Prader-Willi syndrome

To complement the 2005 Annual Clinical Focus on medical genomics, AFP is publishing a series of short reviews on genetic syndromes. This series was designed to increase awareness of these diseases so that family physicians can recognize and diagnose children with these disorders and understand the type of care they might require in the future. This review discusses Prader-Willi syndrome.     

Olecranon fractures: factors influencing re-operation

Purpose

We evaluated factors influencing re-operation in tension band and plating of isolated olecranon fractures.

Methods

Four hundred eighty-nine patients with isolated olecranon fractures who underwent tension band (TB) or open reduction internal fixation (ORIF) from 2003 to 2013 were identified at an urban level 1 trauma centre. Medical records were reviewed for patient information and complications, including infection, nonunion, malunion, loss of function or hardware complication requiring an unplanned surgical intervention. Electronic radiographs of these patients were reviewed to identify Orthopaedic Trauma Association (OTA) fracture classification and patients who underwent TB or ORIF.

Results

One hundred seventy-seven patients met inclusion criteria of isolated olecranon fractures. TB was used for fixation in 43 patients and ORIF in 134. No statistical significance was found when comparing complication rates in open versus closed olecranon fractures. In a multivariate analysis, the key factor in outcome was method of fixation. Overall, there were higher rates of infection and hardware removal in the TB compared with the ORIF group.

Conclusions

Our results demonstrate that the dominant factor driving re-operation in isolated olecranon fractures is type of fixation. When controlling for all variables, there is an increased chance of re-operation in patients with TB fixation.     

Customised osteotomy guides and endoprosthetic reconstruction for periacetabular tumours

Purpose

We sought to analyse clinical and oncological outcomes of patients after guided resection of periacetabular tumours and endoprosthetic reconstruction of the remaining defect.

Methods

From 1988 to 2008, we treated 56 consecutive patients (mean age 52.5 years, 41.1 % women). Patients were followed up either until death or February 2011 (mean follow up 5.5 years, range 0.1–22.5, standard deviation ± 5.3). Kaplan–Meier analysis was used to estimate survival rates.

Results

Disease-specific survival was 59.9 % at five years and 49.7 % at ten and 20 years, respectively. Wide resection margins were achieved in 38 patients, whereas 11 patients underwent marginal and seven intralesional resection. Survival was significantly better in patients with wide or marginal resection than in patients with intralesional resection (p = 0.022). Survival for patients with secondary tumours was significantly worse than for patients with primary tumours (p = 0.003). In 29 patients (51.8 %), at least one reoperation was necessary, resulting in a revision-free survival of 50.5 % at five years, 41.1 % at ten years and 30.6 % at 20 years. Implant survival was 77.0 % at five years, 68.6 % at ten years and 51.8 % at 20 years. A total of 35 patients (62.5 %) experienced one or more complications after surgery. Ten of 56 patients (17.9 %) experienced local recurrence after a mean of 8.9 months. The mean postoperative Musculoskeletal Tumor Society (MSTS) score was 18.1 (60.1 %).

Conclusion

The surgical approach assessed in this study simplifies the process of tumour resection and prosthesis implantation and leads to acceptable clinical and oncological outcomes.     

Prospective evaluation of intra-observer variability of the hydronephrosis index in sonographic examination of 44 patients with acute renal colic

Purpose

The aim of our prospective designed study was to confirm the intra-observer agreement of assessments of the hydronephrosis index (HI) with a sonographic technique that potentially provides additional information in patients with acute renal colic (ARC).

Methods

Sonographic measurement of HI and valuation of common clinical criteria were performed in 44 consecutive patients presenting with unilateral stone-related ARC. HI of colic side was recorded twice in predefined time intervals. Intra-observer agreement was evaluated with the Spearman’s rank correlation/rho (ρ) for attributive-metric characteristics. Data of HI-measurement on the colic side were compared with data of the unaffected side using t test.

Results

Intra-observer agreement was significant for HI in the colic side (ρ = 0.918, p < 0.001) and in the unaffected side (ρ = 0.826, p < 0.001). The mean HI between colic and unaffected side differed significantly on the first evaluation (85.2 vs. 93.7, respectively; p < 0.001) and on the second evaluation (85.1 vs. 93.6, respectively; p < 0.001) as well.

