Sagittal CT Reconstructions Research Articles

Anatomical Evaluation of the Atlas and Analysis of Accuracy for Freehand C1 Screw Placement

Objective: Atlanto-axial fusion surgery for instability is a recognized method. However, the complex anatomical structures of the atlas and axis make freehand C1 screw placement technically challenging. This study investigated the accuracy and safety of C1 screw placement without fluoroscopic or other guidance.Methods: A retrospective analysis of radiological data was performed on patients who underwent C1 instrumentation between April 2019 and January 2023, with all procedures performed by a spine surgeon with 4 years of experience. Computed tomography was used to evaluate cortical breaches during C1 screw placement. Breach severity was categorized based on the percentage of screw diameter beyond the cortical edge. Morphometric measurements of 30 healthy individuals and 22 patients who underwent surgery were obtained from preoperative CT scans of the bilateral pedicles at the C1 level. Coronal, axial, and sagittal CT reconstructions were examined to ascertain the distance from the screw entry point to the midpoint of the C1 posterior tubercle, diameter of the central canal of the atlas, screw convergence angle, height of the C1 posterior arch at the screw entry point, and width of the canal. Results: The surgeon placed 43 C1 screws in 22 consecutive patients. Seven (16%) breaches were identified, all of which were medial C1 screws. The breaches were classified as grades I, III, and IV in 4 (57%), 2 (29%), and 1 (14%) cases, respectively. No clinical complications arose owing to the breaches.Conclusion: The freehand technique for C1 screw placement without guidance yielded accurate and safe results. However, a preoperative morphometric assessment and careful familiarization with the unique anatomy are imperative for improving screw placement precision.

A new “de-tension”-guided surgical strategy for multilevel ossification of posterior longitudinal ligament in thoracic spine: a prospective observational study with at least 3-year follow-up

BACKGROUND CONTEXTMultilevel ossification of the posterior longitudinal ligament in thoracic spine (mT-OPLL) is a rare but clinically significant spinal condition. Various surgical methods have been developed to address this disease. However, the outcomes are commonly unfavorable, and no standard surgical strategy has been established. To solve this problem, we introduced a new surgical strategy based on an innovative decompression concept, namely “de-tension.” PURPOSEThis study aimed to investigate the safety and efficacy of this new treatment, and to establish an improved surgical strategy. STUDY DESIGNA prospective observational study with at least 3 years of follow-up. PATIENT SAMPLEFifty-one patients with consecutive mT-OPLL who were treated between August-2012 and June-2018 were enrolled in this study. OUTCOME MEASURESA modified Japanese Orthopedic Association (mJOA) scale assessing thoracic spine, recovery rate (RR), and surgical complications. METHODSAll patients underwent 1-stage thoracic posterior laminectomy, selective OPLL resection, and spinal column shortening with/without reduction of kyphosis (dekyphosis). Initially, we recommended that when thoracic kyphosis of T1-T12 in sagittal reconstruction CT (TK) was less than 20°, no dekyphosis should be performed; when this angle was greater than 20°, dekyphosis could be conducted. Patients’ demographic data, radiological findings, and intra/postoperative complications were recorded and analyzed. Neurological status was evaluated with mJOA score and RR. The correlation of preoperative TK or kyphosis angle in fusion area (FSK) with postoperative dekyphosis angle and spinal column shortening distance (SD) were respectively evaluated by Pearson correlation analysis. RESULTSCerebrospinal fluid leakage (58.8%) and neurological deterioration (15.7%) were the most common complications. Average mJOA score was improved from preoperative 4.0±2.1 to 8.9±2.4 at the last follow-up, and the mean RR was 71.3±33.7%. There was no correlation between preoperative TK and SD (p=.56) or between preoperative FSK and SD (p=.21), but dekyphosis angle was significantly correlated with TK (r=0.504, p<.01) and FSK (r=0.5734, p<.01). TK of 24.6° and FSK of 23.0° were determined as the critical angles for dekyphosis, and a modified surgical strategy was formulated. CONCLUSIONSThis new strategy provided a novel solution for mT-OPLL, and was proved to be safe and effective during long-term follow-up. Further rigorously designed large-scale prospective studies are needed to validate our findings.

Asymmetry of the C2 pars interarticularis: a clinical anatomical study with relevance to screw placement.

