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"Freehand technique"
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Drawn to design : analyzing architecture through freehand drawing
The book is a guide for students and teachers to understand the need for, the role of and the methods and techniques of freehand analytical sketching in architecture. The presentation focuses on drawing as an approach to and phase of architectural design. The conceptual goal of this approach is to use drawing not as illustration or depiction, but exploration. The first part of the book discusses underlying concepts of freehand sketching in design education and practice as a compliment to digital technologies. The main component is a series of chapters that constitute a typology of fundamental issues in architecture and urban design; for instance, issues of \"facade\" are illustrated with sketch diagrams that show how facades can be explored and sketched through a series of specific questions and step-by-step procedures. This book is especially timely in an age in which the false conflict between \"traditional vs. digital\" gives way to multiple design tools, including sketching.
Book
3D-printed drill guide template, a promising tool to improve pedicle screw placement accuracy in spinal deformity surgery: A systematic review and meta-analysis
PurposeThis study aimed to compare the pedicle screw placement accuracy and surgical outcomes between 3D-printed (3DP) drill guide template technique and freehand technique in spinal deformity surgery.MethodsA comprehensive systematic literature search of databases (PubMed, Embase, Cochrane Library, and Web of Science) was conducted. The meta-analysis compared the pedicle screw placement accuracy and other important surgical outcomes between the two techniques. ResultsA total of seven studies were included in the meta-analysis, comprising 87 patients with 1384 pedicle screws placed by 3DP drill guide templates and 88 patients with 1392 pedicle screws placed by freehand technique. The meta-analysis results revealed that the 3DP template technique was significantly more accurate than the freehand technique to place pedicle screws and had a higher rate of excellently placed screws (OR 2.22, P < 0.001) and qualifiedly placed screws (OR 3.66, P < 0.001), and a lower rate of poorly placed screws (OR 0.23, P < 0.001). The mean placement time per screw (WMD–1.99, P < 0.05), total screw placement time (WMD–27.86, P < 0.001), and blood loss (WMD–104.58, P < 0.05) were significantly reduced in the 3DP template group compared with the freehand group. Moreover, there was no significant statistical difference between the two techniques in terms of the operation time and correction rate of main bend curve.ConclusionsThis study demonstrated that the 3DP drill guide template was a promising tool for assisting the pedicle screw placement in spinal deformity surgery and deserved further promotion.
Journal Article
Intraoperative radiation exposure to patients in idiopathic scoliosis surgery with freehand insertion technique of pedicle screws and comparison to navigation techniques
PurposeIn surgical correction of scoliosis with pedicle screw dual-rod systems, frequently used freehand technique of screw positioning is challenging due to 3D deformity. Screw malposition can be associated with serious complications. Image-guided technologies are already available to improve accuracy of screw positioning and decrease radiation to surgeon. This study was conducted to measure intraoperative radiation to patients in freehand technique, evaluate screw-related complications and compare radiation values to published studies using navigation techniques.MethodsRetrospective analysis of prospectively collected data of 73 patients with idiopathic scoliosis, who underwent surgical correction with pedicle screw dual-rod system. Evaluated parameters were age, effective radiation dose (ED), fluoroscopy time, number of fused segments, correction and complications. Parameters were compared with regarding single thoracic curve (SC) and double thoracic and lumbar curves (DC), adolescent (10–18 years) or adult (> 18 years) idiopathic scoliosis, length of instrumentation. ED was compared with values for navigation from online database.ResultsAverage age was 21.0 ± 9.7 years, ED was 0.17 ± 0.1 mSv, time of fluoroscopy was 24.1 ± 18.6 s, 9.5 ± 1.9 fused segments. Average correction for SC was 75.7%, for DC 69.9% (thoracic) and 76.2% (lumbar). No screw-related complications. ED was significantly lower for SC versus DC (p < 0.01), short versus long fusions (p < 0.01), no significant difference for age (p = 0.1). Published navigation data showed 6.5- to 8.8-times higher radiation exposure for patients compared to our results.ConclusionCompared to navigation procedures, freehanded positioning of pedicle screws in experienced hands is a safe and effective method for surgical correction of idiopathic scoliosis with a significant decrease in radiation exposure to patients.
