Laparoscopic partial nephrectomy with a diode laser: porcine results

Preclinical optimization of a diode laser-based clamp-free partial nephrectomy in a large animal model

Kidney cancer is a common urologic malignancy with either laparoscopic (LPN) or robotic partial nephrectomy as therapeutic options of choice for localized tumors. However, renal resection and suturing are challenging steps of the procedure that can lead to complications such as prolonged warm ischemia, bleeding, and urinary fistulas. LPN with a diode laser is an efficient technique due to its cutting and/or coagulation attributes. Surprisingly, key laser features such as wavelength and power remain undefined. Using a large porcine model, we evaluated the laser range of wavelength and power in a clamp-free LPN and compared it to the established gold-standard LPN technique (i.e., cold-cutting and suturing). By analyzing surgery duration, bleeding, presence of urine leak, tissue damage related to the resected renal fragment and the remaining organ, hemoglobin levels, and renal function, we show that an optimized experimental diode laser clamp-free LPN (wavelength, 980 nm; power, 15 W) had shorter surgery time with less bleeding, and better postoperative renal function recovery when compared to the well-established technique. Together, our data indicate that partial nephrectomy with a diode laser clamp-free LPN technique is an improved alternative to the gold-standard technique. Therefore, translational clinical trials towards human patient applications are readily feasible.

Lasers in laparoscopic and robotic surgery: is there a need for them

PURPOSE OF REVIEW

The application of lasers in treating urological disorders is a developing area. In the laparoscopic and robotic surgery, laser energy is not so popular as in the treatment of stone disease and benign prostatic hyperplasia. The aim of this review is to clarify the current status of laser applications in laparoscopic and robotic urology.

RECENT FINDINGS

Laser welding of the pyeloureteral anastomosis is not performed in routine clinical practice. Most investigation of laser applications in laparoscopic and robotic urology has centered on laparoscopic partial nephrectomy and robot-assisted partial nephrectomy. Much less work has been done with regard to lower tract laser laparoscopic and robotic applications. However, laser laparoscopic radical prostatectomy has been investigated.

SUMMARY

Current literature regarding lasers in laparoscopic and robotic surgery is extremely limited. Available data consist mostly of small cohorts providing a low level of evidence. Even though initial studies with currently available laser modalities demonstrated promising results, several drawbacks in each technique need to be addressed before being widely accepted as a standard care. Despite investigation, laser usage during laparoscopic and robotic urological procedures has not gained widespread acceptance and remains experimental at this time.

Usefulness of Thulium-Doped Fiber Laser and Diode Laser in Zero Ischemia Kidney Surgery-Comparative Study in Pig Model

Background: The aim of this study was to evaluate the usefulness of a thulium-doped fiber laser and a diode laser in zero ischemia kidney surgery, by carrying out a comparative study in a pig model. Material and methods: Research was carried out on 12 pigs weighing 30 kg each. A thulium-doped fiber laser (TDFL) and a diode laser (DL) operating at wavelengths of 1940 and 1470 nm, respectively, were used. The cut sites were assessed both macroscopically and microscopically. The zone of thermal damage visible in the histopathological preparations was divided into superficial and total areas. Results: During partial nephrectomy, moderate to minimal bleeding was observed, which did not require additional hemostatic measures. All animals survived the procedure. On day 0, the total thermal damage depth was 837.8 µm for the TDFL and 1175.0 µm for the DL. On day 7, the depths were 1556.2 and 2301.7 µm, respectively. On day 14, the overall thermal damage depth for the DL was the greatest (6800 µm). The width of the superficial zone was significantly reduced on days 7 and 14 after TDFL application. Conclusion: Both lasers are suitable for partial wedge nephrectomy without ischemia in pigs. The TDFL produced similar or better hemostasis than the DL, with a smaller zone of thermal damage and, therefore, seems more suitable for application in human medicine.

