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P Korovessis

Publications and source records attributed to P Korovessis.

At least 19 recordsLinked to original sources
PubMed2006

Metallosis after contemporary metal-on-metal total hip arthroplasty. Five to nine-year follow-up.

BACKGROUND: Authors of recent studies have reported early periprosthetic osteolysis in patients who have been treated with a contemporary metal-on-metal total hip arthroplasty and have suggested that metal hypersensitivity associated with an immunologic response to metal may be of etiologic importance. We evaluated the results and histologic findings in patients who had undergone revision of a failed contemporary metal-on-metal total hip arthroplasty. METHODS: Two hundred and seventeen total hip arthroplasties (SL-Plus stem and Bicon-Plus cup) with a Sikomet metal-on-metal articulation were implanted in 194 consecutive patients, and the results were retrospectively reviewed at a mean of seventy-seven months postoperatively. Clinical follow-up with the Harris hip score and plain radiographic evaluation were performed. Periprosthetic tissues from fourteen hips that had undergone revision arthroplasty were subjected to histologic analysis. RESULTS: The mean Harris hip score improved from 45 points preoperatively to 88 points at the final evaluation. Fourteen hips (6.5%) were revised: nine because of aseptic loosening, two because of technical failure, and three because of septic failure. Histologic examination of the retrieved periprosthetic tissues from the eleven patients who had undergone revision because of aseptic loosening or technical failure showed metallosis and extensive lymphocytic and plasma-cell infiltration around the metal debris. With removal of the component because of aseptic loosening as the end point, survivorship was 93% for the stem and 98% for the cup. CONCLUSIONS: Our findings are in agreement with those in recent publications and support the possibility that periprosthetic osteolysis and aseptic loosening in hips with a metal-on-metal articulation are possibly associated with hypersensitivity to metal debris. Prospective, comparative, randomized long-term studies are necessary to determine the cause(s) of loosening of prostheses with this particular articulation.

Adult↗
PubMed2001

Posterior compact Cotrel-Dubousset instrumentation for occipitocervical, cervical and cervicothoracic fusion.

The authors report on 32 consecutive patients with instability at the craniocervical, cervical and cervicothoracic regions suffering from various pathologies, who were treated with posterior instrumentation and fusion using the posterior hooks-rods-plate cervical compact Cotrel-Dubousset (CCD) instrumentation alone or, in three patients, in combination with anterior operation. The patients were observed postoperatively for an average of 31 months (range 25-44 months) and evaluated both clinically and radiographically using the following parameters: spine anatomy and reconstruction, sagittal profile, neurologic status, functional level, complications and status of arthrodesis. All patients but one (who died) achieved a solid arthrodesis based on plain and flexion/extension roentgenograms. Cervical lordosis (skull-C7) and cervicothoracic kyphosis (C7-T2) was improved by instrumentation towards a physiological lateral curve by an average of 33% (P<0.05) and 28% (P<0.05) respectively. Anterior vertebral olisthesis was reduced in the craniocervical and cervicothoracic region, by 73% and 90% respectively. At final follow-up there was an improvement of the neurologic Frankel status by an average of 1.2 grades and of myelopathy in 75% of the operated patients. Good to excellent functional results were seen in 77% of the operated patients, while acute and chronic pain was reduced by an average of 2.4 grades, on a scale of 0-3, in operated patients. No neurovascular or pulmonary complications arose from surgery. There was no significant change in lateral spine profile and olisthesis at the latest follow-up evaluation. There were no instrument-related failures. One patient requested hardware removal in the hope of reducing postoperative pain in the cervicothoracic region. The poor and fair results were related to the lack of improvement of neurologic impairment and myelopathy. The results of this study demonstrate that cervical CCD instrumentation applied in the region of the skull to the upper thoracic region for various disorders is a simple and safe instrumentation that restores lateral spine alignment, improves the potential for a solid fusion and offers sufficient functional results in the vast majority of the operated patients. However, the use of hooks in spinal stenosis is contraindicated.

Adult↗
PubMed2001

Prediction of thoracic kyphosis using the Debrunner kyphometer.

