Heart in the brain: classical imaging sign in bilateral medial medullary infarction.

Bilateral medial medullary infarction is a rare type of posterior fossa stroke due to occlusion of blood supply to the anteromedial aspect of the medulla. It can be diagnosed by its classical imaging appearance - the "heart sign".

Use of angled hegar dialator for antegrade sizing of the right ventricular outflow tract in tetralogy of Fallot.

During transatrial-transpulmonary repair of tetralogy of Fallot, one of the challenges is accurately sizing the right ventricular (RV) outflow tract diameter, including the pulmonary annulus in an antegrade manner through the right atrium. This is due to the almost 90° angle between the long axis of the RV inflow through the tricuspid valve and the RV outflow through the pulmonary valve. The angled Hegar dialator, helps to accurately size the right ventricular outflow tract from the right atrium through the tricuspid valve in an antegrade manner.

An Umbrella Converse for Data Exchange: Applied to Caching, Computing, and Shuffling.

The problem of data exchange between multiple nodes with storage and communication capabilities models several current multi-user communication problems like Coded Caching, Data Shuffling, Coded Computing, etc. The goal in such problems is to design communication schemes which accomplish the desired data exchange between the nodes with the optimal (minimum) amount of communication load. In this work, we present a converse to such a general data exchange problem. The expression of the converse depends only on the number of bits to be moved between different subsets of nodes, and does not assume anything further specific about the parameters in the problem. Specific problem formulations, such as those in Coded Caching, Coded Data Shuffling, and Coded Distributed Computing, can be seen as instances of this generic data exchange problem. Applying our generic converse, we can efficiently recover known important converses in these formulations. Further, for a generic coded caching problem with heterogeneous cache sizes at the clients with or without a central server, we obtain a new general converse, which subsumes some existing results. Finally we relate a "centralized" version of our bound to the known generalized independence number bound in index coding and discuss our bound's tightness in this context.

Exploring minimally invasive options: Laparoscopic transabdominal levator transection for low rectal cancers.

Extralevator abdominoperineal excision (ELAPE) of the rectum offers wider circumferential margin and decreased rate of intraoperative tumour perforation. However, the need to change the position of the patient in between abdominal and perineal stages of the procedure and extended perineal resection result in increased morbidity and operative time. Evolving technique of laparoscopic transabdominal controlled division of levator ani muscles under direct vision could address these issues while providing all benefits of ELAPE for patients with low rectal cancers.

Osteocutaneous bone flap - a useful variant of the osteoplastic flap in pediatric patients.

Traditional teaching describes two types of bone flaps in craniotomies - 'free bone flap' and osteoplastic craniotomies. While in the former, the entire bone flap devoid of soft tissue attachments is removed, in the latter the bone flap that is turned is hinged on a pedicle of temporalis muscle with the aim of retaining its vascular supply. We describe a variant of the latter in 13 pediatric patients in whom the lower margin of the craniotomy was above the attachment of the temporalis muscle and where the bone flap was lifted with all the layers of the scalp including the skin and galea, highlighting the thought process behind its performance and the advantages of the same.

Bone flap resorption following cranioplasty in a cost-constrained scenario.

Bone flap resorption is an infrequently reported yet significant late complication of autologous bone cranioplasty. It requires serial imaging both to pick up and to monitor progression. Custom-made implants avoid this complication, but are expensive. In a resource-limited situation, when bone flaps placed in the abdomen undergo demineralisation and sutures are used to fix the flap as opposed to plates, where artificial cranial flap substitutes are prohibitively expensive and frequent postoperative imaging may not be feasible, prevention and management of this complication will continue to remain a problem.

Hemidiaphragmatic palsy following excision of cervical dumbbell neurofibroma in a patient with neurofibromatosis: Importance of assessing functional status of "non-limb" roots.

A 27-year-old male patient with neurofibromatosis type 1 who was operated on for a dumbbell neurofibroma of the cervical spine developed transient respiratory difficulty due to postoperative unilateral diaphragmatic palsy. This report emphasizes the need for preoperative assessment of residual function in involved non-limb roots, the role of intraoperative monitoring to take a decision on root sacrifice, and the need for optimizing respiratory function preoperatively, and describes a complication rarely reported in literature.