Diode Laser Vaporization for Benign Prostate Hyperplasia: Outcome After 126 Procedures

Purpose: Photoselective vaporization of the prostate (PVP) with a 940-nm diode laser is an option for treating symptoms caused by benign prostatic hyperplasia (BPH). Here, we present our experience using this technology. Methods: We prospectively evaluated 126 patients with lower urinary tract symptoms (LUTS) secondary to BPH who underwent PVP with a 940-nm diode laser from January 2011 to January 2014. The patients were assessed using the International Prostate Symptom Score (IPSS), quality of life (QoL) score, prostate-specific antigen (PSA) level, maximum urinary flow (Qmax) by uroflowmetry, postvoid residual volume, and prostate volume by ultrasound at baseline and 3, 6, 12, and 24 months after the procedure. Results: The average patient age was 68.8 ± 8.7 years (range 48-90 years), whereas the average preoperative parameters were as follows: IPSS, 26.1 ± 5.2; IPSS-QoL, 4.9 ± 0.8; Qmax, 4.5 ± 3.1 mL/s; prostate volume, 76.5 ± 35.5 mL; and PSA level, 3.9 ± 2.6 ng/mL. The average catheterization time was 24.7 ± 25.5 hours (range 3-120 hours), and the length of hospital stay was 22.4 ± 17.0 hours (range 8-144 hours). The mean follow-up duration was 17.9 months (range 1-36 months). All parameters showed significant improvement after 12 months. After 24 months, the IPSS (8.8 ± 5.4, p < 0.07), IPSS-QoL (1.6 ± 0.9, p < 0.13), Qmax (15.9 ± 7.3 mL/s, p < 0.11), and PSA level (1.2 ± 0.8 ng/mL, p < 0.11) were improved compared with the baseline, but the difference was not significant, probably due to the small number of patients evaluated in this period. No patients required a transfusion. Conclusions: The results suggest that PVP with a 940-nm diode laser is safe, effective, and durable for the treatment of LUTS secondary to BPH. The patients continue to be monitored for evaluation of the long-term results. A prospective randomized study would allow more solid conclusions regarding the technology to be reached.

Laparoscopic partial nephrectomy with diode laser: a promising technique

OBJECTIVE

The aim of this study was to evaluate application of diode laser in laparoscopic partial nephrectomy (LPN), and to question this technique in terms of ease of tumor excision and reduction of warm ischemia time (WIT).

BACKGROUND DATA

LPN is the standard operative method for small renal masses. The benefits of LPN are numerous, including preserving renal function and prolonging overall survival. However, reduction of WIT remains main challenge in this operation. In order to shorten WIT, many techniques have been developed, with variable results.

PATIENTS AND METHODS

We performed a prospective collection and analysis of health records for patients who were operated on between March 2011 and August 2012. Inclusion criteria were single tumor ≤ 4 cm, predominant exophytic growth and intraparenchymal depth ≤ 1.5 cm, with a minimum distance of 5 mm from the urinary collecting system.

RESULTS

We operated on 17 patients. Median operative time was 170 min. In all but two patients, we had to perform hilar clamping. Median duration of WIT was 16 min. Pathohistological evaluation revealed clear cell renal cancer and confirmed margins negative for tumor in all cases. Median size of the tumor was 3 cm. Median postoperative hospitalization was 5 days. Average follow up was 11.5 months. There were no intraoperative complications. One postoperative complication was noted: perirenal hematoma.

CONCLUSIONS

Laser LPN is feasible, and offers the benefit of shorter WIT, with effective tissue coagulation and hemostasis. With operative experience and technical advances, WIT will be reduced or even eliminated, and a solution to some technical difficulties, such as significant smoke production, will be found.

[Laser now also to be used in organ-preserving kidney surgery?]

Kidney surgery is subject to continuous change. Partial nephrectomy is the prevailing method for small and medium-sized tumours and proven to be superior to radical nephrectomy. The conventional technique usually includes clamping the renal vessels. The duration of the ischaemia caused determines the outcome of the remaining renal function. The shorter the ischaemic time the more likely the renal function will be preserved. Thus, new techniques are needed to abandon renal vessel clamping. Essential is a combination of good cutting abilities and assured haemostasis. To date, the commonly used techniques for cutting in partial nephrectomy only partially fulfil these requirements. Establishment of laser in urology offers a new surgical technique that combines both. In spite of the still limited data on laser use in kidney surgery, this method can be assessed favourably. Laser offers a possibility of both open and laparoscopic partial nephrectomy avoiding renal vessel clamping without additional risks or complications.