The Debrunner kyphometer is an accepted tool for detecting and evaluating thoracic kyphosis. This prospective study was conducted to create a mathematical formula that provides, with high approximation, the roentgenographic angle of thoracic kyphosis (T4-T12) using only the kyphometer. Several clinical (kyphometer value, age, and sex) and radiographic (Cobb angle [T4-T12]) parameters from 90 consecutively screened adolescents (44 male and 46 female) were correlated using simple and multiple linear regression analyses. The reliability of measurement using the Debrunner kyphometer was high. The kyphometer value was strongly correlated with the roentgenographically measured thoracic Cobb angle (simple linear regression analysis; probability range, 0.0026 to 0.0002). There was no correlation between age or sex and thoracic kyphosis. The predicted kyphosis angle using the kyphometer and the mathematic formula was 44.66 degrees +/- 2.68 degrees, (range 27 to 62 degrees), and the real roentgenographic kyphosis angle was 47.5 degrees +/- 3.53 degrees, (range, 24 to 70 degrees). The kyphometer and formula were more reliable and accurate when kyphosis less than 50 degrees was measured. In this study, the authors constructed a mathematical formula that accurately provides the roentgenographic T4-T12 kyphosis angle in adolescents using only the Debrunner kyphometer with a deviation of less than 3 degrees. The authors recommend that all physicians engaged in kyphosis screening programs use the kyphometer combined with the recently constructed simple mathematic formula. This method will reduce the cost of school screening programs, overdiagnoses, and unnecessary exposure of adolescents to irradiation.

Adolescent↗
PubMed2001

Effectiveness of transfixation and length of instrumentation on titanium and stainless steel transpedicular spine implants.

This study compares the effectiveness of transfixation on the stiffness of two pedicle screw-rod constructs of different manufacture, implant design, and alloy, applied in one-and two-level instability. Four screws composed of either stainless steel or Titanium were assembled in pairs to two polymethylmethacrylate blocks to resemble one-and two-level corpectomy models and the construct underwent nondestructive torsional, extension, and flexion loading. In every loading test, each construct was tested using stainless steel or titanium rods of 4.9-mm diameter in two different lengths (short, 10 cm; long, 15 cm), not augmented or augmented with different transfixation devices or a pair of devices. The authors compared the stiffness of stainless steel and titanium constructs without cross-link with the stiffness of that reinforced with single or double Texas Scottish Rite Hospital (TSRH) cross-link, closed new-type cross-link (closed NTC), or open new-type cross-link (open NTC). The results showed that augmentation or no augmentation of short rods conferred significantly more stiffness than that of long rods of the same material in all three loading modes. The closed NTC provided the greatest increase of torsional, extension, and flexion stiffness, and single TSRH provided the least amount of stiffness. Torsional stiffness of short stainless steel rods augmented or not augmented was significantly greater than that of their titanium counterparts. Torsional stiffness of long titanium rods was always greater than that of their stainless steel counterparts. Extension stiffness of short nonaugmented titanium rods was superior to that of long titanium rods, whereas extension stiffness of nonaugmented short and long stainless steel rods was similar. Nonaugmented short titanium rods showed greater flexion stiffness than that of long titanium rods. Long stainless steel rods displayed significantly greater flexion stiffness than did their titanium counterparts. This nondestructive study showed that cross-links increase the torsional stiffness significantly but less so the flexion and extension stiffness of both titanium and stainless steel posterior transpedicular constructs. This increase was proportional to the cross-sectional diameter of the cross-link. Titanium constructs showed more torsional stiffness when used in two-level instability and steel showed more torsional stiffness in one-level instability, particularly when they are reinforced. Stainless steel constructs showed greater flexion stiffness when they were used in two-level and titanium showed greater flexion stiffness in one-level instability, particularly when they were reinforced with stiff cross-links. The effect of transfixation on extension forces was obvious when thick cross-links were used.

Alloys↗
PubMed2001

The possible role of locally produced cytokines in the pathogenesis of peritrochanteric fractures in the elderly.

