The inactive X chromosome drives sex differences in microglial inflammatory activity in human glioblastoma.

Biological sex is an important risk factor in cancer, but the underlying cell types and mechanisms remain obscure. Since tumor development is regulated by the immune system, we hypothesize that sex-biased immune interactions underpin sex differences in cancer. The male-biased glioblastoma multiforme (GBM) is an aggressive and treatment-refractory tumor in urgent need of more innovative approaches, such as considering sex differences, to improve outcomes. GBM arises in the specialized brain immune environment dominated by microglia, so we explored sex differences in this immune cell type. We isolated adult human TAM-MGs (tumor-associated macrophages enriched for microglia) and control microglia and found sex-biased inflammatory signatures in GBM and lower-grade tumors associated with pro-tumorigenic activity in males and anti-tumorigenic activity in females. We demonstrated that genes expressed or modulated by the inactive X chromosome facilitate this bias. Together, our results implicate TAM-MGs, specifically their sex chromosomes, as drivers of male bias in GBM.

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.

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.

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.

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.

Intradermal and Intramuscular Bupivacaine Reduces Opioid Use Following Noninstrumented Spine Surgery.

OBJECTIVE: To evaluate the efficacy of intraoperative bupivacaine hydrochloride wound infiltration as an adjunct means of pain relief following noninstrumented posterior spine surgery. METHODS: A retrospective cohort analysis was performed of all patients who underwent posterior spinal decompression surgery at the University of California, San Diego, and at the San Diego VA Medical Center between June 2020 and July 2021, following a change in practice to including bupivacaine infiltration at the end of the surgery. Patients were stratified into groups based on whether they received intrawound bupivacaine during surgery. Demographic and clinical data were extracted from the electronic health record. Postoperative opioid use, visual analog pain scores, heart rate, and blood pressure were compared. RESULTS: The analysis included 43 patients; 21 received bupivacaine infiltration, and 22 did not. No complications were encountered in the perioperative period. Patients who received bupivacaine consumed significantly less opioids over the 72 hours following surgery, had slightly lower pain scores, and experienced slightly lower heart rates. No significant difference was found between groups with respect to systolic blood pressure, operative time, or length of hospital stay. CONCLUSIONS: Intraoperative infiltration of the exposed paraspinous musculature and peri-incisional subdermal layer with bupivacaine significantly reduced postoperative opioid consumption for 72 hours after surgery and slightly reduced pain ratings and conferred superior heart rate control. This low-cost intervention produced significant patient benefit with minimal risk and no significant increase in surgical time or hospital stay.

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.

Precision spinal gene delivery-induced functional switch in nociceptive neurons reverses neuropathic pain.

Second-order spinal cord excitatory neurons play a key role in spinal processing and transmission of pain signals to the brain. Exogenously induced change in developmentally imprinted excitatory neurotransmitter phenotypes of these neurons to inhibitory has not yet been achieved. Here, we use a subpial dorsal horn-targeted delivery of AAV (adeno-associated virus) vector(s) encoding GABA (gamma-aminobutyric acid) synthesizing-releasing inhibitory machinery in mice with neuropathic pain. Treated animals showed a progressive and complete reversal of neuropathic pain (tactile and brush-evoked pain behavior) that persisted for a minimum of 2.5 months post-treatment. The mechanism of this treatment effect results from the switch of excitatory to preferential inhibitory neurotransmitter phenotype in dorsal horn nociceptive neurons and a resulting increase in inhibitory activity in regional spinal circuitry after peripheral nociceptive stimulation. No detectable side effects (e.g., sedation, motor weakness, loss of normal sensation) were seen between 2 and 13 months post-treatment in naive adult mice, pigs, and non-human primates. The use of this treatment approach may represent a potent and safe treatment modality in patients suffering from spinal cord or peripheral nerve injury-induced neuropathic pain.

Application of Antibiotic-Impregnated Polymethyl-Methacrylate Bone Cement for the Treatment of Infected Cranioplasties: Initial Experience.

BACKGROUND: Management of infected cranioplasty implants remains a surgical challenge. Surgical debridement, removal of the infected implant, and prolonged antibiotic therapy are part of the acute management. In addition, cranioplasty removal poses the risk of dural tear. Reconstruction of the cranial defect is usually delayed for several months to years, increasing the difficulty due to soft tissue contraction and scarring. OBJECTIVE: The aim of the study was to propose an alternative to delayed reconstruction in the face of infection with a dual purpose: treat the infection with a material which delivers antibiotic to the area (polymethyl-methacrylate antibiotic) and which functions as a temporary or permanent cranioplasty. METHODS: We reviewed the records of 3 consecutive patients who underwent single-stage polymethyl-methacrylate antibiotic salvage cranioplasty. RESULTS: All patients underwent debridement of infected tissue. Titanium mesh was placed over the bony defect. Polymethyl methacrylate impregnated with vancomycin and tobramycin was then spread over the plate and defect before closure. Patients also received extended treatment with systemic antimicrobials. Early outcomes have been encouraging for both cosmesis and treatment of infection. CONCLUSIONS: Benefits of this treatment strategy include immediate reconstruction rather than staged procedures and delivery of high concentrations of antibiotics directly to the affected area in addition to systemic antibiotics.

