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At least 343 records · Page 19Linked to original sources
PubMed1998

Insertion of internal jugular temporary hemodialysis cannulae by direct ultrasound guidance--a prospective comparison of experienced and inexperienced operators.

OBJECTIVE: Previous studies have shown that inexperienced operators have a lower success rate than experienced operators for insertion of internal jugular cannulae using the anatomical landmark technique. The object of this study was to determine the rate of successful insertion, incidence of immediate complications and incidence of infection for temporary hemodialysis cannulae inserted under ultrasound guidance by experienced and inexperienced operators. METHODS: The reason for insertion, patient age, reason for failed insertion, immediate complications, duration of cannula survival and reason for removal were recorded prospectively for 107 attempted cannulations by 7 operators in 72 subjects with renal failure. Operators were defined as "experienced" (more than 3 years postgraduate clinical experience and more than 25 previous central vein cannulae inserted) or "inexperienced" (less than 3 years postgraduate clinical experience and less than 3 previous central vein cannulae inserted). Rates of successful cannulation and incidence of complications were compared for experienced and inexperienced operators. Cannula survival without infection was analysed by Kaplan-Meier survival for experienced and inexperienced operators. RESULTS: The overall success rate of cannula insertion at first site was 103/107 (96.3%) with no difference between experienced and inexperienced operators (56/58 vs. 47/49). 103 internal jugular temporary haemodialysis cannulae were inserted into 72 subjects. The only immediate complication was incorrect positioning of the cannula in 6 cases requiring manipulation. The median survival of hemodialysis cannulae was 14 days (range 1-111). 64.1% cannulae functioned for as long as required. Of the remainder, 33/36 were removed because of presumed cannula related infection. There was no difference in the median duration of cannula survival between experienced and inexperienced operators (15 days versus 12 days; Mann-Whitney point estimate = -1.00; 95% confidence interval -6.00, 3.00). p = 0.66) or in the probability of cannula survival without infection by Kaplan Meier analysis. CONCLUSION: We conclude that ultrasound guided temporary haemodialysis cannulation is a safe procedure with a high rate of success, the success rate for inexperienced operators is much higher than previous studies of cannulation using the anatomical landmark technique and the rate of cannula removal due to infection is not influenced by operator experience.

Catheterization, Central Venous↗
PubMed2000

A method of measuring three-dimensional scapular attitudes using the optotrak probing system.

OBJECTIVE: To develop a method to obtain accurate three-dimensional scapular attitudes and to assess their concurrent validity and reliability. STUDY DESIGN: In this methodological study, the three-dimensional scapular attitudes were calculated in degrees, using a rotation matrix (cyclic Cardanic sequence), from spatial coordinates obtained with the probing of three non colinear landmarks first on an anatomical model and second on a healthy subject. BACKGROUND: Although abnormal movement of the scapula is related to shoulder impingement syndrome, it is not clearly understood whether or not scapular motion impairment is a predisposing factor. Characterization of three-dimensional scapular attitudes in planes and at joint angles for which sub-acromial impingement is more likely to occur is not known. METHODS: The Optotrak probing system was used. An anatomical model of the scapula was built and allowed us to impose scapular attitudes of known direction and magnitude. A local coordinate reference system was defined with three non colinear anatomical landmarks to assess accuracy and concurrent validity of the probing method with fixed markers. Axial rotation angles were calculated from a rotation matrix using a cyclic Cardanic sequence of rotations. The same three non colinear body landmarks were digitized on one healthy subject and the three dimensional scapular attitudes obtained were compared between sessions in order to assess the reliability. RESULTS AND CONCLUSIONS: The measure of three dimensional scapular attitudes calculated from data using the Optotrak probing system was accurate with means of the differences between imposed and calculated rotation angles ranging from 1.5 degrees to 4.2 degrees. Greatest variations were observed around the third axis of the Cardanic sequence associated with posterior-anterior transverse rotations. The mean difference between the Optotrak probing system method and fixed markers was 1.73 degrees showing a good concurrent validity. Differences between the two methods were generally very low for one and two direction displacements and the largest discrepancies were observed for imposed displacements combining movement about the three axes. The between sessions variation of three dimensional scapular attitudes was less than 10% for most of the arm positions adopted by a healthy subject suggesting a good reliability. The Optotrak probing system used with a standardized protocol lead to accurate, valid and reliable measures of scapular attitudes. RELEVANCE: Although abnormal range of motion of the scapula is often related to shoulder pathologies, reliable outcome measures to quantify three-dimensional scapular motion on subjects are not available. It is important to establish a standardized protocol to characterize three-dimensional scapular motion on subjects using a method for which the accuracy and validity are known. The method used in the present study has provided such a protocol and will now allow to verify to what extent, scapular motion impairment is linked to the development of specific shoulder pathologies.

