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Sanders AP, Swerdlow NJ, Jabbour G, Schermerhorn ML. The effect of Fiber Optic RealShape technology on the reduction of radiation during complex endovascular surgery. J Vasc Surg 2024; 79:954-961. [PMID: 37931886 PMCID: PMC10960673 DOI: 10.1016/j.jvs.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/08/2023]
Abstract
OBJECTIVE Despite the advantages that fenestrated endovascular aortic repair has over open repair, it is accompanied by the consequence of radiation exposure, which can result in long-term complications for both the patient and surgical staff. Fiber Optic RealShape (FORS) technology is a novel advancement that uses emitted light from a fiber optic wire and enables the surgeon to cannulate vessels in real time without live fluoroscopy. This technology has been implemented at select centers to study its effectiveness for cannulation of target vessels and its impact on procedural radiation. METHODS We collected prospective data on physician-modified endograft (PMEG) cases before and after the introduction of FORS technology. FORS PMEGs were matched with up to three conventional fluoroscopy cases by number of target vessels, inclusion of a bifurcated device below, aneurysm extent, and patient body mass index. The procedural radiation parameters were compared between these cohorts. Within the FORS cohort, we analyzed the rate of successful target vessel cannulation for all cases done with this technology (including cases other than PMEGs), and we compared the radiation between the cannulations using only FORS with those that abandoned FORS for conventional fluoroscopy. RESULTS Nineteen FORS PMEGs were able to be matched to 45 conventional fluoroscopy cases. Procedures that used FORS technology had significantly reduced total air kerma (527 mGy vs 964 mGy), dose area product (121 Gy∗cm2 vs 186 Gy∗cm2), fluoroscopy dose (72.1 Gy∗cm2 vs 132.5 Gy∗cm2), and fluoroscopy time (45 minutes vs 72 minutes). There was no difference in procedure length, total contrast, or digital subtraction angiography. Within FORS cases, 66% of cannulations were completed using only FORS. Cannulations using only FORS had significant reduction of navigation air kerma (5.0 mGy vs 26.5 mGy), dose area product (1.2 Gy∗cm2 vs 5.1 Gy∗cm2), and fluoroscopy time (0.6 minutes vs 2.3 minutes) compared with cannulations abandoning FORS for conventional fluoroscopy. CONCLUSIONS This study demonstrates the advantages of FORS for total procedural radiation as well as during individual cannulation tasks. The implementation of FORS for target vessel catheterization has the potential to decrease the total degree of radiation exposure for the patient and surgical staff during complex endovascular aortic surgeries.
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Affiliation(s)
- Andrew P Sanders
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Nicholas J Swerdlow
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Surgery, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Gabriel Jabbour
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Marc L Schermerhorn
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
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Jabbour G, Yadavalli SD, Straus S, Sanders AP, Rastogi V, Eldrup-Jorgensen J, Powell RJ, Davis RB, Schermerhorn ML. Learning curve of transfemoral carotid artery stenting in the vascular quality initiative registry. J Vasc Surg 2024:S0741-5214(24)00403-8. [PMID: 38428653 DOI: 10.1016/j.jvs.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 03/03/2024]
Abstract
OBJECTIVE With the recent expansion of the Centers for Medicare and Medicaid Services coverage, transfemoral carotid artery stenting (tfCAS) is expected to play a larger role in the management of carotid disease. Existing research on the tfCAS learning curve, primarily conducted over a decade ago, may not adequately describe the current effect of physician experience on outcomes. Because approximately 30% of perioperative strokes/deaths post-CAS occur after discharge, appropriate thresholds for in-hospital event rates have been suggested to be <4% for symptomatic and <2% for asymptomatic patients. This study evaluates the tfCAS learning curve using Vascular Quality Initiative (VQI) data. METHODS We identified VQI patients who underwent tfCAS between 2005 and 2023. Each physician's procedures were chronologically grouped into 12 categories, from procedure counts 1-25 to 351+. The primary outcome was in-hospital stroke/death rate; secondary outcomes were in-hospital stroke/death/myocardial infarction (MI), 30-day mortality, in-hospital stroke/transient ischemic attack (stroke/TIA), and access site complications. The relationship between outcomes and procedure counts was analyzed using the Cochran-Armitage test and a generalized linear model with restricted cubic splines. Our results were then validated