Nucleus disc arthroplasty with the NUBAC™ device: 2-year clinical experience

Low back pain (LBP) due to degenerative disc disease (DDD) is a common condition that can be treated along a continuum of care: from conservative therapies to several surgical choices. Nucleus arthroplasty is an emerging technology that could potentially fill part of the gap in the spine continuum of care. The introduction of recent technologies that allow the replacement of the degenerated disc nucleus using prosthetic devices may be considered an additional therapeutic tool that can be used by the surgeon in selected cases of LBP due to DDD. Nucleus arthroplasties are designed to treat early stages of DDD, which are one of the most common spinal disorders in the population under 65 years of age. NUBAC™ is the first articulating nucleus disc prosthesis, designed to optimally respect the lumbar anatomy, kinematics, and biomechanics, constructed in unique two-piece manufactured from polyetheretherketone (PEEK) with an inner ball/socket articulation. The optimal indications for NUBAC™ implantation are: disc height >5 mm, degenerative disc changes at an early stage (Pfirmann 2, 3), single level affection, integrity of posterior facet joints, lack of local anatomical contraindication, failure of conservative treatment for at least 6 months. From December 2006 to January 2009, a total of 39 patients underwent nucleus disc arthroplasty with NUBAC™ device. 22 cases have 2-year follow up. There have been no major intra-operative or post-operative vascular or neurological complications in this series. The data showed that there were significant decreases in both Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) after the procedure, with a meaningful improvement of symptoms in all patients. Although preliminary, the initial results are encouraging. The absence of any major intra-operative and post-operative complications supports the design rationale of the NUBAC™, being less invasive comparing to total disc replacement (TDA) and with a low rate of surgical risk. The effectiveness of data as seen in 2-year follow-up on both VAS and ODI have also suggested that the NUBAC™ could be considered a viable treatment option for patients with LBP caused by DDD

The international spine registry SPINE TANGO: status quo and first results

With an official life time of over 5 years, Spine Tango can meanwhile be considered the first international spine registry. In this paper we present an overview of frequency statistics of Spine Tango for demonstrating the genesis of questionnaire development and the constantly increasing activity in the registry. Results from two exemplar studies serve for showing concepts of data analysis applied to a spine registry. Between 2002 and 2006, about 6,000 datasets were submitted by 25 centres. Descriptive analyses were performed for demographic, surgical and follow-up data of three generations of the Spine Tango surgery and follow-up forms. The two exemplar studies used multiple linear regression models to identify potential predictor variables for the occurrence of dura lesions in posterior spinal fusion, and to evaluate which covariates influenced the length of hospital stay. Over the study period there was a rise in median patient age from 52.3 to 58.6 years in the Spine Tango data pool and an increasing percentage of degenerative diseases as main pathology from 59.9 to 71.4%. Posterior decompression was the most frequent surgical measure. About one-third of all patients had documented follow-ups. The complication rate remained below 10%. The exemplar studies identified “centre of intervention” and “number of segments of fusion” as predictors of the occurrence of dura lesions in posterior spinal fusion surgery. Length of hospital stay among patients with posterior fusion was significantly influenced by “centre of intervention”, “surgeon credentials”, “number of segments of fusion”, “age group” and “sex”. Data analysis from Spine Tango is possible but complicated by the incompatibility of questionnaire generations 1 and 2 with the more recent generation 3. Although descriptive and also analytic studies at evidence level 2++ can be performed, findings cannot yet be generalised to any specific country or patient population. Current limitations of Spine Tango include the low number and short duration of follow-ups and the lack of sufficiently detailed patient data on subgroup levels. Although the number of participants is steadily growing, no country is yet represented with a sufficient number of hospitals. Nevertheless, the benefits of the project for the whole spine community become increasingly visible

Paternally inherited microdeletion at 15q11.2 confirms a significant role for the SNORD116 C/D box snoRNA cluster in Prader–Willi syndrome

Prader–Willi syndrome (PWS) is a neurobehavioral disorder manifested by infantile hypotonia and feeding difficulties in infancy, followed by morbid obesity secondary to hyperphagia. It is caused by deficiency of paternally expressed transcript(s) within the human chromosome region 15q11.2. PWS patients harboring balanced chromosomal translocations with breakpoints within small nuclear ribonucleoprotein polypeptide N ( SNRPN ) have provided indirect evidence for a role for the imprinted C/D box containing small nucleolar RNA (snoRNA) genes encoded downstream of SNRPN . In addition, recently published data provide strong evidence in support of a role for the snoRNA SNORD116 cluster (HBII-85) in PWS etiology. In this study, we performed detailed phenotypic, cytogenetic, and molecular analyses including chromosome analysis, array comparative genomic hybridization (array CGH), expression studies, and single-nucleotide polymorphism (SNP) genotyping for parent-of-origin determination of the 15q11.2 microdeletion on an 11-year-old child expressing the major components of the PWS phenotype. This child had an ∼236.29 kb microdeletion at 15q11.2 within the larger Prader–Willi/Angelman syndrome critical region that included the SNORD116 cluster of snoRNAs. Analysis of SNP genotypes in proband and mother provided evidence in support of the deletion being on the paternal chromosome 15. This child also met most of the major PWS diagnostic criteria including infantile hypotonia, early-onset morbid obesity, and hypogonadism. Identification and characterization of this case provide unequivocal evidence for a critical role for the SNORD116 snoRNA molecules in PWS pathogenesis. Array CGH testing for genomic copy-number changes in cases with complex phenotypes is proving to be invaluable in detecting novel alterations and enabling better genotype–phenotype correlations