Postoperative Computed Tomography Research Articles

Comparison of the quadrant method measuring four points and bernard method in femoral tunnel position evaluation on 3-dimensional reconstructed computed tomography after anatomical single-bundle anterior cruciate ligament reconstruction

PurposeThis prospective study aimed to compare the postoperative evaluation of the quadrant method measuring four points and Bernard method in femoral tunnel position evaluation on 3-Dimensional (3D) reconstructed computed tomography (CT) following the arthroscopic single-bundle anterior cruciate ligament (ACL) reconstruction.MethodsThirty-eight patients with ACL tears that were reconstructed using single-bundle ACL reconstruction between May 2021 and March 2023 were included in this study. Postoperative 3D CT images were obtained after the operation. The femoral tunnel position was measured by use of the quadrant method measuring four points and Bernard method.ResultsAverage mean position of the femoral tunnel insertion center on the 3D CT image was at 26.16 ± 6.27% in the x-coordinate and at 24.36 ± 5.52% in the y-coordinate according to the Bernard method. Meanwhile, the position of the femoral insertion of the ACL measured by the quadrant method measuring four points was 24.2% ± 6.86% in the x-coordinate and 21.16% ± 5.14% in the y-coordinate.ConclusionsBoth the quadrant method measuring four points and Bernard method were effective in femoral tunnel position evaluation on 3D reconstructed CT. Application of the quadrant method measuring four points on 3D CT showed the advantage that measurement can be taken regardless of the shape of the bone tunnel.

Differential Impact of Subcutaneous and Visceral Fat on Bone Changes after Gastrectomy.

Osteoporosis and fragility fractures are crucial musculoskeletal complications in long-term survivors of gastric cancer. However, the relationship between changes in body composition after gastrectomy and bone loss has not been investigated. Therefore, this study aimed to explore whether computed tomography (CT)-derived body composition parameters are associated with bone loss after gastrectomy in patients with gastric cancer. We retrospectively reviewed medical records and abdomen CT scans of patients who underwent gastrectomy at Yonsei University Severance Hospital between 2009 and 2018. Patients with non-metastatic gastric adenocarcinoma and preoperative and postoperative non-contrast CT scans were analyzed. Section area of skeletal muscle (SMA), visceral fat (VFA), and subcutaneous fat (SFA) were assessed using semi-automatic segmentation software. Changes in trabecular bone attenuation of L1 mid-vertebra level (L1 Hounsfield units [HU]) were measured. Fifty-seven patients (mean age, 65.5±10.6; 70.2% males) were analyzed, and the median duration was 31 months. Fortyseven patients (82.5%) lost weight after gastrectomy. Baseline SMA and VFA did not differ between the bone loss and preserved groups; however, baseline SFA was significantly higher in the bone preserved group than in the bone loss group (P=0.020). In a multivariable linear regression model adjusted for confounding factors, one standard deviation higher VFA at baseline was associated with greater annualized L1 HU loss (%) (P=0.034). However, higher preoperative SFA was associated with protection against bone loss after gastrectomy (P=0.025). Higher preoperative SFA exhibited a protective effect against bone loss after gastrectomy in patients with non-metastatic gastric cancer, whereas VFA exhibited a negative effect.

Progress of Ossification after Mandibular Reconstruction by Free Fibula Flap Depending on Different Timing of Radiotherapy: A Retrospective 3D Analysis by CT Scans

