Two-stage surgery for large sacrococcygeal chordomas: How I do it.

Sacrococcygeal chordoma is a malignant, slow-growing, and locally aggressive bone tumor. A wide surgical margin is recommended to prevent local recurrence and metastasis. This disease tends to cause massive defects when rectal resection and sacrectomy are required. Therefore, soft tissue reconstruction is required and a pedicled vertical rectus abdominis muscle flap (VRAM) is a viable option. Important anatomical landmarks, advantages and limitations are discussed and the procedure is described step by step. This case report presents a two-stage operation with an anterior rectal resection and VRAM flap harvest followed by a complementary posterior approach with sacrectomy and soft tissue reconstruction: approach and results. The wound completely healed in six weeks. Three years after surgery, no local recurrence or distal metastasis was detected. This two-stage strategy presents a viable and safe option for large sacrococcygeal chordomas.

Additive Manufactured Piezoelectric-Driven Miniature Gripper.

In several cases, it is desirable to have prototypes of low-cost fabrication and adequate performance. In academic laboratories and industries, miniature and microgrippers can be very useful for observations and the analysis of small objects. Piezoelectrically actuated microgrippers, commonly fabricated with aluminum, and with micrometer stroke or displacement, have been considered as Microelectromechanical Systems (MEMS). Recently, additive manufacture using several polymers has also been used for the fabrication of miniature grippers. This work focuses on the design of a piezoelectric-driven miniature gripper, additive manufactured with polylactic acid (PLA), which was modeled using a pseudo rigid body model (PRBM). It was also numerically and experimentally characterized with an acceptable level of approximation. The piezoelectric stack is composed of widely available buzzers. The aperture between the jaws allows it to hold objects with diameters lower than 500 µm, and weights lower than 1.4 g, such as the strands of some plants, salt grains, metal wires, etc. The novelty of this work is given by the miniature gripper's simple design, as well as the low-cost of the materials and the fabrication process used. In addition, the initial aperture of the jaws can be adjusted, by adhering the metal tips in the required position.

Structural characterization, stability, and cytocompatibility study of chitosan BaTiO3@ZnO:Er heterostructures.

New imaging agents are required in cancer diagnosis to enhance the diagnostic accuracy, classification, and therapeutic management of tumors. Nanomaterials have emerged as a promising alternative to developing new nanostructures with imaging applications. In this study, a heterostructure based on barium titanate (BT), zinc oxide (ZnO), and erbium (Er) was prepared and coated with Chitosan (CS) to investigate their stability and compatibility with biological systems. The structure, particle morphology, luminescence properties, stability, and cytotoxicity of different nanoparticles (NPs) were assessed. The results demonstrated the formation of a [BT@ZnO:Er]-CS heterostructure, which is consistent with the relative intensities and positions of peaks in the X-ray diffraction (XRD) with an average crystallite size of ~76 nm. The electrokinetic measurement results indicate that the coated NPs are the most stable and have an average size close to 200 nm when the pH is between 3 and 5. Finally, we presented a cytotoxicity study of naked and CS-coated NPs. The results indicate that naked NPs exhibit varying cellular toxicity, as indicated by decreased cell viability, morphological changes, and an increase in an apoptotic marker. The CS-coated NPs prevented the cytotoxic effect of the naked NPs, demonstrating the significance of CS as a stabilizing agent.

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients.

PURPOSE: Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies. METHODS: The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed. RESULTS: Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02). CONCLUSION: Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Nocardia farcinica cerebral abscess: A systematic review of treatment strategies.

