Intraspinal mesenchymal chondrosarcoma in a 14-year-old patient: diagnostic and therapeutic problems in relation to the review of literature

Mesenchymal chondrosarcoma (MC) is an infrequent, highly malignant neoplasm of the soft tissues and bone. It is very rare in the pediatric age group, especially in the intraspinal location. Only 24 cases have been reported to date. The authors present a case of a 14-year-old boy with an intraspinal MC who died of the disease 50 months from the initial diagnosis and after the third local recurrence. The patient was treated with a combination of chemotherapy, radiotherapy, and surgery. The authors review the clinical presentation, diagnostics, and the efficacy of treatment of pediatric patients with MC reported in the literature from 1978 to 2010.     

Bioabsorbable fixation: scientific, technical, and clinical concepts

Bioabsorbable internal fixation has been clinically available for nearly 20 years and has been used for hard tissue and/or soft tissue fixation from the head to toe. During this time, there has been a rapid evolution in bioabsorbable polymers as well as in the implants and their clinical applications. There is a plethora of bioabsorbable polymers now available for clinical use, and although all are related chemically, seemingly small changes in formulation can have a dramatic effect on their biomechanical and physiological properties. This article summarizes much of the relevant scientific, technical, and clinical literature in a simple, straightforward manner to help surgeons better understand and appreciate the nuances of bioabsorbable fixation. This up-to-date review should also help researchers establish a baseline of knowledge that can provide a platform for further developments in this exciting field.     

A resorbable rivet system for pediatric craniofacial surgery: biomechanical testing and clinical experience

The use of a new method of bone fixation for pediatric craniofacial surgery was evaluated by both biomechanical tests and clinical use. A "pull-back" rivet composed of 82% poly-L-lactic acid and 18% polyglycolic acid (LactoSorb) for use with resorbable plates was developed to obviate the traditional hand-tapping technique used for the placement of resorbable screws. In in vitro testing, the average failure load of the rivets in uniaxial pullout was nearly 50 kg and approximately 75 kg in shear. Approximately two thirds of their initial strength was retained by 6 weeks. In clinical testing, 10 patients undergoing cranial vault reconstruction were treated by 1.5-mm resorbable plates secured by rivets. Although postoperative clinical outcomes were unaffected, good engagement of the devices with secure plate fixation was obtained in only about 70% of the rivets fired.Although the novel approach of a pull-back rivet was encouraging in both design and in vitro testing, its clinical use is impaired by the sensitivity of the device to the thickness of the bone into which it is placed, as well as its larger diameter compared with resorbable screws.     

Assay of bone morphogenetic protein-2, -4, and -7 in human demineralized bone matrix

Demineralized bone matrix (DBM) is a widely used bone graft material that derives its osteoinductive potential from matrix-associated bone morphogenetic proteins (BMPs). Prior investigations have shown that the osteoinductive potential can vary widely, with influence from both donor and processing sources. Although it is plausible that donor variance in the BMP profile can be an important consideration, the few published studies available have given inconsistent and incomplete information about this. The goal was to (1) characterize the variance of BMP-2, BMP-4, and BMP-7 in fully demineralized DBM derived from 20 appropriately screened (Food and Drug Administration and the American Association of Tissue Banks criteria) donors (male and female, 17-65 years) and (2) using literature review, infer the potential for this to be an important source of variability in graft function. BMPs were extracted with 4 M guanidine hydrochloride, and levels of BMP-2, BMP-4, and BMP-7 were measured using enzyme-linked immunosorbent assay. Measured levels were as follows: BMP-2 = 21.4 +/- 12.0 ng/g DBM, BMP-4 = 5.45 +/- 2.04 ng/g DBM, and BMP-7 = 84.1 +/- 34.4 ng/g DBM, which were significantly different (P < 0.05). There was a positive linear correlation between BMP-2 and BMP-7 (P = 0.0227). DBM derived from female donors had significantly greater concentrations of BMP-2 and BMP-7 than did that derived from male donors (P = 0.0257 and 0.0245, respectively). There was no significant correlation between donor age and the levels of any of the measured BMPs. The magnitude of variance of BMP profile appears to reasonably well correspond to the variance in osteoinductive potential cited by others, suggesting the possibility of using this as a method of donor screening.     