Influence of irrigation on incision and coagulation of 2.0-μm continuous-wave laser: an ex vivo study

BACKGROUND

Several lasers are suitable for laparoscopic surgery but with remarkable smoke formation, which compromises surgical visibility and safety. Slow irrigation eliminates laser smoke efficiently, but gives rise to the concern of reducing the laser incision and coagulation efficiency.

METHODS

Canine kidney specimens were manually cut with a 2-μm continuous-wave Thulium-YAG laser. Two laser powers (20 and 40 W) combined with 3 irrigation rates (0, 20, and 80 mL/min) were experimented. The depth of the cutting slot and the thickness of the coagulation layer were measured microscopically and compared statistically between different setting combinations using 2-way analysis of variance.

RESULTS

The incision depth was decreased significantly at high (80 mL/min) but not low rate (20 mL/min). The thickness of the coagulation layer changed insignificantly with the irrigation rate.

CONCLUSIONS

Slow irrigation had an acceptable influence on the incision and the coagulation ability of 2.0-μm continuous-wave laser and is suitable and efficient to address the smoke issue in laser laparoscopic surgery.

Ex vivo comparison of the tissue effects of six laser wavelengths for potential use in laser supported partial nephrectomy

Laparoscopic/robotic partial nephrectomy (LPN) is increasingly considered for small renal tumors (RT). This demands new compatible surgical tools for RT-resection, such as lasers, to optimize cutting and coagulation. This work aims to characterize ex vivo handling requirements for six medically approved laser devices emitting different light wavelengths (940, 1064, 1318, 1470, 1940, and 2010 nm) amenable for LPN. Incisions were made by laser fibers driven by a computer-controlled stepping motor allowing precise linear movement with a preset velocity at a fixed fiber-tip distance to tissue. Optical parameters were measured on 200 μm tissue slices. Cutting quality depended on power output, fiber velocity and fiber-tip distance to tissue. Contact manner is suitable for cutting while a noncontact manner (5 mm distance) induces coagulation. Ablation threshold differs for each wavelength. Ablation depth is proportional to power output (within limit) while axial and superficial coagulation remains mostly constant. Increased fiber velocity compromises the coagulation quality. Optical parameters of porcine kidney tissue demonstrate that renal absorption coefficient follows water absorption in the 2 μm region while for other spectral regions (900 to 1500 and 1 μm) the tissue effects are influenced by other chromophores and scattering. Tissue color changes demonstrate dependencies on irradiance, scan velocity, and wavelength. Current results clearly demonstrate that surgeons considering laser-assisted RT excisions should be aware of the mentioned technical parameters (power output, fiber velocity and fiber-tip tissue-distance) rather than wavelength only.

GreenLight HPS laser 120-W versus diode laser 200-W vaporization of the prostate: comparative clinical experience

BACKGROUND AND OBJECTIVE

We present our clinical experiences of two recently introduced vaporization laser systems: the GreenLight High Performance System (HPS) laser (532 nm, 120 W) and the Diolas LFD diode laser (980 nm, 200 W).

MATERIALS AND METHODS

Two laser systems were evaluated to compare their clinical results for the treatment of benign prostatic hyperplasia (BPH). Patients were treated using either the GreenLight HPS laser (n = 84) or the diode laser (n = 55) in a prospective randomized study. The data of International Prostate Symptom Score (IPSS), maximum flow rate (Q(max)), post-void residual urine (PVR), and quality of life score (Qols) were recorded at baseline, 1-, 6-, and 12-month follow-ups. The prostate volume and prostate-specific antigen (PSA) level were assessed at baseline and 6-month follow-up. All complications were also recorded.

