Preoperative Imaging Data Research Articles

Update of patient-specific maxillofacial implant

Patient-specific implant (PSI) is a personalized approach to reconstructive and esthetic surgery. This is particularly useful in maxillofacial surgery in which restoring the complex three-dimensional (3D) contour can be quite challenging. In certain situations, the best results can only be achieved with implants custom-made to fit a particular need. Significant progress has been made over the past decade in the design and manufacture of maxillofacial PSIs. Computer-aided design (CAD)/computer-aided manufacturing (CAM) technology is rapidly advancing and has provided new options for fabrication of PSIs with better precision. Maxillofacial PSIs can now be designed using preoperative imaging data as input into CAD software. The designed implant is then fabricated using a CAM technique such as 3D printing. This approach increases precision and decreases or completely eliminates the need for intraoperative modification of implants. The use of CAD/CAM-produced PSIs for maxillofacial reconstruction and augmentation can significantly improve contour outcomes and decrease operating time. CAD/CAM technology allows timely and precise fabrication of maxillofacial PSIs. This approach is gaining increasing popularity in maxillofacial reconstructive surgery. Continued advances in CAD technology and 3D printing are bound to improve the cost-effectiveness and decrease the production time of maxillofacial PSIs.

DiscoGel® in patients with discal lumbosciatica. Retrospective results in 25 consecutive patients

IntroductionDiscogenic lumbosciatica is a common disorder in patients between 30 and 40 years old. Because of the frequency and socio-professional impact of this entity, it represents a real public health problem. DiscoGel® is a class III medical device used for nucleolysis to avoid discectomy. The goal of this study was to evaluate the effectiveness of this treatment in patients with discogenic lumbosciatica following unsuccessful conservative medical treatment. Materials and methodsThis is a retrospective, single-center study including 25 patients who were treated with DiscoGel® between 2010 and 2011 at Niort Hospital, France. The severity of lumbar and radicular pain was assessed by a verbal numeric scale (VNS) and patient satisfaction. Patients were classified as successes or failures. ResultsTreatment was found to reduce the severity of lumbar pain in 73% and of radicular pain in 80% of patients in the success group. Treatment was a failure in 64% of patients. A comparison of the two groups showed that a preoperative MODIC 2 MRI signal of the adjacent vertebral end plate was significantly associated with treatment failure (Chi2=8572, P < 0.01). DiscussionThe VNS for lumbar pain and radicular pain decreased in 42% and 50% of patients respectively after the use of DiscoGel®. In our series, DiscoGel® treatment was unsuccessful for discogenic lumbosciatica in 16 patients. These results do not support others in the literature. A lack of statistical power could partly explain these results. The most important result of this study is found in the subgroup analysis which suggests that indications for DiscoGel® treatment could be modified in the future in relation to preoperative imaging data. Level of evidence4.

Augmented reality and cone beam CT guidance for transoral robotic surgery.

In transoral robotic surgery preoperative image data do not reflect large deformations of the operative workspace from perioperative setup. To address this challenge, in this study we explore image guidance with cone beam computed tomographic angiography to guide the dissection of critical vascular landmarks and resection of base-of-tongue neoplasms with adequate margins for transoral robotic surgery. We identify critical vascular landmarks from perioperative c-arm imaging to augment the stereoscopic view of a da Vinci si robot in addition to incorporating visual feedback from relative tool positions. Experiments resecting base-of-tongue mock tumors were conducted on a series of ex vivo and in vivo animal models comparing the proposed workflow for video augmentation to standard non-augmented practice and alternative, fluoroscopy-based image guidance. Accurate identification of registered augmented critical anatomy during controlled arterial dissection and en bloc mock tumor resection was possible with the augmented reality system. The proposed image-guided robotic system also achieved improved resection ratios of mock tumor margins (1.00) when compared to control scenarios (0.0) and alternative methods of image guidance (0.58). The experimental results show the feasibility of the proposed workflow and advantages of cone beam computed tomography image guidance through video augmentation of the primary stereo endoscopy as compared to control and alternative navigation methods.

Does Magnetic Resonance Imaging Improve the Predictive Performance of a Validated Clinical Prediction Rule Developed to Evaluate Surgical Outcome in Patients With Degenerative Cervical Myelopathy?

