Medical complications of head injury.

There are many common and significant medical complications of head injury. These include (1) cardiovascular problems such as hyperdynamic state, myocardial injury, and dysrhythmias; (2) respiratory changes such as neurogenic pulmonary edema, hypoxia, abnormal ventilatory patterns, pulmonary infections, and pulmonary emboli secondary to deep vein thrombosis; (3) consumption coagulopathy; (4) water and electrolyte derangements--hypo- and hypernatremia; (5) hypothalamic/pituitary dysfunction--syndrome of inappropriate secretion of antidiuretic hormone and diabetes insipidus; (6) increased general metabolism with loss of immunocompetence, respiratory compromise, and complications of decreased activity; (7) gastrointestinal difficulties, particularly stress gastritis; and (8) infectious problems including those related to contamination from open wounds and foreign bodies such as monitors.

Is there a superior occipitofrontal fasciculus? A microsurgical anatomic study.

OBJECTIVE: Using a fiber-dissection technique, our aim was to expose and study the myelinated fiber bundles of the brain to achieve a clearer conception of their configurations and locations. During the course of our study, the superior occipitofrontal fasciculus became the focus of our interest. Many publications have defined this as a bundle of association fibers, located between the corpus callosum and the caudate nucleus, that connects the frontal and occipital lobes. By examining this area using fiber dissection, we realized that the descriptions of the anatomy are inadequate; thus, we focused on the elucidation of the anatomic structures of this region and, in particular, that known as the superior occipitofrontal fasciculus. METHODS: Twenty previously frozen, formalin-fixed human brains were dissected under the operating microscope using the fiber-dissection technique. RESULTS: On coronal sections of the brain, a structure on the superolateral aspect of the caudate nucleus usually has been identified as the superior occipitofrontal fasciculus. However, our fiber dissections revealed that this structure is the superior thalamic peduncle, that it is composed of projection fibers rather than association fibers, and that it does not interconnect the occipital and frontal lobes. CONCLUSION: The structures of the brain are better understood when the fiber-dissection technique is used to explore their configurations and locations. The resulting information is especially beneficial for planning strategies and tactics of neurosurgical procedures.

Postoperative magnetic resonance imaging with titanium implants of the thoracic and lumbar spine.

Within recent years, the technologies of radiological imaging and spinal instrumentation have exponentially increased. New methods of preoperative imaging, that is, magnetic resonance imaging (MRI) and computed tomography, have allowed for a better understanding of surgical pathology. Such an understanding is likely to lead to a more successful surgical experience, which certainly is the case with spine surgery with instrumentation. However, after implantation of most instrumentation, imaging is greatly impaired. Metallurgic advancements in titanium were sought to reduce postoperative imaging problems. The purpose of this study is to assess the presence and extent of artifacts seen on postoperative MRI scans in patients with titanium spinal implants. Six patients, four with degenerative spine disease and two with neoplasms, had thoracic and/or lumbar spinal fixation performed with titanium instrumentation. All patients underwent postoperative conventional MRI with the use of T1-weighted, T2-weighted, and gradient-echo sequences. The scans and individual sequences were then analyzed for image quality. A progressive and significant increase in imaging artifact related to the titanium spinal instrumentation was observed on the T1-weighted, T2-weighted, and gradient-echo sequences. Titanium spinal instruments do not allow optimal postoperative imaging on conventional MRI scanners.

Surgical anatomy of the anterior cervical spine: the disc space, vertebral artery, and associated bony structures.

OBJECTIVE: To elucidate the relationships between the neurovascular structures and surrounding bone, which are hidden from the surgeon by soft tissue, and to aid in avoiding nerve root and vertebral artery injury in anterior cervical spine surgery. METHODS: Using six cadaveric spines, we measured important landmarks on the anterior surface of the spine, the bony housing protecting the neurovascular structures in the lateral disc space, and the changes that occur during the discectomy with interbody distraction of the vertebral bodies. The measurements included the distance between the medial borders of the longus colli muscle at the level of each interspace; the width and height of each disc space at the midline; the width and height of the costal process; the distances between the cranial tip of the uncinate process (UP) and the vertebral body (VB) above and from the tip of the UP to the vertebral artery; the anteroposterior diameter or the extent of the disc spaces in the midline; the height at the midpoint of the distracted disc space; the UP-VB distance in distraction; and the width of the visible nerve root. RESULTS: The distance between the medial borders of the longus colli muscles increased in a rostral to caudal direction. The height of the UP was shortest at C4-C5 and greatest at C5-C6; the width was narrowest at C4-C5 and widest at C6-C7. The width of the costal process measured from the VB to the anterior tubercle was narrowest at C2-C3 and widest at C6-C7. The midpoint height of the costal process was smallest at C6-C7 and tallest at C4-C5 and C5-C6. The nondistracted UP-vertebral artery distance was the shortest at C2-C3 and longest at C4-C5. The nondistracted UP-VB distance averaged 1 mm at C2-C3 and C6-C7 and 1.5 mm at C4-C5. The height of the distracted disc space was shortest at C2-C3 and C6-C7. The UP-VB distance after distraction was greatest at C4-C5. Only at the C2-C3 interspace was the nerve always above the process. The vertebral artery entered the foramen transversarium of C6 in all the specimens. CONCLUSION: Although avoiding unfortunate injury is not always possible, understanding the locations and relations among the anatomic features is the only safeguard against unwarranted damage.

