Complex Cases Research Articles

Bone remodeling after revision total hip arthroplasty for large acetabular defects.

Large acetabular bone defects are challenging in hip revision surgery. Clinical assessment is crucial to evaluate modern technologies in surgical reconstruction. We aimed to better understand the bone remodeling that occurs following acetabular reconstruction. Our objectives were: (1) To characterize changes in the shape of the pelvis by studying sequential computed tomography (CT) scans collected immediately and 1-year postoperatively and (2) to identify which part of the pelvis is most susceptible to remodeling. We used the CT scans taken at two timepoints, of 24 patients with acetabular bone defects classified as Paprosky IIIB, treated with three-dimensional (3D)-printed custom-made acetabular implants. Segmented 3D models of the bony pelvis were co-registered using three different techniques. A global co-registration of the full pelvis was conducted, followed by the co-registration of the innominate bone and then ilium only, on the ipsilateral reconstructed side. The relative movements of the ilium, ischium, and pubis were analyzed from visual inspection and using co-registration metrics (root mean square error and intersection over union). No bone remodeling was found in 14/24 patients (58%). The co-registration of the innominate bone indicated bone remodeling in five cases (21%), while the remaining five cases (21%) presented remodeling in the global co-registration but not the innominate bone co-registration, suggestive of changes occurring at the sacroiliac joint. Changes in the pelvic shape were greatest at the pubis and ischium. Bone remodeling may occur in complex cases of Paprosky type IIIB defects, after acetabular reconstruction (occurrence of 21%, 5/24 cases). Surgeons and engineers should consider this when monitoring implant migration.

The Current State of Coronary Revascularization: Coronary Artery Bypass Graft Surgery Versus Percutaneous Coronary Interventions.

The optimal revascularization strategy for coronary artery disease depends on various factors, such as disease complexity, patient characteristics, and preferences. Including a heart team in complex cases is crucial to ensure optimal outcomes. Decision-making between percutaneous coronary intervention and coronary artery bypass grafting must consider each patient's clinical profile and coronary anatomy. While current practice guidelines offer some insight into the optimal revascularization approach for the various phenotypes of coronary artery disease, the evidence to support either strategy continues to evolve and grow. Given the large amount of contemporary data on revascularization, this review aims to comprehensively summarize the literature on coronary artery bypass grafting and percutaneous coronary intervention in patients across the spectrum of coronary artery disease phenotypes. Contemporary evidence suggests that for patients with triple vessel disease, coronary artery bypass grafting is preferred over percutaneous coronary intervention due to better long-term outcomes, including lower rates of death, myocardial infarction, and target vessel revascularization. Similarly, for patients with left main coronary artery disease, both percutaneous coronary intervention and coronary artery bypass grafting can be considered, as they have shown similar efficacy in terms of major adverse cardiac events, but there may be a slightly higher risk of death with percutaneous coronary intervention. For proximal left anterior descending artery disease, both percutaneous coronary intervention and coronary artery bypass grafting are viable options, but coronary artery bypass grafting has shown lower rates of repeat revascularization and better relief from angina. The Synergy Between PCI with Taxus and Cardiac Surgery score can help in decision-making by predicting the risk of adverse events and guiding the choice between percutaneous coronary intervention and coronary artery bypass grafting. European and American guidelines both agree with including a heart team that can develop and lay out individualized, optimal treatment options with respect for patient preferences. The debate between coronary artery bypass grafting versus percutaneous coronary intervention in multiple different scenarios will continue to develop as technology and techniques improve for both procedures. Risk factors, pre, peri, and post-procedural complications involved in both revascularization strategies will continue to be mitigated to optimize outcomes for those patients for which coronary artery bypass grafting or percutaneous coronary intervention provide ultimate benefit. Methods to avoid unnecessary revascularization continue to develop as well as percutaneous technology that may allow patients to avoid surgical intervention when possible. With such changes, revascularization guidelines for specific patient populations may change in the coming years, which can serve as a limitation of this time-dated review.

Designing an Intelligent Contract with Communications and Risk Data

Contract automation is a challenging topic within Artificial Intelligence and LegalTech. From digitised contracts via smart contracts, we are heading towards Intelligent Contracts (iContracts). We will address the main challenge of iContracts: the handling of communications and risk data in contract automation. Our Research Question reads: to what extent is it possible to develop an ontology that automates contracts with communications and risk data? The article designs and conceptualises an iContract ontology. Our findings validate the conceptual expressiveness of our ontology. A brief discussion highlights the value of the ontology design and its application domains. From the results, we may conclude that the current method is innovative and that further research is necessary for handling more complex use cases.

