Comparison of Pericapsular Nerve Group Block versus Fascia Iliaca Compartment Block as Postoperative Pain Management in Hip Fracture Surgeries.

Background and
Objectives: Postoperative pain management and early recovery play an important role in the functional outcome following hip surgeries. Recently, pericapsular nerve group (PENG) block has been used as a good alternative for postoperative pain management following hip fracture surgeries. We compared the efficacy of (PENG) block and fascia iliaca compartment block (FICB) as postoperative pain management in hip surgeries.
Methods: Forty patients of the age group of 18 years and older of American Society of Anesthesiologists Physical Status Classes I and II scheduled for hip fracture were selected and the patients were randomly allocated into two groups. Group A comprised of 20 patients who received PENG block and Group B comprised of 20 patients who received FICB. 30 mL 0.25% Levobupivacaine and 4 mg dexamethasone was given for both blocks. The following outcomes were measured: Total fentanyl consumption in 24 h, dynamic pain during 2, 6, 10, 14, 18, and 24 h, Visual Analog Pain score during 2, 6, 10, 14, 18, and 24 h, quadriceps femoris muscle strength.
Results: Even though there was no significant difference in the duration of analgesia and dynamic pain grades between these blocks, there was notable difference in Visual Analog Pain score and the motor power of quadriceps femoris which indicates the potency of sensory blockade and decrease in motor sparing was significantly seen in PENG block than FICB.
Conclusion: The findings of this study suggest that PENG block was more appropriate analgesic modality than FICB in patients undergoing hip surgeries as postoperative analgesic. Copyright:

INTRODUCTION

Hip surgeries are one of the common procedures in the orthopedic surgeries. Usually, the hip surgeries are done under subarachnoid blocks so the postoperative pain management becomes challenging. Postoperative pain management and early recovery play an important role in the functional outcome following hip surgeries.[1] Lumbar epidurals, fascia iliaca compartment blocks (FICB), and femoral blocks have been used in the past to provide postoperative analgesia.[2] Although these blocks were not sufficient to give complete analgesia, they were also associated with lower extremity weakness which can interfere with the early mobility of the patients.[3] Complete analgesia cannot be achieved by these techniques because of the sparing of articular accessory nerves.[4] Recently, pericapsular nerve group (PENG) block has been used as a good alternative for postoperative pain management following hip fracture surgeries because it blocks obturator nerve, accessory obturator nerve, and femoral nerve which innervates the anterior hip capsule.[5] The aim of this study was to compare the efficacy of (PENG) block and FICB as postoperative pain management in hip fracture surgeries.

METHODS

After institutional ethical committee clearance (SMC/IEC/2020/02/008) and obtaining consent, 40 patients of the age group of 18 years and older of American Society of Anesthesiologists (ASA) Physical Status (PS) Classes I and II who were scheduled for hip fracture (neck of femur, intertrochanteric, and subtrochanteric fracture of femur) surgeries such as dynamic hip screw fixation and proximal femur nailing under spinal anesthesia were selected, and the patients were randomly allocated into two groups by computer generated random allocation. Patients with coagulopathy, infection at the injection site, allergy to local anesthetics, severe cardiopulmonary disease, ASA PS Classes ≥ III, diabetic neuropathies, patients receiving opioids for chronic analgesic therapy, any other contraindication to regional anesthesia, inability to comprehend Visual Analog Scale (VAS), and hip joint arthroplasty were excluded from the study. Group A comprised of 20 patients who received PENG block and Group B comprised of 20 patients who received FICB and they were using block randomization method by using block size of 10. Nerve blocks were done by an independent consultant anesthesiologist not involved in the study. The patient and the investigator were blinded to the study. The flow chart of participants is illustrated in Figure 1.

Figure 1

Flow chart of participants

Spinal anesthesia was performed for all the patients under the sitting position. Under aseptic precautions, subarachnoid blockade was administered using Quincke's needle of size 25 gauge using 0.5% bupivacaine (heavy) around 3–3.5 mL in volume. The level of spinal blockade was assessed after 5 min. The level of sensory block was assessed bilaterally in anterior axillary line by the pin prick method using a 25G needle. Motor block was assessed by movement of the lower limbs using modified Bromage scale:

0 = Able to rise extended legs

1 = Inability to flex the knee

2 = Inability to flex the ankle

3 = Complete block.

