Addressing challenges for repairing adult spinal cord with insights from neonates

Stem cell therapy has emerged as a promising area of scientific investigation, sparking considerable interest, especially in spinal cord injury (SCI). Sun et al.1 discover that the extracellular matrix (ECM) from the neonatal spinal cord transmits biochemical signals to endogenous axons, thus promoting axonal regeneration.

Traumatic Brain Injuries After Falls From Height vs Falls at the US-Mexico Border Wall

This cohort study examines the incidence, severity, and mortality of fall-related injuries among migrants at the US-Mexico border in San Diego, California.

Characterizing the frequency, morbidity, and types of traumatic brain injuries after the Mexico-San Diego border wall extension: a retrospective cohort review

OBJECTIVE

The aim of this study was to investigate the impact of the US-Mexico border wall height extension on traumatic brain injuries (TBIs) and related costs.

METHODS

In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from falling at the border wall between 2016 and 2021 were considered. Patients in the pre-height extension period (January 2016-May 2018) were compared with those in the post-height extension period (January 2020-December 2021). Demographic characteristics, clinical data, and hospital charges were analyzed.

RESULTS

A total of 383 patients were identified: 51 (0 TBIs, 68.6% male) in the pre-height extension cohort and 332 (14 TBIs, 77.1% male) in the post-height extension cohort, with mean ages of 33.5 and 31.5 years, respectively. There was an increase in the average number of TBIs per month (0.0 to 0.34) and operative TBIs per month (0.0 to 0.12). TBIs were associated with increased Injury Severity Score (8.8 vs 24.2, p < 0.001), median (IQR) hospital length of stay (5.0 [2-11] vs 8.5 [4-45] days, p = 0.03), and median (IQR) hospital charges ($163,490 [$86,369-$277,918] vs $243,658 [$136,769-$1,127,920], p = 0.04). TBIs were normalized for changing migration rates on the basis of Customs and Border Protection apprehensions.

CONCLUSIONS

This heightened risk of intracranial injury among vulnerable immigrant populations poses ethical and economic concerns to be addressed regarding border wall infrastructure.

Novel association of blunt cerebrovascular injuries with the San Diego-Mexico border wall height extension

BACKGROUND

The San Diego-Mexico border wall height extension is associated with increased traumatic injuries and related costs after wall falls. We report previous trends and a neurological injury type not previously associated with border falls: blunt cerebrovascular injuries (BCVIs).

METHODS

In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from border wall falls from 2016-2021 were considered. Patients were included if they were admitted in the pre-height extension period (January 2016-May 2018) or post-height extension period (June 2018-December 2021). Demographics, clinical data, and hospital stay data were compared.

RESULTS

We identified 383 patients, 51 (68.6% male; mean age 33.5 years) in the pre-height extension cohort and 332 (77.1% male; mean age 31.5 years) in the post-height extension cohort. There were 0 and 5 BCVIs in the pre-height and post-height extension groups respectively. BCVIs were associated with increased injury severity scores (9.16 vs 31.33; p<0.001), median ICU length of stay (0 [IQR 0-3] vs 5 [IQR 2-21]; p=0.022), and total hospital charges ($163,490 [IQR $86,578, $282,036] vs $835,260 [IQR $171,049, $1,933,996]; p=0.048). Poisson modeling found BCVI admissions were 0.21 (95%CI 0.07-0.41; p=0.042) per month higher post-height extension.

CONCLUSIONS

We review the injuries correlated with the border wall extension and reveal an association with rare, potentially devastating BCVIs that were not seen before the border wall modifications. These BCVIs and associated morbidity shed light on the trauma increasingly found at the southern US border, which may be informative for future infrastructure policy decisions.

Case report: Neuronal intranuclear inclusion disease presenting with acute encephalopathy

Neuronal intranuclear inclusion disease (NIID), a neurodegenerative disease previously thought to be rare, is increasingly recognized despite heterogeneous clinical presentations. NIID is pathologically characterized by ubiquitin and p-62 positive intranuclear eosinophilic inclusions that affect multiple organ systems, including the brain, skin, and other tissues. Although the diagnosis of NIID is challenging due to phenotypic heterogeneity, a greater understanding of the clinical and imaging presentations can improve accurate and early diagnosis. Here, we present three cases of pathologically proven adult-onset NIID, all presenting with episodes of acute encephalopathy with protracted workups and lengthy time between symptom onset and diagnosis. Case 1 highlights challenges in the diagnosis of NIID when MRI does not reveal classic abnormalities and provides a striking example of hyperperfusion in the setting of acute encephalopathy, as well as unique pathology with neuronal central chromatolysis, which has not been previously described. Case 2 highlights the progression of MRI findings associated with multiple NIID-related encephalopathic episodes over an extended time period, as well as the utility of skin biopsy for antemortem diagnosis.

