Cadaveric Torsos Research Articles

Enhancing Cadaver Labs for Endoscopic Spine Surgery: The Glove as the “Lesion”

We describe a novel yet simple training exercise for residents who are being introduced to endoscopic spine surgery. Prior to residents training on the endoscopic interlaminar approach, the course faculty performed an endoscopic transforaminal approach and inserted a small piece of a surgical glove into the ventral epidural space of a cadaveric torso. The transforaminal approach did not alter the anatomy of the interlaminar approach so the residents were able to practice as if it were a de novo situation. Placing the small "lesion" provided an exercise to confirm the residents were able to safely access the area and provided practice for them to carefully grasp the "lesion" and remove it. Prior to resident training on the endoscopic transforaminal approach, the course faculty utilized an interlaminar approach to place the "lesion". A questionnaire with a five-point Likert scale of agreement was completed by the residents to assess their experience with the training exercise. Five residents attended the cadaver lab, and 100% strongly agreed that the cadaver lab provided a realistic representation of the procedure demonstrated, the "lesion" removal added to their educational experience, and they were overall satisfied with the educational session. One of the lessons learned with this exercise that we will consider in future courses would be to place a radiodense "lesion" that could be visualized on fluoroscopy, and serve as a radiologic target to find. This can help guide the trainee in knowing where to search if the "lesion" is more difficult to find.

Commercial suture passer improves efficiency and ease of use versus conventional needle in minimally invasive thoracolumbar fascia closure: a cadaveric analysis

BackgroundLow-profile suture passers have been introduced to facilitate thoracolumbar fascia closure in minimally invasive spine (MIS) surgery. The purpose of this study was to evaluate the closure time of a modern suture passer to a conventional curved need for MIS fascia closure in a cadaveric model. MethodsSix clinicians specializing in orthopedic spine surgery were recruited for the study and randomly assigned 1 cadaveric torso. Subcutaneous tissue was resected at L4-L5, replicating MIS surgery, followed by placement of a 60×18-mm or 100×18-mm tubular retractor for access. Clinicians were required to close the fascia with three unknotted, simple interrupted sutures using a swaged curved needle or suture passer (Spine Scorpion™, Arthrex, Inc., Naples, FL). The completion time was recorded, starting immediately before suturing and ending after the last pass. A time cutoff of 10 min was implemented in consideration of reasonable operating room time, and the number of achieved suture passes (of 6) were recorded. Clinicians were asked to qualitatively grade ease of use in relation to prior fascial closure experience per a 0-5 scale, where 0 is impossible and 5 is easiest. ResultsThe mean change in fascial closure completion time (Δ) was significantly reduced with the Spine Scorpion compared to the curved needle with the 60×18-mm retractor (Δ=5.80 min; 95% CI, 2.92-8.67 min; p=.004) and 100 × 18-mm retractor (Δ=5.28 min; 95% CI, 2.76-7.80 min; p=.003). Full closure was achieved within the time limit for all trials of the Spine Scorpion, while the standard needle achieved full closure in 67% (4 of 6) and 50% (3 of 6) of trials with the 60 × 18-mm and 100×18-mm retractors, respectively. Median ease-of-use scores with the 60×18-mm and 100×18-mm retractors, respectively, were 4.5 (range, 4-5) and 4.5 (range, 3-5) for the Spine Scorpion, and both 1.0 (range, 1-2) for the curved needle. ConclusionResults from this laboratory investigation using a suture passer for thoracolumbar fascia closure show a significant reduction in closure time and completion of the procedure compared to a conventional curved needle.

Superior metal artifact reduction of tin-filtered low-dose CT in imaging of lumbar spinal instrumentation compared to conventional computed tomography

