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Featured researches published by Patrick Knott.


Scoliosis | 2012

2011 SOSORT guidelines: Orthopaedic and Rehabilitation treatment of idiopathic scoliosis during growth

Stefano Negrini; Angelo Gabriele Aulisa; Lorenzo Aulisa; Alin B Circo; Jean Claude de Mauroy; Jacek Durmała; Theodoros B Grivas; Patrick Knott; Tomasz Kotwicki; Toru Maruyama; Silvia Minozzi; Joseph P O'Brien; Dimitris Papadopoulos; Manuel Rigo; Charles H. Rivard; Michele Romano; James H Wynne; Monica Villagrasa; Hans-Rudolf Weiss; Fabio Zaina

BackgroundThe International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT), that produced its first Guidelines in 2005, felt the need to revise them and increase their scientific quality. The aim is to offer to all professionals and their patients an evidence-based updated review of the actual evidence on conservative treatment of idiopathic scoliosis (CTIS).MethodsAll types of professionals (specialty physicians, and allied health professionals) engaged in CTIS have been involved together with a methodologist and a patient representative. A review of all the relevant literature and of the existing Guidelines have been performed. Documents, recommendations, and practical approach flow charts have been developed according to a Delphi procedure. A methodological and practical review has been made, and a final Consensus Session was held during the 2011 Barcelona SOSORT Meeting.ResultsThe contents of the document are: methodology; generalities on idiopathic scoliosis; approach to CTIS in different patients, with practical flow-charts; literature review and recommendations on assessment, bracing, physiotherapy, Physiotherapeutic Specific Exercises (PSE) and other CTIS. Sixty-five recommendations have been given, divided in the following topics: Bracing (20 recommendations), PSE to prevent scoliosis progression during growth (8), PSE during brace treatment and surgical therapy (5), Other conservative treatments (3), Respiratory function and exercises (3), Sports activities (6), Assessment (20). No recommendations reached a Strength of Evidence level I; 2 were level II; 7 level III; and 20 level IV; through the Consensus procedure 26 reached level V and 10 level VI. The Strength of Recommendations was Grade A for 13, B for 49 and C for 3; none had grade D.ConclusionThese Guidelines have been a big effort of SOSORT to paint the actual situation of CTIS, starting from the evidence, and filling all the gray areas using a scientific method. According to results, it is possible to understand the lack of research in general on CTIS. SOSORT invites researchers to join, and clinicians to develop good research strategies to allow in the future to support or refute these recommendations according to new and stronger evidence.


The Spine Journal | 2010

The use of the T1 sagittal angle in predicting overall sagittal balance of the spine.

