Transperineal Prostate Biopsy

Figure 29.1
Extended lithotomy position with buttocks taped above the scrotum to stretch the perineum


After the introduction of lidocaine gel or lidocaine/prilocaine cream (EMLA®) into the rectum (to minimize the probe discomfort) a transrectal ultrasound (TRUS) of the prostate is performed with an endorectal biplanar linear array ultrasound probe: the prostate gland echographic feature is studied and the prostate diameters (anteroposterior height; transverse width; cephalocaudal length) are measured. A prostate gland projection is drawn on the perineal skin, based on the prostate ultrasound measures taken. Four different skin entry points (two posterior and two anterior on the prostate projection) are marked on the two sides of the mid vertical line, about 2 and 3 cm above the anus (taking also into account the estimated distance between the posterior prostate capsule and the anterior rectal wall) (Fig. 29.2). This is a useful tool especially during training.


Figure 29.2
Prostate shape projection with marked skin entry points

Local Anesthesia

Under the guidance of TRUS, local anesthesia of the skin, perineum and the periprostatic nerves is performed. Mepivacaine 2 % (5–7 ml per side) is injected using a 22-Gauge spinal needle inserted through the four skin entry points described above (Fig. 29.3). Local anesthesia is performed both anteriorly and posteriorly.


Figure 29.3
Anterior and posterior peri-prostatic local anesthesia

Biopsy Technique

A 18-Gauge biopsy needle is inserted through the perineal skin, under TRUS guidance. The standard setting for the first biopsy provides a minimum of 18 systematic cores taken from the peripheral posterior zone (PZ) and the anterior zone (AZ) (Fig. 29.4). The standard biopsy scheme includes: (1) six cores from each side of the PZ, from paramedian to lateral, accessing the gland via the posterior skin entry points, for a total of twelve cores; (2) three cores from each side of the AZ, paramedian to lateral, using the anterior skin entry points, for a total of six cores. Transitional zone (TZ) sampling (two cores from each side of the TZ) is performed only for patients with previous negative biopsies. Once in the perineum, the needle is navigated medially or laterally under strict TRUS guidance to reach the prostate. It is important to hold the needle always parallel to the probe (Fig. 29.5) in order to monitor its progression into the perineum. The needle should be directed to the prostate area to be sampled immediately after passing the skin. Moreover, the needle should not be bent during the sampling because it could affect the prostate cores length and quality.


Figure 29.4
TPB scheme seen on TRUS performed according to our internal policies


Figure 29.5
Proper movement of the needle and the probe: parallel and simultaneous

Post-biopsy Procedures

After the biopsy the perineal skin is compressed for hemostatic purposes and a medicated plaster is applied. Any signs of urethrorragia are investigated. A digital rectal examination is performed to exclude a massive hematoma. Each specimen is sent in a separate histology pot fixed in 10 % formaldehyde. On completion of the procedure, the patients are asked to mobilize and are required to pass urine twice. If there are no severe signs or symptoms (severe pain, dizziness, severe hematuria, urinary retention) the patients are discharged some hours after the biopsy.

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Nov 21, 2017 | Posted by in UROLOGY | Comments Off on Transperineal Prostate Biopsy

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