The use of water-jet dissection in open and laparoscopic liver resection

Experimental and numerical investigation of waterjet interaction with liver in connection with surgical technique

Hepatectomy, or liver resection, is a process by which through surgery part or all of the liver is removed. In this operation, less bleeding, negligible damage and fast removal are the most important requirements. Surgery through waterjet is one of the most efficient techniques which is widely used in hepatectomy. Some clinical studies are conducted to investigate waterjet method in liver resection. In the present study interaction of waterjet with liver during the process of the surgery is investigated in terms of mechanical engineering. For this purpose, a system of waterjet is designed to consider the interaction of waterjet with liver at different nozzle diameter and velocities. For validation, SPH-FEM model is used to analyze waterjet interaction with hyperelastic liver. In this model, liver cutting is simulated using element deletion defined by a subroutine code based on maximum principal strain criterion. Depth of cut along with degraded volume are measured experimentally and compared with simulated method. Results show that good agreement exists between experimental and simulation finding. By comparing depth of cut in the experimental and simulation results, it can be seen that liver behavior changes from brittle to ductile by increasing waterjet velocity during the experimental tests. For the simulation, maximum principal strain threshold is set to be between 0.1 and 0.4. However, the best agreement between experimental and simulation results exists at maximum principal strain threshold equal to 0.2. The findings can help surgeons to find the best working range of waterjet device and the most efficient operation.

A Multicenter, Open-Label, Single-Arm Phase I Trial of Dual-Wield Parenchymal Transection: A New Technique of Liver Resection Using the Cavitron Ultrasonic Surgical Aspirator and Water-Jet Scalpel Simultaneously (HiSCO-14 Trial)

PURPOSE

This study evaluated the safety and feasibility of a technique of liver resection named dual-wield parenchymal transection technique (DWT), using cavitron ultrasonic surgical aspirator (CUSA) and water-jet scalpel simultaneously.

METHODS

This multicenter, prospective, open-label, and single-arm phase I trial included patients aged 20 years or older with hepatic tumors indicated for surgical resection and scheduled for open radical resection. This study was conducted at two institutions affiliated with the Hiroshima Surgical Study Group of Clinical Oncology (HiSCO). The primary endpoint was the proportion of massive intraoperative blood loss (≥ 1000 mL). The secondary endpoints were the amount of blood loss, operative time, parenchymal transection speed, postoperative complications, and mortality. The safety endpoints were device failure and adverse events associated with devices.

RESULTS

From June 2022 to May 2023, 20 patients were enrolled; one was excluded and 19 were included in the full analysis set (FAS). In the FAS, segmentectomy was performed in nine cases, sectionectomy in four cases, and hemihepatectomy in six cases. Radical resection was achieved in all patients. Intraoperative blood loss greater than 1000 mL was observed in five patients (26.3%). The median amount of blood loss was 545 mL (range, 180-4413), and blood transfusions were performed on two patients (10.5%). The median operative time was 346 minutes (range, 238-543) and the median parenchymal transection speed was 1.2 cm2/minute (range, 0.5-5.1). Postoperative complications of Clavien-Dindo classification ≥ Grade 3 occurred in four patients (21.1%). No mortalities occurred in this study. In the safety analysis, there were no device failures or adverse events associated with devices.

CONCLUSIONS

This study demonstrated the safety and feasibility of DWT for liver resection. The efficacy of the DWT will be evaluated in future clinical trials.

Laparoscopic Liver Resection Utilizing a Water Jet Scalpel for Patients With Liver Fibrosis

Introduction A variety of devices are utilized in order to resect liver parenchyma in laparoscopic liver resection. However, liver fibrosis makes hepatectomy problematic because the liver is rigid and prone to bleeding. The water jet scalpel, which dissociates the liver parenchyma with a jet stream has no thermal damage and is clinically utilized in liver resection, but its safety and efficacy during laparoscopic liver resection for patients with liver fibrosis remain unknown. Methods We analyzed patients who underwent laparoscopic liver resection utilizing the water jet scalpel with liver fibrosis at our hospital. A water jet scalpel was used for liver parenchymal transection, and a saline-linked ball-tipped electrocautery was simultaneously used for hemostasis. Results Subsectionectomy was one case, left lateral sectionectomy was two cases, and non-anatomical liver resection was three cases. The median blood loss was 70 mL (24-104 mL). There was no need for the intraoperative Pringle's maneuver. No perioperative blood transfusion was performed, and there were no postoperative complications, including posthepatectomy liver failure. Conclusion It was suggested that laparoscopic liver resection in patients with liver fibrosis can be safely performed with the water jet scalpel.

Reduction of Blood Loss by Means of the Cavitron Ultrasonic Surgical Aspirator for Thoracoscopic Salvage Anatomic Lung Resections

In centrally located lung tumors, salvage pulmonary resections pose challenges due to adhesions between the pulmonary parenchyma, chest wall, and hilum. This study aimed to investigate the surgical outcomes associated with Cavitron Ultrasonic Surgical Aspirator (CUSA) usage in thoracoscopic salvage pulmonary resections. Patients with centrally located advanced-stage lung tumors who underwent salvage anatomic resections following systemic or radiotherapy were included. They were categorized into CUSA and non-CUSA groups, and perioperative parameters and surgical outcomes were analyzed. Results: The study included 7 patients in the CUSA group and 15 in the non-CUSA group. Despite a longer median surgical time in the CUSA group (3.8 h vs. 6.0 h, p = 0.021), there was a significant reduction in blood loss (100 mL vs. 250 mL, p = 0.014). Multivariate analyses revealed that the use of CUSA and radiotherapy had opposing effects on blood loss (β: -296.7, 95% CI: -24.8 to -568.6, p = 0.034 and β: 282.9, 95% CI: 19.7 to 546.3, p = 0.037, respectively). In conclusion, while using CUSA in the salvage anatomic resection of centrally located lung cancer may result in a longer surgical time, it is crucial in minimizing blood loss during the procedure.

Influence of the water jet system vs cavitron ultrasonic surgical aspirator for liver resection on the remnant liver

BACKGROUND

Several methods, such as finger fracture, Pean crush, cavitron ultrasonic surgical aspirator (CUSA), and water jet (WJ), are used for hepatic parenchymal dissection in liver surgery. CUSA is the conventional method in Japan. WJ is a relatively novel method for parenchymal dissection. Although it has several advantages, such as lower volume of blood loss and shorter operative time, the effect of the WJ system for hepatic dissection on the remnant liver has not yet been investigated.

AIM

To investigate and compare the effect of the WJ method vs CUSA on the remnant liver cut surface.

METHODS

This observational study compared the two types of parenchymal transection methods (WJ vs CUSA) in liver surgery. In total, 24 and 40 patients who underwent hepatectomy using the WJ method and CUSA, respectively, were included in the analysis. Accordingly, the clinicopathological characteristics and clinical outcomes of 24 and 40 patients were compared. Furthermore, postoperative contrast-enhanced computed tomography (CT) scan was performed to assess the cut surface length of the remnant liver and the degenerative thickness of the areas with a reduced contrast effect in the dissected plane. Then, the two groups were compared.

RESULTS

On CT scan, the median areas of denaturation in the liver dissection planes were 522 (range: 109.5-1242) mm² in the CUSA group and 324 (range: 93.6-1529) mm² in the WJ group. The area did not significantly differ between the two groups; however, the denaturation thickness of the WJ group was significantly lower than that of the CUSA group [5.8 (range: 0.7-11.1) mm vs 3.3 (range: 1.7-10.4) mm, P < 0.001].

CONCLUSION

The WJ group had significantly thinner contrast-enhanced areas in the post hepatectomy detached section than the CUSA group.

