1. Introduction

The nephrectomy procedure was introduced to the practice of surgeons in XIX century. Based on this experience, the approaches, technical details, steps of the operation has been changed and modified and has become a standard all over the world for the treatment of different renal diseases [1,2].

In 1990, Clayman et al. [3] performed the first laparoscopic nephrectomy and this method popularized worldwide. The technical difficulties of accessing the retroperitoneal space and the impossibility to create an effective and enough large pneumoretroperitoneum were overcome in 1992 by the introduction of the balloon dissection technique by Gaur [4]. This new approach then was modified and enabled the performance of different retroperitoneoscopic (RP) procedures [5,6]. But, despite the technical feasibility, current use of the retroperitoneal approach is not so much popular among urologists. In this study, we have comparatively evaluated our experience with the RP and with open nephrectomy (ON) performed in our clinic. These two groups have been balanced in terms of indications (table 1) and compared with respect to operative time, morbidity, blood loss, dose of analgesic use, postoperative mean visual analogue pain score (at third day) and postoperative hospital stay.

2. Material and Methods

Clinical data of 347 patients who underwent nephrectomy from January 2019 to December 2019 in Republican Specialized Scientific-practical Medical Center of Urology were analyzed retrospectively. The most common indication for both groups were scarred (nonfunctioning) kidney. Patient with suspected or confirmed malignancy were excluded from the analysis. Preoperative management included transabdominal ultrasound and urinalysis with culture, KUB film and intravenous urography or/and computed tomography (CT) urography, serum creatinine, complete blood count and basic metabolic panel. The American Society of Anesthesiologists (ASA) grading system was used to assess the patient’s physical condition and surgical risk.

All patients were divided into 2 groups corresponding the surgical procedure. Patient selection was based upon referral, requesting either a laparoscopic or an open surgical approach, or depending on the previous surgical procedures and the complexity of the clinical case. First group included 180 patients who underwent retroperitoneoscopic (RP) nephrectomy and second group was control group and consisted from 167 patients who underwent open nephrectomy for various etiology kidney diseases.

Basic characteristics of patients are shown in table 1.

Table 1. Table of baseline characteristics of patients

Patients had different pathologies, which were indications for nephrectomy. Indications for nephrectomy in both groups are summarized in table 2.

Table 2. Indications for nephrectomy in both groups

We used the standard technique for the RP procedure.

RPN. In contrast to the transperitoneal approach, 3 reusable, valved metal trocars were predominantly utilized (2-10 mm, 1–5 mm). Balloon dissection technique according to Gaur was accomplished to create retroperitoneal access. We used standard instruments for dissection. Titanium clips and Hem-o-lok clips were used on demand to clip the ureter, renal artery and vein.

Patient Preparation: All patients received similar perioperative treatment which included preoperative bowel preparation, cross-matching of blood, peri-operative antibiotics, deep vein thrombosis prophylaxis with low-molecular heparin and elastic stockings and a signed informed consent form.

Patient Positioning: Patients positioned in lumbotomy position and employed the standard technique described by Rassweiler [5,6]. After balloon dissection of the retroperitoneal space we applied three trocars and the Gerota’s fascia was incised widely and the ureter explored. The dissection of the renal pedicle was routinely performed dorsally and renal vessels were clipped separately and transsected.

For the open removal of the kidneys, the technique of the supracostal lumbotomy above the 11th or 12th rib was used [1]. After incision of the Gerota’s fascia, the kidney and ureter were isolated. The pedicle was dissected dorsally with transection and ligation of the renal vein and artery.

At the end of both procedures a drain was left in retroperitoneal space.

In both groups, we analyzed the parameters of clinical outcome such as total blood loss, incision length, duration of surgical procedure, doses of nonsteroidal anti-inflammatory drugs used after surgery for pain relief and postoperative hospital stay. We also assessed postoperative complications. Postoperative complications have been classified according to modified classification of Clavien-Dindo [7].

All relevant data were statistically analyzed. For normality testing we used Kolmogorov-Smirnov test and Shapiro-Wilk test. Student's t-test and Mann-Whitney U Test for continuous variables and Chi-Square tests for categorical variables were used to examine mean and proportional differences. p value < 0.05 was considered statistically significant.

3. Results

The median amount of estimated blood loss was 10 (10-400, IQR-40) mL for RP nephrectomy group and 100 (25-400; IQR-100) mL for ON group, which reliably shows that RP nephrectomy is accompanied by less blood loss (p < 0.001).

Figure 1. Box plot chart for comparison of intraoperative blood loss in both groups in mL (p < 0.001). Note: outliers in this graph are not shown

3 (1.66%) patients in RP nephrectomy group had intraoperative blood loss more than 500mL, which didn’t required blood transfusion. In contrast, in open nephrectomy group 12 (7.18%) patients had blood loss more than 500 mL and 10 of them required blood transfusion.

The median incision length in RP nephrectomy was 60 mm (40-100 mm; IQR – 30) - in the iliac region, and in open nephrectomy, - thoracolumbotomy, 150 mm (100–230 mm: IQR – 30), which reliably proves that RP nephrectomy cause less trauma to patient and has a better cosmetic results (p < 0.001) than open nephrectomy.

Figure 2. Box plot chart for comparison of incision length in both groups in mm (p < 0.001)

The median operative time was 90 min (20-210 min; IQR - 45) for RPN and 80 min (60-180 min; IQR - 15) for ON (Fig. 3). The operative time mainly depended in two groups on the individual intra-operative situation, such as size of the kidney or degree of perinephric adhesions. Results of statistical analysis show that operative time is not significantly different in both groups (p = 0.711).

