Biomaterials as bone graft substitutes for spine surgery: from preclinical results to clinical study.

Vertebral fusion is performed in order to stabilize the spine in the presence of degenerative, traumatic or oncological pathologies that alter its stability. The autologous bone, harvested from the patient's iliac crest or from the lamina during surgery, is still considered the "gold standard" for spine fusion due to its osteogenic, osteoinductive and osteoconductive properties. However, several biological and synthetic bone substitutes have been introduced as alternatives for regenerating bone tissue. We have studied in particular the use of ceramic biomaterials prepared from hydroxypatite (HA), starting from in vitro analysis, through an in vivo study on ovine animal model and a post-market surveillance analysis, to finally design and perform a clinical study, which is ongoing in our Department. In the first step, HA-derived biomaterials were tested in vitro in the presence of bone marrow-derived human mesenchymal stem cells (hMSCs) and evaluated for their ability to activate precursor cells. In the second step, the biomimetic bone graft substitute SintLife® putty (MgHA) was evaluated in vivo. A posterolateral fusion procedure was applied on 18 sheep, where a fusion level was treated with MgHA, while the other level was treated with autologous bone. Microtomography and histological/histomorphometric analysis were performed six months of after surgery. In the third step, we reported the results of a post-market surveillance study conducted on 4 independent cohorts of patients (total 115 patients), in which HA-derived biomaterials were used as bone graft substitutes or extenders. Finally, a clinical study has been designed and approved by the Ethics Committee of our Institute and is currently ongoing. This study aims to evaluate the efficacy of the ceramic biomaterial SintLife® putty for bone replacement in patients treated by posterolateral fusion for degenerative spine disorders. HA biomaterials were effective in promoting the in vitro growth of hMSCs and their osteogenic differentiation. In the animal model, SintLife® putty has been effective in generating neo-formed bone tissue with morphological and structural features similar to those of the pre-existing bone. The post-market surveillance analysis has not reported any intra-operative nor early or late post-operative adverse events. Seven patients are currently recruited for the clinical trial designed to evaluate Sintlife efficacy for spine fusion (FU range: 1-7 months). No adverse events have been recorded. The first CT analysis performed at 6 months FU showed a good spine fusion. The study is ongoing. Our results, obtained from in vitro, preclinical and clinical studies, suggest that biomaterials derived from hydroxyapatite could be a valid alternative to autologous bone graft for vertebral fusion. This would potentially avoid or reduce the need of autologous bone harvesting and therefore, the risk of drawback-related side effects.

Effects of genetic factors to stent thrombosis due to clopidogrel resistance after coronary stent placement.

Stent thrombosis (ST) is considered as a multifactorial problem which is mostly occurs due to clopidogrel resistance. It may be due to some CYP450 enzyme deficiencies which play role in clopidogrel metabolism. Therefore the aim of this study is to detect the mutations in CYP2C19 and CYP2C9 genes which may cause ST, and to investigate the relation between other risk factors and ST. 50 individuals who have stent thrombosis and 50 individuals who haven't got any complication were enrolled as patient and control group respectively. *2,*3,*4,*5,*17 mutations in CYP2C19 gene and *2 ve *3 mutations in CYP2C9 gene were investigated with RT-PCR. Clopidogrel and aspirin resistance were investigated with multiple electrode platelet aggregometry. Results were evaluated statistically. CYP2C19*2 mutation was found statistically higher in patients (% 18), whereas CYP2C19*17 was found statistically higher in controls (% 36)(p<0.05). Additionally, it was found that patients who have clopidogrel and/or aspirin resistance also have CYP2C19*1/*2 or CYPC19*2/*2 genotype. These relations were also found statistically significant. (p=0,000005 for clopidogrel resistance and p=0,000059 for aspirin resistance). In conclusion, it was suggested that there is a relation between CYP2C19*2 mutations and ST due to clopidogrel resistance, and CYP2C19*17 may have a protective role in this process. The use of novel and more potent drug or high clopidogrel maintenance dosing before stent implantation may be beneficial treatment options for antiplatelet therapy in CYP2C19*2 carriers.

Medial olivocochlear reflex in ankylosing spondylitis patients.