Journal Article
Sketching user experiences
Sketching Working Experience: The Workbook provides information about the step-by-step process of the different sketching techniques.It offers methods called design thinking, as a way to think as a user, and sketching, a way to think as a designer.
eBook
Characteristics of pedicle screw misplacement using freehand technique in degenerative scoliosis surgery
PurposeThis study aimed to estimate the accuracy of pedicle screw (PS) placement in degenerative scoliosis surgery, characterize a patient population with PS misplacement, and analyze the association between misplaced PS vector and lumbar coronal curve.MethodsIn this study, 122 patients (average age 68.6 years), who underwent corrective and decompression surgery, were selected retrospectively. PS accuracy was evaluated in the thoracic to lumbar spine. We identified characteristics of misplacement in each patient. Screw positions were categorized into grade A, entirely in the pedicle; grade B, < 2 mm breach; grade C, 2–4 mm breach; and grade D, > 4 mm breach using postoperative computed tomography.ResultsThe mean preoperative lumbar coronal curve was 32.3 ± 18.4°, and the number of fused vertebrae was 8.9 ± 2.8. A total of 2032 PS were categorized as follows: grade A, 1897 PS (93.3%); grade B, 67 (3.3%); grade C, 26 (1.3%); and grade D, 43 (2.1%). One PS (grade D), inserted at T5, needed surgery for removal due to neurological deficit. The misplacement group (grades C and D) had a significantly stronger lumbar coronal curve and apical vertebral rotation than the accuracy group (grades A and B). Misplaced PS vector (direction and degree) was significantly correlated with inserted vertebral rotation. Grade D misplacement was distributed mainly around the transitional vertebra of the lumbar curve.ConclusionsThe accuracy of PS insertion in the thoracic to lumbar spine was high in DS surgery, but the need for care was highlighted in the transitional vertebra.
Journal Article
Comparison of Superior‐Level Facet Joint Violations Between Robot‐Assisted Percutaneous Pedicle Screw Placement and Conventional Open Fluoroscopic‐Guided Pedicle Screw Placement
Objective To compare the superior‐level facet joint violations (FJV) between robot‐assisted (RA) percutaneous pedicle screw placement and conventional open fluoroscopic‐guided (FG) pedicle screw placement in a prospective cohort study. Methods This was a prospective cohort study without randomization. One‐hundred patients scheduled to undergo RA (n = 50) or FG (n = 50) transforaminal lumbar interbody fusion were included from February 2016 to May 2018. The grade of FJV, the distance between pedicle screws and the corresponding proximal facet joint, and intra‐pedicle accuracy of the top screw were evaluated based on postoperative CT scan. Patient demographics, perioperative outcomes, and radiation exposure were recorded and compared. Perioperative outcomes include surgical time, intraoperative blood loss, postoperative length of stay, conversion, and revision surgeries. Results Of the 100 screws in the RA group, 4 violated the proximal facet joint, while 26 of 100 in the FG group had FJV (P = 0.000). In the RA group, 3 and 1 screws were classified as grade 1 and 2, respectively. Of the 26 FJV screws in the FG group, 17 screws were scored as grade 1, 6 screws were grade 2, and 3 screws were grade 3. Significantly more severe FJV were noted in the FG group than in the RA group (P = 0.000). There was a statistically significant difference between RA and FG for overall violation grade (0.05 vs 0.38, P = 0.000). The average distance of pedicle screws from facet joints in the RA group (4.16 ± 2.60 mm) was larger than that in the FG group (1.92 ± 1.55 mm; P = 0.000). For intra‐pedicle accuracy, the rate of perfect screw position was greater in the RA group than in the FG group (85% vs 71%; P = 0.017). No statistically significant difference was found between the clinically acceptable screws between groups (P = 0.279). The radiation dose was higher in the FG group (30.3 ± 11.3 vs 65.3 ± 28.3 μSv; P = 0.000). The operative time in the RA group was significantly longer (184.7 ± 54.3 vs 117.8 ± 36.9 min; P = 0.000). Conclusions Compared to the open FG technique, minimally invasive RA spine surgery was associated with fewer proximal facet joint violations, larger facet to screw distance, and higher intra‐pedicle accuracy.