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.

Identification of a retained surgical sponge using magnetic resonance imaging.

We report a patient who had a spinal abscess due to a retained surgical sponge. Through the use of magnetic resonance imaging, the sponge was identified. Postoperative foreign body complications are discussed.

Pitfalls and successes of peer review in neurosurgery.

As the first editor of the Journal of Neurosurgery, Louise Eisenhardt, acting with the advice of the editorial board, was responsible for making decisions on the acceptance or rejection of submitted manuscripts. Her log, covering the first 14 years of editorial decisions, is a record of neurosurgical progress and of the forces--scientific, technical and other--that shaped the field of neurosurgery. Any peer-review process is subject to pitfalls that become evident in retrospect, but an effective peer-review process is one of the basic ingredients of scientific progress. The decisions to accept or reject manuscripts submitted to the Journal of Neurosurgery during Eisenhardt's tenure are highlighted in this historical vignette.

Quadrant anatomy of the articular pillars (lateral cervical mass) of the cervical spine.

Knowledge of the relevant anatomy is important when developing a strategy for introducing screws into the lateral masses to secure internal fixation devices. This paper defines key bony landmarks and their relationship to critical neurovascular structures and identifies a location for safe placement of cervical articular pillar (lateral mass) screws. Measurements of anatomical landmarks in 10 spines from human cadavers aged 61 to 85 years were made by caliper and a metric ruler. Landmarks were the lateral facet line, rostrocaudal line, medial facet line, intrafacet line, and medial facet line-vertebral artery line. The average distances and ranges were recorded. Such great variance existed in measurements from spine to spine and within the same spine as to render averages clinically unreliable. Dissection revealed that division of the articular pillar into four quadrants leaves one, the superior lateral quadrant, under which there are no neurovascular structures; this may be considered the "safe quadrant" for placement of posterior screws and plates.

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.

The suboccipital cavernous sinus.

The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures. Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope. This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous-cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the "suboccipital cavernous sinus." Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed.

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.

Inside-outside technique for posterior occipitocervical spine instrumentation and stabilization: preliminary results.

OBJECT: The authors present a series of 16 patients who underwent inside-outside occipital and posterior cervical spine stabilization. METHODS: In this technique, the screw was placed from the inside of the occiput to the outside. An articular (lateral) mass plate was contoured to the shape of the occipital bone and the cervical spine and affixed to the occiput with a flat-headed screw or stud placed through a burr hole in the calvaria with the flat head of the screw in the epidural space and the threads facing outward. The bone plate was then secured with a nut to the occipital screw and the cervical plate was attached to the spine with a bone screw that coursed through the plate and into the articular pillar. Our series included six children and 10 adults. In five patients, previous fusion had failed; in two patients spinal instability was secondary to Down's syndrome; two patients' instability was related to developmental anomalies; and in five patients spinal instability was due to the presence of tumor. One patient with rheumatoid arthritis had undergone a transoral procedure. Two patients had suffered traumatic fracture. Three patients died of causes unrelated to the procedure, one patient died of metastatic cancer, and one patient died in a long term care facility of cardiopulmonary complications. One patient with renal failure suffered a hemorrhage from an arteriovenous fistula after being treated with dialysis. In one child, a nut backed off after 3 months. The nut was reseated, and a maturing arthrodesis was present. CONCLUSIONS: The authors conclude that the inside-outside occipitocervical fixation is an effective technique for stabilizing the cervical spine.

The transcondylar approach to extradural nonneoplastic lesions of the craniovertebral junction.

