Navigated laparoscopy – liver shift and deformation due to pneumoperitoneum in an animal model

Abstract

Background: Precise laparoscopic liver resection requires accurate planning and visualization of important anatomy such as vessels and tumors. Combining laparoscopic ultrasound with navigation technology could provide this. Preoperative images are valuable for planning and overview of the procedure, while intraoperative images provide an updated view of the surgical field. Purpose: To validate the accuracy of navigation technology based on preoperative images, we need to understand how much the liver shifts and deforms due to heartbeat, breathing, surgical manipulation and pneumoperitoneum. In this study, we evaluated liver tumor shift and deformation due to pneumoperitoneum in an animal model. Methods: Tumor models were injected into the liver of the animal, and 3D CT images were acquired before and after insufflation. Tumor shifts and deformation were determined. Results: The results showed significant tumor position shift due to pneumoperitoneum, with a maximum of 28 mm in cranio-caudal direction. No significant tumor deformation was detected. Small standard deviations suggest rigid body transformation of the liver as a whole, but this needs further investigation. Conclusion: The findings indicate a need for anatomic shift correction of preoperative images before they are used in combination with LUS guidance during a laparoscopic liver resection procedure.     

A novel platform for electromagnetic navigated ultrasound bronchoscopy (EBUS)

Purpose

Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) of mediastinal lymph nodes is essential for lung cancer staging and distinction between curative and palliative treatment. Precise sampling is crucial. Navigation and multimodal imaging may improve the efficiency of EBUS-TBNA. We demonstrate a novel EBUS-TBNA navigation system in a dedicated airway phantom.

Methods

Using a convex probe EBUS bronchoscope (CP-EBUS) with an integrated sensor for electromagnetic (EM) position tracking, we performed navigated CP-EBUS in a phantom. Preoperative computed tomography (CT) and real-time ultrasound (US) images were integrated into a navigation platform for EM navigated bronchoscopy. The coordinates of targets in CT and US volumes were registered in the navigation system, and the position deviation was calculated.

Results

The system visualized all tumor models and displayed their fused CT and US images in correct positions in the navigation system. Navigating the EBUS bronchoscope was fast and easy. Mean error observed between US and CT positions for 11 target lesions (37 measurements) was \(2.8\pm 1.0\) mm, maximum error was 5.9 mm.

Conclusion

The feasibility of our novel navigated CP-EBUS system was successfully demonstrated. An EBUS navigation system is needed to meet future requirements of precise mediastinal lymph node mapping, and provides new opportunities for procedure documentation in EBUS-TBNA.

     

Laparoscopic ultrasound procedure can reduce residual myomas in laparoscopic myomectomy for multiple myomas

Purpose

To clarify whether the use of laparoscopic ultrasound (LUS) during laparoscopic myomectomy could reduce the number of residual myomas after surgery.

Methods

A cohort study was conducted. Subjects were women who underwent laparoscopic myomectomy for multiple uterine myomas for the first time. The subjects were assigned to one of two groups: LUS group or non-LUS group. All subjects underwent pelvic MRI 3 months before and 6 months after surgery, and the number of myomas on MRI was counted by radiodiagnosticians. The extraction rate and residual rate of uterine myomas were compared between the two groups.

Results

Fourteen cases with and 30 cases without LUS were analyzed. Median operation times were 171 min (range 75–295) and 141 min (range 50–260) in cases with and without LUS, respectively (p = 0.077). Median extraction rates relative to the total number of myomas were 106 % (range 75–147 %) in subjects with LUS and 100 % (range 71–233 %) in subjects without LUS (p = 0.480). Numbers of residual myomas were 1 (range 0–3) in subjects with LUS and 2 (range 0–9) in subjects without LUS (p = 0.028). Median residual rates of myomas were 6.1 % (range 0–20 %) in subjects with LUS and 20.0 % (range 0–69 %) in subjects without LUS (p = 0.048). Myomas greater than 3 cm in diameter were not observed in either group.

Conclusions

The number and residual rate of myomas were significantly less in subjects with LUS as compared with those without LUS.

     

Clinical application of a surgical navigation system based on virtual laparoscopy in laparoscopic gastrectomy for gastric cancer

Purpose

Knowledge of the specific anatomical information of a patient is important when planning and undertaking laparoscopic surgery due to the restricted field of view and lack of tactile feedback compared to open surgery. To assist this type of surgery, we have developed a surgical navigation system that presents the patient’s anatomical information synchronized with the laparoscope position. This paper presents the surgical navigation system and its clinical application to laparoscopic gastrectomy for gastric cancer.