Feasibility Study to Determine if Microfracture Surgery Using Water Jet Drilling Is Potentially Safe for Talar Chondral Defects in a Caprine Model

OBJECTIVE

Surgical microfracture is considered a first-line treatment for talar osteochondral defects. However, current rigid awls and drills limit access to all locations in human joints and increase risk of heat necrosis of bone. Using a flexible water jet instrument to drill holes can improve the reachability of the defect without inducing thermal damage. The aim of this feasibility study is to determine whether water jet drilling is potentially safe compared with conventional microfracture awls by studying side effects and perioperative complications, as well as the quality of cartilage repair tissue.

DESIGN

Talar chondral defects with 6-mm diameter were created bilaterally in 6 goats (12 samples). One defect in each goat was treated with microfracture created with conventional awls, the contralateral defect was treated with holes created with 5-second water jet bursts at a pressure of 50 MPa. Postoperative complications were recorded and after 24 weeks analyses were performed using the ICRS (International Cartilage Repair Society) macroscopic score and modified O'Driscoll histological score.

RESULTS

Several practical issues using the water jet in the operating theatre were noted. Water jet drilling resulted in fibrocartilage repair tissue similar to the repair tissue from conventional awls.

CONCLUSIONS

These results suggest that water jet drilling gives adequate fibrocartilage repair tissue. Furthermore, the results highlight essential prerequisites for safe application of surgical water jet drilling: stable water pressure, water jet beam coherence, stable positioning of the nozzle head when jetting, and minimizing excessive fluid extravasation.

A Flexible Cystoscope Based on Hydrodynamic Cavitation for Tumor Tissue Ablation

OBJECTIVE

Hydrodynamic cavitation is characterized by the formation of bubbles inside a flow due to local reduction of pressure below the saturation vapor pressure. The resulting growth and violent collapse of bubbles lead to a huge amount of released energy. This energy can be implemented in different fields such as heat transfer enhancement, wastewater treatment and chemical reactions. In this study, a cystoscope based on small scale hydrodynamic cavitation was designed and fabricated to exploit the destructive energy of cavitation bubbles for treatment of tumor tissues. The developed device is equipped with a control system, which regulates the movement of the cystoscope in different directions. According to our experiments, the fabricated cystoscope was able to locate the target and expose cavitating flow to the target continuously and accurately. The designed cavitation probe embedded into the cystoscope caused a significant damage to prostate cancer and bladder cancer tissues within less than 15 minutes. The results of our experiments showed that the cavitation probe could be easily coupled with endoscopic devices because of its small diameter. We successfully integrated a biomedical camera, a suction tube, tendon cables, and the cavitation probe into a 6.7 mm diameter cystoscope, which could be controlled smoothly and accurately via a control system. The developed device is considered as a mechanical ablation therapy, can be a solid alternative for minimally invasive tissue ablation methods such as radiofrequency (RF) and laser ablation, and could have lower side effects compared to ultrasound therapy and cryoablation.

Water jet as a novel technique for enamel drilling ex vivo

To investigate the usage of a water jet for enamel drilling ex vivo, 210 individual extracted molars without lesions or fillings were collected. Then, the specimens were drilled by a water jet or a high-speed dental drill. The cavities of 50 teeth were reconstructed digitally by micro-computed tomography (micro-CT) to measure the height and width. The cavities of 10 teeth were longitudinally incised and their surfaces were observed by scanning electronic microscopy (SEM). After the cavities were filled, 50 fillings were vertically incised. The bonding interface between tooth and filling was observed by SEM. 50 teeth with fillings were stained in 0.1% rhodamine B solution, and then the dye penetration between tooth and filling was observed under the stereomicroscope and confocal laser scanning microscopy (CLSM). The bonding strength between enamel and filling of 50 teeth was simulated and predicted with finite element analysis (FEA). At 140-150 MPa and for 2-3 s, cavities were made with a depth of approximately 764 μm in each tooth. SEM showed the cavity surface in the water jet group had a more irregular concave and convex structure than that in the high-speed dental drill group. There was a trend that the microleakage and bonding width was smaller in the water jet group than in the high-speed dental drill group. FEA indicated that the stress on the resin surface was greater than on the enamel surface in the water jet group. Compared with the tooth drilled by a high-speed dental drill, the tooth drilled by a water jet gained better retention of the filling material and suffered less bonding strength on the enamel surface. Water jet drilling is effective for enamel drilling.

Feasibility of Microwave-Based Scissors and Tweezers in Partial Hepatectomy: An Initial Assessment on Canine Model

Purpose: This study aimed to assess the feasibility of partial hepatectomy (PH) simplified by using microwave-based devices in animal experiments.

Methods: PH was performed on 16 beagles using either Acrosurg Scissors (AS) or Acrosurg Tweezers (AT) without hepatic pedicle (HP) control. Parenchymal transection time, Glissonean pedicle (GP) seal time, bleeding volume, bile leak, and burst pressure were recorded. Probable complications were investigated after 4 weeks.

Results: Transection time (6.5 [6.0–7.6] vs. 11.8 [10.5–20.2] min, p < 0.001) with AT were significantly shorter than with AS. GP sealing times (60 [55–60] vs. 57 [46–91] s, p = 0.859) by both devices were nearly similar. Bleeding volume in the AT group was approximately one-fourth of that in the AS group (6.7 [1.4–22] vs. 28.8 [5.8–48] mL, p = 0.247). AT created higher burst pressure on the bile duct stumps (p = 0.0161). The two devices did not differ significantly in morbidity and mortality after four-week follow-up.

Conclusion: Acrosurg devices achieved a safe PH without HP control owing to microwave-based sealing. AS could be used alone in PH, whereas the clamp-crushing function of AT seemed more advantageous in reducing the transection time and blood loss.

[Blood-saving technologies in extensive liver resections]

The researches devoted to blood-saving technologies in extensive liver resections are analyzed in the manuscript. Resection of three and more liver segments is effective method of surgical treatment of various focal liver lesions. Surgical (anatomical resection with hilar glissonean access, Pringle maneuver, modern technical equipment, etc.), anesthesiological (reduction of central venous pressure, hemostatic agents) and transfusion (autologous blood donation, transfusion, cell saver, etc.) methods contribute to prevention and reduction of blood loss. Intraoperative measures for blood loss prevention should include adequate surgical incision and liver mobilization, precise techniques of parenchymal dissection (for example, cavitation surgical aspirator-destructor), use of clip applicators and local or systemic hemostatic agents.

Anatomic Indications for Using Actuator-driven Pulsed Water Jet for Hepatectomy

BACKGROUND

The clamp crushing method and the use of the Cavitron ultrasonic surgical aspirator (CUSA) are widely accepted techniques for hepatic parenchymal transection. The actuator-driven pulsed water jet (ADPJ) with high tissue selectivity is a new technology that was shown as a safe transection tool in preclinical models, although not much is known about its safety criteria in patients. Therefore, its strongest advantage, the best indications for its use, and its performance in comparison with other transection methods remain to be clarified. In this report, we present several representative cases to help answer these questions.

METHODS

We started using the ADPJ in December 2017, only in cases where the tumor was very close to major vessels or attached to them, along a considerable length, to preserve vessels and prevent postoperative liver failure. All the cases underwent highly demanding procedures. We avoided using this device in cases such as liver cirrhosis, where the hepatic parenchyma was very hard.

RESULTS

Six cases fulfilled our limited indications for using ADPJ. The median age and number of tumors were 55 years (10 to 69 y) and 2.5 years (1 to 4 y), respectively. The mean tumor size was 7.8 cm (2.8 to 21 cm), the minimum distance between the tumor and major vessels to be preserved was 0 mm (0 to 4 mm), and the contact length of the tumor and major vessels was 26 mm (19 to 40 mm). Regarding the surgical outcome, the median operation time and blood loss were 559 minutes (508 to 919 min) and 620 mL (230 to 860 mL), respectively. We achieved a negative surgical margin (R0 resection) in all cases.

