Introduction:

  • Renal biopsies are essential for diagnosing various renal conditions, including generalized parenchymal diseases like glomerulonephritis and nephrotic syndrome, as well as focal lesions such as renal tumors.
  • While non-imaging-guided (blind) biopsies are still performed by some clinicians, evidence suggests that imaging-guided techniques are superior in terms of safety and diagnostic accuracy.
  • Studies have shown that ultrasound (US)-guided biopsies result in fewer complications and better diagnostic yields compared to blind techniques.

Indications:

  • Glomerulonephritis.
  • Nephrotic syndrome.
  • Renal tumors

Contraindications:

  • Abnormal clotting or coagulopathy.
  • Thrombocytopenia.

Pre-procedure Evaluation:

  • Type and screen.
  • Obtain and review labs including clotting profiles and platelet counts.
  • Correct any coagulopathy or other abnormalities before proceeding.
  • Ensure a pathologist is available to assess the specimens for diagnosis.

Equipment:

  • Biopsy Needles:
  • Semi-automated needles (18-G Temno):
    • Advantages: Semi-automated needles provide more control over the biopsy process, allowing the operator to manually advance the needle in stages. This can be particularly useful in cases where precision is crucial, such as when targeting small or difficult-to-reach lesions. The manual control also allows for better tissue preservation, which can be important for certain types of pathological analyses.
  • Fully automated needles (18-G Maxcore):
    • Advantages: Fully automated needles are designed to rapidly and efficiently collect tissue samples with a single trigger action. This can reduce the overall procedure time and potentially minimize patient discomfort. Additionally, the quick action of the needle may decrease the risk of complications such as needle displacement during the biopsy, which can occur if the patient moves or breathes deeply.
  • Coaxial and Non-coaxial Techniques:
    • Coaxial Technique: This involves using a guiding outer needle and a smaller inner needle for sample collection. The coaxial technique is advantageous in oncological cases where multiple samples are needed, as it reduces the need for multiple needle passes, thereby minimizing trauma and the risk of complications.
    • Non-coaxial Technique: In cases where fewer samples are required or where the lesion is easily accessible, a non-coaxial technique may be used. This simpler approach can be less time-consuming and may suffice when only a single or limited number of tissue cores are needed.
  • Imaging Equipment:​ High-resolution ultrasound machine for guidance. Occasionally cone-beam CT may be required for focal lesions.
  • Coaxial Biopsy System (for multiple samples or oncological cases): Guiding outer needle and coaxial needle for multiple sample collection and tract embolization.
  • Hemostatic Material:​ Materials such as Gelfoam® for tract embolization to minimize bleeding risk. Rarely required. unless active hemorrhage through coaxial needle.

Procedure:

Imaging guidance selection:
  • Choose the imaging modality based on the lesion's characteristics and the radiologist's preference.
  • For focal lesions, select a path that avoids crossing the peritoneal cavity, preferably through the retroperitoneal space to minimize the risk of tumor seeding or hemorrhage.
Sterile Preparation:
  • Sterilize and drape the area where the biopsy will be performed.
Local Anesthesia:
  • Administer local anesthetic (e.g., lidocaine) to the skin, subcutaneous tissue, and the renal capsule to ensure patient comfort.
Imaging-Guided Needle Insertion:
  • For native kidneys, the biopsy is typically performed on the left kidney, with the patient placed prone. This involves passing the needle through a significant amount of muscle tissue. The lower pole approach is preferred to avoid vascular structures and the medulla. Usually 2-3 2 cm cores from an 18G needle are sufficient. The pathologist in the room assesses for sample adequacy.
  • For transplant kidneys, the biopsy is performed at the site of the transplant, which is usually more superficial, making it easier to access. However, there is an increased risk of bleeding. A flatter lateral approach is often used in transplant biopsies due to the superficial position of the kidney.
  • ​For generalized parenchymal disease, Insert the biopsy needle into the renal cortex, avoiding trauma to the capsule. The needle should puncture through the capsule without excessive manipulation to minimize the risk of hemorrhage.
  • For focal renal lesions, target the tumor, avoiding the central necrotic area for a representative sample. Avoid traumatizing the capsule; samples should be taken from the cortex (in cases of diffuse disease) or from the tumor. Trauma to the capsule increases the risk of post-procedural hemorrhage. Ensure the needle path stays clear of the colon, using a laterodorsal approach with a steep or shallow angle as needed.
  • For oncological biopsies, use a coaxial technique to minimize the risk of tumor seeding and allow for multiple samples.
  • Samples: Typically, two samples are collected, but sometimes three may be taken depending on the pathologist’s assessment.​
Hemostasis:
  • If using the coaxial technique, hemostatic material such as Gelfoam® can be injected into the biopsy tract to reduce the risk of post-procedural bleeding.
Post-procedure Imaging:
  • Immediate post-procedure utlrasound can detect hematoma or active hemorrhage. In case of active hemorrhage, apply compression until hemostasis achieved or consider embolizing tract if  a coaxial needle is in place. 
  • If concern for persistent hemorrhage or significant drop in hematocrit, consider performing a follow-up ultrasound. 
Post-procedure Care:
  • Monitor the patient’s vital signs after the procedure, especially looking for signs of hemorrhage.
  • Educate the patient about the possibility of minor hematuria, which is common and typically does not require intervention.
  • If a pneumothorax or significant hemorrhage is suspected, obtain appropriate imaging, and intervene as needed.
Patient Discharge:
  • Renal biopsies are generally safe and can often be performed on an outpatient basis in patients without significant comorbidities. 
  • Provide the patient with discharge instructions, including signs of complications to watch for and when to seek medical attention.

