Chronic itch induced by thalamic deep brain stimulation: a case for a central itch centre

Background Central itch syndrome has been previously described in conditions such as stroke. The neurophysiology of central itch syndrome has been investigated in non-human primates but remains incompletely understood. Methods We report an observational study of a rare case of severe central itch following thalamic deep brain stimulation and postulate the location of the central itch centre in humans. Results The patient was a 47-year-old female, with congenital spinal malformations, multiple previous corrective spinal surgeries and a 30-year history of refractory neuropathic pain in her back and inferior limbs. Following multidisciplinary pain assessment and recommendation, she was referred for spinal cord stimulation, but the procedure failed technically due to scarring related to her multiple previous spinal surgeries. She was therefore referred to our centre and underwent bilateral deep brain stimulation (DBS) of the ventral posterolateral nucleus of the thalamus for management of her chronic pain. Four weeks after switching on the stimulation, the patient reported significant improvement in her pain but developed a full body progressive itch which was then complicated with a rash. Common causes of skin eczema were ruled out by multiple formal dermatological evaluation. A trial of unilateral “off stimulation” was performed showing improvement of the itchy rash. Standard and normalized brain atlases were used to localize the active stimulating contact within the thalamus at a location we postulate as the central itch centre. Conclusions Precise stereotactic imaging points to the lateral portion of the ventral posterolateral and posteroinferior nuclei of the thalamus as critical in the neurophysiology of itch in humans.

Recurrence of left ventricular pseudoaneurysm after multiple mitral valve replacements

Left ventricular pseudoaneurysm (LVPA) formation is a potentially lethal complication of myocardial infarction (MI] and mitral valve (MV) replacement that requires prompt diagnosis and treatment. A female patient who had been complaining of exertional dyspnea underwent a two-dimensional transthoracic echocardiogram (TTE) which revealed a functioning mechanical MV with severe paravalvular leak, severe tricuspid regurgitation (TR) and severely elevated pulmonary artery systolic pressure. Moreover, echo-lucent space at the postero-lateral portion of the left ventricle near the MV was seen, suggestive of a large LVPA. Transesophageal echocardiography (TEE) and Computed Tomography (CT) angiography confirmed these findings. Afterwards, the patient had a surgical repair for the LVPA along with mitral and tricuspid valve (TV) replacement. Three months later, the patient presented with symptoms of congestive heart failure. The LVPA had recurred at the same location of the previous pseudoaneurysm and given the high risk for reoperating on the patient, close monitoring and medical management was deemed as a better option.

Using Particle Swarm Optimization to Compute Hundreds of Possible Directional Paths to Get Back/Stay in the Drilling Window

One of the responsibilities of a directional driller (DD) is the computation of the current bit position given the last survey station measurement, and with that information calculate the path back to plan if directional correction is needed. Having only a few minutes during a drilling connection to perform these calculations, the DD is limited to compute only a handful of possible paths that will be presented to the Drilling Engineer/Company Man. With this information, the Company Man will decide which path to follow. The present work aims to develop a computer algorithm that replicates the field knowledge of DDs but can compute hundreds of paths in less than one minute. In addition, since the objective of the trajectory correction may differ, the algorithm also can optimize for one of three goals: maximum rate of penetration (ROP), minimum tortuosity in the path, or maximum footage in the drilling target window. The paper presents examples of four different path recommendations in the lateral portion of a horizontal well. The results show the optimum recommended paths for the same position for a specific optimization goal. Finally, a comparison between the running time and number of paths computed is presented. All results were obtained during the validation tests of the algorithm.