Biomechanical Phenomena↗
PubMed1996

AFNI: software for analysis and visualization of functional magnetic resonance neuroimages.

A package of computer programs for analysis and visualization of three-dimensional human brain functional magnetic resonance imaging (FMRI) results is described. The software can color overlay neural activation maps onto higher resolution anatomical scans. Slices in each cardinal plane can be viewed simultaneously. Manual placement of markers on anatomical landmarks allows transformation of anatomical and functional scans into stereotaxic (Talairach-Tournoux) coordinates. The techniques for automatically generating transformed functional data sets from manually labeled anatomical data sets are described. Facilities are provided for several types of statistical analyses of multiple 3D functional data sets. The programs are written in ANSI C and Motif 1.2 to run on Unix workstations.

Brain↗
PubMed1998

Development and Reliability of a Method for Using Magnetic Resonance Imaging for the Definition of Regions of Interest for Positron Emission Tomography.

Although positron emission tomography (PET) provides important physiological information, a major limitation of this technique is poor anatomical resolution. Combining the superior anatomical resolution of magnetic resonance imaging (MRI) with the physiologic information of PET could be an important advance for clinical and research applications of PET. The purpose of this study was to develop reliable methods for using MRI in the definition of brain regions of interest (ROIs) for application to coregistered PET brain images. First, specific criteria were developed for definition of ROIs on coregistered MRI using anatomical landmarks from a standard anatomical atlas. ROIs were then drawn by three independent raters using the criteria on 11 MRI scans, which had been coregistered to PET [(18)F]2-fluoro-2-deoxyglucose (FDG) brain scans. These MRI-based templates were used to determine activity in various brain regions on the PET scans, which were used in the determination of regional brain metabolic rates. There was a high level of agreement between raters for the measurement of regional metabolic rates, with intra-class correlation coefficients ranging from 0.63-0.98. These findings suggest that specific ROI criteria based on coregistered MRI are a reliable method of measuring activity from PET images. The use of a standard and widely available atlas and readily applicable criteria for ROIs should facilitate a standard method of measurement which can be applied in a similar manner at different PET sites.

Journal Article↗
PubMedDate not supplied

Ultrasound-guided infraclavicular brachial plexus block: an alternative technique to anatomical landmark-guided approaches.

BACKGROUND AND OBJECTIVES: Infraclavicular brachial plexus block has been used less than other approaches because of its less uniform landmarks and the necessity of a longer needle, which increases the patient's discomfort. To overcome these drawbacks, we applied ultrasound guidance to infraclavicular approach and prospectively evaluated its feasibility and usefulness in 60 patients undergoing upper extremity surgery. METHODS: A 7.0-MHz ultrasound probe was placed near the lower edge of the clavicle, and a transverse view of the subclavian artery and vein was visualized. Using a needle guide, a 23-gauge needle was advanced under real-time ultrasound guidance, and 1.5% lidocaine with 1:200,000 epinephrine was injected near the subclavian artery, 15 mm medially and 15 mm laterally to the artery. The extent of sensory and motor block was evaluated at 30 minutes after the injection. RESULTS: An adequate ultrasound image was obtained for all the patients. In 57 patients (95%), surgery was performed without supplementation of any other anesthetics or analgesics. The complete sensory block was obtained in 100% of patients for the musculocutaneous and medial antebrachial cutaneous nerves, 96.7% for the median nerve, and 95% for the ulnar and radial nerves. The complete motor block was achieved in 100% of patients for the musculocutaneous nerve, 96.7% for the median nerve, 90% for the ulnar nerve, and 93.3% for the radial nerve. No evidence of any complications was identified. CONCLUSIONS: Real-time ultrasound guidance facilitates accurate infraclavicular approach to the brachial plexus. It could be used as an alternative to the landmark-guided techniques.

