Positive association of free triiodothyronine with pancreatic ß-cell function in people with prediabetes.

AIM: To analyse the effects of thyroid hormones on ß-cell function and glucose metabolism in people with prediabetes who are euthyroid. METHODS: A total of 111 people who were euthyroid underwent 75-g oral glucose tolerance tests, of whom 52 were assigned to the normal glucose tolerance and 59 to the prediabetes groups. Homeostatic model assessment of ß-cell function, insulinogenic index and areas under the curve for insulin and glucose were evaluated as indices of pancreatic ß-cell function. RESULTS: In both groups, BMI, fasting insulin, homeostasis model assessment ratio and HDL cholesterol correlated significantly with all indices of pancreatic ß-cell function. Free triiodothyronine correlated positively with all insulin secretion indices in the prediabetes group. Multiple linear regression analysis showed that free triiodothyronine was an independent variable that had a positive correlation with all indices of ß-cell function in the prediabetes group. By contrast, no such correlation was found in the normal glucose tolerance group. CONCLUSIONS: Free triiodothyronine is associated with both basal and glucose-stimulated insulin secretion in people with prediabetes who are euthyroid; therefore, the regulation of insulin secretion by thyroid hormones is a potentially novel therapeutic target for the treatment of diabetes.

Secondary medulla oblongata involvement following middle cervical spinal cord injury associated with latent traumatic instability in a patient with ossification of the posterior longitudinal ligament.

STUDY DESIGN: A case report. OBJECTIVES: To report a rare case of extension of edema and hemorrhage from initial C4-5 spinal injury to the medulla oblongata. SETTING: Center for Spinal Disorders and Injuries, Bibai Rosai Hospital, Japan. METHODS: A 68-year-old man with ossification of the posterior longitudinal ligament (OPLL) had sustained tetraplegia after tumbling over a stone. Initially, the patient was diagnosed with an acute C4-5 spinal cord injury without radiological abnormalities and was treated conservatively. At 7 h after the injury, the patient had an ascending neurological deficit, which required respiratory assistance. Magnetic resonance imaging revealed a marked swelling of the spinal cord above C4-5 extending to the medulla oblongata. RESULTS: Retrospective radiological assessment revealed that the spine was unstable at the injury level because of discontinuities in both anterior and posterior longitudinal ligaments. There was also signal intensity change within the retropharyngeal space at the C4-5 intervertebral disc. This injured segment was highly vulnerable to post-injury dynamic stenosis and easily sustained secondary neural damage. CONCLUSIONS: This case report emphasizes a careful radiological assessment of latent structural instability in patients with OPLL in order to detect and prevent deteriorative change in the spinal cord.

Role of MR imaging in the evaluation of low back pain (orthopedic surgeon's view).

In this article, the role of magnetic resonance imaging in the evaluation of degenerative lumbar disorders causing low back pain and radicular symptoms is discussed from an orthopedic surgeon's point of view. Magnetic resonance imaging can represent not only morphological, but pathological changes of osteoligamentous and neural components of the lumbar spine.

Tailgut cyst invaded by rectal cancer through an anal fistula: report of a case.

Rectal cancer accompanying or developing in a tailgut cyst has been reported. However, there have been no reports of cases such as the present one, a tailgut cyst invaded by a rectal cancer.

Complications of pedicle screw fixation in reconstructive surgery of the cervical spine.

STUDY DESIGN: Retrospective evaluation of complications in 180 consecutive patients with cervical disorders who had been treated by using pedicle screw fixation systems. OBJECTIVES: To determine the risks associated with pedicle screw fixation in the cervical spine and to emphasize the importance of preoperative planning and surgical techniques in reducing the risks of this procedure. SUMMARY OF BACKGROUND DATA: Generally, pedicle screw fixation in the cervical spine has been considered too risky for the neurovascular structures. There have been several reports describing the complications of lateral mass screw-plate fixation. However, no studies have examined in detail the complications associated with cervical pedicle screw fixation. METHODS: One hundred eighty patients who underwent cervical reconstructive surgery using cervical pedicle screw fixation were reviewed to clarify the complications associated with the pedicle screw fixation procedure. Cervical disorders were spinal injuries in 70 patients and nontraumatic lesions in 110 patients. Seven hundred twelve screws were inserted into the cervical pedicles, and the locations of 669 screws were radiologically evaluated. RESULTS: Injury of the vertebral artery occurred in one patient. The bleeding was stopped by bone wax, and no neurologic complication developed after surgery. On computed tomographic (CT) scan, 45 screws (6.7%) were found to penetrate the pedicle, and 2 of 45 screws caused radiculopathy. Besides these three neurovascular complications directly attributed to screw insertion, radiculopathy caused by iatrogenic foraminal stenosis from excessive reduction of the translational deformity was observed in one patient. CONCLUSIONS: The incidence of the clinically significant complications caused by pedicle screw insertion was low. Complications associated with cervical pedicle screw fixation can be minimized by sufficient preoperative imaging studies of the pedicles and strict control of screw insertion. Pedicle screw fixation is a useful procedure for reconstruction of the cervical spine in various kinds of disorders and can be performed safely.

