Optimal Insertion Point Research Articles

Off-Label Use of an External Hand Fixator for Craniomaxillofacial Fractures-An Anatomical Feasibility Study.

The lack of resources limits the treatment of craniomaxillofacial fractures (CMF) in low-income countries (LIC). Therefore, Barton bandages and/or interdental wiring are considered in these regions. Fracture reduction is maintained by permanent occlusion for 6 weeks, which often leads to limited compliance and dissatisfying results. The aim of this cadaver-based study is to evaluate the feasibility of the use of an external face fixator (EFF) for the treatment of CMF, its biomechanical values and to define the optimal pin insertion points and angles. An AO hand fixator was used. CMF of types Le Fort 1-3 with split fractures of the hard palate were treated with EFF on 13 anatomical specimens. Fractures were created using a chisel, and pins were placed in specific anatomical regions. The maximal pull-out force [N] of pins was analysed by a tensile force gauge, and Fmax of the mandibular pins was evaluated. Computer tomography scans were performed on the healthy, fractured and EFF-treated skulls. The pull-out forces for the single pins were mandibular pins (n = 15, median 488.0 N), supraorbital pins (n = 15, median 455.0 N), zygomatic pins (n = 14, median 269.1 N), medial hard palate pins (n = 12, median 208.4 N) and lateral hard palate pins (n = 8, median 49.6 N). The results indicate that the operation technique is feasible, and the stability of the EFF is sufficient for maintaining the reduction. The required pins can safely be inserted into the described areas with good reduction results. Using EFF offers a feasible alternative to the non-surgical treatment of CMF in LIC.

Optimal retractor insertion point for nerve safety during total hip arthroplasty: an anatomical study on the femoral and sciatic nerves in relation to hip motion.

Nerve injury is one of the most serious complications of total hip arthroplasty (THA). It is suspected to be a result from nerve compression or direct injury caused by an acetabular retractor. The anatomical relationship between the acetabular rim and the femoral and sciatic nerves, including hip motion, has not been investigated. This study aimed to identify the optimal position for retractor insertion during THA to prevent nerve damage. A total of 28 hip joints from 14 freshly frozen cadavers were used. Using an anterolateral approach, each cadaver was immobilised in the lateral decubitus position and deployed to measure the distance between the nerves and the acetabular rim, while the hip joint was changed to the extension, neutral, and flexion positions. Three femoral nerves were closest to the anterior margin of the acetabulum at 90° and 120° of extension and farthest away at 30° of flexion. The sciatic nerve was closest to the posterior margin of the acetabulum at 90° and 120° of flexion and farthest away at 30° and 150° of extension compared with the other points. To prevent nerve damage during THA, we suggest that the retractor be inserted at the points where the nerves are the farthest away, such as at 30° and 150°. The femoral and sciatic nerves vary in their movements depending on the hip position. Therefore, the safe insertion of a retractor is recommended for hip flexion of the femoral nerve and extension of the sciatic nerve. Additionally, it is important to carefully insert the retractor along the acetabular margin without penetrating the joint capsule. Overall, this study provides valuable insights into the anatomical location and movement of the femoral and sciatic nerves in relation to hip motion and can help inform surgical techniques for safer THA.

Outcome Following Intramedullary Nailing of Tibial Diaphyseal Fractures: Suprapatellar Nail Insertion Results in Superior Radiographic Parameters But No Difference in Mid-Term Function.

