Free thyroid transfer to anterolateral thigh for prevention of radiation induced hypothyroidism: An initial experience.

AIM: Radiation induced hypothyroidism (RIHT) is one of the commonest late side effects of radiation therapy and is seen in more than half of patients and affects quality of life significantly. We report our initial experience on feasibility of free microvascular transfer of thyroid gland out of radiation field to prevent development of RIHT. MATERIAL AND METHODS: A prospective pilot study was undertaken during August 2017 to May 2018. Six Patients with stage III/IV patients of oral cavity cancers who required wide excision/composite resections with microvascular free flap (ALT) reconstruction and adjuvant radiation therapy were enrolled. A written informed consent was obtained from all patients prior to the procedure. RESULTS: The mean age of cohort was 51 years with tongue most common site of primary cancer. The free transfer of thyroid gland to anterolateral thigh was done using microvascular technique. The mean additional time for procedure was 51 min. All patients had successful transfer with no associated immediate complications. Patients were followed up with Tc99 scan, USG Doppler and biochemical assay at routine intervals in peri and postoperative period to assess the anatomical and physiological function of the transferred gland. At median follow up of 8 months, 5 patients were euthyroid and remaining one had biochemical hypothyroidism. All patients had functional thyroid gland in anetrolateral thigh. Five patient were alive, one patient died due to disease. CONCLUSION: This is a small and early feasibility study for free thyroid gland transfer and validates the previously published data. The selected group of patients who have high chances of developing RIHT may benefit from this strategy. Further validation of the technique may be explored in a larger cohort.

[Transoral approach to thyroid gland in the experiment]. / Transoral'nyi dostup k shchitovidnoi zheleze v eksperimente (s kommentariem P.S. Vetsheva).

AIM: To develop minimally invasive and safe endoscopic access to thyroid gland. MATERIAL AND METHODS: Transoral pre-mandibular video-assisted gas-free access to thyroid gland was developed in experimental study that included 19 human cadavers. Stereometric modeling defined the evaluation criteria including the form of basal arch of lower jaw and its height. There was no conflict of instruments in working chamber under platysma. Additional trocar was deployed to resolve the conflict between working parts of instruments during thyroid gland mobilization. The angle of operative action between the instruments is close to 90°. Trocar hole is used for drainage. RESULTS: The access provides good visualization of recurrent laryngeal nerve, upper and lower thyroid arteries and parathyroid gland. It is less traumatic compared with other extra-cervical accesses to thyroid glands.

A Computational Template for Three-Dimensional Modeling of the Vascular Scaffold of the Human Thyroid Gland.

We recently designed an innovative scaffold-bioreactor unit for the bioengineering of a three-dimensional (3D) bioartificial human thyroid gland or its miniaturized replica as a part of a microfluidic chip test system. This device is based on the evidence that the 3D geometry of the intraglandular stromal/vascular scaffold (SVS; i.e., the fibrous and vascular matrix) of mammalian viscera plays a key role in guiding growth and differentiation of in vitro seeded cells. Therefore, we initiated a research program focused on computer-aided reconstruction of the 2nd to 4th order intralobar arterial network (IAN) of the human thyroid gland as a reliable surrogate for its 3D SVS, to be used as an input for rapid prototyping of a biomaterial replica. To this end, we developed a computational template that works within the Mathematica environment, giving rise to a quasi-fractal growth of the IAN distribution, constrained within an approximation of the thyroid lobe shape as a closed surface. Starting from edge detection of planar images of real human thyroid lobes acquired by in vivo real-time ultrasonography, we performed data approximation of the lobar profiles based on splines and Bezier curves, providing 3D lobar shapes as geometric boundaries for vessel growth by a diffusion-limited aggregation model. Our numerical procedures allowed for a robust connection between development of lobar arterial trees and thyroid lobe shape, led to a vascular self-similarity consistent with that of a cadaveric lobar arterial cast, and reproduced arterial vessels in a proportion not statistically different from that described for the real human thyroid gland. We conclude that our algorithmic template offers a reliable reproduction of the extremely complex IAN of the adult human thyroid lobe, potentially useful as a computational guidance for bioprinting of thyroid lobe matrix replicas. In addition, due to the simplicity and limited number of morphometrical parameters required by our system, we predict its application to the design of a number of patient-tailored human bioartificial organs and organs-on-chip, including parenchymal viscera and bones. Impact statement The study introduces the computer simulation of the three-dimensional (3D) intrinsic vascular matrix of the human thyroid gland, offering a general concept applicable to a number of other human viscera. Indeed, it provides a flexible software tool for reproduction of a 3D surrogate of the organ's 3D stromal matrix, suitable for eventual 3D bioprinting with biomaterials, and recellularization with organ-specific stem cells/progenitors. The final expectation is the design of patient-tailored 3D organ's matrices upon clinical request.