Potential asymmetries of the C2 posterior elements pose a problem for the spine surgeon seeking to make the best choice for spinal stabilization while reducing morbidity. A digital caliper was used to measure the pars interarticularis height and length on left and right sides of 25 adult C2 vertebrae. The pars interarticularis was defined as the bone between the posterior most aspect of the superior articular process and the anterior most aspect of the inferior articular process of C2. Also, the C2 vertebrae from 49 patients were scanned by CT. Parasagittal images were reviewed and using the same definitions as were used for the skeletal specimens, the length and the height of the C2 pars interarticularis from both the left and right sides were measured using CT. The image slices were acquired at 3mm intervals. The pars interarticularis height was determined on sagittal CT reconstruction, while the pars interarticularis length was calculated on the basis of the axial images. The lengths and the heights of the left and right pars interarticularis were compared using CTs of patients and skeletal specimens. No significant differences were found in the length and height measurements of the CT images on both sides. However, in the skeletal specimens, the left and right pars interarticularis did not differ significantly in length but differed significantly in height (p = 0.003). The mean height of the left pars interarticularis was approximately two times larger than the right in the skeletal specimens. Absolute differences were calculated between the side with the greater length and height and the side with the lesser length and height irrespective of their left-right orientations. For CT measurements, most differences in length and height between the greater pars interarticularis and lesser pars interarticularis occurred between 0 and 1mm with each successive disparity interval yielding lower numbers. Skeletal measurements revealed a similar length disparity distribution to the CT measurements. However, height measurements in the skeletal specimens varied widely. Eight pars interarticularis specimens demonstrated a height difference between 0 and 1mm. No dry bone pars interarticularis specimens demonstrated a height difference between 1 and 2mm. The pars interarticularis of nine specimens demonstrated a height difference between 2 and 3mm. Two demonstrated a height difference between 3 and 4mm. Four demonstrated a height difference between 4 and 5mm and two demonstrated a height difference greater than 5mm. The greater pars interarticularis lengths and heights were combined and compared to their lesser counterparts on CT and skeletal measurements. In all measurements of this type, significant differences were found in the pars interarticularis length and height, whether measured through CT or via digital calipers. Asymmetry between the left and right C2 pars interarticularis as shown in the present study can alter surgical planning. Therefore, knowledge of this anatomical finding might be useful to spine surgeons.

Utility of the decubitus or the supine rather than the extension lateral radiograph in evaluating lumbar segmental instability.

To determine the superiority of decubitus and supine radiographs for the reduction of olisthesis instead of the extension radiograph, and the inconsistency of the CT scout view, 3D-reconstruction and MR image in evaluating segmental instability. A cohort of 154 low-grade lumbar degenerative spondylolisthesis patients with the average age of (60.9 ± 8.6) years were enrolled. Slip percentage was measured on the flexion, upright and extension radiographs, the decubitus lateral radiograph, CT scout view, the supine median sagittal 3D-reconstruction and MR image. The translational range of motion was calculated, and segmental instability was defined as translational motion ≥ 8%. The flexion radiograph showed higher slip percentage than upright radiograph (p < 0.001). The slip percentage of the MR image was lower than CT scout view (p = 0.003) and CT sagittal radiograph (p = 0.001) on the basis of statistical differences among three groups (p = 0.002). The slip percentage of the CT scout view, decubitus radiograph, and extension radiograph was statistically different (p = 0.01). The CT scout view and sagittal reconstruction had lower slip percentage than the extension radiograph (p = 0.042; p = 0.003, respectively). Both the flexion-supine and flexion-decubitus modality had larger translational motion than the flexion-extension modality (p = 0.007; p < 0.001, respectively). Many modalities and techniques are used to show the vertebral displacement and its possible change and any cane used in the daily practice. In this study, supine and decubitus lateral radiography have larger reduction of olisthesis than the extension radiograph. The flexion radiograph coupled with a supine or decubitus radiograph reveals greater mobility than the flexion-extension modality.

Morphometry of the Entire Internal Carotid Artery on CT Angiography.