The primary aim of this study was to compare the radiographic parameters (nail insertion-point accuracy [NIPA] and fracture malalignment) of patients who had undergone tibial intramedullary nailing via the suprapatellar (SP) and infrapatellar (IP) approaches. The secondary aims were to compare clinical outcomes and patient-reported outcomes (PROs) between these approaches. All adult patients with an acute tibial diaphyseal fracture who underwent intramedullary nailing at a single level-I trauma center over a 4-year period (2017 to 2020) were retrospectively identified. The nailing approach (SP or IP) was at the treating surgeon's discretion. Intraoperative and immediate postoperative radiographs were reviewed to assess NIPA (mean distance from the optimal insertion point) and malalignment (≥5°). Medical records and radiographs were reviewed to evaluate the rates of malunion, nonunion, and other postoperative complications. The Oxford and Lysholm Knee Scores (OKS and LKS) and patient satisfaction (0 = completely dissatisfied, 100 = completely satisfied) were obtained via a postal survey at a minimum of 1 year postoperatively. The cohort consisted of 219 consecutive patients (mean age, 48 years [range, 16 to 90 years], 51% [112] male). There were 61 patients (27.9%) in the SP group and 158 (72.1%) in the IP group. The groups did not differ in baseline demographic or injury-related variables. SP nailing was associated with superior coronal NIPA (p < 0.001; 95% confidence interval [CI] for IP versus SP, 1.17 to 3.60 mm) and sagittal NIPA (p < 0.001; 95% CI, 0.23 to 0.97 mm) and with a reduced rate of malalignment (3% [2 of 61] versus 11% [18 of 158] for IP; p = 0.030). PROs were available for 118 of 211 patients (56%; 32 of 58 in the SP group and 86 of 153 in the IP group) at a mean of 3 years (range, 1.2 to 6.5 years). There was no difference between the SP and IP groups in mean OKS (36.5 versus 39.6; p = 0.246), LKS (71.2 versus 73.5; p = 0.696), or satisfaction scores (81.4 versus 79.9; p = 0.725). Compared with IP nailing, SP nailing of tibial shaft fractures was associated with superior NIPA and a reduced rate of intraoperative malalignment but not of malunion at healing. However, the superior NIPA may not be clinically important. Furthermore, there were no differences in PROs at mid-term follow-up. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

LARAI portal provides a safe method for lateral meniscus repair: three-dimensional computed tomography and cadaveric assessment

BackgroundLateral, All-Round and All-Inside (LARAI) portal is a viewing or working portal for observing and repairing the lesions of the lateral meniscus. However, there are safety concerns about popliteal artery (PA) injuries during the procedure. This study aimed to assess the safe distance between the trajectory of the LARAI portal and PA.Materials and methodsBoth three-dimensional computed tomography (3D-CT) and cadavers were used to simulate the LARAI portal trajectory. In the 3D-CT study, between January 2020 and September 2020, 45 participants who underwent computed tomography angiography were included in the study. The shortest distance from the PA to the simulated trajectory needle (PS) was measured using 3D-CT. Mean −3SD −2 was calculated to assess the safety of the LARAI portal trajectory. If this value was more than zero, the trajectory was considered “safe.” In the cadaveric study, lower limbs from seven fresh-frozen cadavers were used to establish the “safe” trajectories of the LARAI portal, and the PS was measured.ResultsIn the 3D-CT study, the longest PS (P < 0.001) was found 20 mm lateral to the edge of the patellar tendon trajectory at 0 mm from the posterior cruciate ligament (PCL). Safe trajectories were also found 10 mm, 15 mm, and 20 mm lateral to the edge of the patellar tendon at 0 mm from the PCL, as well as the 20 mm lateral to the edge of the patellar tendon at 3 mm from the PCL. The cadaveric study showed that the average PS of all safe trajectories closely adjoined to PCL was greater than 14 mm.ConclusionsThe LARAI portal trajectory in the “figure of four” is safe, and the optimal insertion point is 10–20 mm lateral to the edge of the patellar tendon and closely adjoined to the posterolateral margin of the PCL at knee joint line level.Level of evidenceLevel IV.

Optimal insertion positions of anterior-posterior orientation sacroiliac screw.

To explore the optimal insertion positions of anterior-posterior orientation sacroiliac screw (AP-SIS). Pelvic CT data of 80 healthy adults were employed to measure the anatomical parameters including the insertable ranges of S1 and S2, the length, width and height of the channel with three different horizontal and vertical anterior insertion points starting from the ilium-acetabular recess. To compare pelvic stability by replicating a type C Tile lesions, fifteen synthetic pelvises were fixed with an anterior plate and a posterior AP-SIS employing different anterior insertion points, the whole specimen displacements and shifts in the sacroiliac gap under a cyclic vertical load of 300 N in a biomechanical machine recorded. The posterior and anterior insertable ranges averaged 17.9 × 8.5mm2 and 47.1 × 21.2 mm2, respectively. The channel lengths for three horizontal anterior insertion points gradually decreased from front to back with significant difference (p < 0.05), whereas the width and height for three horizontal anterior insertion points and the parameters for the three vertical anterior insertion points were similar (p > 0.05). The displacements and shifts for three horizontal insertion points gradually increased from front to back (p < 0.05) whereas the measurements involving the three vertical insertion points were similar (p > 0.05). The posterior insertable range is small, where the center between adjacent nerve roots (foramens) is the optimal posterior insertion point. The anterior insertable range is large, where the iliac-acetabular recess is the optimal anterior insertion point for S1 and S2, providing the longest channel and best stability.

