Reconstructive renal surgery using a water jet

Effect of endoscope flexibility on tissue dissection profile assessed with pulsed water jet device: ensuring safety, efficacy, and handling of thin devices for neuroendoscopic surgery

Objective

We developed an actuator-driven pulsed water jet device (ADPJ) for flexible neuroendoscopy to achieve effective tissue dissection with vasculature preservation. Although flexibility is a strong advantage for minimally invasiveness, the effect of the ductile curvature on the dissection profiles remains unknown. The purpose of this study was to clarify the impact of the curvature change of the ADPJ connecting tube on the dissection safety and efficacy.

Results

Three ADPJ connecting tubes with different inner diameters (1.0, 0.75, 0.5 mm) were used to dissect the brain phantom. They were bent at 3 angles: 0°, 60°, and 120°. The dissection profiles were evaluated using the mean depth and coefficient of variation (CV) for efficacy and safety, respectively.The larger inner diameter connecting tube dissected more deeply. The dissection depth was not changed regardless of the curvature degree in each tube. There was no significant difference in CVs regardless of inner diameter and curvature. The ductile curvature of the flexible neuroendoscope did not affect the efficacy and safety of the ADPJ dissection profile. Among the numerous instruments, tube-formed devices, including suction and injecting devices such as ADPJ, can be used safely and effectively without flexibility-related limitations.

Application of actuator-driven pulsed water jet in aneurysmal subarachnoid hemorrhage surgery: its effectiveness for dissection around ruptured aneurysmal walls and subarachnoid clot removal

In clipping surgery for aneurysmal subarachnoid hemorrhage (aSAH), critical steps include clot removal and dissection of aneurysms without premature rupture or brain injuries. To pursue this goal, a piezo actuator-driven pulsed water jet (ADPJ) system was introduced in this study. This study included 42 patients, who suffered aSAH and underwent clipping surgery. Eleven patients underwent surgery with the assistance of the ADPJ system (ADPJ group). In the other 31 patients, surgery was performed without the ADPJ system (Control group). The ADPJ system was used for clot removal and aneurysmal dissection. The clinical impact of the ADPJ system was judged by comparing the rate of premature rupture, degree of clot removal, and clinical outcomes. Intraoperatively, a premature rupture was encountered in 18.2 and 25.8% of cases in the ADPJ and control groups, respectively. Although the differences were not statistically significant, intraoperative observation suggested that the ADPJ system was effective in clot removal and dissection of aneurysms in a safe manner. Computed tomography scans indicated the achievement of higher degrees of clot removal, especially when the ADPJ system was used for cases with preoperative clot volumes of more than 25 ml (p = 0.047, Mann-Whitney U test). Clinical outcomes, including incidence of postoperative brain injury or symptomatic vasospasm, were similar in both groups. We described our preliminary surgical results using the ADPJ system for aSAH. Although further study is needed, the ADPJ system was considered a safe and effective tool for clot removal and dissection of aneurysms.

Use of Actuator-Driven Pulsed Water Jet in Brain and Spinal Cord Cavernous Malformations Resection

BACKGROUND

A piezo actuator-driven pulsed water jet (ADPJ) system is a novel surgical instrument that enables dissection of tissue without thermal damage. It can potentially resect intra-axial lesions while preserving neurological function.

OBJECTIVE

To report our first experience of applying an ADPJ system to brain and spinal cord cavernous malformations.

METHODS

Four patients (2 women and 2 men, mean age 44.5 years) with brain (n = 3) and spinal cord (n = 1) cavernous malformations were enrolled in the study. All surgeries were performed with the aid of the ADPJ system. Postoperative neurological function and radiological findings were evaluated.

RESULTS

The ADPJ system was useful in dissecting boundaries between the lesion and surrounding brain/spinal cord tissues. The pulsed water jet provided a clear surgical view and helped surgeons follow the margins. Water jet dissection peeled off the brain and spinal cord tissues from the lesion wall. Surrounding gliotic tissue was preserved. As a consequence, the cavernous malformations were successfully removed. Postoperative magnetic resonance imaging confirmed total removal of lesions in all cases. Preoperative neurological symptoms completely resolved in 2 patients. The others experienced partial recovery. No patients developed new postoperative neurological deficits; facial palsy temporarily worsened in 1 patient who underwent a suprafacial colliculus approach for the brainstem lesion.

