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Biomedical subjects

A Christodoulou

Publications and source records attributed to A Christodoulou.

At least 19 recordsLinked to original sources
PubMed2006

Neglected trans-scaphoid trans-styloid volar dislocation of the lunate. Late result following open reduction and K-wire fixation.

A rare case of radiocarpal dislocation is presented. The lunate and proximal pole of the scaphoid were displaced in a volar and proximal direction. The injury was missed initially and the patient was subsequently operated on six weeks later. Open reduction and internal fixation of the scaphoid was performed and this was followed by an uneventful postoperative period, with a satisfactory functional outcome at the eight-year follow-up, despite carpal instability non-dissociative-dorsal intercalated segmental instability configuration of the carpus. We believe that although open reduction in neglected cases carries the potential risks of avascular necrosis and nonunion of the affected carpal bones, an attempt should be made to restore the anatomy of the carpus.

Fracture Fixation, Internal↗
PubMed2006

The role of the dorsal vertebral cortex in the stability of transpedicular screws. A biomechanical study in human cadaveric vertebrae.

The aim of this biomechanical study was to investigate the role of the dorsal vertebral cortex in transpedicular screw fixation. Moss transpedicular screws were introduced into both pedicles of each vertebra in 25 human cadaver vertebrae. The dorsal vertebral cortex and subcortical bone corresponding to the entrance site of the screw were removed on one side and preserved on the other. Biomechanical testing showed that the mean peak pull-out strength for the inserted screws, following removal of the dorsal cortex, was 956.16 N. If the dorsal cortex was preserved, the mean peak pullout strength was 1295.64 N. The mean increase was 339.48 N (26.13%; p = 0.033). The bone mineral density correlated positively with peak pull-out strength. Preservation of the dorsal vertebral cortex at the site of insertion of the screw offers a significant increase in peak pull-out strength. This may result from engagement by the final screw threads in the denser bone of the dorsal cortex and the underlying subcortical area. Every effort should be made to preserve the dorsal vertebral cortex during insertion of transpedicular screws.

Adolescent↗
PubMed2006

Does aprotinin reduce blood loss in total hip arthroplasty?

This prospective randomized study examined the effects of aprotinin during total hip arthroplasty (THA). Fifty patients who were enrolled in the study received aprotinin or normal saline. Mean intraoperative blood loss was reduced from 1496 mL in the control group to 1073 mL in the aprotinin group. The mean transfusion unit was 1.56 in the aprotinin group and 3.8 in the control group.

Adult↗
PubMed2005

Fracture callus engulfing a peripheral nerve does not affect its function: an experimental study in rabbits.

The fate of a peripheral nerve engulfed in fracture callus is not known. We investigated the impact of envelopment of the sciatic nerve by fracture callus using a New Zealand rabbit femoral fracture model. The sciatic nerve was mobilized and coiled around the ipsilateral femur, which was surgically fractured, shortened, and osteosynthesized. Bony union was achieved, and callus engulfed the sciatic nerve in all animals. Nerve function was evaluated clinically and by conduction studies preoperatively and postoperatively. Although the nerve function in terms of clinical evaluation, amplitude, motor latency, and spontaneous activity deteriorated immediately postoperatively, recovery was evident in the following weeks indicating that the detected nerve dysfunction was attributable to the surgical mobilization. In addition, histologic and quantitative histomorphometric analyses proved that in none of the animals did the callus compress the sciatic nerve whereas an impressive process of axonal regeneration took place despite callus maturation. Results of our study suggest that callus, engulfing a peripheral nerve, does not compress it and the nerve appears to be intact in an osseous canal. This results in preservation of the integrity and function of the nerve, which may have significant clinical applications.

Analysis of Variance↗
PubMed2004

Supracondylar femoral fractures in elderly patients treated with the dynamic condylar screw and the retrograde intramedullary nail: a comparative study of the two methods.