Derivation of Sendai-Virus-Reprogrammed Human iPSCs-Neuronal Precursors: In Vitro and In Vivo Post-grafting Safety Characterization

The critical requirements in developing clinical-grade human-induced pluripotent stem cells-derived neural precursors (hiPSCs-NPCs) are defined by expandability, genetic stability, predictable in vivo post-grafting differentiation, and acceptable safety profile. Here, we report on the use of manual-selection protocol for generating expandable and stable human NPCs from induced pluripotent stem cells. The hiPSCs were generated by the reprogramming of peripheral blood mononuclear cells with Sendai-virus (SeV) vector encoding Yamanaka factors. After induction of neural rosettes, morphologically defined NPC colonies were manually harvested, re-plated, and expanded for up to 20 passages. Established NPCs showed normal karyotype, expression of typical NPCs markers at the proliferative stage, and ability to generate functional, calcium oscillating GABAergic or glutamatergic neurons after in vitro differentiation. Grafted NPCs into the striatum or spinal cord of immunodeficient rats showed progressive maturation and expression of early and late human-specific neuronal and glial markers at 2 or 6 months post-grafting. No tumor formation was seen in NPCs-grafted brain or spinal cord samples. These data demonstrate the effective use of in vitro manual-selection protocol to generate safe and expandable NPCs from hiPSCs cells. This protocol has the potential to be used to generate GMP (Good Manufacturing Practice)-grade NPCs from hiPSCs for future clinical use.

Expandable Sendai-Virus-Reprogrammed Human iPSC-Neuronal Precursors: In Vivo Post-Grafting Safety Characterization in Rats and Adult Pig

One of the challenges in clinical translation of cell-replacement therapies is the definition of optimal cell generation and storage/recovery protocols which would permit a rapid preparation of cell-treatment products for patient administration. Besides, the availability of injection devices that are simple to use is critical for potential future dissemination of any spinally targeted cell-replacement therapy into general medical practice. Here, we compared the engraftment properties of established human-induced pluripotent stem cells (hiPSCs)-derived neural precursor cell (NPCs) line once cells were harvested fresh from the cell culture or previously frozen and then grafted into striata or spinal cord of the immunodeficient rat. A newly developed human spinal injection device equipped with a spinal cord pulsation-cancelation magnetic needle was also tested for its safety in an adult immunosuppressed pig. Previously frozen NPCs showed similar post-grafting survival and differentiation profile as was seen for freshly harvested cells. Testing of human injection device showed acceptable safety with no detectable surgical procedure or spinal NPCs injection-related side effects.

The impact of the Mexico-San Diego border wall extension on spine injuries: a retrospective cohort review

BACKGROUND

The recent San Diego-Mexico border wall height extension has resulted in an increased injury risk for unauthorized immigrants falling from greater heights. However, the effects of the border wall extension on frequency and morbidity of spinal injuries and related economic costs have yet to be highlighted.

METHODS

We retrospectively compared two cohorts who presented to the UC San Diego Health Trauma Center for border wall falls: pre-height extension (12 patients; January 2016-May 2018), and post-height extension (102 patients; January 2020-December 2021). Patients presented during border wall construction (June 2018-December 2019) were excluded. Demographics, clinical data and hospital costs were collected. Spinal injuries were normalized using Customs and Border Protection apprehensions. Costs were adjusted for inflation using the 2021 medical care price index.

RESULTS

The increase in spine injuries per month (0.8-4.25) and operative spine injuries per month (0.3- 1.7) was statistically significant (P < 0.001). Increase in median length of stay from 6 [interquartile range (IQR) 2-7] to 9 days (IQR 6-13) was statistically significant (P = 0.006). Median total hospital charges increased from $174 660 to $294 421 and was also significant (P < 0.001).

CONCLUSION

The data support that the recent San Diego-Mexico border wall extension is correlated with more frequent, severe and costly spinal injuries. This current infrastructure should be re-evaluated as border-related injuries represent a humanitarian and public health crisis.

Constructing 2D maps of human spinal cord activity and isolating the functional midline with high-density microelectrode arrays

Intraoperative neuromonitoring (IONM) is a widely used practice in spine surgery for early detection and minimization of neurological injury. IONM is most commonly conducted by indirectly recording motor and somatosensory evoked potentials from either muscles or the scalp, which requires large-amplitude electrical stimulation and provides limited spatiotemporal information. IONM may inform of inadvertent events during neurosurgery after they occur, but it does not guide safe surgical procedures when the anatomy of the diseased spinal cord is distorted. To overcome these limitations and to increase our understanding of human spinal cord neurophysiology, we applied a microelectrode array with hundreds of channels to the exposed spinal cord during surgery and resolved spatiotemporal dynamics with high definition. We used this method to construct two-dimensional maps of responsive channels and define with submillimeter precision the electrophysiological midline of the spinal cord. The high sensitivity of our microelectrode array allowed us to record both epidural and subdural responses at stimulation currents that are well below those used clinically and to resolve postoperative evoked potentials when IONM could not. Together, these advances highlight the potential of our microelectrode arrays to capture previously unexplored spinal cord neural activity and its spatiotemporal dynamics at high resolution, offering better electrophysiological markers that can transform IONM.

Traumatic rupture of thoracic epidural capillary hemangioma resulting in acute neurologic deficit: illustrative case

BACKGROUND

Thoracic epidural capillary hemangioma is exceedingly rare, with only a few reported cases. The typical presentation usually includes chronic, progressive symptoms of spinal cord compression in middle-aged adults. To the authors’ knowledge, this case is the first report in the literature of acute traumatic capillary hemangioma rupture.