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.

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.

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.

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.

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.

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.

A First-in-Human, Phase I Study of Neural Stem Cell Transplantation for Chronic Spinal Cord Injury.

We tested the feasibility and safety of human-spinal-cord-derived neural stem cell (NSI-566) transplantation for the treatment of chronic spinal cord injury (SCI). In this clinical trial, four subjects with T2-T12 SCI received treatment consisting of removal of spinal instrumentation, laminectomy, and durotomy, followed by six midline bilateral stereotactic injections of NSI-566 cells. All subjects tolerated the procedure well and there have been no serious adverse events to date (18-27 months post-grafting). In two subjects, one to two levels of neurological improvement were detected using ISNCSCI motor and sensory scores. Our results support the safety of NSI-566 transplantation into the SCI site and early signs of potential efficacy in three of the subjects warrant further exploration of NSI-566 cells in dose escalation studies. Despite these encouraging secondary data, we emphasize that this safety trial lacks statistical power or a control group needed to evaluate functional changes resulting from cell grafting.

Survival of syngeneic and allogeneic iPSC-derived neural precursors after spinal grafting in minipigs.

The use of autologous (or syngeneic) cells derived from induced pluripotent stem cells (iPSCs) holds great promise for future clinical use in a wide range of diseases and injuries. It is expected that cell replacement therapies using autologous cells would forego the need for immunosuppression, otherwise required in allogeneic transplantations. However, recent studies have shown the unexpected immune rejection of undifferentiated autologous mouse iPSCs after transplantation. Whether similar immunogenic properties are maintained in iPSC-derived lineage-committed cells (such as neural precursors) is relatively unknown. We demonstrate that syngeneic porcine iPSC-derived neural precursor cell (NPC) transplantation to the spinal cord in the absence of immunosuppression is associated with long-term survival and neuronal and glial differentiation. No tumor formation was noted. Similar cell engraftment and differentiation were shown in spinally injured transiently immunosuppressed swine leukocyte antigen (SLA)-mismatched allogeneic pigs. These data demonstrate that iPSC-NPCs can be grafted into syngeneic recipients in the absence of immunosuppression and that temporary immunosuppression is sufficient to induce long-term immune tolerance after NPC engraftment into spinally injured allogeneic recipients. Collectively, our results show that iPSC-NPCs represent an alternative source of transplantable NPCs for the treatment of a variety of disorders affecting the spinal cord, including trauma, ischemia, or amyotrophic lateral sclerosis.

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.

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.

Subpial Adeno-associated Virus 9 (AAV9) Vector Delivery in Adult Mice.

The successful development of a subpial adeno-associated virus 9 (AAV9) vector delivery technique in adult rats and pigs has been reported on previously. Using subpially-placed polyethylene catheters (PE-10 or PE-5) for AAV9 delivery, potent transgene expression through the spinal parenchyma (white and gray matter) in subpially-injected spinal segments has been demonstrated. Because of the wide range of transgenic mouse models of neurodegenerative diseases, there is a strong desire for the development of a potent central nervous system (CNS)-targeted vector delivery technique in adult mice. Accordingly, the present study describes the development of a spinal subpial vector delivery device and technique to permit safe and effective spinal AAV9 delivery in adult C57BL/6J mice. In spinally immobilized and anesthetized mice, the pia mater (cervical 1 and lumbar 1-2 spinal segmental level) was incised with a sharp 34 G needle using an XYZ manipulator. A second XYZ manipulator was then used to advance a blunt 36G needle into the lumbar and/or cervical subpial space. The AAV9 vector (3-5 µL; 1.2 x 1013 genome copies (gc)) encoding green fluorescent protein (GFP) was then injected subpially. After injections, neurological function (motor and sensory) was assessed periodically, and animals were perfusion-fixed 14 days after AAV9 delivery with 4% paraformaldehyde. Analysis of horizontal or transverse spinal cord sections showed transgene expression throughout the entire spinal cord, in both gray and white matter. In addition, intense retrogradely-mediated GFP expression was seen in the descending motor axons and neurons in the motor cortex, nucleus ruber, and formatio reticularis. No neurological dysfunction was noted in any animals. These data show that the subpial vector delivery technique can successfully be used in adult mice, without causing procedure-related spinal cord injury, and is associated with highly potent transgene expression throughout the spinal neuraxis.