[Scoliosis in spinal muscular atrophy]. / Skoliose bei spinaler Muskelatrophie.

5q-spinal muscular atrophy (5q-SMA) is an autosomal recessive neuromuscular disorder caused by a biallelic mutation of the survival of motor neuron 1 SMN1 gene. The resulting lack of SMN protein causes a progressive degeneration of anterior motor neurons and muscular atrophy, which leads to a progressive scoliosis in two-thirds of affected cases. Depending on the disease subtype and severity, affected patients can subsequently develop respiratory insufficiency, leading to a fatal outcome. Ground-breaking research on this devastating disorder has led to the approval of novel therapies that may alter the clinical course of this disease in the future. Here we present a summary of these new therapies, current operative strategies for 5q-SMA associated scoliosis and provide an outlook for possible implications for the future.

Single-source dual-energy computed tomography for the detection of bone marrow lesions: impact of iterative reconstruction and algorithms.

PURPOSE: To compare the diagnostic performance of different reconstruction algorithms of single-source dual-energy computed tomography (DECT) for the detection of bone marrow lesions (BML) in patients with vertebral compression fracture using MRI as the standard of reference. MATERIAL AND METHODS: Seventeen patients with an age over 50 who underwent single-source DECT of the spine were included. The raw data (RD) were reconstructed using filtered back-projection (FBP) and iterative reconstruction (IR) with three iteration levels (IR1-IR3). Bone marrow images were generated using a three-material decomposition (3MD) and a two-material decomposition (2MD) algorithm and an RD-based approach. Three blinded readers scored the images for image quality and the presence of bone marrow lesions (BML). Only vertebrae with height loss were included. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The different reconstructions were compared using Dunn's multiple comparison test. RESULTS: Thirty-nine vertebrae were included. IR(1-3) showed superior sensitivity (87.5%) compared to FBP (75%) using 3MD but was comparable to RD (83.3%). All 2MD images were inferior (sensitivity < 38%). The image quality score was significantly higher for 3MD-IR(1-3) compared to 3MD-FBP (p < 0.0001) and all 2MD data sets (p < 0.03). This pattern was also supported by the SNR and CNR measurements. RD showed no significant improvement compared to IR. CONCLUSION: The image quality of bone marrow images acquired with DECT can be improved by using IR compared with FBP. RD-based reconstruction does not offer significant improvement over image data-based reconstruction. 2MD algorithms are not suitable for BML detection.

Unexpected positive cultures in presumed aseptic revision spine surgery using sonication.

AIMS: During revision procedures for aseptic reasons, there remains a suspicion that failure may have been the result of an undetected subclinical infection. However, there is little evidence available in the literature about unexpected positive results in presumed aseptic revision spine surgery. The aims of our study were to estimate the prevalence of unexpected positive culture using sonication and to evaluate clinical characteristics of these patients. PATIENTS AND METHODS: All patients who underwent a revision surgery after instrumented spinal surgery at our institution between July 2014 and August 2016 with spinal implants submitted for sonication were retrospectively analyzed. Only revisions presumed as aseptic are included in the study. During the study period, 204 spinal revisions were performed for diagnoses other than infection. In 38 cases, sonication cultures were not obtained, leaving a study cohort of 166 cases. The mean age of the cohort was 61.5 years (sd 20.4) and there were 104 female patients. RESULTS: Sonication cultures were positive in 75 cases (45.2%). Hardware failure was the most common indication for revision surgery and revealed a positive sonication culture in 26/75 cases (35%) followed by adjacent segment disease (ASD) in 23/75 cases (30%). Cutibacterium acnes and Staphylococcus epidermidis were the most commonly isolated microorganisms, observed in 45% and 31% of cases, respectively. C. acnes was isolated in 65.2% of cases when the indication for revision surgery was ASD. CONCLUSION: Infection must always be considered as a possibility in the setting of spinal revision surgery, especially in the case of hardware failure, regardless of the lack of clinical signs. Sonication should be routinely used to isolate microorganisms adherent to implants. Cite this article: Bone Joint J 2019;101-B:621-624.

Mid-Term Survival of Total Knee Arthroplasty in Patients with Posttraumatic Osteoarthritis.