Utilizing ChatGPT for Curriculum Learning in Developing a Clinical Grade Pneumothorax Detection Model: A Multisite Validation Study.

Background: Pneumothorax detection is often challenging, particularly when radiographic features are subtle. This study introduces a deep learning model that integrates curriculum learning and ChatGPT to enhance the detection of pneumothorax in chest X-rays. Methods: The model training began with large, easily detectable pneumothoraces, gradually incorporating smaller, more complex cases to prevent performance plateauing. The training dataset comprised 6445 anonymized radiographs, validated across multiple sites, and further tested for generalizability in diverse clinical subgroups. Performance metrics were analyzed using descriptive statistics. Results: The model achieved a sensitivity of 0.97 and a specificity of 0.97, with an area under the curve (AUC) of 0.98, demonstrating a performance comparable to that of many FDA-approved devices. Conclusions: This study suggests that a structured approach to training deep learning models, through curriculum learning and enhanced data extraction via natural language processing, can facilitate and improve the training of AI models for pneumothorax detection.

Wartime penetrating skull base trauma with unpredictable internal fragment ricochet and migration: illustrative case.

Transnasal transsphenoidal penetrating craniocerebral injury is very rare even in wartime. Cases with good outcomes are even less common. A 20-year-old male sustained multiple fragment wounds to his head and face from a landmine explosion. One metal fragment entered his right nostril, traversed the nasal septum and anterior sphenoid sinus, and ricocheted superiorly off the clivus. The fragment then traveled almost to the surface of the left parietal lobe. Subsequently, under its own weight, it migrated back down its original track. The patient suffered cerebrospinal fluid rhinorrhea, pneumocephalus, and right-sided hemiparesis. Digital subtraction angiography was followed by microscopic transnasal skull base reconstruction supplemented by external lumbar drainage. Follow-up brain computed tomogrpahy showed further metallic fragment migration through the ventricular system. The fragment was removed through a transcortical approach. The patient's neurological examination and brain magnetic resonance imaging results demonstrated good recovery. The absence of external signs of deep injuries does not exclude the presence of a penetrating craniocerebral injury. Metal fragments may undergo ricochet and internal migration in both the brain parenchyma and the ventricular system. Timely diagnosis including three-dimensional reconstruction of a projectile's trajectory may facilitate appropriate surgical planning in complex cases. Intraventricular fragment migration may necessitate microsurgical removal. https://thejns.org/doi/10.3171/CASE24128.

Effect of different optimization parameters in single isocenter multiple brain metastases radiosurgery

PurposeAutomated treatment planning for multiple brain metastases differs from traditional planning approaches. It is therefore helpful to understand which parameters for optimization are available and how they affect the plan quality. This study aims to provide a reference for designing multi-metastases treatment plans and to define quality endpoints for benchmarking the technique from a scientific perspective.MethodsIn all, 20 patients with a total of 183 lesions were retrospectively planned according to four optimization scenarios. Plan quality was evaluated using common plan quality parameters such as conformity index, gradient index and dose to normal tissue. Therefore, different scenarios with combinations of optimization parameters were evaluated, while taking into account dependence on the number of treated lesions as well as influence of different beams.ResultsDifferent scenarios resulted in minor differences in plan quality. With increasing number of lesions, the number of monitor units increased, so did the dose to healthy tissue and the number of interlesional dose bridging in adjacent metastases. Highly modulated cases resulted in 4–10% higher V10% compared to less complex cases, while monitor units did not increase. Changing the energy to a flattening filter free (FFF) beam resulted in lower local V12Gy (whole brain-PTV) and even though the number of monitor units increased by 13–15%, on average 46% shorter treatment times were achieved.ConclusionAlthough no clinically relevant differences in parameters where found, we identified some variation in the dose distributions of the different scenarios. Less complex scenarios generated visually more dose overlap; therefore, a more complex scenario may be preferred although differences in the quality metrics appear minor.

Altered Inflammatory State and Mitochondrial Function Identified by Transcriptomics in Paediatric Congenital Heart Patients Prior to Surgical Repair.

