Unembalmed Cadavers Research Articles

Comparison of Dye Spread Pattern and Nerve Involvement between Suprainguinal and Infrainguinal Fascia Iliaca Blocks with Different Injectate Volumes: A Cadaveric Evaluation.

Background and Objectives: Fascia iliaca compartment block (FICB) is an effective and relatively safe technique in perioperative pain management for hip surgery. However, blockade of the obturator nerve (ON) using this technique remains controversial. This study aimed to compare dye spread patterns and nerve involvement in the suprainguinal FICB (S-FICB) and infrainguinal FICB (I-FICB) approaches using different volumes of dye. Materials and Methods: Following randomization, 6 S-FICBs and 6 I-FICBs were performed on the left or right sides of 6 unembalmed cadavers. For each block, 30 mL or 60 mL of dye solution was injected. The extent of dye spreading and the staining pattern in the lumbar plexus branches were investigated using anatomical dissection. Results: Twelve injections were successfully completed. The lateral femoral cutaneous nerve (LFCN) and femoral nerve (FN) were consistently stained in all injections. Extended dye spread toward lumbar plexus branches was observed volume-dependently in S-FICBs. However, I-FICBs with an increased volume only showed dye spreading in the caudad direction limited to within the fascia iliaca. When 30 mL of dye was used, the ON was not stained with either approach. A stained ON was only observed in S-FICBs when 60 mL of dye was used. Conclusions: In this cadaveric evaluation, the ON was not stained in either FICB approach with the volume of injectate commonly used in clinical practice. The S-FICBs but not I-FICBs using a high volume of injectate resulted in extended spreading to the lumbar plexus branches.

Anatomical evaluation of the superficial parasternal intercostal plane block

Background and objectivesFew cadaveric studies have evaluated the dye spread with superficial parasternal intercostal plane (SPIP) blocks. In this study, we examined the dye spread of an ultrasound-guided SPIP block...

Accuracy of Instrumented Mouthguards During Direct Jaw Impacts Seen in Boxing.

Measuring head kinematics data is important to understand and develop methods and standards to mitigate head injuries in contact sports. Instrumented mouthguards (iMGs) have been developed to address coupling issues with previous sensors. Although validated with anthropomorphic test devices (ATDs), there is limited post-mortem human subjects (PMHS) data which provides more accurate soft tissue responses. This study evaluated two iMGs (Prevent Biometrics (PRE) and Diversified Technical Systems (DTS) in response to direct jaw impacts. Three unembalmed male cadaver heads were properly fitted with two different boil-and-bite iMGs and impacted with hook (4m/s) and uppercut (3m/s) punches. A reference sensor (REF) was rigidly attached to the base of the skull, impact kinematics were transformed to the head center of gravity and linear and angular kinematic data were compared to the iMGs including Peak Linear Acceleration, Peak Angular Acceleration, Peak Angular Velocity, Head Injury Criterion (HIC), HIC duration, and Brain Injury Criterion. Compared to the REF sensor, the PRE iMG underpredicted most of the kinematic data with slopes of the validation regression line between 0.72 and 1.04 and the DTS overpredicted all the kinematic data with slopes of the regression line between 1.4 and 8.7. While the PRE iMG was closer to the REF sensor compared to the DTS iMG, the results did not support the previous findings reported with use of ATDs. Hence, our study highlights the benefits of using PMHS for validating the accuracy of iMGs since they closely mimic the human body compared to any ATD's mandible.

Erector spinae plane infiltration and anterior rami of spinal nerve: a cadaveric study

BackgroundThe erector spinae plane block (ESP block) is frequently employed for thoracic, abdominal, and spinal surgeries, yet its precise mechanism of action remains a subject of debate. While initially postulated...

Biofidelity and Limitations of Instrumented Mouthguard Systems for Assessment of Rigid Body Head Kinematics.