Ambispective study. To determine whether MRI parameters improve the predictive performance of a validated clinical prediction rule used to assess functional outcomes in surgical patients with DCM. Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in the elderly worldwide. A clinical prediction rule was developed to discriminate between patients with mild myelopathy postoperatively (mJOA ≥ 16) and those with substantial residual neurological impairment (mJOA < 16). Recently, a separate magnetic resonance imaging (MRI)-based prediction model was created. However, a model exploring the combined predictive value of imaging and clinical variables does not exist. One hundred and fourteen patients with MRIs were examined from a cohort of 278 patients enrolled in the AOSpine CSM-North America Study. Ninety-nine patients had complete preoperative imaging and postoperative outcome data. MRIs were evaluated for the presence/absence of signal change on T2- and T1-weighted images. Quantitative analysis of the T2 signal change was conducted and maximum canal compromise and cord compression were calculated. The added predictive performance of each MRI parameter to the clinical model was evaluated using receiver operator characteristic curves. The model developed on our subsample yielded an area under the receiver operator curve (AUC) of 0.811 (95% CI: 0.726-0.896). The addition of imaging variables did not significantly improve the predictive performance. Small improvements in prediction were obtained when sagittal extent of T2 hyperintensity (AUC: 0.826, 95% CI: 0.743-0.908, 1.35% increase) or Wang ratio (AUC: 0.823, 95% CI: 0.739-0.907, 1.21%) was added. Anatomic characteristics, such as maximum canal compromise and maximum cord compression, did not improve the discriminative ability of the clinical prediction model. In our sample of surgical patients, with clinical and image-evidence of DCM, MRI parameters do not significantly add to the predictive performance of a previously published clinical prediction rule. It remains plausible that combinations of the strongest clinical and MRI predictors may yield a similar or a superior prediction model. 3.

Imageologic analysis of thoracolumbar burst fracture of Denis type B

Objective To investigate the roles of pedicle fracture and vertebral compression in thoracolumbar burst fractures of Denis type B. Methods A total of 211 patients with burst fracture of Denis type B were reviewed who had been treated at our department from September 2007 to May 2014. They were analyzed in terms of age, gender, diagnosis, fractured segmental level, ASIA (American Spinal Injury Association) grade of spinal cord injury, and preoperative imaging data (spinal CT and anteroposterior and lateral X-ray films). The associations of pedicle fracture (intact pedicle, unilateral and bilateral pedicle fractures) and vertebral compression (≤1/2 versus>1/2) with age, gender, fractured segmental level and ASIA grade were analyzed statistically. Results Of all the 215 fractured segments of Denis type B, 134 had intact pedicle (62.3% ), 60 unilateral pedicle fracture (27.9% ), and 21 bilateral pedicle fracture (9.8% ). 156 segments (72.6% ) had ≤1/2 vertebral compression and 59>1/2 compression (27.4% ). The incidence of pedicle fracture was 18.9% in cases of ≤1/2 vertebral compression and 36.4% in cases of>1/2 compression. Age, gender, and fractured segmental level had no significant effects on either pedicle fracture or vertebral compression (P>0.05). ASIA grade had a significant effect on pedicle fracture (P=0.020) and there was a linear association between ASIA grade and pedicle fracture (χ2=12.190, P=0.000; Spearman rank correlation coefficient=0.187, P=0.006). ASIA grade had no significant effect on vertebral compression (χ2=3.523, P=0.318). ASIA grade had a significant effect on pedicle fracture combined with vertebral compression (χ2=0.422, P=0.001). Conclusions Gender, age and fractured segmental level may have an insignificant impact on pedicle fracture or vertebral compression. The greater a vertebral compression, the more serious a pedicle fracture. The more serious a pedicle fracture, the more severe a spinal cord injury. Key words: Thoracic vertebrae; Lumber vertebrae; Fractures, bone

Bricker Conduit for Pediatric Urinary Diversion—Should we Still Offer It?