INTRODUCTION: The objective of this study is to present the results of surgical management of supracondylar fractures of the femur (types A and C according to the AO/ASIF classification) in elderly patients with the use of two different methods of fixation: the mini open dynamic condylar screw fixation (DCS) and the closed retrograde intramedullary nailing (RIN). MATERIALS AND METHODS: Eighty patients with supracondylar fractures of the femur were treated from January 1994 to June 2000 and 72 of them followed up completely. There were 25 (34%) men and 47 (65%) women with a median age of 73.2 years (range 60-88 years). In patients with the same type of fracture, the chosen method was random, one after the other (alternately). RIN was used in 35 patients, and DCS was used in 37. The mean operative time for the DCS fixation group was 145 min (range 115-180 min), whereas for the RIN group it was 92 min (range 76-110 min) (p<0.001) with an average estimated blood loss of 310 cc (range 120-450 cc) and 118 cc (range 90-165 cc), respectively (p<0.001). The mean follow-up was 28 months (range 18-42 months). RESULTS: According to the criteria set by Schatzker and Lambert, excellent results were recorded in 18 (51%), good in 11 (31%), moderate in 3 (9%), poor in 3 (9%) patients with RIN and excellent in 19 (51%), good in 11 (30%), moderate in 4 (11%) and poor in 3 (8%) patients with DCS (p>0.05). The complications that occurred in the RIN group were 2 (6%) stiffness of the knee (mean flexion 80 degrees), 2 (6%) non-unions, 2 (6%) varus deformity and in the DCS group 2 (5%) haematomas, 4 (11%) stiffness of the knee (mean flexion 73 degrees) and 2 (5%) non-unions. CONCLUSION: Although the two methods appear to have the same percentage of excellent results and same time to bony union, RIN is preferable to DCS in terms of less blood loss and shorter operating time.

Age Factors↗
PubMed2004

Soleus accessorius, an anomalous muscle in a young athlete: case report and analysis of the literature.

The soleus accessory muscle is a rare anatomical variation. It usually appears as a soft tissue mass and may be mistaken for a tumour or an inflammatory lesion. The differential diagnoses include ganglion, lipoma, haemangioma, synovioma, and sarcoma. This is a report of such a muscle mass in the leg of a young athlete with 16 years follow up. A review of the English literature on this subject is also presented.

Adolescent↗
PubMed2003

Sizable pseudoaneurysm of the abdominal aorta after laparoscopic cholecystectomy: a report of a serious complication.

After the first successful laparoscopic cholecystectomy in Europe by Phillipe Mouret, the method quickly became established all over the world. In the meantime, its advantages and complications have been identified. In rare cases, major vascular injuries occur as serious and deadly complications of laparoscopic surgery. We present the case of a patient with a sizable pseudoaneurysm of the abdominal aorta that was identified 5 months after the performance of a laparoscopic cholecystectomy at another hospital. Thereafter, we review the literature in search of some methods that can be used to avoid vascular injuries.

Aged↗
PubMed2002

Free-electron-laser oscillator with a linear taper.

We present experiments and simulations showing the behavior of a free-electron laser (FEL) with both positive and negative linear tapers along the wiggler. We show the power desynchronism curve widths, efficiency, exhaust electron energy spread, and wavelength dependence as a function of taper for 3- and 6-microm optical wavelengths and for resonators with 10% and 2% loss/pass. Simulations of the experiments, using a multimode analysis, are seen to be in general agreement with the experimental results, carried out at the IR Demo FEL at Thomas Jefferson National Accelerator Facility. We find that short-pulse effects are more effective than tapers in producing high efficiency with low exhaust energy spread, and the expected performance enhancement of FEL tapering is not achieved.

Journal Article↗
PubMed2002

Morphometric characteristics of the thoracic and lumbar pedicles in the Greek population.

OBJECTIVES: To measure the dimensions of the pedicles of T1 to L5 in the Greek population. METHODS: A total of 12 whole human cadaver spines were evaluated regarding pedicle dimensions (5 women and 7 men). The mean age at the time of death was 69,6 (range 62 to 84 years). The transverse and sagittal out side pedicle isthmus widths, the internal transverse diameter and cortex width were measured with electronic calipers both on the right and left pedicles. The data collected were statistically analyzed with the t-test. RESULTS: The widest transverse diameter was at the L5 level with a mean of 11,3mm (range 7,55-15,46mm). The narrowest transverse diameter was at the T5 level with a mean of 5,37mm (range 4,10-6,88mm). The widest sagittal diameter was at the T11 level with a mean of 17,23mm (range 14,84-19,57mm), while the narrowest one was at T1 level with a mean of 9,1mm (range 7,18-11,37mm). The maximum internal transverse diameter was at the L4 level with a mean of 8,26 mm (range 7,10-9,23mm) while the minimum was at the T5 level with a mean of 3,9mm (range 3,14-4,78mm). The maximum cortex width was at the L5 level with a mean of 2,55mm (range 2,15-3,02mm) and the minimum at the T5 level with a mean of 1,30mm (range 0,40-2,10mm). CONCLUSIONS: From the statistic analysis of the above data it was found that regarding the internal diameter there was statistically significant difference between males and females especially at T3, T7, T8 and L3 levels (P<0,05), and almost in all levels regarding the cortex width. There was also statistically significant difference between right and left pedicles regarding the transverse and the sagittal widths (P<0,05). The narrowest pedicle was at the T5 level and the widest was at the L5.

Aged↗
PubMed2002

Idiopathic scoliosis. Segmental fusion with transpedicular screws.