Two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the tropical monsoon forest in southern China

Two new species of the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the tropical monsoon forest in southern China are described on the basis of an integrative taxonomic study involving morphology, karyology, histology, and molecular analyses. The new species Dugesia circumcisa Chen & Dong, sp. nov. is characterised by asymmetrical openings of the oviducts; right vas deferens opening at anterior portion of the seminal vesicle and the left one opening at mid-lateral portion of the seminal vesicle; two diaphragms in ejaculatory duct, the latter being ventrally displaced and opening at the tip of the penis papilla, which is provided with a nozzle; wide duct connecting male atrium and common atrium; chromosome complement triploid with 24 metacentric chromosomes. The other new species, Dugesia verrucula Chen & Dong, sp. nov., is characterised by the large size of the living worm, usually exceeding 3.5 cm in length; asymmetrical openings of the oviducts; subterminal opening of ventrally displaced ejaculatory duct; vasa deferentia symmetrically opening into the postero-lateral portion of the seminal vesicle; well-developed duct between the seminal vesicle and diaphragm; single dorsal bump near the root of the penis papilla; bursal canal with pleated wall and spacious posterior section; unstalked cocoons; chromosome complement diploid with 16 metacentric chromosomes. Inter-specific molecular distances and their positions in the phylogenetic tree reveal that D. circumcisa and D. verrucula are clearly separated from their congeners.

Incomplete ossification of the atlas in cats: seven cases detected on computed tomography

Defects of the ventral arch of the atlas were detected on computed tomography in nine cats aged 3…12 months with signs of upper cervical injury including paina and ataxia. Seven cats have an ambulatory tetraparesis, and two cats have a nonambulatory tetraparesis. The bone defects were consistent with the normal location of the ventral arch growth areas of the atlas. In all observed cats, the pattern of ossification abnormalities was similar — the lateral portion of the arch was completely absent in seven cats on the left and in two cats on the right. The structure of the ventral tubercle was traceable in 8 of 9 cats. Also, in 8 of 9 cases an isolated bone fragment was observed lateral to the dens of the axis, the exact origin of which was not determined. This fragment was observed in 6 cases on the right, in two cases on the left, and only in two cases it corresponded to the side of the undeveloped arch. In 7 out of 9 cats, the dorsal arch was not fused; in 2 cats with complete fusion, the dorsal arch was deformed. An dens fracture was visualized in 3 cases, no hypoplasia of the dens was visualized, and one cat have atlantoaxial subluxation. Seven cats received conservative treatment and 2 cats received surgical treatment. Clinical improvement was observed in all cats. Disorder the ossification of the ventral arch of the atlas should be considered as the differential diagnosis in young cats with suspected atlanto-axial instability and trauma of the cervical spine. The authors were unable to find publications describing this atlas developmental abnormality in cats, so the authors believe that this is the first mention of incomplete ossification of the atlas in cats.

Posterior Internal Frontal Artery Vascularization of the Precentral Gyrus Responsible for Proximal Arm Movement: Insight from a Case of Coil Migration

Our knowledge of the vascularization of the precentral gyrus by branches of the anterior cerebral artery (ACA) relies mainly on anatomical cadaveric dissection. A distal branch of the ACA known as the posterior internal frontal artery (PIFA) is thought to vascularize the precentral gyrus responsible for proximal arm movement; however, no clinical correlation has yet been reported to confirm this relation. In this manuscript, we report a case of coil migration in the PIFA, causing proximal arm weakness in a 58-year-old woman treated for aneurysmal subarachnoid hemorrhage. The occurrence of clinical signs immediately following coil migration into the PIFA, combined with evidence of stroke in the cortical territory related to arm movement as seen on imaging, indicates that the PIFA indeed can vascularize this lateral portion of the precentral gyrus. This case confirms our current understanding of the vascularization of the precentral gyrus by distal ACA branches, in particular the PIFA.