Adolescent↗
PubMed1998

Target localization and treatment verification for intensity modulated conformal radiation therapy of the head and neck region. The AZ-VUB experience. Akademisch Ziekenhuis-Vrije Universiteit Brussel.

PURPOSE: Based on a previous evaluation of a conventional, non-invasive fixation technique in combination with a commercially available system for conformal radiation therapy by means of intensity modulation of the treatment beam some modifications have been proposed with respect to target localization and treatment verification. This paper reports on an on-going study of which some preliminary results are presented and discussed with respect to reproducibility of the treatment set-up and verification of the dose. METHODS AND MATERIALS: A slice-by-slice arc-rotation approach was used to deliver a conformal dose to the target and patient fixation was performed by means of a thermoplastic cast. In a previous study a procedure for target localization and verification of patient positioning suitable for this particular treatment technique had been developed and verified dosimetrically with an anthropomorphic phantom: both absolute dose measurements (alanine and thermoluminescent detectors) and relative dose distribution measurements (film dosimetry) have been applied. Two issues needed special attention, being: a) increased accuracy in patient set-up and b) deviations between measured and predicted dose values to organs at risk (OAR) in extreme situations. In a 2nd phase, fiducial markers fixed to customized ear moulds and a bite block have been introduced for target localization and verification of patient set-up on a day-to-day basis. A dosimetric verification by means of TLD and an anthropomorphic phantom has been performed to investigate the possible influence of leakage dose. RESULTS: The dose verification with the anthropomorphic phantom yielded a ratio between measured and predicted dose values of 1.0 for typical cases. However, large deviations (i.e. measured/calculated = 2.9) have been observed in cases with extreme dose constraints to the OAR due to a leakage dose of approximately 0.5%. Dosimetric verification showed good agreement with the dose calculation once the limitations of the system (10% of the target dose to the OAR) had been taken into consideration. Day-to-day variations in patient set-up of 0.3 cm (translations) and 2.0 degrees (rotations) were considered acceptable for this particular patient population in an initial phase, whereas variations of less than 0.1 cm can be achieved with the introduction of ear moulds and daily monitoring in a second phase. Preliminary results show a reproducibility of 0.08 cm in positioning of the fiducial landmarks with respect to anatomical landmarks. CONCLUSIONS: The non-invasive fixation technique in combination with fiducial markers fixed to individualized ear moulds and a bite block proved to be acceptable for IMRT of the head and neck region and allow for daily monitoring of patient set-up. The latter becomes mandatory if an accuracy of 0.1 cm and 1.0 degree is required. A clinical trial has been initiated recently to generate substantial data on the accuracy of the presented procedure for treatment set-up. Dose measurements confirmed the predicted dose values to the target and OAR, however, a physical limitation is represented by the 0.5% leakage through the leaves in that dose constraints to the OAR should be limited to 10% of the target dose.

Algorithms↗
PubMed1979

Precise identification of radiographic acetabular landmarks.

Accurate radiographic demonstration of pelvic anatomical landmarks is predicated on proper positioning of the patient. Interpretation of acetabular abnormality especially may be difficult when to the artifact created by pelvic asymmetrical positioning there is added true femoral head displacement. A radiograph of hip joint abnormalities in a child with congenital hip dislocation where positional distortion was present served to illustrate the problem. To clarify the direction and magnitude of acetabluar alterations with specific pelvic positions, radiographs and photographs were taken of anatomic models outlined by suitably placed lead markers. Clues to inappropriate pelvic positioning are loss of symmetry in the widths of the iliac alae, sizes of the obturator foramina, and positions of the "tear drop" figures.