Congenital heart disease (CHD) remains the most common birth defect, with surgical intervention required in complex cases. Right ventricle (RV) function is known to be a major predictor of sustained cardiac health in these patients; thus, by elucidating the divergent profiles between CHD and the control through tissue analysis, this study aims to identify new avenues of investigation into the mechanisms surrounding reduced RV function. Transcriptomic profiling, in-silico deconvolution and functional network analysis were conducted on RV biopsies, identifying an increase in the mitochondrial dysfunction genes RPPH1 and RMPR (padj = 4.67 × 10-132, 2.23 × 10-107), the cytotoxic T-cell markers CD8a, LAGE3 and CD49a (p = 0.0006, p < 0.0001, and p = 0.0118) and proinflammatory caspase-1 (p = 0.0055) in CHD. Gene-set enrichment identified mitochondrial dysfunctional pathways, predominately changes within oxidative phosphorylation processes. The negative regulation of mitochondrial functions and metabolism was identified in the network analysis, with dysregulation of the mitochondrial complex formation. A histological analysis confirmed an increase in cellular bodies in the CHD RV tissue and positive staining for both CD45 and CD8, which was absent in the control. The deconvolution of bulk RNAseq data suggests a reduction in CD4+ T cells (p = 0.0067) and an increase in CD8+ T cells (p = 0.0223). The network analysis identified positive regulation of the immune system and cytokine signalling clusters in the inflammation functional network, as there were lymphocyte activation and leukocyte differentiation. Utilising RV tissue from paediatric patients undergoing CHD cardiac surgery, this study identifies dysfunctional mitochondrial pathways and an increase in inflammatory T-cell presence prior to reparative surgery.

Fistuloclysis in the nutritional management of a enteroatmospheric fistula: case report and literature review

Introduction: The open abdomen (OA) strategy has been widely adopted as a life-saving intervention in critically ill patients. Initially described as part of the damage control surgery in trauma practice, OA techniques have since further expanded its indications, being successfully adapted to many non-trauma emergent surgical conditions, including abdominal compartment syndrome, severe acute pancreatitis, vascular diseases, and peritonitis/intra-abdominal sepsis. Case Report: This report presents a successful application of this technique in the management of a high-output enteroatmospheric fistula following abdominal complications in a trauma patient. Final considerations: Fistuloclysis is a promising modality for the nutritional support of complex cases of enteroatmospheric fistula in OA patients that also align with the recent efforts to ensure enteral nutrition whenever feasible. Besides its advantages over prolonged exclusive parenteral nutrition in terms of morbidity and costs, the improvement in bowel mucosal trophism is critical for the definitive reconstructive surgery. Future clinical guidelines may encourage the use of fistuloclysis as a safe and effective alternative method for the management of these challenging cases.

Lutetium-177-Prostate-Specific Membrane Antigen Radioligand Therapy: What Is the Value of Post-Therapeutic Imaging?

Lutetium-177 (Lu-177)-labelled radioligand therapies (RLT) targeting prostate-specific membrane antigen (PSMA) present a promising treatment for patients with progressive metastasized castration-resistant prostate cancer (mCRPC). Personalized dosimetry, facilitated by post-therapeutic imaging, offers the potential to enhance treatment efficacy by customizing radiation doses to individual patient needs, thereby maximizing therapeutic benefits while minimizing toxicity to healthy tissues. However, implementing personalized dosimetry is resource-intensive, requiring multiple single-photon emission-computed tomography (SPECT)/CT scans and posing significant logistical challenges for both healthcare facilities and patients. Despite these challenges, personalized dosimetry can lead to optimized radiation delivery, improved safety, and better management of complex cases. Nevertheless, the financial and resource burdens complicate its adoption in routine clinical practice. While the European Association of Nuclear Medicine (EANM) supports personalized dosimetry, standardization is lacking due to these practical constraints. Further research and streamlined methodologies are essential to balance the benefits and feasibility of personalized dosimetry, potentially improving treatment outcomes for mCRPC patients.