Patrick Knott; Steven Mardjetko; Fernando Techy

BACKGROUND CONTEXT A balanced sagittal alignment of the spine has been shown to strongly correlate with less pain, less disability, and greater health status scores. To restore proper sagittal balance, one must assess the position of the occiput relative to the sacrum. The assessment of spinal balance preoperatively can be challenging, whereas predicting postoperative balance is even more difficult. PURPOSE This study was designed to evaluate and quantify multiple factors that influence sagittal balance. STUDY DESIGN Retrospective analysis of existing spinal radiographs. METHODS A retrospective review of 52 adult spine patient records was performed. All patients had full-column digital radiographs that showed all the important skeletal landmarks necessary for accurate measurement. The average age of the patient was 53 years. Both genders were equally represented. The radiographs were measured using standard techniques to obtain the following parameters: scoliosis in the coronal plane; lordosis or kyphosis of the cervical, thoracic, and lumbar spine; the T1 sagittal angle (angle between a horizontal line and the superior end plate of T1); the angle of the dens in the sagittal plane; the angle of the dens in relation to the occiput; the sacral slope; the pelvic incidence; the femoral-sacral angle; and finally, the sagittal vertical axis (SVA) measured from both the dens of C2 and from C7. RESULTS It was found that the SVA when measured from the dens was on average 16 mm farther forward than the SVA measured from C7 (p<.0001). The dens plumb line (SVA(dens)) was then used in the study. An analysis was done to examine the relationship between SVA(dens) and each of the other measurements. The T1 sagittal angle was found to have a moderate positive correlation (r=0.65) with SVA(dens), p<.0001, indicating that the amount of sagittal T1 tilt can be used as a good predictor of overall sagittal balance. When examining the other variables, it was found that cervical lordosis had a weak correlation (r=0.37) with SVA(dens) that was unexpected, given that cervical lordosis determines head position. Thoracic kyphosis also had a weak correlation (r=0.26) with SVA(C1), which was equally surprising. Lumbar lordosis had a slightly higher correlation (r=0.38), p=.006, than the cervical or thoracic spine. A multiple regression was run on the data to examine the relationship that all these independent variables have on SVA(dens). SPSS (SPSS, Inc., Chicago, IL, USA) was used to create a regression equation using the independent variables of T1 sagittal angle, cervical lordosis, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and femoral-sacral angle and the dependent variable of SVA(dens). The model had a strong correlation (r=0.80, r(2)=0.64) and was statistically significant (p<.0001). The T1 sagittal angle was the variable that had the strongest correlation with the SVA(dens) Spearman r=0.65, p<.0001, followed by pelvic incidence, p=.002, and lumbar lordosis, p=.006. We also observed that when the T1 tilt was higher than 25°, all patients had at least 10 cm of positive sagittal imbalance. In addition, patients with negative sagittal balance had mostly low T1 tilt values, usually lower than 13°. The other variables were not shown to have a statically significant influence on SVA. CONCLUSIONS This analysis shows that many factors influence the overall sagittal balance of the patient, but it may be the position of the pelvis and lower spine that have a stronger influence than the position of the upper back and neck. Unfortunately, to our knowledge, there are no studies to date that have established a normal sagittal T1 tilt angle. However, our analysis has shown that when the T1 tilt was higher than 25°, all patients had at least 10 cm of positive sagittal imbalance. It also showed that patients with negative sagittal balance had mostly low T1 tilt values, usually below 13° of angulation. The T1 sagittal angle is a measurement that may be very useful in evaluating sagittal balance, as it was the measure that most strongly correlated with SVA(dens). It has its great utility where long films cannot be obtained. Patients whose T1 tilt falls outside the range 13° to 25° should be sent for full-column radiographs for a complete evaluation of their sagittal balance. On the other hand, a T1 tilt within the above range does not guarantee a normal sagittal balance, and further investigation should be performed at the surgeons discretion.


Clinical Autonomic Research | 2012

A review of orthostatic blood pressure regulation and its association with mood and cognition.

Lawrence C. Perlmuter; Garima Sarda; Vanessa Casavant; Kimberly O’Hara; Mariah Hindes; Patrick Knott; Aron D. Mosnaim

AimsThis paper will review literature that examines the psychological and neuropsychological correlates of orthostatic blood pressure regulation.ResultsThe pattern of change in systolic blood pressure in response to the shift from supine to upright posture reflects the adequacy of orthostatic regulation. Orthostatic integrity involves the skeletal muscle pump, neurovascular compensation, neurohumoral effects and cerebral flow regulation. Various physiological states and disease conditions may disrupt these mechanisms. Clinical and subclinical orthostatic hypotension has been associated with impaired cognitive function, decreased effort, reduced motivation and increased hopelessness as well as dementia, diabetes mellitus, and Parkinson’s disease. Furthermore, inadequate blood pressure regulation in response to orthostasis has been linked to increased depression and anxiety as well as to intergenerational behavioral sequalae.Conclusions Identifying possible causes and consequences of subclinical and clinical OH are critical in improving quality of life for both children and older adults.


