Percutaneous nephrolithotomy PCNL, which is imaginatively compared to “stone extraction”, is a small hole of the thickness of a pen in the waist, through the skin to the kidney channel, under the direct view of the nephrolithoscope or ureteroscope, with the help of stone extraction or lithotripsy equipment to achieve the removal of stones. Minimally invasive treatment methods. Holmium laser, pneumatic ballistics, and ultrasound are the most commonly used lithotripsy devices. This procedure can be performed in one stage for most PCNL patients, i.e., all stones are removed at the time of fragmentation in one operation.
Percutaneous nephrological technique is a technique to diagnose and treat diseases of the renal pelvis, calyces and upper ureter through percutaneous pelvic access, and is an important part of endoluminal urology.
Compared with open surgery, the advantages of PNL are: stones can be found and crushed and removed under direct vision; stones can be crushed at once and all removed at that time; the operation can be stopped and staged at any time; stones can be treated in conjunction with ESWL; and the damage is less than open surgery and less than repeated ESWL.
Indications
1. All kinds of renal and upper ureteral stones are indications for percutaneous nephrolithoscopy. The following are to be preferred for percutaneous nephrolithoscopy.
1, renal stones larger than 62.5px, especially cast stones.
2, complex renal stones, symptomatic diverticular stones of the calyces, stones of the intrarenal type with combined pelvic junction stenosis, etc.
3, cystine stones, calcium oxalate monohydrate stones for which ESWL is ineffective.
2.Ureteral stenosis in the upper segment or connection.
3.Take foreign bodies from the renal pelvis and upper ureter.
Preoperative preparation
1, clear diagnosis: intravenous urography to understand the structure of the renal pelvis and calyces and choose the most suitable puncture calyces. Retrograde contrast or water imaging if the affected side is not visible.
2. exclude contraindications: those whose systemic function cannot tolerate the procedure and those with bleeding tendency to control stability.
3.Treat urinary tract infection: use sensitive antibiotics for those with preoperative abnormal urinary routine and fever. In case of suspected renal pus accumulation, puncture and drainage first, after control of phase II surgery.
Anesthesia, body position, intraoperative medication
1.Anesthesia: simple nephrostomy can be completed under local anesthesia. stage I PNL, using even epidural anesthesia, can ensure a long operation and facilitate patients to hold their breath to cooperate with the operation. Percutaneous nephrological operation, the patient’s position changes a lot, the lumbar anesthesia plane is unstable, in addition, lumbar anesthesia has a large impact on blood pressure.
2. Position: After anesthesia, the patient is placed in a lithotomy position, and the F5~7 ureteral catheter and ureter are left in place. The role of ureteral catheter is: 1) to inject water to increase the pressure in the renal pelvis to facilitate successful renal puncture; appropriate injection of contrast agent can make the target calyces visible and guide the direction of the puncture needle; 2) to serve as a marker to identify the pelvic ureter; 3) to prevent lithotripsy from entering the ureter during lithotripsy; 4) to facilitate the discharge of lithotripsy from the operating sheath by pressurizing the catheter and injecting water. Renal puncture and operating position: prone position with the abdomen padded.
3. Intraoperative medication: prophylactic use of antibiotics. Give lithotripsy 1 to 2kU to reduce intraoperative bleeding. Give isoproterenol 25mg and dexamethasone 5mg to treat the patient’s chills.
Operation method
The key to PNL is to establish and maintain a reasonable percutaneous nephrostomy access. Microscopic identification of the direction of the renal pelvis, calyces, and ureter is also very important for finding stones. Then, effective lithotripsy methods for stone extraction should be mastered.
1. Selection of the target renal calyces: The selection of the punctured renal calyces should be formulated according to the specific conditions of the stone and the renal pelvis and calyces. Principle: It is best to select the posterior group of the lower renal calyces. After the puncture of the lower calyces, stones in the lower calyces, renal pelvis and middle and upper calyces can be treated; after the puncture of the middle calyces, stones and PUJ stenosis in the middle calyces, renal pelvis, upper and lower calyces and upper ureter can be treated. The path of puncture is from the lateral margin of the kidney in a posterior position into the renal parenchyma and along the axis of the calyces into the calyces. Avoid direct puncture of the renal pelvis without passing through the sinus tract of the renal parenchyma, which is prone to extravasation of perfusate, resulting in displacement of the kidney, alteration of the fistula tract, and operational failure. Postoperatively, urinary cysts are easily formed.
