Trocar Tip Research Articles

Percutaneous elastic-dynamic fixation for the treatment of volar displaced distal radius fractures. A solution for elderly patients?

<p><strong>Aim</strong> <br />The Epibloc elastic-dynamic fixation has been applied for many years at several hand surgery centres in Italy. This technique has been considered safe and reliable in the treatment of distal meta-epiphyseal fractures of the radius with dorsal displacement. The aim of this study was to evaluate an alternative use of this method in the treatment of volar displaced wrist fractures in cases where an internal fixation could not be recommended.<br /><strong>Methods </strong><br />The procedure consisted of two flexible pins with a trocar tip and an external plate for locking fixation with compression.<br />The surgical technique was derived from the original procedure, modifying the placement of the pins and performing small surgical accesses to preserve the neuro-vascular structures of the volar aspect of the wrist. To achieve and preserve the reduction of the volar fragment, a third pin was inserted into the fracture with a similar procedure to Kapandji's reduction technique.<br /><strong>Results</strong> <br />At three-month follow-up, most patients did not experience any pain. In 14 cases, the strength grip was recovered between 75% and 90%, compared to the contralateral hand (Jamar test). In 15 patients, the wrist range of motion was restored with values greater than 100. In 17 cases, forearm pronation-supination was restored to more than 120°.<br /><strong>Conclusion</strong> <br />In cases of non-comminuted, one or two fragments volar displaced wrist fractures, the elastic-dynamic fixation associated with an intrafocal pinning reduction may be proposed as an alternative to open reduction and internal fixation in elderly<br />patients.</p>

Using robotics to move a neurosurgeon's hands to the tip of their endoscope.

A major advantage of surgical robots is that they can reduce the invasiveness of a procedure by enabling the clinician to manipulate tools as they would in open surgery but through small incisions in the body. Neurosurgery has yet to benefit from this advantage. Although clinical robots are available for the least invasive neurosurgical procedures, such as guiding electrode insertion, the most invasive brain surgeries, such as tumor resection, are still performed as open manual procedures. To investigate whether robotics could reduce the invasiveness of major brain surgeries while still providing the manipulation capabilities of open surgery, we created a two-armed joystick-controlled endoscopic robot. To evaluate the efficacy of this robot, we developed a set of neurosurgical skill tasks patterned after the steps of brain tumor resection. We also created a patient-derived brain model for pineal tumors, which are located in the center of the brain and are normally removed by open surgery. In comparison, testing with existing manual endoscopic instrumentation, we found that the robot provided access to a much larger working volume at the trocar tip and enabled bimanual tasks without compression of brain tissue adjacent to the trocar. Furthermore, many tasks could be completed faster with the robot. These results suggest that robotics has the potential to substantially reduce the invasiveness of brain surgery by enabling certain procedures currently performed as open surgery to be converted to endoscopic interventions.

MRI enhances the understanding of critical anatomy during primary laparoscopic port placement.

Despite the majority of laparoscopic visceral injuries occurring with primary entry, high-fidelity training models are lacking. Three healthy volunteers underwent non-contrast 3T MRI at Edinburgh Imaging. A direct entry 12mm trocar was filled with water to improve MR visibility, placed on the skin at entry points, then images were acquired in the supine position. Composite images were created, and distances from the trocar tip to the viscera were measured, demonstrating anatomical relationships during laparoscopic entry. With a BMI of 21 kg/m2, gentle downward pressure during skin incision or trocar entry reduced the distance to the aorta to less than the length of a No. 11 Scalpel blade (22mm). The need for counter-traction and stabilisation of the abdominal wall during incision and entry is demonstrated. With a BMI of 38 kg/m2, deviating from the vertical angle for trocar insertion can result in the entire trocar shaft being placed within the abdominal wall without entering the peritoneum, creating a 'failed entry.' At Palmer's point distance between the skin and bowel is only 20mm. Ensuring the stomach is not distended will minimise gastric injury risk. The use of MRI to provide visualisation of the critical anatomy during primary port entry allows the surgeon to gain better understanding of textually described best practice techniques.

Surgeon estimation of retropubic trocar position in blind 3D space.