RESULTS

There was a statistically significant difference in IPSS, Q(max), PVR, and QoLs in each laser group at the 1-, 6-, and 12-month follow-ups compared with baseline. There was no statistical significant difference in any of these parameters at any follow-up interval between each group. The diode laser demonstrates superior hemostatic properties compared with the GreenLight HPS laser. Postoperative incontinence and postoperative irritative symptoms are more pronounced (P < 0.05) after diode laser prostatectomy. Higher incidence of dysuria with sloughing tissues and epididymitis (P < 0.05) is noted after diode laser prostatectomy. Other complications were comparable for both procedures.

CONCLUSIONS

Although both lasers can improve subjective and objective parameters of BPH, both can produce undesired effects. The search for the ideal vaporization laser to treat BPH still continues.

Comparison between a 1.92-μm fiber laser and a standard HF-dissection device for nephron-sparing kidney resection in a porcine in vivo study

Nephron-sparing surgery was performed in a porcine model with a 1.92-μm fiber laser dissection device in comparison to a standard high-frequency dissection device. In nine pigs, general anesthesia and a median laparotomy were performed to expose both kidneys. On six kidneys (three HF and three laser) a partial renal parenchyma resection of the lower pole without opening of the renal pelvis was performed (group A). On 12 kidneys (four HF and eight laser), a hemi nephrectomy with opening of the renal pelvis was performed (group B). Total resection time including hemostasis of the remaining tissue was 501 ± 394 s in group "A-laser " vs. 176 ± 139 s in group "A-HF". For the group "B", the total resection time was 1174 ± 501 s (B laser) vs. 960 ± 407 s (B-HF). Blood loss was 28 ± 22 ml in group "A laser " vs. 15 ± 15 ml in group "A-HF". In group "B", the blood loss was 98 ± 73 ml (B laser) vs. 137 ± 118 ml (B-HF). No ischemic time for the kidneys was needed in group "A" for both dissection devices. In group "B", ischemia of the kidneys was performed three times during the eight laser procedures (420 ± 60 s) and only once at the four HF procedures (1,260 s). Healing process was observed over 4-6 weeks, survival rate was 100%, and no renal fistulas were found after the survival period. In conclusion, no significant differences were found between the compared dissection devices. However, the laser system with the flexible transmission fiber may have an advantage for a laparoscopic approach by steerable instruments.

Advances in laser technology in urology

Since the Ruby laser was first developed in 1960 as the first successful optical laser, laser energy has continued to be developed and used in industry and medicine alike. Laser use in urology has been limited, however, largely until the last decade. The unique properties of laser energy have now led to its widespread use within urology, particularly in the treatment of benign prostatic hyperplasia, urolithiasis, stricture disease, and novel laparoscopic applications. This article details laser developments in each of these areas.

Practical hints for hemostasis in laparoscopic surgery

With the developments achieved in recent years in laparoscopic surgery, the field has acquired a host of new techniques to achieve haemostasis, allowing the surgeon to tackle complex procedures. These techniques include physical modalities (as simple as compression or suturing and as sophisticated as endovascular staples), thermal modalities (such as bipolar coagulation, laser or ultrasonic dissectors), and topical sealants (e.g. Fibrin glue or gelatine matrix). It is up to the laparoscopic surgeon to be familiar with all these different modalities and their proper use and limitations. It should also be kept in mind that the best approach to haemostasis in laparoscopy is prevention by thorough case preparation and meticulous dissection technique. We herein expose an overview of the available techniques to achieve haemostatic control in laparoscopic surgery in the emergency as well as the elective setting. Representative surgeries are used for illustrative purposes to describe special manoeuvres.