Instrumented mouthguard systems (iMGs) are commonly used to study rigid body head kinematics across a variety of athletic environments. Previous work has found good fidelity for iMGs rigidly fixed to anthropomorphic test device (ATD) headforms when compared to reference systems, but few validation studies have focused on iMG performance in human cadaver heads. Here, we examine the performance of two boil-and-bite style iMGs in helmeted cadaver heads. Three unembalmed human cadaver heads were fitted with two instrumented boil-and-bite mouthguards [Prevent Biometrics and Diversified Technical Systems (DTS)] per manufacturer instructions. Reference sensors were rigidly fixed to each specimen. Specimens were fitted with a Riddell SpeedFlex American football helmet and impacted with a rigid impactor at three velocities and locations. All impact kinematics were compared at the head center of gravity. The Prevent iMG performed comparably to the reference system up to ~ 60g in linear acceleration, but overall had poor correlation (CCC = 0.39). Prevent iMG angular velocity and BrIC generally well correlated with the reference, while underestimating HIC and overestimating HIC duration. The DTS iMG consistently overestimated the reference across all measures, with linear acceleration error ranging from 10 to 66%, and angular acceleration errors greater than 300%. Neither iMG demonstrated consistent agreement with the reference system. While iMG validation efforts have utilized ATD testing, this study highlights the need for cadaver testing and validation of devices intended for use in-vivo, particularly when considering realistic (non-idealized) sensor-skull coupling, when accounting for interactions with the mandible and when subject-specific anatomy may affect device performance.

Singular entry point technique for forehead and temple filler augmentation: Anatomical and clinical perspectives.

The depressed volume of the forehead and temple is resolved by filler injection. However, the current method has the potential to cause pain and side effects in patients, depending on the skill of the clinician. Therefore, this study proposes a new method for safer and simpler injection using only one injection entry point. Using the novel injection method, the filler was injected into the forehead and temple regions in three unembalmed cadavers and two healthy Korean volunteers. The cannula and filler locations were identified using dissection, ultrasonography, and three-dimensional (3D) scanning. Ultrasonographic images and dissection results showed that the filler injected into the cadavers was in the target layer. The cannula and filler were located on the layer as the supraperiosteal layer on the forehead and the supra deep temporal fascia layer in the temple. Finally, 3D scanning images showed that the filler was injected precisely and effectively into the forehead and temples of the volunteer who underwent the procedure. This method can reduce pain and minimize externally visible wounds caused by injections. The injected filler was naturally connected from the forehead to the temple and maintained for around 3 months. Additionally, it is possible to inject fillers into the forehead and temple at a constant and safe depth without requiring specific skills. It is expected that this method will become a universal method because it minimizes the burden on both patients and clinicians.

Ultrasound guided quadro-iliac plane block: another novel fascial plane block.

We report a novel block technique aimed to provide lumbosacral, abdominal, and hip analgesia: The quadro-iliac plane (QIP) block. A cadaveric examination that evaluates the spread of QIP block. Cadaver laboratory. One unembalmed cadaver. Bilateral ultrasound-guided QIP blocks on cadavers with 40 mL of methylene blue %0.5 each side. Dye spread in cadaver. There was staining in the deep interfascial plane of the erector spinae muscles. Extensive staining of the interfascial plane corresponding to the posterior aspect of the quadratus lumborum muscle (QLM) was observed. There was extensive staining on the anterior surface of the QLM. There was spread of dye traversing along the transversalis fascia and significantly infiltrating retroperitoneal fat tissue. Bilateral staining of the ilioinguinal and iliohypogastric nerves was observed. On the right, there was minimal staining over the subcostal nerve. There was dye present bilaterally within the deep regions of the transverse processes. The lumbar plexus was stained on both sides. The local anesthetic applied from a place where the QLM reaches its largest volume and the fascial plane creates a closed gap in the caudal area may exhibit a more rounded and extensive spread.Quadro-iliac plane block, involves the administration of local anesthetic to the posterior aspect of the QLM at its origin from the iliac crest. According to our cadaver study, this technique may be a promising option for alleviating acute and chronic pain in the lumbosacral, lower abdominal, and hip regions.

No evidence of fascicular injury following a low-volume intraneural injection of the median nerve: a cadaveric study

BackgroundThe test dose or hydrolocation technique allows rapid detection of spread location. Though its primary aim is to enhance safety in peripheral nerve blocks, evidence on the potential risks of...

Axillary arch (of Langer): A large-scale dissection and simulation study based on unembalmed cadavers of body donors.