Retropubic midurethral sling surgery involves the blind passage of trocars near vital organs. We quantified the proximity of surgeons' mental representation of trocar position relative to actual position using a pelvis simulation platform. We hypothesized that novice surgeons, compared with experts, would estimate the trocar's location to be further from the actual location. Novice and expert surgeons performed bilateral retropubic trocar passes of a Gynecare TVT trocar (#810041B-#810,051) on the simulation platform. We measured the trocar tip's position using a motion capture system, and recorded vocalizations when they perceived contacting the bone and crossing three landmark-oriented planes. We calculated differences (∆Bone, ∆Turn, ∆Top, ∆Pop) between vocalization times and when the trocar crossed the corresponding plane. We performed Mann-Whitney and Chi-squared tests to investigate differences between novices and experts and Levene's test to assess equality of variances for subject-level variation. A total of 34 trials, including 22 expert and 12 novice trials, were performed by six participants. ∆Bone was significantly smaller among novice surgeons (1.27 vs 2.81s, p=0.013). There were no significant differences in the remaining three deltas or in vocalizing early versus late. Levene's test revealed no significant differences in within-subject variability for any of the four deltas. Novices passed the trocar anterior to the pubic bone on three passes. Novices were similar to expert surgeons in their estimation of the trocar's location and may have relied more heavily on anticipatory mechanisms to compensate for lack of experience. Teaching surgeons should make sure the novice surgeon trocar pass starts posterior to the bone.

A case of two connected stents deployed during iStent inject W surgery

BackgroundWe report a case with two connected stents ejected simultaneously during an iStent inject W surgery, a modified second-generation iStent Trabecular Micro-Bypass System.Case presentationA 57-year-old woman with primary open-angle glaucoma underwent a combined cataract and iStent inject W surgery in her left eye. After the trabecular meshwork/Schlemm’s canal was pierced by the trocar of injector, the delivery button was pressed a first time, but the stent was not ejected. After the button was pressed a second time, connected two stents were ejected. After removing the dislocated stents from the anterior chamber, two stents were implanted into the desired places using another injector. Except for mild hyphema, no postoperative complication occurred. Stereomicroscopic observation showed that the two stents were connected by a broken trocar shaft. An X-ray showed that the trocar shaft was broken at the part referred to as the “sprayed trocar”. Scanning electron microscopy showed that the surface features of the broken trocar and trocar tip represented tensile failure.ConclusionsAlthough rare, considering that the damage was seen at the structurally weak part (i.e., sprayed trocar), the same phenomenon can happen. For patient safety, surgeons are recommended to inspect the device when the deployment of either the first or second stent is unsuccessful during the iStent inject surgery.

P-031 AN UNUSUAL CASE OF AN INCARCERATED 5MM PORT SITE HERNIA FOLLOWING LAPAROSCOPIC FUNDOPLICATION

Abstract Aim Port site hernias are a rare, but recognised risk of laparoscopic surgery. Literature supports fascial closure at port sites of 10mm or greater. However, there are few reported cases of herniation through 5mm port sites. Methods This case report focuses on a 67-year-old female who underwent an uncomplicated primary laparoscopic Toupet's fundoplication. 11 days post procedure she presented with an incarcerated port site hernia. CT scan demonstrated high grade small bowel obstruction with a transition point at the site of the 5mm right sided port. A laparotomy was performed, the hernia reduced, small bowel was viable, and the port site hernia was closed internally using vicryl sutures. Results The incidence of 5mm trocar-site hernias is rare. A recent literature review found only 10 such cases related to general surgery (cholecystectomy:6; appendicectomy: 2; right hemicolectomy: 1; paraesophageal hernia:1). Risk factors for port-site hernias include: high BMI, midline position, size, number and type of trocar tip. The limited current literature identifies excessive trocar manipulation as the major risk factor for developing 5mm port-site hernias, yet routine fascial closure is not supported. Conclusion Herniation at 5mm port sites is rare but attention should be paid when patients present with symptoms suggesting its occurrence.

