Fetoscopic Procedures Research Articles

Enhanced recovery after fetal spina bifida surgery: global practice.

Enhanced recovery after surgery (ERAS) protocols are multimodal evidence-based care plans that have been adopted for multiple surgical procedures to promote faster and better patient recovery and shorter hospitalization. This study aimed to explore whether worldwide fetal therapy centers offering prenatal myelomeningocele repair implement the ERAS principles and to provide recommendations for improved perioperative management of patients. In this survey study, a total of 53 fetal therapy centers offering prenatal surgery for open spina bifida were identified and invited to complete a digital questionnaire covering their pre-, intra- and postoperative management. An overall score was calculated per center based on compliance with 20 key ERAS principles, extrapolated from ERAS guidelines for Cesarean section, gynecological oncology and colorectal surgery. Each item was awarded a score of 1 or 0, depending, respectively, on whether the center did or did not comply with that principle, with a maximum score of 20. The questionnaire was completed by 46 centers in 17 countries (response rate, 87%). In total, 22 (48%) centers performed exclusively open fetal surgery (laparotomy and hysterotomy), whereas 14 (30%) offered both open and fetoscopic procedures and 10 (22%) used only fetoscopy. The perioperative management of patients undergoing fetoscopic and open surgery was very similar. The median ERAS score was 12 (range, 8-17), with a mean ± SD of 12.5 ± 2.4. Center compliance was the highest for the use of regional anesthesia (98%), avoidance of bowel preparation (96%) and thromboprophylaxis (96%), while the lowest compliance was observed for preoperative carbohydrate loading (15%), a 2-h fasting period for clear fluids (20%), postoperative nausea and vomiting prevention (33%) and early feeding (35%). ERAS scores were similar in centers with a short (2-5 days), medium (6-10 days) and long (≥ 11 days) hospital stay (mean ± SD, 12.9 ± 2.4, 12.1 ± 2.0 and 10.3 ± 3.2, respectively, P = 0.15). Furthermore, there was no significant association between ERAS score and surgical technique or case volume. The perioperative management of fetal spina bifida surgery is highly variable across fetal therapy centers worldwide. Standardized protocols integrating ERAS principles may improve patient recovery, reduce maternal morbidity and shorten the hospital stay after fetal spina bifida surgery. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Real-time placental vessel segmentation in fetoscopic laser surgery for Twin-to-Twin Transfusion Syndrome

Twin-to-Twin Transfusion Syndrome (TTTS) is a rare condition that affects about 15% of monochorionic pregnancies, in which identical twins share a single placenta. Fetoscopic laser photocoagulation (FLP) is the standard treatment for TTTS, which significantly improves the survival of fetuses. The aim of FLP is to identify abnormal connections between blood vessels and to laser ablate them in order to equalize blood supply to both fetuses. However, performing fetoscopic surgery is challenging due to limited visibility, a narrow field of view, and significant variability among patients and domains. In order to enhance the visualization of placental vessels during surgery, we propose TTTSNet, a network architecture designed for real-time and accurate placental vessel segmentation. Our network architecture incorporates a novel channel attention module and multi-scale feature fusion module to precisely segment tiny placental vessels. To address the challenges posed by FLP-specific fiberscope and amniotic sac-based artifacts, we employed novel data augmentation techniques. These techniques simulate various artifacts, including laser pointer, amniotic sac particles, and structural and optical fiber artifacts. By incorporating these simulated artifacts during training, our network architecture demonstrated robust generalizability. We trained TTTSNet on a publicly available dataset of 2060 video frames from 18 independent fetoscopic procedures and evaluated it on a multi-center external dataset of 24 in-vivo procedures with a total of 2348 video frames. Our method achieved significant performance improvements compared to state-of-the-art methods, with a mean Intersection over Union of 78.26% for all placental vessels and 73.35% for a subset of tiny placental vessels. Moreover, our method achieved 172 and 152 frames per second on an A100 GPU, and Clara AGX, respectively. This potentially opens the door to real-time application during surgical procedures. The code is publicly available at https://github.com/SanoScience/TTTSNet.

