Within six months of treatment, 60% of patients are free of facial pain and are able to discontinue all medications. Another 30% are pain free using a small does of medication, which does not produce side effects. Thus 90% of patients are successfully treated with Gamma Knife. With long-term follow-up the overall success rate drops to about 75%, which is similar to the long-term success rate of microvascular decompression and better than that of radiofrequency, glycerol, or balloon treatment. A second treatment may be performed if the first treatment was unsuccessful or if the pain recurs after an initial successful treatment. About 80% of patients treated a second time obtain either complete or near complete relief of trigeminal neuralgia pain. About 15% of treated patients will develop temporary facial numbness usually 6-9 months after the procedures and about 5% will develop permanent facial numbness. Although particularly bothersome at first, most patients with facial numbness rapidly get used to it and most are delighted to exchange their facial pains for some numbness.

Many patients who suffer from facial pain have symptoms that are not completely typical of trigeminal neuralgia. These atypical features include a constant background aching facial pain, spread of pain beyond the normal area supplied by the trigeminal nerve (such as the head or the neck), and absence of the trigger areas from which typical trigeminal nerve pain can be activated. All forms of medical and surgical treatment including Gamma Knife treatment are not as successful in these atypical forms of facial pain as in typical trigeminal neuralgia. Gamma Knife treatment of patients with atypical symptoms results in complete pain relief only rarely. About 60% of Gamma Knife treated patients will gain at least a 50% reduction in their facial pain. Later recurrence of pain is more common in patients with atypical symptoms than in those with typical trigeminal neuralgia. The risk of facial numbness is no different in patients with atypical symptoms compared to patients with typical trigeminal neuralgia.

Kondziolka D, Lunsford LD, Flickinger JC, Young RF, Vermeulen SS, Duma CM, Jacques DB, Rand RW, Regis J, Peragut JC, Epstein MH, Lindquist C: Stereotactic Radiosurgery for trigeminal neuralgia: A Multi-Institution Study Using the Gamma Unit, J Neurosurg 1996 Jun; 84(6): 940-945

Young RF, Vermeulen SS, Grimm P, Blasko J, Posewitz A: Gamma Knife Radiosurgery for treatment of trigeminal neuraligia: idiopathic and tumor relation. Neurology 1997; 48(3):608-614.

Young RF, Vermeulen SS, Posewitz A.: Gamma Knife radiosurgery for the treatment of trigeminal neuralgia, Stereotact Funct Neurosurg, 1998; 70(Suppl 1): 192-199.

Young RF, Stereotactic radiosurgery of the trigeminal nerve root for treatment of trigeminal neuralgia, in Neurosurgical Operative Atlas Volume 7. S. Rengchary, R.Wilkins, eds., American Association of Neurological Surgeons Publications, 1997; 87-91

Young RF, Radiosurgery versus Microsurgery for trigeminal neuralgia, Current Techniques in Neurosurgery. M Saleman, ed, Current Medicine, Inc., Springer, 1998; 35-43.

Young RF, Treatment of trigeminal neuralgia by radiosurgery with the Gamma Knife. In: Fisher WS, ed. Perspectives in Neurological Surgery, New York: Thieme, 1999; 9(2): 1-16

Gamma Knife thalamotomy has been proven a safe and effective surgical treatment alternative for Essential Tremor. The Gamma Knife Center neurological staff have performed over 300 thalamotomy procedures for ET since 1993. Over 85% of the patients have achieved either total or near total loss of their tremors. While it is particularly applicable to patients who are not ideal candidates for deep brain stimulation, it can be offered to all patients who are considering surgical intervention for ET.

Young RF, Vermeulen SS, Meier R, Li F: Gamma Knife Thalamotomy for Treatment of Essential Tremor: Long-Term Results, J Neurosurg 2009 Nov; 0(0): 1-7.

Young RF, Vermeulen SS, Posewitz A., Grimm P, Blasko J, Jacques DB, Rand RW, Copcutt BC: Functional Neurosurgery with the Leksell Gamma Knife; Radiosurg 1996; 218-228.

Young RF: Functional Neurosurgery with the Leksell Gamma Knife, Stereotact Funct Neurosurg 1996; 66(1-3):19-23.

Young RF: Gamma Knife Radiosurgery as a Lesioning Technique for Movement Disorder Surgery, LD Lunsford, topic ed, JA Jane, ed, Neurosurgical Focus 1997 Mar; 3(3).

Young RF, Shumway-Cook A, Vermeulen SS, Grimm P, Blasko J, Posewitz A, Burkhart WA, Goiney RC: Gamma Knife radiosurgery as a lesioning technique in movement disorder surgery. J Neursurg 1998 Aug; 89(2):183-193.

