Vasa nervorum of epicardial nerves and valves of small veins investigated in porcine heart by two types of vascular injections.

The morphology of the vascular supply of peripheral branches of cardiac nerves has not been systematically described until now. The aim of this study was to describe the architectonics of the vasa nervorum of epicardial nerves in porcine hearts by using two injection techniques. Twenty-three hearts from young healthy pigs were used. In 10 hearts India ink solution was injected into the origin of the anterior interventricular branch. In another 10 hearts India ink solution was injected retrogradely through the coronary sinus. The hearts were then analyzed using a magnifying glass and light microscopy. The arterial injection showed the entirety of the rich venous components of the vasa nervorum, which often consisted of paired veins accompanying the epicardial nerves. The thickness of the nerves ranged from 50 to 815 µm. The vasa nervorum drained into larger subepicardial veins. In seven of the hearts prepared with venous injections the vasa nervorum of epicardial nerves were visualized in the same detail as in the arterial preparations and India ink solution filled the right ventricle via the smallest cardiac veins. The histological analysis of these seven hearts showed complete dehiscence and functional insufficiency of small and larger veins valves. In the other three hearts prepared with venous injections the valves were competent, which prevented retrograde filling of larger and smaller veins. The results obtained expand the current knowledge on epicardial nerves vasa nervorum and provide anatomical evidence behind the mechanism of retrograde application of cardioplegic solutions in cardiac surgery.

Peripheral nerve response to injury.

Oral and maxillofacial surgeons caring for patients who have sustained a nerve injury to a branch of the peripheral trigeminal nerve must possess a basic understanding of the response of the peripheral nerves to trauma. The series of events that subsequently take place are largely dependent on the injury type and severity. Regeneration of the peripheral nerve is possible in many instances and future manipulation of the regenerative microenvironment will lead to advances in the management of these difficult injuries.

Morphological study of the vasa nervorum in the peripheral branch of human facial nerve.

Given the length of axons reaching to distal regions, all peripheral nerves must derive nutrient supply not only for the nerve cell body, but also for the peripheral parts. Along the course of a peripheral nerve, in general, nutrient vessels accompany nerve fibers to peripheral regions in the form of "vasa nervorum" derived from the epineurium, reaching the endoneurium through the perineurium and forming a capillary plexus. In addition, in reconstructive procedures in plastic surgery, anastomosis of not only nerves, but also the vasa nervorum, has been reported to achieve improved outcomes. The present study therefore observed morphological features of the blood supply to the distal portion of the facial nerve in 14 sides of 14 adult cadavers (age at death, 46-86 years) under stereo microscopy after dye injection. The region of the epineurium was also observed under scanning electron microscopy (SEM). The vasa nervorum was seen to derive from a complex reticulation structure formed mainly by the superficial temporal, facial, transverse facial and zygomatico-orbital arteries with collateral supply from the supraorbital, deep temporal, buccal arteries and parotid branches. SEM showed that one capillary accompanied each perineurium in each nerve fascicle.

[Clinical research about the distribution of perineural vascular plexus of the facial nerve].

OBJECTIVE: To objectively evaluate the usefulness and the reliability of the perineural vascular plexus as a landmark for facial nerve as well as whether it will be a landmark for identification of the facial nerve in surgery for otology and neurotology by means of investigating the location of the facial nerve for prevention of iatrogenic facial palsy. METHODS: Prospective case series were designed. Three hundred and eleven consecutive patients were studied which required tympanoplasty for chronic otitis media or microsurgery for facial nerve decompression and congenitally malformation of the ear from July 2002 to July 2005. All the patients were operated by the first author. Perineural vascular plexus as a landmark for identification of the facial nerve in surgery were observed to assess the utility. RESULTS: The well recognized perineural vascular plexus were seen on the horizontal mesotympanic segment of the nerve in 95.8% of patients (298 cases), and only in 4.2% of the patients (13 cases), the vessel plexus was difficult to identify. The 95% confidence interval was from 93.6% to 98.0%. CONCLUSIONS: The vascular plexuses around or over the horizontal portion of the facial nerve provide an early and direct indicator of the location of the facial nerve. The perineural vascular plexus could be a dependable and reliable landmark for the identification the horizontal part of the facial nerve in surgery for otology and neurotology.

Anatomical study of the cutaneous perforator arteries and vascularisation of the biceps femoris muscle.