Haemostasis in laparoscopic partial nephrectomy: Current status

Laparoscopic partial nephrectomy (LPN) is increasingly performed all over the world. However, as in its open counterpart, achieving a satisfactory haemostasis may be challenging. Our goal is to describe the different methods employed to control bleeding during LPN. We performed a non-structured review of the literature on the different haemostatic methods used during LPN. The techniques and materials used are divided into two main groups: LPN with ischemia and LPN without ischemia. The techniques to achieve warm, cold and regional ischemia are described. Energy sources and sealants are discussed in the section on LPN without ischemia. Case selection is of capital importance in the choice the appropriate haemostatic tools for LPN. Some refinements, related to the nature of the laparoscopic procedure, are still required to reach an effective cold ischemia. A broad variety of energy sources have been tested in animal models and in human setting. Major disadvantages are tissue scarring, smoke creation and low progression speed. To date none has been demonstrated to be superior to the conventional suturing. Fibrin and thrombin promoters as bio-glues are an important adjuvant method during LPN. Bipolar current devices together with fibrin sealants or coagulation promoters are used in small peripheral tumors. In bigger or central tumors, additionally suturing over Surgicel bolsters, the most popular technique is to secure the suture by means of clips. The level of the recommendations is based on comparative cohorts. We conclude that haemostasis is achieved during LPN adapting the protocols used in open nephron sparing surgery to the laparoscopic approach. Renal ischemia and bolster sutures are still mandatory in complicated LPN while in case of small exophytic tumors a satisfactory haemostasis may be achieved by using only a sealant product.

Less smoke and minimal tissue carbonization using a thulium laser for laparoscopic partial nephrectomy without hilar clamping in a porcine model

PURPOSE

We evaluated the utility of a thulium laser and a novel implementation of its use for laparoscopic partial nephrectomy to achieve precise, smokeless, and hemostatic dissection without hilar clamping and with minimal charring in a porcine model.

MATERIALS AND METHODS

Laparoscopic transperitoneal lower-pole partial nephrectomy was performed in five Yorkshire farm pigs without clamping of the renal hilum. All animals were kept alive for 1 week. Using a 365-mum laser fiber, a 30 W thulium laser was used to produce full-thickness cortical excisions of the lower-pole renal cortex. The laser fiber was delivered through the working channel of a 16F flexible cystoscope inserted through a 10-mm laparoscopic port. The laser incision was directed by manual deflection of the cystoscope along with low-pressure saline irrigation through the cystoscope.

RESULTS

Laparoscopic partial nephrectomy was completed in all cases without perioperative complications and with an estimated blood loss of <50 mL. The thulium laser was able to cut tissue and simultaneously to coagulate vessels as large as 1.6 mm. The flexible cystoscope with concurrent saline irrigation permitted precise laser control for dissection with minimal tissue charring and no smoke to obscure visibility. At 1 week, the cut edge of the tissue showed minimal necrosis with preservation of histologic architecture.

CONCLUSIONS

Laparoscopic partial nephrectomy with the thulium laser provides precise dissection and hemostasis without hilar clamping. Minimal tissue charring and no smoke generation improve visibility.

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.

Large-Volume Laparoscopic Partial Nephrectomy Using the Potassium-Titanyl-Phosphate (KTP) Laser in a Survival Porcine Model

OBJECTIVES

Laparoscopic partial nephrectomy (LPN) remains a technically challenging procedure primarily because of difficulties with hemostasis. In an attempt to develop a hemostatic cutting instrument for laparoscopic partial nephrectomy, we evaluated the potassium-titanyl-phosphate (KTP) laser for use during large-volume laparoscopic partial nephrectomy in a porcine model.

METHODS

Transperitoneal lower pole laparoscopic partial nephrectomy was performed in six pigs. Two nonsurvival animals were used initially to develop the laser technique. Four animals underwent a right-sided laparoscopic laser partial nephrectomy followed by an identical left-sided procedure 2 weeks later. Renal hilar occlusion was used in all cases. A novel 365-mum end-firing laser fibre and 80-W KTP laser were used for resection and hemostasis. All renal remnants underwent retrograde pyelography and histologic examination.

RESULTS

Laser resection and hemostasis was successfully completed in all cases, and no perioperative complications occurred. Mean estimated blood loss was 80 ml (25-250 ml). Mean laser and warm ischemia times were 35 and 34 minutes, respectively. Resection speed was limited by smoke formation but not by cutting or hemostatic efficiency of the laser. Mean resected kidney mass was 30 g or 25% of total kidney mass. There were no urinomas, but, on retrograde pyelogram, extravasation was noted in seven of eight kidneys (87.5%).