Acetabulum↗
PubMed1999

[Simplified approach to ablation in atrial flutter using a single catheter electrode. Based on 70 cases].

The object of this study was to assess the feasibility, efficacy and risks of ablation of common atrial flutter using a single catheter electrode. Recent studies have shown that radiofrequency ablation is effective for interrupting atrial flutter but with a variable rate of recurrence. Therefore, the search for a conduction block in the isthmic region has become the reference method for reducing the incidence of recurrence but this requires the use of costly material. The necessity of single usage has incited research to find a less costly method without compromising efficacy. The authors reviewed the results in 70 consecutive patients with common atrial flutter resistant to anti-arrhythmic medication. The site of ablation was located using anatomical landmarks and electrophysiological criteria. The anatomic site was situated either on a lateral isthmus or, to a variable degree, a septal isthmus; the electrophysiological criterion was an endocavitary auriculogramme, the amplitude of which had to decrease by more than 2/3 after application of the radiofrequency. The technique was interrupted not after the interruption of the flutter but after obtaining a microvoltage atrial activity along the isthmus. Radiofrequency energy of 10 to 50 W was delivered at each site for 90 seconds. Atrial flutter was interrupted in all 70 patients (100%). The average number of applications to interrupt the flutter was 12.67 and to create a microvoltage barrier 14.58. The average duration of the radiofrequency procedure was 50.43 minutes. After an average of six months' follow-up, the recurrence rate was 13%: 9 patients, 5 of whom underwent a second session of radiofrequency ablation. There were no immediate complications after this method of ablation.

Adult↗
PubMed2004

[Clinical analysis of 58 cases intraoperative image-guidance in nasal endoscopic surgery].

OBJECTIVE: To evaluate the availability and our experience of intraoperative image-guidance in endoscopic nasal surgery. METHODS: Fifty-eight cases of endoscopic nasal surgery with intraoperative image-guidance were retrospectively reviewed, including 39 cases of chronic sinusitis with or without nasal polyp; 3 cases of necrotizing maxillary sinusitis; 6 cases of sphenoid sinus cyst; 2 cases of nasopharyngeal angiofibroma; 1 case of cranio-nasal meningioma; 1 case of traumatic cerebrospinal rhinorrhea; 1 case of traumatic optic nerve lesion. All patients were operated on with Brain Lab operation imaging navigation system and nasal endoscope. RESULTS: The preoperative preparatory time would take 10-20 minutes, including coordination, head holder localization, conventional instrument registration. In our cases, the localization accuracy between 3-D image landmarks of navigation system and actual anatomical landmarks was less than 1.5 mm. The optic nerve and other anatomical points could be orientated accurately in intraoperative procedures. No complication occurred. CONCLUSIONS: Nasal endoscope combined with image-guidance systems provides accurate anatomical localization of nasal cavity, sinuses and anterior skull base with enlarged operation field. It is possible for surgeons to observe the surrounding important anatomical structures during endoscopic nasal surgery. It could increase the effectiveness and decrease surgical complications, especially in complicated cases.

Adolescent↗
PubMed1989

Quantification of periodontal attachment at single-rooted teeth.

The measurement process of attachment loss has been criticized in recent years. Problems with clinical interpretation, precision of the measurement, and statistical manipulation of the obtained data, are some of the problems associated with the present methodology. The purpose of the present study was to propose an alternative measurement process which addresses some of the existing problems by estimating the lost attachment surface area (LAS) and the remaining attachment surface area (RAS) from a combination of clinical measurements. The results show that a linear combination of several sources of clinical information can be used to predict RAS and LAS. A diagnostic model for LAS (R2 = 81.5%) predicts the square root of LAS with information obtained from bucco-lingual attachment level measurements, the radiographic lost attachment area, the gingivitis index and the radiographic tooth length. This model increases the precision of the estimate of LAS by a factor of 1.86 when compared to the estimate of LAS using only attachment level measurements. A diagnostic model for RAS (R2 = 75.5%) predicts the square root of RAS with the information obtained from the remaining radiographic attachment area, the gingivitis index and the mobility index. Both linear inference models are constructed with measurements of anatomical landmarks to avoid the discrepancy between anatomical and clinical measurements in the produced estimates. It is concluded that modeling of periodontal data provides a simple, inexpensive, and precise diagnostic tool for predicting the lost and the remaining periodontal attachment of single-rooted teeth. Measurement processes of this type could provide a convincing basis for the evaluation of clinical decisions and research questions.