OBSERVATIONS

A 22-year-old male presented with worsening lower extremity weakness and paresthesias after a fall onto his spine. Imaging showed no evidence of spinal fracture but revealed an expanding hematoma over 24 hours. Removal of the lesion demonstrated a ruptured capillary hemangioma.

LESSONS

This unique case highlights a rare occurrence of traumatic rupture of a previously unknown asymptomatic thoracic capillary hemangioma in a young adult.

Review of operative considerations in spinal cord stem cell therapy

Spinal cord injury (SCI) can permanently impair motor and sensory function and has a devastating cost to patients and the United States healthcare system. Stem cell transplantation for treatment of SCI is a new technique aimed at creating biological functional recovery. Operative techniques in stem cell transplantation for SCI are varied. We review various clinical treatment paradigms, surgical techniques and technical considerations important in SCI treatment. The NCBI PubMed database was queried for “SCI” and “stem cell” with a filter placed for “clinical trials”. Thirty-nine articles resulted from the search and 29 were included and evaluated by study authors. A total of 10 articles were excluded (9 not SCI focused or transplantation focused, 1 canine model). Key considerations for stem cell transplantation include method of delivery (intravenous, intrathecal, intramedullary, or excision and engraftment), time course of treatment, number of treatments and time from injury until treatment. There are no phase III clinical trials yet, but decreased time from injury to treatment and a greater number of stem cell injections both seem to increase the chance of functional recovery.

Basal impulses: findings from the last twenty years on impulsivity and reward pathways using deep brain stimulation

INTRODUCTION

Deep brain stimulation (DBS) is an important treatment modality for movement disorders. Its role in tasks and processes of higher cortical function continues to increase in importance and relevance. This systematic review investigates the impact of DBS on measures of impulsivity.

EVIDENCE ACQUISITION

A total of 45 studies were collated from PubMed (30 prospective, 8 animal, 4 questionnaire-based, and 3 computational models), excluding case reports and review articles. Two areas extensively studied are the subthalamic nucleus (STN) and nucleus accumbens (NAc).

EVIDENCE SYNTHESIS

While both are part of the basal ganglia, the STN and NAc have extensive connections to the prefrontal cortex, cingulate cortex, and limbic system. Therefore, understanding cause and treatment of impulsivity requires understanding motor pathways, learning, memory, and emotional processing. DBS of the STN and NAc shell can increase objective measures of impulsivity, as measured by reaction times or reward-based learning, independent from patient insight. The ability for DBS to treat impulse control disorders, and also cause and/or worsen impulsivity in Parkinson's disease, may be explained by the affected closely-related neuroanatomical areas with discrete and sometimes opposing functions.

CONCLUSIONS

As newer, more refined DBS technology emerges, large-scale prospective studies specifically aimed at treatment of impulsivity disorders are needed.

Immunosuppressive mechanisms for stem cell transplant survival in spinal cord injury

Spinal cord injury (SCI) has been associated with a dismal prognosis-recovery is not expected, and the most standard interventions have been temporizing measures that do little to mitigate the extent of damage. While advances in surgical and medical techniques have certainly improved this outlook, limitations in functional recovery continue to impede clinically significant improvements. These limitations are dependent on evolving immunological mechanisms that shape the cellular environment at the site of SCI. In this review, we examine these mechanisms, identify relevant cellular components, and discuss emerging treatments in stem cell grafts and adjuvant immunosuppressants that target these pathways. As the field advances, we expect that stem cell grafts and these adjuvant treatments will significantly shift therapeutic approaches to acute SCI with the potential for more promising outcomes.

Spinal subpial delivery of AAV9 enables widespread gene silencing and blocks motoneuron degeneration in ALS

Gene silencing with virally delivered shRNA represents a promising approach for treatment of inherited neurodegenerative disorders. In the present study we develop a subpial technique, which we show in adult animals successfully delivers adeno-associated virus (AAV) throughout the cervical, thoracic and lumbar spinal cord, as well as brain motor centers. One-time injection at cervical and lumbar levels just before disease onset in mice expressing a familial amyotrophic lateral sclerosis (ALS)-causing mutant SOD1 produces long-term suppression of motoneuron disease, including near-complete preservation of spinal α-motoneurons and muscle innervation. Treatment after disease onset potently blocks progression of disease and further α-motoneuron degeneration. A single subpial AAV9 injection in adult pigs or non-human primates using a newly designed device produces homogeneous delivery throughout the cervical spinal cord white and gray matter and brain motor centers. Thus, spinal subpial delivery in adult animals is highly effective for AAV-mediated gene delivery throughout the spinal cord and supraspinal motor centers.

The Current State of Rural Neurosurgical Practice: An International Perspective

Introduction:

Rural and low-resource areas have diminished capacity to care for neurosurgical patients due to lack of infrastructure, healthcare investment, and training programs. This review summarizes the range of rural neurosurgical procedures, novel mechanisms for delivering care, rapid training programs, and outcome differences across international rural neurosurgical practice.

Methods:

A comprehensive literature search was performed for English language manuscripts with keywords “rural” and “neurosurgery” using the National Library of Medicine PubMed database (01/1971–06/2017). Twenty-four articles focusing on rural non-neurosurgical practice were included.