PURPOSE: Nocardia farcinica is an opportunistic pathogen causing mainly pneumonia in immunocompromised patients, complicated in almost one-third of the cases by a thick-walled multiloculated cerebral abscess which induces significant morbidity and mortality. This review aims to assess the optimal treatment strategy for N. farcinica cerebral abscess. METHODS: Report of a case. Medline database was used to conduct a systematic review from inception to January 2020 looking for English-language articles focused on N. farcinica cerebral abscess, in accordance with the PRISMA guidelines. RESULTS: The research yielded 54 articles for a total of 58 patients. N. farcinica cerebral abscess displayed three different neuroimaging patterns: a single multiloculated abscess in half of the cases, multiple cerebral abscesses, or a small paraventricular abscess with meningitis. The patients who benefited from surgical excision of the abscess showed a trend towards a lower risk of surgical revision (8% versus 31%, P=0.06) and a lower mortality rate (8% versus 23%, P=0.18) than patients who benefited from needle aspiration. Twenty-two percent of the patients benefited from microbiological documentation from another site with a mortality rate of 23%. CONCLUSION: Urgent multimodal MRI is necessary in face with clinical suspicion of cerebral nocardiosis. In case of single or multiple small cerebral abscesses, microbiological documentation can be obtained with puncture of pseudotumoral visceral lesions. In case of large or symptomatic cerebral abscess, an aggressive surgical excision seems a reliable option and can be preferred over needle aspiration. Long-term antibiotic therapy with cotrimoxazole is necessary thereafter.

Surgery for spinal deformity in Parkinson's disease patients: What are we missing?

INTRODUCTION: Deformity associating coronal and sagittal malalignment can severely impair quality of life in Parkinson's disease (PD). Realignment using patient-specific rods (PSRs) is useful for achieving alignment goals. METHODS: This was a retrospective single-center analysis of a prospectively maintained database of all PD patients who underwent surgery between January 2013 and January 2017. Clinical evaluation, preoperatively and at 1 year's follow-up, used the Oswestry Disability Index (ODI). Radiological evaluation used systematic preoperative and 1-year postoperative full-spine radiographs. RESULTS: Twelve patients were included: 6 female, 6 male; mean age, 68.4 years. Mean follow-up was 40.8 months [range 12-70]. On average, 14 levels were fused [range 10-18]. Unplanned revision surgery was necessary for 8 patients at a mean 15.625 months after index surgery. Mean preoperative ODI score was 64% preoperatively [range 56-70] versus 52% [range 28-64] at 1 year's follow-up (P=0.004). Lumbar lordosis improved significantly, from -16.7° preoperatively to -41.4° at 1 year (P=0.006). Pelvic tilt was the least effectively corrected parameter, with a mean preoperative value of 31.6° vs. 27.8° at 1 year (P=0.19). Mean preoperative sagittal vertical axis was 149.7mm versus 73.6mm at 1 year (P=0.013). Mean preoperative coronal tilt was 68.2mm versus 22.9mm at 1 year (P=0.007). CONCLUSION: Parkinson's disease is a degenerative disease frequently associated with major spine malalignment. The severity of the postural disorders in these patients needs special precautions to avoid complications.

[Sudden unexpected death in infancy: Update and preventive measures]. / Muerte súbita inesperada en la infancia: Actualización y medidas de prevención.

Sudden unexpected death in infancy (SUDI) - defined as the death of a child under 1 year of age du ring sleep with no initially obvious cause - remains one of the most common causes of post-neonatal mortality. Approximately 3,500 infants die annually in the United States from sleep-related deaths. A complex and multifactorial origin is postulated in a vulnerable infant. However, the pathophysiology of SUDI has not been fully understood. Health care providers play a key role in promoting preventive measures described in the literature, which include sleeping in a supine position on a firm surface, avoiding smoking and co-sleeping, promoting breastfeeding, among others. The objective of this re view is to summarize the main epidemiological and physiopathological characteristics of SUDI, and safe sleep-related factors.

A mathematical modelling framework for the regulation of intra-cellular OCT4 in human pluripotent stem cells.

Human pluripotent stem cells (hPSCs) have the potential to differentiate into all cell types, a property known as pluripotency. A deeper understanding of how pluripotency is regulated is required to assist in controlling pluripotency and differentiation trajectories experimentally. Mathematical modelling provides a non-invasive tool through which to explore, characterise and replicate the regulation of pluripotency and the consequences on cell fate. Here we use experimental data of the expression of the pluripotency transcription factor OCT4 in a growing hPSC colony to develop and evaluate mathematical models for temporal pluripotency regulation. We consider fractional Brownian motion and the stochastic logistic equation and explore the effects of both additive and multiplicative noise. We illustrate the use of time-dependent carrying capacities and the introduction of Allee effects to the stochastic logistic equation to describe cell differentiation. We conclude both methods adequately capture the decline in OCT4 upon differentiation, but the Allee effect model has the advantage of allowing differentiation to occur stochastically in a sub-set of cells. This mathematical framework for describing intra-cellular OCT4 regulation can be extended to other transcription factors and developed into predictive models.

