This month Surgical Neurology contains some unique papers, which actually represent the direction of our specialty for the future. There are some well-done clinical studies. Also, there are a number of papers on the molecular events influencing the growth of tumors, the resistance to radiation, and the repair of neuronal injury in peripheral nerve damage. They are understandable so do not worry that you cannot read these studies. The case reports tell stories about interesting observations made by our colleagues that challenge us to think about what nature is telling us. I call these “experiments of Nature” that have clues to the understanding of disease.
The first paper is by Professor Liang-fu Zhou and his colleagues from Shanghai, China. Their work represents one of the best papers on skull base surgery that I have read. They describe their experience with 57 cases of dumbbell-shaped trigeminal neurinomas comparing the standard approaches they used from 1978 to 1984 with the skull-based approaches that they used from 1985 to 2003. Their work shows how their extraduraltransdural trigeminal pore approach enabled them to remove more of the tumors completely with less morbidity and better outcomes than by using the standard techniques. This is the largest series of these tumors in this location in the literature. The paper covers all aspects of the disease from its incidence to the details of the surgical approach to the long-term follow-up. This is a superb piece of work and should be read even if you are not specializing in this area. It is a fine example of how a clinical study should be done. As an aside, I heard Dr Ying Mao, the second author of this paper, present his work on stem cell research in neurosurgery in September 2007. This is one of the best pieces of research in this area I have read and is well thought out. In their department in Shanghai, more than 8000 cases are operated on each year, the largest number of which I am aware in the world. As you can see they do excellent work.
Nakasu et al from Japan studied a DNA repair protein in low-grade diffuse astrocytomas as a marker of tumor progression and malignant change. This marker protein is called MGMA. The authors found that if the DNA repair protein was present, the tumors did not progress to malignant transformation and the patients' survival was longer. But if this MGMA protein was absent, the tumors progressed and the patients' survival times were shortened. Interestingly, if the tumors did not have the MGMA protein, that absence was a marker for sensitivity of the tumor to chemotherapy. This paper is not easy to read for the non–molecular neurosurgeon or neurologist, but it is important. Read the abstract. It is an excellent summary of the paper. The discussion is a very objective analysis of the literature and this work, but may be hard to read. Linda Liau's comments at the end are very helpful in understanding the significance of this paper. What you need to know is that there appears to be a molecular marker that can be stained histologically, even in old specimens that may give a clue to the survival, malignant change, and chemotherapeutic sensitivity of these tumors. Show this paper to your neuropathologists.
Chu Sheng-hua and colleagues from China studied the radiation resistance of tumor cell lines. This is a very interesting subject with again a molecular answer. They found that increasing doses of radiation to various tumor cell lines in culture caused the cells to produce hepatocyte growth factor (HGF) that was related to the radioresistance of the tumors. It appears that HGF can promote tumor cell proliferation and microvascular formation. In the Introduction of their paper, the authors cite another work they have done indicating that, when cells produce HGF, they become resistant to cell death, or apoptosis. If the production of HGF is blocked, agents such as mitomycin C when added to the medium can then be effective in producing cell death. Obviously, the HGF produced by the tumor cell in response to the radiation protected the cell from further injury by radiation or other agents such as mitomycin C. So, radiation to a cell promotes a molecular change, most likely genetic, that is self-protective for the cell. If this genetically induced change to produce molecules like HGF can be stopped, the radiation should have a greater cell-killing effect. This work also explains why cells can survive after radiation. This is a first-rate paper.
Citicoline is a compound containing choline and cytidine, which are substrates in neuronal membrane repair. Özay et al from Turkey used citicoline in an experiment on nerve transection to see whether the compound promoted better nerve repair. It did, in a nicely done randomized study in rats. The authors speculate how this improvement occurs in their discussion. Read the abstract, then the Introduction, and then the Discussion to learn about this new approach. Also, read Ben Rotiberg's comments at the end for a perspective on what this research means. These 3 papers represent progress in the molecular understanding of cell metabolism about which we knew nothing in years before and are a sign of what is coming in understanding disease in the future. This new knowledge will make a quantum leap in disease treatment in the coming years.