Robotic Tissue Sampling for Safe Post-Mortem Biopsy in Infectious Corpses.

In pathology and legal medicine, the histopathological and microbiological analysis of tissue samples from infected deceased is a valuable information for developing treatment strategies during a pandemic such as COVID-19. However, a conventional autopsy carries the risk of disease transmission and may be rejected by relatives. We propose minimally invasive biopsy with robot assistance under CT guidance to minimize the risk of disease transmission during tissue sampling and to improve accuracy. A flexible robotic system for biopsy sampling is presented, which is applied to human corpses placed inside protective body bags. An automatic planning and decision system estimates optimal insertion point. Heat maps projected onto the segmented skin visualize the distance and angle of insertions and estimate the minimum cost of a puncture while avoiding bone collisions. Further, we test multiple insertion paths concerning feasibility and collisions. A custom end effector is designed for inserting needles and extracting tissue samples under robotic guidance. Our robotic post-mortem biopsy (RPMB) system is evaluated in a study during the COVID-19 pandemic on 20 corpses and 10 tissue targets, 5 of them being infected with SARS-CoV-2. The mean planning time including robot path planning is 5.72±167s. Mean needle placement accuracy is 7.19± 422mm.

Morphometric Evaluation of Second to Fifth Metacarpals for Retrograde Intramedullary Headless Screw Fixation

Intramedullary headless screw fixation has come to the fore in the treatment of metacarpal fractures in recent years with its advantages. Our aim was to evaluate the metacarpal morphometry for retrograde intramedullary entrance and to determine the optimal entry point. Computed tomography images of 105 patients including 64 men and 41 women, were examined. Distal and proximal metacarpal widths, medullary cavity width, cortex thickness and the measurements of the optimal entry site in volar-dorsal and radio-ulnar directions were measured in both coronal and sagittal planes. In the sagittal plane, the second metacarpal had the widest proximal width (16.29 mm), distal width was greatest in the third metacarpal (14.34 mm) which was significantly different between the sexes (p<0.001). Third metacarpal had the widest medullary cavity width in the sagittal plane (4.12 mm). In the coronal plane, it was the second metarcarpal with the widest proximal (16.14 mm) and distal width (13.92 mm) and was also the longest (66.32 mm). Unlike the sagittal plane, the medullary cavity width in the coronal plane was at the widest (4.06 mm) in fifth metacarpal. The points determined for optimal entry were respectively (4.60 mm; 4.97 mm; 4.55 mm; 4.36 mm) in the dorsal-volar plane, close to the dorsal side. There was no significant difference between the sexes for optimal insertion point in the sagittal planes in all the measured metacarpals. Considering its three dimensional structure, metacarpal bones have irregular morphometric properties and these features differ in sagittal and coronal planes. The optimal entry site is located in the midline in the coronal plane, while it is located in the sagittal plane close to the dorsal part. Knowing these properties can reduce the complication rate by reducing entry attempts and help select the correct material.

Pin Insertion to the Interosseous Hood Minimize the Finger Motion Restriction for the Proximal Phalangeal Percutaneous Fixation: A Cadaveric Study.

Background: The purpose of this study was to identify the optimal pin insertion point to minimize finger motion restriction for proximal phalangeal fixation in cadaver models. Methods: We used 16 fingers from three fresh-frozen cadavers (age, 82-86 years). Each finger was dissected at the level of the carpometacarpal joint and fixated to a custom-built range of motion (ROM)-measuring apparatus after skin removal. The pin was inserted into the bone through four gliding soft tissues: the interosseous hood, dorsal capsule, lateral band, and sagittal band. Then, each tendon was pulled by a prescribed weight in three finger positions (flexion, extension, and intrinsic plus position). Changes in the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) angles were measured before and after pinning. We compared the differences between the insertion points using the Tukey-Kramer post hoc test. Results: Placement of pins into the sagittal band significantly restricted MCP joint flexion, while placement into the dorsal capsule and lateral band significantly restricted PIP joint flexion. Only placement into the interosseous hood showed no significant difference in joint angles between the three finger positions compared to pre-pin insertion. There were no significant effects on MCP, PIP, and DIP joint extension. Conclusions: The ROM of the MCP joint was obstructed due to pinning in most areas of insertion. However, pin insertion to the interosseous hood did not obstruct the finger flexion ROM compared to that of other gliding soft tissues; therefore, we believe that the interosseous hood may be a suitable pin insertion point for proximal phalangeal fixation.

