Axial Computed Tomography View Research Articles

[Translated article] Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries

IntroductionThe main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. MethodologyRetrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. ResultsForty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. ConclusionWe advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Inserción de tornillos iliosacros S1 en la sala de tomografía computarizada. Una alternativa para mejorar la seguridad en el tratamiento percutáneo de las lesiones posteriores del anillo pélvico

IntroductionThe main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. MethodologyRetrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. ResultsForty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. ConclusionWe advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Improving Safety in Chondrolaryngoplasty.

Improving Safety in Chondrolaryngoplasty.

Preoperative computed tomography predicts the risk of recurrent laryngeal nerve paralysis in patients with esophageal cancer undergoing thoracoscopic esophagectomy in the prone position.

Recurrent laryngeal nerve paralysis (RLNP) after thoracoscopic esophagectomy for esophageal cancer (EC) is known to be a major complication leading to poor quality of life. RLNP is mainly associated with surgical procedures performed near the RLN. Therefore, with focus on the region of the RLN, we used preoperative computed tomography to investigate the risk factors of RLNP in patients with EC undergoing thoracoscopic esophagectomy. We retrospectively examined 77 EC patients who underwent thoracoscopic esophagectomy in the prone position at our department between January 2010 and December 2018. Bilateral cross-sectional areas (mm2) of the fatty tissue around the RLN at the level of the lower pole of the thyroid gland were measured on preoperative axial computed tomography (CT) images. Univariate and multivariate logistic regression analysis was used to evaluate the association between the incidence of RLNP and patient clinical factors, including the cross-sectional areas. RLNP occurred in 24 of 77 patients (31.2%). The incidence of RLNP was significantly more frequent on the left side than on the right. (26% vs. 5.2%, respectively). Univariate analysis identified the following left RLNP risk factors: intrathoracic operative time (> 235min), and area around the RLN (> 174.3 mm2). Multivariate analysis found that the area around the RLN was an independent risk factor of left RLNP. An increased area around the RLN measured on an axial CT view at the level of the lower pole of the thyroid gland was a risk factor of RLNP in EC patients undergoing thoracoscopic esophagectomy in the prone position.

Comparison of clinical outcome between pyeloperfused versus non-pyeloperfused microwave ablation of renal cell carcinoma.

PurposeWe present the outcomes of microwave ablation (MWA) of renal cell carcinoma (RCC) with and without pyeloperfusion.Material and methodsA retrospective review of patients’ records was undertaken to identify patients with RCC, who were treated with MWA with and without adjunctive pyeloperfusion. The distance between the tumour and ureter as well as the tumour size were measured on axial imaging. Pyeloperfusion was performed in nine patients in this series after placement of a ureteral stent and instilment of diluted contrast into the ureter. MWAs of the tumours were performed under computed tomography (CT) guidance. Hydrodissection was performed to displace at-risk organs. Creatinine was measured as renal function index after and before the procedure. A CT scan was performed at the end of the procedure and also after one, three, and six months, to identify the presence of residual disease and complications.ResultsEighteen biopsies of proven RCC were treated with 20 sessions of MWA. The average follow-up time for this study was 180 days. The average distance between the ureter and the tumour in axial CT view was 20.8 (± 2.9) mm. Primary efficacy was achieved in 88% of pyeloperfused patients and in 100% of the non-pyeloperfused patients. Two pyeloperfused patients required secondary procedure, and full secondary efficacy was achieved for both. There was only one grade 2 urological complication, which occurred in a patient who underwent pyeloperfusion. Creatinine was not significantly different after the procedure in this study (p-value 0.4).ConclusionIn this study MWAs of RCCs were successfully performed using pyeloperfusion as a protective measure against thermal injury to the ureter.

A Novel Approach Using Computed Tomography Angiograms to Predict Sternotomy or Complicated Anastomosis in Patients Undergoing Robotically Assisted Minimally Invasive Direct Coronary Artery Bypass.

Robotically assisted minimally invasive direct coronary artery bypass is an alternative to sternotomy-based surgery in properly selected patients. Identifying the left anterior descending artery when it is deep in the epicardial fat can be particularly challenging through a 5- to 6-cm mini-thoracotomy incision. The objective of this study was to evaluate a technique for predicting conversion to sternotomy or complicated left anterior descending artery anastomosis using preoperative cardiac-gated computed tomography angiograms. Retrospective review of 75 patients who underwent robotically assisted minimally invasive direct coronary artery bypass for whom a preoperative computed tomography angiogram was available. The distance from the left anterior descending artery to the myocardium was measured on a standardized "5-chamber" axial computed tomography view. The relative risk of sternotomy or complicated anastomosis was compared between patients whose left anterior descending artery was resting directly on the myocardium (left anterior descending artery to the myocardium distance = 0 mm) with those whose left anterior descending artery was resting above (left anterior descending artery to the myocardium distance > 0 mm). The average left anterior descending artery to the myocardium distance was 3.2 ± 2.6 mm (range = 0-11.5 mm). Fourteen patients (18.7%) had an left anterior descending artery to the myocardium distance of 0 mm. Of the entire group of 75 patients, 6 (8.0%) required conversion to sternotomy. Four others (5.3%) were reported to have a complication with the anastomosis intraoperatively. For patients with left anterior descending artery to the myocardium distance of 0 mm, the relative risk of sternotomy or complicated anastomosis was 18.0 (95% confidence interval = 4.3-75.6, P = 0.0001). In our experience, patients with left anterior descending artery to the myocardium distance of 0 mm were at significantly higher risk of either conversion to sternotomy or technically challenging anastomosis, with 8 (57.1%) of 14 patients in this group experiencing either end point. This novel measurement may be useful to identify patients who may have anatomy, which is not well suited to the robotically assisted minimally invasive direct coronary artery bypass approach.

