Substantial Volume Changes and Plan Adaptations During Preoperative Radiation Therapy in Extremity Soft Tissue Sarcoma Patients

Purpose

Many authors suggest that extremity soft tissue sarcomas (ESTS) do not change significantly in size during preoperative radiation therapy (RT). This cone beam computed tomography study investigates the justification to deliver the entire course with 1 initial RT plan by observing anatomic changes during RT.

Delusional parasitosis as presenting symptom of occipital lobe cerebrovascular accident

Delusional parasitosis manifests as a fixed, false belief that an individual is infested by living organisms. Primary delusional parasitosis is a psychiatric disorder with the delusion as an isolated manifestation, whereas secondary delusional parasitosis is a delusion occurring secondary to a psychiatric disorder, substance use, or medical illness. A 62-year-old woman with no psychiatric history presented to the Emergency Department with two to three months of “whole body itching” and seeing small insects crawling on her skin and in her hair. Exam of her skin and scalp was notable for no appreciable lesions, rashes, excoriations, or insects. Her neurologic exam was notable for full visual fields, and no localizing deficits. A non-contrast head CT demonstrated a nonspecific heterogeneous low-attenuation lesion within the medial right occipital lobe, and a follow up MRI confirmed a right posterior cerebral artery distribution subacute infarction. She was admitted for two days, and ultimately was discharged on aspirin and atorvastatin for secondary prevention. An emergency physician should remain vigilant in his/her assessment of patients with seemingly psychiatric symptoms, in particular elderly patients with no known psychiatric illnesses. Neuroimaging should be amongst studies considered in the evaluation of elderly patients presenting with new onset psychiatric complaints.     

Robotic left-sided colorectal resection with natural orifice IntraCorporeal anastomosis with extraction of specimen: The NICE procedure. A pilot study of consecutive cases

Background

Despite numerous benefits, only a small fraction of laparoscopic left-sided colectomy is accomplished without the need for an abdominal incision to retrieve the specimen and prepare for anastomosis. We report our early experience with a robotic approach using Natural orifice IntraCorporeal anastomosis with Extraction of specimen (NICE) to help overcome the technical limitations and challenges of this approach.

The mutational landscape of melanoma brain metastases presenting as the first visceral site of recurrence

Brain metastases are a major cause of melanoma-related mortality and morbidity. We undertook whole-exome sequencing of 50 tumours from patients undergoing surgical resection of brain metastases presenting as the first site of visceral disease spread and validated our findings in an independent dataset of 18 patients. Brain metastases had a similar driver mutational landscape to cutaneous melanomas in TCGA. However, KRAS was the most significantly enriched driver gene, with 4/50 (8%) of brain metastases harbouring non-synonymous mutations. Hotspot KRAS mutations were mutually exclusive from BRAF^V600, NRAS and HRAS mutations and were associated with a reduced overall survival from the resection of brain metastases (HR 10.01, p = 0.001). Mutations in KRAS were clonal and concordant with extracranial disease, suggesting that these mutations are likely present within the primary. Our analyses suggest that KRAS mutations could help identify patients with primary melanoma at higher risk of brain metastases who may benefit from more intensive, protracted surveillance.Subject terms: CNS cancer, Metastasis, Melanoma, Tumour biomarkers, Cancer     

Functional Status Is Associated With 30-Day Potentially Preventable Readmissions Following Skilled Nursing Facility Discharge Among Medicare Beneficiaries

Objectives

The objectives of this study were to determine the association between patients’ functional status at discharge from skilled nursing facility (SNF) care and 30-day potentially preventable hospital readmissions, and to examine common reasons for potentially preventable readmissions.

