3-dimensional Computed Tomography Reconstruction Research Articles

The role of 3-dimensional printed models in the management of the distal radius fractures.

This study aimed to compare inter- and intra-observer agreement between radiographs with 2-dimensional and 3-dimensional computed tomography scans with and without 3-dimensional printed models in the evaluation of the distal radius fracture of Association for Osteo synth esis/ Ortho paedi c Trauma Association type C classification. Fifteen consecutive cases with X-Rays, 2-dimensional and 3-dimensional computed tomography reconstructions views, and 3-dimensional printed models were selected. Three-dimensional printed models of the distal radius fractures were created using 2-dimensional computed tomography scan files in Digital Imaging and Communication in Medicine format, processed with the 3-dimensional Slicer software, and segmented, creating a 3-dimensional printed model in Standard Triangle Language format. Threedimensional models were printed using fused deposition modeling (FDM) type 3D printer Zortrax M200Plus using polylactic acid material on a scale of 1 : 1. Twenty observers were invited into the study. Intra- and inter-observer reliability was analyzed using Fleiss' kappa statistics. Overall kappa values for both groups in interobserver agreement range from 0.113 to 0.283 and in intra-observer agreement from 0.25 to 0.545. Generally, inter-observer agreement increased with additional 3-dimensional printed models from slight to fair, and intra-observer agreement increased from fair to moderate. Surgeons' opinions about 3-dimensional printed models with Likert scale-type questions show positive overall results ranging from 8.3± 2.1 to 8.6 ± 1.4. This study has shown that the inter- and intra-observer agreement with the addition of a 3-dimensional printed model for the evaluation of the distal radius fractures of Association For Osteo synth esis/ Ortho pedic Trauma Association C type for classification, fractures morphology, and preoperative planning tends to increase; however, improvements for an inter-observer agreement remain fair. Level III Diagnostic Study.

A 3-Dimensional Measurements of Bone and Airway Variables After Le Fort I Distraction Osteogenesis in Patients With Cleft Lip and/or Palate-Induced Midface Hypoplasia: A Retrospective Study.

The authors retrospectively analyzed the effects of Le Fort I advancement with distraction osteogenesis on skeletal and airway variables in patients with midfacial hypoplasia induced by cleft lip and/or palate using 3-dimensional computed tomography reconstructions. The authors enrolled 23 subjects with moderate-to-severe midface hypoplasia induced by cleft lip and palate who were treated with Le Fort I distraction osteogenesis (mean age, 19.22±3.48y; male/female ratio, 20/3); computed tomography images (1 before distraction and another at completion of distraction) were acquired. A 3-dimensional craniometric findings and airway volumes for the nasal cavity, nasopharynx, velopharynx, and upper and lower oropharynx were compared before and after distraction. The relationships between craniofacial morphology and changes in airway volume were also assessed ( P <0.05 was considered significant). Significant increases were observed in airway volumes for the nasal cavity (13.85%), nasopharynx (50.82%), velopharynx (29.57%), and upper oropharynx (36.92%) ( P =0.007, P <0.001, P =0.023, and P <0.001, respectively), whereas no significant changes were observed for the lower oropharynx ( P =0.117). Maxillary horizontal advancement was positively correlated with the airway volumes of the nasopharynx and upper oropharynx after distraction osteogenesis ( rs =+0.451, P =0.031; rs =+0.548, P =0.007); however, no significant correlations were observed for the nasal cavity and velopharynx. The authors' finding indicate that despite rotation of the mandible along with the maxilla, this change does not impact airway volume at the mandibular level. Le Fort I distraction osteogenesis can be feasible for patients with cleft lip and palate-induced midface hypoplasia, with satisfactory appearance and occlusion. Long-term detailed follow-up of the patients postdistraction osteogenesis is warranted.

Identifying a Novel Critical Access Difficulty Factor in Percutaneous Radiofrequency Rhizotomy for Trigeminal Neuralgia: Pterygoid Process Ridge.

