The Double-Deck Cervical Paraspinal Interfascial Block: Combined Cervical Cervicis Plane and Lower Cervical Erector Spinae Plane Blocks for C1–C2 Fusion Under SSEP/MEP Monitoring—A Case Report

Analgesia for craniovertebral junction (CVJ) and high cervical posterior surgery is challenging because surgical exposure disrupts multilevel posterior cervical musculature and irritates the upper cervical dorsal rami, particularly C2–C3. Procedures performed with somatosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring also favor posterior, motor-sparing regional techniques. We describe a “double-deck” strategy combining an upper cervical cervicis plane (CCeP) block with a lower cervical erector spinae plane (ESP) block for posterior C1–C2 fusion performed under multimodal intraoperative neuromonitoring (IONM). A 27-year-old man (95 kg; body mass index 26.31 kg/m ² ) with a displaced type II odontoid fracture and cord edema underwent posterior C1–C2 fusion under propofol-based total intravenous anesthesia and SSEP/MEP monitoring. After induction, prone positioning, and before incision, bilateral ultrasound-guided lower cervical ESP blocks were performed at the C6 transverse process and bilateral upper cervical CCeP blocks were performed at the C3 level, targeting the intersemispinal plane between the obliquus capitis inferior and semispinalis capitis muscles. Each injection used 10.5 mL of 0.2% ropivacaine with 2 mg dexamethasone, for a total injectate volume of 42 mL, total ropivacaine dose of 80 mg, and total perineural dexamethasone dose of 8 mg. Intraoperative fentanyl requirement was 300 μg over approximately 6 hours. SSEP/MEP signals remained stable without reported qualitative deterioration. Pain scores remained low during the first 24 hours on scheduled intravenous paracetamol, and no rescue analgesic was required. This case suggests that combining a C3-level CCeP block with a C6-level cervical ESP block is feasible as part of multimodal analgesia for posterior CVJ surgery performed with IONM. Because the evidence consists of a single case and descriptive physiological data, these findings should be interpreted cautiously and viewed as hypothesis-generating rather than confirmatory.