CONCLUSIONS

Using ADPJ, we could perform R0 hepatectomy in all cases, which preoperatively were considered to have a high chance of being margin positive. We consider the best indication for using ADPJ is when the tumor and vessels to be preserved are attached or very close over a long distance.

Predictive mechanics-based model for depth of cut (DOC) of waterjet in soft tissue for waterjet-assisted medical applications

The use of waterjet technology is now prevalent in medical applications including surgery, soft tissue resection, bone cutting, waterjet steerable needles, and wound debridement. The depth of the cut (DOC) of a waterjet in soft tissue is an important parameter that should be predicted in these applications. For instance, for waterjet-assisted surgery, selective cutting of tissue layers is a must to avoid damage to deeper tissue layers. For our proposed fracture-directed waterjet steerable needles, predicting the cut depth of the waterjet in soft tissue is important to develop an accurate motion model, as well as control algorithms for this class of steerable needles. To date, most of the proposed models are only valid in the conditions of the experiments and if the soft tissue or the system properties change, the models will become invalid. The model proposed in this paper is formulated to allow for variation in parameters related to both the waterjet geometry and the tissue. In this paper, first the cut depths of waterjet in soft tissue simulants are measured experimentally, and the effect of tissue stiffness, waterjet velocity, and nozzle diameter are studied on DOC. Then, a model based on the properties of the tissue and the waterjet is proposed to predict the DOC of waterjet in soft tissue. In order to verify the model, soft tissue properties (constitutive response and fracture toughness) are measured using low strain rate compression tests, Split-Hopkinson-Pressure-Bar (SHPB) tests, and fracture toughness tests. The results show that the proposed model can predict the DOC of waterjet in soft tissue with acceptable accuracy if the tissue and waterjet properties are known. Graphical Abstract (Left) An overview of the problems of traditional steerable needles and the solutions provided by waterjet steerable needles. (A) Traditional tip-steerable needles and tip-bent needles suffer from poor curvature, especially in soft tissues. (B) Traditional steerable needles are unable to accomplish many bends because the cutting force only results from drastic tissue deformation. (C) The first step for realization of waterjet steerable needles is to understand and model the interaction between waterjet and soft tissues at the tip (predictive model for depth of cut). (D) Then, the equilibrium between shapes cut in the tissue and the straight elastic needle should be understood. (Right) Waterjet steerable needles in which the direction of the tissue fracture is contr olled by waterjet and then the flexible needle follows. The first step for waterjet steerable needle realization is to predict the depth of waterjet cut.

A novel waterjet technology for transurethral cystoscopic injection of viable cells in the urethral sphincter complex

AIMS

In a recent preclinical study, we noticed that injection of cells in the urethral sphincter by needle through a cystoscope under visual control frequently yielded in misplacement or loss of cells. We, therefore, investigated if a needle-free waterjet device delivers viable cells under defined settings, including injection volume and pressure, fluid velocity and transportation media, precisely through the urothelium and connective tissue close to the sphincter muscle without full penetration of the sphincter apparatus.

METHODS

Mesenchymal stromal cells (MSCs) were prepared for needle-free waterjet injections. Upon injections into liquids cell viability and yield were investigated by trypan blue dye exclusion. Upon injection into cadaveric urethral tissue samples, cells were isolated from the urethrae and expanded to prove that this novel method delivered viable cells into the tissue. MSC injections by William's needle served as controls.

RESULTS

Waterjet injections of MSCs into isotonic cell culture medium resulted in equal or better yields of viable cells when compared with needle injections. Upon injection in urethral tissue samples, the waterjet technology facilitated fast and precise injections of viable cells through urothelial, mucosal and submucosal layers to reach the sphincter muscle. By controlling the injection pressure, loss of cells due to insufficient thrust or unintended full penetration was avoided.

CONCLUSIONS

Needle-free waterjet injections deliver cells in the urethra faster and more precisely when compared with needle injections without compromising their viability. This is the first proof-of-concept study providing evidence that a waterjet transports viable cells precisely into the targeted tissue.

An overview of thermal necrosis: present and future

Introduction: Many orthopaedic procedures require drilling of bone, especially fracture repair cases. Bone drilling results in heat generation due to the friction between the bone and the drill bit. A high-level of heat generation kills bone cells. Bone cell death results in resorption of bone around bone screws.Methods: We searched in the literature for data on parameters that influence drilling bone and could lead to thermal necrosis. The points of view of many orthopaedists and neurosurgeons based upon on previous practices and clinical experience are presented.Results: Several potential complications that lead to thermal necrosis are discussed and highlighted.Discussion: Even in the face of growing evidence as to the negative effects of heat induction during drilling, simple and effective methods for monitoring and cooling in real-time are not in widespread usage today. For that purpose, we propose some suggestions for the future of bone drilling, taking note of recent advances in autonomous robotics, intelligent systems and computer simulation techniques.Conclusions: These advances in prevention of thermal necrosis during bone drilling surgery are expected to reduce the risk of patient injury and costs for the health service.

Evolving Technologies for Tissue Cutting

This article reviews evolving and lesser known technologies for tissue cutting and their application in oral and maxillofacial surgery.

Experience and outcomes in living donor liver procurement using the water jet scalpel

BACKGROUND

The aim of the present study was to clarify treatment outcomes of living donor liver procurement using the water jet scalpel (WJS).

METHODS

This single-center, retrospective cohort study included 40 living donors who underwent liver procurement from January 2014 to December 2018. One living donor who underwent posterior segmentectomy was excluded. Clinical data and outcomes after surgery for 20 WJS donors and 19 Cavitron Ultrasonic Surgical Aspirator (CUSA) donors were compared.

RESULTS

Preoperative and excised graft data did not differ significantly between the WJS and CUSA groups. Operation time (P = 0.025) and parenchymal transection time (P = 0.007) were significantly shorter in the WJS group. There was no difference between the groups in terms of short-term outcomes after surgery. Multivariate analysis revealed that WJS offered significant advantages over CUSA in terms of shortening parenchymal transection time (P = 0.017).

CONCLUSION

Living donor liver procurement using WJS contributes to shortening of parenchymal transection time while maintaining the same level of safety as when using CUSA.

Bilateral laparoscopic ureterolysis using hydrodissection in retroperitoneal fibrosis: a new application of an old technique

Objective: To describe our new laparoscopic approach in ureterolysis using the ERBEJET^® 2 device to hydrodissect the ureters in idiopathic retroperitoneal fibrosis.

Methods: Bilateral laparoscopic ureterolysis was done after medical therapy failure (steroids) in a 47 year old patient with retroperitoneal fibrosis. Ureteral stents were placed before surgery. Only five trocars were used for both sides, Toldt’s fascia was opened and the dissection was performed till the psoas muscle. The ureters were completely freed from the fibrotic tissue using the ERBEJET 2 device (pure hydrodissection). An omental wrap was passed behind the colonic flexure at the right and placed around the ureter. At the left, we closed Toldt’s fascia by running sutures back to the freed ureter.

Results: The operating time was 198 mins. The blood loss was 50 cc. The hospital stay was 3 days. The double J stents were removed at 4 weeks postoperatively. After 2 years, the patient is free of symptoms with normal creatinine level and no urinary tract obstructions.

Conclusions: Hydrodissection of the ureter in retroperitoneal fibrosis is a new application in the upper urinary tract laparoscopic approach that has not been described in literature before. It seems to offer excellent midterm outcomes. The use of ERBEJET 2 device seems to simplify the procedure and make it feasible and safe (less trauma to the ureter and more conservation of its blood supply). We believe that comparative studies are needed to assess the role of hydrodissection in ureterolysis for retroperitoneal fibrosis.

