Renal biopsy

Renal biopsy is a crucial tool in the diagnosis of medical disease of the kidney. Histologic information is pivotal in making treatment decisions and providing prognostic information. Ultrasound-guided percutaneous needle biopsy is the current standard for obtaining renal tissue. It has the advantage of being performed with use of local anesthesia in an outpatient setting. Unfortunately, there is up to a 5% rate of significant hemorrhagic complications.

In instances in which percutaneous biopsy has failed or is considered to pose a high risk, patients are traditionally referred for open renal biopsy. This procedure has the advantage of obtaining hemostasis and plentiful cortical tissue under direct vision. However, open renal biopsy has the associated morbidity of an incision and general anesthesia. Laparoscopic renal biopsy combines the advantages of open biopsy with the decreased morbidity of a one- or two-port outpatient procedure. General anesthesia is still required.

Indications and contraindications

The indication for renal biopsy is suspected renal disease, the treatment of which would be influenced by the results of histopathologic tissue analysis. The indications for directly visualized renal biopsy include three categories: failed percutaneous needle biopsy, difficult anatomy, and high risk for bleeding complications.

Anatomic factors that may make a patient unsuitable for percutaneous biopsy include morbid obesity, multiple bilateral cysts, and a body habitus that makes positioning impossible. The risk of hemorrhagic complication may outweigh the advantages of percutaneous biopsy in patients who are receiving long-term anticoagulation, have coexistent coagulopathy, or refuse blood transfusion under any circumstance. Laparoscopic renal biopsy is contraindicated in patients with uncorrected coagulopathy, uncontrolled hypertension, or the inability to tolerate general anesthesia.

Patient preoperative evaluation and preparation

Patients undergo routine screening history, physical examination, and blood analyses, including a complete blood count, basic metabolic panel, coagulation panel, and blood typing with antibody screening. Any problems are evaluated and corrected to the extent possible as determined by the urgency of the biopsy. In addition, patients must be told to refrain from taking aspirin, nonsteroidal anti-inflammatory drugs, and anticoagulants for 5 to 10 days before their procedure. Patients with bleeding disorders need two to four units of packed red blood cells crossmatched and available before the start of the procedure. Patients on long-term anticoagulation are managed in concert with their primary physician, nephrologist, or cardiologist. Cessation before the procedure and continuation thereafter is dependent on clinical necessity.

Patients with thrombocytopenia, which is common in several renal diseases, can receive platelets 30 minutes before incision to boost their platelet count to greater than 50,000 cells/mm 3 . Further platelet transfusion is not necessary in the absence of symptomatic bleeding. Uremic patients may benefit from desmopressin acetate treatment to improve platelet function.

Operating room configuration and patient positioning

The surgeon and assistant both stand at the patient’s back. Place the video monitor in front of the patient. Position the scrub nurse or technician in front of the patient, caudad to the monitor ( Fig. 20.1 ). In addition to standard laparoscopic equipment, required tools include an optical trocar (Visiport [Covidien, Norwalk, CT]; Optiview [Ethicon Endo-Surgery, Cincinnati, OH]; or Kii Optical Separator [Applied Medical, Rancho Santa Margarita, CA]), 5-mm two-tooth laparoscopic biopsy forceps, argon beam coagulator, and oxidized regenerated cellulose (Surgicel [Johnson & Johnson, Arlington, TX]).

Fig. 20.1

The surgeon stands behind the patient, and a single video monitor is placed in front of the patient. The scrub nurse or technician is located in front of the patient caudad to the monitor.

Place the patient on the operating table in the supine position, then apply antiembolism stockings and sequential compression devices. Induce general endotracheal anesthesia, then place an orogastric tube and a urethral catheter. Give 1–2 g of cefazolin for antimicrobial prophylaxis.

The choice of which kidney should undergo biopsy is primarily based on patient-specific anatomic considerations. In addition, a right-sided procedure may be more comfortable for right-handed surgeons, whereas biopsy of the left kidney may involve better working angles owing to its higher position. The technique is essentially the same regardless of side.

After inducing anesthesia, carefully roll the patient into the full-flank position with the umbilicus over the table break. Fully flex the table to increase the space between the iliac crest and the costal margin. Carefully support the head with the headrest, folded sheets, and a head support ring. Align the cervical spine with the thoracic and lumbar spine. Place an axillary roll just below the axilla, and gently extend the arms. Pad the lower elbow with egg crate foam, and place several pillows between the arms.

Securely tape the upper body and arms to the table in position using 3-inch cloth adhesive tape. Use egg crate foam to protect the skin, upper elbow, and nipples from direct contact with the tape. Some skin contact is occasionally necessary to adequately stabilize the patient.

Flex the lower leg at the hip and knee and pad under the ankle. Leave the upper leg straight and separate it from the lower leg with one or two pillows. Place a standard safety strap around the legs and table at a level just below the knees. Securely tape the pelvis in position with more cloth tape, using a towel or egg crate foam over the genitalia for protection. Place grounding pads for electrocautery and the argon beam coagulator on the exposed upper thigh. Prepare and drape the patient in standard surgical fashion ( Figs. 20.2 and 20.3 ).

Fig. 20.2

A , The patient is placed into a full-flank position with the umbilicus over the table break. The table is fully flexed to increase the space between the iliac crest and the costal margin. In addition, the kidney rest may be raised as needed. The head is carefully supported with the headrest, folded sheets, and a head support ring. The lower elbow should be padded with egg crate foam, and several pillows are placed between the arms. The chest, pelvis, thigh, lower leg, and arms are securely taped with 3-inch cloth adhesive tape. B , The cervical spine should be aligned with the thoracic and lumbar spine. An axillary roll is placed just below the axilla, and the arms are gently extended.

Fig. 20.3

Patient positioned for laparoscopic renal biopsy.

Trocar placement

Two-site approach

Retroperitoneal access is identical for right- and left-sided procedures. Mark the skin midway between the iliac crest and the tip of the 12th rib roughly in the posterior axillary line ( Fig. 20.4 ). Make a 10-mm transverse incision in the skin and use a small, curved hemostat to spread the skin and subcutaneous fat. Place a zero-degree lens focused on the blade of an optical trocar in the incision. Holding the optical trocar perpendicular to the skin and aiming approximately 10 degrees anteriorly, repeatedly fire the blade under direct vision until the retroperitoneum is entered. This requires traversing subcutaneous fat and either the lumbodorsal fascia or the flank musculature (external and internal obliques and the transversus abdominis) ( Fig. 20.5 ). Straying too far anteriorly can result in peritoneal entry or colon injury, whereas posteriorly the quadratus or psoas muscles can be damaged, resulting in excessive bleeding.

Aug 8, 2022 | Posted by in UROLOGY | Comments Off on Renal biopsy

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