Background: The aim of this study was to evaluate the difference between pre- and post-operative radiotherapy on the progress of ossification after free fibula flap reconstruction of the mandible using three-dimensional (3D) analysis. Methods: A total of 38 free fibula reconstructions of the mandible were evaluated retrospectively for ossification between bone segments by measuring Hounsfield Units (HU) in at least two postoperative computer tomography scans (average of 2.4 scans per patient; around the 5th, 12th, 16th, and 19th month postoperative). Three subgroups were created according to the time of irradiation: preoperative radiotherapy (preORT) (n = 11), postoperative radiotherapy (postORT) (n = 16), and patients without any radiation therapy (n = 11) as the control group (noRT). HU in eight regions of interest (ROI) and overlapping surfaces between segments per contact point, as well as influencing factors, were analyzed. Results: The fastest progress in gain of HU ossification with a difference of 0.30 HU/day was observed in noRT compared to preORT (p = 0.002). postORT was −0.24 HU/day slower than preORT (p = 0.005). Original and grafted bone showed a significantly slower HU uptake than between two graft segments with −84.18 HU/day (p < 0.001). Moreover, a larger initial overlapping surface between the segments in cm2 resulted in a higher rise of HU/day (p < 0.001). Conclusions: 3D analysis of post-reconstructive CT scans shows prolonged ossification of mandible reconstructions by free fibula after head and neck radiation. The effect is distinct in cases with post-operative adjuvant radiotherapy. The effects of radiotherapy on ossification may be minimized by a larger initial contact surface and improved operational techniques. Moreover, HU longitudinal measurements and 3D analysis offer new perspectives for clinical evaluation of successful bony healing.

Fully automated determination of robotic pedicle screw accuracy and precision utilizing computer vision algorithms

Historically, pedicle screw accuracy measurements have relied on CT and expert visual assessment of the position of pedicle screws relative to preoperative plans. Proper pedicle screw placement is necessary to avoid complications, cost and morbidity of revision procedures. The aim of this study was to determine accuracy and precision of pedicle screw insertion via a novel computer vision algorithm using preoperative and postoperative computed tomography (CT) scans. Three cadaveric specimens were utilized. Screw placement planning on preoperative CT was performed according to standard clinical practice. Two experienced surgeons performed bilateral T2–L4 instrumentation using robotic-assisted navigation. Postoperative CT scans of the instrumented levels were obtained. Automated segmentation and computer vision techniques were employed to align each preoperative vertebra with its postoperative counterpart and then compare screw positions along all three axes. Registration accuracy was assessed by preoperatively embedding spherical markers (tantalum beads) to measure discrepancies in landmark alignment. Eighty-eight pedicle screws were placed in 3 cadavers’ spines. Automated registrations between pre- and postoperative CT achieved sub-voxel accuracy. For the screw tip and tail, the mean three-dimensional errors were 1.67 mm and 1.78 mm, respectively. Mean angular deviation of screw axes from plan was 1.58°. For screw mid-pedicular accuracy, mean absolute error in the medial–lateral and superior–inferior directions were 0.75 mm and 0.60 mm, respectively. This study introduces automated algorithms for determining accuracy and precision of planned pedicle screws. Our accuracy outcomes are comparable or superior to recent robotic-assisted in vivo and cadaver studies. This computerized workflow establishes a standardized protocol for assessing pedicle screw placement accuracy and precision and provides detailed 3D translational and angular accuracy and precision for baseline comparison.

366 A Case Study: Application of Personalised External Aortic Root Support to Overcome a Failing Ross Procedure

Abstract Aortic root aneurysms are traditionally treated by aortic root replacement surgery alone or in combination with aortic valve replacement in a Modified Bentall procedure. We present a novel surgical approach using a Personalised External Aortic Root Support (PEARS) in the management of an aortic root aneurysm in a 24-year-old male, initially presenting in infancy with mixed aortic valve disease who underwent a free root Ross procedure in 2010 aged 11. Follow-up cardiac magnetic resonance imaging and transthoracic echocardiography showed mild aortic and pulmonary valve regurgitation with aortic root dilatation (51mm). In 2022, Computerised tomography (CT) exhibited dilation of the Sinus of Valsalva (43mm) and ascending aorta (56 mm). MDT review deemed redo valve-sparing root replacement appropriate as the ascending aorta was >55mm with an approximate 8mm increase over three years. As the young patient wished to avoid warfarinisation and the autograft valve maintained good function, a reduction PEARS was considered. In September 2023, a reduced aortic PEARS graft (80% reduction) was implemented along with a redo of the right ventricle to pulmonary artery conduit. Whilst applying the PEARS it was noted that there was a retroaortic circumflex artery, care was taken to mobilise this aberrant vessel to avoid compression by the graft. Cardiopulmonary bypass and cross-clamp times were 180 and 116 minutes respectively. Intraoperative transoesophageal echocardiography confirmed good bi-ventricular function with no pulmonary regurgitation additionally on postoperative CT the aortic diameter was 38mm. In conclusion, application of a reduction PEARS is a potential alternative to a valve-sparing aortic root replacement method in young patients.