Connective or muscular tissue crossing the axilla is named axillary arch (of Langer). It is known to complicate axillary surgery and to compress nerves and vessels transiting from the axilla to the arm. Our study aims at systematically researching the frequency, insertions, tissue composition and dimension of axillary arches in a large cohort of individuals with regard to gender and bilaterality. In addition, it aims at evaluating the ability of axillary arches to cause compression of the axillary neurovascular bundle. Four hundred axillae from 200 unembalmed and previously unharmed cadavers were investigated by careful anatomical dissection. Identified axillary arches were examined for tissue composition and insertion. Length, width and thickness were measured. The relation of the axillary arch and the neurovascular axillary bundle was recorded after passive arm movements. Twenty-seven axillae of 18 cadavers featured axillary arches. Macroscopically, 15 solely comprised muscular tissue, six connective tissue and six both. Their average length was 79.56 mm, width 7.44 mm and thickness 2.30 mm. One to three distinct insertions were observed. After passive abduction and external rotation of the arm, 17 arches (63%) touched the neurovascular axillary bundle. According to our results, 9% of the Central European population feature an axillary arch. Approximately 50% of it bilaterally. A total of 40.74% of the arches have a thickness of 3 mm or more and 63% bear the potential of touching or compressing the neuromuscular axillary bundle upon arm movement.

Pelvis-Sacrum-Lumbar Spine Injury Characteristics From Underbody Blast Loading.

Combat-related injuries from improvised explosive devices occur commonly to the lower extremity and spine. As the underbody blast impact loading traverses from the seat to pelvis to spine, energy transfer occurs through deformations of the combined pelvis-sacrum-lumbar spine complex, and the time factor plays a role in injury to any of these components. Previous studies have largely ignored the role of the time variable in injuries, injury mechanisms, and warfighter tolerance. The objective of this study is to relate the time or temporal factor using a multi-component, pelvis-sacrum-lumbar spinal column complex model. Intact pelvis-sacrum-spine specimens from pre-screened unembalmed human cadavers were prepared by fixing at the superior end of the lumbar spine, pelvis and abdominal contents were simulated, and a weight was added to the cranial end of the fixation to account for torso effective mass. Prepared specimens were placed on the platform of a custom vertical accelerator device and aligned in a seated soldier posture. An accelerometer was attached to the seat platen of the device to record the time duration to peak velocity. Radiographs and computed tomography images were used to document and associate injuries with time duration. The mean age, stature, weight, body mass index, and bone density of 12 male specimens were as follows: 65 ± 11 years, 1.8 ± 0.01 m, 83 ± 13 kg, 27 ± 5.0 kg/m2, and 114 ± 21 mg/cc. They were equally divided into short, medium, and long time durations: 4.8 ± 0.5, 16.3 ± 7.3, and 34.5 ± 7.5 ms. Most severe injuries associated with the short time duration were to pelvis, although they were to spine for the long time duration. With adequate time for the underbody blast loading to traverse the pelvis-sacrum-spine complex, distal structures are spared while proximal/spine structures sustain severe/unstable injuries. The time factor may have implications in seat and/or seat structure design in future military vehicles to advance warfighter safety.

Upper limb neurodynamic mobilization disperses intraneural fluid in cervical nerve roots: A human cadaveric investigation

BackgroundCervical radiculopathy is a common cause of neck pain with resultant intraneural edema and impaired nerve function. One strategy to treat radiculopathy is neurodynamic mobilization (NDM); however, little is known about the effect of this treatment on nerve tissue fluid dynamics. ObjectiveInvestigate the impact of upper limb, median nerve-biased NDM on longitudinal intraneural fluid dispersion in the C5,C6,C7 nerve roots in un-embalmed cadavers. DesignIn situ repeated measures. MethodsHuman cadavers (n = 8) were dissected to expose and inject C5,C6,C7 cervical nerve roots with a dying agent. Initial longitudinal dye spread was recorded after dye spread stabilization. Cadavers were taken through 150 repetitions of upper limb, median nerve-biased NDM followed by dye spread re-measurement. Paired-samples t-tests with Bonferroni correction (α = 0.017) were used to compare pre-vs post-NDM dye spread measurements at C5,C6,C7 nerve roots; a one-way repeated measures ANOVA (α = 0.05) was used to examine differences between change scores for C5,C6,C7 nerve roots. ResultsMedian nerve-biased NDM resulted in significant intraneural longitudinal dye spread at C5 and C6 nerve roots of 0.6 ± 0.6 mm and 3.4 ± 3.9 mm, respectively (p < 0.014). Dye spread was not significant at C7 nerve root (0.4 ± 0.7 mm). There was no between root difference in change of longitudinal dye spread between C5, C6, and C7 nerve roots. ConclusionsThe results of this study show median nerve-biased NDM produced internal fluid movement within C5 and C6 cervical nerve roots. Results provide insight regarding possible mechanism of action and feasibility of NDM in treatment of patients with cervical radiculopathy.