CONCLUSIONS

The KTP laser provides hemostasis during large-volume resection in the porcine kidney. This technique appears promising for laparoscopic partial nephrectomy in humans.

Laparoscopic partial nephrectomy with saline-irrigated KTP laser in a porcine model

PURPOSE

To evaluate the feasibility of using the potassium titanyl phosphate (KTP) laser to perform laparoscopic partial nephrectomy in a porcine model, with saline irrigation to reduce intraoperative smoke formation.

MATERIALS AND METHODS

A high-power (80 W) KTP laser was used without hilar occlusion in 14 laparoscopic partial nephrectomies in four pigs. During laser discharge, the cutting plane was irrigated continuously with saline.

RESULTS

Thirteen partial nephrectomies were completed. Hemostasis was obtained without the need for any non-laser techniques. Only minimal smoke was produced, not affecting visibility or the progress of surgery. Histologic examination of the resection margin showed only minimal tissue destruction. One procedure failed because the laser fiber broke and occluded the suction during the operation. The mean partial nephrectomy time was 13.14 minutes (range 7-19 minutes) with a mean estimated blood lost of 28.57 mL (range 5-80 mL). The mean saline irrigation used for each operation was 2600 mL (range 1500-3400 mL), and the amount of saline drained out was 1700 mL (range 900-3200 mL).

CONCLUSION

Laparoscopic partial nephrectomy using the 80 W KTP laser is feasible and effective in the porcine model. Saline irrigation dramatically reduces smoke formation. The technique is deserving of clinical studies after the laser-application device and suction irrigation are refined.

Evaluation of polyethylene glycol based hydrogel for tissue sealing after laparoscopic partial nephrectomy in a porcine model

PURPOSE

Polyethylene glycol (PEG) based hydrogel is available as a tissue sealant and hemostatic aid. We determined the long-term safety and efficacy of its use as a tissue sealant for laparoscopic partial nephrectomy in a porcine model.

MATERIALS AND METHODS

A total of 16 swine were cycled to 1 control group and 3 treatment groups, which underwent laparoscopic partial nephrectomy with hemostasis achieved only with application of a biodegradable PEG based hydrogel. The 3 treatment groups were sacrificed at 2, 6 and 12 weeks, respectively. Humoral immune response to the hydrogel used in the porcine abdomen was examined using enzyme-linked immunosorbent assay to detect antibodies in the serum at 0, 2, 6 and 12 weeks. Cell mediated immune response was examined using a lymphocyte proliferation assay to measure the response of leukocytes to various mitogens and antigens, including the polymerized hydrogel, at the same intervals.

RESULTS

Hemostasis was satisfactory after hydrogel application. No adverse effects in the immediate and delayed periods were noted. At 2, 6 and 12 weeks there were no significant differences in hemoglobin or creatinine levels, or in the humoral immune response by enzyme-linked immunosorbent assay. There was no significant difference between test and control pig reactivity to hydrogel as an antigen in the lymphocyte proliferation assay at any time point. Histologically by 6 weeks the animals had almost absorbed the hydrogel with acute inflammation and foreign body reaction resolving by 6 to 12 weeks. No deleterious effect to renal tubules was seen.

CONCLUSIONS

Biodegradable PEG based hydrogel is effective for long-term use as an agent for hemostasis. There was no detectable humoral immune response and no cell mediated immune response to sealant after 2 weeks. This represents promising sealant technology and it should be further investigated for human use.

Laparoscopic partial nephrectomy using the potassium titanyl phosphate laser in a porcine model

INTRODUCTION

To evaluate the potential and feasibility of the potassium titanyl phosphate (KTP) Greenlight laser to perform partial nephrectomy in a porcine model.

