What is Gamma knife surgery?
Technological advancements in functional radiosurgery during the past half century have led to the development of gamma knife technique for the treatment of intractable cancer pain.Contrary to its name it does not engage a knife but a digitalized radiotherapy unit for meticulous management of tumors. It is a minimally invasive technique that aids in localization of a deep seated space occupying lesion which cannot be accessed via an open surgery. A stereotactic frame is placed on the patients’ head and three dimensional digital imaging is employed to accurately locate the lesion. Subsequently using focused radiation the tumor is precisely targeted selectively sparing the adjacent vital tissues.The prevalence of peripheral Gamma Knife surgery has increased over the years since metastases have been on the rise.
Types of disease managed by gamma knife surgery
- Trigeminal Neuralgia: Using focused radiation beams to severe the trigeminal root in the posterior fossa has resulted in pain free symptoms without additional medications.
- Arteriovenous malformations: Gamma knife is used to rupture the abnormally proliferative endothelial cells within the AV nidus which gradually develops a concentric narrowing and hyalinization of the lumina leading to vessel occlusion.
- Acoustic neuromas:Owing to its long-term safety and efficacy, most the patients with acoustic neuroma preferably those with an average extracanalicular tumor diameters of 35 mm; opt for stereotactic radiosurgery over microsurgical alternatives.
- Meningiomas:In meningioma patients particularly those who have the lesion around the skull base or sagittal sinus; there are chances of undesirable development of new neurological deficits when a complete surgical resection is performed. Hence, Gamma knife radiosurgery represents an important therapeutic option.
- Pituitary tumors: Fractionated radiation therapy has been the mainstay of treatment for unresectable pituitary adenomas due to its ability to effectively control the rate of tumor growth and also reducing the hypersecretion of hormones by the tumor.
- Other skull based lesions: Skull based tumors such as Jugular Foramen Schwannomas and Trigeminal Schwannomas, which are asubstantial challenge to gain surgical access; are preferred for gamma knife radiosurgery.
- Brain metastases:It is estimated that brain metastases develop in 10–30% of patients with cancer.As most of the chemotherapy or immunotherapy drugs have difficulty penetrating the blood-brain barrier hence gamma knife therapy is an acceptable treatment options in these cases.
- Glial neoplasms and Pineal region tumors: The malignant cases are better managed via stereotactic radiotherapy.
- Movement disorders:The original purpose of the Gamma knife during its induction was to be able to treat functional disorders through a small, ell-circumscribed lesion within the brain without opening the skull or without the need for heat or mechanical destructive forces.
Treatment Procedure of Gamma knife surgery
- Preoperative preparations: Basic clinical examinations such as blood tests are carried out and the expected results are discussed. The treatment team comprises of a radiation oncologist, a medical physicist and a neurosurgeon who work together to impart suitable treatment. The medical physicist bears the responsibility to impose proper safety measures leading to unhindered functioning of the gamma apparatus and to assure that contemporary computers and latest software isemployed in the procedure. It is customary to explain that most of the treatment is painless. Nevertheless, when the stereotactic frame is fitted on the patient’s head it is normal to feel uncomfortableor experience slight painin the region of pin fixation or in the external auditory meatus lasting for a few minutes.
- Intraoperative day: It is usual for the patient to receive premedication, nevertheless it is not obligatory and depends on the surgeon’s judgment. Diazepam is the commonly usedsedative dexamethasone is the preferred drug to relieve radiation-induced nausea and vomiting. It is to be given half an hour prior to applying the frame. In subjects with large tumors which are present in criticalregions, it may be desirable to extend the dosage of dexamethasone for a couple of days postoperative followed by gradual withdrawal over a week or more. Itis done to reduce the risk of complications such as acute swelling following Gamma Knife radiosurgery.
- Prior to the surgery: Patient’s hair is washed in an alcohol based disinfectant solution. Unlike open surgical interventions, no shaving of hair is required. The patient would be asked to remove any piece of jewelry or metallic objects on the body.
- Treatment procedure: The patient is placed in a supine position or sitting in a chair and the frame is applied. After the aluminum head frame is applied therest of the day is essentially tedious. In case of an arteriovenous malformation, an angiogram would be advised. The patient might experience slight discomfort during this procedure. With the advent of modern contrast media, angiogram has become quite tolerable in recent years. In other cases a CT or MRI examination can be performed. Subsequent to the diagnostic examinations, the patient is returned to the ward. This period is utilized by the operative team to evaluate to radiographic reports and devise the correct dosage pattern for the patient.This might take approximately 30-60 minutes. After that the patient is brought back to the Gamma Knife suite and prepped for the radiotherapy session. The patient needs to be placed in and out of the machine several times during the Gamma knife surgery. The procedure involves focusing gamma rays precisely on the lesion throughapproximately 200 openings in the head frame. These individual gamma rays have less radiation strength but when they converge at a focused area, their strength gets added up and become strong enough to destroy the pathologic tissues yet preserve the normal tissues in the vicinity. Though the entire process is tedious yet it’s entirely painless.