CONCLUSION

The ADPJ provided a clear surgical field and enabled surgeons to dissect boundaries between lesions and surrounding brain and spinal cord gliotic tissue. The ADPJ system is a feasible option for cavernous malformation surgery, enabling successful tumor removal and preservation of neurological function.

Ventricle wall dissection and vascular preservation with the pulsed water jet device: novel tissue dissector for flexible neuroendoscopic surgery

OBJECTIVE

Neuroendoscopic surgery allows minimally invasive surgery, but lacks effective methods to control bleeding. Water jet dissection with continuous flow has been used in liver and kidney surgery since the 1980s, and is effective for tissue manipulation with vascular preservation, but involves some potential risks, such as elevation of intracranial pressure during application in the ventricles. The authors previously reported the efficacy of the actuator-driven pulsed water jet device (ADPJ) to dissect soft tissue with vascular preservation in microscopic neurosurgery. This feasibility study investigated the use of the ADPJ to reduce the amount of water usage, leading to more safety with sustained efficacy.

METHODS

A small-diameter pulsed water jet device was developed for use with the flexible neuroendoscope. To identify the optimal conditions for the water jet, the flow rate, water pressure, and distance between the nozzle and target were analyzed in an in vitro study by using a gelatin brain phantom. A ventricle model was used to monitor the internal pressure and temperature. For ex vivo experiments the porcine brain was harvested and ventricle walls were exposed, and subsequently immersed into physiological saline. For in vivo experiments the cortex was microsurgically resected to make the small cortico-ventricle window, and then the endoscope was introduced to dissect ventricle walls.

RESULTS

In the in vitro experiments, water pressure was approximately 6.5 bar at 0.5 mm from the ADPJ nozzle and was maintained at 1 mm, but dropped rapidly toward 50% at 2 mm, and became 10% at 3.5 mm. The ADPJ required less water to achieve the same dissection depth compared with the continuous-flow water jet. With the ventricle model, the internal pressure and temperature were well controlled at the baseline, with open water drainage. These results indicated that the ADPJ can be safely applied within the ventricles. The ADPJ was introduced into a flexible endoscope and the ventricle walls were dissected in both the ex vivo and in vivo conditions. The ventricle wall was dissected without obscuring the view, and the vascular structures were anatomically preserved under direct application. Histological examination revealed that both the vessels on the ventricle wall and the fine vessels in the parenchyma were preserved.

CONCLUSIONS

The ADPJ can safely and effectively dissect the ventricle wall, with vascular preservation in immersed conditions. To achieve the optimal result of tissue dissection with minimal surgical risk, the ADPJ is a potential device for neuroendoscopic surgery of the ventricles.

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.

First experimental results with a new waterjet dissector: Erbejet 2

BACKGROUND

Waterjet dissection represents a useful technique for many surgical procedures. In this experimental study, the technical features and dissection qualities of the new Erbejet 2 with its new pump and nozzle applicator system are evaluated for its neurosurgical use compared to the established Helix Hydro-Jet.

METHODS

One hundred twenty-six fresh cadaveric pig brains were simultaneously cut with the Helix Hydro-Jet and Erbejet 2. Different pressure levels were applied to cerebral tissue with and without meninges, cerebellum and brainstem. Additionally, dissection characteristics of various cutting media were investigated.

FINDINGS

There was a nearly equal dissection quality at up to 10 bar of both instruments. In contrast to the Helix Hydro-Jet, Erbejet 2 application at higher pressures resulted in an almost linear increase of dissection depth with a small standard deviation. Smoother cutting margins and less foaming were found. Preserved vessels were observed with both devices. Hydroxyaethyl starch led, in contrast to Ringer's solution and isotonic saline solution, to increased dissection width and more foaming.

CONCLUSIONS

The new Erbejet 2 is more precise, with almost linear correlation of pressure and dissection depth compared to the Helix Hydro-Jet. Less foaming and the possible application of various separating media are a considerable advantage. All things considered, the new Erbejet 2 offers more options to enlarge the field of neurosurgical indications for waterjet dissection.

Waterjet dissection of the vestibulocochlear nerve: an experimental study

Object

Waterjet dissection has been shown to protect intracerebral vessels, but no experience exists in applying this modality to the cranial nerves. To evaluate its potential, the authors examined waterjet dissection of the vestibulocochlear nerve in rats.