Percutaneous stereotactic radiofrequency rhizotomy (PSR) is an ablative procedure for trigeminal neuralgia (TN). The anatomic structures that pass through, or around, the foramen ovale (FO) play vital roles in the success rate of PSR. The presence of a variant pterygoid process ridge (PPR) obscuring the FO renders the cannulation procedure difficult but had not been described in the literature before. To identify the variations of the PPR to assess cannulation difficulty. Fifty seven FOs of 57 patients with TN (TN group) and 438 FOs of 232 patients without TN (non-TN group) were analyzed using 3-dimensional computed tomography reconstruction images of cranial bases. Three-dimensional printer models were also used for TN patients with PPR-obscured FOs. Measurements were obtained for shape, size, and morphometric variability effect on cannulation. We identified 5 PPR-obscured FOs (8.8%) in the TN group and 32 FOs (7.3%) in the non-TN group. In the TN group, the transverse diameter obstruction ranged from 19.2% to 39.7% in 4 patients, and 1 case was 100%. Of particular note, approximately one-quarter to one-third of FO preset targets were affected by PPR. A PPR-obscured FO represents a new confounding factor in the conduct of PSR. Confirming the PPR-obscured FO is a critical step in improving the effectiveness of puncture target presetting, ie, evaluating the target with actual FO data is an improvement over the use of surgical view FO data. Discernment of the PPR can improve the success rate of difficult-to-access FO punctures, thereby rendering PSR more effective.

Intraoperative Tumor Localization of Early Gastric Cancers.

Recently, endoscopic screening systems have enabled the diagnosis of gastric cancer in the early stages. Early gastric cancer (EGC) is typically characterized by a shallow invasion depth and small size, which can hinder localization of EGC tumors during laparoscopic surgery. Here, we review nine recently reported tumor localization methods for the laparoscopic resection of EGCs. Preoperative dye or blood tattooing has the disadvantage of spreading. Preoperative 3-dimensional computed tomography reconstruction is not performed in real time during laparoscopic gastrectomy. Thus, they are considered to have a low accuracy. Intraoperative portable abdominal radiography and intraoperative laparoscopic ultrasonography methods can provide real-time feedback, but these methods require expertise, and it can be difficult to define the clips in some gastric regions. Despite a few limitations, intraoperative gastrofibroscopy provides real-time feedback with high accuracy. The detection system using an endoscopic magnetic marking clip, fluorescent clip, and radio-frequency identification detection system clip is considered highly accurate and provides real-time feedback; we expect a commercial version of this setup to be available in the near future. However, there is not yet an easy method for accurate real-time detection. We hope that improved devices will soon be developed and used in clinical settings.

Treatment of cervical spondylotic radiculopathy with posterior percutaneous endoscopic cervical discectomy: Short-term outcomes of 24 cases.

To determine the short-term clinical outcomes of single-segment cervical spondylotic radiculopathy treated with posterior percutaneous endoscopic cervical discectomy (PPECD).Data of a total of 24 patients who underwent PPECD and local anesthesia for single-level segmental cervical spondylotic radiculopathy between March 2016 and December 2017 were reviewed. The Japanese Orthopaedic Association, visual analog scale (VAS), and neck disability index scores at preoperative 1 day, postoperative 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year were recorded. The modified MacNab criteria at the last follow-up were re-recorded for the evaluation of clinical effectiveness.All operations were successfully completed under endoscopic guidance. No patient showed spinal cord, nerve root, vascular injuries, dural tears or other complications. The postoperative VAS scores of the arm and neck were significantly reduced compared with the preoperative VAS scores (P < .05), while postoperative the Japanese Orthopaedic Association scores were significantly increased (P < .05). The postoperative neck disability index scores were significantly reduced compared with preoperative scores (P < .05). The modified MacNab criteria at the last follow-up showed 16 excellent cases, 8 good cases, 0 fine cases, and 0 poor cases. Postoperative magnetic resonance imaging and cervical 3-dimensional computed tomography reconstruction showed that the intervertebral disc was adequately resected and the nerve root was not under compression.PPECD is safe and effective for the treatment of single-segment cervical spondylotic radiculopathy.

Fracture-Associated Bruising and Soft Tissue Swelling in Young Children With Skull Fractures: How Sensitive Are They to Fracture Presence?

