Surgery by Dr. Martín-Oviedo and Dr. Souvirón
En SurgSchool, the world's leading app for online surgical training, you can see narrated step-by-step facial reanimation surgeries, including dual reinnervation with hypoglossal and masseteric in facial paralysis of central or peripheral origin. This article summarizes the technique performed by the Dr. Martín-Oviedo and Dr. Souvirón in a patient with Facial paralysis 2–3 months after skull base surgery complicated by brainstem hemorrhage and nuclear lesion of the facial nerve.
Indications and objectives
Dual reinnervation combines:
- End-to-end coaptation of the facial trunk a greater auricular nerve graft.
- End-to-side coaptation of the graft to the hypoglossal nerve (XII) for basal tone and symmetry.
- Direct anastomosis of the masseteric nerve to buccal/zygomatic branch of the facial to activate smile and dynamic mobility.
Objective: restore resting tone y voluntary movement (smile), reducing synkinesis and lingual morbidity.
Preparation and presentation
- Display system: exoscope Vitom-Eagle with high definition 3D, which improves ergonomics and intraoperative teaching.
- Cervico-parotid incision y skin flap by planes up to parotid capsule.
- Careful peeling with selective hemostasis to expose parotid gland y masseter muscle.
Identification of branches of the facial and masseteric muscles
- Anterolateral dissection of the parotid gland to the masseter border; systematic search for buccal and zygomatic branches (guided by accompanying vascular pathway).
- Stimulation y vessel loops to individualize branches; selection of one branch of good caliber and diagonal path towards the cheek/upper lip, ideal for coapting the masseterine.
- Opening of the masseter plane and location of the masseteric nerve to stimulating (clear contraction of the masseter confirms the position). Sufficient release for coaptation without tension.
Graft harvesting and cervical dissection
- Greater auricular nerve: : resection of approximately 6–7 cm, marking the orientation (optional) although evidence suggests revascularization and bidirectional axonal sprouting.
- Cervical dissection along the edge of the neck ECM towards the posterior belly of digastric y submandibular gland until identifying the hypoglossal nerve and descending handle.
Facial trunk and coaptations
- Careful retroparotid dissection to the exit from the trunk of the VII; identification of your fork upper/lower.
- Coaptation 1: Facial trunk ↔ major auricular graft (terminus-terminal), with 2 points fine microsurgical procedures (fewer sutures → less barrier to axonal regeneration).
- Coaptation 2: Graft ↔ hypoglossal (end-to-side on ~⅓ of XII fibers). “End-to-side” technique to provide basal tone and prevent atrophy; clinically negligible lingual morbidity with partial resection of fascicles.
- Coaptation 3: Masseteric ↔ buccal/zygomatic branch (direct terminus-terminal, without graft) for powerful and quick smile.
- Selective sealing with tissue adhesive on anastomoses and sewer system for approximately 48 hours.
Key technical points
- Traction–countertraction constant and meticulous hemostasis in the parotid plane.
- Avoid "wells"in masseter: maintain shallow and clean field so as not to lose the fiber reference.
- Fewer stitches in neurorrhaphy = less interference to axonal growth.
- Congruence of diameters y tension-free coaptation determine the functional prognosis.
- Neurostimulation to confirm motor nerves and maintain oncological/anatomical safety.
Expected results and rehabilitation
- Resting tone early due to the contribution of the XII (symmetry, lip closure).
- Dynamic activation early with the masseteric (“on-command” smile that can be conditioned/trained).
- Rehabilitation speech therapy and early facial mimicry to accelerate cortical relearning and coordination.
- Risks: hematoma, injury to residual branches of the VII, auricular hypoesthesia, synkinesis; clinically low lingual morbidity with partial XII technique.
Conclusion
La dual hypoglossal–masseteric reinnervation offers tone restoration y effective voluntary movement in recent-onset facial paralysis following complex skull base injuries. The combined strategy (TT facial↔graft; TL graft↔XII; TT masseteric↔buccal/zygomatic branch) optimizes functional results with low morbidity when performed with precise microsurgical technique.
