Multiplanar Computed Tomography Research Articles

Analysis of Cochlear Morphology for Cochlear Implantation Using Three-Dimensional Reconstruction of Computed Tomography Images

Plain Language SummarySubjects suffering from sensorineural deafness have been able to regain partial hearing and speech understanding using cochlear implants. The frequency mapping of the cochlea is important for postoperative success. However, the frequency distribution of the human cochlea varies among individuals due to variations in cochlear length. Accurate measures of cochlear duct length for preoperatively defining this length are needed to maximize the effect of frequency mapping. This study analyzed the length and shape of the cochlea using three-dimensional reconstructions of the temporal bone based on computed tomography scans. Eight angular points (P0–P7) every 90° were selected from 0° to 630° from the center of the round window using the reconstructed cochlear canal images. The radius (R) and thickness (T) of the cochlear canal at each point were measured. Each point was theoretically positioned 90° relative to the origin starting from the center of the round window. Therefore, P0 and P7 are the angular points at 0° and 630°, respectively. The coiling ratio of the cochlea was measured using the ratios R4/R0, R5/R1, R6/R2, and R7/R3. The cochlear canal length (CoCL) was estimated using an equation based on the radius at each point. The mean CoCL from 0° to 630° was 31.5 mm, and the cochlear volume was 55.9 mm3. Based on the Greenwood and Erixon equations, our CoCL 360° and 630° measurements corresponded to frequencies of 982 (759–1,405) Hz and 312 (158–499) Hz. These are comparable with previously reported values.

Anatomical variations of the frontal sinus: A computed tomography-based study.

Background: The pneumatization of the frontal sinus is variable between individuals, including monozygotic twins. The volumetric anatomic variants of the frontal sinus are classified into aplasia, hypoplasia, medium-sized, and hyperplasia. We aimed to study the frontal sinus morphology in Omani patients using computed tomography (CT) evaluations. Methods: Retrospectively, 1220 frontal sinus CT scans from 610 patients investigated at Sultan Qaboos University Hospital, Oman, from January 2019 to December 2020 were reviewed. The frontal sinus morphology was classified according to the classification proposed by Guerram et al. The Chi-square test was used to determine the influence of sex. Results: With regard to the unilateral occurrence, the most prevalent frontal sinus category observed was medium-sized (13.3%), followed by hyperplasia (7.9%), hypoplasia (5.4%), and aplasia (2%) categories. Similarly, in bilateral occurrence, the most common frontal sinus category observed was medium-sized (53%), followed by hyperplasia (13.1%), hypoplasia (3.4%) and aplasia (2%) categories. Right and left frontal sinus aplasia were observed in 2.1% and 1.8% of cases, respectively. In terms of sex influence, the left unilateral ( p<0.01) and the bilateral hypoplasia ( p<0.05) were significantly higher in females. On the other hand, the left unilateral ( p<0.01) and the bilateral hyperplasia ( p<0.05) were higher in males. Conclusions: The baseline data of frontal sinus category frequencies reported in the present study is helpful in the diagnostic evaluation of sinusitis in the clinical setting. The preoperative recognition of frontal sinus types, particularly frontal sinus aplasia in multiplanar CT scans, is crucial to avoid unexpected complications while performing endoscopic sinus surgery.

Development and validation of a CT algorithm for the identification of nonperforated duodenal bulb ulcer

PurposeTo assess the value of multiplanar computed tomography (CT) in the diagnosis of nonperforated duodenal bulb ulcer (NPDBU). MethodWe retrospectively analyzed data from 135 patients with NPDBU (ulcer group) and 150 patients with a normal duodenal bulb (control group) who underwent contrast-enhanced abdominal CT and were diagnosed via upper endoscopy from January 2018 to February 2022. The clinical and CT features were compared between the two groups. Independent prognostic factors for diagnosing NPDBU were determined using binary logistic regression analysis. An external validation cohort to determine the model’s efficiency comprised 80 patients from another center. ResultsGastrointestinal bleeding was more frequent in patients with NPDBU than in those without (p < 0.001). No significant differences in age and sex were observed between the groups (all p > 0.05). The duodenal bulbar wall was significantly thicker in the ulcer group than in the control group, as determined using CT (p < 0.001). Irregular mucosal surface, layered enhancement, and blurred fat space around the duodenal bulb were more common in the ulcer group than in the control group (all p < 0.001). Binary logistic regression analysis revealed that gastrointestinal bleeding, wall thickness of ≥ 4.85 mm, irregular mucosal surface, and blurred peripheral fat space were the most significant variations associated with NPDBU, with an area under the curve (AUC) of 0.974. The external validation cohort had an AUC of 0.916. ConclusionsCareful multiplanar CT interpretation suggests the underlying presence of NPDBU and allows timely endoscopic verification and appropriate treatment.

