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Biomedical subjects

K N Malizos

Publications and source records attributed to K N Malizos.

At least 19 recordsLinked to original sources
PubMed2001

An MRI-based semiautomated volumetric quantification of hip osteonecrosis.

OBJECTIVE: To objectively and precisely define the spatial distribution of osteonecrosis and to investigate the influence of various factors including etiology. DESIGN: A volumetric method is presented to describe the size and spatial distribution of necrotic lesions of the femoral head, using MRI scans. The technique is based on the definition of an equivalent sphere model for the femoral head. PATIENTS: The gender, age, number of hips involved, disease duration, pain intensity, limping disability and etiology were correlated with the distribution of the pathologic bone. Seventy-nine patients with 122 hips affected by osteonecrosis were evaluated. RESULTS: The lesion size ranged from 7% to 73% of the sphere equivalent. The lateral octants presented considerable variability, ranging from wide lateral lesions extending beyond the lip of the acetabulum, to narrow medial lesions, leaving a lateral supporting pillar of intact bone. Patients with sickle cell disease and steroid administration presented the largest lesions. The extent of the posterior superior medial octant involvement correlated with the symptom intensity, a younger age and male gender. CONCLUSION: The methodology presented here has proven a reliable and straightforward imaging tool for precise assessment of necrotic lesions. It also enables us to target accurately the drilling and grafting procedures.

Adolescent↗
PubMed2001

Longstanding nonunions of scaphoid fractures with bone loss: successful reconstruction with vascularized bone grafts.

Vascularized bone graft from the dorsum of distal radius was used to treat 22 nonunions of scaphoid fractures, with a mean delay of 4 years from the initial injury. Four of the eight patients with associated scapho-styloid arthritis also underwent a closing wedge osteotomy of the distal radius. Follow-up time ranged from 14 to 74 months. Union was accomplished in 6 to 12 weeks and wrist range of motion and grip strength improved postoperatively in all patients. Complete absence of pain was noted in 16 patients and the other six, all of whom had arthritic wrist changes or carpal collapse, only experienced pain with strenuous activities. The simple graft dissection, the avoidance of anastomoses and the lack of donor site morbidity are additional advantages to this surgical technique, which is successful even in cases with an avascular proximal pole.

Adult↗
PubMed2001

Multimodal imaging quantitation of the lesion size in osteonecrosis of the femoral head.

Early diagnosis of osteonecrosis of the femoral head is important for initiating early treatment, which is associated with a more favorable outcome for patients. Confusion in evaluating the severity of the disease, and the clinical outcome after treatment partially is attributed to the use of various staging systems that are based on qualitative rather than quantitative criteria. At the authors' institution, 45 patients (77 hips) with osteonecrosis of the femoral head were evaluated using a multimodal imaging approach that included conventional radiography, bone scintigraphy, and magnetic resonance imaging. A computerized image analysis program that allowed quantification of the lesion size on radiographs and magnetic resonance images was used. Measurements of the extent of involvement on radiographs and selected serial magnetic resonance images were compared in 33 hips (42.9%) before collapse versus 44 hips (57.1%) after collapse. The size of the necrotic lesion varied significantly according to the specific stage of disease. Quantification of the lesion during the course of the disease provided a record of the progression of osteonecrosis, despite a spurious stability in staging. In general, conventional radiography closely approximated measurements of the lesion size obtained by magnetic resonance imaging. Bone scintigraphy and magnetic resonance imaging were well suited for detection of osteonecrosis at an early stage. Finally, precise quantification of the lesion size was an optimal preoperative means for evaluating the extent of involvement of the femoral head in the early and advanced stages of osteonecrosis.

Adolescent↗
PubMed2001

Reinnervation after end-to-side nerve coaptation in a rat model.