OBJECTIVE: Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease. Via autoimmune mediators, AS can damage the auditory system similar to other systems. Otoacoustic emission studies in AS patients showed that the damage that causes hearing loss was in the outer hair cells. The medial olivocochlear (MOC) reflex is used to evaluate the MOC efferent system (MOES), which includes the outer hair cells. The aim of this study was to evaluate the presence of subclinical damage in the inner ear with the aid of the MOC reflex test in AS patients with no hearing complaints. PATIENTS AND METHODS: Thirty-four patients with AS and a control group of 30 healthy volunteers with similar demographic characteristics were evaluated in the study. Otoacoustic emission responses, MOC reflex results, and frequency-specific and total suppression findings were compared between the groups. The relationship between clinical and laboratory findings for the AS patients, and the MOC reflex data were also investigated. RESULTS: Reduced MOC reflex response (p = 0.04) and suppression (p = 0.019) were detected in AS patients. When the clinical and laboratory findings for the AS patients and the MOC reflex test results were compared, a significant correlation was found only between the MOC reflex and the erythrocyte sedimentation rate. CONCLUSION: The results showed that AS can damage the inner ear, especially the MOES, and can reduce the MOC reflex response without clinical hearing loss.

Is lumbar drainage of postoperative cerebrospinal fluid fistula after spine surgery effective?

AIM: This study is a retrospective consecutive case series analysis of 198 patients who underwent spine surgery between 2009 and 2010. The aim of this paper was to assess the efficacy and safeness of bed rest and lumbar drainage in treating postoperative CSF fistula. Postoperative cerebrospinal fluid (CSF) fistula is a well-known complication in spine surgery which lead to a significant change in length of hospitalization and possible postoperative complications. Management of CSF leaks has changed little over the past 20 years with no golden standard advocated from literature. METHODS: Postoperative CSF fistulas were described in 16 of 198 patients (8%) who underwent spine surgery between 2009 and 2010. The choice of the therapeutic strategy was based on the clinical condition of the patients, taking into account the possibility to maintain the prone position continuously and the risk of morbidity due to prolonged bed rest. Six patients were treated conservatively (position prone for three weeks), ten patients were treated by positioning an external CSF lumbar drainage for ten days. The mean follow-up period was ten months. RESULTS: All patients healed their wound properly and no adverse events were recorded. Patients treated conservatively were cured in a mean period of 30 days, while patients treated with CSF drainage were cured in a mean period of 10 days. CONCLUSION: Lumbar drainage seems to be effective and safe both in preventing CSF fistula in cases of large dural tears and debilitated/irradiated patients and in treating CSF leaks.

Spinal infection multidisciplinary management project (SIMP): from diagnosis to treatment guideline.

Spine infections require a multidisciplinary approach to be treated and solved. A guide line to drive physicians in the deep complexity of such a disease is extremely helpful. SIMP suggests a flow-chart built up on clear concepts such as right and well managed antibiotic therapy, sound stability of the spine, correct and smart use of the standard and functional imaging techniques, such as f18 FDG PET/CT. In 16 months a total of 41 patients have been treated for spondylodiscitis, discitis and vertebral osteomyelitis by our team of physicians and 25 patients have been enrolled in a prospective study whose target is the assessment of the SIMP flow-chart and of every single aspect that characterize it.

Osteoporotic vertebral fractures: a disabling and expensive disease of our century. A minimally invasive surgical technique to reduce the pain, the hospitalization, and restore the function.

BACKGROUND AND OBJECTIVES: Minimally invasive spine surgery has gained a great consent in the treatment of vertebral osteoporotic fractures. We perform a retrospective clinical and radiographic review on 32 consecutive patients (22 female and 10 male) surgically treated for a thoracolumbar osteoporotic fracture (type A) by a minimally invasive system. By this study, we propose to determine the safety and efficacy of an expandable, percutaneous, minimally invasive technique to reduce the disability caused by vertebral osteoporotic fractures. MATERIAL AND METHODS: We retrospectively reviewed 32 patients who were operated on between 2003 and 2004 by means of an innovative technique which employs an expandable system inserted by a minimally invasive approach into the vertebral body. Average age at surgery was 64.8 years (range, 27-82). All patients were mobilized in first post-operative day with no external immobilization and discharged from the Hospital in the second post-operative day. RESULTS AND CONCLUSIONS: This innovative technique which employs an expandable system inserted by a minimally-invasive approach into the vertebral body permits to obtain a double mechanical support for the vertebral plate, to partially reduce the fracture, to mobilize the patient immediately, reducing disability and costs related to the vertebral osteoporotic fractures.

Management of bone metastases.