National survey of colorectal surgery units on abdominal wall closure

IntroductionThe purpose of this study is to assess the current status and knowledge of the Spanish colorectal surgeons on the wall closure. MethodsA single answer questionnaire of 25 closed questions was conducted using specific software for online surveys that was distributed to a cohort of colorectal surgeons. Results53 surgeons replied to the survey. The vast majority prefer a closure of the midlaparotomy with a very slow absorbing monofilament (67.92%) continuous suture (96.23%) in a single plane (81.13%). Mass stitches, retention systems, and loop sutures continue to be used. The most commonly used suture gauge was USP 1 (United States Pharmacopeia) (58.49%). The most commonly used needle is with a cylindrical body and a trocar tip. Only 50%, routinely perform wall closure after placement of a trocar equal to or greater than 10 mm. Almost everyone knows the 4:1 rule and thinks it should be applied, but the small bites technique is not performed. 50% would never place a prophylactic prosthesis. The closure is usually performed by the same surgeon who has performed the entire procedure. One out of five confesses not knowing the rate of incisional hernias in his unit. ConclusionThere is a lack of consensus and basic knowledge regarding the technical aspects of closure and the prevention of the appearance of incisional hernias. The use of slow absorbing monofilament continuous suture in a single plane seems well accepted.

Encuesta nacional a unidades de cirugía colorrectal sobre el cierre de pared abdominal

IntroductionThe purpose of this study is to assess the current status and knowledge of the Spanish colorectal surgeons on the wall closure. MethodsA single answer questionnaire of 25 closed questions was conducted using specific software for online surveys that was distributed to a cohort of colorectal surgeons. Results53 surgeons replied to the survey. The vast majority prefer a closure of the midlaparotomy with a very slow absorbing monofilament (67,92%) continuous suture (96,23%) in a single plane (81,13%). Mass stitches, retention systems, and loop sutures continue to be used. The most commonly used suture gauge was USP 1 (United States Pharmacopeia) (58,49%). The most commonly used needle is with a cylindrical body and a trocar tip. Only 50%, routinely perform wall closure after placement of a trocar equal to or greater than 10mm. Almost everyone knows the 4: 1 rule and thinks it should be applied, but the small bites technique is not performed. 50% would never place a prophylactic prosthesis. The closure is usually performed by the same surgeon who has performed the entire procedure. One out of five confesses not knowing the rate of incisional hernias in his unit. ConclusionThere is a lack of consensus and basic knowledge regarding the technical aspects of closure and the prevention of the appearance of incisional hernias. The use of slow absorbing monofilament continuous suture in a single plane seems well accepted.

Single-energy versus dual-energy imaging during CT-guided biopsy using dedicated metal artifact reduction algorithm in an in vivo pig model.

PurposeTo evaluate dual-energy CT (DE) and dedicated metal artifact reduction algorithms (iMAR) during CT-guided biopsy in comparison to single-energy CT (SE).MethodsA trocar was placed in the liver of six pigs. CT acquisitions were performed with SE and dose equivalent DE at four dose levels(1.7–13.5mGy). Iterative reconstructions were performed with and without iMAR. ROIs were placed in four positions e.g. at the trocar tip(TROCAR) and liver parenchyma adjacent to the trocar tip(LIVER-1) by two independent observers for quantitative analysis using CT numbers, noise, SNR and CNR. Qualitative image analysis was performed regarding overall image quality and artifacts generated by iMAR.ResultsThere were no significant differences in CT numbers between DE and SE at TROCAR and LIVER-1 irrespective of iMAR. iMAR significantly reduced metal artifacts at LIVER-1 for all exposure settings for DE and SE(p = 0.02-0.04), but not at TROCAR. SNR, CNR and noise were comparable for DE and SE. SNR was best for high dose levels of 6.7/13.5mGy. Mean difference in the Blant-Altman analysis was -8.43 to 0.36. Cohen’s kappa for qualitative interreader-agreement was 0.901.ConclusionsiMAR independently reduced metal artifacts more effectively and efficiently than CT acquisition in DE at any dose setting and its application is feasible during CT-guided liver biopsy.

