Neonatal Cadavers Research Articles

Topography and dimensions of the auditory tube at the end of the fetal period

Introduction. Otitis media in premature newborns and term newborns is a serious problem due to the immaturity of the organs and systems of these children and the difficulty of their adaptation. This often leads to the development of pathological changes in the hearing organ and the need for surgical intervention. The aim - to find out the topographic and anatomical features of the auditory tube at the end of the fetal period to improve technologies and the adequacy of surgical treatment. Material and methods. The study was performed on 35 human fetuses of 231.0-375.0 mm parietococcygeal length (PCL) and 11 neonatal cadavers. In the course of the study the following methods were used: thin dissection of the middle ear and adjacent areas under the control of a binocular loupe; macro- and microscopy; morphometry; macro photography with digital camera "OLIMPUS μ 1000 All-weather 10.0 MPix". Results. It has been established that the size and shape of the auditory tube in premature babies do not have definitive dimensions and its location differs from that in term newborns. The pharyngeal openings of the auditory tubes are located at the level of the hard palate, and in term newborns - above the level of the hard palate. The tympanic openings from the lower part of the anterior wall of the tympanic cavity in fetuses of the seventh month of intrauterine growth completely move to its upper part and open into the supratympanic space in fetuses of the tenth month. Conclusions. The defined features of the development of the auditory tube at the end of the fetal period are important for the improvement of technologies and the adequacy of surgical treatment and manipulations in premature babies and term newborns. The research was carried out in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committee of the institution indicated in the work. No conflict of interests was declared by the authors.

The anatomical location of the great saphenous vein at the thigh and ankle: a neonatal cadaver study

Providing critically ill neonatal patients with parenteral nutrition, medication, fluids, and access to blood sampling is essential in intensive care units. One option for blood sampling is the great saphenous vein within the proximal thigh, and near the medial malleolus in neonates via ‘conventional’ landmark and ultrasound techniques. Practitioners in many countries still use the traditional landmark approach to locate the great saphenous vein in neonates, regardless of access to ultrasound. We aim to provide measurements that accurately describe the anatomy of the great saphenous vein in neonates to aid in cannulation success. The great saphenous vein was exposed in the proximal thigh and near the medial malleolus by reflecting the skin in 31 and 30 formalin-fixed neonate cadavers, respectively. Pins were placed at essential bony landmarks and soft tissue structures. The termination of the great saphenous vein within the proximal thigh can be located 6.8 ± 1.5 mm inferior to the inguinal ligament. The average shortest distance from the medial malleolus to the great saphenous vein was 4.3 mm, 2.0 mm anterior, and 3.1 mm superiorly. The diameter of the great saphenous vein in the proximal thigh and at the medial malleolus ranged between 1.4 mm and 1.6 mm, and 0.9 mm and 1.1 mm, respectively with a 95% confidence level. Our results provide a more accurate description to gain venous access through the great saphenous vein. However, if available, ultrasound should be used to locate and confirm the diameter of the great saphenous vein in the lower limb.

Anatomical analysis of Sedillot's triangle as a reliable landmark for insertion of central venous catheters in neonates using a central approach

IntroductionSurgeons employ central venous catheterization as a therapeutic or preventive measure in the pediatric population. These catheters are introduced into the internal jugular, subclavian, or femoral veins using the central approach, involving the insertion of the needle into the apex of Sedillot's triangle, a well-defined anatomical reference point. Using a neonatal sample, this study ascertained the precise positioning of the internal jugular vein to evaluate its suitability as a central venous catheter insertion site. We also determined the location of the vein in relation to Sedillot's triangle. Materials and methodsNineteen formalin-fixed neonatal cadavers, encompassing both the left and right sides of the neck region (totaling 38 sides), were dissected to expose the underlying soft tissues and neurovascular structures. Thereafter, the three boundaries of Sedillot's triangle were identified, demarcated, and measured. The internal jugular vein's position within Sedillot's triangle was meticulously recorded, and the diameter of the vein was measured. ResultsAmong the 38 sides examined, only three exhibited fully formed triangles, with most of the samples featuring a groove instead. When the needle was placed at the apex of Sedillot's triangle (or within the groove), the needle consistently accessed the internal jugular vein only 65.8% of the time. In 23.7% of cases, the apex was observed lateral to the internal jugular vein, and in 10.5% of cases, the apex was positioned medially. ConclusionThe apex of Sedillot's triangle is an unreliable anatomical landmark for the insertion of central venous catheters in neonates. Caution should be exercised when employing this landmark in the absence of ultrasound guidance.