Cuspid↗
PubMed2004

[Imaging-navigated endoscopic sinus surgery].

OBJECTIVE: To evaluate the advantages and disadvantages of different type of image-guidance system in endoscopic sinus surgery. METHODS: Fifty-three endoscopic sinus surgery were performed under different type of image-guidance system, there were 24 chronic sinusitis with or without nasal polyp, 4 juvenile nasopharyngeal angiofibroma, 8 pituitary adenoma, 9 ethmoid ossifying fibroma, 2 nasopharyngeal mixed tumor, 1 nasal leiomyoma, 3 fungal sinusitis, and 2 inverting papilloma. RESULTS: In all cases, the preoperative time was 15-30 minutes, the registration rate were 1.3-2.0, the localization accuracy was within 1 mm. Compared with the traditional endoscopic sinus surgery, the operating time was similar, without obvious difference. No complication occurred. CONCLUSION: All types of image-guidance system could work well with endoscopic system, each of them had its own shortages. Every type of image-guidance system could identify the borders and critical anatomical structures in the corresponding CT data, especially in cases in which anatomical landmarks were no longer present, with anatomical variation, intranasal and anterior skull base tumor. Combined with endoscopic surgery, the image-guided endoscopic surgery provided accurate tumor resection while preserving normal tissue, increased surgical effectiveness, decreased overall surgical complications. It is believed that the image-guidance system is a useful tool for endoscopic sinus surgery.

Adolescent↗
PubMed1998

A proposed glossary of terminology related to the surgical treatment of vulvar carcinoma.

BACKGROUND: The authors' objective was to provide a glossary of terminology related to the surgical treatment of invasive vulvar carcinoma. There is currently no consensus in the literature regarding the names of the surgical procedures used to treat this disease. METHODS: A surgical glossary should be supported by clear definitions and acceptance of notions related to topographic anatomy that are specific to the surgical practice. A critical review of the classic, chiefly used Italian, French, German, and English textbooks of anatomy revealed some discrepancies and lack of uniformity in descriptions of vulvar and inguinal fascial structures and lymph nodes, which represent the principal landmarks of surgical treatment. In the proposed glossary, the descriptions of these anatomic landmarks integrate classic anatomic knowledge, data from recent gynecologic studies of inguinal anatomy, and the clinical experiences of the authors. RESULTS: The glossary is composed of 16 surgical definitions, which are divided into 3 main sections of terminology describing the surgical treatment of the: 1) vulva, 2) inguinal lymph nodes, and 3) pelvic lymph nodes. The fundamental objective behind the glossary is to describe the area and the depth of the surgical procedure. Three determinants of the area (local, partial, and total) and three determinants of the depth of surgery (superficial, simple, and deep) were used to arrive at the fully articulated definitions in the glossary. CONCLUSIONS: The authors are aware that the proposed glossary should not be considered a definitive one; however, it could serve as a good basis for further debate. The terms employed in the glossary are accompanied by anatomic and descriptive references to help avoid confusion and promote better understanding among gynecologic oncologists who are involved in the treatment of vulvar carcinoma.

Female↗
PubMed2006

The endoscopic endonasal approach to the lateral recess of the sphenoid sinus via the pterygopalatine fossa: comparison of endoscopic and radiological landmarks.

