the muscles being monitored. A brief, high-frequency pulse train (three pulses; 2-msec interpulse interval) was used for TES in all cases. Data (latency and amplitude for SSEP; threshold voltage for TES) were collected at different times throughout the surgical procedure. Postoperative neurological status, as judged by evaluation of sensory and motor status, was compared with intraoperative SSEP and TES findings for determination of the sensitivity and specificity of each electrophysiological monitoring technique. Of the 34 patients enrolled, 32 demonstrated TES-evoked responses in muscles innervated at levels caudal to the lesion when examined after anesthesia induction and positioning but prior to incision (that is, baseline). In contrast, baseline SSEPs could be resolved in only 25 of the 34 patients. During surgery, significant changes in SSEP waveforms were noted in 12 of these 25 patients, and 10 patients demonstrated changes in TES thresholds. Fifteen patients experienced varying degrees and durations of postoperative neurological deficit. Intraoperative changes in TES thresholds accurately predicted each instance of postoperative motor weakness without error, but failed to predict four instances of postoperative sensory deficit. Intraoperative SSEP monitoring was not 100% accurate in predicting postoperative sensory status and failed to predict five instances of postoperative motor deficit. As a result of intraoperative TES findings, the surgical plan was altered or otherwise influenced in six patients (roughly 15% of the sample population), possibly limiting the extent of postoperative motor deficit experienced by these patients. CONCLUSIONS: This novel method for intraoperative monitoring of spinal motor conduction appears to meet all of the goals outlined above. Although the risk of postoperative motor deficit is relatively low for the majority of spine surgeries (for example, a simple disc), high-risk procedures, such as tumor resection, correction of vascular abnormalities, and correction of major deformities, should benefit from the virtually immediate and accurate knowledge of spinal motor conduction provided by this new monitoring approach.     

Anatomical regeneration and behavioral recovery following crush injury of the trigeminal root in lamprey

In normal larval lamprey, bilateral application of horseradish peroxidase (HRP) to the dorsal part of the anterior oral hood labeled subpopulations of trigeminal components on both sides of the brain; peripherally projecting motoneurons, medullary dorsal cells (sensory), and spinal dorsal cells (sensory), as well as centrally projecting afferents in the trigeminal descending tracts. Following unilateral crush injury of the right trigeminal root, HRP labeling of sensory and motor trigeminal components on the right side gradually increased with increasing recovery time, between 2 weeks and 12 weeks postcrush (PC). Axons of trigeminal motoneurons appeared to exhibit robust regeneration, whereas restoration of projections in the descending trigeminal tract ipsilateral to the injury was incomplete. Control experiments indicated that motor and sensory axons from the intact side of the oral hood did not sprout across the midline to the denervated side. Several results suggested that regenerated trigeminal sensory fibers made synapses with brain neurons that have direct or indirect inputs to reticulospinal (RS) neurons. Following a unilateral crush injury of the right trigeminal root, escape behavior in response to stimulation of the right side of the oral hood gradually returned to normal. Muscle recordings at various recovery times confirmed that anatomical regeneration of trigeminal sensory axons was functional. In addition, at 8 or 12 weeks PC, brief stimulation of the oral hood ipsilateral or contralateral to the crush injury elicited synaptic responses in RS neurons on either side of the brain, similar to that in normal animals. In the lamprey, compensatory mechanisms probably allow recovery of behavioral function despite incomplete regeneration of trigeminal sensory axons within the central nervous system.     