Mini-Invasive Endoscope-Assisted Treatment of Metopic Craniosynostosis: 2-Dimensional Operative Video.

The surgical treatment of trigonocephaly has undergone significant evolution, with an increasing use of a minimally invasive technique. The endoscope-assisted metopic suturectomy is currently considered a valid surgical option for the correction of metopic craniosynostosis.1-5 In this video-article, we present our surgical technique performed on a 5-month-old patient with type III (Genitori's classification6) trigonocephaly. The computed tomography (CT) scan showed fusion of the metopic suture with bitemporal narrowing and hypotelorism. The patient underwent endoscope-assisted metopic suturectomy, the width of the suturectomy is 1 cm, and an Esmarch sheet was used to protect the dura mater while drilling. Bridging veins are coagulated under endoscopic vision. The suturectomy is considered complete when the nasal cartilages are exposed, deconnecting thus completely the orbits. The postoperative CT scan showed the extent of the suturectomy. The patient did not present any neurological deficit or complications after surgery and was discharged on postoperative day 2. No helmet was used postoperatively. The patient repeated a head CT at age 11 years after head trauma and was seen at consultation. Interestingly, once the bone gap created after the metopic suturectomy reossifies, the frontal sinus develops normally. The long-term result was quite satisfying. The advantages of the mini-invasive technique consist in a smaller surgical scar, lower blood loss, shorter surgical time, and shorter hospital stay with good long-term results. The parents provided written consent for the publication of the patient's picture, the institutional research board approved the submission of this video article. In the video, the tips, tricks, and pitfalls of the technique are discussed.

Steel bar penetrating cervical spinal canal without neurological injury: A case report

BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures. CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck, without signs of neurological deficit. Computed tomography (CT) demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level, causing C6 and C7 vertebral body fracture, C6 left lamina fracture, left facet joint fracture, and penetration of the cervical spinal cord. The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team. During the surgery, we found that the cervical vertebra, cervical spinal canal and cervical spinal cord were all severely injured. Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits. CONCLUSION Even with a serious cervical spinal canal penetrating trauma, the patient could resume normal work and life after appropriate treatment.

A navigated, robot-driven laser craniotomy tool for frameless depth electrode implantation. An in-vivo recovery animal study.

Objectives: We recently introduced a frameless, navigated, robot-driven laser tool for depth electrode implantation as an alternative to frame-based procedures. This method has only been used in cadaver and non-recovery studies. This is the first study to test the robot-driven laser tool in an in vivo recovery animal study. Methods: A preoperative computed tomography (CT) scan was conducted to plan trajectories in sheep specimens. Burr hole craniotomies were performed using a frameless, navigated, robot-driven laser tool. Depth electrodes were implanted after cut-through detection was confirmed. The electrodes were cut at the skin level postoperatively. Postoperative imaging was performed to verify accuracy. Histopathological analysis was performed on the bone, dura, and cortex samples. Results: Fourteen depth electrodes were implanted in two sheep specimens. Anesthetic protocols did not show any intraoperative irregularities. One sheep was euthanized on the same day of the procedure while the other sheep remained alive for 1 week without neurological deficits. Postoperative MRI and CT showed no intracerebral bleeding, infarction, or unintended damage. The average bone thickness was 6.2 mm (range 4.1-8.0 mm). The angulation of the planned trajectories varied from 65.5° to 87.4°. The deviation of the entry point performed by the frameless laser beam ranged from 0.27 mm to 2.24 mm. The histopathological analysis did not reveal any damage associated with the laser beam. Conclusion: The novel robot-driven laser craniotomy tool showed promising results in this first in vivo recovery study. These findings indicate that laser craniotomies can be performed safely and that cut-through detection is reliable.

