Variations in surgical practice and short-term outcomes for degenerative lumbar scoliosis and spondylolisthesis: do surgeon training and experience matter?

For diverse procedures, sizable geographic variation exists in rates and outcomes of surgery, including for degenerative lumbar spine conditions. Little is known about how surgeon training and experience are associated with surgeon-level variations in spine surgery practice and short-term outcomes. This retrospective observational analysis characterized variations in surgical operations for degenerative lumbar scoliosis or spondylolisthesis, two common age-related conditions. The study setting was two large spine surgery centers in one region during 2017-19. Using data (International Classification of Diseases-10th edition and current procedural terminology codes) extracted from electronic health record systems, we characterized surgeon-level variations in practice (use of instrumented fusion - a more extensive procedure that involves device-related risks) and short-term postoperative outcomes (major in-hospital complications and readmissions). Next, we tested for associations between surgeon training (specialty and spine fellowship) and experience (career stage and operative volume) and use of instrumented fusion as well as outcomes. Eighty-nine surgeons performed 2481 eligible operations. For the study diagnoses, spine surgeons exhibited substantial variation in operative volume, use of instrumented fusion, and postoperative outcomes. Among surgeons above the median operative volume, use of instrumented fusion ranged from 0% to >90% for scoliosis and 9% to 100% for spondylolisthesis, while rates of major in-hospital complications ranged from 0% to 25% for scoliosis and from 0% to 14% for spondylolisthesis. For scoliosis, orthopedic surgeons were more likely than neurosurgeons to perform instrumented fusion for scoliosis [49% vs. 33%, odds ratio (OR) = 2.3, 95% confidence interval (95% CI) 1.3-4.2, P-value = .006] as were fellowship-trained surgeons (49% vs. 25%, OR = 3.0, 95% CI 1.6-5.8; P = .001). Fellowship-trained surgeons had lower readmission rates. Surgeons with higher operative volumes used instrumented fusion more often (OR = 1.1, 95% CI 1.0-1.2, P < .05 for both diagnoses) and had lower rates of major in-hospital complications (OR = 0.91, 95% CI 0.85-0.97; P = .006). Surgical practice can vary greatly for degenerative spine conditions, even within the same region and among colleagues at the same institution. Surgical specialty and subspecialty, in addition to recent operative volume, can be linked to variations in spine surgeons' practice patterns and outcomes. These findings reinforce the notion that residency and fellowship training may contribute to variation and present important opportunities to optimize surgical practice over the course of surgeons' careers. Future efforts to reduce unexplained variation in surgical practice could test interventions focused on graduate medical education. Graphical Abstract.

Low-frequency Raman spectrum of 2D layered perovskites: Local atomistic motion or superlattice modes?

We report the low-frequency Raman spectrum (ω = 10 cm-1-150 cm-1) of a wide variety of alkylammonium iodide based 2D lead halide perovskites (2D LHPs) as a function of A-site cation (MA = methylammonium and FA = formamidinium), octahedral layer thickness (n = 2-4), organic spacer chain length (butyl-, pentyl-, hexyl-), and sample temperature (T = 77 K-293 K). Using density functional theory calculations under the harmonic approximation for n = 2 BA:MAPbI, we assign several longitudinal/transverse optical phonon modes between 30 cm-1 and 100 cm-1, the eigendisplacements of which are analogous to that observed previously for octahedral twists/distortions in bulk MAPbI. Additionally, we propose an alternative assignment for low-frequency modes below this band (<30 cm-1) as zone-folded longitudinal acoustic phonons corresponding to the periodicity of the entire layered structure. We compare measured spectra to predictions of the Rytov elastic continuum model for zone-folded dispersion in layered structures. Our results are consistent across the various 2D LHPs studied herein, with energetic shifts of optical phonons corresponding to microscopic structural differences between materials and energetic shifts of acoustic phonons according to changes in the periodicity and elastic properties of the perovskite/organic subphases. This study highlights the importance of both the local atomic order and the superlattice structure on the vibrational properties of layered 2D materials.

Recently reported familial hypercholesterolemia-related mutations from cases in the Middle East and North Africa region.