High level of HIV drug resistance informs dolutegravir roll-out and optimized NRTI backbone strategy in Mozambique.

BACKGROUND: HIV drug resistance (HIV-DR) is rising in sub-Saharan Africa in both ART-naive and ART-experienced patients. OBJECTIVES: To estimate the level of acquired DR (ADR) and pre-treatment DR (PDR) across selected urban and rural sites in Southern Africa, in Mozambique. METHODS: We conducted two cross-sectional surveys among adult HIV patients (October 2017-18) assessing ADR and PDR. In the (ADR) survey, those on NNRTI-based first-line ART for ≥6 months were recruited (three sites). In the PDR survey, those ART-naive or experienced with ≥3 months of treatment interruption prior were enrolled (eight sites). RESULTS: Among 1113 ADR survey participants 83% were receiving tenofovir (TDF)/lamivudine (3TC)/efavirenz (EFV). The median time on ART was 4.5 years (Maputo) and 3.2 years (Tete), 8.3% (95% CI 6.2%-10.6%, Maputo) and 15.5% (Tete) had a VL ≥ 1000 copies/mL, among whom 66% and 76.4% had NNRTI+NRTI resistance, and 52.8% and 66.7% had 3TC+TDF-DR. Among those on TDF regimens, 31.1% (Maputo) and 42.2% (Tete) were still TDF susceptible, whereas 24.4% and 11.5% had TDF+zidovudine (ZDV)-DR. Among those on ZDV regimens, 25% and 54.5% had TDF+ZDV-DR. The PDR survey included 735 participants: NNRTI-PDR was 16.8% (12.0-22.6) (Maputo) and 31.2% (26.2-36.6) (Tete), with a higher proportion (≥50%) among those previously on ART affected by PDR. CONCLUSIONS: In Mozambique, viral failure was driven by NNRTI and NRTI resistance, with NRTI DR affecting backbone options. NNRTI-PDR levels surpassed the WHO 10% 'alert' threshold. Replacing NNRTI first-line drugs is urgent, as is frequent viral load monitoring and resistance surveillance. Changing NRTI backbones when switching to second-line regimens may need reconsideration.

Optimal Correction of Adult Spinal Deformities Requires Restoration of Distal Lumbar Lordosis.

PURPOSE: The aim of this study is to analyze results according to postoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch in the management of adult spine deformity (ASD) patients. Recently, it has been reported that in addition to lumbar lordosis amount, lordosis repartition between its proximal and distal parts was crucial. METHODS: We enrolled 77 consecutive ASD patients who underwent posterior spinal fusion and deformity correction between 2015 and 2018. On preoperative and 1-year follow-up radiographs, we analyzed different parameters such as L1-S1 lumbar lordosis, L1-L4 proximal lordosis (PLL), L4-S1 distal lordosis (DLL), pelvic tilt (PT), sagittal vertical axis (SVA), and PI-LL mismatch. Comparisons were performed according to postoperative PI-LL mismatch (defined as "aligned" when PI-LL was <10°). The relationship between lordosis distribution and postoperative alignment status was investigated. RESULTS: On the whole series, average lumbar lordosis, SVA, and PI-LL improved (28.2° vs.43.5°, 82 vs. 51 mm, and 26°vs. 14°, all p < 0.001, respectively). On the other hand, PT remained unchanged (30° vs. 28°, p > 0.05). 35 patients were classified as "aligned" and 42 as "not aligned." Patients from the "aligned" group had a significantly lower PI than patients from the "not aligned" group (52° vs. 61°, p=0.009). Postoperative PLL was not different between groups (18° vs. 16° p > 0.05), whereas DLL was significantly higher in the "aligned" group (31° vs. 22°, p=0.003). PI-LL was significantly correlated to DLL (rho = 0.407, p < 0.001) but not with PLL (rho = 0.110, p=0.342). CONCLUSIONS: Our results revealed that in ASD patients, postoperative malalignment was associated with a lack of DLL restoration. "Not aligned" patients had also a significantly higher pelvic incidence. Specific attention must be paid to restore optimal distal lumbar lordosis in order to set the amount and the distribution of optimal postoperative lumbar lordosis.