2.Puncture procedure: The skin puncture point is usually chosen to be 10-300 px open next to the spine, 12 ribs below or 11 ribs between the posterior axillary line. The puncture site and direction are first determined under fluoroscopy/B ultrasound. A small incision is made in the skin at the puncture site. After the puncture needle enters the renal peritoneum, it moves up and down with respiration, at which point it advances another 1.5 to 50 px to enter the renal calyces with urine overflow. The guidewire is sent through the puncture needle into the renal calyces, renal pelvis, and ureter. The soft part of the front end of the guidewire should enter the renal pelvis completely. Otherwise, the dilator cannot be properly guided into the renal calyces. The dilator is used to dilate along the guidewire step by step to the desired ductal diameter. The direction of the dilator should be the same as the direction of entry of the puncture needle. The depth of dilator entry should not exceed the depth of puncture needle entry. After dilatation, the operating sheath is placed into the renal calyces.
3.Lithotripsy method: Generally, the stone is broken along the edge of the stone, so that it can be easily broken into pieces and flushed out with the perfusion fluid. After crushing the pelvic portion of the cast stone, the stone can be pushed along the edge of the calyx in the direction of the pelvis, which can move the stone branches of the calyx into the pelvis.
4. Stone extraction method: small crushed stones flow out with the flushing fluid, and larger crushed stones are clamped out with foreign body forceps.
Postoperative treatment
1.General treatment
At the end of the operation, a D-J tube is placed in the fistula in a paralleling fashion and a nephrostomy tube is left in place. If there is a lot of intraoperative bleeding, clamp the fistula tube to facilitate hemostasis. Postoperative bed rest, attention to the presence of excessive blood loss or water absorption, timely treatment and application of antibiotics.
2. Treatment of residual stones
1, residual stones that can be taken through the sinus tract, 5 to 7 days after phase II extraction.
2.Small stones that are not easily retrieved through the sinus tract, ESWL is performed.
3. large residual stones that cannot be easily retrieved through the sinus tract, lithotripsy of the second channel may be performed.
4.Residual cystine and uric acid stones, lithotripsy through fistula.
3. Treatment of the fistula
If the fistula is dislodged within 1 week, it is difficult to put it back and should be re-tubed; if the fistula is dislodged after 1 week, it can often be put back via the original sinus tract at that time.
The fistula can be removed if the patient has no fever, back pain, or urinary extravasation. The fistula is maintained for 3 to 4 days after stage I surgery to achieve hemostasis.
Complications and their management
1. Bleeding: It is a common comorbidity of stage I percutaneous nephrolithoscopy. Intraoperative renal parenchymal bleeding can be controlled by operating sheath compression. If intraoperative bleeding is severe, the procedure should be stopped and compressed with a balloon catheter. More bleeding requires blood transfusion, poorly controlled bleeding requires arteriography, selective renal artery embolization if necessary, or even open surgical exploration.
2, renal pelvis perforation: excessive movement of the instrument can easily cause, can be injected contrast agent clear. Renal pelvis perforation is found to stop surgery immediately, ureteral stent tube and nephrostomy tube are placed, adequate drainage is performed, and stones are treated in phase II.
3. Dilutional hyponatremia: caused by excessive water absorption. Stop surgery, check electrolytes urgently, give hypertonic salt, diuretic, oxygen and other treatments.
4, perirenal pus accumulation: focus on prevention. Pre-operative preparation should be adequate, and post-operative ureteral catheter and nephrostomy tube should be kept open.
5.Proximity organ injury: 11 intercostal puncture may damage the pleura, which can be avoided by using ultrasound-guided puncture. Once the patient is found to have a pneumothorax, immediately stop the operation and treat according to the principles of pneumothorax management. Injury to the intestinal canal, conservative treatment is often effective.