We sought to evaluate long-term outcomes of the Bricker conduit urinary diversion in children. We retrospectively reviewed the database of a single tertiary center for children who had undergone ileal conduit between 1981 and 2011. Patients followed for less than 1 year were excluded. Patient files were reviewed for demographics, diversion indication, preoperative imaging, surgical details, hospital readmissions and followup data. Renal function at baseline and last followup was assessed by estimated glomerular filtration rate, calculated using the modified Schwartz or MDRD (Modified Diet in Renal Disease) formula. Growth charts elucidated patient growth patterns, while an internally designed quality of life questionnaire demonstrated patient and family satisfaction with the procedure. We evaluated 29 children who underwent Bricker conduit at a median age of 10 years (range 2 to 18) and were followed for a median of 91 months (16 to 389). Neuropathic bladder was the underlying diagnosis in 72.4% of cases. Hydronephrosis improved or remained stable in 39 of 55 studied renal units (70.9%). Although no statistically significant difference was observed between mean ± SD baseline (64.5 ± 46 ml/minute/1.73 m(2)) and last followup estimated glomerular filtration rate (54.1 ± 44.9 ml/minute/1.73 m(2)), chronic kidney disease stage had worsened in 13 patients (44.8%), end-stage kidney disease had developed in 11 patients and 9 patients had died. Six patients underwent undiversion after stabilization of renal function. Linear growth was negatively affected in 12 patients (41.4%), and 85% reported poor quality of life. A total of 19hospital readmissions were required in 14 patients to treat diversion related complications. The Bricker conduit does not seem to halt renal deterioration in children. Negative impact on growth and quality of life, and the anticipated rate of complications are significant limitations of the procedure in the pediatric population.

Toward a generic real-time compression correction framework for tracked ultrasound.

Tissue compression during ultrasound imaging leads to error in the location and geometry of subsurface targets during soft tissue interventions. We present a novel compression correction method, which models a generic block of tissue and its subsurface tissue displacements resulting from application of a probe to the tissue surface. The advantages of the new method are that it can be realized independent of preoperative imaging data and is capable of near-video framerate compression compensation for real-time guidance. The block model is calibrated to the tip of any tracked ultrasound probe. Intraoperative digitization of the tissue surface is used to measure the depth of compression and provide boundary conditions to the biomechanical model of the tissue. The tissue displacement field solution of the model is inverted to nonrigidly transform the ultrasound images to an estimation of the tissue geometry prior to compression. This method was compared to a previously developed method using a patient-specific model and within the context of simulation, phantom, and clinical data. Experimental results with gel phantoms demonstrated that the proposed generic method reduced the mock tumor margin modified Hausdorff distance (MHD) from 5.0 ± 1.6 to 2.1 ± 0.7 mm and reduced mock tumor centroid alignment error from 7.6 ± 2.6 to 2.6 ± 1.1mm. The method was applied to a clinical case and reduced the in vivo tumor margin MHD error from 5.4 ± 0.1 to 2.9 ± 0.1mm, and the centroid alignment error from 7.2 ± 0.2 to 3.8 ± 0.4 mm. The correction method was found to effectively improve alignment of ultrasound and tomographic images and was more efficient compared to a previously proposed correction.

Clinical analysis of bone flap craniotomy for 17 patients with chronic subdural hematomas

To deepen the understanding of chronic subdural hematoma and to seek the effective treatment for chronic subdural hematoma (CSDH). We retrospectively reviewed a series of 17 consecutive patients with CSDH, who received the treatment of bone flap craniotomy. To explore the surgical indications for CSDH, the data of imaging appearance, intraoperative findings and postoperative complications were analyzed. Among the patients, 13 were septated CSDH, with the characteristic imaging features such as anti-"3" impression in the inner edge of the hematoma and fibrous strap structure in the hematoma. Four patients were organized CSDH, with strong signals of T1 and T2 as well as hypointense netlike structure within the hematoma cavity while low signal on MRI in the thickened inner membrane. Burr hole trepanation was performed, but no improvement were achieved, whereas the bone flap craniotomy removed the hematoma completely without serious surgical complication except 1 case. Based on the preoperative imaging data, flap bone craniotomy seems to be the first choice for treatment of CSDH.