First record of Hiplyra Elegans (Gravier, 1920), (Crustacea; Decapoda; Leucosiidae) in the North-West Arabian Gulf – Iraq

The article presents the first record of the Hiplyra elegans crab — from the Leucosiidae family — on the Iraqi coast, located in the north-west Arabian Gulf - Iraq. Through the morphological characteristics of the species Hiplyra elegans, it was possible to diagnose these crabs. Such characteristics, used for classification, are: the lateral margin of the carapace posteriorly to subhepatic facet closely beaded; granules smaller posteriorly; frontal region distinctly narrowed; carapace is long thin wide; sixth somite of male abdomen smooth; elevated male telson on lateral portion; dactyl shorter than upper margin of propodus, sickle-shaped, with its inner margin smooth, Chela elongate, laterally flattened, dactyl with inner margin entire. In male surface minutely granulate, bearing perliform granules anteriorly; Lower margin of propodus granulate, line of minute granules on the inner lower surface, upper margin minutely granulates. Pereiopods slender, short. Pereiopodal meri longer than carpi and propodi; dactyli longer than propodi. Keywords: Arabian Gulf. Crabs. Crustacea. Hiplyra. Leucosiidae. Resumo O artigo apresenta o primeiro registro do caranguejo Hiplyra elegans — da família Leucosiidae— na costa iraquiana, localizada no noroeste do Golfo Pérsico - Iraque. Através das características morfológicas da espécie Hiplyra elegans, foi possível diagnosticar esses caranguejos. Tais características, utilizadas para a classificação, são: margem lateral da carapaça posterior à face sub-hepática, extremamente granulada e com grânulos menores posteriores; região frontal estreita; carapaça longa, fina e larga; sexto somito do abdômen masculino liso; télson masculino elevado na parte lateral; dátilo mais curto que a margem superior do própodo e em forma de foice; margem interna lisa; quela alongada e lateralmente achatada; dátilo com margem interna inteira; superfície masculina finamente granulada e com grânulos perliformes anteriores; margem inferior do propódio granulada; linha de grânulos minúsculos na superfície interna inferior; margem superior finamente granulada; pereiópodes delgados e curtos; pereiópodes merus mais longos que o carpo e propódio; dátilo mais longo do que propódio. Palavras-chave: Golfo Pérsico. Caranguejos. Crustacea. Hiplyra. Leucosiidae. Resumen El artículo presenta el primer registro del cangrejo Hiplyra elegans — de la familia Leucosiidae — en la costa iraquí, ubicada en el noroeste del Golfo Pérsico – Irak. A través de las características morfológicas de la especie Hiplyra elegans, fue posible identificar esos cangrejos. Tales características, utilizadas para la clasificación, son: borde lateral del caparazón posterior a la región sub-hepática, extremadamente granulada y con gránulos menores posteriores; región frontal angosta; caparazón largo, fino y ancho; sexto segmento del abdomen masculino liso; telson masculino elevado en la parte lateral; dactilo más corto que el borde superior del propodo y en forma de hoz; borde interno liso; quela alargada y lateralmente aplanada; dactilo con borde interno entero; superficie masculina finamente granulada y con granos perliformes anteriores; borde inferior del propodo granulado; línea de gránulos minúsculos en la superficie interna inferior; pereiópodos delgados y cortos; pereiópodos meros más largos que el carpo y el propodo; dactilo más largo que el propodo. Palabras-clave: Golfo Pérsico. Cangrejos. Crustacea. Hiplyra. Leucosiidae.

Quantitative analysis of ipsilateral and contralateral supracerebellar infratentorial and occipital transtentorial approaches to the cisternal pulvinar: laboratory anatomical investigation

