Contiguous Fashion Research Articles

Use of Flow-through Free Flaps in Head and Neck Reconstruction.

Reconstructive obstacles in composite head and neck defects are compounded in reoperated, traumatized, irradiated, and vessel-depleted surgical fields. In cases that require multiple free flaps, recipient vessel accessibility and inset logistics become challenging. Strategic flow-through flap configurations mitigate these issues by supplying arterial inflow and venous outflow to a second flap in a contiguous fashion. This approach (1) permits the use of a singular native recipient vessel, (2) increases the reach of the vascular pedicle, avoiding the need for arteriovenous grafting, and (3) allows for a greater three-dimensional flexibility in configuring soft tissue and bony flap inset. To demonstrate this technique, we conducted a retrospective review of all head and neck reconstruction patients presenting to us from March 2019 to April 2021. We present seven oncological and two traumatic patients (N = 9) who received flow-through free flaps for head and neck reconstruction. The most common flap used as the flow-through flap was the anterolateral thigh flap (N = 7), followed by the fibula flap (N = 2). Mean follow-up time was 507 days. No flap failures occurred. In head and neck reconstruction, the use of the flow-through principle enables uninterrupted vascular flow for two distinct free flaps in single-stage reconstruction for patients with vessel-depleted, irradiated, and/or reoperated fields. We demonstrate that flow-through flaps in the head and neck may be used successfully for a variety of cases and flaps.

Distributed strain monitoring of overburden delamination propagation at a deep longwall mine

Clear understanding of overburden failure propagation during underground mining is critical in managing safety and environmental issues such as rock burst hazards, groundwater inrush and longwall convergency. This paper presents an in-situ monitoring study of overburden strain dynamics at a kilometre-deep longwall mine using distributed fibre optic sensing technology (DFOS). A deep borehole was drilled from the ground surface to near the mining seam and installed with an optical fibre cable to detect rock deformation in a contiguous fashion. In addition, a Global Navigation Satellite System (GNSS) device was installed at the borehole collar to monitor surface subsidence. The results suggested that strata delamination contiguously extended to 347 m, about 34 times the mining thickness. The remaining 600 m thick strata above this height behaved as the intact zone. Such an overburden deformation pattern resulted in minor surface subsidence of only 0.6 m or 6% of the mining thickness. A step-wise, upward breakage of the optical fibre cable (due to excessive strain) was observed and found to correlate with other ground behaviours, including an increase in the total microseismic energy and periodic weighting on the longwall supports. These observations corroborate that the dynamic deformation of overburden is primarily governed by competent stratum units, i.e., the key strata. The monitoring results have served to develop a reliable mine-scale 3DEC model for predicting stress redistributions in the subsequent longwall panels for preventing dynamic hazards. The study also demonstrates that DFOS-based strain monitoring can be a valuable tool to investigate overburden responses to mining and has significant potential for applications in various mining methods, such as block caving, sub-level caving and open stopping.

Stereoretentive Formation of Cyclobutanes from Pyrrolidines: Lessons Learned from DFT Studies of the Reaction Mechanism.

The stereoselective synthesis of cyclobutanes that possess an array of stereocenters in a contiguous fashion has attracted the wide interest of the synthetic community. Cyclobutanes can be generated from the contraction of pyrrolidines through the formation of 1,4-biradical intermediates. Little else is known about the reaction mechanism of this reaction. Here, we unveil the mechanism for this stereospecific synthesis of cyclobutanes by means of density functional theory (DFT) calculations. The rate-determining step of this transformation corresponds to the release of N2 from the 1,1-diazene intermediate to form an open-shell singlet 1,4-biradical. The formation of the stereoretentive product is explained by the barrierless collapse of this open-shell singlet 1,4-biradical. The knowledge of the reaction mechanism is used to predict that the methodology could be amenable to the synthesis of [2]-ladderanes and bicyclic cyclobutanes.

Monitoring Road maintenance using video-geotagging in geographical information system: an innovative approach

Maintenance of roads is a key concern for smooth flow of traffic and goods for any economy to thrive. The maintenance part has been limited in GIS to information collected through ground-based surveys, GPS location of affected road area, uploading geo-tagged photos shared by public through mobile app on GIS data. The present work focuses on one such innovative approach using geo-tagging of videos of road surface with Road layer in GIS. Stretches of road in and around Ludhiana city of Punjab to reflect different scenarios such as roads located in open village area, highways, and broad and congested city roads have been used for understanding condition of surface of road in a contiguous fashion.

