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Biomedical subjects

Sandro Giannini

Publications and source records attributed to Sandro Giannini.

At least 19 recordsLinked to original sources
PubMed2007

Effects of freezing on the biomechanical and structural properties of human posterior tibial tendons.

This work analyzes the effects of storage by fresh-freezing at -80 degrees C on the histological, structural and biomechanical properties of the human posterior tibial tendon (PTT), used for ACL reconstruction. Twenty-two PTTs were harvested from eleven donors. For each donor one tendon was frozen at -80 degrees C and thawed in physiological solution at 37 degrees C, and the other was tested without freezing (control). Transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and biomechanical analysis were performed. We found the following mean changes in frozen-thawed tendons compared to controls: TEM showed an increase in the mean diameter of collagen fibrils and in fibril non-occupation mean ratio, while the mean number of fibrils decreased; DSC showed a decrease in mean denaturation temperature and denaturation enthalpy. Biomechanical analysis showed a decrease in ultimate load and ultimate stress, an increase in stiffness and a decrease in ultimate strain of tendons. In conclusion fresh-freezing brings about significant changes in the biomechanical and structural properties of the human PTT. A high variability exists in the biophysical properties of tendons among individuals and in the effects of storage on tendons. Therefore, when choosing an allograft tendon, particular care is needed to choose a biomechanically suitable graft.

Adult↗
PubMed2007

Alendronate improves screw fixation in osteoporotic bone.

BACKGROUND: Animal studies have demonstrated the efficacy of the use of bisphosphonates to enhance screw fixation in bone. In this prospective, randomized study of pertrochanteric fractures treated with external fixation, we tested whether systemic administration of bisphosphonates would improve the fixation of hydroxyapatite-coated screws implanted in osteoporotic bone. METHODS: Sixteen consecutive patients with a pertrochanteric fracture were selected. Inclusion criteria were female gender, an age of at least sixty-five years, and a bone mineral density T-score of less than -2.5 standard deviations. Exclusion criteria included bisphosphonate treatment during the two-year period prior to the fracture. Fractures were fixed with a pertrochanteric fixator and four hydroxyapatite-coated pins. Two pins were implanted in the femoral head (pin positions 1 and 2), and two were placed in the femoral diaphysis (pin positions 3 and 4). The patients were randomized either to therapy with alendronate for a three-month postoperative period (Group A) or to no therapy (Group B). The Group-A patients received an oral dose of 70 mg of alendronate per week. The fixators were removed after three months. RESULTS: All of the fractures healed, and no loss of reduction, nonunion, or delayed union was observed. The combined mean extraction torque (and standard deviation) of the pins implanted at positions 1 and 2 (cancellous bone) was 2558 +/- 1103 N/mm in Group A and 1171 +/- 480 N/mm in Group B (p < 0.0005). The combined mean extraction torque of the pins implanted at positions 3 and 4 (cortical bone) was 4327 +/- 1720 N/mm in Group A and 4075 +/- 1022 N/mm in Group B. CONCLUSIONS: These data show that weekly systemic administration of alendronate improves pin fixation in cancellous bone in elderly female patients with osteoporosis. We observed a twofold increase in extraction torque with the pins implanted in cancellous bone. These results support the use of alendronate in the treatment of osteoporotic pertrochanteric fractures to improve screw fixation in the femoral head.

Aged↗
PubMed2006

Surgical treatment of neck hyperextension in duchenne muscular dystrophy by posterior interspinous fusion.