PURPOSE OF THE STUDY There is limited evidence on survival and complication rates in patients after total knee arthroplasty for posttraumatic osteoarthritis. The failure mechanisms leading to revision remain an issue of constant debate. The purpose of this study was to analyze the mid-term survival of primary total knee arthroplasties as well as to evaluate complications and failure mechanisms in patients with posttraumatic knee osteoarthritis. MATERIAL AND METHODS This retrospective study included 79 patients with an average age of 59 years at the time of primary total knee arthroplasty. A functional and radiographic assessment was obtained during outpatient clinical follow-up at 3 and 12 months postoperatively and yearly intervals after that. Survival rates were calculated using Kaplan-Meier analyses. The mean postoperative follow-up was 69 months. RESULTS At 69 month the revision-free survival rate was 88.6%. In nine cases (11.4%) a revision procedure was performed. The leading cause of revision was a periprosthetic infection (n = 6, 66.6%). An age of fewer than 55 years at the time of total knee arthroplasty had a significant influence on implant survival (p = 0.018) with superior survival in favor of the older patient population. At most recent follow-up, a mean Knee Society Score of 82 points and an average Function Score of 77 points were observed. CONCLUSIONS Periprosthetic joint infection is the primary failure mechanism leading to a revision in patients with total knee arthroplasty for posttraumatic osteoarthritis. Apart from the increased infection rate, total knee arthroplasties in patients with posttraumatic osteoarthritis revealed results that were comparable to patients with primary osteoarthritis. Key words:posttraumatic knee osteoarthritis, total knee replacement, survival, complications, revision, outcome.

Microstructural Changes of Tensor Fasciae Latae and Gluteus Medius Muscles Following Total Hip Arthroplasty: A Prospective Trial.

PURPOSE OF THE STUDY Although total hip arthroplasty (THA) is one of the most successful orthopedic operations, the soft tissue trauma towards the periarticular musculature during surgical approaches remains a critical concern. However, the actual microstructural proof of muscle trauma on the level of the myofiber due to the surgical approach has never been claimed. MATERIAL AND METHODS Patients undergoing THA were prospectively enrolled and either operated by a direct lateral (DL) or a anterolateral minimally invasive approach (ALMI). Intraoperatively and at 6 months follow-up a needle biopsy was taken from the gluteus medius muscle and the tensor fasciae latae. Pre- and post-operative fiber diameter and composition, of gluteal medius muscle (GMM) and the tensor fasciae latae muscle (TFLM) were compared in both surgical approaches. RESULTS A total of 19 patients (12 F; 7 M) were included in this study. The average pre-operative fiber diameter or fiber type composition did not differ significantly in the GMM and TFLM, nor did it vary among patients with different approaches. The muscle fiber diameter significantly increased post-operatively in the TFLM, in both, the DL (p = 0.043) and the ALMI (p = 0.043) approach. There was a trend towards more pronounced muscle fiber changes in the DL (TFLM: p = 0.077; GMM: p = 0.150), compared to the ALMI. DISCUSSION AND CONCLUSIONS Our results show microstructural changes to the periarticular musculature following THA by a compensatory hypertrophy of the TFLM and GMM. These adaptions directly next to the surgical trauma were observed in DL and AMLI. Key words: total hip arthroplasty, skeletal muscle, muscle biopsy, iatrogenic trauma, muscle scar.

Dual-energy CT virtual non-calcium technique for detection of bone marrow edema in patients with vertebral fractures: A prospective feasibility study on a single- source volume CT scanner.

OBJECTIVES: Dual-energy computed tomography (DECT) is a recent development for detecting bone marrow edema (BME) in patients with vertebral compression fractures. The aim of this pilot study was to determine the reliability of single-source DECT in detecting vertebral BME using magnetic resonance imaging (MRI) as standard of reference. MATERIALS AND METHODS: Nine patients with radiographic thoracic or lumbar vertebral compression fractures underwent both, DECT on a 320-row single-source scanner and 1.5T MRI. Virtual non-calcium (VNC) images were reconstructed from the DECT volume datasets. Three blinded readers independently scored images for the presence of BME. Only vertebrae with loss of height in radiography (target vertebrae) were included in the analysis. A vertebra was counted as positive if two readers agreed on the presence of BME. Cohen's kappa was calculated for interrater comparison. Intervertebral ratios of target and the reference vertebra were compared for CT attenuation and MR signal intensity in a reference vertebra using Spearman correlation. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. RESULTS: Fourteen target vertebrae with a radiographic height loss were identified; eight of them showed BME on MRI, while DECT identified BME in 7 instances. There were no false positive virtual non-calcium images, resulting in a sensitivity of 0.88 (0.75-1.0 among all readers) and specificity of 1.0 (0.81-1.0). Interrater agreement was inferior for DECT (κ=0.63-0.89) compared to MRI (κ=0.9-1.0). Intervertebral ratio in VNC images strongly correlated with short-tau inversion recovery (r=0.87) and inversely with T1 (-0.89). SNR (0.2+/- 0.2 in VNC and 16.7+/- 7.3 in STIR) and CNR (0.2+/- 0.3 and 7.1+/- 6.3) values were inferior in VNC. CONCLUSIONS: Detecting BME with single-source DECT is feasible and allows detection of vertebral compression fractures with reasonably high sensitivity and specificity. However, image quality of VNC reconstructions has to be improved to achieve better interrater agreement. Nonetheless, DECT might accelerate the diagnostic work-flow in patients with vertebral compression fractures in the future and reduce the number of additional MRI examinations.