ObjectiveTo compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction.Materials and methodsCT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lumbar implants were scanned with both standard CT (120 kV) and tin-filtered LD-CT (Sn140kV). CT dose parameters and qualitative measures (1 = worst,4 = best) were compared. Quantitative measures included noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and the width and attenuation of the most prominent hypodense metal artifact. Standard CT and LD-CT were assessed for imaging findings.ResultsTin-filtered LD-CT was performed with 60% dose saving compared to standard CT (median effective dose 3.22 mSv (quartile 1–3: 2.73–3.49 mSv) versus 8.02 mSv (6.42–9.27 mSv; p < .001). Image quality of CT and tin-filtered low-dose CT was good with excellent depiction of anatomy, while image noise was lower for CT and artifacts were weaker for tin-filtered LD-CT. Quantitative measures also revealed increased noise for tin-filtered low-dose CT (41.5HU), lower SNR (2) and CNR (0.6) compared to CT (32HU,3.55,1.03, respectively) (all p < .001). However, tin-filtered LD-CT performed superior regarding the width and attenuation of hypodense metal artifacts (2.9 mm and -767.5HU for LD-CT vs. 4.1 mm and -937HU for CT; all p < .001). No difference between methods was observed in detection of imaging findings.ConclusionTin-filtered LD-CT with 60% dose saving performs comparable to standard CT in detection of pathology and surgery related complications after lumbar spinal instrumentation, and shows superior metal artifact reduction.

Risk of Injury to Retroperitoneal Structures in Prone and Lateral Decubitus Transpsoas Approaches to Lumbar Interbody Fusion: A Pilot Cadaveric Anatomical Study.

Introduction The retroperitoneal approach for lateral lumbar interbody fusion (LLIF) originally described an initial posterolateral fascial incision enabling finger dissection from behind the peritoneum and guidance of instruments through a second direct-lateral fascial incision. It has since become common for single direct-lateral incisional access to the retroperitoneum. This study attempted to quantify the distance of the peritoneum from posterior landmarks in the space, assess the risk of peritoneal violation in each access trajectory (i.e., posterolateral versus direct lateral retroperitoneal dissection), and determine whether there are differences based on patient position (prone versus lateral decubitus). Methods In three prone cadaveric torsos, Steinman pins were percutaneously placed mid-disc at each level L2-5 bilaterally (for a total of 18 prone approaches). Open dissections exposed the retroperitoneum including the quadratus lumborum and psoas muscles, maintaining the natural reflection of the peritoneum. Visual assessment qualified whether any pin violated any retroperitoneal structure. Distance from the anterior border of the quadratus lumborum to the posterior-most reflection of the peritoneum was measured. For comparison, three additional torsos were positioned in lateral decubitus, and the above steps were repeated, only unilaterally (for a total of nine lateral decubitus approaches). Results In prone, no pin violated the peritoneum; three (3/18 total approaches) violated the kidney, all at L2-3 (3/6 approaches at L2-3). In lateral decubitus, all three L2-3 pins violated the kidney (3/3 approaches at L2-3); five of the six remaining pins from L3-5 violated the peritoneum (totaling eight violations in the nine total approaches). The incidence of any violation was significantly greater in lateral decubitus vs. prone (8/9 vs. 3/18, p=0.0006). The structure at risk (kidney vs. peritoneum) was significantly associated with disc level (p=0.0041): all kidney violations occurred at L2-3 and all peritoneal violations occurred at L3-4 or L4-5. Distance from the quadratus lumborum to the posterior-most reflection of the peritoneum averaged 8.7 cm (range: 6-10) in prone, and 2.9 cm (range: 2.5-3.2) in lateral decubitus (p=0.0129). Conclusion A cadaveric study of retroperitoneal anatomy demonstrates that there is an increased distance from the quadratus lumborum to the peritoneum in prone versus lateral decubitus and that the trajectory of approach to the lumbar discs risks violation of the peritoneum more frequently when accessing directly laterally versus posterolaterally. In either approach, care should be taken to identify and release the peritoneal reflection to create a safe passage to the lumbar discs.

Ultrasound Shear Wave Elastography Quantitatively Assesses Tension Changes of Supraspinous/Interspinous Ligament Complex Under Varied Loads.