A novel three-dimensional printed device to improve the safety of trocar insertion in hypotonous eyes

The force required for trocar insertion in hypotonous eyes can cause significant deformation of the globe and result in an iatrogenic injury to the lens, posterior capsule, or retina from the sharp trocar tip. We developed a device designed to stabilize the globe and provide counterpressure without significant globe deformation during trocar insertion. Our novel device was modeled using computer-aided design software, three-dimensional (3D) printed, and validated in an ex vivo porcine model. The risk of trocar-retinal touch was evaluated by comparing the distance between the trocar tip and opposing retina with either a cotton swab or our 3D printed device. We found an increased distance between the retina and trocar tip at the time of trocar insertion using our novel device: 3.3 ± 1.3 mm (P = 0.035), suggesting an improved safety margin. This device has the potential to improve the safety of trocar insertion in eyes at risk of trocar-associated injury, including hypotonous, previously vitrectomized, and nanophthalmic eyes.

Virtualmonochromatic spectral imaging versus linearly blended dual-energy and single-energy imaging during CT-guided biopsy needle positioning: Optimization of keV settings and impact on image quality.

ObjectivesTo compare image quality and metal artifact reduction between virtual monochromatic spectral imaging (VMSI), linearly blended dual-energy (DE) and single-energy (SE) images, each with and without dedicated iterative metal artifact reduction (iMAR) for CT-guided biopsy.Materials and methodsA biopsy trocar was positioned in the liver of six pigs. DE (Sn140/100kVp) and SE (120kVp/200mAs) acquisitions were performed with equivalent dose. From dual-energy datasets DE Q30-3 images and VMSI between 40–180 keV in steps of 20 keV were generated. From SE datasets I30-3 images were reconstructed. All images were reconstructed with and without iMAR. Objective image quality was analyzed applying density measurements at standardized positions (e.g. trocar tip and liver parenchyma adjacent to the trocar tip) and semi-automated threshold based segmentation. Subjective image quality was performed using semi-quantitative scores. Analyses were performed by two observers.ResultsAt the trocar tip quantitative image analysis revealed significant difference in CT numbers between reconstructions with iMAR compared to reconstructions without iMAR for VMSI at lower keV levels (80 and 100 keV; p = 0.03) and DE (p = 0.03). For liver parenchyma CT numbers were significantly higher in VMSI at high keV compared to low keV (p≤0.01). VMSI at high keV also showed higher CT numbers compared to DE and SE images, though not the level of statistical significance. The best signal-to-noise ratio for VMSI was at 80 keV and comparable to DE and SE. Noise was lowest at 80 keV and lower than in DE and SE. Subjective image quality was best with VMSI at 80 keV regardless of the application of iMAR. iMAR significantly improved image quality at levels of 140 keV and 160 keV. Interreader-agreement was good for quantitative and qualitative analysis.ConclusioniMAR improved image quality in all settings. VMSI with iMAR provided metal artifact reduction and better image quality at 80 keV and thus could improve the accurate positioning in CT-guided needle biopsy. In comparison, DE imaging did not improve image quality compared to SE.

Safe port placement and fixation during neonatal laparoscopy

The neonatal and pediatric abdominal wall offers challenges for work port placement when compared to the adolescent and adult population. A safe technique for work port placement for neonatal laparoscopic procedures is presented. After placement of the optic port in the umbilical area and insufflation is achieved, the abdomen is incised at the desired work port site with a pointed scalpel in the transverse plane. A sharp pointed scissor is then inserted in the wound, in the transverse plane; with the cutting action of the scissor used to penetrate and spread the muscle. This is performed under vision until the peritoneum is reached and breached. Before the scissor is retracted, the blades are spread at the level of the abdominal wall to increase the tract diameter. A port with a blunt trocar tip is then eased through the tract. A Steri-Strip™ (3 M Healthcare, St. Paul, MN) is placed around the port sleeve after insertion of desired length, and a 4-0 Vicryl is used to approximate the excessive skin incision (if present) and secure it to the Steri-Strip™ for secure port fixation. The technique was used in 192 neonates from M = 21.5 days (1–45 days) without any complications of bleeding, internal organ injury, gas escape or dislocation in all procedures. The scissor tract technique allows safe and secure placement of work ports under vision in neonates. It completely eliminates any dangers of injury that may arise from forced application of trocar–port sets in neonates.

Prospective randomized comparison of early versus newer-generation vertebral access devices for kyphoplasty.