DEEP-AD: A Multimodal Temporal Video Segmentation Framework for Online Video Advertising

In this paper, we introduce the DEEP-AD framework, a multimodal advertisement insertion system dedicated to online video platforms. The framework is designed from the viewer's perspective, in terms of commercial contextual relevance and degree of intrusiveness. The main contribution of the paper concerns a novel multimodal temporal video segmentation algorithm into scenes/stories, which makes it possible to determine automatically the temporal instants that are the most appropriate for inserting advertisement clips. The proposed algorithm exploits various deep convolutional neural networks, involved at several stages. The video stream is first divided into shots based on a graph partition method. The video shots are then clustered into scenes/story units with the help of an agglomerative clustering methodology taking as input visual, audio and semantic features. Furthermore, in order to facilitate the user's access to multimedia documents a novel thumbnail extraction method is proposed based on both semantic representativeness and visual quality information. Finally, the optimal advertisement insertion points are determined based on the ads temporal distribution, commercial diversity and degree of intrusiveness. The experimental results, carried out on a large dataset of more than 30 videos, taken from the French National Television and US TV series validate the proposed methodology with average accuracy and recognition rates superior to 88%. Moreover, when compared with other state of the art methods, the proposed temporal video segmentation yields gains of more than 6% in precision and recall rates.

The \u201ccoracoid tunnel view\u201d: a simulation study for finding the optimal screw trajectory in coracoid base fracture fixation

PurposeCoracoid fractures represent approximately 3–13% of all scapular fractures. Open reduction and internal fixation can be indicated for a coracoid base fracture. This procedure is challenging due to the nature of visualization of the coracoid with fluoroscopy. The aim of this study was to develop a fluoroscopic imaging protocol, which helps surgeons in finding the optimal insertion point and screw orientation for fixations of coracoid base fractures, and to assess its feasibility in a simulation study.MethodsA novel imaging protocol was defined for screw fixation of coracoid base fractures under fluoroscopic guidance. The method is based on finding the optimal view for screw insertion perpendicular to the viewing plane. In a fluoroscopy simulation environment, eight orthopaedic surgeons were invited to place a screw down the coracoid stalk through the coracoid base and into the neck of 14 cadaveric scapulae using anatomical landmarks. The surgeons placed screws before and after they received an e-learning of the optimal view. Results of the two sessions were compared and inter-rater reliability was calculated.ResultsScrew placement was correct in 33 out of 56 (58.9%) before, and increased to 50 out of 56 (89.3%) after the coracoid tunnel view was explained to the surgeons, which was a significant improvement (p < 0.001).ConclusionsOur newly developed fluoroscopic view based on simple landmarks is a useful addendum in the orthopaedic surgeon’s tool box to fixate fractures of the coracoid base.

Optimal Point of Insertion and Needle Angle in Neuraxial Blockade Using a Midline Approach

(Reg Anesth Pain Med. 2017;42(5):600–608) When using a midline approach to neuraxial blockade, as few attempts as possible should be made to ensure patient comfort and reduce the risk of complications. This approach can be difficult, however, due to both patient factors beyond the clinician’s control as well as equipment used, clinician experience, the positioning of the patient, and point of insertion. While there are suggested needle insertion points and angles, none are supported by clinical research. This study aimed to establish a scientific rationale for choosing the optimal insertion angle and insertion point for access to the subarachnoid space or the epidural space by using a computer algorithm to perform measurements in computed tomography (CT) scans in 52 patients at different spine levels.

