Evaluating the impact of skill development for drowning prevention: a relationship-building approach to community engagement.

OBJECTIVE: Evaluate the impact of a broadened theoretical and empirical model of community engagement aimed at coastal drowning prevention via relationship building between lifeguards and beachgoers through the delivery of skill development sessions on the beach. SETTING: A lifeguard-patrolled beach in Lorne, Victoria, Australia, during the 2023 peak summer holiday season. METHODS: In total, 12 skill development sessions were delivered by teams of lifeguards and risk researchers to beachgoers. Sessions were codesigned by the research team and shared with lifeguards beforehand to review and include lifeguards' interpretations of localised risk during delivery. In total, 85 survey interviews were conducted with self-selecting beachgoers post participation. RESULTS: In total, 79 participants (93%) enjoyed participating in the session(s) and 77 participants (91%) reported learning something new. Learning how to identify rip current (n=59) and escape a rip current (n=40) were the two most commonly learnt skills. Participants' intended changes in future beachgoing behaviours (n=46) include asking lifeguards at patrolled beaches how to identify site-specific (rip current) risk (n=11) and attempting to identify a rip current before entering the water (n=10). The spillover effects of participation include sharing what participants had learnt with family and friends. CONCLUSIONS: Creating a dialogic model of collaboration via participatory community engagements between lifeguards and researchers with the beachgoing public can successfully prompt learning drowning prevention skills. These skills are required when navigating dynamic coastal hazards at unpatrolled beaches. Supporting lifeguards and life-savers to provide skill development expands the ways that life-saving services can engage the public, including measurement of lifeguards' contributions to coastal drowning prevention.

Associating dose-volume characteristics with theoretical radiobiological metrics for rapid Gamma Knife stereotactic radiosurgery plan evaluation.

PURPOSE: To examine general dose-volume characteristics in Gamma Knife (GK) plans which may be associated with higher tumor control probability (TCP) and equivalent uniform dose (EUD) using characteristic curve sets. METHODS: Two sets of dose-volume histograms (DVHs) were exported alongside an analytical purpose-generated DVH: (a) single-shot large collimator (8 or 16 mm) emulated with multiple shots of 4 mm collimator. (b) shot-within-shot (SWS) technique with isodose lines (IDLs) of 40-75%. TCP, average dose, EUD in single-fraction (EUDT ) and 2 Gy fractionated regimens (EUDR ) were examined for trends with cumulative DVH (cDVH) shape as calculated using a linear-quadratic cell survival model (α/ß = 10.0 Gy, N0  = 1 × 106 ) with both α = 0.20 Gy-1 and α = 0.23 Gy-1 . RESULTS: Using α = 0.20 Gy-1 (α = 0.23 Gy-1 ), plans in the analytical set with higher shoulder regions had TCP, EUDT , EUDR increased by 180%, 5.9%, 10.7% (11.2%, 6.3%, 10.0%), respectively. With α = 0.20 Gy-1 (α = 0.23 Gy-1 ), plans with higher heels had TCP, EUDT , EUDR increased by 4.0%, <1%, <1% (0.6%, <1%, <1%), respectively. In emulating a 16 (8) mm collimator, 64 (12) shots of the small collimators were used. Plans based on small collimators had higher shoulder regions and, with α = 0.20 Gy-1 (α = 0.23 Gy-1 ), TCP, EUDT , EUDR was increased up to 351.4%, 5.0%, 8.8% (270.4%, 5.0%, 6.8%) compared with the single-shot large collimator. Delivery times ranged from 10.2 to 130.3 min. The SWS technique used 16:8 mm collimator weightings ranging from 1:2 to 9.2:1 for 40-75% IDL. With α = 0.20 Gy-1 (α = 0.23 Gy-1 ), the 40% IDL plan had the highest shoulder with increased TCP, EUDT , EUDR by 130.7%, 9.6%, 17.1% (12.9%, 9.1%, 16.4%) over the 75% IDL plan. Delivery times ranged 6.9-13.8 min. CONCLUSIONS: The magnitude of the shoulder region characteristic to GK cDVHs may be used to rapidly identify superior plan among candidates. Practical issues such as delivery time may require further consideration.

