Video recognition of simple mastoidectomy using convolutional neural networks: Detection and segmentation of surgical tools and anatomical regions.

A simple mastoidectomy is used to remove inflammation of the mastoid cavity and to create a route to the skull base and middle ear. However, due to the complexity and difficulty of the simple mastoidectomy, implementing robot vision for assisted surgery is a challenge. To overcome this issue using a convolutional neural network architecture in a surgical environment, each surgical instrument and anatomical region must be distinguishable in real time. To meet this condition, we used the latest instance segmentation architecture, YOLACT. In this study, a data set comprising 5,319 extracted frames from 70 simple mastoidectomy surgery videos were used. Six surgical tools and five anatomic regions were identified for the training. The YOLACT-based model in the surgical environment was trained and evaluated for real-time object detection and semantic segmentation. Detection accuracies of surgical tools and anatomic regions were 91.2% and 56.5% in mean average precision, respectively. Additionally, the dice similarity coefficient metric for segmentation of the five anatomic regions was 48.2%. The mean frames per second of this model was 32.3, which is sufficient for real-time robotic applications.

Radiation Inhibits Lymph Drainage in an Acquired Lymphedema Mouse Hindlimb Model.

Background: Radiation therapy has been applied to prolong the duration of lymphedema. This study aimed to evaluate the effect of radiation on the development of lymphedema in a mouse hindlimb model. Methods and Results: A total of 24 Balb/c mice underwent the right popliteal lymph node excision and the afferent and efferent lymphatics blockage. The radiation group (n = 12) received a single 20 Gy radiation 1 day before surgery in the right hindlimb of each mouse, whereas the control group (n = 12) only received surgery without radiation. The right hindpaw thickness of each mouse was measured twice a week for 4 weeks. Fluorescence microscopy images using fluorescein isothiocyanate-dextran tracer were obtained once weekly. Immunohistochemical (IHC) staining images using anti-lymphatic vessel endothelial hyaluronan receptor-1 (anti-LYVE-1) were obtained at 4 weeks after surgery. The radiation group showed significant increase in the thickness of the right hind paws from 0.5 to 2 weeks compared with the control group. As for fluorescence lymphography, the radiation group showed a lower number of regenerated lymphatics and more congestion of tracers in the operated limb at the surgery sites at 1, 2, 3, and 4 weeks after surgery. For the IHC analysis, the radiation group showed a lower number of regenerated lymphatics per high-power field at the surgery site than the control group. Conclusion: Radiation therapy transiently aggravated the extent of lymphedema by inhibiting regenerated lymphatics in a mouse hindlimb model. However, it did not prolong the duration of lymphedema because the cutaneous interstitial flow contributes to the lymphatic fluid clearance.

Development and Evaluation of a New In Vivo Volume Measuring System in Mouse Tail Lymphedema Model.

Backgrounds: Secondary lymphedema is a common complication of parasitization and breast or gynecologic cancer therapy; however, options for the treatment of lymphedema are ineffective and limited. A mouse tail model is one of the most successful animal models for a lymphatic study. Lymphedema of the mouse tail is characterized by increases in the volume of the extremity caused by accumulation of tissue fluid, proliferation of fibroblasts and adipocytes, and excessive production of collagen. However, the study of lymphedema using mouse has been plagued with difficulty in directly assessing physiologic changes owing to limitations in the measurement of the mouse tail volume. Furthermore, the mouse tail volume cannot be obtained using the general in vivo measurement method such as volumetric water displacement. Methods and Results: Lymphatic researchers have used the truncated cone formula to approximate the volume as used in the numerical approximation of a cylindrical figure. Although this formula is simple and easy to use, it has difficulties of repeatability and accuracy because the measurement procedure is highly subjective and the accuracy depends on the number of divided segments on the tail. In this article, two novel volumetric measurement methods for the mouse tail model were introduced. The methods were evaluated and compared using three mice with surgically created lymphedema on the tails. Conclusions: The two continuous measuring methods showed a possibility to improve the conventional method by continuous measurement using visual and physical detecting methods. The proposed methods facilitate the extraction of longitudinal section-specific information, which can be an important clue in a lymphatic study.

Fluoroscopy-Guided Peroral Placement of a Self-Expandable Metallic Stent for Malignant Jejunal Obstruction in a Non-surgically Altered Stomach.

Malignant small bowel obstruction is a common and distressing complication in advanced cancer patients. Recently, stent placement was reported to be a safe and effective alternative treatment. However, there are only a few case reports associated with stent placement in malignant jejunal obstruction. Furthermore, most patients had a history of gastrectomy before stent placement, which shortens the catheterization pathway. In our case series, we present five cases of malignant proximal jejunal obstruction in a non-surgically altered stomach in the management of fluoroscopy-guided self-expandable metallic stent placement and discuss the interventional management and clinical outcomes. LEVEL OF EVIDENCE: Level 4, Case Series.