Methods

The proposed surgical navigation system generates virtual laparoscopic views corresponding to the laparoscope position recorded with a three-dimensional (3D) positional tracker. The virtual laparoscopic views are generated from preoperative CT images. A point-based registration aligns coordinate systems between the patient’s anatomy and image coordinates. The proposed navigation system is able to display the virtual laparoscopic views using the registration result during surgery.

Results

We performed surgical navigation during laparoscopic gastrectomy in 23 cases. The navigation system was able to present the virtual laparoscopic views in synchronization with the laparoscopic position. The fiducial registration error was calculated in all 23 cases, and the average was 14.0 mm (range 6.1–29.8).

Conclusion

The proposed surgical navigation system can provide CT-derived patient anatomy aligned to the laparoscopic view in real time during surgery. This system enables accurate identification of vascular anatomy as a guide to vessel clamping prior to total or partial gastrectomy.

     

Improved surgical procedure using intraoperative navigation for the implantation of the SPG microstimulator in patients with chronic cluster headache

Introduction

The ATI SPG microstimulator is designed to be fixed on the posterior maxilla, with the integrated lead extending into the pterygopalatine fossa to electrically stimulate the sphenopalatine ganglion (SPG) as a treatment for cluster headache. Preoperative surgical planning to ensure the placement of the microstimulator in close proximity (within 5 mm) to the SPG is critical for treatment efficacy. The aim of this study was to improve the surgical procedure by navigating the initial dissection prior to implantation using a passive optical navigation system and to match the post-operative CBCT images with the preoperative treatment plan to verify the accuracy of the intraoperative placement of the microstimulator.

Methods

Custom methods and software were used that result in a 3D rotatable digitally reconstructed fluoroscopic image illustrating the patient-specific placement with the ATI SPG microstimulator. Those software tools were preoperatively integrated with the planning software of the navigation system to be used intraoperatively for navigated placement. Intraoperatively, the SPG microstimulator was implanted by completing the initial dissection with CT navigation, while the final position of the stimulator was verified by 3D CBCT. Those reconstructed images were then immediately matched with the preoperative CT scans with the digitally inserted SPG microstimulator. This method allowed for visual comparison of both CT scans and verified correct positioning of the SPG microstimulator.

Results

Twenty-four surgeries were performed using this new method of CT navigated assistance during SPG microstimulator implantation. Those results were compared to results of 21 patients previously implanted without the assistance of CT navigation. Using CT navigation during the initial dissection, an average distance reduction of 1.2 mm between the target point and electrode tip of the SPG microstimulator was achieved. Using the navigation software for navigated implantation and matching the preoperative planned scans with those performed post-operatively, the average distance was 2.17 mm with navigation, compared to 3.37 mm in the 28 surgeries without navigation.

Conclusion

Results from this new procedure showed a significant reduction (p = 0.009) in the average distance from the SPG microstimulator to the desired target point. Therefore, a distinct improvement could be achieved in positioning of the SPG microstimulator through the use of intraoperative navigation during the initial dissection and by post-operative matching of pre- and post-operatively performed CBCT scans.

     

Serial Transthoracic Ultrasonography Studies in Hematopoietic Cell Transplant Patients: A Tool for Early Lung Pathology Detection

Early detection of pulmonary complications can improve outcomes for patients with hematological malignancy (HM). For detecting lung injuries, lung ultrasound (LUS) images have been found to be of greater sensitivity than radiographic images. Our group performed a pilot study of LUS imaging to enhance early detection of pulmonary complications in HM patients. This prospective single-center feasibility study evaluated LUS for detecting pulmonary complications in 18 HM patients enrolled while hospitalized for a hematopoietic cell transplant (HCT) (concurrent-HCT group) or re-hospitalized for complications (post-HCT group). Serial LUS exams were performed and assigned a score from 0 to 5 based on pleural line, B-line, consolidation and pleural effusion features. Correlations between patients’ clinical characteristics and LUS features were analyzed. Comparisons between the LUS and radiographic images were evaluated. In the concurrent-HCT patients (79 LUS exams), non-significant fluctuating findings were commonly identified, but one-third of the patients presented pathologic findings (LUS scores ≥ 3). In the post-HCT patients (29 LUS exams), LUS images revealed severe pathologic findings (LUS score = 5) in every patient and, compared with radiographic images, were more sensitive for detecting pleural effusions (p < 0.05). LUS can be routinely performed on hospitalized HM patients, allowing point-of-care early detection of pulmonary complications.     

Integration of lung ultrasound in the diagnostic reasoning in acute dyspneic patients: A prospective randomized study

Introduction

Misdiagnosis in acute dyspneic patients (ADP) has consequences on their outcome. Lung ultrasound (LUS) is an accurate tool to improve diagnostic performance. The main goal of this study was to assess the determinants of increased diagnostic accuracy using LUS.