Results:

Time to care and/or surgery and shortage of trained personnel remain the strongest risk factors for mortality and poor outcome. Telemedicine consults to regional centers with neurosurgery housestaff have potential for increased timeliness of diagnosis/triage, improved time to surgery, and reductions in unnecessary transfers in remote areas. Mobile neurosurgery teams have been deployed with success in nations with large transport distances precluding initial transfers. Common neurosurgical procedures involve trauma mechanisms; accordingly, training programs for nonneurosurgery medical personnel on basic assessment and operative techniques have been successful in resource-deficient settings where neurosurgeons are unavailable.

Conclusions:

Protracted transport times, lack of resources/training, and difficulty retaining specialists are barriers to successful outcomes. Advances in telemedicine, mobile neurosurgery, and training programs for urgent operative techniques have been implemented efficaciously. Development of guidelines for paired partnerships between rural centers and academic hospitals, supplying surplus technology to rural areas, and rapid training of qualified local surgical personnel can create sustainable feed-forward programs for trainees and infrastructural solutions to address challenges in rural neurosurgery.

Abstract A078: Dissecting the myeloid lineage in human gliomas

The immune cell composition of the tumor microenvironment can be a decisive factor for tumor pathogenesis. Gliomas are tumors that develop from the glial cells of the brain and spinal cord and make up to 30% of all brain tumors. In gliomas, microglia and infiltrating macrophages can comprise up to 30 to 50% of total tumor-associated cells. Increased CD68 staining, a marker of microglia/macrophages, in adult gliomas is positively associated with histologic tumor grade. Despite the accumulated evidence substantiating a critical role for microglia and infiltrating macrophages in gliomagenesis, little is known is about the molecular mechanisms driving microglial contribution to tumor growth and whether microglia/macrophages are therapeutic targets in both low- and high-grade gliomas. Despite microglia sharing common properties with other tissue-resident macrophages, they express hundreds of genes at higher levels compared to other tissue-resident macrophages, many of which are influenced by the brain micro-environment. Additionally, engraftment of bone-marrow derived cells into the central nervous system fails to produce microglia identical to yolk sac-derived microglia at the transcriptional level. Hence, in any inflammatory context, including cancer, an interesting question arises: how does each population contribute to the pathogenesis and/or resolution of inflammation? To elucidate the role(s) of microglia/macrophages in gliomas, we isolated the myeloid fraction from primary pediatric and adult low-grade and high-grade gliomas using flow cytometry. By integrating bulk and single-cell transcriptome analysis, we find significant inter- and intratumoral heterogeneity within the myeloid population. Additionally, we find evidence for tumor environment-dependent gene change. In combination with ongoing comparative analysis of the corresponding epigenetic landscapes of the myeloid populations, we seek to decipher how the tumor microenvironment reprograms the transcription factor network in microglia/macrophages to generate tumor-promoting cells.

Citation Format: Claudia Z. Han, Sascha H. Duttke, Zhengyu Ouyang, Sebastian Preissl, Johannes C.M. Schlachetzki, Alexander Nott, Conor Fitzpatrick, Carolyn O'Connor, Nicole G. Coufal, Mihir Gupta, David D. Gonda, Michael L. Levy, Ben-Haim Sharona, Barba David, Joseph D. Ciacci, Alexander A. Khalessi, Clark C. Chen, Bing Ren, Christopher K. Glass. Dissecting the myeloid lineage in human gliomas [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A078.

Anterior Versus Transforaminal Lumbar Interbody Fusion: Perioperative Risk Factors and 30-Day Outcomes

Background

Operative management of lower back pain often necessitates anterior lumbar interbody fusion (ALIF) or transforaminal lumbar interbody fusion (TLIF). Specific pathoanatomic advantages and indications exist for both approaches, and few studies to date have characterized comparative early outcomes.

Methods

Adult patients undergoing elective ALIF or TLIF operations were abstracted from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) years 2011-2014. Univariate analyses were performed by surgery cohort for each outcome and adjusted for demographic/clinical variables (age ≥ 65, sex, race, body mass index, American Society of Anesthesiologists physical classification score, functional status, inpatient/outpatient status, smoking, hypertension, Charlson Comorbidity Index) using multivariable regression. Means, standard errors, mean differences (B), odds ratios (ORs), and associated 95% confidence intervals (CIs) are reported. Significance was assessed at P < .05.

Results

Of 8263 subjects (ALIF: 4325, TLIF: 3938), ALIF subjects were younger, less obese, less physically impaired, and had significantly lower rates of hypertension, diabetes, coagulopathy, and previous cardiac surgery. On multivariable analysis, ALIF associated with shorter operative time (B = -11.80 minutes, 95% CI [-16.48, -7.12]; P < .001). Transforaminal lumbar interbody fusion was associated with increased incidence of urinary tract infections (UTIs; OR = 1.57, 95% CI [1.10, 2.26]; P = .013) and of blood transfusions (OR = 1.19, 95% CI [1.04, 1.37]; P = .012). Multivariate analysis also demonstrated TLIF associated with shorter hospital length of stay (B = -0.27 days, 95% CI [-0.54, -0.01]; P = .041), and fewer cases of pneumonia (OR = 0.55, 95% CI [0.32, 0.94]; P = .029) and prolonged ventilator dependency (OR = 0.33, 95% CI [0.12, 0.84]; P = .021).

