H. Francis Farhadi

Infiltrative intramuscular myxoma of the cervical spine: a case report

BACKGROUND CONTEXT Myxomas are benign tumors of mesenchymal cell origin that usually present as solitary lesions. They are infrequently associated with fibrous dysplasia, as in McCune-Albright or Mazabraud syndrome. Myxomas can develop in a variety of locations, although the most frequent sites are the thigh, buttocks, shoulder, and upper arm. Intramuscular myxomas (IMs) refer to lesions that occur within muscle compartments. They have been infrequently reported in the neck musculature. PURPOSE To date, only five cases have been reported within the posterior neck muscles without associated intraspinal extension. To our knowledge, this is the first case of an IM presenting with extension into the spinal canal. STUDY DESIGN We report a case of posterior cervical IM with intraspinal extension presenting in a 63-year-old woman as a palpable mass. METHODS Complete intralesional resection of the tumor was achieved by standard midline posterior approach. Meticulous resection of the entire capsule was achieved and all margins were confirmed to be free of neoplasm. RESULTS A diagnosis of myxoma was provided on pathologic evaluation. Follow-up at 1.5 years confirmed maintained complete resolution of the preoperative symptoms, with no evidence of local recurrence on imaging. CONCLUSIONS Intramuscular myxomas should be included in the differential diagnosis of cervical paraspinal tumors. Furthermore, we suggest that masses involving the axial muscles should be closely monitored and the patient counseled regarding potential neurologic sequelae.

Diffusion tensor imaging in the spotlight on concussion.

Mild traumatic brain injury (mTBI), including concussion, associated with contact sports and activities of daily living is increasingly recognized as a cause for disruption of cognitive functioning involving attention, executive functions, and memory. Emerging evidence indicates that traumatic axonal injury may be associated with long-term cognitive and neuropsychological disability in severe brain injury, as well as the common transient signs and symptoms linked to mTBI. Because traditional neuroimaging sequences are insensitive to the subtle white matter changes that may underlie axonopathy in mTBI, magnetic resonance (MR) diffusion tensor imaging (DTI) has been used for detection of fiber tract disruption and tracking white

Implantation of Neuronal Stem Cells Enhances Object Recognition without Increasing Neurogenesis after Lateral Fluid Percussion Injury in Mice

Cognitive deficits after traumatic brain injury (TBI) are debilitating and contribute to the morbidity and loss of productivity of over 10 million people worldwide. Cell transplantation has been linked to enhanced cognitive function after experimental traumatic brain injury, yet the mechanism of recovery is poorly understood. Since the hippocampus is a critical structure for learning and memory, supports adult neurogenesis, and is particularly vulnerable after TBI, we hypothesized that stem cell transplantation after TBI enhances cognitive recovery by modulation of endogenous hippocampal neurogenesis. We performed lateral fluid percussion injury (LFPI) in adult mice and transplanted embryonic stem cell-derived neural progenitor cells (NPC). Our data confirm an injury-induced cognitive deficit in novel object recognition, a hippocampal-dependent learning task, which is reversed one week after NPC transplantation. While LFPI alone promotes hippocampal neurogenesis, as revealed by doublecortin immunolabeling of immature neurons, subsequent NPC transplantation prevents increased neurogenesis and is not associated with morphological maturation of endogenous injury-induced immature neurons. Thus, NPC transplantation enhances cognitive recovery early after LFPI without a concomitant increase in neuron numbers or maturation.

Impact of Admission Imaging Findings on Neurological Outcomes in Acute Cervical Traumatic Spinal Cord Injury

Variable and unpredictable spontaneous recovery can occur after acute cervical traumatic spinal cord injury (tSCI). Despite the critical clinical and interventional trial planning implications of this tSCI feature, baseline measures to predict neurologic recovery accurately are not well defined. In this study, we used data derived from 99 consecutive patients (78 male, 21 female) with acute cervical tSCIs to assess the sensitivity and specificity of various clinical and radiological factors in predicting recovery at one year after injury. Categorical magnetic resonance imaging parameters included maximum canal compromise (MCC), maximum spinal cord compression (MSCC), longitudinal length of intramedullary lesion (IML), Brain and Spinal Injury Center (BASIC) score, and a novel derived Combined Axial and Sagittal Score (CASS). Logistic regression analysis of the area under the receiver operating characteristic curve (AUC) was applied to assess the differential predictive value of individual imaging markers. Admission American Spinal Injury Association Impairment Scale (AIS) grade, presence of a spinal fracture, and central cord syndrome were predictive of AIS conversion at one year. Both BASIC and IML were stronger predictors of AIS conversion compared with MCC and MSCC (p = 0.0002 and p = 0.04). The BASIC score demonstrated the highest overall predictive value for AIS conversion at one year (AUC 0.94). We conclude that admission intrinsic cord signal findings are robust predictive surrogate markers of neurologic recovery after cervical tSCI. Direct comparison of imaging parameters in this cohort of patients indicates that the BASIC score is the single best acute predictor of the likelihood of AIS conversion.

Clinical and Radiologic Outcomes After Fenestration and Partial Wall Excision of Idiopathic Intradural Spinal Arachnoid Cysts Presenting with Myelopathy

BACKGROUND Intradural spinal arachnoid cysts (ISACs) with associated neurologic deficits are encountered infrequently. Various management strategies have been proposed with minimal data on comparative outcomes. OBJECTIVE We describe the clinical and radiologic presentation as well as the outcomes of 14 surgically managed patients who presented with an ISAC and associated myelopathy. METHODS We retrospectively reviewed the clinical course of consecutive patients presenting with neurologic deficits associated with idiopathic ISACs at our institution. The diagnoses were based on preoperative magnetic resonance imaging studies followed by intraoperative and histopathological confirmation. RESULTS A total of 14 consecutive patients with ISACs (1 cervicothoracic, 12 thoracic, and 1 thoracolumbar) and associated myelopathy were identified. Syringomyelia was noted in 8 patients. All ISACs were treated with cyst fenestration and partial wall resection through a posterior approach. Preoperative neurologic symptoms were noted to be stable or improved in all patients starting at 6-week postoperative follow-up. The median (interquartile range) preoperative mJOA score was 13 (12.0-14.8), whereas the postoperative median score at a mean follow-up of 22 months (range 6-50 months) was 16 (14.0-17.0), which represents a median improvement (ΔmJOA) of 2.0 (1.3-3.0) (P < 0.001). Comparison of ΔmJOA scores between cases without and with associated syrinxes did not reveal a significant difference (P = 0.23). Postoperative magnetic resonance imaging scans revealed spinal cord re-expansion at the level of the ISAC in all cases and either complete or partial syrinx resolution in 7 of 8 cases. CONCLUSIONS Early treatment with fenestration and partial wall resection allows for cord decompression, syrinx resolution, and gradual resolution of myelopathic symptoms in most cases.

Sulfonylureas—a novel treatment to reduce tissue damage after acute spinal cord injury?

The December issue of The Lancet Neurology features a Review article by Ramer and colleagues,1 which gives an excellent overview of best practices and promising new research directions for treatment of spinal cord injury (SCI). We would like to add the following new angle on this crucial matter: the sulfonylurea receptor 1–transient receptor potential melastatin 4 (SUR1–TRPM4) channel is upregulated within hours of SCI at the site of the lesion.2 After CNS injury, the SUR1–TRPM4 channel has been detected in neurons, astrocytes, oligodendrocytes, and microvascular endothelium at the site of injury. Increased expression of this cation channel has been linked to development of vasogenic and cytotoxic oedema, and to subsequent hemorrhagic conversion.2,3 Glibenclamide is an antidiabetic agent from the class of sulfonylureas that acts as an inhibitor of SUR1. Accumulating evidence indicates that glibenclamide might exert beneficial effects in various CNS pathologies.2 Some of these effects of glibenclamide might relate to protection of microvascular endothelium, reduced oedema formation, secondary hemorrhage, and anti-apoptotic and anti-inflammatory mechanisms.2 Importantly, penetration of glibenclamide into the CNS is enabled after focal injury.2 Ramer and colleagues reference a promising recent phase I trial4 of riluzole in acute SCI. It is worth mentioning that, among other effects, riluzole blocks TRPM4. Furthermore, results of a study of severe spinal cord injury in rats showed superiority of glibenclamide over the glutamatergic neurotransmission blocker riluzole regarding complex motor functions, tissue sparing at 6 weeks, and toxicity.5 Clearly, the SUR1–TRPM4 channel deserves further investigation as a drug target in SCI.

Letter to the Editor: What Has Been Learned from Magnetic Resonance Imaging Examination of the Injured Human Spinal Cord: A Canadian Perspective

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Prospective assessment of the safety and early outcomes of sublaminar band placement for the prevention of proximal junctional kyphosis

