Dimensional Characterization of the Human Cervical Interlaminar Space as a Guide for Safe Application of Minimally Invasive Dilators

2020 ◽  
Vol 19 (3) ◽  
pp. E275-E282 ◽  
Author(s):  
Luis M Tumialán ◽  
Jennifer N Lehrman ◽  
Celene B Mulholland ◽  
Bernardo de Andrada Pereira ◽  
Anna G U S Newcomb ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Minimally Invasive ◽  
Small Diameter ◽  
Spinal Level ◽  
Vertebral Level ◽  
Neutral Posture ◽  
Coordinate Data ◽  
Theoretical Risk ◽  
Flexion And Extension

Abstract BACKGROUND The risk of interlaminar passage of a dilator into the cervical spinal canal in minimally invasive approaches is currently unknown. Among the various anthropometric data reported in the literature, there is no report of the interlaminar dimensions in the cervical spine. OBJECTIVE To report the cervical interlaminar dimensions in neutral, flexion, and extension. METHODS A total of 8 spines were sectioned into cervical (C2-T1) segments. Digitized coordinate data defining the locations and movements of chosen anatomic points on the laminar edges at a given spinal level were used to compute the dimensions during a static neutral posture, flexion, and extension positions to mimic the positions during surgery. Interlaminar dimensions were averaged and categorized for each vertebral level and spinal posture. RESULTS Based on the reported measurements, the smallest diameter dilator in commonly used dilator sets has the potential to traverse the interlaminar space at all levels in flexion. In a neutral posture, the average interlaminar distance at C2-3, C6-7, and C7-T1 was still greater than 2.0 mm, the smallest diameter of the initial dilator. The largest interlaminar distance was at C6-7 in flexion (7.68 ± 1.60 mm). CONCLUSION Because dilators pass directly onto the cervical lamina without visualization of the midline structures, the interlaminar distances have increased relevance in the minimally invasive cervical approaches of foraminotomy and laminectomy. The data in this report demonstrate the theoretical risk of interlaminar passage with small diameter dilators in posterior minimally invasive approaches to the cervical spine.

Dimensional Characterization of the Human Lumbar Interlaminar Space as a Guide for Safe Application of Minimally Invasive Dilators

2021 ◽  
Author(s):  
Jennifer N Lehrman ◽  
Celene B Mulholland ◽  
Bernardo de Andrada Pereira ◽  
Anna G U Sawa ◽  
Brian P Kelly ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Spinal Level ◽  
Flexion Extension ◽  
Minimally Invasive Spine ◽  
The Mean ◽  
Lumbar Spinal ◽  
Neutral Posture ◽  
Coordinate Data ◽  
Flexion And Extension

Abstract BACKGROUND The risk of interlaminar passage of a dilator into the lumbar spinal canal in minimally invasive approaches is currently unknown. Among anthropometric data reported in the medical literature, there is no cadaveric report of the interlaminar dimensions of the lumbar spine. OBJECTIVE To report the lumbar interlaminar dimensions in neutral, flexion, and extension postures. METHODS A total of 8 spines were sectioned into lumbar segments. Digitized coordinate data defining the locations and movements of chosen anatomic points on the laminar edges at a given spinal level were used to measure changes in the opening dimensions during static neutral posture and flexion-extension movements. Interlaminar dimensions were averaged and categorized for each vertebral level and spinal posture. RESULTS The mean interlaminar distance increased from neutral posture to flexion across all vertebral levels. The mean interlaminar distances in the neutral posture ranged from 12.21 mm (L5-S1) to 14.88 mm (L1-L2). In flexion, the range was from 17.15 mm (L5-S1) to 18.50 mm (L4-L5). These measurements are greater than the first several diameters of dilators in all minimally invasive dilator sets. CONCLUSION The precise measurements of the lumbar interlaminar space are valuable to minimally invasive spine surgeons for the dilatation phase of the operation. The risk of interlaminar passage of a minimally invasive dilator is greatest in flexion with dilators that have a diameter of 16 mm or less. There is considerably less risk of interlaminar passage in patients positioned on an extended Jackson table.