Accelerated fusion dynamics by recombinant human bone morphogenetic protein-2 following transforaminal lumbar interbody fusion, particularly in osteoporotic conditions

BACKGROUND CONTEXTEarly fusion is crucial in interbody procedures to minimize mechanical complications resulting from delayed union, especially for patients with osteoporosis. Bone morphogenetic proteins (BMPs) are used in spinal fusion procedures; however, limited evaluation exists regarding time-to-fusion for BMP use, particularly in patients with osteoporosis. PURPOSETo evaluate the difference in time-to-fusion after single-level transforaminal lumbar interbody fusion (TLIF) surgery between recombinant human bone morphogenetic protein-2 (rhBMP-2) usage and nonusage groups according to bone density. STUDY DESIGNRetrospective single-center cohort study. PATIENT SAMPLEThis study enrolled 132 patients (mean age, 65.25±8.66; male patients, 40.9%) who underwent single-level TLIF for degenerative disorders between February 2012 and December 2021, with pre and postoperative computed tomography (CT). OUTCOME MEASUREThe interbody fusion mass and bone graft status on postoperative CT scans was obtained annually, and time-to-fusion was recorded for each patient. METHODSThe patients were divided into 2 groups based on rhBMP-2 use during the interbody fusion procedure. Patients were further divided into osteoporosis, osteopenia, and normal groups based on preoperative L1 vertebral body attenuation values, using cutoffs of 90 and 120 Hounsfield units. It was strictly defined that fusion is considered complete when a trabecular bone bridge was formed, and therefore, the time-to-fusion was measured in years. Time-to-fusion was statistically compared between BMP group and non-BMP groups, followed by further comparison according to bone density. RESULTSThe time-to-fusion differed significantly between BMP and non-BMP groups, with half of the patients achieving fusion within 2.5 years in the BMP group compared with 4 years in the non-BMP group (p<.001). The fusion rate varied based on bone density, with the maximum difference observed in the osteoporosis group, when half of the patients achieved fusion within 3 years in the BMP group compared to 5 years in the non-BMP group (p<.001). Subgroup analysis was conducted, revealing no significant associations between time-to-fusion and factors known to influence the fusion process, including age, gender, medical history, smoking and alcohol use, and medication history, except for rh-BMP2 use and bone density. CONCLUSIONSRhBMP-2 usage significantly reduced time-to-fusion in single-level TLIF, especially in patients with osteoporosis. LEVEL OF EVIDENCELevel III.

Comparison of range of motion between 2-year clinical outcomes and predictions of a static scapula preoperative planning software for reverse shoulder arthroplasty

BackgroundPreoperative planning has gained popularity in the management of reverse shoulder arthroplasty (RSA). Commercially available software provides 3-dimensional segmentation of scapula and humerus, as well as providing arc of motion for the implanted articulation and identifying potential areas of bony impingement. However, these software algorithms use a fixed scapula model, disregarding the preoperative clinical range of motion (C-ROM) of the patient, be it glenohumeral or scapulothoracic, as well as any soft tissue parameters. This study aims to compare the ROM based on preoperative planning software by using the implant position from postoperative computed tomography (CT) images (predicted ROM using preoperative planning software [P-ROM]), with the C-ROM assessed at minimum of 2 years of follow-up. MethodsPreoperative and postoperative CT scans of 46 patients who underwent primary RSA between 2017 and 2021 were analyzed. At the postoperative 2-year review, each patient was assessed for active ROM. Implant size and position based on operative notes and postoperative CT scans were used to replicate the performed surgery in the planning software. Abduction, flexion, and external rotation motion were simulated and recorded. The relationship between C-ROM and P-ROM was investigated using linear regression analysis, Pearson correlation coefficient, and paired t-test. ResultsP-ROM was significantly lower than C-ROM at 2 years postoperatively (P < .001), with an average discrepancy of 78° in abduction, 47° in flexion, and 37° in external rotation (C-ROM: abduction 155° ± 21° [80°-180°]; flexion 160° ± 17° [90°-180°]; external rotation 52° ± 14° [10°-80°] vs. P-ROM: abduction 77° ± 13° [53°-107°]; flexion 112° ± 25° [67°-180°]; external rotation 15° ± 21° [0°-79°]). The linear regression analysis indicated weak agreement between C-ROM and P-ROM (abduction R2 = 0.03; flexion R2 = 0.01; external rotation R2 = 0.04). Pearson’s correlation coefficients revealed weak correlations of −0.18, 0.03, and 0.21 for abduction, flexion, and external rotation, respectively. ConclusionP-ROM based on preoperative software in its current form does not allow the prediction of the C-ROM at 2 years of follow-up for patients undergoing RSA.

