Preoperative Motion Planner for Steerable Needles Using Cost Map Based on Repulsive Field and Empirical Model of Needle Deflection

Needle insertion is a common procedure in percutaneous puncture. A motion planner for a steerable needle that considers the risk level of the path in anatomical environment and the actual deflection of clinical needle is necessary. A novel preoperative motion planner for a steerable needle controlled by robot is proposed. Our method utilizes sampling-based planner to compute candidate path in the reachable region, the path solutions are optimized by calculating the cost of a path based on a cost map. The cost-map, which is built based on repulsive field theory from CT image, encodes the information of the obstacle locations and the criticality of the anatomical environment. The empirical formula that can predict needle trajectory is obtained by insertion experiments. Experiments shown that positioning error in gelatin phantom under the guidance of our planner is less than 1.1mm. Comparing with the straight-line insertion method, the positioning error was reduced by 80%. The results indicate that the motion planner has the potential to provide effective guidance for robot-assisted puncture surgery while enhancing the position precision and patient safety.

USG SAVED THE DAY: PRE-PROCEDURAL USG SPINE FOR SPINAL ANAESTHESIA IN A PARTURIENT WITH THORACO-LUMBAR SCOLIOSIS WITH POST BURN CONTRACTURE NECK

Introduction: Incidence of Scoliosis is approximately 2% and higher in females. Therefore, anaesthesiologist should be familiar with its implications for safe anaesthetic management1. Such parturients present unique challenges for administration of regional anaesthesia. Reporting one such case with a successful outcome using pre procedural Ultrasound spine for spinal anaesthesia. A 27 years, 39 weeks Case Report: primigravida of height 132 cm, with cephalo pelvic disproportion in labour with grade III scoliosis and post burn contractures involving neck, was posted for emergency cesarean section. Patient underwent surgery successfully under SAB after accessing spine by ultrasonography for identifying point of insertion, depth of intrathecal space & needle trajectory.2 Ultrasound is Conclusion: boon for accessing spine in patient with difcult spinal anatomy and pregnancy for deciding correct spinal interspace and successful outcome with fewer attempts.

A row-generation approach for simultaneous multiple needle trajectory planning in radiofrequency ablation

Radiofrequency ablation is a thermal therapy for moderately-sized cancerous tumors. A target is killed with high temperatures obtained due to the current passed through one or more electrodes (needles) inserted into it. The needles' trajectory must be meticulously planned to prevent interference with dense organs like bone or puncturing of critical structures like veins. By approximating the thermal lesion to an ellipse, we predefine several valid needle trajectories and then solve an integer programming model to identify pairwise valid needle positions, that meet clinical criteria, using a variation of the classic set cover model. To improve the models' tractability and scalability, we use row generation-based decomposition techniques that determines pairwise validity using two different types of cuts. Finally, we analyze target and OAR damage using several thermal damage models. Thus, for the first time we present a full treatment plan that incorporates novel trajectory planning with thermal dose computations. Our method is tested on 12 liver targets: three targets each with four different surgical margins. We show promising results that meet clinical guidelines while obtaining full target coverage.

A Novel Ultrasound-guided With Needle Visualization Pericardiocentesis Via Subcostal Approach

Cardiac tamponade is a condition when fluids or blood fill the pericardial space resulting in compression of the heart and subsequently compromising hemodynamic status of the patient. It is a potentially fatal medical or traumatic emergency that requires rapid recognition and immediate treatment. Formerly, blind or surgical techniques were used to aspirate the pericardial fluid and they were associated with plenty of risks and complications. In the recent era, medical technology development has enabled us to perform the procedure safely with the assistance of ultrasound devices. The ultrasound-guided procedure is not only proven to be effective and safe, but it also has very minimal drawbacks and complications. In the literature, there are many ultrasound-guided pericardiocentesis procedures performed with different approaches at different regions. They include subcostal, parasternal, and para-apical approaches and phased array echocardiography transducers are typically preferred for the procedures. We report a case of cardiac tamponade presented with hemodynamic compromise. Ultrasound-guided pericardiocentesis was carried out using in-plane technique with high frequency linear ultrasound transducer at the subcostal region as lifesaving procedure. This particular technique provided full visualization of needle trajectory throughout the procedure. It was successfully completed with no complications and patient’s hemodynamic status improved post-procedure. This article highlights the novel use of in-plane method with high frequency linear transducer at subcostal area as a safe option for pericardiocentesis in patients with cardiac tamponade.

