Intra-parotid Facial Nerve Imaging in Parotidectomy
Condition: Parotid Tumors; Facial Nerve Paresis
MeSH terms: Parotid Neoplasms; Paresis; Facies
Study type: Interventional

Summary: 
      In this study, the investigators will evaluate the clinical usefulness of 3 dimensional
      double echo steady state MRI (3D-DESS MRI) for functional preservation of the facial nerve
      during parotidectomy. Preoperative 3D-DESS MRI imaging can provide information about the
      anatomical relationship between the tumor and the facial nerve in the parotid gland.

      Because the risk of postoperative facial weakness is relatively high in the deep-seated
      parotid tumors, the investigators will exclude the patients with the superficial parotid
      tumors (determined by preoperative CT or US) and only include the patients with deep seated
      parotid tumors in this trial.

      The main outcome of our study is the incidence of immediate postoperative facial weakness,
      and the secondary outcome is the incidence of facial weakness at postoperative 6 months.
    

Detailed description: 
      Surgical removal of tumors arising from the parotid gland (benign or malignant) is treatment
      of choice. However, the most detrimental complication of parotidectomy is facial weakness or
      facial nerve palsy, because the facial nerve crosses in the mid-portion of the parotid gland.

      Numerous studies indicated the incidence of temporary facial weakness as 5-45% and permanent
      facial palsy as 0-15% after parotidectomy. To reduce this complication, the investigators
      will apply the modern technique of MRI imaging to inform the anatomical relationship between
      the tumor and the facial nerve within the parotid gland preoperatively. Three dimensional
      double echo steady state MRI imaging (3D-DESS MRI) has been reported useful for the
      intra-parotid facial nerve imaging.

      Thus, the investigators will evaluate the clinical usefulness of 3D-DESS MRI for functional
      preservation of the facial nerve during parotidectomy. Preoperative 3D-DESS MRI imaging can
      provide information about the anatomical relationship between the tumor and the facial nerve
      in the parotid gland.

      In the retrospective series, the investigators found that there were 25.6% temporary facial
      weakness and 10.3% permanent (> 6 months) facial weakness after parotidectomy for deep-seated
      parotid tumors (plus tumors located in both deep and superficial parotid gland); whereas 6.7%
      and 3.6% facial weakness respectively for superficially located parotid tumors. Because the
      risk of postoperative facial weakness is relatively high in the deep-seated parotid tumors,
      the investigators will exclude the patients with the superficial parotid tumors (determined
      by preoperative CT or US) and only include the patients with deep seated parotid tumors in
      this trial.

      The main outcome of our study is the incidence of immediate postoperative facial weakness,
      and the secondary outcome is the incidence of facial weakness at postoperative 6 months.
    

Intervention name(s): 3D-DESS MRI (3 dimensional double echo steady state MRI)
Intervention type(s): Diagnostic Test
Intervention description(s): 3D-DESS MRI has been reported useful for the intra-parotid facial nerve imaging. It can provide information about the anatomical relationship between the tumor and the facial nerve in the parotid gland.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention