Characterizing close-focus lenses for microendoscopy.

Microendoscopes are commonly used in small lumens in the body, for which a focus near to the distal tip and ability to operate in an aqueous environment are paramount for navigation and disease detection. Commercially available distal optic systems below 1mm in diameter are severely limited, and custom micro lenses are generally very expensive. Gradient index of refraction (GRIN) singlets are available in small diameters but have limited optical performance adjustability. Three-dimensional (3D) printed monolithic optical systems are an emerging option that may be suitable for enabling high performance, close-focus imaging. In this manuscript, we compared the optical performance of three custom distal optic systems; a custom-pitch GRIN singlet, 3D-printed monolithic doublet, and 3D-printed monolithic triplet, with a nominal working distance (WD) of 1.5mm, 0.5mm and 0.4mm in 0.9% saline. These short WDs are ideal for microendoscopy in collapsed or flushed lumens such as pancreatic duct or fallopian tube. The GRIN singlet had performance limited only by the fiber bundle relay over 0.9mm to 1.6 mm depth of field (DOF). The 3D printed doublet was able to achieve a comparable DOF of 0.71mm, while the 3D printed triplet suffered the most limited DOF of 0.55mm. 3D printing enables flexible design of monolithic multi-element systems with aspheric surfaces of very short WDs and relative ease of integration.

Iterative prototyping based on lessons learned from the falloposcope in vivo pilot study experience.

Significance: High grade serous ovarian cancer is the most deadly gynecological cancer, and it is now believed that most cases originate in the fallopian tubes (FTs). Early detection of ovarian cancer could double the 5-year survival rate compared with late-stage diagnosis. Autofluorescence imaging can detect serous-origin precancerous and cancerous lesions in ex vivo FT and ovaries with good sensitivity and specificity. Multispectral fluorescence imaging (MFI) can differentiate healthy, benign, and malignant ovarian and FT tissues. Optical coherence tomography (OCT) reveals subsurface microstructural information and can distinguish normal and cancerous structure in ovaries and FTs. Aim: We developed an FT endoscope, the falloposcope, as a method for detecting ovarian cancer with MFI and OCT. The falloposcope clinical prototype was tested in a pilot study with 12 volunteers to date to evaluate the safety and feasibility of FT imaging prior to standard of care salpingectomy in normal-risk volunteers. In this manuscript, we describe the multiple modifications made to the falloposcope to enhance robustness, usability, and image quality based on lessons learned in the clinical setting. Approach: The ∼0.8 mm diameter falloposcope was introduced via a minimally invasive approach through a commercially available hysteroscope and introducing a catheter. A navigation video, MFI, and OCT of human FTs were obtained. Feedback from stakeholders on image quality and procedural difficulty was obtained. Results: The falloposcope successfully obtained images in vivo. Considerable feedback was obtained, motivating iterative improvements, including accommodating the operating room environment, modifying the hysteroscope accessories, decreasing endoscope fragility and fiber breaks, optimizing software, improving fiber bundle images, decreasing gradient-index lens stray light, optimizing the proximal imaging system, and improving the illumination. Conclusions: The initial clinical prototype falloposcope was able to image the FTs, and iterative prototyping has increased its robustness, functionality, and ease of use for future trials.

Laparoscopic pectopexy for patients with intraabdominal adhesions, lumbar spinal procedures, and other contraindications to sacrocolpopexy: a case series.

Laparoscopic pectopexy is an alternative to sacrocolpopexy utilizing fixation points in the anterior pelvis for vaginal vault suspension; it was originally developed for an obese population. This is a retrospective case series of 7 women who underwent laparoscopic pectopexy at one academic Institution between October 2019 and December 2020. The patients had preoperative vaginal vault prolapse (pelvic organ prolapse quantification system [POP-Q], stage 2 and 3). Pectopexy was performed because of relative contraindications to sacrocolpopexy, including use of antiplatelet therapy, extensive adhesions, and chronic back pain with lumbo-spinal fusion. No intraoperative complications were documented in this cohort. Average blood loss was 32.9 mL. All the patients were discharged home within 24 hours. One patient experienced urinary retention that required release of the retropubic midurethral sling placed at the time of pectopexy. The most recent follow-up examination occurred at an average of 127 days after the procedure. All 7 patients had a resolution of their prolapse (POP-Q ≤1). This case series highlights the application of pectopexy for patients with extensive adhesions, use of antiplatelet therapy and lumbar or sacral spinal surgical history. The complication rates and operative results are comparable with sacrocolpopexy at intermediate-term follow-up in this small case series, indicating that pectopexy may be a promising alternative for patients with relative contraindications to sacrocolpopexy. This is the first report of the application of the technique in North America.