Placental vessel segmentation and registration in fetoscopy: Literature review and MICCAI FetReg2021 challenge findings

Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfusion Syndrome (TTTS). The procedure involves photocoagulation pathological anastomoses to restore a physiological blood exchange among twins. The procedure is particularly challenging, from the surgeon’s side, due to the limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to amniotic fluid turbidity, and variability in illumination. These challenges may lead to increased surgery time and incomplete ablation of pathological anastomoses, resulting in persistent TTTS. Computer-assisted intervention (CAI) can provide TTTS surgeons with decision support and context awareness by identifying key structures in the scene and expanding the fetoscopic field of view through video mosaicking. Research in this domain has been hampered by the lack of high-quality data to design, develop and test CAI algorithms. Through the Fetoscopic Placental Vessel Segmentation and Registration (FetReg2021) challenge, which was organized as part of the MICCAI2021 Endoscopic Vision (EndoVis) challenge, we released the first large-scale multi-center TTTS dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms with a focus on creating drift-free mosaics from long duration fetoscopy videos. For this challenge, we released a dataset of 2060 images, pixel-annotated for vessels, tool, fetus and background classes, from 18 in-vivo TTTS fetoscopy procedures and 18 short video clips of an average length of 411 frames for developing placental scene segmentation and frame registration for mosaicking techniques. Seven teams participated in this challenge and their model performance was assessed on an unseen test dataset of 658 pixel-annotated images from 6 fetoscopic procedures and 6 short clips. For the segmentation task, overall baseline performed was the top performing (aggregated mIoU of 0.6763) and was the best on the vessel class (mIoU of 0.5817) while team RREB was the best on the tool (mIoU of 0.6335) and fetus (mIoU of 0.5178) classes. For the registration task, overall the baseline performed better than team SANO with an overall mean 5-frame SSIM of 0.9348. Qualitatively, it was observed that team SANO performed better in planar scenarios, while baseline was better in non-planner scenarios. The detailed analysis showed that no single team outperformed on all 6 test fetoscopic videos. The challenge provided an opportunity to create generalized solutions for fetoscopic scene understanding and mosaicking. In this paper, we present the findings of the FetReg2021 challenge, alongside reporting a detailed literature review for CAI in TTTS fetoscopy. Through this challenge, its analysis and the release of multi-center fetoscopic data, we provide a benchmark for future research in this field.

Minimally Invasive Bimanual Fetal Surgery-A Review.

Background: The aim of this review is to discuss experimental and clinical techniques and interventions of fetal surgery which have been performed minimally invasively by the means of a three-port approach for the fetoscope and instruments for the left and right hand of the surgeon (bimanual minimally invasive fetal surgery). Methods: a print and electronic literature search was performed; the titles and abstracts were screened and included reports were reviewed in a two-step approach. First, reports other than minimally invasive fetal surgery were excluded, then a full text review and analysis of the reported data was performed. Results: 17 reports were included. The heterogeneity of the included reports was high. Although reports on human fetoscopic surgical procedures can be found, most of them do not pick out bimanual fetal surgery as a central theme but rather address interventions applying a fetoscope with a working channel for a laser fiber, needle or flexible instrument. Most reports were on experimentation in animal models, the human application of minimally invasive fetoscopic bimanual surgery is rare and has at best been explored for the prenatal treatment of spina bifida. Some reported bimanual fetoscopic procedures were performed on the exteriorized uterus via a maternal laparotomy and can therefore not be classified as being truly minimally invasive. Discussion: our results demonstrate that minimally invasive fetoscopic bimanual surgery is rare, even in animal models, excluding many other techniques and procedures that are loosely termed ‘minimally invasive fetal surgery’ which we suggest to better label as ‘interventions’. Thus, more research on percutaneous minimally invasive bimanual fetoscopic surgery is warranted, with the aim to reduce the maternal, uterine and fetal trauma for correction of congenital malformations.

Fetal intervention: Less developed field of interventional radiology

Interventional radiology (IR) has played an essential role in diagnosing and treating various intra natal entities with minimally invasive surgical procedures. IR treatment is the substitute to the many procedures in which once open surgery was needed. IR procedure can be performed under Digital Radiography (x-ray), Ultrasound, Magnetic Resonance Imaging (MRI) or Computed Tomography (CT). IR has proved to increase effectiveness as medical imaging technology gives radiologists high visibility, reduces risk as surgery performed are minimally invasive, saves time as there is a short hospital stay, and reduces the pain as procedures are performed with a small incision. Because of quicker recovery time, patients can get back to their daily routine early. Progressive development of prenatal intervention and surgeries was possible due to rapid advances in imaging techniques and prenatal diagnosis over the last few decades. Rapid advanced techniques have become an integral part of managing high-risk pregnancies. In addition to this, the rapidly growing capability of digital optics and miniaturized instrumentation has now allowed fetoscopic procedures to become a reality. With improved imaging techniques, the identification of congenital defects and fetal malformations increases during the antenatal period. Understanding how to treat specific fetal conditions improves outcomes from these treatment modalities. We provide an assessment that begins with a crisp background of fetal surgery, including the history, ethics surrounding fetal surgery, and considerations of dealing with the problems during the fetal intervention.