Bone metastases are only apparently similar lesions, considering the large varieties of istotypes and the spread of the primary tumour. Although these metastases develop early and are not terminal events, they have to be considered as severe complications. When possible, surgical treatment can improve the history of the patient in terms of life expectancy and quality of life. The approach to these lesions should be multidisciplinary in collaboration with oncologists and radiotherapists. In fact the average of survival of these patients has increased in recent years. The evolution of anesthesiological techniques permits surgical treatments that once were considered prohibitive. The application of new adjuvant therapies increases the effectiveness for surgical treatment. Controversy exists over the most appropriate treatment for patients with bone metastatic disease. The purpose was to determine the best sequential process to arrive at the most appropriate treatment considering the individual general conditions and the parameters of the metastases. As the number of treatment options for metastatic bone disease has grown, it has become clear that effective implementation of these treatments can only be achieved by a multidisciplinary approach.

The impact of SARS-CoV-2 pandemic on Oncologic and Degenerative Spine Surgery Department activity: the experience of Rizzoli Orthopaedic Institute under COVID-19 lockdown.

OBJECTIVE: Experience of Department of Oncologic and Degenerative Spine Surgery of Rizzoli Orthopaedic Institute during SARS-CoV-2 pandemic lockdown. PATIENTS AND METHODS: Retrospective observational study of surgically treated patients from 09th March 2020 to 04th May 2020. DATA COLLECTED: age, sex, type of disease, neurological status, days of hospitalization, complications and type of discharge. A comparison analysis with same period of the last year was performed in order to evaluate the impact of COVID-19 spreading on daily surgical activity. RESULTS: A total of 107 surgical procedures in 102 patients were performed from 09th March 2020 to 04th May 2020. Analysis showed a statistically significant difference in age, sex, ASIA class and type of treated disease compared to the same period of the last year (p=0.042, 0.006, 0.022 and 0.007, respectively). No statistically significant differences were observed in type of discharge, length of hospitalization and complications (p= 0.447, 0.261 and 0.127, respectively). 3 COVID-19 infections have been identified in hospitalized patients. 1 COVID-19 patient wad admitted from Emergency Department and was managed according to a dedicated path. CONCLUSIONS: Surgical activity was paradoxically increased during SARS-CoV-2 pandemic lockdown through the management of urgent and non-deferrable spinal disease with a low rate (3,9%) of COVID-19 infections.

Spinal tuberculosis: proposed spinal infection multidisciplinary management project (SIMP) flow chart revision.

OBJECTIVE: We propose a revised flow chart of spinal infection multidisciplinary management project (SIMP) aimed to standardize the diagnostic process and management of spinal tuberculosis (TB). MATERIALS AND METHODS: We reviewed data from all TB cases with osteoarticular involvement treated at a large tertiary teaching hospital in Bologna, Northern Italy, from January 2013 to December 2017. We cross-linked notified osteoarticular TB cases with SIMP database and we analysed clinical, diagnostic, and treatment data of all cases managed by SIMP. RESULTS: Osteoarticular TB accounted for the 7.8% (n=40) of all TB cases notified between 2013 and 2017 (N=513). Among the identified cases, 52% (n=21/40) had spine involvement: all were enrolled and evaluated by SIMP multidisciplinary group. Females accounted for 57% (12/21) of patients, the median age was 52 years (range 24-82). In the 67% (n=14/21) of cases, the major clinical symptom of spinal TB was back pain reported for a median of 4.5 months (range 1-12 months) before hospital admission. The interferon gamma release assay was positive in 75% (n=16/21) of patients. All patients performed MRI with gadolinium, which indicated spondylodiscitis in 90%. 18F-FDG-PET/CT revealed average maximum standardized uptake value (SUV max) of 12.54 (range 5.3-22) in 17/19 (89.5%). Bacteriological confirmation of TB was obtained in 86% of cases (n=18/21). One-third of patients (7/21) underwent surgery and 95% successfully completed the anti-TB treatment. CONCLUSIONS: Our data reveal that a multidisciplinary approach to spine tuberculosis facilitates early and accurate diagnosis and can improve medical and surgical management of this disease.

Carbon ions therapy as single treatment in chordoma of the sacrum. Histologic and metabolic outcome studies.