Once adequate level was achieved, surgery was initiated.

Intraoperatively, the patient's vitals including heart rate, blood pressure, oxygen saturation, and temperature were monitored and charted. Intravenous fluids were administered adequately according to each patient's requirement. Once the surgery was completed, an experienced anesthetist well trained in the usage of ultrasound guided nerve blocks performed the nerve block using ultrasound machine (logiq e series, GE, USA Inc.). Another anesthetist who was involved in this study loaded the drugs with equal volume (30 mL) in both the groups in 50 mL syringe. A low frequency (3–8 megahertz [MHz]) curvilinear transducer was placed in the transverse plane over the anterior inferior iliac spine and moved over inferiorly to visualize the pubic ramus. The femoral artery and ilio pubic eminence were then visualized. Using in-plane technique, 10 cm echogenic 22G stimuplex needle was advanced from lateral to medial direction, and 30 mL 0.25% levobupivacaine with 4 mg dexamethasone was deposited between the psoas tendon and the superior pubic ramus. A high frequency (7–15 MHz) linear probe was placed perpendicular to the inguinal ligament, between the anterior superior iliac spine and the femoral artery. The probe was moved laterally until the sartorius muscle was identified. Needle was introduced in-plane to the probe from inferior aspect which passed through the fascia iliaca, the fascia was first seen indented by the needle. As the needle pierces the fascia, a pop may be felt. After negative aspiration, 30 mL of 0.25% Levobupivacaine and 4 mg dexamethasone was deposited just below fascia iliaca. All complications such as hypotension, bradycardia, seizures, and local anesthetic toxicity were carefully monitored. After the nerve block, the patient was shifted to postanesthetic care unit (PACU) and monitored for 24 h. In PACU, intravenous patient controlled analgesia (PCA) (CADD-Legacy® PCA Ambulatory Infusion Pump, Model 6300) with fentanyl infusion was started in both the groups and the pump settings was the following: bolus of fentanyl 20 mcg, maximal hourly dose limit of 100 mcg, lockout interval –10 min, no background infusion.

The following outcomes were measured: Total fentanyl consumption in 24 h, Dynamic pain during 2, 6, 10, 14, 18, and 24 h, Visual Analog Pain score during 2, 6, 10, 14, 18 and 24 h, Quadriceps femoris muscle strength, duration of surgery, level of spinal blockade, and duration of analgesia. The total fentanyl consumed by each patient through the intravenous PCA was recorded after 24 h. The dynamic pain score was assessed using the numeric pain rating scale at 2, 6, 10, 14, 18, and 24 h postoperatively which is given in Figure 2. The patients were explained about the scoring system elaborately and asked to grade the number in accordance to their pain relief. In the numeric pain rating, 0 stood for no pain, 5 for moderate pain, and 10 for worst pain.

Figure 2

Numeric rating scale

In a similar way, Visual Analog Scoring System which was a psychometric response scale was used for assessing the extent of pain relief. The patients were provided a chart with the Visual Analog Scale and were asked to pick the image that corresponded to the extent of pain they were experiencing which is given in Figure 3.

Figure 3

Visual analogue score

To know the extent of motor blockade that can happen with PENG and FICB, the power of quadriceps was assessed at 2, 6, 10, 14, 18, and 24 h. The muscle power scale (MRC) was used for this purpose. If there was no contraction of the quadriceps muscle, then the grading was taken as 0, for active movement against gravity the grading was 3 and for normal power 6.

The MRC grading was as follows:

0 = No contraction

1 = Flicker or trace of contraction

2 = Active movement with gravity eliminated

3 = Active movement against gravity

4 = Active movement against gravity and resistance

5 = Normal power.