Effects of a Novel Piezo Actuator-driven Pulsed Water Jet System on Residual Kidney After Partial Nephrectomy in a Rat Model

OBJECTIVE

To evaluate renal damage after off-clamp partial nephrectomy (PN) using a novel surgical device, piezo actuator-driven pulsed water jet (ADPJ) system.

METHODS

Sprague-Dawley rats were divided into 4 groups and subjected to sham operation, off-clamp PN by the piezo ADPJ system, radio knife, and soft coagulation, which have been used as thermal coagulation devices. Urine and blood samples were collected, and residual kidneys were harvested at 1, 7, 14, 30, and 90 days after PN. Serum blood urea nitrogen, creatinine, and urinary and serum kidney injury molecule-1 KIM-1 levels were measured. Morphological features and the extent of renal ischemia of resection surfaces were evaluated by hematoxylin-eosin staining and immunostaining using antibodies to 1-methyladenosine, respectively. In addition, the expression levels of KIM-1 mRNA extracted from each resection surface were analyzed by quantitative real-time reverse transcription polymerase chain reaction.

RESULTS

Serum blood urea nitrogen and creatinine were significantly lower with the piezo ADPJ system than with soft coagulation. Urinary and serum KIM-1 levels were also significantly decreased with the ADPJ. The extent of 1-methyladenosine immunostaining was significantly less with the ADPJ than with thermal coagulation devices. The expression levels of KIM-1 mRNA were also lower in the ADPJ system group.

CONCLUSION

The piezo ADPJ system might attenuate renal damage after off-clamp PN.

Laparoscopic liver resection: a review of current indications and surgical techniques

Laparoscopic liver resection (LLR) has been the most impressive development in the field of liver surgery in recent two decades. Technical innovations and experience accumulation have made LLR a safe and effective procedure with faster postoperative recovery. Despite the fast spreading of the procedure, details regarding the indications, oncological outcomes and technical essentials were still disputable. To address these issues, two international consensus conferences were hold to update the knowledge in this field. The statements of the both conferences were not conclusive and more high-quality researches are required. In this article, we reviewed the development and the current state of LLR. Indications, outcomes, surgical techniques and devices used in LLR were also discussed.

Application of actuator-driven pulsed water jet for coronary artery bypass grafting: assessment in a swine model

Actuator-driven pulsed water-jet (ADPJ) dissection is an emerging surgical method for dissecting tissue without heat and mechanical injury to vessels. We elucidated the mechanical properties of the piezo ADPJ and evaluated its usefulness and safety in coronary artery bypass grafting procedures. The relationship between the input voltage (10-100 V) and peak pressure of the pulsed water jet was evaluated. The tissue strengths of swine internal thoracic and coronary arteries and the surrounding tissues were measured to assure tissue-selective dissection. Internal thoracic arteries were harvested by conventional electric cautery and the water jet in four swine, and eight coronary arteries surrounded by myocardium were attempted to be exposed with the water jet. The dissected specimens were histologically evaluated. The peak pressure of the pulsed water jet was positively correlated with the input voltage (R ² = 0.9984, P < 0.001). The breaking strengths of the target vessels (internal thoracic and coronary arteries) and the surrounding tissues were significantly different (P = 0.002 and P < 0.001, respectively). Histologic examination revealed that internal thoracic arteries were isolated with less heat damage using the pulsed water jet (P = 0.002) compared with electric cautery, and coronary arteries also were dissected without apparent histologic damage. ADPJ has the possibility of assuring tissue selectivity among the internal thoracic and coronary arteries. The results also indicated that the use of ADPJ may enhance safe procedures to harvest grafts during coronary artery bypass grafting.

The Piezo Actuator-Driven Pulsed Water Jet System for Minimizing Renal Damage after Off-Clamp Laparoscopic Partial Nephrectomy

In the setting of partial nephrectomy (PN) for renal cell carcinoma, postoperative renal dysfunction might be caused by surgical procedure. The aim of this study was to clarify the technical safety and renal damage after off-clamp laparoscopic PN (LPN) with a piezo actuator-driven pulsed water jet (ADPJ) system. Eight swine underwent off-clamp LPN with this surgical device, while off-clamp open PN was also performed with radio knife or soft coagulation. The length of the removed kidney was 40 mm, and the renal parenchyma was dissected until the renal calyx became clearly visible. The degree of renal degeneration from the resection surface was compared by Hematoxylin-Eosin staining and immunostaining for 1-methyladenosine, a sensitive marker for the ischemic tissue damage. The mRNA levels of neutrophil gelatinase-associated lipocalin (Ngal), a biomarker for acute kidney injury, were measured by quantitative real-time PCR. Off-clamp LPN with ADPJ system was successfully performed while preserving fine blood vessels and the renal calix with little bleeding. In contrast to other devices, the resection surface obtained with the ADPJ system showed only marginal degree of ischemic changes. Indeed, the expression level of Ngal mRNA was lower in the resection surface obtained with the ADPJ system than that with soft coagulation (p = 0.02). Furthermore, using the excised specimens of renal cell carcinoma, we measured the breaking strength at each site of the human kidney, suggesting the applicability of this ADPJ to clinical trials. In conclusion, off-clamp LPN with the ADPJ system could be safely performed with attenuated renal damage.

Robotic guided waterjet cutting technique for high tibial dome osteotomy: A pilot study

BACKGROUND

Oscillating saws generate high levels of heat (up to 150°C), which can lead to tissue necrosis, delayed healing and infection. Abrasive waterjet-cutting techniques have been described as a new tool to perform bone cuts, with less heat generation.

METHODS

Four lower-limbs of four human alcohol conserved cadavers were tested. Navigation references were attached to the tibia and an intraoperative fluoroscopy-based 3D scan was obtained. A 1.2 mm diameter nozzle was attached to a robotic arm, which was guided to follow a pre-specified path. In addition, a self-designed jet-absorber was applied to protect the posterior neurovascular structures. Magnesium was added as an abrasive substance to improve the cutting ability of the waterjet.

RESULTS

In all four cadavers, the osteotomies could be carried out as planned, resulting in smooth cut surfaces. No damage to the soft-tissues was observed.

CONCLUSIONS

The advantages of abrasive waterjet-cutting give it great potential in orthopaedic surgery. A current disadvantage is the amount of magnesium solute that is left on the surgical field and can be harmful to the patient.

Colliding jets provide depth control for water jetting in bone tissue

In orthopaedic surgery, water jet drilling provides several advantages over classic drilling with rigid drilling bits, such as the always sharp cut, absence of thermal damage and increased manoeuvrability. Previous research showed that the heterogeneity of bone tissue can cause variation in drilling depth whilst water jet drilling. To improve control over the drilling depth, a new method is tested consisting of two water jets that collide directly below the bone surface. The expected working principle is that after collision the jets will disintegrate, with the result of eliminating the destructive power of the coherent jets and leaving the bone tissue underneath the focal point intact. To assess the working principle of colliding water jets (CWJ), the influence of inhomogeneity of the bone tissue on the variation of the drilling depth and the impact of jet time (t_wj) on the drilling depth were compared to a single water jet (SWJ) with a similar power. 98 holes were drilled in 14 submerged porcine tali with two conditions CWJ (impact angle of 30° and 90°) and SWJ. The water pressure was 70MPa for all conditions. The water jet diameter was 0.3 mm for CWJ and 0.4 mm for SWJ. t_wj was set at 1, 3, 5 and 8s. Drilling depth and hole diameter were measured using microCT scans. A non-parametric Levene's test was performed to assess a significant difference in variance between conditions SWJ and CWJ. A regression analysis was used to determine differences in influence of t_wj on the drilling depth. Hole diameter differences were assessed using a one way Anova. A significance level of p<0.05 was set. Condition CWJ significantly decreases the drilling depth variance caused by the heterogeneity of the bone when compared to SWJ. The mean depth for CWJ was 0.9 mm (SD 0.3 mm) versus 4.8 mm (SD 2.0) for SWJ. t_wj affects the drilling depth less for condition CWJ (p<0.01, R²=0.30) than for SWJ (p<0.01, R²=0.46). The impact angle (30° or 90°) of the CWJ does not influence the drilling depth nor the variation in depth. The diameters of the resulting holes in the direction of the jets is significantly larger for CWJ at 90° than for 30° or a single jet. This study shows that CWJ provides accurate depth control when water jet drilling in an inhomogeneous material such as bone. The maximum variance measured by using the 95% confidence interval is 0.6 mm opposed to 5.4 mm for SWJ. This variance is smaller than the accuracy required for bone debridement treatments (2-4 mm deep) or drilling pilot holes. This confirms that the use of CWJ is an inherently safe method that can be used to accurately drill in bones.