Matrix-Induced Autologous Chondrycte Implantation for a Glenoid Chondral Defect: A Case Report.

CASE: We describe the case of a 33-year-old man who had a 1.5 × 2 cm chondral defect of the right glenoid that that was discovered on arthroscopy and was successfully treated with matrix-induced autologous chondrocyte implantation (MACI). At 2 years postoperatively, the patient's Constant score and American Shoulder and Elbow Surgeons (ASES) shoulder score improved by 44 and 51.6 points, respectively. CONCLUSION: Chondral lesions of the glenoid are rare and are a challenge to manage. This case represents a successful outcome with MACI, thus providing surgeons with an option for treating these difficult problems.

Histologic evaluation of a biopsy specimen obtained 3 months after rotator cuff augmentation with GraftJacket Matrix.

Understanding the cellular response to a biologic graft used in rotator cuff applications is important because foreign-body reactions and inflammation complications have historically been seen with xenograft-derived grafts. The purpose of this study was to histologically evaluate a biopsy specimen taken from a rotator cuff of a 62-year-old man 3 months after augmentation with an acellular human dermal graft, GraftJacket Matrix-MaxForce Extreme (Wright Medical Technology, Arlington, TN). The graft material was intact and filled with numerous elastic fibers and blood vessels. Extensive host cellular infiltration was evident along the margins of the graft, whereas the more central regions were more sparsely populated. Calcification and infection were not evident. There was little to no inflammatory response. The orientation of the collagen fibers indicated early organization of new tissue. The incorporation of the GraftJacket Matrix-MaxForce Extreme evidenced by cellular infiltration, alignment of collagen fibers, and blood vessel ingrowth shows that this graft exhibits key biologic factors of the remodeling process when used as an augmentation device in rotator cuff repair.

The 23-point arthroscopic examination of the hip: basic setup, portal placement, and surgical technique.

The 23-point arthroscopic examination of the hip has been used for more than 400 arthroscopic hip procedures. It ensures that all components of the hip are carefully inspected and allows for proper documentation. It is vital that a precise knowledge of hip anatomy and common portal placement is coupled with proper patient selection, sound preoperative planning, and a consistent arthroscopic technique in order to maximize clinical outcomes. The 23-point arthroscopic examination of the hip uses 3 standard portals (anterior, anterolateral, and posterolateral) that provide a systematic method of examination of the key structures of the central and peripheral hip joint. The points are divided up into groups based on the portal through which they are viewed. The 23-point arthroscopic examination of the hip is reproducible, and offers some standardization within the evolving field of hip arthroscopy. It provides a consistent routine for hip arthroscopy that has yet to be published. Using this standardized examination can assist with the diagnostic accuracy of hip arthroscopy.

Arthroscopic replacement of massive, irreparable rotator cuff tears using a GraftJacket allograft: technique and preliminary results.

PURPOSE: Our purpose was to assess the short-term results and describe the technique of arthroscopic repair of irreparable rotator cuff tears by use of a GraftJacket allograft (Wright Medical Technology, Arlington, TN). METHODS: Between March 2003 and February 2004, 16 patients with massive, contracted, immobile rotator cuff tears were treated with arthroscopic placement of a GraftJacket allograft by a single surgeon. Patients were followed up for 1 to 2 years. All were evaluated preoperatively and postoperatively by use of the modified University of California, Los Angeles scoring system, Constant score, and Simple Shoulder Test. Magnetic resonance imaging was performed postoperatively at 3 months and 1 year. RESULTS: At a mean follow-up of 26.8 months (range, 12 to 38 months), 15 of 16 patients were satisfied with the procedure. The mean University of California, Los Angeles score increased from 18.4 preoperatively to 30.4 postoperatively (P = .0001). The Constant score increased from 53.8 to 84.0 (P = .0001). Statistically significant improvements were seen in pain, forward flexion, and external rotation strength. Thirteen patients had full incorporation of the graft into the native tissue as documented on magnetic resonance imaging. There were no complications in this cohort of patients. CONCLUSIONS: Our study supports GraftJacket allograft as a viable solution for surgical salvage in select cases of massive, irreparable rotator cuff pathology. This treatment option may provide patients with decreased pain and increased function despite a previously irreparable rotator cuff tear. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The transverse humeral ligament: a separate anatomical structure or a continuation of the osseous attachment of the rotator cuff?