Clinical decompensation after trauma laparotomy: It's probably not a pulmonary embolus

Introduction Computed Tomography (CT) to rule out pulmonary embolus (PE) is often ordered during post-trauma laparotomy clinical decompensation (CD) involving fever, tachycardia, tachypnea, and/or leukocytosis. We hypothesize this diagnostic modality is low-yield in the postoperative period when surgery-related sequelae are more probable.Methods This is a single-center retrospective cohort study of patients who underwent trauma laparotomy and had subsequent CT for CD from March 19, 2019 to June 30, 2022. Descriptive statistics and multiple logistic regression were performed. The primary outcome was saddle and lobar PE incidence.Results 1032 adult patients underwent trauma laparotomy with 434 undergoing CT for CD: 137 CT abdomen and pelvis only, 30 CTPE, 265 both. The majority (80.2 %) was male, age 33[interquartile range (IQR) 24–45], suffered penetrating mechanism (57 %), and had ISS 23[IQR16–30]. Injuries at laparotomy included 47 % solid organ, 62 % GI tract, 7 % biliary, 11 % vascular, and 42 % other. 176 (41 %) required damage control laparotomy. Median time to CT post-laparotomy was 174 h [111–235] with saddle and lobar PE in 3 (1 %), peripheral PE 18 (5 %), and abdominal abscess, leak, fluid, or pseudoaneurysm in 222 (51 %). Clinical management was altered (40 %) by antibiotics, therapeutic anticoagulation, drainage, aspiration, filter, thrombectomy, or surgical operation. Patients for whom CT findings changed management were more likely to have had GI tract surgery (69% vs 57 %, p = 0.021), higher white blood cell (WBC) (16.4 [13.1–20.5] vs 15.1 [9.9–19.5], p = 0.002), more hours between CT and laparotomy (184 [141–245] vs 162 [89–230], p = 0.002), and lower mortality (2% vs 8 %, p = 0.008). In-hospital mortality was 5 %; none were PE-related. Predictors of clinical intervention required based on CT imaging were GI tract injury (AOR: 1.65, p = 0.0182), and elevated WBC (AOR: 1.038, p = 0.010Conclusion Saddle and lobar PE incidence post-trauma laparotomy is low. SIRS-type symptoms prompting postoperative CT commonly have no procedural or antibiotic requirement. Postoperative decompensation is more likely related post-operative complications, and less likely a PE.

Comparative Study for Surgical Treatment of Acute Distal Tibiofibular Syndesmotic Lesions Using the Modified Suture-Button Fixation Versus Static Syndesmotic Screw Fixation.

Several techniques to treat acute distal tibiofibular instability are described consisting in static and dynamic fixation procedures. The aim of our work is to compare the outcomes of acute syndesmotic injury fixation between the modified technique of dynamic fixation using the suture-button principle as an efficient and low-cost method and the classic static fixation. It is a prospective study including patients presenting with acute syndesmotic injury. After fracture fixation, residual syndesmotic instability was managed using syndesmotic screw in group A and dynamic fixation with a double Ethibond suture in group B. Functional results were assessed using the American Orthopaedic Foot and Ankle Society score (AOFAS) score. Radiological evaluation was done by a postoperative computed tomography (CT) scan of both ankles and plain X-rays of the ankle after surgery and at 18 months. Group A included 20 patients meanwhile 35 patients were in group B. The reduction was satisfactory in the 2 groups according to the postoperative CT scan measurements. The mean healing time in group A was 49.65 days and 51.49 days in group B (P = .45). We did not find any significant difference in terms of loss of reduction in the 2 groups. The return to work was faster in group B (P = .04). Patients in group B had better AOFAS score (P = .03) and ankle range of motion than those in group A. The difference was statistically significant (P = .02 for dorsal flexion and P = .001 for plantar flexion). For group A, we did not note any early complications. Meanwhile, 7 patients developed skin complications in group B (P = .03). However, no significant difference was found in terms of late complications. The modified dynamic suture-button fixation remains a therapeutic alternative in low-income countries that could achieve better outcomes than static fixation, with easy postoperative follow-up. Level II.