The aim of this study was to determine how reliable scalp bruising and soft tissue swelling/cephalohematomas (STS) are for underlying young child skull fractures. This was a retrospective clinical and imaging review from 2011 to 2012 of children younger than 4 years with skull fractures from 2 tertiary care hospitals. Imaging was reread by 3 pediatric radiologists. Descriptive statistics were utilized. The retrospective review had institutional review board approval. We identified 218 subjects for review: 210 unintentional and 8 abusive. One hundred forty-three had available 3-dimensional computed tomography reconstructions: 136 unintentional and 7 abused. Two-thirds were younger than 1 year. Twelve subjects had visible scalp bruising, but 73% had clinically and 93% radiologically apparent fracture-associated STS. There was no difference in clinical STS with simple (79%) versus complex (68%) fractures. Nor was there difference in subjects with fractures from minor (77%) versus major (70%) trauma. Unintentionally injured infants did not differ from abused for detectable STS (74% vs 50%). Parietal and frontal bones most frequently sustained fractures and most consistently had associated STS. Clinically apparent STS is present in approximately three-fourths of children with skull fractures. It may not be important to consistently identify skull fractures in unintentionally injured children. Point-of-care ultrasound may be adequate. For abuse concerns, it is important to identify skull fractures as evidence of cranial impacts and intracranial hemorrhages. The most sensitive, widely available imaging technique, cranial computed tomography scan with 3-dimensional skull reconstruction, should be utilized. Scalp bruising is present in a minority of young children with skull fractures. Its absence does not exclude cranial impact injury.

Incidence and characteristics of left atrial appendage stumps after device-enabled epicardial closure.

High success rates for left atrial appendage (LAA) exclusion with the AtriClip (Atricure, USA) device have been reported in the literature. This study evaluated the presence and characteristics of residual LAA stumps after AtriClip LAA exclusion using postoperative short- and long-term computed tomography angiography (CTA). In this retrospective analysis, 43 of 291 consecutive patients undergoing cardiac surgery with concomitant LAA occlusion using the AtriClip device were identified with available postoperative short- and long-term follow-up by CTA. LAA patency and the absence or the size of a present residual LAA stump were assessed on 2-dimensional multiplanar reconstructions, on maximum intensity projection images and on volume-rendered 3-dimensional computed tomography reconstructions. Based on current recommendations, the threshold for a significant LAA stump length was defined <10 mm. The LAA was successfully occluded in all 43 patients (100%) as confirmed by intraoperative transoesophageal echocardiography and CTA imaging with a mean follow-up duration of 7.1 ± 0.8 years post-implant. The absence of blood flow in the excluded LAA was confirmed in all cases. In 31 of 43 patients (72%), no residual stump (0 mm) was observed creating a smooth endocardial surface, CTA revealed residual LAA stumps in 11/43 patients (26%) with a length <10 mm and a significant residual stump with a depth of >10 mm (12 mm) in 1 patient (2%). The mean length, width and depth of the residual stumps were 5.8 ± 2.1, 4.4 ± 1.2 and 7.3 ± 2.3 mm, respectively. This study investigated the incidence of residual stump formation (>10 mm) after LAA closure with the AtriClip device based on CTA imaging data obtained during short- and long-term follow-up. While no LAA stump was detectable in the majority of patients, a non-significant LAA stump (<10 mm) was present in 26% of cases, indicating a favourable LAA occlusion profile for the AtriClip device. However, although a LAA stump length <10 mm is currently considered clinically safe, this definition needs further attention in future studies with regards to its potential clinical implications.

Aortic Anatomic Severity Grade Correlates with Midterm Mortality in Patients Undergoing Abdominal Aortic Aneurysm Repair.

Anatomic severity grade (ASG) can be used to assess abdominal aortic aneurysm (AAA) anatomic complexity. High ASG is associated with complications following endovascular repair of AAAs and we have demonstrated that ASG correlates with resource utilization. The hypothesis of this study is that ASG is directly related to midterm mortality in patients undergoing AAA repair. Patients who underwent infrarenal AAA repairs between July 2007 and August 2014 were retrospectively reviewed and ASG scores were calculated using 3-dimensional computed tomography reconstructions. Perioperative mortalities (≤30 days) were excluded. The ASG value of 15 was chosen based on previous receiver-operator curve analysis, which showed that an ASG of 15 was predictive of postoperative complications and resource utilization. The 5-year survivors and mortalities were compared utilizing comorbidities, pharmacologic variables, and anatomic variables at or above the defined threshold. A total of 402 patients (80% male and 96% Caucasian) with complete anatomic and survival data were included in the analysis. Mean ASG and age at the time of repair were 16 ± 0.15 and 73 ± 0.43 years old, respectively. The 5-year mortality was significantly associated with ASG >15 (hazard ratio [HR]: 1.504, confidence interval [CI]: 1.077-2.100, P < .017), hyperlipidemia (HR: 1.987, CI: 1.341-2.946, P < .001), coronary artery disease (HR: 1.432, CI: 1.037-1.978, P < .029), and chronic obstructive pulmonary disease (HR: 1.412, CI: 1.027-1.943, P < .034). Kaplan-Meier analysis demonstrated improved survival in the low score ASG ≤15 group at 1, 3, and 5 years (96% vs 93%, 81% vs 69%, and 53% vs 41%; P = .0182; Figure 1). Increasing aortic anatomic complexity as characterized by ASG >15 is an independent predictor of midterm mortality following elective infrarenal AAA repair. Therefore, it may be a useful tool for appropriate patient selection and risk stratification prior to elective infrarenal AAA repair.