BACKGROUND: No study to date has isolated the anatomical nature of the transverse humeral ligament and its relationship to the biceps tendon and the anterosuperior portion of the rotator cuff. HYPOTHESIS: There is no separate identifiable transverse humeral ligament, but rather the fibers covering the intertubercular groove are composed of a sling formed by fibers from the subscapularis and supraspinatus tendons. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 14 shoulder examinations were performed on 7 matched pairs of fresh-frozen cadaveric shoulders. Magnetic resonance imaging scans were performed, followed by gross and microscopic anatomical dissection. RESULTS: In the location of the transverse humeral ligament, magnetic resonance imaging and gross dissection revealed the continuation of superficial fibers of the subscapularis tendon from the tendon body across the intertubercular groove to attach to the greater tuberosity, whereas deeper fibers of the subscapularis tendon inserted on the lesser tuberosity. Longitudinal fibers of the supraspinatus tendon and the coracohumeral ligament were also noted to travel the length of the groove, deep to the other interdigitating fibers but superficial to the biceps tendon. Histologic studies confirmed these gross dissection patterns of fiber attachment and also revealed the absence of elastin fibers, which are more commonly seen in ligamentous structures and are typically absent from tendinous structures. CONCLUSION: There is no identifiable transverse humeral ligament, but rather the fibers covering the intertubercular groove are composed of a sling formed mainly by the fibers of the subscapularis tendon, with contributions from the supraspinatus tendon and the coracohumeral ligament. CLINICAL RELEVANCE: According to our findings, dislocations of the long head of the biceps must disrupt at least the deep fibers of the annular sling created mainly by the subscapularis tendon insertion. This finding provides anatomical support for the findings of a positive biceps tendon subluxation or dislocation and subscapularis tear during glenohumeral arthroscopy with a normal-appearing subscapularis during open surgery or subacromial arthroscopy.

Resin-based composite coronal augmentation of diminutive lateral incisors: an update.

The 2 cases presented here document methods of enlarging diminutive lateral incisors using bonded resin-based composite materials. Former methods are reviewed, and descriptions of a matrix strip stabilization technique and the use of a self-etching adhesive agent are included.

A contemporary dose selection algorithm for stereotactic radiosurgery in the treatment of brain metastases - An initial report.

SUMMARY: Indications and treatment goals for SRS have changed since the publication of RTOG 90-05. We present initial retrospective outcomes from a new dose selection algorithm in use at our institution felt to be more contemporary with doses being used in the radiosurgery community today and report our local control and toxicity outcomes. This dose selection algorithm will be subject to a forthcoming prospective phase 2 trial. INTRODUCTION: To evaluate safety and efficacy of an institutional dose selection algorithm in the treatment of brain metastases (BM) with single fraction radio-surgery (SRS). METHODS AND MATERIALS: The medical records of 65 patients with ≤10 BM treated with GK at our institution between April 2012 and October 2012 were reviewed retrospectively. The prescription doses used in this study ranged from 16-22Gy and were based upon RTOG 90-05 guideline doses subsequently modified at our institution depending on lesion number, lesion volume, institutional experience and prior history of whole brain radiation therapy (WBRT). Primary endpoint was local recurrence (LR) with additional outcomes measured including distant intracranial recurrence (DIR), death without local recurrence (DWLR) and alive and disease free (ADF). Fine Gray competing risk analysis was used to examine factors affecting local recurrence. RESULTS: Median follow up was 8.9 months (range 1.0-29.6months) and 12 month overall survival was 37% (95% CI 24.9-49.1%). Overall local recurrence rate was 7.7%. On competing risks regression analysis, no variable was significantly associated with local recurrence, including previous whole brain radiotherapy (WBRT), (SHR 1.21 [95%CI 0.13-11.5], p=0.87 and radioresistant versus radiosensitive histology (SHR 0.51 [95% CI 0.06-7.73], p=0.55). No patient developed grade 3 or higher neurotoxicity at 12 months following GK. CONCLUSIONS: Initial local control and toxicity results from our institutional dose selection algorithm are reported here. Comparison of our results with RTOG 90-05 is difficult due to significant differences in the patient population and their treatments. The applicability of this algorithm merits further investigation across multiple centers for the purpose of treatment and clinical trial standardization in single fraction SRS and will be the subject of a forthcoming phase 2 prospective study within our own institution.

