Computer-based endoscopic image-processing technology for endourology and laparoscopic surgery

A half jaw panoramic stitching method of intraoral endoscopy images based on dental arch arrangement

To address the challenges of repetitive and low-texture features in intraoral endoscopic images, a novel methodology for stitching panoramic half jaw images of the oral cavity is proposed. Initially, an enhanced self-attention mechanism guided by Time-Weighting concepts is employed to augment the clustering potential of feature points, thereby increasing the number of matched features. Subsequently, a combination of the Sinkhorn algorithm and Random Sample Consensus (RANSAC) is utilized to maximize the count of matched feature pairs, accurately remove outliers and minimize error. Last, to address the unique spatial alignment among intraoral endoscopic images, a wavelet transform and weighted fusion algorithm based on dental arch arrangement in intraoral endoscopic images have been developed, specifically for use in the fusion stage of intraoral endoscopic images. This enables the local oral images to be precisely positioned along the dental arch, and seamless stitching is achieved through wavelet transformation and a gradual weighted fusion technique. Experimental results demonstrate that this method yields promising outcomes in panoramic stitching tasks for intraoral endoscopic images, achieving a matching accuracy of 84.6% and a recall rate of 78.4% in a dataset with an average overlap of 35%. A novel solution for panoramic stitching of intraoral endoscopic images is provided by this method.

Comparison of laparoscopic versus open simple nephrectomy in patients with xanthogranulomatous pyelonephritis: A singlecenter analysis of outcomes and predictors of surgical approaches and complications

Background

The aim of this study was to compare the outcomes of open simple nephrectomy and laparoscopic simple nephrectomy in patients with xanthogranulomatous pyelonephritis (XGP) in a single-institutional retrospective study and to identify predictive factors of surgical approaches and complications.

Materials and methods

We retrospectively analyzed the data of 67 consecutive patients with a histopathological diagnosis of XGP who underwent either open simple nephrectomy (ON) or laparoscopic simple nephrectomy (LN) from January 2014 to April 2020. The primary endpoint was the evaluation of perioperative outcomes and complications. Secondary endpoints were to define factors influencing the surgical approach and the likelihood of postoperative complications.

Results

Overall, 44 out of 67 patients (65.67%) underwent ON, while 23 (34.33%) underwent LN. Patients in the ON group experienced more postoperative pain according to the visual analogic scale (p = 0.032). Moreover, time to deambulation and time to return to full daily activities, assessed according to the 12-Item Short Form Survey physical and mental component summary scores questionnaires, were significantly shorter in the LN group (p = 0.021, p < 0.001, and p < 0.001, respectively). Of note, there were no significant differences in intraoperative and postoperative complication rates among the groups (p = 0.258 and p = 0.317, respectively). No conversion to open surgery was described. Logistic regression analysis demonstrated that urgency (p = 0.025) was the only predictor associated with a higher risk of intraoperative complications. However, no independent factors associated with postoperative complications or with the surgical approach of choice were found.

Conclusions

Based on our results, laparoscopic treatment of XGP represents a feasible alternative to ON, resulting in less postoperative pain and faster recovery. In skilled hands, LN should be considered as the treatment of choice for XGP.

Personalised three-dimensional printed transparent kidney model for robot-assisted partial nephrectomy in patients with complex renal tumours (R.E.N.A.L. nephrometry score ≥7): a prospective case-matched study

OBJECTIVES

To evaluate the effectiveness of a three-dimensional (3D) printed transparent kidney model as a surgical navigator for robot-assisted partial nephrectomy (RPN) in patients with complex renal tumours, defined by a R.E.N.A.L. (Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location) nephrometry score of ≥7.

PATIENTS AND METHODS

A total of 80 patients who underwent RPN were included in the present prospective case-matched study (case group [n = 40, application of 3D-printed transparent kidney model during RPN] vs matching group [n = 40, routine protocol]). The RPNs were performed by a single experienced surgeon. The RPN procedure consisted of six steps: (i) preparation of the renal hilar vessel for clamping, (ii) tumour detection and dissection, (iii) robotic ultrasonography, (iv) tumour resection, (v) calyx repair and haemostasis, and (vi) renorrhaphy. The time for each step, console time, and warm ischaemia time were compared between the two groups as a surrogate marker for surgical effectiveness.

RESULTS

Both groups were well-balanced for all baseline characteristics. The use of the model reduced the console time by ~20% compared to the matched group (64.6 vs 78.5 min, P = 0.001). On multivariate logistic regression analysis, tumour radius (P < 0.001) and application of the model (P = 0.009) were identified as significant predictors of a console time of ≤70 min.

CONCLUSION

We established the usefulness of a personalised 3D-printed transparent kidney model for more effective RPNs. Use of the 3D-printed transparent kidney model reduced the operative time even for complex renal tumours and would be expected to broaden the indications for PN.

Small-Incision Laparoscopy-Assisted Surgery Under Abdominal Cavity Irrigation in a Porcine Model

Background: Laparoscopic and robot-assisted surgeries are performed under carbon dioxide insufflation. Switching from gas to an isotonic irrigant introduces several benefits and avoids some adverse effects of gas insufflation. We developed an irrigating device and apparatus designed for single-incision laparoscopic surgery and tested its advantages and drawbacks during surgery in a porcine model.

Materials and Methods: Six pigs underwent surgical procedures under general anesthesia. A 30-cm extracorporeal cistern was placed over a 5–6-cm abdominal incision. The abdomen was irrigated with warm saline that was drained via a suction tube placed near the surgical field and continuously recirculated through a closed circuit equipped with a hemodialyzer as a filter. Irrigant samples from two pigs were cultured to check for bacterial and fungal contamination. Body weight was measured before and after surgery in four pigs that had not received treatments affecting hemodynamics or causing diuresis.