OBJECTIVE: The endoscopic endonasal approach offers the opportunity to reach the pterygopalatine fossa, the lateral recess of the sphenoid sinus, and other areas of the cranial base through a minimally invasive approach. This study compares the anatomy of these areas when observed through an endoscopic endonasal view with the anatomy of the same regions as they appear in computed tomographic scans. The aim was to identify and correlate the corresponding anatomic structures, providing the surgeons with anatomic landmarks to guide them when operating in these areas through an endoscopic endonasal approach. METHODS: An anatomic dissection of six fixed cadaver heads was performed by an endoscopic endonasal approach. A step-by-step comparison of endoscopic and radiological images was made to identify the landmarks of the surgical field. RESULTS: The step-by-step comparison of endoscopic and radiological images acquired during the endoscopic endonasal approach to the lateral recess of the sphenoid sinus via the pterygopalatine fossa allowed the identification of all the relevant anatomic landmarks of the procedure. CONCLUSION: The endoscopic endonasal approach via the pterygopalatine fossa offers direct, minimally invasive access to the lateral recess of the sphenoid sinus, which can be monitored in each phase through consistent radiological imagery.

Cadaver↗
PubMed2005

Using the frontal branch of the superficial temporal artery as a landmark for locating the course of the temporal branch of the facial nerve during rhytidectomy: an anatomical study.

BACKGROUND: Previous studies have proposed that the frontal branch of the superficial temporal artery could be used to determine the course of the temporal branch of the facial nerve; however, these studies have not documented this relationship. The objective of this study was to thoroughly examine the courses of the frontal branch and temporal branch in the temporal region and to describe their relationship in detail. The operating technique used to avoid damaging the temporal branch in the rhytidectomy also is discussed. METHODS: An anatomical study was performed on 30 temporoparietal regions from 10 fixed adult cadavers and five fresh cadavers. Twenty halves of head-vascular-cast specimens also were observed. RESULTS: Depending on whether the bifurcation point of the superficial temporal artery is superior or inferior to the horizontal line of the superior orbital rim, the frontal branch can be classified as having a high-location or low-location type. The temporal branch and its terminal twigs run deeper into the superficial temporal fascia and are inferior to the frontal branch in the high-location type. In the low-location type, one or more terminal twigs of the temporal branch interweave with the frontal branch above the horizontal plane of the upper orbital rim and terminate below the frontal eminence. The temporal branch locates within a triangular area formed by the lower aspect of the zygomatic arch, the frontal branch, and the vertical line where it crosses the highest point of the frontal eminence CONCLUSION: The frontal branch can be the anatomical landmark used to locate and protect the temporal branch during rhytidectomy.

Dissection↗
PubMed2006

Comparison of cuffed and uncuffed preformed oral pediatric tracheal tubes.

BACKGROUND: In preformed cuffed tracheal tubes the position of the cuff within the airway is given by its distance to the tube bend placed at the lower teeth. The aim of this study was to compare the design of cuffed and uncuffed preformed pediatric oral tracheal tubes with regard to anatomical landmarks. METHODS: Complete series of cuffed and uncuffed preformed oral pediatric tracheal tubes sized from internal diameter 3.0-7.0 mm if available were ordered from five different manufacturers. The distance from the bend to the distal tube tip and to the upper border of the cuff were measured and compared with anatomical airway landmarks in the developing child. RESULTS: Between cuffed and uncuffed tracheal preformed tubes up to 37 mm differences in the bend-to-tracheal tube tip distances were found for given age groups. Thus uncuffed preformed tracheal tubes were more at risk for inadvertent endobronchial intubation than cuffed preformed tracheal tubes. Comparison of bend-to-upper border of the cuff distances with teeth-to-vocal cord distances calculated from anatomical data revealed that several of the tracheal tube cuffs become positioned within the subglottic larynx or even within the vocal cords when inserted according to the bend. CONCLUSIONS: There is a need for improvement in cuffed preformed pediatric tracheal tubes, namely a standard bend-to-tracheal tube tip distance to allow a safe insertion depth, a short cuff placed on the tube shaft as distally as possible and an intubation depth mark to verify a proper position of the cuff in the trachea.