Cellular delivery of neurotrophin-3 promotes corticospinal axonal growth and partial functional recovery after spinal cord injury

The injured adult mammalian spinal cord shows little spontaneous recovery after injury. In the present study, the contribution of projections in the dorsal half of the spinal cord to functional loss after adult spinal cord injury was examined, together with the effects of transgenic cellular delivery of neurotrophin-3 (NT-3) on morphological and functional disturbances. Adult rats underwent bilateral dorsal column spinal cord lesions that remove the dorsal corticospinal projections or underwent more extensive resections of the entire dorsal spinal cord bilaterally that remove corticospinal, rubrospinal, and cerulospinal projections. Long-lasting functional deficits were observed on a motor grid task requiring detailed integration of sensorimotor skills, but only in animals with dorsal hemisection lesions as opposed to dorsal column lesions. Syngenic primary rat fibroblasts genetically modified to produce NT-3 were then grafted to acute spinal cord dorsal hemisection lesion cavities. Up to 3 months later, significant partial functional recovery occurred in NT-3-grafted animals together with a significant increase in corticospinal axon growth at and distal to the injury site. These findings indicate that (1) several spinal pathways contribute to loss of motor function after spinal cord injury, (2) NT-3 is a neurotrophic factor for the injured corticospinal projection, and (3) functional deficits are partially ameliorated by local cellular delivery of NT-3. Lesions of the corticospinal projection may be necessary, but insufficient in isolation, to cause sensorimotor dysfunction after spinal cord injury in the rat.     

Pain associated with spinal cord injury

Management of pain after spinal cord injury remains a difficult clinical problem. In particular, neuropathic spinal cord injury pain, like other forms of deafferentation pain in which there is loss or modification of normal afferent sensory inputs, is notoriously resistant to currently available modes of treatment. Although there have been some advances in our understanding of spinal cord injury pain, the mechanisms of neuropathic spinal cord injury pain remain largely unknown and treatment is often ineffective. This review presents findings from recent publications that deal with the mechanisms and management of spinal cord injury pain.     

Clinical, neurodiagnostic, and MR findings in children with spinal and brain stem multiple sclerosis

PURPOSE: To describe the clinical, neurodiagnostic, and MR findings in seven children with brain stem and spinal multiple sclerosis. METHODS: Spinal or brain stem multiple sclerosis was diagnosed in seven children between 1986 and 1992. All patients had neurologic and MR examinations as well as neurodiagnostic testing, including spinal fluid analysis and brain stem and auditory evoked potentials. RESULTS: Three children had clinical findings and masslike lesions in the brain stem (two) or spinal cord (one) suggestive of neoplasm, which prompted biopsy (two) or radiation therapy (one). Five of six patients with spinal involvement had cord swelling with increased signal on T2-weighted images over at least three cord segments, and two children had essentially holocord involvement. Three children had normal cranial MR at presentation. CONCLUSIONS: Multiple sclerosis involvement of the brain stem and spinal cord may be associated with extensive swelling and MR signal changes suggestive of neoplasm without typical cerebral white matter abnormalities. Serial clinical and neuroimaging examinations may be necessary to make a definitive diagnosis of multiple sclerosis in children.     

Motor recovery following spinal cord injury associated with cervical spondylosis: a collaborative study

A prospective multicenter study was conducted within the National Model Spinal Cord Injury System program to examine neurological deficits and recovery patterns following spinal cord injury (SCI) in individuals with cervical spondylosis and without a spinal fracture. Nineteen patients were evaluated. Sixty-eight percent presented initially with motor incomplete lesions. Of those who presented with motor incomplete injuries at their initial examination, 69 percent had less deficit in the lower than in the upper extremities, indicative of a central cord syndrome. At follow-up, 12 subjects were unable to ambulate, four required assistance and three were able to ambulate independently. On the average, subjects doubled their initial Asia Motor Score (AMS) scores by one year following injury. Residual upper extremity weakness, however, limited the ability to ambulate. Recovery of motor strength in this group is comparable to that of individuals with incomplete tetraplegia in general but the proportion who regain ambulatory function is less.     

Ki-67 and apoptosis in a embryologic model

A 67-year-old man developed slowly progressive muscular weakness in the bilateral upper extremities (C5- 7 regions) without signs of sensory deficit following the cervical radiation therapy (70.5Gy) for right laryngeal cancer 4 years before. These clinical signs resembled those of lower motor neuron disease. MRI with gadolinium-DTPA, however, showed enhancement in the bilateral C5 and C6 anterior roots, suggesting the cervical radiculopathy due to radiotherapy. It is known that radiation to the spinal cord can lead to "selective anterior horn cell injury". This is the first case report of the cervical radiation radiculopathy, which, if without MRI, might be classified into selective anterior horn cell injury. Suggestion is made for the hypothesis that the spinal motoneuron loss in radiation myelopathy would be caused by retrograde degeneration due to anterior root damages.     