Relationship of Intraoperative Anatomical Landmarks, the Scapular Plane and the Perpendicular Plane with Glenoid for Central Guide Insertion during Shoulder Arthroplasty.

BackgroundThis study was undertaken to evaluate the positional relationship between planes of the glenoid component (the scapular plane and the perpendicular plane to the glenoid) and its surrounding structures.MethodsComputed tomography (CT) images of both shoulders of 100 patients were evaluated using the 3-dimensional CT reconstruction program (Aquarius®; TeraRecon). We determined the most lateral scapular bony structure of the scapular plane and measured the shortest distance between the anterolateral corner of the acromion and the scapular plane. The distance between the scapular plane and the midpoint of the line connecting the posterolateral corner of acromion and the anterior tip of the coracoid process (fulcrum axis) was also evaluated. The perpendicular plane was then adjusted to the glenoid and the same values were re-assessed.ResultsThe acromion was the most lateral scapular structure of scapular plane and perpendicular plane to the glenoid. The average distance from the anterolateral corner of the acromion to the scapular plane was 10.44 ± 5.11 mm, and to the plane perpendicular to the glenoid was 9.55 ± 5.13 mm. The midpoint of fulcrum axis was positioned towards the acromion and was measured at 3.90 ± 3.21 mm from the scapular plane and at 3.84 ± 3.17 mm from the perpendicular plane to the glenoid.ConclusionsOur data indicates that the relationship between the perpendicular plane to the glenoid plane and its surrounding structures is reliable and can be used as guidelines during glenoid component insertion (level of evidence: Level IV, case series, treatment study).

Morphologic variations of the scapula in 3-dimensions: a statistical shape model approach

Morphologic variations of the scapula and acromion have been found to be associated with shoulder pathology. This study used statistical shape modelling to quantify these variations in healthy shoulders. A statistical shape model of the scapula was created using 3-dimensional computed tomography reconstructions of 108 survey-confirmed nonpathologic shoulders of 54 patients. The mean shape and the 95% confidence interval were calculated and analyzed in the first 5 shape modes. The first 5 shape modes consisted of consecutively sized (72% of total variation), rotation of the coracoacromial complex (5%), acromial shape and slope (4%), shape of the scapular spine (2%), and acromial overhang (2%). In healthy shoulders, a certain variation in rotation of the coracoacromial complex and in acromial shape and slope was observed. These new parameters might be correlated with shoulder pathology such as glenohumeral osteoarthritis or rotator cuff tears.

Variability in the Contour of Cadaveric Anterior and Posterior Glenoids Based on Ipsilateral 3-Dimensional Computed Tomography Reconstructions: Implications for Clinical Estimation of Bone Loss

To compare differences in the contour of the anterior and posterior glenoid in 3-dimensional computed tomography reconstructions as a reason for variability in estimating glenoid bone loss. Three reviewers digitally placed 11points (1 at 6 o'clock, 5 from 3 to 6 o'clock, and 5 from 6 to 9 o'clock) along the inferior half of glenoid 3-dimensional computed tomography reconstructions of 32 cadaveric specimens. A best-fit circle for the whole glenoid was determined from all 11 points. The anterior 6 points determined an anterior-based circle, as for estimation of posterior bone loss. The posterior 6 points determined a posterior-based circle, as for estimation of anterior bone loss. The area and radii were determined for all circles. Individual intraclass correlations were used to evaluate reliability. Paired t-tests and Wilcoxon signed rank tests were used to compare areas and radii of the anterior and posterior circles relative to the best-fit glenoid circle. Significance was defined as P<.05. There was good-to-excellent inter-rater reliability for the overall best-fit circle (intraclass correlation coefficient [ICC]= 0.97 [95% confidence interval (CI), 0.95-0.99]), anterior circle (ICC= 0.82 [95% CI, 0.71-0.90]), and posterior circle (ICC= 0.78 [95% CI, 0.65-0.88]). The average area of the posterior-based circle was significantly greater than the area of the best-fit circle for the intact glenoid (111% [95% CI, 104.3%-117.7%]; P= .0016). The average radius of the posterior-based circle was significantly larger than the radius of the intact glenoid (105% [95% CI, 101.7%-108.3%]; P= .0042). There were no significant differences between the average area (96% [95% CI, 89.0%-103.0%]; P= .16) and average radius (97% [95% CI, 93.5%-100.5%]; P= .19) for the anterior-based circle relative to the actual whole glenoid. Estimation of anterior glenoid bone loss based on the normal posterior glenoid rim may overestimate glenoid bone loss because of differences in the contour of the anterior and posterior glenoid, whereas estimations of posterior glenoid bone loss based on the anterior rim did not differ significantly from the intact glenoid. A circle based on the remaining intact portion of the injured glenoid may lead to an inaccurate estimate of glenoid bone loss.