PURPOSE OF REVIEW: Familial hypercholesterolemia is an inherited disorder where cases have a significantly higher risk of having premature myocardial infarction than noncases. The prevalence of this genetic disease is currently unknown in countries of the Middle East and North Africa region. Given that a high percentage of marriages are consanguineous in this region, the prevalence may be much higher than assumed. We systematically reviewed the literature to identify case-related mutations reported within the last 4 years and since our first report in 2014. RECENT FINDINGS: Mutations were reported in familial hypercholesterolemia cases from the Saudi, Iranian, Lebanese, and Syrian populations. Some of the mutations were novel and a variety of familial hypercholesterolemia genotypes were identified, such as compound heterozygotes and double heterozygotes. SUMMARY: In recent years, work has been done to identify familial hypercholesterolemia cases in various countries of the Middle East and North Africa region. With regards to the prospective familial hypercholesterolemia registry for the Middle East and North Africa region, an important goal for the near future would be to have physician specialists collaborate with primary care clinicians for the identification and optimal care of familial hypercholesterolemia cases.

The Far Lateral Approach to the Craniovertebral Junction: An Update.

INTRODUCTION: Since 1972, when Hammon first described the far lateral approach (FLA) for treatment of vertebral artery aneurysms, it has undergone numerous modifications, including drilling of the occipital condyle, removal of the laminas of upper cervical vertebrae and so on. Also, the range of indications has increased exponentially. OBJECTIVE: In this paper we discuss state-of-the-art advances in the FLA, such as promising minimally invasive variants where an endoscope is used, and many others. METHODS: We reviewed all articles touching upon the FLA in the modern era (from the year 2000 onward) and selected those that presented a significant contribution to the development of the relevant approach. The database used was PubMed. RESULTS AND CONCLUSION: We found several new caveats not mentioned in other reviews or book chapters. The FLA is an ever-changing field of battle where the common and ultimate goals are to minimize the risk of injuring the major vessel in the region-the vertebral artery-and to provide such an angle of attack upon the tumours in the anterior and anterolateral foramen magnum that it is feasible to ensure gross total resection. This paper is an update on the knowledge about this approach, which we feel is necessary.

Extreme Lateral Approach to the Craniovertebral Junction: An Update.

INTRODUCTION: The term 'extreme lateral approach' (ELA) was first introduced by Sen and Sekhar relatively recently (in 1990). Its definition varies and remains controversial, but it generally entails more aggressive bony removal than the far lateral approach (FLA). GOAL: In this paper we review the relevant literature and weigh up the advantages and disadvantages of this approach. We propose methods to manage the complications resulting from the more invasive character of the ELA. Some modern trends regarding how to definitely distinguish the ELA from the FLA are also presented. METHODS: Using the PubMed database, literature was collected on the relevant topics and subsequently reviewed. All up-to-date tips and tricks were carefully gathered, and current morbidity and mortality rates were obtained, as well as further perspectives. RESULTS AND CONCLUSION: The morbidity associated with the ELA remains higher than that associated with the FLA, but the mortality nowadays is comparable. The ELA undoubtedly is a challenging procedure requiring deep insight into the relevant anatomy and its normal variants.

The High Cervical Anterolateral Retropharyngeal Approach.

The first high cervical anterolateral retropharyngeal (HCALR) approach was reported by Stevenson et al. for a clivus chordoma in 1966. Anterior approaches to the spine have often been developed in response to problems presented by tuberculous spondylitis. This approach is indicated in anterior high cervical spine cases such as tumour resection, abscess drainage, atlantoaxial subluxation; decompression and stabilization. To our knowledge, only 21 papers in the literature have mentioned this approach. Its main advantage over posterior approaches is easy positioning and minimal need for soft tissue dissection. The HCALR approach provides wide exposure (of the anterior upper cervical spine, lower clivus and brainstem region) and feasibility for instrumentation. The limited space in which important neurovascular and visceral structures course and overlap contributes to the complexity of the anatomy. Navigating this intricate anatomy is essential for the safety of this approach and has been a drawback for utilization of the retropharyngeal corridor. This approach is one of the safest and most effective methods available to access the craniocervical junction. The benefits clearly outweigh the risks and complications.

