Radiologically anatomic measurement analysis for the third sacral foramen and an efficient implantation protocol for sacral neuromodulation.

AIMS: To define radiologically anatomic measurements for the S3 foramen and develop an efficient and straightforward implantation protocol for sacral neuromodulation (SNM) in a southern Chinese population. METHODS: We retrospectively reviewed 793 adults without sacrococcygeal abnormalities or bony injury. We generated CT-derived three-dimensional volumetric models and collected radiologically anatomic measurements of S3 foramen. A multiple generalized linear regression model was applied to evaluate implantation protocol for SNM. RESULTS: Height, weight, and sacral height were significantly different between enrolled patients based on sex (p < 0.001 for all), while age and sacral width were similar. The measurements L1, L2, A1, and A2 on both sides were similar, while based on sex, those of L1, A1, A2 showed significant differences [7.02 ± 0.90 (M) vs. 6.10 ± 0.99 cm (F) (p < 0.001); 83.05 ± 6.23 (M) vs. 82.08 ± 7.53° (F) (p = 0.005); and 13.31 ± 5.69 (M) vs. 11.97 ± 4.91° (F) (p < 0.001), respectively]. The multiple generalized linear regression model demonstrated that sex was a common independent factor for estimating L1, L2, A1, A2, while the consistency rate between the estimated model and actual measurements was poor. The measurements L1, L2, A1, and A2 were approximately 7.0 cm (M) versus 6.1 cm (F), 1.8 cm (M) versus 1.8 cm (F), 83° (M) versus 82° (F), and 13° (M) versus 12° (F), respectively. CONCLUSIONS: This retrospective study indicates that the radiologically anatomic measurements for the S3 foramen have unique characteristics. Our study provides an efficient and straightforward implantation protocol for SNM, improving its use in China.

Suitability of 3.5-mm screw for the atlas in children: a retrospective computed tomography analysis.

BACKGROUND: The growth and development of the atlas in children has not been studied to date using a large sample size. OBJECTIVE: To study whether a 3.5-mm screw is suitable for the atlas in children, to explore the anatomical size and development of the atlas in 0-14-year-old children, and to provide morphological basis for lateral mass screw internal fixation. METHODS: A Computed Tomography (CT) morphometric analysis was performed on 420 pediatric atlases. In the atlas, D1, D2, D3, D4, and α of the atlas lateral mass were measured. Statistical analysis was performed using one-way ANOVA and Students' t test. The least square method was used for the regression analysis of the change trend in anatomical structure. The curve with the greatest goodness of fit was used as the anatomic trend regression curve. RESULTS: D1, D2, D3, and D4 generally showed an increasing trend with age. The ranges of averages of D1, D2, D3, D4, and α in 0-14 year-old children were as follows: 4.576-9.202 mm, 9.560-25.100 mm, 3.414-10.554 mm, 11.150-27.895, and 12.41°-20.97°, respectively. The trends of the fitting curves of L1 and L3 were power functions, and those of L2 and L4 were logarithmic curves. CONCLUSIONS: CT examination could help in preoperative decision-making, and 3.5-mm screw was found to be suitable for lateral mass screw internal fixation in children aging 2 years and older. D1-D4 increased with age. This provided a certain reference to perform posterior atlantoaxial fusion in children and is of great significance to design posterior atlantoaxial screw in children.

Digital analysis of external fixation area of proximal humerus fractures in elderly patients.

INTRODUCTION: The purpose is based on anatomical basis, combined with three-dimensional measurement, to guide the clinical repositioning of proximal humeral fractures, select the appropriate pin entry point and angle, and simulate surgery. METHODS: 11 fresh cadaveric specimens were collected, the distance of the marked points around the shoulder joint was measured anatomically, and the vertical distance between the inferior border of the acromion and the superior border of the axillary nerve, the vertical distance between the apex of the humeral head and the superior border of the axillary nerve, the vertical distance between the inferior border of the acromion and the superior border of the anterior rotator humeral artery, and the vertical distance between the apex of the humeral head and the superior border of the anterior rotator humeral artery were marked on the 3D model based on the anatomical data to find the relative safety zone for pin placement. RESULTS: Contralateral data can be used to guide the repositioning and fixation of that side of the proximal humerus fracture, and uniform data cannot be used between male and female patients. For lateral pining, the distance of the inferior border of the acromion from the axillary nerve (5.90 ± 0.43) cm, range (5.3-6.9) cm, was selected for pining along the medial axis of the humeral head, close to the medial cervical cortex, and the pining angle was measured in the coronal plane (42.84 ± 2.45)°, range (37.02° ~ 46.31°), and in the sagittal plane (28.24 ± 2.25)°, range (19.22° ~ 28.51°). The pin was advanced laterally in front of the same level of the lateral approach point to form a cross-fixed support with the lateral pin, and the pin angle was measured in the coronal plane (36.14 ± 1.75)°, range (30.32° ~ 39.61°), and in the sagittal plane (28.64 ± 1.37)°, range (22.82° ~ 32.11°). Two pins were taken at the greater humeral tuberosity for fixation, with the proximal pin at an angle (159.26 ± 1.98) to the coronal surface of the humeral stem, range (155.79° ~ 165.08°), and the sagittal angle (161.76 ± 2.15)°, with the pin end between the superior surface of the humeral talus and the inferior surface of the humeral talus. The distal needle of the greater humeral tuberosity was parallel to the proximal approach trajectory, and the needle end was on the inferior surface of the humeral talus. CONCLUSION: Based on the anatomical data, we can accurately identify the corresponding bony structures of the proximal humerus and mark the location of the pin on the 3D model for pin placement, which is simple and practical to meet the relevant individual parameters.

