FEASIBILITY STUDY OF MAGNETIC RESONANCE IMAGINING APPLICATION IN EXPERIMENTAL RADIOLOGY FOR INTRAVITAL VERIFICATION OF LUNGS METASTASES IN MICE

Background. For preclinical studies of radiopharmaceuticals there is a high need for development new methods of in vivo metastasis diagnosis in mice after tumor cells transplantation. The study was carried out to assess feasibility of lung metastasis diagnosis with magnetic resonance imaging (MRI) visualization in mice C57Bl6.The aim of this study was to assess feasibility of MRI for verification of distant metastases of the solid B16-F10 melanoma with validation by anatomic dissection.Methods. Metastatic lesions were caused by injection of B16-F10 murine melanoma cells into cavum medullare of the tibia. Imaging studies were performed on the 21th day after transplantation using 7T magnetic resonance tomograph, coronal and axial images were acquired. Validation of metastasis was made by anatomic dissection and histological examination.Results. MRI method enables visualization of lung nodules with diameter at least 0.8 mm, because smaller nodules cannot be distinguished from heartbeat artifacts. Histological examination revealed that macroscopic anatomic dissection can precisely detect subpleural lung nodules.Conclusion. This study demonstrated feasibility of in vivo lung metastasis verification with MRI method in mice: metastases comparable in diameter to the size of large bronchi can be detected by MRI as well as by ex vivo dissection. For centrally located lung metastasis MRI method is preferable because macroscopic dissection enables to visualize only nodules which are located subpleurally.

Modular Approach to Open Partial Horizontal Laryngectomy: Step-by-Step Anatomic Dissection

Open partial laryngectomies still play an important role in contemporary conservative management of laryngeal cancer. A comprehensive and systematic classification of open partial horizontal laryngectomies (OPHLs) was presented by the European Laryngological Society working committee in 2014. The aim of this video is to show the main surgical steps in OPHL using a cadaveric dissection and to explain the modular approach for removal of laryngeal tumors.

The morphology, biomechanics, and physiological function of the suboccipital myodural connections

The myodural bridge (MDB) connects the suboccipital musculature to the spinal dura mater (SDM) as it passed through the posterior atlanto-occipital and the atlanto-axial interspaces. Although the actual function of the MDB is not understood at this time, it has recently been proposed that head movement may assist in powering the movement of cerebrospinal fluid (CSF) via muscular tension transmitted to the SDM via the MDB. But there is little information about it. The present study utilized dogs as the experimental model to explore the MDB’s effects on the CSF pressure (CSFP) during stimulated contractions of the suboccipital muscles as well as during manipulated movements of the atlanto-occiptal and atlanto-axial joints. The morphology of MDB was investigated by gross anatomic dissection and by histological observation utilizing both light microscopy and scanning electron microscopy. Additionally biomechanical tensile strength tests were conducted. Functionally, the CSFP was analyzed during passive head movements and electrical stimulation of the suboccipital muscles, respectively. The MDB was observed passing through both the dorsal atlanto-occipital and the atlanto-axial interspaces of the canine and consisted of collagenous fibers. The tensile strength of the collagenous fibers passing through the dorsal atlanto-occipital and atlanto-axial interspaces were 0.16 ± 0.04 MPa and 0.82 ± 0.57 MPa, respectively. Passive head movement, including lateral flexion, rotation, as well as flexion–extension, all significantly increased CSFP. Furthermore, the CSFP was significantly raised from 12.41 ± 4.58 to 13.45 ± 5.16 mmHg when the obliques capitis inferior (OCI) muscles of the examined specimens were electrically stimulated. This stimulatory effect was completely eliminated by severing the myodural bridge attachments to the OCI muscle. Head movements appeared to be an important factor affecting CSF pressure, with the MDB of the suboccipital muscles playing a key role this process. The present study provides direct evidence to support the hypothesis that the MDB may be a previously unappreciated significant power source (pump) for CSF circulation.

Sphenoidal artery: review of the literature and analysis of a dissected arterially injected fetal orbit

Purpose The sphenoidal artery is considered a component of the complex and dangerous arterial anastomoses of the human orbitocranial region, particularly with the advent of interventional neuroimaging. The objective of this publication was to analyze the various descriptions of the sphenoidal artery in the literature as related to relevant photographs of a dissected arterially injected fetal middle cranial fossa and orbit. Methods Publications dealing with middle meningeal-ophthalmic arterial anastomoses, focusing on the sphenoidal artery, were reviewed. A relevant dissection of a fetal specimen was analyzed. Results The literature dealing with the sphenoidal artery is at times not in agreement. The nomenclature and anatomy of its passage through the superior orbital fissure or Hyrtl canal have variable descriptions. Photographs of the skull base of a dissected arterially injected fetal specimen show bilateral prominent orbital branches of the middle meningeal arteries. These branches entered both orbits in a course similar to the diagrammatic representations of the sphenoidal artery, and give rise to several major intraorbital arteries. This study provides the only photographic image in the literature of this variation in a human fetal anatomic dissection. Conclusions Review of the literature dealing with the sphenoidal artery shows inconsistent nomenclature and conflicting descriptions of its anastomotic connections, and varying evolutionary and embryologic theories. Analysis of the dissected fetal skull base indicates that the sphenoidal artery is not a distinct artery but just a middle meningeal orbital arterial branch, an important component of the complex and dangerous arterial anastomoses of the human orbitocranial region.