S2067 Mesalamine Hypersensitivity Induced Hemorrhagic Shock

Introduction: 5-Aminosalicylic acid (mesalamine) rarely induces hypersensitivity. It is first line therapy for treatment of ulcerative proctitis. However, the journal of gastroenterology and hepatology states 12% of patients are unable to tolerate mesalamine or other compounds of 5-aminosalicylic acid. The most common side effects are identified as headache, nausea, abdominal pain, and mild watery diarrhea. This case report highlights the importance of recognizing mesalamine hypersensitivity in patients with ulcerative colitis. Case Description/Methods: A 62-year-old man with history of hypertension, hyperlipidemia, chronic kidney disease stage 3B and ulcerative proctitis presented to the ED with abdominal pain (intensity 9/10), rectal pain, tenesmus, flatulence, persistent bloating, and bright red blood per rectum of 2 months duration. Colonoscopy showed diffuse moderate mucosal changes with congestion, erythema, friability, and loss of vascularity in the rectum extending in a contiguous fashion from 10 cm to anal canal. Pathology reported nonspecific chronic inflammation with hyperplastic epithelial changes but negative for dysplasia or malignancy. He began oral mesalamine and mesalamine suppository therapy. With symptomatic improvement he was discharged home and was readmitted 3 days later with worsening hematochezia. He began intravenous steroids and his mesalamine therapy was changed to balsalazide. During the next 24 – 48 hours, he started having increased hematochezia with blood clots associated with increased rectal pain (pain scale 10/10). His vital signs were recorded as temperature 97.3F, blood pressure 58/32, heart rate 42, respiratory rate 9 and saturation of 86% on room air. His hemoglobin dropped from 9.6 to 7.7. He was resuscitated with IV fluids and PRBC transfusion. His blood pressure and heart rate normalized. At that point he was diagnosed with 5-ASA hypersensitivity. All his mesalamine products were discontinued and hydrocortisone suppositories began with continuation of his IV steroids. He improved and was discharged home with a steroid taper and daily hydrocortisone suppositories (Figure 1). Discussion: 5-aminosalicylic acid (mesalamine) is currently the first line therapy for treatment of ulcerative proctitis. Although mesalamine hypersensitivity is not common, it is important to include it in the differential diagnoses of patients with pertinent inflammatory bowel disorders who present with worsening clinical symptoms after introduction to mesalamine or similar 5-aminosalicylic acid compounds.Figure 1.: A, CT A/P w/o IV contrast demonstrating edematous rectum with perirectal fat stranding suggesting proctitis. B, diffuse area of severely hemorrhagic and ulcerated mucosa in the rectum.

Effectiveness of sigmoidoscopy for assessing ulcerative colitis disease activity and therapeutic response.

Ulcerative colitis (UC) typically begins in the rectum and progresses proximally in a contiguous fashion without skip lesions. Post-treatment inflammation distribution can change over time. Colonoscopy is unpleasant for the patient and clinical trials often use sigmoidoscopy for evaluation of disease severity. The aim of this study is to evaluate whether sigmoidoscopy is adequate to assess disease activity and therapeutic response as colonoscopy.We retrospectively reviewed patients who underwent colonoscopy for the initial diagnosis and follow-up by evaluating their mucosal inflammation in our hospital from January 2012 and December 2017.A total of 69 patients were analyzed. During follow up, the inflamed segment changed post-treatment in 62% (43/69). Extensive UC was common in the changed disease extent group (P < .01). Patients treated with oral mesalazine had a higher rate of changed disease extent (P < .01). The sigmoid segment was the most commonly involved segment, and the rectum was the severely inflamed segment during initial diagnosis and follow-up. According to Mayo endoscopic subscore (MES) in the most severely inflamed colonic and rectosigmoid segment, there were high degrees of correlation in the initial UC diagnosis (r = .90, P < .01) and follow-up (r = .74, P < .01).Our findings suggest that sigmoidoscopy is effective as colonoscopy for detecting disease activity and evaluating therapeutic response in UC patients during follow-up.

Multimaterial and Multilayer Direct Digital Manufacturing of 3-D Structural Microwave Electronics

Direct digital manufacturing (DDM) is an emerging technology that is finding its place across a wide array of industries and applications as a cost-effective solution for low volume and mass customizable production. This technology encompasses a class of digital manufacturing techniques which can be combined to enable multimaterial fabrication and postprocessing. One of the promising applications for DDM is structural electronics, where lightweight printed plastics provide mechanical support as a fixture, package, or structural member and also host the electrical interconnects and devices, all in a contiguous fashion. Microwave structural electronics is a specific class of such systems for which the printing resolution as well as electrical and surface properties of the materials are especially important. This paper presents the current state of DDM technology, fundamental research into the electrical and mechanical properties of as-printed structures, and novel 3-D printed structures operating from C-band through Ku-band.