Ipsilateral pubic ramus fracture during total hip arthroplasty is not rare: does it matter?

Periprosthetic fractures in total hip arthroplasty (THA) have been well described and studied. However, there is a lack of reports on ipsilateral pubic ramus fractures during THA due to the rare occurrence of such fractures and ambiguity of symptoms. With the use of postoperative computed tomography (CT) examinations, we have identified that asymptomatic ipsilateral pubic ramus fractures occur frequently during THA. This study aims to evaluate the incidence, location, clinical outcomes, and risk factors of ipsilateral pubic ramus fractures during THA. From May 2022 to March 2023, a single surgeon performed 203 THAs in 183 patients at a single institution. All patients underwent postoperative CT scans three days after THA. The patients with ipsilateral pubic ramus fractures were followed up for a minimum of six months. Basic demographics, osteoporosis, general conditions of the operations, and outcomes of THA were investigated in all patients. Twenty-two cases (10.8%) of ipsilateral pubic ramus fractures were identified on postoperative CT scans. All fractures were located near the origin of the superior or inferior pubic ramus. Five fractures were detected on simple postoperative radiographs. The fractures did not cause any further complications at a minimum of six-month postoperative follow-up. Univariate and multivariate analyses did not identify any risk factors associated with these fractures. Although the incidence of ipsilateral pubic ramus fractures during THA is high, treatment is not required as they do not cause any significant clinical symptoms or affect the prognosis of THA. However, the possibility of occurrence of these fractures must be explained to the patients before surgery.

Post-operative MRI synthesis from pre-operative MRI and post-operative CT using conditional GAN for the assessment of degree of resection

BackgroundMagnetic resonance imaging (MRI) is an essential part of assessing the extension of resection after craniotomy, allowing for accurate assessment of the brain. However, the application of MRI within 72 h after surgery is limited, owing to its high cost, long time duration, and patients’ limited mobility. Besides, MRI excludes people with contraindications, in which sceneries computerized tomography (CT) is the only available choice. To overcome these limitations, we investigated the use of a deep learning model for synthesizing post-operative MRI images. MethodsWe employed Cross-domain Correspondence Learning for Exemplar-based Image Translation Network (CoCosNet), an exemplar-based image translation model to synthesize T1 contrast-enhanced (T1ce) MRI images by combining post-operative T1ce and post-operative CT images. 233 cases were retrospectively collected at Sun Yat-sen University Cancer Center and underwent complete MRI and CT scans. ResultsAfter 200 epochs and a batch size of 10, CoCosNet achieved comparable results compared to other existing models, with objective indicators structural similarity index = 0.75, peak signal to noise ratio = 21.68, and mean absolute error = 0.007. Furthermore, assessments of the extension of resection between the true and synthesized T1ce images achieve great consistency. ConclusionsOur study demonstrates the effectiveness of the CoCosNet model in synthesizing post-operative MRI images from pre-operative MRI and post-operative CT scans. Quantitative analysis indicates that the synthesized images have comparable quality to real MRI images and can accurately discriminate the extent of resection. This approach has a promising future by providing a reliable alternative to traditional post-operative MRI.