Although interspinous and supraspinous ligaments of the lumbar spine are thought to contribute to spinal stability, little is known about their dynamic biomechanics. We demonstrate that shear wave elastography (SWE) offers a novel technique to noninvasively and quantitatively evaluate posterior spinous ligament complex functional loading and stiffness in different physiologic positions. We performed SWE and measured the length of the interspinous/supraspinous ligament complex in cadaveric torsos (N = 5), isolated ligaments (N = 10), and healthy volunteers (N = 9) to obtain length and shear wave velocity measurements. For cadavers and volunteers, SWE was utilized in 2 lumbar positions: lumbar spine flexion and extension. In addition, SWE was performed on isolated ligaments undergoing uniaxial tension to correlate shear wave velocities with experienced load. Average shear wave velocity in cadaveric supraspinous/interspinous ligament complexes increased for lumbar levels (23%-43%) and most thoracic levels (0%-50%). This corresponded to an average increase in interspinous distance from extension to flexion for the lumbar spine (19%-63%) and thoracic spine (3%-8%). Volunteer spines also demonstrated an average increase in shear wave velocity from extension to flexion for both the lumbar spine (195% at L2-L3 to 200% at L4-L5) and thoracic spine (31% at T10-T11). There was an average increase in interspinous distance from extension to flexion for the lumbar spine (93% at L2-L3 to 127% at L4-L5) and thoracic spine (11% at T10-T11). In isolated ligaments, there was a positive correlation between applied tensile load and average shear wave velocity. This study creates a foundation to apply SWE as a noninvasive tool for assessing the mechanical stiffness of posterior ligamentous structures and has potential applications in augmenting or evaluating these ligaments in patients with spine pathology. The interspinous and supraspinous ligaments are critical soft tissue supports of the posterior lumbar spine. Disruption of these structures is thought to have a negative impact on spinal stability in trauma and spine deformities.

OC-073 PATHWAYS OF THE PREPERITONEAL PLANE: FROM THE “FATTY TRIANGLE” IN RIVES TO THE “FATTY TRIDENT” IN EXTENDED RETROMUSCULAR ABDOMINAL WALL RECONSTRUCTION

Abstract Aim Retromuscular dissection performed for abdominal wall reconstruction in complex abdominal wall has progressively exposed the anatomy between the peritoneal layer and abdominal wall muscles. This study aimed to assess the morphology and distribution of preperitoneal fat in a cadaveric model and its influence on retromuscular preperitoneal dissections. Material &amp; Methods Thirty frozen cadaver torsos were dissected by posterior component separation (PCS). The shape of the preperitoneal fat was identified, and the dimensions and distances were calculated. Results Results showed that preperitoneal fat resembles a trident, along the midline under the linea alba, and expands in the epigastrium into a rhomboid shape. The fatty triangle was found to be a part of this rhomboid. Caudally, the midline preperitoneal fat widened under the arcuate line to reach Retzius´s space. Bogros space communicated the root of the trident laterally with the paracolic gutters, Toldt's fascia, and pararenal fats, forming the lateral prong of the trident. The peritoneum uncovered by the preperitoneal trident was easy to break. Three pathways could be tracked following the distribution of this fat that facilitated the dissection of the preperitoneal space to prepare the landing zone of the meshes in hernia repair. Conclusion The concept of preperitoneal fatty trident may be of practical assistance in performing hernia procedures, from the simple ventral hernia repair to more complex preperitoneal ventral repair or PCS techniques. The consistency of this layer allows us to follow three specific pathways to the plane between the peritoneum and muscles to extend the preperitoneal dissection.

P-100 ANATOMICAL STUDY ON THE PREPERITONEAL FAT DISTRIBUTION IN EXTENDED RETROMUSCULAR PREPERITONEAL DISSECTION: FROM THE FATTY TRIANGLE TO THE FATTY TRIDENT

Abstract Aim Extended retromuscular dissection performed for abdominal wall reconstruction in complex abdominal wall repair has progressively exposed the anatomy between the peritoneal layer and abdominal wall muscles. This study aimed to assess the morphology and distribution of preperitoneal fat in a cadaveric model. Material and methods Thirty frozen cadaver torsos were dissected by posterior component separation. The shape of the preperitoneal fat was identified, and the dimensions and more significant distances were calculated. Results The results showed that the preperitoneal fat resembles a trident, exists along the midline under the linea alba, and expands in the epigastric area into a rhomboid shape. The fatty triangle was found to be a part of this rhomboid. The mean rhomboid area was 35 cm2. Caudally, the midline preperitoneal fat widened under the arcuate line to reach the Retzius space. Laterally, the Bogros space communicated the root of the trident with the paracolic gutters, Toldt's fascia, and pararenal fats, forming the lateral prong of the trident. The mean width of the midline prong at the umbilicus was 2.8 cm. It was easier to tear the peritoneum outside the area reinforced by the fatty trident. Conclusions The concept of preperitoneal fatty trident may be of practical assistance to perform various hernia procedures, from the simple ventral hernia repair to the more complex preperitoneal ventral repair or posterior component separation techniques. The consistency of this layer allows us to follow our plane between the peritoneum and muscle layers to extend the preperitoneal dissection.

