Despite advances in treating acute spinal cord injury (SCI), measures to mitigate permanent neurological deficits in affected patients are limited. Augmentation of mean arterial blood pressure (MAP) to promote blood flow and oxygen delivery to the injured cord is one of the only currently available treatment options to potentially improve neurological outcomes after acute spinal cord injury (SCI). However, to optimize such hemodynamic management, clinicians require a method to measure and monitor the physiological effects of these MAP alterations within the injured cord in real-time. To address this unmet clinical need, we developed a series of miniaturized optical sensors and a monitoring system based on multi-wavelength near-infrared spectroscopy (MW-NIRS) technique for direct transdural measurement and continuous monitoring of spinal cord hemodynamics and oxygenation in real-time. We conducted a feasibility study in a porcine model of acute SCI. We also completed two separate animal studies to examine the function of the sensor and validity of collected data in an acute experiment and a seven-day post-injury survival experiment. In our first animal experiment, nine Yorkshire pigs underwent a weight-drop T10 vertebral level contusion-compression injury and received episodes of ventilatory hypoxia and alterations in MAP. Spinal cord hemodynamics and oxygenation were monitored throughout by a transdural NIRS sensor prototype, as well as an invasive intraparenchymal (IP) sensor as a comparison. In a second experiment, we studied six Yucatan miniature pigs that underwent a T10 injury. Spinal cord oxygenation and hemodynamics parameters were continuously monitored by an improved NIRS sensor over a long period. Episodes of MAP alteration and hypoxia were performed acutely after injury and at two- and seven-days post-injury to simulate the types of hemodynamic changes patients experience after an acute SCI. All NIRS data were collected in real-time, recorded and analyzed in comparison with IP measures. Noninvasive NIRS parameters of tissue oxygenation were highly correlated with invasive IP measures of tissue oxygenation in both studies. In particular, during periods of hypoxia and MAP alterations, changes of NIRS-derived spinal cord tissue oxygenation percentage were significant and corresponded well with the changes in spinal cord oxygen partial pressures measured by the IP sensors (p < 0.05). Our studies indicate that a novel optical biosensor developed by our team can monitor real-time changes in spinal cord hemodynamics and oxygenation over the first seven days post-injury and can detect local tissue changes that are reflective of systemic hemodynamic changes. Our implantable spinal cord NIRS sensor is intended to help clinicians by providing real-time information about the effects of hemodynamic management on the injured spinal cord. Hence, our novel NIRS system has the near-term potential to impact clinical care and improve neurologic outcomes in acute SCI. To translate our studies from bench to bedside, we have developed an advanced clinical NIRS sensor that is ready to be implanted in the first cohort of acute SCI patients in 2022

Introduction. Evidence suggests that intra-operative spinal cord monitoring is sensitive and specific for detecting potential neurological injury. However, little is known about surgeons' responses to trace changes and the resultant neurological outcome. Objective. To examine the role of intra-operative somatosensory evoked potential (SSEP) monitoring in the prevention of neurological injury, specifically sensitivity and specificity, and whether the abnormalities were reversible. Methods. 2953 consecutive complex spine operations (male 36% female 64%, median age 25yrs) prospectively performed using spinal cord monitoring at a single institution (2005–2009). All traces and neurophysiological events were prospectively recorded by the neurophysiology technician. All patients with a significant neurophysiology event were examined clinically by a neurologist, separate from the spinal surgery team. Significant trace abnormality was defined as a decrease in signal amplitude of 50% or a 10% increase in latency. Timing of trace abnormality, surgeon's response and prospective neurological outcome were recorded. Sensitivity, specificity, positive/negative predictive value were calculated. A Chi-squared test was performed to assess the impact of intervention on neurological outcome (p < 0.05). Results. 2953 operations involving SSEP monitoring were performed and 106 recorded a significant trace abnormality. This most often occurred during instrumentation and the most common reaction was adjustment of metalwork. SSEP monitoring had a sensitivity of 100%, specificity 97.3%, PPV 24%, NPV 100%. There were 79 false positives and no false negatives in this series. Chi-squared test was not significant (p=0.18) suggesting that intervention might not affect neurological outcome in this cohort. Conclusions. Triggering events are uncommon and the development of a persistent neurological deficit is rare with an incidence of 0.85% in this series of 2953 operations. In the majority of cases detection of a monitoring abnormality prompts a corrective reaction by the surgeon. Of those with an abnormal trace 76% were neurologically normal at follow up