Urgent Transurethral Resection of a Massive Bladder Clot in a Hemodynamically Unstable Patient

This case report describes a 58-year-old male with a history of chronic smoking who presented with severe hematuria and hemodynamic instability. Initial assessment revealed a massive bladder clot and critically low hemoglobin. Despite initial interventions, the patient suffered cardiac arrest requiring prolonged resuscitation. Emergency cystoscopy was performed, removing a 320-gram clot and resecting a 2 cm bladder tumor. Despite successful surgical intervention and post-operative intensive care, the patient succumbed to multi-organ failure six days later. This case highlights the potential severity of hematuria and the importance of prompt diagnosis and treatment of underlying causes. It also demonstrates the challenges in managing complex cases involving massive hemorrhage, hemodynamic instability, and the sequelae of prolonged cardiac arrest.

Fetal Alcohol Syndrome: a complex case of teratogenic effects of maternal alcohol consumption and clinical managment

Fetal Alcohol Syndrome: a complex case of teratogenic effects of maternal alcohol consumption and clinical managment

INSTALLATIONS OF THE JUDICIAL SETUP IN THE NEWLY MERGED AREAS OF ERSTWHILE FATA: THE FUTURE OF JIRGA

The Pashtun Jirga, a traditional dispute resolution system, has historically played a crucial role in promoting peace and resolving conflicts within Pashtun communities. However, the recent installation of a formal judicial system in the merged areas of the former Federally Administered Tribal Areas (FATA) in Pakistan raises questions about the future of the Jirga. This study examines the significance of the Jirga in Pashtun society and analyses the potential impact of the new judicial system on its continued existence. The research concludes that the formal system has had minimal influence on the prevalence of the Jirga primarily due to two factors: The local population is accustomed to and trusts the traditional Jirga system. Certain complex cases in the region prove challenging for the formal system to handle effectively, necessitating the assistance of the Jirga. Based on these findings, the study recommends the coexistence of both the Jirga and the judicial system. This approach would enable the region to benefit from the strengths of both traditional and formal systems, ultimately contributing to lasting peace and security.

Parotid Gland Tumors: Molecular Diagnostic Approaches.

Parotid gland pathology represents a web of differential diagnoses. There are many complex cases that require extensive diagnostic tests for a complete and correct final pathology diagnosis. Currently the official classification of parotid gland tumors extends over more than 40 subtypes. We performed a query of the PubMed database regarding the use of molecular biology tests in performing a better characterization of the tumors in specific cases. By using fluorescence in situ hybridization (FISH), reverse transcription polymerase chain reaction (RT-PCR) or next-generation sequencing, the team managing complex cases can offer a personalized therapeutic solution. We review the molecular differential diagnosis according to published articles in the last 5 years for many types of parotid gland tumors ranging from benign to borderline malign tumors to malign aggressive tumors. Mucoepidermoid carcinoma is a distinct subtype of parotid malignancy that was the subject of a consistent number of articles. However, the molecular biology diagnosis techniques helped more in excluding the diagnosis of mucoepidermoid carcinoma, and probably retrospectively limiting the number of cases with this final diagnosis. In Romania, the molecular biology diagnosis is available only in limited research facilities and should receive more consistent funding that will make it available on a larger scale. The novelty of this scoping review is that we propose an algorithm for molecular differential diagnosis of the tumors that could be encountered in the parotid gland.

Robotic pyelolithotomy for the treatment of large renal stones: a single-center experience over seven years.

Urolithiasis prevalence varies globally between 1-20%, influenced by regional factors. Robotic pyelolithotomy (RPL) presents an interesting alternative to PCNL, considered the gold standard for symptomatic stones smaller than 20 mm, as it carries a risk of significant complications. However, studies on RPL are limited, especially in anatomically complex cases, where RPL proves to be particularly useful. The study aims to update and review outcomes of RPL in a high-volume robotic center. A retrospective analysis of 153 patients treated with RPL for staghorn kidney stones at a single center from February 2016 to December 2023 was conducted. Data including demographics, preoperative renal function, stone characteristics, operative and postoperative outcomes, and costs were collected. Stone-free rates (SFR) and complications were assessed at follow-up intervals up to 12 months post-surgery. The study showed an initial 3-month stone-free rate (SFR) of 93.5%, which decreased to 83.5% at 12-months. This trend may reflect new stone formation rather than procedure failure. Sub-analysis revealed a significant difference in SFR between patients with pelvic and pyelocalyceal stones at each follow-up. Multivariate regression analysis identified in the pyelocalyceal group that higher BMI and larger stones were associated with higher failure rates at both 6 and 12 months. RPL is a safe and effective treatment for large renal stones, offering a high SFR and low complication rate. It is particularly beneficial in cases with complex anatomy or requiring concurrent renal procedures. However, patient selection is crucial, considering factors like stone location and size. Further research is needed to compare RPL with other treatment methods.