Conclusions

Comparatively, ALIF patients experienced decreased operative time and decreased incidence of postoperative UTIs and blood transfusions. Anterior lumbar interbody fusion patients were more likely to suffer postoperative pulmonary complications and longer hospital stays. Our data support the notion that both anterior and transforaminal surgical approaches perform comparably in context of 30-day perioperative outcomes.

Risk factors for 30-day outcomes in elective anterior versus posterior cervical fusion: A matched cohort analysis

OBJECTIVE

Cervical spine fusion is the preferred treatment modality for a variety of degenerative and/or myelopathic disorders. Surgeons select between two approaches (anterior or posterior cervical fusion [ACF; PCF]) based on pathoanatomical features and spinal levels involved. Complications and outcome profiles between the approaches following elective surgery have not been systematically investigated.

METHODS

Adult patients undergoing elective ACF or PCF were extracted from the American College of Surgeons National Surgical Quality Improvement Program years 2011-2014. Five hundred twenty-eight patients (264 ACF and 264 PCF) were matched 1:1 by age, sex, functional status, vertebral levels operated, and the American Society of Anesthesiologists classification. Multivariable regression was performed by surgical approach for operation time, complications, hospital length of stay (HLOS), and discharge destination, controlling for body mass index and comorbidities. Mean differences (B), odds ratios (ORs), and 95% confidence intervals (CIs) are reported.

RESULTS

Compared to ACF, PCF was associated with increased odds of blood transfusions >1 unit (OR = 4.31, 95% CI [1.18-15.75]; P = 0.027) and failure to discharge to home (OR = 3.68 [2.17-6.25]; P < 0.001), and increased mean HLOS (B = 1.72 days [1.19-2.26]; P < 0.001). No differences in operation time, other complications, or reoperation rates were found by surgical approach.

CONCLUSIONS

In a matched cohort analysis by age, sex, functional and physical status, and vertebral levels, elective PCF is associated with increased HLOS and increased likelihood of failing to discharge to home compared to ACF without increased risk of 30-day complications. Increased blood transfusion volume is noted for patients undergoing PCF. Future prospective studies are warranted.

Depression After Spinal Surgery: A Comparative Analysis of the California Outcomes Database

OBJECTIVE

To examine the relative incidence of newly recorded diagnosis of depression after spinal surgery as a proxy for the risk of post-spinal surgery depression.

PATIENTS AND METHODS

We used the longitudinal California Office of Statewide Health Planning and Development database (January 1, 2000, through December 31, 2010) to identify patients who underwent spinal surgery during these years. Patients with documented depression before surgery were excluded. Risk of new postoperative depression was determined via the incidence of newly recorded depression on any hospitalization subsequent to surgery. For comparison, this risk was also determined for patients hospitalized during the same time period for coronary artery bypass grafting, hysterectomy, cholecystectomy, chronic obstructive pulmonary disease, congestive heart failure exacerbation, or uncomplicated vaginal delivery.

RESULTS

Our review identified 1,078,639 patients. Relative to the uncomplicated vaginal delivery cohort, the adjusted hazard ratios (HRs) for newly recorded depression within 5 years after the admission of interest were 5.05 for spinal surgery (95% CI, 4.79-5.33), 2.33 for coronary artery bypass grafting (95% CI, 2.15-2.54), 3.04 for hysterectomy (95% CI, 2.88-3.21), 2.51 for cholecystectomy (95% CI, 2.35-2.69), 2.44 for congestive heart failure exacerbation (95% CI, 2.28-2.61), and 3.04 for chronic obstructive pulmonary disease (95% CI, 2.83-3.26). Among patients who underwent spinal surgery, this risk of postoperative depression was highest for patients who underwent fusion surgery (HR, 1.28; 95% CI, 1.22-1.36) or had undergone multiple spinal operations (HR, 1.22; 95% CI, 1.16-1.29) during the analyzed period.

CONCLUSION

Patients who undergo spinal surgery have a higher risk for postoperative depression than patients treated for other surgical or medical conditions known to be associated with depression.

Lateral mass screw stimulation thresholds in posterior cervical instrumentation surgery: a predictor of medial deviation