Figure:

Ultrasound-guided core needle biopsy of a native kidney. A. Color Doppler shows relatively decreased vascularity of the lower pole. B. The arrow shows a sample being obtained from the renal cortex.

Complications:

Major Complications:
  • Hemorrhage, which may require radiological intervention.
  • Development of an arteriovenous fistula.
Minor Complications:
  • Minor hematuria, not commonly seen and usually requires no intervention.
Post-biopsy Considerations:
  • Absence of a perinephric hematoma post-biopsy typically indicates an uncomplicated procedure.
  • Presence of a perinephric hematoma is not necessarily predictive of a clinically significant outcome but should be monitored.

References:

  1. Maya ID, Maddela P, Barker J, Allon M. Percutaneous renal biopsy: comparison of blind and real-time ultrasound- guided technique. Semin Dial. 2007;20(4): 355–8.
  2. Roebuck DJ. Genitourinary intervention in children. Pediatr Radiol. 2011;41(1):17–26.
  3. Vujanic GM, Kelsey A, Mitchell C, Shannon RS, Gornall P. The role of biopsy in the diagnosis of renal tumors of childhood: results of the UKCCSG Wilms tumor study 3. Med Pediatr Oncol. 2003;40(1): 18–22.
  4. Sebire NJ, Roebuck DJ. Pathological diagnosis of pediatric tumours from image-guided needle core biopsies: a systematic review. Pediatr Radiol. 2006; 36(5):426–31.
  5. See TC, Thompson BC, Howie AJ, et al. Transjugular renal biopsy: our experience and technical considerations. Cardiovasc Intervent Radiol. 2008;31(5): 906–18.
  6. Riccabona M, Schwinger W, Ring E. Arteriovenous fistula after renal biopsy in children. J Ultrasound Med. 1998;17(8):505–8.
  7. Hergesell O, Felten H, Andrassy K, Kuhn K, Ritz E. Safety of ultrasound-guided percutaneous renal biopsy-retrospective analysis of 1090 consecutive cases. Nephrol Dial Transplant. 1998;13(4):975–7.
  8. Sinha MD, Lewis MA, Bradbury MG, Webb NJ. Percutaneous real-time ultrasound-guided renal biopsy by automated biopsy gun in children: safety and complications. J Nephrol. 2006;19(1):41–4.
  9. Ishikawa E, Nomura S, Hamaguchi T, et al. Ultrasonography as a predictor of overt bleeding after renal biopsy. Clin Exp Nephrol. 2009;13(4):325–31.
  10. Waldo B, Korbet SM, Freimanis MG, Lewis EJ. The value of post-biopsy ultrasound in predicting complications after percutaneous renal biopsy of native kidneys. Nephrol Dial Transplant. 2009;24(8): 2433–9.
  11. Novellas S, Chevallier P, Motamedi JP, Kurzenne JY, Berard E, Bruneton JN. Superselective embolization of a post-biopsy renal pseudoaneurysm in a 13-monthold infant. Pediatr Radiol. 2006;36(8):874–6.
  12. Pappas P, Constantinides C, Leonardou P, et al. Biopsy-related hemorrhage of renal allografts treated by percutaneous superselective segmental renal artery embolization. Transplant Proc. 2006;38(5):1375–8.
  13. Al MA, Al-Akash S. Safety of percutaneous renal biopsy as an outpatient procedure in pediatric patients. Ann Saudi Med. 2006;26(4):303–5.
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