Variations in origin of the superior thyroid artery: an update for the head and neck surgeon.

Head and neck surgeons must have a thorough knowledge of head and neck vascular anatomy and its variations. This case report documents a variation in the superior thyroid artery encountered during a neck dissection and discusses the surrounding literature. A 55-year-old female with squamous cell carcinoma of the tongue underwent a partial glossectomy, right level I-IV neck dissection and reconstruction with a radial forearm free flap. During the procedure, an arterial branch was encountered arising 2-3cm caudal to the common carotid bifurcation. This variant branch was shown to represent the superior thyroid artery. On review of the literature, various classification systems of the superior thyroid artery origin have been described. Awareness of such anatomical variation is vital for the head and neck surgeon to avoid unexpected complication.

Contribution of Interventional Radiologist in the Management of Pseudoaneurysm and Neck Hemorrhages in COVID-19 patients.

Patients with severe coronavirus disease 2019 (COVID-19) may have endothelial inflammation, pseudoaneurysm, and an increasing risk of bleeding, especially during surgical procedures. In this article, we reported 2 cases of COVID-19 patients with neck vascular lesions. The first patient had pseudoaneurysm of the cricothyroid artery, which was treated by percutaneous glue injection through ultrasonography guidance. The second patient presented lateral neck hematoma in front of the left superior thyroid artery, which was managed by coil endovascular embolization. In the context of pandemic, the management of vascular lesions may be performed through interventional radiological procedures that may reduce the risk of virus aerosolization and health care provider contamination.

The bioartificial thyroid: a biotechnological perspective in endocrine organ engineering for transplantation replacement.

A new concept for ex situ endocrine organ bioengineering is presented, focused on the realization of a human bioartificial thyroid gland. It is based on the theoretical assumption and experimental evidence that symmetries in geometrical coordinates of the thyroid tissue remain invariant with respect to developmental, physiological or pathophysiological transformations occuring in the gland architecture. This topological arrangement is dependent upon physical connections established between cells, cell adhesion molecules and extracellular matrix, leading to the view that the thyroid parenchyma behaves like a deformable "putty", moulded onto an elastic stromal/vascular scaffold (SVS) dictating the final morphology of the gland. In particular, we have raised the idea that the geometry of the SVS per se provides pivotal epigenetic information to address the genetically-programmed, thyrocyte and endothelial/vascular proliferation and differentiation towards a functionally mature gland, making organ form a pre-requirementfor organ function. A number of experimental approaches are explored to obtain a reliable replica of a human thyroid SVS, and an informatic simulation is designed based on fractal growth of the thyroid intraparenchymal arterial tree. Various tissue-compatible and degradable synthetic or biomimetic polymers are discussed to act as a template of the thyroid SVS, onto which to co-seed autologous human thyrocyte (TPC) and endothelial/vascular (EVPC) progenitor cells. Harvest and expansion of both TPC and EVPC in primary culture are considered, with specific attention to the selection of normal thyrocytes growing at a satisfactory rate to colonize the synthetic matrix. In addition, both in vitro and in vivo techniques to authenticate TPC and EVPC lineage differentiation are reviewed, including immunocytochemistry, reverse trascriptase-polymerase chain reaction, flow cytomery and proteomics. Finally, analysis of viability of the thyroid construct following implantation in animal hosts is proposed, with the intent to obtain a bioartificial thyroid gland morphologically and functionally adequate for transplantation. We believe that the biotechnological scenario proposed herein may provide a template to construct other, more complex and clinically-relevant bioartificial endocrine organs ex situ, such as human pancreatic islets and the liver, and perhaps a new approach to brain bioengineering.