Hyperhidrosis as the presenting symptom in post-traumatic syringomyelia

Post-traumatic syringomyelia is now a well known entity and occurs months or years after a spinal cord injury. The presenting symptoms are usually pain, progressive motor weakness, sensory changes, and increased spasticity. Profuse sweating or hyperhidrosis can be a symptom of the post-traumatic syrinx or can occur in autonomic dysreflexia provoked by peripheral stimuli. We present two patients with cervical spine fractures whose presenting symptom of post-traumatic syringomyelia was hyperhidrosis affected by posture. The pathophysiology involved and the management of these patients is discussed.     

Trigeminal denervation and operant behavior in the rat.

39 male Wistar rats underwent selective sectioning of trigeminal sensory and motor nerves in 2 experiments to examine the contribution of the sensorimotor system to the control of instrumental responses reinforced with food or water. It was hypothesized that trigeminal denervation would disrupt motivational systems mediating Ss' thirst and hunger. Results show that unilateral sectioning of either Section V sensory or V motor nerves had no significant effect on leverpressing. Bilateral sectioning significantly reduced leverpressing, and the deficit was greatest in Ss with trigeminal motor nerve sectioning. It is concluded that trigeminal orosensory or oromotor denervation disrupts performance on a food- or water-reinforced task in which execution does not require a trigeminally mediated response. Findings are discussed in terms of motivational and reinforcement accounts of instrumental learning. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endomorphin-2 is an endogenous opioid in primary sensory afferent fibers

Evidence is presented that the recently discovered endogenous mu-selective agonist, endomorphin-2, is localized in primary sensory afferents. Endomorphin-2-like immunoreactivity was found to be colocalized in a subset of substance P- and mu opiate receptor-containing fibers in the superficial laminae of the spinal cord and spinal trigeminal nucleus. Disruption of primary sensory afferents by mechanical (deafferentation by dorsal rhizotomy) or chemical (exposure to the primary afferent neurotoxin, capsaicin) methods virtually abolished endomorphin-2-like immunoreactivity in the dorsal horn. These results indicate that endomorphin-2 is present in primary afferent fibers where it can serve as the endogenous ligand for pre- and postsynaptic mu receptors and as a major modulator of pain perception.     

Myelopathy after intrathecal chemotherapy. A case report with unique magnetic resonance imaging changes

BACKGROUND: Paraplegia caused by intrathecal chemotherapy has no known pathognomonic features and is a diagnosis of exclusion. METHODS: The authors reported the clinical and neuroimaging findings in one patient with this syndrome. RESULTS: The patient had severe paraplegia with urinary retention and impaired pain and touch sensation below T-10 with sparing of proprioception and vibration sense. Magnetic resonance imaging (MRI) scan showed diminished intensity throughout the central cervical spinal cord. Post-gadopentetate dimeglumine enhancement was scattered throughout the cervical spinal cord and in two areas of the dorsal spinal cord. Axial views of the cervical spinal cord showed that this enhancement was limited to the lateral columns. CONCLUSIONS: The MRI in myelopathy due to intrathecal chemotherapy may show a unique pattern of postgadopentetate dimeglumine enhancement limited to the lateral columns of the spinal cord. However, two recently encountered patients with the same syndrome did not show similar changes.     