Switching Selectivity of α-Enolic Dithioesters: One Pot Access to Functionalized 1,2- and 1,3-Dithioles

An operationally simple cascade protocol has been developed for the construction of 1,2- and 1,3-dithiole derivatives from α-enolic dithioesters. 1,2-Dithioles are achieved by the reaction of dithioesters with elemental sulfur in the presence of InCl3 under solvent-free conditions. 1,3-Dithioles have been constructed via DABCO mediated self-coupling of dithioesters in open air enabling the formation of two new C-S bonds and one ring in a single operation in contiguous fashion. The reactions proceeded smoothly affording the desired sulfur-rich heterocycles in good to excellent yields, exhibiting gram-scale ability and broad functional group tolerance utilizing easy to handle cheap and easily available reagents. The probable mechanisms for the formation of 1,2- and 1,3-dithioles from α-enolic dithioesters have been suggested.

ChemInform Abstract: One‐Pot Synthesis of 2,4,5‐Trisubstituted Imidazoles via [2 + 2 + 1] Cycloannulation of 1,3‐Bishet(aryl)‐monothio‐1,3‐diketones, α‐Substituted Methylamines and Sodium Nitrite Through α‐Nitrosation of Enaminones.

An efficient one-pot synthesis of a series of diversely functionalized trisubstituted 4(5)het(aroyl)-2,5(4)-het(aryl)/alkylimidazoles from readily available 1,3-bishet(aryl)monothio-1,3-diketones has been reported. This novel sequential one-pot, three step protocol, wherein three new carbon nitrogen bonds are formed in contiguous fashion, involves in situ generation of enaminones by reaction of monothio-1,3-diketones with α-substituted methylamines, followed by their α-nitrosation with sodium nitrite and subsequent base mediated intramolecular heterocyclization of the resulting α-hydroxyiminoimines to trisubstituted imidazoles in high yields under mild conditions. These newly prepared 4(5)-het(aroyl)-5(4)-het(aryl)/alkylimidazoles are shown to exist as tautomeric mixture, however, their subsequent alkylation with methyl iodide in the presence of potassium carbonate affords 1-N-methy-2,5-bishet(aryl)-4-het(aroyl)imidazoles in highly regioselective fashion in most of the cases. Synthesis of few 4(5)-(2-hydr...

Principled animation design improves comprehension of complex dynamics

Learners can have difficulty in decomposing conventionally designed animations to obtain raw material suitable for building high quality mental models. A composition approach to designing animations based on the Animation Processing Model was developed as a principled alternative to prevailing approaches. Outcomes from studying novel and conventional animation designs (independent variable) were compared with respect to mental model quality, knowledge of local kinematics, and capacity to transfer (dependent variables). Study of a compositional animation that presented material in a contiguous fashion resulted in higher quality mental models of a piano mechanism than non-contiguous or control (conventional) versions but no significant differences regarding local kinematics or transfer. Eye fixation data indicated that the compositional animation led to superior mental models because it particularly fostered relational processing. Implications for future research and the design of educational animations are discussed.

Abstract 1705: CCK2R marks a gastrin-responsive stem cell that gives rise to Barrett's esophagus

