Water-filled laparoendoscopic surgery (WAFLES): feasibility study in porcine model

Development of Integrated Leader Controller for Forceps/Retractor Manipulation in Single-Port Water-Filled Laparo-Endoscopic Surgery

Single-port water-filled laparo-endoscopic surgery (WaFLES) is a surgical procedure used for treatment in an environment filled with isotonic water in the abdominal cavity under a single-port condition. In this study, we developed two leader controllers for the forceps manipulator and retractor to generate and maintain a surgical workspace for a single-port WaFLES support robot. The development of the specific controller for each device increased the operation time and complicated the motion, such as regripping. We integrated the two functions as a controller to prevent the problem above. We performed grasping and retracting tasks in the virtual surgical workspace to evaluate the proposed controller. Based on the experimental results, we clarified the effect on the operation time by a different mechanism and observed that arranging the switch decreased the operation time. In addition, one of the proposed leader controllers improved operability in terms of operation time during selection and switching from the retractor to the forceps manipulator. However, the arrangement of the switch could adversely affect controller operability when switching from a simple operation (requiring only position control during retractor operation) to a complex operation (requiring both position and posture control during forceps operation). Furthermore, manipulation errors were observed using either of the proposed controllers. Therefore, the sensing procedure of the controller should be improved by addressing these errors in software and hardware.

Physiological and Biochemical Responses to Continuous Saline Irrigation Inside the Abdominal Cavity in Anesthetized Pigs

BACKGROUND

Water-filled laparoendoscopic surgery (WaFLES) has been proposed as a novel surgical system achieving a wide surgical field in the intra- and extraperitoneal space with continuous irrigation of isotonic fluid into the field. Despite its technical feasibility and advantages, the safety of the technique, particularly with respect to physiological functions, has not been evaluated.

METHODS

Various types of minor abdominal surgeries were performed under general anesthesia in nine adult pigs either by conventional laparoscopy (n = 3) or WaFLES (n = 6). In addition to esophageal temperature and body weight, cardiorespiratory variables such as blood pressure, heart rate, and arterial blood gas parameters were compared before and after the surgeries. Blood samples were obtained for assessing changes in biochemical parameters before and after the surgeries.

RESULTS

Three to seven hours of various surgeries were completed without critical cardiorespiratory events in all animals. Oxygenation and ventilation were maintained regardless of the techniques used for the surgeries. A minor increase of body weight (2.5% of initial body weight), metabolic acidosis, hyperkalemia, and impaired hepatic function were observed after WaFLES surgeries.

CONCLUSIONS

The preliminary study indicated no serious immediate adverse effects of the WaFLES technique.

Underwater robotic suturing

BACKGROUND

Laparoscopic and robotic surgeries have become popular, and this popularity is increasing. However, the environment in which such surgeries are performed is rarely discussed. Similar to arthrosurgery performed in water, artificial ascites could be a new environment for laparoscopic surgery. This study was performed to determine whether robotic surgery is applicable to complicated suturing underwater.

MATERIAL AND METHODS

A da Vinci Surgical System S was used. A weighted fabric sheet was placed at the bottom of a tank. Identical sets were made for each environment: One tank was dry, and the other was filled with water. The suturing task involved placement of a running silk suture around the perimeter of a small circle. The task was performed eight times in each environment. The task time and integrity score were determined. The integrity score was calculated by evaluating accuracy, tightness, thread damage, and uniformity; each factor was evaluated using a five-point scale.

RESULTS

Although statistically significant differences were not shown in either task time or integrity score between the underwater and air environments, robotic suturing underwater is not inferior to performance in air.

CONCLUSIONS

The feasibility of robotic suturing underwater was confirmed under the herein-described experimental conditions.

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.

Development of a small sucker manipulator for underwater surgery support

WaFLES (Water-Filled LaparoEndoscopic Surgery) is an operative method suggested by Igarashi et al., which has several advantages, such as, preventing the drying of inner organs, and being able to use ultrasound devices for real time monitoring. However, grasping of inner organs with usual forceps for move and incision purpose is difficult. Therefore our ultimate goal is to develop a small sucker manipulator for WaFLES support. Experiments were conducted to explore suitable suction cups for underwater application, and suitable structure (cup-to-cup distance, elasticity of binding material, layouts of multiple cups) for a multiple-cup assembly, in terms of adsorption force and tolerance to sideslip. Experiment results showed that 1) the shape of each single suction cup for the underwater application was identified; 2) the structure of the multiple-cup assembly affects the adsorption force and tolerance to sideslip.