Correction of cervical kyphosis using pedicle screw fixation systems.

STUDY DESIGN: This retrospective study was conducted to analyze the clinical results in 30 patients with cervical kyphosis that had been treated using cervical pedicle screw fixation systems. OBJECTIVES: To evaluate the effectiveness of a pedicle screw fixation procedure in correction of cervical kyphosis. SUMMARY OF BACKGROUND DATA: Correction of cervical kyphosis is a challenging problem in the field of spinal surgery. There have been several reports regarding surgical correction of cervical kyphosis; however, there have been no detailed reports on correction of cervical kyphosis using a pedicle screw fixation procedure. METHODS: Thirty patients with cervical kyphosis underwent correction and fusion using cervical pedicle screw fixation. Seventeen of 30 patients with flexible kyphosis (Group I) were managed by a posterior procedure alone. The remaining 13 patients with rigid or fixed kyphosis (Group II) had a combined anterior and posterior procedure. RESULTS: The average preoperative cervical kyphosis of 29.4 degrees improved to 2.3 degrees after surgery and was 2.8 degrees at the final follow-up. In Group I patients, preoperative kyphosis of 28.4 degrees improved to 5.1 degrees at the final follow-up. In contrast, preoperative kyphosis of 30.8 degrees in Group II patients improved to 0.5 degree at the final follow-up. Solid fusion was achieved in all patients. There were two patients with transient nerve root complications related to pedicle screw instrumentation. CONCLUSION: Cervical kyphosis in 30 patients was effectively corrected using a pedicle screw fixation procedure with no serious complications. Flexible kyphosis with segmental motion can be satisfactorily corrected by a single posterior procedure using pedicle screw fixation. However, circumferential osteotomies combined with a posterior shortening procedure involving a pedicle screw system are required to achieve the best correction of fixed kyphosis by bony union. Cervical pedicle screw fixation is the most advantageous instrumentation in the correction of cervical kyphosis.

Risk factors and probability of vertebral body collapse in metastases of the thoracic and lumbar spine.

STUDY DESIGN: The associations between vertebral body collapse and the size or location of the metastatic lesions were analyzed statistically to estimate the critical point of collapse. OBJECTIVES: To determine risk factors for collapse, to estimate the predicted probability of collapse under various states of metastatic vertebral involvement, and to establish the criteria of impending collapse. SUMMARY OF BACKGROUND DATA: Pathologic vertebral collapse brings about severe pain and paralysis in patients with cancer. Prevention of collapse plays a significant role in maintaining or improving their quality of life. Because no previous study has clarified the critical point of vertebral collapse, however, the optimum timing for prophylactic treatment has been unclear. METHODS: The size and location of metastatic tumor from Th1 to L5 were evaluated radiologically for 100 thoracic and lumbar vertebrae with osteolytic lesions. The correlations between collapse and the following risk factors (x1-x4) were determined by means of a multivariate logistic regression model: x1, tumor size (the percentage of tumor occupancy in the vertebral body [% TO]); x2, pedicle destruction, x3, posterior element destruction; and x4, costovertebral joint destruction. RESULTS: Significant risk factors were costovertebral joint destruction (odds ratio, 10.17; P = 0.021) and tumor size (odds ratio of every 10% increment in %TO, 2.44; P = 0.032) in the thoracic region (Th1-Th10), whereas, tumor size (odds ratio of every 10% increment in %TO, 4.35; P = 0.002) and pedicle destruction (odds ratio, 297.08; P = 0.009) were main factors in the thoracolumbar and lumbar spine (Th10-L5). The criteria of impending collapse were: 50-60% involvement of the vertebral body with no destruction of other structures, or 25-30% involvement with costovertebral joint destruction in the thoracic spine; and 35-40% involvement of vertebral body, or 20-25% involvement with posterior elements destruction in thoracolumbar and lumbar spine. CONCLUSIONS: With respect to the timing and occurrence of vertebral collapse, there is a distinct discrepancy between the thoracic and thoracolumbar or lumbar spine. When a prophylactic treatment is required, the optimum timing and method of treatment should be selected according to the level and extent of the metastatic vertebral involvement.

Anterior decompression and stabilization with the Kaneda device for thoracolumbar burst fractures associated with neurological deficits.