Results: One-way flow of irrigant ensured laparoscopic vision by rinsing blood from the surgical field. Through a retroperitoneal approach, cystoprostatectomy was successfully performed in three pigs, nephrectomy in two, renal excision in two, and partial nephrectomy in one, under simultaneous ultrasonographic monitoring. Through a transperitoneal approach, liver excision and hemostasis with a bipolar sealing device were performed in three pigs, and bladder pedicle excision was performed in one pig. Bacterial and fungal contamination of the irrigant was observed on the draining side of the circuit, but the filter captured the contaminants. Body weight increased by a median of 2.1% (range, 1.2–4.4%) of initial weight after 3–5 hours of irrigation.

Conclusions: Surgery under irrigation is feasible and practical when performed via a cistern through a small abdominal incision. This method is advantageous, especially in the enabling of continuous and free-angle ultrasound observation of parenchymal organs. Adverse effects of abdominal irrigation need further assessment before use in humans.

Stitching and Surface Reconstruction From Endoscopic Image Sequences: A Review of Applications and Methods

Endoscopic procedures form part of routine clinical practice for minimally invasive examinations and interventions. While they are beneficial for the patient, reducing surgical trauma and making convalescence times shorter, they make orientation and manipulation more challenging for the physician, due to the limited field of view through the endoscope. However, this drawback can be reduced by means of medical image processing and computer vision, using image stitching and surface reconstruction methods to expand the field of view. This paper provides a comprehensive overview of the current state of the art in endoscopic image stitching and surface reconstruction. The literature in the relevant fields of application and algorithmic approaches is surveyed. The technological maturity of the methods and current challenges and trends are analyzed.

URINE FLOW DYNAMICS THROUGH THE URETHRA IN PATIENTS WITH BLADDER OUTLET OBSTRUCTION

Voiding dysfunction is a common disease among the elderly male population. However, few studies have elucidated the flow dynamics of the disease mechanism. We attempted to clarify the fluid dynamics of urine in the prostatic urethra (PU) in patients with bladder outlet obstruction (BOO), a common disease associated with voiding dysfunction. A model of normal PU and three phase models following the BOO progression were prepared using 3D CAD software tracing cystourethroscopic images. In fluid dynamics computation, the normal detrusor pressure was applied to the bladder side in each model. Results of fluid simulation were compared for flow trajectory line, fluid energy dynamics using Bernoulli's principle and pressure loss coefficient. In the BOO model, a large vortex was observed adjacent to the bladder outlet (BO) with increased hydraulic energy loss during the passage through the tract. In contrast, opening of the BO eliminated the vortex with reduction of hydraulic energy loss. These results corresponded with clinical data measured by catheterized pressure sensors inserted into the urethra, and those of urethral diameter measured by urethrography. Fluid dynamics simulation using CAD models can clarify the mechanism of voiding dysfunction in a less invasive and more acceptable way in patients with BOO.

ASSESSMENT OF VOIDING FUNCTION BY ENDOSCOPIC IMAGING — A PRELIMINARY REPORT

We report a novel method of reconstructing the 3D structure of the prostatic urethra and measuring its elasticity using endoscopic video images, and discuss their relation to clinical relevancy. Information regarding pixel color and brightness in the endoscopic video image is converted to relative distance between the object and the light source. An opened, 3D image of the prostatic urethra is obtained from a video image captured by the endoscope as it is slowly pulled through the urethra. The elasticity of the urethra is determined by recording a video image of the endoscope fixed in the prostatic urethra, with and without irrigation under water pressure of approximately 80 cm H 2 O . Angulation of the prostatic urethra is estimated by the number of intersections between the outline of protruded prostate and the midline of the urethra in patients with severe voiding dysfunction scheduled for transurethral resection of prostate, and in those scheduled for transurethral resection of bladder tumor without apparent discomfort during urination. The number of intersections showed a relationship with voiding symptoms. In conclusion, reconstruction of the 3D structure of the prostatic urethra from endoscopic video images is a feasible method that shows promise for estimating the mechanism of voiding dysfunction.

Gasless single-port access endoscopic surgery in urology: minimum incision endoscopic surgery, MIES

Abstract Minimum incision endoscopic surgery (MIES) is a gasless, single-port access, cost-effective, and minimally invasive surgery that has been in development since the late 1990s. Use of MIES has steadily increased in Japan and Asia and has been introduced into Europe and the USA. In 2006, MIES was certified by the Japanese government as an advanced surgery and since 2008 it has been covered by the Japanese universal health insurance system as a new surgical technique. Briefly, MIES involves an initial minimum incision (a single port) that permits extraction of the target specimen. A wide working space through the port is then made by separating the anatomical plane extraperitoneally. This is maintained with special retractors instead of gas insufflation. All instruments including an endoscope are inserted through the port and the operation is completed. The size of the port can be tailored to the situation if necessary, which contributes to preclusion of patient selection. The procedure uses only two disposable devices that are inexpensive, resulting in low equipment costs. Surgeons have the benefits of magnified vision through endoscopy as well as stereovision and panoramic vision of naked eyes through the port, which reduces the technical demands of the procedure. Techniques for two basic MIES procedures allow MIES to be performed for most urological organs and in extraordinary cases by their modifications. Thus, the MIES system permits minimally invasive surgery without use of CO(2) gas, which is ideal from medical, environmental and economic perspectives, is cost-effective and minimizes patient selection.