Probabilistic projections of the stability of small tidal inlets at century time scale using a reduced complexity approach

Climate change is widely expected to affect the thousands of small tidal inlets (STIs) dotting the global coastline. To properly inform effective adaptation strategies for the coastal areas in the vicinity of these inlets, it is necessary to know the temporal evolution of inlet stability over climate change time scales (50–100 years). As available numerical models are unable to perform continuous morphodynamic simulations at such time scales, here we develop and pilot a fast, probabilistic, reduced complexity model (RAPSTA – RAPid assessment tool of inlet STAbility) that can also quantify forcing uncertainties. RAPSTA accounts for the key physical processes governing STI stability and for climate change driven variations in system forcing. The model is very fast, providing a 100 year projection in less than 3 seconds. RAPSTA is demonstrated here at 3 STIs, representing the 3 main Types of STIs; Permanently open, locationally stable inlet (Type 1); Permanently open, alongshore migrating inlet (Type 2); Seasonally/Intermittently open, locationally stable inlet (Type 3). Model applications under a high greenhouse gas emissions scenario (RCP 8.5), accounting for forcing uncertainties, show that while the Type 1 STI will not change type over the twenty-first century, the Type 2 inlet may change into a more unstable Type 3 system around mid-century, and the Type 3 STI may change into a less unstable Type 2 system in about 20 years from now, further changing into a stable Type 1 STI around mid-century. These projections underscore the need for future adaptation strategies to remain flexible.

P.231 A Quantitative Degenerative Lumbar Spondylolisthesis Instability Classification (DSIC) System to Reduce Variation in Surgical Treatment

Background: The Degenerative lumbar Spondylolisthesis Instability Classification (DSIC) system categorizes spondylolisthesis (stable, potentially unstable, unstable) based on surgeon impression. It does not contain objective criteria. Objective-1: Develop a quantitative-DSIC system from predetermined radiographic/clinical variables. Objective-2: Compare qualitative (surgeon-assigned) and quantitative (objective) DSIC Types. Objective-3: Determine proportion of patients receiving more invasive surgery than warranted based on the objective system. Methods: Patients from 8 centers were enrolled prospectively (2015–2020). Radiographic/clinical variables were collected and included/excluded from the quantitative DSIC system based on prior systematic review. Scores were converted to DSIC Types: 0-2 points (“Stable”; Type 1), 3 points (“Potentially Unstable”; Type 2), 4-5 points (“Unstable”; Type 3). Surgical procedures performed were compared to those suggested by the objective system. Results: Quantitative DSIC scores were calculated (309 patients). The score includes five variables: facet effusion, disc height, translation, disc angle, and low back pain. Quantitatively, 57% were stable, 34% potentially unstable, and 9% unstable patients. Qualitatively, 30% were stable, 53% potentially unstable, and 17% unstable patients. Surgeons assigned more instability than the objective scoring system in 42% of cases. More invasive surgery was performed in 57% of cases. Conclusions: Surgeons are more likely to categorize greater degrees of spinal instability than what is objectively scored.

Unstable Type III Wrisberg-type Lateral Discoid Meniscus: All-inside Arthroscopic Repair

Background: The Type III Wrisberg-type represents the rarest subtype of discoid meniscus. It exhibits a normal non-discoid “C”-shape with possible posterior horn hypertrophy, but meniscotibial ligaments and capsular restraints are lacking, leading to a clinical scenario of knee pain, popping, and catching due to meniscal hypermobility. Moreover, concomitant tears can be present due to repeated meniscal traumas. Indications: Type III Wrisberg-type lateral discoid meniscus with hypermobility, dislocation, or tear. Technique Description: Through standard arthroscopic portals, the meniscus is reduced in its anatomical position (if displaced). Abnormal mobility and anatomy should be noted. All-inside sutures are used in the posterior horn and body to stabilize the meniscus to the capsule and popliteus tendon. In the case of radial tears, horizontal stitches are used. Results: Patients are expected to return to sport approximately 4 to 5 months after the procedure with relief of pain, popping sensation, and knee locking. Conclusion: Arthroscopic all-inside repair is an effective treatment for unstable and displaced Type III Wrisberg-type lateral discoid meniscus. However, the diagnosis can be challenging, especially without frank meniscal dislocation.

New Clinical Classification for Ventricular Free Wall Rupture following Acute Myocardial Infarction

Ventricular free wall rupture (FWR) is a catastrophic complication after acute myocardial infarction (AMI). However, patients with FWR die of cardiac tamponade secondary to intrapericardial hemorrhage that can be treated if properly diagnosed. Unfortunately, FWR was still not diagnosed and classified quickly and accurately. The aim of this study was to present a new clinical classification for FWR. Seventy-eight patients with FWR after STEMI were enrolled in the study. We classified FWR, according to clinical situations after onset, into the cardiac arrest type, unstable type, and stable type. The cardiac arrest type was the most common type, accounting for about 83.3%. 90.8% of patients of this type were complicated with electromechanical dissociation at the time of FWR onset, and 100% of patients of this type died in the hospital. The unstable type was characterized by sudden clinical condition changes with moderate/massive pericardial effusion. In this study, 9.0% of patients were diagnosed as the unstable type. The average time from onset to death was 4.5 hours. This period was the “golden time” to rescue such patients. The stable types usually have stable hemodynamics, but may worsen, requiring rigorous detection of pericardial effusion and vital signs. In this study, 7.7% of patients were diagnosed as the stable type, and 83.5% of them survived in the hospital. The new clinical classification provides a basis for clinical diagnosis and treatment of FWR. The clinical application of the new classification is expected to improve the prognosis of FWR patients.