Tumor Regrowth
Tumor regrowth is possible after treatment by either microsurgery, radiosurgery or radiotherapy. For microsurgery, advanced techniques by experienced medical teams now make the possibility very slight, but it does exist, and therefore post-treatment checkups by MRI are recommended. Regrowth is much more likely and appears to occur sooner in cases of partial removal. Regrowth following a total surgical removal is not very likely after five years have passed. In general, the recurrence rate following microsurgery is probably less than one in one thousand (0.1%). For radiosurgery (Gamma Knife), a 1998 study of long-term outcomes showed tumor regrowth in 4 patients out of 162 (2.5%) three years after treatment. These patients underwent resection, which was described by the operating surgeons as no different from that of a non-irradiated tumor in three cases and more difficult in one. Long-term data has yet to be reported for tumor regrowth following radiotherapy.

Preservation of Hearing
Except for the smallest tumors, hearing preservation in the affected ear seems an elusive goal when treating acoustic neuroma. In general, for microsurgery, preservation of useful hearing is not likely in removals of tumors exceeding 2.0 cm in diameter. One 1997 study of 60 patients who were candidates for “hearing preservation surgery,” showed 50% success for tumors <1.5 cm and 16% success for tumors that were larger. Another 1997 study of 179 patients showed 48% success for tumors less than 2.0 cm, 25% success for medium tumors 2.0 to 3.9 cm, and 0% for large tumors 4.0 cm or greater. A 1997 House Ear Institute study reported 68% success using the middle fossa approach in 151 cases of tumors 0.5 to 2.5 cm (mean 1.2 cm). For Gamma Knife radiosurgery, a University of Virginia report in 2000 showed that 58% of 36 patients with useful hearing still retained their hearing four years after treatment. Hearing preservation was best with doses to the margin of not more than 13 Gy for tumors less than 1.0 cm. All patients with tumors 3.0 cm and above lost hearing in the affected ear. In 2004, the Gamma Knife Center at the University of Pittsburgh reported a 70-73% rate for preservation of hearing for 313 patients treated at 12-13Gy. The International RadioSurgery Association’s Braintalk (vol.9, 2004) compares reported hearing preservation outcomes: Gamma Knife and Linac radiosurgery, 70-71%; Linac fractionated radiotherapy, 47-61%; Proton beam radiosuregry, 33%; fractionated Proton beam, 31%.

Headache
Headaches as a symptom of acoustic neuroma are uncommon, but may occur with medium or large acoustic neuromas. Headaches after microsurgical removal of an acoustic neuroma are unfortunately quite common and can be severe, persistent, difficult to treat and sometimes debilitating. The 1998 ANA Survey showed that 78 % of 692 patients who reported having headaches after surgery experienced them in a very severe form, and for 64% the headaches persisted for more than three years. More retrosigmoid patients experienced severe headaches than those having had the translabyrinthine or middle fossa approach. For radiosurgery and radiotherapy, the incidence of post-treatment headaches has been very low and the severe, persistent variety has not been reported. One 1995 study of outcomes for radiosurgery reported new onset of headache at 5%. A March 2001 article in ANA NOTES argues convincingly that the unique factor behind the severe headaches related to microsurgery is bone dust residue resulting from the drilling needed to expose the tumor in the internal auditory canal. Careful bone dust removal, and other preventive measures to minimize muscle incisions and replace skull bones (cranioplasty), were recommended to reduce the incidence and severity of headaches after acoustic neuroma surgery.

Balance
In the 1998 ANA Survey, 791 out of 1,469 patients (53%) reported worsened balance after microsurgery, and depending on size of the tumor, 69-74% said they had permanent difficulty. Only a small number of patients (55) had been treated by radiosurgery; 12 (22%) reported permanent difficulty. What the difficulties were in all cases was not described. As stated in a 1999 article in ANA NOTES, “Essentially everyone who has been treated for an acoustic neuroma experiences difficulty with balance to some degree. . . When a tumor is surgically removed, the change in balance function occurs quickly with no further change over time. With radiation, change occurs more slowly, often with some persistence of balance function on the treated side.”

Facial Weakness
Over the last ten to twelve years, improvements in microsurgical techniques and refinements in radiation instrumentation and procedures have greatly reduced the risk of facial weakness following treatment for acoustic neuroma. For microsurgery, facial nerve function is now being preserved in a very high percentage of patients. Tumor size continues to be an important factor influencing success. For radiosurgery, since the introduction in 1991-92 of lower dosages to the tumor margin, the risk of temporary facial weakness has been cut from 17-33% to 1-2%, and the risk of permanent facial weakness is now at 0%. In 2005, the University of Pittsburgh Gamma Knife Center reported 100% facial nerve preservation for patients treated with 12-13Gy. Complete loss of facial sensation as a consequence of Gamma Knife treatment has never been reported. The International RadioSurgery Association’s Braintalk (vol 9, 2004.) compares reported rates of permanent facial weakness for the various radiation technologies: Gamma Knife radiosurgery, 1-4%; Linac radiosurgery, 8-12%; Proton beam radiosurgery, 9%; fractionated Proton beam, 0%; Linac fractionated radiotherapy, 2-12%.