Towards real time 2D to 3D registration for ultrasound-guided endoscopic and laparoscopic procedures

Purpose  

A method to register endoscopic and laparoscopic ultrasound (US) images in real time with pre-operative computed tomography (CT) data sets has been developed with the goal of improving diagnosis, biopsy guidance, and surgical interventions in the abdomen.     

肺部超声在评估新生儿呼吸窘迫综合征治疗效果中的应用

目的探讨肺部超声（LUS）在评估新生儿呼吸窘迫综合征（NRDS）使用肺表面活性物质（PS）治疗效果中的临床价值。 方法前瞻性选取2018年5月至2018年12月于空军军医大学唐都医院新生儿重症监护室（NICU）收治的NRDS患儿共37例，依据临床是否应用PS治疗分为2组，其中治疗组27例，选用猪肺磷脂注射液（固尔苏）经气管插管给药；对照组10例，不使用任何PS治疗。2组患儿在入组后均行LUS检查，观察超声图像特征并进行评分，治疗组另分别观察治疗后4 h、1 d、3 d超声图像及评分变化。 结果对照组LUS评分显著低于治疗组（11.20±2.10 vs 20.59±5.46），2组比较差异有统计学意义（t=-7.561，P<0.001）。治疗组在使用固尔苏治疗不同时间点LUS评分比较差异有统计学意义（F=30.453，P<0.001），其中治疗组在使用固尔苏治疗后4 h与治疗前相比，LUS评分明显下降（14.30±4.79 vs 20.59±5.46），2者比较差异有统计学意义（P<0.001）；治疗后1 d与治疗后4 h比较，LUS评分差异无统计学意义（P=0.389）；治疗后3 d相较于治疗后1 d，LUS评分差异无统计学意义（P=0.136）；治疗后3 d与治疗后4 h相比，LUS评分显著降低（9.12±3.45 vs 14.30±4.79），2者比较差异有统计学意义（P=0.001）。对照组LUS图像表现为轻度肺泡间质综合征，治疗组表现为"白肺"及肺实变，固尔苏治疗4 h后"白肺"变为稀疏B线，肺实变范围明显缩小。 结论LUS可以早期预测NRDS患儿是否需要应用固尔苏进行治疗，并实时监测治疗效果，为NRDS患儿的临床用药和治疗监测提供重要信息和依据。     

Patient navigation moderates emotion and information demands of cancer treatment: a qualitative analysis

Purpose

Patient navigation is increasingly employed to guide patients through cancer treatment. We assessed the elements of navigation that promoted patients’ involvement in treatment among patients with breast and colorectal cancer that participated in a navigation study.

Methods

We conducted qualitative analysis of 28 audiotaped and transcribed semi-structured interviews of navigated and unnavigated cancer patients.

Results

Themes included feeling emotionally and cognitively overwhelmed and desire for a strong patient-navigator partnership. Both participants who were navigated and those who were not felt that navigation did or could help address their emotional, informational, and communicational needs. The benefits of logistical support were cited less often.

Conclusions

Findings underscore the salience of personal relationships between patients and navigators in meeting patients’ emotional and informational needs.     

Auditory feedback to support image-guided medical needle placement

Purpose

During medical needle placement using image-guided navigation systems, the clinician must concentrate on a screen. To reduce the clinician’s visual reliance on the screen, this work proposes an auditory feedback method as a stand-alone method or to support visual feedback for placing the navigated medical instrument, in this case a needle.

Methods

An auditory synthesis model using pitch comparison and stereo panning parameter mapping was developed to augment or replace visual feedback for navigated needle placement. In contrast to existing approaches which augment but still require a visual display, this method allows view-free needle placement. An evaluation with 12 novice participants compared both auditory and combined audiovisual feedback against existing visual methods.

Results

Using combined audiovisual display, participants show similar task completion times and report similar subjective workload and accuracy while viewing the screen less compared to using the conventional visual method. The auditory feedback leads to higher task completion times and subjective workload compared to both combined and visual feedback.

Conclusion

Audiovisual feedback shows promising results and establishes a basis for applying auditory feedback as a supplement to visual information to other navigated interventions, especially those for which viewing a patient is beneficial or necessary.