Impact of monopolar radiofrequency coagulation on intraoperative blood loss during liver resection: a prospective randomised controlled trial

PURPOSE

To evaluate the impact of using monopolar thermal coagulation based on radiofrequency (RF) currents on intraoperative blood loss during liver resection.

MATERIALS AND METHODS

A prospective randomised controlled trial was planned. Patients undergoing hepatectomy were randomised into two groups. In the control group (n = 10), hemostasis was obtained with a combination of stitches, vessel-sealing bipolar RF systems, sutures or clips. In the monopolar radiofrequency coagulation (MRFC) group (n = 18), hemostasis was mainly obtained using an internally cooled monopolar RF electrode.

RESULTS

No differences in demographic or clinical characteristics were found between groups. Mean blood loss during liver resection in the control group was more than twice that of the MRFC group (556 ± 471 ml vs. 225 ± 313 ml, p = .02). The adjusted mean bleeding/transection area was also significantly higher in the control group (7.0 ± 3.3 ml/cm² vs. 2.8 ± 4.0 ml/cm², p = .006). No significant differences were observed in the rate of complications between the groups.

CONCLUSIONS

The findings suggest that the monopolar electrocoagulation created with an internally cooled RF electrode considerably reduces intraoperative blood loss during liver resection.

Liver resections can be performed safely without Pringle maneuver: A prospective study

AIM

To evaluate liver resections without Pringle maneuver, i.e., clamping of the portal triad.

METHODS

Between 9/2002 and 7/2013, 175 consecutive liver resections (n = 101 major anatomical and n = 74 large atypical > 5 cm) without Pringle maneuver were performed in 127 patients (143 surgeries). Accompanying, 37 wedge resections (specimens < 5 cm) and 43 radiofrequency ablations were performed. Preoperative volumetric calculation of the liver remnant preceeded all anatomical resections. The liver parenchyma was dissected by water-jet. The median central venous pressure was 4 mmHg (range: 5-14). Data was collected prospectively.

RESULTS

The median age of patients was 60 years (range: 16-85). Preoperative chemotherapy was used in 70 cases (49.0%). Liver cirrhosis was present in 6.3%, and liver steatosis of ≥ 10% in 28.0%. Blood loss was median 400 mL (range 50-5000 mL). Perioperative blood transfusions were given in 22/143 procedures (15%). The median weight of anatomically resected liver specimens was 525 g (range: 51-1850 g). One patient died postoperatively. Biliary leakages (n = 5) were treated conservatively. Temporary liver failure occurred in two patients.

CONCLUSION

Major liver resections without Pringle maneuver are feasible and safe. The avoidance of liver inflow clamping might reduce liver damage and failure, and shorten the hospital stay.

Extending the Capability of Using a Waterjet in Surgical Interventions by the Use of Robotics

In waterjet surgery, a thin high-pressure jet is used for dissections and surface abrasion of soft tissue. This selective preparation method preserves nerves and vessels, whereas the surrounding soft tissue is washed away.

OBJECTIVE

The aim of this study is to enhance the application field of this technique by resolving technological limitations.

METHODS

A technical task definition of handling a hand-guided waterjet applicator is derived from the literature. All reported procedures require to follow a trajectory superimposed with an oscillating movement. By introducing a robotic system and a specialized kinematic approach, the limited dexterity of the waterjet applicator is increased. Additionally, the system provides assistance by automatically performing parts of the task.

RESULTS

The method is applied to two different procedures: a minimally invasive dissection and a surface abrasion for open medical treatments. On the basis of experiments with gelatine phantoms, the performance of the method is shown for both procedures.

CONCLUSION

In the minimally invasive use case, the reachability limited by the conventional manual tools is extended by the capabilities of the robotic system. Simultaneously, the handling is simplified by automation of the superimposed oscillation. In the surface abrasion case, a dense coverage of the treated area is achievable. The risk of cross infections could be reduced by spatial separation of patient and staff.

SIGNIFICANCE

Thus, the waterjet technology can be fully integrated into robotic surgery systems and benefit from their inherent abilities.

Liver surgery in cirrhosis and portal hypertension

The prevalence of hepatic cirrhosis in Europe and the United States, currently 250 patients per 100000 inhabitants, is steadily increasing. Thus, we observe a significant increase in patients with cirrhosis and portal hypertension needing liver resections for primary or metastatic lesions. However, extended liver resections in patients with underlying hepatic cirrhosis and portal hypertension still represent a medical challenge in regard to perioperative morbidity, surgical management and postoperative outcome. The Barcelona Clinic Liver Cancer classification recommends to restrict curative liver resections for hepatocellular carcinoma in cirrhotic patients to early tumor stages in patients with Child A cirrhosis not showing portal hypertension. However, during the last two decades, relevant improvements in preoperative diagnostic, perioperative hepatologic and intensive care management as well as in surgical techniques during hepatic resections have rendered even extended liver resections in higher-degree cirrhotic patients with portal hypertension possible. However, there are few standard indications for hepatic resections in cirrhotic patients and risk stratifications have to be performed in an interdisciplinary setting for each individual patient. We here review the indications, the preoperative risk-stratifications, the morbidity and the mortality of extended resections for primary and metastatic lesions in cirrhotic livers. Furthermore, we provide a review of literature on perioperative management in cirrhotic patients needing extrahepatic abdominal surgery and an overview of surgical options in the treatment of hepatic cirrhosis.

Use of water jet instruments in gastrointestinal endoscopy

In recent years, water jet instruments have been used in the field of gastrointestinal endoscopy, mainly in two clinical situations: Investigation and treatment under endoscopic view. Injecting water jet into the gastrointestinal lumen is helpful for maintaining a clear endoscopic view, washing away blood or mucous in the lumen or on the surface of the tip of the endoscope. This contributes to reducing time and discomfort of examination. Water jet technology is an alternative method for dissecting soft tissue; this method does not harm the small vessels or cause mechanical or thermal damage. However, its use in clinical settings has been limited to the transmucosal injection of water into the submucosal layer that elevates the mucosa to prepare for endoscopic mucosal resection or endoscopic submucosal dissection, instead of tissue dissection, which may occur because of the continuous water jet. A preclinical study has been conducted using a pulsed water jet system as an alternative method for submucosal dissection by reducing intraoperative water consumption and maintenance of dissection capability. This review introduces recent studies pertaining to using a water jet in gastrointestinal endoscopy and discusses future prospects.

Evaluation of a newly developed piezo actuator-driven pulsed water jet system for liver resection in a surviving swine animal model

Background

Preservation of the hepatic vessels while dividing the parenchyma is key to achieving safe liver resection in a timely manner. In this study, we assessed the feasibility of a newly developed, piezo actuator-driven pulsed water jet (ADPJ) for liver resection in a surviving swine model.

