The art of fetoscopy: a step toward minimally invasive fetal therapy

Fetoscopic versus Ultrasound-Guided Intravascular Delivery of Maternal Bone Marrow Cells in Fetal Macaques: A Technical Model for Intrauterine Haemopoietic Cell Transplantation

INTRODUCTION

Significant limitations with existing treatments for major haemoglobinopathies motivate the development of effective intrauterine therapy. We assessed the feasibility of fetoscopic and ultrasound-guided intrauterine haemopoietic cell transplantation (IUHCT) in macaque fetuses in early gestation when haemopoietic and immunological ontogeny is anticipated to enable long-term donor cell engraftment.

MATERIAL AND METHODS

Fluorescent-labelled bone marrow-derived mononuclear cells from 10 pregnant Macaca fascicularis were injected into their fetuses at E71-114 (18.9-170.0E+6 cells/fetus) by fetoscopic intravenous (n = 7) or ultrasound (US)-guided intracardiac injections, with sacrifice at 24 h to examine donor-cell distribution.

RESULTS

Operating times ranged from 35 to 118 min. Chorionic membrane tenting and intrachorionic haemorrhage were observed only with fetoscopy (n = 2). Labelled cells were stereoscopically visualised in lung, spleen, liver, and placenta. Donor-cell chimerism was highest in liver, spleen, and heart by flow cytometry, placenta by unique polymorphism qPCR, and was undetected in blood. Chimerism was 2-3 log-fold lower in individual organs by qPCR than by flow cytometry.

DISCUSSION

Both fetoscopic and US-guided IUHCT were technically feasible, but fetoscopy caused more intraoperative complications in our pilot series. The discrepancy in chimerism detection predicts the challenges in long-term surveillance of donor-cell chimerism. Further studies of long-term outcomes in the non-human primate are valuable for the development of clinical protocols for IUHCT.

A Multimodality Navigation System for Endoscopic Fetal Surgery: A Phantom Case Study for Congenital Diaphragmatic Hernia

This article presents a multi-modality tracking and navigation system achieved by merging optical tracking and ultrasound imaging into a novel navigation software to help in surgical pre-planning and real-time target setting and guidance. Fetal surgeries require extensive experience in coordination of hand-eye-ultrasound-surgical equipment, knowledge, and precise assessment of relative anatomy. While there are navigation systems available for similar constrained working spaces in arthroscopic and cardiovascular procedures, fetal minimally invasive surgery does not yet have a dedicated navigation platform capable of supporting robotic instruments that can be adapted to the set of unique procedures. This article discusses the testing of the novel multi-modality navigation system in a phantom environment developed for this purpose. The outcomes suggest that the subjects demonstrated an increase in average reaching accuracy by about 60% and an overall reduction in time taken by 33.6%. They also showed higher levels of confidence in reaching the targets, which was visualised from the pattern of trajectory of movements during the procedure. To evaluate the navigation system, a phantom surgical environment was found necessary. Therefore, the article also discusses the details of the development of a fetal phantom environment for congenital diaphragmatic hernia for surgical testing, evaluation, and training. A surgical procedure was conducted on the phantom using the proposed tracking navigation system and using only ultrasound.