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Biomedical subjects

P G Korovessis

Publications and source records attributed to P G Korovessis.

At least 19 recordsLinked to original sources
PubMed2001

Treatment of dysplastic and congenitally dislocated hips with the Zweymueller total hip prosthesis.

Uncemented Zweymueller total hip prostheses were implanted in 35 dysplastic or dislocated hips in 33 patients. Sixteen hips were dislocated and 19 hips were dysplastic; in 12 hips, an intertrochanteric or pelvic osteotomy was performed in early childhood. In all cases, the titanium screw socket was implanted at the level of the original cotyloid cavity. Osteotomy of the greater trochanter, shortening osteotomy, or roof acetabuloplasty were not performed. In cases in which the femoral cavity was too narrow for the Zweymueller stem, an anterolateral longitudinal window-shaped osteotomy was performed. In cases of severe dysplasia, cotyloid cavity bone grafts from the resected femoral head were placed medially to reinforce the acetabular bottom. Clinical and radiographic follow-up ranged from 3-8 years. Average Harris hip score improved from 47 points preoperatively to 86.2 points postoperatively. Complications included two primary anterior dislocations, two temporary femoral nerve pareses, and two deep vein thromboses. At longest follow-up evaluation, no revision was indicated in any of the hips. Satisfactory results in this series were attributed to careful patient selection, precise preoperative radiographic planning, and an operative technique that included implantation of the socket at the primary acetabulum and achievement of primary stability using press-fit fixation.

Adult↗
PubMed1998

Reciprocal angulation of vertebral bodies in the sagittal plane in an asymptomatic Greek population.

STUDY DESIGN: A prospective study conducted on several roentgenographic parameters of the standing sagittal profile of the spine in an asymptomatic Greek population. OBJECTIVES: To perform segmental analysis of the sagittal plane alignment of the normal thoracic, lumbar, and lumbosacral spines and to compare the findings with those derived from similar populations. SUMMARY OF BACKGROUND DATA: Until recently, little attention has been paid to the sagittal segmental alignment of the spine, and there are only a few studies (in French and American populations) in which radiographic analysis of sagittal spinal alignment is investigated. METHODS: Ninety-nine consecutive asymptomatic Greek volunteers (38 men, 61 women), an average age of 52.7 +/- 15 years old (range, 20-79 years), were included in this prospective study, on the basis of several inclusion criteria. These volunteers were divided into six distinct age groups. The radiologic parameters, which were measured (by Cobb's method) on the lateral standing roentgenograms of the whole spine were: thoracic kyphosis (T4-T12), lumbar lordosis (L1-L5), total lumbar lordosis (T12-S1), distal lumbar lordosis (L4-S1), sacral inclination (measured from the line drawn parallel along the back of the proximal sacrum and the vertical line), pelvic tilting, vertebral body inclination, and relative segmental inclination between pairs of adjacent vertebrae. RESULTS: Thoracic kyphosis and lumbar lordosis (T12-S1, L1-L5) were not gender related. Thoracic kyphosis increased with age (P < 0.001), the lumbar spine (L1-L5) gradually became less lordotic as the thoracic kyphosis increased (P < 0.003), and total lumbar lordosis was not age related. Sacral inclination correlated strongly with both thoracic kyphosis (P < 0.002) and L1-L5 lordosis (P < 0.001). Pelvic tilting correlated strongly with L1-L5 lordosis (P < 0.0075), but did not correlate with thoracic kyphosis and age. Vertebral body inclination showed a narrow variability in T6-T12 and in L4 and a wide variability in T4, T5, L1-L3, and S1. Distal lumbar lordosis represents the 68.6% of the total lumbar lordosis. CONCLUSIONS: In the results of this study, a reliable table of reference for roentgenographic parameters in the sagittal plane of the spine was established in an asymptomatic Greek population. The parameters are similar to those used in previous studies. Thus, these data should be considered in preoperative planning and postoperative evaluation of achieved correction during restoration procedures of the spine in the sagittal plane.

Adult↗
PubMed1998

Unrecognized laceration of main bronchus caused by fracture of the T6 vertebra.

We report on an extremely rare case of a 58-year-old male polytraumatized patient who sustained a bursting fracture of the T6 vertebral body associated with laceration of the posterior wall of the right main bronchus from the spiculae of the vertebral body fragments. The patient was on admission asymptomatic until he underwent an endotracheal anesthesia for stabilization of associated fractures of the extremities, when he developed acute respiratory disturbances. The opening of the bronchus was repaired via a thoracotomy, while the spine was successfully supported with a custom-made brace for 3 months. In the 3-year follow-up evaluation, the patient did well and suffered no complaints of the spine or lungs. Spine surgeons should be aware of this rare complication, which may accompany bursting fractures in the midthoracic spine. Laceration of the bronchus should be suspected when fragments of the vertebral body are dislocated far anteriorly.