The purpose of this study is to evaluate whether the surgical correction of the scoliotic curve with the use of segmental pedicle screw fixation system is effective. We studied 20 patients (19 girls, 1 boy) with a mean age of 14,6 years (range from 13 to 22). The spinal deformities were evaluated by Cobb method with anteroposterior and lateral bending radiographs. There were 13 right thoracic curves and 7 left thoracolumbar curves. The width of the pedicles was estimated in all patients by computerized tomography of the thoracic and lumbar spine. Posterior instrumentation (Moss-Miami transpedicular system) was used and additional thoracoplasty was performed in 2 patients. The transpedicular screws were placed between T2 and L5. Intraoperatively the image intensification was indispensable and the wake-up test was always conducted. All the patients were assessed both clinically and radiographically at 3,6,9,12 months and annually until now. The average follow-up was two years. There was an average correction of 73% of the primary curve (pre-op standing average 59 degrees (range from 42 degrees to 87 degrees), lateral bending average 33 degrees (range from 10 degrees to 75 degrees), post-op average 13 degrees (range from 6 to 30 degrees), at last examination average 14 degrees (range from 6 degrees to 33 degrees). Infection and neurological complications were not noted. No major complications were observed. Exact evaluation of the pedicles by CT scan is an essential prerequisite for transpedicular screw insertion. The correction of idiopathic curves with the use of segmental pedicle screw fixation system is a very effective method(correction > 70%) It seems that control of the three columns of the spine by the transpedicular screws offers sufficient apical translation and coronal realignment.

Adolescent↗
PubMed2002

Surgical management of a congenital kyphotic deformity in an adolescent.

This is a case of an adolescent with kyphoscoliosis due to congenital partially segmented vertebrae T12, L1, L2 who was treated operatively by a back-front-back, one stage operation. A 16 year old patient neurologically intact with a rounded gibbous in the lower thoracic region and a mild scoliotic element had no other congenital anomaly. His kyphotic deformity was 85 degrees measured with the Cobb method. Preoperatively, a CT and MRI scan of the spine was performed and a three-level anterolateral failure of segmentation in the thoracic spine was diagnosed without spinal dysraphism. The operation lasted 8 hours and the Moss-Miami anterior and posterior fixation systems were used for fusion from T10 to T4. It included initially posterior approach for transpendicular screw insertion, wedge resection of the posterior elemens followed by anterior approach (thoracotomy), osteotomy of the defected vertebrae, anterior correction and fusion T11 to L1 and final correction with rod placement posteriorly. The wake-up test was performed twice. The follow-up was 3 years. The postoperative correction of the kyphosis was 45% (42 degrees) and there was practically no loss of correction in the last follow-up. No complications were observed. Detailed preoperative assessment of the patients with congenital deformities is essential in order to establish the correct diagnosis and choose the proper treatment. Substantial kyphotic deformities require combined antero-posterior procedures.

Adolescent↗
PubMed1997

Replacement of deficient acetabulum using Burch-Schneider cages. 22 patients followed for 2-10 years.

The absence of good bone stock with massive acetabular deficiency has been a major problem in both revision hip arthroplasty and in primary arthroplasty for congenital dislocation of the hip (CDH). 22 patients (24 hips; 21 revision and 3 primary replacements: mean age 58 years) with substantial bone loss underwent acetabular reinforcement with Burch-Schneider cages. Classification of acetabular deficiency was made according to the AAOS system. The surgical procedure involved preparation of acetabulum, filling the defect with bone autografts, placement of the cage with its flanges, fixation with screws on the lateral wall only and placement of a cement and plastic cup. Radiographic loosening with breakage of the screws was observed in only 1 patient. After a mean follow-up of 8 (2-10) years, good stability was achieved in all patients and no mechanical failure was observed. Satisfactory results were observed in all but one of the cases, indicating that effective support of the acetabulum can be achieved using Burch-Schneider cages.

Acetabulum↗
PubMed1991

Effect on atrial natriuretic peptide by bracing in scoliosis. Boston brace removal studied in 10 cases.

The immediate effect of Boston brace removal on plasma levels of atrial natriuretic peptide and arginine vasopressin was studied in 10 patients with idiopathic scoliosis ranging in age from 12 to 16 years. Blood samples were drawn via the antecubital vein in the supine position with the brace on and 10 min after brace removal. ANP and AVP plasma levels were measured by radioimmunoassay. Although no differences were found in the plasma concentrations of arginine vasopressin while on and after removal of the brace, atrial natriuretic peptide levels showed an approximately 80 percent increase 10 min after brace removal, presumably due to central volume redistribution. The changes of atrial natriuretic peptide plasma levels observed may be related to previously reported changes of the glomerular filtration rate and urinary sodium excretion following brace removal.

Adolescent↗