Sacral erector spinae plane block(S-ESPB) has been recently described. Case reports are showing that it is useful in various types of surgery. In case presentations, it has been reported as effective in providing analgesia in the posterior branches of the sacral nerves in pilonidal sinus surgery, in the treatment of radicular pain at the L5 - S1 level, after a sex reassignment operation and hypospadias surgery, and its use in combination with lumbar ESPB for analgesia was reported after hip prosthesis surgery . Described in 2018, pericapsular nerve group (PENG) block selectively targets the articular branches of the femoral and accessory obturator nerves thereby providing potential motorsparing analgesia for hip surgery

. Recent studies found that PENG block targets the articular branches of the femoral and accessory obturator nerves, only anesthetizes the anterior hip joint sparing posterior part , as well as there was a motor impairment after block which is from local anesthetic (LA) diffusion to the femoral nerve

. Motor-sparing regional anesthesia techniques have emerged as a safer alternative, balancing effective pain relief with the preservation of quadriceps function . These techniques align with Enhanced Recovery After Surgery (ERAS) protocols, which emphasize multimodal pain control, opioid minimization, and early mobility to reduce complications such as venous thromboembolism (VTE) and postoperative pneumonia

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Study design This double-blinded, prospective, randomized comparative study will be conducted in Fayoum University hospital after the approval of local Institutional Ethics Committee and local institutional review board. Written informed consent will be obtained from all patients for these scientific contributions before recruitment and randomization.

Randomization, Allocation Concealment and blinding Patients will be randomly allocated into one of 2 parallel groups (40 in each group) based on sample size. Randomization will be achieved using computer-generated random numbering of each study patient. Allocation concealment will be insured using Sequentially Numbered, Opaque, Sealed Envelopes (SNOSE), prepared by a researcher not involved in patient recruitment or outcome assessment. The block tray and necessary equipment will be prepared by an independent anesthesiologist not involved in patient assessment. The patient and researcher who collects the data after the block will be blinded to the study group. All study outcomes will be evaluated by a dedicated anesthesiologist who will be blinded to the group allocation.Patients will be randomized into 2 groups.

Group (S) patients who will receive sacral erector spinae plane block. Group (G) patients who will receive pericapsular nerve group block. Anesthesia procedure

• The study protocol, sacral erector plane block, PENG block and the numerical pain rating score (NPRS) will be explained to each patient during the preanesthetic counselling. The (NPRS) is 11-point numeric scale ranges from 0 to 10, (where score 0 =no pain and 10 =worst pain imaginable) .
• . Before the participants will be admitted in this study, the purpose and nature of the study, as well as the risk-benefit assessment will be explained to them. An informed consent will be obtained from participants. Patients will fast for about 6 to 8 hours for solid meals, for 4 hours for non-clear liquids and for 2 hours for clear liquids before surgery .

Anesthetic technique

• Perioperative anesthesia management will be according to our hospital routine protocol.

• An intravenous cannula will be inserted in the hand and standard monitoring (noninvasive blood pressure, electrocardiography, and pulse oximetry) will be applied.

• In all patients, spinal anesthesia will be performed in the sitting position. The midline at level of the L3-4 and L4-5 intervertebral spaces will be identified, and spinal anesthesia will be administered using 25-gauge Quincke needle.

• Patients will be immediately placed in the supine position. Spinal anesthesia will be considered successful when a bilateral block to T12, as assessed by loss of cold (cold ice) and pain (a 23-gauge needle) sensations, will be established 10 minutes after the intrathecal injection, the surgery will be done using a lateral approach and a lateral decubitus position. Local Anesthetic Dose, Safety, and Emergency Preparedness

  1. Sacral ESPB: 30 mL of 0.25% bupivacaine HCl (plain), equivalent to 75 mg. PENG block: 20 mL of 0.25% bupivacaine HCl (plain), equivalent to 50 mg . Both doses fall well within the recommended maximum safe dose for elderly patients and selected per anatomical requirements and RCT evidence. The maximum safe dose of plain bupivacaine will be strictly adhered to, defined as 2 mg/kg, not exceeding an absolute maximum of 150 mg.

  2. Slow Incremental Injection: The standard practice is to inject the local anesthetic under ultrasound guidance in small boluses, commonly 5-10 mL at a time, followed by aspiration to rule out intravascular placement and systemic toxicity.

  3. Emergency preparedness measures included:

     (i) Lipid rescue protocol availability: 20% Intralipid solution will be readily available for immediate intravenous administration in the event of local anesthetic systemic toxicity (LAST), according to ASRA guidelines.

     (ii) Monitoring for LAST: Continuous monitoring of neurological status (e.g., dizziness, perioral numbness, seizures) and cardiovascular parameters (ECG, blood pressure, heart rate) will be performed throughout the procedure and during the immediate post-block period.

     (iii) Allergic/anaphylaxis management: Emergency medications (adrenaline, antihistamines, corticosteroids) and resuscitation equipment will be available, with a predefined protocol for prompt management of any hypersensitivity reactions.

     (iv)Emergency airway management equipment will be available at the bed side. (V) Stop rule will be applied if unexpected adverse events (e.g., severe hypotension, arrhythmia, LA toxicity). Postoperative analgesia protocol All patients will receive standardized multimodal analgesia. Paracetamol (1 g every 6 hours) and NSAIDs (unless contraindicated) will be administered as routine analgesics. Opioids will be used as rescue medication according to a unified protocol for both groups. This standardized regimen aims to minimize confounding and ensure that differences in pain scores are attributable to the regional techniques.

Inclusion Criteria:

• Patients with ages from 50 to 90 years of either gender, with diagnosis of intracapsular neck of femur fracture scheduled for elective hip hemiarthroplasty • Patients with an American Society of Anesthesiologists (ASA) physical status I to III.

Exclusion Criteria:

• • Patient refusal.

  • Allergy to local anesthetics and patient with infection at the injection site of block
  • Patient with contraindication to spinal anesthesia.
  • Coagulopathy as INR≥1.5 or platelets ≤80*103 / microliter)
  • Patients with body mass index>35 kg / m2
  • Patients with peripheral neuropathy or diabetic neuropathy
  • Patients receiving opioids for chronic analgesic therapy (cancer, addiction).
  • Cognitive impairment preventing pain scoring.
  • Chronic renal failure requiring dose modification.
  • Bilateral hip fracture or previous ipsilateral hip surgery