Severe tricuspid regurgitation is predictive for adverse events in tetralogy of Fallot

ObjectivePatients with surgically repaired tetralogy of Fallot (rTOF) may develop functional tricuspid regurgitation (TR) due to annulus dilation. Guidelines suggest pulmonary valve replacement (PVR) in patients with rTOF with progressive...

Prognostic importance of ultrasound BI-RADS classification in breast cancer patients.

We investigated the prognostic importance of pre-operative Breast Imaging Reporting and Data System classification in ultrasound imaging. Histopathological differences and disease-free survival were analyzed in Breast Imaging Reporting and Data System classification subgroups. Univariate and multivariate analyses were used to identify the prognostic factors. We identified 531 invasive breast cancer patients eligible for this study. Most patients classified as Breast Imaging Reporting and Data System 5 had large tumors and a higher rate of lymph node metastasis. However, hormonal receptor or HER-2 status did not differ according to Breast Imaging Reporting and Data System classification. During a median post-operative follow-up of 42.0 months, 43 patients were diagnosed with a disease-specific event. Disease-free survival was significantly lower in patients with Breast Imaging Reporting and Data System 5 than in patients with Breast Imaging Reporting and Data System 3-4. Subgroup analysis of patients with invasive breast cancer of Stage I showed that Breast Imaging Reporting and Data System 5 was an independent negative prognostic indicator of disease-free survival (hazard ratio 9.195; 95% confidence interval, 1.175-71.955; P = 0.035). Breast Imaging Reporting and Data System classification might be considered as prognostic factors especially in Stage I breast cancer. Further confirmatory studies are needed.

Pulmonary Hemodynamics Simulations Before Stage 2 Single Ventricle Surgery: Patient-Specific Parameter Identification and Clinical Data Assessment.

Single ventricle heart defects involve pathologies in which the heart has only one functional pumping chamber. In these conditions, treatment consists of three staged procedures. At stage 1 pulmonary flow is provided through an artificial shunt from the systemic circulation. Representative hemodynamics models able to explore different virtual surgical options can be built based on pre-operative imaging and patient data. In this context, the specification of boundary conditions is necessary to compute pressure and flow in the entire domain. However, these boundary conditions are rarely the measured variables. Moreover, to take into account the rest of the circulation outside of the three-dimensional modeled domain, a number of reduced order models exist. A simplified method is presented to iteratively, but automatically, tune reduced model parameters from hemodynamic data clinically measured before stage 2 surgery. Patient-specific local hemodynamics around the distal systemic-to-pulmonary shunt anastomosis and the connected pulmonary arteries are also analyzed. Multi-scale models of pre-stage 2 single ventricle patients are developed, including a 3D model of shunt-pulmonary connection and a number of pulmonary arteries. For each pulmonary outlet a total downstream resistance is identified, consistent with measured flow split and pressures. Target pressures such as minimum, maximum or average over one or both lungs are considered, depending on the clinical measurement. When possible, both steady and pulsatile identifications are performed. The methodology is demonstrated with six patient-specific models: the clinical target data are well-matched, except for one case where clinical data were subsequently found inconsistent. Inhomogeneous pressure, swirling blood flow patterns and very high wall shear stress 3D maps highlight similarities and differences among patients. Steady and pulsatile tuning results are similar. This work demonstrates (1) how to use routine clinical data to define boundary conditions for patient-specific 3D models in pre-stage 2 single ventricle circulations and (2) how simulations can help to check the coherence of clinical data, or provide insights to clinicians that are otherwise difficult to measure, such as in the presence of kinks. Finally, the choice of steady vs. pulsatile tuning, limitations and possible extensions of this work are discussed.

Prevalence and distribution of thoracic and lumbar compressive lesions in cervical spondylotic myelopathy.