Depression & Memory
The 1998 ANA Survey of acoustic neuroma patients showed that 35% experienced depression after surgery, and 10% reported this as a permanent difficulty. A 1993 article in ANA NOTES reported rates of 50 to 60% and made the interesting observation that the post-surgical depression rate appears to be higher for acoustic neuroma patients than for other surgeries. Regarding this complication, AN patients have said they would have liked more information about what to expect post-surgically. Memory deficits after treatment for acoustic neuroma is a related complication. The 1998 ANA Survey showed 25% of microsurgery patients (372 out of 1,469) reported memory difficulties. For radiosurgery, 5 patients out of 55 (9%) reported the problem. Memory difficulties have been shown to be a symptom of depression, for one thing. They may also result when attention mechanisms are interfered with by hearing loss, imbalance, fatigue and/or pain. Then too, it has been theorized that an area of the brainstem (the locus ceruleus) that is important for attention, learning and memory may be disturbed by the size and/or treatment of an acoustic neuroma.

Tinnitus
Tinnitus is a common symptom of the hearing disorder associated with acoustic neuroma. A 1996 poll of 500 ANA members showed that 372 (75%) experienced tinnitus before surgery. In 43 of these cases, the tinnitus went away after surgery, while 76 of the 500 patients developed tinnitus after surgery. A 1998 House Ear Clinic survey of 500 patients showed that about 40% reported the tinnitus was better after surgery, 50% said it was the same, and 10% felt it was worse. The Gamma Knife Center at the University of Virginia reported that 26 of 153 radiosurgery patients (1989-99) had tinnitus at treatment; in 3 cases the tinnitus improved while in the rest it was unchanged. One new case of tinnitus appeared on follow-up. There is as yet no definitive treatment for tinnitus, but various methods exist for coping with the discomfort. The American Tinnitus Association is a valuable source of information about existing treatments and new research.

Eye Problems
Eye problems after surgery due to facial nerve weakness are a major problem for many AN patients. Complications such as failure in tear production, lid closure, or blink reflex may affect 50% or more of acoustic neuroma patients with medium or large tumors. The 1998 ANA Survey placed eye problems second after hearing loss in its list of fifteen most reported long-term problems after surgery. Eye problems have not been reported as much for radiation treatments. A 1998 report on complications after radiosurgery for 115 patients showed one case of dry eyes and one of watery eyes.

Cerebrospinal Fluid (CSF) Leakage
CSF leakage from the nose (CSF rhinorrhea) has occurred in as many as one in eight surgeries for acoustic neuroma removal. The 1996 ANA Registry reported CSF leakage in 11% of 3,068 cases. The majority of cases occur in the first few days after surgery and usually resolve in a few days. In some cases, spinal drainage or further corrective surgery is performed. The main risk is meningitus. Radiosurgery and radiotherapy treatment centers have reported some cases of CSF leakage requiring shunts.

Fatigue
See informative article on fatigue related to brain tumors What are some possible effects of brain tumor related fatigue?

In the 1998 ANA Survey, fatigue ranked sixth in the main listing of fifteen basic “long-term problems”, coming only after hearing loss, eye problems, balance disturbance, tinnitus and facial weakness, in that order (Table 4). For microsurgery, 30% of patients (447 out of 1,469) reported fatigue as a long-term problem following treatment. For the small number of radiosurgery patients reporting, 13% (7 of 55) cited fatigue as a problem. The Survey was unable to determine exactly how long fatigue lasted, but it was reported to be a “permanent difficulty” by 30% of the total number of responders (Table 6). A lower incidence of fatigue was reported by patients over 60, and fewer men than women cited it as a post-treatment problem. In the 1998 University of Pittsburgh report on long-term out-comes after Gamma Knife radiosurgery for acoustic neuroma, Table 3 listed complications described by 36 of 115 patients. Balance problems headed the list (7 patients, 6%). No patient described fatigue as a problem. A recent (2003) survey from Denmark has looked at the long-term impact of surgery for 716 acoustic neuroma patients for the period 1976-2000. Forty-nine per cent of patients reported increased fatigue. Interestingly, 37% of 216 “wait-and-watch” patients compared in the survey also reported increased fatigue.

Fatigue is a persistent feeling of listlessness and lack of energy. It’s a tiredness not related to physical activity; in fact, one of its main characteristics is reduced motivation and capacity for physical and/or mental activity. Fatigue of this type is a common experience of brain tumor patients. As a general rule, radiosurgery/radiotherapy patients do not describe this type of fatigue as a post-treatment problem. And fortunately, too, probably the majority of AN patients who undergo microsurgery will experience such fatigue for only a relatively brief period following treatment. That is, for a time there is a dramatic decrease in energy because of the emotional impact of the diagnosis and the trauma of anesthesia and a long surgery, but usually within 3-4 months the patient “bounces back” and resumes normal activity. Some surgery patients, however, may continue to feel a profound tiredness lasting for 1 to 5 years or longer. Such prolonged fatigue can seriously affect emotional well-being, social ability, concentration and quality of life in general. Acoustic neuroma patients need to keep in mind that, as life experiences accumulate, fatigue-causing conditions not related to AN may occur to complicate and confuse perceptions. Fatigue can also be caused by diabetes, hypothyroidism, fibromyalgia, shortness of breath, sleep apnea, stress, depression, prescription drugs, iron deficiency anemia, or even a special condition being defined as chronic fatigue syndrome (CFS).