Kinematic and Radiographic Evaluation of Acromioclavicular Reconstruction with a Synthetic Ligament.

Purpose The optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (CC) joint injuries has not yet been established. The biomechanical and radiographic effect of the LockDown device, a synthetic ligament for AC joint reconstruction, was evaluated to assess the optimal surgical technique for unstable AC and CC joint injuries. It was hypothesized that the LockDown device would restore AC joint kinematics and radiographic stability to near native values. Methods Three fresh frozen cadaveric torsos (6 shoulders) modelled CC joint motion in their “native,” “severed,” and “reconstructed” states. The effects of stressed and unstressed native, severed, and reconstructed conditions on AC separation and CC distances in anteroposterior, mediolateral, and inferosuperior directions during shoulder abduction, flexion, and scaption were assessed. The analysis of variance (p, 0.05) was used to compare CC distance and peak AC distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder flexion, abduction, and scaption measurements among native, severed, and reconstructed states with unstressed and stressed Zanca radiographic views. Results From radiographic analyses, the CC distance was significantly greater (p=0.001) across the surgical state in stressed versus unstressed views. Mean difference between stressed and unstressed views was 1.8 mm in native state, 4.1 mm in severed state, and 0.9 mm in reconstructed state. The CC distance was significantly greater in the “severed” state (10.4 mm unstressed; 14.5 mm stressed) compared to the “native” state (p=0.016) (6.5 mm unstressed; 8.3 mm stressed) and compared to the “reconstructed” state (p=0.005) (3.1 mm unstressed; 4.0 mm stressed) and significantly less (p=0.008) in the “reconstructed” state compared to the “native” state. CC distances decreased from native to reconstructed, an average of 3.3 mm for unstressed and 4.3 mm for stressed. On average, peak AC joint separation distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder-abduction, flexion, and scaption was shown to be restored to 11.5 mm of native values after reconstruction with LockDown device. Conclusion Reconstruction of AC joint with LockDown synthetic ligament restores motion of clavicle and acromion to near native values, thereby decreasing scapular dyskinesis and enhancing AC joint stability.

Augmented Reality-Assisted Percutaneous Pedicle Screw Instrumentation: A Cadaveric Feasibility and Accuracy Study

Percutaneous pedicle screw instrumentation is the keystone of minimally invasive spine surgery. Percutaneous screw placement demands experience and relies greatly on intra-operative image guidance. This study aims to validate the feasibility and accuracy of augmented-reality (AR)-assisted percutaneous pedicle screw instrumentation. One cadaveric torso was prepared for this study. After a pre-operative computed tomography (CT) scan, the images were transferred to an AR station to generate a 3D hologram. The 3D hologram and navigation images were projected to a pair of goggles with a display screen. With registration, the 3D spine hologram was overlayed onto the cadaver. Bilateral instrumentation from T6 to L5 was performed by two surgeons using AR assistance. A post-operative CT scan was obtained. The Gertzbein–Robbins scale (grade 0–3) was used for accuracy assessment. A total of 24 screws were placed. The overall screw accuracy was 87.5%. There were three major medial breaches that occurred on Rt T6/7/8, which were the most distant screws from the iliac reference. The cause of the three major medial breaches appeared to be related to their distance from the iliac reference. AR-assisted percutaneous pedicle screw instrumentation could improve anatomical visualization, facilitate surgical workflow, and provide an intuitive way of performing surgery.

Human Exposure to Hand-Arm Vibration from a Surgical Drill During Simulated Spine Surgery

During spine surgery, surgeons are exposed to vibrations from surgical drills. Increased exposure to vibration can result in neurologic, vascular, and musculoskeletal impairments. To reduce these risks, occupational health standards have been implemented to limit exposure levels. The purpose of this study was to quantify human exposure to hand-arm vibration from a surgical drill during a simulation of a common spine procedure. Vibration measurements were collected during three 30-second surgical trials on a fresh frozen cadaver torso specimen using a standard surgical drill. The daily vibration exposure A(8) was evaluated on the basis of International Organization for Standardization 5349-1, and the occupational health standards, exposure action value, and exposure limit value were calculated. On the basis of vibration exposure, surgeons in this study reached their exposure limits in 8 minutes to monitor tool usage and 32 minutes to terminate equipment usage. The results demonstrate that a common surgical drill transmits hand-arm vibration levels approaching the exposure action value and exposure limit value over short periods of use. Further investigation is needed to determine the total vibration exposure over an entire workday, specifically in surgeons who perform multiple surgeries within a single day.