Abstract The incidence of esophageal adenocarcinoma (EAC) has markedly increased in the United States over the last few decades. Barrett's esophagus (BE) is the most significant known risk factor for this malignancy. Barrett's metaplasia, a condition of esophagus characterized by a columnar-cell metaplasia that replaces the native squamous-cell epithelium is considered to be a complication of gastroesophageal reflux disease (GERD), another risk factor for EAC. The paradigm is that BE arises from an adaptation to the harsh intra-esophageal environment of chronic GERD, and predisposes to EAC. Other established risk factors for EAC include obesity, smoking, poor diet. Moreover, while BE patients often undergo periodic endoscopic examinations, screening for dysplasia has not been shown to decrease mortality and remains controversial. Thus, a better understanding of the risk factors for BE progression is needed. The precise role of CCK2R in the gastric cardia and Barrett's esophagus has not been defined. CCK2R is upregulated in the esophagus in human BE and EAC, and real-time PCR of BE tissues indicated that the level of expression was 2x higher than that in esophageal tissues from normal control patients. CCK2R is upregulated in the gastric cardia of mice with Barrett's metaplasia, and this effect is enhanced with administration of bile acids, a key component of the refluxate. In this study we used the L2-IL-1β model to determine whether CCK2R-expressing cells can give rise to BE, and whether inhibition of CCK2R could ameliorate the BE phenotype in our mouse model. In order to understand the role of CCK2R-expressing cells in normal cardia, we performed lineage tracing studies in CCK2R-CreERT mice. We generated CCK2R-CreERT/TdTomato mice and induced them with tamoxifen at 6 weeks of age. Single Tomato-red positive cells became visible at the base of the cardia at 24 hours after induction. By days 2, 3, and 5 these Tomato-red cells expanded and moved upward in the cardia gland in contiguous fashion until almost all the cells in the gland were labeled. Tomato-red cells persisted for as long as one year in the cardia. Thus, CCK2R labels a progenitor cell in the normal gastric cardia whose progeny populate the gland and persist for at least one year, suggesting the ability to self-renew and consistent with a cardia stem cell. Since CCK2R marks a proliferating progenitor cell in the cardia, we verified whether CCK2R also has functional importance in BE progression. We hypothesized that overexpression of gastrin, the ligand for CCK2R, could accelerate BE in L2-IL-1β mice. INS-GAS mice, which overexpress amidated gastrin under the transcriptional control of the insulin promoter, were crossed with L2-IL-1β mice. L2-IL-1β/INS-GAS mice treated with bile acids had significantly increased areas of BE involvement compared to L2-IL-1β or INS-GAS controls. No areas of BE were seen in wild type or INS-GAS mice treated with bile acids until the age of 12 months. Citation Format: Aleksandra M. Urbanska, Yoomi Lee, Yoku Hayakawa, Julian A. Abrams, Michael Quante, Timothy C. Wang. CCK2R marks a gastrin-responsive stem cell that gives rise to Barrett's esophagus. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1705.

One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles via [2 + 2 + 1] Cycloannulation of 1,3-Bishet(aryl)-monothio-1,3-diketones, α-Substituted Methylamines and Sodium Nitrite through α-Nitrosation of Enaminones

An efficient one-pot synthesis of a series of diversely functionalized trisubstituted 4(5)het(aroyl)-2,5(4)-het(aryl)/alkylimidazoles from readily available 1,3-bishet(aryl)monothio-1,3-diketones has been reported. This novel sequential one-pot, three step protocol, wherein three new carbon nitrogen bonds are formed in contiguous fashion, involves in situ generation of enaminones by reaction of monothio-1,3-diketones with α-substituted methylamines, followed by their α-nitrosation with sodium nitrite and subsequent base mediated intramolecular heterocyclization of the resulting α-hydroxyiminoimines to trisubstituted imidazoles in high yields under mild conditions. These newly prepared 4(5)-het(aroyl)-5(4)-het(aryl)/alkylimidazoles are shown to exist as tautomeric mixture, however, their subsequent alkylation with methyl iodide in the presence of potassium carbonate affords 1-N-methy-2,5-bishet(aryl)-4-het(aroyl)imidazoles in highly regioselective fashion in most of the cases. Synthesis of few 4(5)-(2-hydroxyphenyl)-2,5(4)-substituted imidazoles, which are known to be good coordinating ligands, has also been reported. A probable mechanism for the formation of these imidazoles from hydroxyiminoimine intermediates has also been suggested.

Towards Automatic Web Data Scraper and Aligner (WDSA).

Web is very immense and fast emerging source of information. Web browsers along with search engines have come forward as famous tools for retrieving and accessing the information present on web. Enormous growth of web made the data extraction from web harder than ever. This paper presents the Automatic Web Data Scraper and Aligner (WDSA). Automatic WDSA extracts the interested web data present in dynamically generated web page received from search engine when user gives a query. Automatic web data scraping is necessary because human being can identify the interested query relevant contents from query result web page, however it is tricky for computer applications. Extracted web data can be further transferred into a format suitable for use in applications like comparison shopping, data integrations, value added services etc. WDSA does this by aligning the extracted web data pairwise as well as holistically in table. The novel thing about Automatic WDSA is that Data Scraper and Aligner uses new approach which combines similarity of both tag and value, for extraction and alignment process. Also Data Scraper handles the data which is present in non contiguous fashion due to presence of auxiliary information like advertisement banners, navigational links, pop ups etc. Experimental results show that Automatic WDSA achieves high precision and recall. Further Automatic WDSA is compared with existing most widely used famous tools like Helium scraper, Outwit Hub, Screen Scraper etc. During comparison we observed that Manual labeling or extraction patterns of desired data is to be specified for working of existing tools while Automatic WDSA does not require any user involvement which made it fully automatic.