Perinatal outcomes of iatrogenic chorioamniotic separation following fetoscopic surgery: systematic review and meta-analysis.

To compare the perinatal outcomes between pregnancies with and those without iatrogenic chorioamniotic separation (iCAS) following fetoscopic intervention. We performed a search in PubMed, EMBASE, Scopus, Web of Science and Google Scholar from inception up to December 2020 for studies comparing perinatal outcomes between pregnancies that developed and those that did not develop iCAS after fetoscopic intervention for twin-to-twin transfusion syndrome (TTTS), open neural tube defect (ONTD) or congenital diaphragmatic hernia. A random-effects model was used to pool the mean differences (MD) or odds ratios (OR) and the corresponding 95% CI. The primary outcome was neonatal survival. Secondary outcomes included gestational age (GA) at intervention and at delivery, interval from intervention to delivery and incidence of preterm prelabor rupture of membranes (PPROM) and preterm delivery. The methodological quality of the included studies was evaluated using the Newcastle-Ottawa scale. The search identified 348 records, of which seven studies (six on fetoscopic laser photocoagulation (FLP) for TTTS and one on fetoscopic repair for ONTD) assessed the perinatal outcomes of pregnancies that developed iCAS after fetoscopic intervention. Given that only one study reported on fetoscopic ONTD repair, the meta-analysis was limited to TTTS pregnancies and included six studies (total of 1881 pregnancies). Pregnancies that developed iCAS after FLP for TTTS, compared with those that did not, had significantly lower GA at the time of intervention (weeks) (MD, -1.07 (95% CI, -1.89 to -0.24); P = 0.01) and at delivery (weeks) (MD, -1.74 (95% CI, -3.13 to -0.34); P = 0.01) and significantly lower neonatal survival (OR, 0.41 (95% CI, 0.24-0.70); P = 0.001). In addition, development of iCAS after FLP for TTTS increased significantly the risk for PPROM < 34 weeks' gestation (OR, 3.98 (95% CI, 1.76-9.03); P < 0.001) and preterm delivery < 32 weeks (OR, 1.80 (95% CI, 1.16-2.80); P = 0.008). iCAS is a common complication after FLP for TTTS. In patients undergoing FLP for TTTS, iCAS develops more often with earlier GA at intervention and is associated with earlier GA at delivery, higher risk of PPROM < 34 weeks' gestation and preterm delivery < 32 weeks and lower neonatal survival. Given the limitations of this meta-analysis and lack of literature reporting on other types of fetoscopic intervention, the presented findings should be interpreted with caution and should not be generalized to fetoscopic procedures used to treat other fetal conditions. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Ultrasound findings in Pseudoamniotic band syndrome after fetoscopic surgery: Antenatal description of three cases and review of literature

IntroductionPseudoamniotic Bands Syndrome (PABS) was described as iatrogenic complication from in utero procedure as fetoscopy. ObjectiveThe aim of our study was to identify the ultrasound findings in PABS diagnosed prenatally MethodsFirst, we reported cases of PABS following fetoscopic surgery that were diagnosed prenatally in our institution. We collected all ultrasound data with fetal and neonatal issues. Then, a literature review was conducted by searching the Medline and Cochrane Library computer databases until 2020 to find publications that involve PABS diagnosed prenatally or postnatally. The following keywords were selected and combined: “pseudoamniotic bands syndrome”, “fetoscopy”, “fetal surgery”. ResultsWe collected three cases of PABS diagnosed prenatally in our center following fetoscopic procedures for complicated monochorionic pregnancies. Among these cases, we reported the following ultrasound findings: floating membrane, amniotic bands, striction of limbs, perilesional edema, reduced member size and anomalies of Doppler flow. Including our cases, we reported 23 published PABS of which eight (35%) were prenatally diagnosed. When it was diagnosed, mean GA at PABS diagnosis was 23 weeks (mean interval from fetoscopic to diagnosis was 4 weeks). Three fetoscopic release of amniotic bands were described. The principal parts affected were the limbs, more particularly the extremities. ConclusionPABS was accessible to an antenatal diagnosis, as well as ABS. Although it is a rare complication of fetoscopic surgery, ultrasound examinations after procedure should focus on PABS signs to improve prognosis of the neonates.

