Comparison of SARS-CoV-2 entry inhibitors based on ACE2 receptor or engineered Spike-binding peptides.

With increasing resistance of SARS-CoV-2 variants to antibodies, there is interest in developing entry inhibitors that target essential receptor-binding regions of the viral Spike protein and thereby present a high bar for viral resistance. Such inhibitors could be derivatives of the viral receptor, ACE2, or peptides engineered to interact specifically with the Spike receptor-binding pocket. We compared the efficacy of a series of both types of entry inhibitors, constructed as fusions to an antibody Fc domain. Such a design can increase protein stability and act to both neutralize free virus and recruit effector functions to clear infected cells. We tested the reagents against prototype variants of SARS-CoV-2, using both Spike pseudotyped vesicular stomatitis virus vectors and replication-competent viruses. These analyses revealed that an optimized ACE2 derivative could neutralize all variants we tested with high efficacy. In contrast, the Spike-binding peptides had varying activities against different variants, with resistance observed in the Spike proteins from Beta, Gamma, and Omicron (BA.1 and BA.5). The resistance mapped to mutations at Spike residues K417 and N501 and could be overcome for one of the peptides by linking two copies in tandem, effectively creating a tetrameric reagent in the Fc fusion. Finally, both the optimized ACE2 and tetrameric peptide inhibitors provided some protection to human ACE2 transgenic mice challenged with the SARS-CoV-2 Delta variant, which typically causes death in this model within 7-9 days. IMPORTANCE The increasing resistance of SARS-CoV-2 variants to therapeutic antibodies has highlighted the need for new treatment options, especially in individuals who do not respond to vaccination. Receptor decoys that block viral entry are an attractive approach because of the presumed high bar to developing viral resistance. Here, we compare two entry inhibitors based on derivatives of the ACE2 receptor, or engineered peptides that bind to the receptor-binding pocket of the SARS-CoV-2 Spike protein. In each case, the inhibitors were fused to immunoglobulin Fc domains, which can further enhance therapeutic properties, and compared for activity against different SARS-CoV-2 variants. Potent inhibition against multiple SARS-CoV-2 variants was demonstrated in vitro, and even relatively low single doses of optimized reagents provided some protection in a mouse model, confirming their potential as an alternative to antibody therapies.

Cauda equina syndrome.

Aims: Patients with cauda equina syndrome (CES) require emergency imaging and surgical decompression. The severity and type of symptoms may influence the timing of imaging and surgery, and help predict the patient's prognosis. Categories of CES attempt to group patients for management and prognostication purposes. We aimed in this study to assess the inter-rater reliability of dividing patients with CES into categories to assess whether they can be reliably applied in clinical practice and in research. Methods: A literature review was undertaken to identify published descriptions of categories of CES. A total of 100 real anonymized clinical vignettes of patients diagnosed with CES from the Understanding Cauda Equina Syndrome (UCES) study were reviewed by consultant spinal surgeons, neurosurgical registrars, and medical students. All were provided with published category definitions and asked to decide whether each patient had 'suspected CES'; 'early CES'; 'incomplete CES'; or 'CES with urinary retention'. Inter-rater agreement was assessed for all categories, for all raters, and for each group of raters using Fleiss's kappa. Results: Each of the 100 participants were rated by four medical students, five neurosurgical registrars, and four consultant spinal surgeons. No groups achieved reasonable inter-rater agreement for any of the categories. CES with retention versus all other categories had the highest inter-rater agreement (kappa 0.34 (95% confidence interval 0.27 to 0.31); minimal agreement). There was no improvement in inter-rater agreement with clinical experience. Across all categories, registrars agreed with each other most often (kappa 0.41), followed by medical students (kappa 0.39). Consultant spinal surgeons had the lowest inter-rater agreement (kappa 0.17). Conclusion: Inter-rater agreement for categorizing CES is low among clinicians who regularly manage these patients. CES categories should be used with caution in clinical practice and research studies, as groups may be heterogenous and not comparable.

Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery, using clinician and participant reporting: A multi-centre prospective cohort study.

Background: Cauda equina syndrome (CES) results from nerve root compression in the lumbosacral spine, usually due to a prolapsed intervertebral disc. Evidence for management of CES is limited by its infrequent occurrence and lack of standardised clinical definitions and outcome measures. Methods: This is a prospective multi-centre observational cohort study of adults with CES in the UK. We assessed presentation, investigation, management, and all Core Outcome Set domains up to one year post-operatively using clinician and participant reporting. Univariable and multivariable associations with the Oswestry Disability Index (ODI) and urinary outcomes were investigated. Findings: In 621 participants with CES, catheterisation for urinary retention was required pre-operatively in 31% (191/615). At discharge, only 13% (78/616) required a catheter. Median time to surgery from symptom onset was 3 days (IQR:1-8) with 32% (175/545) undergoing surgery within 48 h. Earlier surgery was associated with catheterisation (OR:2.2, 95%CI:1.5-3.3) but not with admission ODI or radiological compression. In multivariable analyses catheter requirement at discharge was associated with pre-operative catheterisation (OR:10.6, 95%CI:5.8-20.4) and one-year ODI was associated with presentation ODI (r = 0.3, 95%CI:0.2-0.4), but neither outcome was associated with time to surgery or radiological compression. Additional healthcare services were required by 65% (320/490) during one year follow up. Interpretation: Post-operative functional improvement occurred even in those presenting with urinary retention. There was no association between outcomes and time to surgery in this observational study. Significant healthcare needs remained post-operatively. Funding: DCN Endowment Fund funded study administration. Castor EDC provided database use. No other study funding was received.

Anterior or posterior surgery for right thoracic adolescent idiopathic scoliosis (AIS)? A prospective cohorts' comparison using radiologic and functional outcomes.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: Prospectively compare patient-reported as well as clinical and radiologic outcomes after anterior or posterior surgery for right thoracic adolescent idiopathic scoliosis (AIS) in a single center by the same surgeons. SUMMARY OF BACKGROUND DATA: Anterior and posterior spinal instrumentation and arthrodesis are both well-established treatments of thoracic AIS. The majority of studies comparing the 2 approaches have focused on radiographic outcomes. There remains a paucity of prospectively gathered patient-reported outcomes comparing surgical approaches. METHODS: Forty-two consecutive patients with right thoracic AIS were treated in a single center by one of 2 surgeons with either anterior (n=18) or posterior (n=24) approaches and followed up for over 2 years. Radiographic, clinical, and patient-reported outcomes of the Modified Scoliosis Research Society Outcome Instrument were gathered and analyzed by an independent surgeon. RESULTS: Patients reported significant improvements in all areas of the Modified Scoliosis Research Society Outcome Instrument, especially pain and self-image domains. There were no significant differences in the degree of improvement in any domains between the groups. Posterior and anterior surgery corrected rib hump by 53% and 61%, respectively (P=0.4). The Main thoracic curve Cobb angle was corrected from 69 to 26 degrees (62%) by posterior surgery and 61 to 23 degrees (64%) by anterior surgery (P=0.6). Posterior surgery significantly reduced kyphosis and lumbosacral lordosis. Anterior surgery had no overall affect of sagittal alignment but seemed able to correct those hypokyphotic preoperatively. Complications differed and were largely approach-related--intrathoracic in anterior and wound-related in posterior surgery. CONCLUSIONS: Patients with right thoracic AIS of differing curve types but otherwise similar preoperatively demonstrated that anterior and posterior surgery are largely equivalent. Patient-reported outcomes are improved similarly by either approach. Both offer excellent radiographic and trunk deformity correction. Differences in the effect of sagittal alignment, operative time, and complications should be considered when selecting approach.