Intraoperative sonography may reduce the risk of extensor pollicis longus tendon injury during dorsal entry elastic intramedullary nailing of the radius in children

Extensor pollicis longus tendon (EPL) injury is a potential complication of dorsal entry radial elastic nailing technique in children. The aim of this study was to investigate if intraoperative ultrasonographic guidance can reduce the risk of (EPL) injury.Correlation between sonographic and operative findings were examined first in 6 adult cadavers. Position of Lister's tubercle, EPL, and extraosseal end of the elastic nail were detected by ultrasound imaging during a minimally invasive dorsal entry nailing. Radial slope of Lister's eminence was determined as a safe and easily identifiable entry point for opening the medullary canal. Extraosseal ends of the nails were bended in a slight radial direction and cut immediately beneath the skin in a maximally palmar-flexed wrist position. Cadaveric dissections followed our procedures all correlated with ultrasonographic findings, we have not seen tendon damage, obstruction or friction by the implant's end.After cadaveric experiments, we began using intraoperative sonography for monitoring elastic nail insertion in pediatric radial fractures.Between January 2015 and November 2016, 77 pediatric closed diaphyseal radial fractures were operated by dorsal approach ESIN under intraoperative sonographic checking.Procedures were executed by 2 orthopedic surgeons experienced in ESIN technique with basic musculoskeletal ultrasonographic qualifications.Sonographic identification of EPL and Lister's tubercle in the transverse view was possible in all cases. Determination of the position of the nail end to EPL was also possible in all cases. Mean distance of the transverse view center of the EPL and nail was 0.49 cm (range 0.3–0.62 cm, SD = 0.66). Based on the sonographic transverse view, the operator decided repositioning the nails by 2 patients.We have not found EPL injury postoperatively. All patients were followed for at least 12 months after operations. Nails were removed in all children without further complications.Intraoperative sonography helps determining optimal insertion point and the risk of EPL injury may be reduced during dorsal entry approach.Although the procedure is relatively easy, authors take note that surgical and sonoanatomic knowledge, basic sonographic skills and experience in the ESIN technique are equally necessary for its successful application. A greater number of cases is necessary to confirm our initial promising experiences.

Assessment of the Isometry of the Anterolateral Ligament in a 3-Dimensional Weight-Bearing Computed Tomography Simulation

To simulate the most isometric insertion points of the anterolateral ligament (ALL) in a weight-bearing 3-dimensional computed tomography (CT) model using previously published anatomic landmarks and to define radiographic landmarks, which make for an easier identification of the optimal insertion points. The most isometric femoral insertion points were analyzed for 10 individuals, using data of weight-bearing CT scans in increasing knee flexion positions. An automatic string generation algorithm helped identify isometrically optimal points using an isometric score (0 indicating optimal isometry). Subsequently, a general femoral insertion point was determined, which preserved the isometry in all tested individuals. Based on the femoral insertion point, we assessed the influence of varying tibial insertion points on the isometric behavior of the ALL. The defined femoral insertion point, which preserved the isometry in all analyzed individuals, had a median isometric score between 0.167× 10-3 and 0.559× 10-3. The average distance from the most prominent point of the lateral epicondyle was 9.7mm (standard deviation [SD], 1.6) in a straight superior direction. In a straight lateral radiographic view, this point is located exactly at the intersection of a tangent set between the posterior cortex of the femur and a second perpendicular line intersecting at the level of the most (superior-) posterior point of the Blumensaat line. The best isometric behavior was found on the anatomically defined mean tibial insertion point, located at 37% of the width of the tibial plateau, which worsened gradually if corrected to anterior or posterior. We determined femoral and tibial insertion points as well as radiographic landmarks for the reconstruction of the ALL that are based on published anatomic descriptions and preserve isometry in all analyzed individuals in this study. This study provides new information, which might be helpful to define isometrically optimal insertion points for ALL reconstruction.

Computed Tomographic Analysis of Ventral Atlantoaxial Optimal Safe Implantation Corridors in 27 Dogs.

Objectives Ventral atlantoaxial stabilization techniques are challenging surgical procedures in dogs. Available surgical guidelines are based upon subjective anatomical landmarks, and limited radiographic and computed tomographic data. The aims of this study were (1) to provide detailed anatomical descriptions of atlantoaxial optimal safe implantation corridors to generate objective recommendations for optimal implant placements and (2) to compare anatomical data obtained in non-affected Toy breed dogs, affected Toy breed dogs suffering from atlantoaxial instability and non-affected Beagle dogs. Methods Anatomical data were collected from a prospectively recruited population of 27 dogs using a previously validated method of optimal safe implantation corridor analysis using computed tomographic images. Results Optimal implant positions and three-dimensional numerical data were generated successfully in all cases. Anatomical landmarks could be used to generate objective definitions of optimal insertion points which were applicable across all three groups. Overall the geometrical distribution of all implant sites was similar in all three groups with a few exceptions. Clinical Significance This study provides extensive anatomical data available to facilitate surgical planning of implant placement for atlantoaxial stabilization. Our data suggest that non-affected Toy breed dogs and non-affected Beagle dogs constitute reasonable research models to study atlantoaxial stabilization constructs.