Surgical treatment of middle aortic syndrome due to Takayasu arteritis

A 35-year-old Korean female patient presented with symptoms of postprandial pain and claudication in both lower extremities, with increasing serum creatinine. Her blood pressure at presentation was 170/91 mm Hg on antihypertensive medications, and blood tests showed elevated serum creatinine (2.07 mg/dL) and erythrocyte sedimentation rate (39 mm/dL), and anemia (10.0 g/dL). The C-reactive protein level was within the normal reference range (0.2 mg/dL). A three-dimensional volume-rendered image of a posterior view thoracoabdominal computed tomography (CT) scan showed a heavily calcified distal thoracic and abdominal aorta and a contracted left kidney (A). The axial CT view showed the paravisceral aortic diameter was narrowed to 5.5 mm (B). On a diagnosis of middle aortic syndrome (MAS) due to Takayasu arteritis (TA), we performed an aortic bypass from the ascending aorta to the aortic bifurcation in conjunction with revascularization of the right renal and superior mesenteric arteries. On postoperative day 1, the patient’s serum creatinine level recovered to a normal range and her postprandial abdominal pain subsided. A postoperative CT angiogram showed patent aortic, renal, and mesenteric bypass grafts (C/Cover).

Polymethylmethacrylate augmentation of the pedicle screw: the cement distribution in the vertebral body

Many studies have proven that the polymethylmethacrylate (PMMA) augmentation of the pedicle screw can significantly increase stiffness and strength of spinal fixation. Some major complications have also been reported. However, there are no reports discussing cement distribution and its morphology in the osteoporotic vertebral body, which is critical in the analysis of the biomechanical strength of the pedicle screw and the risk of cement leakage after pedicle screw augmentation. In this study, we used computed tomography (CT) to evaluate the cement distribution in the osteoporotic vertebral body after PMMA augmentation of a pedicle screw and to analyze the factors leading to cement leakage. Two groups of patients were studied. Group A consisted 25 osteoporotic patients (mean age of 73years) with spinal instrumentation who had a total of 145 pedicle screws and cement augmentation with biopsy needles. Group B consisted of 23 osteoporotic patients (mean age of 74.6years) with spinal instrumentation who had a total of 125 cannulated pedicle screws with cement augmentation. All patients had CT evaluation of the cement distribution in the vertebral body after the surgery. The cement distribution in the vertebrae was divided into four zones in the axial CT view: anterior one-third, middle third, and posterior third of vertebral body, and the pedicle. The morphology of the cement distribution around the pedicle screw was defined as scattered type or concentrate type. The leakage pattern was divided to anterior-lateral, posterior-lateral, and canal leakage. The correlations among bone mineral density (BMD), the cement leakage rate, and cement distribution morphology were also analyzed. The results showed that most augmented pedicle screws had cement extension into three of the four zones of the vertebral body (66.3%), followed by two zones (20%), all four zones (11.5%), and only one zone (2.2%). Overall, 123 screws (84.8%) in Group A and 108 screws (86.4%) in Group B had cement concentrate type distribution. The cement leakage rate in Group A is 18.3% and 13.6% in Group B. Patients with a BMD <0.6g/cm(2) had significantly higher rates of cement leakage and tended toward a scattered cement distribution. There was only one patient who had a symptomatic leakage (sciatica) in Group B. We concluded that the cement distribution after pedicle screw augmentation with biopsy needle or cannulated screw technique was mostly localized in three zones of the vertebral body, and patients with lower BMD had a higher risk of cement leakage and scattered cement distribution.

Three-dimensional computed tomography analysis and anteversion study after periacetabular osteotomy of pelvis in children

Three-dimensional computed tomography (CT) is the method of choice in understanding the morphological changes after periacetabular osteotomy in children. We studied different parameters and compared aspects of operated hip (OH) with non-operated hip (NOH) to define the maneuver that promotes normalization of the hip during repositioning of the acetabulum. A total of 22 patients with 25 OHs underwent CT control scans an average of 4 years after surgery. The patients, with a mean age of 6.8 years, had either Legg-Calvé-Perthes disease (12 cases) or dysplasia (10 cases).The measurements included the anterior and posterior coverage angles of the hip and version of the acetabulum on axial CT views. The 3D reconstructed images measured the inclination of the antero- and postero-lateral lips, the external rotation and the anterior inclination of the acetabulum. The mean anterior coverage angle was 27 degrees for OHs, 31 degrees for NOHs, and 12 degrees versus 10.3 degrees for the posterior coverage angle. Acetabular anteversion was 2 degrees for OHs (6.3 degrees in the dysplastic OHs) and 6 degrees for NOHs. The mean angle of inclination of the antero-lateral lip was 37 degrees for OHs, 47 degrees for NOHs, and the postero-lateral lip inclination was 56 degrees for OHs and 67 degrees for NOHs. Inferior 3D views showed a mean internal acetabular rotation of 1.5 degrees (4.8 degrees in the dysplastic OH), 3 degrees for NOH. The anterior acetabular inclination angle measured with lateral 3D views was 6 degrees for OHs, 11 degrees for NOHs. Our analysis demonstrated a mean anteversion of the acetabulum despite normalization of the anterior coverage of the hip, particularly in the dysplastic group, in which the osteotomized fragments had anteversion superior to NOH. The unexpected external rotation used to improve anterior coverage of a coax magna in Legg-Calvé-Perthes disease was responsible for the retroversion and the decrease of the posterior coverage.