Perioperative Care of Patients Diagnosed With Twin-to-Twin Transfusion Syndrome Undergoing Laparoscopic-Assisted Fetoscopic Placental Laser Photocoagulation.

Twin-to-twin transfusion syndrome (TTTS) is a condition that results in unbalanced blood flow between two fetuses. Patients diagnosed with TTTS can experience maternal or fetal morbidity and mortality. Depending on the severity of TTTS, laser ablation of placental anastomoses may be the most effective treatment. The preferred treatment method requires percutaneous entry to the uterus; however, some patient circumstances (eg, placenta location) require a laparoscopic-assisted procedure. During the preoperative appointments, clinicians assess the condition of the fetuses and patients may participate in genetic counseling. Intraoperative care involves an interdisciplinary team that may include a pediatric general surgeon, maternal-fetal medicine specialists, an RN circulator, a scrub person, and an anesthesia professional. Perioperative nurses should have knowledge of the pathophysiology of TTTS, including its natural progression. They also should understand preoperative and intraoperative patient care requirements to provide safe and effective care for patients undergoing laparoscopic-assisted fetoscopic placental laser photocoagulation procedures.

Comparison of two- and three-dimensional endoscopic visualization for fetal myelomeningocele repair: a pilot study using a fetoscopic surgical simulator.

The objective of this study was to evaluate the utility of three-dimensional (3D) versus conventional two-dimensional (2D) endoscopy for fetal myelomeningocele repair using a low-fidelity fetoscopic surgical simulator. A low-fidelity fetoscopic box trainer was developed for surgical simulation of myelomeningocele repair. Participants with varying surgical experience were recruited and completed three essential tasks (cutting skin, dural patch placement, and suturing skin) using both 2D and 3D endoscopic visualization. Participants were randomized to begin all tasks in either 2D or 3D. Time to completion was measured for each task, and each participant subsequently completed the NASA Load Index test and a questionnaire evaluating their experience. Sixteen participants completed the study tasks using both 2D and 3D endoscopes in the simulator. While the mean performance time across all tasks was shorter with 3D versus 2D endoscopy (cutting skin, 47 vs. 54 seconds; dural patch placement, 38 vs. 52 seconds; and suturing skin, 424 vs. 499 seconds), the results did not reach statistical significance. When comparing times to completion of each of the three tasks between levels of expertise, participants in the expert category were faster when suturing skin on the 2D modality (P = 0.047). Under 3D visualization, experts were faster at cutting the skin (P = 0.008). When comparing experiences using the NASA-TLX test, participants felt that their performance was better using 3D over the 2D system (P = 0.045). Overall, 13 of 16 (81.3%) participants preferred 3D over 2D visualization. Three-dimensional endoscopes could potentially be used in the near future for relative improvement in visualization and possibly performance during complex fetoscopic procedures such as prenatal repair of myelomeningocele defects. Further studies utilizing 3D scopes for other related procedures may potentially support clinical implementation of this technology in fetal surgery and also prove to be a useful tool in surgical training.

Foetal therapies and their influence on preterm birth.

Foetal therapy aims to improve perinatal survival or to prevent severe long-term handicap. Foetal medicine opens a new territory by treating the foetus as a patient. The mother has nothing to gain in terms of health benefits, yet she is inherently also undergoing treatment. In utero foetal interventions can be divided into ultrasound-guided minimally invasive procedures, fetoscopic procedures and open hysterotomy procedures, which carry an inherent risk of ruptured membranes and preterm birth. In this review, we summarise the conditions that may benefit from foetal therapy and review the current therapies on offer, each with their associated risk of ruptured membrane and preterm birth. We also look into some risk limiting and preventative strategies to mitigate these complications.

Fetal anesthesia: intrauterine therapies and immediate postnatal anesthesia for noncardiac surgical interventions.