OBJECTIVE: Even though carbon ions treatment (CIRT) of sacral chordoma (SC) substantially reduces tumor mass, tumor remnants are observed in most patients. Differentiating tumor remnants from necrosis is challenging, expensive in terms of imaging and time-consuming. So far, there has not been a systematic histological and metabolic analysis of post-CIRT lesions. We designed a prospective study aiming to histologically a metabolically differentiate between viable tumor and foci of necrosis and of fibrosclerosis after CIRT and correlate these findings to clinical outcome in patients with SC. PATIENTS AND METHODS: Between January 2013 and December 2016 18 patients, 12 males and 6 females, with histological confirmation of sacral chordoma, underwent CIRT. The total dose was 70.4 GyE, with a daily fraction of 4.4 GyE, for 4 weeks. MRI was performed every three months after treatment. FDG PET-CT scan and CT-guided needle biopsy were performed 6-12 months after CIRT. The incidence of complications (intraoperative and postoperative), local control (LC), overall survival (OS) and progression-free survival (PFS), changes in neurological status, clinical outcomes and toxicity were considered. RESULTS: All histological analysis but 2 reported signs of necrosis and of fibrosclerosis after CIRT. One of these 2 patients turned into a dedifferentiated chordoma. Radiological partial response (PR) was observed in 10 patients (56.3%) and stable disease (SD) in 5 patients (28.3). Two patients (11%) had a local relapse. The overall survival rate was 100% at 24 months. FDG PET CT after CIRT showed uptake decreasing compared with the baseline exam in all but one patient. CONCLUSIONS: The histological presence of necrosis and of fibrosclerosis after CIRT at the histological analysis supports the previous clinical evidence on the efficacy of CIRT. Volumetric stability of the residual mass should be considered as a success of treatment. In cases of a volumetric increase of the mass, a CT needle biopsy should always be performed. In our series, during the follow-up, the FDG-PET was able to promptly detect an increased uptake in the case which later was histologically defined as dedifferentiated chordoma.

Denosumab: non-surgical treatment option for selective arterial embolization resistant aneurysmal bone cyst of the spine and sacrum. Case report.

OBJECTIVE: Aneurysmal Bone Cyst (ABC) is a cystic lesion of bone, occurring in 70% of cases as a primary lesion. Even if the metaphyseal region of long bones is more frequently involved, vertebral localization is not rare: ABC represents 15% of all primary spine and sacral tumours. Selective arterial embolization (SAE) represents the first treatment option for vertebral ABC. However, in few cases, multiple SAEs are not possible. The aim of this work is to report two cases of vertebral ABC unresponsive to SAE positively treated with Denosumab. PATIENTS AND METHODS: Two patients affected by ABC of the lumbar spine were treated by SAE without any response. Thus, the patients were submitted to an off-label treatment with Denosumab, following the same protocol already used in case of Giant Cell Tumour (GCT): 120 mg once a week for 4 weeks consecutively, then once every 40 days. RESULTS: In both cases, patients resulted to be pain-free after 11-13 Denosumab administrations and CT scan showed almost complete ossification of the lesions. CONCLUSIONS: The two cases reported here are not conclusive but they may support the project of a prospective study to confirm the effectiveness of Denosumab in ABC treatment as an alternative to SAE.

Clinical features, diagnostic and therapeutic approaches to haematogenous vertebral osteomyelitis.

This article review the clinical features and the diagnostic approach to haematogenous vertebral osteomyelitis in order to optimise treatment strategies and follow-up assessment. Haematogenous spread is considered to be the most important route: the lumbar spine is the most common site of involvement for pyogenic infection and the thoracic spine for tuberculosis infection. The risk factors for developing haematogenous vertebral osteomyelitis are different among old people, adults and children: the literature reports that the incidence seems to be increasing in older patients. The source of infection in the elderly has been related to the use of intravenous access devices and the asymptomatic urinary infections. In young patients the increase has been correlated with the growing number of intravenous drug abusers, with endocarditis and with immigrants from areas where tuberculosis is still endemic. The onset of symptoms is typically insidious with neck or back pain often underestimated by the patient. Fever is present in 10-45% of patients. Spinal infections may cause severe neurological compromise in few cases, but mild neurological deficit, limited to one or two nerve roots, was detected in 28-35% of patients. The diagnosis of haematogenous vertebral osteomyelitis may be very difficult, as the symptoms can be sometimes not specific, vague or almost absent. The usual delay in diagnosis has been reported to be two to four months, despite the use of imaging techniques: in the early diagnosis of vertebral ostemyelitis is important the role of bone scintigraphy. The general principles for the management of spine infections are non operative, consisting of external immobilization and intravenous antibiotics, followed by oral antibiotics. Indications for surgery should be given in case of absence of clinical improvement after 2-3 weeks of intravenous antibiotics, persistent back pain and systemic effects of chronic infection and with presence or progression of neurological deficit in elderly or in cervical infection. Chronic ostemyelitis may require surgery in case of a development of biomechanical instability and/or a vertebral collapse with progressive deformity.

