Optimizing working space in laparoscopy: CT-measurement of the effect of neuromuscular blockade and its reversal in a porcine model

3D printed cannulas for use in laparoscopic surgery in feline patients: A cadaveric study and case series

OBJECTIVE

To evaluate custom 3D printed laparoscopic cannulas (3DPC) in a feline cadaveric abdominal surgery model and report their use in two live feline subjects.

STUDY DESIGN

Experimental cadaver study, live subject case series.

ANIMALS

Ten feline cadavers; two feline subjects.

METHODS

Custom 3DPCs were initially modeled in a PLA filament material and then created in an autoclavable dental resin for use in live patients. The surgery time, number of surgical collisions and cannula complications were recorded during cadaver procedures before and after use of 3DPCs. Cannula complications were recorded during live procedures and patients were followed to suture removal to record any incisional complications.

RESULTS

There was a significant reduction in mean surgical time (125.6 vs. 95.2 min, p = 0.03), mean number of instrument collisions (6.8 vs. 2.6, p = 0.03), and mean number of cannula complications (10 vs. 2.2, p = 0.03) with the use of only 3DPCs during the procedure. During the live procedures the use of the 3DPCs was successful and no postoperative complications occurred at the incision sites.

CONCLUSION

The use of customized 3DPCs may improve surgical dexterity and decrease complications in advanced procedures and was not associated with any clinical complications in two cats. The use of 3DPCs in veterinary medicine may allow for wider practice of laparoscopic techniques in small animals.

MRI measurement of the effects of moderate and deep neuromuscular blockade on the abdominal working space during laparoscopic surgery, a clinical study

BACKGROUND

Conflicting data exist regarding the effects of deep neuromuscular blockade (NMB) on abdominal dimensions during laparoscopic procedures. We performed a clinical study to establish the influence of moderate and deep neuromuscular blockade (NMB) on the abdominal working space, measured by Magnetic Resonance Imaging (MRI), during laparoscopic donor nephrectomy with standard pressure (12 mmHg) pneumoperitoneum under sevoflurane anaesthesia.

METHODS

Ten patients were intraoperatively scanned three times in the lateral decubitus position, with pneumoperitoneum maintained by a mobile insufflator. The first scan without NMB (T1) was followed by scans with moderate (T2) and deep NMB (T3). The skin-sacral promontory (S-SP) distance was measured, and 3D pneumoperitoneum volumes were reconstructed.

RESULTS

The mean difference in the S-SP distance was -0.32 cm between T2 and T3 (95% CI -1.06 - 0.42 cm; p = 0.344) and + 2.1 cm between T1 and T2 (95% CI 0.81 - 3.39 cm; p = 0.006). The mean differences in pneumoperitoneum volume were 166 mL between T2 and T3 (95% CI, 5 - 327 mL; p = 0.044) and 108 mL between T1 and T2 (95% CI, -273 - 488 mL; p = 0.525). The pneumoperitoneum volume showed high inter-individual variability and no increase in three patients with a high volume at T1.

CONCLUSIONS

During laparoscopic surgery in the lateral decubitus position with standard pressure under sevoflurane anaesthesia, deep NMB did not increase the S-SP distance compared to moderate NMB. Moderate NMB increased the S-SP distance by a mean of 2.1 cm (15.2%) compared with no NMB. The mean pneumoperitoneum volume increased slightly from moderate to deep NMB, with high inter-individual variability.

TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT03287388.