This review describes maternal and fetal anesthetic management for noncardiac fetal surgical procedures, including the management of lower urinary tract obstruction, congenital diaphragmatic hernia (CDH), myelomeningocele, sacrococcygeal teratoma, prenatally anticipated difficult airway and congenital lung lesions. Fetal interventions range from minimally invasive fetoscopic procedures to mid-gestation open surgery, to ex-utero intrapartum treatment procedure. Anesthetic management depends on the fetal intervention and patient characteristics. Anesthesia for most minimally invasive procedures can consist of intravenous sedation and local anesthetic infiltration in clinically appropriate maternal patients. Open fetal and ex-utero intrapartum treatment procedures require maternal general anesthesia with volatile anesthetic and other medications to maintain uterine relaxation. Tracheal balloons are a promising therapy for CDH and can be inserted via minimally invasive techniques. Management of the prenatally anticipated difficult airway during delivery and removal of tracheal balloons from patients with CDH during delivery can be clinically dynamic and require flexibility, seamless communication and a high-functioning, multidisciplinary care team. Maternal and fetal anesthetic management is tailored to the fetal intervention and the underlying health of the fetus and mother.

FetNet: a recurrent convolutional network for occlusion identification in fetoscopic videos

PurposeFetoscopic laser photocoagulation is a minimally invasive surgery for the treatment of twin-to-twin transfusion syndrome (TTTS). By using a lens/fibre-optic scope, inserted into the amniotic cavity, the abnormal placental vascular anastomoses are identified and ablated to regulate blood flow to both fetuses. Limited field-of-view, occlusions due to fetus presence and low visibility make it difficult to identify all vascular anastomoses. Automatic computer-assisted techniques may provide better understanding of the anatomical structure during surgery for risk-free laser photocoagulation and may facilitate in improving mosaics from fetoscopic videos.MethodsWe propose FetNet, a combined convolutional neural network (CNN) and long short-term memory (LSTM) recurrent neural network architecture for the spatio-temporal identification of fetoscopic events. We adapt an existing CNN architecture for spatial feature extraction and integrated it with the LSTM network for end-to-end spatio-temporal inference. We introduce differential learning rates during the model training to effectively utilising the pre-trained CNN weights. This may support computer-assisted interventions (CAI) during fetoscopic laser photocoagulation.ResultsWe perform quantitative evaluation of our method using 7 in vivo fetoscopic videos captured from different human TTTS cases. The total duration of these videos was 5551 s (138,780 frames). To test the robustness of the proposed approach, we perform 7-fold cross-validation where each video is treated as a hold-out or test set and training is performed using the remaining videos.ConclusionFetNet achieved superior performance compared to the existing CNN-based methods and provided improved inference because of the spatio-temporal information modelling. Online testing of FetNet, using a Tesla V100-DGXS-32GB GPU, achieved a frame rate of 114 fps. These results show that our method could potentially provide a real-time solution for CAI and automating occlusion and photocoagulation identification during fetoscopic procedures.

Fetoscopic techniques for prenatal covering of gastroschisis in an ovine model are technically demanding and do not lead to permanent anchoring on the fetus until the end of gestation.

This is the cumulative technical report on the operative procedures and limitations of fetoscopic bag insertion, intestinal bag placement, and bag fixation to the fetus in a series of pilot studies in an ovine model for prenatal treatment of gastroschisis. In 24 German blackhead sheep, a surgically created gastroschisis was managed by fetoscopic placement of the extruded intestines into a bag. The bag was then fastened onto the fetal abdominal wall. Different materials (sterile gloves, latex condoms, laparosopic retrieval bags) and different fixation techniques (laparoscopic staplers, interrupted and continuous sutures) have been examined. The fetuses were retrieved and evaluated at the end of gestation. Uterine bag insertion was successful in 15 of 24 (62.5%) and intestinal bag placement in 10 of 15 available fetuses (66.6%). The main factor limiting fetoscopic procedures was chorioamniotic separation (CAS). Sterilized condoms provided the most appropriate type of bags and the V-Loc™ running suture, the most expedient type of fixation, which was achieved in 9 of the 10 fetuses (complete = 2, partially = 7) by using a three port access (5mm and 2 × 3mm). All bags were encountered completely or partially dislocated from the fetus at the end of gestation. Fetoscopic intestinal bag placement and fixation in gastroschisis technically demanding. None of the evaluated techniques led to permanent anchorage of the bag to the fetus. The development of specially designed instruments, bags and fixation methods is required to optimize this approach.