using a generalized estimating equations model to account for the variability between physicians. RESULTS We analyzed 43,147 procedures by 2476 physicians. In symptomatic patients, there was a decrease in rates of in-hospital stroke/death (procedure counts 1-25 to 351+: 5.2%-1.7%), in-hospital stroke/death/MI (5.8%-1.7%), 30-day mortality (4.6%-2.8%), in-hospital stroke/TIA (5.0%-1.1%), and access site complications (4.1%-1.1%) as physician experience increased (all P values < .05). The in-hospital stroke/death rate remained above 4% until 235 procedures. Similarly, in asymptomatic patients, there was a decrease in rates of in-hospital stroke/death (2.1%-1.6%), in-hospital stroke/death/MI (2.6%-1.6%), 30-day mortality (1.7%-0.4%), and in-hospital stroke/TIA (2.8%-1.6%) with increasing physician experience (all P values <.05). The in-hospital stroke/death rate remained above 2% until 13 procedures. CONCLUSIONS In-hospital stroke/death and 30-day mortality rates after tfCAS decreased with increasing physician experience, showing a lengthy learning curve consistent with previous reports. Given that physicians' early cases may not be included in the VQI, the learning curve was likely underestimated. Nevertheless, a substantially high rate of in-hospital stroke/death was found in physicians' first 25 procedures. With the recent Centers for Medicare and Medicaid Services coverage expansion for tfCAS, a significant number of physicians would enter the early stage of the learning curve, potentially leading to increased postoperative complications.
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Affiliation(s)
- Gabriel Jabbour
- Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Sai Divya Yadavalli
- Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Sabrina Straus
- Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Andrew P Sanders
- Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Vinamr Rastogi
- Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jens Eldrup-Jorgensen
- Division of Vascular Surgery, Maine Medical Center, Tufts University School of Medicine, Portland, ME
| | - Richard J Powell
- Department of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH
| | - Roger B Davis
- Division of General Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Marc L Schermerhorn
- Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
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Sanders AP, Vosburg RW. Early postoperative COVID infection is associated with significantly increased risk of venous thromboembolism after metabolic and bariatric surgery. Surg Obes Relat Dis 2024:S1550-7289(24)00046-7. [PMID: 38556419 DOI: 10.1016/j.soard.2024.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/11/2023] [Accepted: 01/28/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND Patients who undergo metabolic and bariatric surgery (MBS) are at risk for thromboembolism. Patients are susceptible to coronavirus throughout the perioperative period, which also has a well-known association with thrombotic complications. OBJECTIVES To identify and define the association between venous thromboembolism (VTE) and postoperative coronavirus diagnosis in bariatric surgery patients. SETTING United States. METHODS We conducted a retrospective cohort study using the MBS Accreditation and Quality Improvement Program (MBSAQIP) 2021 database to analyze the incidence of VTE within 30 days of surgery. VTE was a composite variable defined as either postoperative pulmonary embolism or postoperative venous thrombus requiring treatment. Cohorts were stratified by whether the patient was diagnosed with postoperative coronavirus. We created a multivariable logistic regression model to determine the adjusted odds of postoperative VTE based on various factors. Additionally, we conducted subset analyses of sleeve gastrectomy and Roux-en-Y bypass cases, the 2 most frequent bariatric operations in the United States. RESULTS Patients diagnosed with postoperative coronavirus were significantly more likely to develop postoperative VTE (1.1% versus .3%, P < .001). In our logistic regression model, the adjusted odds of postoperative VTE for patients with postoperative coronavirus was 3.55 (95% CI: 2.15-5.87, P < .001). For patients who underwent Roux-en-Y bypass, the adjusted odds was even greater at 5.69 (95% CI: 2.76-11.70, P < .001). CONCLUSIONS Early postoperative coronavirus infection after MBS is associated with higher odds of postoperative VTE. This persisted on subset analyses of the 2 most common procedures and appeared particularly important for Roux-en-Y bypass. COVID infection after MBS may warrant prolonged VTE prophylaxis.
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Affiliation(s)
- Andrew P Sanders
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - R Wesley Vosburg
- Department of Surgery, Mount Auburn Hospital, Harvard Medical School, Cambridge, Massachusetts.