Insights into the Past and Future of Atlantoaxial Stabilization Techniques.

Over the past century, atlantoaxial stabilization techniques have improved considerably. To our knowledge there has been a scarcity of articles published that focus specifically on the history of atlantoaxial stabilization. Examining the history of instrumentation allows us to evaluate the impact of early influences on current modern stabilization techniques. It also provides inspiration to further develop the techniques and prevents repetition of mistakes. This paper reviews the evolution of C1-C2 instrumentation techniques over time and provides insights into the future of these practices.We did an extensive literature search in PubMed, Embase and Google Scholar, using the following search terms: 'medical history', 'atlantoaxial', 'C1/C2', 'stabilization', 'instrumentation', 'fusion', 'arthrodesis', 'grafting', 'neuroimaging', 'biomechanical testing', 'anatomical considerations' and 'future'.Many different entry zones have been tested, as well as different constructs, from initial attempts with use of silk threads to use of hooks and rod-wire techniques, and handling of bone grafts, which eventually led to the development of the advanced screw-rod constructs that are currently in use. Much of this evolution is attributable to advancements in neuroimaging, a wide range of new materials available and an improvement in biomechanical understanding in relation to anatomical structures.

Occipitocervical Fusion: An Updated Review.

Occipitocervical fusion (OCF) is indicated for instability at the craniocervical junction (CCJ). Numerous surgical techniques, which evolved over 90 years, as well as unique anatomic and kinematic relationships of this region present a challenge to the neurosurgeon. The current standard involves internal rigid fixation by polyaxial screws in cervical spine, contoured rods and occipital plate. Such approach precludes the need of postoperative external stabilization, lesser number of involved spinal segments, and provides 95-100% fusion rates. New surgical techniques such as occipital condyle screw or transarticular occipito-condylar screws address limitations of occipital fixation such as variable lateral occipital bone thickness and dural sinus anatomy. As the C0-C1-C2 complex is the most mobile portion of the cervical spine (40% of flexion-extension, 60% of rotation and 10% of lateral bending) stabilization leads to substantial reduction of neck movements. Preoperative assessment of vertebral artery anatomical variations and feasibility of screw insertion as well as visualization with intraoperative fluoroscopy are necessary. Placement of structural and supplemental bone graft around the decorticated bony elements is an essential step of every OCF procedure as the ultimate goal of stabilization with implants is to provide immobilization until bony fusion can develop.

In cancer, A-to-I RNA editing can be the driver, the passenger, or the mechanic.

In recent years, A-to-I RNA modifications performed by the Adenosine Deaminase Acting on RNA (ADAR) protein family were found to be expressed at altered levels in multiple human malignancies. A-to-I RNA editing changes adenosine to inosine on double stranded RNA, thereby changing transcript sequence and structure. Although A-to-I RNA editing have the potential to change essential mRNA transcripts, affecting their corresponding protein structures, most of the human editing sites identified to date reside in non-coding repetitive transcripts such as Alu elements. Therefore, the impact of the hypo- or hyper-editing found in specific cancers remains unknown. Moreover, it is yet unclear whether or not changes in RNA editing and ADAR expression levels facilitate or even drive cancer progression or are just a byproduct of other affected pathways. In both cases, however, the levels of RNA editing and ADAR enzymes can possibly be used as specific biomarkers, as their levels change differently in specific malignancies. More significantly, recent studies suggest that ADAR enzymes can be used to reverse the oncogenic process, suggesting a potential for gene therapies. This review focuses on new findings that suggest that RNA editing by ADARs can affect cancer progression and even formation. We also discuss new possibilities of using ADAR enzymes and RNA editing as cancer biomarkers, indicators of chemotherapeutic drug sensitivity, and even to be themselves potential therapeutic tools.

A-to-I RNA editing - thinking beyond the single nucleotide.

