Definition

Schwannomas are benign nerve sheath tumors. They arise from the supportive tissue within the nerve itself. As these tumors grow, they displaced and compress important nerve fascicles within the nerve. This causes pain, weakness, and numbness. Schwannomas usually are solitary and occur at random; however, in a some patients they can be related to a hereditary disorder.

Diagnosis

Because these tumors can occur in any nerve in the body, symptoms are variable. In general, schwannomas can be asymptomatic, cause progressive pain, weakness, tingling, and numbness, or present as a mass in the neck or extremities. Tapping on the mass often causes electrical pain to shoot down the extremity. Although your physician can suspect the diagnosis of a schwannoma on history and examination, it is confirmed with MRI, with and without contrast. It is usually not possible to differentiate a schwannoma from a solitary neurofibroma using MRI preoperatively. Definitive diagnosis is obtained after these tumors are removed. In general, needle biopsy is not recommended.

MRI examples of schwannomas

Treatment Options

Small, asymptomatic schwannomas, especially in older patients, may be observed with serial MRIs. If weakness, numbness, or pain is present, then microsurgery to remove these lesions is recommended. Although radiosurgery may be an option for schwannomas in the head or spine, for the extremities this is not an option.

Surgery

This is the mainstay of schwannoma treatment. The nerve is exposed under general anesthesia. Using a microscope and intraoperative electrophysiological monitoring, the nerve is opened and tumor is carefully removed from the nearby functional nerve fascicles. The tumor usually arises from one small nerve fascicle that has been made non-functional by the tumor-this fascicle is removed with the tumor. The remaining nerve fascicles are preserved, thereby maintaining the nerve's function. Surgery is efficacious in resolving pain, weakness, and numbness in the majority (80-90%) of patients.

Complications

Besides the normal risks of surgery, including reactions to anesthesia and infection, patients who undergo schwannoma removal are at risk for paralysis, numbness, and worsened pain. Although these complications rarely occur, they are possible. The exact risks will be discussed with you prior to surgery and depend on multiple factors, including size and location of the tumor, as well as preoperative clinical status of the patient.

Intraoperative examples of schwannomas

Day of Surgery

Depending on tumor location, surgery is performed either in day surgery or the main operating room. Do not eat or drink after midnight the day before surgery. You may take your usual medications with a sip of water the morning before surgery. You will wake up in the operating room and then be transferred to the recovery room where you can visit with your family. About one or two hours later, you are either discharged home with family or friends, or transferred to the neurosurgery ward. In general, this procedure is not painful for the patient.

Recovery

The operated limb or region may be used for light activity during the first two weeks after surgery. Gentle range-of-motion exercises are encouraged. An occlusive dressing allows you to shower immediately after surgery. After three days this dressing is removed. Underneath are small sterile stickers on the wound that are left in place until you see your surgeon about one week after surgery. You may shower with these stickers. Pathology results are usually ready three to five working days after the surgery. You may return to light work within the first week or two, depending on your specific condition and job description. Resolution of preoperative weakness and numbness may take weeks to months to occur, depending on how long you had it before surgery. Starting two weeks after surgery, physical therapy is prescribed as needed.