Study DesignRetrospective cross-sectional study.PurposeThis study analyzed the prevalence and distribution of horacic and lumbar compressive lesions in cervical spondylotic myelopathy as well as their relationships with cervical developmental spinal canal stenosis (DCS) by using whole-spine postmyelographic computed tomography.Overview of LiteratureThere are few studies on missed compressive lesions of the spinal cord or cauda equina at the thoracolumbar level in cervical spondylotic myelopathy. Furthermore, the relationships between DCS, and the prevalence and distribution of thoracic and lumbar compressive lesions are unknown.MethodsEighty patients with symptomatic cervical spondylotic myelopathy were evaluated. Preoperative image data were obtained. Patients were classified as DCS or non-DCS (n=40 each) if their spinal canal longitudinal diameter was <12 mm at any level or ≥12 mm at all levels, respectively. Compressive lesions in the anterior and anteroposterior parts, ligamentum flavum ossification, posterior longitudinal ligament ossification, and spinal cord tumors at the thoracolumbar levels were analyzed.ResultsCompressive lesions in the anterior and anteroposterior parts were observed in 13 (16.3%) and 45 (56.3%) patients, respectively. Ligamentum flavum and posterior longitudinal ligament ossification were observed in 19 (23.8%) and 3 (3.8%) patients, respectively. No spinal cord tumors were observed. Thoracic and lumbar compressive lesions of various causes tended to be more common in DCS patients than non-DCS patients, although the difference was statistically insignificant.ConclusionsSurveying compressive lesions and considering the thoracic and lumbar level in cervical spondylotic myelopathy in DCS patients are important for preventing unexpected neurological deterioration and predicting accurate neurological condition after cervical surgery.

Clinical significance of a false lumen pathway through the arch in acute type A aortic dissection and its influence on cervical branch compromise.

Upon onset of acute type A aortic dissection, the aortic true lumen generally becomes fixed around the supra-aortic branches in the greater curvature and Botallo's ligament in the lesser curvature of the aortic arch. Therefore, the pathways of the false lumen through the arch can be categorized as anterior, bilateral and posterior. We investigated the relationship between a false lumen pathway through the arch and cervical branch compromise, stratified by primary tear location. Sixty-four consecutive patients with acute type A aortic dissection underwent emergency surgery at our institution between March 2005 and October 2013. Of these, 40 cases (63%) were DeBakey type I, 15 cases (23%) were type II and 9 cases (14%) were type III-D (retrograde type A). We conducted a retrospective review of preoperative computed tomographic angiography using three-dimensional image post-processing tools for 43 cases, excluding 15 cases with type II and 6 cases with type I for which preoperative digital image data were not available. Of the 43 cases, 14, 18 and 11 revealed anterior, bilateral and posterior pathways, respectively. Twenty-one cases (49%) showed a primary intimal tear in the ascending aorta (8 anterior, 12 bilateral and 1 posterior), 12 cases (28%) showed a primary intimal tear in the aortic arch (5 anterior, 3 bilateral and 4 posterior) and 10 cases (23%) showed a primary intimal tear in the descending aorta (1 anterior, 3 bilateral and 6 posterior). Twelve of the 14 anterior pathway cases (86%) had a total of 26 supra-aortic branch compromises, 13 of the 18 bilateral pathway cases (72%) had a total of 20 supra-aortic branch compromises, while only 4 of the 11 posterior pathway cases (36%) had a total of four supra-aortic branch compromises. None of the 11 posterior pathway cases had a dissection extending into all 3 supra-aortic branches. Posterior pathway cases generally showed primary tear locations in the arch or descending aorta, and cervical branch compromise was rare. Aortic dissections tended to extend into the cervical branches through the anterior side of the aortic arch. A false lumen pathway through the arch was strongly associated with cervical branch compromise in acute type A aortic dissections.

Clinical outcomes after decompression of the nerve to the teres minor in patients with idiopathic isolated teres minor fatty atrophy

The purpose of this manuscript is to describe what we believe to be the first series of patients surgically treated for idiopathic isolated teres minor atrophy and to present the results of surgical decompression of the nerve to the teres minor. This is a retrospective cohort of 22 patients who underwent decompression of the nerve to the teres minor for isolated teres minor atrophy. Clinical data including duration of symptoms, additional diagnoses, concurrent procedures, preoperative physical examination findings, imaging data, and preoperative visual analog scale (VAS), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores were collected from the medical record. Postoperative patient-based clinical outcome measures including VAS, SST, and ASES scores were obtained during clinical examination or by telephone interview. Average length of follow-up was 26 months. Nine patients had concurrent procedures performed. Preoperatively, 12 of 14 (86%) had external rotation weakness in Hornblower's position. Postoperatively, pain scores decreased an average of 4 points; ASES scores increased 31.7 ± 20.2 points; SST scores increased 3.1 ± 2.3 points. No external rotation weakness was noted postoperatively in any tested patient. Two patients developed adhesive capsulitis. No other complications occurred. Isolated compression of the nerve to the teres minor is a rare and novel clinical entity. In properly selected cases, open release of the fascial sling enveloping the nerve branches to the teres minor can provide relief of symptoms and clinical improvement.

