Quadriceps weakness due to disc protrusion causing nerve root compression. A case report and literature review

Most common presentation of spinal disc herniation is pain. Next common presentation is pain associated with neurological symptoms [1] . It is relatively unusual to present muscular weakness purely due to disc herniation in the absence of lower back or neuropathic pain and can be a diagnostic challenge. A male patient of 45 presented to his family physician with five days history of weakness in the left quadriceps. There was no pain in the back or leg or any sensory symptoms at this stage. There was no other significant past medical history apart of history of spontaneous disc prolapse when he was 26. (radiating pain to the left leg but no neurological symptoms at that time). Clinical examination revealed motor deficit of 4/5 in the left quadriceps and diminished knee reflex. There was no sensory deficit elicited at this stage. Patient was referred to neurologist (by this time patient had developed sensory deficit at medial lower leg) who arranged nerve conduction studies which revealed L4 radiculopathy. Patient was referred to spinal surgeon who after consultation arranged MRI of the lumbosacral spine which showed disc extrusion at L3-4 level causing root compression of L4 nerve root. Since the patient was active sportsman, it was decided to do discectomy. However, after case discussion in spinal team meeting, (and patient started to feel slight improvement in sensory symptoms after couple of weeks) it was decided to manage conservatively. Patient started physiotherapy for three months and gradually noticed complete resolution of sensory loss after a month and gradual improvement in motor weakness. Patient started light sporting activities after three months of orthopaedic consultation. Patient continued to recover and had complete resolution of motor symptoms within a year. Patient had a follow up MRI after about a year which showed subtle improvement of compression at the same level. Patient was discharged from outpatient follow up. This case illustrates diagnostic dilemma when symptoms are not typical. However, it is proven the ‘common things are common’ again. Conservative management seems to be way forward when neurological symptoms are mild especially in the absence of neuropathic pain, However, it needs to be decided on case-by-case basis

Eye movements elevate crowding in congenital idiopathic nystagmus

Congenital idiopathic nystagmus (sometimes known as infantile nystagmus) is a disorder characterised by involuntary eye movements, which leads to decreased acuity and visual function. One such function is visual crowding, a process whereby objects that are easily recognised in isolation become impaired by nearby flankers. Crowding typically occurs in the peripheral visual field, though elevations in foveal vision have been reported in congenital nystagmus, similar to those found with amblyopia (another developmental visual disorder). Here we examine whether the elevated foveal crowding with nystagmus is driven by similar mechanisms to those documented in amblyopia – long-term neural changes associated with a sensory deficit – or by the momentary displacement of the stimulus through nystagmus eye movements. We used a Landolt-C orientation identification task to measure threshold gap sizes with and without flanker Landolt-Cs that were either horizontally or vertically placed. Because nystagmus is predominantly horizontal, crowding should be stronger with horizontal flankers if eye movements cause the interference, whereas a sensory deficit should be equivalent for the two dimensions. Consistent with an origin in eye movements, we observe elevations in nystagmic crowding that are above that of typical vision, and stronger with horizontal than vertical flankers. This horizontal elongation was not found in either amblyopic or typical vision. We further demonstrate that the same pattern of performance can be obtained in typical vision with stimulus movement that simulates nystagmus. We consequently propose that the origin of nystagmic crowding lies in the eye movements, either through relocation of the stimulus into peripheral retina or image smear of the target and flanker elements.

Lateral lumbar interbody fusion without intraoperative neuromonitoring: a single-center consecutive series of 157 surgeries

OBJECTIVELateral lumbar interbody fusion (LLIF) is frequently used for anterior column stabilization. Many authors have reported that intraoperative neuromonitoring (IONM) of the lumbar plexus nerves is mandatory for this approach. However, even with IONM, the reported motor and sensory deficits are still considerably high. Thus, the authors’ approach was to focus on the indication, trajectory, and technique instead of relying on IONM findings per se. The objective of this study therefore was to analyze the outcome of our large cohort of patients who underwent LLIF without IONM.METHODSThe authors report on 157 patients included from 2010 to 2016 who underwent LLIF as an additional stabilizing procedure following dorsal instrumentation. LLIF-related complications as well as clinical outcomes were evaluated.RESULTSThe mean follow-up was 15.9 ± 12.0 months. For 90.0% of patients, cage implantation by LLIF was the first retroperitoneal surgery. There were no cases of surgery-related hematoma, vascular injury, CSF leak, or any other visceral injury. Between 1 and 4 cages were implanted per surgery, most commonly at L2–3 and L3–4. The mean length of surgery was 92.7 ± 35 minutes, and blood loss was 63.8 ± 57 ml. At discharge, 3.8% of patients presented with a new onset of motor weakness, a new sensory deficit, or the deterioration of leg pain due to LLIF surgery. Three months after surgery, 3.5% of the followed patients still reported surgery-related motor weakness, 3.6% leg pain, and 9.6% a persistent sensory deficit due to LLIF surgery.CONCLUSIONSThe results of this series demonstrate that the complication rates for LLIF without IONM are comparable, if not superior, to those in previously reported series using IONM. Hence, the authors conclude that IONM is not mandatory for LLIF procedures if the surgical approach is tailored to the respective level and if the visualization of nerves is performed.

The role of sensory stimulation on motor learning via action observation: a mini review

Action observation involves the observation of an action followed by an attempt to replicate it. Recent studies show that increased sensorimotor cortical connectivity improves motor performance via observation and that priming the sensory system before observation enhances the effects of observation-based learning. Understanding the role of the sensory system is, therefore, critical for rehabilitation of movement disorders that have a sensory deficit.