Anatomical variations of frontal sinus pneumatization: A computed tomography-based study

Background: The pneumatization of the frontal sinus is variable between individuals, including monozygotic twins. The volumetric anatomic variants of the frontal sinus are classified into aplasia, hypoplasia, medium-sized, and hyperplasia. We aimed to study the frontal sinus morphology in Omani patients using computed tomography (CT) evaluations. Methods: Retrospectively, 1220 paranasal sinus CT scans from 610 patients investigated at Sultan Qaboos University Hospital, Oman, from January 2019 to December 2020 were reviewed. The frontal sinus morphology was classified according to the classification proposed by Guerram et al. The Chi-square test was used to determine the influence of sex. Results: With regard to the unilateral occurrence, the most prevalent frontal sinus category observed was medium-sized (13.3%), followed by hyperplasia (7.9%), hypoplasia (5.4%), and aplasia (2%) categories. Similarly, in bilateral occurrence, the most common frontal sinus category observed was medium-sized (53%), followed by hyperplasia (13.1%), hypoplasia (3.4%) and aplasia (2%) categories. Right and left frontal sinus aplasia were observed in 2.1% and 1.8% of cases, respectively. In terms of sex influence, the left unilateral (p&lt;0.01) and the bilateral hypoplasia (p&lt;0.05) were significantly higher in females. On the other hand, the left unilateral (p&lt;0.01) and the bilateral hyperplasia (p&lt;0.05) were higher in males. Conclusions: The baseline data of frontal sinus category frequencies reported in the present study is helpful in the diagnostic evaluation of sinusitis in the clinical setting. The preoperative recognition of frontal sinus types, particularly frontal sinus aplasia in multiplanar CT scans, is crucial to avoid unexpected complications while performing endoscopic sinus surgery.

A computed tomography study on the olfactory fossa in dried skulls.

The computed tomography (CT) study investigates the olfactory fossa (OF) morphometry and morphology. Fifty Greek adult dried skulls were macroscopically investigated for the detection of the OF morphological patterns and after a multiplanar CT reconstruction, the OF morphometry was accurately calculated using a digital ruler. Types I and II surface contour patterns were the most frequently identified (36 and 32%), followed by types III, IV, and V (16, 12, and 4%). Crista galli mean length, height, and width were 19.46 ± 2.34mm, 12.69 ± 2.7mm, and 5.18 ± 1.11mm. The OF mean maximum length was 22.29 ± 2.16mm on the right and 22.10 ± 2.44mm on the left side, and symmetry was detected. The OF median values of the maximum depth for its anterior, middle, and posterior third were 4.91mm, 4.72mm, and 2.78mm on the right and 4.55mm, 4.75mm, and 2.55mm on the left side. Symmetry was observed in any third of the OF. The OF median values of the surface maximum width for the anterior, middle, and posterior thirds were 9.29mm, 11.48mm, and 13.07mm. A significant gradual increase of the OF surface maximum width was detected in the anteroposterior direction in the total sample (p < 0.001), with the highest value (23.12mm) in the posterior third. A significant (p < 0.001) very strong (rs = -0.798) and a moderate (rs = -0.524) negative linear correlation in the OF anterior and middle third were, respectively, identified between its maximum depth and width. No gender impact was identified. The study helps to familiarize with the calculation of the OF dimensions and simplifies the understanding of its complex anatomy, to reach successful surgical planning and minimize perioperative complications.

Detection of cervical spine trauma: Are 3-dimensional reconstructed images as accurate as multiplanar computer tomography?