Temporally Contiguous Pencast Instruction Promotes Meaningful Learning for Dental and Dental Hygiene Students in Physiology

Smartpens allow for the creation of computerized "pencasts" that combine voice narration with handwritten notes and illustrations. The purpose of this study was to test the effects of voluntary participation in extracurricular instruction with a pencast on student learning. Dental and dental hygiene students were given instruction in a complex physiological topic using lecture and static slides. An Internet link to a pencast that covered the complex topic in a more temporally contiguous fashion was also provided for voluntary review. The students were given a multiple-choice exam that consisted of retention and transfer test questions. Sixty-nine percent of the students who did not watch the pencast and 89 percent of the students who watched the pencast answered the retention test question correctly (p=0.08). Fifty-four percent of the students who did not watch the pencast and 90 percent of the students who watched the pencast answered the transfer test question correctly (p=0.005). This finding indicates that students who watched the pencast performed better on a transfer test, a measurement of meaningful learning, than students who received only the narrated instruction with static images. This supports the hypothesis that temporally contiguous instruction promotes more meaningful learning than lecture accompanied only by static slide images.

A practical grading system of ultrasonographic visibility for intracerebral lesions

Intraoperative ultrasound for intracranial neurosurgery was largely abandoned in the 1980s due to poor image resolution. Despite many technological advances in ultrasound since then, the use of this imaging modality in contemporary practice remains limited. Our aim was to evaluate the utility of modern intraoperative ultrasound in the resection of a wide variety of intracranial pathologies. A total of 105 patients who underwent intracranial lesion resection in a contiguous fashion were prospectively included in the study. Ultrasound images acquired intraoperatively were used to stratify lesions into one of four grades (grades 0-3) on the basis of their ultrasonic echogenicity and border visibility. Forty-two out of 105 lesions (40 %) were clearly identifiable and had a clear border with normal tissue (grade 3). Fifty-five of 105 lesions (52 %) were clearly identifiable but had no clear border with normal tissue (grade 2). Eight of 105 lesions (8 %) were difficult to identify and had no clear border with normal tissue (grade 1). None (0 %) of the lesions could not be identified (grade 0). High-grade gliomas, cerebral metastases, meningiomas, ependymomas, and haemangioblastomas all demonstrated a median ultrasonic visibility grade of 2 or greater. Low-grade astrocytomas and oligodendrogliomas demonstrated a median ultrasonic visibility grade of 2 or less. Intraoperative ultrasound can be of tremendous benefit in allowing the surgeon to appraise the location, extent, and local environment of their target lesion, as well as to reduce the risk of preventable complications. We believe that our grading system will provide a useful adjunct to the neurosurgeon when deciding for which lesions intraoperative ultrasound would be useful.

Patterns of Local Extension and Regional Spread in Early Stage Nasal NK/T-cell Lymphoma Based on Magnetic Resonance Imaging

Patterns of Local Extension and Regional Spread in Early Stage Nasal NK/T-cell Lymphoma Based on Magnetic Resonance Imaging

Hidden dynamic allostery in a PDZ domain

Structure-function relationships in proteins are predicated on the spatial proximity of noncovalently interacting groups of atoms. Thus, structural elements located away from a protein's active site are typically presumed to serve a stabilizing or scaffolding role for the larger structure. Here we report a functional role for a distal structural element in a PDZ domain, even though it is not required to maintain PDZ structure. The third PDZ domain from PSD-95/SAP90 (PDZ3) has an unusual additional third alpha helix (alpha3) that packs in contiguous fashion against the globular domain. Although alpha3 lies outside the active site and does not make direct contact with C-terminal peptide ligand, removal of alpha3 reduces ligand affinity by 21-fold. Further investigation revealed that the difference in binding free energies between the full-length and truncated constructs is predominantly entropic in nature and that without alpha3, picosecond-nanosecond side-chain dynamics are enhanced throughout the domain, as determined by (2)H methyl NMR relaxation. Thus, the distal modulation of binding function appears to occur via a delocalized conformational entropy mechanism. Without removal of alpha3 and characterization of side-chain dynamics, this dynamic allostery would have gone unnoticed. Moreover, what appeared at first to be an artificial modification of PDZ3 has been corroborated by experimentally verified phosphorylation of alpha3, revealing a tangible biological mechanism for this novel regulatory scheme. This hidden dynamic allostery raises the possibility of as-yet unidentified or untapped allosteric regulation in this PDZ domain and is a very clear example of function arising from dynamics rather than from structure.

