Editing Prostate Biopsy (section)

== Technique ==

=== Equipment ===

* '''Ultrasound machine and biplanar probe'''
**Probe may be configured as side-fire vs. end-fire
***Randomized trials found no significant difference in prostate cancer detection rates between these two approaches[https://pubmed.ncbi.nlm.nih.gov/24725491/]
**'''The best visualization of the biopsy/needle path is in the sagittal plane'''
**Transperineal biopsy cannot be done with an end-fire probe or a side-fire probe with a short linear array[https://pubmed.ncbi.nlm.nih.gov/29409845/]
***Linear array needs to be long enough to visualize from just beyond the perineal skin to the apex of the prostate
* Disposable sheaths to cover the TRUS probes (e.g. condom)
**See [https://www.youtube.com/watch?v=izurJz0qXF4 Video] on preparing TRUS probe with lubrication and condom
*'''18-guage biopsy instrument'''
**The biopsy instrument advances the needle ≈0.5 cm and samples the subsequent ≈1.5 cm of tissue with the tip extending ≈0.5 cm beyond the area sampled. 
***Throw length/penetration depth/stroke length is the total distance the needle travels
***Notch length is the length of the tissue sample
***See Figure 1 in [https://pubmed.ncbi.nlm.nih.gov/30021242/ link]
***Bard Magnum has notch length of 19 mm and stroke length of 22 mm[https://pubmed.ncbi.nlm.nih.gov/30021242/]
**Therefore, when sampling the PZ, the needle tip may be placed 0.5 cm posterior to the prostate capsule before firing; advancing the needle to or through the capsule can result in sampling of more anterior tissue, missing the most common location of cancers.[https://www.us.elsevierhealth.com/campbell-walsh-wein-urology-9780323546423.html]
* '''Local anesthetic'''
**'''1% lidocaine without epinephrine'''
***'''Maximum safe dose: 3mg/kg[https://tam.nhsh.scot/formularies/highland-formulary/anaesthesia/local-anaesthesia/local-anaesthesia/]'''
****Maximum safe dose with epinephrine: 7mg/kg[https://tam.nhsh.scot/formularies/highland-formulary/anaesthesia/local-anaesthesia/local-anaesthesia/]
***1% lidocaine: contains 10 mg of lidocaine per 1 mL
***Maximum anesthetic volume in mL = maximum allowable dose (mg/kg) x (weight in kg/10) x (1/concentration of local anesthetic) = mL
****In 70 kg patient, can give 3 * 70/10 * 1/1 = 21 mL
***'''5 ml per side, is sufficient to provide pain relief[https://pubmed.ncbi.nlm.nih.gov/24725491/]'''
**1% lidocaine without epinephrine mixed with 8.4% sodium bicarbonate[https://pubmed.ncbi.nlm.nih.gov/34048827/]
***Can use up to 20-30cc
* 7 inch 22-guage spinal needle
*10cc syringe
*Ultrasound-specific lubricating gel
*Specimen containers
*Transperineal only
**PrecisionPoint Transperineal Access System
***Comprised of 3 components[https://pubmed.ncbi.nlm.nih.gov/29409845/]
****Clamp/rail subassembly
*****Distal portions of the rails are used to stabilize the assemble against the perineal skin
****Needle carriage with 4 apertures
****15 gauge access needle
*Prepare equipment
**Apply ultrasound-specific lubricating gel inside disposable sheath (e.g. condom)
**Insert probe into disposable sheath
**Apply constriction method so that lubrication jelly stays at tip of probe
**Apply ultrasound-specific lubricating gel over disposable sheath at tip of probe
**For transperineal only
***Assemble PrecisionPoint Transperineal Access System
****Apply Coban Self-Adherent Wrap to probe
****Put sliding carriage with ring over Coban
*****Stop on sliding carriage towards patient
*****Smaller holes of access canula towards patient
****Tighten ring so that sliding carriage aligned at 12 o'clock on ultrasound probe
**Prepare biopsy instrument