Allelic loss on chromosome 9 in bladder cancer tissues and urine samples detected by blunt-end single-strand DNA conformation polymorphism

BACKGROUND: A high incidence of backache with radiating pains to the lower extremities, termed transient radicular irritation (TRI), has been reported following the use of 5% hyperbaric lidocaine. This has been attributed to a neurotoxic reaction. METHODS: A retrospective audit has been carried out in our hospital on the postoperative anaesthetic records of all patients from the 1st of January 1993 to the 1st of September 1996, who received spinal anaesthesia with either hyperbaric lidocaine or hyperbaric bupivacaine for day-care surgery. RESULTS: Backache was reported in 1.9% of patients (6/322) receiving hyperbaric lidocaine and in 2.4% of patients (1/41) receiving hyperbaric bupivacaine. This was not associated with any sensory, motor or sphincter disturbances. One patient complained of backache with bilateral pain referred to the gluteal area (TRI), which was assessed as acute facet joint syndrome. Unilateral accidental block of the femoral nerve was observed in 3 patients, sensory disturbances in the L2/3 dermatome was reported in a further 3 patients at 24 h, following wound infiltration with local anaesthetic during hernia repair. CONCLUSIONS: The low incidence of backache at 24 h and the absence of associated symptoms of neurogenic pain, sensory and motor disturbances, does not support the hypothesis that TRI is a neurotoxic reaction, subsequent to the use of hyperbaric lidocaine.     

Severe motor weakness associated with lumbar spinal stenosis. A retrospective study of a series of 61 patients

PURPOSE OF THE STUDY: Severe motor weakness is a rather infrequent symptom in the course of lumbar stenosis. The objectives of this study are three fold: describe the motor deficit, evaluate the prognosis factors and determine the type of stenosis the most likely to be complicated by motor loss. MATERIAL AND METHODS: 61 consecutive patients with a mean age of 63 years, operated on for a lumbar stenosis and with a severe motor deficit have been retrospectively studied. The mean follow-up was 38 months. The overall functional result was evaluated according to a rating scale, specially developed in our unit for the follow-up of lumbar stenosis. The motor capacity was rated from 0 (complete paralysis) to 5 (normal strength). According to that scale the motor weakness was rated as 0, 11 times as 1, 11 times, as 2, 11 times and as 3, 28 times. The deficit was unilateral in 79 per cent of cases and multiradicular in 58 per cent of patients. Sphincter abnormalities were also present in 9 cases. In 9 out of 10 patients the motor deficit was in the L5 territory. Stenosis was extended to 3 levels in 30 cases and was focal in the remaining cases. Degenerative spondylolishthesis was disclosed in 20 patients. In 3 out of 4 cases decompression was performed after 3 weeks of motor weakness and within 3 weeks in the remaining cases. RESULTS: According to our rating scale the overall results were considered excellent in 29 cases, good in 21 cases and fair in the 11 remaining cases. There was no complication, and no postoperative worsening of the deficit was observed. Regression of motor weakness was complete 22 times, partial 29 times and null 10 times. In the eleven complete deficits with a 0 cotation one receded completely, 7 receded partially and no improvement was noted in the 3 remaining cases. 6 out of the 9 patients with sphincter abnormalities recovered completely. In this study favourable prognosis parameters were as follows: age under 62 years, monoradicular deficit, stenosis at one level and association with a discal herniation. In contrast, severity of the initial motor weakness, association with sphincter abnormalities, presence or not of degenerative spondylolisthesis, or of a complete block on the myelogram were not influential variables. Chances of recovery were statistically diminished when decompression was performed after 6 weeks. DISCUSSION AND CONCLUSION: No study dealing specifically with the postoperative outcome of motor deficit caused by lumbar stenosis has been published. However the rate of motor recovery (complete or partial) disclosed in our series is comparable with that found in other series dealing more generally with the overall post-surgery outcome. At our last follow-up, 82 per cent of our patients were considered as having an excellent or good result. It can be concluded that the existence of a motor deficit is not a major pejorative factor of the overall final functional result. Motor weakness is more frequently observed in elderly patients, in cases with degenerative spondylolisthesis, or when a discal herniation is associated with a bony compression. Chances of recovery are better, when the deficit is monoradicular, when the stenosis is focal, or associated with a discal herniation and when the patient is relatively young.