Search PubMed⌕ Search

Biomedical subjects

T G Pait

Publications and source records attributed to T G Pait.

26 records · Page 2Linked to original sources

The history of the neurosurgical engine.

The opening of the skull of a living human being dates back to early civilization. The procedure may have been performed as early as the Neolithic period. Surgeons have continued to search for a better, easier, quicker, and safer method to open the skull. Today, most neurosurgeons are well acquainted with the surgical drill; however, few are familiar with the development of this instrument from its beginnings in dentistry to its use in modern neurosurgery. As cerebral localization advanced in the late 19th century, so, too, did the demands for better techniques for entering the cranial cavity and exposing more extensive areas of the brain. Mechanical devices began to appear in operating theaters throughout the world. Despite the enthusiasm of its inventors, the surgical engine was used by but a few pioneer cranial surgeons. The use of a surgical engine in the operating room has become commonplace. Its presence continues to demand respect. There is no doubt that this instrument has helped advance neurosurgery. Its development and refinement are rich in history and closely parallel the development of modern neurosurgery.

History, 18th Century↗

Updated assessment and current classification of spinal meningeal cysts.

The classification of spinal meningeal cysts (MC's) in the literature is indistinct, confusing, and in certain categories histologically misleading. Based on a series of 22 cases, the authors propose a classification comprising three categories: spinal extradural MC's without spinal nerve root fibers (Type I); spinal extradural MC's with spinal nerve root fibers (Type II); and spinal intradural MC's (Type III). Although water-soluble myelography may disclose a filling defect for all three categories, computerized tomographic myelography (CTM) is essential to reveal communication between the cyst and the subarachnoid space. Communication demonstrated by CTM allows accurate diagnosis of a spinal MC and rules out other mass lesions. Magnetic resonance imaging appears useful as an initial study to identify an intraspinal cystic mass. Final characterization is based on operative inspection and histological examination for all three categories.

Adolescent↗

The cutting-edge microvascular needle. A scanning electron microscopic study.

The authors have compared the vascular endothelial damage caused by blunt-tipped microvascular needles as reported previously with that of sharp cutting-edged needles of comparable size. The same four distinct vascular lesions were found with cutting-edged needles as with the blunt-tipped needles. Even though one experimenter made all of the lesions, and all of the tissue was handled in the same fashion, there was much variation in the extent of the intimal damage. Overall, cutting-edged needles produced slightly less intimal tearing and platelet aggregation than blunt-tipped needles, but the difference was not striking.

Animals↗

Scanning electron micrographic study of vascular lesions caused by microvascular needles and suture.

The authors studied the damage to blood vessels 1 to 2 mm in diameter caused by the most commonly used types of microvascular needle. Excluding variables introduced by anastomosis, the study focused specifically on lesions attributable only to the needle and suture. Scanning electron microscopy revealed four distinct types of lesion. A theory is proposed to explain the mechanisms whereby these lesions were produced, and a needle design is recommended that may aid in minimizing vascular trauma.

Animals↗

Microsurgical exposure of the petrous portion of the carotid artery.

Occlusion of the cervical portion of the internal carotid artery (ICA) has been treated by vein graft bypass from the common carotid to the supraclinoid segment. However, this procedure has the disadvantages of requiring temporary occlusion of collateral flow, the short length of ICA available for anastomosis, and the retraction required for exposure of the supraclinoid area. In an attempt to find a more suitable bypass site for grafting, the petrous portion of 50 carotid arteries was studied in cadavers. It was found that there was a 1-cm length of the horizontal segment of the petrous carotid that could be exposed in the floor of the middle fossa lateral to the trigeminal nerve. This segment was covered by dura only or a thin layer of cartilage in approximately half of the specimens. In the remainder, there was often a thin shell of bone covering the artery, which could be drilled away. The petrous portion of the carotid artery had branches in only 38% of specimens, a Vidian branch in 30%, and a periosteal branch in 8%. The carotico-tympanic artery, previously reported to be the most common branch, was not found in a single case. These branches allow the retrograde flow needed to maintain the patency of this segment following proximal occlusions. The relationship of the carotid artery to structures include the cochlea, middle ear, Eustachian tube, tensor tympani muscle, geniculate ganglion, and facial, greater petrosal, and trigminal nerves.

Carotid Artery, Internal↗

Microsurgical anatomy and dissection of the temporal bone.

The topographic and internal anatomy of the temporal bone is reviewed with emphasis on the relationships important to the suboccipital, middle fossa and translabyrinthine surgical approaches to the internal auditory canal. The equipment and materials needed for temporal bone dissection in the laboratory are reviewed. A stepwise method of dissection for each of the three surgical approaches to the internal acoustic meatus is outlined for both the dry and wet temporal bone.

Humans↗