We assessed the effectiveness of end-to-side nerve coaptation by evaluating the extent of reinnervation and the integrity of the donor nerve in the rat. Fifty-six Sprague-Dawley rats were randomly divided into "fresh" and "predegenerated" (delayed) repair groups with or without a window in the perineurium. The right peroneal nerve was cut and sutured to the tibial nerve in an end-to-side fashion. Two and 3 months postoperatively, we measured the nerve conduction velocity (NCV) of the peroneal and tibial nerves, took dry muscle weights, and performed histologic studies. Peroneal NCV recovered up to 71% (2 mo) and 79% (3 mo), and tibial NCV recovered up to 88% (2 mo) and 91% (3 mo). The latter results indicate that this procedure had a slightly negative effect on donor tibial NCV. Dry weight of the tibialis anterior muscle returned to 60% (2 mo) and 82% (3 mo) of that of the contralateral side. Histologic results showed that there were numerous regenerating axons in the distal end of the peroneal nerve. Presence of a window in the perineurium improved the histologic profile significantly.

Animals↗
PubMed2001

Complications in limb-lengthening procedures: a review of 49 cases.

The purpose of this study was to examine the nature and number of complications relative to magnitude of limb lengthening. Results and complications of 50 limb-lengthening procedures were analyzed. There were 49 patients. Mean age was 21 years (range, 7-48 years). Lengthening was performed in 24 femora, 18 tibiae, 4 humerii, 3 radii, and 1 ulna. Average length gained was 5 cm (range, 3-15 cm) at average follow-up of 48 months (range, 12-76 months). Desired length was accomplished in all but 1 patient. The 69 complications varied in severity, but only 5 of these significantly impaired end results. The most serious complications occurred in patients with >30% bone lengthening. Patients with <15% lengthening had a significantly decreased complication rate. The healing index was lower in children. We conclude that incidence and severity of complications after limb-lengthening procedures are significantly influenced by relative lengthening of bone.

Adolescent↗
PubMed2000

Potential aetiological factors concerning the development of osteonecrosis of the femoral head.

BACKGROUND: The aetiology and pathogenesis of non-traumatic osteonecrosis (ON) of the femoral head have not been fully elucidated. The present study was conducted to evaluate the possible correlation of relevant haematological and biochemical factors with the development of ON. PATIENTS AND METHODS: Our investigation consisted of measurement of haematological indices and assessment of the biochemical and lipid profile of a study population of 68 patients with non-traumatic ON of the femoral head and 36 healthy controls. The disease was considered idiopathic in 17 and secondary in 51 patients. RESULTS: There were no statistically significant differences in the parameters measured among the idiopathic ON, secondary ON and control groups, except for globulins alpha1, alpha2 and beta, which were significantly increased in both patient groups, and apolipoprotein B (Apo B), which was increased in patients with idiopathic disease compared with the control group. Both patient groups presented increased von Willebrand factor (VWF) and lipoprotein (a) [Lp(a)] levels and decreased protein C and S concentrations, but without statistical significance. However, both patient groups exhibited a greater proportion of abnormal values of any of these parameters, in 58.9% of the idiopathic and in 62.7% of the secondary ON patients, compared with 8.3% of the controls. CONCLUSION: Our study underlines the potential association of abnormal values of protein C, protein S, VWF and Lp(a) with ON. To our knowledge this is the first reported association of VWF with the disease. The majority of both idiopathic and secondary ON patients in our series exhibits a thrombotic potential that adds further support to the postulation that intravascular coagulation is a major pathogenetic mechanism leading to the disease.

Adult↗
PubMed1999

Distal tibial epiphyseal fractures in adolescents.

The characteristic pattern of fusion of distal tibial epiphysis explains the special configuration of the fragments in the triplane fracture and the "juvenile" fracture of Tillaux in adolescents. The application of external rotation force produces Tillaux and triplane fractures of the lateral portion of the distal tibial epiphysis in patients with a mean age of 13.5 years. Eight patients, 13 to 15 years of age, with distal tibial epiphyseal fractures were treated in the last 12 years. Three of the fractures were classified as "juvenile" Tillaux fractures and five were triplane fractures. Open reduction and fixation of the tibia was accomplished by using either malleolar screws or K-wires. Follow-up time ranged from 1.5 to 11 years. All patients were evaluated subjectively and objectively after surgery. Objective evaluation included clinical assessment and radiographic evaluation. All patients regained full range of motion and no one complained of pain or joint stiffness. Radiographs confirmed that all fractures have healed without articular incongruity.

Adolescent↗
PubMed1998

Clinical criteria and treatment of segmental versus upper extremity reflex sympathetic dystrophy.