The Spine Journal | 2010

A comparison of magnetic and radiographic imaging artifact after using three types of metal rods: stainless steel, titanium, and vitallium

Patrick Knott; Steven Mardjetko; Richard Kim; Timothy M. Cotter; Megan Dunn; Shivani T. Patel; Matthew J. Spencer; Alan S. Wilson; David S. Tager

BACKGROUND CONTEXT After spinal fusion surgery, postoperative management often includes imaging with either computed tomography (CT) or magnetic resonance imaging (MRI) to assess the spinal canal and nerve roots. The metallic implants used in the fusion can cause artifact that interferes with this imaging, reducing their diagnostic value. Stainless steel is known to produce large amounts of artifact, whereas titanium is known to produce significantly less. Other alloys such as vitallium are now being used in spinal implants, but their comparison to titanium and stainless steel has not been well documented in the orthopedic literature. Titanium is a desirable metal because of its light weight and lower production of artifact on imaging, although it is not as stiff as stainless steel. Vitallium is proposed as a replacement for titanium because it has stiffness similar to stainless steel, while still being as light as titanium. PURPOSE The purpose of this study was to compare the amount of artifact produced on MRI and CT by three types of spinal implants: stainless steel, titanium, and vitallium. STUDY DESIGN A prospective experimental design was used to compare three types of spinal implants used in posterior spinal fusion surgery. OUTCOME MEASURES The resulting images were evaluated by a radiologist to measure the amount of artifact (in millimeters) and by an orthopedic surgeon to assess the diagnostic quality (on a Likert scale). METHODS A porcine torso was used for repeated MRI and CT scans before and after implantation with pedicle screws and rods made of the three metals being studied. RESULTS Images produced after the insertion of vitallium rods and titanium screws as well as those with titanium rods and screws were found to have less artifact and a better overall diagnostic quality than those produced with stainless steel implants. Overall, there was not a difference between the amount of artifact in the spinal images with vitallium and titanium rods, with the exception of a few trials that showed small but statistically significant differences between the two metals, where titanium had slightly better images. CONCLUSIONS If vitallium rods are used in posterior spinal surgery in place of implants made of titanium or stainless steel, any postoperative imaging of the spine using MRI or CT should have amounts of artifact that are similar to titanium and better than stainless steel.


The Open Orthopaedics Journal | 2012

Comparison of Radiographic and Surface Topography Measurements in Adolescents with Idiopathic Scoliosis

Jason M. Frerich; Kristen Hertzler; Patrick Knott; Steven Mardjetko

Purpose: In patients with adolescent idiopathic scoliosis (AIS), radiographic surveillance is the gold standard of assessing spinal deformity, but has negative long-term effects. The Formetric 4D surface topography system was compared to standard radiography as a safer option for evaluating patients with AIS. Methods: Fourteen volunteers with typical AIS patient stature had 30 repeated Formetric 4D measurements taken, and reproducibility was assessed. Sixty-four patients with AIS were then enrolled during routine clinic visits. Evaluation included standard radiographs and surface topography measurements. A comparison analysis was performed. Results: When assessing same-day repeated scans, a standard deviation of +/- 3.4 degrees for scoliosis curve measurements was determined, and the Reliability Coefficient (Cronbach) was very high (0.996). Cobb angles measured with the Formetric 4D differed from radiographic measurements by an average of 9.42 (lumbar) and 6.98 (thoracic) degrees, while the correlation between the two measurements was strong (95% confidence interval [CI]), 0.758 (lumbar) and 0.872 (thoracic) respectively. Conclusions: The Formetric 4D is comparable to radiography in terms of its test-retest reproducibility. Although this device does not predict curve magnitude exactly, the predictions correlate strongly with the Cobb angles determined from radiographs. It can be reliably used in the surveillance of patients with AIS.


Scoliosis | 2014

SOSORT 2012 consensus paper: reducing x-ray exposure in pediatric patients with scoliosis.

Patrick Knott; Eden Pappo; Michelle Cameron; Jc deMauroy; Charles H. Rivard; Tomasz Kotwicki; Fabio Zaina; James H Wynne; Luke Stikeleather; Josette Bettany-Saltikov; Theodoros B Grivas; Jacek Durmała; Toru Maruyama; Stefano Negrini; Joseph P. O’Brien; Manuel Rigo

This 2012 Consensus paper reviews the literature on side effects of x-ray exposure in the pediatric population as it relates to scoliosis evaluation and treatment. Alternative methods of spinal assessment and imaging are reviewed, and strategies for reducing the number of radiographs are developed. Using the Delphi technique, SOSORT members developed consensus statements that describe how often radiographs should be taken in each of the pediatric and adolescent sub-populations.