=== Anesthesia ===

* '''Approaches[https://pubmed.ncbi.nlm.nih.gov/16439219/]'''
** '''Regional anesthetic'''
***'''Periprostatic nerve block'''
****Nerves can be blocked with either unilateral or bilateral injection, around the apex or base of the gland (in the groove between the gland and seminal vesicles).
****Typically performed using a 7 inch 22-gauge spinal needle, and the biopsy channel of the ultrasound probe
****'''Aspirate the syringe before injecting to ensure that the vascular system has not been entered'''
****'''Method 1[https://pubmed.ncbi.nlm.nih.gov/8558671/][https://pubmed.ncbi.nlm.nih.gov/24725491/]'''
*****'''In the region of the neurovascular bundle at the base of the prostate, just lateral to the junction between the prostate and seminal vesicle'''
****** '''Can be easily identified as a hypoechoic (dark) area on TRUS'''
******See [https://pubmed.ncbi.nlm.nih.gov/8558671/ Figure 2 in link] and [https://www.semanticscholar.org/paper/Pain-during-Transrectal-Ultrasound-Guided-Prostate-Nazir/8c1020245b7d2c8f298441aa0355ffe577cd2fde/figure/3 Figure]
******See [https://www.youtube.com/watch?v=Mo3DO1mFTdU Video]
*****Ultrasound monitoring can confirm separation of the tissue planes caused by injection
*****The injection is performed twice, once either side the midline.
****Method 2 (transrectal)[https://pubmed.ncbi.nlm.nih.gov/16439219/]
*****A position just lateral to the midline, and away form the external sphincter is chosen. The needle is passed through rectal mucosa and local anaesthetic instilled, so that the anaesthetic pools within fascial layers (presumed to the Denonvillers' fascia) and bathes the posterior surface of the gland, from the apex up to the base.
*****The injection is performed twice, once either side of the midline.
****Conflicting evidence if direct infiltration into the prostate (intraprostatic injection) can augment the anesthetic benefit seen with periprostatic injection
***Pudendal nerve block[https://pubmed.ncbi.nlm.nih.gov/31374287/]
****Pudendal nerves are located 2cm lateral to anterior medial edge of anus and 3cm deep to skin
** Topical rectal anesthetic gel
** Variations in probe design
** Glyceryl trinitrate (GTN) paste
** Oral NSAIDs
** Inhaled nitrous oxide
** Intravenous analgesia

=== Transrectal ===

* See videos
**[https://www.youtube.com/watch?v=_DTbRREJsSk&list=PLmlqgyiBVx1EvCpovdviVhpHLlWhov98i&index=56 Transperineal biopsy (UColorado)]
**[https://www.youtube.com/watch?v=0p5aK69r6AI Transperineal biopsy (UMichigan)]
*'''Position: usually left lateral decubitus position with knees and hips flexed 90°; can also be done lithotomy'''
**Lithotomy is preferred for brachytherapy treatment planning or placement of fiducial gold markers for external-beam therapy

*Step by step
**Perform a DRE to (2):
**#Rule out any rectal pathology that would contraindicate insertion of the probe
**#Allow identification of any palpable prostatic abnormalities to which special attention could be paid during ultrasound examination
** Insert the lubricated ultrasound probe slowly and with pressure to dilate the anal sphincter.
** Adjust the gain to provide a uniform mid-gray image of the normal peripheral zone
*** The shading of the peripheral zone should be the homogenous gray standard by which other areas of the prostate are classified as hyperechoic, hypoechoic, or isoechoic.
** Scan the prostate, from the base to the apex
*** Evaluate for any hypoechoic lesions in the prostate
*** Scan in the axial/transverse plane, followed by the sagittal plane
**** Rotate probe counter-clockwise to access right lobe of prostate, and clockwise to access left lobe of prostate
** Measure the prostate size.
*** Measuring the prostate size is recommended prior to infiltration of local anaesthesia[14]
*** The prostate is measured in 3 planes. Typically, in the axial/transverse view, height and width are measured and in the sagittal/lateral view, length is measured
** Perform periprostatic nerve block
** Warn patients that they should expect a loud click when the biopsy gun is fired.
** Take biopsies following appropriate template
*** Use needle guide button on ultrasound machine, if available
*** 12-core
**** Lateral apex, mid, base
**** Medial apex, mid, base
**** The initial biopsy is taken midway between the mid-point of the prostate gland and the lateral margin
**** The probe is then rotated laterally and a subsequent biopsy is taken at the same level but more laterally placed to sample tissue from the anterior horn of the peripheral zone (PZ).
*** Use needle guide button on ultrasound machine, if available
*** It is important to place the biopsy needle correctly at the prostate capsule in order to sample the outer-most part of the PZ.
**** The biopsy needle travels a few millimetres forward of its position on TRUS and a frequent error is the insertion of the biopsy needle into the PZ prostatic tissue which results in the biopsy needle passing further into then gland and not sampling the area close to the capsule which is frequently the site of the PZ cancers.
*** It is important to ensure the biopsy sampling is spatially distributed correctly at the base, mid-gland and apex.
*** Care must be taken not to rebiopsy the same area particularly in smaller prostates as this can give misleading information about the extent of the cancer within the gland.
** Remove ultrasound probe and apply digital pressure to biopsied area to reduce bleeding
**Inform patient of reasons to return to hospital