A global perspective on embryological and fetal collections: Where to from here?

Human fetal and embryos collections (FECs) peaked in the late 19th century, an era before informed consent, and hence have unclear provenance. These collections are not only historical artifacts, but prized resources for education and research. This study aimed to determine, via a narrative review, the present location, status, and profile of reported human fetal and embryonic collections. Twenty-seven articles that reported on collections appropriate to the study were selected from an initial search pool of 120 articles. The reported collections were in: Australia (n=1), Germany (n=6), Japan (n=1), Spain (n=1), and the United States (n=5). The largest collection is reported to contain 45,000 prenatal remains and the smallest, three remains. The purpose of establishing majority of the collections was for education and research. Eight collections contain both embryos and fetuses, one collection contained embryos, exclusively. Another collection contained only fetuses and one neonatal cadaver. The provenance, where mentioned, specified gynecologists and obstetricians as the main source of remains (n=5). Except for the Kyoto Collection, information regarding informed consent from the next-of-kin was lacking. This paper draws upon the three themes of purpose, provenance, and profile and highlights the need to establish agreed international guidelines for the most appropriate ethical and sustainable practice with respect to establishment, procurement of remains, access, and maintenance of these collections. Nine domains for these guidelines are recommended: consent, privacy, commercial gain, digital and emerging technologies, commemorations and memorials, destruction and disposal, dignity of donors, global database and collaboration, and sustainability.

Proximal tibial dimensions in a formalin-fixed neonatal cadaver sample: an intraosseous infusion approach.

Methods to administer intramedullary medication and fluid infusion in both adults and children date to the early twentieth century. Studies have shown that intraosseous access in the proximal tibia is ideal for resuscitation efforts as fewer critical structures are at risk, and neither is the blood flow to the lower limbs compromised. Insertion of a needle in children younger than 5years does have the risk to damage to the epiphyseal growth plate. Therefore, the aim of this study was to determine the ideal intraosseous insertion site distal to the epiphyseal growth plate in neonates. The samples consisted of both the left and right sides of 15 formalin-fixed neonatal cadavers. The dimensions were measured on the superior surfaces of each section, anteromedial border, cortical thickness, and medullary space. The most desirable location to gain vascular access is at 10mm inferior to the tibial tuberosity. The smallest cortical thickness (1.32mm), the largest medullary space (4.50mm), and the largest anteromedial surface (7.72mm) were observed at 10mm inferior to the tibial tuberosity. It is imperative that health care professionals are familiar with the osteological sites that could be safely used for an intraosseous infusion procedure.

Ex vivo mechanical testing of various suture patterns for use in tendon plating.

To determine the influence of suture patterns on resistance to gap formation after tendon plating STUDY DESIGN: Ex vivo study SAMPLE POPULATION: Suspensory ligament and superficial and deep digital flexor tendons harvested from 16 neonatal cadaver foal limbs. Each tendon/ligament from a given limb was randomly assigned to one of three treatment groups consisting of a 7-hole veterinary cuttable plate fixed with alternating simple interrupted, figure-8, or hybrid suture patterns. The constructs were distracted at a rate of 1.0 mm/s to failure, as determined by the formation of a 1 mm gap for initial failure and a 3 mm gap for ultimate failure. The mode of failure was also recorded. Constructs prepared with hybrid and figure-8 patterns sustained over 2× higher (p < .01) forces before gap formation compared to those prepared with a simple interrupted pattern. No difference was identified between tendons whose plate was secured with hybrid or figure-8 suture patterns. Mode of failure between groups did not differ. The figure-8 and hybrid patterns described herein improved the resistance to gap formation of plated tendons compared to an alternating simple interrupted pattern described previously. Figure-8 and hybrid patterns should be considered over simple interrupted patterns to improve resistance to gap formation in horses undergoing tendon plating.

The anatomical features of an ultrasound-guided erector spinae fascial plane block in a cadaveric neonatal sample.