Bioprinting of a functional vascularized mouse thyroid gland construct.

Bioprinting can be defined as additive biofabrication of three-dimensional (3D) tissues and organ constructs using tissue spheroids, capable of self-assembly, as building blocks. The thyroid gland, a relatively simple endocrine organ, is suitable for testing the proposed bioprinting technology. Here we report the bioprinting of a functional vascularized mouse thyroid gland construct from embryonic tissue spheroids as a proof of concept. Based on the self-assembly principle, we generated thyroid tissue starting from thyroid spheroids (TS) and allantoic spheroids (AS) as a source of thyrocytes and endothelial cells (EC), respectively. Inspired by mathematical modeling of spheroid fusion, we used an original 3D bioprinter to print TS in close association with AS within a collagen hydrogel. During the culture, closely placed embryonic tissue spheroids fused into a single integral construct, EC from AS invaded and vascularized TS, and epithelial cells from the TS progressively formed follicles. In this experimental setting, we observed formation of a capillary network around follicular cells, as observed during in utero thyroid development when thyroid epithelium controls the recruitment, invasion and expansion of EC around follicles. To prove that EC from AS are responsible for vascularization of the thyroid gland construct, we depleted endogenous EC from TS before bioprinting. EC from AS completely revascularized depleted thyroid tissue. The cultured bioprinted construct was functional as it could normalize blood thyroxine levels and body temperature after grafting under the kidney capsule of hypothyroid mice. Bioprinting of functional vascularized mouse thyroid gland construct represents a further advance in bioprinting technology, exploring the self-assembling properties of tissue spheroids.

Thyroid hemangioma.

A case is presented of a fifty-six year old man with a thyroid hemangioma presenting as a neck mass with tracheal deviation and unilateral vocal cord paralysis. A standard thyroid scan yielded equivocal findings. The diagnosis was determined preoperatively by the use of a 99m-technetium angiogram that disclosed the vascular nature of the lesion. Subsequent arteriography demonstrated the main arterial supply of the mass to be from both inferior thyroid arteries. Operative removal of the mass was accomplished through a standard transverse cervical incision. Pathologic study revealed that the vascular tumor involved both the surrounding normal thyroid parenchyma and also a microfollicular adenoma. This case points out the value of utilizing all available diagnostic means in atypical cases of thyroid disease.

Experimental evaluation and clinical use in the head and neck of a 3M/Precise microvascular anastomotic device.

Microvascular reconstructions in the head and neck are usually long operating time procedures. Mechanical anastomotic devices help to reduce operating time and can reduce anastomotic failures avoiding foreign bodies in the lumen of the vessel. One of these systems is the 3M/Precise microvascular anastomotic device, it is a non-absorbable device, however, criticisms of this system have been directed to the fact that pulsation of the vessel wall against a rigid structure could lead to thinning of the vessel wall and aneurysm formation. No aneurysms have been found previously in other experimental models. Our experimental study on the aorta and vena cava of the rat comprises 25 arterial and 25 venous anastomoses. In the arteries, four proximal aneurysms were found, two of these were failures. In the venous anastomoses, no failures were found nor aneurysm formation. The system is very useful for performing clinical end to end venous anastomosis helping to reduce anastomotic failures. Aneurysms have been found in arteries although four different ring sizes were available. The device is less easy to use in them than in veins and sometimes can be difficult to apply, making manual suturing a better choice for clinical arterial anastomosis.

Comparison of two types of arterialized venous forearm flaps for oral reconstruction and proposal of a reliable procedure.

