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Indian Journal of Plastic Surgery :... Feb 2023The axial vessels like the anterior and posterior tibial emerge as the first choice of recipient vessels, in free flaps for lower limb trauma. When the defects are...
The axial vessels like the anterior and posterior tibial emerge as the first choice of recipient vessels, in free flaps for lower limb trauma. When the defects are located more proximally in the leg, the deeper course of the axial vessels makes the dissection more tedious. Alternative vessels like the descending genicular, medial genicular, and distal end of the descending branch of the lateral circumflex femoral can be used for an end-to-end anastomosis, well away from the zone of trauma. The objective of this study was to define the indications and technique of the use of the sural vessels as the recipient pedicle for proximal and middle third leg defects. For the period 2006 to 2022, 18 leg defects following road traffic accidents were covered with latissimus dorsi muscle flap using sural vessels as the recipient pedicle. Among 18 patients, 8 patients had defect in proximal third, 8 had a combined defect in proximal and middle third leg, and 2 had defect in middle third leg. Two patients developed arterial thrombosis and one patient had venous thrombosis for which re-exploration was performed. Two flaps were lost and sixteen had successful wound coverage. The sural vessels as recipient pedicle are easier to access and can be considered as a reliable option for free flaps in limb defects of proximal and middle third leg. Using the submuscular part of the vessel ensures a better distal reach of the flap.
PubMed: 36998928
DOI: 10.1055/s-0042-1760094 -
Journal of Wrist Surgery Oct 2023The scaphotrapeziotrapezoidal (STT) joint transfers forces to the proximal carpal row from the thumb and fingers. Clinically, STT joint osteoarthritis is frequently...
The scaphotrapeziotrapezoidal (STT) joint transfers forces to the proximal carpal row from the thumb and fingers. Clinically, STT joint osteoarthritis is frequently observed on plain radiographs though its role in the mechanics of the wrist joint remains unclear. Our purpose was to use a model of normal wrist types, to predict STT motion upon load. Five normal computed tomography scans of a wrist type 1 and five wrist type 2 were used to model the wrist. A 200-N force was split and applied to the trapezoid and capitate to replicate forces during a knuckle pushup. The bony movement was predicted by the model as bony movement using finite element analysis. We found differences in force transfer through the STT joint between the two wrist types when loading the index and middle fingers. Type 1 wrists moved quantitatively more anterior-posterior, type 2 wrists moved more medially-laterally and more proximally-distally. The trapezium in type 1 wrists moved more in the coronal plane than in type 2 wrists. The trapezoid moved more from distal to proximal in a type 2 wrist, = 0.03. This study found differences in motion upon loading through the STT joint between type 1 and 2 wrists. Type 2 wrists moved more radially toward the proximal scaphoid and scapholunate ligament. This study may provide a mechanical basis for degenerative configurations. By linking observed patterns of degeneration to their mechanical causes we can aid in prevention of arthritis.
PubMed: 37841353
DOI: 10.1055/s-0043-1761287 -
Journal of B.U.ON. : Official Journal... 2014A considerable change in the anatomical distribution of colorectal cancer (CRC) towards more proximal sites has been observed in Western countries within the last 6-7... (Review)
Review
A considerable change in the anatomical distribution of colorectal cancer (CRC) towards more proximal sites has been observed in Western countries within the last 6-7 decades. As a result, tumors located proximally to the splenic flexure are now accounting for 30-40% (or even more) of overall CRC cases. This proximal migration is not always representing a true increase of proximal cancer, arising from various combinations of changes in the rates of proximal and distal cancer (e.g. proximal increase with distal stability/reduction, or decline in both sites albeit higher distally etc) in different areas and periods. Principal potential causes include ageing in Western populations (since proximal cancers are more common among the aged), various potentially site-specific exposures (lifestyle and medical) and systematic screening. Their effect is reflected in the particular shift patterns; for instance, widespread screening in USA has led to an overall CRC decline, more evident distally (for technical, anatomical and morphological reasons). Segmental disparities in particular characteristics (age, gender, morphology) and responses to various exposures are etiologically associated (for the most part) with underlying genetic differences between proximal and distal tumors. From clinical aspect, proximal shift necessitates a more generalized use of colonoscopy in screening programs. Potential interventions in treatment (segmental patient stratification) and prevention (identification of particular site-specific exposures) require further investigation.