Kim et al from Korea report their experience with percutaneous transforaminal endoscopic lumbar discectomy (PTED). This is a well-written report that is objective in its assessment of its subject. It compared microsurgical lumbar discectomy with PTED and found no difference in the patient outcomes with either approach. The PTED procedure is done under local anesthesia with the patient in the knee-chest position. Patients with high pelvis locations prevent the endoscope trajectory from entering into the L5-S1 disc space because of the angle required to reach the space from the top of the hip. Fluoroscopy is required and also an epidurogram and a discogram. The disc fragments are stained with a blue color to make their removal easier under the endoscope. The operating times for microlumbar discectomy and PTED are similar. The comparative costs of each approach are not stated. Percutaneous transforaminal endoscopic lumbar discectomy according to the authors may be as effective as microlumbar discectomy. However, in such choices, the hospital administration will want to know the relative costs of each treatment so that an economic choice can be made. This type of analysis will be required in the future as the costs of healthcare rise. This is a very well done report.
Chibbaro et al from Italy report on their experience in managing patients with acute head injury. They present an algorithm for treatment based on the patient's intracranial pressure (ICP). Decompressive craniectomy was the treatment offered for ICP, which is resistant to treatment along with barbiturate coma. Their logic to reduce ICP is nicely presented. Actually, about half of the patients had a good recovery with aggressive care. Read the discussion. This paper presents a very good summary on how to manage these patients that is easy to read.
Touho from Japan presents a new technique for revascularizing patients with Moyamoya disease.
I asked Ron Pawl of our editorial board to write his impressions of an editorial in the journal Pain on the use of opioids for chronic nonmalignant pain. Ron is a former president of the American Pain Society and a neurosurgeon who has had more than 30 years of interest in this subject.
Beda et al from the USA present the first of a very interesting series of case reports that follow. Beda and colleagues cared for a patient who had a head injury several months before he took an airplane flight. He arrived at their hospital after becoming progressively obtunded by the end of the flight. On computed tomography they found subarachnoid and intraparenchymal pneumocephalus. This case provides an unusual warning to us to be aware of this possibility. In such cases, perhaps taking a computed tomography before the patient flies might be helpful but it is not certain if that will prevent pneumocephalus. Read the report to see what happened and why. What will you do in the future?
Violaris et al from Greece report a fascinating family story in which Von Hippel-Lindau disease was found in successive members and generations of a family. Many of the family members developed cerebellar hemangioblastomas but also had other manifestations of the disease such as renal and pancreatic cysts, retinal hemangioblastomas, epididymic cysts, and a spinal hemangioblastoma. Obviously, this is a genetic story. The discussion provides a nice summary of what is known about Von Hippel-Lindau disease and its genetics and manifestations in multiple organ systems.
Foy et al from the USA present an interesting case of trigeminal neuralgia treated with microvascular decompression, percutaneous retrogassserian glycerol rhizotomy, followed by 2 courses of radiosurgery, and, finally, section of the nerve, all for recurrent pain. The histologic sections showed no damage. Why? Read the authors' discussion and the comments at the end. Kao gives some very good reasons why radiosurgery may fail.
Shigemori et al from Japan present a case of a patient with a jugular bulb thrombosis after trauma, increased intracranial pressure, and negative imaging studies. This is a very rare finding and the case report is instructive.
Yamada et al from Japan describe a case of cervical dystonia that appeared after thalamic tumor removal and radiation to the region. From the progression of the dystonia and the imaging changes, they postulate what the pathophysiologic mechanism is for the dystonia. After treatment with steroids, the edema and radiation necrosis receded and the dystonia improved. Read what they think is the cause.
Pozzati et al from Italy report another “experiment of Nature” in which a fertile woman with a cystic disease of the lungs developed meningiomas after treatment of the lung disease with progesterone, which was the standard treatment for this lung disease. After the progesterone was stopped the meningiomas regressed. The lung disease is sensitive to hormonal treatment. Read the case and the excellent comments at the end by Cone.
Mel Cheatham, who is active in contributing his time to international neurosurgical relief efforts, has written an editorial on why this is an important thing to consider as you plan for the rest of your life. He is directing Surgical Neurology's efforts to help others in need around the world.
Finally, as the year ends, I have written an editorial on our impressions from our trip around the world after seeing and talking with neurosurgeons and people in Asia, Europe, and the USA, “Snapshot of the World—9/2007.” What are others experiencing that is important to all of us as people, physicians, and neurosurgeons?
From all of us at Surgical Neurology to all of our readers, we wish you a Happy, Healthy Holiday and New Year in 2008. Thank you for your interest in Surgical Neurology.
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