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Sanders AP, Swerdlow NJ, Yadavalli SD, Marcaccio CL, Stangenberg L, Schermerhorn ML. Reinterventions and sac dynamics after fenestrated endovascular aortic repair with physician-modified endografts for index aneurysm repair and following proximal failure of prior endovascular aortic repair. J Vasc Surg 2024:S0741-5214(24)00005-3. [PMID: 38185213 DOI: 10.1016/j.jvs.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 01/09/2024]
Abstract
OBJECTIVE The high frequency of reinterventions after fenestrated endovascular aortic repair (FEVAR) with physician-modified endografts (PMEGs) has been well-studied. However, the impact of prior EVAR on reinterventions and sac behavior following these procedures remains unknown. We analyzed 3-year rates of reinterventions and sac dynamics following PMEG for index aneurysm repair compared with PMEG for prior EVAR with loss of proximal seal. METHODS We performed a retrospective analysis of 122 consecutive FEVARs with PMEGs at a tertiary care center submitted to the United States Food and Drug Administration in support of an investigational device exemption trial. We excluded patients with aortic dissection (n = 5), type I to III thoracoabdominal aneurysms (n = 13), non-elective procedures (n = 4), and prior aortic surgery other than EVAR (n = 8), for a final cohort of 92 patients. Patients were divided into those who underwent PMEG for index aneurysm repair (primary FEVAR) and those who underwent PMEG for rescue of prior EVAR with loss of proximal seal (secondary FEVAR). The primary outcomes were freedom from reintervention and sac dynamics (regression as ≥5 mm decrease, expansion as ≥5 mm increase, and stability as <5 mm increase or decrease) at 3 years. Secondary outcomes were perioperative mortality and 3-year survival. RESULTS Of the 92 patients included, 56 (61%) underwent primary FEVAR and 36 (39%) underwent secondary FEVAR. Secondary FEVAR patients were older (78 years [interquartile range (IQR), 74.5-83.5 years] vs 73 years [IQR, 69-78.5 years]; P < .001), more frequently male (86% vs 68%; P = .048), and had larger aneurysms (72.5 mm [IQR, 65.5-81 mm] vs 59 mm [IQR, 55-65 mm]; P < .001). Perioperative mortality was 1.8% for primary FEVAR and 2.7% for secondary FEVAR (P = .75). At 3 years, overall survival was 84% for primary FEVAR and 71% for secondary FEVAR (P = .086). Freedom-from reintervention was significantly higher for primary FEVAR than secondary FEVAR, specifically 82% vs 38% at 3 years (P < .001). Primary FEVAR also had more desirable sac dynamics relative to secondary FEVAR at 3 years (primary: 54% stable, 46% regressed, 0% expanded vs secondary: 33% stable, 28% regressed, and 39% expanded; P = .038). CONCLUSIONS FEVAR for primary aortic repair and FEVAR for rescue of prior EVAR with loss of proximal seal are two distinct entities. Following primary FEVAR, less than a quarter of patients have undergone reintervention at 3 years, and sac expansion was not seen in our cohort. Comparatively, 3 years after secondary FEVAR, over one-half of patients have undergone reintervention and over one-third have had ongoing sac expansion. Vigilant surveillance and a low threshold for further interventions are crucial following secondary FEVAR.
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Affiliation(s)
- Andrew P Sanders
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston
| | - Nicholas J Swerdlow
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston
| | - Sai Divya Yadavalli
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston
| | - Christina L Marcaccio
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston
| | - Lars Stangenberg
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston
| | - Marc L Schermerhorn
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston.
