penile block

8/12/2019 Penile Block

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Penile Block


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Penile block has been widely used for circumcision. Complications includeinadequate block or, rarely, ischaemia. Techniques vary from injectionbelow the symphysis pubis to ring block of the shaft.

The anatomy related to penile block is one of the least understood areasby anaesthetists. The key points are:

The triangular space lying deep to the fascia, bounded above by thesymphysis pubis and below by the corpora cavernosa.

The fact that the fascia splits on its deep surface to form a verticalsuspensory ligament of the penis which, in turn, divides to encircle theshaft of the penis.

The dorsal nerves and vessels lie deep to the suspensory ligament where itdivides on the corpora cavernosa and are therefore in an enclosed spacewhere they could be depressed if a large haematoma developed.

There are pear shaped, potential spaces on either side of the suspensoryligament which usually do not communicate directly (only 6% do).


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The safest technique is to inject an adequatevolume of local anaesthetic bilaterally deep tothe fascia into the pear shaped spaces on eachside of the suspensory ligament. This avoids mid-

line injection and therefore potential damage tothe dorsal vessels and provides the maximumchance of diffusion into the nerves to block them.Injecting an adequate volume of local anaesthetic

(estimated in children at 1ml + 0.1ml/kg on eachside) should ensure that the ventral branch is alsoblocked so that a satisfactory block is achieved.


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Figure 1. A lateral view of the penis in sagittalsection showing the triangular space boundedby symphysis pubis, the membranous layer of

superficial fascia and the corpus cavernosum.The needle should be inserted to hit thesymphysis pubis (1) and then directed below itthrough the fascia into the space (2) where

the local anaesthetic is deposited to block thedorsal nerves of the penis. X-X shows thesection shown in Figure 2.


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Figure 2. A transverse section through the triangularspace shown in Figure I (X-X). This shows themembranous layer of superficial fascia and thesuspensory ligament of the penis which divides to form

another triangular space fusing with Buck's fasciathrough which pass the dorsal nerves, arteries andveins. The site of insertion of the needle is shownpassing through the membranous layer of superficialfascia. The bilateral injections into the potential spaces

shown allow the local anaesthetic to diffuse into thespace with the nerves with minimal chance of damageto the dorsal nerves, arteries and veins


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This block is useful for circumcision and provides somepost operative analgesia. It avoids potential problemsof caudal anaesthesia for circumcision such as legweakness or difficulty with micturition.

Bupivacaine or lignocaine are widely used for thisblock. It is vital that adrenaline containing solutions arenever used, as severe arterial vasoconstriction can beproduced causing ischaemia or necrosis of the penis.

Bupivacaine may provide excellent post operativeanalgesia for up to 6 hours.

penile block

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