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PubMed2006

[Anatomic evaluation the entry point of C2 pedicle screw].

OBJECTIVE: To study the relevant position of C(2) pedicle to C(2) inferior articular process, set up a technique of C(2) pedicle screw placement with the inferior articular process of axis as an anatomic landmark. METHODS: Fifty C(2) bone specimens were used to measure the distance from the sagittal midline to the medial border, the midpoint and the lateral border of C(2) inferior articular process or C(2) pedicle; the width and the height of the C(2) pedicle were also evaluated. The anatomic relation between the measurements data of C(2) pedicle and that of C(2) inferior articular process were analyzed, and the technique of C(2) pedicle screw fixation was established. RESULTS: The medial border of C(2) inferior articular process was averaged (3.67 +/- 0.41) mm lateral to that of C(2) pedicle, and the midpoint C(2) inferior articular process was averaged (1.15 +/- 0.44) mm lateral to the lateral border of C(2) pedicle, respectively. Using the C(2) inferior articular process as landmark, two techniques was established for C(2) pedicle screw placement. The entry point of method A was located in 2 mm medial and superior to the central point of C(2) inferior articular process; the entry point of method B was at the crossing point of the medial border C(2) inferior articular process with the superior quarter of C(2) inferior articular process. CONCLUSIONS: There is a steady anatomic relation between C(2) pedicle and C(2) inferior articular process, the C(2) inferior articular process could be as a convenient key anatomic landmark to determine the location of C(2) pedicle and the position of C(2) pedicle screw entry point.

Axis, Cervical Vertebra↗
PubMed1994

The influence of body size on linear measurements used to reflect cervical range of motion.

BACKGROUND AND PURPOSE: The purposes of the study were to demonstrate that linear measurements of cervical range of motion are confounded by differences in body size when comparisons are made between groups and to introduce an alternative measure of range of motion that adjusts for variation in body size. SUBJECTS: The sample consisted of 42 subjects (25 female, 17 male) with chronic posttraumatic headaches. METHODS: Using a tape measure, a physical therapist measured the distance between two anatomical landmarks with the subject's neck in the anatomical neutral position and with the subject's neck fully laterally flexed, rotated, and forward flexed. Range of motion was effected with two measurements: the distance between the landmarks at full flexion/rotation and the proportion of distance traversed between the landmarks. RESULTS: The end-of-range values were significantly correlated with body size. No significant correlations emerged between the proportion-of-distance values and body size. CONCLUSION AND DISCUSSION: Linear measurements of cervical motion are potentially confounded by body size when subjects of nonequivalent size are compared. Proportion-of-distance measurement is presented as a more valid alternative to end-of-range measurement.

Adult↗
PubMed2004

Atlas-based recognition of anatomical structures and landmarks and the automatic computation of orthopedic parameters.

OBJECTIVE: This paper describes methods for the automatic atlas-based segmentation of bone structures of the hip, the automatic detection of anatomical point landmarks and the computation of orthopedic parameters to avoid the interactive, time-consuming pre-processing steps for the virtual planning of hip operations. METHODS: Based on the CT data of the Visible Human Data Sets, two three-dimensional atlases of the human pelvis have been built. The atlases consist of labeled CT data sets, 3D surface models of the separated structures and associated anatomical point landmarks. The atlas information is transferred to the patient data by a non-linear gray value-based registration algorithm. A surface-based registration algorithm was developed to detect the anatomical landmarks on the patient's bone structures. Furthermore, a software tool for the automatic computation of orthopedic parameters is presented. Finally, methods for an evaluation of the atlas-based segmentation and the atlas-based landmark detection are explained. RESULTS: A first evaluation of the presented atlas-based segmentation method shows the correct labeling of 98.5% of the bony voxels. The presented landmark detection algorithm enables the precise and reliable localization of orthopedic landmarks. The accuracy of the landmark detection is below 2.5 mm. CONCLUSION: The atlas-based segmentation of bone structures, the atlas-based landmark detection and the automatic computation of orthopedic measures are suitable to essentially reduce the time-consuming user interaction during the pre-processing of the CT data for the virtual three-dimensional planning of hip operations.

Algorithms↗
PubMed2005

Determination of neutral tibial rotational alignment in rotating platform TKA.