Sixteen patients with intertrochanteric femoral fractures were studied for possible involvement of the cytokines interleukin-6 (IL-6), interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha, and the disease activity factors C-reactive protein and alpha1-antitrypsin as local bone-resorbing agents. Cytokine and disease activity factor levels were measured in gluteus medius muscle and serum samples and were compared to sera obtained from age- and sex-matched healthy controls. Interleukin-6 and IL-1beta levels were significantly higher (P=.0024 and P=.036, respectively) in the muscle samples from the fractured side than in the samples from the contralateral unaffected side. Levels of IL-6 and IL-1beta also were significantly higher in patients' sera than in the sera of healthy controls. These results support a new hypothesis that may contribute to the pathogenesis of fractures in the elderly: unilaterally locally over-produced IL-6 and IL-1beta may lead to local bone resorption in the intertrochanteric region, which subsequently weakens the femoral bone and increases the risk of unilateral peritrochanteric fractures.

Aged↗
PubMed2000

Effects of thoracolumbosacral orthosis on spinal deformities, trunk asymmetry, and frontal lower rib cage in adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective study. OBJECTIVES: To document immediate and late changes in shape and balance of the thoracic and lumbar spine and lower rib cage on the frontal plane induced by treatment with a thoracolumbosacral orthosis (TLSO). SUMMARY OF BACKGROUND DATA: The effect of TLSO on lateral plane of spinal deformity, frontal lower rib cage, trunk balance, and natural history are poorly understood. METHODS: Twenty-four female adolescents with major thoracic and/or lumbar scoliosis, averaging 30 degrees and 26 degrees, respectively, were treated with a full-time TLSO program. Scoliosis, kyphosis, convex, and concave rib-vertebral angles T7 to T12, frontal trunk balance, frontal vertebral inclination, rotation and translation from T7 to L4-vertebrae were measured before bracing, 1 month after bracing, and biannually thereafter in brace and without brace for a 4-year period and reevaluated at the age of 20 years, at an average of 3.5 years after termination of bracing to measure any permanent changes. RESULTS: Thoracolumbosacral orthosis treatment corrected both thoracic and lumbar scoliosis and reduced lateral trunk shift at the expense of significant, although temporary reduced physiological thoracic kyphosis, increased lateral displacement of T7 to T10, increased frontal inclination of L2 to L4, and elevation of the apical concave rib in favor of reduction of lateral displacement of T11 to L4; decreased frontal inclination of T7, T9, and T11; and derotated L1 and L2 and thoracic apical vertebra without affecting drooping of the 7th to 12th ribs. In this series, there was marked inconsistency in the obtained changes in several of the roentgenographic parameters in the different evaluations, which is probably because of the empiric application of the TLSO during different periods of treatment. 3.5 years after termination of TLSO-wearing, all roentgenographic parameters remained to the prebrace values. CONCLUSIONS: Thoracolumbosacral orthosis program maintained the measured roentgenographic parameters at the prebrace levels in progressive adolescent idiopathic scoliosis, but it had no effect on the droop of the seven lower ribs. The TLSO treatment stopped progression of scoliosis and reduced the number of patients requiring surgery. Thus, it changed the natural history of scoliosis.

Adolescent↗
PubMed2000

Unilateral psoas abscess following posterior transpedicular stabilization of the lumbar spine.

A case of unilateral psoas abscess in a 58-year-old patient, shortly after posterior lower spine stabilization and fusion for spinal stenosis using transpedicular spine fixation is reported. The diagnosis was delayed because the patient's symptoms were referred to the thigh and the plain roentgenograms were negative for pathology. The technetium scintigram and computed tomography (CT) helped localization, diagnosis and treatment of the psoas abscess. Percutaneous CT-guided drainage was followed by recurrence of the abscess, and open surgical evacuation was performed successfully in combination with antibiotic treatment for 8 weeks. Psoas abscess should always be suspected when recurrent pain is associated with fever and elevated erythrocyte sedimentation rate after instrumentation of the lumbar spine. Hardware of a low profile and volume should be used to decrease dead space in the fusion area, and the volume of bone substitutes should be limited for the same reason.

Disease Progression↗
PubMed2000

Factor analysis of the effectiveness of transfixation and rod characteristics on the TSRH screw-rod instrumentation.