Visually-Guided Balloon Catheter Ablation of Atrial Fibrillation

Electric isolation of the pulmonary veins (PVs) can successfully treat patients with paroxysmal atrial fibrillation. However, it remains technically challenging to identify the left atrial-PV junction and sequentially position the ablation catheter in a point-by-point contiguous fashion to isolate the PVs. In this study, a novel endoscopic ablation system was used to directly visualize and ablate tissue at the left atrial-PV junction with laser energy. This study consisted of 2 phases: a short-term (n=9) and long-term (n=11) canine experimental validation phase and a multicenter clinical feasibility phase (n=30 paroxysmal atrial fibrillation patients). After transseptal puncture, the balloon-based endoscopic ablation system was advanced to each PV ostium, and arcs of laser energy (90 degrees to 360 degrees ) were projected onto the target left atrial-PV junction. Electric PV isolation was defined with a circular multielectrode catheter. In the short-term preclinical experimental phase, 15 of 17 targeted PVs (88%) were successfully isolated. Pathological examination revealed well-demarcated circumferential lesions with minimal endothelial disruption. In the long-term experiments, 9 of 10 targeted veins (90%) remained persistently isolated (at 4 to 8 weeks). In the clinical phase, 105 of 116 PVs (91%) were successfully isolated. After a single procedure, the 12-month drug-free rate of freedom from atrial fibrillation was 60% (18 of 30 patients). There were no significant PV stenoses, but adverse events included 1 episode of cardiac tamponade, 1 stroke without residual defect, and 1 asymptomatic phrenic nerve palsy. This study establishes the feasibility of a novel paradigm for AF ablation: direct visualization to guide catheter ablation of the left atrial-PV junction.

Angiomatosis: A Case With Metaplastic Ossification

Angiomatosis is defined as a hemangioma that affects a large segment of the body in a contiguous fashion, either by vertical extension to involve multiple tissue planes (eg, skin, subcutis, muscle, bone) or by crossing muscle compartments to involve similar tissue types (eg, multiple muscles). Such lesions usually present in the first 2 decades of life and have a highly characteristic but not totally specific histological pattern. Histology usually shows a haphazard mixture of small and medium-sized vessels, fat, connective tissue, and lymphatics. Large amounts of mature fat frequently accompany the vascular elements, suggesting that the lesion may possibly be a more generalized mesenchymal proliferation rather than an exclusively vascular lesion. Here we present what we believe to be the first case of angiomatosis showing osseous metaplasia.

Lateral Lymph Node Metastasis in Papillary Thyroid Carcinoma: Results of Therapeutic Lymph Node Dissection

Cervical lymph node metastases are quite common in papillary thyroid cancer (PTC) and they usually spread in a contiguous fashion. However, "skip metastasis," defined as lateral lymph node metastasis without central lymph node metastasis, also occurs in patients with PTC. There is little information regarding skip metastasis in papillary thyroid microcarcinoma (PTMC). The goal of this study was to determine the prevalence and associated clinical and imaging features of skip metastasis in PTMC. We performed a retrospective study of 245 patients with PTMC who underwent either thyroidectomy and central lymph node dissection or thyroidectomy, central lymph node dissection, and lateral lymph node dissection if preoperative ultrasonography or computed tomography suggested lateral node metastasis. Clinicopathologic results were reviewed, and the patterns of cervical lymph node metastasis were analyzed. Cervical lymph node metastases were present in 26.5% of cases. The frequency of lymph node metastases was 21.8% in the group that only had thyroidectomy and central lymph node dissection and 51.3% in the group that had thyroidectomy, central lymph node dissection, and lateral lymph node dissection. Younger age, larger tumor size, multiplicity, bilaterality, encapsulation, extrathyroid extension, and lymphatic invasion were associated with metastasis to nodes in the central or lateral compartment. Lateral lymph node dissection was performed in 15.9% of patients. Skip metastasis was observed in 7.7% of the cases in which combined central and lateral node dissection was performed. No features of the primary thyroid tumor could be associated with the development of skip metastasis. Skip metastases occur in a minority of patients with PTMC. We recommend, therefore, that preoperative studies in patients suspected of having PTMC focus not only on nodes in the central compartment but also lateral cervical nodes since the information obtained would guide the extent of surgery.