Samuel H. Greenblatt

Anatomy of the human lumbar epidural space: new insights using CT-epidurography

The anatomy of the lumbar epidural space was demonstrated in 40 patients by computed tomography (CT) examinations performed after epidural injection of noninonic radiographic contrast material into the sacral caudal canal via percutaneous catheter. Radiologic evaluation of the epidural space was performed to evaluate possible disc herniation or other pathologic encroachments on the epidural space. In all 40 patients, the examinations showed the posterior epidural space to be divided by the plica mediana dorsalis and an additional transverse connective tissue plane not previously described. The compartmentalized nature of the space may be, at times, responsible for entrapment and coiling of epidural catheters, despite satisfactory technical performance of catheterization for epidural anesthesia. Thirty-one of 40 patients demonstrated a greater amount of fatty tissue within the junctions of the posterior midline epidural connective tissue structures, producing a bulky triangular-shaped structure which might be an impediment to catheterization. The divisions of the anterior and posterior epidural spaces are seen to be more complex than previously described.

Computed Tomography-guided Intracranial Biopsy and Cyst Aspiration

A coordinated series of instruments has been developed for use in computed tomography (CT)-guided brain lesion biopsy and cyst aspiration: a plastic guide needle that is relatively free of CT artifacts, a ball-and-socket holding device for multidirectional sampling, and an aspiration-cutting biopsy needle that reliably produces consistent cores of tissue. Twenty-six biopsy and/or aspiration procedures have been performed on 24 patients with an overall biopsy success rate of 79%. The method is most reliable with highly malignant astrocytomas and least reliable with metastases and unusual primary tumors. There were 3 complications: 2 intratumoral hematomas and 1 death due to hemorrhage. A survey of published CT biopsy series shows an overall success rate of 85%. The rate of serious complications is 3.5% (including 3 deaths). The incidence of intratumoral hematomas that are clinically silent or associated with relatively minor clinical problems is 9%. CT-guided intracranial biopsy is more reliable than the earlier freehand methods and simpler than stereotactic techniques. It is the procedure of choice for percutaneous biopsy of superficial and deep hemispheric lesions.

The multiple roles of Broca's discovery in the development of the modern neurosciences

Using the classical clinico-anatomical correlation method of the French clinical school, Paul Broca confirmed the localization of language in the frontal lobe. He actually discovered the lateralization of language in the left hemisphere. These contributions eventually led to the demise of the older concept of the sensorium commune, because Brocas ideas implied the presence of motor functions in the hemispheres. Although Broca worked within the theoretical motif of the faculty psychology, the reflex-oriented associationist psychology soon became the predominant theoretical framework of localization, because it accommodated the motor aspect of hemispheric function. Since Brocas time, the study of the biology of language has proceeded along two parallel but sometimes separate lines in the experimental and clinical traditions.

Catabolic effect of dexamethasone in patients with major head injuries.

In the records of our extensive metabolic studies on trauma victims, we found 16 head injured patients who had no other major injuries. Among them, nine had been given dexamethasone for at least 6 days. The other seven had not received any corticosteroids. There was no significant difference in the Glasgow Coma Scales of the treated and untreated groups. Metabolic balance studies were carried out for at least 3 days, including the periods when the treated patients were receiving dexamethasone. Mean nitrogen balance was -0.296 +/- 0.03 g/kg/day for the treated group and -0.182 +/- 0.03 g/kg/day for the untreated group. This difference was significant (p = 0.02, t-test). Our metabolic data are also consistent with those of other published studies, which used other corticosteroids and somewhat different methodologies. Thus, it is clearly established that corticosteroids cause significant degrees of catabolism in head injured patients, beyond what would normally be expected in such patients if they did not receive these drugs.

Computed tomography application to lumbar epidurography.

The application of current-generation computed tomography scanning to lumbar epidurography has resulted in a better appreciation of epidural anatomy and improved ease of interpretation of non-ionic contrast material within the epidural space. The development of extended window width has greatly improved imaging of the more variable levels of attenuation encountered in contrast material within the epidural space. The procedure of distribution of contrast material by catheter technique via the sacral canal approach is described. The experience obtained on examination of 24 patients is discussed, along with the possible adjunctive and primary roles of this type of imaging in evaluation of the lumbar spine.

Hughlings Jackson’s Theory of Localization and Compensation

Hughlings Jackson might well have objected to the title of this book, but not because he eschewed either theory or controversy. Rather, I think he would have taken issue with the implications of the word “recovery.” It seems to imply the theoretical possibility of complete recovery; this he denied, at least at the physiological level in adults. “Compensation,” on the other hand, implies that one part may substitute for another to a greater or lesser degree. This concept arose almost inevitably from the theoretical base that he constructed for all of modem neurology.

Computed tomography - guided intracranial biopsy and cyst aspiration: Accumulated experience in 60 patients

We have reviewed our continued experience with computed tomography guided freehand percutaneous brain biopsy using a needle guide sheath of our own devising. The guide sheath is equipped with small metallic marker beads and throws no artifacts. It is useful in demonstrating the exact tip of the guide biopsy sheath in relation to the wall of the intracerebral lesion. The deforming response of the target lesion wall to the guide sheath and the biopsy needle is easily seen using our technique and is highly correlated to obtaining a satisfactory pathologic specimen. Combination of this guide sheath with a suitable computed tomography compatible head frame may represent a highly accurate and reliable but relatively simple guidance system.