Use of water jet resection in organ-sparing kidney surgery

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n > 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.

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.

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.

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.

Energy sources for laparoscopic partial nephrectomy--critical appraisal

Laparoscopic partial nephrectomy (LPN) has emerged as a viable alternative for the conventional open nephron-sparing surgery (NSS). So far, an adequate renal parenchymal cutting and hemostasis, as well as caliceal repair remains technically challenging. Numerous investigators have developed techniques using different energy sources to simplify the technically demanding LPN. Herein we review these energy sources, discussing perceived advantages and disadvantages of each technique.

Hydro-Jet technology in urologic surgery

Hydro-Jet technology utilizes an extremely thin, high-pressure stream of water. This technology has been routinely used in industry as a cutting tool for different materials such as metal, ceramic, wood and glass. Recently, Hydro-Jet technology has been used for dissection and resection during open and laparoscopic surgical procedures. A high-pressure jet of water allows selective dissection and isolation of vital structures such as blood vessels and nerves. This has resulted in improved dissection and decreased complication rate in recent experimental and clinical studies. This technology has been successfully applied during open and laparoscopic partial nephrectomy, cholecystecomy and retroperitoneal lymphadenectomy.

Water dissection technique of Toth for opening neurosurgical cleavage planes

BACKGROUND

The low-pressure water dissection technique of Toth, first reported in 1987, is a method to cautiously open neurosurgical cleavage planes such as the sylvian fissure or the interhemispheric space, and the interfaces between extraparenchymal masses and the adjacent brain. The aim of this technical report is to present our long-term experience with this simple and elegant asset of microneurosurgery and to promote its widespread use.

METHOD

Water is injected under microscopic control by a hand-held syringe with a blunt needle or by an irrigating balloon applying repeated injections of physiological saline into the cleavage plane to open it.

FINDINGS AND CONCLUSION

The water dissection technique of Toth has been extensively used in Budapest and Helsinki in thousands of microsurgical cases, in removal of meningiomas and to open sylvian and interhemispheric fissure. In our experience, there have been no noticeable complications, and we recommend this technique for widespread use. It is a very inexpensive, simple, and effective method not requiring any expensive or complicated devices.

Kidney transplantation in the rat: A modified technique using hydrodissection

Here, hydrodissection was compared with the conventional blunt instrumental dissection approach in a rat model of orthotopic kidney transplantation. Forty male Fisher and Lewis rats were used as kidney donors and recipients, respectively. After recipient nephrectomy, left kidney grafts were implanted orthotopically using standard microsurgical techniques. Two different methods of dissection of the graft and recipient vessels were used. In method A, the dissection was performed using blunt dissection with cotton-tipped sticks and jeweler's forceps (n = 20), and in method B, dissection was performed using water dissection technique (n = 20). Hydrodissection displayed the correct plane of dissection, reduced the operating time, and reduced the overall complication (P < 0.001) and vasospasm (P < 0.05) rates. This is the first report of the use of hydrodissection in experimental transplantation. This atraumatic dissection technique does not require any special instruments, is fast, safe, demands less surgical skills, and may be useful in other transplantation models.

Laparoscopic partial nephrectomy

BACKGROUND AND PURPOSE

The technique of laparoscopic partial nephrectomy has matured significantly over the past decade and is emerging as an oncologically sound procedure for the management of small renal tumors. Methods of tumor excision as well as parenchymal reconstruction in a hemostatically controlled field have evolved to make this procedure safer. Improved techniques to minimize warm renal ischemia are being developed. Finally, methods to prevent positive surgical margins during laparoscopic surgery are crucial to a satisfactory oncologic outcome. These important technical issues, as well as the current results of laparoscopic partial nephrectomy, are discussed.

MATERIALS AND METHODS

The urologic peer-review literature related to nephron-sparing surgery was reviewed. Controversial issues with respect to the surgical approach, methods of hemostatic control, acceptable time of warm ischemia, and cooling techniques were reviewed and collated. Perioperative results from larger series of laparoscopic and open partial nephrectomy were evaluated.

