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Peter W. Carmel and Fritz J. Cramer

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Early descriptions of the Arnold-Chiari malformation

The contribution of John Cleland

Peter W. Carmel and William R. Markesbery

✓ John Cleland described an unusual congenital anomaly of the brain stem in 1883 in which the medulla was elongated, the fourth ventricle extended into the cervical canal, and the inferior vermis distorted caudally. In 1891 Chiari described two types of brain stem malformation; in one the cerebellar tonsils extended into the cervical canal without medullary deformation, while in the other there was caudal extension of the brain stem and cerebellum and prolongation of the inferior vermis into the cervical canal. The second type was termed the “Arnold-Chiari” malformation by other authors in 1907, and corresponds to the condition described earlier by Cleland. The anatomical features and differences between the types of malformation are tabulated.

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Michael Schulder, Danny Liang and Peter W. Carmel

Object. In this article the authors report on a novel, compact device for magnetic resonance (MR) imaging that has been developed for use in a standard neurosurgical operating room.

Methods. The device includes a permanent magnet with a field strength of 0.12 tesla. The poles of the magnet are vertically aligned, with a gap of 25 cm. When not in use the magnet is stored in a shielded cage in a corner of the operating room; it is easily moved into position and attaches to a regular operating table. The magnet is raised for imaging when needed and may be lowered to allow surgery to proceed unencumbered. Surgical navigation with optical and/or magnetic probes is incorporated into the system.

Twenty-five patients have undergone removal of intracranial lesions with the aid of this device. Operations included craniotomy for tumor or other lesion in 18 patients and transsphenoidal resection of tumor in seven. The number of scans ranged from two to five per surgery (average 3.4); image quality was excellent in 45%, adequate in 43%, and poor in 12%. In four patients MR imaging revealed additional tumor that was then resected; in five others visual examination of the operative field was inconclusive but complete tumor removal was confirmed on MR imaging. In 21 patients early postoperative diagnostic MR studies corroborated the findings on the final intraoperative MR image.

Using a water-covered phantom, the accuracy of the navigational tools was assessed; 120 data points were measured. The accuracy of the magnetic probe averaged 1.3 mm and 2.1 mm in the coronal and axial planes, respectively; the optical probe accuracy was 2.1 mm and 1.8 mm in those planes.

Conclusions. This device provides high-quality intraoperative imaging and accurate surgical navigation with minimal disruption in a standard neurosurgical operating room.

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Peter W. Carmel, J. Lobo Antunes and Michel Ferin

✓ A transorbital, transsphenoidal microsurgical approach to the pituitary stalk and gland was used to collect blood from the hypothalamo-hypophyseal portal system in monkeys. Specimens may be obtained from the entire pituitary stalk, individual long portal veins, or the pituitary sinusoidal bed, with little risk of mortality. Continuous stalk blood sampling was carried out for periods of up to 10 hours. Pituitary sinusoidal-system blood was also collected during transsphenoidal surgery in man. The uses of data concerning hypothalamic-hypophyseal regulation obtained by these methods are illustrated.

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Ryan Holland, David Kopel, Peter W. Carmel and Charles J. Prestigiacomo

Surgery of the mind has a rather checkered past. Though its history begins with the prehistoric trephination of skulls to allow “evil spirits” to escape, the early- to mid-20th century saw a surge in the popularity of psychosurgery. The 2 prevailing operations were topectomy and leukotomy for the treatment of certain mental illnesses. Although they were modified and refined by several of their main practitioners, the effectiveness of and the ethics involved with these operations remained controversial.

In 1947, Dr. J. Lawrence Pool and the Columbia-Greystone Associates sought to rigorously investigate the outcomes of specific psychosurgical procedures. Pool along with R. G. Heath and John Weber believed that nonexcessive bifrontal cortical ablation could successfully treat certain mental illnesses without the undesired consequences of irreversible personality changes. They conducted this investigation at the psychiatric hospital at Greystone Park near Morristown, New Jersey.

Despite several encouraging findings of the Columbia-Greystone project, psychosurgery practices began to decline significantly in the 1950s. The uncertainty of results and ethical debates related to side effects made these procedures unpopular. Further, groups such as the National Association for the Advancement of Colored People and the American Civil Liberties Union condemned the use of psychosurgery, believing it to be an inhumane form of treatment. Today, there are strict guidelines that must be adhered to when evaluating a patient for psychosurgery procedures. It is imperative for the neurosurgery community to remember the history of psychosurgery to provide the best possible current treatment and to search for better future treatments for a particularly vulnerable patient population.

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Peter W. Carmel, Richard A. R. Fraser and Bennett M. Stein

✓ The results of suboccipital craniectomy for varying types of posterior fossa pathology in 50 children are reported. Thirty-five (70%) experienced aseptic meningitis postoperatively, with spiking fever and meningismus; cerebrospinal fluid (CSF) studies revealed pleocytosis, high protein values, and depression of glucose. The absence of bacterial pathogens in serial CSF cultures distinguishes this syndrome from septic meningitis. Aseptic meningitis does not respond to antibiotics, but steroids in suitable doses will modify or suppress the clinical and CSF picture. This syndrome may predispose to postoperative hydrocephalus, but steroid therapy may diminish this risk.

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Martin B. Camins, Frank M. Moore and Peter W. Carmel

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J. Lobo Antunes, Peter W. Carmel, Edgar M. Housepian and Michel Ferin

✓ Luteinizing hormone (LH) and LH-releasing hormone (LHRH) were measured by radioimmunoassay in blood samples collected from the pituitary gland during transsphenoidal surgery in 19 patients. Detectable levels of LHRH were present in 12 patients. Wide fluctuations of LHRH were seen in sequential samples collected at 10-minute intervals, suggesting a pulsatile mode of release. This technique may yield useful data on hypothalamic control of pituitary secretion.

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James K. Liu, Lana D. Christiano, Gaurav Gupta and Peter W. Carmel

Giant craniopharyngiomas in the retrochiasmatic space are challenging tumors, given the location and surrounding vital structures. Surgical removal remains the first line of therapy and offers the best chance of cure. For tumors with extension into the retrochiasmatic space, the authors use the translamina terminalis corridor via the transbasal subfrontal approach. Although the lamina terminalis can be accessed via anterolateral approaches (pterional or orbitozygomatic), the surgical view of the optic chiasm is oblique and prevents adequate visualization of the ipsilateral wall of the third ventricle. The transbasal subfrontal approach, on the other hand, offers the major advantage of direct midline orientation and access to the third ventricle through the lamina terminalis. This provides the significant advantage of visualization of both walls of the third ventricle and hypothalamus as well as inferior midline access to the interpeduncular cistern to permit safe neurovascular dissection and total tumor removal. In this report, the authors describe the transbasal subfrontal translamina terminalis approach, with specific emphasis on technical surgical nuances in removing retrochiasmatic craniopharyngiomas. An illustrative video demonstrating the technique is also presented.