Topics: Age Factors; Colorectal Neoplasms; Early Detection of Cancer; Genetic Predisposition to Disease; Humans; Life Style; Neoplasm Staging; Sex Factors
PubMed: 25261642
DOI: No ID Found -
Journal of Cerebral Blood Flow and... Jul 2012While it has been widely confirmed that cerebral blood flow is closely coupled with brain metabolism, it remains a matter of controversy whether capillary flow is... (Review)
Review
While it has been widely confirmed that cerebral blood flow is closely coupled with brain metabolism, it remains a matter of controversy whether capillary flow is directly controlled to meet the energy demands of the parenchyma. Since the capillary is known to lack smooth muscle cells, it has generally been considered that capillary flow is not regulated in situ. However, we now have increasing data supporting the physiological control of capillary flow. The observation of heterogeneity in the microcirculation in vivo has suggested that intravascular factors may be involved in the flow control, including non-Newtonian rheology, red blood cell flow, leukocyte adhesion, release of vasoactive mediators, and expression of glycoproteins on the endothelial cells. Astrocytes, a key mediator of the neurovascular unit, and intrinsic innervation may also regulate capillary flow. In addition, recent findings on pericyte contractility have attracted the attention of many researchers. Finally, based on these findings, we present a new model of flow control, the proximal integration model, in which localized neural activity is detected at nearby capillaries and the vasodilation signal is transmitted proximally along the vessel. Signals are then integrated at the precapillary arterioles and other arterioles further upstream and regulate the capillary flow.
Topics: Animals; Brain; Capillaries; Cerebrovascular Circulation; Hemodynamics; Humans; Models, Biological
PubMed: 22293984
DOI: 10.1038/jcbfm.2012.5 -
Injury Mar 2018In locked plate fixation of proximal humerus fractures, the calcar is an important anchor point for screws providing much-needed medial column support. Most locking...
INTRODUCTION
In locked plate fixation of proximal humerus fractures, the calcar is an important anchor point for screws providing much-needed medial column support. Most locking plate implants utilize a fixed-trajectory locking screw to achieve this goal. Consequently, adjustments of plate location to account for patient-specific anatomy may result in a screw position outside of the calcar. To date, little is known about the consequences of "missing" the calcar during plate positioning. This study sought to characterize the biomechanics associated with proximal and distal placement of locking plates in a two-part fracture model.
MATERIALS AND METHODS
This experiment was performed twice, first with elderly cadaveric specimens and again with osteoporotic sawbones. Two-part fractures were simulated and specimens were divided to represent proximal, neutral, and distal plate placements. Non-destructive torsional and axial compression tests were performed prior to an axial fatigue test and a ramp to failure. Torsional stiffness, axial stiffness, humeral head displacement and stiffness during fatigue testing, and ultimate load were compared between groups.
RESULTS
Cadavers: Proximal implant placement led to trends of decreased mechanical properties, but there were no significant differences found between groups. Sawbones: Distal placement increased torsional stiffness in both directions (p = 0.003, p = 0.034) and axial stiffness (p = 0.018) when compared to proximal placement. Distal placement also increased torsional stiffness in external rotation (p = 0.020), increased axial stiffness (p = 0.024), decreased humeral head displacement during fatigue testing, and increased stiffness during fatigue testing when compared to neutral placement.
DISCUSSION
The distal and neutral groups had similar mechanical properties in many cadaveric comparisons while the proximal group trended towards decreased construct stiffness.
RESULTS
from the Sawbones model were more definitive and provided further evidence that proximal calcar screw placements are undesirable and distal implant placement may provide improved construct stability.
CONCLUSION
Successful proximal humerus fracture reconstruction is inherent upon anatomic fracture reduction coupled with medial column support. Results from this experiment suggest that missing the calcar proximally is deleterious to fixation strength, while it is safe, and perhaps even desirable, to aim slightly distal to the intended target.
Topics: Aged; Aged, 80 and over; Biomechanical Phenomena; Bone Density; Bone Plates; Bone Screws; Bone Substitutes; Cadaver; Finite Element Analysis; Fracture Fixation, Internal; Humans; Materials Testing; Shoulder Fractures; Stress, Mechanical
PubMed: 29452734
DOI: 10.1016/j.injury.2018.02.007 -
North American Spine Society Journal Sep 2022Proximal junctional fractures (PJFr) can be a catastrophic complication associated with adult spinal deformity surgery. Osteoporosis can be a major risk factor for the...
BACKGROUND
Proximal junctional fractures (PJFr) can be a catastrophic complication associated with adult spinal deformity surgery. Osteoporosis can be a major risk factor for the cause of PJFr. Recent studies suggest using surrogate computed tomography (CT) scans in place of spinal dual-energy x-ray absorptiometry (DEXA) scores for bone mineral density (BMD). Investigate the feasibility of using preoperative CT based bone mineral density at upper instrumented vertebrae (UIV) and one level proximally (UIV+1) and distally (UIV-1) to predict the possibility of PJFr risk.
