http://xoomer.virgilio.it/lusebra/NuoviFile/PrevenzioneTVP.pdf

Prevention of venous thromboembolism

Prevention of Venous Thromboembolism : The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

We performed magnetic resonance imaging on sixty-seven individuals who had never had low-back pain, sciatica, or neurogenic claudication. The scans were interpreted independently by three neuro-radiologists who had no knowledge about the presence or absence of clinical symptoms in the subjects. About one-third of the subjects were found to have a substantial abnormality. Of those who were less than sixty years old, 20 per cent had a herniated nucleus pulposus and one had spinal stenosis. In the group that was sixty years old or older, the findings were abnormal on about 57 per cent of the scans: 36 per cent of the subjects had a herniated nucleus pulposus and 21 per cent had spinal stenosis. There was degeneration or bulging of a disc at at least one lumbar level in 35 per cent of the subjects between twenty and thirty-nine years old and in all but one of the sixty to eighty-year-old subjects. In view of these findings in asymptomatic subjects, we concluded that abnormalities on magnetic resonance images must be strictly correlated with age and any clinical signs and symptoms before operative treatment is contemplated.

Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. A prospective investigation

Tumors and tumorous conditions of the bones and joints

We performed magnetic resonance im- aging on sixty-seven individuals who had never had low- back pain, sciatica, or neurogenic claudication. The scans were interpreted independently by three neuro- radiologists who had no knowledge about the presence or absence of clinical symptoms in the subjects. About one-third of the subjects were found to have a substantial abnormality. Of those who were less than sixty years old, 20 per cent had a herniated nucleus pulposus and one had spinal stenosis. In the group that was sixty years old or older, the findings were abnormal on about 57 per cent of the scans: 36 per cent of the subjects had a herniated nucleus pulposus and 21 per cent had spinal stenosis. There was degeneration or bulging of a disc at at least one lumbar level in 35 per cent of the subjects between twenty and thirty-nine years old and in all but one of the sixty to eighty-year-old subjects. In view of these findings in asymptomatic subjects, we concluded that abnormalities on magnetic resonance images must be strictly correlated with age and any clinical signs and symptoms before operative treatment is contemplated.

https://smhs.gwu.edu/orthopaedic-surgery/sites/orthopaedic-surgery/files/Boden%20Lumbar%20Disk.pdf

Abnormal Magnetic-Resonance Scans of the Lumbar Spine in Asymptomatic Subjects

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.

Application of frameless stereotaxy to pedicle screw fixation of the spine

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.

https://www.ajronline.org/doi/pdfplus/10.2214/ajr.147.4.757

Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography

Object. Despite a history of safety and efficacy, spinal anesthesia is rarely used in lumbar surgery. Application of regional anesthetics is widely preferred for lower-extremity surgery, but general anesthesia is used almost exclusively in spine surgery, despite evidence that spinal anesthesia is as safe and may offer some advantages. Methods. In this case-controlled study the authors analyzed outcomes obtained in 400 patients in whom either spinal anesthesia or general anesthesia was induced to perform a lumbar decompression. Patients were matched for anesthesia-related class, preoperative diagnosis, surgical procedure, and perioperative protocols. All aspects of surgery, recovery, postanesthesia care, and pain management were uniform irrespective of the anesthetic type. Case complexity was equivalent. An independent observer performed analysis of the data. Data from the intraoperative period through hospital discharge were collected and compared. Two hundred consecutive patients meeting inclusion criter...

Comparison of spinal and general anesthesia in lumbar laminectomy surgery: a case-controlled analysis of 400 patients.

Spinal anesthesia for elective lumbar spine surgery

Study design A case-controlled, comparative study of 400 patients undergoing lumbar surgery, treated with either spinal or general anesthesia. An independent observer analyzed outcomes. Objectives To determine the rate and type, of perioperative complications associated with each anesthetic method among lumbar surgery patients. Summary of background data Spinal anesthesia is infrequently used for spinal procedures. While complications associated with spinal anesthesia are rare, some authors have suggested that spinal anesthesia may exacerbate existing neurologic disease and have recommended against its use in lumbar disc surgery. Others have found the technique safe and effective. General anesthesia may be preferred because it is seen as the routine accepted practice, because of greater patient acceptance and the ability to perform longer operations, or because of a general sense that general anesthesia is "safer" in these procedures. Methods Patients treated between 1994 and 1998 were matched for anesthetic class, preoperative diagnosis, surgical procedure, and perioperative protocols. All patients were treated according to a uniform protocol and recovered in the same perianesthetic environment. Data from the intraoperative period through hospital discharge were collected and compared. Results A total of 200 patients were included in each group. Overall complication rates and time to discharge were significantly lower in spinal anesthetic patients. Total anesthetic and operative times were significantly longer for general anesthetic patients, and perioperative heart rate and mean arterial pressures were elevated compared with those in spinal anesthetic patients. Nausea, requirements for antiemetic medication, and the incidence of urinary retention were significantly increased among general anesthesia patients. Spinal anesthesia patients had fewer spinal headaches compared with the general anesthetic group, but statistical significance was not obtained. Conclusions For patients undergoing decompressive lumbar surgery, spinal anesthesia is at least comparable to general anesthetic with respect to complications. Specific advantages to spinal anesthesia include decreased nausea and antiemetic requirements, reduced analgesic requirements, and reduced overall complication rate.

Gordon R. Bell

Papers

Application of frameless stereotaxy to pedicle screw fixation of the spine

Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography

Comparison of spinal and general anesthesia in lumbar laminectomy surgery: a case-controlled analysis of 400 patients.

Spinal anesthesia for elective lumbar spine surgery

Complications associated with lumbar laminectomy: a comparison of spinal versus general anesthesia.