Background
Histological evaluation of renal parenchyma is often essential in cases of several renal diseases with unexplained azotemia, proteinuria, hematuria, or systemic disease. Pathological diagnosis often provides useful information in determining the prognosis and guiding the treatment. Ultrasound-guided renal biopsy represents an essential step in the study of renal diseases [
1].
The last few decades have transformed the renal biopsy into a safe technique that plays a central role in the nephrological diagnostic approach [
2].
With percutaneous renal biopsy, as many as 5 to 20% of cases yield inadequate tissue for histopathology diagnosis. Moreover, percutaneous kidney biopsy is not without risk. Over complications occurring in up to 13% of the cases, and 6 to 7% of complications were considered major, needing for an intervention such as transfusion of blood product or invasive procedure (radiographic or surgical) [
3].
Difficulty in localized and inaccurate biopsies may be taken when patients are extremely obese, uncooperative, or have an ectopic kidney or abnormal body habitus [
4].
Gimenez et al. describes the first retroperitoneal laparoscopic renal biopsy technique in 32 patients who previously failed ultrasound-guided biopsy and in whom the approach was contraindicated [
5]. Relative indications for the laparoscopic approach include marked obesity [
6], failure of previous percutaneous biopsy attempts, a solitary kidney, a coagulopathy, Jehovah’s Witness faith, and in pediatric patients [
7]. Laparoscopic renal biopsy is preferred in which the retroperitoneal laparoscopic approach is able to obtain sufficient renal tissue, with minimal bleeding complications and a minimally invasive approach.
With advances in endoscopic instrumentation and the development of laparoscopic techniques, the minimally invasive renal biopsy is safety and preferable [
8]. Retroperitoneal laparoendoscopic single-site surgery (LESS) has been developed in an attempt to further reduce the morbidity and scarring associated with laparoscopic surgery. Early clinical series have demonstrated the feasibility of a broad range of retroperitoneal LESS urologic procedures [
9]. We present our preliminary experience with retroperitoneal LESS in a series of 14 subjects who required renal biopsy.
Discussion
Histological evaluation of renal parenchyma is often necessary in cases of several renal diseases. Pathological diagnosis often provides useful information in determining the prognosis and guiding the treatment [
11]. General indications for renal biopsy include renal failure—insufficiency of unknown etiology, nephrotic syndrome, proteinuria, and systemic diseases with suspected renal involvement such as systemic lupus erythematosus. Percutaneous renal biopsy is the most common method of sampling renal tissue because it is performed with local anaesthesia as outpatient surgery [
12].
In addition to the risk of bleeding and fistulae during percutaneous needle biopsy, the specimen can’t be adequate to have a histopathological diagnosis. In fact, during percutaneous procedures it is not easy obtain only cortex sample, that is necessary to study glomerular diseases. With LESS procedures, in our experience, we can select the best site in the kidney to perform the biopsy and we can take only cortex specimen, without medullary tissue.
In our experience percutaneous renal biopsy contraindications were uncontrolled hypertension, bleeding disorders, extreme obesity, and a solitary kidney.
With advances in endoscopic instrumentation and the development of laparoscopic techniques, the minimally invasive alternatives to open renal biopsy are safety and preferable. Although surgical approaches require general anesthesia, their advantage is that the kidney is identified, biopsied, and hemostasis is achieved under direct vision in a controlled fashion [
4]. Several papers in the last 20 years appeared in the literature describing the retroperitoneoscopic approach as safe and effective. Retroperitoneal access it is technically difficult due to the lack of landmarks, small working space, and loss of orientation. Relative simple procedures like renal biopsy are often performed in a retroperitoneoscopic fashion. Data shows that this approach for renal biopsy is effective also in less experienced surgeons. With minimal retroperitoneal dissection, the kidney is quickly identified and renal biopsy and haemostasis are safely achieved in a reasonably short period of time [
6‐
10].
As a result of the risks associated with additional ports, there has been a surge of interest in a less invasive alternative to retroperitoneoscopy. LESS has been developed in an attempt to further reduce the morbidity and scarring associated with laparoscopic surgery [
13]. Early clinical series have demonstrated the feasibility of a broad range of LESS urologic procedures [
14]. As a general principle, all eligible laparoscopic surgery patients can be considered for LESS depending on the surgeon’s experience.