METHODS
Retrospective two-academic center case-controlled study, reviewed consecutive adult spinal deformity surgeries; included constructs encompassing at least five fusion levels and fusions to pelvis. Examined demographic, surgical, and radiographic data preoperatively, postoperatively, and final follow-up. Formed groups based on type of proximal junctional deformity (PJD): Control (no PJD), proximal junctional kyphosis (PJK) and PJFr. Preoperative CT BMD values measured in Hounsfield units (HU) for sagittal and axial planes at UIV, UIV+1, and UIV-1 and compared between groups.
RESULTS
N=92 patients. Preoperative CT scan BMD values were significantly lower in PJFr vs. control at: UIV+1 in sagittal (p=0.007), axial (p=0.02) planes; UIV sagittal (p=0.04) and axial (p=0.03) planes; and UIV-1 sagittal (p=0.05) plane. Similarly, lower CT scan BMD values noted in PJFr vs. PJK at: UIV+1 in sagittal (p=0.04) and axial (p=0.03) planes. Trend seen with lower CT scan BMD values at UIV+1 level in PJFr vs. PJK in sagittal (p=0.12) and axial (p=0.10) planes. Preoperative global sagittal imbalance measurements significantly lower in control, but comparable between PJK and PJFr.
CONCLUSIONS
Higher preoperative global sagittal imbalance with lower preoperative CT BMD values at UIV and UIV+1 vertebral body may increase the risk of proximal junctional fractures after adult spine deformity surgery. Proximal junctional hooks may supplement the pathogenesis. Readers should note the small sample size. 3.
PubMed: 35783005
DOI: 10.1016/j.xnsj.2022.100130 -
BJU International Jan 2017To describe a new hypothesis for the initial events leading to urinary stones. A biomechanical perspective on Randall's plaque formation through form and function... (Review)
Review
OBJECTIVES
To describe a new hypothesis for the initial events leading to urinary stones. A biomechanical perspective on Randall's plaque formation through form and function relationships is applied to functional units within the kidney, we have termed the 'medullo-papillary complex' - a dynamic relationship between intratubular and interstitial mineral aggregates.
METHODS
A complete MEDLINE search was performed to examine the existing literature on the anatomical and physiological relationships in the renal medulla and papilla. Sectioned human renal medulla with papilla from radical nephrectomy specimens were imaged using a high resolution micro X-ray computed tomography. The location, distribution, and density of mineral aggregates within the medullo-papillary complex were identified.
RESULTS
Mineral aggregates were seen proximally in all specimens within the outer medulla of the medullary complex and were intratubular. Distal interstitial mineralisation at the papillary tip corresponding to Randall's plaque was not seen until a threshold of proximal mineralisation was observed. Mineral density measurements suggest varied chemical compositions between the proximal intratubular (330 mg/cm ) and distal interstitial (270 mg/cm ) deposits. A review of the literature revealed distinct anatomical compartments and gradients across the medullo-papillary complex that supports the empirical observations that proximal mineralisation triggers distal Randall's plaque formation.
CONCLUSION
The early stone event is initiated by intratubular mineralisation of the renal medullary tissue leading to the interstitial mineralisation that is observed as Randall's plaque. We base this novel hypothesis on a multiscale biomechanics perspective involving form and function relationships, and empirical observations. Additional studies are needed to validate this hypothesis.
Topics: Calcinosis; Humans; Kidney Diseases; Kidney Medulla; Minerals; Urinary Calculi
PubMed: 27306864
DOI: 10.1111/bju.13555 -
Psychology of Addictive Behaviors :... Nov 2022Research and theory support alcohol use as a proximal antecedent to in-person partner abuse (PA). However, event-level research has not examined cyber PA thereby...
OBJECTIVE
Research and theory support alcohol use as a proximal antecedent to in-person partner abuse (PA). However, event-level research has not examined cyber PA thereby limiting our understanding of whether alcohol use proximally relates to cyber PA.
METHOD
We collected daily data on alcohol use and cyber PA from college students ( = 236; 73.3% women) for 60 consecutive days. Controlling for cyber PA victimization, we evaluated whether college students who consumed more drinks perpetrated more cyber PA (between-person effects), whether cyber PA was more likely to occur on days in which alcohol use was higher than each individual's average (within-person effect), and whether within- and between-person associations between alcohol use and cyber PA varied by sex.
RESULTS
Women were more likely than men to perpetrate cyber PA but there were no sex differences in the association between alcohol use and cyber PA. Multilevel modeling revealed that neither higher average alcohol use, nor drinking more than one usually does on a given day, associated with odds of subsequent cyber PA. Although alcohol use did not associate with odds of subsequent cyber PA, posthoc analyses revealed that odds of cyber PA increased as alcohol use increased, regardless of whether drinking occurred before or after cyber PA. Thus, alcohol use may have been more likely to occur after cyber PA.