UNLABELLED: We present an anatomical study that describes the distribution of the cutaneous perforators (CP) of both heads of the biceps femoris muscle. MATERIAL AND METHODS: In this study, we dissected 18 legs from nine cadavers. The study was centered on the biceps femoris muscle and musculocutaneous perforator arteries from both muscular heads. Only perforator arteries with comitant vein diameters of over 0.5 mm were selected. The vascular origin and length were also studied. In all cases, measurements were taken from the bicondyle line. RESULTS: The measurements taken from the muscle bellies of the biceps gave the following results; for the long head 33.91 cm as medium length (SD = 2.70) and for the short head 23.85 cm as medium length (SD = 2.96). The total number of perforator arteries obtained from the two muscle bellies was 139, with the greatest percentage located in the lower half of the thigh. The majority follow an intramuscular route (80.48%) and less frequently they are septals (19.52%). The lengths of perforator arteries from its origin in the axial vessel of the muscle to the subcutaneous fat were, for the short head 5.01+/-1.33 (3.0-10.0), whereas the same measurement, in the long head was 4.54+/-1.36 (2.5-9.0). The principal vascular origin of the perforator arteries was the popliteal artery in both muscle bellies, whilst the second arterial vessel in importance was the first and second profunda perforator artery. CONCLUSION: From the results obtained in our work, we can deduce that it is always possible to locate perforator arteries in both muscle bellies; most frequently they have intramuscular distribution and are located in the proximity of the vascular septum. Their most common origins are the popliteal artery and first and second profunda perforator artery. Finally, it is possible to design pedicle and free flaps, with less morbidity and more versatility than musculocutaneous flaps.

Nerve and ganglion blood flow in diabetes: an appraisal.

Vasa nervorum, the vascular supply to peripheral nerve trunks, and their associated cell bodies in ganglia have unique anatomical and physiological characteristics. Several different experimental approaches toward understanding the changes in vase nervorum following injury and disease have been used. Quantative techniques most widely employed have been microelectrode hydrogen clearance palarography and [14C]iodoantipyrine autoradiographic distribution, whereas estimates of red blood cell flux using a fiber-optic laser Doppler probe offer real time data at different sites along the nerve trunk. There are important caveats about the use of these techniques, their advantages, and their limitations. Reports of nerve blood flow require careful documentation of physiological variables, including mean arterial pressure and nerve temperature during the recordings. Several ischemic models of the peripheral nerve trunk have addressed the ischemic threshold below which axonal degeneration ensues (< 5ml/100 g/min). Following injury, rises in local blood flow reflect acitons of vasoactive peptides, nitric oxide, and the development of angiogenesis. In experimental diabetes, a large number of studies have documented reductions in nerve blood flow and tandem corrections of nerve blood flow and conduction slowing. A significant proportions, however, of the work can be criticized on the basis of methodology and interpretation. Similarly, not all work has confirmed that reductions of nerve blood flow are an invariable feature of experimental or human diabetic polyneuropathy. Therefore, while there is disagreement as to whether early declines in nerve blood flow "account" for diabetic polyneuropathy, there is unquestioned eveidence of early microangiopathy. Abnormalities of vase nervorum and micorvessels supplying ganglia at the very least develop parallel to and together with changes in neurons, Schwann cells, and axons.

Accompanying arteries of the cutaneous veins and cutaneous nerves in the extremities: anatomical study and a concept of the venoadipofascial and/or neuroadipofascial pedicled fasciocutaneous flap.

The arterial anatomy of the accompanying arteries of the cutaneous veins and cutaneous nerves in the extremities was investigated in 10 fresh cadavers that had been injected with a lead oxide-gelatin mixture throughout the entire body. It is well known that cutaneous nerves have neurocutaneous perforators, but it was found that cutaneous veins also have their own accompanying arteries as well. The accompanying arteries of the cutaneous veins had branches not only to the vein wall, but also to the skin, i.e., venocutaneous perforators. Based on these findings, the concept of the adipofascial pedicled fasciocutaneous flap using the accompanying arteries of the cutaneous veins, cutaneous nerves, or both was proposed.

Calcitonin gene-related peptide and peripherin immunoreactivity in nerve sheaths.

The intrinsic innervation of rat sciatic nerve sheaths was studied by means of immunohistochemical labeling for calcitonin gene-related peptide (CGRP) and peripherin. CGRP immunoreactivity (CGRP-IR) and peripherin immunoreactivity (peripherin-IR) were found in fine nerve fibers independent of nerve sheath vasculature. These findings suggest that a subset of the nervi nervorum may have nociceptive functions, and that this subset is distinct from nerve fibers that innervate the blood vessels of the nerve sheaths.

[Neuropeptides in the facial nerve of the rat]. / Neuropeptide im Nervus facialis der Ratte.