Potentials of Ultrahigh-Field MRI for the Study of Somatosensory Reorganization in Congenital Hemiplegia

Reorganization of somatosensory function influences the clinical recovery of subjects with congenital unilateral brain lesions. Ultrahigh-field (UHF) functional MRI (fMRI) with the use of a 7 T magnet has the potential to contribute fundamentally to the current knowledge of such plasticity mechanisms. The purpose of this study was to obtain preliminary information on the possible advantages of the study of somatosensory reorganization at UHF fMRI. We enrolled 6 young adults (mean age 25 ± 6 years) with congenital unilateral brain lesions (4 in the left hemisphere and 2 in the right hemisphere; 4 with perilesional motor reorganization and 2 with contralesional motor reorganization) and 7 healthy age-matched controls. Nondominant hand sensory assessment included stereognosis and 2-point discrimination. Task-dependent fMRI was performed to elicit a somatosensory activation by using a safe and quantitative device developed ad hoc to deliver a reproducible gentle tactile stimulus to the distal phalanx of thumb and index fingers. Group analysis was performed in the control group. Individual analyses in the native space were performed with data of hemiplegic subjects. The gentle tactile stimulus showed great accuracy in determining somatosensory cortex activation. Single-subject gentle tactile stimulus showed an S1 activation in the postcentral gyrus and an S2 activation in the inferior parietal insular cortex. A correlation emerged between an index of S1 reorganization (distance between expected and reorganized S1) and sensory deficit (p<0.05) in subjects with hemiplegia, with higher distance related to a more severe sensory deficit. Increase in spatial resolution at 7 T allows a better localization of reorganized tactile function validated by its correlation with clinical measures. Our results support the S1 early-determination hypothesis and support the central role of topography of reorganized S1 compared to a less relevant S1-M1 integration.

Effect of severity of hypertension on brain stem auditory evoked potentials

Background: Hypertension is one of the most important public health problems among worldwide. Central nervous system dysfunctions are common in these patients due to micro-infarctions caused by arteriolar spasm of cerebral blood vessels. This will lead to hypoperfusion, subcortical white matter demyelination, and cognitive decline. The Brainstem auditory evoked potentials (BAEP) are far field subcortical electrical potentials which provide an objective electrophysiological method for assessing the auditory pathway from auditory nerve to the brainstem. Aim and objective of the study was to assess the effect of increasing severity of hypertension on the brainstem auditory pathway, among the patients of essential hypertension.Methods: A total of 75 subjects of age group 30 to 60 years were included in the study. Among them 25 were healthy age and sex matched controls (Group I), 25 were stage 1 hypertensives (Group IIa) and 25 were stage 2 hypertensives (Group IIb) as per JNC 7 criteria. The absolute latencies I, III, V and interpeak latencies (IPL) I-III, III-V, I-V were recorded by using Neuroperfect EMG 2000 system with installed BAER and data were statistically analyzed using Student unpaired t test.Results: All the hypertensive (Group IIa and IIb) patients were found to have significantly prolonged absolute latency of wave III, V and IPL III-V, I-V as compared to that of normal healthy controls. The wave V latency was prolonged as the severity of hypertension increased. Intergroup comparison among hypertensive patients (Group IIa and IIb) revealed a significant prolongation of absolute latency of Wave III, V and IPL III-V, I-V.Conclusions: The results show that there exists a sensory deficit along with synaptic delay across the auditory pathway in the hypertensive patients and the sensory deficit progresses with the severity of the disease.

Effects of Temporary Functional Deafferentation in Chronic Stroke Patients: Who Profits More?

Temporary functional deafferentation (TFD) by an anesthetic cream on the stroke-affected forearm was shown to improve sensorimotor abilities of stroke patients. The present study investigated different predictors for sensorimotor improvements during TFD and indicated outcome differences between patients grouped in subcortical lesions only and lesions with any cortical involvement. Thirty-four chronic stroke patients were temporarily deafferented on the more affected forearm by an anesthetic cream. Somatosensory performance was assessed using von Frey Hair and grating orientation task; motor performance was assessed by a shape-sorter-drum task. Seven potential predictors were entered into three linear multiple regression models. Furthermore, effects of TFD on outcome variables for the two groups (cortical versus subcortical lesion) were compared. Sex and sensory deficit were significant predictors for changes in motor function while age accounted for changes in grating orienting task. Males, patients with a stronger sensory deficit, and older patients profited more. None of the potential predictors made significant contributions to changes in threshold for touch. Furthermore, there were no differences in sensorimotor improvement between lesion site groups. The effects of TFD together with the low predictability of the investigated parameters suggest that characteristics of patients alone are not suitable to exclude some patients from TFD.

Cochlear Implants and Children with Vestibular Impairments

Sensorineural hearing loss (SNHL) in children occurs in 1 to 3% of live births and acquired hearing loss can additionally occur. This sensory deficit has far reaching consequences that have been shown to extend beyond speech and language development. Thankfully there are many therapeutic options that exist for these children with the aim of decreasing the morbidity of their hearing impairment. Of late, focus has shifted beyond speech and language outcomes to the overall performance of children with SNHL in real-world environments. To account for their residual deficits in such environments, clinicians must understand the extent of their sensory impairments. SNHL commonly coexists with other sensory deficits such as vestibular loss. Vestibular impairment is exceedingly common in children with SNHL with nearly half of children exhibiting vestibular end-organ dysfunction. These deficits naturally lead to impairments in balance and delay in motor milestones. However, this additional sensory deficit likely leads to further impairment in the performance of these children. This article focuses on the following:1. Defining the coexistence of vestibular impairment in children with SNHL and cochlear implants.2. Describing screening methods aimed at identifying vestibular dysfunction in children with SNHL.3. Understanding the functional implications of this dual-sensory impairment.4. Exploring possible rehabilitative strategies to minimize the impact of vestibular impairment in children with SNHL