Femoral insertion site in medial patellofemoral ligament reconstruction

BackgroundThe optimal femoral insertion point in MPFL (medial patellofemoral ligament)-reconstruction still remains ambiguous. Three-dimensional knee simulations based on computerized tomography (CT) images acquired under physiological loading conditions give further insights to predict the optimal femoral insertion site of the MPFL.The hypothesis of the present study is that the optimal insertion point is not as reliable as thought and is dependent on subject-specific anatomical factors. MethodsHigh-resolution 3D images of the knee were acquired in ten weight-bearing knees of healthy subjects in five flexion angles (0 to 120°). The distance between different femoral insertion points and two defined patellar points was computed in each position to quantify length of respective bundles and isometry of the femoral insertion site. ResultsThe median length of both bundles was maximal in full extension (proximal bundle: 62.2mm and distal bundle: 59.9mm). The shortest ligament length was obtained in the flexion position 90° for bundle I (57.3mm) and 30° for bundle II (85.3mm).The calculated most isometric femoral attachment point showed a non-uniform distribution pattern related to anatomic landmarks. The radiographic landmark showed the worst isometric score value compared to virtually defined spots by surgeons and the computed most isometric point. ConclusionsThis study provides results on the MPFL path length under physiological loading conditions using high-resolution bone geometry.The most important finding of this study was that the computed, best isometric femoral insertion point showed a variable anatomical distribution. This suggests that the optimal position for femoral MPFL-graft fixation is patient specific.

Computed tomography assisted determination of optimal insertion points and bone corridors for transverse implant placement in the feline tarsus and metatarsus.

Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus. Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA). Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor. Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.

Computed Tomography (CT) Simulated Fluoroscopy-Guided Transdiscal Approach in Transcrural Celiac Plexus Block

Conventional transcrural CPB via the "walking off" the vertebra technique may injure vital organs while attempting to proximally spread injectate around the celiac plexus. Therefore, we attempted the CT-simulated fluoroscopy-guided transdiscal approach to carry out transcrural CPB in a safer manner, spreading the injectate more completely and closely within the celiac plexus area. A 54-year-old male patient with pancreatic cancer suffered from severe epigastric pain. The conventional transcrural approach was simulated, but the needle pathway was impeded by the kidney on the right side and by the aorta on the left side. After simulating the transdiscal pathway through the T11-12 intervertebral disc, we predetermined the optimal insertion point (3.6 cm from the midline), insertion angle (18 degrees), and advancement plane, as well as the proper depth. With the transdiscal approach, we successfully performed transcrural CPB within a narrow angle, and the bilateral approach was not necessary as we were able to achieve the bilateral spread of the injectate with the single approach.

Echo-guided estimation of formula for paravertebral block in neonates, infants and children till 5 years

Aims:The aim of the study was to derive a clinically useful formula for paravertebral block for thoracic, lumbar (L1) and cervical level (C6) as per the ultrasound-guided measurements in neonates, infants and children up to 5 years of age.Settings and Design:Observational study.Methods:Seventy-five patients from 2 days to 60 months were included. Paravertebral transverse ultrasound scans at cervical (C6), thoracic (T1-12) and lumbar (L1) regions were viewed to determine the optimal insertion point and depth for performing paravertebral blocks. The lateral distance from the spinous process to the insertion point and the depth from the insertion point to the paravertebral space or reference point (point just anterior to the transverse process) were measured.Statistical Analysis:Data was analyzed using the SPSS (V 10.0) package. Preliminary data was collected with the actual values of paravertebral parameters and weight and age. Initially, Pearson Bivariate Correlation Coefficients were calculated between parameters and age and weight so as to predict paravertebral parameters with the help of weight and age. As there were statistically significant associations between parameters and age and weight, an attempt was made to predict parameters with the help of age and weight. Multiple regression method (forward) was applied by taking parameters as dependent variables and age and weight as independent variables.Results:Age and weight correlated very well (statistically significant) with paravertebral parameters; hence, prediction (regression) equations were calculated as:Prediction (regression) equation:C6A=0.005 × wt + 0.005 × age + 1.31C6B=0.009 × wt + 0.002 × age + 1.78T1-12 A=0.02 × wt + 0.003 × age + 0.93T1 to 12 B=0.03 × wt + 0.03 × age + 1.02L1A=0.03 × wt + 0.02 × age + 0.91L1B=0.05 × wt + 0.02 × age + 0.94Conclusions:We could derive equations to predict the values for paravertebral blocks in centimetres at different levels in the study population.