Recurrent, symptomatic, late-onset, contralateral subdural effusion following decompressive craniectomy treated by cranial strapping.

Subdural effusions following decompressive craniotomy for trauma are usually benign, ipsilateral to the craniotomy and resolve spontaneously. Far less common and more dangerous are contralateral subdural effusions causing external cerebral herniation. We report a case of recurrent contralateral effusion and highlight the management dilemmas. Arachnoid tear is probably the cause of these collections. Contralateral subdural effusions should be suspected in patients who have delayed neurological deterioration after an initial improvement particularly in the setting of increased "flap bulge" though they may also be found in patients who remain moribund after initial surgery. There are no clear-cut guidelines on their management due to their rarity. A variety of options like subduro-peritoneal shunt and drainage with simultaneous cranioplasty may be tried. In situations where resources or patient compliance is an issue, tapping the effusion followed by cranial strapping may be tried as was done in our case.

Modulation of aryl hydrocarbon receptor (AHR)-dependent signaling by peroxisome proliferator-activated receptor ß/δ (PPARß/δ) in keratinocytes.

Whether peroxisome proliferator-activated receptor ß/δ (PPARß/δ) reduces skin tumorigenesis by altering aryl hydrocarbon receptor (AHR)-dependent activities was examined. Polycyclic aromatic hydrocarbons (PAH) increased expression of cytochrome P4501A1 (CYP1A1), CYP1B1 and phase II xenobiotic metabolizing enzymes in wild-type skin and keratinocytes. Surprisingly, this effect was not found in Pparß/δ-null skin and keratinocytes. Pparß/δ-null keratinocytes exhibited decreased AHR occupancy and histone acetylation on the Cyp1a1 promoter in response to a PAH compared with wild-type keratinocytes. Bisulfite sequencing of the Cyp1a1 promoter and studies using a DNA methylation inhibitor suggest that PPARß/δ promotes demethylation of the Cyp1a1 promoter. Experiments with human HaCaT keratinocytes stably expressing shRNA against PPARß/δ also support this conclusion. Consistent with the lower AHR-dependent activities in Pparß/δ-null mice compared with wild-type mice, 7,12-dimethylbenz[a]anthracene (DMBA)-induced skin tumorigenesis was inhibited in Pparß/δ-null mice compared with wild-type. Results from these studies demonstrate that PPARß/δ is required to mediate complete carcinogenesis by DMBA. The mechanisms underlying this PPARß/δ-dependent reduction of AHR signaling by PAH are not due to alterations in the expression of AHR auxiliary proteins, ligand binding or AHR nuclear translocation between genotypes, but are likely influenced by PPARß/δ-dependent demethylation of AHR target gene promoters including Cyp1a1 that reduces AHR accessibility as shown by reduced promoter occupancy. This PPARß/δ/AHR crosstalk is unique to keratinocytes and conserved between mice and humans.

Sclerosing lymphangitis of penis - literature review and report of 2 cases.

Sclerosing lymphangitis of the penis is a condition related to vigorous sexual activity, manifesting as an asymptomatic firm cord -like swelling around the coronal sulcus of the penis. Since, it is self-limiting, only reassurance along with abstinence from sexual activity are required. In addition to reporting two new cases, we review and discuss the medical literature for this condition.

Pitching for the hitch: Neodural tenting sutures to prevent post-cranioplasty collection in a sunken craniectomy site.

Post-operative epidural collection is a commonly encountered complication following cranioplasty (CP) in a patient with a sunken skin flap. While on most occasions, the collection is small and resolves spontaneously, on occasion, it may be large enough to warrant evacuation. Further, such collections may predispose to infection and bone flap resorption. Dural hitch sutures were once used routinely in all craniotomies by tacking up the dura at the margins of the craniotomy to the surrounding pericranium to prevent post-operative epidural collection but now several surgeons use them only when deemed absolutely necessary. We describe a variation (in cases where CP is performed in patients with a sunken flap) where several sutures are passed from the neodura through the center of the bone flap (as opposed to the peripherally placed conventional hitch sutures) to obviate the dead space and prevent any post-operative collection.