Pathways of the preperitoneal plane: from the "fatty triangle" in Rives to the "fatty trident" in extended retromuscular abdominal wall reconstruction. A tribute toProf. Schumpelick.

Extended retromuscular dissection performed for abdominal wall reconstruction in complex abdominal wall repair has progressively exposed the anatomy between the peritoneal layer and abdominal wall muscles. This study aimed to assess the morphology and distribution of preperitoneal fat in a cadaveric model and its influence in retromuscular preperitoneal dissections. Thirty frozen cadaver torsos were dissected by posterior component separation. The shape of the preperitoneal fat was identified, and the dimensions and more significant distances were calculated. The results showed that the preperitoneal fat resembles a trident, exists along the midline under the linea alba, and expands in the epigastric area into a rhomboid shape. The fatty triangle was found to be a part of this rhomboid. Caudally, the midline preperitoneal fat widened under the arcuate line to reach the Retzius space. Laterally, the Bogros space communicated the root of the trident with the paracolic gutters, Toldt's fascia, and pararenal fats, forming the lateral prong of the trident. The peritoneum not covered by the preperitoneal fatty trident was easy to break. Three pathways could be tracked following the distribution of this fat that facilitated the dissection of the preperitoneal space to prepare the landing zone of the meshes in hernia repair. The concept of preperitoneal fatty trident may be of practical assistance to perform various hernia procedures, from the simple ventral hernia repair to the more complex preperitoneal ventral repair or posterior component separation techniques. The consistency of this layer allows us to follow three specific pathways to find our plane between the peritoneum and muscle layers to extend the preperitoneal dissection.

INIITIAL EXPERIENCE WITH STEERABLE INSTRUMENTATION IN HUMAN CADAVERIC MODELS WITH SIMULATED TUMOR TARGETS

TOPIC: Procedures TYPE: Original Investigations PURPOSE: Despite growing experience using advanced guided techniques, the diagnostic yield of bronchoscopy for peripheral pulmonary lesions remains suboptimal, particularly for lesions which are adjacent to peripheral bronchi. While recent publications have focused on improving bronchoscopic reach, access and precision in the lung periphery, few have addressed significant modifications to the instrumentation used to obtain biopsies. This exercise was performed to evaluate two novel, steerable instruments within human cadaveric lungs with simulated tumor targets. Instrument assessment included the ability of both instruments to access simulated tumor targets in all lobes of the lung, as well as to reposition instruments within tumor targets. METHODS: Artificial tumor targets were placed in all lobes of the lungs of two human cadaver torsos which were intubated, ventilated and underwent CT scanning. Bronchoscopists utilized a large caliber bronchoscope (BF-1TH190, Olympus, Tokyo, Japan) and steerable guide sheath (2.7mm OD)(SerpeX Medical, Santa Clara, CA) by advancing, rotating and articulating the distal end of the guide sheath towards the targeted lesion using fluoroscopic guidance and a reference CT scan. Radial probe endobronchial ultrasound (UM S20-17S, Olympus Tokyo, Japan) was used to confirm lesion localization prior to performing transbronchial needle aspiration (Periview Flex, Olympus, Tokyo, Japan) and transbronchial biopsy (Precisor Broncho Forceps, ConMed, Utica, NY). Following this, a standard diagnostic bronchoscope (BF-H190, Olympus, Tokyo, Japan) was used to advance a steerable needle (1.8mm OD)(SerpeX Medical, Santa Clara, CA) towards the same targeted lesions using insertion, rotation and articulation of the distal tip. RESULTS: Both the steerable sheath and steerable needle were successfully placed within simulated tumor targets in all lobes of two cadaveric lungs with diagnostic biopsy material obtained from all lobes. Additionally, manipulation of the distal end of the steerable sheath and steerable needle was successfully used to reposition each tool within different locations of the same lesion. CONCLUSIONS: This is an initial reporting of two fully articulating, steerable instruments designed to assist with bronchoscopic biopsy of peripheral lung lesions. In this exercise both instruments were successfully positioned within tumor targets in all lobes of two human cadaveric lungs. Additionally, articulation and rotation of the distal end of each of these instruments successfully repositioned biopsy instruments within different locations of targeted lesions. CLINICAL IMPLICATIONS: Steerable instrumentation may improve the bronchoscopist's ability to place biopsy tools within targeted peripheral lesions, thereby potentially improving diagnostic yield, particularly for lesions that are positioned adjacent to peripheral bronchi. DISCLOSURES: Consultant relationship with Serpex Please note: 2020-2021 Added 04/24/2021 by Alexander Chen, source=Web Response, value=Consulting fee Removed 04/27/2021 by Alexander Chen, source=Web Response Investigator relationship with Olympus Please note: 2020-2021 Added 04/27/2021 by Alexander Chen, source=Web Response, value=Grant/Research Support Consultant relationship with Boston Scientific Please note: 2020-2021 Added 05/10/2021 by Alexander Chen, source=Web Response, value=Consulting fee Consultant relationship with Olympus America, Inc Please note: 1/2019 to current Added 04/28/2021 by Andrew Haas, source=Web Response, value=Consulting fee Consultant relationship with Serpex Medical Please note: 1/2020 to current Added 04/28/2021 by Andrew Haas, source=Web Response, value=Consulting fee DSMB, consultant relationship with Novocure, Inc Please note: 1/2019 to current Added 04/28/2021 by Andrew Haas, source=Web Response, value=Consulting fee Consultant relationship with Olympus America Please note: 1/2019 to current Added 04/28/2021 by Andrew Haas, source=Web Response, value=Consulting fee No relevant relationships by Michael Machuzak, source=Web Response