OBJECTIVEThe cisternal pulvinar is a challenging location for neurosurgery. Four approaches for reaching the pulvinar without cortical transgression are the ipsilateral supracerebellar infratentorial (iSCIT), contralateral supracerebellar infratentorial (cSCIT), ipsilateral occipital transtentorial (iOCTT), and contralateral occipital transtentorial/falcine (cOCTF) approaches. This study quantitatively compared these approaches in terms of surgical exposure and maneuverability.METHODSEach of the 4 approaches was performed in 4 cadaveric heads (8 specimens in total). A 6-sided anatomical polygonal region was configured over the cisternal pulvinar, defined by 6 reachable anatomical points in different vectors. Multiple polygons were subsequently formed to calculate the areas of exposure. The surgical freedom of each approach was calculated as the maximum allowable working area at the proximal end of a probe, with the distal end fixed at the posterior pole of the pulvinar. Areas of exposure, surgical freedom, and the working distance (surgical depth) of all approaches were compared.RESULTSNo significant difference was found among the 4 different approaches with regard to the surgical depth, surgical freedom, or medial exposure area of the pulvinar. In the pairwise comparison, the cSCIT approach provided a significantly larger lateral exposure (39 ± 9.8 mm2) than iSCIT (19 ± 10.3 mm2, p < 0.01), iOCTT (19 ± 8.2 mm2, p < 0.01), and cOCTF (28 ± 7.3 mm2, p = 0.02) approaches. The total exposure area with a cSCIT approach (75 ± 23.1 mm2) was significantly larger than with iOCTT (43 ± 16.4 mm2, p < 0.01) and iSCIT (40 ± 20.2 mm2, p = 0.01) approaches (pairwise, p ≤ 0.01).CONCLUSIONSThe cSCIT approach is preferable among the 4 compared approaches, demonstrating better exposure to the cisternal pulvinar than ipsilateral approaches and a larger lateral exposure than the cOCTF approach. Both contralateral approaches described (cSCIT and cOCTF) provided enhanced lateral exposure to the pulvinar, while the cOCTF provided a larger exposure to the lateral portion of the pulvinar than the iOCTT. Medial exposure and maneuverability did not differ among the approaches. A short tentorium may negatively impact an ipsilateral approach because the cingulate isthmus and parahippocampal gyrus tend to protrude, in which case they can obstruct access to the cisternal pulvinar ipsilaterally.

Developmental anomalies of the lateral portion of the cervical neural arch: Multimodal imaging and clinical implications

Objective This study aimed to describe the imaging spectrum of developmental anomalies of the lateral portion of the cervical neural arch. Method This was a five-year retrospective review of consecutive computed tomography (CT) scans of the cervical spine for structural anomalies of the cervical vertebral pedicle and facets. CT, radiographs and, when available, magnetic resonance imaging studies were independently reviewed. Anomalies were grouped into the following three categories: the absence of a pedicle, clefts in the vertebral arch or isolated dysmorphism of the facet. Clinical data on demographics and neurological outcomes were documented. Results Among 9134 consecutive patients undergoing a CT scan of the cervical spine, 18 (0.2%) patients were found to have developmental anomalies of the pedicle and facets. Findings included 7/18 (39%) with congenital absence of a pedicle, 8/18 (44%) with clefts in the vertebral arch and 3/18 (17%) with isolated dysmorphism of the articular facets. No acute neurological deficits or spinal cord injuries were reported. Associated chronic symptoms included neck pain 10/18 (56%), radiculopathy 7/18 (39%) and myelopathy 1/18 (6%). Conclusion Developmental anomalies of the pedicle and facet may mimic traumatic spinal pathologies. Recognising a diverse spectrum of imaging findings is vital to prevent misdiagnosis and unnecessary intervention.

Unusual Subcutaneous Presentation of Cavernous Hemangioma in the Lower Eyelid

Purpose: To report a patient with cavernous hemangioma (CH) presenting as a “subcutaneous” lower eyelid mass. Case report: A 37-year-old man presented with a painless and palpable mass over the right lower eyelid for two years prior to referral. Computed tomography scan revealed a well-defined, lobulated mass located in the mid and lateral portion of the lower eyelid that extended posteriorly to the anterior orbital space. A transcutaneous excisional biopsy was performed. Histopathologic findings of the tumor confirmed CH. Most CHs are intraconal lesions, making our case an unusual presentation for this condition. Conclusion: CH may present superficially in the eyelid and anterior orbital area and thus, although this location is not common, it should be kept in mind as a differential diagnosis for any well-defined eyelid tumor.