IntroductionThis study was conducted to assess the diagnostic accuracy of three-dimensional computed tomography (3D-CT) in detection of cervical spine injuries in symptomatic post-trauma patients using multiplanar computed tomography (MP-CT) as reference standard. ApproachThis cross-sectional study was conducted at Aga Khan University from July 2016 to January 2017. Patients were included using a non-probability, consecutive sampling. MP-CT and 3D- CT images were obtained and evaluated by a senior radiologist to identify cervical spine injuries. Results205 patients were included in the study. For fractures, 3D-CT images had sensitivity of 71%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 96.8% and diagnostic accuracy of 97%. For dislocations, 3D-CT reported sensitivity of 83.34%, specificity of 100%, positive predictive value of 100% and negative predictive value of 99.5% and diagnostic accuracy of 99.5%. Conclusion3D-CT has good diagnostic accuracy for injuries of the cervical spine but must be reviewed simultaneously with multiplanar CT images.

CT of the medial clavicular epiphysis for forensic age estimation: hands up?

PurposeThe aim of this study was to assess the impact of arm position in computed tomography (CT) of the clavicle performed for forensic age estimation on clavicular position, image noise, and radiation dose.Methods and materialsForty-seven CT scans of the medial clavicular epiphysis performed for forensic age estimation were conducted with either hands and arms held upwards (CTHU, 28 persons) or positioned at the body (CTHD, 19 persons). Presets were identical for both positions (70 mAs/140 kVp; Brilliance iCT, Philips). Each CT scan was reconstructed with an iterative algorithm (i-Dose 4) and evaluated at the middle of the sternoclavicular joint. Clavicular angle was measured on a.p. topograms in relation to a horizontal line. Quantitative image noise was measured in air at the level of medial clavicular epiphysis. Effective dose and scan length were recorded.ResultsHands-up position compared with hands-down position resulted in a lower lateral body diameter (CTHU 41.1 ± 3.6 cm vs. CTHD 44.6 ± 3.1 cm; P = 0.03), a reduced quantitative image noise (CTHU: 39.5 ± 9.2; CTHD: 46.2 ± 8.3; P = 0.02), and lower CTDIvol (5.1 ± 1.4 mGy vs. 6.7 ± 1.8 mGy; P = 0.001). Scan length was longer in patients examined with hands up (HU: 8.5 ± 3.4 cm; HD: 6.2 ± 2.1 cm; P = 0.006). Mean effective dose for CTHU was 0.79 ± 0.32 mSv compared with 0.95 ± 0.38 mSv in CTHD (P = 0.12). Clavicular angle was 17° ± 6° in patients with hands down and 32° ± 7° in patients with hands up (P < 0.001).ConclusionBy elevated arm positioning, the image quality of clavicular CT scans can be improved while maintaining radiation dose compared with hands down. Clavicular position differs according to the hand position. Thus, positioning patients with elevated hands is advisable for forensic clavicular CT examinations, but multiplanar CT reconstructions should be adjusted to clavicular position and scan length should be reduced to a minimum.

Computed Tomographic Assessment of Age- and Gender-Specific Sagittal Lumbopelvic Alignment in a Japanese Population.

Introduction Previous studies have reported differences in lumbopelvic alignment between standing and supine positions. Computed tomography (CT) images taken in the supine position are often used for clinical studies in addition to standing radiographs, although not frequently. Our study aims to clarify normative values of CT-evaluated lumbopelvic parameters and the characteristics of age- and gender-related lumbopelvic alignment in the supine position. Methods Patients undergoing CT scans of abdominal or lumbar regions for reasons other than low back disorders were included (n=581). Sagittal multiplanar reconstruction CT images were obtained, and lumbar lordosis (LL), L5-S1 angle, and sacral slope (SS) were measured. Mean values of the parameters in patients aged 59 years and under, 60-69, 70-79, and 80 and over, and in males and females, were calculated. Age- and gender-related differences in these parameters were statistically analyzed. Results Among the four age groups, patients 80 years and over showed significantly lower LL and SS than patients aged 70-79. Females 80 years and over showed significantly lower LL and SS than all other age groups, but those in males did not. The comparison between males and females showed no significant differences in LL and SS; however, the L5-S1 angle was significantly higher in males than in females. In patients 80 years and over, females showed significantly lower LL and SS than in males. Conclusions This study provides normative CT-evaluated lumbopelvic parameters, such as LL, L5-S1 angle, and SS, which will be utilized for comparisons in future studies. The present study first revealed that pelvic retroversion and lumbar kyphosis occur in elderly females in the supine position, which raised a possibility that age-related decrease of LL and SS in females occurs at an older age in the supine position than in the standing position.