Triangular Mechanical Structure of the Proximal Femur.

OBJECTIVE: The mechanical high modulus structure of the proximal femur could guide clinical surgical treatment and instrument design of proximal femoral fractures. The purpose of this study is to analyze and verify the mechanical structure of the proximal femur. METHODS: A total of 375 patients with intertrochanteric fractures were imaged using computed tomography (CT) scans. Patients were grouped according to age and sex. Cortical and medullary cavity parameters (cortical thickness [CTh], cortical mean density [CM], upper-lower diameter length [ULL], and medial-lateral diameter length [MLL]) were measured at eight planes. Six proximal femoral finite element models of different sexes and ages were constructed. To verify the measurement results, Abaqus was used to implement the force load to describe the von Mises stress distribution, and the maximum von Mises stress values of each wall of the proximal femur were compared. RESULTS: The CTh values of the lower and upper walls were higher than those of the anterior and posterior walls of the femoral neck (p < 0.05). The CM values of the lower and upper walls were higher than those of the anterior and posterior walls of the subcephalic and middle femoral neck (p < 0.05). The ULL value gradually increased from the subcephalic region to the bottom (p < 0.05). The CTh and CM values of the medial and lateral walls were higher than those of the anterior and posterior walls in the femoral trochanteric region (p < 0.05). The MLL value decreased gradually from the plane 20 mm above the upper edge to that 20 mm below the vertex of the femoral lesser trochanter (p < 0.05). The von Mises stress was concentrated on the upper and lower walls of the femoral neck and on the medial and lateral walls of the femoral trochanteric region. The maximum von Mises stress values of the upper and lower walls were higher than those of the anterior and posterior walls of the femoral neck. The maximum von Mises stress values of the medial and lateral walls were higher than those of the anterior and posterior walls in the femoral trochanteric region, except for the plane 20 mm above the upper edge of the femoral lesser trochanter. CONCLUSION: The bone mass of the proximal femur presented a triangular high-modulus distribution, which bore the main stress of the proximal femur. The triangular mechanical structure provides a guideline for the surgical strategy and instrument design of the proximal femur.

Anatomic measures of upper airway structures in obstructive sleep apnea.

OBJECTIVE: Determine if anatomic dimensions of airway structures are associated with airway obstruction in obstructive sleep apnea (OSA) patients. METHODS: Twenty-eight subjects with (n = 14) and without (n = 14) OSA as determined by clinical symptoms and sleep studies; volunteer sample. Skeletal and soft tissue dimensions were measured from radiocephalometry and magnetic resonance imaging. The soft palate thickness, mandibular plane-hyoid (MP-H) distance, posterior airway space (PAS) diameters and area, and tongue volume were calculated. RESULTS: Compared to controls, the OSA group demonstrated a significantly longer MP-H distance (P = 0.009) and shorter nasal PAS diameter (P = 0.02). The PAS area was smaller (P = 0.002) and tongue volume larger in the OSA group (P = 0.004). The MP-H distance, PAS measurements, and tongue volume are of clinical relevance in OSA patients. CONCLUSIONS: A long MP-H distance, and small PAS diameters and area are significant anatomic measures in OSA; however the most substantial parameter found was a large tongue volume.

Anatomic measurement and clinical significance of the middle and lower thoracic segments in normal adults / Medición anatómica e importancia clínica de los segmentos torácico medio e inferior en adultos normales

Thoracic disc herniation (TDH) has high technical difficulty and serious complications, and the clinical anatomy of thoracic intervertebral foramen is less. Collecting 10 adult male cadavers, measuring the longitudinal diameter of the dorsal root ganglion (D1), the transverse diameter of the dorsal root ganglion (D2), horizontal sagittal diameter of the upper edge of the intervertebral disc (S1), the high of intervertebral foramen (H1), the height of articulationes costovertebrales (H2), the height of intervertebral disk (H3), the angel of the dorsal root ganglion (a). The aim of this study is to explore the safe area of middle and lower thoracic section and provide anatomical basis for the selection of operative cannula. Mastering the certain rules of the anatomical structure of the middle and lower thoracic segments, and referring to the above parameters in clinical, is conducive to the selection of the working casing during surgery.

La hernia de disco torácico (TDH) tiene una alta dificultad técnica y complicaciones graves, y la anatomía clínica del agujero intervertebral torácico es menor. Recolectando 10 cadáveres machos adultos, midiendo el diámetro longitudinal del ganglio de la raíz dorsal (D1), el diámetro transversal del ganglio de la raíz dorsal (D2), el diámetro sagital horizontal del borde superior del disco intervertebral (S1), el colmo del intervertebral agujero (H1), la altura de las articulaciones costovertebrales (H2), la altura del disco intervertebral (H3), el ángel del ganglio de la raíz dorsal (α). El objetivo de este estudio es explorar el área segura de la sección torácica media y baja y proporcionar una base anatómica para la selección de la cánula operatoria. Dominar ciertas reglas de la estructura anatómica de los segmentos torácicos medio e inferior, y referirse a los parámetros anteriores en clínica, es propicio para la selección de la carcasa de trabajo durante la cirugía.