Influence of osmolarity and hydration on the tear resistance of the human amniotic membrane

The amnion is considered to be the load-bearing part of the fetal membranes. We investigated the influence of osmolarity of the testing medium and hydration on its fracture toughness. Mode I fracture tests revealed that physiological variations in the bath osmolarity do not influence the tear resistance of amnion, while larger changes, i.e. from physiological saline solution to distilled water, lead to a significant reduction of the fracture toughness. Uniaxial tensile tests on collagen hydrogels confirmed the reduction in toughness, suggesting that lower bath osmolarity triggers changes in the failure properties of single collagen fibers. Prenatal surgeries, in particular fetoscopic procedures with partial amniotic carbon dioxide insufflation, might result in dehydration of the amnion. Dehydration induced a brittle behavior; however, subsequent rehydration for 15 min resulted in a similar tear resistance as for the fresh tissue.

Partial amniotic carbon dioxide insufflation for fetal surgery.

Partial amniotic carbon dioxide insufflation (PACI) involves insufflating the amniotic sac with carbon dioxide (CO2 ) and, in some cases, draining some of the amniotic fluid. The creation of a gaseous intra-amniotic compartment improves visualization, even in the presence of limited bleeding, and creates the work space required for complex fetoscopic procedures. Clinically, PACI is mostly used to perform fetoscopic myelomeningocele (MMC) repair, enabling a minimally invasive alternative to open fetal surgery. However, evidence of the fetal safety of PACI is limited. Previous animal experiments in sheep demonstrate that PACI induces fetal hypercapnia and acidosis with largely unknown short and longer term implications. In this review, we examine the literature for the physiological effects of intrauterine insufflation pressure, duration, humidity, and the role of maternal hyperventilation on fetal physiology and well-being.

Combined video-endoscopic and transcutaneous approach for surgical treatment of acute necrotizing pancreatitis

Now-a-days, high-resolution ultrasound allows an accurate and relatively early diagnosis of congenital malformations. In a limited number of such conditions foetal surgery may be lifesaving. However, premature labour has been the major drawback for open foetal surgery. Recently, improvement of video-endoscopic technology has boosted the development of operative techniques for feto-endoscopic surgery, which has been demonstrated to be less invasive than the open approach. Main clinical application of fetoscopic procedures today is the treatment of feto-foetal transfusion syndrome.Although still in development, feto-endoscopic surgery seems to offer new hope for surgical foetal therapy not only in cases of life threatening conditions. Experimental intrauterine correction of cleft lip and palate (CLP) has been lately performed using the feto-endoscopic approach. This procedure offers two major advantages: first, scarless foetal wound healing and bone healing without callus formation, which would also allow a better/normal maxillary growth, and second, significant decrease of foetal and maternal morbidity.Herein, we report the current status of experimental and clinical foetal surgery and propose possible directions for continuing research to make intrauterine procedures safer. Furthermore, we discuss current knowledge and new perspectives of experimental foetal cleft lip and palate repair, which in the future may lead to such excellent results in the operative treatment of clefts, that less or no secondary corrections and therapies, such as orthodontic, dental, logopedic, etc. would be needed. Only if these conditions can be fulfilled, will we be able to improve substantially our therapy for the human foetus with a cleft lip and palate. In spite of all efforts, however, it must be considered that it may not ever be possible to find the optimal treatment method for this or other craniofacial malformations.

A Continuum Robot and Control Interface for Surgical Assist in Fetoscopic Interventions.

Twin–twin transfusion syndrome requires interventional treatment using a fetoscopically introduced laser to sever the shared blood supply between the fetuses. This is a delicate procedure relying on small instrumentation with limited articulation to guide the laser tip and a narrow field of view to visualize all relevant vascular connections. In this letter, we report on a mechatronic design for a comanipulated instrument that combines concentric tube actuation to a larger manipulator constrained by a remote centre of motion. A stereoscopic camera is mounted at the distal tip and used for imaging. Our mechanism provides enhanced dexterity and stability of the imaging device. We demonstrate that the imaging system can be used for computing geometry and enhancing the view at the operating site. Results using electromagnetic sensors for verification and comparison to visual odometry from the distal sensor show that our system is promising and can be developed further for multiple clinical needs in fetoscopic procedures.