Use of tracheobronchial tree 3-dimensional printed model: does it improve trainees\u2019 understanding of segmentation anatomy? A prospective study

BackgroundThis prospective study investigated whether the use of 3D-printed model facilitates novice learning of radiology anatomy on multiplanar computed tomography (CT) when compared to traditional 2D-based learning tools. Specifically, whether the use of a 3D printed model improved interpretation of multiplanar CT tracheobronchial anatomy.MethodsThirty-one medical students (10F, 21 M) from years one to three were recruited, matched for gender and level of training and randomized to 2D or 3D group. Students underwent 20-min self-study session using 2D-printed image or 3D-printed model of the tracheobronchial tree. Immediately after, students answered 10 multiple-choice questions (Test 1) to identify tracheobronchial tree branches on multiplanar CT images. Two weeks later, identical test (Test 2) was used to assess retention of information. Mean scores of 2D and 3D groups were calculated. Student’s t test was used to compare mean differences in tests scores and analysis of variance (ANOVA) was used to assess the interaction of gender, CT imaging plane and time on test scores between the two groups.ResultsFor test 1, 2D group had higher mean score than 3D group although not statistically significant (7.69 and 7.43, p = 0.39). Mean scores for Test 2 were significantly lower than for Test 1 (7 and 7.57, p = 0.03) with mean score decline for 2D group (Test 1 = 7.69, Test 2 = 6.63, p = 0.03), and similar score for 3D group (Test 1 and 2 = 7.43). There was no statistically significant interaction of gender and test score over time. Significant interaction between group and time of test was found for axial CT images but not for coronal images.ConclusionsUse of a 3D-printed model of the tracheobronchial anatomy had no immediate advantage over traditional 2D-printed images for learning CT anatomy. However, use of a 3D model improved students’ ability to retain learned information, irrespective of gender.

Benefits of the multiplanar and volumetric analyses of pancreatic cancer using computed tomography.

Although pancreatic cancer tumors are irregularly shaped in terms of their three-dimensional (3D) structure, when T staging by imaging results, generally only the axial plane is used to measure the largest tumor diameter. We investigated the size of pancreatic cancer tumors using multi-plane and 3D reconstructed computed tomography (CT) images and investigated their clinical usefulness. Patients who underwent surgery for pancreatic adenocarcinoma were included. We measured the largest diameter of each pancreatic tumor in the axial, coronal, and sagittal planes of CT images. In addition, maximal diameter and cancer volume were measured from 3D images that were constructed using a semi-automated software system. Final data were compared with pathologic examination and the effect of each value on prognosis was analyzed. A total of 183 patients were analyzed. The maximal diameters measured on the axial, coronal, and sagittal planes were 2.9 ± 1.1, 3.2 ± 0.9, and 3.2 ± 1.0 cm, respectively, which were significantly smaller than pathologic results (3.4 ± 1.4 cm, all p<0.05 by paired t-test). The longest diameter among them (3.4 ± 1.1 cm) was nearly similar to the pathologic diameter. Cancer volume measured on 3D images demonstrated a higher area under the receptor operating characteristic curve [0.714, (95% confidence interval: 0.640–0.788)] for predicting early death compared to any unidimensional CT diameters measured. The longest pancreatic tumor diameter measured on multiplanar CT images was most accurate when compared to its corresponding pathologic diameter. Tumor volume had a stronger correlation with overall survival than tumor diameter.

A series of post-traumatic midline epidural hematoma and review of the literature.

Supratentorial midline epidural hematoma is rare but challenging in diagnosis and management. Indication for surgery can arise even following hospital admission. Being familiar to the presentation and watching out for direct and indirect signs on axial computed tomography (CT) such as suture diastasis or fracture traversing midline are essential to plan multi-planar CT enabling exact diagnosis including form and mass effect of hematoma. Nine patients with midline epidural hematoma including two pediatric patients underwent surgery between 2013 and 2018. Pre-operative and post-operative patient status, radiological features, and surgical technique were analyzed. Four patients had deteriorating consciousness levels and two patients had paraparesis. All had fractures traversing midline and epidural hematomas with significant mass effect. They were operated through separated craniotomies around the midline and midline bone strip was used for dural tenting and as support for natural closure of bone flaps. No post-operative complications were developed. All patients were discharged with Glasgow Outcome Score of 5. Because of the rarity of the lesion and small number of patients, definitive conclusions may be misleading but we think that, in experienced hands, midline epidural hematomas can safely be operated on and, preservation of midline bone strip pro-vides easier bleeding control.