The effects of Texas Scottish Rite Hospital (TSRH) hardware parameters (rod length and diameter and cross-link) and their interaction on the stiffness of the TSRH pedicle screw-rod construct were evaluated. Four TSRH screws were assembled in pairs to two polymethyl-methacrylate blocks to resemble a one-level or more corpectomy model and the construct underwent nondestructive torsional, extension, and flexion loading. In every loading test, each construct was tested using TSRH rods of different lengths (10, 15, and 20 cm) and diameters (4.9 and 6.5 mm) and different cross-links (TSRH and two new types made for this experiment). We compared the stiffness of the construct without cross-linking with that with single or double TSRH cross-linking, or either the closed new-type cross-link (closed NTC) or the open new-type cross-link (open NTC) using factor analysis. There was no axial slipping of one rod versus the other up to a force of 100 kg. The stiffness of the construct in all three loading modes increased as the rod length decreased, the rod diameter increased, and the construct was augmented with a cross-link. The closed NTC provided the greatest stiffness and the single TSRH provided the least stiffness. Unaugmented 10-cm-long rods showed two or three times more torsional stiffness than did that of the longer unaugmented rods independent of rod diameter. In addition, the closed NTC offered the maximal increase in flexion stiffness of the construct with thick rods and 10-, 15-, and 20-cm-long rods at a maximum of 40%, 27%, and 30%, respectively. This rigid closed NTC increased the extension stiffness of the same construct with 10- and 15-cm-long rods at 40% and 6%, respectively, whereas it had no influence on the extension stiffness of 20-cm-long rods.

Biomechanical Phenomena↗
PubMed2000

Correlative analysis of the sagittal profile of the spine in patients with beta-thalassemia and in healthy persons.

This prospective study compares several roentgenographic parameters of the thoracic and lumbar spine in patients with beta-thalassemia and in healthy persons who served as controls. Eighty-four patients with beta-thalassemia and 84 age- and gender-matched healthy persons were examined clinically and radiologically (thoracic kyphosis, lumbar lordosis, and vertebral and sacral inclination). Although there was a significant difference in the vertebral inclination from T6 to L1, L4, and L5 between patients and controls, thoracic kyphosis and lumbar lordosis did not differ in the two groups. The apical vertebra of the thoracic kyphosis in patients and controls was T7 and T6, respectively, whereas L4 was the apical vertebra of the lumbar lordosis in both groups. There were no age- or gender-related differences in the magnitude of sacral inclination, thoracic kyphosis, or lumbar lordosis in the patients with beta-thalassemia compared with controls. Lumbar lordosis was significantly correlated with sacral inclination in both patients with beta-thalassemia and controls. Beta-thalassemia does not affect sagittal profile of the thoracic and lumbar spine but it is associated by structural changes on the frontal plane of the spine that are expressed as a high prevalence of scoliosis.

Adolescent↗
PubMed2000

Posterior stabilization of unstable sacroiliac injuries with the Texas Scottish Rite Hospital spinal instrumentation.

This article describes a new alternative technique for stabilization of unstable sacroiliac injuries using the Texas Scottish Rite Hospital (TSRH) instrumentation. The TSRH instrumentation was applied in 14 consecutive patients with unstable posterior pelvic ring disruptions. All patients underwent follow-up for an average of 29 months. Clinical results, using the rating system of d'Aubigne, were good in 9 and satisfactory in 5 patients. No pressure sores, infection, significant loss of correction, or hardware failures were observed postoperatively. The use of the TSRH instrumentation for stabilization of sacroiliac injuries offered sufficient stabilization of the posterior pelvic ring and permitted early mobilization without loss of correction.

Adult↗
PubMed2000

Medium- and long-term results of open reduction and internal fixation for unstable pelvic ring fractures.

Over a 10-year period, 74 patients with unstable pelvic injuries were treated with open reduction and internal fixation. Radiographic and clinical follow-up averaged 71 months (range: 38-141 months). Satisfactory (ie, good and very good) radiographic results were obtained in 90% of patients. Clinical results were superior in patients without associated injuries (P=.05-.001). Most of the complications in this series were due to associated injuries. Sepsis was mostly due to open pelvic injuries and malunion to either lack of patient cooperation or inadequate open reduction and internal fixation. Careful preoperative analysis of the nature of the pelvic injury and selection of the appropriate operative technique for open reduction and internal fixation result in a satisfactory outcome for the majority of operative patients.