Optimization-Based Constrained Trajectory Generation for Robot-Assisted Stitching in Endonasal Surgery

The reduced workspace in endonasal endoscopic surgery (EES) hinders the execution of complex surgical tasks such as suturing. Typically, surgeons need to manipulate non-dexterous long surgical instruments with an endoscopic view that makes it difficult to estimate the distances and angles required for precise suturing motion. Recently, robot-assisted surgical systems have been used in laparoscopic surgery with promising results. Although robotic systems can provide enhanced dexterity, robot-assisted suturing is still highly challenging. In this paper, we propose a robot-assisted stitching method based on an online optimization-based trajectory generation for curved needle stitching and a constrained motion planning framework to ensure safe surgical instrument motion. The needle trajectory is generated online by using a sequential convex optimization algorithm subject to stitching kinematic constraints. The constrained motion planner is designed to reduce surrounding damages to the nasal cavity by setting a remote center of motion over the nostril. A dual concurrent inverse kinematics (IK) solver is proposed to achieve convergence of the solution and optimal time execution, in which two constrained IK methods are performed simultaneously; a task-priority based IK and a nonlinear optimization-based IK. We evaluate the performance of the proposed method in a stitching experiment with our surgical robotic system in a robot-assisted mode and an autonomous mode in comparison to the use of a conventional surgical tool. Our results demonstrate a noticeable improvement in the stitching success ratio in the robot-assisted mode and the shortest completion time for the autonomous mode. In addition, the force interaction with the tissue was highly reduced when using the robotic system.

Steerable Needle Trajectory Following in the Lung: Torsional Deadband Compensation and Full Pose Estimation With 5DOF Feedback for Needles Passing Through Flexible Endoscopes

Bronchoscopic diagnosis and intervention in the lung is a new frontier for steerable needles, where they have the potential to enable minimally invasive, accurate access to small nodules that cannot be reliably accessed today. However, the curved, flexible bronchoscope requires a much longer needle than prior work has considered, with complex interactions between the needle and bronchoscope channel, introducing new challenges in steerable needle control. In particular, friction between the working channel and needle causes torsional windup along the bronchoscope, the effects of which cannot be directly measured at the tip of thin needles embedded with 5 degree-of-freedom magnetic tracking coils. To compensate for these effects, we propose a new torsional deadband-aware Extended Kalman Filter to estimate the full needle tip pose including the axial angle, which defines its steering direction. We use the Kalman Filter estimates with an established sliding mode controller to steer along desired trajectories in lung tissue. We demonstrate that this simple torsional deadband model is sufficient to account for the complex interactions between the needle and endoscope channel for control purposes. We measure mean final targeting error of 1.36 mm in phantom tissue and 1.84 mm in ex-vivo porcine lung, with mean trajectory following error of 1.28 mm and 1.10 mm, respectively.

Fluoroscopically guided mandibular nerve block: a modified lateral approach

Background and objectivesMandibular nerve blocks are indicated for atypical face pain and trigeminal neuralgia. We hypothesized that a modified lateral approach, which entailed a combination of lateral and anterior approach techniques to the mandibular nerve block would lead to similar efficacy and improved safety profile rather than the typical lateral or anterior techniques.MethodsThis alternative approach was derived from anatomical investigation using the Radiology Anatomy Atlas Viewer and reconstructed axial cadaveric slices. We used axial slices at the level of the lateral pterygoid plate, and at the level of the temporomandibular joint to devise a needle path appropriate for this block.ResultsThe modified lateral approach to the mandibular nerve block was verified theoretically through cadaveric reconstructed slices and has been successfully performed in our practice. Precise needle trajectory could avoid both periosteal contact and gross redirection, as well as other procedural complications.ConclusionThe modified lateral approach to a mandibular nerve block avoids the respective risks associated with either the lateral and anterior approach. Facial intervention techniques typically pose increased safety challenges, however through cadaveric anatomic reconstruction, we have developed a safer approach for mandibular nerve blockade.

Sciatic, Femoral, and Lateral Femoral Cutaneous Nerve Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation

Objective With advances in peripheral nerve stimulation technology, there has been an emergence of new minimally invasive techniques to provide neurostimulation therapies for chronic pain. This technical note describes the utilization of ultrasonography for percutaneous placement of peripheral nerve stimulation leads at the sciatic, femoral, and lateral femoral cutaneous nerves. Methods Ultrasound can be utilized to localize a specific nerve, view neighboring soft tissue anatomy, and plan a needle trajectory. Various ultrasound techniques and transducer orientations allow for multiple options for lead placement relative to the targeted nerve. Conclusions The option of ultrasound-guided percutaneous technique for neurostimulation lead placement allows this treatment modality to be made available to more patients with chronic pain in specific nerve distributions.