One hundred and fifty consecutive patients who had a burst fracture of the thoracolumbar spine and associated neurological deficits were managed with a single-stage anterior spinal decompression, strut-grafting, and Kaneda spinal instrumentation. At a mean of eight years (range, five years to twelve years and eleven months) after the operation, radiographs showed successful fusion of the injured spinal segment in 140 patients (93 per cent). Ten patients had a pseudarthrosis, and all were managed successfully with posterior spinal instrumentation and a posterolateral arthrodesis. The percentage of the canal that was obstructed, as measured on computed tomography, improved from a preoperative mean of 47 per cent (range, 24 to 92 per cent) to a postoperative mean of 2 per cent (range, 0 to 8 per cent). Despite breakage of the Kaneda device in nine patients, removal of the implant was not necessary in any patient. None of the patients had iatrogenic neurological deficits. After the anterior decompression, the neurological function of 142 (95 per cent) of the 150 patients improved by at least one grade, as measured with a modification of the grading scale of Frankel et al. Fifty-six (72 per cent) of the seventy-eight patients who had preoperative paralysis or dysfunction of the bladder recovered completely. One hundred and twenty-five (96 per cent) of the 130 patients who were employed before the injury returned to work after the operation, and 112 (86 per cent) of them returned to their previous job without restrictions. We concluded that anterior decompression, strut-grafting, and fixation with the Kaneda device in patients who had a burst fracture of the thoracolumbar spine and associated neurological deficits yielded good radiographic and functional results.

Significance of Gd-DTPA-enhanced magnetic resonance imaging for lumbar disc herniation: the relationship between nerve root enhancement and clinical manifestations.

Gd-DTPA-enhanced magnetic resonance (MR) imaging can depict not only the morphology but also the pathological changes of a nerve root compressed by herniated disc. Enhanced MR imaging was performed on 115 patients treated surgically for lumbar disc herniation. Nerve root enhancement was seen in 39.1% of the patients preoperatively and in 58.7% postoperatively. Preoperative root enhancement reflects the radicular pain intensity rather than the degree of neurological deficits, whereas postoperative enhancement did not correlate with the radicular symptoms. Nerve root enhancement represents an intraneural edema in the affected nerve root. Enhanced MR imaging is a potential method for the identification of an affected nerve root in patients with a discrepancy between the level of disc herniation and neurological manifestations.

Transpedicular screw fixation for traumatic lesions of the middle and lower cervical spine: description of the techniques and preliminary report.

Thirteen patients with fractures and/or dislocations of the middle and lower cervical spine were treated by transpedicular screw fixation using the Steffee variable screw placement system. Postoperative immobilization was either not used or simplified to short-term use of a soft neck collar. Recovery of nerve function and correction of kyphotic and/or translational deformities were satisfactory. All patients had solid fusion without loss of correction at the latest follow-up. There were no neurovascular complications. It was concluded that transpedicular screw fixation is as strong a fixation procedure for the cervical spine as it is for the thoracic and lumbar spine. This surgical procedure is associated with some risks of major neurovascular injuries; however, safety is adequate if the procedure is performed by experienced surgeons using meticulous surgical techniques.

Monitoring the evolution of intramedullary lesions in cervical spinal cord injury. Qualitative and quantitative analysis with sequential MR imaging.

The evolution of intramedullary lesions following an acute spinal cord injury was monitored with sequential magnetic resonance (MR) imaging. Seven patients who had sustained cervical spinal cord injuries were followed up from the acute to the chronic phase of the cord injury. MR images were evaluated not only qualitatively but also quantitatively. All intramedullary lesions were quantitatively analysed by T2 values. In the qualitative analysis, the regions with hyperintensity on T2-weighted images and isointensity on T1-weighted images were consistent with the region of simple oedema or gliosis. The former gradually disappeared after the acute phase, whereas the latter remained until the chronic phase. The regions with hyperintensity on T2-weighted images and hypointensity on T1-weighted images may represent cysts filled with necrotic tissue or clear fluid, or necrosis. The evolution of these lesions was also able to be monitored quantitatively by T2 values.

MRI of wallerian degeneration of the injured spinal cord.

OBJECTIVE: We assessed the MR appearance of wallerian degeneration following spinal cord injury. MATERIALS AND METHODS: We retrospectively reviewed the MR examinations of 13 patients with spinal cord injury. Thirty-one MR examinations were performed at various time intervals (1 day to 4 years) following injury. RESULTS: High signal intensity was observed in six patients (11 examinations) at the level of the posterior columns cephalad to the primary injury site on T2-weighted and proton density-weighted imaging at 10 week to 12 month intervals postinjury. In these six patients the posterior column was involved at the primary injury site. CONCLUSION: The abnormal intensity cephalad to the injury site is thought to represent wallerian degeneration, which should be considered in the differential diagnoses of spinal intramedullary lesions.