Evaluation of prognostic preoperative factors in patients undergoing surgery for spinal metastases: Results in a consecutive series of 81 cases

Background: Surgical treatment of spinal metastases should be tailored to provide pain control, neurological deficit improvement, and vertebral stability with low operative morbidity and mortality. The aim of this study was to analyze the predictive value of some preoperative factors on overall survival in patients undergoing surgery for spinal metastases. Methods: We retrospectively analyzed a consecutive series of 81 patients who underwent surgery for spinal metastases from 2015 and 2021 in the Clinic of Neurosurgery of Ancona (Italy). Data regarding patients’ baseline characteristics, preoperative Karnofsky Performance Status Score (KPS), and Frankel classification grading system, histology of primary tumor, Tokuhashi revised and Tomita scores, Spine Instability Neoplastic Score, and Epidural Spinal Cord Compression Classification were collected. We also evaluated the interval time between the diagnosis of the primary tumor and the onset of spinal metastasis, the type of surgery, the administration of adjuvant therapy, postoperative pain and Frankel grade, and complications after surgery. The relationship between patients’ overall survival and predictive preoperative factors was analyzed by the Kaplan–Meier method. For the univariate and multivariate analysis, the log-rank test and Cox regression model were used. P ≤ 0.05 was considered as statistically significant. Results: After surgery, the median survival time was 13 months. In our series, the histology of the primary tumor (P < 0.001), the Tomita (P < 0.001) and the Tokuhashi revised scores (P < 0.001), the preoperative KPS (P < 0.001), the adjuvant therapy (P < 0.001), the postoperative Frankel grade (P < 0.001), and the postoperative pain improvement (P < 0.001) were significantly related to overall survival in the univariate analysis. In the multivariate analysis, the Tomita (P < 0.001), Tokuhashi revised scores (P < 0.001), and the adjuvant therapy were confirmed as independent prognostic factors. Conclusion: These data suggest that patients with limited extension of primitive tumor and responsive to the adjuvant therapy are the best candidates for surgery with better outcome

Best Practices on QM/MM Simulations of Biological Systems

During the second half of the 20th century, following structural biology hallmark works on DNA and proteins, biochemists shifted their questions from “what does this molecule look like” to “how does this process work”. Prompted by the theoretical and practical developments in computational chemistry, this led to the emergence of biomolecular simulations and, along with the 2013 Nobel Prize in Chemistry, to the development of hybrid QM/MM methods. QM/MM methods are necessary whenever the problem we want to address involves chemical reactivity and/or a change in the system’s electronic structure, with archetypal examples being the studies of an enzyme’s reaction mechanism and a metalloprotein’s active site. In the last decades QM/MM methods have seen an increasing adoption driven by their incorporation in widely used biomolecular simulation software. However, properly setting up a QM/MM simulation is not an easy task, and several issues need to be properly addressed to obtain meaningful results. In the present work, we describe both the theoretical concepts and practical issues that need to be considered when performing QM/MM simulations. We start with a brief historical perspective on the development of these methods and describe when and why QM/MM methods are mandatory. Then we show how to properly select and analyze the performance of the QM level of theory, the QM system size, and the position and type of the boundaries. We show the relevance of performing prior QM model system (or QM cluster) calculations in a vacuum and how to use the corresponding results to adequately calibrate those derived from QM/MM. We also discuss how to prepare the starting structure and how to select an adequate simulation strategy, including those based on geometry optimizations as well as free energy methods. In particular, we focus on the determination of free energy profiles using multiple steered molecular dynamics (MSMD) combined with Jarzynski’s equation. Finally, we describe the results for two illustrative and complementary examples: the reaction performed by chorismate mutase and the study of ligand binding to hemoglobins. Overall, we provide many practical recommendations (or shortcuts) together with important conceptualizations that we hope will encourage more and more researchers to incorporate QM/MM studies into their research projects.Fil: Clemente, Camila Mara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Capece, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Marti, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

Managing ventriculoperitoneal shunt exposure in adult patients: surgical options and implant removal prevention

Background: Ventriculoperitoneal shunt exposure is rare. Small series reporting on managing this complication mainly focus on the pediatric population, where wound breaks over cerebrospinal fluid (CSF) chambers are observed most frequently. However, case series on adult patients are missing. Methods: Between June 2004 and December 2019, 18 patients underwent ventriculoperitoneal shunt revision due to implant exposure. Pertinent data were retrospectively collected from the hospital database. Their full clinical history, laboratory values, neuroradiological imaging, pre-treatment CSF characteristics, photographic and video material, and surgery types were reviewed. Results: The ventricular catheter was exposed in eight patients (the frontal region in six and the occipital region in two), the valve chamber at the retroauricular region in six, the shunt tube in seven (at the neck in four, the supraclavicular region in two, and the abdominal incision in one). Multiple exposure sites were found in two cases. Two patients with CSF infections benefitted from system removal and temporary external ventricular drainage until infection control was achieved. The remaining 16 patients underwent on-ward revision (wound curettage, skin mobilisation, and re-suture over the exposed part of the shunt), which was effective in 14 patients, but further revision was required in two patients. Conclusions: While rare, ventriculoperitoneal shunt exposure is a serious complication. In our experience, a prompt and accurate on-ward revision could save the implant in most patients without CSF infections