Meningiomas in patients with long-term exposition to progestins: Characteristics and outcome.

OBJECTIVE: The aim of this study was to describe progestin-associated meningiomas' characteristics, outcome and management. MATERIAL AND METHODS: We included 53 patients operated on and/or followed in the department for meningioma with progestin intake longer than one year and with recent drug discontinuation. RESULTS: Cyproterone acetate (CPA), nomegestrol acetate (NomA), and chlormadinone acetate (ChlA) were involved in most cases. Mean duration of progestin drugs intake was 17.5 years. Tumors were multiple in 66% of cases and were located in the anterior and the medial skull base in 71% of cases. Transitional subtype represented 16/25 tumors; 19 meningiomas were WHO grade I and 6 were grade II. The rate of transitional subtype and skull base location was significantly higher compared to matched operated meningioma general population. No difference was observed given WHO classification. But Ki67 proliferation index tends to be lower and 5/6 of the WHO grade II meningiomas were classified as WHO grade II because of brain invasion. Strong progesterone receptors expression was observed in most cases. After progestin discontinuation, a spontaneous visual recovery was observed in 6/10 patients. Under CPA (n=24) and ChlA/NomA (n=11), tumor volume decreased in 71% and 18% of patients, was stabilized in 25% and 64% of patients, and increased in 4% and 18% of patients, respectively. Volume outcome was related to meningioma location. CONCLUSIONS: Outcome at progestins discontinuation is favorable but different comparing CPA versus ChlA-NomA and comparing tumor location. Long-term follow-up is required. In most cases, simple observation is recommended and surgery should be avoided.

Synthesis, Characterization and Optical Properties of ZnO Nanoparticles Doped with Er and Yb.

This paper discusses the structure, particle morphology, and optical properties of un-doped ZnO and ZnO doped with Er3+ and Yb3+ lanthanide ion nanoparticles (NPs) through a process denominated sol-gel-hydrothermal. According to the pattern of X-ray diffraction, ZnO:Er and ZnO:Yb is formed by a single-phase wurtzite structure with crystallites sized ~65 nm on average, and Er or Yb dopant ions in the hexagonal structure of ZnO, specifically in its distorted lattice sites. The results also suggest the possible role of oxygen vacancies or Ox- (defects) in the energy transfer from ZnO to the Er or Yb ions with a decrease of 3.18 eV and 3.19 eV in bandgap values to a red shift.

PICA injury secondary to anterior odontoid screw fixation: Case report of an exceptional complication.

BACKGROUND: Odontoid fracture is a common injury in the upper cervical spine that can sometimes be managed by anterior odontoid screw fixation. CASE DESCRIPTION: We report the first case of iatrogenic postero-inferior cerebellar artery (PICA) injury while performing anterior odontoid screw fixation for a type II odontoid fracture in a 22-year-old man. Fisher grade 4 subarachnoid hemorrhage secondary to iatrogenic pseudoaneurysm formation was managed by the endovascular neuroradiologist. Odontoid fracture was then managed posteriorly using Harm's technique. Postoperative 12-month follow-up revealed good clinical and radiological results. CT scan showed fusion. Complete exclusion of the pseudo aneurysm with a mild stroke in the inferior left cerebellar hemisphere were noted on the MRI. There were no cerebellar ataxia or swallowing disorders. CONCLUSION: To the best of our knowledge, this is the first case report of iatrogenic PICA injury in anterior odontoid screw fixation. The patient was well managed in our institution within a multidisciplinary team. We recommend that surgical management of odontoid fractures should be performed in expert centres.

C1-C2 Injury: Factors influencing mortality, outcome, and fracture healing.

