Tips to Enter the Pelvicalyceal System in the Supine Position

Tip 2

Set up an adequate armamentarium before the procedure

In general, a variety of scopes (semirigid and flexible ureteroscopes, rigid and flexible nephroscopes of different sizes), accessories (ureteral access sheaths, double J stents, nephrostomies,…), lithotripsy devices (pneumatic/ultrasonic combined lithotripter, holmium laser lithotripter) and other materials (guidewires, contrast medium, …) should be prepared and preliminary checked. In particular, for the renal access an adequate armamentarium should be at disposal (Table 46.2).

Table 46.2

Preparation of the armamentarium before the percutaneous procedure

In terms of diversity	In terms of quantity	In terms of functioning
18 Gauge Chiba needle Hydrophilic guidewires Scalpel Fascial dilators Semirigid serial Amplatz dilators Metallic telescopic Alken dilators Balloon dilators of different diameters Amplatz sheaths of different sizes and lengths	At least two of each element needed, if fundamental (in case of damage or accidental loss of sterility)	Foolproof preliminary control that all the armamentarium is not only present in the operating room, but that it works correctly (C-arm, fluoroscopic screen, ultrasound machine, the complete series of serial/progressive dilators, …)
		before receiving the patient in the operating room

Tip 3

Bear in mind few basic rules to avoid the well-known complications (Table 46.3)

Table 46.3

How to avoid complications

Bleeding:	Infections:
Remember renal vascularization (the Brodel’s avascular line/arterial distribution within the parenchyma/less vascularized areas) Reach the tip of the chosen papilla following the axis of the calyceal infundibulum Avoid inadvertent overadvancement of the dilators or of the Amplatz sheath Avoid insufficient insertion of the dilators or of the Amplatz sheath Avoid excessive torqueing/inclination of the instruments during the procedure	Negative preoperative urine culture Stop procedure if purulent urine comes out from the needle Keep low intrarenal pressures during the procedure Avoid retrograde and/or pressurized irrigation in absence of adequate drainage Be sure that the Amplatz sheath is in place Use operating instruments 4F smaller than the Amplatz sheath Use heated irrigation (excluding shivers due to hypothermia, in case of fever)
Damage of the collecting system:	Lesion of neighbouring organs:
Remember the spatial orientation of the kidney in all planes Superior poles are more medial and posterior Lateral margins are more posterior Avoid transpyelic or transinfundibular punctures Avoid inadvertent overadvancement of the dilators or of the Amplatz sheath Avoid excessive torqueing/inclination of the instruments during the procedure	Remember the topographic anatomy in the supine and supine-modified positions Draw the anatomical landmarks to respect (see Tip 4) Check on preoperative CT for retrorenal colon, hepato/splenomegaly, variations in the anatomic relationships due to congenital renal malformations, skeletal deformities, previous surgeries, very high or very low BMI Check with ultrasound for interposed viscera

Tip 4

Correctly position the patient, and adapt the position to the current requirements

Place the patient in the Galdakao-modified supine Valdivia (GMSV) position:
- put the patient supine,
- elevate the flank to operate with jelly pillows (or rolled towels, or a 5-l saline bag, or an inflatable pillow),
- arrange the ipsilateral leg on a padded stirrup extended, with the ankle in axis with the body, and fix it,
- arrange the contralateral leg on a padded stirrup well abducted and flexed and fix it,
- bend the ipsilateral arm on the thorax on an adequate support (we use towels) and fix it,
- moderately abduct the contralateral arm for venous access and pressure control (Fig. 46.1a,b).
  
  Figure 46.1
  
  (a) Patient in the classical GMSV position; (b) Obese patient in the GMSV position; (c) 20-month-old boy in the GMSV position with a modified arrangement of the lower limbs
Mark the reference lines to be respected during the puncture:
- the anterior limit is the posterior axillary line (which should be drawn in advance, with the patient standing),
- the cranial limit is the 12th rib,
- the caudal limit is the iliac crest,
- the posterior natural limit is the lateral margin of the paravertebral muscles (Fig. 46.1a).
Adapt the described position to the patient’s requirements:
- in very thin patients, or in those with mild forms of retrorenal colon, or in case an upper calyceal access is needed, the elevation of the flank should be increased, obtaining a more oblique position of the patient, so that the puncture can be performed closer to the paravertebral muscles;
- in obese patients the fat falls on the side opposite to the treated one (Fig. 46.1b), and might be fixed and flattened applying adhesive strips of Tensoplast, thus reducing skin-to-stone distance [3, 10]
- children may avoid the classical lithotomic position with padded stirrups for the lower limbs; a simple and stable retrograde access may be sufficient (Fig. 46.1c);
- particular care should be taken when positioning a patient with skeletal deformities, adapting it in different ways from time to time, and paying particular attention to avoid pressure damages during the procedure.