Unifocal Primary Bone Lymphoma of the Lateral Mass of C1.

Primary bone lymphoma is an infrequently encountered tumor of the spine that has a better prognosis than other primary spinal malignancies. The understanding of this entity and its differences from other secondary bone lymphomas have evolved over time. The thoracic spine is the commonly reported site of the lesions. However, it is seldom considered as a first diagnosis when the patient presents to the neurosurgeon. A case of this uncommon tumor in a 68-year-old woman at an extremely rare location-the lateral mass of C1-is used to illustrate the detailed evaluation, nuances in treatment, and outcomes of primary bone lymphomas.

Posterior Fossa Craniopharyngioma Arising from the Inferior Medullary Velum.

We report the case of a 63-year-old man with a midline posterior fossa tumor and peculiar imaging features where we were unsure of the nature of the lesion preoperatively. Histopathology revealed it to be a craniopharyngioma. It appeared to arise from the inferior medullary velum, a site not described before in the literature. The previous four cases mentioned in literature and speculations on the origins in this uncommon site are discussed.

Calvarial hemangiomas: Series of 6 cases and review of literature.

Calvarial haemangiomas are benign, vascular tumours of the skull involving parietal and frontal bones. Mostly these lesions remain asymptomatic, and present with cosmetic deformity, headache, uncommon neurological symptoms and reported as case reports and case series. The radiological appearance can range from sessile growing intradiploically to globular and the lesions may extend outwards or inwards after eroding the outer and inner tables of the skull. "Sunburst appearance" and "Wagon-wheel sign" are classical radiological findings but the lesions may present simply as a lytic expansile or even sclerotic calvarial mass. Because of varied clinical presentation and atypical radiological characteristics, the final diagnosis can be clinched by histology only. In selected cases where these lesions are not cosmetically acceptable, en bloc resection with tumour free margins followed by cranioplasty is the treatment of choice. Most reports of calvarial haemangiomas in literature are in the form of case reports.

Imprint cytological diagnosis of colonic adenocarcinoma metastatic to liver.

The liver is a common visceral site for metastatic tumours. Radiological features of the liver, fine needle aspiration cytology (FNAC) and histopathological evaluation (HPE) of liver nodules have a significant role in pre-operative diagnosis of liver lesions. In an intraoperative setting, frozen section biopsy plays a major diagnostic modality but the role of imprint cytology of liver nodules is also appealing. Imprint cytology is a valuable and precise tool in diagnosing the lesions for a rapid intraoperative diagnosis. This study presents a case of colorectal cancer liver metastasis diagnosed by imprint cytology intraoperatively.

Gingko Leaf Sign: A Classical Imaging Finding in Spinal Meningiomas.

The common imaging features surgeons use to distinguish spinal meningiomas from spinal nerve sheath tumors on magnetic resonance (MR) scans include the presence of the "dural tail sign" on contrast-enhanced MR images, hypointensity of the lesion on T2 sequences, presence of calcifications, lack of extraspinal dumbbell extension, and the lack of cystic changes in the lesion. We highlight the rarely described finding-the "Gingko-Leaf" sign that is caused by the stretched denticulate ligament as it extends laterally, through the tumor, from the compressed spinal cord.

Paraspinal Gossypiboma (Textiloma) Mimicking a Soft Tissue Tumor.

Paraspinal textilomas are dreaded complications of spinal surgery and rarely reported in view of the medico-legal problems they may create. As many of them are asymptomatic and most are unreported, their true incidence is unknown. They must be kept in mind when re-operating for any mass lesion seen on magnetic resonance imaging in the vicinity of a previously operated spine. We present the case of a 40-year-old man found to have a textiloma as a result of a previous surgery, describe his imaging and histological findings, discuss the causes that might lead to the same, and enumerate preventive strategies to avoid such a complication.