The sample size for each group to achieve alpha (α) value of 0.05 and power of 80% by calculating the mean and standard deviation of the primary outcome (total fentanyl consumption in 24 h) between the two groups was 12. Hence, we fixed a sample size of 20 in each group. Analysis was done using the SPSS(Statistical Package for the Social Sciences) Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. and the Student's t-test was applied for interpretation of results and P ≤ 0.05 was considered as statistically significant. All the outcome measures are depicted as mean and standard deviation.

RESULTS

The demographic data include age, sex, ASA PS classification, and type of surgery among both the groups were comparable and shown in Table 1. All surgeries were carried out under spinal anesthesia, and the intraoperative period was uneventful in both the groups. The following outcomes were measured: Total fentanyl consumption in 24 h, Dynamic pain during 2, 6, 10, 14, 18, and 24 h, visual analog pain score during 2, 6, 10, 14, 18 and 24 h, Quadriceps femoris muscle strength, duration of surgery. dynamic pain, and visual analog score comparison are shown in Tables 2 and 3. The independent t-test result shows that there was no significant difference in dynamic pain. We can find the notable difference in Visual Analog Pain score and the motor power of quadriceps femoris muscle strength, which states that the increase in the potency of sensory blockage and decrease in the motor sparing seen in the PENG block than the FICB.

Table 1

Demographic Data

Variables	Group A N (20)	Group B (N=20)
Age	53.9±9.9	52.5±9.8
Sex
Male	10	12
Female	10	08
ASA
I	09	07
II	11	13
Type of surgery
DHS	08	07
IT	07	06
ST	05	07

ASA - American society of Anesthesiologists, DHS – Dynamic hip screw, ST - Subtrochanteric fracture, IT - Intertrochanteric fracture

Table 2

Dynamic pain between Group A and Group B

Dynamic pain	Group A (Mean±SD)	Group B (Mean±SD)	t	P
2 Hours	0.60±0.940	0.85±0.933	-0.844	0.404
6 hours	1.40±0.681	1.65±8.489	0.267	0.791
10 hours	1.40±0.598	1.45±0.510	-0.284	0.778
14 hours	1.45±0.605	1.80±0.834	-1.520	0.137
18 hours	1.45±0.510	1.30±0.470	0.967	0.340
24 hours	1.65±0.813	1.25±0.639	1.731	0.092

SD: Standard deviation

Table 3

Visual analog score between group A and Group B

Visual analog score	Group A (Mean±SD)	Group B (Mean±SD)	t	P
2 Hours	0.6±1.231	1.05±1.395	-1.082	0.286
6 hours	1.85±0.988	1.55±1.05	0.93	0.358
10 hours	1.85±0.988	1.6±0.598	0.968	0.339
14 hours	2.10±0.718	1.6±5 0.671	2.048	0.048
18 hours	2.00±0.725	1.4±0 0.598	2.854	0.007
24 hours	2.10±0.788	1.30±0.571	3.676	0.001

SD: Standard deviation

The independent t-test result shows that there was a significant difference in Visual Analog Score at 14 h (P = 0.048), at 18 h (P = 0.007), and at 24 h (P = 0.001). The independent t-test result shows that there was a significant difference in motor power after 18 h and 24 h (P = 0.009 and P = 0.005, respectively) which is shown in Table 4. Total fentanyl consumption after 24 h in PENG group (213 ± 20.2 mcg) and in FICB group (255 ± 32.3 mcg) showed a significant difference which is illustrated in Figure 4.

Table 4

Motor power between Group A and Group B

Motor power	Group A (Mean±SD)	Group B (Mean±SD)	t	P
2 Hours	1.25±0.716	0.85±0.92	1.823	0.076
6 hours	2.4±1.095	1.85±1.309	1.441	0.158
10 hours	3.3±0.979	3.05±1.234	0.710	0.482
14 hours	4.15±0.875	3.55±0.999	2.021	0.05
18 hours	4.85±0.366	4.25±0.91	2.734	0.009
24 hours	5±0	4.6±0.598	2.990	0.005