OBJECTIVE Normative data exists for stimulus-evoked pedicle screw electromyography (EMG) current thresholds in the lumbar spine, and is routinely referenced during spine surgeries to detect a screw breach, prevent injury of neural elements, and ensure the most biomechanically sound instrumentation construct. To date, similar normative data for cervical lateral mass screws is limited, thus the utility of lateral mass screw testing remains unclear. To address this disparity, in this study the authors describe cumulative lateral mass screw stimulation threshold data in patients undergoing posterior cervical instrumentation with lateral mass screws. These data are correlated with screw placement on postoperative imaging, and a novel correlation is discovered with direct clinical implications. METHODS Using a ball-tip probe, 154 lateral mass screws in 21 patients were electrically tested intraoperatively. In each case, for each screw, the lowest (or threshold) current at which the first polyphasic stimulus-evoked EMG response was reproducibly observed by a neurophysiologist was recorded. All patients underwent postoperative CT. Screw position within the lateral mass was first measured in the axial and sagittal planes for each lateral mass screw using the CT images. Screw placement was also evaluated by 2 independent physicians, blinded to current threshold data, on a binary scale of acceptability. The predictive capacity of screw EMG threshold data was evaluated via multivariable regression analyses and receiver operating characteristic (ROC) analyses. Predictive capacity was examined with respect to screw position within the lateral mass, as well as screw acceptability. RESULTS Lateral mass screw EMG thresholds did not appear to differ significantly for screws considered "acceptable" versus "unacceptable" according to the radiographic criteria. Accordingly, ROC analysis confirmed that EMG current threshold data were of minimal utility in predicting screw radiographic acceptability. However, EMG threshold was significantly predictive of screw medial distance from the spinal canal. A screw stimulating below 7.5 mA correctly identified a screw as being within 2 mm of the spinal canal with 75% sensitivity and 92% specificity (positive predictive value 20%, negative predictive value 99.3%), independent of its distance relative to other lateral mass landmarks. EMG current threshold was not significantly predictive of screw deviation in the superior or inferior directions, and was inversely predictive of screw deviations in the lateral direction. CONCLUSIONS In the context of uncertainty regarding the utility of cervical lateral mass EMG current threshold data, this study found that EMG current thresholds correspond significantly, and exclusively, with screw distance from the spinal canal. This association appears independent of other criteria for screw misplacement. As such, the authors recommend that EMG current thresholds be referenced in the case of a suspected medial breach as an effective means to rule out screw placement too medial to the spinal canal.

Elective laminectomy and excision of the thoracic spine neoplasm: an evaluation of early outcomes

BACKGROUND

Laminectomy with excision of spinal neoplasms is commonly performed. The current study examines risk profiles associated with elective laminectomies of benign, malignant primary, and secondary/metastatic neoplasms of the thoracic spine.

METHODS

Adult patients undergoing elective thoracic laminectomy and excision of spinal neoplasm were abstracted from ACS-NSQIP years 2011-2014. Patients were classified into three cohorts: benign primary, malignant primary, secondary/metastatic. Univariate and multivariable analyses compared operation time, early complications, hospital length of stay (HLOS), and discharge destination across cohorts.

RESULTS

One-hundred sixty patients were included, aged 58.0±14.8-years. Mean operation time was 209.23±101.52 minutes and cohorts did not differ significantly on multivariable analysis. Mean HLOS was 6.10±7.14 days and did not differ by cohort. Early complications were observed in 15.6% of patients; secondary/metastatic patients associated with increased odds of >1 unit of blood transfusion, but not overall complications. Failure to be discharged home occurred in 31.8% of patients (benign primary: 30.0%, malignant primary: 66.6%, secondary/metastatic: 10.5%; P<0.001). Malignant primary tumors associated with increased multivariable odds of failure to be discharged home (OR 3.63, 95% CI [1.09, 12.10], P=0.036). Tumor location (extradural, intradural/extramedullary, intramedullary) was not a significant predictor of outcomes. A higher number of concurrent fusions were observed for secondary/metastatic laminectomies (benign primary: 7.3%; malignant primary: 5.5%; secondary/metastatic: 36.8%; P<0.001).

CONCLUSIONS

Comparable performance on operation time and HLOS between neoplasm cohorts suggests broad indication of resectional laminectomies for elective treatment. Primary malignant thoracic spine tumors may require higher levels of early postdischarge care. Future studies are needed to confirm these findings.

A Review of Stem Cell Therapy for Spinal Cord Injury: Large Animal Models and the Frontier in Humans

OBJECTIVE

To review the literature of spinal cord injury and stem cell therapy for large animal models and incorporate those results into an understanding of stem cell therapy for human cord injury.

METHODS

Review of the literature.

RESULTS

Eleven canine studies were identified and 3 sub-human primate studies were identified showing variable results.

CONCLUSIONS

Stem cell therapy is a promising therapeutic option for patients with spinal cord injury; however, the technology has many un-answered questions and further research is needed.

Pituitary tumor apoplexy in adolescents

OBJECTIVE

The aim of this study was to determine whether there are differences in pituitary apoplexy and subclinical apoplexy secondary to adenoma hemorrhage in the adolescent population with regard to symptomatology, neuroimaging features, pathology, and outcomes compared with adults.

METHODS

A retrospective series of 9 consecutive patients with a diagnosis of pituitary hemorrhage who were surgically treated at Rady's Children's Hospital San Diego, between 2008 and 2013 were evaluated for clinical, endocrine, neuroradiographic, and pathologic features in association with clinical outcomes.

RESULTS

Nine patients (6 girls, age 14-21 years) presented to our institution with headache (9/9), nausea (3/9), dizziness (4/9), and visual disturbances (6/9) in the setting of a sellar hemorrhagic tumor on magnetic resonance imaging (MRI). Three patients presented with apoplexy and 6 with subclinical apoplexy. Duration of symptoms ranged from 3 days to 1 year. MRI revealed hemorrhage (9/9), rim enhancement (6/9), sphenoid sinus mucosal thickening (2/9), mass effect on the optic chiasm (8/9), and sellar remodeling (9/9). The percentage of hemorrhage preoperatively observed on MRI ranged from 50% to greater than 95%. On presentation, hyperprolactinemia was recorded in 7 patients, 6 of whom had galactorrhea and/or amenorrhea. Open transsphenoidal decompression was performed in 8/9 patients; 7 of 9 were diagnosed with prolactinoma. Biopsy specimens revealed 10%-90% hemorrhage and no infarction in any of the cases. All patients treated showed improvement of symptoms after surgery (average follow-up, 28.2 months). Postoperative complications included transient diabetes insipidus (n = 5), persistent cerebrospinal fluid rhinorrhea (n = 3), and meningitis (n = 1). Five patients had long-term endocrine sequelae of hyperprolactinemia requiring ongoing medical treatment.