Methods

Lateral suboccipital craniectomy and microsurgical preparation of the vestibulocochlear nerve were performed in 42 rats. Water pressures of 2–10 bar were applied, and the effect was microscopically evaluated. Auditory brainstem responses (ABRs) were used to define nerve function compared with preoperative values and the healthy contralateral side. The final anatomical preparation documented the morphological and histological effects of waterjet pressure on the nerve.

Results

In using up to 6 bar, the cochlear nerve was preserved in all cases. Eight bar moderately damaged the nerve surface. A 10-bar jet markedly damaged or even completely dissected the nerve. Time course analysis of the ABR demonstrated complete functional nerve preservation up to 6 bar after 6 weeks in all rats. Waterjet dissection with 8 bar was associated with a 60% recovery of ABR. In the 10-bar group, no recovery was seen.

Conclusions

Microsurgical dissection of cranial nerves is possible using waterjet dissection while preserving both morphology and function. The aforementioned jet pressures are known to be effective in neurosurgical treatment of tumors. Thus, waterjet dissection may be useful in skull base surgery including dissection of cranial nerves from tumors. Further studies on this subject are encouraged.

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.

Waterjet dissection versus ultrasonic aspiration in epilepsy surgery

OBJECTIVE

Waterjet dissection is currently under close investigation in neurosurgery. Experimentally, precise brain parenchyma dissection with vessel preservation has been demonstrated. Clinically, the safety of the instrument has already been proved. However, precise data demonstrating that waterjet dissection indeed reduces surgical blood loss are still missing.

METHODS

The authors applied the waterjet device in a prospective randomized study in comparison with the ultrasonic aspirator. Because there is little variability in the procedure, 30 patients with temporal lobe epilepsy receiving a tailored temporal lobe resection between December 1999 and October 2002 were selected for this study. Intraoperative vessel preservation, intraoperative blood loss, surgical complications, and epilepsy outcome were evaluated. All patients were followed at 3-month intervals.

RESULTS

During surgery, both instruments were easy to handle. Only with the waterjet dissector, however, were even small intraparenchymal blood vessels preserved. Intraoperative blood loss was significantly reduced with the waterjet (mean, 70 +/- 46 ml) compared with the ultrasonic aspirator (mean, 121 +/- 48 ml). However, no difference in the necessity for blood transfusion occurred. No difference was observed with respect to operation time (238.6 +/- 37.0 min with the waterjet, 247.5 +/- 41.5 min with the ultrasonic aspirator), surgical complications, and outcome.

CONCLUSION

The waterjet dissector enables a significant reduction of intraoperative blood loss in the investigated setting. However, further studies are needed to confirm these results with a larger number of patients. Studies also are needed to prove that the reduction of blood loss is of clinical relevance for the outcome of the patients.

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.

Comparison of waterjet dissection and ultrasonic aspiration: an in vivo study in the rabbit brain

Object. The waterjet method of dissection has been shown to enable the precise dissection of the parenchyma vessels while preserving blood in cadaveric pig brains. The waterjet device has also been applied clinically to treat various diseases and disorders without complications. Evidence still remains to be gathered as to how the instrument performs in reducing surgical trauma, intraoperative blood loss, and postsurgical brain edema. In the present study the authors investigate these parameters in a comparison between waterjet dissection and ultrasonic aspiration in the rabbit brain in vivo.

Methods. Thirty-one rabbits received identical bilateral frontal corticotomies, which were created using the waterjet device or an ultrasonic aspirator. The animals were killed 1, 3, or 7 days, or 6 weeks after surgery and their brains were processed for immunohistological analysis. Blood vessel preservation, intraoperative hemorrhage, postsurgical brain edema, and posttraumatic microglial and astoglial reactions were evaluated. Only in animals subjected to waterjet dissection were preserved vessels observed within the corticotomies. In addition, less intraoperative bleeding occurred in animals in which the waterjet was used. The microglial reaction was significantly reduced by waterjet dissection compared with ultrasonic aspiration; however, no difference in edema formation or astrocytic reactivity was observed.

Conclusions. These results demonstrate that waterjet dissection appears to be less traumatic than ultrasonic aspiration with respect to intraoperative hemorrhage and postoperative microglial reactivity in the rabbit model. Nevertheless, no difference in edema formation could be demonstrated. It remains to be proven that the observed differences are of clinical relevance.