Background and Objectives: Knowledge of the internal carotid artery’s (ICA) morphometric features is influential in outlining surgical and minimally invasive procedures in the neurovascular field. Many studies have shown divisive numbers regarding the ICA’s caliber, with the measuring point of the artery sometimes differing. This study presents ICA dimensions based on computed tomography angiography in each of its seven segments as per Bouthillier’s classification, correlating vascular dimensions with anthropometric parameters. Materials and Methods: A thorough CT angiography analysis was performed on 70 patients with internal carotid vessels unaffected by atherosclerotic disease. The extracranial part of the ICA was measured in four locations—carotid bulb, post-bulbar dilation, at its cervical midpoint, and below its entrance into the carotid foramen. Single landmarks were used for measurements in the intracranial segments. ICA length was assessed in the neck region and also in the cranial cavity. Craniometric measurements were performed on sagittal and coronal CT reconstructions. Patient height was taken into consideration. Results: The largest ICA portion is near its origin in the carotid sinus area (7.59 ± 1.00 mm), with a steep decline in caliber following its extracranial course. Distal ICA presented values somewhat similar to its proximal intracranial segment diameters (4.67 ± 0.47 mm). Dimensions of the ICA in the intracranial segments start from a value of 4.53 ± 0.47 mm and decrease by approximately 40% when reaching the origin of the middle cerebral artery (2.71 ± 0.37 mm), showing a marked decrease in caliber after the emergence of the most critical collateral artery, the ophthalmic branch. The length of the ICA varies between genders, with the male ICA being about 10 mm longer in total length than female ICA; this difference is also correlated with patient height and skull dimensions. Conclusions: Both intra- and extracranial ICA have variable dimensions and length related to gender and anthropometric parameters, with no significant differences obtained concerning side or age.

A Retrospective Study on the Morphology of Posterior Malleolar Fractures Based on a CT Scan: Whether We Ignore the Importance of Fracture Height.

Objective The aim of this study was to investigate the respective correlation between the height (H) of a posterior malleolar fracture (PMF) and the involved area (S) of an articular surface and the presence of “die-punch.” Methods Patients with closed posterior malleolar fractures admitted to our hospital from January 2015 to December 2017 were selected, with complete X-ray and 3D reconstruction CT imaging data. The gender, age, injured side, and surgical fixation methods of the patients were recorded. A preoperative ankle CT scan was performed, and the images were viewed through the PACS (Picture Archiving and Communication Systems). Simultaneously, the involved joint surface area (S) by the posterior malleolar fracture was measured, as well as the proportion of the fracture area to the total ankle joint area. On the sagittal reconstruction CT images, the height (H) of the posterior malleolar fracture was measured to compare the correlation between the height of the fracture and the area of the fracture, as well as the area ratio. Besides, according to the presence or absence of “die-punch,” patients were divided into two groups: A and B. And each group was further divided into three subgroups according to age (16-39 years old, 40-59 years old, and ≥60 years old). The statistical differences in the height of fracture between the subgroups were compared. Results A total of 48 patients, aged 16-82 years, with an average age of 48.9 years, were included in this study, including 13 males and 35 females. There were 20 cases of left ankle injury and 28 cases of right ankle injury. The average height of the posterior malleolar fractures was 18.19 mm, the average area of the fracture was 202.28 mm2, and the average ratio of the fracture area to the total articular surface area was 17.84%. Besides, die-punch was seen in 27 cases and not in 21 cases. The average height of fractures was 21.33 ± 5.38 mm in group A1, 14.38 ± 9.01 mm in group B1, 18.30 ± 7.95 mm in group A2, 14.48 ± 5.37 mm in group B2, 26.26 ± 6.73 mm in group A3, and 12.77 ± 3.07 mm in group B3. Conclusion The height (H) of the posterior malleolar fractures is positively correlated with the fracture area (S) and the fracture area ratio (FAR). The posterior malleolar fractures with “die-punch” tend to have a greater average height than that without “die-punch.” In clinical work, orthopedic surgeons should not only pay attention to the size of the posterior malleolus fracture but also value its height, which hopefully could provide insight into the treatment and prognosis of PMF patients.

Value of pelvic CT sagittal reconstruction for percutaneous insertion of iliosacral screws

