Transperineal Prostate Biopsy in the Office Setting: Anesthetic Considerations

Name: Transperineal Prostate Biopsy in the Office Setting: Anesthetic Considerations
Uploaded: 2025-04-14T15:31:00.000Z
Duration: 54 min 33 s

Transparent Prostate Biopsy Under Local Anesthesia

Introduction to Transparent Prostate Biopsy

The speaker introduces the topic of transparent prostate biopsy performed under local anesthesia in an office setting, utilizing unique technologies like 3D ultrasound and the Precision Point access system.

Audience Engagement

The speaker engages the audience by asking how many are performing transrectal biopsies and how many use local anesthesia, revealing a mixed crowd.

Traditional Transrectal Approach

The traditional method for prostate biopsy has been transrectal since the mid to late 1980s, with most urologists in the U.S. still using this approach.

While easy to visualize and access the prostate, transrectal biopsies pose risks due to needle contact with rectal mucosa, potentially leading to infections from stool and bacteria.

Infection Risks Associated with Transrectal Biopsy

A systematic review by Michael Liss (2017) indicates a 5-7% risk of infection from prostate biopsies, with 1-3% resulting in hospitalization due to sepsis.

In the U.S., approximately 1.97 million prostate biopsies are performed annually; even at a conservative infection rate of 1%, this translates to about 20,000 patients facing complications each year.

Economic Impact of Complications

The economic burden associated with sepsis from these procedures is significant; costs can reach tens of millions annually based on literature estimates.

Alternative: Transparent Prostate Biopsy

An alternative method is transparent prostate biopsy via a percutaneous route that avoids stool contact by passing through skin between scrotum and rectum while still using an ultrasound probe for visualization.

Clinical Evidence Supporting Transparency Method

Literature supports that transparent approaches lead to improved outcomes regarding infectious complications compared to traditional methods.

Randomized Control Trial Findings

A randomized control trial showed zero grade two or above infections in patients undergoing transparent biopsy without antibiotics versus a significant infection rate in those receiving transrectal biopsies with antibiotics.

Logistical Advantages of Transparent Biopsy

The logistical simplicity of not requiring pre-procedure rectal cultures or antibiotic administration enhances patient experience and reduces healthcare burdens.

Technology Utilization

The speaker discusses using the Koellis Trinity platform for conducting these procedures but emphasizes that other systems can also be used effectively.

Overview of Koellis Trinity System

Ultrasound-Guided Prostate Biopsy Techniques

Motorized Ultrasound Probe Functionality

The ultrasound probe features a motorized head that allows for image acquisition without manual rotation, simplifying the procedure.

Images of the prostate are captured in three planes: axial, coronal, and sagittal, enhancing diagnostic accuracy.

Image Segmentation and Fusion Process

Prior to biopsy, segmentation of MRI images is performed either by the urologist or radiologist to identify lesions accurately.

An elastic fusion step aligns ultrasound images with pre-acquired MRI data, allowing for precise targeting during the biopsy.

Needle Placement and 3D Reference Volume Creation

After confirming the target location via updated imaging sweeps, needle placement is executed based on real-time feedback from computer vision technology.

A 3D reference volume is populated with various needle locations throughout the procedure to ensure comprehensive coverage of potential lesions.

Use of Precision Point Transparent Access System

The precision point system enhances access during biopsies through a freehand approach using an access cannula and needle guide.

Urologists can contour lesions themselves rather than relying solely on radiologists, which increases familiarity with patient anatomy and improves outcomes.

Addressing Medical Legal Concerns

Urologists often face pushback regarding liability when contouring images; however, utilizing key images provided by radiologists can mitigate these concerns effectively.

By identifying lesion boundaries through existing key images in PACS systems, urologists can confidently perform their own segmentations.

Practical Implementation of Access Systems

The access system consists of components like a rail clamp assembly that secures to the ultrasound probe for stability during procedures.

A custom 3D printed adapter can be created for better attachment to probes without compromising sterility during procedures.

Nerve Blocks for Prostate Procedures

Anatomy and Nerve Intervention

The pudendal nerve emerges from the alcock canal beneath the ischial tuberosity of the pelvic bones, branching into inferior anal nerves and paranal nerves.

Effective local anesthesia requires blocking peripheral nerves or the trunk of the pudendal nerve to allow patient comfort during procedures involving skin and soft tissue.