STUDY DESIGN: Seven patients affected by Duchenne muscular dystrophy with neck hyperextension or poor head control in extension have undergone surgery consisting of posterior cervical interspinous fusion. OBJECTIVE: To report the results of surgical treatment of neck hyperextension executed simultaneously with the correction of the thoracolumbar scoliosis. SUMMARY OF BACKGROUND DATA: A severely progressive deformity of the spine in patients affected by DMD can involve also the cervical spine presenting a rigid neck hyperextension or poor head control in extension, forcing the patients to assume awkward compensating postures in order to look straight ahead, worsening significantly their quality of life. METHODS: The procedure consisted of a posterior approach to the cervical spine, correction of the hyperextension by releasing the fibrotic muscles and ligaments, and stabilization with bone grafts driven into the interspinous spaces, to achieve solid fusion. RESULTS: No surgical complications were observed, and fusion was achieved in all patients. The mean angle between C2-C7 decreased from an average of 29.8 degrees (7 degrees -56 degrees) before surgery, to an average of 18.5 degrees (6 degrees-30 degrees) at 1 year of follow-up. Range of motion between C1-C2 was preserved. CONCLUSIONS: Surgical treatment of neck hyperextension in these patients contributes to a better sitting position, to an easier nursing, to a better appearance.

Adolescent↗
PubMed2006

High prevalence of asymptomatic vertebral fractures in post-menopausal women receiving chronic glucocorticoid therapy: a cross-sectional outpatient study.

Glucocorticoid (GC)-induced osteoporosis mostly affects trabecular bone of vertebrae. Only 30% of vertebral fractures are symptomatic, yet both clinical and radiological vertebral fractures have been associated with increased mortality and morbidity. The aims of this cross-sectional, outpatient-based study were to measure the prevalence of asymptomatic vertebral fractures in a large sample of post-menopausal women given GCs for different diseases; to compare prevalence of asymptomatic vertebral fractures according to disease, GC treatment and major risk factors; and to assess the quality of life in GC users with and without asymptomatic vertebral fractures. 551 patients referring to 39 centers as outpatients for their programmed follow-up and satisfying the inclusion criteria were included in the analysis. Each patient underwent structured medical interview (including dose and duration of GC therapy, major risk factors for osteoporosis, the quality of life questionnaire of the European Foundation for Osteoporosis (QUALEFFO) and a back function score questionnaire), thoraco-lumbar radiographs and subsequent morphometry; for 253 and 437 patients, respectively, lumbar spine bone mineral density (BMD) assessed by dual energy X-ray absorptiometry and calcaneal bone stiffness assessed by quantitative ultrasonometry were available. The prevalence of asymptomatic vertebral fractures resulted >37%, with >14% of patients having two or more asymptomatic vertebral fractures and was much higher than that found in epidemiological studies on healthy women. Distribution of asymptomatic vertebral fractures along the spine showed a bimodal pattern, with two peaks at T7 and T11. The prevalence of asymptomatic vertebral fractures clearly increased with age. Differences in prevalence among diseases were evidenced. When controlled for age, GC cumulative dose, duration of therapy and personal history of fractures, the adjusted prevalences were 30.77% for systemic lupus erythematosus, 33.78% for rheumatoid arthritis, 37.78% for asthma/chronic obstructive pulmonary disease, 43.20% for polymyalgia rheumatica and 43.36% for diseases grouped as "other vasculitides/connective tissue diseases". No significant association was found with GC cumulative dose and duration of therapy. Established risk factors for osteoporosis (except for age, years since menopause and personal history of fractures), lumbar spine BMD, calcaneal stiffness and QUALEFFO score were not associated with number and severity of asymptomatic vertebral fractures. Underlying disease is likely to contribute to the risk of fracture, but disease by itself could not be dissected from GC regimen. Vertebral fractures should be looked for carefully in all post-menopausal women receiving long-term systemic GCs since they can be asymptomatic and are scarcely predictable.

Absorptiometry, Photon↗
PubMed2006

Clinical and biomechanical assessment of patella resurfacing in total knee arthroplasty.