Machine-learning phenotypic classification of bicuspid aortopathy

BackgroundBicuspid aortic valves (BAV) are associated with incompletely characterized aortopathy. Our objectives were to identify distinct patterns of aortopathy using machine-learning methods and characterize their association with valve morphology and patient characteristics. MethodsWe analyzed preoperative 3-dimensional computed tomography reconstructions for 656 patients with BAV undergoing ascending aorta surgery between January 2002 and January 2014. Unsupervised partitioning around medoids was used to cluster aortic dimensions. Group differences were identified using polytomous random forest analysis. ResultsThree distinct aneurysm phenotypes were identified: root (n = 83; 13%), with predominant dilatation at sinuses of Valsalva; ascending (n = 364; 55%), with supracoronary enlargement rarely extending past the brachiocephalic artery; and arch (n = 209; 32%), with aortic arch dilatation. The arch phenotype had the greatest association with right–noncoronary cusp fusion: 29%, versus 13% for ascending and 15% for root phenotypes (P < .0001). Severe valve regurgitation was most prevalent in root phenotype (57%), followed by ascending (34%) and arch phenotypes (25%; P < .0001). Aortic stenosis was most prevalent in arch phenotype (62%), followed by ascending (50%) and root phenotypes (28%; P < .0001). Patient age increased as the extent of aneurysm became more distal (root, 49 years; ascending, 53 years; arch, 57 years; P < .0001), and root phenotype was associated with greater male predominance compared with ascending and arch phenotypes (94%, 76%, and 70%, respectively; P < .0001). Phenotypes were visually recognizable with 94% accuracy. ConclusionsThree distinct phenotypes of bicuspid valve–associated aortopathy were identified using machine-learning methodology. Patient characteristics and valvular dysfunction vary by phenotype, suggesting that the location of aortic pathology may be related to the underlying pathophysiology of this disease.

Intraoperative Computed Tomography Navigation During Thoracoscopic Segmentectomy for Small-sized Lung Tumors

Performance of thoracoscopic pulmonary segmentectomy for primary lung cancer or pulmonary metastases has recently increased. In patients with emphysema, identification of the intersegmental line is often difficult. For nonpalpable lesions, securing a sufficient surgical margin is more likely to be uncertain. The purpose of this study was to evaluate the efficacy of intraoperative computed tomography (CT) scan during video-assisted thoracoscopic surgery (VATS) pulmonary segmentectomy. This study included 12 patients who underwent intraoperative CT-assisted VATS segmentectomy between January 2015 and August 2016. After dividing the corresponding vessels and bronchi, the intersegmental line was marked by clipping, and intraoperative CT scan was performed under bilateral lung ventilation. The intraoperative CT or 3-dimensional CT reconstruction images were used by the surgeons to confirm the correct anatomical segmental border and to secure a sufficient resection margin. In all patients, the location of the lesions to be resected, the intersegmental border, and the surgical margins could be confirmed while performing VATS segmentectomy. Complete resection was achieved in all patients. Although the pathologic margins tended to be shorter than the surgical margins on intraoperative CT images, there was a strong correlation between these 2 variables (r = 0.963, P < 0.0001). Intraoperative CT scan during VATS segmentectomy was useful for identifying the location of nonpalpable lesions, confirming anatomical intersegmental borders and securing the resection margins. Intraoperative CT navigation could enable a more definitive VATS segmentectomy for nonpalpable lesions.