Machine learning-directed electrical impedance tomography to predict metabolically vulnerable plaques.

The characterization of atherosclerotic plaques to predict their vulnerability to rupture remains a diagnostic challenge. Despite existing imaging modalities, none have proven their abilities to identify metabolically active oxidized low-density lipoprotein (oxLDL), a marker of plaque vulnerability. To this end, we developed a machine learning-directed electrochemical impedance spectroscopy (EIS) platform to analyze oxLDL-rich plaques, with immunohistology serving as the ground truth. We fabricated the EIS sensor by affixing a six-point microelectrode configuration onto a silicone balloon catheter and electroplating the surface with platinum black (PtB) to improve the charge transfer efficiency at the electrochemical interface. To demonstrate clinical translation, we deployed the EIS sensor to the coronary arteries of an explanted human heart from a patient undergoing heart transplant and interrogated the atherosclerotic lesions to reconstruct the 3D EIS profiles of oxLDL-rich atherosclerotic plaques in both right coronary and left descending coronary arteries. To establish effective generalization of our methods, we repeated the reconstruction and training process on the common carotid arteries of an unembalmed human cadaver specimen. Our findings indicated that our DenseNet model achieves the most reliable predictions for metabolically vulnerable plaque, yielding an accuracy of 92.59% after 100 epochs of training.

Thiel embalming method used for anatomy dissection as an educational tool in teaching human anatomy, in research, and in training in comparison of different methods for long term preservation.

The use of human cadavers is beneficial in teaching gross human anatomy, training, and development in medicine. Fresh-frozen cadavers initially exhibit natural colour, tenderness, and flexibility. They also present innumerable difficulties, including the requirement of freezers for storage and a few weeks' work time because of fast decay. The risk of infection is also significant. A possible choice for fresh-frozen cadavers is embalmed cadavers. The requested characteristic needed for successful embalming is acceptable long-term structural preservation of organs and tissues with minimal deformity and prevention of outward aspects. Scientists are trying to develop an ideal embalming solution to preserve the human body. Such a solution renders the flexibility of internal organs, preventing dryness, and reducing fungal or bacterial growth. Cadavers should be in a condition comparable to that of an unembalmed cadaver, and the chemicals used in the solution should not be harmful to persons during manipulation. The promising results have been obtained by the use of different embalming techniques by many faculties of medicine as a tool to enhance the teaching of anatomy to students.

Deep parasternal intercostal plane nerve block: an anatomical study

IntroductionThe superficial and deep parasternal intercostal plane (DPIP) blocks are two new blocks for thoracic pain. There are limited cadaveric studies evaluating the dye spread with these blocks. In this...

Adductor canal block techniques do not lead to involvement of sciatic nerve branches: a radiological cadaveric study

IntroductionLow and high volume mid-thigh (ie, distal femoral triangle) and distal adductor canal block approaches are frequently applied for knee surgical procedures. Although these techniques aim to contain the injectate...

Pelvic Floor Pressures Differ Based on Location in the Pelvis and Body Position: A Cadaver Mode

The pelvic floor is a bowl-shaped complex of multiple muscles and fascia, which functions to support the pelvic organs, and it aids in controlling continence. In pelvic floor disease, this complex becomes weakened or damaged leading to urinary, fecal incontinence, and pelvic organ prolapse. It is unclear whether the position of the body impacts the forces on the pelvic floor. The primary objective of this work is to measure force applied to the pelvic floor of a cadaver in sitting, standing, supine, and control positions. The secondary objective is to map the forces across the pelvic floor. An un-embalmed female cadaver without pelvic floor dysfunction was prepared for pelvic floor pressure measurement using a pressure sensory array placed on top of the pelvic floor, and urodynamic catheters were placed in the hollow of the sacrum, the retropubic space, and at the vaginal apex. Pressure measurements were recorded with the cadaver in the supine position, sitting cushioned without external pelvic floor support, and standing. Pressure array data were analyzed along with imaging of the cadaver. Together, these data were mapped into a three-dimensional reconstruction of the pressure points in pelvic floor and corresponding pelvic organs. pressures were higher at the symphysis than in the hollow of the sacrum in the standing position. Pressure array measurements were lowest in the standing position and highest in the sitting position. Three-dimensional reconstruction confirmed the location and accuracy of our measurements. The findings of increased pressures behind the symphysis are in line with the higher incidence of anterior compartment prolapse. Our findings support our hypothesis that the natural shape and orientation of the pelvis in the standing position shields the pelvic floor from downward forces of the viscera.