Pediatric medical device development by surgeons via capstone engineering design programs

BackgroundThere is a need for pediatric medical devices that accommodate the unique physiology and anatomy of pediatric patients that is increasingly receiving more attention. However, there is limited literature on the programs within children's hospitals and academia that can support pediatric device development. We describe our experience with pediatric device design utilizing collaborations between a children's hospital and two engineering schools. MethodsUtilizing the academic year as a timeline, unmet pediatric device needs were identified by surgical faculty and matched with an engineering mentor and a team of students within the Capstone Engineering Design programs at two universities. The final prototypes were showcased at the end of the academic year and if appropriate, provisional patent applications were filed. ResultsAll twelve teams successfully developed device prototypes, and five teams obtained provisional patents. The prototypes that obtained provisional patents included a non-operative ureteral stent removal system, an evacuation device for small kidney stone fragments, a mechanical leech, an anchoring system of the chorio-amniotic membranes during fetal surgery, and a fetal oxygenation monitor during fetoscopic procedures. ConclusionsCapstone Engineering Design programs in partnership with surgical faculty at children's hospitals can play an effective role in the prototype development of novel pediatric medical devices. Levels of evidenceN/A – No clinical subjects or human testing was performed.

Self-contained image mapping of placental vasculature in 3D ultrasound-guided fetoscopy.

Surgical navigation technology directed at fetoscopic procedures is relatively underdeveloped compared with other forms of endoscopy. The narrow fetoscopic field of views and the vast vascular network on the placenta make examination and photocoagulation treatment of twin-to-twin transfusion syndrome challenging. Though ultrasonography is used for intraoperative guidance, its navigational ability is not fully exploited. This work aims to integrate 3D ultrasound imaging and endoscopic vision seamlessly for placental vasculature mapping through a self-contained framework without external navigational devices. This is achieved through development, integration, and experimentation of novel navigational modules. Firstly, a framework design that addresses the current limitations based on identified gaps is conceptualized. Secondly, integration of navigational modules including (1) ultrasound-based localization, (2) image alignment, and (3) vision-based tracking to update the scene texture map is implemented. This updated texture map is projected to an ultrasound-constructed 3D model for photorealistic texturing of the 3D scene creating a panoramic view of the moving fetoscope. In addition, a collaborative scheme for the integration of the modular workflow system is proposed to schedule updates in a systematic fashion. Finally, experiments are carried out to evaluate each modular variation and an integrated collaborative scheme of the framework. The modules and the collaborative scheme are evaluated through a series of phantom experiments with controlled trajectories for repeatability. The collaborative framework demonstrated the best accuracy (5.2% RMS error) compared with all the three single-module variations during the experiment. Validation on an ex vivo monkey placenta shows visual continuity of the freehand fetoscopic panorama. The proposed developed collaborative framework and the evaluation study of the framework variations provide analytical insights for effective integration of ultrasonography and endoscopy. This contributes to the development of navigation techniques in fetoscopic procedures and can potentially be extended to other applications in intraoperative imaging.

Training Significantly Improves Fetoscopy Performance: A Pilot Randomized Controlled Trial.

Background Implementation of complex fetoscopic procedures that included intracorporeal suturing has been limited due to technical difficulties that might be surmounted with adequate training. Evaluating the impact of laparoscopic or fetoscopic training on fetoscopic performance was the aim of this study. Methods To evaluate fetoscopic performance after either laparoscopic or fetoscopic training, subjects were asked to perform four surgeon's square knots fetoscopically prior and post 2 hours of hands-on training. All subjects were medical students and novice in laparoscopic and fetoscopic interventions. Total time, knot stability (evaluated via tensiometer), suture accuracy, knot quality, and fetoscopic performance were assessed. Results Forty-six subjects were included in the study; after simple randomization, 24 were trained fetoscopically and 22 laparoscopically. Both groups had comparable baseline characteristics and improved after training significantly regarding all aspects assessed in this study. Subjects who trained fetoscopically were superior in terms of suturing and knot-tying performance. Conclusion Training significantly improves fetoscopic performance and may indeed be the keystone for future complex fetoscopic interventions. It seems advisable to train rather fetoscopically than laparoscopically resulting in higher suture and knot-tying quality.