Ultrasound View of Intraneural Injection

Major signs

Minor signs

Needle inside the nerve

Pop sign

Impalement sign

Halo around the nerve

Increased nerve area

Swelling

View of epineurial sheath

Reduced elastic area

Proximal diffusion

Distal diffusion

Intraneural injection diagnosis is the presence of more than one major sign or a major sign with the presence of two or more minor signs.

Other clinical signs that indicate a probable intraneural injection are:

Persistent paresthesia before injection
Paresthesia or clinical symptoms during injection (harm or cold during injection)
Motor response in a low-current intensity
Fast-onset block

These clinical signs may be considered minor signs of intraneural injection (Figs. 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 13.10, 13.11, 13.12, 13.13, 13.14, 13.15, 13.16, 13.17, 13.18, 13.19, 13.20, and 13.21).

Fig. 13.1

Needle inside the nerve. CP common peroneal nerve, T tibial nerve, Sc sciatic nerve

Fig. 13.2

Needle inside the nerve. U ulnar nerve

Fig. 13.3

Subgluteal sciatic nerve block before injection (a) and after injection (b) showing swelling and increase in the cross sectional area. CP common peroneal nerve, T tibial nerve, Sc sciatic nerve

Fig. 13.4

Intraneural needle (a–c), fascicle spacing (b), swelling (d), increased area (b), and elastic retraction (b–d). H humeral artery, M median nerve

Fig. 13.5

Standard view (ulnar nerve) (a), intraneural needle (b), swelling (c), increased area (c), and distal diffusion (d). U ulnar nerve

Fig. 13.6

Ultrasound guided interscalen brachial plexus block at the level of sixth cervical root (a, b). Intraneural needle position in upper trunk (between C5 and C6) (c) and posterior area increase of the upper trunk (d). Red dashed line indicate the position of the needle. UT upper trunk, C5 fifth cervical root, C6 sixth cervical root, C7 seventh cervical root

Fig. 13.7

Ultrasound guided ulnar nerve block (a) ulnar nerve piercing (b) and posterior area increase (c, d) and swelling (d). Red dashed line indicate the position of the needle. U ulnar nerve, UA ulnar artery

Fig. 13.8

Needle inside the median nerve (b) and swelling/area increase (c). Red dashed line indicate the position of the needle. M median nerve, HA Humeral artery

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