Rembrandt’s Anatomy Lesson of Dr. Tulp Revisited: Advancements in Teaching Anatomy and Neurobiology in an Integrated Medical Curriculum in the 21st Century.

The recent challenges in anatomy and neurobiology education in medical curricula have imposed a curricular redevelopment in delivery and content, incorporating modules in virtual anatomy and neurobiology, didactic lecture and enhanced cadaveric dissection in a state-of-the-art teaching and learning environment. The combined approach engaged active student participation at each phase of the course, incorporated clinical perspectives, emphasized valuable diagnostic and surgical techniques and procedures, and minimized noxious exposure to formaldehyde by using unembalmed cadavers in a laminar airflow environment. Finally, the objectives of emphasizing the importance of proficiency in anatomy knowledge in clinical medicine were accomplished well within the allocated one semester time frame, in a timely, cost and resource effective manner, and with demonstration of competency to standard during post laboratory examinations.

Anatomic relationships of the clitoral body, bulbs of the vestibule, and urethra

Although recent studies have enhanced our understanding of the anatomy of the clitoris and its somatic innervation, less emphasis has been placed on the anatomic relationships of the clitoris to its surrounding structures. This study aimed to further characterize the gross and histologic relationships of the clitoris, vestibular bulbs, and urethra. Detailed dissections were performed in 30 unembalmed female cadavers. In 23 specimens, gross dissections were performed, and relationships of the clitoris, vestibular bulbs, and urethra were annotated. Histologic evaluation was performed in 7 specimens, in which tissues were harvested within 24 hours from death. Descriptive statistics were used for data analyses. The clitoral body consisted of 2 components, the proximal body and the distal body. The distal body was oriented ≤90° from the proximal body, forming an outer and inner angle at the inflection point. A "septumlike" arrangement of fibroconnective and vascular tissues was noted between the inner angle of the clitoral body and the urethra. Neurovascular bundles coursed laterally along the clitoral body and the surfaces of the crura and vestibular bulbs. The vestibular bulbs approached each other over the ventral surface of the urethra, at the commissure of the vestibular bulbs. Each bulb was separated by fibrous tissue and did not merge along the midline. The vestibular bulbs approximated the clitoral body, but the erectile tissue of the vestibular bulbs was separated from the corpora cavernosa of the clitoral body by the tunica albuginea. The erectile tissue of the vestibular bulbs abutted the ventrolateral walls of the urethra but was separated from the urethral mucosa by an indiscrete layer of erectilelike tissue with dense stroma. This study provided gross and histological confirmation of the relationships of the clitoris, vestibular bulbs, and urethra. Detailed knowledge of the anatomy of the clitoris is crucial for reducing surgical complications associated with periclitoral and distal urethral procedures, which may adversely affect sexual arousal and sexual function.

Evaluating two approaches to the erector spinae plane block: an anatomical study

Background and objectivesStudies show variable spread with thoracic erector spinae plane (ESP) injections. Injection sites vary from lateral end of the transverse process (TP) to 3 cm from the spinous...

Serratus Posterior Superior Intercostal Plane Block: A Technical Report on the Description of a Novel Periparavertebral Block for Thoracic Pain.

Background and objective We report a novel block technique aimed to provide thoracic analgesia: the serratus posterior superior intercostal plane (SPSIP) block. Design A cadaveric evaluation along with aretrospective case series evaluating the potential analgesic effect of the SPSIP block. This study included one unembalmed cadaver and five patients. Interventions Bilateral ultrasound-guided SPSIP block was used on cadavers with 30 mL of methylene blue 0.5% on each side; single-injection SPSIP blocks were used in patients. To measure results, dye spread was used in the cadaver, and dermatomal/pain score evaluation was used in patients. Main results Anatomical investigation in one unembalmed cadaver shows that its mechanism of action covers the rhomboid major muscle, erector spinae muscle, the deep fascia of the subscapularis/serratus anterior muscles, and intercostal nerves. In our patients, SPSIP resulted in an almost complete sensory block in the back of the neck, shoulder, and hemithorax. Conclusion Our cadaveric study shows extensive dye spread from C7 to T7. Patients who were administrated SPSIP block reported consistent dermatomal blockade from C3 to T10 levels of the hemitorax. The SPSIP block seems to be a safe, simple, and effective technique for thoracic analgesia.