TECHNICAL CONSIDERATIONS

A total of 15 laparoscopic partial nephrectomies were performed in 4 Danish land-raised pigs under anesthesia. Transperitoneal access was obtained, and using a total of four ports, the 80-W KTP laser was used to perform bilateral upper and lower pole partial nephrectomy. The procedures were done successfully without renal cooling or clamping of the vessels. The estimated blood loss for each procedure was less than 30 mL. Only in one operation, in which a secondary renal vein was transected, was any additional hemostasis required (a single Endoclip). The mean operating time was 42 minutes (range 31 to 59) for each partial nephrectomy. As demonstrated on video, smoke formation was, at times, a problem during the procedure, because it reduced visibility, making only intermittent application of laser energy possible. Histopathologic analysis of the specimens showed a zone of loss of substance (less than 1 mm) at the resection line and narrow adjacent zones on both sides of the resection line with minimal changes.

CONCLUSIONS

We have shown for the first time that normally perfused laparoscopic partial nephrectomy using the KTP laser is feasible and efficacious in the porcine model. This represents a novel application for the KTP laser, which produced excellent renal parenchymal hemostatic ablation. We are currently working on ways to improve the visibility by reducing smoke formation before undertaking a clinical trial in humans.

Haemostasis in laparoscopy

OBJECTIVE

Adequate haemostasis is essential for advanced laparoscopic procedures since uncontrolled bleeding may cause significant complications and even required converting to laparotomy to obtain sufficient haemostasis. The aim of this review is to give insight into the most important tools and strategies to achieve sufficient haemostasis during advanced urologic laparoscopy.

METHODS AND RESULTS

Lowering the risk of haemorrhage may be achieved primarily by proper case selection, resulting in adequate laparoscopic preparation and dissection technique or the use of local compression by sponge stick to control local bleeding. For early bleeding control, laparoscopic clip appliers, staplers and suturing techniques may be utilised. Various energy sources such as monopolar and bipolar electrocautery, argon beam coagulators, laser or ultrasonic dissectors and topical sealing agents can be used to augment natural haemostasis.

CONCLUSIONS

A wide armamentarium for achieving haemostasis during laparoscopy is available. Consequently, laparoscopic surgeons must have detailed knowledge of the physical concepts of each surgical instrument or energy source and of proper use of tissue sealants for obtaining sufficient haemostasis. This knowledge will improve postoperative outcome, increase patient safety and guide laparoscopic techniques to further perspectives.

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.

Evaluation of Hydrogel Tissue Sealant in Porcine Laparoscopic Partial-Nephrectomy Model

BACKGROUND AND PURPOSE

Laparoscopic partial nephrectomy (LPN) is technically challenging with a steep learning curve, primarily because techniques used to control bleeding on the cut surface of the kidney can be ineffective, inconsistent, or challenging. Hemostatic techniques can include intracorporeal suturing, vascular coagulation (argon-beam coagulator, bipolar cautery, laser), and application of various tissue sealants. There is no uniformity of opinion regarding which hemostatic technique is optimal for this application. CoSeal, a hydrogel (Baxter Healthcare Corp, Deerfield, IL), has been effective following vascular surgery but has not been applied to a partial-nephrectomy model. We evaluated the effectiveness of this hydrogel in controlling bleeding and sealing the collecting system by comparing it with intracorporeal suturing and fibrin sealant (Tisseel; Baxter) in a porcine laparoscopic partial-nephrectomy model.

MATERIALS AND METHODS

Bilateral synchronous upper-pole partial nephrectomies were performed in two groups of 18 farm pigs, and the three hemostatic techniques (suturing, Tisseel, CoSeal) were applied. In the first group, partial nephrectomies were performed and the pigs sacrificed 3 days postoperatively (acute group). In the second group, the pigs were euthanized 6 weeks postoperatively (chronic group). In both groups, weight, blood pressure, estimated blood loss, weight of the partial and completion nephrectomy specimen, presence/ absence of urinary leak on retrograde study, histopathologic findings, and complications were recorded.