     

Recovery of respiratory motion and deformation of the liver using laparoscopic freehand 3D ultrasound system

The present paper describes a method for intraoperative recovery of respiratory motion and deformation of the liver by using a laparoscopic freehand 3D ultrasound (US) system. The proposed method can extend 3D US data of the liver to 4D by acquiring additional several sequences of time-varying 2D US images during a couple of respiration cycles. 2D US images are acquired on several sagittal image planes and their time-varying 3D positions and orientations are measured using a miniature magnetic 3D position sensor attached to a laparoscopic US (LUS) probe. During the acquisition, the LUS probe is assumed to move together with hepatic surface. Respiratory phases and in-plane 2D deformation fields are estimated from time-varying 2D US images, and then time-varying 3D deformation fields on sagittal image planes are obtained by combining 3D positions and orientations of the image planes. Time-varying 3D deformation field of the volume, that is, 4D deformation field, is obtained by interpolating the 3D deformation fields estimated on several planes. In vivo experiments using a pig liver showed that the proposed method could perform accurate estimation of respiratory cycle and in-plane 2D deformation fields. Furthermore, evaluation for the effects of sagittal plane interval indicated that 4D deformation fields could be stably recovered.     

GPS Laparoscopic Ultrasound: Embedding an Electromagnetic Sensor in a Laparoscopic Ultrasound Transducer

Tracking the location and orientation of a laparoscopic ultrasound (LUS) transducer is a prerequisite in many surgical visualization and navigation applications. Electromagnetic (EM) tracking is a preferred method to track an LUS transducer with an articulating imaging tip. The conventional approach to integrating EM tracking with LUS is to attach an EM sensor on the outer surface of the imaging tip (external setup), which is not ideal for routine clinical use. In this work, we embedded an EM sensor inside a standard LUS transducer. We found that ultrasound image quality and the four-way articulation function of the transducer were not affected by this sensor integration. Furthermore, we found that the tracking accuracy of our integrated transducer was comparable to that of the external setup. An animal study conducted using the developed transducer suggests that an internally embedded EM sensor is a clinically more viable approach, and may be the future of tracking an articulating LUS transducer.     

Ultrasound versus Computed Tomography Assessment of Focal Lung Aeration in Invasively Ventilated ICU Patients

It is unknown whether and to what extent the penetration depth of lung ultrasound (LUS) influences the accuracy of LUS findings. The current study evaluated and compared the LUS aeration score and two frequently used B-line scores with focal lung aeration assessed by chest computed tomography (CT) at different levels of depth in invasively ventilated intensive care unit (ICU) patients. In this prospective observational study, patients with a clinical indication for chest CT underwent a 12-region LUS examination shortly before CT scanning. LUS images were compared with corresponding regions on the chest CT scan at different subpleural depths. For each LUS image, the LUS aeration score was calculated. LUS images with B-lines were scored as the number of separately spaced B-lines (B-line count score) and the percentage of the screen covered by B-lines divided by 10 (B-line percentage score). The fixed-effect correlation coefficient (β) was presented per 100 Hounsfield units. A total of 40 patients were included, and 372 regions were analyzed. The best association between the LUS aeration score and CT was found at a subpleural depth of 5 cm for all LUS patterns (β = 0.30, p < 0.001), 1 cm for A- and B1-patterns (β = 0.10, p < 0.001), 6 cm for B1- and B2-patterns (β = 0.11, p < 0.001) and 4 cm for B2- and C-patterns (β = 0.07, p = 0.001). The B-line percentage score was associated with CT (β = 0.46, p = 0.001), while the B-line count score was not (β = 0.07, p = 0.305). In conclusion, the subpleural penetration depth of ultrasound increased with decreased aeration reflected by the LUS pattern. The LUS aeration score and the B-line percentage score accurately reflect lung aeration in ICU patients, but should be interpreted while accounting for the subpleural penetration depth of ultrasound.     

Laparoscopic ultrasound manipulator with a spring-based elastic mechanism

Purpose

Image guidance is a key technology that can improve the outcome of laparoscopic surgery. However, due to the large deformation caused by digestive organs, a computer-aided navigation system based on preoperative imaging data cannot indicate the correct target position of the lesion (e.g., liver tumors and vessels invisible from the organ surface). To overcome this issue, we developed a laparoscopic ultrasound manipulator with two motorized degrees of freedom at the tip, allowing for the performance of a dexterous ultrasound scan in a confined laparoscopic surgical area.

Method

The developed manipulator consists of a compact and elastic structure using springs, enabling a safe ultrasound scan and avoiding excess force on the inspected organs. The manipulator is a handheld device equipped with four buttons at the handle, which the surgeon directly grasps to send a motion command to the tip structure. The developed prototype realizes two motorized degree-of-freedom motion at the tip. The size of prototype is 15.0 mm in diameter that is usable in conventional laparoscopy. The tip of the manipulator was carefully designed by considering the kinematic model and the results of the finite element analysis.