Inter- and intra-observer agreement of femoroacetabular impingement (FAI) parameters comparing plain radiographs and advanced, 3D computed tomographic (CT)-generated hip models in a surgical patient cohort.

The purpose of our study was to investigate whether advanced, 3D computed tomographic (CT)-generated hip models improves inter-and intra-observer agreement when compared to plain radiographs in identifying femoroacetabular impingement (FAI) morphology. Eight consecutive patients who underwent surgery for FAI pathology were selected for this study. Preoperative CT scan image data were used to create high resolution, 3D hip reconstruction models. Four observers (two attending hip surgeons and radiologists) performed a blinded review of preselected radiographs and 3D CT hip models. Alpha and lateral center-edge angle measurements, location of cam lesion and the presence of a "crossover sign" were assessed. Inter- and intra-observer agreement was determined by calculating the intra-class correlation coefficients (ICC) or kappa coefficients to evaluate agreement for categorical variables. The parameter that demonstrated the highest and poorest inter-observer agreement was the presence of a "crossover sign" using 3D CT-generated high resolution hip models (ICC=0.76, p=0.00) and anteroposterior pelvis radiography, respectively (ICC=0.20, p=0.02). Alpha angle values were significantly higher using plain radiographs when compared to 3D hip reconstruction models (61.1°±10.4° versus 55.4°±14.4°, p=0.003). Furthermore, when compared to radiographs, 3D hip reconstruction models demonstrated significantly higher intra-observer agreement (ICC=0.856 versus 0.405, p=0.005) when determining the presence of a "crossover sign". Our findings were suggestive that for most commonly used FAI morphology parameters, CT-generated hip models demonstrated little benefit over plain radiographs in improving inter-observer agreement among providers. III.

A patient-specific surgical simulator using preoperative imaging data: an interactive simulator using a three-dimensional tactile mouse

Preoperative simulation can greatly facilitate the safe and effective conduct of surgical procedures, especially for difficult and complex operations such as hepatectomy and pancreatectomy. A computer simulation system may greatly assist surgeons to preoperatively evaluate an operation and facilitate sharing of information among the operative staff. However, there are several problems with existing simulation systems. We have developed a new surgical simulation system using a patient’s own imaging data, which has some advantages over existing systems. Individual anatomical information obtained through an imaging study is used in this system. In addition it allows interactive control, similar to what a surgeon does in a real operation. Furthermore, a surgeon can control the system intuitively using a three dimensional tactile mouse. Changing the translucency of objects makes it easy to understand complex anatomical relationships. In conclusion, this new system is a patient-specific surgical simulator and can be applied to navigation surgery, medical education and patient communication.

Intraoperative visualization of brain tumors with 5-aminolevulinic acid-induced fluorescence

Precise histopathological diagnosis of brain tumors is essential for the correct patient management. Furthermore, complete resection of brain tumors is associated with an improved patient prognosis. However, histopathological undergrading and incomplete tumor removal are not uncommon, especially due to insufficient intra-operative visualization of brain tumor tissue. The fluorescent dye 5-aminolevulinic acid (5-ALA) is currently applied for fluorescence-guided resections of high-grade gliomas. The value of 5-ALA-induced protoporphyrin (PpIX) fluorescence for intra-operative visualization of other tumors than high-grade gliomas remains unclear. Within the frame of this thesis, we found a significantly higher rate of complete resections of our high-grade gliomas as compared to control cases by using the newly established 5-ALA fluorescence technology at our department. Additionally, we showed that MRI spectroscopy-based chemical shift imaging (CSI) is capable to identify intratumoral high-grade glioma areas (= anaplastic foci) during navigation guided resections to avoid histopathological undergrading. However, the accuracy of navigation systems with integrated pre-operative imaging data such as CSI declines during resections due to intra-operative brainshift. In two further studies, we found that 5-ALA induced PpIX fluorescence is capable as a novel intra-operative marker to detect anaplastic foci within initially suspected low-grade gliomas independent of brainshift. Finally, we showed that the application of 5-ALA is also of relevance in needle biopsies for intra-operative identification of representative brain tumor tissue. These data indicate that 5-ALA is not only of major importance for resection of high-grade gliomas, but also for intra-operative visualization of anaplastic foci as well as representative brain tumor tissue in needle biopsies unaffected by brainshift. Consequently, this new technique might become a novel standard in brain tumor surgery that optimizes the patient management and improves the patient prognosis by maximizing the extent of tumor resection and enabling a precise histopathological tumor diagnosis.