All-arthroscopic intramedullary nailing of 2- and 3-part proximal humeral fractures: a new arthroscopic technique and preliminary results

The most criticism of antegrade humeral nailing is the potentially deleterious effect on the shoulder function, which is caused by the trauma to the M. supraspinatus (SSP) at the nail insertion site. We describe a new technique of all-arthroscopical intramedullary nailing, which preserves the rotator cuff, and compare it with the conventional open procedure. From 11/2009 to 12/2010 82 patients with unstable, displaced proximal humeral fractures were treated surgically. Twenty-one of these patients received an intramedullary nailing. Sixteen of 21 met the inclusion criteria. Based on the surgeon's arthroscopic experience, patients were assigned to the arthroscopic (group I, n = 8) or open group (group II, n = 8). Both groups were compared due to the replacement results, complications, time of surgery and fluoroscopy. Concomitant intraarticular pathologies were assessed (group I). First clinical results after a median follow-up of 13 months (group I) and 14 months (group II) were reported. Between group I and II, no significant differences were seen in patients age [77 years (range 45-90 years) vs. 76 years (range 65-92 years)], gender (6 female/2 male vs. 5 female/3 male) and fracture pattern (six 2-/two 3-part fractures vs. five 2-/three 3-part fractures). The reduction was evaluated by the caput-diaphysis-angle, which was median 137° (range 120-147°) in group I and 132° (range 120-158°) in group II (p = 0.959). Postoperatively, group I showed one varus-, group II two varus- and valgus deformities. Median time of surgery was 75 min (range 45-182 min) versus 70 min (range 40-146 min) (p = 0.442), fluoroscopy time 1.5 min (range, 0.6-3.7 min) versus 1.2 min (range 0.3-2.2 min) in group I and II (p = 0.336). Concomitant pathologies like one traumatic bicipital tendon-lesion and three partial lesions of the SSP were observed and treated in group I. Constant Scores and Visual Analogue Scale did not differ significantly between both groups at the time of follow-up. All-arthroscopical humeral nailing is possible, preserves the rotator cuff and provides equal replacement and functional results like the open technique. An arthroscopically visualized optimal nail insertion point provides less frequent head deformities. Level of evidence Level III.

Ultrasound simulation of internal jugular vein cannulation in pregnant and non-pregnant women

Pregnancy alters the anatomic landmarks for internal jugular vein (IJV) cannulation. In this study, IJV cannulation was simulated, and success of the technique was evaluated using ultrasound. Term pregnant women and non-pregnant female volunteers were recruited. The degree of difficulty in assessing neck anatomy was noted. The optimal insertion points for cannulation were marked on the skin of each subject according to the central landmark and palpatory techniques. The midpoint of a 15-10MHz linear transducer was placed over each insertion point, and the vertical cursor of the ultrasound, which represented the path of the needle, was placed in the image. The outcome was an IJV puncture, a carotid artery (CA) puncture, or a missed attempt. One hundred and sixty-one women, 99 pregnant and 62 non-pregnant, were studied. The identification of landmarks was more difficult in pregnant women (P=0.01). The rates of successful IJV punctures, CA punctures, and missed attempts did not differ significantly between pregnant and non-pregnant women. Carotid artery punctures using the central landmark technique in pregnant and non-pregnant subjects were 19% and 10%, respectively. Corresponding figures for the palpatory approach were 6% and 3%, respectively. The degree of IJV overlap of the CA in the palpatory technique was greater in pregnant women (38% vs 18% showed>75% overlap; P<0.001), a difference that remained after controlling for body mass index The IJV overlies the CA to a greater extent in pregnant patients than in non-pregnant patients. Thus, a landmark approach for IJV cannulation might expose pregnant women to a greater risk of carotid puncture. This trial was registered at www.clinicaltrials.gov (NCT T00464828).