Accidents, Traffic↗
PubMed1998

Evolution of disc degeneration in lumbar spine: a comparative histological study between herniated and postmortem retrieved disc specimens.

This is a prospective comparative histological study on blood supply between lumbar herniated discs and postmortem retrieved ones. The aim of this study is to observe the evolution of disc degeneration in relation to its blood supply changes. Disc vascularization is present early in life, but the nucleus pulposus becomes avascular after adolescence. Vascularization of the annulus fibrosus (AF) probably also occurs late in life in association with degenerative changes and in response to trauma. Capillary neoformation and hypervascularity in degenerated discs have also been mentioned, based on animal cases. In the present study, intervertebral lumbar disc specimens were surgically removed from 84 patients with an average age of 41 years (range 24-60 years) operated on for disc herniation. In addition, control autopsy specimens were selected from 24 cadavera with an age of 39 years (range 24th gestation week to 80 years). The material was fixed in neutral buffered formalin, and 4-microm-thick sections were stained with hematoxylin-eosin and reticulin. In addition, with use of an immunohistochemical avidin-biotin complex technique, paraffin sections were stained for Ulex europaeus agglutinin receptors (UEA-1) after binding UEA-1 to the tissue. In surgical specimens, small blood vessels were identified in 45% of the disc cases. They were of the capillary-type vessels and were intermingled with proliferating endothelial cells, fibroblasts, and few mononuclear cells. All of them were located along the edges of the surgically retrieved fibrocartilage fragments. Sometimes thin bands of fibrin were attached to them and extravasated erythrocytes were occasionally seen. In autopsy specimens, blood vessels were identified in 78% of the retrieved discs. In contrast to the edge neovascularity observed in surgical specimens, capillaries were observed at the outer layer of AF surrounded by dense hyalinized and inactive-appearing collagen. From these results it is concluded that the blood vessels in extruded tissue from every type of herniation are newly formed, possibly through metaplasia of undifferentiated mesenchymal cells. It is also possible that they are derived from blood vessels that have invaded the AF as a result of disc degeneration. The finding of detection of progressive disc degeneration in both groups after 20-25 years seems to be of special interest because disc degeneration is a process that may not be directly correlated to disc herniation in these age groups.

Adolescent↗
PubMed1998

Augmentation of anterior transvertebral screws using threaded teflon anchoring.

This is a biomechanical study to investigate the effect of augmentation of single anterior transvertebral screws. Two subsequent experiments (pullout and caudal loading) were performed in 78 porcine vertebral bodies of equal bone mineral density using 6.5-mm transvertebral screws augmented or not with specially designed Teflon anchoring. Three different types of 35- and 45-mm unaugmented screws (Kaneda, TSRH, and Zielke) were inserted at 90 degrees laterally in the vertebral body and were tested for pullout force. The pullout load to loosen the three different unaugmented screws did not significantly differ. The pullout force to loosen the 35- and 45-mm Zielke screws was 507 +/- 22 and 860 +/- 50 N, respectively. The corresponding pullout load to loosen the construct Zielke screw-Teflon anchoring was 1,005 +/- 148 N and 1,306 +/- 135 N for the 35- and 45-mm screws, respectively. When comparing the pullout force needed for unaugmented versus the augmented Zielke screw of the same length, there was a statistically significant (p < 0.0001) difference. During the caudal loading test, the unaugmented 45-mm Zielke screw showed that a uniform slope up to the yield point occurred at 0.35 +/- 0.12 mm of displacement, with an average tilting force for the tested screw of 1,362 +/- 151 N, when the screw became loose. The caudal loading test for the augmented Zielke screw was interrupted at 2,000 N because the load applied exceeded the load capacity of the testing machine, and thus no loosening occurred. The findings of this in vitro study showed that the Teflon anchoring provides superior anchorage and stability of single transvertebral Zielke screws. However, further biomechanical and clinical studies are required before using this device or its modification.

Animals↗
PubMed1997

Use of the Texas Scottish Rite Hospital instrumentation in the treatment of thoracolumbar injuries.