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

Motion Analysis of the Cervical Spine

2004 ◽  
Vol 9 (5) ◽  
pp. 1-11
Author(s):  
Patrick R. Luers
Keyword(s):  
Cervical Spine ◽  
Intervertebral Disk ◽  
Radiographic Evaluation ◽  
Ligamentous Injury ◽  
Pattern Of Injury ◽  
Motion Segment ◽  
Single Pattern ◽  
Compensatory Motion ◽  
Loss Of Motion ◽  
Flexion And Extension

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, defines a motion segment as “two adjacent vertebrae, the intervertebral disk, the apophyseal or facet joints, and ligamentous structures between the vertebrae.” The range of motion from segment to segment varies, and loss of motion segment integrity is defined as “an anteroposterior motion of one vertebra over another that is greater than 3.5 mm in the cervical spine, greater than 2.5 mm in the thoracic spine, and greater than 4.5 mm in the lumbar spine.” Multiple etiologies are associated with increased motion in the cervical spine; some are physiologic or compensatory and others are pathologic. The standard radiographic evaluation of instability and ligamentous injury in the cervical spine consists of lateral flexion and extension x-ray views, but no single pattern of injury is identified in whiplash injuries. Fluoroscopy or cineradiographic techniques may be more sensitive than other methods for evaluating subtle abnormal motion in the cervical spine. The increased motion thus detected then must be evaluated to determine whether it represents normal physiologic motion, normal compensatory motion, motion related to underlying degenerative disk and/or facet disease, or increased motion related to ligamentous injury. Imaging studies should be performed and interpreted as instructed in the AMA Guides.

Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

2018 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Zhicheng Jin ◽  
Eric Lochner ◽  
Hedi Mattoussi
Keyword(s):  
Quantum Yield ◽  
Near Infrared ◽  
Small Diameter ◽  
Binding Energies ◽  
Thiolate Ligands ◽  
Nir Emission ◽  
Thiolate Complexes ◽  
Long Lifetime ◽  
Poly Ethylene

<p>We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au<sub>25-x</sub>Ag<sub>x</sub> cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au<sub>11</sub> clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.<br></p>

CHARACTERIZATION OF CERVICAL SPINE IMPAIRMENTS IN CHILDREN AND ADOLESCENTS POST-CONCUSSION

2019 ◽  
Vol 14 (2) ◽  
pp. 282-295 ◽  
Author(s):  
Devashish Tiwari ◽  
Allon Goldberg ◽  
Amy Yorke ◽  
Gregory F. Marchetti ◽  
Bara Alsalaheen
Keyword(s):  
Cervical Spine ◽  
Children And Adolescents

Characterization of silk sponge in the wet state using13C solid state NMR for development of a porous silk vascular graft with small diameter

RSC Advances ◽  
2014 ◽  
Vol 4 (9) ◽  
pp. 4427-4434 ◽  
Author(s):  
Tetsuo Asakura ◽  
Toshiki Saotome ◽  
Derya Aytemiz ◽  
Haruka Shimokawatoko ◽  
Takahito Yagi ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Vascular Graft ◽  
Small Diameter

Development and Biomechanical Characterization of a Novel Bilayer Vascular Graft

2010 ◽  
Author(s):  
Krishna Madhavan ◽  
Walter Bonani ◽  
Craig Lanning ◽  
Wei Tan
Keyword(s):  
Blood Vessel ◽  
Vascular Graft ◽  
Bypass Surgery ◽  
Small Diameter ◽  
Native Artery ◽  
Vessel Lumen ◽  
Unmet Demand ◽  
Tissue Engineered Blood Vessels ◽  
Synthetic Grafts

Vascular grafts are currently used to treat cardiovascular diseases such as arthrosclerosis by bypass surgery and as vascular access in hemodialysis [1]. There are a number of types of grafts including autologous vessels (such saphenous vein), synthetic grafts (such as expanded polytetrafluoroethylene) and tissue engineered blood vessels. Currently synthetic grafts are most commonly used as blood vessel replacements and there are a number of problems associated with them. One main impediment is that these grafts are not suitable for small-diameter (less than 6mm) vessel replacement [1, 2], due to high occlusion rates. The major concern over the other alternatives such as autologous vessels and tissue engineered products is their availability. Thus, new approaches to constructing biomimetic small-diameter blood vessel equivalents, that are immediately available, may address the unmet demand in this area. Therefore, we have designed a novel bilayer vascular construct which is made up of a nanofibrous intimal-equivalent as thromboresistant vessel lumen and a mimetic extracellular matrix (ECM) as medial-equivalent for smooth muscle cells (SMC) from native artery to invade and remodel the ECM.

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