Techniques for Anesthesia

The periapical triangle block is commonly used to numb branches of the pudendal nerve, defined by boundaries formed by levator ani muscle complex, external anal sphincter, and rhabdosphincter of urethra.

Under ultrasound guidance, practitioners first numb the skin before targeting a 3D column leading up to the prostate for effective anesthesia on both sides.

Prostate Apex Block

To directly numb the prostate, a prostate apex block is performed after numbing surrounding structures; lidocaine is injected through endopelvic fascia to bathe the prostate effectively.

A combination approach including pudendal nerve block, periapical triangle block, and prostate apex block enhances chances of successful anesthesia during procedures.

Gallagher Solution Preparation

The Gallagher solution consists of diluted buffered lidocaine (0.11%) prepared with lactated ringers and sodium bicarbonate to minimize pain during injection while maintaining physiological pH (7.4) and osmolality (298 mOsm/L).

Buffered lidocaine allows more molecules in non-ionized form ready to cross cell membranes quickly compared to unbuffered solutions that can cause burning upon injection due to their acidic pH (5.5).

Chemistry Behind Lidocaine Efficacy

Lidocaine's effectiveness relies on its ability to pass through bilipid cell membranes; it must be in a non-ionized state for optimal action on voltage-gated sodium channels after crossing these membranes.

Using buffered solutions increases neutral charged lidocaine molecules available for immediate action while reducing discomfort associated with injections at lower pH levels.

Recipe Breakdown for Gallagher Solution

The preparation involves 250 ml lactated ringers, 5 ml of 8.4% sodium bicarbonate, and 15 ml of 2% lidocaine; this results in an effective concentration without irritation or burning during administration due to matching serum conditions.

Local Anesthesia Techniques for Pudendal Nerve Block

Overview of Local Anesthesia Administration

The solution's concentration is reduced to 0.11%, allowing for a larger volume to block the pudendal nerve effectively, resulting in less pain and more potency.

A repeating syringe system is utilized for injecting large volumes, with options available from Boston Scientific and USA Vein Solutions at low costs.

Injection Technique Steps

Initial infiltration targets the skin overlying the ischial tuberosities and areas where the biopsy needle will be engaged. This prepares the site for further procedures.

Bilateral blocking of the pudendal nerves is performed under Doppler ultrasound guidance as they emerge from Alcock's canal, followed by infiltration into subcutaneous tissue and pelvic floor muscles.

Ultrasound Guidance in Procedure

The ultrasound probe identifies key anatomical landmarks such as the ischial tuberosity, aiding in locating arteries and veins during injection. Color Doppler assists in visualizing blood vessels accurately.

Approximately 20 to 30 mL of dilute buffered solution is injected into the nerve sheath while avoiding vascular structures, ensuring safety due to dilution levels. This technique provides a dense nerve block quickly.

Comprehensive Numbing Process

Additional local anesthetic administration occurs at skin puncture sites and within a triangular column around the prostate, using about 150 to 200 mL of lidocaine solution overall for effective numbing before biopsy procedures begin.

Pain scores during this procedure have been reported between 2.5 to 3.5, comparable to transrectal approaches, indicating effectiveness in pain management during biopsies under local anesthesia conditions.

Biopsy Workflow Post-Numbing

After achieving adequate numbness, a reference ultrasound acquisition creates a 3D model of the prostate without moving the probe; this aids in accurate targeting during biopsy procedures.

10 Sector Technique for Prostate Biopsy

Overview of the 10 Sector Technique

The speaker discusses the 10 sector technique for performing a transparent prostate biopsy, popularized by Dr. Aloway at Paranealogic.

This method involves taking 20 core biopsies, dividing the prostate into five sectors on each side to cover the entire peripheral zone and anterior fibromuscular stroma.

Biopsy Core Strategy

For larger prostates, cores are taken from both the apex to mid-gland and then from mid to base, resulting in stacked cores totaling 20.

In smaller prostates, it is possible to perform a 16 core biopsy, which is done about 50% of the time.

Cancer Mapping Insights

The speaker references studies mapping where prostate cancer typically occurs within glands, showing that cancer predominantly affects the peripheral zone while largely sparing the transition zone.

Notably, there are exceptions at the anterior aspect of the prostate's apex; hence, additional cores from this area are included in biopsies.

Imaging and Focal Therapy Applications

After biopsy procedures, images can be exported for a 3D review, allowing precise location tracking of lesions during subsequent treatments like focal therapy.