RESULTS

Open nephron-sparing surgery for renal tumors < or =4 cm has cancer control equivalent to that of open radical nephrectomy. Evidence is now emerging that laparoscopic partial nephrectomy will provide similar oncologic results, although clinical follow-up is still early. Blood loss, postoperative pain, and convalescence seem to be favor the laparoscopic approach. Complication rates, primarily postoperative bleeding and urine leak, may be higher than for open nephron-sparing surgery. Methods of laparoscopic hemostatic control favor soft vascular clamping for larger tumors that are more endophytic and central. Smaller exophytic lesions may be managed without renal vascular control using a variety of coagulative and hemostatic tools. Data related to warm renal ischemia suggest that the time used for tumor excision and renal reconstruction should be 30 minutes or less. Techniques for laparoscopic renal cooling are being developed.

CONCLUSIONS

Laparoscopic nephron-sparing surgery is a technique in evolution but with a promising outlook. The urologic peer-review literature reflects an exponential growth in interest, which suggests that this minimally invasive approach is practical and may benefit our patient population so as to allow them to return to normal healthy living more quickly.

Laparoscopic Retroperitoneal Lymph-Node Dissection with the Waterjet Is Technically Feasible and Safe in Testis-Cancer Patient

BACKGROUND AND PURPOSE

The acceptance of open retroperitoneal lymph node dissection (RPLND) for stage I and II nonseminomatous testicular cancer has decreased because of the intraoperative and postoperative morbidity of the procedure. Laparoscopic RPLND is a minimally invasive and safe alternative for low-stage germ-cell tumors. It is, however, technically demanding and should therefore be performed only in experienced centers. The purpose of the present study was to evaluate the waterjet technique for laparoscopic RPLND.

PATIENTS AND METHODS

A series of 18 patients with clinical stage I testis cancer (group A) and 7 patients who had received chemotherapy for stage II disease (group B) underwent laparoscopic RPLND at our institution. The procedure was performed identically to the open approach using the modified template according to Weissbach and associates. The waterjet was used for removal of lymphatic tissue from the aorta and the vena cava, as well as from the sympathetic trunk.

RESULTS

The operation was completed in all patients without conversion to open surgery. The mean operating time was 232 +/- 48 minutes. The waterjet was able to remove lymphatic tissue easily and atraumatically. At pressures of 20 bar, the lymph-node capsule remained completely intact, thus avoiding tumor-cell spread. Antegrade ejaculation could be preserved in all patients, who, to date, show no evidence of disease.

CONCLUSIONS

The waterjet allows the safe and complete removal of lymphatic tissue, leaving vulnerable anatomic structures intact. It can decrease the learning curve of laparoscopic RPLND and contribute to better acceptance of this procedure.

Water jet assisted laparoscopic partial nephrectomy without hilar clamping in the calf model

PURPOSE

Hemostasis represents a primary challenge during laparoscopic partial nephrectomy (LPN). We typically clamp the renal artery/vein en bloc and perform LPN expeditiously under warm ischemia conditions. We evaluated Helix Hydro-jet assisted LPN without renal hilar vascular control in the survival calf model.

MATERIALS AND METHODS

Staged bilateral LPN using the Hydro-jet was performed without renal hilar vessel control in 10 survival calves (20 kidneys). Parenchymal hydrodissection was performed with a high velocity, ultracoherent saline stream at 450 psi through a small nozzle with integrated suction at the tip. The denuded intrarenal parenchymal blood vessels were precisely coagulated with a BIClamp bipolar instrument and transected. Followup involved biochemical, radiological and histopathological evaluation at designated sacrifice intervals of 1 and 2 weeks, and 1, 2 and 3 months, respectively.

RESULTS

All LPNs were completed successfully without open conversion. Of 20 LPNs 18 (90%) were performed without hilar clamping. Pelvicaliceal suture repair was necessary in 5 of 10 chronic kidneys (50%). Mean Hydro-jet(R) partial nephrectomy time was 63 minutes (range 13 to 150), mean estimated blood loss was 174 cc (range 20 to 750) and mean volume of normal saline used for hydro-dissection was 260 cc (mean 50 to 1,250). No animal had a urinary leak. Histological sections from the acute specimen revealed a thin (1 mm) layer of adherent coagulum at the amputation site with minimal thermal artifact. At 2 weeks a layer of adherent fibro-inflammatory pseudomembrane with giant cell reaction was seen.