Ventral extradural lesions at the craniovertebral junction are commonly exposed through the transoral or transmaxillary approach. The disadvantages of these approaches include: 1) difficulty in reaching laterally located lesions; 2) ineligibility of patients with an intradental distance of less than 25 mm or severe macroglossia; 3) the need for a separate procedure for stabilization and fusion; and 4) the risk of infection from transgressing a contaminated field. In this report, the authors describe the use of the transcondylar approach to extradural nonneoplastic lesions of the anterior craniovertebral junction for decompression and stabilization. Advantages of this approach include: 1) a short distance to the lesion; 2) a wide surgical envelope; 3) direct visualization of the dural sac, eliminating manipulation of the brainstem or upper spinal cord; 4) easy identification and control of the ipsilateral vertebral artery; 5) direct visualization and preservation of the lower cranial nerves; and 6) a sterile field. In addition, occipitocervical fusion and instrumentation can be performed during the same procedure. The transcondylar approach, based on anatomical studies in cadavers, was used to treat eight patients with ventral nonneoplastic lesions at the craniocervical junction. The technique and results are described.

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.

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.

Herophilus of Alexandria (325-255 B. C.). The father of anatomy.

Herophilus (325-255 B. C.) is one of the group that has been called the great Greek physicians. All members of this group lived during the last 400 years of Greek intellectual leadership and the first 200 years of Roman domination. Herophilus was born in the Greek town of Chalcedon. He received his medical training under Praxagoras, a famous physician and anatomist who taught at the Hippocratean medical school on the island of Cos (Kos). He moved to Alexandria, Egypt, as a young man and lived there for the rest of his life. With his younger contemporary, Erasistratus, he did the first ever scientific human cadaveric dissections for a short period of no more than 30-40 years. Human dissection then was forbidden and was not allowed again for 1800 years. It seems that only these two physicians ever performed human dissection until the Renaissance, around 1530 A. D. The anatomic and physiologic discoveries of Herophilus were phenomenal. As Hippocrates is called the Father of Medicine, Herophilus is called the Father of Anatomy. Most would argue that he was the greatest anatomist of antiquity and perhaps of all time. The only person who might challenge him in this assessment is Vesalius, who worked during the 16th century A. D.

The anterior extrapleural approach to the thoracolumbar junction revisited.

General surgeons often provide the exposure for the anterior repair of vertebral body lesions. The standard anterior approach to the thoracolumbar junction (T11-L1) is a transpleural 9th or 10th rib thoracoabdominal incision. From October 1995 through March 1997, 22 patients underwent anterior repair of thoracolumbar junction vertebral lesions through an alternative 11th rib resection while maintaining an extrapleural approach. Exposure was excellent, as judged by the neurosurgical team completing the repairs. Chest tubes were not used routinely, and all patients healed without complications. A major limitation of the 11th rib extrapleural approach to the thoracolumbar junction has been poor exposure. This problem is eliminated with the use of an abdominal self-retaining retractor system. With many potential advantages to this 11th rib exposure (less pain, fewer pulmonary problems, and better wound healing), we consider the 11th rib incision to be the approach of choice to the thoracolumbar junction and recommend renewed interest in this incision.

"General surgical pearls" for the anterior exposure of vertebral fractures.

Recently interest has been increasing in the anterior surgical approach for spinal cord decompression and bony stabilization of vertebral compression fractures. Our neurosurgical spine service routinely consults us to provide anterior operative exposure and wound closure for all levels of the thoracic and lumbar vertebral spine. Averaging about 30 exposures per year we have developed an excellent operative experience with these vertebral exposures. With no complete general surgery reference on anterior vertebral identified this summary of our "general surgical pearls" that we have learned and/or have developed should significantly aid other general and trauma surgeons who may be asked by their neurosurgical and/or orthopedic surgical colleagues for assistance with these operations.

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.

Muscle and musculocutaneous flap coverage of exposed spinal fusion devices.

Midline wound dehiscence in the back with exposure of spinal stabilization devices remains a challenging problem, mainly in the presence of infection. Usually, the treatment consists of instrumentation removal, wound debridement, and antibiotic therapy. These can result in instability of the spine and significantly prolong the hospitalization. The use of muscle and musculocutaneous flaps provides excellent soft-tissue coverage, obliterates the dead space, controls the infection, and creates conditions to salvage the hardware. Eight cases of spinal rod instrumentation, complicated by wound infection and dehiscence, have been treated successfully with single or multiple muscles and musculocutaneous flaps. Our method of treatment for these complex wounds, in two institutions, is discussed.