BACKGROUND: Currently there is a limited understanding of the factors influencing range of motion by comparing patellar resurfacing vs non-resurfacing in total knee arthroplasty during activities of daily living. A recent meta-analysis of patellar replacement confirms better outcome with patella resurfacing; however, the result can be influenced by many other factors, such as: component design, surgeon experience, and technical aspects of the surgery. This study compares the biomechanics of the knee in patients after total knee arthroplasty with and without patellar resurfacing during stair climbing. METHODS: Forty-seven patients with total knee arthroplasty were assessed at the mean follow-up of 24 months. In all of them a posterior stabilised fixed bearing prosthesis (Optetrak PS, Exactech) was implanted. Twenty-six patients were treated without patellar resurfacing and 21 with patellar resurfacing. Clinical evaluations were performed using the International Knee Society and the Hospital for Special Surgery scores. Ten patients with patellar resurfacing and 10 patients without patellar resurfacing were also studied with motion analysis during stair climbing; 10 healthy subjects were studied for statistical comparison. FINDINGS: Clinical passive knee flexion, International Knee Society Function and Hospital for Special Surgery scores were significantly higher in the patellar resurfacing group. During stair climbing, active knee joint range of motion during the stance phase was greater in patients with patellar resurfacing. The maximum adduction moment was significantly higher in the group without patellar resurfacing. INTERPRETATION: Patients with patellar resurfacing demonstrated better clinical scores, and kinematic and kinetic data while ascending stairs.

Aged↗
PubMed2006

Minimally invasive radio-guided parathyroidectomy.

We reported here the data on minimally invasive radio-guided parathyroidectomy (MIRP) in a large group of 253 patients enrolled from the whole series of 355 consecutive patients affected by primary hyperparathyroidism (P-HPT) referred to our center. On the basis of preoperative imaging including Sestamibi scintigraphy and neck ultrasound (US), 263 patients (74% of the whole series) with evidence of a solitary parathyroid adenoma (PA) and a normal thyroid gland were addressed to MIRP and in 253 (96%) of them this minimally invasive neck exploration was successfully performed. The MIRP protocol developed in our center consisted of a very low 1 mCi Sestamibi injection in the operating room a few minutes before the start of intervention, thus minimizing the radiation exposure dose to the patient and personnel. No major intraoperative complication was recorded in patients treated by MIRP and only a transient hypocalcemia in 8.5% of cases. The mean duration time for MIRP was 35 min and the mean hospital stay 1.2 days. Local anesthesia was also performed in 62 patients, 54 of whom were elderly patients with concomitant invalidating diseases contraindicating general anesthesia. No HPT relapse was observed during subsequent follow-up. The gamma probe was used also during bilateral neck exploration in the group of 92 patients excluded from MIRP. The most frequent cause of exclusion from MIRP in our series was the presence of concomitant Sestamibi avid thyroid nodules (68.5% of cases) that can give false positive results at radio-guided surgery. In conclusion, MIRP is an effective treatment in patients with a high likelihood of a solitary PA and a normal thyroid gland at scintigraphy and US so that an accurate preoperative localizing imaging is required for MIRP. A low 1 mCi Sestamibi dose appears sufficient to perform MIRP. Patients with concomitant Sestamibi avid thyroid nodules should be excluded from MIRP.

Adenoma↗
PubMed2006

Femoral rollback of cruciate-retaining and posterior-stabilized total knee replacements: in vivo fluoroscopic analysis during activities of daily living.

Restoration of the physiological flexor/extensor mechanism at the knee in terms of appropriate muscular lever arms, proper required quadriceps force, and suitable patellofemoral compressive force, is fundamental for the success of total knee replacement. Therefore, measurements of anteroposterior translation of the femoral component over the tibial base-plate against joint flexion during daily living activities are essential for the assessment of the in vivo performance of current prosthesis designs. Patients treated with posterior stabilized and cruciate retaining prostheses with excellent clinical scores were evaluated during stair climbing, sitting and rising from a chair, and step up and down, using a three-dimensional pose reconstruction technique based on videofluoroscopy. The posterior stabilized patients experienced a fairly consistent and physiological rollback specific of each motor task, demonstrating proper function of the spine-cam mechanism. Rollback was somehow inconsistent among subjects in the cruciate retaining group, accompanied with a smaller range of knee flexion. In this group, more posterior locations of the condyles correlated significantly with higher clinical and functional scores. Articular surface conformity restores physiological rollback in the presence of a spine-cam mechanism, but not coherently in the presence of the posterior cruciate ligament.