Spine | 2006

Electromagnetic topographical technique of curve evaluation for adolescent idiopathic scoliosis.

Patrick Knott; Steven Mardjetko; Dorinda K. Nance; Megan Dunn

Study Design. Diagnostic testing. Objective. The goal of this study is to measure the accuracy and reliability of the Orthoscan (Orthoscan Technologies, Inc.) and to determine whether it can be substituted for radiographs in the surveillance of adolescent idiopathic scoliosis (AIS). Summary of Background Data. AIS is usually followed using scoliosis radiographs, which offer the most reliable way to quantify the curve, but carry the risk of exposure to ionizing radiation. The Orthoscan is a nonradiographic topographic method for measuring spinal curves. Materials and Methods. There were 5 phases of this study that measured: the accuracy and reliability of the machine when used with a plastic model; the variability with a real patient; the intraobserver variability; the correlation between the measurements of the machine and that of the radiograph; and the correlation between the change in radiograph measurement over time and the change in Orthoscan measurement over time. Results. In measurement of a static plastic model, the machine measured curves with a standard deviation of ±1° in trunk rotation and ±2° in curve measurement. Error increased with a real patient. Thirty-six comparisons in the thoracic spine, and 19 comparisons in the lumbar spine, were made between measurements using the Orthoscan and radiographs. Mean curves in the 2 groups were not significantly different and had poor-to-moderate correlation. Longitudinal evaluation included 47 curves in 28 patients. The Orthoscan predicted the radiograph change within an acceptable range 55.3% of the time. Conclusions. The Orthoscan does not accurately predict the scoliosis curve magnitude or the overall change in curve over time. While analysis in groups of patients using this technique reveals group means that begin to look acceptable, if the variability is too great, then this technology is not yet ready to replace the radiograph in the evaluation of a scoliosis curve.


Scoliosis | 2010

Terminology - glossary including acronyms and quotations in use for the conservative spinal deformities treatment: 8th SOSORT consensus paper.

Theodoros B Grivas; Jean Claude de Mauroy; Stefano Negrini; Tomasz Kotwicki; Fabio Zaina; James H Wynne; Ian A. F. Stokes; Patrick Knott; Paolo Pizzetti; Manuel Rigo; Monica Villagrasa; Hans Rudolf Weiss; Toru Maruyama

BackgroundThis report is the SOSORT Consensus Paper on Terminology for use in the treatment of conservative spinal deformities. Figures are provided and relevant literature is cited where appropriate.MethodsThe Delphi method was used to reach a preliminary consensus before the meeting, where the terms that still needed further clarification were discussed.ResultsA final agreement was found for all the terms, which now constitute the base of this glossary. New terms will be added after being discussed and accepted.DiscussionWhen only one set of terms is used for communication in a place or among a group of people, then everyone can clearly and efficiently communicate. This principle applies for any professional group. Until now, no common set of terms was available in the field of the conservative treatment of scoliosis and spinal deformities. This glossary gives a common base language to draw from to discuss data, findings and treatment.


Scoliosis | 2010

Evaluation of the reproducibility of the formetric 4D measurements for scoliosis

Patrick Knott; Steven Mardjetko; Michelle Rollet; Scott Baute; Magdelina Riemenschneider; Laura Muncie

Frequent assessment and monitoring of AIS patients is necessary to determine the progression of spinal deformity. Radiographs are used as the standard-of-care for evaluation, but have negative long-term effects. Surface topography is a safer option for assessment in these patients. The Formetric 4D (DIERS, International GmbH of Schlangenbad, Germany) provides fast and radiation-free mages of the spine position using surface topography. The goal of this study was to measure the reproducibility of the Formetric 4D system in measuring trunk dimensions and scoliosis Cobb angles.