Carotid Doppler ultrasound evaluation in patients with pulsatile tinnitus.

A wide range of conditions, including atherosclerosis, may lead to pulsatile tinnitus. The objective of this study was to evaluate the patients with pulsatile tinnitus by means of carotid Doppler ultrasound parameters. Thirty-four patients with pulsatile tinnitus were enrolled in the study. Internal carotid artery intima-media thickness (IMT), blood flow velocities and arterial lumen diameters (LD) were measured and compared with the control group. Mean end diastolic velocity (EDV) (32.29 ± 17.22) and IMT (1.06 ± 0.36) values were significantly higher and mean LD (6.69 ± 1.20) was significantly lower compared to the control group. Peak systolic velocity and EDV values were significantly higher in patients whose IMT were greater than 1 mm. Pulsatile tinnitus may be the first symptom of a severe, life threatening disease. Doppler sonography is a noninvasive, safe and easily applicable diagnostic tool for the evaluation of the vascular structures, in patients with pulsatile tinnitus.

Endoscopic cartilage tympanoplasty in chronic otitis media.

OBJECTIVES: The use of endoscopic techniques is becoming more widespread in otological and neuro-otological surgery. One such procedure, endoscopic tympanoplasty, is used in chronic otitis media treatment. This study aimed to analyse the results of endoscopic transcanal cartilage tympanoplasty. METHODS: Data of tubotympanic chronic otitis media patients who underwent transcanal endoscopic type I cartilage tympanoplasty between June 2012 and May 2013 were analysed. The main outcome measures were graft success and hearing improvement. RESULTS: Graft success rates were 94.3 per cent and 92.5 per cent at post-operative months one and six, respectively. Post-operative air-bone gap values were significantly improved over pre-operative values (p < 0.01). CONCLUSION: Transcanal endoscopic type I cartilage tympanoplasty is a minimally invasive, effective and reliable surgical treatment option for chronic otitis media.

Diagnostic value of the wideband acoustic absorbance test in middle-ear effusion.

OBJECTIVES: This study aimed to investigate the diagnostic value of wideband acoustic absorbance testing in otitis media with effusion. METHODS: This prospective study compared middle-ear wideband acoustic absorbance rates in three paediatric patient groups: a healthy group of 34 volunteers; 48 patients diagnosed with otitis media with effusion; and 28 patients with chronic effusion but no sign of effusion during myringotomy. The diagnostic value of absorbance testing was analysed with the receiver operating characteristic test. RESULTS: The wideband acoustic absorbance rate was significantly lower in the otitis media with effusion group than in both the otitis media and healthy groups at the 0.375-2 kHz averaged mean absorbance (p < 0.017 and p < 0.001, respectively). Receiver operating characteristic analysis showed the highest diagnostic value for the 0.375-2 kHz averaged mean (area under the curve 0.984), followed by those at 1 and 1.5 kHz (area under the curve: 0.973 and 0.967, respectively). CONCLUSION: The wideband acoustic absorbance test is more accurate for detecting middle-ear effusion compared with conventional 226-Hz tympanometry. Its practicality and objectivity suggest that the wideband acoustic absorbance test may be a better alternative for diagnosing otitis media with effusion.

Improved artificial neural networks in prediction of malignancy of lesions in contrast-enhanced MR-mammography.

The aim of this study was to evaluate the capability of improved artificial neural networks (ANN) and additional novel training methods in distinguishing between benign and malignant breast lesions in contrast-enhanced magnetic resonance-mammography (MRM). A total of 604 histologically proven cases of contrast-enhanced lesions of the female breast at MRI were analyzed. Morphological, dynamic and clinical parameters were collected and stored in a database. The data set was divided into several groups using random or experimental methods [Training & Testing (T&T) algorithm] to train and test different ANNs. An additional novel computer program for input variable selection was applied. Sensitivity and specificity were calculated and compared with a statistical method and an expert radiologist. After optimization of the distribution of cases among the training and testing sets by the T & T algorithm and the reduction of input variables by the Input Selection procedure a highly sophisticated ANN achieved a sensitivity of 93.6% and a specificity of 91.9% in predicting malignancy of lesions within an independent prediction sample set. The best statistical method reached a sensitivity of 90.5% and a specificity of 68.9%. An expert radiologist performed better than the statistical method but worse than the ANN (sensitivity 92.1%, specificity 85.6%). Features extracted out of dynamic contrast-enhanced MRM and additional clinical data can be successfully analyzed by advanced ANNs. The quality of the resulting network strongly depends on the training methods, which are improved by the use of novel training tools. The best results of an improved ANN outperform expert radiologists.