[Solitary spinal metastases. Is aggressive surgical management justified?]. / Solitäre Metastasen der Wirbelsäule. Indikationen für eine aggressive chirurgische Therapie?

Advances in oncological and surgical therapies have led to a significant increase in life expectancy of cancer patients and also prolonged survival of patients with isolated or multiple metastases. Among the skeletal manifestations the spine is the most often affected site. Using novel imaging techniques with higher resolution and use of metabolic signatures, the screening of cancer patients has improved considerably. Consequently, the diagnosis of metastases is becoming increasingly more sensitive. Therefore, but also due to more effective polychemotherapy protocols, singular or solitary metastases are more frequently observed either in the early stages or as a result of a controlled malignant tumor entity (stable disease). The questions whether a solitary metastasis really exists (illusion or reality?) and its radical oncological and surgical treatment as a circumscribed singular tumor manifestation, is really relevant for the overall prognosis, remains controversial. However, it seems evident that a biologically favorable underlying tumor biology, radical treatment of the primary tumor and a long metastasis-free interval are valid predictors of a good oncological outcome. In the presence of a solitary metastasis under these circumstances (typical example: solitary metastasis of renal cell carcinoma many years after radical tumor nephrectomy) a radical surgical procedure (en bloc spondylectomy) can significantly improve the long-term prognosis of this patient group in combination with adjuvant chemotherapy and/or radiotherapy. However, a thorough evaluation of the overall survival prognosis, a detailed and complete staging followed by a treatment consensus in the interdisciplinary tumor board has to precede any therapeutical decisions.

Clinical predictors of surgical outcome in cervical spondylotic myelopathy: an analysis of 248 patients.

The purpose of this study was to investigate the clinical predictors of surgical outcome in patients with cervical spondylotic myelopathy (CSM). We reviewed a consecutive series of 248 patients (71 women and 177 men) with CSM who had undergone surgery at our institution between January 2000 and October 2010. Their mean age was 59.0 years (16 to 86). Medical records, office notes, and operative reports were reviewed for data collection. Special attention was focused on pre-operative duration and severity as well as post-operative persistence of myelopathic symptoms. Disease severity was graded according to the Nurick classification. Our multivariate logistic regression model indicated that Nurick grade 2 CSM patients have the highest chance of complete symptom resolution (p < 0.001) and improvement to normal gait (p = 0.004) following surgery. Patients who did not improve after surgery had longer duration of myelopathic symptoms than those who did improve post-operatively (17.85 months (1 to 101) vs 11.21 months (1 to 69); p = 0.002). More advanced Nurick grades were not associated with a longer duration of symptoms (p = 0.906). Our data suggest that patients with Nurick grade 2 CSM are most likely to improve from surgery. The duration of myelopathic symptoms does not have an association with disease severity but is an independent prognostic indicator of surgical outcome.

[Biomechanical aspects of complex reconstructions following radical resection of thoracolumbar spinal tumors]. / Biomechanische Aspekte radikaler Resektionen und deren Rekonstruktion an der thorakolumbalen Wirbelsäule.

The total number of spinal tumors has increased over the past decade. However, the average survival time of tumor patients has increased due to improvements in the multidisciplinary treatment regimes. Therefore, radical tumor resection and complex reconstruction were developed in spinal surgery. Various reconstructive options for the throracolumbar spine are nowadays available and are depicted in this article. The success of complex reconstructive surgery relies on biomechanical principles and reconstruction is dependent on the size and location of the lesion, bone porosity and implant systems used. Special emphasis of this article focuses on en bloc vertebrectomy which is the most radical approach of spinal tumor surgery. The biomechanical aspects of different types of lesions and the reconstructive options are discussed in the context of the currently published literature.

National in-hospital morbidity and mortality trends after lumbar fusion surgery between 1998 and 2008.

Increasing numbers of posterior lumbar fusions are being performed. The purpose of this study was to identify trends in demographics, mortality and major complications in patients undergoing primary posterior lumbar fusion. We accessed data collected for the Nationwide Inpatient Sample for each year between 1998 and 2008 and analysed trends in the number of lumbar fusions, mean patient age, comorbidity burden, length of hospital stay, discharge status, major peri-operative complications and mortality. An estimated 1 288 496 primary posterior lumbar fusion operations were performed between 1998 and 2008 in the United States. The total number of procedures, mean patient age and comorbidity burden increased over time. Hospital length of stay decreased, although the in-hospital mortality (adjusted and unadjusted for changes in length of hospital stay) remained stable. However, a significant increase was observed in peri-operative septic, pulmonary and cardiac complications. Although in-hospital mortality rates did not change over time in the setting of increases in mean patient age and comorbidity burden, some major peri-operative complications increased. These trends highlight the need for appropriate peri-operative services to optimise outcomes in an increasingly morbid and older population of patients undergoing lumbar fusion.