National Institute of Clinical Excellence guidelines on Metastatic Spinal Cord Compression recommend urgent consideration of patients with spinal metastases and imaging evidence of structural spinal failure with spinal instability for surgery to stabilise the spine and prevent Metastatic Spinal Cord Compression. We aimed to compare neurological outcomes of patients managed operatively and non-operatively. Prospective collection of 397 patients' data over a 4-year period. Males represented 59.2% of patients. Median age was 69 years. Non-operative intervention in 62.2% of patients. Prostate, lung, Breast, Myeloma, Renal Cell Carcinoma and Lymphoma accounted for over 75% of all primary tumours (n=305). Median Length of hospital stay was longer in the operative group of 15 days compared to 10 days in the non-operative group (p<0.0001). Patients who were ambulating on presentation maintained their ambulation in 70.2% of cases in the operative group compared to 90.9% in the non-operative group (p<0.0001). However, upon discharge 41% of patients managed operatively were ambulatory compared to the non-operative group rate of 36.5% (p<0.0001). In Prostate, Breast, Myeloma, RCC and Lymphoma 100% of patients managed non-operatively maintained ambulation. Lung primaries managed operatively had an 80% chance of maintaining ambulation compared to 76.9% in the non-operative group (p<0.05). A higher proportion of patients managed non-operatively maintained ambulation than those managed operatively. With operative intervention, more patients regained ambulatory status. Whilst we have mainly focused on ambulatory status in this paper there are other factors to consider including pain relief and spinal stability which may be an indication for surgical intervention

Introduction. Somatosensory evoked potential (SSEP) monitoring allows for assessment of the spinal cord and susceptible structures during complex spinal surgery. It is well validated for the detection of potential neurological injury but little is known of surgeon's responses to an abnormal trace and its effect on neurological outcome. We aimed to investigate this in spinal deformity patients who are particularly vulnerable during their corrective surgery. Methods. Our institutional neurophysiology database was analysed between 1. st. October 2005 and 31. st. March 2010. Monitoring was performed by a team of trained neurophysiology technicians who were separate from the surgical team. A significant trace was defined as a 50% reduction in trace amplitude or a 10% increase in signal latency. Patients suffering a significant trace event were examined post-operatively by a Consultant Neurologist who was separate from the surgical team. Results. 2386 consecutive operations (F:1719, M:667 median age 16 yrs) were performed in the time period and 72 operations reported a significant trace event (‘red alert’). From these cases 47 (65%) had a clearly documented intervention by the surgeon and 7 patients overall suffered a lasting neurological deficit (0.3%). The most common timing events were during instrumentation (50%) and during correction/distraction (16%). Most common responses were optimisation of patient/monitoring set-up (23%) and adjustment of metalwork (22%). There were 18 wake-up tests performed. We found SSEP monitoring to have a sensitivity of 100%, specificity 97.4%, positive predictive value 14% and negative predictive value 100%. A Chi-square test (p=0.016) was significant suggesting intervention had a beneficial effect on neurological outcome. Conclusion. We would advocate the use of SSEP monitoring in all patients undergoing spinal deformity surgery. These patients tend to be young, neurologically intact pre-operatively and are particularly vulnerable to the large corrective forces their surgery requires

