return to: Otology - Neurotology

Note: last updated before 2017

General Considerations

1. Indications
   1. Primarily for removal of tumors of external ear canal and temporal bone
   2. Extent of spread determines specific degree of temporal bone resection
      1. Lateral temporal bone resection
      2. Subtotal temporal bone resection
      3. Total temporal bone resection
   3. May be sole treatment for tumors with low metastatic potential
   4. May require adjuvant chemo or radiation therapy

Preoperative Preparation

1. Evaluation
   1. Imaging
      1. Non-contrast temporal bone CT
         1. Good initial imaging modality
         2. Evaluation of bone of skull base for tumor extension
      2. MRI with/without gadolinium
         1. Excellent soft tissue discrimination
         2. Less precise bone detail
   2. Carotid Evaluation
      1. Imaging should be used to evaluate for carotid extension
      2. Carotid balloon occlusion can be performed
      3. Cerebral blood flow assessment should be performed if:
         1. Resection of ICA is necessary
         2. Tumor is encasing ICA
         3. Stenosis or abnormality on angiography
      4. These results can help determine treatment strategy
         1. Preservation of ICA
         2. Revascularization
         3. Pre-operative permanent total occlusion
2. Consent
   1. Risks
      1. Death
      2. Stroke
      3. CN Dysfunction
      4. Transfusion 
   2. Benefits
      1. Palliative
      2. Curative 
   3. Alternatives
      1. Doing nothing
      2. Radiation vs chemo 

Operative Procedure

1.  Determination of surgical approach
   1. Location and size of lesion
   2. Malignancy potential
      1. Malignant lesions are best removed en bloc
      2. Benign lesions can be removed piecemeal
   3. Maximize safety, minimize morbidity
      1. Minimize blood loss
         1. Selective vessel ligation
         2. Proximal and distal control of ICA
         3. Selective embolization
      2. Preservation of cranial nerves
         1. EMG monitoring
         2. Preservation of hearing if possible
         3. Preservation of facial nerve function if possible
2. Sleeve Resection
   1. Removes cartilaginous portion of the canal
   2. Not for tumors invading bone 
3. Lateral Temporal Bone Resection
   1. For malignancies of osseous canal
   2. Not for malignancies that go past the medial mesotympanum
   3. Procedure
      1. Post auricular incision, large enough to accommodate all structures to be excised
      2. Complete mastoidectomy 
      3. Epitympanic dissection extending into TMJ
      4. Extended facial recess approach- isolating mastoid segment of facial nerve
      5. Separate incudostapedial joint
      6. Tensor tympani tendon cut
      7. Facial recess approach extended
      8. Separation of specimen en bloc
      9. Other procedures may be needed
         1. Parotidectomy
         2. Partial mandibulectomy
         3. Modified neck dissection 
      10. Closure
          1. If post-op radiation, mastoid cavity must be filled to avoid osteoradionecrosis
          2. Various grafts and flaps have been used to fill defect
             1. Temporalis fascia graft
             2. SCM muscle flap
             3. Radial forearm free flap 
4. Subtotal Temporal Bone Resection
   1. Tumors involving the middle ear
   2. Procedure
      1. Incision- Postauricular, Y-shaped, or preauricular incision
      2. Facial Nerve- transection at stylomastoid foramen or distal branches
      3. Internal Jugular vascular loops
      4. SCM and digastric muscle separated from mastoid tip
      5. Infratemporal Fossa Dissection
         1. Free zygoma from masseter
         2. Mandibular condyle freed
         3. Temporalis reflected inferiorly
      6. Temporal Craniotomy
      7. Dura elevated off petrous bone
      8. Mastoidectomy
      9. Facial nerve management- Sectioning or decompression
      10. Osteotomy- along floor of middle fossa
      11. Delivery of specimen
      12. Reconstruction
          1. Nerve grafts as necessary
          2. Various regional or free flaps used to fill defect
5. Total Temporal Bone Resection
   1. Initial procedure is similar to subtotal resection
   2. Larger temporal craniotomy performed, suboccipital craniotomy
   3. Dura, vessels, CN VII-XI divided
   4. Specimen delivered
   5. Reconstruction

Postoperative Care

1. Monitor for CSF leak
   1. Placement of lumbar drain if necessary
   2. Risk of meningitis increased
2. Monitor for graft function
   1. Pin prick
   2. Doppler
3. CN dysfunction
   1. Dependent on CN involved
   2. Reanastamosis or interposition grafting as appropriate

References

Marsh, Michael; Jenkins, Herman. (2015) Chapter 176. Temporal Bone Neoplasms and Lateral Cranial Base Surgery. In: Cummings Otolaryngology–Head and Neck Surgery, Sixth Edition (2719-2747). Philadelphia, PA: Elsevier Inc.

Jackler RK. (2012) Chapter 66. Neurotologic Skull Base Surgery. In: CURRENT Diagnosis & Treatment in Otolaryngology—Head & Neck Surgery, 3e. New York, NY: McGraw-Hill.