Objective To investigate the value of pelvic CT sagittal reconstruction for percutaneous insertion of iliosacral screws. Methods Data of 32 patients who had been treated for pelvic posterior ring injury from June 2015 to March 2017 were retrospectively analyzed. There were 21 males and 7 females, aged from 21 to 75 years (average, 43.2 years). According to Tile classification for pelvic fractures, there were 23 cases of type B (type B1 in 4, type B2 in 13 and type B3 in 6), and 9 cases type C (type C1 in 6, type C2 in 2 and type C3 in 1). The pelvic CT three-dimensional reconstruction was performed before operation, and the reconstructed layer of CT sagittal position was overlapped, and preset S1, S2 sacroiliac joint hollow. Insert the screws according to the preset needle point and passage under the perspective of C-arm X-ray machine during the operation. In 32 cases of patients, 3 cases of type C1, 1 case of type C2 and 1 case of type C3 fractures in sacroiliac joint hollow combined with S1-ilium pedicle screw internal fixation, and the rest of 27 patients were treated by iliosacral screws. The time for each screw placement and the times of X-ray projection were recorded. The position of cannulated screw was observed by CT scan and compared with the preset channel after the operation. Postoperative reduction quality was assessed using Matta radiological criteria and Majeed criteria was used at the final follow-ups to evaluate the pelvic function. Results The operations time was ranged from 40 to 240 min (average, 130 min); and the blood loss was ranged from 20 to 150 ml (average, 80 ml). Altogether 58 iliosacral screws were inserted in 32 patients. The time for each screw placement was ranged from 5 to 15 min (average, 9.5 min); and the number for each screw X-ray projection was ranged from 7 to 15 times (average, 10.2 times). Postoperative CT scan and vascular ultrasound showed that all the iliosacral screws did not penetrate the cortical bone or damaged the vascular nerves, and the error of the preset channel was from 0 to 5 mm (average, 2.2 mm). All fractures healed successfully, and the healing time was 12 to 18 weeks (average, 14.2 weeks). According to Matta radiological criteria, reduction was excellent in 26, good in 3 and fair in 3, with an excellent to good rate of 90.6% (29/32). The follow-up time for the 32 patients was ranged from 6 to 15 months (average, 11.3 months). At the latest follow-ups, X-ray and CT examination showed fine fracture union and no loosening or breakage of screws in all. By the Majeed criteria, the pelvic function was excellent in 21 cases, good in 8 cases, fair in 3 cases, with a good to excellent rate of 90.6% (29/32). Conclusion Preoperative pelvic CT sagittal reconstruction for preset of iliosacral screw insertion point, angle and length can achieve more accurate placement, shorter operative time and less time of X-ray projections. Key words: Tomography, X-ray computed; Pelvis; Sacroiliac joint

A hypothesis for reactivation of pulmonary tuberculosis: How thoracic wall shape affects the epidemiology of tuberculosis.

This study was aimed at determining the cause for the high incidence of tuberculosis (TB) reactivation occurring in males with a low body mass index (BMI). Current thinking about pulmonary TB describes infection in the lung apex resulting in cavitation after reactivation. A different hypothesis is put forward for TB infection, suggesting that this occurs in subclinical apical cavities caused by increased pleural stress due to a low BMI body habitus. A finite element analysis (FEA) model of a lung was constructed including indentations for the first rib guided by paramedian sagittal CT reconstructions, and simulations were conducted with varying antero-posterior (AP) diameters to mimic chests with a different thoracic index (ratio of AP to the transverse chest diameters). A Pubmed search was conducted about gender and thoracic index, and the effects of BMI on TB. FEA modeling revealed a tenfold increase in stress levels at the lung apex in low BMI chests, and a four-fold increase with a low thoracic index, r(2) = 0.9748 P < 0.001. Low thoracic index was related to BMI, P = 0.001. The mean thoracic index was statistically significantly lower in males, P = 0.001, and increased with age in both genders. This article is the first to suggest a possible mechanism linking pulmonary TB reactivation to low BMI due to the flattened thoracic wall shape of young male adults. The low thoracic index in young males may promote TB reactivation due to tissue destruction in the lung apex from high pleural stress levels.

Reliability and accuracy of scout CT in the detection of vertebral fractures

The aim of the present study was to evaluate the reliability of scout CT (sCT) lateral radiograph, in terms of diagnostic accuracy and intra- and interobserver agreement in the detection of vertebral fractures (VFs). 300 CT examinations of the thoracic and/or lumbar spine were collected and independently analysed by 3 musculoskeletal radiologists in 2 different sessions. A semi-quantitative approach was used for VF assessment on sCT, and morphometric analysis was performed when a VF was suspected. Results of multiplanar sagittal CT reconstructions interpreted by the most expert radiologist were considered as gold standard. Arthrosis was also scored. Only vertebral bodies assessable by both sCT and gold standard were considered for the analysis. Area under the receiver operating characteristic curve (AUROC), Cohen's kappa statistic and linear-by-linear association were used for statistical analysis. 1522 vertebrae were considered (130 males and 170 females; ages, 73.0±2.8 years). 73 of 1522 (4.8%) VFs were identified in 34/300 patients (11.3%). In the detection of VFs, the sensitivity and specificity of sCT were 98.7% and 99.7%, respectively. Accuracy (AUROC=0.992±0.008), as well as interobserver agreement (k=0.968±0.008), was excellent. Intra-observer agreement was perfect (k=1.000). Performance of this method was independent of arthrosis, vertebral level and type and grade of VFs. sCT is a simple but very accurate method for the detection of VFs. It should be introduced as a spine evaluation tool for the detection of VFs in examinations that are performed for other diagnostic purposes. sCT lateral radiograph is an accurate tool for the detection of VFs. This technique may be used with several advantages in clinical practice.