Saline-filled laparoscopic surgery: A basic study on partial hepatectomy in a rabbit model

BACKGROUND

There is still a poor understanding of the effects of pneumoperitoneum with insufflation of carbon dioxide gas (CO2) on malignant cells, and pneumoperitoneum has a negative impact on cardiopulmonary responses. A novel saline-filled laparoscopic surgery (SAFLS) is proposed, and the technical feasibility of performing saline-filled laparoscopic partial hepatectomy (LPH) was evaluated in a rabbit model.

MATERIAL AND METHODS

Twelve LPH were performed in rabbits, with six procedures performed using an ultrasonic device with CO2 pneumoperitoneum (CO2 group) and six procedures performed using a bipolar resectoscope (RS) in a saline-filled environment (saline group). Resection time, CO2 and saline consumption, vital signs, blood gas analysis, complications, interleukin-1 beta (IL-1β) and C-reactive protein (CRP) levels were measured. The effectiveness of the resections was evaluated by the pathological findings.

RESULTS

LPH was successfully performed with clear observation by irrigation and good control of bleeding by coagulation with RS. There were no significant differences in all perioperative values, IL-1βand CRP levels between the two groups. All pathological specimens of the saline group showed that the resected lesions were coagulated and regenerated as well as in the CO2 group.

CONCLUSIONS

SAFLS is feasible and provides a good surgical view with irrigation and identification of bleeding sites.

GPU based real-time surgical navigation system with three-dimensional ultrasound imaging for water-filled laparo-endoscope surgery

Presently, a variety of navigation systems are employed in clinical treatments involving neurosurgery, ENT, orthopedic, and head and neck surgery. An ultrasound diagnostic system is used as the navigation system for movable and deformable organs in the abdomen or chest. In this study, we developed a real-time updated 3D ultrasound navigation system that facilitates the high-speed transfer of image data and GPGPU processing for fetal surgery and water-filled laparo-endoscopic surgery (WAFLES). Experimental results showed that our system was able to update every 62 ms. Further, in vivo experimental results showed the ability of our system to guide a surgeon to a target organ during WAFLES in a case where the endoscopic view experienced problems.

Positioning error evaluation of GPU-based 3D ultrasound surgical navigation system for moving targets by using optical tracking system

PURPOSE

A near real-time three-dimensional (3D) ultrasound navigation system has been developed for guiding surgery involving internal organs that move and change shape (e.g., abdominal surgery, fetal surgery). In practical applications, significant errors arise between the actual navigation-image positions depending on the time delay of the system. Therefore, the positioning error of the system relative to the target velocity was evaluated.

METHODS

We developed a method for evaluating the positioning error of a graphics processing unit-based 3D ultrasound surgical navigation system (with an optical tracking system) for moving targets. The effectiveness of this system was quantitatively evaluated in terms of its image processing runtime, target registration error (TRE), and positioning error for a moving target. The positioning error was evaluated for a phantom (with an optical tracking marker) moving at speeds of 5-25 mm/s, and the navigation target was the center point of the phantom. The imaging range of the volume data was set to the maximum angle and range of the ultrasound diagnostic system (update rate: 4 Hz).

RESULTS

The image processing runtime was 27.43 ± 4.80 ms, and the TRE was 1.50 ± 0.28 mm. The positioning error was 4.24 ± 0.12 mm for a target moving at a speed of 10 mm/s and 5.36 ± 0.10 mm for one moving at 15 mm/s.

CONCLUSION

The effectiveness of an ultrasound navigation system was quantitatively evaluated by using the positioning error for a moving target. This navigation system demonstrated high calculation speed and positioning accuracy for a moving target. Therefore, it is suitable to guide the surgery of abdominal internal organs (e.g., in fetal and abdominal surgeries) that move or change shape during breathing and surgical approaches.