The occurrence of peptidergic nerve fibres containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) in the cerebral arteries and arterioles is well known. NPY is a vasoconstrictor, while SP, CGRP and VIP induce cerebrovascular dilatation. Vascular dysregulation of the vasa nervorum of the facial nerve is believed to be a central factor in the pathogenesis of Bell's palsy. Hilger's theory of the primary and/or secondary oedema which is followed by the vicious circle is generally accepted. It was our aim to describe the occurrence and distribution of neuropeptides in the blood vessels of the facial nerve. We examined the facial nerves of 6 male Wistar rats using the indirect immunofluorescence technique. There is not only a characteristic distribution of the neuropeptides in different parts of the facial nerves, but there are also beaded axons of sensory nerve fibers, which are localised freely in the endoneurium. These SP and CGRP containing beaded axons which densely innervate the nerve in the bony canal, are capable of inducing an oedema by neurogenic inflammation. Our findings suggest that there must be a vascular regulation in the facial nerve which is controlled by various neuropeptides.

[Vascularization of the common fibular nerve]. / Vascularisation du nerf fibulaire commun.

The vascularization of the common fibular nerve (CFN) let us suppose that one have to take anatomy and physiology of vasa nervorum in consideration in the genesis of neurologic lesions. This study is based on fresh cadavers dissections, with intra arterial injection of minimum colored latex. The results emphasize the causes of the CFN susceptibility while compression and stretching injury.

The blood supply of digital nerves: a microanatomical study of superficial and deep palmar venous networks.

In this work on vascularization of digital nerves, we have studied the anatomy of the deep network of venae comitantes of digital arteries, and the system of superficial palmar venules. 22 specimens of nerve and artery were dissected as one unit and were infused with Microfil prior to study under the microscope. The deep venous network, a satellite of the digital artery, can be classified into four types. A true network of deep venae comitantes exists in three of these four types, drained by deep veins arising from the transverse anastomotic arches between the palmar digital pedicles. Vascularization of the digital nerve is supplied by numerous anastomotic vessels connecting epineurial vessels, digital artery and the periarterial network (venae comitantes and vasa vasorum). This anatomical configuration lends itself to vascularized nerve grafting; for example, it is possible to use a nerve/artery graft taken as a unit from an amputated finger unsuitable for replantation. Two types of valves in this superficial venous network have been identified and their function is discussed.

Transperineurial arterioles in human sural nerve.

The perineurial sheath of nerve fascicles is a protective cellular layer that separates the endoneurium from the epineurium. Transperineurial arterioles (TPA) connect the endoneurial capillary plexuses to the epineurial arterial nutrient supply. Transperineurial arterioles are defined as any arteriole that is confined to a perineurial cell compartment, which would include all arterioles within the perineurium proper or within perineurial sleeves in the epi- or endoneurium. In this study of biopsied human sural nerves, three-dimensional reconstruction of one micron sections and ultrastructural analysis of step serials, we find that TPA are confined in open-ended perineurial sleeves by which they pass from the epineurium through the perineurial sheath proper into the endoneurium. Most TPA are terminal arterioles as evidenced by size (10-25 microns), morphological characteristics, and the fact that they connect with capillaries. Transperineurial arterioles gradually lose their continuous muscle coat and become post-arteriolar capillaries (PAC). Vascular segments that emerge into the endoneurium from the perineurial sleeves are generally of the PAC variety. Transperineurial arterioles and post-arteriolar capillaries are often associated with a plexus of unmyelinated nerve fibers. Axon varicosities exhibit a variety of morphologically distinct vesicles including dense-cored and a diversity of agranular vesicles. These findings suggest that TPA play a role in the neurogenic control of endoneurial blood flow.

[Paravascular structures of the major arteries of the cerebral hemispheres (electron microscopy study)]. / Paravazal'nye struktury magistral'nykh arterii bol'shogo mozga (élektronno-mikroskopicheskoe issledovanie).

The ultrastructure of the paravasal formations of the magistral arteries in the brain hemispheres has been studied: the paravasal nerve trunks (components of the external nerve plexus of the arteries, running outside the adventitia and surrounded with liquor) and the artery-stabilizing constructions--strings in the human being and in the dog. The human para-arterial nerve trunks possess the vasa nervorum system, presented by blood capillaries situating at the border of endo- and perineurium, by powerfully developed perineurium, which includes into its composition a system of basal membranes and perineural cells. In the canine para-arterial nerve trunks these formation are absent. In the string composition there are collagenous-fibrillar base represented by tightly packed fasciculi of collagenous fibers, oriented in parallel to the long axis of the string, and by stellate cells. Both the paravasal nerve trunks and the strings are surrounded with flattened cells of the endothelial sheath. They are very much alike with the arachnoidendothelial cells lining the subarachnoidal space.