Tip 5

Be able to adapt technical choices to intraoperative conditions

The issue of the intraoperative versatility is an essential feature of any modern PNL, in agreement with the principles of personalized medicine and tailored therapies which are currently the standard of modern healthcare. Preliminary retrograde ureteroscopy is the main tool we have in order to contextualize each step of PNL, and to adapt the procedure to the patient and not vice versa (see Tip 5) (Table 46.4).

Table 46.4

Algorythm useful in order to adapt technical choices to intraoperative conditions

The Puncture of the Collecting System

Tip 1

Choice of the calyx for the access

preliminarily choose the best access calyx in view of PNL, based upon the features of the urolithiasis to treat, the relationships between tract and neighboring organs, the pelvicalyceal anatomy. This is the reason why urologists should always establish renal access by themselves, instead of relying on radiologists [19]. Usually our preference goes to an inferior one in most cases, to be reached subcostally, and a posterior one, easily allowing access to the anterior ones;
there are particular cases that would require a middle or upper calyceal access, but that might also be adequately managed with flexible scopes and the contribution of the retrograde access in the supine position, using a single inferior calyceal access;
if a superior calyceal access is absolutely needed, the anesthetist may contribute reducing the respiratory movements, and even inducing apnea in maximal inspiration, in order to facilitate it. The renal displacement technique [15] may also be of help: initially a lower or middle calyx is punctured with an 18-Gauge needle; then the proximal end of the needle is progressively pushed in the cephalic direction, consequently pushing the kidney caudally by a lever maneuver. In this way the kidney is many millimeters lower and the upper pole calyx is more accessible for the puncture.

Tip 2

Ultrasound guidance (Fig. 46.2)

Figure 46.2

(a) Before starting the procedure preliminary ultrasound (US) is useful, in order to check the absence of visceral interposition along the needle path, assess the target of the puncture, and identify with the inclination of the US probe the inclination of the puncturing needle. (b) Remember the inclination of the needle by heart, maintaining the same point of entry of the needle, and perform the puncture under biplanar fluoroscopic control only. (c) Alternatively, integrate fluoroscopic puncture with freehand US. (d) The inclination of the needle after an inferior calyceal puncture successfully performed at the first attempt is the same as in b

Tip 3

Fluoroscopic guidance

when the access needle is put under the C-arm over the body of the patient for the preliminary biplanar identification of the exact target of the puncture (Fig. 46.2c), remember that in the supine position the X-ray incidence is nearly perpendicular to the orientation of the access needle, and not oblique forming an acute angle as in the prone position. This circumstance simplifies the renal puncture, and allows the surgeon to avoid to work during the whole procedure with the hands under the fluoroscopic beam;
when retrograde pyelography is performed in the supine position the posterior calyces turn out to be darker than the anterior ones, because due to gravity the contrast medium fills them more and earlier; on the contrary and for the same reason, in the prone position the posterior calyces are filled later and appear paler than the anterior ones;
insert the needle under fluoroscopic control, maintaining the same point of entry of the needle and the same inclination previously identified by US; if urine doesn’t come out check with US and delicately move up and down the needle under fluoroscopic control: the consensual movement of the papilla of the calyx filled by the contrast medium will help to understand the missing distance between tip of the needle and target calyx. In any case, the needle should enter into the calyx only for a short tract, without overpassing it;
if fluoroscopic-only guidance is used in the supine position, the identification of the third dimension without the aid of US is also possible, exploiting the cephalad 30° tilting of the C-arm [12]. A reference clamp is placed on the abdominal wall in the vertical projection of the target calyx and the needle is advanced towards the calyx. If no urine comes out from the needle, the C-arm is tilted 30° cranially. If the distance between needle and reference clamp increases this means that the needle is under the calyx, on the contrary, if needle and clamp become nearer this means that the needle is above it. In any case the needle should be repositioned accordingly. The three-finger technique [18] can also be applied with the patient in the supine positions.