Methods

Ten domestic pigs underwent liver resection. Parenchymal transection and vessel skeletonization were performed using the ADPJ (group A, n = 5) or an ultrasonic aspirator (group U, n = 5). The water jet was applied at a frequency of 400 Hz and a driving voltage of 80 V. Physiological saline was supplied at a flow rate of 7 ml/min. After 7 days, the animals were killed and their short-term complications were examined and compared between the two groups.

Results

No significant complications, such as massive bleeding, occurred in either group during the surgical procedures. The transection time per transection area was significantly shorter in group A than in group U (1.5 ± 0.3 vs. 2.3 ± 0.5 min/cm², respectively, P = 0.03). Blood loss per transection area was not significantly different between groups A and U (9.3 ± 4.2 vs. 11.7 ± 2.3 ml/cm², P = 0.6). All pigs in group A survived for 7 days. No postoperative bleeding or bile leakage was observed in any animal at necropsy.

Conclusion

The present results suggested that the ADPJ reduces transection time without increasing blood loss. ADPJ is a safe and feasible device for liver parenchymal transection.

Simultaneous Laparoscopy-Assisted Resection for Colorectal Cancer and Metastases

With advancement of minimal invasive surgery, a simultaneous laparoscopy-assisted resection for colorectal cancer and metastasis has become feasible. Hence, we report three cases of simultaneous laparoscopic surgery for colorectal cancer with liver or lung metastasis. In the first case, laparoscopic right hemicolectomy and left lateral segmentectomy of liver was performed for ascending colon cancer and liver metastasis. In the second case, laparoscopic right hemicolectomy and wedge resection of right lower lung was performed for cecal cancer and lung metastasis. In the third case, laparoscopic right hemicolectomy and wedge resection of left lower lung was performed for ascending colon cancer and lung metastasis. In the first two cases, patients quickly returned to normal activity. In the third case, postoperative bleeding was observed, but spontaneously stopped. There was no postoperative mortality. Simultaneous laparoscopic surgery represents a feasible option for colorectal cancer with metastases on the other organs.

What is the best technique in parenchymal transection in laparoscopic liver resection? Comprehensive review for the clinical question on the 2nd International Consensus Conference on Laparoscopic Liver Resection

The continuing evolution of technique and devices used in laparoscopic liver resection (LLR) has allowed successful application of this minimally invasive surgery for the treatment of liver disease. However, the type of instruments by energy sources and technique used vary among each institution. We reviewed the literature to seek the best technique for parenchymal transection, which was proposed as one of the important clinical question in the 2nd International Consensus Conference on LLR held on October 2014. While publications have described transection techniques used in LLR from 1991 to June 2014, it is difficult to specify the best technique and device for laparoscopic hepatic parenchymal transection, owing to a lack of randomized trials with only a small number of comparative studies. However, it is clear that instruments should be used in combination with others based on their functions and the depth of liver resection. Most authors have reported using staplers to secure and divide major vessels. Preparation for prevention of unexpected hemorrhaging particularly in liver cirrhosis, the Pringle's maneuver and prompt technique for hemostasis should be performed. We conclude that hepatobiliary surgeons should select techniques based on their familiarity with a concrete understanding of instruments and individualize to the procedure of LLR.

Modern technical approaches in resectional hepatic surgery

Techniques in liver surgery have improved considerably during the last decades, allowing for liver resections with low morbidity and mortality. Preoperative patient selection, perioperative management, and intraoperative blood-sparing techniques are the cornerstones of modern liver surgery. Multimodal treatment of colorectal liver metastases has expanded the group of patients who are potential candidates for liver resection. Adjunctive techniques, including preoperative portal vein embolization and staged hepatectomy, have facilitated the safe performance of extensive liver resection. This article provides an overview of indications for liver resection and a systematic description of the technical approach to the most commonly performed resections.

Waterjet dissection for partial nephrectomy without hilar clamping in a porcine model

Hilar clamping is typically used in partial nephrectomy to control hemorrhage, which may damage the renal tissue under warm ischemia conditions. The purpose of this study was to evaluate waterjet technology in partial nephrectomy without renal hilar vascular control in a porcine model. Bilateral partial nephrectomy using waterjet was performed in 8 pigs (16 kidneys: 8 for wedge resections, 8 for pole resections). The operations were performed successfully in all animals. The mean dissection time was 30.6 ± 2.9 minutes for pole resections and 36.5 ± 3.5 minutes for wedge resections. The mean blood loss was 51.6 ± 11.7 mL for pole resections and 38.7 ± 9.2 mL for wedge resections. The novel waterjet technique provided precise and effective hydrodissection of the kidney, avoiding damage to the vascular structures or collecting system.

The dissection profile and mechanism of tissue-selective dissection of the piezo actuator-driven pulsed water jet as a surgical instrument: laboratory investigation using Swine liver

BACKGROUND/PURPOSE

The water jet technique dissects tissue while sparing cord-like structures such as blood vessels. The mechanism of such tissue-selective dissection has been unknown. The novel piezo actuator-driven pulsed water jet (ADPJ) system can achieve dissection with remarkably reduced water consumption compared to the conventional water jet; however, the system's characteristics and dissection capabilities on any organ have not been clarified. The purposes of this study were to characterize the physical properties of the novel ADPJ system, evaluate the dissection ability in swine organs, and reveal the mechanism of tissue-selective dissection.

METHODS

The pulsed water jet system comprised a pump chamber driven by a piezo actuator, a stainless steel tube, and a nozzle. The peak pressure of the pulsed water jet was measured through a sensing hole using a pressure sensor. The pulsed water jet technique was applied on swine liver in order to dissect tissue on a moving table using one-way linear ejection at a constant speed. The dissection depth was measured with light microscopy and evaluated histologically. The physical properties of swine liver were evaluated by breaking strength tests using tabletop universal testing instruments. The liver parenchyma was also cut with three currently available surgical devices to compare the histological findings.

RESULTS

The peak pressure of the pulsed water jet positively correlated with the input voltage (R(2) = 0.9982, p < 0.0001), and this was reflected in the dissection depth. The dissection depth negatively correlated with the breaking strength of the liver parenchyma (R(2) = 0.6694, p < 0.0001). The average breaking strengths of the liver parenchyma, hepatic veins, and Glisson's sheaths were 1.41 ± 0.45, 8.66 ± 1.70, and 29.6 ± 11.0 MPa, respectively. The breaking strength of the liver parenchyma was significantly lower than that of the hepatic veins and Glisson's sheaths. Histological staining confirmed that the liver parenchyma was selectively dissected, preserving the hepatic veins and Glisson's sheaths in contrast to what is commonly observed with electrocautery or ultrasonic instruments.

CONCLUSIONS

The dissection depth of liver tissue is well controlled by input voltage and is influenced by the moving velocity and the physical properties of the organ. We showed that the device can be used to assure liver resection with tissue selectivity due to tissue-specific physical properties. Although this study uses an excised organ, further in vivo studies are necessary. The present work demonstrates that this device may function as an alternative tool for surgery due to its good controllability of the dissection depth and ability of tissue selectivity.

Outcomes of simple saline-coupled bipolar electrocautery for hepatic resection

AIM: To evaluate the application of bipolar coagulation (BIP) in hepatectomy by comparing the efficacy of BIP alone, cavitron ultrasonic surgical aspirator (CUSA) + BIP and conventional clamp crushing (CLAMP).

METHODS: Based on our database of patient records, a total of 380 consecutive patients who underwent hepatectomy at our hospital were retrospectively studied for the efficacy of BIP alone, CUSA + BIP and CLAMP. Of all the patients, 75 received saline-coupled BIP (Group A), 53 received CUSA + BIP (Group B), and 252 received CLAMP (Group C). The pre-, mid-, and postoperative clinical manifestations were compared, and the effects of those maneuvers were evaluated.

