High bifurcation of the brachial artery.

Variations of the arterial pattern in the upper limb are quite common in humans. In the present study, we describe two cases of high bifurcation of the brachial artery. In the first cadaver both branches run superficially along the arm and were also located superficially at the antecubita fossa. In the second cadaver the branch that continues as the radial artery in the forearm run superficially and was located also superficially at the antecubita fossa, while the second branch had a more or less normal distribution. The embryological basis and clinical significance are discussed.

The safest electrode trajectory for deep brain stimulation of the human nucleus accumbens: a stereotactic anatomic study.

BACKGROUND: The primary purpose of our stereotactic anatomic study was to determine the safest electrode trajectory for deep brain stimulation (DBS) of the human nucleus accumbens (NA). Considering NA DBS together with the complications related to surgical implantation and based on methods for assessing the electrode trajectory we tried to reveal the secret of a trajectory for targeting the NA with the highest possible level of safety. MATERIAL AND METHODS: Our material consisted of 30 cerebral hemispheres we have in our Department from cadaver donors for students' education. We identified the electrode's target point in coronal sections. As safe we considered a trajectory from the cerebral cortex to the NA, which traverses the anterior limb of the internal capsule (AIC) without passing through either the caudate nucleus or putamen. We measured the minimum, maximum and safest coronal angles of the electrode trajectory (between the trajectory and the midline), as well as the AIC angle and width of the trajectory angle. We also measured trajectory projection length from the cerebral surface to the superior (d1) and inferior (d2) margins of the NA. RESULTS: The safest trajectory angle for NA DBS was found to have a mean value of 29.10 degrees, ranging from 23.80 to 35.40 degrees. The mean AIC angle was 33.78 degrees. We found no statistically significant difference between right and left hemispheres and a strong statistical relation between the safest electrode trajectory and AIC angle. Mean values of d1 and d2 were found to be 53.57 mm and 60.86 mm respectively. The mean value of the length of the electrode trajectory in coronal projection within the NA (d2-d1) was found to be 7.29 mm. CONCLUSION: The new knowledge that our stereotactic anatomic study offers is a definition of the safest electrode trajectory for NA DBS, its coronal angle width, as well as an estimation of its length.

The human nucleus accumbens as a target for deep brain stimulation: anatomic study of electrode's target point and stereotactic coordinates.

INTRODUCTION: The nucleus accumbens (NA), a "pleasure center", is the most inferior part of the ventral striatum. NA, related to the limbic and extrapyramidal motor system, is involved in some of the most common neuropsychiatric disorders. Nowadays it is a target for deep brain stimulation (DBS), in some carefully selected patients. Our purpose was to evaluate the accuracy of its position within the NA, in relation to the stereotactic target point that is today used. METHODS AND MATERIALS: We identified, studying 25 cerebral hemispheres, the target point of the NA DBS electrode, at a specific level that is important for its imaging. We also identified the stereotactic coordinates of the NA and made a statistical analysis and comparisons. RESULTS: We found that in 3 out of 25 cases, the used stereotactic coordinates fail to offer a target point within the limits of the NA. DISCUSSION: We present the first stereotactic anatomic study evaluating the precise position where the electrode for human NA DBS is to be placed and the only anatomic study of the human NA performed on such a large number of cases. The stereotactic coordinates used for NA DBS are accurate. However, we suggest that the electrode's final position should be considered to be slightly less deep.

Sectioning of filum terminale externum using a rigid endoscope through the sacral hiatus. Cadaver study.