RESULTS

The mean weight, blood pressure, estimated blood loss, histopathology findings, and weight of the partial and completion nephrectomy specimens were similar in the three groups. CoSeal did not adhere well to the renal parenchyma compared with Tisseel. All three animals in the acute CoSeal group and three of the six pigs in the sutured group had small urinary leaks during retrograde ureteral study, whereas none of the pigs in the fibrin-glue cohort had urinary leaks. There was one complication (urinary leak) in the CoSeal group, necessitating sacrifice of the animal on postoperative day 8 because of sepsis.

CONCLUSIONS

CoSeal is not as effective as fibrin glue in adhering to the cut renal surface and sealing the collecting system during laparoscopic partial nephrectomy.

APPLICATION OF NOVEL HEMOSTATIC AGENT DURING LAPAROSCOPIC PARTIAL NEPHRECTOMY

PURPOSE

We determined if QuikClot, a novel hemostatic agent made of a granulated mineral substance, could be used to control renal parenchymal bleeding and collecting system leakage during open and laparoscopic partial nephrectomy.

MATERIALS AND METHODS

After obtaining renal hilar vascular control 2 domestic female pigs underwent bilateral open and 4 underwent unilateral laparoscopic partial nephrectomy. After excision of the lower pole without cautery the hemostatic agent was applied to the cut surface of the kidney and hilar vascular control was released. Additional QuikClot was added until complete hemostasis was achieved. One week postoperatively the animals were sacrificed and the operated kidneys were harvested for ex vivo retrograde pyelograms and histopathological analysis.

RESULTS

All partial nephrectomies were performed without complication. Mean operative and warm ischemia times were 62 and 16 minutes, respectively. An average of 23% of renal mass by weight was resected with a mean blood loss of 73 ml per procedure. No cautery, additional hemostatic agents or techniques were used. No animal had clinical or radiographic evidence of urinoma or delayed hemorrhage. Histopathological analysis showed preservation of the renal parenchyma immediately beneath the QuikClot layer.

CONCLUSIONS

In the porcine model QuikClot allowed the resection of large renal segments, while providing reliable hemostasis and closure of the renal collecting system. No deleterious effect on underlying renal parenchyma or surrounding tissues was observed.

PIG KIDNEY: ANATOMICAL RELATIONSHIPS BETWEEN THE INTRARENAL ARTERIES AND THE KIDNEY COLLECTING SYSTEM. APPLIED STUDY FOR UROLOGICAL RESEARCH AND SURGICAL TRAINING

PURPOSE

We present a systematic study of the anatomical relationships between intrarenal arteries and the kidney collecting system in pigs.

MATERIALS AND METHODS

The intrarenal anatomy (collecting system and arteries) was studied in 91, 3-dimensional endocasts of the kidney collecting system together with the intrarenal arteries.

RESULTS

Some anatomical details that have importance to help research and surgical training in urology when using the pig as an animal model were observed and described. It was found that there was only 1 artery per kidney. This artery divided into cranial and caudal branches in 85 cases (93.4%). In 6 cases (6.6%) the primary division of the renal artery was in a dorsal and in a ventral branch. In all cases 2 arteries (1 ventral and 1 dorsal) involved the cranial caliceal group. In the dorsal mid zone a dorsal artery originated from the cranial division of the renal artery, which was obliquely positioned in 47.25% of cases. The arterial supply related to the ventral mid zone of the kidney consisted of branches that coursed horizontally in the ventral surface of the renal pelvis in 81.32% of cases. The caudal division of the renal artery supplied the ventral and dorsal surfaces of the caudal caliceal group in 84.62% of cases, while in 15.38% a dorsal artery supplied its dorsal surface.

CONCLUSIONS

Although the results of renal and intrarenal anatomy in pigs could not be completely transposed to humans, many similarities in the pig and human intrarenal arteries support its use as the best animal model for urological procedures.

Hand-Assisted Laparoscopic Partial Nephrectomy

The resurgence of nephron-sparing surgery for selected renal masses has fueled interest in minimally invasive approaches. Several authors have shown that laparoscopic partial nephrectomy is feasible if two goals are met: resection of the mass with negative margins and control of bleeding. The latter is a particular challenge, but numerous options are available. The authors describe the operative technique and the available results of hand-assisted laparoscopic partial nephrectomy.