Prevalence of Dural Ectasia in Loeys-Dietz Syndrome: Comparison with Marfan Syndrome and Normal Controls

Background and PurposeDural ectasia is well recognized in Marfan syndrome (MFS) as one of the major diagnostic criteria, but the exact prevalence of dural ectasia is still unknown in Loeys−Dietz syndrome (LDS), which is a recently discovered connective tissue disease. In this study, we evaluated the prevalence of dural ectasia in LDS according by using qualitative and quantitative methods and compared our findings with those for with MFS and normal controls.Material and MethodsWe retrospectively studied 10 LDS (6 males, 4 females, mean age 36.3 years) and 20 MFS cases (12 males, 8 females, mean age 37.1 years) and 20 controls (12 males, 8 females, mean age 36.1 years) both qualitatively and quantitatively using axial CT images and sagittal multi-planar reconstruction images of the lumbosacral region. For quantitative examination, we adopted two methods: method-1 (anteroposterior dural diameter of S1> L4) and method-2 (ratio of anteroposterior dural diameter/vertebral body diameter>cutoff values). The prevalence of dural ectasia among groups was compared by using Fisher’s exact test and the Tukey−Kramer test.ResultsIn LDS patients, the qualitative method showed 40% of dural ectasia, the quantitative method-1 50%, and the method-2 70%. In MFS patients, the corresponding prevalences were 50%, 75%, and 85%, and in controls, 0%, 0%, and 5%. Both LDS and MFS had a significantly wider dura than controls.ConclusionsWhile the prevalence of dural ectasia varied depending on differences in qualitative and quantitative methods, LDS as well as MFS, showed, regardless of method, a higher prevalence of dural ectasia than controls. This finding should help the differentiation of LDS from controls.

Surgical Measurement of the Sphenoid Sinus on Sagittal Reformatted CT in the Turkish Population.

The objectives of this study were to determine sinus measurements specific for the Turkish population using CT sagittal thin-slice reconstruction images and to clarify the three-dimensional anatomical features of the sphenoid sinus, along with its surrounding structures, that are relevant to performing an endoscopic sphenoidotomy. Images of 300 patients (165 female, 135 male) were studied. The research was conducted on the axial plane with a 1 mm slice thickness and a 0.6 mm slice interval, and sagittal reconstruction was performed with a 0.4 mm slice interval. Measurements of the sinus were obtained, and the presence of Onodi cells was researched. Line 1 was found to be significantly shorter in the Turkish patients of this study compared to studies of other populations. Lines 4 and 6 were found to be longer on the left side (Line 4 right: 18.8±3.6 mm, left: 19.3±3.4 mm, p=0.027; Line 6 right: 24.1±6.8 mm, left: 24.3±6.8 mm, p=0.008). Lines 2, 3, 4 and 6 were longer in men than in women (p<0.05). In the Turkish population, Line 1 is shorter, so the risk of skull base perforation is greater. Lines 4 and 6 are longer on the left side; thus, choosing the left ostium in sinus dilation is safer. Because of sex differences regarding Lines 2, 3, 4 and 6, sex should be considered in sphenoid sinus procedures.

Usefulness of lateral radiographs for detecting tuberculous lymphadenopathy in children – confirmation using sagittal CT reconstruction with multiplanar cross-referencing

Background. Diagnosis of pulmonary tuberculosis (PTB) in children remains difficult. Lateral chest radiographs are frequently used to facilitate diagnosis, but interpretation is variable. In this study, lateral chest radiographs (CXRs) are evaluated against sagittal CT reconstructions for the detection of mediastinal lymphadenopathy. Aim. To correlate suspected lymphadenopathy on lateral CXR with sagittal CT reconstructions and determine which anatomical group of lymph nodes contributes to each lateral CXR location. Methods and materials. Thirty TB-positive children’s lateral CXRs were retrospectively reviewed for presence of mediastinal lymphadenopathy in 3 pre-determined locations in relation to the carina: retrocarinal, subcarinal and precarinal. Findings of the CT sagittal reconstructions were then correlated with the CXRs for the presence of lymphadenopathy in the same 3 pre-determined areas across the width of the mediastinum. Axial and coronal CT crossreferencing confirmed the position of the lymphadenopathy. Results. The most frequent locations for lymphadenopathy were the subcarinal (28) and right hilar (25). Sensitivity and specificity values of the CXRs were moderate, with the precarinal region having the best sensitivity and specificity for presence of lymphadenopathy. Contribution to each zonal group on lateral CXR were from multiple anatomical lymph node sites. Conclusion. The precarinal zone on CXR had the best specificity and sensitivity, and represented mainly subcarinal and right hilar lymph node groups. Attention should be paid to this area on lateral CXRs for detecting lymphadenopathy in children with suspected PTB.