Results

To assess the prototype, accuracy and rigidity were measured by using a motion processing microscope. The accuracy test showed that the proposed device has a fairly accurate characteristic as a handheld device. This was supposedly caused by the nature of compliant mechanism, which does not have mechanical play in motion. In addition, the intrinsic elastic structure (approximately 2.0 N/mm in most of the range of motion) allowed the ultrasound probe to adequately fit on the curved organ surface without extra effort of manipulation during the inspection. In the in vivo experiment, the yaw motion was found to be effective for investigating the vascular network because the manipulator allows the probe to be rotated while maintaining the same position.

Conclusion

The mechanical evaluation and in vivo test results showed high feasibility of the prototype. We are currently working on further mechanical improvement for commercialization and development of a real-time navigation system that can perform three-dimensional reconstruction of ultrasonographic images by implementing a magnetic position sensor at the tip of the manipulator.

     

Evaluation of a portable image overlay projector for the visualisation of surgical navigation data: phantom studies

Introduction  

Presenting visual feedback for image-guided surgery on a monitor requires the surgeon to perform time-consuming comparisons and diversion of sight and attention away from the patient. Deficiencies in previously developed augmented reality systems for image-guided surgery have, however, prevented the general acceptance of any one technique as a viable alternative to monitor displays. This work presents an evaluation of the feasibility and versatility of a novel augmented reality approach for the visualisation of surgical planning and navigation data. The approach, which utilises a portable image overlay device, was evaluated during integration into existing surgical navigation systems and during application within simulated navigated surgery scenarios.     

腹腔镜超声在中央型肾肿瘤腹腔镜切除术中的应用价值

目的 探讨腹腔镜超声(laparoscopic ultrasonography,LUS)在中央型肾肿瘤腹腔镜切除术中的临床价值。方法 回顾分析行LUS协助肾肿瘤腹腔镜切除术的中央型肾肿瘤18例。LUS重点观察肿瘤的性质与大小、定位及肿瘤的肾表面投影,肿瘤距肾包膜、集合系统及肾门处肾血管的最短距离,肿瘤的血供。结果 18...     

New prototype neuronavigation system based on preoperative imaging and intraoperative freehand ultrasound: system description and validation

Purpose  

The aim of this report is to present IBIS (Interactive Brain Imaging System) NeuroNav, a new prototype neuronavigation system that has been developed in our research laboratory over the past decade that uses tracked intraoperative ultrasound to address surgical navigation issues related to brain shift. The unique feature of the system is its ability, when needed, to improve the initial patient-to-preoperative image alignment based on the intraoperative ultrasound data. Parts of IBIS Neuronav source code are now publicly available on-line.     

Comparing two approaches to rigid registration of three-dimensional ultrasound and magnetic resonance images for neurosurgery

Purpose  

We present a new technique for registering magnetic resonance (MR) and ultrasound images in the context of neurosurgery. It involves generating a pseudo-ultrasound (pseudo-US) from a segmented MR image and uses cross-correlation as the cost function to register the pseudo-US to the real ultrasound data. The algorithm’s performance is compared with that of a state-of-the-art technique that uses a median-filtered MR image to register to a Gaussian-blurred ultrasound using a normalized mutual information (NMI) objective function.     

Lung ultrasonography for assessment of oxygenation response to prone position ventilation in ARDS

Purpose

Prone position (PP) improves oxygenation and outcome of acute respiratory distress syndrome (ARDS) patients with a PaO₂/FiO₂ ratio <150 mmHg. Regional changes in lung aeration can be assessed by lung ultrasound (LUS). Our aim was to predict the magnitude of oxygenation response after PP using bedside LUS.

Methods

We conducted a prospective multicenter study that included adult patients with severe and moderate ARDS. LUS data were collected at four time points: 1 h before (baseline) and 1 h after turning the patient to PP, 1 h before and 1 h after turning the patient back to the supine position. Regional lung aeration changes and ultrasound reaeration scores were assessed at each time. Overdistension was not assessed.

Results

Fifty-one patients were included. Oxygenation response after PP was not correlated with a specific LUS pattern. The patients with focal and non-focal ARDS showed no difference in global reaeration score. With regard to the entire PP session, the patients with non-focal ARDS had an improved aeration gain in the anterior areas. Oxygenation response was not associated with aeration changes. No difference in PaCO₂ change was found according to oxygenation response or lung morphology.

Conclusions

In ARDS patients with a PaO₂/FiO₂ ratio ≤150 mmHg, bedside LUS cannot predict oxygenation response after the first PP session. At the bedside, LUS enables monitoring of aeration changes during PP.