O-270 Clinical-grade whole genome sequencing-based haplarithmisis enables all forms of preimplantation genetic testing

Abstract Study question Can a simple, and scalable assay be developed to concurrently perform all forms of preimplantation genetic testing (PGT), effectively addressing the increasing demand? Summary answer Whole genome sequencing-based haplarithmisis offers a single-assay solution for all forms of PGT, enhancing resolution and diagnosis in complex cases. What is known already State-of-the-art preimplantation genetic testing (PGT) methods, including genotyping-by-sequencing (GBS)-based haplotyping, enable PGT for monogenic disorders (PGT-M), structural rearrangements (PGT-SR), and aneuploidies (PGT-A) in a single assay. However, they are labour intensive, only partially cover the genome, require a close relative to determine meiotic and mitotic origin of aneuploidies, and are troublesome for consanguineous families and in complex genomic contexts. Furthermore, the prevailing PGT approach for mitochondrial DNA disorders (PGT-MT) involves a PCR-based method. This underscores the need to develop a universal PGT method that streamlines laboratory protocols and provides genome-wide coverage to address genetic disorders, even in complex genomic loci. Study design, size, duration In a retrospective pilot study, we compared whole genome sequencing (WGS) at 30-40X with GBS (6 embryos, 2 families, 3 indications). We carried out subsampling of WGS data and determined 10X as the optimal diagnostic depth-of-coverage. We clinically validated our approach by comparing WGS to GBS for PGT-M and PGT-SR (31 embryos, 16 families, 22 indications), to shallow sequencing for PGT-SR (10 embryos, 3 families) and to PCR-based PGT for PGT-MT (10 embryos, 2 families). Participants/materials, setting, methods DNA from parents and close relative(s) and whole genome amplified (WGAed) DNA from embryos, underwent WGS with subsequent haplarithmisis. Quality metrics, such as Mendelian inconsistency rates, number of informative SNPs, and haplotype concordance were assessed. Translocation breakpoints were identified utilizing aberrantly aligned paired sequencing reads. Additionally, single-nucleotide variants (SNVs), including mitochondrial DNA SNVs, were detected by allele counting. Finally, segregational origin was determined via a parents-only haplarithmisis approach that uses the embryo as phasing reference. Main results and the role of chance WGS-PGT alleviates technical limitations by decreasing WGA artifacts by 68.4%, increasing breadth of coverage by 4-fold, and decreasing wet-lab turnaround time by 2.5-fold. Owing to its inherent higher resolution and improved genomic coverage, 5 out of 13 – previously inconclusive – embryos with genetic disorders in complex genomic regions could be assigned a diagnosis. Furthermore, we show the ability to directly detect single- and few-base pair genetic variants in any region of interest. Importantly, we show trio-based PGT-A for aneuploidy origin, an approach we term PGT-AO that – using the parents-only genotype calls – can detect the segregational origin of aneuploidies without the need of a close relative as reference for phasing. The segregational origin detected by parents-only haplarithmisis was concordant with the segregational origin determined from haplarithmisis when using a close relative. Unbalanced translocations could be detected indirectly via haplotyping or directly at single base resolution using a structural variant caller. Mitochondrial heteroplasmy level calculation from WGS yielded comparable results to PCR-based methods, both in blastomere and trophectoderm biopsy samples. Limitations, reasons for caution Direct variant detection with an average coverage of 10X may occasionally be inadequate, as certain locations may lack sufficient coverage (&amp;lt;5 reads). Inherently to the limited sample size of PGT-MT families, WGS-PGT needs further validation. The need for invasive trophectoderm biopsies of preimplantation embryos remains the key limitation of WGS-PGT. Wider implications of the findings Our approach enables all forms of PGT in a single assay. Direct variant detection complements haplarithmisis, addressing inconclusive findings and aiding families with a de novo variant or lacking a close relative for phasing. Finally, PGT-AO facilitates research on the origin of aneuploidies in preimplantation embryos and their clinical outcome. Trial registration number not applicable

Technical Considerations for the Surgical Management of a C2 Spinal Cord Hemangioblastoma and Subjacent Cervical Spondylotic Myelopathy: A 2-Dimensional Operative Video.