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Jabbour G, Yadavalli SD, Strauss S, Sanders AP, Rastogi V, Eldrup-Jorgensen J, Powell RJ, Davis RB, Schermerhorn ML. Impact of Physician Experience on Stroke or Death Rates in Transfemoral Carotid Artery Stenting: Insights from the Vascular Quality Initiative. medRxiv 2023:2023.11.16.23298660. [PMID: 38014117 PMCID: PMC10680887 DOI: 10.1101/2023.11.16.23298660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Objective With the recent expansion of the Centers for Medicare and Medicaid Services (CMS) coverage, transfemoral carotid artery stenting (tfCAS) is expected to play a larger role in the management of carotid disease. Existing research on the tfCAS learning curve, primarily conducted over a decade ago, may not adequately describe the current effect of physician experience on outcomes. This study evaluates the tfCAS learning curve using VQI data. Methods We analyzed tfCAS patient data from 2005-2023. Each physician's procedures were chronologically grouped into 12 categories, from procedure counts 1-25 to 351+. Primary outcome was in-hospital stroke/death rate; secondary outcomes were in-hospital stroke/death/MI, 30-day mortality, and in-hospital stroke/TIA. The relationship between outcomes and procedure counts was analyzed using Cochran Armitage test and a generalized linear model with restricted cubic splines, validated using generalized estimating equations. Results We analyzed 43,147 procedures by 2,476 physicians. In symptomatic patients, there was a decrease in rates of in-hospital stroke/death (procedure counts 1-25 to 351+: 5.2% to 1.7%), in-hospital stroke/death/MI (5.8% to 1.7%), 30-day mortality (4.6% to 2.8%), in-hospital stroke/TIA (5.0% to 1.1%) (all p-values<0.05). The in-hospital stroke/death rate remained above 4% until 235 procedures. Similarly, in asymptomatic patients, there was a decrease in rates of in-hospital stroke/death (2.1% to 1.6%), in-hospital stroke/death/MI (2.6% to 1.6%), 30-day mortality (1.7% to 0.4%), and in-hospital stroke/TIA (2.8% to 1.6%) with increasing physician experience (all p-values<0.05). The in-hospital stroke/death rate remained above 2% until 13 procedures. Conclusions In-hospital stroke/death and 30-day mortality rates post-tfCAS decreased with increasing physician experience, showing a lengthy learning curve consistent with previous reports. Given that physicians' early cases may not be included in the VQI, the learning curve was likely underestimated. With the recent CMS coverage expansion for tfCAS, a significant number of physicians would enter the early stage of the learning curve, potentially leading to increased post-operative complications.
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Affiliation(s)
- Gabriel Jabbour
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sai Divya Yadavalli
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sabrina Strauss
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Andrew P. Sanders
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Vinamr Rastogi
- Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Jens Eldrup-Jorgensen
- Maine Medical Center, Division of Vascular Surgery, Tufts University School of Medicine, Portland, Me
| | - Richard J. Powell
- Department of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH
| | - Roger B. Davis
- Department of Medicine, Division of General Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Marc L. Schermerhorn
- Department of Surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Warshafsky C, Chaikof M, Sanders AP, Murji A, Sobel M, Hartman A, Huszti E, Li Q, Stere A. Preventing Isthmocele after Cesarean Section (PICS): A Pilot Randomized Controlled Trial. J Minim Invasive Gynecol 2021. [DOI: 10.1016/j.jmig.2021.09.492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zakhari A, Sanders AP, Murji A. Approach to Uterine Artery Occlusion at Myomectomy. J Minim Invasive Gynecol 2019. [DOI: 10.1016/j.jmig.2019.09.740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sanders AP, Kives SL, Allen LM. Creation of a Neovagina: A Modified Davydov Approach. J Minim Invasive Gynecol 2019. [DOI: 10.1016/j.jmig.2019.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Guldemond NA, Leffers P, Schaper NC, Sanders AP, Nieman F, Willems P, Walenkamp GHIM. The effects of insole configurations on forefoot plantar pressure and walking convenience in diabetic patients with neuropathic feet. Clin Biomech (Bristol, Avon) 2007; 22:81-7. [PMID: 17046124 DOI: 10.1016/j.clinbiomech.2006.08.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 08/17/2006] [Accepted: 08/21/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study was to evaluate the effects of insole configurations on plantar pressures and on walking convenience in patients with diabetic neuropathy. METHODS Twelve different insole configurations were constructed for each of 20 patients with diabetic neuropathy. For this, different combinations of a metatarsal dome, varus and valgus wedges and arch supports with different heights were added on a fitted basic insole. Foot orthoses were evaluated while patients walked on a treadmill. Plantar pressure was measured with a Pedar Insole-system. Walking convenience was scored on a 10-point scale. FINDINGS For the central and medial regions, plantar pressure reductions (up to 36% and 39%, respectively) were found when using a dome, standard and extra supports. The largest reductions were achieved with combination of a dome and extra support. There were no statistically significant pressure reducing effects of the insole configurations in the big toe and lateral regions, except for the effect of the combination extra support/varus wedge (21%), and for a dome (10%), respectively. The basic insole and a standard support received the best ratings for walking convenience and gradually worsened by adding extra support, a varus wedge and a dome. INTERPRETATION A dome and the supports reduce plantar pressure in the central and medial forefoot. The combination of a dome and extra support seems to be the best choice for the construction of insoles. The results of this study are a step towards developing an evidence-based algorithm for the construction of optimal orthoses in therapeutic shoe design.