Avascular necrosis of the lunate secondary to perilunate fracture dislocation: Case report and review of the literature

This is a 39-year-old male, fell from a bike, left wrist with trans-styloid perilunate fracture dislocation that underwent open reduction internal fixation, 20 months after surgery the patient developed avascular necrosis of the lunate, final wrist fusion was performed secondary to the arthritic changes on the wrist. Anatomic dissection was performed and vascularity of the lunate was identified, its origin is from the volar palmar arch, when dislocated palmarly and more than 90 degrees the vessel is still intact. More than 512 patients with perilunate dislocation and perilunate fracture dislocation are included we identified in the literature transient avascular necrosis of the lunate in nine and seventeen of pure avascular necrosis of the lunate. Concluding that avascular necrosis of the lunate after perilunate dislocation or perilunate fracture dislocation is an infrequent finding especially when the volar ligaments are intact.

Optimizing the Mastectomy Flap to Improve Aesthetic Outcomes

The aesthetics of breast reconstruction inherently rely on both the ablative and reconstructive procedures. Mastectomy flap quality remains one of the most critical factors in determining the success of a reconstruction and its aesthetic outcome. Maintaining the segmental perfusion to the nipple and skin envelope during mastectomy requires preserving the subcutaneous tissue superficial to the breast capsule. Because this layer of tissue varies in thickness among different patients and within each breast, anatomic dissection along the appropriate planes is required rather than a “one-size-fits-all” mentality. A team-based approach between the breast surgeon and plastic surgeon will optimize both the ablative and reconstructive procedures while engaging in a process of shared decision-making with the patient. Preoperative clinical analysis and utilization of imaging to assess individual breast anatomy will help guide mastectomies as well as decisions on reconstructive modalities. Critical assessment of mastectomy flaps is paramount and requires flexibility to adapt reconstructive paradigms intraoperatively to minimize the risk of complications and provide the best aesthetic result.

Radiographic Methods Are as Accurate as Magnetic Resonance Imaging for Graft Sizing Before Lateral Meniscal Transplantation

Background: Accurate allograft matching is deemed critical for meniscal transplantation; thus, precise measurements are essential to correctly calculate meniscal size. Several methods for meniscal sizing have been described, but there remains a discussion on which is the most accurate for the lateral meniscus. Purpose: To compare the accuracy of radiographic, anthropometric, and magnetic resonance imaging (MRI) methods of determining width and length of the lateral meniscus with actual dimensions after anatomic dissection. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen human cadaveric knees without any evidence of meniscal or ligamentous injury were primarily imaged using radiography and MRI and subsequently underwent dissection to assess the anatomic size of each meniscus. Four methods were used to predict the size of the lateral menisci: anthropometric, radiographic (Pollard and Yoon), and MRI. Absolute differences in length and width between actual and predicted sizes were determined. Results: The anatomic lateral meniscal width and length were 33.01 ± 4.25 mm (mean ± SD; range, 24.84-40.18 mm) and 31.41 ± 5.06 mm (range, 25.2-40.05 mm), respectively. Regarding width, the anthropometric method demonstrated an absolute difference from anatomic measurement significantly greater when compared with the Pollard technique and MRI ( P = .002). Regarding length, the Pollard method presented an absolute difference significantly greater than all other techniques ( P = .003). In terms of the ability to measure width and length, MRI accurately predicted meniscal size within 10% of the anatomic size in 65% of measurements, the Yoon method in 54%, and the Pollard method in 20% ( P = .01). Radiographs tended to overestimate the true size of the lateral meniscus, while the anthropometric technique overestimated width in all specimens. Conclusion: This study demonstrated that MRI and the Yoon radiographic method are comparable in terms of accuracy for graft sizing before lateral meniscal transplantation. While MRI is useful, a contralateral MRI is required, which makes the Yoon radiographic method recommended given the ease and cost advantage. The original Pollard technique and the anthropometric method are not recommended. Clinical Relevance: Over- and undersizing of meniscal transplants has been implicated in graft failure. Therefore, increasing the reliability of preoperative meniscal measurements is deemed important for the success of meniscal allograft transplantation.

Deep gluteal space anatomy and its relationship with deep gluteal pain syndromes

Introduction: Increasing interest has been seen in understanding the anatomy and biomechanics involved in the Deep Gluteal Syndrome, therefore the main objective of our paper was to define the anatomy of the deep gluteal space concerning the important osseous, muscular and neurological structures. Methods: 12 cadaveric models (24 hemipelvises) were used. We proceeded with classical anatomic dissection and evaluated numerous osseous, musculotendinous and neurologic structures and their relationships. We also determined the femoral anteversion and neck-shaft angles. Results: We found that 15.4% of lower limbs examined presented variations in the sciatic nerve (SN) emergence, and this was significantly longer in men. The distance from the SN to the trochanteric region was also significantly lower in males. The average ischiofemoral distance (IFD) was 2.5 ± 1.3 cm, at the same time that the structures comprised in that space showed superior areas, such as the quadratus femoris (QF) with 5.0 ± 1.1 cm and the SN with 1.4 ± 0.3 cm widths. Besides that, we also evaluated the distance from the SN to the lesser trochanter (LT) and the ischial tuberosity (IT), in the ischiofemoral space, reaching average values of 1.1 ± 0.7 cm and 1.5 ± 0.6 cm respectively. Regarding the relationship between the proximal hamstring insertion, we verified that the LT was at an average distance of 1.6 ± 1.1 cm, that the SN was only 0.2 ± 0.3 cm lateral to it, and the PN is just 2.6 ± 1.2 cm proximal to it. Conclusions: Our study confirmed the extreme variation in the SN origin that can contribute to the Piriformis syndrome. The IFD obtained in our study showed that this distance was small for the structures contained in this space. The proximal hamstring insertion showed a significantly more extended footprint in males, which puts the pudendal nerve (PN) at higher risk of iatrogenic injury.