- Following the procedure: The head frame is removed and a bandage is applied over the operative site. Patients treated for arteriovenous malformations are immobilized depending on the angiographic procedure while othersare mobilized at their convenience. The pins used to secure the head frame can leave pressure points that can cause acute pain for a short time in some patients. This is managed byreapplication of the head bandage with less compression and if the need be, an intramuscular injection of an opiate analgesic can also be given. Most of the cases resolve with this.
- Postoperative day: This is the most suitable time to educate and counsel the patient. He/she is provided detailed information on the further outlook and follow-up instructions, which is long term in most of the cases. The patient is guided through the unwelcome restrictions in activity which is to be strictly followed. Patients are in and out of the hospital within a day and can resume their normal routines soon after treatment.
Complications/Risk factors associated with Gamma knife surgery
- Headache: The patient might experience minor headache due to the pressure exerted by the pins of the head frame, but it will gradually subside. Medications can be given to relieve the pain.
- Nausea and vomiting: Premedications would be given to prevent its occurrence.
- Dizziness and loss of balance: Some patients might feel claustrophobic while undergoing the procedure.
Am I a Good Candidate for Gamma knife surgery?
Patients with arteriovenous malformations and brain and spinal lesions in inaccessible areas are best suited for gamma knife surgery. Patients who cannot undergo an open surgery due to age or other health conditions can opt for this procedure. It is equally beneficial for pediatric patients as it minimizes the risk of radiation after effects, as children as more predisposed to develop late effects from undue radiation.
Recovery time and Aftercare
Gamma knife surgery is performed as a day procedure and the patient would be in and out of the hospital the same day. The patient might experience minor headache due to the pressure exerted by the pins of the head frame, but it will gradually subside. Medications can be given to relieve the pain. It is advisable to have a family member next to you during the first postoperative day. You can gradually resume your daily activities within a day nevertheless strenuous work is to be restricted till complete resolution of the lesion. The patient needs to sleep with head elevated on a pillow for a couple of weeks. This helps reduce pain and swelling. The head bandages need to replaced with a fresh one for the first 2-3 days after the surgery. The site can be cleaned with soap and an antibiotic solution can be applied to hasten the healing process. Washing hair is advisable at least two days after the surgery so that the inflammation sites corresponding to pin placement would have been reduced by then and also cleaning the region helps prevent infection.
Success Rate of Gamma knife surgery
Gamma knife radiosurgery represents between 14 and 17% of the neurosurgical procedures performed worldwide.By one years time, 75% to 90% of patients will have obtained pain relief.
Benefits of Gamma knife surgery
- It is completely painless and you won’t feel a thing. You can easily take a nap or little to something soothing during the procedure.
- It is relatively safe and effective treatment option with sustainable results.
- It is great alternative for lesions in inaccessible regions or within clear proximity of vita structures that could be easily harmed during an open approach.
- The anatomical structures are not directly manipulated that prevents direct trauma.
- There are minimal complications as compared to an open surgery.
- In case of a lesion located in close proximity of vital anatomical structures, Gamma knife can precisely focus the beam on the pathological tissues sparing the normal anatomical tissues. This is turn also reduces unnecessary radiation exposure.
- It has minimal probability of fatal presentation.
- It is performed as a day care procedure so the patient can go home the same day.
- If the patient’s symptoms are tolerable, other adjuvant treatment modalities could be opted for later.
The cost of the Gamma knife surgery depends on the complexity of patient’s condition, number of therapy sessions, experience of the surgeon and type of hospital. As the procedure requires an advanced setup the prices are comparatively higher than other surgical interventions. Most the European countries have higher charges which is comparatively lower in the Asian countries. This can be attributable to the lifestyle charges which are less in these countries though the surgeons’ expertise remains superior. Especially in India the surgeons are highly skilled and proficient which makes India the best option for availing medical facilities.
Why Choose MedcureIndia?
MedcureIndia prides itself in providing quality care to its patients. We take care of you right from your first visit to the doctor till your complete recovery. We provide you step by step guidance through the entire diagnostic and treatment procedures. You are factually educated regarding your condition and the best suited treatment modality. We are regularly updated regarding the technological advancements in the medical and allied fields thus helping you avail maximum benefits from the treatment. Even procedures such as Gamma knife radiotherapy which is quite expensive in European countries, have been successfully and repeatedly performed by our surgeons with consistent success, which we provide you at affordable prices.
• How much time will it take for me recover from the tumor?
Complete recovery varies from patient to patient and might range from weeks to years. You might experience relief from pain within a day or two after the procedure. In most of the patients the symptoms start subsiding within a month or more. The tumor might take few weeks to months to regress.
• Do I have to lose my hair for the procedure?
No you do not have to shave your head or lose your hair for the Gamma knife surgery. Youjust need to wash your hair with an alcohol based disinfectant solution prior to the surgery. Washing hair is advisable at least two days after the surgery so that the inflammation sites corresponding to pin placement would have been reduced by then and also cleaning the region helps prevent infection.
• Is the procedure painful?
No the Gamma knife procedure is entirely painless. An aluminum head frame is fixed on the patients’ head which can lead to some pressure points. Other than that there is no pain or discomfort.