STUDY DESIGN: This is a prospective study of the results of the use of Texas Scottish Rite Hospital instrumentation for thoracolumbar and lumbar injuries. To make an objective assessment of the clinical and radiologic results, the second and the third authors were used as unbiased assessors. OBJECTIVES: To evaluate the short-term results of the use of Texas Scottish Rite Hospital instrumentation in thoracolumbar injuries. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, there are only a few reports concerning the use of the Texas Scottish Rite Hospital instrumentation for stabilization of the spine, mostly in scoliosis and degenerative spine disease, and only one report on use of this instrumentation in thoracolumbar injuries. METHODS: Forty patients, with an average age of 45 years, who suffered from 48 thoracolumbar spinal fractures and dislocations, underwent posterior Texas Scottish Rite Hospital hook-rod instrumentation by means of "double-claw" configuration, two levels above and two below the lesion level for reduction of the injury, and stabilization and restoration of the sagittal profile of the thoracolumbar spine. Roentgenograms and computed tomography scans were evaluated on the basis of the same protocol before and after surgery and in follow-up observation. RESULTS: All patients were followed for an average period of 32 months. The sagittal profile of the thoracolumbar spine was restored significantly. No patient had neurologic deterioration after surgery, and all patients with incomplete lesions improved postoperatively at least one Frankel grade. One hook dislodgment was observed in one patient without loss of correction or non-union. There was only one deep infection. CONCLUSIONS: With the Texas Scottish Rite Hospital instrumentation, it was possible to provide solid internal fixation with restoration of the sagittal profile without loss of correction.

Female↗
PubMed1997

Three-level thoracic disc herniation: case report and review of the literature.

A rare case of three-level thoracic disc herniation with associated neurological impairment, including motor, sensor and urinary disturbances, is reported. The diagnosis and localization of the level of cord compression were mainly based on the clinical examination supported by the findings of magnetic resonance imaging and somatosensory evoked potentials. An anterolateral transthoracic approach at the upper-most affected level was selected for removal of all herniated discs, with the use of a surgical microscope; the resected rib was used for intervertebral fusion. An improvement in the patient's subjective and neurological condition was already apparent a few months after the operation, and solid fusion was roentgenographically found at all operated levels. The use of a surgical microscope allows complete removal of the herniated disc while avoiding wide vertebrectomy and associated iatrogenic damage to the spinal cord.

Adult↗
PubMed1997

Transthoracic disc excision with interbody fusion. 12 patients with symptomatic disc herniation followed for 2-8 years.

Thoracic disc herniation is a rare and slowly progressing disease, commonest at the lower thoracic spine. We performed transthoracic discectomy and interbody fusion in 12 patients with an average age of 46 years suffering from symptomatic herniated thoracic disc. Pain and neurologic impairment were the commonest symptoms at admission. The outcome at a mean follow-up of 4 (2-8) years concerning pain were excellent or good in 10 patients, fair in 1 and unchanged in 1 patient. There were no approach-related complications. All 7 patients with incomplete neurologic impairment preoperatively improved postoperatively at least 1 Frankel grade. Posterior complementary fusion at the thoracolumbar junction was necessary in 2 patients because of increasing symptomatic local kyphosis. Although the number of patients is small, due to the rarity of the disease, it seems that the transthoracic approach for anterior discectomy and fusion is an appropriate treatment for symptomatic thoracic disc herniation. Proper patient selection, preoperative planning and surgical technique resulted in good pain relief, neurologic recovery in cases associated with incomplete neurologic impairment and restoration of the sagittal profile of the thoracolumbar spine.

Adult↗
PubMed1996

Prediction of scoliotic cobb angle with the use of the scoliometer.

STUDY DESIGN: A prospective study was conducted in a young homogenous adolescent population, with the use of the scoliometer. OBJECTIVES: To create a mathematic formula that provides the accurate Cobb angle of idiopathic scoliosis with the use of the scoliometer only. SUMMARY OF BACKGROUND DATA: The scoliometer is an accepted method for detection and evaluation of scoliosis during screening programs. To the author's knowledge, there are no previous methods and formulas to estimate the approximate Cobb angle using only the scoliometer. METHODS: Several clinical (scoliometer value, age, and sex) and radiographic (Cobb angle, Perdriolle of and apical vertebra, Risser iliac apophysis classification) parameters from 442 (4.37%) of 10,109 screened adolescents who had a scoliometer value of at least 7 degrees were taken and correlated using the simple and multiple linear regression analysis. RESULTS: Cobb angle and scoliometer value were statistically significantly correlated to each other. Two mathematic formulas were created to predict the Cobb angle of the thoracic and lumbar scoliosis, with similar sensitivity and accuracy. The thoracic and lumbar scoliometer values were statistic significantly correlated with the thoracic and lumbar Cobb angle (P = 0.0254 and P = 0.0015, respectively). The lumbar scoliometer value was significantly correlated with lumbar apical vertebra Perdriolle value. Also, the thoracic and lumbar Cobb angles were significantly correlated with thoracic and lumbar apical vertebra (P = 0.0001 and P = 0.0015, respectively). CONCLUSIONS: In the present study, the authors have constructed two mathematic formulas, which provide accurately the scoliotic Cobb angle in young adolescents using only the scoliometer with a deviation of 5.63 degrees thoracic curves and 5.79 degrees for lumbar curves. The authors recommended that all physicians engaged in scoliosis screening programs use the scoliometer based on the mathematic formulas that the authors developed. They believe that this method will reduce the cost of school screening programs, the overdiagnosis, and the unnecessary exposure to irradiation of this young population in the future.

