A new approach for trace analysis of guanidine compounds in surface water with resorcinarene-based ion chromatography columns.

Trace levels of pharmaceuticals have been detected in surface water and may pose a health risk to humans and other organisms. New chromatographic materials will help identify and quantify these contaminants. We introduce a new ion chromatographic (IC) material designed to separate cationic pharmaceuticals and report its ability to separate a group of guanidine compounds. Guanidine moieties are strongly basic and protonated under acid conditions, and therefore can potentially be separated on the newly designed stationary phase and detected by ion exchange chromatography. The new column packing material is based on glutamic acids bonded to resorcinarene moieties that in turn are bound to divinylbenzene macroporous resin. Detection limits in the range of 5-30 µg L(-1) were achieved using integrated pulsed amperometric detection (IPAD) for guanidine (G), methylguanidine (MG), 1,1-dimethylbiguanide (DMG), agmatine (AGM), guanidinobenzoic acid (GBA) and cimetidine (CIM). Suppressed conductivity (CD) and UV-vis detection resulted in limits of detection similar to IPAD, in the range of 2-66 µg L(-1), but were not able to detect all of the analytes. Three water sources, river, lake, and marsh, were analyzed and despite matrix effects, sensitivity for guanidine compounds was in the 100 µg L(-1) range and apparent recoveries were 80-96%. The peak area precision was 0.01-2.89% for IPAD, CD and UV-vis detection.

Complications and Learning Curve Associated with an Imageless Burr-Based (CORI) Robotic-Assisted Total Knee Arthroplasty System: Results from First 500 Cases.

Background: The use of robotic-assisted total knee arthroplasty (RA-TKA) is gaining traction. There is evidence to suggest that RA-TKA can help to optimize the precision and accuracy of implant positioning and that there may be protective effects on surrounding bony and soft tissues. Yet, there are important differences between the various RA-TKA systems currently on the market. One such newly introduced RA-TKA system uses imageless technology and performs bony cuts with the use of a burr-based device. The learning curve and complications unique to this system have yet to be assessed. Methods: We evaluated 500 consecutive RA-TKA cases using a newly developed burr-based and imageless system which were done by a single surgeon between the months of October 2021 and February 2023. Operative times were recorded and compared to the previous 150 conventional TKA cases allowing for the learning curve to be calculated using the CUSUM method. Intraoperative and postoperative complications were categorically profiled. Results: The learning curve of this RA-TKA system was found to be 6 cases. Intraoperative complications included unintended bony over resection (n = 3), soft tissue injury (n = 2), and robotic system hardware (n = 2) or software (n = 2) malfunction. Postoperative complications consisted of superficial pin site infection (n = 1) and periprosthetic fracture near the pin sites (n = 1). There were no identified cases of prosthetic joint infection, instability events, or wound complications. Conclusions: The learning curve and the complication profile of a newly introduced imageless and burr-based RA-TKA system were described. This information serves to guide surgeons in adopting this technology and can counsel them regarding the potential pitfalls and challenges associated with its integration into practice. The work sheds light on the complexity and learning curve of the recently released imageless burr-based RA-TKA system. This important information is intended to help surgeons accept this cutting-edge technology by providing advice on any errors and difficulties that can occur when integrating it into clinical practice. This information can help surgeons navigate the complexities of integrating this new burr-based robotic technology into knee replacement procedures, enabling them to make well-informed decisions and receive guidance.

Extracranial Vertebral Artery Injuries.

Paired vertebral arteries (VAs) travel from the subclavian artery through the cervical spine and into the intracranial space where they contribute to posterior cerebral circulation. Blunt and penetrating injuries to the cervical spine risk injury to the VA. Among the most feared complications of vertebral artery injury (VAI) is posterior circulation stroke. Appropriate screening and treatment of these injuries in the trauma setting remain vitally important to aid in the prevention of devastating neurologic sequelae. A robust knowledge of the VA anatomy is required for spine surgeons to avoid VAI during cervical spine approaches and instrumentation. Both anterior and posterior cervical spine surgeries can place the VA at risk. Careful preoperative assessment with the appropriate advanced imaging studies is necessary to verify the course of the VA in the cervical spine and thus prevent iatrogenic injury because anatomic variations along the course of the artery can prove hazardous if not properly anticipated. Iatrogenic VAI can be treated successfully with tamponade. However, in some cases, ligation, repair, or endovascular procedures may be indicated.

The Modified 5-Item Frailty Index: A Concise and Useful Tool for Assessing the Impact of Frailty on Postoperative Morbidity Following Elective Posterior Lumbar Fusions.

BACKGROUND: The modified 5-item frailty index (mFI-5) is a concise comorbidity-based risk stratification tool that has been shown to predict the occurrence of adverse outcomes following various orthopedic surgeries. METHODS: The 2012-2016 American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) dataset was used to identify patients undergoing an elective 1- to 2-level posterior lumbar fusion for degenerative lumbar pathology. The mFI-5 score was calculated based on the presence of the 5 co-morbidities: congestive heart failure within 30 days prior to surgery, insulin-dependent or noninsulin-dependent diabetes mellitus, chronic obstructive pulmonary disease or pneumonia, partially dependent or totally dependent functional health status at time of surgery, and hypertension requiring medication. Multivariate analysis was used to assess the independent impact of increasing mFI-5 score on postoperative morbidity while controlling for baseline clinical characteristics. RESULTS: Increasing mFI-5 score versus mFI-5 = 0 was associated with higher odds of any complication (mFI-5 ≥2: odds ratio [OR] 1.45; mFI-5 = 1: OR 1.22), 30-day readmissions (mFI-5 ≥2: OR 1.46; mFI-5 = 1: OR 1.18), and nonhome discharge (mFI-5 ≥2: OR 1.80; mFI-5 = 1: OR 1.16). Higher mFI-5 score was significantly associated with increased risks of superficial surgical site infection, deep surgical site infection, unplanned reoperation, any medical complication, pneumonia, unplanned intubation, postoperative ventilator use, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke, myocardial infarction, bleeding requiring transfusion, sepsis, and septic shock. CONCLUSIONS: Higher mFI-5 scores were associated with increased postoperative morbidity following elective 1- to 2-level posterior lumbar fusions.

Separation of uremic toxins from urine with resorcinarene-based ion chromatography columns.

People with chronic kidney disease suffer from uremic toxins which accumulate in their bodies. Detection and quantification of uremic toxins help diagnose kidney problems and start patient care. The aim of this research was to seek a new method to assist this diagnosis by trace level detection and separation of guanidine containing uremic toxins in water and urine. To detect and quantify the uremic toxins, new stationary phases for ion chromatography (IC) columns based on glutamic acid functionalized resorcinarenes bound to divinylbenzene macroporous resin were prepared. The new column packing material afforded separation of the five compounds: guanidinoacetic acid, guanidine, methylguanidine, creatinine, and guanidinobenzoic acid in 30min. Peak resolutions ranged from 7.6 to 1.3. Gradient elutions at ambient temperature with methanesulfonic acid (MSA) solution as eluent resulted in detection levels in water from 10 to 47ppb and in synthetic urine from 28 to 180ppb. Limits of quantification for the analytes using pulsed amperometric detection were 30-160ppb in water and 93-590ppb in urine. Trace levels of creatinine (1ppm) were detected in the urine of a healthy individual using the columns.