Kyphoplasty is an established method of treating osteoporotic vertebral body compression fractures. In recent years, several techniques to enhance the efficiency and outcomes of this surgery have been developed and implemented in clinical practice. In the present study, we assess the impact of two new access instruments on overall operation time and the administered dose area product in comparison with the standard access instrument used in our clinical practice. The two newer comparator devices have been designed with the intention of streamlining intraoperative workflow by omitting several procedural steps. This was a single-center prospective randomized trial investigating three distinct access instruments compatible with the Joline Allevo balloon catheter system. Specifically, two newer access devices marketed as being able to enhance surgical workflow (Joline RapidIntro Vertebra Access Device with a trocar tip and Joline SpeedTrack Vertebra Introducer Device with a short, tapered tip) were compared with the older, established Joline Vertebra Access Device from the same firm. Consecutive eligible and consenting patients scheduled to undergo kyphoplasty for osteoporotic vertebral compression fracture refractory to conservative, medical treatment during the period May 2012-August 2015 were randomized to receive surgery using one of the three devices. Besides the use of the trial instruments, all other preoperative, intraoperative and postoperative care was delivered according to standard practice. 91 kyphoplasties were performed on 65 unique patients during the study period. The median operation time across the three groups was 29min (IQR 22.5-35.5) with a median irradiation time of 2.3min (IQR 1.2-3.4). The median patient age was 74years (IQR 66-80). The groups did not significantly differ in terms of age (p = 0.878), sex (p = 0.37), T score (p = 0.718), BMI (p = 0.285) or the applied volume of cement (p = 0.792). There was no significant difference between the treatment groups with respect to surgical duration (p = 0.157) or dose area product (p = 0.913). Although use of the two newer-generation access instruments were designed to involve fewer unique steps per operation, their use was not associated with reduction in surgical duration, irradiation time or dose area product administered compared with the older, established vertebral access device. Care should be taken to evaluate the impact of new instruments on key surgery-related parameters such as surgical duration and radiation exposure and claims made about new instruments should be assessed a structured fashion.

Augmented reality and artificial intelligence-based navigation during percutaneous vertebroplasty: a pilot randomised clinical trial.

To assess technical feasibility, accuracy, safety and patient radiation exposure of a novel navigational tool integrating augmented reality (AR) and artificial intelligence (AI), during percutaneous vertebroplasty of patients with vertebral compression fractures (VCFs). This prospective parallel randomised open trial compared the trans-pedicular access phase of percutaneous vertebroplasty across two groups of 10 patients, electronically randomised, with symptomatic single-level VCFs. Trocar insertion was performed using AR/AI-guidance with motion compensation in Group A, and standard fluoroscopy in Group B. The primary endpoint was technical feasibility in Group A. Secondary outcomes included the comparison of Groups A and B in terms of accuracy of trocar placement (distance between planned/actual trajectory on sagittal/coronal fluoroscopic images); complications; time for trocar deployment; and radiation dose/fluoroscopy time. Technical feasibility in Group A was 100%. Accuracy in Group A was 1.68 ± 0.25mm (skin entry point), and 1.02 ± 0.26mm (trocar tip) in the sagittal plane, and 1.88 ± 0.28mm (skin entry point) and 0.86 ± 0.17mm (trocar tip) in the coronal plane, without any significant difference compared to Group B (p > 0.05). No complications were observed in the entire population. Time for trocar deployment was significantly longer in Group A (642 ± 210s) than in Group B (336 ± 60s; p = 0.001). Dose-area product and fluoroscopy time were significantly lower in Group A (182.6 ± 106.7mGy cm2 and 5.2 ± 2.6s) than in Group B (367.8 ± 184.7mGy cm2 and 10.4 ± 4.1s; p = 0.025 and 0.005), respectively. AR/AI-guided percutaneous vertebroplasty appears feasible, accurate and safe, and facilitates lower patient radiation exposure compared to standard fluoroscopic guidance. These slides can be retrieved under Electronic Supplementary Material.