Hemangioblastomas are characterized as benign tumors of the central nervous system and are typically associated with von Hippel-Lindau disease in 20% to 30% of patients.1 Spinal hemangioblastomas are rare entities accounting for 2.1% of spinal cord tumors and are most frequently observed in the cervical spinal region.1-4 Treatment interventions include microsurgical resection and stereotactic radiosurgery.5 Understanding the granular detail of surgical management in these complex cases is necessary for optimal clinical outcomes. In this 2-dimensional operative video, we detail the technical nuances for resection of a World Health Organization Grade I hemangioblastoma in the upper cervical spine of a 51-year-old man. The lesion and severe adjacent canal stenosis resulted in extensive spinal cord compression, causing him to experience progressive myelopathic symptoms and neurological deficits. A C1-C7 laminectomy provided exposure of the hemangioblastoma and adequate decompression of the subjacent spondylotic disease. Intraoperative ultrasound was used to localize the tumor and perform a targeted durotomy. The sunburst-colored lesion was eccentric to the left side of C1-C2 and found in the epi-pial region, with pial thickening present in the surrounding area. The feeding vessels and deep draining vein were coagulated and cut. Low-power suction was used for traction/counter-traction dissection of the tumor planes. Owing to a multilevel laminectomy having been performed, hardware placement was performed from C2-T1. Adequate placement of all screws was confirmed with intraoperative 3-dimensional image acquisition. The patient provided informed consent for the operation and for sharing his clinical information, including digital media, for publication; Institutional Review Board not required per institutional policy.

Clinical Workflow Algorithm for Preoperative Planning, Reduction and Stabilization of Complex Acetabular Fractures with the Support of Three-Dimensional Technologies.

Background: Treatment of pelvic injuries poses serious problems for surgeons due to the difficulties of the associated injuries. The objective of this research is to create a clinical workflow that integrates three-dimensional technologies in preoperative planning and performing surgery for the reduction and stabilization of associated acetabular fractures. Methods: The research methodology consisted of integrating the stages of virtual preoperative planning, physical preoperative planning, and performing the surgical intervention in a newly developed clinical workflow. The proposed model was validated in practice in a pilot surgical intervention. Results: On a complex pelvic injury case of a patient with an associated both-column acetabular fracture (AO/OTA-62C1g), we presented the results obtained in the six stages of the clinical workflow: acquisition of three-dimensional (3D) images, creation of the virtual model of the pelvis, creation of the physical model of the pelvis, preoperative physical simulation, orthopedic surgery, and imaging validation of the intervention. The life-size 3D model was fabricated based on computed tomography imagistics. To create the virtual model, the images were imported into Invesalius (version 3.1.1, CTI, Brazil), after which they were processed with MeshLab (version 2023.12, ISTI-CNR, Italy) and FreeCAD (version 0.21.2, LGPL, FSF, Boston, MA, USA). The physical model was printed in 21 h and 37 min using Ultimaker Cura software (version 5.7.2), on an Ultimaker 2+ printing machine through a Fused Deposition Modeling process. Using the physical model, osteosynthesis plate dimensions and fixation screw trajectories were tested to reduce the risk of neurovascular injury, after which they were adjusted and resterilized, which enhanced preoperative decision-making. Conclusions: The life-size physical model improved anatomical appreciation and preoperative planning, enabling accurate surgical simulation. The tools created demonstrated remarkable accuracy and cost-effectiveness that support the advancement and efficiency of clinical practice.

Success Rate of External Dacryocystorhinostomy With and Without Stent.

Dacryocystorhinostomy (DCR) is a procedure that bypasses an obstruction in the nasolacrimal duct system. DCR can be categorized into two primary techniques: external and endoscopic. This review aims to assess the success rate of external DCR procedures, both with and without the use of a stent. This study compared the outcomes of primary DCR with and without silicone intubation in multiple studies. The reviewed studies consistently showed that silicone intubation significantly improves the success rates of DCR, with success rates ranging from 80% to 95%. The involved studies suggest that silicone intubation offers specific advantages in complex cases involving distant and common canaliculus blockages and recurrent DCR surgeries. This review emphasizes that multiple studies have documented higher success rates of external dacryocystorhinostomy (DCR) when silicone tubes are utilized as stents. Furthermore, external DCR has been identified as the preferred procedure among medical professionals.