The mechanism of survival of venous flaps is not yet completely understood. To determine the conditions for reliable success, in 1996 and 1997 we used arterialized venous forearm flaps for oral reconstruction in patients with neoplastic disease. Building on earlier experience with flow-through flaps, we compared two different designs obeying the following specifications: five so-called arterialized flow-through flaps, elevated from the ulnar flexor side of the forearm, with a single vein for orthograde inflow and outflow, diameter not larger than 2 mm (type 1); and five arterialized flaps with two parallel veins on the proximal side of the flap, also with a diameter of 1-2 mm, to avoid by-passing of flap tissue by 'catching' the blood in the venous/capillary system (type 2). There were nine male and one female patients with a mean age of 55.7 years. We covered defects of the anterior or anterolateral floor of the mouth to avoid folding of the flaps. Microsurgical anastomosis was done to the facial artery, the cranial thyroid artery and the external jugular vein or the facial vein. Average size of the flaps was 23 +/- 7.28 cm2 (type 1) and 25 +/- 5 cm2 (type 2). Four flaps of type 1 showed total or subtotal success and only one was lost because of a haematoma. In comparison with this we saw three losses in type 2 and only one partial and one total success, respectively. Analysis showed regularly occurring problems: there was failure of venous drainage in the lost type 2 flaps one day after microsurgery. In the flow-through flaps and the surviving type 2 flaps which had visible communicating branches between the two veins, the partial by-passing of the arterial input avoided this problem. There was no donor site morbidity after covering with a split-thickness skin graft. It could be shown that survival of arterialized venous forearm flaps is based on a combination of an arteriovenous shunt and capillary blood flow. In conclusion, we define six rules for a reliable venous forearm flap.

"Chain-link" combined tissue transfer for the reconstruction of the mandible.

We describe a procedure for "chain-link" combined tissue transfer connecting the vascular pedicle of a deep circumflex iliac flap with that of a forearm flap after wide resection of the mandible. Combination of these flaps facilitated the reconstruction of the defect in both intra- and extraoral soft tissue and the mandibular bone. This method is useful when cervical recipient blood vessels are limited due to the wide resection of the primary tumor and radical neck dissection.

Infrahyoid myocutaneous flap in reconstructive maxillofacial cancer and trauma surgery.

We report the use of an island infrahyoid myocutaneous flap, pedicled on the superior thyroid vessels, in a group of 21 patients. This flap allows reconstruction of intraoral defects or defects of the lower portion of the face, as large as 10 x 4 cm. We used it in 15 cases to repair parts of the oral cavity, after tumour resection, in 2 patients with mandibular osteoradionecrosis and in 4 patients with gunshot injuries. Among the 21 flaps, no muscular necrosis was observed; however, 4 total necrosis and 4 partial necrosis (< or = 25% of the skin area) of the skin paddle were recorded. Loss of the skin paddle was primarily attributable to the anatomical variations of the veins draining this flap.

[Neurovascular infrahyoidal myofascial flap. Anatomic and topographic study of the innervation and blood supply]. / Der neurovaskuläre infrahyoidale Muskelfaszienlappen. Anatomisch topographische Untersuchung der Innervation und Gefässversorgung.

The neurovascular infrahyoidal myofascial flap: An anatomical and topographical study of the innervation and blood supply. 15 cadavers had bilaterally been examined for the topography of the upper thyroid artery and vein and of the lower cervical ansa, as an axial bundle of vessels and nerves for the infrahyoidal myofascial flap. With the injection of methylene blue the vascular territories of the upper thyroid artery had been demonstrated. The upper thyroid artery and vein could be found in all cases. This artery was deriving in 47% from the external carotid artery, in 30% from the bifurcation and in 23% from the common carotid artery. The vein flowed in 43% into the facial vein and in 37% into the internal jugular vein. In the remaining 20% several segmental veins were found, which flowed into the jugular vein separately. In case of a far caudally situated vascular bundle the radius of rotation can be limited in cranial direction. The voluntary innervation of the muscles of this flap is derived from the lower cervical ansa. The upper radix of the ansa can be found 1 cm in latero-cranial direction of the greater horn of the hyoid bone, where it is separating from the hypoglossal nerve. The upper thyroid artery is supplying the infrahyoidal musculature in the whole extension from the hyoid bone to the sternum. Therefore it is possible to develop a myofascial flap of 3.5 cm x 11.5 cm in size, which is pedicled at an upper vascular and nerval bundle. Depending on the radius of rotation defects of the floor of mouth, of the tongue and of the oro- and hypopharynx can well be covered with this new neurovascular myofascial flap.

