Introduction
Elderly people are quite prone to hip fractures because of age related osteoporosis and other degenerative changes.1 The surgical reduction and fixation of the fractures are the only definitive treatment in most patients.2 Opioids and various other drugs are used to relieve the associated pain prior to the surgery but the related adverse effects like nausea, vomiting, respiratory depression, hypotension, and delirium preclude their much use.3 Femoral Nerve Block (FNB) and Fascia Iliaca Block (FIB), are used for achieving effective perioperative analgesia because of their opioid-sparing effects4, 5 but the analgesic effect of these blockades is only moderate as the obturator nerve (ON) is not adequately affected.6 The anterior hip capsule is the richly innervated by ON, accessory obturator nerve (AON) and femoral nerve (FN). The high articular branches from FN and AON are consistently found between the anterior inferior iliac spine (AIIS) and the ilio-pubic eminence (IPE), whereas the ON is located close to the infero-medial acetabulum. The pericapsular nerve group (PENG) block is an ultrasound guided approach,7 which blocks these articular branches of FN, ON, AON and is found to be very effective as a regional anaesthesia technique for hip fracture surgeries. Few studies have demonstrated its beneficial effects in reducing the pain during the procedures. A recent case series on the use of PENG block found that 9 out of 10 patients did not require any support while making them upright for spinal anaesthesia (SA).8 There is a considerable scope and evidence to increase its application and thus we hereby report the use of USG-guided PENG block by using 0.25% bupivacaine (20ml) in 4 patients.
Case Series
The PENG block was performed in 4 patients scheduled to undergo hip fracture orthopaedic surgery under spinal anaesthesia. All the patients were explained about the procedure during the pre-anaesthetic visit one day prior to the surgery and informed written consent was taken. Patients were informed about the verbal analogue score (VAS) for pain assessment ranging from 0 to 10, with 0 being “no pain” and 10 being “the worst pain imaginable.” Standard hospital protocol regarding medical optimisation, intravenous line placement, pre-medication, and antibiotic prophylaxis were followed. In the operating room, monitors for non-invasive blood pressure, 5-leads continuous electrocardiogram, and pulse oximeter were attached. The sono-anatomy of the hip was analysed in the supine position, by using a low frequency curvilinear probe (3–5 Hz) to view AIIS, IPE, and pubic ramus (PR) and a pulsating femoral artery (FA) above the iliacus muscle. After all aseptic precautions, under local anaesthesia, PENG block was given with 23G spinal needle connected to de-aired extension tubing with 10-ml syringe using in-plane approach. A total of 20ml of local anaesthetic drugs (bupivacaine 0.25%) was given after hydro-dissection and negative aspiration.
The pain assessment before the block at both resting and dynamic position (15-degree leg raise test) was done utilizing VAS score. The pain assessment in both the positions was repeated after 20 minutes after the block.
The ease of sitting for the conduct of regional anaesthesia was graded as: 0-not satisfactory, 1-satisfactory, 2-good and 3-optimal.
The demographic profile of the patients is tabulated below. (Table 1)
Table 1
Demographic profile of the patients
The pain scores at rest at T0 (before the block) were 8,7,8,6 (on a scale of 0-10) in patients 1,2,3 and 4 respectively. (Figure 1) The dynamic pain scores (assessed at 15-degree leg raise) were 10 in all the patients prior to the procedure. (Figure 1)
After the institution of block the pain of all the patients reduced considerably. At 20 minutes after the block the pain scores at rest were at the level of 0,0,0,2 in case 1,2,3 and 4 respectively. The dynamic scores also fell quite significantly in three patients to level of 1 while one patient had moderate improvement as he rated the pain scores at 4 (Figure 2).
The patients could sit upright comfortably during the institution of spinal anaesthesia as their pain component was considerably reduced. When asked to grade the ease of sitting for spinal anaesthesia, three patients rated 3 and one patient rated it as 1 (Figure 3).
Discussion
There are only a few studies, most of them being case reports or small series which have demonstrated the application of PENG block in decreasing the pain and helping in the positioning of patients for spinal anaesthesia. Giron-Arango et al7 in a retrospective cohort of 5 patients demonstrated a decrease of 7 points in median pain scores. They used 20 ml of 0.25% bupivacaine with epinephrine (1:400,000) in 4 cases & 20 ml of 0.5% ropicacaine with epinephrine (1:200,000) plus dexamethasone 4mg in one of the case. Acharya et al8 also inferred that PENG block is an extremely useful approach for hip surgeries by using 20 ml of 0.125% bupivacaine in 10 of their patients. NRS pain scores were 6-9 (pre-block) vs 3 in three, 2 in four and 1 in three patients after the block. 9 out of 10 patients sat upright at the time of institution of sub-arachnoid block. Jadon et al9 demonstrated a decrease in pain scores by using 20 ml of 0.25% bupivacaine in 10 patients. NRS pain scores at rest were 6 (pre-block) vs 2 (post block) while scores at 150 leg raise were 8 (pre-block) vs 3(post block). There was also significant ease of positioning during spinal anaesthesia. Talawar et al10 (by using 10ml of 0.5% bupivacaine with 10ml of 2% lignocaine-adrenaline) demonstrated the absence of sensation in anterior, medial and lateral compartments of gluteal region in one of their patient undergoing hip arthroscopy. Sahoo et al11 demonstrated a significant decrease in VAS pain scores both at rest and at 150 leg raise position after the PENG block (Pre-block VAS at rest: 7.45±1.53; Post block (30 mins) VAS at rest: 1.1±1.07) (Pre-block VAS at 15◦ passive SLR:9.45±0.75 Post procedure VAS at 15° passive SLR (30 min): 2.35±1.34). Ease of patient positioning for spinal anaesthesia also improved (0-3): 2.65±0.67. Pagano et al12 also (20 ml of mepivacaine 1% and 0.5% ropivacaine) demonstrated a median reduction of pain (NRS) up to 4 points at rest and 6 points in dynamic state in 6 patients. Brown et al13 in a prospective series of 28 patients demonstrated a median reduction in pre-operative to post-operative pain of 7 points (range 3-10) on VNRS. There was also decrease in post-operative opioid use and improvement in patient satisfaction scores. Ueshima et al14 used 10 ml of 1% lignocaine for repositioning of hip dislocation occurring as a complication of hip surgery in 2 of their patients and reported a reduction in pain scores in both the patients (from 10/10 to 3/10 in one case).
The present series also demonstrated a reduction in the pain scores both at rest and at 15-degree leg raise in 4 patients by using 20 ml of 0.25% bupivacaine in PENG block. Pre-block scores at rest were 8,7,8,6 (in patients 1,2,3 and 4 respectively) and at 15-degree leg raise were 10 in all the patients. After the institution of block the pain of all the patients reduced considerably. Post block NRS pain scores after 20 minutes at rest were at the level of 0,0,0,2 (in patients 1,2,3 and 4 respectively) and dynamic scores also fell quite significantly. All the patients could sit upright comfortably during the institution of spinal anaesthesia (ease of sitting for spinal anaesthesia in three patients rated as 3 and one patient rated as 1).
Conclusion
This case series may help to reflect a new and alternative technique of nerve blockade for patients supposed to undergo hip fracture surgery. Still, more randomized controlled trials are required to establish the efficacy, safety, and advantages of PENG block over other regional analgesic techniques and to ascertain the optimal volume/dose and type of local anaesthetics and adjuvant drugs used.