High lateral resolution vs molecular preservation in near-IR fs-laser desorption postionization mass spectrometry.

Ultrashort pulse length lasers operating in the near-infrared region show promise for submicrometer lateral resolution by laser desorption-based mass spectrometry (MS) imaging. However, these experiments must balance lateral resolution and molecular fragmentation since abundant atomic ions are observed at the high laser irradiances that can be generated by tightly focused ultrashort pulse laser beams. It is shown here that combining ultrashort pulse laser desorption with laser postionization (fs-LDPI) allows for a considerable increase of molecular ion signal while operating with lower laser irradiances, yielding the added benefit of reduced molecular fragmentation. This Letter presents several experimental results in support of the fs-LDPI approach for MS imaging. First, the lateral resolution for MS imaging of molecular species desorbed by ∼75 fs, 800 nm laser pulses was determined to be <2 µm for a simulated organic electronic device under vacuum. Next, the dependence of precursor ion survival on both desorption laser fluence and delay between desorption and photoionization laser pulses was observed for a small molecule desorbed from an organic multilayer that was originally devised as a model of a bacterial biofilm. When considered in light of recent results in the literature (Milasinovic et al. J. Phys. Chem. C 2014, DOI: 10.1021/jp504062u), these experiments demonstrate the potential for submicrometer spatial resolution MS imaging by fs-LDPI.

The Impact of Financial Education on Stress Among Orthopaedic Surgeons.

BACKGROUND: Financial stress has been an increasing area of concern for residents and attendings. The primary goal of this study was to determine the financial education level and differentiate financial outcome measures of orthopaedic surgery residents and attendings. METHODS: A survey of all residents and attendings of the 201 Accreditation Council for Graduate Medical Education (ACGME)-accredited orthopaedic surgery programs in the United States. RESULTS: Total participation in the study was 118 residents (postgraduate year (PGY) 1-5), three fellows (PGY 6), and 57 attending orthopaedic surgeons. A significant difference existed between average current financial stress scores between residents versus attending (2.32 vs 1.17), but not Doctor of Medicine (MD) versus Doctor of Osteopathic Medicine (DO) attendings (0.96 vs 1.67) and MD versus DO residents (2.25 vs 2.50). There was a significant difference in average future financial stress scores between residents and attendings (1.85 vs 1.44) and MD vs DO residents (1.61 vs 2.25) but no difference between MD vs DO attending (1.31 vs 1.63). Residents' confidence in financial knowledge compared to college graduates had a significantly negative Pearson coefficient with current financial stress score, while the attending group was not significant. CONCLUSIONS: Orthopaedic residents and attending physicians' financial stress levels are positively correlated with the amount of student debt they hold. Most residents who currently have no personal finance education offered in their residency would likely attend a personal finance course if offered. Decreasing the amount of debt held by residents, increasing their financial knowledge, and helping them develop good financial habits would likely lead to a decrease in financial stress.

Thoracic Spinal Stenosis From Calcified Ligamentum Flavum.

Background: Calcification of the ligamentum flavum is a rare cause of spinal stenosis. The process can occur at any level in the spine, often presents with local pain or radicular symptoms, and is a distinct process from ossification of the spinal ligaments in pathogenesis and treatment approach. Few case reports have described multiple level involvement in the thoracic spine that results in sensorimotor deficits and myelopathy. Case Report: A 37-year-old female presented with progressive sensorimotor deficits from T3 distally that resulted in complete sensory deficits and diminished lower extremity strength. Computed tomography and magnetic resonance imaging demonstrated calcification of the ligamentum flavum from T2-T12 with severe spinal stenosis at T3-T4. She underwent T2-T12 posterior laminectomy with ligamentum flavum resection. Postoperatively, she had complete motor strength return and was discharged home for outpatient therapy. Her residual sensory deficits continued to improve with time after decompression and excision of the calcified ligamentum flavum. Conclusion: This case is unique in that the calcific process involved nearly the entire thoracic spine. The patient had dramatic improvement in her symptoms following resection of the involved levels. The case adds a severe manifestation of calcification of the ligamentum flavum with a surgical outcome to the literature.

Refractory compartment syndrome after antivenom administration for an Eastern Diamondback Rattlesnake bite requiring fasciotomy for limb salvage: A case report.

Case: 56-year-old male who developed post-snakebite compartment syndrome (PSCS) of the upper extremity which was refractory to antivenom administration. He had elevated compartment pressure measurements in his upper extremity. He underwent open fasciotomy for the compartment syndrome, followed by delayed primary closure and skin grafting. He now has two years of follow-up with a functional upper extremity. Conclusion: This is a case of a patient who suffered post-snakebite compartment syndrome from his pet Eastern Diamondback Rattlesnake. This case highlights the importance of correctly diagnosing compartment syndrome and validates fasciotomy as a treatment measure for confirmed post-snakebite compartment syndrome (PSCS).

