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Biomedical subjects

M Stamatakis

Publications and source records attributed to M Stamatakis.

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↗
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

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

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

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↗
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↗
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

Course of bone mineral content changes around cementless Zweymueller total hip arthroplasty. A 4-year follow-up study.

In this prospective study we followed the bone mineral content (BMC) changes over time in seven zones of interest around uncemented Zweymueller total hip arthroplasty (THA) components, using dual-energy X-ray absorptiometry (DEXA) combined with a radiographical analysis of the distal femoral cortices, close to the tip of the stem. In 36 women (average age 55 years) operated on for primary hip osteoarthritis, BMC of the hips was measured preoperatively and 2 weeks, 1 year and 4 years postoperatively. In particular, a significant decrease of the preoperative values (ranging from 35% to 42.53%; P = 0.05 to 0.01) was noted immediately postoperatively in zones 2-7. Thereafter, an additional significant increase of BMC was observed between the first and last observations at the greater (30%, P < 0.05) and lesser (35.48%, P < 0.01) trochanter. The BMC changes over time were not related to the age of the patients. The BMC reduction observed immediately after implantation of the Zweymueller THA is probably related to the intraoperatively removed bone from (1) the medial and distal inner surface of the acetabulum and (2) the inner femoral cortex. Thereafter, the BMC in zones 2, 6 and 7 remained practically unchanged. The fact that a significantly delayed BMC increase was found in the region of the greater and minor trochanter 4 years later may be due to an increasing, continuous bone turnover in the intertrochanteric area. Thus, the Zweymueller screw socket becomes definitively anchored immediately postoperatively in the medial and distal thirds of the acetabulum and remains stable over time, whereas the Zweymueller stem is mainly anchored within the distal femoral cortex as well as within the mass of the greater and minor trochanter, and was still stable at the 4-year follow-up.

Absorptiometry, Photon↗
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

Changes in bone mineral density around a stable uncemented total hip arthroplasty.

Changes in bone mineral density (BMD) around the components of the Zweymueller total hip arthroplasty were measured, using dual energy X-ray absorptiometry, in 36 women who were operated on for primary osteoarthritis. Seven regions of interest were studied. No changes occurred around the screw socket and the greater trochanter: but there was a significant reduction of BMD, only when measured immediately after the operation at the lesser trochanter and at the distal femoral cortex lateral and medial to the tip of the stem. These changes were not related to the age of the patients. The reduction of BMD in the femur was mostly associated with areas where bone had been removed at operation. The press-fit fixation of the Zweymueller stem and the maintenance of its fixation with time did not induce further bone turnover around it. The absence of changes in bone mineral density was due to the relatively small amount of subchondral removed and to the continued stable fixation of the socket.

Absorptiometry, Photon↗
PubMed1996

Simultaneous three-level disc herniation in a patient with multiple sclerosis.

A rare case is presented of symptomatic simultaneous multilevel disc herniation in the cervical, thoracic and lumbar spine of a 38-year-old man, which were operated on at three different timepoints. Following the third operation, the patient was diagnosed with multiple sclerosis, based on pathological visual evoked potentials and cerebrospinal fluid examination. Spinal surgeons should be aware of the uncommon simultaneous presence of symptomatic disc herniations at different spinal levels, and of the possibility that such multilevel disc herniations may coexist with demyelinating diseases and may confuse the diagnosis.

Adult↗