Spine deformity | 2016

Multicenter Comparison of 3D Spinal Measurements Using Surface Topography With Those From Conventional Radiography

Patrick Knott; Peter F. Sturm; Baron S. Lonner; Patrick J. Cahill; M. Betsch; Richard E. McCarthy; Michael P. Kelly; Lawrence G. Lenke; Randal R. Betz

INTRODUCTION In pediatric spinal deformity the gold standard for curve surveillance remains standing full-column radiographs, but repeated exposure to ionizing radiation motivates us to look for nonradiographic solutions. This study tests a modern system of surface topography (ST) to determine whether it is reliable and reproducible. METHODS Patients from 6 pediatric spinal deformity clinics were recruited for enrollment. Inclusion criteria were age 8-18; diagnosis of scoliosis measuring ≥10 and <50 degrees or increased kyphosis of ≥45 degrees. Standing radiographs and ST scans (DIERS Formetric, Diers Medical Systems, Chicago, IL) were obtained on all patients and then measured and compared. A single investigator using a validated electronic measurement tool performed all radiographic measurements. Analysis of reproducibility and comparison of ST and radiographs were done. RESULTS A total of 193 patients were enrolled (148 F [77%]). The mean age was 13.25 years (range 8-18). The scoliosis magnitude was as follows: thoracic average 22.7 ± 10 degrees; lumbar average 19.6 ± 9 degrees. The kyphosis magnitude was 54.0 ± 11 degrees. The reproducibility for each ST parameter for 3 repeated scans was strong (interclass correlation = 0.855-0.944). Comparison to radiographic measurements was strong in the thoracic (r = 0.7) and moderate in the lumbar curve (r = 0.5). There was an average difference of 5.8 degrees in the thoracic spine and 8.8 degrees in the lumbar spine between ST Cobb angle estimates and radiographs. Thoracic kyphosis also had a strong correlation (r = 0.8) with radiographs. CONCLUSIONS Although the results are intended to measure similar aspects of deformity as the traditional Cobb angle, the measurement is not intended to be an exact estimation. The utility of ST is in the reproducible quantification of deformity after the initial radiograph has been taken. This has the potential to make longitudinal assessment of change in deformity without serial radiographs.INTRODUCTION In pediatric spinal deformity the gold standard for curve surveillance remains standing full-column radiographs, but repeated exposure to ionizing radiation motivates us to look for nonradiographic solutions. This study tests a modern system of surface topography (ST) to determine whether it is reliable and reproducible. METHODS Patients from 6 pediatric spinal deformity clinics were recruited for enrollment. Inclusion criteria were age 8-18; diagnosis of scoliosis measuring ≥10 and <50 degrees or increased kyphosis of ≥45 degrees. Standing radiographs and ST scans (DIERS Formetric, Diers Medical Systems, Chicago, IL) were obtained on all patients and then measured and compared. A single investigator using a validated electronic measurement tool performed all radiographic measurements. Analysis of reproducibility and comparison of ST and radiographs were done. RESULTS A total of 193 patients were enrolled (148 F [77%]). The mean age was 13.25 years (range 8-18). The scoliosis magnitude was as follows: thoracic average 22.7 ± 10 degrees; lumbar average 19.6 ± 9 degrees. The kyphosis magnitude was 54.0 ± 11 degrees. The reproducibility for each ST parameter for 3 repeated scans was strong (interclass correlation = 0.855-0.944). Comparison to radiographic measurements was strong in the thoracic (r = 0.7) and moderate in the lumbar curve (r = 0.5). There was an average difference of 5.8 degrees in the thoracic spine and 8.8 degrees in the lumbar spine between ST Cobb angle estimates and radiographs. Thoracic kyphosis also had a strong correlation (r = 0.8) with radiographs. CONCLUSIONS Although the results are intended to measure similar aspects of deformity as the traditional Cobb angle, the measurement is not intended to be an exact estimation. The utility of ST is in the reproducible quantification of deformity after the initial radiograph has been taken. This has the potential to make longitudinal assessment of change in deformity without serial radiographs.

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Steven Mardjetko

Rosalind Franklin University of Medicine and Science

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Tomasz Kotwicki

Poznan University of Medical Sciences

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Toru Maruyama

Saitama Medical University

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Fabio Zaina

Mount Royal University

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Fernando Techy

Rosalind Franklin University of Medicine and Science

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Richard Kim

Rosalind Franklin University of Medicine and Science

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Timothy M. Cotter

Rosalind Franklin University of Medicine and Science

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Jacek Durmała

Medical University of Silesia

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