Adolescent↗
PubMed1996

Prevalence of scoliosis in beta-thalassemia.

The objective of this study was to determine the prevalence and possible pathogenesis of scoliosis in beta-thalassemia in our country, and to compare its characteristics to those of patients with idiopathic scoliosis from the same geographic area. Twenty-four [13 male and 11 female thalassemic patients aged 16 +/- 7 years (range 7-32 years)] of 115 examined patients with beta-thalassemia showed scoliosis of 14 degrees +/- 11 (range 10-65 degrees) radiologically. The prevalence of scoliosis in the thalassemic population was 21% in this series, whereas the overall prevalence of scoliosis in the general Greek population was 6% (Smyrnis PN, Valavanis J, Alexopoulos A, Siderakis G, Giannestras NJ: School screening for scoliosis in Athens, J Bone Joint Surg 61B:215-217, 1979). The scoliosis prevalence in the general population was significantly higher in the females (5%) than in the males (1%), whereas no difference in prevalence was found between the two sexes in the thalassemic population. The most common curve pattern in thalassemia was the left lumbar (38%) followed by the right lumbar (21%), whereas in patients with idiopathic scoliosis the left thoracolumbar most commonly appeared (25%) followed by the left lumbar (14%). No patient with thalassemia showed radiographic signs of congenital spinal deformities and spinal fractures, whereas all patients showed a significant retardation of their skeletal maturation. The age of the thalassemic patients with scoliosis was significantly (p = 0.0003) higher than in patients without scoliosis. The hematocrit of the thalassemic patients with scoliosis was significantly (p = 0.0012) lower than in those without scoliosis, whereas the rate of transfusions was not correlated with the magnitude of the scoliosis. The level of ferritin was significantly (p = 0.025) higher in the thalassemic patients with scoliosis than in those without scoliosis. The duration of Desferal treatment was significantly (p = 0.0357) longer in thalassemic patients with scoliosis when compared with those without scoliosis. Thus, the prevalence, curve pattern, and etiology of scoliosis in beta-thalassemia differ from those of idiopathic scoliosis, indicating that the spinal deformities in thalassemia represent a distinct type of scoliosis.

Adolescent↗
PubMed1996

Relapsing pancreatitis after combined anterior and posterior instrumentation for neuropathic scoliosis.

We report a case of pancreatitis in a 28-year-old woman who underwent a combined anterior Zielke procedure followed by Luque-TSRH (Texas Scottish Rite Hospital) operation in the same session for severe polioscoliosis. To our knowledge, only one case of a child with acute pancreatitis after posterior instrumentation for spondylolisthesis has been reported. In the early postoperative period, the patient developed acute pancreatitis that was diagnosed by a marked increase in plasma amylase and was confirmed by ultrasonography. The symptoms of pancreatitis in this patient temporarily resolved a few weeks after conservative treatment (diet, infusions, antibiotics). Six, 16, and 32 months after the combined operation, there were repeated relapsing episodes of pancreatitis with elevated amylase levels and concomitant symptoms. In the last follow-up evaluation in December 1995, the patient was well and the amylase levels were within normal limits. Although the etiology of pancreatitis in this case is obscure, we believe that the correction of the severe biplane spinal deformity, achieved by the two major operations on the spine in the same session, may have contributed to the pathogenesis of the disease. This observation suggests that pancreatitis after major scoliosis surgery should be suspected when abdominal symptoms persist associated with elevated serum amylase levels. Some cases of acute pancreatitis, such as this case, can persist in chronic-relapsing form for long periods postoperatively.

Abdominal Pain↗