CONCLUSIONS

Pituitary hemorrhage resulting in apoplexy or subclinical apoplexy in adolescents may represent a distinct entity with a more indolent symptomatology and more favorable neurologic and endocrine outcome compared with adults that is worthy of further validation in a multi-institutional cohort.

Endometriosis of the conus medullaris causing cyclic radiculopathy

Intramedullary spinal cord hematomas are a rare neurosurgical pathological entity typically arising from vascular and neoplastic lesions. Endometriosis is an extremely rare cause of intramedullary spinal cord hematoma, with only 5 previously reported cases in the literature. Endometriosis is characterized by ectopic endometrial tissue, typically located in the female pelvic cavity, that causes a cyclical pain syndrome, bleeding, and infertility. In the rare case of intramedullary endometriosis of the spinal cord, symptoms include cyclical lower-extremity radiculopathies and voiding difficulties, and can acutely cause cauda equina syndrome. The authors report a case of endometriosis of the conus medullaris, the first to include radiological, intraoperative, and histopathological imaging. A brief review of the literature is also presented, with discussion including etiological theories surrounding intramedullary endometriosis.

Direct pressure on a pseudomeningocele resulting in intraoperative cerebral ischemia

PURPOSE

When positioning patients with meningocele and meningomyelocele, it is standard practice to avoid direct pressure on the lesions. That caution is intended to prevent injury to neural elements within the lesion and violation of the cerebrospinal fluid space. We herein report an additional hazard of direct intraoperative pressure on such lesions. An adult patient with a lumbosacral pseudomeningocele sustained a cerebral ischemic injury as a consequence of direct pressure on the lesion during general anesthesia.

CLINICAL FEATURES

A 32-yr-old male with spina bifida and a pseudomeningocele related to recent lumbar surgery underwent a urologic procedure in the lithotomy position. Because the lesion was recognized to lie to the left of the midline, cushioning was placed under the patient's left hip and buttock. The patient was slow to awaken and has sustained significant long-term cognitive deficits. Imaging is consistent with a diffuse cerebral ischemic insult.

CONCLUSION

In retrospect, the size and leftward extent of the pseudomeningocele were not appreciated preoperatively, and in spite of the care taken, intraoperative pressure was placed on the lesion. This report cautions that intraoperative pressure related to positioning patients with extra-axial lesions containing cerebrospinal fluid (CSF), e.g., meningoceles and pseudomeningoceles, can result in increases in CSF pressure and thereby a reduction in cerebral perfusion pressure sufficient to result in cerebral ischemia.

Amelioration of motor/sensory dysfunction and spasticity in a rat model of acute lumbar spinal cord injury by human neural stem cell transplantation

Introduction

Intraspinal grafting of human neural stem cells represents a promising approach to promote recovery of function after spinal trauma. Such a treatment may serve to: I) provide trophic support to improve survival of host neurons; II) improve the structural integrity of the spinal parenchyma by reducing syringomyelia and scarring in trauma-injured regions; and III) provide neuronal populations to potentially form relays with host axons, segmental interneurons, and/or α-motoneurons. Here we characterized the effect of intraspinal grafting of clinical grade human fetal spinal cord-derived neural stem cells (HSSC) on the recovery of neurological function in a rat model of acute lumbar (L3) compression injury.

Methods

Three-month-old female Sprague–Dawley rats received L3 spinal compression injury. Three days post-injury, animals were randomized and received intraspinal injections of either HSSC, media-only, or no injections. All animals were immunosuppressed with tacrolimus, mycophenolate mofetil, and methylprednisolone acetate from the day of cell grafting and survived for eight weeks. Motor and sensory dysfunction were periodically assessed using open field locomotion scoring, thermal/tactile pain/escape thresholds and myogenic motor evoked potentials. The presence of spasticity was measured by gastrocnemius muscle resistance and electromyography response during computer-controlled ankle rotation. At the end-point, gait (CatWalk), ladder climbing, and single frame analyses were also assessed. Syrinx size, spinal cord dimensions, and extent of scarring were measured by magnetic resonance imaging. Differentiation and integration of grafted cells in the host tissue were validated with immunofluorescence staining using human-specific antibodies.

Results

Intraspinal grafting of HSSC led to a progressive and significant improvement in lower extremity paw placement, amelioration of spasticity, and normalization in thermal and tactile pain/escape thresholds at eight weeks post-grafting. No significant differences were detected in other CatWalk parameters, motor evoked potentials, open field locomotor (Basso, Beattie, and Bresnahan locomotion score (BBB)) score or ladder climbing test. Magnetic resonance imaging volume reconstruction and immunofluorescence analysis of grafted cell survival showed near complete injury-cavity-filling by grafted cells and development of putative GABA-ergic synapses between grafted and host neurons.

Conclusions

Peri-acute intraspinal grafting of HSSC can represent an effective therapy which ameliorates motor and sensory deficits after traumatic spinal cord injury.

