Bell´s Palsy, a lower motor neuron injury that causes facial asymmetry due to facial weakness ranging from mild to total paralysis. Most of cases without determining a definitive established cause. The only authenticated findings are inflammation and edema of the facial nerve. In Mexico, it is among the first causes of medical attention. In the Mexican Clinical Practice Guide for Bells Palsy, thermotherapy, massage, and active exercises are recommended for its management. Perineural dextrose injection therapy (PIT) is a new treatment for peripheral neuropathy, which consists of injecting 5% buffered dextrose close to nerve pathways to restore nerve function and movement. Objective: Determine the effectiveness of perineural injection with dextrose versus conventional physical therapy for the treatment of patients with Bell´s palsy. Material and methods: Clinical trial, experimental, prolective, longitudinal, comparative and heterodemic. Resources and infrastructure: It will be carried out within the facilities of the Unidad de Medicina Física y Rehabilitación región centro. In human resources, doctors both specialists and residents in Rehabilitation Medicine and physical therapists. In material resources, stationery, for electroneuromyography study, perineural injection therapy, hand hygiene and disinfection, and for conventional rehabilitation therapy.

This study aims to evaluate the efficacy of dextrose perineural injection therapy while motivating and serving as a foundation for future studies to compare or create alternatives and therapeutic methods tailored to the needs patients, with the goal of improving functionality and aesthetics.

• Inclusion Criteria: Patients with Bell's Palsy who:

  • Age 18 years and older.
  • Both male and female.
  • Duration of symptoms longer than 6 days.
  • Apparently healthy, without any associated comorbidities such as diabetes mellitus, obesity, hypothyroidism, hyperthyroidism, metabolic syndrome, or any neurological disorder.
  • Grade III (moderate dysfunction), IV (moderate to severe dysfunction), V (severe dysfunction), or VI (total paralysis) according to the House-Brackmann Classification.
  • Exclusive attention from UMF 2, 3, 4, 6, 11, 16, 29, 34, 35, 42, 94, 120 and the Physical Medicine and Rehabilitation Unit in the central region (employers and beneficiaries).
  • Exclusive attention from the UMF belonging to Mexico City (beneficiaries only).
  • Patients willing to participate in the study confirmed with signed informed consent.

• Exclusion Criteria:

  • Active smokers.
  • Patients with central facial paralysis.
  • Patients with peripheral facial paralysis secondary to tumors or surgical treatment.
  • Patients experiencing more than second episode of Peripheral Facial Paralysis.
  • Patients with cognitive and/or mental impairments.
  • Patients undergoing additional private therapy.
  • Patients with bilateral facial paralysis.
  • Pregnant patients.
  • Patients unwilling to participate in the study.
  • Patients who have received prior rehabilitation, laser, electrotherapy, or acupuncture.

• Elimination Criteria:

  • Patients who do not attend rehabilitation sessions.
  • Patients diagnosed with Sars-cov2 infection during the study.
  • Patients who discontinue treatment.
  • Patients developing other pathologies requiring special treatment.
  • Patients wishing to withdraw from the study.

• Baseline: Adequate assembly with balanced groups through randomization and clinical stratification.
• Execution: Proper application of the experimental maneuver with established doses at each injection point.
• Outcome: Same number of evaluations in both groups and a 20% increase in sample size in case of losses.
• Masking: Triple-blind study.