Adolescent↗
PubMed2003

Repeatability of gait data using a functional hip joint centre and a mean helical knee axis.

Repeatability of traditional kinematic and kinetic models is affected by the ability to accurately locate anatomical landmarks (ALs) to define joint centres and anatomical coordinate systems. Numerical methods that define joint centres and axes of rotation independent of ALs may also improve the repeatability of kinematic and kinetic data. The purpose of this paper was to compare the repeatability of gait data obtained from two models, one based on ALs (AL model), and the other incorporating a functional method to define hip joint centres and a mean helical axis to define knee joint flexion/extension axes (FUN model). A foot calibration rig was also developed to define the foot segment independent of ALs. The FUN model produced slightly more repeatable hip and knee joint kinematic and kinetic data than the AL model, with the advantage of not having to accurately locate ALs. Repeatability of the models was similar comparing within-tester sessions to between-tester sessions. The FUN model may also produce more repeatable data than the AL model in subject populations where location of ALs is difficult. The foot calibration rig employed in both the AL and FUN model provided an easy alternative to define the foot segment and obtain repeatable data, without accurately locating ALs on the foot.

Ankle Joint↗
PubMed1998

Left planum temporale surface correlates with functional dominance during story listening.

The relationship between anatomical asymmetry of the planum temporale (PT) and functional lateralization for language comprehension was studied in 14 normal volunteers, including five left-handers (LH). PT surfaces and asymmetry were measured in each subject using structural MRI, while functional lateralization was assessed on individual regional cerebral blood flow (rCBF) difference images of a PET-H2(15)O activation protocol in which a story listening condition was contrasted with a control state. Significant positive correlations were found between the left PT surface and the amount of NrCBF increase during the story listening in the left superior temporal gyrus as well as with the left-right activation index in the superior temporal and the temporal pole. Functional imaging data were correlated neither with the right PT surface nor with the right-left PT surface asymmetry index. However the latter index was correlated with handedness scores. The present results indicate that the size of the left PT is the relevant anatomical landmark for language dominance, and demonstrate that anatomical asymmetries are part of the functional variability for language.

Adult↗
PubMed2000

Modification of C1-C2 transarticular screw fixation by image-guided surgery.

STUDY DESIGN: This is a feasibility study of image-guided surgery for C1-C2 transarticular screw fixation comparing postoperative screw position in a nonrandomized prospective cohort with a historic control group in which fluoroscopic guidance was used alone. OBJECTIVES: To evaluate the potential benefits and disadvantages of image-guided surgery for C1-C2 screw placement. SUMMARY OF BACKGROUND DATA: C1-C2 transarticular screw fixation is biomechanically superior to other current surgical stabilization procedures. The original technique for C1-C2 screw placement relies on anatomic landmarks and intraoperative fluoroscopy. Screw misplacement or anatomic variations can result in vertebral artery injury. Image-guided surgery involves using computed tomography (CT) data to plan the optimal screw trajectory before surgery and then use this data to guide screw placement during the actual surgery. Promising results of this technique are reported in the literature, but no direct comparison between image-guided surgery and conventional surgical techniques has been previously reported. METHODS: The image-guided surgery group consisted of 37 prospective patients. The historic control group included 78 patients who had similar surgeries performed using only fluoroscopic guidance. For the image-guided surgery group, subluxation was reduced by positioning at the time of CT examination. The CT data were transferred to a StealthStation (Sofamor-Danek, Memphis, TN) surgical planning and guidance computer system, and an optimal screw trajectory was determined for the right and left transarticular screws. After matching the surgical field to the virtual computer field, C2 was drilled according to the planned screw trajectory, and screws were placed. Plain radiographs and CT were used for postoperative evaluation of the image-guided surgery group. RESULTS: Image-guided surgery reduced but did not eliminate the risk of screw misplacement. Surgical time was not increased overall. CONCLUSIONS: Image-guided surgery is an effective tool for the achievement of correct screw placement in C1-C2 transarticular screw fixation procedures. The procedure remains technically demanding.

Axis, Cervical Vertebra↗