Concha Bullosa Affects Baseline and Postoperative Quality-of-Life Measures in Surgically Managed Chronic Rhinosinusitis.

Background Concha bullosa (CB) is a prevalent anatomic variant and frequent surgical target in endoscopic sinus surgery (ESS). However, whether CB impacts quality-of-life (QOL) in chronic rhinosinusitis (CRS) is not well established. The purpose of this study was to investigate baseline and post-ESS QOL differences in patients with medically recalcitrant CRS with and without CB. Methods Demographic and surgical characteristics, baseline and postoperative 22-item Sino-Nasal Outcome Test (SNOT-22) scores for 137 patients with CRS who underwent primary ESS at our institution were recorded. Computed tomography (CT) scans were reviewed for Lund–Mackay score and presence of CB. Multiplanar CT was used to measure CB dimensions and estimate volume. Multivariable analysis was performed to identify differences in SNOT-22 overall and symptom-domain scores between patients with upper quartile (≥0.8 mL) CB and without CB. Results CB was found in 37% of patients with mean volume of 0.67 mL. There were no significant differences in distribution of clinicodemographic variables by large CB status. At baseline, large CB was associated with higher SNOT-22 extranasal-rhinologic domain score (9.8 vs 6.0, P &lt; .01). Following ESS, patients with large CB reported greater improvement in SNOT-22 extranasal-rhinologic domain score (multivariable mean absolute improvement 3.8, P = .01; relative 56% vs 30%). Conclusion Patients with medically recalcitrant CRS and concomitant large CB have higher SNOT-22 extranasal-rhinologic domain scores at baseline, but also report greater intradomain improvement exceeding the subdomain’s mean clinically important difference. To our knowledge, this is the first demonstration that CB has a clinically significant impact on QOL in CRS, and surgical intervention may be helpful to address these symptoms.

P35. Transforaminal full-endoscopic lumbar discectomy at the L5-S1 disc level: anatomical considerations and operability

BACKGROUND CONTEXT Transforaminal full-endoscopic lumbar discectomy (TELD) is a minimally invasive procedure for the surgical treatment of lumbar disc herniation (LDH). It can be performed under local anesthesia and requires a skin incision of only 8 mm, with minimal disruption of the spinal structures including ligaments and muscles. However, performing TELD for the lower lumbar spine is associated with some anatomical problems, such as interference with the iliac crest. This study sought to assess the operability of TELD at the L5-S1 disc level. PURPOSE The purpose of this study is to assess a three-dimensional relationship between the trajectory of TELD and the iliac crest, and the operability of TELD at the L5-S1 disc level compared with the L4-L5 disc level using CT images. STUDY DESIGN/SETTING This is a retrospective study using 323 multiplanar abdominal computed tomography (CT) scans. PATIENT SAMPLE We retrospectively reviewed multiplanar abdominal CT scans of 323 consecutive patients (203 male and 120 female) in our hospital from April 2009 to March 2013. The mean age was 66.5 (range 15-89) years old. OUTCOME MEASURES The operability of the TELD at the L5-S1 disc level was the outcome measure. METHODS We defined the tangent line in the iliac crest and the superior articular process of the caudal spine as the trajectory line of TELD, and evaluated the maximum inclination angle of the trajectory of the TELD (α angle) at the L4–L5 and the L5-S1 disc levels. Assuming the use of an oblique viewing endoscope at 25°, we defined α angle≥65° as the operability of TELD. RESULTS (1) The relationship between the iliac crest and disc level: The trajectory of the TELD interfered with the iliac crest at L4-L5 in 40.2% (right) and 54.5% (left) of the subjects, and at L5-S1 in 99.7% and 100% of the subjects. (2) The maximum inclination angle of the trajectory of TELD: the α angles were 84.3° and 82.3° at the L4-L5, and 56.8° and 55.2° at L5-S1. (3) Operability of TELD: At L4-L5, TELD could be performed in 94.4% and 90.4% of the subjects. In contrast, at L5-S1 the procedure could be performed in 24.1% and 19.2% of the subjects (male: 15.8% and 10.8%, female: 38.3% and 33.3%). CONCLUSIONS From the results of this study, the trajectory of TELD can be limited by the surrounding anatomical structure. The maximum inclination angle indicates that TELD for the central type of LDH at the L5-S1 disc level is more technically demanding than TELD at the L4-L5 disc level because of the interference of the iliac crest. However, in the clinical setting, such anatomical particularities can be overcome by using a hand-down technique with the possible addition of a foraminoplasty when we perform TELD at the L5-S1 disc level. Because the maximum inclination angle is defined by the iliac crest and ventrolateral aspect of the superior articular process, it makes sense that we remove the superior articular process partially. After widening the neural foramen after foraminoplasty, the working cannula could easily and safely pass through the foramen without touching the exiting nerve root, and be close to the herniated disc. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