Conclusions

The HI method is a slightly feasible examination method in patients presenting with stone-related renal colic. Moreover, it offers a solid discrimination between obstruction and non-obstruction. Our prospective trial illustrates HI as a reproducible method with a high-grade intra-observer agreement. However, potential change of values under medical expulsive therapy and coherency with the functionality of the obstructed kidney may lead to bias and therefore remain to be analyzed. Further studies to specify exact thresholds for this method and to state our findings are required.     

In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom‐made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate‐coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull‐out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull‐out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:606–612, 2014.     

Posterior-only correction of Scheuermann kyphosis using pedicle screws: economical optimization through screw density reduction

Introduction

Posterior-only approach using pedicle screws’ fixation has emerged as the preferred surgical technique for Scheuermann kyphosis (SK) correction. Insertion of multiple pedicle screws while increasing stability increases also the risk of complications related to screw malpositioning and surgical cost. The optimal screw density required in surgical correction of SK remains unclear. This study compares the safety and efficacy of low screw density (LSD) versus high screw density (HSD) technique used in posterior-only correction of SK.

Methods

Twenty-one patients underwent surgical correction of SK between 2007 and 2011 and were reviewed after a mean of 29 months. HSD technique (i.e., 100 % of available pedicles, averaged 25.2 ± 4 screws) was used in 10 cases and LSD technique (i.e., 54–69 % of available pedicles in a pre-determined pattern, averaged 16.8 ± 1.3 screws; p < 0.001) was used in 11 cases. Kyphosis correction was assessed by comparing thoracic kyphosis, lumbar lordosis and sagittal balance on preoperative and postoperative radiographs. Cost saving analysis was performed for each group.

Results

Preoperative thoracic kyphosis, lumbar lordosis and sagittal balance were similar for both groups. The average postoperative kyphosis correction was similar in both HSD and LSD groups (29° ± 9° vs. 34° ± 6°, respectively; p = 0.14). Complication occurred in four patients (19 %) in the HSD group and in two patients (9 %) in the LSD group (p = 0.56). Three patients required re-operation. Compared to HSD using LSD saves 4,200£ per patient in hardware and 88,200£ for the entire cohort.

Conclusion

LSD technique is as safe and effective as HSD technique in posterior-only correction of SK. Implant-related cost could be reduced by 32 %.     

Bild gebende Verfahren in der Unfallchirurgie – Konsensuskonferenz

Trauma und Berufskrankheit - Ziel der Konsensuskonferenz war es, den aktuellen Wissensstand zur Indikationsstellung Bild gebender Verfahren in der Unfallchirurgie für die Regionen Hand, Knie...     

Human exposure to airborne aniline and formation of methemoglobin: a contribution to occupational exposure limits

Aniline is an important starting material in the manufacture of polyurethane-based plastic materials. Aniline-derived methemoglobinemia (Met-Hb) is well described in exposed workers although information on the dose–response association is limited. We used an experimental design to study the association between aniline in air with the formation of Met-Hb in blood and the elimination of aniline in urine. A 6-h exposure of 2 ppm aniline in 19 non-smoking volunteers resulted in a time-dependent increase in Met-Hb in blood and aniline in urine. The maximum Met-Hb level in blood (mean 1.21 ± 0.29 %, range 0.80–2.07 %) and aniline excretion in urine (mean 168.0 ± 51.8 µg/L, range 79.5–418.3 µg/L) were observed at the end of exposure, with both parameters rapidly decreasing after the end of exposure. After 24 h, the mean level of Met-Hb (0.65 ± 0.18 %) returned to the basal level observed prior to the exposure (0.72 ± 0.19 %); whereas, slightly elevated levels of aniline were still present in urine (means 17.0 ± 17.1 vs. 5.7 ± 3.8 µg/L). No differences between males and females as well as between slow and fast acetylators were found. The results obtained after 6-h exposure were also comparable to those observed in four non-smoking volunteers after 8-h exposure. Maximum levels of Met-Hb and aniline in urine were 1.57 % and 305.6 µg/L, respectively. Overall, our results contribute to the risk assessment of aniline and as a result, the protection of workers from aniline-derived adverse health effects at the workplace.