CONCLUSIONS
Results did not support alcohol use as a proximal antecedent to college students' cyber PA. Future research should investigate of cyber PA as a proximal risk factor for subsequent alcohol use. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Topics: Male; Female; Humans; Spouse Abuse; Students; Interpersonal Relations; Risk Factors; Alcohol Drinking; Alcohol Drinking in College
PubMed: 35113587
DOI: 10.1037/adb0000818 -
La Pediatria Medica E Chirurgica :... Jun 2017The aim of this study was to verify the validity, feasibility, and the functional results, by uroflowmetry, of Tubularized proximallyincised plate technique in selected...
The aim of this study was to verify the validity, feasibility, and the functional results, by uroflowmetry, of Tubularized proximallyincised plate technique in selected case of distal/midshaft hypospadias. Out of 120 patients scheduled to undergo TIP (or Snodgrass) procedure, 23 were selected between January 2013 and January 2016 (19.1%). This case series comprised 16 patients with distal and 7 with midshaft hypospadias. Mean age at surgery was 2.9 years. The inclusion criteria were a deep and wide glandular groove and a proximal narrow urethral plate. The procedure was carried out as described by Snodgrass but the incision of the urethral plate, including the mucosal and submucosal tissue, was made only proximally, between the original meatus and the glandular groove in no case extending to the entire length of the plate. Postoperatively a foley catheter was left in place from 4 to 7 days. Uroflowmetry was performed when the patients age ranged from 2.5 to 5.7 years (mean age 3.11 years and mean follow-up 1.8 years, body surface 2). No patient presented fistulas nor perioperative complications. At uroflowmetry, eighteen patients presented values above the 25th percentile and 5 showed a borderline flow. All patients in this group remained stable without urinary symptoms. In selected cases, the tubularized proximally-incised plate yields satisfactory cosmetic and functional results for the treatment of midshaft proximal hypospadias. A long-term follow-up study is needed for further evaluation. Patient selection is crucial for the success of this technique.
Topics: Child, Preschool; Follow-Up Studies; Humans; Hypospadias; Infant; Male; Patient Selection; Treatment Outcome; Urethra; Urinary Catheterization; Urogenital Surgical Procedures
PubMed: 28673072
DOI: 10.4081/pmc.2017.151 -
Analysing debranching techniques in Frozen Elephant Trunk procedures: a narrative literature review.Cardiovascular Diagnosis and Therapy Apr 2023Since 2003, the Frozen Elephant Trunk (FET) technique has attained rising popularity for treating extensive aortic arch pathologies such as acute and chronic aortic... (Review)
Review
BACKGROUND AND OBJECTIVE
Since 2003, the Frozen Elephant Trunk (FET) technique has attained rising popularity for treating extensive aortic arch pathologies such as acute and chronic aortic dissection, as well as thoracic aortic aneurysm. Conventionally, the FET procedure included a complete resection of the aortic arch and, subsequently, a distal aortic anastomosis of the prosthetic part of the hybrid graft in arch zone 3. Simultaneous to the introduction of the FET technique, the traditional Elephant Trunk technique was simplified by adding debranching techniques which allows for proximalization of the distal aortic anastomosis. Nowadays, modern concepts of aortic arch surgery combine the FET technique with proximalization of the distal anastomosis in arch zone 2 or further proximal, achieved by using different debranching techniques. This review describes different debranching techniques to facilitate arch reconstruction, and aims to critically assess the outcomes and potential clinical advantages of proximalization using debranching in FET surgery.
METHODS
We conducted a search using the PubMed and Google Scholar electronic databases to evaluate published outcomes of different debranching techniques. An overview of the data synthesis of 21 included studies is reported.
KEY CONTENT AND FINDINGS
Most studies report numeric, but not statistically significant improved outcomes after debranching in FET surgery for mortality, neurological complications, spinal cord injury, kidney failure, bowel ischemia and recurrent nerve palsy. Some studies report statistically significant improved results in isolated endpoints such as neurological, bowel ischemia, and recurrent nerve palsy. Most studies report debranching to be technically easier, but this is difficult to objectively assess and measure.
CONCLUSIONS
There is an improved numeric outcome of different debranching techniques with proximalization of the distal anastomosis, but without reaching statistical significance. This review shows marked heterogeneity across included studies and highlights the scarce use of existing guidelines in clinical research of open aortic arch surgery as proposed by the International Aortic Arch Surgery Study Group. Furthermore, this review demonstrates the urgent need for multicenter registries or studies to be able to compare the outcome of different surgical techniques for various aortic arch pathologies.
PubMed: 37583690
DOI: 10.21037/cdt-22-502