Characterization of root surface periodontal ligament following avulsion, severe intrusion or extraction: preliminary observations

Abstract –  This study employed novel topographic and histological techniques to assess remaining periodontal ligament (PDL) in a convenience sample of avulsed and intruded human permanent incisors and extracted premolars. Seventeen human teeth (eight avulsed, five severely intruded and four uninjured extracted) were evaluated for the distribution and physical characteristics of adherent root surface PDL. The topographic distribution of PDL was assessed by staining roots with malachite green and determining the proportion of remaining PDL within selected regions on four aspects of each tooth. In order to characterize mechanical damage to PDL, serial transverse sections of roots were stained with hematoxylin and eosin and examined at magnifications of 40× to 800×. The sections were photographed and imaging software was used to calculate the percentage of remaining PDL in the circumference of each root section. Topographic analysis demonstrated that 54% of the PDL remained on roots of avulsed and severely intruded incisors and 36% of the PDL remained on the extracted single-rooted premolars. Examination of serial transverse root sections revealed that 58% of the PDL remained on roots of avulsed or severely intruded incisors and 54% on extracted premolars. Avulsed and severely intruded incisors demonstrated similar amounts of retained PDL. In both injuries, almost half of the root surface was denuded of PDL.     

Three-dimensional finite element analysis of implant stability in the atrophic posterior maxilla: a mathematical study of the sinus floor augmentation

Sinus lifting is performed with a variety of materials and techniques without a precise knowledge of the quantity of augmentation. This study based on three-dimensional finite element analysis was designed to show which surgical procedure and which amount of peri-implant packing yields the best bony support for dental implants. Eight 3D-FE models were used. Four modeled standard situations simulated quantitatively different packing situations produced by differences in surgical approach: i. no packing; ii. thin 1 mm bony sheath; iii. oblique subcomplete packing; iv. complete bony peri-implant packing up to the implant end. A fifth model compared a standard implant with a length of 13.5 mm and a diameter of 3.75 mm with a 7-mm-long and 5-mm-thick implant. In three additional models the stress response of the bone-implant system was evaluated in the absence of a cortical layer, thus simulating an extreme degree of maxillary atrophy. In all models the modeled implants were loaded at their points of emergence with an assumed force of 100 N. The vector of the loading force was inclined 30 degrees posteriorly relative to the implant axis and 30 degrees away from the sagittal plane. The bone-implant interface was assumed to be perfect simulating full osseointegration. The final evaluation of the FE models showed complete peri-implant packing to reduce displacements of the implant tip by 32% vs. no sheathing/packing. Van Mises' equivalent stresses were used to assess the stresses in both human bone and titanium alloy implants. The highest stress levels in bone were predicted for the case without sufficient implant sheathing. In the models with adequate bony implant support, intrabony stresses were generally reduced by up to - 40%. The structural stiffness of the bone-implant system increased with the extent of sinus floor elevation. The results indicate that more extensive peri-implant packing reduces implant displacement, intrabony stresses and stresses at the bone-implant interface.     

Porous hydroxyapatite for grafting the maxillary sinus in sheep: comparative pullout study of dental implants

PURPOSE: In this experimental study, dental implants placed after maxillary sinus grafting with either porous hydroxyapatite (HA) (Interpore 200) or autogenous bone were examined for their mechanical stress tolerance. MATERIALS AND METHODS: A total of 54 titanium plasma flame-sprayed cylindric implants were placed in the lateral sinus wall bilaterally of 27 mountain sheep. The bony sinuses were opened through an extraoral approach. Eighteen sinuses were grafted with porous HA, and another 18 were grafted with cancellous bone from the iliac crest. Eighteen non-grafted sinuses were used as controls. In the same operation, 2 cylindric implants were placed in each of the sinuses. One implant of each sinus was tested for mechanical strength of the bone-implant interface at 12, 16, and 26 weeks using pullout force. RESULTS: The mean pullout force was 259.3 N in the control group, 356.7 N in the autogenous bone group, and 376 N in the HA group. Pooled data for the grafted sites showed the pullout force to be significantly higher than in the empty control sites (P = .02). The pullout force increased significantly with ongoing healing time (P = .02), but there was considerable variation within the groups. While the force remained more or less constant throughout the follow-up time in the controls (248 N at week 12 to 276 N at week 26), it increased dramatically in the group augmented with autogenous bone (223.8 N at week 12 to 523.16 N at week 26). The pullout force was initially highest in the HA group (302.3 N at week 12) and increased to 423.5 N at 26 weeks, but it did not reach the levels recorded in the autografted group. DISCUSSION AND CONCLUSION: Mechanical tests of bone-to-implant contact in a sheep model showed that HA for 1-stage sinus floor elevation significantly increased the pullout force versus ungrafted sinuses, although it was less than that found with autogenous bone after 26 weeks.