Are More Medically Complex Patients Who Undergo Complex Septorhinoplasty at an Increased Risk for Surgical Site Infection?

BackgroundProphylactic antibiotics are routinely prescribed by surgeons for their patients who undergo septorhinoplasty. However, the literature to support this remains controversial, especially in complex cases, those that require grafts, revision cases, extended surgical time, and an American Society of Anesthesiology (ASA) value greater than or equal to 3. PurposeThe study purpose was to evaluate for a potential association between increased anesthetic complexity and the risk for surgical site infection (SSI) following complex septorhinoplasty. Study DesignRetrospective cohort study of patients who underwent a complex septorhinoplasty between 2005 and 2022 at the Dallas Veterans Affairs Medical Center. Patients were excluded if they did receive a septorhinoplasty, did not follow up, or had insufficient records. Independent VariableAll patients were assigned an ASA value prior to surgery, with an ASA value of 3 serving as this study’s independent variable. Main Outcome VariableThe main outcome variable of interest was the development of a postoperative SSI, defined as findings consistent with cellulitis, purulence, or fistula development necessitating antibiotic treatment. CovariatesThe demographic covariates included patient age and sex. Clinical covariates included diabetes status, history of nasal trauma or surgery, and smoking status. The operative covariates were surgical duration, perioperative antibiotic, intraoperative complication, and type of cartilage graft used. AnalysesChi square analysis and t-tests were used for calculations with p-values < .05 being considered significant. ResultsA total of 182 patients were included in this study, 81 (45%) with an ASA ≤2 and 101 (55%) with an ASA of 3. A patient’s age (P <.01), male sex (P<.01), and a diagnosis of diabetes (P<.01) were associated with an ASA value of 3. In total there were 6 (3.3%) SSIs, with 2 (1%) occurring in those with an ASA of 3. An ASA value of 3 (P = .27, Relative Risk (RR) of .40) was not shown to be associated with an increased risk of SSI. ConclusionsOur results suggest that an ASA of 3 is not significant with regards to postoperative infection in patients who undergo a complex nasal septorhinoplasty and prophylactic postoperative antibiotics are not warranted.

Computational modeling of maxillary canine orthodontic movement

ObjectivesThe current study aims to explore the stress distribution along the roots of palatally positioned maxillary canines during orthodontic movement using a novel computational spring model. MethodsAn experimental analysis based on the spring-model was utilized to calculate Orthodontic Tooth Movement (OTM) and the resulting stresses. Two sets of experiments were conducted: the first set compared stresses on a canine resulting from a single force and a force-couple, while the second set simulated canines' traction during instantaneous movement with varying original tooth angulations using different off-the-shelf orthodontic coils. In total, 130 simulations were performed. ResultsThe model provided estimated stress distribution throughout the OTM with the expected movements, producing consistent outcomes with prior findings. In the first set of experiments, the force couple exhibited an average stress of 43 KPa, while a single force yielded 51 KPa on average. The maximum stress observed was 63 KPa for the force couple and 130 KPa for a single force. Note that the stress distribution attributed to the force couple was alleviated in comparison to the stress distribution caused by a single force. Force couples generated higher average stress. In the second experiment, the application of an occlusally-directed inclined force led to reduced stress levels overall. For instance, when a 200 g distal force was exerted on the canine, it generated an average stress of 20 KPa, whereas applying a force of the same magnitude in an occlusal-distal direction resulted in a lower average stress of 15.5 KPa. ConclusionsLower average stress levels when using a force couple indicate that larger loads might be safely applied for rotational movements. Given that areas under maximal stress are prone to damage, orthodontic treatment planning should carefully consider stress distribution to minimize potential harm in these high-stress zones. The results also suggest that force couples enable the use of stronger forces than a single force. Additionally, it is advisable to extrude the tooth initially before starting any horizontal movement towards the target position. Clinical significanceGiven that orthodontic treatment often relies on virtual planning, incorporating a variety of methods to evaluate stress distribution within the treatment strategy could offer numerous benefits. Such an approach holds the potential to improve both the efficiency and safety of orthodontic treatments, especially in complex cases that require the application of high forces.