THE COAXIAL PLUGGED RENAL BIOPSY : FIRING THE GUN THE SAFEST WAY

Introduction:

Percutaneous kidney biopsy is the gold standard for obtaining tissue for histopathological and immunohistochemical evaluation for accurate diagnosis of renal parenchymal disease. While the aim of kidney biopsy is to obtain adequate tissue with minimal complications, significant differences exist in the methods from centre to centre. While most centres use noncoaxial technique of biopsy with a trucut needle and an automated gun, we describe our experience of ultrasound guided kidney biopsy at our centre using the coaxial technique followed by plugging of biopsy tract with a metallic coil. To the best of our knowledge, this is one of the largest series describing the use of this technique. 

Methods:

A total of 158 patients underwent percutaneous native kidney biopsy at our center over the last three years. All patients had normal coagulation profile and platelet counts at baseline. Blood thinners were witheld 3-5 days prior to procedure. The procedures were performed  largely on a day care basis. Under standard aseptic precautions and local anesthesia, 18 gauge trocar and cannula was advanced in the renal cortex with a medio-lateral trajectory under real time ultrasound guidance. Once satisfactory position of the needle tip was confirmed, the trocar was replaced by 18 G semiautomated trucut biopsy needle with a throw of 20 mm. Renal cores were obtained under real time ultrasound guidance to avoid capsular puncture . Core quality was confirmed by inspecting the core using magnified photograph with a smart phone. Whenever possible, a wet mount of the core was examined under light microscope to identify glomeruli. A 5mm diameter stainless steel coil was deployed across the biopsy tract after satisfactory cores were obtained. Patient was hemodynamically monitored for 4 hours after the biopsy. A repeat ultrasound evaluation was performed after 1 hour. A low threshold was maintained for doing CT scan and CT angiography in case of suspected perinephric hemorrhage. Emergent catheter angiography and transarterial embolization was done in case of active contrast extravasation on CT angiography. Technical success, minor and major perinephric hemorrhage, need for post biopsy transfusion, need for transarterial embolization, need for admission, intensive care, nephrectomy and death were recorded. Adequacy of biopsy material was confirmed on pathological evaluation. Need for repeat biopsy was also recorded. 

Results:

The procedure was technically successful in all patients and yielded material for histopathological, IHC and electron microscopic evaluation. Cortical tissue was obtained in all the patients. One biopsy was reported as non diagnostic in view of medullary tissue only . Coil plugging of the biopsy tract was technically successful in all patients. 2 patients had significant perinephric hemorrhage which was detected within an hour of the biopsy procedure. CT angiography showed active contrast extravasation suggesting ongoing hemorrhage.Catheter angiography and coil embolization was done in these two patients. Minor perinephric hemorrhage not needing transfusion was observed in 2 patients. None of the patients needed nephrectomy. There were no biopsy related deaths in our series

Conclusions:

Percutaneous plugged renal biopsy with coaxial needle is a highly effective and safe procedure with minimal complications and makes this procedure safe to be done routinely as an outpatient procedure, thus minimising cost  . 

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.