AIM: Tethered cord syndrome (TCS) is a stretch-induced functional disorder of the spinal cord, which is directly related to filum fixation. Classic surgical approaches to the filum involve open surgery and include varying amounts of spinal bone removal. In an effort to reduce the morbidity and mortality of these procedures, the authors explored a less invasive method. They evaluated the ability, safety and feasibility for endoscopic sectioning of the filum terminale externum by performing upward orientated navigation in the extradural sacral spinal canal through the sacral hiatus using a rigid endoscope. METHODS: Four adult, phenol-formalin embalmed cadavers were used for endoscopic section of the filum terminale externum at the tip of thecal sac. After preparing the anatomical area of sacral hiatus, a rigid endoscope (Storz, of 3.8 mm external diameter with two working channels, of 1 mm each, one for suction-irrigation and one as working) was inserted into the extradural sacral spinal canal and the filum terminale externum was identified and cut easily at the distal end of thecal sac at the level of S2. In all cases, it was possible to manipulate the rigid endoscope and inspect the full length of the extradural sacral spinal canal, especially at the S1-S2 level. RESULTS: The results indicate that the tested transhiatal approach for upward orientated extradural endoscopy represents a minimally invasive procedure that provides an appropriate and feasible route to the extradural sacral spinal canal. CONCLUSION: Such approach is an attractive alternative for filum terminale externum sectioning in cases where tethered cord syndrome is not accompanied by any other pathology. Moreover if filum terminale internum sectiong is indicated, it can be performed in second stage.

Dolichoectatic cervical arteries (carotid and vertebral arteries) heralded by recurrent cerebral ischemia: case illustration.

A case of a 61-year-old man with recurrent episodes of cerebral transient ischemic attacks is reported. The patient had a history of cigarette smoking, hypertension, hypercholesterolemia, and diabetes mellitus. Before these episodes, the patient had no clinical symptoms and signs of cerebral pathology. Brain magnetic resonance imaging revealed microvascular lesions in the white matter of the cerebral hemispheres. Digital subtraction arteriogram revealed the aortic arch dolichoic shape and course of the great vessels originating from it, whereas there were no pathological findings from the intracranial vessels. This study describes a case of the existence of distal dolichoectasia of the vertebral and carotid arteries without intracranial dolichoectasia. It seems that such a type of dolichoectasia does not influence the performance status of a patient, but when a critical point is crossed, patients suffer from cerebrovascular disease.

Temporal bone study of development of the organ of Corti: correlation between auditory function and anatomical structure.

OBJECTIVE: To study the development of the organ of Corti in the human cochlea, and to correlate our findings with the onset of auditory function. MATERIAL AND METHODS: Step sections of 81 human fetal temporal bones were studied, from eight weeks of gestation to full term. RESULTS: By the end of the 10th week, the tectorial membrane primordium could be traced even in the most apical turns. Individual hair cells became identifiable at the basal turn at 14 weeks. At the same time, a small but well formed oval space was observed between the inner and outer hair cells in the basal turn. This does not correspond to the tunnel of Corti, as is erroneously quoted in the literature, as the individual pillar cells develop at later stages. Between 14 and 15 weeks, Hensen's cells were recognised for the first time. Individual pillar cells were identifiable at 17 weeks and the tunnel of Corti opened at 20 weeks. By 25 weeks, the cochlea had reached its adult size, but continued to develop until full term. DISCUSSION AND CONCLUSIONS: A temporal coincidence of different developmental events is responsible for early fetal audition at 20 weeks, including growth of pillar cells, opening of the tunnel of Corti and regression of Kollicker's organ, with the subsequent formation of the inner spiral sulcus and then separation of the tectorial membrane. The fine structures of the organ of Corti continue to develop well after the 25th week, and this may well alter the mechanical properties of the vibrating parts of the cochlea, which may in turn account for the frequency shift observed in preterm infants. These changes will have to be taken into account in the development of prenatal hearing screening tests.

Middle cranial fossa endoscopy using a rigid endoscope.

Trigeminal neuralgia (TN), also known as tic douloureaux, is a craniofacial pain disorder which is typically associated with acute-onset severe pain on one side of the face usually. The condition is characterized by intermittent unilateral pain affecting the lower face and jaw. Although many potential causes have been implicated, in many patients the etiology remains obscure. Initially, patients with trigeminal neuralgia should be offered conservative medical management. If surgery is necessary, the simplest and least hazardous procedure should be chosen. The goals of modern surgical therapy are: Long-term pain control, minimal to no morbidity, and as low a mortality risk as possible. In this study, we attempted to perform middle cranial fossa endoscopic exploration in four adult phenol-formalin embalmed cadavers, using a rigid endoscope with 3.8 mm external diameter and two working channels of 1 mm in diameter each (Karl Storz, Tuttlingen, Germany), inserted through a burr-hole centered at the base of the middle cranial fossa, 1 cm in front and 1 cm upwards of the tragus. Our objective was to determine if this approach provides adequate access to the trigeminal ganglion for possible dissection of V2 and V3 trigeminal roots, the two typically radiating sites of TN. In all four cadavers, middle cranial fossa exploration was possible without difficulties. We offer this approach as a minimally invasive surgical procedure to access the trigeminal ganglion, for potential use as another alternative for the surgical management of medically refractory trigeminal neuralgia.