Conversion Rate in Pediatric Robotic-Assisted Surgery: Looking for the Culprit

Introduction: Robotic-assisted surgery (RAS) is increasingly used in adulthood but its application in pediatric population is limited. We report our initial experience in pediatric RAS, focusing on conversions to analyze their causes. Methods: All pediatric patients who underwent RAS between June 2015 and April 2019 were included, analyzing demographics, comorbidities, previous surgery, and intraoperative surgical and anesthetic parameters. A three-arms robotic technique was used in all cases. Additional laparoscopic ports were added, when needed. The surgical team did not change during the program, whereas the anesthesiology team varied. Results: Thirty-nine patients (23 females, 16 males; mean age ± SD = 9.33 ± 4.73 years [range = 1-16]; mean weight ± SD = 35.2 ± 20.0 kg [range = 9-85]) underwent 40 different procedures (18 gastrointestinal, 15 urogynecological, 5 oncological, and 2 miscellaneous). Three procedures (7.5%) were converted to open surgery for inadequate working space (two marked bowel distension and one insufficient hepatic retraction). Converted patients were of significant lower age (mean ± standard error of mean [SEM] = 2.97 ± 1.03 versus 9.83 ± 0.77 years, P = .01) and lower weight (mean ± SEM = 11.83 ± 1.74 versus 35.47 ± 3.16 kg, P = .03). The two groups did not differ statistically for duration of facial mask ventilation before intubation (mean ± SEM = converted 10.67 ± 2.33 versus completed 10.31 ± 0.91 minutes), neuromuscular block dosage (rocuronium; mean ± SEM = converted 0.46 ± 0.06 mg/kg versus completed 0.62 ± 0.03 mg/kg) and in the type of bowel preparation (mechanical and/or pharmacological). Discussion: Conversion rate in initial pediatric RAS program is acceptable. In children, the need for conversion is mainly because of inadequate working space, particularly in smaller children, but it seems not to be influenced by measurable anesthetic factors or different regimen for bowel preparation.

Retroperitoneal Laparoscopy in Dogs: Access Technique, Working Space, and Surgical Anatomy

Objective

To develop and describe a laparoscopic retroperitoneal access technique, investigate working space establishment, and describe the surgical anatomy in the retroperitoneal space as an initial step for clinical application of retroperitoneal laparoscopy in dogs.

Study Design

Cadaveric and experimental study.

Animals

Cadaveric (n=8) and healthy (n=6) adult dogs.

Methods

The retroperitoneal access technique was developed in 3 cadavers based on the human technique and transperitoneal observation. Its application and working space establishment with carbon dioxide (CO₂) insufflation alone was evaluated in 5 cadavers by observing with a transperitoneal telescope and in 6 live dogs by repeated computed tomography (CT) scans at pressure of 0, 5, 10, and 15 mmHg. Recordings of retroperitoneoscopy as well as working space volume and linear dimensions measured on CT images were analyzed.

Results

Retroperitoneal access and working space establishment with CO₂ insufflation alone were successfully performed in all 6 live dogs. The only complication observed was in 1 dog that developed subclinical pneumomediastinum. As pressure increased, working space was established from the ipsilateral to the contralateral side, and peritoneal tearing eventually developed. Working space volume increased significantly from 5 mmHg and linear dimensions increased significantly from 0 to 10 mmHg. With pneumo‐retroperitoneum above 5 mmHg, retroperitoneal organs, including kidneys and adrenal glands, were easily visualized.

Conclusion

The retroperitoneal access technique and working space establishment with CO₂ insufflation starting with 5 mmHg and increasing to 10 mmHg provided adequate working space and visualization of retroperitoneal organs, which may allow direct access for retroperitoneal laparoscopy in dogs.

Design of Virtual Fixtures for Robotic Cholecystectomy

BACKGROUND AND OBJECTIVE

With the ongoing developments in robotic surgery, the associated adverse events need to be carefully evaluated. Virtual fixtures (VFs), a safety design feature against unintended motion during robotic surgery, have been proposed, but the methodology for designing VFs remains experimental. In this study, we propose a novel methodology for designing VFs for robotic cholecystectomy.

MATERIALS AND METHODS

Laparoscopic cholecystectomy (LC) was performed in 24 patients with cholecystitis. Active working space (AWS), the distance between instrument heads (DBIH), motion speed of bilateral hands, and instrument heads were calculated and analyzed.

RESULTS

DBIH was 14.78 ± 6.94 cm. Diameter of right and left AWS was 15.81 ± 3.69 cm and 15.33 ± 1.52 cm, respectively. DBIH was found to significantly correlate with the surgeon's experience. Bilateral AWS was found to be significantly associated with body circumference at Murphy's point level. However, no association was observed between bilateral AWS and surgeon's experience.

CONCLUSIONS

A novel methodology to build VFs for designing VFs for robotic cholecystectomy is established. Surgeon's experience appears to play an important role in determining the DBIH during robotic laparoscopic cholecystectomy, but does not affect bilateral AWS.