1,720,976 research outputs found
‘‘In situ’’ fusion or reduction in high-grade high dysplastic developmental spondylolisthesis (HDSS)
No full textPurpose To assess if the evaluation of the spino-pelvic
balance can be effective in the surgical decision making of
the high-grade high dysplastic developmental spondylolisthesis
(HDDS).
Methods Sixteen patients affected with high-grade HDDS
(6 treated with ‘‘in situ’’ fusion, and 10 with reduction and
fusion) were retrospectively evaluated. A clinical and
radiological assessment of the deformity correction was
carried out, with a minimum follow-up of 2 years. The
differences between the pre- and postoperative measures
were statistically analyzed using a two-tailed, paired t test.
Results The six patients treated with ‘‘in situ’’ fusion
showed no statistically significant change at the last followup
relative to pelvic tilt (PT), sacral slope (SS), and grade,
while the 10 patients treated with reduction showed significant
changes: PT significantly decreased following
surgery, while SS and grade significantly increased.
Conclusions The analysis of the spino-pelvic sagittal
balance allows to identify two types of HDDS: the balanced
deformities, which do not need reduction, and the
unbalanced deformities, in which correction is needed
Novel concepts in the evaluation and treatment of high-dysplastic spondylolisthesis
No full textThe classification system of spondylolisthesis proposed by Marchetti and Bartolozzi is the most practical regarding prognosis and treatment and includes the description of both low- and high-dysplastic developmental spondylolisthesis (HDDS). Unfortunately, it does not provide strict criteria on how to differentiate between these two subtypes. The accepted treatment for HDDS is surgical. However, there is no consensus on how to surgically stabilize this subtype of spondylolisthesis, and although the concept of reducing spinal deformity before fusion is attractive, the issue of surgical reduction versus in situ fusion remains controversial, especially for HDDS (Meyerding Grades III and IV). The purpose of this study was (1) to describe the severity index (SI) as a simple method that can be used in the identification of low-dysplastic developmental spondylolisthesis from HDDS allowing earlier surgical stabilization to prevent slip progression, (2) to provide guidelines for using the unstable zone for the inclusion of L4 in stabilization, and (3) to describe a surgical technique in the reduction and stabilization of this challenging surgical entity in an attempt to decrease the risk of iatrogenic L5 neurologic injury. The concepts of SI and unstable zone in the evaluation and treatment of HDDS are relatively new. In our study, patients with an SI value [20% were classified as having HDDS and surgical stabilization was offered. In addition, all vertebrae that were contained in the defined unstable zone were surgically instrumented and fused with attempts at anatomic reduction. This case series involved the retrospective radiological review of 25 consecutive patients surgically treated for HDDS between April 2000 and September 2004 by two senior surgeons. All 25 patients had a minimum 3-year follow-up. Reduction of slip, lumbosacral kyphosis, sacral inclination, fusion rate, maintenance of reduction, and iatrogenic L5 neurologic injury were evaluated. Twentytwo patients underwent a single-level L5–S1 fusion. Three patients had extension of the L5–S1 fusion to include L4 because it fell into the unstable zone. Slip improved from 67.2 to 13.6%, focal L5–S1 kyphosis improved from -17.5°to +6.4°. There were no pseudoarthroses and all patients had radiographic evidence of solid bony fusion at latest follow-up. To date, there have been no re-operations secondary to progression of deformity or loss of fixation. Two re-operations were performed, one for a superficial wound infection, the other for further laparoscopic decompression for continued L5 nerve root symptoms after the index surgery. One patient developed an iatrogenic L5 radiculopathy with dysaesthesiae 3 days postoperatively which completely resolved over 6 weeks. HDDS is best treated surgically. Early identification and stabilization of this challenging surgical entity could prevent the progression of slip and deformity making the index surgery less technically demanding. Vertebrae that are contained in the unstable zone can be instrumented and stabilized so that progression of the deformity and re-operation might be avoided. The authors suggested surgical technique can provide a way to restore sagittal balance, provide an environment for successful fusion, and decrease the risk of iatrogenic L5 neurologic injury
IS MINIMALLY INVASIVE SPINE SURGERY ALSO MINIMALLY PRO-INFLAMMATORY? MUSCULAR MARKERS, INFLAMMATORY PARAMETERS AND CYTOKINES TO QUANTIFY THE OPERATIVE INVASIVENESS ASSESSMENT IN SPINE FUSION
No full textOver the last decades, minimally invasive surgery (MIS) techniques entered in the surgical routine due to their major advantage in reducing the unnecessary exposure of tissue and, thus, the trauma. Even in the context of orthopedics and spine surgery these practices have been widely developed and applied. Besides the clinical outcome of the patients, few studies have quantitatively assessed the traumatic and inflammatory effects of a specific surgical technique. Indeed, currently, a universally accepted biological outcome measure, such as a panel of biochemical markers, to define the success of MIS approach is still lacking. We reviewed the literature to collect the published data regarding the quantitative analysis of trauma induced by either conventional or minimally invasive surgery with the aim of highlighting evidence useful to guide future studies. Previous publications show some evidence in support of the hypothesis that MIS approaches are less traumatic, and possibly less pro-inflammatory, than conventional ones. Creatin kinase (as a marker of muscular damage) and C-reactive protein (as a marker of systemic inflammation) seem to reproducibly follow different trends in minimally invasive surgery compared to conventional procedures. Moreover, cytoldnes, such as interleukin (IL)-6 and IL-10 are also promising markers in this context
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Mid-term evaluation of the effects of dynamic neutralization system on lumbar intervertebral discs using quantitative molecular MR imaging
No full textPurpose: To evaluate the mid-term effects of implant of
dynamic neutralization system (Dynesys) on disc tissue in
patients with lumbar discopathy, through the quantifica-
tion of glycosaminoglycans (GAG) concentration, both in
treated and adjacent levels, by analysis of delayed gado-
linium-enhanced MRI contrast (dGEMRIC) images.
Materials and Methods: Ten patients with low back pain,
underwent the dGEMRIC diagnostic protocol before, 6-
months and after 2 years from surgery. Each patient was
also evaluated with visual analog (VAS), Oswestry, and
Prolo scales both at presurgery and during follow-up.
From dGEMRIC images, a DT1 parametric map was
obtained for each disc, as quantitative indicator of its
GAG concentration, and divided in 13 sectors, which were
classified at presurgery as normal or abnormal, based on
a 70-ms threshold. Evolution of DT1 was studied during
the follow-up.
Results: Nine of ten patients completed the follow-up.
VAS, Oswestry, and Prolo grades showed an improve-
ment. This was accompanied by a reduction of DT1 in
abnormal segments while normal segments showed a pat-
tern of initial worsening at 6 months, followed by an
improvement after 2 years.
Conclusion: Our study confirmed the improvement in
clinical evaluation, and for the first time related this to
the changes in discs GAG concentration
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