The impact of cobalt-60 source age on biologically effective dose in high-dose functional Gamma Knife radiosurgery.

OBJECTIVE Functional Gamma Knife radiosurgery (GKRS) procedures have been increasingly used for treating patients with tremor, trigeminal neuralgia (TN), and refractory obsessive-compulsive disorder. Although its rates of toxicity are low, GKRS has been associated with some, if low, risks for serious sequelae, including hemiparesis and even death. Anecdotal reports have suggested that even with a standardized prescription dose, rates of functional GKRS toxicity increase after replacement of an old cobalt-60 source with a new source. Dose rate changes over the course of the useful lifespan of cobalt-60 are not routinely considered in the study of patients treated with functional GKRS, but these changes may be associated with significant variation in the biologically effective dose (BED) delivered to neural tissue. METHODS The authors constructed a linear-quadratic model of BED in functional GKRS with a dose-protraction factor to correct for intrafraction DNA-damage repair and used standard single-fraction doses for trigeminal nerve ablation for TN (85 Gy), thalamotomy for tremor (130 Gy), and capsulotomy for obsessive-compulsive disorder (180 Gy). Dose rate and treatment time for functional GKRS involving 4-mm collimators were derived from calibrations in the authors' department and from the cobalt-60 decay rate. Biologically plausible values for the ratio for radiosensitivity to fraction size (α/ß) and double-strand break (DSB) DNA repair halftimes (τ) were estimated from published experimental data. The biphasic characteristics of DSB repair in normal tissue were accounted for in deriving an effective τ1 halftime (fast repair) and τ2 halftime (slow repair). A sensitivity analysis was performed with a range of plausible parameter values. RESULTS After replacement of the cobalt-60 source, the functional GKRS dose rate rose from 1.48 to 2.99 Gy/min, treatment time fell, and estimated BED increased. Assuming the most biologically plausible parameters, source replacement resulted in an immediate relative BED increase of 11.7% for GKRS-based TN management with 85 Gy, 15.6% for thalamotomy with 130 Gy, and 18.6% for capsulotomy with 180 Gy. Over the course of the 63-month lifespan of the cobalt-60 source, BED decreased annually by 2.2% for TN management, 3.0% for thalamotomy, and 3.5% for capsulotomy. CONCLUSIONS Use of a new cobalt-60 source after replacement of an old source substantially increases the predicted BED for functional GKRS treatments for the same physical dose prescription. Source age, dose rate, and treatment time should be considered in the study of outcomes after high-dose functional GKRS treatments. Animal and clinical studies are needed to determine how this potential change in BED contributes to GKRS toxicity and whether technical adjustments should be made to reduce dose rates or prescription doses with newer cobalt-60 sources.

Equivalent whole brain dose for patients undergoing gamma knife for multiple lesions.

INTRODUCTION: The advent of new radiosurgical technology has enabled the treatment of patients with larger numbers of brain metastases. At what point the whole brain doses delivered in single fraction radiosurgical treatment begin to approximate a fraction of whole brain radiotherapy is unknown. Measuring the equivalent whole-brain dose for multiple lesions may yield useful clinical insights. METHODS: Twelve representative patients were chosen from our institutional database, having undergone radiosurgery for multiple lesions. All patients were treated using the Leksell Gamma Knife Perfexion radiosurgical platform. The entire brain was contoured and mean whole brain dose (MWBD) was calculated. For each plan, all enhancing tumors were outlined and total volume of tumors recorded. RESULTS: A total of 33 treatments were administered. Three patients underwent radiosurgery a single time, one patient on two occasions, four patients on three occasions, and four patients on four occasions. Median number of lesions treated was 8 (range 1-41). Dose ranged from 18-22 Gy per lesion. The median MWBD per treatment was 1.4 Gy (range 0.2-7.6 Gy). Median total tumor volume was 4.3 cm3 (range 0.048 cm3-21.72 cm3). No patients with less than 25 lesions treated had a MWBD greater than 4 Gy. Total tumor volume was also associated with greater MWBD, albeit with a greater number of outliers. CONCLUSION: Both tumor number and volume were associated with increased MWBD. Patients with greater than 25 lesions treated per session or cumulative tumor volumes greater than 10 cm3 had MWBD's greater than 4 Gy. Furthermore, tumor location and proximity to vital structures are equally important to consider, highlighting the need for individualized treatment planning.