Waterjet dissection in the brain: review of the experimental and clinical data with special reference to meningioma surgery

Waterjet dissection enables precise parenchymal dissection under preservation of vessels and reduction of intraoperative blood loss in general surgery. The present study reports our experimental and clinical results with this device in neurosurgery. Our experimental studies in the porcine cadaver brain show that the device allows very accurate, precise, and reliable dissection of the brain. A linear relationship between waterjet pressure and dissection depth was demonstrated. Vessel preservation was observed at pressures below 20 bar. Clinically, precise dissection of brain parenchyma and various tumors was performed without complications. Even in meningiomas, with their very variable firmness, vascularization, and adherence to the surrounding brain, accurate dissection could be achieved. However, while tumor separation from the brain was attained with high accuracy and vessel preservation in all cases, only in softer lesions resection by aspiration under vessel preservation was possible with pressures below 20 bar. In all, the waterjet device enables precise tissue dissection and vessel preservation in various pathologies including meningiomas. It could represent an addition to the neurosurgical armamentarium. Further studies will have to show dissection qualities of this device that are superior to conventional methods.

Waterjet resection of brain metastases - first clinical results with 10 patients

The waterjet technique enables precise tissue dissection without thermal damage and with preservation of vessels in general surgery. In neurosurgery, these qualities could help to avoid damage of intact brain parenchyma in tumour resections. The present study reports our first results with this technique in brain metastases. Ten patients with intracranial metastases underwent surgery with the aid of the waterjet. Resection was performed in combination with conventional neurosurgical methods. The follow-up consisted of neurological examination and MRI studies. Intraoperatively, the device was easy to handle. No complications due to the device were observed. Vessels were preserved at pressures below 20 bars. Six of the tumours consisted of soft tissue which was poorly demarcated from the surrounding brain. In these tumours, the waterjet was very helpful. It enabled tumour debulking by aspiration and - more important - precise separation of tumour and brain parenchyma. The remaining four cases were rather hard and well demarcated metastases. In these only separation of the tumour from the surrounding brain was achieved. In conclusion, the waterjet can be applied in surgery of brain metastases without complications. The device appears particularly suitable for soft, poorly demarcated metastases. Further clinical studies with this device are required.

Der gepulste Wasserstrahl zur selektiven Knochenzemententfernung in der Revisionsendoprothetik. The Pulsed Water Jet for Selective Removal of Bone Cement During Revision Arthroplasty

Conventional tools used in prosthetic revision surgery have a limited range of action within the narrow cement mantle. Water jet cutting technology permits tiny and precisely controlled cuts, and may therefore be an alternative method of bone cement removal. Our study compares the cutting performance on bone cement (PMMA) and bone of a pulsed water jet and a continuous water jet. The aim of the study was to establish whether selective removal of PMMA is possible. 55 bone specimens (bovine femora) and 32 specimens of PMMA were cut with a continuous and a pulsed water jet at different pressures (40 MPa, 60 MPa) and pulse frequencies (0Hz, 50Hz, 250Hz). To ensure comparability of the results, the depths of cut were related to the hydraulic power of that part of the jet actually impinging on the material. While for PMMA the power-related depth of cut increased significantly with the pulse frequency, this did not apply to bone. The cuts produced in bone were sharp-edged. Since PMMA is more brittle than bone, the water jet caused cracks that enlarged further until particles of bone broke away. Although selective removal of PMMA without doing damage to the bone was not possible at the investigated settings of the jet parameters, the results do show that a pulsed water jet can cut bone cement much more effectively than bone. This is an important advantage over conventional non-selective tools for the removal of bone cement.

Water jet dissection in neurosurgery: experimental results in the porcine cadaveric brain

OBJECTIVE

Water jet dissection is currently under investigation as a new tool for use in neurosurgical procedures. The safety of this instrument has already been demonstrated. However, precise data demonstrating highly accurate tissue dissection in the brain in combination with vessel preservation are still missing.

METHODS

In this study, 50 porcine cadaveric brains were dissected with the use of several nozzle types (80-150 in microm diameter, coherent straight or helically turned jet) and several levels of water jet pressure (1-40 bars). The dissection characteristics in various brain regions and the basilar artery were evaluated morphologically.