Intentional Insertion of Air to Predict the Diagnostic Accuracy of Stereotactic Biopsy and a Uniform Grading System for Reporting

Background and Objectives: Stereotactic biopsies are a relatively safe and reliable way of tissue diagnosis and characterization of eloquent area lesions/neoplasm. However, predicting the accuracy of the site of biopsy with the desired/planned site is not always possible. We describe a technique to identify the precise location of the biopsy site in the post-operative computed tomography (CT) scan using the injection of a low volume of air into the biopsy cannula. Methods: Hundred consecutive biopsies were performed in 80 adults/20 children (59 males/41 females, median age 51 years) over 3 years, consisting of 75 frameless and 25 frame-based stereotactic biopsies. After the biopsy specimens had been collected, a small volume of air (median 1 cc) was injected into the site. Post-operative CT was done within 4 hours of the biopsy to see the site of the air bubble, and the same was correlated with the histopathological accuracy. Results: Intra-cranial air in the selected target was present in 95 patients (Grade 1 and 2), while the air was seen in the track (Grade 3) in 3% and at an unrelated site (Grade 4) in 2% of cases. Both Grade 4 biopsies were negative on histopathology (diagnostic yield = 98%). Two negative biopsies were reported, which were both predicted with the Grade 4 biopsy. The grading allowed uniform reporting across series and eliminated the chance of upgrading/downgrading the report due to wrong site sampling within the lesion/neoplasm. Conclusion: The air-injection manoeuvre proposed for use in stereotactic biopsies of intra-cranial mass lesions is a safe and reliable technique that allows the exact biopsy site to be located without any related complications.

Predictors of Late Adverse Events in Patients with Surgically Treated Type I Aortic Dissection

Residual aortic dissection (AD) following DeBakey type I AD repair is associated with a high rate of adverse events that need additional intervention or surgery. This study aimed to identify clinical and early post-operative computed tomography (CT) imaging factors associated with adverse events in patients with type I AD after ascending aorta replacement. This single centre, retrospective cohort study included consecutive patients with type I AD who underwent ascending aorta replacement from January 2011 to December 2017 and post-operative CT within 3 months. The primary outcome was AD related adverse events, defined as AD related death and re-operation due to aortic aneurysm or impending rupture. The location and size of the primary intimal tears, aortic diameter, and false lumen status were evaluated. Regression analyses were performed to identify factors associated with AD related adverse events. A decision tree model was used to classify patients as high or low risk. Of 103 participants (55.43 ± 13.94 years; 49.5% males), 24 (23.3%) experienced AD related adverse events. In multivariable Cox regression analysis, connective tissue disease (hazard ratio [HR] 15.33; p < .001), maximum aortic diameter ≥ 40 mm (HR 4.90; p < .001), and multiple (three or more) intimal tears (HR 7.12; p < .001) were associated with AD related adverse events. The 3 year cumulative survival free from AD related events was lower in the high risk group with aortic diameter ≥ 40 mm and multiple intimal tears (41.7% vs. 90.9%; p < .001). Early post-operative CT findings indicating a maximum aortic diameter ≥ 40 mm and multiple intimal tears may predict a higher risk of adverse events. These findings suggest the need for careful monitoring and more vigilant management approaches in these cases.

Finite element analysis of acromial fracture after reverse total shoulder arthroplasty

BackgroundThe prevalence of acromial fracture after reverse total shoulder arthroplasty (RSA) is reportedly 2.6%-8.4%, and clinical outcomes differ among fracture sites. However, few studies have investigated the factors affecting fracture sites. This study aimed to reproduce acromial fractures after RSA by replicating the postoperative displacement of the humerus using finite element models (FEMs), and to investigate the effect of humeral displacement on the fracture site. MethodsSix patients (mean age, 76.3 ± 7.9 years; 5 women and 1 man) with acromial fractures after RSA treated at our institution were included. Among them, 3 had Levy Type 1 fractures, whereas the other 3 had Levy Type 2 fractures. Preoperative computed tomography data were used to create a 3-dimensional FEM. All elements within the proximal 2 cm of the clavicle and the scapular body were completely constrained. The entire humerus was forcibly displaced following its displacement after RSA, as measured by preoperative and postoperative computed tomography. The fracture sites, total displacement, external constraint of the humerus at the initial fracture, and bone density from the acromion to the scapular spine were investigated. Values of P < .05 were considered statistically significant in tests of statistical inference but were interpreted as reference values due to the small number of cases. ResultsThere were no major differences in humeral displacement between Type 1 and Type 2 fractures. Although the fracture sites in the FEM were slightly more medial than the actual fracture sites, they were similar. The total displacement and external constraint of the humerus at the initial fracture were similar in Type 1 and Type 2 fractures. The distribution of bone density from the acromion to the scapular spine differed between fracture types. ConclusionWe were able to reproduce acromial fractures after RSA by replicating humeral displacement using FEM. The extent and direction of humeral displacement may not significantly affect the acromial fracture site, whereas the bone density distribution from the acromion to the scapular spine may affect it.