Tumor necrosis alpha-blocking agent (etanercept): a triple blind randomized controlled trial of its use in treatment of sciatica.

STUDY DESIGN: Triple blind randomized controlled study. OBJECTIVE: To establish the treatment effect of etanercept in acute sciatica secondary to lumbar disc herniation. SUMMARY OF BACKGROUND DATA: Etanercept is a selective competitor of tumor necrosis factor-alpha which is a proinflammatory cytokine. It is currently used alone or in combination with other medication for the treatment of chronic inflammatory disease. METHODS: Inclusion criteria were acute unilateral radicular leg pain secondary to herniated nucleus pulposus confirmed on magnetic resonance imaging scan. Exclusions were previous back surgery, spinal stenosis and any contraindications to the use of etanercept such as immunosuppression. The patient, the injector, and assessor were blinded to the agent being used. Follow-up was at 6 weeks and 3 months posttreatment. Oswestry disability index and visual analog scores were among the assessment criteria. RESULTS: Fifteen patients were recruited in a 4 years period with a 3 months follow-up of 80%. The etanercept group had 8 patients whereas the placebo group had 7. The average Oswestry disability index for the etanercept group preintervention was higher than that in the placebo group (53.6 vs. 50.4) and this remained the same after 6 weeks (46.1 vs. 31.2) and 3 months of follow-up (37 vs. 35). Visual analog score was also higher in the etanercept group versus placebo; preinjection (8.6 vs. 7.4), 6 weeks (5.0 vs. 3.8), and 3 months (4.8 vs. 4.5). CONCLUSIONS: Small numbers of trial participants limited statistical analysis. The trend appears to show no benefit to the use of etanercept over placebo in the pharmacologic treatment of sciatica.

Outcome scores in spinal surgery quantified: excellent, good, fair and poor in terms of patient-completed tools.

Outcome scores are very useful tools in the field of spinal surgery as they allow us to assess a patient's progress and the effect of various treatments. The clinical importance of a score change is not so clear. Although previous studies have looked at the minimum clinically important score change, the degree of score change varies considerably. Our study is a prospective cohort study of 193 patients undergoing discectomy, decompression and fusion procedures with minimum 2-year follow-up. We have used three standard outcome measures in common usage, the oswestry disability index (ODI), the low back outcome score (LBOS) and the visual analogue score (VAS). We have defined each of these scores according to a global measure of outcome graded by the patient as excellent, good, fair or poor. We have also graded patient perception and classified excellent and good as success and fair and poor as failure. Our results suggest that a median 24-point change in the ODI equates with a good outcome or is the minimum change needed for success. We have also found that different surgical disorders have very different minimal clinically important differences as perceived by patient perception. We found that for a discectomy a minimum 27-point change in the ODI would be classed as a success, for a decompression the change in ODI needed to class it as a success would be 16 points, whereas for a fusion the change in the ODI would be only 13 points. We believe that patient-rated global measures of outcome are of value and we have quantified them in terms of the standard outcome measures used in spinal surgery.

Incidental durotomy in lumbar spine surgery: incidence and management.

There is increasing awareness of the need to inform patients of common complications that occur during surgical procedures. During lumbar spine surgery, incidental tear of the dural sac and subsequent cerebrospinal fluid leak is possibly the most frequently occurring complication. There is no consensus in the literature about the rate of dural tears in spine surgery. We have undertaken this study to evaluate the incidence of dural tears among spine surgeons in the United Kingdom for commonly performed spinal procedures. Prospective data was gathered for 1,549 cases across 14 institutions in the United Kingdom. The results give us a baseline rate for the incidence of dural tears. The rate was 3.5% for primary discectomy, 8.5% for spinal stenosis surgery and 13.2% for revision discectomy. There was a wide variation in the actual and estimated rates of dural tears among the spine surgeons. The results confirm that prospective data collection by spine surgeons is the most efficient and accurate way to assess complication rates for spinal surgery.