Chronic spinal compression model in minipigs: a systematic behavioral, qualitative, and quantitative neuropathological study

The goal of the present study was to develop a porcine spinal cord injury (SCI) model, and to describe the neurological outcome and characterize the corresponding quantitative and qualitative histological changes at 4-9 months after injury. Adult Gottingen-Minnesota minipigs were anesthetized and placed in a spine immobilization frame. The exposed T12 spinal segment was compressed in a dorso-ventral direction using a 5-mm-diameter circular bar with a progressively increasing peak force (1.5, 2.0, or 2.5 kg) at a velocity of 3 cm/sec. During recovery, motor and sensory function were periodically monitored. After survival, the animals were perfusion fixed and the extent of local SCI was analyzed by (1) post-mortem MRI analysis of dissected spinal cords, (2) qualitative and quantitative analysis of axonal survival at the epicenter of injury, and (3) defining the presence of local inflammatory changes, astrocytosis, and schwannosis. Following 2.5-kg spinal cord compression the animals demonstrated a near complete loss of motor and sensory function with no recovery over the next 4-9 months. Those that underwent spinal cord compression with 2 kg force developed an incomplete injury with progressive partial neurological recovery characterized by a restricted ability to stand and walk. Animals injured with a spinal compression force of 1.5 kg showed near normal ambulation 10 days after injury. In fully paralyzed animals (2.5 kg), MRI analysis demonstrated a loss of spinal white matter integrity and extensive septal cavitations. A significant correlation between the magnitude of loss of small and medium-sized myelinated axons in the ventral funiculus and neurological deficits was identified. These data, demonstrating stable neurological deficits in severely injured animals, similarities of spinal pathology to humans, and relatively good post-injury tolerance of this strain of minipigs to spinal trauma, suggest that this model can successfully be used to study therapeutic interventions targeting both acute and chronic stages of SCI.

Expandable titanium cages for thoracolumbar vertebral body replacement: initial clinical experience and review of the literature

Reconstruction of the anterior and middle column after vertebrectomy is essential for restoring stability. Use of expandable implants is supported by an emerging body of literature. Newer expandable cages have some advantages over traditional mesh implants, structural allograft, and polyetheretherketone or carbon fiber cages. To determine the utility of an expandable titanium cage in spine reconstruction, we conducted a retrospective cohort study of patients who had undergone this reconstruction after single or multilevel thoracic and/or lumbar vertebrectomy. Here we report on our experience using expandable cages at 2 large academic medical centers. Outcome was based on both clinical and radiographic measures with cross-sectional analysis. Thirty-five patients were identified. Of these, 20 had undergone surgery for neoplasm, 8 for trauma, and 7 for infection. Mean follow-up was 31 months (range, 12 to 50 months). Early postoperative kyphosis correction, restoration of sagittal alignment at 12 months, and reduction in visual analog scale pain score were significant. There was no difference in Oswestry Disability Index or height restoration. Expandable intervertebral body strut grafts appear to be a safe and effective option in spine reconstruction after a vertebrectomy and should be considered a treatment option.

Lymphoma of the central nervous system in AIDS

Central nervous system (CNS) lymphoma is a common complication of patients with HIV infection occurring in as many as 20% of patients with AIDS. This article reviews current observations on primary CNS lymphoma and systemic AIDS-related lymphoma with CNS involvement. Clinical features, diagnosis, differential diagnosis, clinical course, and therapeutic options are herein reviewed.

Brainstem tethering in Dandy-Walker syndrome: a complication of cystoperitoneal shunting. Case report

Treatment of the Dandy-Walker syndrome has included placement of a ventriculoperitoneal shunt alone or in combination with a posterior fossa cystoperitoneal shunt. Complications in shunting are common and are usually related to malfunction or infection. The authors present a case in which the patient developed headaches and focal cranial nerve deficits following infection caused by a cystoperitoneal shunt. Magnetic resonance imaging showed tethering of the brainstem. A posterior fossa craniotomy with microsurgical untethering and cyst fenestration achieved two goals: improvement of the focal cranial nerve deficits and elimination of the cystoperitoneal shunt.

Clinical trial of Serratia marcescens extract and radiation therapy in patients with malignant astrocytoma

PURPOSE

A clinical trial was undertaken to determine the safety and efficacy of combining a biologic response modifier derived from the bacterium Serratia marcescens (ImuVert) and radiation therapy (RT) in patients with newly diagnosed anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM).

PATIENTS AND METHODS

Fifteen patients who had undergone either a gross total resection, a partial resection, or a biopsy were treated concurrently with ImuVert and RT. Safety and tolerance were examined by assessment of symptomatic reactions recorded at each ImuVert treatment. Efficacy of treatment was examined in terms of time to progression of tumor and survival.

RESULTS

All patients experienced local reactions at the injection sites that consisted of erythema and induration. The majority of patients experienced flu-like symptoms. Hypotension was responsible for the most significant morbidity (which required fluid resuscitation and extended observation) and dose deescalation. No patients were removed from the study because of toxicity. There were no on-study deaths related to ImuVert treatment. Median time to progression was 33.4 weeks, and median survival was 78 weeks.

CONCLUSION

These results compare favorably with those of recent studies in patients with malignant astrocytomas who received multimodality therapy.