Since its inception, the erector spinae plane block has been used for a variety of truncal surgeries with success in both adults and children. However, the anatomical features, route of spread, and dermatomal coverage are still not fully understood in a pediatric population. To identify the anatomical features of the erector spinae fascial plane space by replicating an erector spinae plane block in a fresh neonatal cadaveric sample. The primary aim was to determine the spread of the dye within the fascial plane, while the secondary aims were to determine whether the needle direction or entry site affected the spread. The block was replicated bilaterally using 0.1mL/kg of iodinated contrast dye in nine fresh unembalmed preterm neonatal cadavers. The dye was introduced under ultrasound guidance at vertebral level T5 and T8. Additionally, the needle was oriented cranial-caudal vs caudal-cranial to determine if the needle orientation influenced the spread of dye. The block was also replicated midway between the adjacent transverse processes as opposed to the lateral tip of the transverse process to determine the spread. From the total sample size, 14 "blocks" were successfully replicated, while 4 "blocks" were either incomplete or failed blocks. Contrast dye was found in the paravertebral, intercostal, and epidural spaces, including posteriorly over the neural foramina. Results revealed that the needle direction or entry site did not influence the spread within the fascial plane. Contrast material was found in the paravertebral, epidural, and intercostal spaces over an average of 5 vertebral levels when using 0.1mL/kg.

The extent of cranio-caudal spread within the erector spinae fascial plane space using computed tomography scanning in a neonatal cadaver.

The erector spinae plane block (ESP) is a novel approach for blockade of the spinal nerves in infants, children, and adults. Until recently, the gold standard for truncal procedures includes the paravertebral and epidural blocks. However, the exact mechanism by which this blockade is achieved is subject to debate. 2.3mL (1mL/kg) of iodinated contrast dye was injected bilaterally into the erector spinae fascial plane of a fresh unembalmed preterm neonatal cadaver (weighing 2.3kg), to replicate the erector spinae plane block and to track the cranio-caudal spread of the contrast dye using computed tomography. The "block" was performed at vertebral level T8 on the right-hand side and at vertebral level T10 on the left-hand side. Contrast dye was spread over three dermatomal levels from T6 to T9 on the right-hand side, while on the left-hand side, the spread was seen over four dermatomal levels from T9 to T11/12. Contrast dye also spread over the costotransverse ligament, into the paravertebral space and further lateral from the lateral border of the erector spinae muscle into the intercostal space. However, no spread was seen in the epidural space. The erector spinae plane block is a versatile technique that can be part of the multimodal postoperative analgesic strategy for truncal surgery. In this study, contrast material dye was tracked over four vertebral levels in the paravertebral space (suggesting an approximate volume of 0.5-0.6mL per dermatome).

A cadaveric study of the erector spinae plane block in a neonatal sample

BackgroundThe aim of this article was to provide a detailed description of the neonatal anatomy related to the erector spinae plane block and to report the spread of the dye...

Determining the extent of the dural sac for the performance of caudal epidural blocks in newborns.

Information regarding the position and relationship of vital structures within the caudal canal is important for anesthesiologists who perform a caudal block. This information can be acquired by anatomical dissection, with ultrasound technology, or radiological studies. The aim of this study was to determine the position of the dural sac in neonates by measuring the distance of the termination of the dural sac from the apex of the sacral hiatus in neonatal cadavers. After careful dissection, the distance from the apex of the sacral hiatus to the dural sac was measured in a sample of neonatal cadavers. In 39 neonatal cadavers, the mean distance from the apex of the sacral hiatus to the dural sac was 10.45 mm. The range of this distance was between 4.94 and 26.28 mm. The mean distance for females was 9.64 mm (range from 6.66 to 15.09); that for males was 10.90 mm (range between 4.94 and 26.28). Linear regression with the log of this distance as the outcome variable gave an estimated 3.3% increase in the distance for each 1 cm increase in the length of the neonate (95% CI for this proportion was 1.91-4.71). Anesthesiologists should be aware of the short distance between the sacral hiatus and the dural sac when performing caudal blocks, the shortest distance was 4.94 mm. Armed with this knowledge, caudal techniques should be modified to improve the safety and reduce the risk of complications, such as dural puncture.