Treatment of migraine with salmon calcitonin: effects on plasma beta-endorphin, ACTH and cortisol levels.

In this study we have examined the results of salmon calcitonin treatment on migraine pain. The mechanism by which calcitonin induces analgesia is still not understood. We observed the effect of a 5-day treatment with salmon calcitonin (IM 100 IU/day) on circulating levels of beta-endorphin, ACTH, and cortisol in 20 patients with migraine during the headache-free period. All 3 hormones were increased after the calcitonin administration and the maximum increase was obtained in beta-endorphin levels. There were significant statistical correlations between beta-endorphin, ACTH, and cortisol levels determined before and after calcitonin treatment.

Relationship between ACE gene polymorphism and ischemic chronic heart failure in Turkish population.

BACKGROUND: Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with the development of left ventricular hypertrophy, myocardial infarction, and remodeling. However, little is known about its role in ischemic chronic heart failure (CHF). We investigated the relationship between ACE gene I/D polymorphism and ischemic CHF and its influence on exercise capacity. METHODS: ACE gene I/D polymorphism was analyzed in 209 Turkish patients with coronary artery disease (CAD) undergoing coronary angiography. ACE genotype distributions were examined in 84 consecutive patients with ischemic CHF, functional capacity class II-IV to New York Heart Association and left ventricular ejection fraction (LVEF) < 40% and 125 consecutive patients with stable angina pectoris and LVEF > or = 40%. Furthermore the results of the cardiopulmonary exercise testing (CPX) in each ACE genotype were compared in medically treated ischemic CHF patients (n = 84). RESULTS: ACE genotype distributions were similar between the patients with and without symptomatic CHF in CAD. The odds ratios were 0.95 for D homozygotes (p > 0.05) and 0.98 for the D allele (p > 0.05). In patients with ischemic CHF the differences in CPX findings were statistically not significant in ACE D/D, I/D and I/I genotypes (peak oxygen consumptions 13.7 +/- 4.6; 14.6 +/- 5.1 and 14.5 +/- 5.0 ml/kg/min, respectively (p >0.05). CONCLUSIONS: In this study population, there was no evidence that ACE gene I/D polymorphism plays a role in the development of CHF in CAD or any influence on exercise capacity in treated patients with ischemic CHF.

Spinal metastases: treatment evaluation algorithm.

Spinal metastases are only apparently similar lesions, considering the large varieties of istotypes and the spread of the primary tumor. These metastases develop early and are not terminal events, they have to be considered as severe complications because, when possible, surgical treatment can improve the history of the patient in terms of life expectancy and quality of life. The approach to these lesions should be multidisciplinary in collaboration with oncologists and radiotherapists, in fact the average of survival of these patients has increased in recent years. The evolution of anesthaesiological techniques that permit surgical treatments that were once considered prohibitive. The application of new adjuvant therapy increases the effectiveness for surgical treatment. Controversy exist over the most appropriate treatment for patients with metastatic disease of the vertebral column. The purpose of this article was to determine the best sequential process to arrive at the most appropriate treatment considering the individual general conditions and the parameters of the metastases. We review 269 cases in 182 patients suffering from spinal metastases from a solid tumour treated between 1996 and 2002. As the number of treatment options for metastatic spinal disease has grown, it has become clear that effective implementation of these treatments can only be achieved by multidisciplinary approach.

The importance of statistics in documentation on hip prostheses.

The authors illustrate the possibilities and the limits of instruments that statistics currently make available in the analysis of a medical series involving hip prosthesis surgery. An analysis of the survival rate constitutes one of the most important tools with regard to data in the study of the effectiveness of implants, but its correct application is influenced by the assumption that so-called censored cases have no differences in survival in relation to those that remain under observation even in periods that follow. Simulation reveals the need to process series with a high number of cases, in order to obtain reliable estimates. Finally, only multivaried techniques allow for a correct evaluation of the incidence that single factors have in causing failure of implants.