Feasibility of fresh frozen human cadavers as a research and training model for endovascular image guided interventions.

To describe the feasibility of a fresh frozen human cadaver model for research and training of endovascular image guided procedures in the aorta and lower extremity. The cadaver model was constructed in fresh frozen human cadaver torsos and lower extremities. Endovascular access was acquired by inserting a sheath in the femoral artery. The arterial segment of the specimen was restricted by ligation of collateral arteries and, in the torsos, clamping of the contralateral femoral artery and balloon occlusion of the supratruncal aorta. Tap water was administered through the sheath to create sufficient intraluminal pressure to manipulate devices and acquire digital subtraction angiography (DSA). Endovascular cannulation tasks of the visceral arteries (torso) or the peripheral arteries (lower extremities) were performed to assess the vascular patency of the model. Feasibility of this model is based on our institute's experiences throughout the use of six fresh frozen human cadaver torsos and 22 lower extremities. Endovascular simulation in the aortic and peripheral vasculature was achieved using this human cadaver model. Acquisition of DSA images was feasible in both the torsos and the lower extremities. Approximately 84 of the 90 target vessels (93.3%) were patent, the remaining six vessels showed signs of calcified steno-occlusive disease. Fresh frozen human cadavers provide a feasible simulation model for aortic and peripheral endovascular interventions, and can potentially reduce the need for animal experimentation. This model is suitable for the evaluation of new endovascular devices and techniques or to master endovascular skills.

Referencing the pectoralis major tendon for humeral stem height placement in reverse shoulder arthroplasty for fracture

BackgroundProximal humerus fractures remain a challenging problem, and reverse total shoulder arthroplasty (RSA) has demonstrated reliable outcomes in fracture applications. Despite this, guidelines for placement of the humeral component are lacking. MethodsTwelve cadaveric shoulders (6 cadaveric torsos) were utilized. An onlay RSA stem was placed with the lateral potion of the humeral cup positioned at the level of the greater tuberosity. Measurements were taken from the top of the pectoralis major tendon to the top of the humeral stem. A separate computer-aided analysis was conducted analyzing the height of an RSA humeral stem and an RSA humeral stem with a cup using values extrapolated from prior data. ResultsThe average distance from the top of the pectoralis to the top of the humeral stem was 4.0 cm (3.4 cm to 4.8 cm) with a standard deviation of 4.1. The humeral cup added an average of 9.1 mm. Computer-aided design data demonstrated the average height of the humeral stem was 3.9 cm above the superior aspect of the pectoralis tendon, and the average height with the humeral cup added was 4.8 cm. ConclusionBoth the cadaveric and computer-aided design data demonstrated a similar height for both the distances from the superior portion of the pectoralis to the superior aspect of an onlay RSA stem and the humeral cup. The measurement from the humeral cup may allow for translational use with inlay RSA humeral stems. This study demonstrates the superior border of the pectoralis major tendon to be a reliable landmark in RSA humeral stem placement. Level of evidenceLevel IV; Cadaveric Study