Anatomical description of the sciatic nerve block at the subgluteal region in a neonatal cadaver population.

Sciatic nerve blocks provide intraoperative and prolonged postoperative pain management after lower limb surgery (posterior knee, foot, skin graft surgery). Accurate needle placement requires sound anatomical knowledge. Anatomical studies on children are uncommon; most have been performed on adult cadavers. We studied the location of the sciatic nerve at the gluteal level in neonatal cadavers to establish useful anatomical landmarks. We identified the sciatic nerve in the gluteal and thigh region of 20 neonatal cadavers. The skin covering the gluteal and thigh region was reflected laterally, and the underlying structures and muscles were identified. We located the sciatic nerve and measured the distance from the nerve to the greater trochanter of the femur and to the tip of the coccyx with a mechanical dial caliper. The total distance between the two landmarks was then recorded. We combined measurements from both sides to form a sample size n = 40. The sciatic nerve was 14.9 ± 2.4 mm lateral to the tip of the coccyx. The total distance between the greater trochanter and the tip of the coccyx was 27.3 ± 4.0 mm. Our results provide anatomical evidence that the optimal needle insertion point is approximately halfway between the greater trochanter and the tip of the coccyx-a landmark readily palpable in neonates and infants.

A theoretical alternative intraosseous infusion site in severely hypovolemic children.

BackgroundStudies have shown that the venous system tends to collapse during hypovolemic shock. The use of the bone marrow space for infusions is an effective alternative, with the tibial insertion site being the norm.ObjectivesThis study was conducted to determine a quick intraosseous infusion method that could be an alternative to the tibial route in neonates during emergency situations.MethodA sample of 30 neonatal cadavers was dissected to explore a possible alternative to the tibial insertion site. The needle was inserted in the superolateral aspect of the humerus. The needle infusion site was then dissected to determine possible muscular and neurovascular damage that might occur during the administration of this procedure, with the greatest concern being the posterior circumflex humeral artery and axillary nerve exiting the quadrangular space. The distance of the needle insertion site was measured in relation to the soft tissue as well as to bony landmarks.ResultsThe calculated 95% confidence interval shows that the needle can be safely inserted into the intraosseous tissue at the greater tubercle of the humerus 9.5 mm – 11.1 mm from the acromion. This is about a little finger’s width from the acromioclavicular joint.ConclusionAnatomically, the described site is suggested to offer a safe alternative access point for emergency infusion in severely hypovolemic newborns and infants, without the risk of damage to any anatomical structures.

In-house development of a neonatal chest simulation phantom.

The aim of the study was to design and construct an anatomical and radiological phantom of a neonatal chest for investigating image quality and patient entrance surface dose (ESD). The density, elemental composition, scatter, attenuation, and absorption characteristics of different possible substitute materials were compared to that of neonatal tissues for radiological equivalence. Availability and cost of possible substitute materials were also considered. The most optimal substitute materials were selected to represent neonatal muscle, bone, healthy or aerated and sick or collapsed lung. For anatomical equivalence, a computed tomography (CT) scan was performed on a neonatal cadaver. Dimensions of different organs and structures were measured with software measuring tools at different window and level settings. Simplifying assumptions, due to machining limitations, were made. The results were used to create scaled drawings, which were used to machine the structures of the phantom. The phantom was assembled in a layer‐by‐layer manner and was validated with region of interest (ROI) analyses. The neonatal chest simulation phantom was an acceptable simulation of a real neonatal chest based on ROI validation, with an overall deviation of 32.5%. The phantom was successfully used in our diagnostic radiology division for ESD and image quality investigations for chest anterior‐posterior (AP) radiographs.PACS numbers: 87.57.C‐; 87.59.B‐; 41.50.+h

The value of Tuffier's line for neonatal neuraxial procedures

The spine of L4 usually lies on a line drawn between the highest points of the iliac crests (Tuffier's line) in adults. Although its accuracy has been questioned, it is still commonly used to identify the spinous process of the 4th lumbar vertebra before performing lumbar neuraxial procedures. In children, this line is said to cross the midline at the level of L5. A literature search revealed that the description this surface anatomical line is vague in neonates. The aims of this study were to determine the vertebral level of Tuffier's line, as well as its distance from the apex of the sacrococcygeal membrane (ASM), in 39 neonatal cadavers in both a prone and flexed position. It was found that when flexed, Tuffier's line shifted from the level of L4/L5 (prone position) to the upper third of L5. The mean distance from the ASM to Tuffier's line was 23.64mm when prone and 25.47 mm when flexed, constituting a statistically significant increase in the distance (P=0.0061). Therefore, in the absence of advanced imaging modalities, Tuffier's line provides practitioners with a simple method of determining a level caudal to the termination of the spinal cord, at approximately the L4/L5 in a prone neonate and the upper margins of L5 when flexed.

