Parotid tumors can recur as single solitary mass or multifocal tumors. Recurrence of the tumor is either due to tumor implantation or inadequate surgical excision during primary surgery. Most tumors of parotid are benign Pleomorphic adenomas and surgery as enucleation or limited local excision can results in a high rate of recurrence.
Even after careful surgical excision the pleomorphic adenoma can still recur, and this is due to either tiny microscopic extensions of the tumor beyond the pseudocapsule of the tumor or rupture of the capsule of the tumor during primary surgical excision. Rupture of the capsule during surgery can also cause spillage of tumor cells in the parotid bed causing recurrence.
Pre op evaluation
Once a parotid tumor does recur, however, its successful surgical excision is facilitated by adequate preoperative clinical, radiographic and cytologic evaluation.
Patients with recurrent parotid tumors need careful preop work up including Ultrasound guided fine needle cytology and MRI imaging. MRI imaging will be very useful to assess the extent of the recurrent tumor and also the amount of parotid tissue left over. The Facial nerve anatomy can be assessed. All these helps in revision surgery.
Surgical treatment in recurrent parotid tumor can be tedious and technically challenging.
An unhurried and meticulous dissection with careful localization and preservation of the facial nerve can be obtained by using an operating microscope and also nerve stimulator.
Facial Nerve status in Redo Surgery
The status of facial nerve function after revision surgery is an important issue. After revision surgery, if superficial lobe is already removed in primary, the chances of damage to facial nerve as neuropraxia or permanent damage can occur. Lot of scarring and fibrous tissue adhesion can make the revision surgery extremely difficult. To avoid careful pre op assesment with MRI imaging and a careful unhurried dissection is required.
Post op Radiation Therapy
Some surgeons advocate post of radiotherapy after second or third revision surgery to prevent further recurrence. If there are malignancy changes in mixed parotid tumors, then radiotherapy must be given.
If there was facial nerve weakness following the initial surgery, revision surgery will be more tedious and have a higher rate of facial nerve neuropraxia or permanent paralysis. Finally it is important to determine if there was a history radiation exposure or the use of therapeutic radiation in the past