RESULTS

The best results regarding reliable function, dissection accuracy, and the correlation of water jet pressure with dissection depth were obtained with the 120-microm Helix Hydro-Jet nozzle. An almost linear relationship of pressure increase with dissection depth was demonstrated. The dissection depth varied significantly up to threefold, depending on the area investigated (greatest resistance was in the brainstem, followed by hemispheres and then the cerebellum). Vessels including the basilar artery resisted pressure up to 15 bars in most cases, whereas the basilar artery was dissected significantly more often with higher pressure.

CONCLUSION

The results indicate that 1) use of the water jet enables very precise and reliable brain parenchyma dissection with vessel preservation under conditions corresponding to the clinical situation, and 2) the nozzle type and water jet pressure must be selected carefully according to the brain area and tissue targeted. This study provides the morphological basis for further research with the use of the water jet technique in the brain. The water jet's characteristics may make this device a useful addition to the neurosurgical armamentarium.

Waterjet dissection in neurosurgical procedures: clinical results in 35 patients

OBJECT

Waterjet dissection represents a new minimally traumatic surgical method for dissection that can be used in various parenchymal organs, in which it allows highly precise parenchymal dissection while preserving blood vessels, resulting in reduced intraoperative blood loss. This study was performed to investigate the clinical application of this new technique in neurosurgical procedures, such as brain tumor resection and epilepsy surgery.

METHODS

Thirty-four patients with gliomas (Grades II-IV), cerebral metastases, temporal lobe epilepsy, or cerebellar hemangioblastomas, and one patient with internal carotid artery (ICA) stenosis were treated surgically with the aid of the waterjet. Resection was performed using waterjet dissection in combination with conventional neurosurgical procedures. Intraoperatively, the waterjet was easy to handle, and no complications due to the device were observed. Dissection of tissue was possible for all pathological conditions, and pressures between 3 and 45 bars were used. In gliomas, metastases, epilepsy surgery, and hemangioblastoma, the tissue was dissected at pressures between 3 and 17 bars, which preserved blood vessels. Dissection of meningiomas and the ICA stenosis required higher pressures (between 20 and 45 bars); with these pressures, blood vessels were also dissected.

CONCLUSIONS

These results indicate that the waterjet dissection procedure can be used intraoperatively without complications. This device appears to be particularly suitable for the dissection of highly vascularized gliomas or normal brain tissue, in which tissue dissection with sparing of blood vessels can be achieved. To prove that this is a useful addition to the neurosurgical armamentarium, reduction of blood loss or postoperative brain edema compared with conventional methods should be demonstrated in future studies.

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.

Use of water jet resection in organ-sparing kidney surgery

BACKGROUND AND PURPOSE

The morbidity of organ-sparing renal surgery is related to intraoperative hemorrhaging and secondarily to urinary fistulae and urinoma. Various tools have been developed for gentle transection and precise control of bleeding. Water jet technology is already established in clinical practice for surgery of the liver and other parenchymatous organs. We report our clinical experience with a new water jet resection device in kidney surgery and the histologic effects of water jet resection on kidney tissue.

PATIENTS AND METHODS

A series of 24 patients underwent open surgery for renal-cell carcinoma, nephrolithiasis, complicated cysts, or oncocytoma. In tumor patients, a partial nephrectomy; in two stone patients, a nephrolithotomy; and in the third stone patient, a lower-pole resection were performed. The cysts and the oncocytoma were enucleated in toto. In one patient, an endoscopic pyeloplasty was performed because of ureteropelvic stenosis. Tissue samples were investigated histologically using standard light microscopy after hematoxylin-eosin staining and compared with those subjected to thermal dissection techniques.

RESULTS

The water jet produced a corridor in the desired dissection line without interfering with the intrarenal vessels and pelvicalical system. This way, precise hemostasis was possible, and damages to the surrounding tissue was avoided. Resection took between 14 and 40 minutes with minimal intraoperative blood loss. No significant postoperative complications occurred. Histologic evaluation demonstrated a sharp dissection line without thermal alterations or deep necrosis. Only a small disruption zone could be seen at the margins of the dissection.

CONCLUSIONS

Water jet resection is a gentle method for dissection of kidney tissue. Histologic examination confirmed minimal traumatic parenchymal alteration. In our opinion, the water jet dissector is a useful device for renal transection in organ-sparing kidney surgery.