Combined PENG and LFCN blocks for postoperative analgesia in hip surgery-A case report.

Total hip arthroplasty (THA) is considered an extremely painful procedure. Postoperative analgesic technique especially in an elderly with significant comorbidities is even more challenging. Pericapsular nerve group (PENG) block is a novel technique that has been described recently as an effective analgesic method for hip surgery. We report a case of a successful PENG and lateral femoral cutaneous nerve blocks for postoperative analgesia in THA. Copyright:

Hip joint is richly innervated, and the pain following THA is particularly severe. Effective postoperative analgesic technique especially in an elderly with significant comorbidities is challenging.[12]

The use of multimodal analgesia (MMA) emphasizing COX-2 selective NSAIDs and acetaminophen with regional analgesia, including nerve blocks and periarticular infiltration techniques is associated with decreased postoperative use of opioids, and improved outcome in terms of reduced morbidity and reduced length of hospital stay. The objective of the present report is to describe the analgesic technique in an elderly with significant comorbidities undergoing THA.[3]

Case Report

A 65-year old male, ASA IV, scheduled to undergo unilateral primary THA. His medical history includes several comorbidities such as systemic lupus erythematosus, hypothyroidism, chronic kidney disease, hypertension, ischemic heart disease, history of atrial flutter and deep vein thrombosis. ECG showed first-degree AV block, left anterior fascicular block and anterolateral infarct. Echocardiography showed ejection fraction 15 per cent, mitral and tricuspid regurgitation and pulmonary hypertension. Medication list included statin, concor, lasix, allopurinol, hydralazine, isosorbid, levothyroxine, hydroxychloroquine and warfarin that was substituted by enoxaparin five days preoperatively. The patient was evaluated and signed the informed consent to undergo THA under general anesthesia and pericapsular nerve group (PENG) with LFCN block. Standard monitors were attached, and insertion of arterial line was established. Induction of anesthesia was achieved with IV etomidate 0.3 mg/kg, fentanyl 2.5 mcg/kg and tracheal intubation was facilitated with cisatracurium 0.15 mg/kg. Anesthesia was maintained with 1 MAC sevoflurane in 40 per cent oxygen/air. With patient in supine position and after taking all aseptic precautions, an US curvilinear probe (2-5 MHz) was positioned at the anterior superior iliac spine ASIS. The probe was moved slightly caudal to visualize the following structures: the femoral artery, iliopsoas muscle superficially and anterior inferior iliac spine with the iliopubic eminence deep [Figure 1].

Figure 1

Cross-sectional sonographic view at the level of the anterior inferior iliac spine AIIS. Note: White bold line represents block needle advanced to contact iliopubic eminence IPE, FA: femoral artery

A 22 G, 120 mm insulated Needle (Sonoplex Stim, Pajunk, Germany) was inserted in-plane from the lateral side of the probe. Under US guidance, the needle was advanced till its tip in contact with the iliopubic eminence [Figure 1], 30 ml of bupivacaine 0.25 per cent was injected carefully after negative aspiration.

LFCN block was performed using linear US probe (6–15 MHz), the probe positioned caudal to ASIS to visualize the LFCN between sartorius muscle, tensor fascia lata muscle and covered by the fascia lata [Figure 2]. A 22 g, 50 mm block needle was inserted in plain, and 5 ml bupivacaine 0.25 per cent was injected.

Figure 2

Cross-sectional image 2 cm caudal to anterior superior iliac spine. Notes: Arrow points at the lateral femoral cutaneous nerve. Sam: Sartorius muscle, TFLm: Tensor fascia lata muscle

The surgery lasted 140 min, blood loss was 500 ml. A total of 1500 ml of ringer lactate was given. The patient remained hemodynamically stable throughout the surgery. After recovery from anesthesia, the patient was shifted to intensive care unit (ICU) for close monitoring. In the ICU, patient remained hemodynamically stable and pain was assessed by ICU team using numeric rating scale (NRS). Patient did not receive additional analgesics apart from the scheduled acetaminophen 8 mg/kg every 8 h (acetaminophen dose was adjusted by ICU physician). The NRS scored (0 at rest for 24 hours postoperative) and NRS (2 at rest, 3 at movement at 36 and 48 h postoperative).

Discussion

Patient-controlled analgesia using opioids (IV-PCA) is a widely used as an effective method of controlling pain after THA. This method is associated with serious side effects especially in elderly with significant cardiac and renal dysfunction.[3] First described by Giron et al., PENG block is a novel US-guided technique in which LA is deposited between iliopsoas muscle and the iliopubic eminence.[4] LA spreads are demonstrated by cadaveric study to cover the femoral, obturator and accessory obturator nerves.[5] PENG block was described originally as analgesic modality for hip fracture, our report describe the use of PENG block together with LFCN block as adjunctive to cover the lateral surgical incision for THA. Roy et al. in a letter to editor, described the value of adding LFCN block to cover the dermatomal pain in five THA cases.[6] Girone et al. in response to the letter supported LFCN blocking with their original PENG block technique and recommended LA injection beneath fascia lata as the needle withdrawn, and without change needle position after completion PENG block.[7] However, visualization of the LFCN or fascia lata may be difficult with curvilinear US probe used to perform PENG block. To date, there is no recommendation of the optimal LA dose for use in PENG block. We use LA volume of 30 ml in an attempt to achieve more coverage and enhance analgesic efficacy.

In conclusion, PENG block performed with LFCN block may be effective in providing reliable postoperative analgesia for THA. It could be a reasonable alternative to more advanced blocks such as neuraxial and lumbar plexus blocks.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.