In Vitro Evaluation of the Gore Viabahn Balloon-Expandable Stent-Graft for Fenestrated Endovascular Aortic Repair

Purpose: To evaluate the safety and integrity of a new stent-graft as a potential bridging device in fenestrated stent-grafts using an in vitro fenestrated model. Materials and Methods: Polyester test sheets with ten 6-mm- or 8-mm-diameter fenestrations were used to simulate a fenestrated main body endoprosthesis. In total, 50 Viabahn balloon-expandable (VBX) stent-grafts of varying lengths (29 and 39 mm) and diameters (6, 7, and 8 mm) were implanted in the fitting fenestrations. After release, the 6- and 7-mm-diameter stent-grafts were flared with a 10×20-mm angioplasty balloon; a 12×20-mm balloon was used in the 8-mm-diameter devices. Safety of the devices was defined as absence of fractures detected on radiography or computed tomography (CT), as well as material failure detected by microscopy and water permeability testing. The forces (in Newtons, N) needed for perpendicular dislocation (pullout force) and axial dislocation (shear stress force) were also evaluated. Results: Forty VBX stent-grafts were subjected to digital radiographic imaging and multiplanar CT. None showed any stent fracture. Subsequent microscopy indicated no damage to the fabric or separation of the graft after flaring. Ten VBX stent-grafts underwent water permeability testing after flaring; no water passed through the graft wall during a 10-minute period under an intraluminal pressure at 120 mm Hg. Testing of 25 VBX stent-grafts revealed initial pullout forces between 11.3 and 31 N. Shear stress tests showed that the average force needed to dislocate the stent-grafts by 50% of their diameter ranged between 5.75 and 6.91 N (mean 6.1±0.5 N) for the 6-mm stents and between 3.31 and 5.4 N (mean 4.4±0.8) for the 8-mm stents. Conclusion: This preliminary study demonstrated the applicability of the VBX as a bridging stent-graft in a simulated fenestration model. A comparison with other stent-grafts and clinical assessment are required.

Preoperative 3D CT Planning for Cortical Bone Trajectory Screws: A Retrospective Radiological Cohort Study

Pedicle screw instrumentation is a standard procedure in lumbar spinal fusion. The cortical bone trajectory (CBT) screw is an alternative technique, less invasive but harder to perform. The identification of the entry point and the appropriate direction can be tricky especially to the surgeons just at the beginning. Therefore, the aim of this study is to evaluate the reliability of preoperative computed tomography (CT) planning in the CBT screw placement. We retrospectively evaluated 82 patients who underwent a single-level posterior lumbar arthrodesis with CBT screws. The correct entry point and the best trajectory were identified on a 3-dimensional (3D) multiplanar reconstruction CT view. The concordance between achieved and planned trajectories was assessed on a postoperative CT. A total of 328 screws was positioned. The average entry point distance from the target was 1.1 mm (standard deviation, ±0.15 mm). In 301 screws (91.8%), the obtained trajectory differed no more than 2° from the planned one. No screws misplaced or new neurological deficit was recorded. The CBT screw placement is a great alternative to the pedicle screw. Accurate preoperative 3D planning is useful to predict the entry point and the direction with accuracy similar to navigation systems, avoiding its costs and technical difficulties. The 3D CT planning is helpful in the customization of spine surgery, and the results underline the radiological reliability of this technique.

Applicability of color-coded computed tomography images in lung volume reduction surgery planning.