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Affiliation(s)
- N A Guldemond
- Orthopedic Surgery, University Hospital Maastricht, The Netherlands.
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Sanders AP. In memoriam: Frans Verdoorn, bryologist, publisher and biohistorian. Janus 2001; 71:165-79. [PMID: 11620659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Ochoa JA, Sanders AP, Kiesler TW, Heck DA, Toombs JP, Brandt KD, Hillberry BM. In vivo observations of hydraulic stiffening in the canine femoral head. J Biomech Eng 1997; 119:103-8. [PMID: 9083856 DOI: 10.1115/1.2796051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The role that intertrabecular contents and their boundary conditions have on the dynamic mechanical response of canine femoral heads was investigated in vivo. Femoral heads from paired intact hind limbs of canine specimens were subjected to a sinusoidal strain excitation at physiologic frequencies, in the cranio-caudal direction. The fluid boundary conditions for the contralateral limbs were changed by predrilling through the lateral femoral cortex and into the femoral neck. The drilling procedure did not invade the head itself. This femoral head fluid boundary alteration reduced the stiffness by 19 percent for testing at 1 Hz. The results of this study demonstrate that fluid stiffening occurs in vivo as previously observed ex vivo.
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Affiliation(s)
- J A Ochoa
- Johnson & Johnson Professional, Raynham, MA 02767, USA
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Abstract
On the basis of a biomechanical model the present study investigates whether a foot-widening effect, which may result in recurrence of bunions, can be demonstrated in operated patients. Therefore, the medial deviation of the first metatarsal head as a result of flexion forces on the hallux was measured in eight patients with clinical idiopathic hallux valgus, who underwent a modified Hohmann osteotomy, and in eight "normal" persons. We found that (1) before osteotomy, all forefeet broadened while pressing the big toe downward, and (2) after surgery, widening of the forefeet on average had significantly diminished, but still existed, which might explain the development of recurrences. (3) After surgery, the patients showed a slight, but statistically nonsignificant, decrease (from 37 N to 25 N) of the isometrically determined average maximal applicable flexion force. These abnormal hallux loads may cause, or result from, a deviation in gait pattern.
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Affiliation(s)
- A P Sanders
- Department of Biomedical Physics and Technology, Faculty of Medicine and Applied Health Sciences, Erasmus University Rotterdam, The Netherlands
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Abstract
Several questions with regard to the hallux valgus complex, which includes metatarsus primus varus, give rise to discussion. How do bunions develop? Is disturbed muscle balance at the first metatarsophalangeal joint important in the pathogenesis of the hallux valgus complex? What is the relation between dynamic plantar load distribution and pain in the ball of the foot? What is the cause of recurrences of deformity after surgery? To answer these questions, we started with the biomechanical model of Snijders et al., which states that contraction of flexor muscles of the hallux worsens its valgus angle and causes medial deviation of the first metatarsal head. The present study was designed to validate the model on patients. When pressing the hallux downward, simultaneously the force under the toe and the medial deviation of the first metatarsal head were measured on preoperative patients and on controls (35 subjects in all). We could demonstrate with statistical significance that (1) when the subjects with hallux valgus push the great toe on the ground, the first metatarsal head moved in medial direction; in other words the foot widened. In the controls, as an average, the foot became narrower. (2) The greater the valgus deviation of the hallux, the greater the effect of the toe flexors, and (3) the greater the valgus deviation of the hallux, the less maximal flexion force it can apply. Implications of these findings on conservative and surgical therapy are discussed. The recurrences of deformity after first metatarsal osteotomies are explained by the action of the hallux flexors.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A P Sanders
- Department of Biomedical Physics and Technology, Faculty of Medicine and Applied Health Sciences, Erasmus University Rotterdam, The Netherlands
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Abstract
The mechanical properties of cancellous bone, as measured from bone plug samples have been widely documented. However, few tests have been attempted to explore the effects the intertrabecular contents may have on the load bearing capabilities. In this study, canine femoral heads were subjected to dynamic compressive strain cycles. The femoral heads were tested intact, as well as with disrupted boundary conditions of the continuous, intraosseous fluid space. A significant reduction in mechanical stiffness was observed when the fluid compartment boundary was disrupted by drilling a hole part way into the femoral neck. A finite element model of a typical femoral head showed that the stiffness change was not due to removal of material from the neck, hydraulic effects notwithstanding. Refilling the hole in the neck with saline solution and sealing the boundary restored the stiffness to the intact baseline level. However, an increase in the fluid pressure did not cause a statistically significant increase in the stiffness of the femoral head.