Revisiting the anatomy of the ilio‐inguinal/iliohypogastric nerve block

The ilio-inguinal/iliohypogastric nerve block (INB) is one of the most common peripheral nerve block techniques in pediatric anesthesia, which is largely due to the introduction of ultrasound (US) guidance. Despite the benefits of US guidance, the absence of an US machine should not deter the provider from performing INB, considering that many institutions, especially in developing countries, cannot afford to provide ultrasound machines in their anesthesiology departments. The aim of this study was to revisit the anatomical position of the ilio-inguinal and iliohypogastric nerves in relation to the anterior superior iliac spine (ASIS), in a large sample of neonatal cadavers, and compare the results with a similar group in a previously published US-guided study. With Ethics Committee approval, the ilio-inguinal and iliohypogastric nerves were carefully dissected in 54 neonatal cadavers. In the total sample, the ilio-inguinal nerve was found to be 2.2±1.2mm from the ASIS, on a line connecting the ASIS to the umbilicus. The iliohypogastric nerve was on average 3.8±1.3mm from the ASIS. For the entire sample, the optimal needle insertion site was 3.00mm from the ASIS. Although there is a strong correlation between the needle insertion point and the weight of the neonate, this will only 'fit' for 60% of the population. The linear regression formula; needle insertion distance (mm)=0.6×weight+1.8 can be used as a guideline for the position of the ilio-inguinal and iliohypogastric nerves.

Enhanced generation of retinal progenitor cells from human retinal pigment epithelial cells induced by amniotic fluid

BackgroundRetinal progenitor cells are a convenient source of cell replacement therapy in retinal degenerative disorders. The purpose of this study was to evaluate the expression patterns of the homeobox genes PAX6 and CHX10 (retinal progenitor markers) during treatment of human retinal pigment epithelium (RPE) cells with amniotic fluid (AF), RPE cells harvested from neonatal cadaver globes were cultured in a mixture of DMEM and Ham's F12 supplemented with 10% FBS. At different passages, cells were trypsinized and co-cultured with 30% AF obtained from normal fetuses of 1416 weeks gestational age.ResultsCompared to FBS-treated controls, AF-treated cultures exhibited special morphological changes in culture, including appearance of spheroid colonies, improved initial cell adhesion and ordered cell alignment. Cell proliferation assays indicated a remarkable increase in the proliferation rate of RPE cells cultivated in 30% AF-supplemented medium, compared with those grown in the absence of AF. Immunocytochemical analyses exhibited nuclear localization of retinal progenitor markers at a ratio of 33% and 27% for CHX10 and PAX6, respectively. This indicated a 3-fold increase in retinal progenitor markers in AF-treated cultures compared to FBS-treated controls. Real-time PCR data of retinal progenitor genes (PAX6, CHX10 and VSX-1) confirmed these results and demonstrated AF's capacity for promoting retinal progenitor cell generation.ConclusionTaken together, the results suggest that AF significantly promotes the rate of retinal progenitor cell generation, indicating that AF can be used as an enriched supplement for serum-free media used for the in vitro propagation of human progenitor cells.