Systemic Lupus Erythematosus Does Not Worsen Outcomes of Patients Admitted for Heart failure Exacerbation: Analysis of the National Inpatient Sample

Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium.We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries.Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 females, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition, we measured the width of the different bone layers.The mean length of the hourglass shaped iliac pillar was 107.04 mm with a mean width of 17.0 mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00 mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16 mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o’clock. The smallest mean diameter of the cancellous bone was 7.5 mm ± 2.0.The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway.Anatomical descriptive study.

Do Rheumatoid Arthritis Patients Have Worse Outcomes When Hospitalized for Heart Failure Exacerbation?

Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium.We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries.Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 females, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition, we measured the width of the different bone layers.The mean length of the hourglass shaped iliac pillar was 107.04 mm with a mean width of 17.0 mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00 mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16 mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o’clock. The smallest mean diameter of the cancellous bone was 7.5 mm ± 2.0.The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway.Anatomical descriptive study.

A cadaveric precision and accuracy analysis of augmented reality-mediated percutaneous pedicle implant insertion.

Augmented reality-mediated spine surgery (ARMSS) is a minimally invasive novel technology that has the potential to increase the efficiency, accuracy, and safety of conventional percutaneous pedicle screw insertion methods. Visual 3D spinal anatomical and 2D navigation images are directly projected onto the operator's retina and superimposed over the surgical field, eliminating field of vision and attention shift to a remote display. The objective of this cadaveric study was to assess the accuracy and precision of percutaneous ARMSS pedicle implant insertion. Instrumentation was placed in 5 cadaveric torsos via ARMSS with the xvision augmented reality head-mounted display (AR-HMD) platform at levels ranging from T5 to S1 for a total of 113 total implants (93 pedicle screws and 20 Jamshidi needles). Postprocedural CT scans were graded by two independent neuroradiologists using the Gertzbein-Robbins scale (grades A-E) for clinical accuracy. Technical precision was calculated using superimposition analysis employing the Medical Image Interaction Toolkit to yield angular trajectory (°) and linear screw tip (mm) deviation from the virtual pedicle screw position compared with the actual pedicle screw position on postprocedural CT imaging. The overall implant insertion clinical accuracy achieved was 99.1%. Lumbosacral and thoracic clinical accuracies were 100% and 98.2%, respectively. Specifically, among all implants inserted, 112 were noted to be Gertzbein-Robbins grade A or B (99.12%), with only 1 medial Gertzbein-Robbins grade C breach (> 2-mm pedicle breach) in a thoracic pedicle at T9. Precision analysis of the inserted pedicle screws yielded a mean screw tip linear deviation of 1.98 mm (99% CI 1.74-2.22 mm) and a mean angular error of 1.29° (99% CI 1.11°-1.46°) from the projected trajectory. These data compare favorably with data from existing navigation platforms and regulatory precision requirements mandating that linear and angular deviation be less than 3 mm (p < 0.01) and 3° (p < 0.01), respectively. Percutaneous ARMSS pedicle implant insertion is a technically feasible, accurate, and highly precise method.

The Shoulder Trans-pectoralis Arthroscopic Portal Is a Safe Approach to the Arthroscopic Latarjet Procedure: A Cadaveric Analysis