Comparison of an image registration technique based on normalized mutual information with a standard method utilizing implanted markers in the staged radiosurgical treatment of large arteriovenous malformations.

PURPOSE: To compare a noninvasive technique based on normalized mutual information for registering image sets associated with staged radiosurgical treatments of large arteriovenous malformations (AVMs), with a gold-standard method using radiographically evident markers implanted in the skull. METHODS: Nine patients receiving multistage treatment of large AVMs at the University of California at San Francisco (UCSF) gamma knife facility were included in this study. For each patient, the transformations of shot coordinates between a reference treatment stage and subsequent treatment stages were determined at UCSF, based on radiographically defined coordinates of implanted markers in each stereotactic space. A magnetic resonance (MR) image set was acquired for each treatment stage, and used for treatment planning. The two MR image sets for each treatment pair were sent to Yale for an unbiased, independent analysis of shot transformations. An image registration technique based on normalized mutual information was used to produce a single fused image study for each treatment pair. External copper sulfate fiducial markers for both image sets were evident on the fused images, allowing coordinates in both stereotactic systems to be defined. Coordinate transformation between the two systems was determined, based on digitized coordinates of seven common fiducial marker images. RESULTS: The average measured overall root-mean-square discrepancy between the Yale and UCSF transformed shot coordinates is 1.1 +/- 0.3 mm. The corresponding error in Yale transformed coordinates is 1.0 +/- 0.3 mm, assuming an inherent 0.5 mm error in the UCSF method. CONCLUSIONS: The normalized mutual information method can be used to obtain good image registration between successive sessions in staged treatments. Further improvements in the reported methodology are outlined. Because the mutual information method is less invasive than the implanted marker method, it may be preferable in many cases.

A technique to re-establish dose distributions for previously treated brain cancer patients in external beam radiotherapy.

Tumor recurrences or new tumors may develop after irradiation of local lesion(s) in the brain, and additional radiotherapy treatments are often needed for previously treated patients. It is critical to re-establish the dose distributions delivered during the previous treatment in the current patient geometry, so that the previous dose distributions can be accurately taken into consideration in the design of the current treatment plan. The difficulty in re-establishing the previous treatment dose distributions in the current patient geometry arises from the fact that the patient position at the time of reirradiation is different from that at the previous treatment session. Simple re-entry of the previous isocenter coordinates, gantry, and couch and collimator angles into the new treatment plan would result in incorrect beam orientations relative to the new patient anatomy, and therefore incorrect display of the previous dose distributions on the current patient anatomy. To address this issue, a method has been developed so that the previous dose distributions can be accurately re-established in the framework of the current brain treatment. The method involves 3 matrix transformations: (1) transformation of beams from machine coordinate system to patient coordinate system in the previous treatment; (2) transformation of beams from patient coordinate system in the previous treatment to patient coordinate system in the current treatment; and (3) transformation of beams from patient coordinate system in the current treatment to machine coordinate system. The transformation matrices used in the second transformation are determined by registration using a mutual information-based algorithm with which the old and new computed tomography (CT) scan sets are registered automatically without human interpretation. A series of transformation matrices are derived to calculate the isocenter coordinates, the gantry, couch, and collimator angles of the beams for the previous treatment in the current patient geometry, and the previous dose distributions are re-established on the current CT images. The method has been proven to be successful and robust.

Evaluation of a new monochloramine generation system for controlling Legionella in building hot water systems.

