Generalized formula for the calculation of a probabilistic metric for random hardware failures in redundant subsystems

Abstract Background Distal radius fractures are one of the most common fractures seen in the elderly. The management of distal radius fractures in the elderly, especially patients older than 80 years, has not been well defined. The purpose of this study was to evaluate operative treatment of distal radius fractures in patients older than 80 years to determine functional outcomes and complication rates. Materials and Methods A retrospective review was performed to identify patients 80 years or older who were treated for a distal radius fracture with open reduction and internal fixation (ORIF). Medical records were reviewed for demographics, medical history, functional outcomes including quick Disabilities of the Arm, Shoulder, and Hand (qDASH), radiographs, and postoperative complications. Results There were 40 patients included for review. Average age was 84 years. The preoperative qDASH score was 69. At 6 months follow-up, the postoperative qDASH score was 13 (p < 0.001). There were five (12.5%) complications reported postoperatively. All fractures healed with adequate radiographic alignment and there were no hardware failures. Conclusion Distal radius fractures in patients older than 80 years treated with ORIF have good functional outcomes and low complication rates. Increased functionality and independence of the elderly, as well as updated implant design can lead to the effective surgical management of these patients. When indicated from a clinical perspective, operative fixation of distal radius fractures should be considered in patients older than 80 years.

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Probabilistic convergence transformation groups

Mathematica Slovaca ◽

10.1515/ms-2017-0194 ◽

2018 ◽

Vol 68 (6) ◽

pp. 1447-1464 ◽

Cited By ~ 1

Author(s):

T. M. G. Ahsanullah ◽

Gunther Jäger

Keyword(s):

Transformation Group ◽

Convergence Space ◽

Probabilistic Metric Space ◽

Arbitrary Group ◽

Convergence Group ◽

Group Of Homeomorphisms ◽

Convergence Structure ◽

Probabilistic Metric ◽

Probabilistic Convergence Space ◽

Natural Way

Abstract We introduce a notion of a probabilistic convergence transformation group, and present various natural examples including quotient probabilistic convergence transformation group. In doing so, we construct a probabilistic convergence structure on the group of homeomorphisms and look into a probabilistic convergence group that arises from probabilistic uniform convergence structure on function spaces. Given a probabilistic convergence space, and an arbitrary group, we construct a probabilistic convergence transformation group. Introducing a notion of a probabilistic metric convergence transformation group on a probabilistic metric space, we obtain in a natural way a probabilistic convergence transformation group.

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Transfacet screw placement for posterior fixation of C-7

Journal of Neurosurgery Spine ◽

10.3171/spi/2008/9/8/200 ◽

2008 ◽

Vol 9 (2) ◽

pp. 200-206 ◽

Cited By ~ 17

Author(s):

Eric M. Horn ◽

Nicholas Theodore ◽

Neil R. Crawford ◽

Nicholas C. Bambakidis ◽

Volker K. H. Sonntag

Keyword(s):

Intraoperative Complications ◽

Pedicle Screws ◽

Retrospective Chart Review ◽

Screw Placement ◽

Posterior Fixation ◽

Lateral Mass ◽

Screw Insertion ◽

Novel Technique ◽

Hardware Failures

Object Lateral mass screws are traditionally used to fixate the subaxial cervical spine, while pedicle screws are used in the thoracic spine. Lateral mass fixation at C-7 is challenging due to thin facets, and placing pedicle screws is difficult due to the narrow pedicles. The authors describe their clinical experience with a novel technique for transfacet screw placement for fixation at C-7. Methods A retrospective chart review was undertaken in all patients who underwent transfacet screw placement at C-7. The technique of screw insertion was the same for each patient. Polyaxial screws between 8- and 10-mm-long were used in each case and placed through the facet from a perpendicular orientation. Postoperative radiography and clinical follow-up were analyzed for aberrant screw placement or construct failure. Results Ten patients underwent C-7 transfacet screw placement between June 2006 and March 2007. In all but 1 patient screws were placed bilaterally, and the construct lengths ranged from C-3 to T-5. One patient with a unilateral screw had a prior facet fracture that precluded bilateral screw placement. There were no intraoperative complications or screw failures in these patients. After an average of 6 months of follow-up there were no hardware failures, and all patients showed excellent alignment. Conclusions The authors present the first clinical demonstration of a novel technique of posterior transfacet screw placement at C-7. These results provide evidence that this technique is safe to perform and adds stability to cervicothoracic fixation.

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