Adenosine-to-inosine RNA editing is a conserved process, which is performed by ADAR enzymes. By changing nucleotides in coding regions of genes and altering codons, ADARs expand the cell's protein repertoire. This function of the ADAR enzymes is essential for human brain development. However, most of the known editing sites are in non-coding repetitive regions in the transcriptome and the purpose of editing in these regions is unclear. Recent studies, which have shown that editing levels of transcripts vary between tissues and developmental stages in many organisms, suggest that the targeted RNA and ADAR editing are both regulated. We discuss the implications of these findings, and the possible role of RNA editing in innate immunity.

Microendoscopic Tailored Spine Decompression as a Less-Invasive, Stability-Preserving Surgical Option to Instrumented Correction in Complex Spine Deformities: A Preliminary Multicenter Experience.

OBJECTIVES: The aim of this study was to explore the effectiveness of a less-invasive posterior spine decompression in complex deformities. We studied the potential advantages of the microendoscopic approach, supplemented by the piezoelectric technique, to decompress both sides of the vertebral canal from a one-sided approach to preserve spine stability, ensuring adequate neural decompression. METHODS: A series of 32 patients who underwent a tailored stability-preserving microendoscopic decompression for lumbar spine degenerative disease was retrospectively analyzed. The patients underwent selective bilateral decompression via a monolateral approach, without the skeletonization of the opposite side. For omo- and the contralateral decompression, we used a microscopic endoscopy-assisted approach, with the assistance of piezosurgery, to work safely near the exposed dura mater. Piezoelectric osteotomy is extremely effective in bone removal while sparing soft tissues. RESULTS: In all patients, adequate decompression was achieved with a high rate of spine stability preservation. The approach was essential in minimizing the opening, therefore reducing the risk of spine instability. Piezoelectric osteotomy was useful to safely perform the undercutting of the base of the spinous process for better contralateral vision and decompression without damaging the exposed dura. In all patients, a various degree of neurologic improvement was observed, with no immediate spine decompensation. CONCLUSIONS: In selected cases, the tailored microendoscopic monolateral approach for bilateral spine decompression with the assistance of piezosurgery is adequate and safe and shows excellent results in terms of spine decompression and stability preservation.

A prospective pilot study of gut microbiome in cerebral vasospasm and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

A recent systematic review indicated that gut-microbiota-brain axis contributes to growth and rupture of intracranial aneurysms. However, gaps were detected in the role of intestinal microbiome in cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (aSAH). This is the first pilot study aiming to test study feasibility and identify differences in gut microbiota between subjects with and without CVS following aSAH. A prospective nested case-control pilot study with 1:1 matching was conducted recruiting subjects with aSAH: cases with CVS; and controls without CVS based on the clinical picture and structured bedside transcranial Doppler (TCD). Fecal samples for microbiota analyses by means of 16S rRNA gene amplicon sequencing were collected within the first 96 h after ictus. Operational taxonomic unit tables were constructed, diversity metrics calculated, phylogenetic trees built, and differential abundance analysis (DAA) performed. At baseline, the groups did not differ significantly in basic demographic and aneurysm-related characteristics (p > 0.05). Alpha-diversity (richness and Shannon Index) was significantly reduced in cases of middle cerebral artery (MCA) vasospasm (p < 0.05). In DAA, relative abundance of genus Acidaminococcus was associated with MCA vasospasm (p = 0.00013). Two butyrate-producing genera, Intestinimonas and Butyricimonas, as well as [Clostridium] innocuum group had the strongest negative correlation with the mean blood flow velocity in anterior cerebral arteries (p < 0.01; rho = - 0.63; - 0.57, and - 0.57, respectively). In total, 16 gut microbial genera were identified to correlate with TCD parameters, and two intestinal genera correlated with outcome upon discharge. In this pilot study, we prove study feasibility and present the first preliminary evidence of gut microbiome signature associating with CVS as a significant cause of stroke in subjects with aSAH.

Role of endoscopy in primary sclerosing cholangitis.

