PEDIATRIC BRAIN SURGERY

Often, the treatment of deeply located brain tumors that occur in childhood makes patients smile thanks to the expert surgeons and advanced technology in the field. Early diagnosis of these tumors that require much more experience than those on the surface saves lives.

Our brains regulate our bodies like a conductor of an orchestra. Deeply located tumors among the ones that form in our brains were impossible to operate on in the past. Experienced surgeons equipped with emerging technologies clean the tumors in the majority of the patients and achieve successful outcomes. Professor M. Memet Özek, an expert on Pediatric Neurosurgery at Acıbadem Altunizade Hospital, has described the brain tumors and their treatment.

THREE DEEPLY LOCATED REGIONS: BRAIN STEM, THALAMUS, AND HYPOTHALAMUS

Our brain consists of various regions. The parts that provide some of our functions are located on the cerebrum, while others are located at the cerebellum and the brain stem. The brain stem is regarded as the most important of these. Breathing, ingestion, swallowing, eye movements, all the nuclei of the senses and movements of the muscles are present here. In other words, the main control is on the brain stem. In addition, the brain stem acts like highway where fibers regulating standing and leg-arm movements located on the surface of the brain. The brain stem looks like a cylinder with a 7 cm height and 2.5 cm diameter. Since the middle-lower region is more protected, it is located there.

Thus, if there is a problem in the brain stem it takes a long path to arrive there. As for the path, it is situated among the convolutions of the brain. A separate knowledge, technology, and skill are required to reach that region during an operation.

The second deeply located region is thalamus. This element is located slightly above the brain stem and again in the very middle of the brain. The brain collates and interprets information here. All information received from the cortex are tailored and assessed here and instructions to the target organ are sent.

The last of deeply located regions is hypothalamus. This substructure controls the feelings such as thirst and hunger together with all the hormones present in our bodies. It acts as a laboratory that constantly analyzes the salt and fluid levels in our bodies. There is a certain amount of salt originated ions in each of our cells. These level of these ions must fall in a certain interval. Blood exploits hypothalamus as a laboratory as it circulates the body. Samples of blood are constantly taken and analyzed. If the salt ratio increases, then water is needed to dilute it, and the person feels thirsty.

HOW IS IT TREATED?

Brain tumors are especially manifest themselves during the childhood. 90, 85, and 80 percent of the brain stem, hypothalamus, and thalamus tumors are encountered in this period. Vast majority of thalamus tumors in children are benign, whereas they are malignant in adults. It is important that surgeons have experience in reaching this area. To reach a tumor located on the surface, near to the skull and to operate on that region requires only a short operational duration. However, a deeply located tumor is situated under the brain convolutions and in order to reach there we need to stretch the brain tissue somewhat. And since what we stretch is the brain tissue, we need to treat it in a sensible manner. At this point technology weighs in. Even though the experience and skills of a physician are quite important, we still need certain technological devices. Technologies that are employed are categorized into three groups:The intraoperative monitoring system, which helps to prevent damage to the tissues in the crossing site, is implemented by trained neurophysiologists. There are functions among the veins of the brain located at crossed sites. For instance, there is a center that moves the arm which must not be injured during the operation. Whether any injury occurred or not is again determined by neurophysiologists. These experts attach several electrodes on the scalp and muscles located in the arms and legs of the patient. A signal is sent from above and it is transmission is measured below. Thus, the presence of an excessive strain over that region is immediately detected and it is lowered accordingly. This avoids the risk of apoplexy after the surgery. There is the nucleus of the muscles that move the face in the brain stem. The size of this nucleus is 4×2 mm. Surgeons use a special stimulating probe because of the possibility of damage at any time. The location of this nucleus is detected by touching with this probe. Theoretically we know the location of this nucleus but in the presence of a tumor its position may shift either right or left. Once its location is surely identified, the tumor can be surgically removed. This technique avoids patient to suffer facial paralysis after the operation.

Borders of 70 percent of all deeply located tumors cannot be determined very well. That is, drawing the line between a healthy tissue and tumor is very difficult. Sometimes we encounter cases where surgeons think all of the tumor has been removed where in reality only half was treated. This is usually realized after the operation. Presence of an intraoperative MR creates a big opportunity for these cases. Patients MR image is taken on the operating table through a special device while the skull is open. This provides a visual access to the interior of the brain. Small, unnoticed pieces are spotted this way. This provides an advantage to decide whether any further surgery is necessary while the patient is still on the operating table. Intraoperative MR, that is MR imaging as the patient is on the operating table, opens great venues in the surgery of deeply located tumors. This method which was first implemented in Acıbadem Health Group is now being employed for 8 years. Use of ultrasound techniques during the surgery also contributes to get successful outcomes in operations. Monitoring which tissue is pushed where provides great advantages to the physician.

FINDINGS THAT MUST NOT BE NEGLECTED

• If a child complains of a persistent headache, this should not be neglected… The examiner should look to see if there is any evidence of a pressure increase in the eye ground.
• If the child vomits in a gushing fashion in the morning without eating anything, then this also constitutes a question to explore. Sometimes families misinterpret this symptom as a jealousy of the sibling or not wanting to go to the school. However, if vomiting is experienced every morning, the family must consult an expert at the first occasion.
• If the child is having balance problems while walking, if there is wide based gait as a symptom or if he is clumsy in fine motor skills (hand skills), then these are also considered as important findings. One must consult a specialist on symptoms such as these.

SURGICAL THERPY IS APPLICABLE TO 45 PERCENT OF ALL CASES

Until 1985 a diagnosis of brain stem tumor meant death. Nowhere in the world there was a treatment of brain stem tumors. People also thought all brain stem tumors were of identical type. However, Dr. Fred J. Epstein revealed in 1985 that there were four types of brain stem tumors and they differed significantly among each other. However, only 45 percent of these four types were susceptible to surgical therapy. Professor M. Memet Özek, who took his specialization training under the supervision of Dr. Epstein, deems himself lucky in this regard and says “I was one of the 12 students of Dr. Epstein in 1995. After this training I was interested in all kinds of brain stem tumors. However, there are some special cases for such tumors. For example, 60 percent of patients are not candidates for surgery yet. 55 percent of the cases are those who have no remaining healthy cells on the brain stem. The patient cannot be treated as the tumor has permeated the whole brain stem. In such cases, we need to remove the whole brain stem, but this prevents the patient’s respiratory system to function and heart to beat.”