Correlation between pelvic indices, pelvic spatial orientation and lumbar vertebrate instability

To explore the correlation between the stability of lumbar vertebrate and pelvic indices of pelvic incidence (PI), lumber lordosis (LL), pelvic tilt (PT) and sacrum slope (SS). The preoperative imaging data were analyzed retrospectively for 78 patients with lumbar disc protrusion. The values of PI, PT, SS and LL were measured and compared between lumbar vertebrate stability and lumbar vertebrate instability groups. No inter-group statistical difference existed in PI, LL, PT or SS. The average PI of lumbar vertebrate instability group was higher than that of lumbar vertebrate stability group.In patients with L4/5 segmental lesion, SS of lumbar vertebrate instability group was higher than that of lumbar vertebrate stability group (38.7 ± 4.7)° vs (34.0 ± 6.6)°, P = 0.023. And PT in patients with L5/S1 segmental lesion was higher than those with L4/5 segmental lesion (17.5 ± 7.0 vs 14.9 ± 5.3, P = 0.027). No statistical inter-group difference exists in PI. However, higher SS and PT may be risk indicators of instability for L4/5 and L5/S1 segments respectively.

Three‐dimensional interactive model of lumbar spinal structures

The application of three-dimensional software to pre-operative magnetic resonance imaging (MRI) data [1] enables 3D models to be reconstructed and embedded in Portable Document Format (PDF) files [2, 3]. We wish to bring readers' attention to a free resource for 3D MRI images that might be useful for interactive demonstration of lumbosacral structures, specifically relevant to neuraxial blockade: http://diposit.ub.edu/dspace/handle/2445/44844?locale=en (English translation top right of screen)...

Defining Critical White Matter Pathways Mediating Successful Subcallosal Cingulate Deep Brain Stimulation for Treatment-Resistant Depression

Subcallosal cingulate white matter (SCC) deep brain stimulation (DBS) is an evolving investigational treatment for depression. Mechanisms of action are hypothesized to involve modulation of activity within a structurally defined network of brain regions involved in mood regulation. Diffusion tensor imaging was used to model white matter connections within this network to identify those critical for successful antidepressant response. Preoperative high-resolution magnetic resonance imaging data, including diffusion tensor imaging, were acquired in 16 patients with treatment-resistant depression, who then received SCC DBS. Computerized tomography was used postoperatively to locate DBS contacts. The activation volume around the contacts used for chronic stimulation was modeled for each patient retrospectively. Probabilistic tractography was used to delineate the white matter tracts traveling through each activation volume. Patient-specific tract maps were calculated using whole-brain analysis. Clinical evaluations of therapeutic outcome from SCC DBS were defined at 6 months and 2 years. Whole-brain activation volume tractography demonstrated that all DBS responders at 6 months (n = 6) and 2 years (n = 12) shared bilateral pathways from their activation volumes to 1) medial frontal cortex via forceps minor and uncinate fasciculus; 2) rostral and dorsal cingulate cortex via the cingulum bundle; and 3) subcortical nuclei. Nonresponders did not consistently show these connections. Specific anatomical coordinates of the active contacts did not discriminate responders from nonresponders. Patient-specific activation volume tractography modeling may identify critical tracts that mediate SCC DBS antidepressant response. This suggests a novel method for patient-specific target and stimulation parameter selection.