Indications and Interpretation of Stress Radiographs in Supination External Rotation Ankle Fractures.

Introduction In supination external rotation (SER) ankle fractures with an intact medial malleolus, stability hinges upon the competence of the deltoid ligament. The purpose of this study is to define the indications and establish criteria for a positive stress radiograph. Methods This is a prospective study of 27 isolated SER lateral malleolar fractures with a reduced ankle mortise. Pain and swelling were noted about the medial ankle, followed by an ultrasound to evaluate the integrity of the deltoid ligament. Static and stress radiographs were performed on both the fractured and contralateral ankles. Results Fourteen patients were normal on ultrasound examination, eight had partial tears, and five had full-thickness tears. The difference in the level of pain to palpation postero-medially between the complete tear (7 +/- 1) and the partial tear (1.3 +/- 2.4) group was significant (p < .001). The negative predictive values for medial swelling and tenderness were 93% and 100%, respectively. Sensitivity and specificity for medial clear space on stress radiograph (fracture (fx)) > 5.0 mm were both 100% while a 2.5 mm or greater change to the contralateral side yielded a sensitivity of 100% and specificity of 95%. Conclusion The lack of significant medial pain, as well as swelling, implies the absence of a complete ligament tear and eliminates the need for stress examination. Conversely, the presence of medial signs of injury is suggestive, but not pathognomonic for a complete deltoid tear. Medial clear space (MCS) variability prompts to recommend a minimum of 2.5 mm on stress radiographs compared to the contralateral side as indirect evidence for a complete tear of the deltoid ligament.

Percutaneous Treatment of Locked Pubic Symphysis with the Anterior Subcutaneous Pelvic Fixator (INFIX): A Case Report.

CASE: A 54-year-old woman was involved in a motor vehicle collision and sustained a lateral compression type 1 pelvic ring fracture with pubic symphyseal dislocation or a "locked pubic symphysis." Her injury failed to reduce with closed reduction maneuvers under anesthesia and necessitated a percutaneous reduction using a distraction force applied through supra-acetabular placed pedicle screws. This anterior subcutaneous internal pelvic fixator (INFIX) was also used to stabilize the injury. CONCLUSION: This is the first reported case where a locked pubic symphysis, which failed standard closed reduction measures, was reduced and stabilized through a percutaneous technique, using the INFIX.

Acute Correction of Femoral Malrotation After Intramedullary Nailing Using an Intraoperative Digital Protractor.

OBJECTIVE:  The goal of the study is to diagnose and accurately correct malrotation of femur fractures after intramedullary (IM) nailing. MATERIALS AND METHODS: An institutional review board (IRB) approved prospective study that was performed at a U.S. level 1 trauma center. After IM nailing of comminuted femur fractures, a computed tomography (CT) scanogram was routinely performed to detect the difference in the postoperative femoral version. Patients with malalignment greater than 15 degrees compared to the contralateral side were informed about the discrepancy and offered to have it acutely corrected. A four-pin technique was used: two Schanz pins were used for measuring angles and two different pins were used to turn and correct the malalignment. The pin in the distal fragment is placed directly under the nail to prevent shortening in comminuted fractures. The nail was unlocked either proximally for retrograde nails or distally for antegrade nails. The Bonesetter Angle application was used as a digital protractor to intraoperatively measure the two reference pins and correct the malrotation. Alternate holes were used for relocking the nail. All patients received a CT scanogram after correction. RESULTS:  19/128 patients with comminuted femoral fractures over five years with malrotations between 18 and 47 degrees were included in the study with an average malrotation of 24.7 + 8 degrees. All patients were corrected to an average of 4.0 +/- 2.1 degrees difference, as compared to the contralateral side (range 0-8). No patients required further surgeries to correct malrotation. CONCLUSION:  Comminuted fractures with malrotation >15 degrees after femoral nailing have an incidence of 15% at our institution. This technique provides an efficient and accurate correction method with the use of an intraoperative digital protractor, avoiding the need for revision IM nailing or osteotomies.

Neuroforaminal Stenosis in the Lumbosacral Spine: A Scoping Review of Pathophysiology, Clinical Manifestations, Diagnostic Imaging, and Treatment.