Activities of Daily Living↗
PubMed2006

Scapulopexy of winged scapula secondary to facioscapulohumeral muscular dystrophy.

UNLABELLED: Facioscapulohumeral muscular dystrophy is an hereditary disease that causes weakness of the scapulothoracic muscles and leads to winged scapula. Patients with facioscapulohumeral muscular dystrophy are unable to sustain shoulder abduction or flexion and are limited in daily activities. We retrospectively reviewed nine patients (18 procedures) who had scapulothoracic fixation without arthrodesis (scapulopexy). The technique consists of repositioning the scapula over the rib cage and fixation to four ribs with metal wires. We assessed improvement in range of motion of the shoulder, maintenance of the correction with time, and cosmetic and functional results. The average age of the patients at surgery was 25.2 years (range, 15-35 years), and there were no major complications. The average followup was 9.9 years (range, 3-16 years). All patients had complete resolution of the winged scapula and improved range of motion. Arm abduction increased from an average of 68.3 degrees (range, 45 degrees-90 degrees) preoperatively to 96.1 degrees (range, 60 degrees-120 degrees) postoperatively. Arm flexion increased from an average of 57.2 degrees (range, 45 degrees-90 degrees) preoperatively to 116.1 degrees (range, 80 degrees-180 degrees) postoperatively. The position of the scapula obtained by surgery was maintained with time, and the patients had satisfactory cosmetic results. LEVEL OF EVIDENCE: Therapeutic study, Level IV. See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗
PubMed2005

Bisphosphonates decrease telomerase activity and hTERT expression in MCF-7 breast cancer cells.

Bisphosphonates are important in the management of tumours with secondary bone involvement. Recent findings have suggested that these drugs also have an effect on primary tumour burden. Telomerase is a cellular ribonucleoprotein reverse transcriptase responsible for elongation of the telomere. Telomerase expression is increased in many cancers. We studied the direct effects of clodronate, alendronate, and pamidronate (from 10(-6) to 10(-4) M) on MCF-7 human breast cancer cell line. In particular, we investigated their effect on viability, proliferation, apoptosis, human telomerase reverse transcriptase expression (h-TERT) by RT-PCR and telomerase activity. Alendronate and pamidronate showed an inhibition of viability (-63 and -35%, respectively; p < 0.0001) and proliferation of cancer cells, while no effect was observed with clodronate. Amino-bisphosphonates induced a significant increase of apoptosis in MCF-7. In addition, they showed a significant decrease in telomerase expression and activity with respect to control and to clodronate.

Alendronate↗
PubMed2005

Migration of cemented stem and restrictor after total hip arthroplasty: a radiostereometry study of 25 patients with Lubinus SP II stem.

The aim of this study was to investigate the migration pattern of the Lubinus SP II prosthesis stem. Migration at the stem-cement and at the bone-cement interface was assessed. Twenty-five patients were studied by radiostereometry during a period of 2 years. The migration of the head, of 2 points on the collar, of the stem tip, and also of the cement restrictor, was measured. The collar and the head were found stable at 2 years' follow-up, whereas an anterior migration occurred at the stem tip (median, 0.3 mm; 25th percentile, 0.04 mm; 75th percentile, 1.27 mm). Virtually no subsidence or axial rotation of the stems was observed. An anterior migration of the restrictor marker was also observed, compatible with a rigid sagittal plane rotation of the stem and of the cement mantle about the collar. Therefore, stem tip migration occurred at the bone-cement interface. Key words: total hip arthroplasty, anatomic stem, radiostereometry, subsidence, bone-cement interface.

Aged↗
PubMed2005

Secondary hyperparathyroidism is associated with vitamin D receptor polymorphism and bone density after renal transplantation.