Adequate patient selection is the key to successful lung volume reduction in patients with pulmonary emphysema. Computed tomography (CT) enables a reliable detection of pulmonary emphysema and allows an accurate quantification of the severity. Our goal was to investigate the usefulness and reliability of color-coded (CC) CT images in classification of emphysema and preoperative lung volume reduction planning. Fifty patients undergoing lung volume reduction surgery at our institution between September 2015 and February 2016 were retrospectively investigated. Three readers visually assessed the amount and distribution patterns of pulmonary emphysema on axial, multi-planar and CC CT images using the Goddard scoring system and a surgically oriented grading system (bilateral markedly heterogenous, bilateral intermediately heterogenous, bilateral homogenous and unilateral heterogenous emphysema). Observer dependency was investigated by using Fleiss' kappa (κ) and the intraclass correlation coefficient (ICC). Results were compared to quantitative results from densitometry measurements and lung perfusion scintigraphy by using Spearman correlation. Recommendations for lung volume reduction sites based on emphysema amount and distribution of all readers were compared to removal sites from the surgical reports. Inter-rater agreement for emphysema distribution rating was substantial for CC images (κ=0.70; 95% CI, 0.64-0.80) and significantly better compared to axial and multiplanar images (P≤0.001). The inter-rater agreement for recommended segment removal was moderate for CC images (κ=0.56; 95% CI, 0.49-0.63) and significantly better compared to axial and multiplanar images (P<0.001). Visual emphysema rating correlated significantly with measurements from densitometry and perfusion scintigraphy in the upper and lower lung zones in all image types. CC CT images allow a precise, less observer-dependent evaluation of distribution of pulmonary emphysema and resection recommendation compared to axial and multiplanar CT images and might therefore be useful in lung volume resection surgery planning.

Anatomical variations of anterior ethmoidal artery at the ethmoidal roof and anterior skull base in Asians.

The variations of the anterior ethmoidal artery (AEA) in different populations should be recognized by surgeons to prevent unwarranted complications during surgery. The aim of this study was to assess the anatomical variations of AEA in Asian population. A cross-sectional study of 252 AEA identified by computed tomography (CT) of the paranasal sinuses. The multiplanar CT images were acquired from SOMATOM® Definition AS+ and reconstructed to axial, coronal and sagittal view at 1mm slice thickness. 42.5% of AEA was within skull base (grade I), 20.2% at skull base (grade II) and 37.3% coursed freely below skull base (grade III). The prevalence of supraorbital ethmoid cell (SOEC) and suprabullar cell (SBC) was 29.8% and 48.0%. The position of AEA at skull base has significant association with SOEC (p < 0.001), but not with SBC (p = 0.268). Type I Keros was 42.1% and Type 11 Keros was 57.9%. When lateral lamella's height is longer, the probability increases for AEA to course freely within the ethmoid sinus (p = 0.016). The mean distance of AEA from skull base was 1.93 ± 2.03mm, orbital floor 21.91 ± 2.47mm and nasal floor 49.01 ± 3.53mm. The position of AEA at skull base depends on the presence of SOEC and length of lateral lamella, but not with SBC. When compared to European population, the mean distance between AEA and nasal floor is shorter in Asians.

The female geriatric proximal humeral fracture: protagonist for straight antegrade nailing?

IntroductionStraight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail’s proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail’s proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture.Materials and MethodsA total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75–102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail’s ideal entry point, “critical point” (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails.ResultsOverall, 35.6% (108/303) of all proximal humeri were found to be “critical types” (CD <8 mm) as to the recommended minimal proximal reaming diameter of 10 mm of straight antegrade nails currently in use. Moreover, 43.2% (131/303) of the humeri were considered “critical types” with regard to the alternatively used larger proximal reaming diameter of 11.5 mm. Mean CD was 9.0 ± 1.7 mm (range 3.5–13.5 mm) and did not correlate with age (r = −0.04, P = 0.54). No significant differences in CD and rate of “critical types” were found between left and right humeri as well as between females aged between 75 and 84 years (n = 151) and females aged 85 and older (n = 152).ConclusionsMore than a third of proximal humeri of geriatric females are “critical types” as to SAHN and may, therefore, be at risk for procedure-related complications, such as rotator cuff violation, fixation failure, and potential malreduction. In view of this finding, we recommend to routinely analyze multiplanar CT reformations of the uninjured contralateral side prior to surgery to improve selection of patients for SAHN and to minimize foreseeable complications. For “critical type” humeri, an alternative surgical procedure should be considered.