Figure 3. Box plot chart for comparison of operative time in both groups in min (p = 0.711)

Doses of nonsteroidal anti-inflammatory drugs (diclofenac) used after surgery for pain management were significantly different in both groups (p < 0.001): in RP nephrectomy group median doses of diclofenac used postoperatively was 150 mg (0-375 mg; IQR-150); in open nephrectomy group – 225 mg (0–1025 mg; IQR-225) for a hole hospital stay period.

Figure 4. Box plot chart for comparison of diclofenac doses for postoperative pain relief in both groups in mg (p < 0.001)

The median postoperative hospital stay was 2 days (1-12 days; IQR-1) in RP nephrectomy group, in contrast 5 days (2–14 days; IQR-2) in open nephrectomy group, which is significantly higher in ON group (p < 0.001).

Figure 5. Box plot chart for comparison of postoperative hospital stay time in both groups in days (p < 0.001)

Complications.

In ON group in 33 (19,76%) patients we observed postoperative complications. Among them 15 (8.98%) patients developed incision site infection, in 5 (2.99%) patients there was bleeding from retroperitoneal drainage, which required to increase in draining time. Postoperatively 5 (2.99%) patients had bowel dysfunction, in 1 (0.6%) patient developed hospital acquired pneumonia, in 2 (1.2%) patients - myocardial infarction and acute cerebrovascular accident, in 3 (1.8%) patients – sepsis, in 1 (0.6%) patient – intestinal fistula. 1 (0.6%) patient died due to sepsis syndrome and multiorganal failure.

In RPN group in 16 (8.89%) we observed postoperative complications. Among them 7 (3.9%) patients developed incision site infection, in 2 (1.11%) patients there was bleeding from drainage, in 6 (3.33%) patients had bowel dysfunction. 1 (0.55%) patient developed mild brachial plexopathy, which treated by the administration of analgesia and muscle relaxers.

The complications are summarized in table 3 and classified according to modified classification of Clavien-Dindo scale [7] in Table 4.

Table 3. Frequency of postoperative complications in both groups

Table 4. Frequency of classified of postoperative complications according to classification of Clavien-Dindo

4. Discussion

Minimally invasive methods of simple or radical nephrectomy (laparoscopic, retroperitoneoscopic) are replacing the conventional open nephrectomy. The revealed benefits of retroperitoneoscopic approach are patient comfort, improved cosmetic result and shorter convalescence [8].

As originally described by Clayman et al. [3], the technique of laparoscopic nephrectomy included several steps: re-positioning of the patient from the supine to the lateral decubitus position after obtaining a pneumoperitoneum. Furthermore, dissection of the colon, which is performed in order to gain access to the retroperitoneum, could be the risky of injury to the liver or spleen. These disadvantages supported the search for standardizing a retroperitoneal approach which – as being similar to the open access [1] – could hopefully overcome these problems.

In 1992, Gaur [4] introduced his revolutionized technique based on the insufflation of a special balloon catheter which allowed properly dissect the retroperitoneum and he has reported his experience with the first retroperitoneal laparoscopic nephrectomy [12]. In 1994, Rassweiler JJ et al. described their similar balloon dissection technique based on a hydraulic mechanism [13,14].

There are some absolute contraindications for the transperitoneal laparoscopic approach, like a history of or active peritonitis, markedly distended bowel, extensive adhesions from prior surgery, uncorrected coagulopathy and hypovolemic shock [13,15,16]. However, in the case of retroperitoneal procedures, previous open abdominal surgery or history of peritonitis are not necessarily regarded as contraindications. But, severe perinephric adhesions due to previous lumbotomies, paranephritis, xanthogranulomatous pyelonephritis, renal tuberculosis, post-traumatic renal atrophy or post-embolization nephrectomies may make retroperitoneoscopic approach mostly impossible [14].

It has noted that even among healthy patients for the open donor nephrectomy a 3.5% major complication rate and up to 30% minor complication rate were described. The operative time, although brief (90–140 min), is followed by a long hospital stay of 6.4–10.5 days [17,18]. Blohme et al. [19] have reported their series of 490 living open donor nephrectomies with a major complication rate of 1.4% and a minor complication rate of 13.6%.

Often the major criticism towards laparoscopic approach has focused on the complications that were supposed to be more frequent than in open nephrectomy. Kavoussi et al. [16] classified the possible complications into needle and trocar injuries, insufflation, dissection and closure injuries, and Gill et al. [15] presented the USA experience and complications rate for laparoscopic nephrectomy. Vascular injuries were the most common lesions and occurred during dissection of the renal hilum or accessory vessels. Complications according to insufflation can lead to cardiopulmonary problems, hypercarbia with associated acidosis and eventually pulmonary gas embolism. Postoperative incisional hernias have been described in trocar sites larger than 10 mm [20,21].

The complications of surgery can be uniformly compared according to the modified classification described Clavien-Dindo [7] (Table 2). We also have found similar overall complication rates for each group (Table 3). It is also notable that the majority of complications in both groups was minor and was similar with other series of open or RPN [15-19,22,23].

5. Conclusions

Currently in the last 10 years, there have been performed more than 1200 cases of retroperitoneoscopic nephrectomies. Based on the results of our study we conclude that RPN should be currently recognized as the method of choice for most kidney diseases requiring nephrectomy. The main “disadvantage” in terms of operation time can be widely compensated by the advantages of less analgesia, reduced hospital stay and cosmetic advantages. The cosmetic appearance and shorter convalescence after such procedures is more attractive to the patient who is quite satisfied with the overall result.

In our experience the durability of operating time mainly depended on learning curve, the individual pathology, i.e. size of the kidney, number of renal arteries, and peri-renal adhesions.