The “absent” left atrial appendage…

Isolated congenital absence of the left atrial appendage (LAA) is a rare condition. The diagnosis results from a review of the past medical and surgical history in addition to the use of multimodality imaging, as several other conditions (thrombotic occlusion, surgical or percutaneous exclusion, variations in morphology and relative position of anatomic structures) may present with a similar finding. A 62-year-old woman with a history of obesity, hypertension, and symptomatic persistent atrial fibrillation for which she was treated with chronic oral anticoagulation elected to undergo catheter ablation. A preprocedural cardiac computed tomography showed a single left-sided and 2 right-sided pulmonary veins, no intracardiac thrombus, and no evidence of an LAA. Given no history of a prior cardiac procedure or surgery, absence of the LAA was presumed to be congenital. Transesophageal echocardiography and 3-dimensional computed tomography reconstruction of the left atrium in an electroanatomic mapping system (CARTO, Biosense Webster, Diamond Bar, CA) similarly demonstrated no LAA (Figure 1A and B). Her anatomy created no challenges for cryoballoon pulmonary vein isolation, which was successfully performed without complication. The appendage, unlike the pulmonary veins and posterior left atrium, derives from the primitive atrium, a structure that develops into a basal mesodermal layer, endocardial trabeculae, and pectinate muscles. The LAA accounts for ∼90% of intracardiac thrombi associated with nonvalvular atrial fibrillation.1Naksuk N. Padmanabhan D. Yogeswaran V. Asirvatham S.J. Left atrial appendage: embryology, anatomy, physiology, arrhythmia and therapeutic intervention.JACC Clin Electrophysiol. 2016; 2: 403-412Crossref PubMed Scopus (39) Google Scholar Given data demonstrating that occlusion of the LAA serves as a safe, alternative means of reduction of cardioembolic stroke risk when compared to warfarin,2Holmes Jr., D.R. Kar S. Price M.J. Whisenant B. Sievert H. Doshi S.K. Huber K. Reddy V.Y. Prospective randomized evaluation of the Watchman Left Atrial Appendage Closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial.J Am Coll Cardiol. 2014; 64: 1-12Crossref PubMed Scopus (1080) Google Scholar, 3Wiebe J. Franke J. Lehn K. Hofmann I. Vaskelyte L. Bertog S. Sievert H. Percutaneous left atrial appendage closure with the Watchman device.JACC Cardiovasc Interv. 2015; 8: 1915-1921Crossref PubMed Scopus (34) Google Scholar it is plausible that congenital absence of the LAA conveys a similar naturally occurring risk reduction. However, it is unlikely that this will ever be meaningfully examined, given the rarity of the condition, with only a few reports of isolated congenital absence of the LAA noted in literature.4Saleh M. Balakrishnan R. Castillo Kontak L. Benenstein R. Chinitz L.A. Donnino R. Saric M. Congenital absence of the left atrial appendage visualized by 3D echocardiography in two adult patients.Echocardiography. 2015; 32: 1206-1210Crossref PubMed Scopus (10) Google Scholar, 5Collier P. Cavalcante J.L. Phelan D. Thavendiranathan P. Dahiya A. Grant A. Kwon D. Thamilarasan M. Congenital absence of the left atrial appendage.Circ Cardiovasc Imaging. 2012; 5: 549-550Crossref PubMed Scopus (19) Google ScholarKey Teaching Points•Isolated congenital absence of the left atrial appendage is a rare condition.•The diagnosis is best made after a comprehensive review of a patient’s past medical and surgical history in addition to use of multimodality imaging, as other conditions (thrombotic occlusion, surgical or percutaneous exclusion, variations in morphology and relative position of anatomic structures) may present with a similar finding.•It is plausible, although not known, that among patients with nonvalvular atrial fibrillation those with isolated congenital absence of the left atrial appendage may have a naturally occurring decreased risk for cardioembolic stroke. •Isolated congenital absence of the left atrial appendage is a rare condition.•The diagnosis is best made after a comprehensive review of a patient’s past medical and surgical history in addition to use of multimodality imaging, as other conditions (thrombotic occlusion, surgical or percutaneous exclusion, variations in morphology and relative position of anatomic structures) may present with a similar finding.•It is plausible, although not known, that among patients with nonvalvular atrial fibrillation those with isolated congenital absence of the left atrial appendage may have a naturally occurring decreased risk for cardioembolic stroke.

