Introduction
Hemangioblastomas are tumors of the central nervous system that can occur in individuals suffering from a syndrome affecting multiple organs. Medulla oblongata is the third common location after the cerebellum and spinal cord. Many advancements in the treatment approaches were made, ultimately concluding that surgical management is the primary and ultimate treatment procedure. Although surgical treatment produces better outcomes, it is challenging for the surgeon due to the vast blood supply to the tumor. Complications can also develop due to lesions located especially on the medulla oblongata.
What Are Hemangioblastomas?
Hemangioblastomas are highly vascular tumors occurring in the brain which are benign. They can also occur in the retina and spinal cord. The growth of the tumor compresses the brain and leads to neurological symptoms such as loss of balance, sensation, headaches, and issues with coordination. Few people also develop tumors of hemangioblastomas due to an underlying von Hippel-Lindau syndrome, which is genetic. These individuals develop tumors more than once throughout their lifetime. Based on the relationship of the tumor to the medulla oblongata the position of the tumour can be divided into three types:
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Type 1: Present completely intramedullary.
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Type 2: The presence of larger intramedullary components.
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Type 3: Extramedullary component larger than intramedullary component.
What Are the Symptoms of Hemangioblastoma?
Symptoms of hemangioblastomas can begin at any age. Symptoms can differ from patient to patient. The most common symptoms of hemangioblastomas are listed below.
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Hoarseness
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Dizziness
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Difficulty in walking.
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Neck Pain.
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Vomiting.
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Anorexia (lack of appetite).
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Dyspnea (not able to breathe properly).
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Nystagmus (rapid movements of eyes).
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Bradycardia (slow heart rate).
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Intracranial hypotension.
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Hydrocephalus (fluid buildup in the brain).
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Cranial nerve dysfunction.
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Impaired motor and sensory function.
How Is Hemangioblastoma Diagnosed?
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MRI (Magnetic Resonance Imaging): Location, tumor texture, and its relationship with the surrounding brain tissues. However, it does not delineate the blood supply.
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Computerized Tomographic Angiography: Relationship between tumor and vessels and the skull base. This is a more used technique than digital subtraction imaging.
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Digital Subtraction Angiography: It is done in less time and is easier to perform. It requires lower doses of X-ray along with fewer contrast media, which can even lead to complications.
How Is Surgical Management Done for Hemangioblastoma?
As there is a significant blood supply to the hemangioblastomas, neurosurgeons face challenges in resecting the tumor surgically. Although there are alternative techniques, such as radiosurgery and chemotherapy, for treating these tumors due to the complications and controversies, they are still a second option. Surgical management is the primary treatment option. Better surgical outcomes are obtained by considering the following factors:
Exposure of the Tumor and Surgical Approach:
Obtaining an adequate operative field and exposing the tumor's margins is necessary. A craniotomy can be performed when needed according to the tumor's location. Ultrasonography is used to detect the solid component of the tumor. The position of the insulation is determined based on monitoring neurophysiologically and intraoperative ultrasonography.
Resection of Tumors:
The blood supply should be recognized and divided, followed by the reception of the tumor preserving the main veins. Gel foam and cotton protect the blood from draining from the tumor's supporting veins. Care should be taken not to damage or compress the brain stem tissues while positioning the tumor to preserve the blood vessels. As the tissues involved vascular motor and respiratory areas, damage to the brain stem tissues can result in poor prognosis. Any damage during this phase is temporary and can be recovered quickly. Damage can be permanent if the diameter of the brain stem is less than two millimeters. After all the blood supply is divided and the region is exposed, it can be resected.
Neurophysiological Monitoring:
Temporary damages can be prevented by following neurophysiological monitoring. Electric potentials were monitored for abnormalities as per baseline readings. A lack of indicated changes that sacrifice the blood supply cannot produce any deficits in the brainstem.
Radiation Therapy:
Radiation therapy is an alternative adjunct to surgery that is inoperable and located in sensitive areas. The therapy uses high-energy beams to target and destroy cancer cells. It can be delivered externally (External Beam Radiation Therapy) and internally (Stereotactic Radiosurgery).
What Are the Complications of Managing Hemangioblastomas?
Common complications of surgical management are listed below.
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Gastrointestinal ulceration (injury to the wall or ulceration of the intestine leads to the formation of gastrointestinal ulceration).
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Pneumonia (aspiration can lead to pneumonia).
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Swallowing difficulties.
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Respiratory depression.
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Expectoration difficulties.
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Bleeding.
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Swelling of the tumor.
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Blood vessel occlusion.
Following are the methods to prevent the complications.
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Proton pump inhibitors are used to reduce the occurrence of this complication of gastrointestinal ulceration.
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Interpretation of the patient and tubal feeding until full recovery of respiratory function should be done to prevent pneumonia. Tracheostomy should be performed in cases where examination difficulty has not been resolved.
How About the Recovery Time of Hemangioblastoma?
The recovery time after hemangioblastoma surgery can vary between a few days to months, depending on the size and location of the tumor. In general, the recovery takes several weeks to months. During the initial recovery, the patient may experience some pain, swelling, and discomfort at the surgical site.
After surgery, physical therapy and rehabilitation are recommended to gain strength, mobility, and function. Follow-up appointments with neurologists and oncologists are necessary to monitor the recovery process and progression in health.
What Is the Prognosis After Surgical Management of Hemangioblastomas?
Recurrence of the hemangioblastoma tumors has been noted due to incomplete resection. It was reported that patients who underwent subtotal resection of the tumors showed recurrence. In certain surgeries with severe bleeding, visual access is impaired, and the boundary between the brain stem tissues is impaired. The tumor is clear, making it difficult to remove the entire tumor, which leads to recurrence. It is not only the location, size of the tumor, or the patient's neurological status that predict the outcome, but other factors are also involved.
However, the presence of large tumors and severe neurological system dysfunction before surgery will show a poor prognosis. The time the surgery should be performed also plays an important role in deciding the prognosis. Microsurgery can be performed immediately in symptomatic patients, while in symptomatic patients conforming to tumor growth, the surgery should be performed.
Conclusion
In most patients, effective and safe surgical management of hemangioblastomas of medulla oblongata can be achieved. With the help of various procedures, unwanted surgical errors like mistakenly cutting off the vessels that supply the brain stem can also be avoided. Improvement of proper monitoring during the surgery and microsurgical techniques, along with a good understanding of the blood supply to tumors and removal of the same, can be performed with improved prognosis and improved neurological function.