Anatomical considerations of the iliac crest on percutaneous endoscopic discectomy using a transforaminal approach

Background ContextPercutaneous endoscopic discectomy is a minimally invasive procedure for the surgical treatment of lumbar disc herniation (LDH). It can be performed under local anesthesia and requires a skin incision of only 8 mm, with minimal disruption of the spinal structures including ligaments and muscles. However, performing percutaneous endoscopic discectomy with a transforaminal approach (TF-PED) for the lower lumbar spine is associated with some anatomical problems, such as interference from the iliac crest. This study sought to assess the operability of TF-PED for the lower lumbar spine. PurposeThe purpose of this study was to assess a three-dimensional relationship between the trajectory of TF-PED and the iliac crest, and the operability of TF-PED at the lower lumbar disc levels (L4–L5 and L5–S1) using CT images. Study DesignThis is a retrospective study using 323 multiplanar abdominal computed tomography (CT) scans. Patient SampleWe retrospectively reviewed contrast-enhanced multiplanar abdominal CT scans of 323 consecutive patients (203 male and 120 female) in our hospital from April 2009 to March 2013. The mean age was 66.5 (range 15–89) years old. Outcome MeasuresThe operability of the TF-PED was the outcome measure. Materials and MethodsWe defined the tangent line in the iliac crest and the superior articular process of the caudal spine as the trajectory line of TF-PED, and evaluated the maximum inclination angle of the trajectory of the TF-PED (α angle) at the L4–L5 and the L5–S1 disc levels. Assuming the use of an oblique viewing endoscope at 25°, we defined α angle≥65° as the operability of TF-PED. Results(1) Relationship between iliac crest and disc level: The trajectory of the TF-PED interfered with the iliac crest at L4–L5 in 40.2% (right) and 54.5% (left) of the subjects, and at L5–S1 in 99.7% and 100% of the subjects. (2) The maximum inclination angle of the trajectory of TF-PED: the α angles were 84.3° and 82.3° at the L4–L5, and 56.8° and 55.2° at L5–S1. (3) Laterality of the α angle: At both disc levels, the mean age of the subjects with a laterality of ≥10° was significantly higher than that of subjects with a laterality of <10°. (4) Operability of TF-PED: At L4–L5, TF-PED could be performed in 94.4% and 90.4% of the subjects. In contrast, at L5–S1 the procedure could be performed in 24.1% and 19.2% of the subjects (male: 15.8% and 10.8%, female: 38.3% and 33.3%). ConclusionsFrom the results of this study, the trajectory of TF-PED can be limited by the surrounding anatomical structures. The maximum inclination angle indicated that treatment for the central type of LDH at the L5–S1 disc level was considered more difficult than that at the L4–L5 disc level because of the iliac crest. In the clinical setting, such anatomical particularities can be overcome by using a more perpendicular approach (hand-down technique) with the possible addition of a foraminoplasty. Moreover, we found that we must consider the laterality of the trajectory of TF-PED in terms of the patients' age or sex.

Accuracy of minimally invasive percutaneous thoracolumbar pedicle screws using 2D fluoroscopy: a retrospective review through 3D CT analysis.

In the literature, there is a large variation in the reported misplacement rates of pedicle screws. The use of minimally invasive surgical techniques is increasing and as such there has only been a small amount of data to look at the misplacement rate of percutaneously inserted thoracic and lumbar pedicle screws. A retrospective analysis of post-operative computed tomography (CT) scans were performed on 108 patients who underwent minimally invasive percutaneously inserted thoracic and lumbar pedicle screws by a single surgeon. Analysis of the screw trajectory using strict guidelines was performed using multiplanar reconstruction CT scan data to determine the accuracy of the pedicle screws. A total of 614 screws were inserted in vertebral levels T2 to S1. Twenty-five (4.07%) screws were considered misplaced having breached the pedicular cortex. Thoracic pedicle screws had a statistically higher misplacement rate than lumbar pedicle screws (14.67% vs. 2.60% respectively, P<0.001). A single screw required replacement (0.16%) and there were no permanent neurological deficits. The misplacement rates were lower than those reported for open screw placement and equivalent to 3D CT navigated misplacement rates. Percutaneously inserted pedicle screws using 2D fluoroscopy offers a safe and accurate option for spinal stabilisation with an extremely low misplacement rate and morbidity. Overall, the low misplacement rates were equivalent and in most cases lower compared to open and computer assisted navigation techniques. However, we would recommend that given a misplacement rate of 14.67% for thoracic pedicle screws that computer assisted navigation may be able to offer further improvements in accuracy.