Background. There is minimal published data regarding the long-term functional outcome in pyogenic spinal infection. Previous studies have used heterogeneous, unreliable and non-validated measure instruments, or neurological outcome alone, yielding data that is difficult to interpret. We aim to assess long-term adverse outcome using standardised measures, Oswestry disability index (ODI) and MOS short form-36 (SF-36). Methods. All cases of pyogenic spinal infection presenting to a single institution managed operatively and non-operatively from 1994-2004 were retrospectively identified. Follow-up was by clinical review and standardised questionnaires. Inclusion in each case was on the basis of consistent clinical, imaging and microbiology criteria. Results. Twenty-nine cases of pyogenic spinal infection were identified. Twenty-eight percent were managed operatively and 72% with antibiotic therapy alone. Nineteen patients (66%) had an adverse outcome at a median follow-up of 61 months, despite only 5 patients (17%) having persistent neurological deficit. A significant difference in SF-36 PF (physical function) scores was observed between patients with adverse outcome and patients who recovered (p=0.003). SF-36 scores of all patients, regardless of management or outcome, failed to reach those of a normative population. A strong correlation was observed between ODI and SF-36 PF scores (rho=0.61, p<0.05). Seventeen percent (n=5) of admissions resulted in acute sepsis-related death. Subgroup analysis revealed delay in diagnosis of spinal infection (p=0.025) and neurological impairment at diagnosis (p<0.001) to be significant predictors of neurological deficit at follow-up. Previous spinal surgery was associated with adverse outcome in patients requiring readmission within 1 year of hospital discharge following first spinal infection (p=0.018). No independent predictors of adverse outcome, persistent neurological impairment, readmission within 1 year or acute death were identified by logistical regression analysis. Conclusions. High rates of adverse outcome detected using SF-36 and ODI suggest under-reporting of poor outcome when ASIA score alone is used to qualify outcome

The optimal management of patients with the diagnosis of a spinal epidural abscess (SEA) remains controversial. The purpose of this study was to describe the clinical characteristics of patients presenting with spontaneous SEA and to correlate presentation and treatment with clinical and neurological outcome. A retrospective review of the medical records and radiology of patients with a diagnosis of SEA, treated between September 2003 and December 2010, at a tertiary referral hospital was performed. A total of 46 patients were identified including 27 males and 19 females. Mean age was 61 years (range, 30 – 86 years). At presentation, all patients had axial pain and 67% had a neurological deficit, out of which one third had paraplegia or quadriplegia. 32% patients were febrile. Diabetes was the most common risk factor (30%) followed by malignancy (17%), intravenous drug use (6%) and alcoholism (2%). Organisms were cultured in 44 patients with Methicillin Sensitive Staphylococcus Aureus most common (68%), followed by Methicillin Resistant Staphylococcus Aureus (14%). The epidural abscess was located in the lumbar spine in 24 patients, thoracic spine in 11 patients and cervical spine in 11 patients. 61% of patients had a concurrent source of septic focus on presentation, including psoas abscess (24%), facet joint septic arthritis (15%), pneumonia (11%), infective endocarditis (7%) and urosepsis (4%). 26% of patients were treated non-operatively, with computed tomography-guided aspiration and/or intravenous antibiotics based on cultures, whereas 74% underwent surgical decompression with or without fusion in combination with antibiotics. The mean inpatient hospital stay was 42 days (range, 2 – 742 days) and 34% of patients required an average of 40 days of Intensive Care Unit admission. At time discharge from hospital, of the patients managed nonoperatively, 33% had improved neurological function, 17% had worsened neurological function, 17% died and data was unavailable in 33%. Of the patients treated with surgery, 74% had improved neurological function, 6% remained unchanged, 6% had worsened neurologic function, 6% died and data was unavailable in 9% at time of discharge. SEA remains a severe condition associated with multiple septic foci and significant morbidity. Surgical decompression combined with antibiotics is associated with superior neurologic recovery compared with non-operative management, however a significant proportion of patients still deteriorate or die. Early diagnosis and management may prevent or reduce permanent neurologic deficit