* 

=== Transperineal ===

* See video accompanying [https://pubmed.ncbi.nlm.nih.gov/31374287/ article]
*See [https://www.youtube.com/watch?v=_DTbRREJsSk&list=PLmlqgyiBVx1EvCpovdviVhpHLlWhov98i&index=57 video]
*Position: usually lithotomy
*Step by step
**Perform a DRE to (2):
**#Rule out any rectal pathology that would contraindicate insertion of the probe
**#Allow identification of any palpable prostatic abnormalities to which special attention could be paid during ultrasound examination
**Secure scrotum anteriorly with tape
**Trim hair, if needed
**Prepare perineum with chlorhexidine 
**Perform pudendal nerve block, if performing without sedation
***Pudendal nerves located 2cm lateral to anterior medial edge of anal canal and 3cm deep to perineal skin
***Mark 2cm lateral to anterior medial edge on each side
***Puncture with needle at each mark and advance 3cm. Infiltrate with local anesthetic (5cc 1% lidocaine without epinephrine)
**Insert the lubricated ultrasound probe slowly and with pressure to dilate the anal sphincter.
***At this point the access needle is not engaged into the skin but rather is positioned several millimeters away from the perineum so that it can be used as an external gauge of the rotational angle of the linear ultrasound array
**Adjust the gain to provide a uniform mid-gray image of the normal peripheral zone
***The shading of the peripheral zone should be the homogenous gray standard by which other areas of the prostate are classified as hyperechoic, hypoechoic, or isoechoic.
**Scan the prostate, from the base to the apex
***Evaluate for any hypoechoic lesions in the prostate
***Scan in the axial/transverse plane, followed by the sagittal plane
****In axial view, right side of prostate will be on left side of screen and left side of prostate will be on right side of screen
****In sagittal view, rotate probe counter-clockwise to view right lobe of prostate, and clockwise to view left lobe of prostate
**Perform perineal skin block with local anesthetic 1cm lateral and 1cm superior to the superior aspect of the anus
***Inject 5cc local anesthetic on each side
**Perform periprostatic nerve block
***Pass spinal needle through access canula through skin marking
***Guide spinal needle towards apex of prostate under ultrasound vision
***Inject local anesthetic in between space of prostate and pelvic floor muscles, and along the track extending from the prostate to the skin
**Measure prostate size, if not done previously
***Measure the prostate in 3 planes.
****Typically, in the axial/transverse view, height and width are measured and in the sagittal/lateral view, length is measured
**Warn patients that they should expect a loud click when the biopsy gun is fired.
**Take biopsies following appropriate template
***Use needle guide button on ultrasound machine, if available
***Choose aperture position on device based on height of the intended area of biopsy and engage access needle into the perineal skin
****No more than 2 aperture positions should be needed to sample prostate
***20 cores (2 cores (different locations) taken from 5 sites on each side) +/- target(s)[https://pubmed.ncbi.nlm.nih.gov/34048827/]
****5 sites
****#Posterior medial
****#Anterior medial
****#Posterior lateral
****#Anterior lateral
****#Base
***3-4 cores from target(s)
**Remove ultrasound probe and apply pressure to perineum to reduce bleeding
**Inform patient of reasons to return to hospital