Cavernous malformation of the mammillary bodies: neuropsychological implications. Case report

The authors present the first documented case of a cavernous malformation of the mammillary bodies. A 34-year-old woman presented with a 2-month history of headaches and acute memory changes. Magnetic resonance imaging studies demonstrated a retrochiasmatic interpeduncular lesion that was initially thought to be a craniopharyngioma. Operative resection confirmed the diagnosis of a cavernous malformation. This particular case is unique in its destruction of the mammillary bodies and presents further evidence of the relationship of these regions to memory. This report is also the first to document results of pre- and postoperative neuropsychological evaluations that specifically address the memory deficits created by destruction of the mammillary bodies.

Rewarming, ultraprofound hypothermia and cardiopulmonary bypass

Rewarming, a key event in resuscitation from accidental, experimental and clinical hypothermia, is sometimes followed by neurologic, cardiac, and respiratory sequelae and may lead to death. The rate of rewarming has been implicated but not quantified as etiologic in these sequelae. Under anesthesia fifteen dogs were cannulated and connected to an extracorporeal circuit for oxygenation, core cooling and rewarming. They were subjected to ultra-profound hypothermia with a core (esophageal) temperature as low as 1.3 degrees C, cardiac arrest, blood substitution, and continuous low flow perfusion. After 2-3 hours of cardiac arrest, rewarming began. Mechanical activity of the heart was seen between 10 degrees and 28 degrees C and respiration resumed at 29 degrees C. The rewarming rates of the 15 dogs were retrospectively studied. They were placed into three categories (G) based on the outcome. G-I (N=2):no neurological complications, G-II (N=8):transient neurological problems, and G-III (N=5):death, mainly from cardiovascular and respiratory complications confirmed at death by autopsy. Heat gain by each animal was recorded as a function of time for all experiments. The time it took each dog to reach 35 degrees C was determined and a mean was calculated (rewarming rate). Normal body temperature for a dog is 37.8 degrees C. Statistical analysis (ANOVA) was performed ex post facto to determine the relationship between rewarming rate and outcome. Our data contradicts the notion that slow core rewarming from nadir to normal temperature offers better outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracranial cryosurgery in a canine model: a pilot study

Although virtually abandoned decades ago following the introduction of levodopa for the treatment of movement disorders, intracranial cryosurgery potentially offers a simple and accurate means of destroying deep-seated lesions when coupled with computed tomographic-stereotaxic placement techniques. We performed a pilot investigation of the size and histology of brain cryolesions in six dogs, using a 3-mm probe maintained at -160 degrees C for 6 minutes while simiultaneously monitoring the process by real-time ultrasound. Lesion diameter was 1.4 +/- 0.1 cm at less than or equal to 2 days but enlarged to 2.25 +/- 0.21 cm at 1 week, primarily at the expense of white matter. Ultrasound appearance of the lesion was characterized by a hyperechoic ice ball, the size of which consistently underestimated true size (determined by histology). By microscopy, the lesion was a hemorrhagic infarction that incited little surrounding edema and exhibited a sharp transitional zone. These data indicate that the cryosurgical probe can lesion significant volumes of brain in a reproducible and discrete fashion with minimal reaction to the surrounding tissue. Further work is required to clarify the observed "growth" of lesion size between days 2 and 7.