UNLABELLED: Use of a fixed anatomic landmark to set rotation of the tibial component may lead to rotational malalignment. Post wear in stabilized components, backside wear in any conforming modular system, and patellar maltracking may result from tibiofemoral rotational incongruence. We aimed to quantify tibial rotational alignment in 109 primary rotating platform TKAs. After trial components were inserted with the knee properly balanced, we recorded the neutral point of the rotating tibial insert, in extension, relative to the most medial aspect of the tibial tubercle. We hypothesized that all neutral points would lie within 10 degrees of the mean. Divergence of the neutral point was recorded as being internal or external to the medial border of the tibial tubercle to the nearest 5 degrees increment. Our results showed a mean divergence of 5 degrees +/- 5 degrees external to the medial border of the tubercle. Five percent of knees, however, had neutral points > or = 10 degrees from the mean. Surgeons who use fixed-bearing modular components with any rotational constraint must be cautious in choosing a fixed anatomic tibial landmark to determine the rotational alignment of the tibial component. Doing so may create tibiofemoral rotational malalignment in full extension that may lead to suboptimal outcomes. LEVEL OF EVIDENCE: Diagnostic study, Level II-3. See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed1997

Scaling of the mandible in squirrels.

We compared the shape of the mandible among New World tree squirrels and selected outgroup taxa using linear measurements and areas defined by the median axis and conventional anatomical landmarks. We modified the median axis technique to define novel measurements, which proved complementary to those obtained from conventional landmarks. Allometric analyses showed that the scaling of the mandible among the New World tree squirrels is generally isometric (as has been observed in other groups of mammals), but diverges from isometry in a tendency in smaller animals for the masseteric ridge to be displaced anteriorly, the condylar process and posterior portion of the ascending ramus to be relatively elongated, and the coronoid process to be shortened. Allometric analyses also revealed the ways and extent that outgrowth taxa deviated from the scaling pattern observed for the New World tree squirrels. A flying squirrel (subfamily Pteromyinae), a moderate-sized callosciurine squirrel, and three species of pygmy tree squirrels from Asia and Africa show mandibular proportions very similar to those predicted for New World tree squirrels of corresponding size. Ground squirrels (tribe Marmotini) and successively more distant relatives such as Aplodontia, two myomorph rodents, and a rabbit show greater differences from the New World tree squirrels in their mandibular proportions. Combining the use of median-axis and conventional measurements makes it possible to examine changing relationships between locations of anatomically homologous landmarks and the geometry of the form.

Animals↗
PubMed1989

[Regional anesthesia in pediatrics].

After having been virtually completely forgotten since the Second World War, paediatric regional anaesthesia has been undergoing a renewal in the last decade. This renewed interest in old techniques is due to several converging factors: a better knowledge of the pharmacology of local anaesthetic agents in the child, the availability of equipment adapted for children, the remarkable haemodynamic stability of the very young child during an epidural block, as well as the need to treat pain not just in the operative period. The child is not, or rather, is not only a small adult. Embryological development is not finished at birth. The incompletely myelinized nervous system as well as the incomplete skeletal ossification will influence local anaesthetic pharmacodynamics and the choice of anaesthetic technique and anatomical landmarks. Aponeurotic sheaths are only poorly attached to anatomical structures, especially nerves. This, together with the fact that epidural fat in the young child is very fluid, explains why some techniques are very efficient, but also why the volumes of required anaesthetic solution are proportionately much more important than in adults. The general pharmacology of local anaesthetic drugs is very close to adults. However, the very important regional blood flow rates, the different body water distribution, the immature neurovegetative system, the weak activity of some enzymes, and the relatively greater importance of the liver and brain by weight explain the differences found in pharmacokinetics, which are differences in degree and not in nature. The choice of the appropriate local anaesthetic agent depends on these factors. In France, the chosen drug will almost exclusively be an amide, mostly lignocaine and bupivacaine. The psychological immaturity of children makes any assessment of pain quite difficult. Moreover, body image has not yet been completely acquired in most cases, so reducing the possibility of conceptualization. The usefulness of techniques requiring an active patient participation, in particular the search for paraesthesia, is therefore rather reduced. Light general anaesthesia and peripheral nerve stimulators (for nerve blocks) are essential, and desirable at least, if not wished by most patients. Caudal anaesthesia is an important technique in the child. It is easy to perform, efficient, with small risk. Its ideal indication is surgery below the umbilicus in the infant and young child. Lumbar epidural anaesthesia requires greater experience as well as proper equipment, especially in the very young child. Peripheral nerve blocks are less used than in adults.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesia, Conduction↗
PubMed1998

Determination of a standard site for the measurement of bone mineral density of the human calcaneus.