Young RF, Jacques S, Mark R, Kopyov O, Copcutt B, Posewits A, Li, F: Gamma Knife thalamotomy for treatment of tremor: long-term results, J Neurosurg, (Suppl 3) 2000; 93: 128-135.

Young, RF. Gamma Knife Treatment for Movement Disorders, Seminars in Neurosurgery, 2001, Volume 12: 233-243.

Young RF, Posewitz A., Non-Invasive Lesioning: Functional Radiosurgery. In Alexander EB III and Maciunas RM, eds. Advanced Neurosurgical Navigation. New York: Thieme, 1999; 41:507-517.

Young RF. Clinical applications: Pain, Movement Disorders, and Epilspy. In: German IM, ed. LINAC and Gamma Knife Radiosurgery, Park Ridge, Illinios, American Association of Neurological Surgeons: 2000; 231-252.

Young RF. The Gamma Knife in Movement Disorder Surgery. In Lozano AM, ed Movement Disorder Surgery Progress and Challenges, Basel: Karger, 1999.

Young RF. Gamma Knife Treatment for Movement Disorders. InSeminars in Neurosurgery, ed Advances in Neurosurgical Treatment of Movement Disorders. New York: Thieme, 2001, 12(2): 233-243

On the average, over 90% of acoustic neuromas treated with Gamma Knife show disappearance, shrinkage, or no growth after treatment. Hearing is preserved in more than half of the patients treated with the Gamma Knife and for smaller tumors the rate of hearing preservation may approach 70% or more. Hearing loss, which does occur after Gamma Knife treatment, is usually gradual so patients who may have lost hearing the other ear have a chance to learn other communication skills and adjust to their impending hearing loss. Such a problem arises in patients whose acoustic neuroma is related to Neurofibromatosis because these patients experience acoustic neuromas on both sides.

Permanent facial paralysis after Gamma Knife treatment of acoustic neuromas is now rare, probably occurring in 1-2% of patients. The reduction in the rate of facial paralysis is due to the reduced dosages of radiation now being used to treat acoustic neuromas, compared to the past. Facial numbness, dizziness (vertigo), nausea, and balance problems are also uncommon after Gamma Knife treatment.

In a previous publication, our Gamma Knife team found that tiny acoustic neuromas located within the bony internal auditory canal (intracanilicular tumors) were more prone to side effects of Gamma Knife treatment than were larger tumors. Other published studies showed better outcomes for Gamma Knife treatment in comparison to outcomes after surgery, where complications including spinal fluid leakage, infections, post-operative blood clots, and anesthetic complications were common. It is important to understand that surgery may not be a cure for acoustic neuroma. Patients we have treated with the Gamma Knife have had recurrences of the tumor after previous surgery.

Vermuelen SS, Young RF, Posewitz A, Grimm P, Blasko J, Kohler E: Stereotactic radiosurgery toxicity in the treatment of intracanalicular acoustic neuromas: the Seattle Northwest Gamma Knife experience, Sterotact Funct Neurosurg, 1998; 70 (Suppl 1):80-87.

In the experience of the Northwest Hospital Gamma Knife Center about 30% of treated meningiomas will completely disappear after treatment. Thirty percent will shrink in size but still be seen on follow-up MRI scans. Another 30% will not shrink but will not grow either. About 10% of meningiomas will continue to grow in spite of Gamma Knife treatment. Options available in that case include a second Gamma Knife treatment, surgical removal of the tumor, or in some cases radiation therapy or chemotherapy. Most meningiomas are benign but small percentages are malignant and continue to grow in spite of all forms of treatment.

We have not experienced any deaths attributable to Gamma Knife treatment but some patients have experienced temporary or in rare cases permanent side effects of the treatments. We have found that we have better results and very minimal side effects when we treat meningiomas located at the base of the skull compared to those located near the top of the head. Our experience in comparing the treatment of meningiomas in these two locations has been published. Even large meningiomas or those located close to important structures such as the optic nerves may be treated with Gamma Knife. In such cases we may recommend more than one treatment, perhaps separated by several months.

Vermuelen SS, Young RF, Li, F, Meier R, Raisis J, Klein S., Kohler E: A Comparison of Single Fraciton Radiosurgery Tumor Control and Toxicity in the Treatment of Basal and Nonbasal Meningiomas, Sterotact Funct Neurosurg, 1999; 72 (Suppl 1) 60-65.