CONCLUSIONS

In this more stringent and robust survival calf model Hydro-jet assisted LPN can be performed without hilar vessel control, thus, completely avoiding warm ischemia. This approach has the potential to decrease the level of technical difficulty inherent in LPN.

Nerve-sparing retroperitoneal lymphadenectomy using hydro-jet dissection: initial experience

BACKGROUND AND PURPOSE

Nerve-sparing retroperitoneal lymphadenectomy (RPL) is performed in a significant number of patients to preserve ejaculation after treatment for testicular cancer. Identification and preservation of the sympathetic nerves may be challenging. Hydro-Jet technology has been utilized for various surgical applications. A small high-pressure stream of water is used to delineate surgical planes, with preservation of vascular and neural structures. We have examined the utility of this technology for RPL in a porcine model and in human subjects.

MATERIALS AND METHOD

A Helix Hydro-Jet device (Erbe, USA) was used for all procedures. A high-pressure water-jet stream is directed through a small nozzle with a 120-microm inner radius for soft-tissue dissection. The upper pressure limit (range 0-2175 psi) is set using a digital monitor. The jet is initiated using a foot pedal, and the actual pressure is monitored. A pressure of 360 to 400 psi was used for experimental studies, which was decreased to 255 to 300 psi for human use. Three pigs underwent RPL using this technique. Subsequently, RPL was performed in five men with testicular cancer, being primary in two and postchemotherapy in three. The primary diagnosis was seminoma in one and non-seminomatous cancer in four. The patient with seminoma had a residual mass after chemotherapy.

RESULTS

The procedures were completed successfully in all subjects. There were no intraoperative or postoperative complications. Hydro-Jet dissection permitted tissue selectivity, with preservation of vascular structures and sympathetic nerves. The soft tissue and lymphatics were removed with the high-pressure water stream assisted by blunt dissection. The nerve fibers were grossly resistant to the pressure used and were isolated individually. Dissection around the great vessels appeared to be safe, and no injury was observed with direct application of the jet. Lumbar arteries and veins and accessory vessels could be isolated safely. The estimated blood loss was minimal in animals and 300 to 800 mL in humans.

CONCLUSIONS

Hydro-Jet dissection demonstrated tissue selectivity using a pressure range of 255 to 300 psi in humans. The vascular structures and sympathetic nerves were preserved. Our initial experience with this device for nerve-sparing RPL is encouraging.

Use of hydro-jet cutting for laparoscopic partial nephrectomy in a porcine model

OBJECTIVES

To evaluate whether a laparoscopic hydro-jet device can provide a safe and effective partial nephrectomy. Partial nephrectomy is still one of the most challenging operations in urologic laparoscopy. The control of hemorrhage is very difficult to achieve with laparoscopic techniques. In open surgery, hydro-jet resection is used to cut the renal parenchyma selectively, avoiding damage to the vascular structures or collecting system.Methods. Laparoscopic wedge, as well as pole, resections of the kidney were performed in 5 pigs under general anesthesia. After exposure of the kidney, the renal capsule was incised using electrocautery. The hydro-jet was then used to dissect the renal parenchyma. In pole resections, the collecting system and central vessels were divided using an Endo-GIA. Hemostasis was achieved by electrocoagulation or clips. The dissection time and intraoperative complications were evaluated.Results. The operations were performed successfully in all animals without temporary ischemia. The hydro-jet generator allowed precise and effective tissue dissection without significant hemorrhage. The parenchymal vessels were selectively coagulated. The collecting system and central vessels remained intact and could be divided after application of the Endo-GIA. The mean dissection time was 42 +/- 6 minutes for the wedge resections and 54 +/- 8 minutes for the pole resections.

CONCLUSIONS

These experimental results demonstrate the suitability of hydro-jet dissection for safe laparoscopic partial nephrectomy without temporary ischemia and with reduction of the operative trauma to the kidney. On the basis of our own experiences with other techniques, including electrocautery and laser technology for partial nephrectomy, we conclude that laparoscopic hydro-jet resection represents an interesting alternative to other techniques.