Laminectomy versus Unilateral Hemilaminectomy for the Removal of Intraspinal Schwannoma: Experience of a Single Institution and Review of Literature

Background and Study Aims Spinal schwannomas are benign slow-growing tumors, and gross total resection is the gold standard of treatment. The conventional surgical approach is laminectomy, which provides a wide working area. Today minimally invasive surgery (MIS) is popular because it is associated with shorter hospital stay, less operative blood loss, minimized tissue traumas and relative postoperative pain, and, and spine surgery, avoidance of spinal instability. Material and Methods From January 2016 to December 2019, we operated on 40 patients with spinal intradural extramedullary tumor (schwannoma) with laminectomy or hemilaminectomy. Baseline medical data, including patients' sex and age, tumor location, days of postoperative bed rest, operative time, length of hospitalization, and 1-month visual analog scale (VAS) value were collected and analyzed. Data analysis was performed using STATA/IC 13.1 statistical package (StataCorp LP, College Station, Texas, United States). Results Hemilaminectomy was associated with faster operative time (p < 0.001), shorter postoperative time spent in bed (p < 0.001), and shorter hospitalization (p < 0.001). At 1-month follow-up, the mean VAS score was 4.6 (1.7) among the laminectomy patients and 2.5 (1.3) among the hemilaminectomy patients (p < 0.001). Postoperative complications occurred in 1 (7.7%) and 7 (25.9%) patients in the hemilaminectomy and laminectomy groups, respectively (p = 0.177). Conclusions Unilateral hemilaminectomy has significant advantages compared with laminectomy in spinal schwannoma surgery including shorter operative time, less time spent in bed, shorter hospitalization, and less postoperative pain. © 2021 Georg Thieme Verlag. All rights reserved

The relationship between preoperative predictive factors for clinical outcome in patients operated for lumbar spinal stenosis by decompressive laminectomy

ABSTRACT Background: Our hypothesis was that by identifying certain preoperative predictive factors, we could favorably impact clinical outcomes in patients undergoing decompressive surgery for lumbar spinal stenosis (LSS). Methods: In this retrospective study, there were 65 patients (2016–2018) with symptomatic LSS who underwent decompressive laminectomy without fusion. Their clinical outcomes were assessed utilizing the Oswestry Disability Index (ODI). Multiple preoperative variables were studied to determine which ones would help predict improved outcomes: gender, age, body mass index (BMI), general/neurological examination, smoking, and drug therapies (anxiolytics and/or antidepressants). Results: All patients demonstrated statistically significant improvement on the ODI. Multivariate analysis revealed that those with higher preoperative BMI had significantly lower ODI on 1-year follow-up examinations, reflecting poorer outcomes. Postoperatively, 44 patients (67%) exhibited lower utilization of anxiolytic medications, 52 patients (80%) showed reduced use of antidepressant drugs, and pain medications utilization was reduced in 33 patients (50%). Conclusion: Decompressive laminectomy without fusion effectively managed LSS. It reduced patients’ use of pain, anxiety, and antidepressant medications. In addition, we found that increased preoperative BMIs contributed to poorer postoperative outcomes (e.g., ODI values)

Respiratory function in a large cohort of treatment-naïve adult spinal muscular atrophy patients: a cross-sectional study

: Due to poor data in literature, we aimed to investigate the respiratory function in a large cohort of naïve Italian adult (≥18 years) SMA patients in a multi-centric cross-sectional study. The following respiratory parameters were considered: forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and need for non-invasive ventilation (NIV). We included 145 treatment-naïve adult patients (SMA2=18, SMA3=125; SMA4=2), 58 females (40 %), with median age at evaluation of 37 years (range 18-72). Fifty-six (37 %) and 41 (31 %) patients had abnormal (<80 %) values of FVC and FEV1, respectively. Fourteen (14 %) patients needed NIV, started at median age of 21 (range 4-68). Motor function, measured by Hammersmith Functional Motor Scale Expanded and Revised Upper Limb Module as well as SMA2, loss of walking ability, surgery for scoliosis, use of NIV, and cough assisting device (CAD) were all significantly associated to lower FVC and FEV1 values, while no association with age at baseline, disease duration, gender or 6 min walking test was observed, except for a correlation between FVC and age in SMA3 walkers (p < 0.05). In conclusion, respiratory function in adult SMA patients is relatively frequently impaired, substantially stable, and significantly correlated with motor function and disease severity