In several studies, Gamma Knife radiosurgical treatment has been shown to significantly improve the survival of patients with malignant gliomas when used as a boost treatment following completion of radiation therapy. When Gamma Knife treatment is delayed until the tumor has recurred or progressed, the benefits are less evident. We recommend that all patients with malignant gliomas be evaluated for a Gamma Knife radiosurgical boost treatment immediately following completion of radiation therapy.

Sometimes patients with malignant tumors seek Gamma Knife treatment before surgery or in the hopes of avoiding either surgery or radiation therapy. We do not believe that radiosurgery alone is a sufficient treatment for malignant gliomas because these tumors infiltrate into the brain beyond where they may appear on scanning images. We believe the best treatment for malignant gliomas combines all of the available treatments into a cohesive overall treatment plan. Complications of Gamma Knife treatment in the form of brain swelling are more common than after the treatment of other types of tumors. However, such complications can usually by managed with steroid medications.

Young RF: The Role of the Gamma Knife in the Treatment of Malignant Primary and Metastatic Brain Tumors, CA Cancer J Clin 1998 May-Jun; 48(3):177-188.

Young RF: Radiosurgery for the treatment of brain metastases. Seminars in Surgical Oncology 1998 Jan-Feb; 14(1):70-78

Larson DA, Gutin PH, McDermott M, Lamborn K, Sneed PK, Wara WM, Flickinger JC, Kondziolka D, Lunsford LD, Hudgins WR, Friehs GM, Haselsberger K, Leber K, Pendl G, Chung SS, Coffey RJ, Dinapoli R, Shaw EG, Vermeulen S, Young RF, Hirato M, Inouhe HK, Ohye CC, Shibazaki T: Gamma Knife for glioma: Selection factors and survival. Comment in: Int J Radiat Oncol Biol Phys 1996 Dec 1; 36(5):1279-1280 and Int J Radiat Oncol Biol Phys 1996 Dec 1; 36(5): 1045-1053.

Young RF, Vermeulen SS, Posewitz AE, Jacques DB, Rand RW, Duma CM, Copcutt BC, Henderson J, Bolles GE, Breeze RE, Johnson SD, Pribil SG: Abstract. Gamma Knife Radiosurgery for Treatment of Multiple Brain Metastases, Stereotact Funct Neurosurg 1995; 64:92-93.

Young RF, Jacques DB, Duma CM, Rand RW, Henderson J, Vermeulen SS, Grimm P, Blasko JC, Posewitz A, Copcutt BC, Bolles GE, Breeze RE, Pribil SG, Winston K, Johnson SD: Gamma Knife Radiosurgery for Treatment of Multiple Brain Metastases: A Comparison of Patients with Single versus Multiple Lesions, Radiosurg 1996; 92-101.

Pituitary tumors may cause excess secretion of hormones leading to high levels of prolactin, growth hormone, or the hormone that cause the production of cortisone (ACTH). These conditions may cause infertility, Acromegaly, or Cushing’s Syndrome. Some pituitary tumors do not produce excessive hormones but may grow and cause pressure on the optic nerves leading to loss of vision. In some cases pituitary tumors do not produce excessive hormones but may grow and cause pressure on the optic nerves leading to loss of vision.

In other cases, pituitary tumors destroy the cells that normally produce pituitary hormones leading to a condition called hypopituitarism. In that situation it is necessary for the patient to take hormone replacement medications. The Gamma Knife may be used to treat pituitary adenomas either as primary treatment or to treat tumors which are still present after partial surgical removal or which may recur after what had originally appeared to be a surgical cure. The Northwest Hospital Gamma Knife Center presented results of a study (in combination with a Los Angles Gamma Knife Center) at the 2002 annual meeting of the American Association of Neurological Surgeons held in Chicago. For large pituitary tumors that press on the optic nerves and cause loss of vision, we usually recommend surgical removal first with Gamma Knife treatment of any residual tumor. For smaller tumors the Gamma Knife is an option as well as an initial treatment.

Not all types of pain respond to Gamma Knife treatment and the overall success rate is about 60%. Sometimes combining Gamma Knife treatment and another procedure called bilateral cingulotomy will result in pain relief when either procedure alone is unsuccessful. Our goal is to try to reduce the patient’s pain by at least 50% because total relief of pain is difficult to achieve.

Young RF, Jacques DB, Rand RW, Copcutt BC, Vermeulen SS, Posewitz AE: Gamma Knife Thalamotomy for the Treatment of Persistent Pain, Stereotact Funct Neurosurg 1995; 64 Suppl 1:172-181

Young RF. Ablative Brain Operations for Chronic Pain: Loeser JD, ed. Bonica’s Management of Pain. 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001; 2048-2066.