Pericapsular nerve group (PENG) block for hip fractures: Another weapon in the armamentarium of anesthesiologists.

Dear Editor,

We had been routinely doing either fascia iliaca compartment block (FICB) or femoral nerve block (FNB) in hip fractures with good result.[1] After the claimed analgesic efficacy of pericapsular nerve group (PENG) block, we decided to evaluate this block in our patients.[2] After informed written consent, we performed ultrasound (US)-guided PENG block in 9 patients posted for hip fracture surgery [Table 1]. All patients received PENG block in the preoperative area. Pre-block visual analogue scale (VAS) score at rest, and with 15° passive straight leg-raise (SLR) were recorded.

Table 1

Demographic data

Total number of patients (n)	9
Age (in years)
Median	67
IQR	62.5-77.5
Gender
Male (%)	6 (66.66)
Female (%)	3 (33.33)
ASA-PS (n)
II	2 (22.22%)
III	7 (77.77%)
Fracture Type
NOF	4
NOF with IT	3
IT	2
Procedure Type
Hemiarthroplasty (%),	4 (44.44)
Femur Nailing (%)	5 (55.55)

IQR=Interquartile range, ASA-PS=American Society of Anesthesiologists’- physical status, NOF=neck of femur, IT=intertrochanteric

Standard monitoring (non-invasive blood pressure, pulse oximetry and ECG) was used. A curvilinear probe (2–5 MHz Vivid iq, GE Healthcare) was first placed at anterior superior iliac spine (ASIS) in transverse plane, and then moved caudally to identify anterior inferior iliac spine (AIIS). Then the probe was rotated to align AIIS and iliopubic eminence (IPE) [Figure 1a]. After iliopsoas tendon (IPT) and muscle were revealed together with femoral vessels superficially, 21 G 100 mm echogenic needle (Ultraplex®360, B Braun Melsungen, Germany) was inserted in-plane from lateral to medial and the tip was kept at the midpoint of AIIS and IPE, deep to the psoas tendon. Initially hydrolocation was deployed with normal saline to lift psoas tendon, and then, 20 ml of 0.25% bupivacaine with 4 mg dexamethasone was injected in 5 ml aliquots after negative aspiration [Figure 1b]. Local anesthetic (LA) spread was appreciated with lifting of IPT and medial spread [Figure 1c]. Then, VAS at rest and passive movement (15° SLR) was measured 30 min later. Subsequently, patients were taken to OT for spinal anesthesia (SA) [10–12 mg of hyperbaric 0.5% bupivacaine heavy in sitting position]. We also documented the ease of sitting for conduct of SA which was graded as: 0- not satisfactory, 1- satisfactory, 2- good, 3- optimal. At 24 h post-block, we also took patients' feedback on this block: 1- good, if necessary, will not hesitate for repeat block in future; 2- bad, will never opt for it. Duration of the surgery lasted between 70 and 90 min. All patients received intravenous (IV) paracetamol 1 gm towards the end of the surgery and 8th hourly thereafter along with IV tramadol 50 mg if VAS ≥5. None of the patients needed any additional analgesics in the PACU as VAS was 0 in the immediate postoperative period.

Figure 1

(a) Figure showing position of the hip, probe orientation, and needle insertion. (b) Figure shows sonoanatomy of the block with needle (marked with white arrow) insertion from lateral to medial. Tip is below the psoas tendon (marked with asterix). FN- Femoral nerve, FA- Femoral artery, AIIS- Anterior inferior iliac spine, IPE- Iliopubic eminence. (c) Local anaesthetic (LA) spread just below the psoas tendon and further medially

VAS was assessed before and after block (both rest and movement), 6 h, 12 h, and 24 h postoperatively [Table 2]. Five out of 9 patients reported no pain (VAS 0) at rest and 4 reported VAS 1. Similarly, with dynamic movement, 1 patient reported no pain whereas rest described their VAS 1 to 2. At 24 h, highest pain score reported was 4 (by 4 patients), whereas 4 patients reported VAS 3 and 1 patient described VAS 1. The highest VAS was reported even during turning around in the bed and flexion of hip. However, none of the patients were mobilized in the first 24 h. Anesthesiologist performing SA reported that sitting position provided for SA was optimal, good and satisfactory in 56%, 22% and 22% patients, respectively.

Table 2

Visual Analogue Pain (VAS) score at various points (expressed as mean±SD)

VAS score at various points	Mean±SD
Pre-procedure VAS at rest	6.77±1.20
Pre-procedure VAS at 15° passive SLR	9.22±0.83
Post-procedure VAS at rest (30 min)	0.44±0.52
Post-procedure VAS at 15° passive SLR	1.44±0.72
Ease of Patient Positioning for Spinal (0-3)	2.33±0.86
Postoperative VAS scores
6 h	0.88±0.78
12 h	2.55±0.72
24 h	3.22±0.97

SD=standard deviation, SLR=straight leg raising

PENG block is a musculofascial plane block between psoas tendon and pubic ramus targeting the articular branches of FN and accessory obturator nerve (AON).[2] Later, the same authors found that dye stains not only the articular branches of FN, AON but also obturator nerve (ON); thus, blocking all 3 sensory nerves innervating the anterior hip joint.[3] After the initial description, other authors had found similar analgesic benefit in hip arthroscopy.[4]

Unlike FICB and FNB, PENG block targets the pain carrying articular branches and this eliminates the risk of motor weakness produced by FICB and FNB. Girón-Arango et al. found median drop of 7 points in pain score following the PENG block.[2] We also noticed similar reduction in pain score in our series of patients. Although Yu et al. reported 2 cases of quadriceps weakness following PENG block we did not notice any side effects.[5]

There is a need to compare a case control study or comparative study between PENG and FICB to see analgesic benefit, ambulation, hospital stay and patient comfort in positioning for SA.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.