OBJECTIVE Proximal junctional kyphosis (PJK) can progress to proximal junctional failure (PJF), a widely recognized early and serious complication of multisegment spinal instrumentation for the treatment of adult spinal deformity (ASD). Sublaminar band placement has been suggested as a possible technique to prevent PJK and PJF but carries the theoretical possibility of a paradoxical increase in these complications as a result of the required muscle dissection and posterior ligamentous disruption. In this study, the authors prospectively assess the safety as well as the early clinical and radiological outcomes of sublaminar band insertion at the upper instrumented vertebra (UIV) plus 1 level (UIV+1). METHODS Between August 2015 and February 2017, 40 consecutive patients underwent either upper (T2-4) or lower (T8-10) thoracic sublaminar band placement at the UIV+1 during long-segment thoracolumbar arthrodesis surgery. Outcome measures were prospectively collected and uploaded to a web-based REDCap database specifically designed to include demographic, clinical, and radiological data. All patients underwent clinical assessment, as well as radiological assessment with anteroposterior and lateral 36-inch whole-spine standing radiographs both pre- and postoperatively. RESULTS Forty patients (24 women and 16 men) were included in this study. Median age at surgery was 64.0 years with an IQR of 57.7-70.0 years. Median follow-up was 12 months (IQR 6-15 months). Three procedure-related complications were noted, including 2 intraoperative cerebrospinal spinal fluid leaks and 1 transient neurological deficit. Median visual analog scale (VAS) scores for back pain significantly improved after surgery (preoperatively: 8.0, IQR 6.0-10.0; 1-year follow-up: 2.0, IQR 0.0-6.0; p = 0.001). Median Oswestry Disability Index (version 2.1a) scores also significantly improved after surgery (preoperatively: 56.0, IQR 45.0-64.0; 1-year follow-up: 46.0, IQR 22.2-54.0; p < 0.001). Sagittal vertical axis (preoperatively: 9.0 cm, IQR 5.3-11.6 cm; final follow-up: 4.7 cm, IQR 2.0-6.6 cm; p < 0.001), pelvic incidence-lumbar lordosis mismatch (24.7°, IQR 11.2°-31.2°; 7.7°, IQR -1.2° to 19.5°; p < 0.001), and pelvic tilt (28.7°, IQR 20.4°-32.6°; 17.1°, IQR 10.8°-25.2°; p < 0.001) were all improved at the final follow-up. While proximal junctional (PJ) Cobb angles increased overall at the final follow-up (preoperatively: 4.2°, IQR 1.9°-7.4°; final follow-up: 8.0°, IQR 5.8°-10.3°; p = 0.002), the significant increase was primarily noted starting at the immediate postoperative time point (7.2°, IQR 4.4°-11.8°; p = 0.001) and not beyond. Three patients (7.5%) developed radiological PJK (mean ΔPJ Cobb 15.5°), while there were no instances of PJF in this cohort. CONCLUSIONS Sublaminar band placement at the UIV+1 during long-segment thoracolumbar instrumented arthrodesis is relatively safe and is not associated with an increased rate of PJK. Moreover, no subjects developed PJF. Prospective large-scale and long-term analysis is needed to define the potential benefit of sublaminar bands in reducing the incidence of PJK and PJF following surgery for ASD. Clinical trial registration no.: NCT02411799 (clinicaltrials.gov).

Surgical management of adult type 1 split cord malformation. Report of two cases with literature review

Split cord malformation (SCM) is a rare form of spinal dysraphism wherein the spinal cord is divided longitudinally into two distinct hemicords. Surgery is usually performed in children while management in adults, who rarely manifest symptoms, remains controversial. Both expectant management and prophylactic surgery have been variously advocated. The present article describes our experience in two adult patients with predominant pain-related complaints who underwent surgical excision of type 1 SCM lesions. A comprehensive review of the literature on SCM in adults is also provided. While pain, disability, and quality of life scores improved in these two patients, further larger studies will be required to define the role of surgery in adults with type 1 SCM and a pain-dominant presentation.

Role of proNGF/p75 signaling in bladder dysfunction after spinal cord injury

Loss of bladder control is a challenging outcome facing patients with spinal cord injury (SCI). We report that systemic blocking of pro–nerve growth factor (proNGF) signaling through p75 with a CNS-penetrating small-molecule p75 inhibitor resulted in significant improvement in bladder function after SCI in rodents. The usual hyperreflexia was attenuated with normal bladder pressure, and automatic micturition was acquired weeks earlier than in the controls. The improvement was associated with increased excitatory input to the spinal cord, in particular onto the tyrosine hydroxylase–positive fibers in the dorsal commissure. The drug also had an effect on the bladder itself, as the urothelial hyperplasia and detrusor hypertrophy that accompany SCI were largely prevented. Urothelial cell loss that precedes hyperplasia was dependent on p75 in response to urinary proNGF that is detected after SCI in rodents and humans. Surprisingly, death of urothelial cells and the ensuing hyperplastic response were beneficial to functional recovery. Deleting p75 from the urothelium prevented urothelial death, but resulted in reduction in overall voiding efficiency after SCI. These results unveil a dual role of proNGF/p75 signaling in bladder function under pathological conditions with a CNS effect overriding the peripheral one.