Primary sclerosing cholangitis is a chronic cholestatic liver disease characterized by progressive inflammation affecting the entire biliary tree and leading to biliary symptoms and complications. It is of unclear etiology and is usually associated with inflammatory bowel diseases. Despite advances in modern medicine, treatment options remain very limited, and without liver transplantation, survival rates are reduced. We aim in this review to highlight available endoscopic methods to evaluate, diagnose, and manage symptoms and complications associated with this disease, including diagnosis of cholangiocarcinoma and endoscopic palliative treatment for advanced cholangiocarcinoma not amenable to surgical resection.

Association between intrauterine fetal growth restriction and ABO blood groups at King Abdulaziz University Hospital, Saudi Arabia: Retrospective study.

OBJECTIVES: To investigate the potential association between ABO blood groups and intrauterine fetal growth restriction (IUGR) among pregnant women who delivered at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. METHODS: This is a retrospective cohort study analyzed the medical records of pregnant women who delivered at KAUH and had postnatal follow-up visits. Missing data were completed by conducting phone interviews with patients. RESULTS: A total of 436 patients with a mean age of 31.2±5.5 years were included in the study. 50.7% of the women had blood type O, 28.4% had blood type A, 16.5% had blood type B, and 4.4% had blood type AB. The majority (94.7%) tested positive for the Rhesus antigen. Although statistically significant, women with blood groups AB and B exhibited higher rates of IUGR (31.6%, and 27.8%, respectively) compared to those with blood groups A and O, who had lower rates of IUGR (26.6%, and 24%, respectively). CONCLUSION: Our study results showed that women with blood groups AB and B had slightly higher rates of IUGR than those with A and O, who had lower rates of IUGR. A larger study comparing blood group O to other groups may provide more insight into the relationship between ABO blood groups and IUGR.

Discovery of enhanced lattice dynamics in a single-layered hybrid perovskite.

Layered hybrid perovskites exhibit emergent physical properties and exceptional functional performances, but the coexistence of lattice order and structural disorder severely hinders our understanding of these materials. One unsolved problem regards how the lattice dynamics are affected by the dimensional engineering of the inorganic frameworks and their interaction with the molecular moieties. Here, we address this question by using a combination of spontaneous Raman scattering, terahertz spectroscopy, and molecular dynamics simulations. This approach reveals the structural dynamics in and out of equilibrium and provides unexpected observables that differentiate single- and double-layered perovskites. While no distinct vibrational coherence is observed in double-layered perovskites, an off-resonant terahertz pulse can drive a long-lived coherent phonon mode in the single-layered system. This difference highlights the dramatic change in the lattice environment as the dimension is reduced, and the findings pave the way for ultrafast structural engineering and high-speed optical modulators based on layered perovskites.

Nonsurgical treatment reduces tendon inflammation and elevates tendon markers in early healing.

Operative treatment is assumed to provide superior outcomes to nonoperative (conservative) treatment following Achilles tendon rupture, however, this remains controversial. This study explores the effect of surgical repair on Achilles tendon healing. Rat Achilles tendons (n = 101) were bluntly transected and were randomized into groups receiving repair or non-repair treatments. By 1 week after injury, repaired tendons had inferior mechanical properties, which continued to 3- and 6-week post-injury, evidenced by decreased dynamic modulus and failure stress. Transcriptomics analysis revealed >7000 differentially expressed genes between repaired and non-repaired tendons after 1-week post-injury. While repaired tendons showed enriched inflammatory gene signatures, non-repaired tendons showed increased tenogenic, myogenic, and mechanosensitive gene signatures, with >200-fold enrichment in Tnmd expression. Analysis of gastrocnemius muscle revealed elevated MMP activity in tendons receiving repair treatment, despite no differences in muscle fiber morphology. Transcriptional regulation analysis highlighted that the highest expressed transcription factors in repaired tendons were associated with inflammation (Nfκb, SpI1, RelA, and Stat1), whereas non-repaired tendons expressed markers associated with tissue development and mechano-activation (Smarca1, Bnc2, Znf521, Fbn1, and Gli3). Taken together, these data highlight distinct differences in healing mechanism occurring immediately following injury and provide insights for new therapies to further augment tendons receiving repaired and non-repaired treatments.