Adolescent↗
PubMed1999

Medium- and long-term results of high tibial osteotomy for varus gonarthrosis in an agricultural population.

High tibial valgus osteotomy for varus gonarthrosis was performed in 63 consecutive patients in a homogenous agricultural population using two different surgical techniques. Patients were divided into two groups. A two-level Mittelmeier osteotomy was performed in group A patients, and a lateral closed wedge high tibial osteotomy using the AO/ASIF L-plate was performed in group B patients. Operations were performed by two different groups of surgeons. Patients were evaluated postoperatively for correction of knee axis, functional result, subjective impression, and complications. In group A patients, 80% of the operated knees were corrected to the mechanical axis and in group B patients, 82% of the knees were corrected to 6 degrees-10 degrees valgus of the anatomical axis. Ninety percent, 70%, and 54% of group A and 91%, 73%, and 57% of group B patients were rated as satisfactory results at 5, 9, and 12 years postoperatively, respectively; these differences were not statistically significant. One year postoperatively, 91% of group A and 96% of group B patients reported their symptoms had improved. However, patient satisfaction decreased at 5, 7, and 12 years postoperatively, with 91%, 89%, and 66% of group A and 96%, 93%, and 68%, respectively, of group B patients reporting their symptoms had improved; these differences were not statistically significant. Postoperatively, most patients returned to full agricultural activity. Total knee arthroplasty, which was later required in 12% of the knees, was not significantly jeopardized by the previous osteotomy.

Activities of Daily Living↗
PubMed1999

Clinical, radiographic, and scintigraphic comparison of the mechanical stability of Mueller and Zweymueller total hip prostheses.

Twenty-two cemented Mueller and 25 uncemented Zweymueller total hip arthroplasties (THAs) were performed in the same period in 47 consecutive randomly selected patients with unilateral primary osteoarthritis. Patients were evaluated using the same clinical and radiographic protocol preoperatively; 3, 6, and 12 months postoperatively; and annually thereafter as well as with Tc 99m MDP three-phase bone scintigraphy 3, 6, 12, and 24 months postoperatively. At 11 periprosthetic regions of interest (ROIs) around the stem and socket of each prosthesis, several radiographic parameters and bone scintigram uptake grade were recorded and correlated to determine the significance of early scintigraphic uptake for prediction of the stability of cemented and uncemented THA components over time. Around stable Zweymueller and Mueller sockets, the radionuclide uptake was similar during all periods of observation. Radionuclide uptake around stable Zweymueller stems was significantly more than around stable Mueller stems at the medial femoral cortex 3 and 6 months postoperatively, at the lateral femoral cortex 3-24 months postoperatively, and near the tip of the stem 3 months postoperatively. Radionuclide uptake around stable Mueller stems was significantly more than around Zweymueller stems at the greater trochanter 6 and 12 months postoperatively and at the lesser trochanter 12 months postoperatively. Any significant deviation of radionuclide uptake at any ROI, time, and THA component during the first 2 years postoperatively in combination with radiographic findings of loosening should be considered a serious predictive sign for loosening of a Mueller or Zweymueller THA component.

Aged↗
PubMed1999

Segmental roentgenographic analysis of vertebral inclination on sagittal plane in asymptomatic versus chronic low back pain patients.