Usefulness of lateral radiographs for detecting tuberculous lymphadenopathy in children – confirmation using sagittal CT reconstruction with multiplanar cross-referencing

Background. Diagnosis of pulmonary tuberculosis (PTB) in children remains difficult. Lateral chest radiographs are frequently used to facilitate diagnosis, but interpretation is variable. In this study, lateral chest radiographs (CXRs) are evaluated against sagittal CT reconstructions for the detection of mediastinal lymphadenopathy.&#x0D; &#x0D; Aim. To correlate suspected lymphadenopathy on lateral CXR with sagittal CT reconstructions and determine which anatomical group of lymph nodes contributes to each lateral CXR location.&#x0D; &#x0D; Methods and materials. Thirty TB-positive children’s lateral CXRs were retrospectively reviewed for presence of mediastinal lymphadenopathy in 3 pre-determined locations in relation to the carina: retrocarinal, subcarinal and precarinal. Findings of the CT sagittal reconstructions were then correlated with the CXRs for the presence of lymphadenopathy in the same 3 pre-determined areas across the width of the mediastinum. Axial and coronal CT crossreferencing confirmed the position of the lymphadenopathy.&#x0D; &#x0D; Results. The most frequent locations for lymphadenopathy were the subcarinal (28) and right hilar (25). Sensitivity and specificity values of the CXRs were moderate, with the precarinal region having the best sensitivity and specificity for presence of lymphadenopathy. Contribution to each zonal group on lateral CXR were from multiple anatomical lymph node sites.&#x0D; &#x0D; Conclusion. The precarinal zone on CXR had the best specificity and sensitivity, and represented mainly subcarinal and right hilar lymph node groups. Attention should be paid to this area on lateral CXRs for detecting lymphadenopathy in children with suspected PTB.

CT and radiographic analysis of sagittal profile changes following thoracoscopic anterior scoliosis surgery

BackgroundPrevious studies report an increase in thoracic kyphosis after anterior approaches and a flattening of sagittal contours following posterior approaches. Difficulties with measuring sagittal parameters on radiographs are avoided with reformatted sagittal CT reconstructions due to the superior endplate clarity afforded by this imaging modality.MethodsA prospective study of 30 Lenke 1 adolescent idiopathic scoliosis (AIS) patients receiving selective thoracoscopic anterior spinal fusion (TASF) was performed. Participants had ethically approved low dose CT scans at minimum 24 months after surgery in addition to their standard care following surgery. The change in sagittal contours on supine CT was compared to standing radiographic measurements of the same patients and with previous studies. Inter-observer variability was assessed as well as whether hypokyphotic and normokyphotic patient groups responded differently to the thoracoscopic anterior approach.ResultsMean T5-12 kyphosis Cobb angle increased by 11.8 degrees and lumbar lordosis increased by 5.9 degrees on standing radiographs two years after surgery. By comparison, CT measurements of kyphosis and lordosis increased by 12.3 degrees and 7.0 degrees respectively. 95% confidence intervals for inter-observer variability of sagittal contour measurements on supine CT ranged between 5-8 degrees. TASF had a slightly greater corrective effect on patients who were hypokyphotic before surgery compared with those who were normokyphotic.ConclusionsRestoration of sagittal profile is an important goal of scoliosis surgery, but reliable measurement with radiographs suffers from poor endplate clarity. TASF significantly improves thoracic kyphosis and lumbar lordosis while preserving proximal and distal junctional alignment in thoracic AIS patients. Supine CT allows greater endplate clarity for sagittal Cobb measurements and linear relationships were found between supine CT and standing radiographic measurements. In this study, improvements in sagittal kyphosis and lordosis following surgery were in agreement with prior anterior surgery studies, and add to the current evidence suggesting that anterior correction is more capable than posterior approaches of addressing the sagittal component of both the instrumented and adjacent non instrumented segments following surgical correction of progressive Lenke 1 idiopathic scoliosis.