In all patients the first trocar was positioned under direct vision using the Cannule Ternamian EndoTIP (Karl Storz®). This device allows the surgeon to open each tissue layer under direct vision, so that the surgeon has complete visual control to avoid blood vessels and nerves and to see the Scarpa’s fascia, the flank muscle, and the lumbodorsal fascia. Then, after insufflation with carbon dioxide at 15 mmHg, with this device we dissect bluntly the retroperitoneal space and mobilize the lateral peritoneal sheath from the anterior abdominal wall. This device is reusable, as compared to the Visiport access trocar (Covidien®) described in our previous experience in pediatric patients. This reusable device allows us to obtain results comparable to those with the Visiport access trocar, but with a reduction of the cost surgery [
8].
Our preliminary approach with LESS technique was a single-trocar renal biopsy, performed with an operative laparoscope (Karl Storz®) with a 5 mm working channel. This attempt was not effective because the operative laparoscope brought insufficient light into the operative field and forced the operator to be positioned too close to the operative field, with the kidney causing lens mist and other residue. In these cases we performed a hybrid LESS, without problem for the patients. In fact, there were no reported any intraoperative complication in these four cases, except for a slightly prolonged operative time. In the remaining ten patients we used a SILS Multiport (Covidien SILS™ Port) placed in the Petit’s triangle. Today many LESS ports, disposable and reusable, are available in the market. In this series we used the SILS port because, in our experience, it seems to be easy to place, standard trocars (5–10 mm) can be used, and retro-pneumoperitoneum can be maintained without leakage.
Compared to standard laparoscopy, LESS technique increases the difficulty of surgical procedures because of reduced workspace, the lack of triangulation, clashing of instruments, as has been reported in several case series [
8]. To reduce the risk of instruments clashing, we used two laparoscopes types: in four patients a bariatric 5 mm, 0° laparoscope (Karl Stortz®) was used, and in six patients a 5 mm flexible laparoscope EndoEye camera system (Olympus Medical) was used. With both lens devices we increase our working ability and improve our LESS technique. Moreover, the optic with which we obtained the best results was the EndoEye camera system. This device provides more light in the operating field, higher imaging quality, flexibility, and better working conditions. Our working strategy with the EndoEye system was to place the lens in a different plane of the instruments and compensate with the flexible tip (Figure
2).
Various disposable instruments have been developed to overcome the risk of clashing, minimal triangulation, and poor range of motion. Articulating instruments are designed to improve triangulation and external spacing for LESS procedures [
15]. In one case we used the “Roticulator Endo Grasp” (Covidien®) forceps and scissor. We used them to mobilize the lower pole of the kidney, transect Gerota’s fascia, and develop a fat window on renal parenchyma. We experienced a poor quality of the materials with the consequent breakage and deformation of the instrument’s tip. In one other case we tested the pre-bent instruments (Olympus Medical). These instruments have been introduced with the aim of minimizing instrument clashing outside the port, and providing triangulation in the operative field and better force distribution during dissection with the transperitoneal approach [
16]. In our experience these tools do not give better benefits because there is less working space in the retroperitoneal space compared to the abdominal cavity.
In our experience, all eligible laparoscopic surgery patients can be considered for LESS depending on the surgeon’s experience. According to recent updates from the Endourological Society NOTES (Natural Orifice Transluminal Endoscopic Surgery) and LESS Working Group and the European Society of Urotechnology NOTES, it has recently been stressed that LESS is appropriate in selected patients with limited previous abdominal surgery [
17]. Greco et al. suggest that malignant disease at pathology and high ASA score represent predictive factors for complications after LESS for upper urinary tract surgery. Thus, surgeons approaching LESS should start with benign diseases in low-surgical risk patients to allow an easier surgical approach and to minimize the risk of postoperative complications [
18].
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Competing interest
The authors declare that they have no competing interests.
Authors’ contributions
MS had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: ZA and MS. Acquisition of data: ZA and GR. Analysis and interpretation of data: ME. Drafting of the manuscript: ZA. Critical revision of the manuscript for important intellectual content: MS and BG. Administrative, technical, or material support: MP. Supervision: BG, CG and MS. All authors read and approved the final manuscript.