Ultrasound of the calcaneus may be used as a cheap, ionising radiation-free and easy to use indicator of skeletal status, and hence of osteoporotic fracture risk. At present ultrasound is not widely used as it suffers from high precision errors. As ultrasound parameters are determined in part by bone mineral density (BMD), an increase in the accuracy and precision of BMD measurements should reduce the precision error associated with ultrasound measurements. The aim of this study was to define an anatomical site on the calcaneus at which accurate and precise measurements of BMD can be made. Ten dry calcanei and 10 cadaveric feet were scanned using a DXA scanner; 9 anatomically defined regions (1 cm2) were selected in the posterior part of the calcaneus for analysis. The centre of region 1 was positioned halfway along the line joining the anterior border of the calcaneal tubercle and the peak of the posterior superior tubercle, and the remaining 8 regions were placed around this central area. The BMD in these 9 regions was compared with the whole bone BMD and the variability of BMD within each of the 9 regions was measured. The reproducibility of the technique was assessed by taking 10 repeated measurements of 2 bone and 2 cadaveric specimens, each specimen being removed and repositioned between measurements. Region 1 was found to be the most representative of total BMD in cadaveric feet. This region also showed the least variability of BMD and consistently gave the lowest coefficients of variation in the reproducibility study both in the bone and the cadaveric specimens. This region is hence the most suitable site on the calcaneus for measuring absolute values of and changes in BMD. The surface position of region 1 was found to be consistently 5/9 along the line at 45 degrees to the vertical, from the lateral malleolus to the heel. The identification of the surface location of region 1 relative to anatomical landmarks of the foot has enabled the same anatomical site to be measured in all subjects. This allows meaningful intersubject comparisons to be made. Preliminary data suggest that precision errors using ultrasound are also reduced when measurements are taken at this region of the calcaneus. The reduction in the precision error of ultrasound assessment of skeletal status may provide a cheap and safe way to identify individuals at risk from osteoporotic fracture.

Aged↗
PubMedDate not supplied

Deep circumflex iliac cutaneous free flap in cats.

OBJECTIVE: To develop and assess the survival of a microvascular cutaneous free flap based on the ventral branch of the deep circumflex iliac (DCI) artery and vein in cats. STUDY DESIGN: Experimental study. ANIMALS: Phase 1: 6 feline cadavers; Phase 2: 2 adult cats; Phase 3: 10 adult cats. METHODS: Phase 1: Selective angiographic study of the deep circumflex iliac artery was completed in 6 feline cadavers. After injection of the DCI artery with barium, high-detail radiographs were made of skin flaps harvested from the lateral flank and thigh region. The extent of the cutaneous angiosome was mapped with regard to the underlying anatomical landmarks. Phase 2: An island flap based on anatomic boundaries of the DCI angiosome derived from phase 1 of the study was elevated in 2 cats. Flaps were observed for 3 weeks for survival. Phase 3: Free skin flaps based on the DCI vessels were harvested in 10 cats and transferred to the dorsal interscapular region. Flaps were evaluated for 2 weeks for survival. Tissue samples were collected for histopathology, and angiograms of the flaps were completed. RESULTS: Phase 1: Angiograms revealed a large primary cutaneous angiosome of the DCI artery located over the lateral femoral region, which extended from the iliac crest to the level of the patella. Phase 2: All island flaps survived for 3 weeks. Phase 3: Six free flaps survived for 2 weeks, and 4 flaps failed completely. Failure of 1 flap occurred because of avulsion of the venous and arterial anastomosis postoperatively. Another cat had intraoperative hemorrhage, which resulted in anemia and hypovolemia and likely caused the flap to fail. The other 2 flaps that failed had poor perfusion intraoperatively and had the longest ischemia times. CONCLUSIONS: The cutaneous DCI free flap in cats may be clinically useful in reconstruction of large cutaneous wounds. The length of ischemia time for successful cutaneous free flap transfer in the cat may be shorter than in other species. CLINICAL RELEVANCE: Large wounds created by trauma or oncologic ablative surgery in cats could be reconstructed with cutaneous microvascular free flap. Additional studies assessing the critical ischemia time of cutaneous flaps in cats and evaluating the use of this flap clinically are needed.

Angiography↗
PubMedDate not supplied

Three-dimensional visualization of the nasal cavity and paranasal sinuses. Clinical results of a standardized approach using multislice helical computed tomography.