Accuracy of portable navigation during THA in patients with severe developmental dysplasia of hip.

Correct cup placement in total hip arthroplasty (THA) for patients with developmental dysplasia of the hip (DDH) is considerably difficult. This study aimed to analyze the orientation accuracy of cup insertion during THA using a portable navigation system in patients with DDH. In this retrospective cohort study, we analyzed data from 64 patients who underwent THA using infrared stereo camera-matching portable navigation. Patients underwent THA via the anterolateral approach in the lateral decubitus position. Navigation records for intraoperative cup angles, postoperative cup angles measured on computed tomography (CT) images, and cup angle measurement differences were measured and compared between patients with non-DDH/mild DDH and severe DDH. Furthermore, the predictive factors for outliers of accurate acetabular cup placement were analyzed. The average measurement absolute abduction differences (postoperative CT-navigation record) were 3.9 ± 3.5° (severe DDH) and 3.3 ± 2.6° (non-DDH/ mild DDH), and the anteversion differences were 4.7 ± 3.4° (severe DDH) and 2.3 ± 2.1° (non-DDH/ mild DDH). The anteversion difference was different between the two groups. Multivariate analysis showed that the navigation difference (absolute difference in anteversion between postoperative CT and navigation records of > 5°) was significantly associated with severe DDH (odds ratio [OR]: 3.3; p = 0.049, 95% confidence interval [CI]: 1.0-11.1) and posterior pelvic tilt (OR: 1.1; p = 0.042, 95% CI: 1.0-1.27). In patients with severe DDH, it is important to pay close attention during THA using portable navigation. However, the average difference was < 5º even in patients with severe DDH, and the accuracy may be acceptable in a clinical setting when the cost is considered.

Comparison between accuracy of augmented reality computed tomography-based and portable augmented reality-based navigation systems for cup insertion in total hip arthroplasty

Augmented reality (AR) has been used for navigation during total hip arthroplasty (THA). AR computed tomography (CT)-based navigation systems and AR-based portable navigation systems that use smartphones can also be used. This study compared the accuracy of cup insertion during THA using AR-CT-based and portable AR-based navigation systems. Patients with symptomatic hip disease who underwent primary THA in the supine position using both AR CT-based and portable AR-based navigation systems simultaneously between October 2021 and July 2023 were included. The primary outcome of this study was the absolute difference between cup angles in the intraoperative navigation record and those measured on postoperative CT. The secondary outcome was to determine the factors affecting the absolute value of the navigation error in radiographic inclination (RI) and radiographic anteversion (RA) of the cup, including sex, age, body mass index, left or right side, approach, and preoperative pelvic tilt. This study included 94 consecutive patients. There were 11 men and 83 women, with a mean age of 68 years. The mean absolute errors of RI were 2.7° ± 2.0° in the AR CT-based and 3.3° ± 2.4° in the portable AR-based navigation system. The mean absolute errors of RA were 2.5° ± 2.1° in the AR CT-based navigation system and 2.3° ± 2.2° in the portable AR-based navigation system. No significant differences were observed in RI or RA of the cup between the two navigation systems (RI: p = 0.706; RA: p = 0.329). No significant factors affected the absolute value of the navigation errors in RI and RA. In conclusion, there were no differences in the accuracy of cup insertion between the AR CT-based and portable AR-based navigation systems.

Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.