The analysis of infusion air misdirection in microincisional vitrectomy

Objective To analyze the pathogenic mechanisms and management methods of infusion air misdirection in microincisional vitrectomy. Methods The data of 440 eyes of 440 cases received vitrectomy from Jan.2016 to Jan.2017 were retrospectively analyzed. There were 412 cases of 23 G vitrectomy and 28 cases of 20 G vitrectomy. Results Infusion air misdirection occurred in 23 G vitrectomy in 15 eyes of 15 cases when performing air-fluid exchange. No case happened in 20 G vitrectomy. Infusion air misdirection was mainly caused by inability of trocar tip to penetrate the vitreous cortex and other factors. The management was released anterior chamber gas and readjusted infusion cannula. Conclusion Infusion air misdirection happens more frequently in 23 G vitrectomy than 20 G vitrectomy(χ2=4.141, P=0.042). This complication can be avoided or treated appropriately if recognized. Key words: Vitrectomy, microincisional; Infusion air misdirection; Air-fluid exchange; Mechanisms; Management

Notched K-wire for low thermal damage bone drilling

The Kirschner wire (K-wire) is a common bone drilling tool in orthopedic surgery to affix fractured bone. Significant heat is produced due to both the cutting and the friction between the K-wire and the bone debris during drilling. Such heat can result in high temperatures, leading to osteonecrosis and other secondary injuries. To reduce thermal injury and other high-temperature associated complications, a new K-wire design with three notches along the three-plane trocar tip fabricated using a thin micro-saw tool is studied. These notches evacuate bone debris and reduce the clogging and heat generation during bone drilling. A set of four K-wires, one without notches and three notched, with depths of 0.5, 0.75, and 1mm, are evaluated. Bone drilling experiments conducted on bovine cortical bone show that notched K-wires could effectively decrease the temperature, thrust force, and torque during bone drilling. K-wires with notches 1mm deep reduced the thrust force and torque by approximately 30%, reduced peak temperatures by 43%, and eliminated blackened burn marks in bone. This study demonstrates that a simple modification of the tip of K-wires can effectively reduce bone temperatures during drilling.

A New Efficient Trocar to Insert the Wound Drainage Tube: Jackson-Pratt Drainage Tube.

Introduction: A trocar is used to pierce the muscle and skin to insert the wound drainage tube into the operating field to drain excess blood and fluid just after the operation.1 However, the handle of the trocar always becomes slippery, making it difficult for the operator to control it. Sometimes, the lack of control of a trocar may lead the trocar tip to protrude forward in an unwanted direction and penetrate into another organ of the patient. Sometimes, the operator could hurt his hand while pulling the trocar out by the sharp edge of trocar tip. In this video clip, we would like to introduce a brand new trocar that can be used to insert the wound drainage tube.Materials and Methods: The new trocar has two quadrangle grips (SUNGWON MEDICAL CO., LTD., Korea Patent; 10-1540199). One of the grips has an embossing surface to prevent the trocar from rotating unnecessarily when the operator pushes the trocar to penetrate the muscle and skin. The upper side of the grip has a sunken surface that helps the operator to direct the trocar tip using tactile sensation in the absence of visibility. The other grip has a smooth surface near the trocar tip to prevent it from slipping when the operator picks, by hand, the trocar that has emerged out of the skin. We measured the roughness and friction of the hand grip of the trocars by using Optical 3D Surface Measurement System and scanning of electron microscope. In addition, we assessed the questionnaires answered by surgeons on three domains, including the unwanted turn of the trocar tip, the unwanted sliding of the trocar grip, and the directivity of the trocar tip. The three domains were calculated by the amount of degree that a surgeon felt ranging across a continuum from 0 to an extreme amount of 10 subscales.Results: This trocar is routinely used for all open procedures. The roughness and friction of the brand new trocar had higher roughness and friction than the old trocar (roughness: 0.4365 ± 0.2664 and 1.9988 ± 0.72783 Ra, p < 0.05; friction: 3.059 ± 0.286 and 3.486 ± 0.428 N, p < 0.05). The questionnaire was attempted by 32 surgeons. The score of the unwanted turn of the previous trocar tip was higher than that of the brand new trocar (6.46 ± 3.09 vs 0.65 ± 1.03, p < 0.001). The score of the unwanted sliding of trocar grip of the previous trocar was higher than that of the new trocar (7.46 ± 1.98 vs 1.50 ± 1.90, p < 0.001). The score of the directivity of the trocar tip of the new trocar was higher than that of the old trocar (8.93 ± 1.47 vs 3.09 ± 2.30, p < 0.001).Conclusion: Trocar insertion using the new trocar that has quadrangle grips with sanding surface is an efficient and feasible technique for patients and surgeons.Acknowledgments: The authors thank the members of the medical device clinical trial center of Chonbuk National University Hospital for helpful discussions. This research was also supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (Grant No.: HI15C1529). However, the Ministry of Health & Welfare, Republic of Korea, had no role in design or conduct of the study, including collection, management, analysis, or interpretation of the data in addition to preparation, review, or approval of the article.J.K.P. has patent of this trocar and the patent was transferred to SUNGWON MEDICAL device company. The other authors have nothing to disclose. SUNGWON MEDICAL device company had no role in design or conduct of the study, including collection, management, analysis, or interpretation of the data in addition to preparation, review, or approval of the article.Runtime of video: 3 mins