Guidelines for humeral subluxation cutoff values: a comparative study between conventional, reoriented, and three-dimensional computed tomography scans of healthy shoulders

The humeral subluxation index (HSI) is frequently assessed on computed tomography (CT) scans in conditions of the shoulder characterized by humeral displacement. An arbitrarily set HSI cutoff value of 45% for anterior subluxation and 55% for posterior subluxation has been widely accepted. We studied whether mean values and thresholds of humeral subluxation, in relation to the glenoid and scapula, were influenced by different imaging modalities. The HSIs referenced to the scapula (SHSI) and glenoid (GHSI) were compared between conventional CT scans, CT scans reoriented into the corresponding reference plane (ie, scapular plane for the SHSI and glenoid center plane for the GHSI), and 3-dimensional (3D) CT reconstructions of 120 healthy shoulders. The 95% normal range determined the cutoff values of humeral subluxation. The SHSI thresholds for conventional, reoriented, and 3D CT scans were 33%-61%, 44%-68%, and 49%-61%, respectively. A different mean SHSI was found for each imaging modality (conventional, 47%; reoriented, 56%; 3D, 55%; P ≤ .014), with the conventional SHSI showing an underestimation in 89% of the cases. GHSI thresholds for conventional, reoriented, and 3D CT scans were 40%-61%, 44%-56%, and 46%-54%, respectively. The mean GHSI did not differ between each imaging modality (conventional, 51%; reoriented, 50%; 3D, 50%; P = .146). The SHSI and GHSI are susceptible to different imaging modalities with consequently different cutoff values. The redefined HSI cutoff values guide physicians in the evaluation of humeral subluxation in conditions characterized by humeral displacement, depending on the available image data.

Three-Dimensional Computed Tomography Reconstruction in Transplant Renal Artery Stenosis.

Transplant renal artery stenosis is a frequently recognized complication of kidney transplant procedures. A single-center retrospective study was conducted to examine the use of 3-dimensional computed tomography reconstruction in diagnosing transplant artery stenosis. During 2013 at our center, 86 patients underwent kidney transplant. All patients underwent ultrasonographic analyses. Patients with clinically suspected transplant renal artery stenosis were examined by 3-dimensional computed tomography reconstruction and were treated with endovascular approaches or medically managed. Ten patients were diagnosed with transplant renal artery stenosis by 3-dimensional computed tomography reconstruction. No evidence of contrast-induced nephrotoxicity was observed. Nine of the 10 patients underwent percutaneous transluminal angio-plasty, whereas the remaining patient was treated conservatively. Procedural success rate was 100%. Patients were followed for a mean period of 20 ± 3 months. Blood pressure improved from a mean of 163/90 to 132/73 mm Hg at the end of the follow-up period. In the 9 patients who underwent angioplasty, serum creatinine improved from 198 ± 24 to 134 ± 16 μmol/L at the end of the follow-up period. The cystatin C level in some patients declined after interventional therapy. Three-dimensional computed tomography reconstruction is a safe choice for patients who present with increased serum creatinine levels and refractory hypertension. Percutaneous transluminal angioplasty is the preferred therapeutic technique for transplant renal artery stenosis.

Humeral head osteotomy in shoulder arthroplasty: a comparison between anterosuperior and inferoanterior resection techniques

The best chance that a shoulder arthroplasty will restore motion and muscle balance across the glenohumeral joint is by closely replicating natural articular morphology. Defining the humeral osteotomy plane along clear landmarks at the anatomic neck is critical. We hypothesized that a new osteotomy, based on alternative landmarks on the anatomic neck, would restore 3-dimensional humeral head morphology more reliably than the traditional osteotomy. The anatomic neck was digitized in 30 human cadaver shoulders and compared with its 3-dimensional computed tomography reconstruction. Two different osteotomy techniques were virtually performed: the traditional, following the anterosuperior anatomic neck; and a new technique, defined by the inferoanterior anatomic neck. The length-width difference and orientation (retroversion, inclination) of the resection area were compared between the techniques and with native anatomy. Length-width difference of the anterosuperior resection area was higher than in the inferoanterior osteotomy (6 ± 2 mm vs. 3 ± 1 mm; P < .001). Retroversion of the anterosuperior resection plane was higher than the native head (50° ± 12° vs. 37° ± 11°; P < .001), whereas retroversion after the inferoanterior osteotomy (32° ± 12°) did not differ from native (P = .057). Inclination differed after the anterosuperior osteotomy (129° ± 5°) and the inferoanterior osteotomy (127° ± 4°) compared with the native head (134° ± 4°; P ≤ .001). The inferoanterior referenced osteotomy generated a more circular resection area, matching the native humeral head retroversion more closely than in the anterosuperior technique. This study suggests that in shoulder arthroplasty, the humeral resection level should be referenced at the inferoanterior rather than the anterosuperior anatomic neck. Further studies should investigate the biomechanical effects of this alternative resection plane.

