Image-guided spinal navigation.
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Bone Plates↗
Biomedical subjects
I H Kalfas
Publications and source records attributed to I H Kalfas.
Anterior thoracolumbar stabilization.
The options available for managing the unstable thoracolumbar spine are varied. Surgical stabilization from an anterior approach is indicated when there is a significant disruption of the load-bearing capacity of the vertebral body. The development of spinal fixation devices for the anterior thoracolumbar spine has facilitated the acceptance of this approach and has made it a versatile management option for a variety of disorders involving this region of the spine.
Humans↗
Antibiotic penetration into cervical discs.
Antibiotics are frequently prophylactically administered in surgical procedures to reduce the incidence of infection. The penetration of antibiotics into lumbar discs has been studied with mixed results, but penetration into cervical discs has not been reviewed. In this study, we examined the penetration of two commonly used antibiotics, oxacillin and cefazolin, into cervical discs. Eighteen patients with a total of 30 discs removed were studied. Two groups, each consisting of four patients with five discs removed, received either 1 g of oxacillin or 1 g of cefazolin by a single, preoperative intravenous infusion. Two other groups, each consisting of five patients with 10 discs removed, received either 2 g of oxacillin or 2 g of cefazolin, also by a single, preoperative intravenous infusion. A blood specimen, from which serum antibiotic levels were determined, was obtained from each patient simultaneously with each discectomy. The time interval between the antibiotic infusion and discectomy/phlebotomy was also recorded. Antibiotic levels were detected in all discs removed but were quantifiable in only 12. Nine of these 12 had been exposed to cefazolin. Of these nine discs, one was from a patient who had received 1 g whereas the other eight were from patients who had received 2 g of cefazolin. This represents 80% of the removed discs exposed to 2 g of cefazolin (10 discs total) and 20% exposed to 1 g (5 discs total). The remaining three discs with quantifiable antibiotic levels had been exposed to 2 g of oxacillin, which represents 30% of the discs (10 total) exposed to that dose of oxacillin. Although cervical disc space infections are rare, they are serious.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Application of frameless stereotaxy to pedicle screw fixation of the spine.
Interactive frameless stereotaxy has been successfully applied to intracranial surgery. It has contributed to the improved localization of deep-seated brain lesions and has demonstrated a potential for reducing both operative time and morbidity. However, it has not been as effectively applied to spinal surgery. The authors describe the application of frameless stereotactic techniques to spinal surgery, specifically pedicle screw fixation of the lumbosacral spine. Preoperative axial computerized tomography (CT) images of the appropriate spinal segments are obtained and loaded onto a high-speed graphics supercomputer workstation. Intraoperatively, these images can be linked to the appropriate spinal anatomy by a sonic localization digitizer device that is interfaced with the computer workstation. This permits the surgeon to place a pointing device (sonic wand) on any exposed spinal bone landmark in the operative field and obtain multiplanar reconstructed CT images projected in near-real time on the workstation screen. The images can be manipulated to assist the surgeon in determining the proper entry point for a pedicle screw as well as defining the appropriate trajectory in the axial and sagittal planes. It can also define the correct screw length and diameter for each pedicle to be instrumented. The authors applied this device to the insertion of 150 screws into the lumbosacral spines of 30 patients. One hundred forty-nine screws were assessed to be satisfactorily placed by postoperative CT and plain film radiography. In this report the authors discuss their use of this device in the clinical setting and review their preliminary results of frameless stereotaxy applied to spinal surgery. On the basis of their findings, the authors conclude that frameless stereotactic technology can be successfully applied to spinal surgery.
Adolescent↗
Cervical spine stabilization. Surgical techniques.
Because of the virtually unlimited combination of injuries and disorders that can affect the cervical spine, no single stabilizing procedure can be advocated for all situations. As our understanding in the areas of spinal biomechanics, bone graft properties, internal fixation devices, and external immobilization has improved, advances have been made in the surgical stabilization of the cervical spine. These innovations are not necessarily intended to replace those proven methods that have been traditionally employed, but rather add to the armamentarium of available stabilizing techniques. With this broader selection of techniques, managing patients with an unstable cervical spine can be even more individualized in order to achieve an optimal outcome.
Cervical Vertebrae↗
Changes in the cervical foraminal area after anterior discectomy with and without a graft.
A controversial point in the management of patients undergoing anterior cervical discectomy is whether an interbody bone graft should be used. Proponents of interbody grafting claim that without a graft, the disc height and the area of the foramina at that level will decrease postoperatively with the potential for persistent symptoms and/or the development of a radiculopathy. Using a two-dimensional digital planimeter, we measured the cross-sectional area (cm2) of cervical foramina on preoperative and postoperative oblique films in patients undergoing anterior cervical discectomy. Group A patients underwent the insertion of an interbody graft after the discectomy; Group B patients did not. Our results indicate that in all the patients in Group A, there was a statistically significant increase in the area of the foramina (P < 0.001) and in Group B, a statistically significant decrease (P = 0.0005). However, when the absolute change in magnitude of the foramina was measured, without respect to an increase or decrease, there was no statistically significant difference (P > 0.8). There was no statistically significant difference (P = 1.000) in the outcome between the two groups. From an anatomical standpoint, our data support the insertion of an interbody graft if the surgeon wishes to increase the area of the foramen. However, the overall magnitude of change is not significant, which may be a factor in why the clinical outcome is similar in both groups.
Adult↗
Postoperative hemorrhage: a survey of 4992 intracranial procedures.
A series of 4992 intracranial procedures performed over an 11-year period was evaluated for the occurrence of postoperative hemorrhage. Forty patients (0.8%) experienced postoperative hemorrhage. Twenty-four hemorrhages were intracerebral (60%), 11 were epidural (28%), 3 were subdural (7.5%), and 2 were intrasellar (5.0%). Hematomas in 33 patients occurred at the operative site, and 7 occurred remote from the operative site. Intracranial tumor was the reason for operation in 56% of the patients developing a clot, and meningioma was the most common tumor associated with this complication. The use of the sitting position was not associated with an increased incidence of postoperative hemorrhage. Disturbances of coagulation and hypertension seemed to be potential precipitating factors. Postoperative hemorrhage was recognized within 12 hours of operation in 35% of the patients. An altered level of consciousness was the most frequent clinical finding, present in all patients. There was no clear relationship between the time of recognition and the final clinical outcome. Parenchymal clots carried the worst prognosis, accounting for 8 of the 11 deaths and all 7 patients with poor neurological outcome.
Adolescent↗
Symptomatic subependymoma in a 14-year-old girl, diagnosed by NMR scan.
Symptomatic subependymomas in the pediatric age group are rare. A 14-year-old girl with a IV ventricle subependymoma is described. She had a 2-month history of progressive headache, neck stiffness and nausea. Computed tomography revealed hydrocephalus for which a ventriculoperitoneal shunt was inserted. A nuclear magnetic resonance (NMR) scan later displayed a mass lesion in the roof of the IV ventricle. A suboccipital craniectomy was performed with total excision of a subependymoma.
Adolescent↗
Cervical neurenteric cyst associated with Klippel-Feil syndrome: a case report and review of the literature.
A neurenteric cyst of the spine is a rare congenital disorder secondary to alimentary duplication and vertebral malformation. It should, however, be included in the differential diagnosis of an intradural, extramedullary spinal lesion. We present a case of a cervical neurenteric cyst associated with Klippel-Feil syndrome and discuss the clinical, radiologic, histopathologic, immunohistochemical and embryologic characteristics of this disorder.
Adult↗