Use sagittal reconstruction CT for making decisions regarding the surgical strategy for cervical ossification of the posterior longitudinal ligament

Use sagittal reconstruction CT to verify the surgical strategy for cervical ossification of the posterior longitudinal ligament (OPLL). A retrospective study of 161 patients (106 males and 55 females) who had undergone surgery for OPLL from July 2007 to November 2010 was performed. The mean age at surgery was 54.5 years (range from 26 to 77 years). The mean follow-up period was 28 months (12 - 54 months). There were 40 patients accept anterior approach surgeries (anterior group) which include 14 cases of anterior cervical corpectomy and fusion and 26 cases of anterior cervical discectomy and fusion. There were 120 patients accept posterior approach surgeries (posterior group) which was spinous process-splitting laminoplasty for cervical myelopathy using coralline hydroxyapatite. One patient accepted combined anterior and posterior approach. According to the sagittal reconstruction CT, the main reason for spinal cord compression was cervical disc herniation in anterior group, and OPLL in posterior group. The level of spinal cord compression was 1 to 2 levels in anterior group, and 1 to 5 levels in posterior group with a major of 2 to 4 levels. As the classification of OPLL, segmental type and circumscribed type were major of segmental type in anterior group and all of the four types were in posterior group, the distribution of each type was average. The patients of posterior group were classified into two groups according to the modified K-line classification, and clinical results were compared between the two groups. The modified K-line was defined as a line that connects the midpoints of the spinal canal at C(2) and C(7) on sagittal CT myelography. Compression to the spinal cord did not exceed the K-line in the modified K-line(+) group and did exceed it in the modified K-line(-) group. Clinical data were compared using t-test or χ(2) test. Correlation analysis was used to determine the relationships of C(2)-C(7) angulation between sagittal reconstruction CT and neutral position X-ray. The patient of anterior group had better recovery rate of the JOA score (72% ± 27%) than the posterior group (59% ± 35%) at the latest follow-up (t = 2.238, P = 0.027). In posterior group, the patients of modified K-line(+) group had better recovery rate of the JOA score (63% ± 37%) than the K-line(-) group (49% ± 30%) at the latest follow up (t = 2.150, P = 0.034). The C(2)-C(7) angulation on sagittal reconstruction CT was 11° ± 9° which has significantly correlated with the C(2)-C(7) angulation on neutral position X-ray which was 10° ± 10° (r = 0.947, P < 0.01). Considering the selection of surgical approach, it should be combined with the main clinical diagnosis for spinal cord compression, the level of compression, the classification of OPLL and the kyphotic alignment of the cervical spine. The modified K-line is a simple and practical tool for making decisions regarding the surgical strategy for cervical OPLL patients.

A careful evaluation of scout CT lateral radiograph may prevent unreported vertebral fractures

ObjectivesOur purpose was to review scout CT lateral radiographs to reveal osteoporotic vertebral fractures unreported by radiologists and to explore scout CT as a potential diagnostic tool in the detection of vertebral fractures. MethodsWe considered 500 patients (303 males, 197 females, age 64.6±13.5 year-old). Our investigation was firstly focused on scout CT lateral images to detect vertebral fractures with a combined semiquantitative and quantitative diagnostic approach. Findings addressed to vertebral fracture were subsequently confirmed by multiplanar sagittal CT reconstructions. Whenever a vertebral fracture was discovered the radiologist report was read and a collection of patient anamnesis followed to understand whether fractures were already known. ResultsIn 44/500 patients (8.8%) the evaluation on scout CT was incomplete or limited for patient/technical-based conditions, and 15 were excluded from the analysis. In 67/485 patients (13.8%) 99 vertebral fractures were detected. Among 67 fractured patients only 18 (26.9%) were previously diagnosed by radiologists. However, in the clinical history of 32 patients vertebral fractures were already known. ConclusionsThe perception and sensibility to vertebral fractures among radiologists are still poor when the assessment of the spine is not the aim of the examination. Short time spent for the evaluation of scout CT lateral radiographs could improve our accuracy.