Fracture mapping of displaced partial articular fractures of the radial head

Recognition of patterns of traumatic elbow instability helps anticipate specific fracture characteristics and associated injuries. The objective of this study was to assess the association of fracture line distribution and location of displaced partial articular radial head fractures with specific patterns of traumatic elbow instability using fracture mapping techniques. Fracture line distribution and location of 66 acute displaced partial articular radial head fractures were identified using quantitative 3-dimensional computed tomography reconstructions that allowed reduction of fracture fragments and a standardized method to divide the radial head into quadrants with forearm in neutral position. Based on qualitative and quantitative assessment of fracture maps, the association between fracture characteristics of displaced partial articular radial head fractures and specific elbow fracture patterns was determined. In partial articular radial head fractures, the highest fracture line intensity was located in the anterolateral quadrant near the center of the radial head. Fracture location corresponded with fracture line distribution; most fractures involved the anterolateral quadrant (n = 65; 98%), whereas parts of the posteromedial quadrant were involved in a minority of the fractures (n = 10; 15%). The association of fracture line distribution and location with overall fracture patterns of the elbow, as depicted on fracture maps, was not statistically significant. Fracture maps demonstrated no association between fracture line distribution and location of displaced partial articular fractures of the radial head and overall specific patterns of traumatic elbow instability, suggesting a common fracture mechanism that involves the anterolateral part of the radial head in most patients.

Premorbid retroversion is significantly greater in type B2 glenoids

Posterior glenoid erosion is thought to be initiated by humeral head subluxation. However, it is unknown whether subluxation is entirely caused by soft-tissue instability and unbalanced muscle activity or whether osseous morphology is a contributing factor. We hypothesized that patients with posterior erosion may exhibit premorbid glenoid morphology that is inherently retroverted and inferiorly inclined compared with age-matched normal glenoids. This study examined 80 scapulae, evenly distributed between 2 groups: osteoarthritic with type B2 glenoids and age-matched normal glenoids. From 3-dimensional computed tomography reconstructions, version and inclination were measured from the anterior paleoglenoid region of the B2 glenoids, which is representative of the premorbid glenoid, and compared with measurements obtained from similar regions in the normal cohort. The anterior paleoglenoid region of B2 glenoids was significantly (P < .001) more retroverted (-14° ± 6°) compared with similar regions in nonarthritic normal glenoids (-5° ± 5°). There were no significant differences (P = .166) in the glenoid inclination angle between type B2 glenoids (0° ± 6°) and nonarthritic normal glenoids (2° ± 5°). Negative values represent retroverted and inferiorly inclined glenoids. Understanding premorbid glenoid morphologic variations may provide insight into the pathoanatomy of humeral head subluxation, osteoarthritis, and posterior glenoid erosion. The results of this study indicate that patients with type B2 osteoarthritic glenoids have significantly greater premorbid glenoid retroversion compared with nonarthritic normal glenoids, suggesting that this premorbid morphologic variation may be one contributing factor to posterior erosion.

Anthropometry of Arabian Arthritic Knees: Comparison to Other Ethnic Groups and Implant Dimensions

BackgroundWe aim to measure the proximal tibia and distal femur of the osteoarthritic knees of Arab patients and to compare these measurements with data on other ethnic groups available in literature and with the dimensions of 6 knee implants. MethodsAnteroposterior and mediolateral measurements of tibia and femur were done on 3-dimensional computed tomography reconstructions of 124 osteoarthritic knees undergoing total knee arthroplasty with patient-specific instruments. ResultsAverage mediolateral and anteroposterior dimensions of the tibia for Arab knees were 74.36 ± 6 mm and 48.94 ± 4.57 mm, respectively, whereas for femur, 72.04 ± 6.6 and 68.1 ± 7.75, respectively. Average aspect ratio for tibial was 152.62 ± 12.66 and for femur 106.37 ± 14.34. ConclusionThe size of Arab knees was generally smaller than Caucasian and larger than Asian. There is significant asymmetry of proximal tibial plateau and femur condyles.