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PENG block

Advantages of out-of-plane approach

Lopez-Lopez, David; Reza, Pablo Casas; Vazquez, Maria Gestal; Garcia, Paula Dieguez

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Indian Journal of Anaesthesia: July 2021 - Volume 65 - Issue 7 - p 563-564
doi: 10.4103/ija.IJA_146_21
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We have read with interest the article 'Pericapsular nerve group (PENG) block: A feasibility study of landmark based technique,' by Jadon et al.[1] We want to congratulate them, as feasibility and safety of a landmark technique will contribute to a widespread use of this block[2] in situations of low ultrasound availability. They performed 4 of 10 blocks under ultrasound guidance in an out-of-plane approach, leading to optimal analgesia. According to our experience,[3] several advantages arise with this approach.

Some precautions should be considered in pericapsular nerve group (PENG) block. Proximity to the femoral vessels and nerve should preclude to medial-to-lateral injection. The tip of the needle should not be placed in the medial aspect of the psoas tendon due to the proximity of urinary viscera or obturator nerve.[4] Lateral femoral cutaneous nerve injury should also be avoided,[5] as it is usually located close to the prick point. An out-of-plane technique would minimise the chance of unintentional harm, as the prick is given more medial and needle tip is directed to an outer zone of iliac bony edge.

A preliminary scan can easily discard anatomical abnormalities, minimising the chance of unintentional damage, as the whole path of needle cannot be seen with this approach. It could also be a better alternative when high-quality ultrasound equipment is unavailable, as the identification of the whole needle is not necessary.

PENG block efficacy was corroborated by our group using an 'in-plane' approach, showing less opioid consumption after total hip replacement. Based on our recent experience, we suggest an 'out-of-plane' approach as a quicker and potentially safer alternative.

PENG block was performed in 38 patients. Approach was chosen according to the preference of the anaesthetist. We measured the time needed to block performance, including preliminary scan, and morphine consumption. No neurologic or vascular damage was detected [Table 1].

Table 1
Table 1:
Statistical data

Several disadvantages should be considered. Out-of-plane blocks are usually difficult in unexperienced hands and catheter placement could be more difficult.

To sum up, 'out-of-plane' approach [Figure 1] carries benefits like a quicker technique. It could also be a safer choice, although further studies are needed to determine it.

Figure 1
Figure 1:
Out-of-plane PENG block scheme (a). Out-of-plane PENG block: sonographic image (b and c). (1) Pectineus muscle, (2) inguinal ligament, (3) femoral vein, (4) femoral artery, (5) iliopectineal bursa, (6) iliopectineal eminence, (7) psoas tendon, (8) femoral nerve, (9) genitofemoral nerve, (10) anteroinferior iliac spine and (11) lateral femoral cutaneous nerve. Arrows in (b): needle tip. Arrow in (c): needle trajectory

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Conflicts of interest

There are no conflicts of interest.


1. Jadon A, Sinha N, Chakraborty S, Singh B, Agrawal A. Pericapsular nerve group (PENG) block: A feasibility study of landmark based technique Indian J Anaesth. 2020;64:710–3
2. Girón-Arango L, Peng PW, Chin KJ, Brull R, Perlas A. Pericapsular nerve group (PENG) block for hip fracture Reg Anesth Pain Med. 2018;43:859–63
3. Casas Reza P, Diéguez García P, Gestal Vázquez M, Sampayo Rodríguez L, López Álvarez S. Pericapsular nerve group block for hip surgery Minerva Anestesiol. 2020;86:463–5
4. Tran J, Agur A, Peng P. Is pericapsular nerve group (PENG) block a true pericapsular block? Reg Anesth Pain Med. 2019;44:257
5. Girón-Arango L, Roqués V, Peng P. Reply to Dr Roy et al.: Total postoperative analgesia for hip surgeries: PENG block with LFCN block Reg Anesth Pain Med. 2019;44:684–5
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