Which Bank is the "Central" Bank? An Application of Markov Theory to the Canadian Large Value Transfer System

We use a method similar to Google's PageRank procedure to rank banks in the Canadian Large Value Transfer System (LVTS). Along the way we obtain estimates of the payment processing speeds for the individual banks. These differences in processing speeds are essential for explaining why observed daily distributions of liquidity differ from the initial distributions, which are determined by the credit limits selected by banks.Payment, clearing, and settlement systems

A framework for developing feature-rich software systems

In response to changing requirements and other environmental influences, software systems are increasingly developed incrementally. Successful implementation of new features in existing software is often difficult, whilst many software systems simply `break' when features are introduced. Size and complexity of modern software, poor software design, and lack of appropriate tools are some of the factors that often confound the issue. In this paper, we report on a successful industrial experience of evolving a feature-rich program analysis tool for dependable software systems. The experience highlights the need for a development framework to maintain rich traceability between development artifacts, and to satisfy certain minimal necessary conditions of artifacts during and after the implementation of a new feature

The Dens: A Review of its Diverse Nomenclature and a Recommended Simplified Terminology.

Pathology of the dens, such as fractures, demands precise terminology so that communication between physicians are succinct, diagnoses are accurate, and treatment strategies exact. This review aims to summarize the various terms used to describe the parts of the dens and recommend the ideal terminology. Using standard search engines, English language publications were searched for the many terms used to describe parts of the dens. A multitude of terms was identified with many demonstrating overlaps. Terms identified included apex, tip, apicodental, subdental, dentocentral and odontocentral junctions, peg, waist, base, neck, shaft, shoulder, and stem. Exact terminology is necessary when diagnosing or treating patients with pathology of or near the dens. The authors suggest simplified terminology for describing the parts of the dens that can be used in the future in order to be unequivocal and to avoid confusion when classifying and communicating fractures through its parts

The new onset of dysphagia four years after anterior cervical discectomy and fusion: Case report and literature review.

Background: Dysphagia is a common complication immediately following anterior cervical spine surgery. However, its onset more than 1-year postoperatively is rare. Case Description: A 45-year-old male initially underwent a C3-4 and C5-6 anterior cervical discectomy and fusion (ACDF). At age 49, 4 years later, he presented with worsening dysphagia accompanied by neck and right upper extremity pain. Radiographs demonstrated an extruded left C3 screw, which had migrated into the prevertebral soft tissues at the C4-C5 level; there was also loosening of the right C3 screw. The subsequent barium swallow study revealed that the screw was embedded in the pharyngeal wall. The patient required a two-stage operation; first, to remove the anterior instrumentation, and second, to perform a posterior instrumented C2-T2 fusion. Conclusion: A barium swallow study and other dynamic imaging are a valuable component of the diagnostic workup and therapeutic intervention to evaluate the delayed onset dysphagia following an ACDF

A Previously Unreported Arterial Variant of the Suboccipital Region Based on Cadaveric Dissection.

Introduction Several arterial variants have been reported to occur around the posterior arch of the atlas. Understanding the various anomalies and diagnosing them preoperatively can dramatically reduce the risk of surgical insult during neurosurgical procedures. Herein we report a case of an arterial variant found just below the posterior arch of C1. Case Report During the routine dissection of the suboccipital region via a posterior approach, an unusual bulge was identified just inferior to the inferior capitis oblique muscle. With further dissection, the structure was identified as a tortuous internal carotid artery. Conclusion Arterial variants around the posterior arch of C1 are surgically significant and can result in catastrophic injuries if unappreciated. Most of these variants will be related to the vertebral artery. To our knowledge, an arterial variant of the internal carotid artery in this location, as reported herein, has not been previously reported

Quality and Clinical Care Development in Spine Surgery-Connecting the Dots: An Expanded Clinical Narrative.

Our health care system is an evidenced-based quality-centric environment. Pursuit of quality is a process that encompasses knowledge development and care advancements through collaboration and expertise. Depicted here is the foundational knowledge, process, and contributions that hallmark successful clinical quality programs. Beginning with methodology, followed by process and form, we create the foundational knowledge and exemplars demonstrating framework and continuum of process in pursuit and attainment of successful clinical quality and care development for patients. Although our protocol has been devised for complex spine care, this could be implemented across all health care specialties to provide individualized and high-quality care for all current and future patients, all while creating a culture of accountability for physicians

Avoiding the Esophageal Branches of the Recurrent Laryngeal Nerve During Retractor Placement: Precluding Postoperative Dysphagia During Anterior Approaches to the Cervical Spine.

Study Design: Anatomical cadaver study. Objectives: Postoperative dysphagia is a significant complication following anterior approaches to the cervical spine and the etiology of this complication is poorly understood. Herein, we studied the esophageal branches of the recurrent laryngeal nerves to improve understanding of their anatomy and potential involvement in dysphagia. Methods: Ten fresh frozen cadaveric human specimens were dissected (20 sides). All specimens were adults with no evidence of prior surgery of the anterior neck. The recurrent laryngeal nerves were identified under a surgical microscope and observations and measurements of their esophageal branches made. Results: For each recurrent laryngeal nerve, 5-7 (mean 6.2) esophageal branches were identified. These branches ranged from 0.8 to 2.1 cm (mean 1.5 cm) in length and 0.5 to 2 mm (mean 1 mm) in diameter. They arose from the recurrent laryngeal nerves between vertebral levels T1 and C6. They all traveled to the anterior aspect of the esophagus. No statistical differences were seen between left and right sides or between sexes. Conclusion: The esophageal branches of the recurrent laryngeal nerve have been poorly described and could contribute to complications such as swallowing dysfunction following anterior cervical discectomy and fusion procedures. Therefore, a better understanding of their anatomy is important for spine surgeons. Our study revealed that these branches are always present on both sides and the anterior surface of the esophagus should be avoided while retracting it in order to minimize the risk of postoperative dysphagia

Factors Associated With C5 Palsy Following Cervical Spine Surgery: A Systematic Review.

Study Design: Systematic review. Objectives: C5 palsy (C5P) is a not uncommon and disabling postoperative complication with a reported incidence varying between 0% and 30%. Among others, one explanation for its occurrence includes foraminal nerve root tethering. Although different risk factors have been reported, controversy about its causation and prevention persists. Inconsistent study findings contribute to the persistent ambiguity leading to an assumption of a multifactorial nature of the underlying C5P pathophysiology. Here, we report the results of a systematic review on C5P with narrow inclusion criteria in the hope of elucidating risk factors for C5P due to a common pathophysiological mechanism. Methods: Electronic databases from inception to March 9, 2019 and references of articles were searched. Narrow inclusion criteria were applied to identify studies investigating demographic, clinical, surgical, and radiographic factors associated with postoperative C5P. Results: Sixteen studies were included after initial screening of 122 studies. Eighty-four risk factors were analyzed; 27 in ≥2 studies and 57 in single studies. The pooled prevalence of C5P was 6.0% (range: 4.2%-24.1%) with no consistent evidence that C5P was associated with demographic, clinical, or specific surgical factors. Of the radiographic factors assessed, specifically decreased foraminal diameter and preoperative cord rotation were identified as risk factors for C5P. Conclusion: Although risk factors for C5P have been reported, ambiguity remains due to potentially multifactorial pathophysiology and study heterogeneity. We found foraminal diameter and cord rotation to be associated with postoperative C5P occurrence in our meta-analysis. These findings support the notion that factors contributing to, and acting synergistically with foraminal stenosis increase the risk of postoperative C5P