OBJECTIVE: The aim of this study was to introduce 3-dimensional (3D) visualization of the nasal cavity and paranasal sinuses as a diagnostic tool and to examination the clinical results of its standardized application. METHODS: One hundred sixty patients with chronic or acute nasal symptoms underwent helical computed tomography scanning and fiberoptic endoscopy of the sinuses, and 120 of them underwent endoscopic sinus surgery. The 3D images were compared with the axial and multiplanar reconstructed images using a checklist comprising important anatomic landmarks. After qualitative assessment of the representation of anatomic structures in healthy subjects, the method was applied to pathologic cases. The 3D images of these patients were correlated with the preoperative and intraoperative findings. RESULTS: Six hundred virtual endoscopies (VEs) were performed. The VE views allowed a realistic illustration of the various pathologic findings, except from cases with highly obstructive sinonasal disease. The correlation between the preoperative fiberoptic endoscopy and the intraoperative findings was significant (r = 0.83, P = 0.001). CONCLUSION: The standardized clinical application of this method serves as an important supplement to 2-dimensional slices and conventional endoscopy.

Adult↗
PubMed1988

Transhiatal blunt esophagectomy.

The operation of transhiatal esophagectomy has been revived in recent years, and several series have reported upon some of the advantages of this procedure over esophagectomy by way of a thoracotomy. Because part of the technique involves a "blind" dissection, it is important that the surgeon is completely familiar with the anatomic relations of the esophagus. A careful anatomic review of these relations was undertaken and important anatomic landmarks have been highlighted with the aid of anatomic dissection. Areas of anatomic fixation are found particularly at the tracheal bifurcation, the dome of the right pleura and the arch of the aorta. The right pleura also crosses the midline between the levels corresponding to the fifth and tenth thoracic vertebrae, and at the eighth thoracic vertebra, there is close proximity of pleurae. A better appreciation of these anatomic features will help the surgeon to decrease the morbidity of the transhiatal esophagectomy.

Esophageal Neoplasms↗
PubMed1989

Alternate approaches to pelvic abscess drainage after cystectomy.

Pelvic abscesses and fluid collections are relatively common complications of major pelvic surgery. When a radical cystectomy has been performed, the ultrasonic acoustic window to normal anatomic landmarks is lost and bowel loops prolapse into the anatomic pelvis. This makes standard suprapubic ultrasonography (US) either difficult or nondiagnostic and often obscures significant pathology. The current use of high-frequency endocavitary US transducers permits an alternate view of the remaining pelvic structures. Coronal transgluteal scans also permit a limited view of the presacral area. These approaches were used in drainage of pelvic abscesses after cystectomy using the transrectal, transurethral, transperineal, and transabdominal routes under US guidance.

Abscess↗
PubMed2003

Motor branch of the rectus femoris: anatomic location for selective motor branch block in stiff-legged gait.

OBJECTIVE: To determine the ideal target point for selective motor branch block of the rectus femoris to treat stiff-legged gait. DESIGN: Descriptive study. SETTING: Anatomic institute of a university school of medicine in Korea. CADAVERS: Twenty-two preserved adult cadavers. INTERVENTION: The anterior thigh of the cadaver was dissected below the inguinal ligament. The motor branches of the 4 heads of the quadriceps were identified and traced from just below the inguinal ligament to the motor points. MAIN OUTCOME MEASURES: The point T, where the motor branch of the rectus femoris is divided into smaller subbranches, was identified. Its location in relation to the surface anatomic landmarks was determined on the basis of the 2 anatomic lines that connect the anterior superior iliac spine to the medial femoral condyle, and the issuing spot of the femoral nerve below the inguinal ligament to the middle of the superior pole of the patellar. RESULTS: The motor branch of the rectus femoris was divided into 2 subbranches at point T just before it reached the muscle. It nearly touched the medial margin of the rectus femoris at a proximal one-fourth to one-fifth point on 2 anatomic lines. The superior subbranch penetrated the muscle fascia at the posterior surface of the proximal one third of the muscle, whereas the inferior subbranch penetrated the muscle fascia at the medial border of the muscle. CONCLUSION: The point T is the most suitable target point to selectively block the motor branch of the rectus femoris without affecting the other 3 motor branches of the femoral nerve in the treatment of stiff-legged gait.

Adult↗
PubMed2003

A comparison of rotational landmarks in the distal femur and the tibial shaft.

The relationship among three anatomic landmarks and the mechanical axis of the tibia was evaluated using magnetic resonance imaging in 30 normal knees in 15 healthy volunteers. These three relationships are calculated for flexion and extension. The angles between the tibial mechanical axis and a line perpendicular to the surgical epicondylar axis, a line perpendicular to the clinical epicondylar axis, and the anteroposterior axis were 3.9 degrees varus, 0.6 degrees varus, and 0.2 degrees valgus, respectively. The mechanical axis of the femur was 3.0 degrees varus relative to the mechanical axis of the tibia. The results of the current study suggest that the surgical epicondylar axis rather than the clinical epicondylar axis or the anteroposterior axis can maintain a more predictable orientation with respect to the mechanical axis of the tibia when moving from flexion into extension.