Survival of a free flap after vascular disconnection at 9 days.

It is not known how long it takes for a radial forearm free flap to develop its own independent blood supply from its recipient bed. This article describes a case in which vascular disconnection of the pedicle happened at 9 days postoperatively and yet the graft survived via its own independent blood supply.

Use of the radial forearm artery for secondary embolization of an extensive life-threatening arteriovenous malformation of the mid-face and anterior skull base - a case report.

BACKGROUND: Arteriovenous malformations (AVM) of the head and neck are rare conditions with the majority of primary sites in the mid-face. Progression can lead to massive life-threatening bleeding. Treatment of choice is the combination of embolization and surgical resection. Diagnosis and management of AVM has been facilitated in recent years by the progress in imaging techniques and various microsurgical and endovascular embolization procedures. METHODS: This report presents the interdisciplinary approach to a case of life-threatening AVM of the mid-face in a 30-year-old patient. RESULTS: Angiography with embolization followed by resection and plastic reconstruction was performed. Follow-up showed incomplete obliteration of the AVM and lead to additional embolizations via the anastomosed radial artery. Complete eradication of the AVM was not possible during the three year follow-up period. CONCLUSION: In extensive vascular malformations of the head and neck, complete surgical removal is often impossible and associated with high risk of complications and mortality. Endovascular embolization is limited by the location of the AVM and can potentially cause stroke, ischaemia, necrosis, bleeding, blindness and adverse haemodynamic changes.

The sternocleidomastoid perforator flap.

The conventional pedicled sternocleidomastoid (SCM) flap has a poor arc of rotation, limited volume and precarious vascularity. This report describes a new technique for raising a SCM flap based on the perforating vessels of the superior thyroid vascular pedicle. The upper and lower attachments of the sternocleidomastoid muscle are divided. Four medically and/or surgically compromised patients have successfully undergone reconstruction of hemiglossectomy (1), partial glossectomy (1) and rim of mandible (2) defects for malignancy. The arc of rotation of the SCM flap is greatly increased and the potential applications for the flap expanded.

A study on the relationship between intraglandular arterial distribution and thyroid lobe shape: implications for biotechnology of a bioartificial thyroid.

We have recently hypothesized that structural and secretory components of the adult human thyroid gland maintain constant reciprocal and geometrical relationships, even if changes occur in the three-dimensional (3D) architecture of any of these elements. This means that thyroid morphology could be studied from the point of view of a 3D topology. As a consequence, we have investigated anatomical aspects that could support this assumption. In the present study, we show that the presence of a constant relationship can be demonstrated between the vascular arrangement of the gland, including the extension of intraglandular arterial fields, arterial anastomoses and arterial calibers, and the shape as well as volume of the thyroid. Specifically, a statistically significant difference has been found between the network amplitudes of the superior and inferior thyroid arteries in relation to either a conic or an ellipsoidal geometry of the thyroid lobe. In addition, a direct relationship has been implicated between the distribution of arterial anastomoses and the behavior of the lobe as a single hemodynamic unit. Finally, a statistically significant correlation has been observed between average arterial caliber of the inferior thyroid artery and thyroid volume. On the basis of these results, we propose a model of architectural assembly between stromal and parenchymal elements of the adult thyroid that might prove useful in designing a bioartificial gland ex situ. Potential clinical applications of this principle in regenerative medicine of other endocrine organs are highlighted.

[Formalin-free method of preserving endocrine glands of the branchiogenous group (thyroid, parathyroid and thymus)]. / Besformalinovyi metod konservirovaniia zhelez vnutrennei sekretsii brankhiogennoi gruppy (shchitovidnoi, okoloshchitovidnoi i vilochkovoi

The authors propose a conservation method developed at the Department of Normal Anatomy of the Pavlov First Medical Institute. The conservation is performed by simultaneous using of chemicals upon which the method is based: conservant and latex. The conservant is a mixture of glycerine, potassium acetate and water in proportion 45% : 10% : 45%. The latex is industrial artifical rubber.