Morphologic Investigation of Ventriculus Terminalis in Newborns: Embryologic and Clinical Implications

Objectives The aim of this study is to determine morphometric measurements and the variations of the microscopic appearance of the ventriculus terminalis (VT) in the conus medullaris of spinal cord in the newborns. Methods Material included 35 conus medullaris of the spinal cords obtained from the neonatal cadavers at Ondokuz Mayis University, Medical Faculty Samsun, Turkey, between 2005 and 2009. After a standard dissection, a microscopic study was conducted with a light microscope and a charge coupled device camera and a Mac Vision composite video system. Results The microscopic anatomic results showed that the VT has 5 main types: spherical-ovoid, elliptical, dilated, forking, and outpouching. In 3 specimens (8.6%), VT had dilated type; in 2 specimens (5.7%), forking type; in 16 specimens (45.7%), elliptical type; in 11 specimens (31.4%), spherical-ovoid type; in 3 specimens (8.6%), outpouching type. Anteroposterior and transverse diameters of the VT range from 2 to 15 mm and 7 to 31 mm, respectively. Conclusion The VT (fifth ventricle) is a normal anatomic structure and is infrequently reported as responsible for neurologic findings, especially in adults. It has different morphologic patterns in the neonatal period without common characteristic. The information reported in this study is of clinical and embryologic value in the practice and diagnosis of pathologies of conus medullaris of spinal cord.

The termination of superior sagittal sinus and drainage patterns of the lateral, occipital at confluens sinuum in newborns: clinical and embryological implications

Drainage patterns of dural venous sinuses at confluens sinuum are variable and clinically significant. It has been generally investigated in adults; however, we thought that neonatal cadaver study might be more informative in views of embryological and clinical. A total of 33 skull bases of neonatal cadavers were resected to identify termination patterns of lateral sinus (LS), superior sagittal sinus (SSS) and occipital sinus (OS) at the confluens sinuum. Termination patterns of these sinuses were classified into six types: the SSS showed continuity with right transverse sinus (TS) (with OSs) (30.3%) (Type I); or multiple OSs (21.2%) (Type II). The SSS continued with left TS (with OSs) (12.1% (Type III); or with multiple OSs (6.1%) (Type IV). The SSS shows continuity with both TS (9.1%) (Type V). SSS symmetrically bifurcated, the confluens sinuum has a large OS (21.2%) (Type VI). Understanding of the cerebral venous drainage and large variation of the posterior fossa dural sinuses is crucially important for planning surgical intervention to some tumors in the neck which may require ligation of the internal jugular vein.

Localization of pterion in neonatal cadavers: a morphometric study

Pterion is defined as a junction of temporal, frontal, parietal, and sphenoid bones. In newborns, pterion may be defined as a region that shows variability in the exact location because of the lack of complete bony structure. The aim of this study is to define the topographic anatomy of this important surgical point, pterion, and the variability of its localization on craniums of newborn cadavers. Our study was performed using 35 term neonatal cadaver specimens. We measured the distances between the pterion and other critical points and used a scale diagram for the definition of pterional area. Our scale diagram showed that pterion is mostly localized in regions c, d, e, and f on the length and regions 2, 3, 4, and 5 on the width. Localization was not observed in regions a, b, g, and h, and in areas of squares 1 and 6. The most observed localization of pterion was the e4 (24.28%) area. This study provides a detailed knowledge on localization of this important point, pterion, which will be useful for the clinicians at operation planning and treatment stages, serving for the success in surgery in the presence of this variable topographic cranial anatomy.

Anatomic and arthroscopic study of the medial meniscal horns’ insertions

The insertions of the menisci to the tibia are the most important restraints to extrusion from the knee joint, and are vital for the functional integrity of the menisci. The aim of the present study was to determine variations of tibial insertions of the medial menisci (MM) in newborn cadavers macroscopically and in adults by arthroscopy. Neonatal part of this study was performed on 40 knee joints of 20 Caucasian neonatal cadavers. Adult part was performed on 41 Caucasian adults, whose ages were between 17 and 66 unilaterally by arthroscopy. In neonatal cadavers, according to its insertion, anterior horn of MM was classified in five groups and type 4, in which it was inserted to the transverse ligament, was determined the most frequent one (45%) and posterior horn of MM was classified in three groups and type 3, in which it was inserted to both the posterior intercondylar area of tibia and medial tubercle of intercondylar eminence was determined the most frequent one (50%). In adults, anterior end of MM was most frequently inserted to both anterior intercondylar area of tibia and transverse ligament (76%) and posterior horn of MM was inserted to the posterior intercondylar area of tibia in all of them. This study provides comparative information about insertion of the MM for neonatals and adults, not to evaluate the variants of the insertion of the MM as a tear of the anterior cruciate ligament or a meniscal tear and not to complicate arthroscopy.