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Affiliation(s)
- J A Ochoa
- Indiana University School of Medicine, Indianapolis
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Sanders AP. [Flatfoot in children]. Ned Tijdschr Geneeskd 1989; 133:1469. [PMID: 2797246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Sanders AP, Joines WT, Allis JW. Effects of continuous-wave, pulsed, and sinusoidal-amplitude-modulated microwaves on brain energy metabolism. Bioelectromagnetics 1985; 6:89-97. [PMID: 3977971 DOI: 10.1002/bem.2250060109] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A comparison of the effects of continuous-wave, sinusoidal-amplitude-modulated, and pulsed square-wave-modulated 591-MHz microwave exposures on brain energy metabolism was made in male Sprague-Dawley rats (175-225 g). Brain NADH fluorescence, adenosine triphosphate (ATP) concentration, and creatine phosphate (CP) concentration were determined as a function of modulation frequency. Brain temperatures of animals were maintained between -0.1 and -0.4 degrees C from the preexposure temperature when subjected to as much as 20 mW/cm2 (average power) CW, pulsed, or sinusoidal-amplitude modulated 591-MHz radiation for 5 min. Sinusoidal-amplitude-modulated exposures at 16-24 Hz showed a trend toward preferential modulation frequency response in inducing an increase in brain NADH fluorescence. The pulse-modulated and sinusoidal-amplitude-modulated (16 Hz) microwaves were not significantly different from CW exposures in inducing increased brain NADH fluorescence and decreased ATP and CP concentrations. When the pulse-modulation frequency was decreased from 500 to 250 pulses per second the average incident power density threshold for inducing an increase in brain NADH fluorescence increased by a factor of 4--ie, from about 0.45 to about 1.85 mW/cm2. Since brain temperature did not increase, the microwave-induced increase in brain NADH and decrease in ATP and CP concentrations was not due to hyperthermia. This suggests a direct interaction mechanism and is consistent with the hypothesis of microwave inhibition of mitochondrial electron transport chain function of ATP production.
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Abstract
The effects of hyperthermia, alone and in conjunction with microwave exposure, on brain energetics were studied in anesthetized male Sprague-Dawley rats. The effect of temperature on adenosine triphosphate concentration [ATP] and creatine phosphate concentration [CP] was determined in the brains of rats that were maintained at 35.6, 37.0, 39.0, and 41.0 degrees C. At 37, 39, and 41 degrees C brain [ATP] and [CP] were down 6.0, 10.8, and 29.2%, and 19.6, 28.7, and 44%, respectively, from the 35.6 degrees C control concentrations. Exposure of the brain to 591-MHz radiation at 13.8 mW/cm2 for 0.5, 1.0, 3.0, and 5.0 min caused further decreases (below those observed for 30 degrees C hyperthermia only) of 16.0, 29.8, 22.5, and 12.3% in brain [ATP], and of 15.6, 25.1, 21.4, and 25.9% in brain [CP] after 0.5, 1.0, 3.0, and 5.0 min, respectively. Recording of brain reduced nicotinamide adenine dinucleotide (NADH) fluorescence before, during, and after microwave exposure showed an increase in NADH fluorescence during microwave exposure that returned to preexposure levels within 1 min postexposure. Continuous recording of brain temperatures during microwave exposures showed that brain temperature varied between -0.1 and +0.05 degrees C. Since the microwave exposures did not induce tissue hyperthermia, it is concluded that direct microwave interaction at the subcellular level is responsible for the observed decrease in [ATP] and [CP].