To assess the proximity of neurovascular structures in a layered approach during medial portal placement and determine standardized measurements for establishing a portal medial to the coracoid used in arthroscopic Latarjet-type procedures. Twelve shoulders (6 right and 6 left) in 6 fresh frozen cadaveric torsos were mounted in the modified beach-chair position. A standard posterior portal and 3 anterior portals-central, lateral, and medial-were used. A long spinal needle was placed along the path of the medial portal to the lateral tip of the coracoid, superficial to the conjoined tendon and pectoralis minor. A second long spinal needle was directed toward the medial base of the coracoid, penetrating the pectoralis minor. Superficial and deep plane dissections were performed, and distances to surrounding neurovascular structures were recorded. In the superficial plane, the cephalic vein and lateral pectoral nerve were located a mean distance (± standard deviation) of 4.6 ± 1.9 mm and 9.4 ± 2.6 mm from the spinal needle, respectively. In the deep plane, the axillary nerve was 24.9 ± 7.4 mm from the needle; the lateral cord of the brachial plexus, 25.5 ± 8.1 mm; the axillary artery, 34.1 ± 6.0 mm; and the musculocutaneous nerve, 42.2 ± 9.2 mm. The portal was consistently established 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the coracoid, which was a minimum distance of 10 mm to the lateral pectoral nerve. In a cadaveric model, the creation of a medial trans-pectoralis major portal used in the arthroscopic Bankart-Bristow-Latarjet procedure can avoid compromise of vital neurovascular structures, alleviating concerns of creating a portal medial to the coracoid. Portal placement 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the palpable tip of the coracoid process may be a safe approach to perform the arthroscopic Bankart-Bristow-Latarjet procedure. Creation of a portal medial to the level of the coracoid may pose a risk to neurovascular structures. This cadaveric study establishes a working zone for medial trans-pectoralis portal placement, which avoids vital neurovascular structures, and provides standardized measurements for establishing this portal for use in the arthroscopic Bankart-Bristow-Latarjet procedure.

151. A cadaveric precision and accuracy analysis of augmented reality mediated percutaneous pedicle implant insertion

BACKGROUND CONTEXT Augmented reality mediated spine surgery (ARMSS) is a minimally invasive novel technology that has the potential to increase the efficiency, accuracy, and safety of conventional percutaneous pedicle screw insertion methods. Visual 3-dimensional (3D) spinal anatomic and 2-dimensional (2D) navigation images are directly projected onto the operators’ retina and superimposed over the surgical field eliminating field of vision and attention shift to a remote display. The objective of this study was to assess the accuracy and precision of percutaneous ARMSS pedicle implant insertion. PURPOSE To assess the clinical accuracy and technical precision of head-mounted display (HMD) augmented reality (AR) assisted percutaneous pedicle screw insertion. STUDY DESIGN/SETTING Cadaveric accuracy and precision study. PATIENT SAMPLE Not applicable. OUTCOME MEASURES Not applicable. METHODS Five cadaveric torsos were ARMSS instrumented with the xvision AR-HMD platform (Augmedics; Chicago, IL) at levels ranging from T5 to S1 for a total of 113 total implants comprised of 93 pedicle screws and 20 jamshidi needles. Postprocedural computed tomography (CT) scans were graded by two independent neuroradiologists using the Gertzbein scale (GS A-E) for clinical accuracy. Technical precision was calculated via superimposition analysis employing the Medical Image Interaction Toolkit (MITK; Heidelberg, Germany) to yield angular trajectory (°) and screw tip (mm) linear deviation from the virtual pedicle screw position vs the actual pedicle screw position on post-procedural CT imaging. RESULTS The overall implant insertion clinical accuracy achieved was 99.1%. Sacro-lumbar and thoracic clinical accuracy was 100% and 98.3%, respectively. Specifically, among all implants inserted, 112 were noted to be GS A or B (99.12%) with only 1 medial GS C breach (>2 mm pedicle breach) in a thoracic pedicle at T9. Precision analysis of inserted pedicle screws yielded a mean screw tip linear deviation of 1.98 mm [99% CI:1.74 – 2.21 mm] and a mean angular error of 1.29° [99% CI:1.11° – 1.46°] from the projected trajectory. The latter data compare favorably to existing navigation platforms and regulatory precision requirements mandating that linear and angular deviation be below 3 mm (p CONCLUSIONS Percutaneous ARMSS pedicle implant insertion is a technically feasible, accurate, and highly precise method. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

L’isthme iliaque — Définition d’une voie pour la fixation osseuse interne et externe

BackgroundIncreasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium. HypothesisWe aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries. MethodsTwenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 females, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition, we measured the width of the different bone layers. ResultsThe mean length of the hourglass shaped iliac pillar was 107.04mm with a mean width of 17.0mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o’clock. The smallest mean diameter of the cancellous bone was 7.5mm±2.0. ConclusionThe iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway. Level of evidenceAnatomical descriptive study.