Practice of Placenta Submission for Histopathological Examination, Experience of a Teaching/Tertiary Care Hospital in Saudi Arabia.

Objectives The aim of this study is to determine the appropriateness of histopathologic examination of the placenta at King Abdulaziz University Hospital (KAUH), Jeddah, based on the guidelines of the College of American Pathologists (CAP). Methods It is a retrospective review of obstetric and pathologic records for all deliveries at KAUH, between January 1, 2017, and April 30, 2019. The placentae were assessed for eligibility to undergo pathologic examination. Furthermore, examined and non-examined placentae meeting the CAP criteria were compared based on their actual indications. Results There were 8,929 deliveries, of which 1,444 (16.2%) placentae met the CAP guidelines. A total of 583/1,444 placentae (40.4%; 95% confidence interval [CI] = 37.8-43) were sent for pathologic examination. Of the 7,485 placentae that did not require submission for pathological examination, as determined by the pathologist, 7,456 (99.6%; 95% CI = 99.4-99.7) were not submitted appropriately. The labor and delivery staff were more likely to submit placentae with fetal/neonatal indications rather than those with maternal indications for examination, which was statistically significant (odds ratio = 6.5; 95% CI = 5.08-8.30). Conclusion While most of the examined placentae at KAUH met the CAP guidelines, there was a substantial under-submission of eligible placentae. Further studies are advised to reveal the reasons behind this underestimation so that correctional measures may be adopted, as placenta examination is a valuable tool to understand the risk factors and pathogenesis of deleterious maternal, neonatal, and fetal events.

Does the Symmetry of Patellar Morphology Matter When Matching Osteochondral Allografts for Osteochondral Defects Involving the Central Ridge of the Patella?

OBJECTIVE: The purpose of this study was to determine if differences in Wiberg classification play a role in the ability of donor patellar osteochondral allografts to match the native patellar surface when treating osteochondral defects of the patellar apex. DESIGN: Twenty (10 Wiberg I and 10 Wiberg II/III) human patellae were designated as the recipient. Each recipient was size-matched to both a Wiberg I and a Wiberg II/III patellar donor. A 16-mm circular osteochondral "defect" was created on the central ridge of the recipient patella. The randomly ordered donor Wiberg I or Wiberg II/III plug was harvested from a homologous location and transplanted into the recipient. The recipient was then nano-CT (computed tomography) scanned, digitally reconstructed, registered to the initial nano-CT scan of the recipient patella, and processed to determine root mean squared circumferential step-off heights as well as surface height deviation. The process was then repeated for the other allograft plug. RESULTS: There was no significant difference in mean step-off height between matched and unmatched Wiberg plugs; however, there was a statistically significant difference in surface height deviation over the whole surface (0.50 mm and 0.64 mm respectively, P = 0.03). This difference of 0.14 mm is not felt to be clinically significant. Tibial width was correlated to patellar width (r = 0.82) and patellar height (r = 0.68). CONCLUSIONS: For osteochondral allograft sizes up to 16 mm there appears to be no advantage to match donor and recipient patellar morphology. Further study is warranted to evaluate defects requiring larger graft sizes.

Two Origins of Broadband Emission in Multilayered 2D Lead Iodide Perovskites.

Broadband emission in lead iodide 2D perovskites has been alternately attributed to self-trapped excitons (STEs) or permanent structural defects and/or impurities. Here, we investigate six different multilayered (n > 1) 2D lead iodide perovskites as a function of sample temperature from 5 to 300 K. We distinguish shallow defect-associated emission from a broad near-infrared (NIR) spectral feature, which we assign to an STE through subgap photoexcitation experiments. When we varied the thickness (n = 2, 3, 4), A-site cation (methylammonium vs formamidinium), and organic spacer (butylammonium vs hexylammonium vs phenylethylammonium), we found that the temperature dependence of broad NIR emission was strongly correlated with both the strength of electron-phonon coupling and the extent of structural deformation of the ground-state lattice, strongly supporting the assignment of this spectral feature to an STE. However, the extent to which formation of these STEs is intrinsic versus defect-assisted remains open to debate.