RESULTS: There was no obvious difference among the preoperative indexes between the different groups. The operative time was longer in Groups A and B than in Group C (P < 0.001 for both). The amount of bleeding and the rate of transfusion during the operation were significantly higher in Group C than in Groups A and B (P < 0.001 for all). The incidence of postoperative complications in Group C (46.43%) was higher than that in Groups A (30.67%, P = 0.015) and B (28.30%, P = 0.016). The patients’ liver function recovery and postoperative hospital stay were not significantly different. BIP could decrease intraoperative hemorrhage and postoperative complications compared to CLAMP.

CONCLUSION: Simple saline-coupled BIP should be considered a safe and reliable technique for liver resection to decrease intraoperative hemorrhage and postoperative complications.

The Nd:YAG LIMAX® 120 high-output laser: local effects and resection capacity on liver parenchyma

Various technical options are available for the resection of liver metastases, including CUSA, Ultracision, water-jet, and stapler devices. It has been shown that new generation high-output lasers are suitable for the resection of lung metastases. The goal of the present study was to evaluate the local effects of laser application on liver parenchyma. Livers of freshly slaughtered pigs (N = 6) were analyzed. The handheld laser was vertically held in the clamp of a hydraulic machine and sharply focused on the liver surface. The diode pumped Nd:YAG laser LIMAX® 120 (Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) moved evenly over the liver surface at speeds of 5, 10, and 20 mm/s. Laser outputs of 60 and 120 W were applied at every speed. Histological sections (hematoxylin and eosin (HE) staining) of the extension area of vaporization and coagulation were analyzed by the use of the ImageJ software. In addition, the area of the liver parenchyma cut by the laser within 1 min was measured. The vaporized zone appeared wedge-shaped after histological section, whereas the area of coagulation appeared radiated outward. At 10 mm/s and 60 W, the mean vaporization of the measured zone was 356.6 ± 3.9 μm in length. Superficial coagulation was observed at 20 mm/s laser speed, without effective resection. At 120 W and 5 mm/s working speed, the mean vaporization zone and the average width of coagulation were largest with 664.6 ± 5.9 and 375.6 ± 2.3 μm, respectively. The laser output power of 120 W allowed resection of an area of 6 ± 0.4 cm(2) of liver parenchyma within 1 min. The Nd:YAG Laser LIMAX® 120 might be an effective tool for liver parenchyma dissection when it is applied at maximum output (120 W) and at a constant working speed of 5 mm/s.

Perioperative outcomes of laparoscopic and robot-assisted major hepatectomies: an Italian multi-institutional comparative study

BACKGROUND

Laparoscopic major hepatectomy (LMH), although safely feasible in experienced hands and in selected patients, is a formidable challenge because of the technical demands of controlling hemorrhage, sealing bile ducts, avoiding gas embolism, and maintaining oncologic surgical principles. The enhanced surgical dexterity offered by robotic assistance could improve feasibility and/or safety of minimally invasive major hepatectomy. The aim of this study was to compare perioperative outcomes of LMH and robotic-assisted major hepatectomy (RMH).

METHODS

Pooled data from four Italian hepatobiliary centers were analyzed retrospectively. Demographic data, operative, and postoperative outcomes were collected from prospectively maintained databases and compared.

RESULTS

Between January 2009 and December 2012, 25 patients underwent LMH and 25 RMH. The two groups were comparable for all baseline characteristics including type of resection and underlying pathology. Conversion to open surgery was required in one patient in each group (4%). No difference was noted in operative time, estimated blood, and need for allogenic blood transfusions. Intermittent pedicle occlusion was required only in LMH (32% vs. 0; p = 0.004). Length of hospital stay, including time spent in intensive care unit, was similar between the two groups, but patients undergoing LMH showed quicker recovery of bowel activity, with shorter time to first flatus (1 vs. 3 days; p = 0.023) and earlier tolerance to oral liquid diet (1 vs. 2 days; p = 0.001). No difference was noted in complication rate, 90-day mortality, and readmission rate.

CONCLUSIONS

This retrospective multi-institution study confirms that selected patients can safely undergo minimally invasive major hepatectomy, either LMH or RMH. The fact that intermittent pedicle occlusion could be avoided in RMH suggests improved surgical ability to deal with bleeding during liver transection, but further studies are needed before any final conclusion can be drawn.

A novel liver parenchyma transection technique using locking straight rigid ties. An experimental study in pigs

INTRODUCTION

Technological advances have led to the development of many devices used in liver resections. However, no single transection tool is uniformly considered to be better than the others. This study aimed to develop an effective, fast, and cost-efficient technique for hepatic parenchymal transection.

MATERIALS AND METHODS

A liver parenchyma compression device in the form of a locking straight rigid tie (LoStRiT) was newly developed. Twelve pigs were distributed into two groups. The control group ( n = 6) comprised animals that underwent hepatectomy using the standard Kelly-clysis technique. The study group (n = 6) comprised animals that underwent hepatectomy using sequential LoStRiT mechanisms. The transection speed, blood loss, and biloma formation were recorded.

RESULTS

The mean parenchymal transection speed was 1.27 ± 0.27 cm(2)/min for the control group and 2.39 ± 0.56 cm(2)/min for the LoStRiT group ( p = .003). The mean blood loss per kilogram of body weight was 9.8 ± 5.2 ml/kg for the control group and 3.9 ± 0.9 ml/kg for the LoStRiT group ( p = .040). No bilomas were identified.

CONCLUSION

LoStRiT hepatectomy appears to be effective, fast, and reproducible in a porcine model of liver resection. Further development of this novel and potentially cost-efficient technique includes construction of the device using absorbable materials.

Comparative analysis of different transection techniques in minor and major hepatic resections: a prospective cohort study

BACKGROUND

In liver surgery different transection techniques are available without clear evidence regarding indication and advantage for each technique. The aim of this study was to identify the most superior liver transection technique between the different techniques (stapler, water-jet and electrocautery). Comparative analyses were performed for minor and major hepatectomies.

METHODS

In a single-center study, all liver resections performed between July 2007 and July 2012 were prospectively recorded and analysed.

RESULTS

366 liver resections were included according to predefined eligibility criteria. No clear benefit for one particular technique in minor or major hepatectomy could be shown. Cost-effectiveness analysis revealed disadvantages for stapler-hepatectomies. However, minor hepatectomies were performed with significantly lower morbidity (p < 0.001), lower operating time (p = 0.001), fewer need of transfusion (p < 0.0001) and shorter ICU stay (p = 0.001) than major hepatectomies.

CONCLUSIONS

If possible, minor hepatectomies should be chosen. Competing techniques, selected according to surgeon's preference, revealed no significant differences in primary outcome measures.

Experimental application of pulsed laser-induced water jet for endoscopic submucosal dissection: mechanical investigation and preliminary experiment in swine

BACKGROUND AND AIM

A current drawback of endoscopic submucosal dissection (ESD) for early-stage gastrointestinal tumors is the lack of instruments that can safely assist with this procedure. We have developed a pulsed jet device that can be incorporated into a gastrointestinal endoscope. Here, we investigated the mechanical profile of the pulsed jet device and demonstrated the usefulness of this instrument in esophageal ESD in swine.

METHODS

The device comprises a 5-Fr catheter, a 14-mm long stainless steel tube for generating the pulsed water jet, a nozzle and an optical quartz fiber. The pulsed water jet was generated at pulse rates of 3 Hz by irradiating the physiological saline (4°C) within the stainless steel tube with an holmium-doped yttrium-aluminum-garnet (Ho:YAG) laser at 1.1 J/pulse. Mechanical characteristics were evaluated using a force meter. The device was used only for the part of submucosal dissection in the swine ESD model. Tissues removed using the pulsed jet device and a conventional electrocautery device, and the esophagus, were histologically examined to assess thermal damage.