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Abstract
Three key compounds in brain energy metabolism have been measured during and after exposure to continuous wave radiofrequency radiation at 200, 591, and 2,450 MHz. Frequency-dependent changes have been found for all three compounds. Changes in NADH fluorescence have been measured on the surface of a surgically uncovered rat brain during exposure. At 200 and 591 MHz, NADH fluorescence increased in a dose-dependent manner between approximately 1 and 10 mW/cm2, then became constant at higher exposures. There was no effect at 2,450 MHz. Levels of ATP and CP were measured in whole brain after exposure. The ATP levels were decreased at 200 and 591 MHz but not at 2,450 MHz. The CP levels decreased only at 591 MHz. The effect of duration of exposure (up to 5 min) was investigated for all compounds at 200 MHz and 2,450 MHz, and exposures to 20 minutes were examined at 591 MHz. Temperature in the rat brain was essentially constant for all exposures. A general mechanism for inhibition of the mitochondrial electron transport chain and the CP-kinase reaction pathway by radiofrequency radiation has been proposed.
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Abstract
The initiating factor in ARDS is a matter of controversy. Some investigators relate ARDS development to diffuse pulmonary microemboli after stress ranging from sepsis to non-thoracic and thoracic trauma. Others indicate hyperoxic exposure as the causative agent. This investigation looked for a common factor in ischemia and hyperoxic exposure in lung which could cause the genesis of ARDS. Studies of oxidative phosphorylation, succinate dehydrogenase activity and ATP level were performed on ischemic and 100% O2 exposed lung. Results in both showed decreased respiration rate below the basal rate, decreased SDH activity, followed by marked decrease in ATP levels in pulmonary tissue. Decrease in respiration (ATP production) capacity and ATP levels in ischemic lung were such that normal cell functions could not be sustained if returned to normal circulation. Hyperbaric O2 therapy would subsequently decrease energy metabolism in regions of normal circulation and in previously ischemic regions.
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Abstract
Rat brain was exposed to 591-MHz, continuous-wave (CW) microwaves at 13.8 or 5.0 mW/cm2 to determine the effect on nicotinamide adenine dinucleotide, reduced (NADH), adenosine triphosphate (ATP) and creatine phosphate (CP) levels. On initiation of the in vivo microwave exposures, fluorimetrically determined NADH rapidly increased to a maximum of 4.0%-12.5% above pre-exposure control levels at one-half minute, than decreased slowly to 2% above control at three minutes, finally increasing slowly to 5% above control level at five minutes. ATP and CP assays were performed on sham- and microwave-exposed brain at each exposure time. At 13.8 mW/cm2, brain CP level was decreased an average of 39.4%, 41.1%, 18.2%, 13.1%, and 36.4% of control at exposure points one-half, one, two three, and five minutes, respectively, and brain ATP concentration was decreased an average of 25.2%, 15.2%, 17.8%, 7.4%, and 11.2% of control at the corresponding exposure periods. ATP and CP levels of rat brain exposed to 591-MHz cw microwaves at 5mW/cm2 for one-half and one minute were decreased significantly below control levels at these exposure times, but were not significantly different from the 13.8 mW/cm2 exposures. For all exposures, rectal temperature remained constant. Heat loss through the skull aperture caused brain temperature to decrease during the five-minute exposures. This decrease was the same in magnitude for experimental and control subjects. Changes in NADH, ATP, and CP levels during microwave exposure cannot be attributed to general tissue hyperthermia. The data support the hypothesis that microwave exposure inhibits mitochondrial electron transport chain function, which results in decreased ATP and CP levels in brain.
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Pratt PC, Sanders AP, Currie WD. Oxygen toxicity and gas mixtures: morphology. Chest 1974; 66:8S-9S. [PMID: 4834931 DOI: 10.1378/chest.66.1_supplement.8s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Currie WD, Gelein RM, Sanders AP. Comparison of protective agents against hyperbaric oxygen in large animals. Aerosp Med 1973; 44:996-8. [PMID: 4744258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Sanders AP. 131 I-triolein absorption test. J Nucl Med 1973; 14:300-1. [PMID: 4698334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Sanders AP, Gelien RM, Kramer RS, Currie WD. Protection against the chronic effects of hyperbaric oxygen toxicity by succinate and reduced glutathione. Aerosp Med 1972; 43:533-6. [PMID: 5024260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Currie WD, Kramer RS, Sanders AP. Effects of hyperbaric oxygenation of metabolism. VII. Succinate protection against oxygen toxicity in large animals. Proc Soc Exp Biol Med 1971; 136:630-1. [PMID: 5544509 DOI: 10.3181/00379727-136-35328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Abstract
✓ Consecutive studies of brain energetics undertaken at Duke University during a period of 5 years are described. Various forms of stress such as hypoxia, hyperbaric oxygenation, and selected drugs were used to depict quantitative adverse effects upon the brain's basic energy system, and protectant measures evaluated including hypothermia and appropriate substrates. A systematic survey of substrate protectants was carried out in laboratory animals, and the theory and practice of preserving brain energy levels explored. A foundation for clinical application has been established.