Immunosuppresive treatment and secondary hyperparathyroidism (SHPT) are considered among the most important pathogenetic factors for post-renal transplant bone disease. The aim of this study was to investigate the relationships among vitamin D receptor (VDR) gene polymorphism, parathyroid hormone (PTH) levels and bone density in renal transplant recipients. We enrolled 75 patients (50 male and 25 female, mean age 47+/-11 years) who had undergone kidney transplantation 53+/-4 months before. All patients underwent an evaluation of the main biochemical parameters of bone metabolism as well bone densitometry. VDR alleles were typed by a PCR assay based on a polymorphic BsmI restriction site. When patients were categorized according to the VDR genotype (BB, Bb, bb), serum creatinine and the cumulative doses of immunosuppressive drugs were similar across the groups. PTH levels higher than 80 pg/ml were found in 53.6% of the patients, with the highest values being detected in the bb VDR genotype (P<0.05). PTH was significantly correlated to urinary NTx values. Bone density was low in the whole population; however, spinal bone density was lower in the bb subgroup (P<0.02). In the whole population, only PTH (P<0.05) and body mass index (P<0.01) were independent predictors of spinal bone density. Grouping patients by the VDR gene polymorphism, only PTH continued to be an independent predictor of spinal bone density in the bb allele subgroup (R(2) Adj.=0.17). We can conclude that the VDR genotype polymorphism affects bone density of renal transplant recipients via its effects on the severity of SHPT.

Adult↗
PubMed2005

Bone disease in primary hypercalciuria.

Primary hypercalciuria (PH) is very often accompanied by some degree of bone demineralization. The most frequent clinical condition in which this association has been observed is calcium nephrolithiasis. In patients affected by this disorder, bone density is very frequently low, and increased susceptibility to fragility fractures is reported. The very poor definition of this bone disease from a histomorphometric point of view is a crucial aspect. At present, the most common finding seems to be a low bone turnover condition. Many factors are involved in the complex relationships between bone loss and PH. Since bone loss was mainly reported in patients with fasting hypercalciuria, a primary alteration in bone metabolism was proposed as a cause of both hypercalciuria and bone demineralization. This hypothesis was strengthened by the observation that some bone resorbing-cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor nechrosis factor-alpha (TNF-alpha), are high in hypercalciuric patients. An excessive response to the acid load induced by dietary protein intake seems to be an additional factor explaining a primitive alteration of bone. The intestine plays a major role in the clinical course of bone disease in PH. Patients with absorptive hypercalciuria less frequently show bone disease, and a reduction in dietary calcium greatly increases the probability of bone loss in PH subjects. It has recently been reported that greater bone loss is associated with a larger increase in intestinal calcium absorption in PH patients. Considering the absence of parathyroid hormone (PTH) alterations, it was proposed that this is not a compensatory phenomenon, but probably the marker of disturbed cell calcium transport, involving both intestinal and bone tissues. While renal hypercalciuria is rather uncommon, the kidney still seems to play a role in the pathogenesis of bone loss in PH patients, possibly via the effect of mild-to-moderate urinary phosphate loss with secondary hypophosphatemia. In conclusion, bone loss is very common in PH patients. Even if most of the factors involved in this process have been identified, many aspects of this intriguing clinical condition remain to be elucidated.

Animals↗
PubMed2005

Surgical treatment of neck hyperextension in myopathies.

Neck hyperextension occurs in relation to several myopathies. It is a progressive increase of lordosis associated with a limitation in flexion of the cervical spine, forcing the patient to assume awkward compensatory postures to maintain balance and level vision. We evaluated operative complications, degree of correction, achievement of a solid arthrodesis, maintenance of the correction, and clinical assessment of seven patients. All had surgery in which the interspinous processes between C2-C7 were opened in a posterior approach and bone graft wedges driven into them to maintain the correction. The mean age of patients at the time of surgical intervention was 16.5 years (range, 10-28 years). The average followup was 10.4 years (range, 2.4-16.5 years). No major surgical complications occurred. After surgery, the average angle between C2-C7 in neutral position had decreased from 50.7 degrees (range, 40 degrees -70 degrees ) to 21.4 (range, 2 degrees -50 degrees ). The range of motion in the C1-C2 joint remained unaffected, whereas it decreased in C2-C7 from 33.5 degrees (range, 15 degrees -64 degrees ) to 1.8 degrees (range, 0 degrees -8 degrees ). A solid arthrodesis was achieved in all patients The followup showed significant clinical improvement of posture in all patients. The operating technique used proved to be safe and effective.