RESULTS

The peak impact force was observed at a stand-off distance of 40 mm (1.1 J/pulse). ESD using the pulsed jet device was successful, as the tissue specimens showed precise dissection of the submucosal layer. The extent of thermal injury was significantly lower in the dissected bed using the pulsed jet device.

CONCLUSION

The results showed that the present endoscopic pulsed jet system is a useful alternative for a safe ESD with minimum tissue injury.

Focal hydrothermal ablation: preliminary investigation of a new concept

PURPOSE

To determine whether focal tissue ablation is possible with interstitial instillation of steam.

METHODS

Fresh swine livers were used. Through a 20 gauge needle, steam was instilled every 5 s, 3 (n = 5), 6 (n = 5), 9 (n = 5), or 12 (n = 5 + 5) times in a liver lobe. The ablated zones were sectioned parallel (n = 20) or perpendicular (n = 5) to the needle track. The longitudinal long and short axis diameters, or transverse long and short axis diameters of areas with discoloration on macroscopic examination, were measured. The experiment was repeated in vivo on a pig. Steam instillation was performed once every 5 s for 5 min in the liver (n = 3) and in muscle (n = 4), and temperature changes at three neighboring sites were monitored. Long and short axis diameters of the discolored areas were measured.

RESULTS

A well-defined area of discoloration was invariably present at the site of steam instillation. The median longitudinal long axis diameter were 2.0, 2.5, 2.5, and 3.5 cm for 3, 6, 9, and 12 steam instillations in vitro, while median short axis diameters were 1.0, 1.5, 1.5, and 1.5 cm, respectively. Six attempts at ablation in vivo could be successfully completed. The long axis diameters of the ablated zones in the liver were 7.0 and 8.0 cm, while in muscle it ranged from 5.5 to 7.0 cm.

CONCLUSION

Instillation of steam in the liver in vitro and in vivo, and in muscle in vivo rapidly leads to circumscribed zones of coagulation necrosis.

Bleeding in Hepatic Surgery: Sorting through Methods to Prevent It

Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. The parameter “Blood Loss” has a central role in liver surgery, and different strategies to minimize it are a key to improve results. Moreover, recently, new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this paper is to review the different principal solutions to the problem of blood loss in hepatic surgery, focusing on technical aspects of new devices.

Techniques of hepatic resection

Liver resections are high risk procedures performed by experienced surgeons. The role of liver resection in malignant disease has changed over the last 100 years with great improvement in morbidity, mortality and long term survival. New understanding in liver anatomy, improved perioperative care, anesthesia techniques, and technological advances has improved this aspect of patient care. With improved techniques, patients previously considered unresectable have an opportunity to undergo curative surgery. This review article describes the various approaches and techniques for liver resection. The relevant anatomy and terminology of hepatic resections is discussed, as well as the role of anatomic vs. nonanatomic resection. Methods of vascular control are examined and the multiple strategies of parenchymal transection are compared, as well as minimally-invasive techniques. Finally, a brief review of the authors' practice in terms of surgical technique is offered.

Tissue damage with different surgical techniques in a porcine model of liver resection: implications for living-donor liver transplantation?

Background/purpose

For living-donor liver transplantation (LDLT) it is of paramount importance to preserve as much viable liver tissue as possible to avoid postoperative complications in the donor and recipient. The depth of tissue damage caused by common surgical techniques for liver resection has not been studied so far.

Methods

Here we compared the depth of tissue damage and the immunohistochemical expression of heat shock protein (HSP) 70, a marker for tissue damage, in a porcine model of liver resection, to assess the effect of different surgical techniques, i.e., blunt dissection (BD), and dissection with an ultrasound aspirator (UA), an ultrasound scalpel (US), or a water-jet (WJ).

Results

Analysis with linear mixed effects models (LME) showed significantly less tissue damage with BD and UA than with US and WJ (joint p value <0.001). Damage also increased within 6 h after surgery (p value = 0.004). Semiquantitative evaluation of HSP 70 showed increased expression after resection with US compared to all other resection methods (p value <0.001), indicating increased tissue damage with this method.

Conclusion

We suggest that in cases of liver resection for LDLT surgeons should reevaluate using US and WJ because of possible excessive tissue damage compared to BD and UA. Overall we advocate the use of BD as it requires no special equipment and, hence, has considerably higher cost-effectiveness without compromising tissue preservation and clinical outcome and is readily available even in low-tech environments.

Waterjet dissection of peripheral nerves: an experimental study of the sciatic nerve of rats

BACKGROUND

Although waterjet dissection has been well evaluated in intracranial pathologies, little is known of its qualities in peripheral nerve surgery. Theoretically, the precise dissection qualities could support the separation of nerves from adjacent tissues and improve the preservation of nerve integrity in peripheral nerve surgery.

OBJECTIVE

To evaluate the potential of the new waterjet dissector in peripheral nerve surgery.

METHODS

Waterjet dissection with pressures of 20 to 80 bar was applied on the sciatic nerves of 101 rats. The effect of waterjet dissection on the sciatic nerve was evaluated by clinical tests, neurophysiological examinations, and histopathological studies up to 12 weeks after surgery.

RESULTS

With waterjet pressures up to 30 bar, the sciatic nerve was preserved in its integrity in all cases. Functional damaging was observed at pressures of 40 bar and higher. However, all but 1 rat in the 80 bar subgroup showed complete functional regeneration at 12 weeks after surgery. Histopathologically, small water bubbles were observed around the nerves. At 40 bar and higher, the sciatic nerves showed signs of direct nerve injury. However, all these animals showed nerve regeneration after 12 weeks, as demonstrated by histological studies.

CONCLUSION

Sciatic nerves were preserved functionally and morphologically at pressures up to 30 bar. Between 40 and 80 bar, reliable functional and morphological nerve regeneration occurred. Waterjet pressures up to 30 bar might be applied safely under clinical conditions. This technique might be well suited to separate intact peripheral nerves from adjacent tumor or scar tissue. Further studies will have to show the clinical relevance of these dissection qualities.

Water jet dissection in neurosurgery: an update after 208 procedures with special reference to surgical technique and complications

BACKGROUND

Water jet dissection represents a promising technique for precise brain tissue dissection with preservation of blood vessels. In the past, the water jet dissector has been used for various pathologies. A detailed report of the surgical technique is lacking.

OBJECTIVE

The authors present their results after 208 procedures with a special focus on surgical technique, intraoperative suitability, advantages, and disadvantages.

METHODS

Between March 1997 and April 2009, 208 patients with various intracranial neurosurgical pathologies were operated on with the water jet dissector. Handling of the device and its usefulness and extent of application were assessed. The pressures encountered, potential risks, and complications were documented. The patients were followed 1 to 24 months postoperatively.

RESULTS

A detailed presentation of the surgical technique is given. Differences and limitations of the water jet dissection device in the various pathologies were evaluated. The water jet dissector was intensively used in 127 procedures (61.1%), intermittently used in 56 procedures (26.9%), and scarcely used in 25 procedures (12%). The device was considered to be very helpful in 166 procedures (79.8%) and helpful to some extent in 33 procedures (15.9%). In 8 (3.8%) procedures, it was not helpful, and in 1 procedure (0.5%), the usefulness was not documented by the surgeon.

CONCLUSION

The water jet dissector can be applied easily and very safely. Precise tissue dissection with preservation of blood vessels and no greater risk of complications are possible. However, the clinical consequences of the described qualities need to be demonstrated in a randomized clinical trial.