BACKGROUND: C1-C2 injury represents 25-40% of cervical injuries and predominantly occurs in the geriatric population. METHODS: A prospective multicentre study was conducted under the aegis of the french spine surgery society (SFCR) investigating the impact of age, comorbidities, lesion type, and treatment option on mortality, complications, and fusion rates. RESULTS: A total of 417 patients were recruited from 11 participating centres. The mean ± SD age was 66.6 ± 22 years, and there were 228 men (55%); 5.4% presented a neurological deficit at initial presentation. The most frequent traumatic lesion was C2 fracture (n = 308). Overall mortality was 8.4%; it was 2.3% among those aged ≤ 60 years, 5.0% 61-80 years, and 16.0% > 80 years (p < 0.001). Regarding complications, 17.8% of patients ≤ 70 years of age presented with ≥ 1 complication versus 32.3% > 70 years (p = 0.0009). The type of fracture did not condition the onset of complications and/or mortality (p > 0.05). The presence of a comorbidity was associated with a risk factor for both death (p = 0.0001) and general complication (p = 0.008). Age and comorbidities were found to be independently associated with death (p < 0.005). The frequency of pseudoarthrosis ranged from 0 to 12.5% up to 70 years of age and then constantly and progressively increased to reach 58.6% after 90 years of age. CONCLUSIONS: C1-C2 injury represents a serious concern, possibly life-threatening, especially in the elderly. We found a major impact of age and comorbidities on mortality, complications, and pseudarthrosis; injury pattern or treatment option seem to have a minimal effect.

OCT4 expression in human embryonic stem cells: spatio-temporal dynamics and fate transitions.

The improved in vitro regulation of human embryonic stem cell (hESC) pluripotency and differentiation trajectories is required for their promising clinical applications. The temporal and spatial quantification of the molecular interactions controlling pluripotency is also necessary for the development of successful mathematical and computational models. Here we use time-lapse experimental data of OCT4-mCherry fluorescence intensity to quantify the temporal and spatial dynamics of the pluripotency transcription factor OCT4 in a growing hESC colony in the presence and absence of BMP4. We characterise the internal self-regulation of OCT4 using the Hurst exponent and autocorrelation analysis, quantify the intra-cellular fluctuations and consider the diffusive nature of OCT4 evolution for individual cells and pairs of their descendants. We find that OCT4 abundance in the daughter cells fluctuates sub-diffusively, showing anti-persistent self-regulation. We obtain the stationary probability distributions governing hESC transitions amongst the different cell states and establish the times at which pro-fate cells (which later give rise to pluripotent or differentiated cells) cluster in the colony. By quantifying the similarities between the OCT4 expression amongst neighbouring cells, we show that hESCs express similar OCT4 to cells within their local neighbourhood within the first two days of the experiment and before BMP4 treatment. Our framework allows us to quantify the relevant properties of proliferating hESC colonies and the procedure is widely applicable to other transcription factors and cell populations.

Surgical site infection following surgery for spinal deformity: About 102 patients.

INTRODUCTION: Complex spinal surgery is known to be at risk of complications. Surgical site infection is a serious complication in spine surgery and its frequency is significantly increased in adult spinal deformity correction. The aim of this study is to identify patients' characteristics and risk factors of surgical site infection (SSI) following an osteotomy. METHODS: This is a single-center retrospective study of patients who underwent an osteotomy between January 2015 and December 2017. Surgical site infection diagnosis was based upon patient's clinical evidence of infection, biologic parameters, microbiological criteria and/or image findings. RESULTS: In total, 102 patients were eligible and 70 were women (68.6%). Mean age was 65 years old (27-83 years) and mean body mass index (BMI) was 26.14kg.m-2 (18.4-44.1). Eleven patients were in the SSI group and 91 in the No-SSI group. The mean Schwab grade was 1.5 (1-4) in the SSI group vs. 1.4 (1-5) in the No-SSI group (P=0.435). The mean operative time was on 201.9 minutes (67-377). Mean length of stay was 20.6 days (10-73) in the SSI group vs. 15 days (5-44) in the No-SSI group (P=0.041). Favorable outcome was found in 10 patients (90.9%) in the SSI group. CONCLUSION: Correction surgery for adult spinal deformity with osteotomies carries a high risk of complications specially SSI. Identification of risk factors, prevention and medical management of SSI should be well assessed.

The recent advances in the mathematical modelling of human pluripotent stem cells.

Human pluripotent stem cells hold great promise for developments in regenerative medicine and drug design. The mathematical modelling of stem cells and their properties is necessary to understand and quantify key behaviours and develop non-invasive prognostic modelling tools to assist in the optimisation of laboratory experiments. Here, the recent advances in the mathematical modelling of hPSCs are discussed, including cell kinematics, cell proliferation and colony formation, and pluripotency and differentiation.