The effectiveness of a multimodal treatment protocol in the long-term management of upper extremity reflex sympathetic dystrophy (RSD), as well as of isolated finger involvement, was analyzed. In the present series, 62 patients diagnosed with RSD were treated and followed for a mean of 22.2 +/- 1.5 months. The findings in the present study indicate that: 1) RSD occurs predominantly in females (female:male, 3:1); 2) regional dystrophy is twice as common as segmental dystrophy; 3) segmental dystrophy is most often associated with minor traumatic dystrophy, whereas regional dystrophy is more evenly distributed among the various clinical types; 4) patients with regional dystrophy score their pain significantly higher; and 5) segmental and regional dystrophy respond with equal satisfaction to the multimodal treatment regimen. In conclusion, the weight of the available evidence strongly suggests that RSD is a complex multifaceted disease entity which responds well when managed with a multimodal treatment program aimed at the various interacting components of the disorder. Furthermore, the finding that segmental dystrophy did not behave differently from the treatment protocol compared to extensive upper extremity RSD, suggests that the anatomic location of the syndrome may not significantly alter the course of the disease during treatment.

Adolescent↗
PubMed1997

Knee dislocations and their management. A report of 16 cases.

We retrospectively studied the outcome of 16 knee dislocations. 11 patients had surgical treatment, 4 were managed nonoperatively and 1 patient died. In the elderly the outcome was poor, regardless of the type of treatment. Only 3 adolescents obtained excellent results and 2 young adults had good results after surgical repair of the knee. Concurrent arterial and nerve damage increased the morbidity.

Adolescent↗
PubMed1997

Blood salvage after total hip and total knee arthroplasty.

We performed a prospective study to determine the effect of postoperative collection and reinfusion of unwashed, filtered, salvaged blood alone and in combination with preoperative predeposited blood on the transfusion requirements of 375 patients treated with a total hip or total knee replacement. 208 patients were managed with postoperative blood salvage with use of the CBC ConstaVac autotransfusion system and closed suction drainage. Another 50 patients predeposited 1-4 units of autologous blood, before the operation, in addition to postoperative blood salvage. The remaining 117 patients were used as controls and were transfused with homologous blood from the blood bank. Postoperative reinfusion of salvaged blood decreased the need for homologous transfusion after hip and knee arthroplasty (mean 2.7 units) compared to controls (mean 4.2 units). The combination of postoperative reinfusion of salvaged blood and predeposited autologous blood was associated with the lowest requirements for homologous blood transfusions (mean 1.7 units).

Adult↗
PubMed1997

Neuromas and gaps of sensory nerves of the hand: management using vein conduits.

This study analyzed the efficacy of an interposed vein conduit graft in eliminating symptoms of painful neuroma of sensory nerves of the hand and preventing recurrence after excising the pathologic tissue and bridging the concomitant gap with the distal nerve segment. Twenty-three patients underwent reconstruction of 25 palmar sensory nerve gaps ranging from 12 mm to 28 mm, as well as 2 dorsal gaps of 32 mm and 35 mm, respectively. Eighteen patients had symptomatic painful neuromas. Subjective and objective evaluation criteria were employed for assessment and were compared with data obtained from primary direct suturing in 25 digital nerves of 21 patients. Electrophysiologic measurements, including sensory nerve action potential and conduction velocity, were similar, with both groups having values significantly lower than normal control values. Two-point discrimination measurements were slightly inferior for the vein conduit-reconstructed nerves compared with results attained after direct suturing. However, neuroma symptoms were eliminated, and in combination with the return of adequate sensibility, all but 1 patient resumed full hand function.

Action Potentials↗
PubMed1997

Reflex sympathetic dystrophy of the upper extremity. Clinical features and response to multimodal management.

The weight of available evidence suggests that reflex sympathetic dystrophy (RSD) is a complex clinical entity that (1) occurs predominantly in young adult women; (2) has five clinical types but presents most frequently as minor traumatic dystrophy; (3) has primary signs and symptoms (e.g., pain, edema, stiffness, and discoloration) that are expressed highly in each clinical type, whereas secondary signs and symptoms are variable; (4) responds well to treatment, regardless of its clinical type; and (5) is managed best when treatment is started early. It can be concluded that RSD is a multifaceted disease that responds well when managed with a multimodal treatment program aimed at the various interacting components of the disorder. The recognition and documentation of the variation of the clinical features of RSD may allow for its earlier diagnosis and treatment and thus significantly improve the chances for a successful outcome.