Pain arising from the atlantooccipital joint

I read with great interest the article entitled “Surgical treatment for atlantooccipital osteoarthritis: a case report of two patients” by Yoshihara et al. [1]. The destruction of O–C1 joints is not rare in rheumatoid arthritis (RA) patients. I sometimes vacillate between performing O–C2 fusion and C1–2 fusion in a patient with mild O–C1 joint destruction in addition to C1–2 joint destruction. O–C2 fusion is a surer method for relieving pain, but extension of the fusion to the occiput reduces the range of motion of the cervical spine and may cause additional complications, such as dysphagia [2]. Although I know that O–C1 destruction causes pain similar to that from the C1–2 joint, C1–2 fusion alone relieves the suboccipital pain markedly in most patients with concomitant mild O–C1 destruction (Fig. 1). In our experience, accidental violation of the O–C1 joint by a slightly too long transarticular screw causes no pain in most patients with C1–2 subluxation. Fig. 1 A 42-year-old woman with RA with atlantoaxial subluxation underwent C1–2 fusion with transarticular screws. Her chief complaint before the operation was neck pain. Sagittal CT reconstruction of the right O–C1–C2 joints 3 days ... When I read the title of the article, I expected that I might learn about how to differentiate the pain from these two joints. However, both cases presented showed destruction of both the C1–2 and O–C1 joints. The authors failed to demonstrate that some of the pain in both patients came from the O–C1 joint. Particularly in case 1, in which the destruction was much milder in the O–C1 joint than in the C1–2 joint, I feel that C1–2 fusion alone may have alleviated the patient’s pain. I thus think that the title of the article is misleading. With this title, the authors should have demonstrated improvement of the pain after only O–C1 fusion, as Grob did [3] or pain relief after O–C2 fusion in the patient with previous C1–2 union and such information would really help us in understanding the pain arising from the upper cervical spine and decide on the fusion range.

Size of noncancerous hilomediastinal lymph nodes measured on coronal and sagittal reconstruction CT images

To determine the sizes of hilomediastinal lymph nodes on coronal and sagittal reconstruction computed tomographic images of subjects without known malignancies. We evaluated 560 lymph nodes of 246 consecutive patients who underwent multidetector-row computed tomography (MDCT) of the chest, then reconstructed coronal and sagittal images on a viewer and measured short-axis diameters of lymph nodes in each station according to the American Thoracic Society (ATS) map for axial, coronal, and sagittal images. On coronal images, short-axis diameters were significantly larger than on axial images in station #4R (P < 0.01). On sagittal images, short-axis diameters were significantly smaller than on axial images in stations #4L (P < 0.01), #10R (P < 0.001), and #10L (P < 0.05). On coronal and sagittal images, short-axis diameters were significantly smaller than on axial images in stations #11R (P < 0.001). In #7, diameters were significantly larger on coronal images than on axial and sagittal images (P < 0.001), and diameters were significantly smaller on sagittal images than on axial images (P < 0.01). In stations #4R, #4L, #7, #10R, #10L, and #11R, measurements of short-axis diameters of hilomediastinal lymph nodes differed on coronal and sagittal images. On coronal and sagittal images, evaluation of hilomediastinal lymph nodes requires unique size criteria for every station.

Anatomical and Radiological Assessment of Trapezial Osteotomy for Trapezial Dysplasia in Early Trapeziometacarpal Joint Arthritis

Opening wedge osteotomy of the trapezial saddle was reported first by Kapandji and Heim (2002) as a possible surgical treatment for early trapeziometacarpal joint arthritis. This study evaluates the feasibility and anatomical risks of the procedure. Ten upper limbs from fresh cadavers were used for this anatomical and radiological study. A dorsolateral opening wedge osteotomy with a 10 degrees correction was performed on each specimen. CT scans and AP radiographs of all the wrists were performed before and after osteotomy to assess the correction of the slope angle, defined as the angle between the longitudinal axis of the second metacarpal and the axis of the trapeziometacarpal articulation. On standard radiographs, mean trapezial slope was 126 degrees preoperatively and 117 degrees postoperatively. On sagittal and coronal CT reconstructions, one case of trapezial translation and two impingements between trapezoid and trapezium bones were identified. Trapezial osteotomy is technically demanding with several possible complications, but merits further study for young patients with Eaton stage 1 or 2 osteoarthritis and an abnormal trapezial slope.

Extraperitoneal bladder rupture with severe lacerations of the urogenital diaphragm: a case report

BackgroundA 65-year woman injured by automobile had an open-book type pelvic fracture and extraperitoneal bladder rupture.Case presentationNon-surgical management was selected because of suspected minor leakage. A follow-up CT cystography on day 21 showed a large urinoma. In the sagittal reconstruction CT images, the bladder was displaced downwards. Surgery was performed. Surgical findings showed that the bladder neck and the urethra were not anchored because of a laceration in the urogenital diaphragm. The bladder base had descended to the inferior margin of the pubic bone and a laceration of about 3 cm was found in the anterior surface of the bladder neck. The laceration was sutured, and the wall of the urinoma was extensively resected. The postoperative course was uneventful.ConclusionAn extraperitoneal bladder rupture associated with a severe laceration in the urogenital diaphragm will be indicated for surgery when the bladder is not anchored and healing is prevented. Sagittal reconstruction CT cystography was effective for this diagnosis.