The intrinsic vasculature of the lumbosacral spinal nerve roots.

The observations made in this study strongly support the concept that spinal nerve roots in general and the human lumbosacral spinal nerve roots in particular are structurally, vascularly, and metabolically unique regions of the nervous system. Peculiarities of their intrinsic vasculature and supporting connective tissue may account for suspected "neuroischemic" responses to pathologic mechanical stresses and inflammatory conditions associated with degenerative disease of the lower spine. It is hoped that the newly described features of the radicular vasa nervorum (to avoid confusion with the dissimilar blood supply of peripheral nerves, the term "vasa radiculorum" might be more accurate) may advance the understanding of certain aspects of lower spine symptomatology and provide some basis for much needed future research.

[Blood vessels in different systems of limb traction (experimental study)]. / Krovenosnye sosudy pri raznykh rezhimakh distraktsii konechnosti (éksperimental'noe issledovanie).

In the experiments performed in 108 dogs, structure of the vascular bed, elongated by means of Ilizarov's apparatus in the extremity pelvic segment, has been studied, as well as the hemostatic system under various regimens of distraction. Under a spare regimen reorientation of the microcirculatory bed links and its neural apparatus according to the lines of tension and distension forces are revealed, as well as new formation and growth of capillaries, nerve fibers and terminals. In the vessels of the muscular type, at the level of the osseous regenerate, the following changes are described: distractive rearrangement and intercalated growth (such as activation of biosynthetic processes in endothelium, adventitium and smooth muscle (SMC) cells), intensive proliferation and longitudinal reorientation of the activated SMC in the middle tunic, in the larger arteries a powerful longitudinal muscular layer is formed between the endothelium and the internal elastic membrane. The tendency for hypercoagulation, that exists at that time, is compensated by antithrombogenic and fibrinolitic blood activity. Under an elevated rate of the distraction or under an unstable fixation of the bone fragments in the apparatus, hypercoagulation is not compensated till the end of the experiment, and in the vessels, simultaneously with the distractive rearrangement, thrombosis, recalibration and obliteration are observed. The data observed and those of the literature, demonstrate that vascular adaptation to a dosed distraction is performed by means of certain rearrangements in the walls and of intercalated growth influenced by the effect of the distension forces. These phenomenon make the base of the mechanisms developing in the organism during its evolution and ontogenesis.

The autonomic innervation of the vasa nervorum.

Using catecholamine fluorescence and histochemical cholinesterase staining combined with quantitative image analysis a direct autonomic innervation of arteries, arterioles, venules, veins and arterio-venous anastomoses within peripheral nerves was demonstrated in normal as well as in chemically sympathectomized rats. The adrenergic nerves carry varicosities and were more diffused than acetylcholinesterase-containing nerves; the arteries and the arterio -venous anastomoses were more richly innervated. The findings that acetylcholinesterase-positive nerve fibres were unalterated by chemical sympathectomy and were revealed by short incubation times are indicative of a true cholinergic, and probably parasympathetic, innervation of the vasa nervorum. The possible importance of the autonomic innervation of the vasa nervorum in the pathogenesis of some diseases of peripheral nerves is discussed.

Morphologic study of the blood vessels of the superior cervical ganglion of the albino rat.

Blood vessels of the rat superior cervical ganglion were examined by both light and electron microscopy. Direct blood supply to the superior cervical ganglion was derived from a capsular plexus of vessels. Intraganglionic vessels were for the most part capillaries. Some of these capillaries appeared dilated and sinusoidal. Although the ganglion did not seem to be densely vascularized, there was sufficient distribution to accommodate the nerve cell bodies of the ganglion. Individual capillaries served groups of neurons. Occasionally, capillary loops could be observed to surround single neuron perikarya. Ultrastructural studies revealed the presence of two types of capillaries. The majority of the capillaries of the rat superior cervical ganglion demonstrated a continuous, non-fenestrated endothelium. Typical junctional complexes were found on abutting endothelial surfaces. Endothelial flaps and microvilli were also observed on the luminal surface of some of the vessels. Numerous micropinocytotic vesicles were observed on both the luminal and abluminal surfaces of the endothelium. A small number of capillaries demonstrated a fenestrated endothelium. In both types of capillaries there was a basement membrane and an extracellular space containing collagen. Perikaryal cytoplasm was separated from the extracellular space by a thick layer of satellite cell cytoplasm.