Two homogenous groups of 120 volunteers and 120 low back pain (LBP) patients, age range 20-79 years, underwent a prospective roentgenographic segmental vertebral analysis of the thoracic and lumbar spine to compare several roentgenographic parameters useful for planning spine surgery. The following roentgenographic parameters were measured: thoracic kyphosis, lumbar lordosis, sacral inclination, distal lordosis (L4-S1), inclination of each vertebra from T4-S1, and relative vertebral inclination between adjacent vertebrae. Thoracic kyphosis increased (p < 0.0001) and sacral inclination decreased (p < 0.05) with age in the control group. Increased thoracic kyphosis correlated with decreased lumbar lordosis after the sixth decade in the control group (p < 0.01), less so in the LBP group (p < 0.05). Increased thoracic kyphosis was seen more in the LBP group than in the controls, but significantly solely in the sixth decade (p < 0.01). Lumbar lordosis was more increased in the controls than in the LBP group but significantly solely in the sixth decade (p < 0.001). The L5-S1 segmental lordosis was much more in the LBP patients than in the controls (p < 0.001). Lumbar lordosis was strongly correlated with sacral inclination in both groups (p < 0.0001) and it was significantly greater in the controls, particularly in the sixth decade (p < 0.001). Sacral inclination was significantly more in the female than in male volunteers (p < 0.05). Distal lordosis (L4-S1) represents 55% and 49% of total lumbar lordosis in controls and low back patients, respectively. Spine surgeons frequently deal with sagittal spinal deformities and the deviations of sagittal spinal curvatures and vertebral inclination in the sagittal plane, both in normal subjects and LBP patients should be clinically helpful.

Adult↗
PubMed1999

Mueller roof reinforcement rings. Medium-term results.

Short term results of cemented acetabular reconstruction with the use of the Mueller reinforcement ring in 30 hips in 29 patients have been reported previously. The indications for reinforcement were primary and postrevision segmental, cavitary, and combined acetabular deficiencies. The current study reports the medium term clinical and radiologic results of 20 of the 29 patients who were surgically treated (18 primary and eight postrevision hips) and who underwent followup with detailed clinical and radiographic analysis within an average of 9 years (range, 7-12 years). In the latest followup, there has been a statistically insignificant decrease in clinical scores compared with those obtained immediately after surgery; the changes probably are a result of the patients' aging. The radiologic scores at the latest followup were lower, although not statistically significant, than those at the short term followup. The causes of the three ring failures that occurred 5, 8, and 8.5 years after surgery and required revision arthroplasty were either acute trauma or tuberculous arthritis. Three additional hips (two primary and one revision) had evidence of loosening in the ring and socket associated with symptomatology and were considered as hips with impending revision. The rate of success of primary implantation was 94% at 7 years, 86% at 10 years, and 86% at 12 years and was not statistically different from that of revision implantation, which was 86% in all three followup periods. In this small series this surgical technique was successful and effective and followed by good medium term clinical and radiographic results in primary and revision implantation in segmental, cavitary, or complex acetabular deficiencies and in osteoporotic or deficient acetabular bone.

Acetabulum↗
PubMed1998

First experience with the use of compression cerclage Gundolf in orthopaedic and trauma surgery. A preliminary report.

In this prospective study we describe our experience with a new method of osteosynthesis of fissures, spiral and comminuted fractures of long bones of the extremities using the titanium compression cerclage of Gundolf (CCG). The operative technique is described in detail, and the results are presented for 50 operated patients who were followed up until fracture consolidation. The technique of application of the CCG is simple and quick and according to the results obtained ensures a permanent fixation at the site of the fracture. No cerclage-related complications such as stress shielding, corrosion, breakage of the band and impairment of the superficial cortical blood supply were radiologically observed in this series. We recommend the use of this titanium band in difficult cases of fractures of the long bones as well as in selected cases of primary and particularly revision hip arthroplasty.

Adult↗
PubMed1998

Monoradiculopathy of the fifth lumbar nerve root due to lumbar disc herniation between lumbar one and lumbar two vertebrae.

An extremely rare case is reported of a 34-year-old man who had a drop foot due to a herniated disc between the first and second lumbar vertebrae with a monoradiculopathy of the fifth lumbar nerve root. The diagnosis was made on the basis of myelography and magnetic resonance imaging (MRI), which revealed a disc centrolateral herniation at the level between the first and second lumbar vertebrae. The patient underwent anterior discectomy and fusion with the use of iliac bone graft. Because of increasing local kyphosis and associated symptoms, a posterior TSRH instrumentation was added successfully. Postoperatively the patient had alleviation of his symptoms, and at the 6-year follow-up evaluation, he was completely symptomless. The spine surgeon should be aware of the possibility of this rare location of lower lumbar nerve root compression within the dural sac. In such a case, myelography and MRI seemed to be superior to the computed tomography scan.

Adult↗