Fig. 32.1
Transverse section of penis
Fig. 32.2
VHVS and MRI images of anatomical structures surrounding the dorsal nerve of the penis; (a) anterior view, (b) sagittal view, (c) transverse view
From the base of the penis, the dorsal nerves divide several times and encircle the shaft of the penis before reaching the glans penis.
The two dorsal nerves are usually blocked separately due to an often present anteroposterior septum (fundiform ligament) at the level of the suspensory ligament of the penis, which divides the subpubic space into two compartments.
Two fascia envelop the penis; the superficial fascia of the penis, a continuation from the superficial fascia of the abdomen, and the deep layer (Buck’s fascia), surrounding all three cavernous bodies, and which is continuous with Scarpa’s fascia.
The subpubic space is bordered anteriorly by the skin, subcutaneous tissue, the superficial fascia, and deep (Scarpa’s) fascia of the abdomen. It is also bounded cranially by the pubis and caudally by the crura of corpora cavernosa.
32.2 Landmark-Based Technique (Subpubic Approach)
32.2.1 Patient Positioning
The patient lies in the supine position.
32.2.2 Landmarks and Surface Anatomy
Pubic symphysis
Inferior border of the pubic rami
32.2.3 Needle Insertion
Two marks are made on the lateral side of the pubic symphysis, just below each pubic ramus (0.5 cm for babies and 1 cm for older boys).
With the penis held downward, the needle is inserted at the puncture site in a slight medial and caudal direction (10–15° to the vertical axis in both directions).
A “pop” is felt as the needle penetrates Scarpa’s fascia, approximately 8–30 mm below the skin (depth does not correlate with patient age or weight). A “pop” may also be felt as the needle passes through the superficial fascia (Fig. 32.3).
Fig. 32.3
Needle insertion through Scarpa’s fascia into the subpubic space
Short-beveled 23G needles, 30 mm in length, are generally used for penile block.
The dorsal penile block provides good analgesia, but may not block the ventral penis sufficiently, especially the frenulum. A ring block around the base of the penis [1] can ensure more effective coverage, especially when used in combination with the dorsal penile block. Ring block has been shown to be more effective than dorsal penile block or topical anesthetic for circumcision in neonates [2].
The ring block can be performed with the same cutaneous puncture site as the dorsal block. The needle can be fanned out subcutaneously to the 3 and 9 o’clock position and then repositioned to these positions to administer subcutaneous local anesthetic through the 6 o’clock/scrotal area (see Fig. 32.4).
Fig. 32.4
Ring block of the penis. The needle is initially positioned dorsally and fanned out to the 3 o’clock and 9 o’clock positions while injecting local anesthetic. The needle is then repositioned to the 3 o’clock and 9 o’clock positions to ensure local anesthetic spread to the 6 o’clock/scrotal areaRelated posts:
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