Journal Article
Analysis on the related factors of misplacement of freehand pedicle screws via posterior approach in degenerative scoliosis
Background
To study the risk factors associated with misplacement of freehand pedicle screws through a posterior approach for degenerative scoliosis.
Methods
A total of 204 patients who underwent posterior pedicle screw-rod system surgery for degenerative scoliosis in our hospital from December 2020 to December 2023 were retrospectively analyzed. Patient demographics, radiographic accuracy, and surgery-related information were recorded.
Results
A total of 204 patients were included. A total of 2496 screws were placed. 2373 (95.07%) were in good position. Misplacement screws were 123 (4.93%). None of the patients had postoperative spinal nerve symptoms due to screw malposition. The misplacement rate of thoracic (T10-T12) pedicle screws was 11.11% (60/540). Misplacement of pedicle screws in the lumbar spine (L1-L5) was 3.22% (63/1956). Age, gender, surgeon, and operation time had no significant effect on misplacement of pedicle screws (
P
>0.05). Body mass index, Hu value, number of screw segments, Cobb angle, vertebral rotation, and spinal canal morphology had some correlation with pedicle screw misplacement. Among them, BMI, Hu value, number of screw segments, Cobb angle, and vertebral rotation grade were independent risk factors for PS misplacement (
P
<0.05). The height of the posterior superior iliac spine had a significant effect on pedicle screw misplacement in the lower lumbar spine (L4/5) (
P
<0.05).
Conclusion
BMI, Hu value, number of screw levels, Cobb angle, and vertebral rotation grade were independent risk factors for pedicle screw misplacement in patients with degenerative scoliosis. Posterior superior iliac spine height has a large impact on PS placement in the lower lumbar spine. Patients with degenerative scoliosis should be preoperatively planned for the size and direction of the placed screws by X-ray and CT three-dimensional, to reduce the misplacement rate of pedicle screws.
Journal Article
Comparison of Safety and Perioperative Outcomes Between Patient-specific Template-Guided and Fluoroscopic-Assisted Freehand Lumbar Screw Placement Using Cortical Bone Trajectory Technique
Study Design
Non-randomized prospective controlled study
Objectives
To compare the safety and perioperative outcomes between patient-specific template-guided and fluoroscopic-assisted freehand techniques in transforaminal lumbar interbody fusion (TLIF) using cortical bone trajectory (CBT).
Methods
The subjects consisted of 94 consecutive patients who underwent single-level TLIF using CBT. The standard trajectory was set so as to start from the pars interarticularis, pass the inferior border of the pedicle, and end around the middle of the vertebral endplate. Template guide technique was performed in 66 patients (Guide group), and fluoroscopic-assisted freehand technique was performed in 28 patients (Freehand group). Intraoperative parameters, screw placement accuracy, and complications were compared between the two techniques.
Results
The Guide group had significantly shorter operative and radiation exposure times than the Freehand group (operative time 84.6 ± 16.7 vs 93.0 ± 15.0 minutes; P = .023, radiation exposure time 7.0 ± 6.0 vs 20.4 ± 11.8 seconds; P < .001, respectively). The screw diameter and the screw insertion depth in the vertebra in the Guide group were significantly greater than those in the Freehand group. The degree and incidence of facet joint violation were comparable between the two groups, while the accuracy of screw placement was significantly different, with no perforation rate of 97.7% in the Guide group vs 82.1% in the Freehand group (P < .001). No significant difference was found in the rate of clinically relevant complications between the two groups.
Conclusions
The template-guided technique provided a safe and highly accurate option for CBT screw placement.
Journal Article