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Abstract
The concentration of adenosine triphosphate in the brain decreased before the onset of generalized convulsions in unanesthetized rats subjected to acute hypoxia or treated with hydroxylamine or pentylenetetrazole (Metrazol). As the convulsive episode continued, adenosine triphosphate decreased further. Stimulation of adenosine triphosphate production forestalled its disappearance from the brain and delayed the development of seizure activity.
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Currie WD, Gelein RM, Sanders AP. Effects of hyperbaric oxygenation on metabolism. VI. Efficacy of protective agents at 5,7,9, and 11 atmospheres of 100 percent oxygen. Proc Soc Exp Biol Med 1970; 133:103-5. [PMID: 4312711 DOI: 10.3181/00379727-133-34417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Currie WD, Gelein RM, Sanders AP. Effects of hyperbaric oxygenation on metabolism. V. Comparison on protective agents at 5 atmospheres 100 per cent oxygen. Proc Soc Exp Biol Med 1969; 132:660-2. [PMID: 5355123 DOI: 10.3181/00379727-132-34282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Sanders AP, Currie WD, Woodhall B. Protection of brain metabolism with glutathione, glutamate, gamma-aminobutyrate and succinate. Proc Soc Exp Biol Med 1969; 130:1021-7. [PMID: 5773654 DOI: 10.3181/00379727-130-33713] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Kramer RS, Sanders AP, Lesage AM, Woodhall B, Sealy WC. The effect profound hypothermia on preservation of cerebral ATP content during circulatory arrest. J Thorac Cardiovasc Surg 1968; 56:699-709. [PMID: 5697463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Sanders AP, Lester RG, Woodhall B. Hyperbaric oxygen toxicity prevention with succinate. JAMA 1968; 204:241-6. [PMID: 5694557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Sanders AP, Hall IH. Effects of Hyperbaric Oxygenation on Metabolism. IV. Time Sequence of Biochemical Changes at 5 Atmospheres 100% Oxygen. Exp Biol Med (Maywood) 1967; 125:716-21. [PMID: 15938249 DOI: 10.3181/00379727-125-32188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Baylin GJ, DeMaria WJ, Baylin SB, Krueger RP, Sanders AP. ATP concentration and localization of sites of epinephrine induced renal artery constriction. Proc Soc Exp Biol Med 1966; 122:396-9. [PMID: 5980544 DOI: 10.3181/00379727-122-31144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Hall IH, Sanders AP. Effects of hyperbaric oxygenation on metabolism. 3. Succinic dehydrogenase, acid phosphatase, cathepsin and soluble nitrogen. Proc Soc Exp Biol Med 1966; 121:1203-6. [PMID: 5937727 DOI: 10.3181/00379727-121-31005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Sanders AP, Hall IH, Cavanaugh PJ, Woodhall B. Effects of hyperbaric oxygenation on metabolism. I. ATP concentration in rat brain, liver and kidney. Proc Soc Exp Biol Med 1966; 121:32-4. [PMID: 5902951 DOI: 10.3181/00379727-121-30689] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Sanders AP, Hall IH. Effects of hyperbaric oxygenation metabolism. II. Oxidative phosphorylation in rat brain, liver and kidney. Proc Soc Exp Biol Med 1966; 121:34-6. [PMID: 5902952 DOI: 10.3181/00379727-121-30690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Abstract
When succinate is used to protect rats against the toxicity of oxygen at high pressure, 100 percent survive, with normal or above normal concentrations of adenosine triphosphate being present in the cerebral hemisphere, liver, and kidney. In contrast, 90 percent of the nonprotected animals died during exposure. In corresponding tissues of surviving nonprotected animals adenosine triphosphate concentrations are markedly reduced.
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