Adolescent↗
PubMed2005

Hydroxyapatite-coated external fixation pins.

The aim of this review is to report on studies of hydroxyapatite-coated external fixation pins as a solution to enhance pin fixation. In a highly loaded animal study, three tapered pin types were compared: Type A uncoated, Type B coated with hydroxyapatite and Type C coated with titanium. There was a 13-fold increase in the extraction torque of Type B pins compared with Type A, and a twofold increase compared with Type C pins. Extraction torque was significantly lower compared with the corresponding insertion torque in both Types A (p < 0.001) and C (p = 0.003). Conversely, with the hydroxyapatite-coated pins there was no difference between extraction and insertion torque. In a clinical study of 76 external fixation pins in 19 patients treated with hemicallotasis for osteoarthritis on the medial side of the knee, pin insertion and extraction torque forces were measured. The patients were randomized to be treated with either standard tapered pins or tapered pins coated with hydroxyapatite. Extraction torque of the hydroxyapatite-coated pins was higher than the extraction torque of the standard pins in both cancellous and cortical bone (p < 0.005). In a prospective, randomized clinical study of osteoporotic wrist fractures, extraction torque of the coated pins was higher than with standard pins (p < 0.0001). These studies demonstrate that with the use of hydroxyapatite-coated pins, no deterioration of pin fixation occurs, and that there is no significant pin loosening and infection, regardless of bone type and loading conditions.

Animals↗
PubMed2005

Dynamic hip screw compared with external fixation for treatment of osteoporotic pertrochanteric fractures. A prospective, randomized study.

BACKGROUND: Although the use of a sliding hip screw is considered to be the preferred treatment for pertrochanteric femoral fractures, we theorized that external fixation could produce clinical outcomes equal to, if not better than, the outcomes obtained with conventional treatment. Furthermore, because external fixation is minimally invasive, we expected a lower rate of morbidity and a reduced need for blood transfusions. Therefore, we compared the two treatments in a clinical trial of elderly patients with pertrochanteric fracture. METHODS: Forty consecutive elderly female patients who had a pertrochanteric fracture were randomized to be treated with either fixation with a 135 degrees four-hole sliding hip screw (Group A) or an external fixation device with hydroxyapatite-coated pins (Group B). The inclusion criteria were female gender, an age of at least sixty-five years, an AO/OTA type-A1 or A2 fracture, and a bone mineral density T-score of less than -2.5. There were no differences in patient age, fracture type, bone mineral density, comorbidities, length of hospital stay, or quality of reduction between the two groups. RESULTS: The average intraoperative time (and standard deviation) was 64 +/- 6 minutes in Group A and 34 +/- 5 minutes in Group B (p < 0.005). The average number of units of blood transfused postoperatively was 2.0 +/- 0.1 in Group A and none in Group B (p < 0.0001). Group B had less pain five days postoperatively (p < 0.05). Varus collapse of the fracture at six months averaged 6 degrees +/- 8 degrees in Group A and 2 degrees 1 degrees in Group B (p < 0.002). No pin-track infections occurred in Group B. The average Harris hip score at six months was 62 +/- 19 points in Group A and 63 +/- 17 points in Group B. CONCLUSIONS: This study showed that external fixation with hydroxyapatite-coated pins is an effective treatment for this fracture in this patient population. The operative time is brief, the blood loss is minimal, the fixation is adequate, and the reduction is maintained over time.

Aged↗