OBJECTIVE: To conduct the first scoping review of lumbosacral neuroforaminal stenosis with respect to the pathophysiology, symptomatic manifestations, diagnostic imaging, and treatment options. METHODS: A scoping literature review was conducted in accordance with the recommendations set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), with English language restrictions stipulated to include articles pertaining to lumbosacral neuroforaminal stenosis. Databases maintained by PubMed, National Library of Medicine, Cochrane Central Register of Controlled Trials (Ovid), Scopus (Elsevier), Web of Science (Thomson Reuters), and Google Scholar were queried from their inception date through December 2022. SUMMARY OF THE EVIDENCE: A total of 276 articles were reviewed and 29 articles were included within the study. Within these articles, the anatomic origins of neuroforaminal stenosis were reviewed in detail and the resulting clinical manifestations were discussed. Recent studies evaluating the efficacy of existing diagnostic imaging modalities were summarized, along with potential future methods to improve sensitivity for detecting this entity and measuring foraminal stenosis via novel imaging techniques. Based on the literature, the conservative management and surgical treatment of lumbosacral foraminal stenosis were discussed. CONCLUSIONS: Lumbar neuroforaminal stenosis represents a significant source of radicular pain that is often compounded by delayed diagnosis and incomplete treatment. This article represents the first scoping review of lumbosacral neuroforaminal stenosis with focus on diagnosis, management, and treatment for associated radicular pain. The goal is to reduce the incidence of untreated or unrecognized neuroforaminal stenosis in the setting of a complex decompression and fusion, as well as to promote minimally invasive surgery to address radicular pain from neuroforaminal stenosis. Recent advances in diagnostic imaging and surgical techniques have the potential to improve the timeliness and durability of patients' treatment options. Future directions for the diagnostic imaging of foraminal stenosis include efforts aimed at developing the nascent field of computerized mapping to reliably quantify stenosis and its impact on the exiting nerve root and associated dorsal root ganglia.

Predicting Factors for Blood Transfusion in Primary Total Knee Arthroplasty Using a Machine Learning Method.

INTRODUCTION: Acute blood loss anemia requiring allogeneic blood transfusion is still a postoperative complication of total knee arthroplasty (TKA). This study aimed to use machine learning models for the prediction of blood transfusion after primary TKA and to identify contributing factors. METHODS: A total of 2,093 patients who underwent primary TKA at our institution were evaluated using data extracted from the hospital quality improvement database to identify patient demographics and surgical variables that may be associated with blood transfusion. A multilayer perceptron neural network (MPNN) machine learning algorithm was used to predict risk factors for blood transfusion and factors associated with increased length of stay. Statistical analyses including bivariate correlate analysis, Chi-Square test, and Student t-test were performed for demographic analysis and to determine the correlation between blood transfusion and other variables. RESULTS: The results demonstrated important factors associated with transfusion rates, including preoperative hemoglobin level, preoperative creatinine level, length of surgery, simultaneous bilateral surgeries, tranexamic acid usage, American Society of Anesthesiologists Physical Status score, preoperative albumin level, ethanol usage, preoperative anticoagulation medications, age, and TKA type (conventional versus robotic-assisted). Patients who underwent a blood transfusion had a markedly greater length of stay than those who did not. The MPNN machine learning model achieved excellent performance across discrimination (AUC = 0.894). DISCUSSION: The MPNN machine learning model showed its power as a statistical analysis tool to predict the ranking of factors for blood transfusion. Traditional statistics are unable to differentiate importance or predict in the same manner as a machine learning model. CONCLUSION: This study demonstrated that MPNN for the prediction of patient-specific blood transfusion rates after TKA represented a novel application of machine learning with the potential to improve preoperative planning for treatment outcomes.

Efficacy and Outcome Measurement of iFactor/ABM/P-15 in Lumbar Spine Surgery: A Systematic Review.

STUDY DESIGN: Systematic Review. OBJECTIVES: To determine the efficacy and overall outcomes of iFactor/ABM/P-15 following lumbar spine surgery. METHODS: We performed a search of the Cochrane Library, Medline Ovid, PubMed, and SCOPUS databases from inception until August 2023. Eligible studies included outcomes of patients receiving iFactor following lumbar spine surgery. The primary outcomes of interest were fusion rates and iFactor efficacy after lumbar surgery in patients who received iFactor. Secondary outcomes included patient-reported outcomes and complication rates. RESULTS: A total of 766 titles were initially screened. After inclusion criteria were applied, 5 studies (388 patients) were included, which measured overall outcomes of iFactor/ABM/P-15 following lumbar spine surgery. These studies showed acceptable reliability for inclusion based on the Methodical Index for Non-Randomized studies and Critical Appraisal Skills Programme assessment tools. iFactor/ABM/P-15 facilitated significantly faster bone development in various procedures while maintaining favorable clinical outcomes compared to traditional grafts. CONCLUSIONS: This systematic review found that iFactor/ABM/P-15 use for lumbar spine surgery maintains similar managing patient-reported outcomes relative to other grafting methods. In regard to rates of fusion, iFactor/ABM/P-15 showed a significantly faster rate of fusion when compared to traditional grafts including allograft, autograft, demineralized bone matrix (DBM), and recombinant human bone morphogenetic protein-2 (rhBMP-2). Future multicenter randomized control trials with larger sample sizes are recommended to further assess iFactor/ABM/P-15 efficacy in lumbar spine surgery.