Analysis of Variance↗
PubMed1997

Two-stage treatment of flexor tendon ruptures. Silicon rod complications analyzed in 109 digits.

Complications during two-stage flexor tendon reconstruction may jeopardize the function of the repaired tendons. We reviewed complications encountered in 89 patients (109 digits) treated with a two-stage flexor tendon reconstruction using either silicone or Hunter rods. The complications could be distinguished according to the stage of reconstruction in which they occurred. Complications during stage I included rod buckling, rupture of the distal end of the rod, rod migration, synovitis and infection, and during stage II included distal rupture of the graft juncture, loose graft, tight graft, bowstringing, and flexion deformity of the PIP and DIP joints. The commonest complication was a flexion deformity of the PIP and/or DIP joint which was related to the surgical procedure. These deformities could easily be corrected in all cases with night splints.

Adult↗
PubMed1996

Major ablative procedures in orthopaedic surgery.

In the presence of the notable progress in limb-sparing techniques afforded by the developments in microsurgery and musculoskeletal oncology, major ablative surgery of the extremities still remains a last-resort, yet powerful tool in managing patients with primary tumors in whom wide excision is not possible, as well as in cases with severe trauma to the limbs. During the last thirteen years, eight major ablative procedures were performed at the Department of Orthopaedic Surgery of the University of Ioannina Medical School. Seven out of the eight procedures were performed in patients with primary malignant tumors either because the anatomical location or multiple recurrences of the tumor did not allow removal by wide local excision or by amputation at a lower level. In one patient, the procedure was related to a severe, mangling trauma. Four illustrative cases of the eight major ablative procedures performed are reported to highlight the current indications of this rarely used, complex, and extensive surgery. The characteristic cases presented are: hemipelvectomy in a patient with chondrosarcoma of the pelvis, disarticulation of the hip in a patient with a malignant histiocytoma of the supracondylar area of the knee, forequarter amputation in a patient with a basal cell carcinoma of the axilla, and disarticulation of the shoulder in a patient with an incomplete nonviable amputation at the level of the shoulder girdle associated with severe damage to the brachial plexus and axillary artery. After a five to over a ten year follow-up, six of the eight patients who where subjected to major ablative procedures are doing well and are satisfactorily active. These cases reflect the dilemma that orthopaedic surgeons geons still face in selecting limb salvage or major ablative surgery in cases of aggressive malignant tumors to severe trauma.

Amputation, Surgical↗
PubMed1996

Two-level dorsal dislocation of the little finger.

The case of an elderly man who suffered simultaneous interphalangeal joint dislocation in one finger as a result of a hyperextension force on both the distal and proximal interphalangeal joints is presented. This case differs from the few reports of this type of injury in the literature both in its mechanism of injury and time to reduction. Most reports have been in athletes who are actively involved in a sport, whereas the present case was the result of a fall. Also, successful reduction was achieved almost 2 weeks postinjury, indicating that, even with this amount of delay, these injuries can be effectively treated with closed reduction.

Accidental Falls↗
PubMed1995

Microsurgery in children.

Advances in microsurgical techniques have permitted replantation and reconstructive procedures to restore amputated or injured parts with a high degree of success in children. Despite this progress, some technical concerns remain. During a 15-year period, replantations were done in 53 children with major limb (18), hand (10), or digit (25) amputations. Even in patients with crush or avulsion injuries, the results suggest that replantation procedures are justified considering the superior recuperative ability in children. Free tissue transfer was used for reconstructive procedures in 26 children, including free flaps, vascularized bone transfers, nerve grafts, and toe-to-thumb transfers. The microsurgical success rate was 86.8% for replantation procedures and 96% for reconstructive procedures. Although the technical aspects and outcome of replantation attempts still differ between adults and children, there appears to be little difference in free tissue transfer. Thus, most replantation and reconstructive procedures can be attempted with a high possibility of success in children.

Amputation, Traumatic↗