Adult↗
PubMed2006

Deformable registration of 4D computed tomography data.

Four-dimensional radiotherapy requires deformable registration to track delivered dose across varying anatomical states. Deformable registration based on B-splines was implemented to register 4D computed tomography data to a reference respiratory phase. To assess registration performance, anatomical landmarks were selected across ten respiratory phases in five patients. These point landmarks were transformed according to global registration parameters between different respiratory phases. Registration uncertainties were computed by subtraction of transformed and reference landmark positions. The selection of appropriate registration masks to separate independently moving anatomical subunits is crucial to registration performance. The average registration error for five landmarks for each of five patients was 2.1 mm. This level of accuracy is acceptable for most radiotherapy applications.

Aged↗
PubMed1986

Quantitative assessment of regional left ventricular motion using endocardial landmarks.

In this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the endocardium of eight pigs with a novel retrograde transvascular approach. Marker motion was subsequently recorded with roentgen cinematography and compared with the motion of the landmarks on the endocardial contours detected from the contrast ventriculogram with an automated contour detection system. Linear regression analysis of the directions of the systolic metal marker and endocardial landmark pathways yielded a correlation coefficient of 0.86 and a standard error of the estimate of 10.3 degrees. Landmark pathways were also measured in 23 normal human left ventriculograms. Normal left ventricular endocardial wall motion during systole, as observed in the 30 degrees right anterior oblique view, is characterized by a dominant inward transverse motion of the opposite anterior and inferoposterior walls and a descent of the base toward the apex. The apex itself is almost stationary. On the basis of these observations, a widely applicable model for the assessment of left ventricular wall motion is described in mathematical terms.

Animals↗
PubMed2006

Relationship between the superior attachment type of uncinate process and presence of agger nasi cell: a computer-assisted anatomic study.

OBJECTIVE: The uncinate process (UP) is an important anatomic landmark in frontal recess surgery. Its superior attachment shows great anatomic variability. The agger nasi (AN) cell is another important structure that affects frontal recess anatomy and there is a close neighborhood between them. The aim of this study was to investigate the relationship between superior attachment type of UP and the presence of AN cell. STUDY DESIGN: A retrospective anatomical study. METHOD: Computed tomography scans were evaluated of 486 sides of 243 patients who had had paranasal sinus. In 125 (26%) sides, the superior attachment of the UP could not be identified. In the remaining 361 (74%) sides, the prevalence of superior attachment of UP types and the presence of AN cell in each side were recorded. The results were evaluated with chi2 test. RESULTS: The AN cell was found in 290 (80.3%) of 361 sides. The prevalence of AN cell according to superior attachment of UP types were 79.6% for type 1/2, 90.1% for type 3, 71.4% for type 4, 86.5% for type 5, and 83.3% for type 6. The presence of AN cell according to superior attachment types of UP was not statistically significant (chi2= 3.54, P = 0.315). CONCLUSIONS: The AN cell was found to be present in 80.3% of the cases. However, the relationship between the presence of the AN cell and the superior attachment types of UP was not statistically significant.

Adult↗
PubMed2003

Neuroanatomy of the ureterovesical junction: clinical implications.

PURPOSE: The anatomy of the ureterovesical junction is germane to surgical reconstruction in patients with significant reflux. In this study we refine the description of the neuroanatomy of the distal ureter and ureterovesical junction. MATERIALS AND METHODS: The distal ureter and bladder including the ureterovesical junction from 6 normal human fetuses (3 female and 3 male) at 21 to 40 weeks of gestation were studied using immunohistochemical analysis and 3-dimensional imaging techniques with antibodies against the nonspecific neuronal markers S-100 and nitric oxide synthase (nNOS). RESULTS: Nerves were observed to occupy the medial aspect of the distal ureter. At the ureterovesical junction the nerves encircled the entire ureter. They traveled just outside Waldeyer's sheath, leaving a safe area for surgical dissection under the sheath. As the ureter tunneled into the bladder, the nerves localized to the lateral wall of detrusor muscle. The nerves originating from the ureter and bladder and innervating the trigonal area were immunoreactive to S-100 and nNOS. nNOS positive nerve fibers arising from the bladder and ureteral nerves were found spreading among the detrusor fibers in the trigonal area. CONCLUSIONS: A detailed knowledge of the distal ureteral and ureterovesical junction neuroanatomy and the pathway of these nerves in relation to the anatomical landmarks is critical for preserving bladder function. Based on these anatomical dissections, we would recommend careful dissection within Waldeyer's sheath during ureteral reconstructive surgery.

Female↗