Endoscopic anatomy of the thecal sac using a flexible steerable endoscope.

In this study the ability for upward-orientated endoscopic visualization of thecal subarachnoid space using a flexible steerable endoscope was evaluated in order to compare endoscopic anatomical findings with the already known macroscopic ones of the incontained structures and to test the approach for clinical employment. For this purpose, four adult phenol-formalin embalmed cadavers were used and the approach selected was through a laminectomy window at the S1-S2 level. The dura mater was opened and a flexible steerable endoscope (Storz, of 2.8 mm external diameter with one working channel) was inserted subarachnoidally for upward-orientated observation of the content of thecal sac. By using this approach filum terminale, lower lumbar, sacral and coccygeal nerve rootlets were identified and observed in detail. By moving the endoscope even more upwards, inspection of the upper part of the thecal subarachnoid space and conus medullaris was also possible. The findings collected from the study indicate that this approach for upward-orientated intradural subarachnoid endoscopy gives an appropriate working and inspecting window to the lower, as well as to the upper part of the thecal subarachnoid space and even of the conus medullaris. Furthermore, inspection and identification of lower lumbar, sacral and coccygeal nerve rootlets is possible and efficient and the endoscopic anatomical observations coincide with the already known gross-anatomical ones.

Anomalous origin of circumflex artery from right sinus of Valsalva: a rare cause of non-ST elevation syndrome.

We present a case with anomalous origin of the left circumflex artery from the right coronary artery ostium, which caused a non-ST elevation coronary syndrome. A review of the literature indicates this to be an extremely rare case.

Idiopathic temporal bone encephalocele.

Meningoencephaloceles are herniations of brain tissue through dehiscences of the skull base. These skull defects are either acquired (otologic infection, trauma, surgery, neoplasia) or spontaneous. Spontaneous temporal bone meningoencephaloceles are quite rare conditions, usually congenital in origin presenting during childhood, and only occasionally idiopathic presenting during adulthood. We present a case of temporal bone meningoencephalocele of adult onset. The patient was treated with exploratory mastoidectomy, amputation of the herniated cele and closure of the defect with temporalis fascia and an inferiorly based pedicled muscular flap. No reconstruction of the bony defect was performed, as the layered closure was considered adequate. Twelve months' follow-up revealed no relapse of the condition or postoperative complications.

H3 Propranolol serum levels following lidocaine administration in rats with CCL4 induced liver damage.

Liver disease alters the pharmacokinetic and pharmacodynamic properties of hepatically eliminated drugs. The main factors influenced are plasma albumin levels, enzyme balance (induction & inhibition) and drug binding to tissue proteins. The influence of lidocaine on serum, heart and liver propranolol levels in Wistar rats after liver injury induced by carbon tetrachloride CCl4 0.4 ml/kg x 2/wkl, was investigated. 40 male Wistar rats were divided into four groups (I, II, III, IV; n=10), Group I animals received only propranolol (labelled + cold substance) 40 mg/kg/12 h p.o., group II propranolol plus lidocaine in a single dose of 4mg/kg s.c., group III was treated with CCl4 for 6 weeks and received propranolol x2 at the same dosage as group I, while group VI was treated with CCl4 and the same drug dosage as group II. The simultaneous administration of H3-propranolol and lidocaine increased propranolol levels in the serum and tissues. The liver in damaged animals showed an increase of propranolol level under lidocaine co-administration, probably due to CCl4 induced liver enzyme activity, resulting in a rapid propranolol metabolism or to competition between both drug protein binding sites. The increased propranolol levels in the heart after lidocaine administration were probably due to attributed to its high affinity for heart tissue. Consequently, as regards the therapeutic approach for patients with liver disease receiving propranolol their propranolol dosage should be reduced when lidocaine is co-administered.