Deflection Analysis of Different Needle Designs for Prostate Biopsy and Focal Therapy.

The biopsy needles currently used were designed for a transrectal biopsy and are known to experience significant deflection from the point of entry into the gland to the needle tip. Five designs were selected for testing: 18-gauge Bard, 15-gauge lancet tip needle with 12° vet-point cannula, and trocar tip needle with 12°, 15°, and 20° vet-point cannulas. The 15-gauge needle was designed to take a variable specimen sample between 20 and 60 mm, whereas the Bard needle specimen bed was fixed at 20 mm. The needles were bench tested on a spring-loaded platform and fired into gelatin matrix with modulus of elasticity similar to human prostate. The Bard device with lancet tip needle deflected an average of 0.9 mm (range 0.3-1.3 mm) and 1.9° (range 0.6°-2.8°). Increasing needle diameter from 18-gauge Bard to 15-gauge variable with the same lancet tip needle design resulted in an average deflection across the 3 test lengths of 0.9 mm (range 0-2.0 mm) and 0.9° (range 0°-2.0°) with no significant difference. On the contrary, the use of the 3-point trocar tip needles with 12°, 15°, and 20° vet-point cannulas demonstrated significant reduction in the extent of deflection in both millimeters and degrees. There was no deflection at the 2- and 4-cm shots for both spring loads and preloads for the 3 vet tip angles tested. At 6 cm, the 20° vet tip performed the best. We proposed a mechanism that provides more accurate prostate sampling by combining a 3-point trocar tip on the needle with a 20° vet tip on the cutting cannula. Using the phantom, mimicking prostate gland tissue density, no deflection was revealed between 20- and 60-mm biopsy lengths, which should permit a straight sample in the majority of prostate glands and improve cancer localization for focal therapy planning.

트로카 고정부에 작용하는 반력을 측정하여 수술도구 말단의 수직방향 상호작용 힘을 추정하는 방법

This paper proposes a method to estimate vertical interaction force to the end of the surgical instrument by measuring reaction force at the part supporting the trocar. Relation between the force to the trocar and the interaction force is derived using the beam theory. The vertical interaction force is modeled as a function of the reaction force to the trocar and the distance between the drape plate and the trocar. Experimental results show that error is induced by the asymmetric shape of the trocar tip because contact position between the instrument and the trocar tip is changed depending on the direction of the interaction force. The theoretical relation, therefore, is compensated and reduced. Average <TEX>$L_2$</TEX> relative error of the estimated force in the x-direction and the y-direction is 5.81 % and 5.99 %, respectively.

Reducing the risk of trocar site hernias

BACKGROUND Trocar site hernias (TSHs) can affect the outcome of laparoscopic surgery in 0.2–3.1% of cases. Factors influencing the development of TSHs include: the number and diameters of trocars; a peritoneal defect greater than the trocar size; midline insertion; the type of trocar tip; manipulation of the trocar site; methods of entry and closure; operative time; infection at the trocar site. TSHs may have an early or late onset. In early onset TSHs, viscera herniate through the peritoneal defect in the first few days after surgery. In late onset TSHs, the peritoneum remains intact and viscera herniate with the peritoneum. TSHs are usually asymptomatic. Occasionally, they can present with bowel obstruction that necessitates emergency surgery.