OBJECTIVE: To evaluate the efficacy of a new monochloramine generation system for control of Legionella in a hospital hot water distribution system. SETTING: A 495-bed tertiary care hospital in Pittsburgh, Pennsylvania. The hospital has 12 floors covering approximately 78,000 m(2). METHODS: The hospital hot water system was monitored for a total of 29 months, including a 5-month baseline sampling period prior to installation of the monochloramine system and 24 months of surveillance after system installation (postdisinfection period). Water samples were collected for microbiological analysis (Legionella species, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter species, nitrifying bacteria, heterotrophic plate count [HPC] bacteria, and nontuberculous mycobacteria). Chemical parameters monitored during the investigation included monochloramine, chlorine (free and total), nitrate, nitrite, total ammonia, copper, silver, lead, and pH. RESULTS: A significant reduction in Legionella distal site positivity was observed between the pre- and postdisinfection periods, with positivity decreasing from an average of 53% (baseline) to an average of 9% after monochloramine application (P<0.5]). Although geometric mean HPC concentrations decreased by approximately 2 log colony-forming units per milliliter during monochloramine treatment, we did not observe significant changes in other microbial populations. CONCLUSIONS: This is the first evaluation in the United States of a commercially available monochloramine system installed on a hospital hot water system for Legionella disinfection, and it demonstrated a significant reduction in Legionella colonization. Significant increases in microbial populations or other negative effects previously associated with monochloramine use in large municipal cold water systems were not observed.

Design of a consensus-derived synoptic operative report for lung cancer surgery.

BACKGROUND: For lung cancer surgery, a narrative operative report is the standard reporting procedure, whereas a synoptic-style report is increasingly utilized by healthcare professionals in various specialties with great success. A synoptic operative report more succinctly and accurately captures vital information and is rapidly generated with good intraobserver reliability. The objective of this study was to systematically develop a synoptic operative report for lung cancer surgery following a modified Delphi consensus model with the support of the Canadian thoracic surgery community. METHODS: Using online survey software, thoracic surgeons and related physicians were asked to suggest and rate data elements for a synoptic report following the modified Delphi consensus model. The consensus exercise-derived template was forwarded to a small working group, who further refined the definition and priority designation of elements until the working group had reached a satisfactory consensus. RESULTS: In all, 139 physicians were invited to participate in the consensus exercise, with 36.7%, 44.6%, and 19.5% response rates, respectively, in the three rounds. Eighty-nine elements were agreed upon at the conclusion of the exercise, but 141 elements were forwarded to the working group. The working group agreed upon a final data set of 180 independently defined data elements, with 72 mandatory and 108 optional elements for implementation in the final report. CONCLUSIONS: This study demonstrates the process involved in developing a multidisciplinary, consensus-based synoptic lung cancer operative report. This novel report style is a quality improvement initiative to improve the capture, dissemination, readability, and potential utility of critical surgical information.

Working in retirement: a brief report.

Despite the relatively large number of working retirees, very little research has focused specifically on their job experiences. This brief report aims to address this gap in the literature by examining what facets of workplace environment affect job satisfaction and engagement for people who are working in retirement. Data from the 2008 National Study of the Changing Workforce, a sample representative of United States workers, are used to compare workers aged 50 and above who consider themselves retired (N = 203) to those in the same age group who do not consider themselves retired (N = 936). Results suggest that although the economic security offered by the job is less important to job satisfaction and engagement among those who are working in retirement than it is for other older workers, their relationship with their supervisor may be more important. Implications of these findings are considered along with potential directions for future research.

A method for screening the temperature dependence of three-dimensional crystal formation.

Temperature is an important parameter controlling protein crystal growth. A new temperature-screening system (Thermo-screen) is described consisting of a gradient thermocycler fitted with a special crystallization-plate adapter onto which a 192-well sitting-drop crystallization plate can be mounted (temperature range 277-372 K; maximum temperature gradient 20 K; interval precision 0.3 K). The system allows 16 different conditions to be monitored simultaneously over a range of 12 temperatures and is well suited to conduct wide (approximately 20 K) and fine (approximately 3 K) temperature-optimization screens. It can potentially aid in the determination of temperature phase diagrams and run more complex temperature-cycling experiments for seeding and crystal growth.