SD: Standard deviation

Figure 4

Scatterplot of total fentanyl consumption after 24 h between Group A and Group B

DISCUSSION

PENG block is a novel peripheral nerve block used for postoperative analgesia for hip surgeries. In this the local anesthetic deposited in the musculofascial plane between the Psoas muscle and the superior pubic ramus blocks the articular branches of femoral nerve, obturator nerve, and accessory obturator nerve supplying the anterior hip capsule.[5] It provides good pain relief at rest as well as during the movement such as sitting upright and side to side movement of the affected limb. FICB is considered as other alternative to the femoral and lumbar plexus blocks which were routinely practiced for providing postoperative analgesia following hip surgery.[6] Cooper et al. states that ultrasound-guided femoral nerve blocks are equal to ultrasound-guided fascia iliaca blocks for fractured neck of femur.[7] In the review of current practices of peripheral nerve blocks for hip fracture and surgery, Kukreja et al. have described supra inguinal FICB to be effective in providing analgesia. Although FICB provides analgesia for hip surgeries, it does not block the accessory obturator nerve and there can be associated weakness of quadriceps muscles which affects the early mobilization after surgery.

Recent trends in pain management protocols following hip surgeries have shifted toward effective analgesia with limited motor involvement. Given the excellent analgesic effect, FICB is a commonly used modality as part of postoperative pain control regimens of hip surgeries. However, it may reduce quadriceps strength, which is essential for early mobilization and is associated with an increased risk of postoperative falls. The relationship of the articular branches from these three nerves to the inferomedial acetabulum and the space between the anterior inferior iliac spine and iliopubic eminence may prompt for adequate analgesic cover.[8] Thus, PENG block has emerged as a reasonable alternative to FICB that produces a predominantly sensory block with greater quadriceps strength preservation. In addition, it provided excellent pain relief around the hip joint and preserved motor strength with minimal differences from baseline.

With reference to pain relief, with both blocks we find in our study, there was no significant difference in dynamic pain during 2, 6, 10, 14, 18, and 24 h after block in both the groups. There was a significant difference in Visual Analog Score at 14, 18, and 24 h. Previous study on retrospective case series of PENG block for hip arthroplasty primary versus revision by Kukreja et al. showed median reduction of pain scores in their study was 7 points, in primary compared to revision.[5] The study population was very small and was confined to only hip arthroplasty. In our study which included orthopedic surgeries (neck of femur, intertrochanteric, and subtrochanteric fracture of femur), there was a median reduction of pain score at 14, 18, and 24 h. In another meta-analysis by Hong and Ma including 11 trials and 937 patients compared pain scores at different intervals with placebo after FICB.[6] In FICB group, the reduction in VAS score at 1–8, 12, and 24 h were 1.03, 1.06, and 1.14 with standard mean difference (SMD), respectively. In our study, SMD of FICB group was 1.6, 1.4, and 1.3, respectively, and was comparable. However, significant VAS scores were seen with PENG group SMD of −0.008, respectively, which was statistically significant.

Ueshima and Otake shows the benefits of the PENG block are patient positioning for the procedure, no significant motor weakness, potential motor sparing effect, and analgesic efficacy block for hip surgery.[9] Guay et al. state that all peripheral nerve blocks are supplement to general anesthesia which gives early mobilization after hip surgeries.[10] Birnbaum et al. state that blocking sensory nerves such as obturator nerve, accessory obturator nerve, and femoral nerve which innervates the anterior hip capsule will adequately cover analgesic part of hip surgeries.[1112] In our study, there was a significant difference in motor power between Group A and B after 18 h. Total fentanyl consumption after 24 h in PENG group (213 ± 20.2 mcg) and in FICB group (255 ± 32.3 mcg) showed a significant difference. Kukreja et al. compared oral morphine equivalent (OME) average postoperative opioid use in the first 24 h was 78.7 OMEs in the revision group, compared to 18.4 OMEs in the primary group.[5] In our study, total consumption of fentanyl was less in Group A than the Group B. Thus, the study shows that there was better analgesic coverage among Group A PENG than the Group B FICB and there was sparing in muscle weakness in Group A than Group B which enable the early mobilization of the patients after hip surgeries.

CONCLUSION

The findings of this study suggest that PENG block was a better analgesic modality than FICB in patients undergoing hip surgeries.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.