The effect of high temperature intraoperative molding on bioabsorbable PLLA-PGA craniofacial fixation

Bioabsorbable internal fixation has become an established part of the surgeons' armamentarium. There are several unique aspects of bioabsorbable polymers that can enhance their versatility. One of these is the application of heat to adapt the implant. Hot-tip cautery has been used for years to cut and otherwise customize bioabsorbable implants intraoperatively. As the tips of these devices can reach temperatures of over 1,000 degrees C, there is the potential that such practice can modify the degradation properties of these polymers. This study was performed to better understand the extent to which this potential exists. Screw heads of an 82:18 poly-L-lactic acid and poly-glycolic acid copolymer were modified by repeated passage of a hot-tip cautery wire, deforming the hex geometry to that of a ball. There was no significant difference between the glass transition temperature (approximately 59 degrees C) and inherent viscosity (approximately 1.45 dL/g) of treated and untreated screw heads, indicating no overall change in these properties throughout the mass of the screw head. Additionally, these properties were measured and comparisons made between the treated screw heads and untreated plates made of the same polymer during 28-day exposure to an in vitro bath (pH 7.4, 37 degrees C). The glass transition temperature and inherent viscosity exhibited declines during this period, with no significant differences between the two groups. Collectively, these results suggest that hot-tip cautery results in no substantial changes in the degradation characteristics of this polymer.     

Non-dipping and arterial hypertension depend on clinical factors rather than on genetic variability of ACE and RGS2 genes in patients with type 1 diabetes

The aim of our study was to characterize the association of clinical and genetic risk factors such as: ACE genotype (rs17997552, rs1800764, rs4459609) and RGS2 (rs2746071) with the development of hypertension (HT) and non-dipping phenomenon in patients with type 1 diabetes mellitus (T1DM). A total of 238 adolescents and young adults with T1DM—103 females and 135 males, aged 8–30 years (mean 17.35 ± 5.2) with diabetes duration 1–26 years (mean 7.72 ± 6.2), with mean HbA1c (IFCC) 58 ± 15 mmol/mmol—were subjected to 24-h ambulatory blood pressure measurements (ABPM). The results of the ABPM were analyzed in association with the polymorphisms of ACE and RGS2 genes and clinical data of patients. HT was recognized in 65 (27 %) and non-dipping in 111 (46.63 %) patients. In the multivariate analysis of factors predisposing to HT, the variables that remained significant were the following: male sex (OR 1.62; 95 % CI 1.171–2.250), non-dipping (OR 1.40; 95 % CI 1.03–1.90) and total cholesterol level (OR 1.01; 95 % CI 1.005–1.021). The only factor influencing non-dipping was the duration of diabetes—OR 1.09 (95 % CI 1.04–1.14). The patients displaying non-dipping have a twice increased risk of development of HT (OR 2.17; 95 % CI 1.21–3.89). There was no association between disturbances of blood pressure (BP) and genotypes of ACE: rs17997552, rs1800764, rs4459609 and RGS2: rs2746071. Clinical rather than genetic risk factors seem to be connected with BP disturbances in young patients with T1DM. Although we have identified representative groups of HT versus non-HT and dipping versus non-dipping subjects, the effect of genetic predisposition to the development of higher BP is too weak to be statistically significant.     

Non‐ablative 1550‐nm erbium‐glass and ablative 10 600‐nm carbon dioxide fractional lasers for acne scars: a randomized split‐face study with blinded response evaluation

Background Non‐ablative 1550‐nm erbium‐doped fractional photothermolysis systems (FPS) and 10 600‐nm carbon dioxide fractional laser systems (CO₂ FS) have been effectively used to treat scars. Objective We compared the efficacy and safety of single‐session treatments of FPS and CO₂ FS for acne scars through a randomized, split‐face, evaluator‐blinded study. Methods Eight patients with acne scars were enrolled in this study. Half of each subject’s face was treated with FPS and the other half was treated with CO₂ FS. We used a quartile grading scale for evaluations. Results At 3 months after the treatment, the mean grade of improvement based on clinical assessment was 2.0 ± 0.5 for FPS and 2.5 ± 0.8 for CO₂ FS. On each side treated by FPS and CO₂ FS, the mean duration of post‐therapy crusting and scaling was 2.3 and 7.4 days respectively and that of post‐therapy erythema was 7.5 and 11.5 days respectively. The mean VAS pain score was 3.9 ± 2.0 with the FPS and 7.0 ± 2.0 with the CO₂ FS. Conclusion We demonstrated the efficacy and safety of single‐session acne scar treatment using FPS and CO₂ FS in East Asian patients. We believe that our study could be used as an essential reference when choosing laser modalities for scar treatment.