Clinical outcome after dorso-ventral stabilization of the thoracolumbar and lumbar spine with vertebral body replacement and dorsal stabilization.

PURPOSE: Surgical stabilization of the spine by vertebral body replacement (VBR) is used for spinal disorders such as traumatic fractures to provide an anatomical re-adjustment of the spine to prevent late detrimental effects and pain [1-4]. This study addresses the clinical outcome after a ventral intervention with VBR and bisegmental fusion. METHODS: The study includes 76 patients (mean age: 59.34 ± 15.97; 34 females and 42 males) with fractures in the lower thoracic and lumbar spine. They were selected from patients of our hospital who received an anterolateral VBR surgery on the corresponding lower spine region over a nine-year period. Only patients were examined with X-rays and complete follow-up records. Exclusion criteria were changes due to degeneration and pathological fractures. Patients were divided into two groups, the thoracotomy group (Th10-L1) and the lumbotomy group (L2-5), respectively. Minimum one year after surgery, patients were asked about their well-being using a precasted questionnaire. RESULTS: No significant differences with respect to the subjective impression of the patients concerning their back pain, spinal functional impairment, their general functional status and their quality of life impairment. Unfortunately, however, only a rather modest but significant increase of the post-surgical life quality was reported. CONCLUSIONS: Patients who underwent VBR in the lower thoracic or lumbar spine show modest long-term well-being. The results suggest that injuries to the lower thoracic or lumbar spine requiring vertebral body replacement should be classified as severe injuries since they adversely affect the patients' long-term well-being. TRIAL REGISTRATION: Study of clinical outcome of patients after vertebral body replacement of the ventral thoracal and lumbal spine, DRKS00031452. Registered 10th March 2023 - Prospectively registered. Trial registration number DRKS00031452.

C-reactive protein in spinal surgery: more predictive than prehistoric.

PURPOSE: In spinal surgery, surgical site infections (SSI) after dorsal spondylodesis lead to severe short- and long-term complications. Despite various clinical and serological evidence, the detection of a postoperative SSI remains crucial. In this retrospective cohort study, we determined the prognostic value of C-reactive protein (CRP) kinetics after open reduction and dorsal spondylodesis in the development of a SSI. METHODS: We retrospectively analyzed 192 patients from 2016 to 2018 undergoing open reduction and dorsal spondylodesis with and without SSI for 20 days at a level-I trauma center and assessed their serological and clinical characteristics. RESULTS: On day 7 and 8 after surgery, patients who developed a SSI displayed significantly higher CRP levels. A second peak after the initial maximum of CRP and a restricted failure to decline as well as a maximum CRP of more than 225 mg/l predict an infectious complication with a sensitivity of 92.9%, and a specificity of 78.2%. A binary logistic regression leads to 85.7% and 69.7%, respectively. A one-phase decay exponential regression can predict 75.6% of the variance after the initial peak of CRP. CONCLUSION: Our study demonstrates a high value of postoperative CRP kinetics in SSI detection after dorsal spondylodesis. Moreover, we observed typical CRP levels with a specific course as indicative predictors that may facilitate an early SSI detection in clinical practice.

[Posterior vertebral column resection for correction of kyphotic deformity due to osteoporotic fractures of the thoracic spine]. / Posterior vertebral column resection (PVCR) zur Korrektur von Hyperkyphosen bei osteoporotischen Frakturen der Brustwirbelsäule.

OBJECTIVE: The posterior vertebral column resection (PVCR) comprises a one-step resection of the vertebral body by a costotransversectomy together with a 360° spondylodesis. After removing the vertebral body, straightening of the existing kyphotic malposition is possible. INDICATIONS: Pronounced thoracic kyphosis after osteoporotic sintering fractures in one or more vertebral bodies. CONTRAINDICATIONS: General contraindications for surgical procedures, ASA >3 (American Society of Anesthesiologists). SURGICAL TECHNIQUE: First, dorsal stabilization of the vertebral column on at least two levels cranial and caudal of the VCR. Next, in a one-step procedure the laminectomy with costotransversectomy and the resection of the vertebral body is done. The ventral defect gap is filled by a mesh cage to provide ventral support. By compression the malposition is reduced and the mesh cage is fixed into position. Finally the vertebrae joints are opened up using a chisel and bone or bone substitute is placed to complete the 360° spondylodesis. POSTOPERATIVE MANAGEMENT: Functional treatment without peak load exercises as well as appropriate osteoporosis treatment. RESULTS: In a retrospective study 10 patients treated with this surgical technique were investigated. The results show a very good correction of the kyphotic maldeformity while the complications remain moderate.

[Pedicle subtraction osteotomy to correct rigid deformities]. / Pedikelsubtraktionsosteotomie zur Korrektur rigider Deformitäten.

OBJECTIVE: The aim of the surgery is to restore the sagittal profile in the event of a mismatch of the patient's spinopelvic parameters and high patient suffering. INDICATIONS: Clinically symptomatic sagittal imbalance due to degeneration, trauma or after spinal surgery which can not be adequately treated by conservative therapy. CONTRAINDICATIONS: Severe general disease of the patient; local or systemic inflammation. SURGICAL TECHNIQUE: A dorsal approach is used to resect the dorsal vertebral structures and to perform an osteotomy to the anterior edge of the spine. POSTOPERATIVE MANAGEMENT: Rest with a load limit of 5 kg for 3 months. Prohibition of deep sitting for this time. RESULTS: The pedicle subtraction osteotomy is described in the literature as a reliable method for the treatment of sagittal imbalance. The high rate of described complications should be discussed preoperatively with the patient.

Evaluation of ostarine as a selective androgen receptor modulator in a rat model of postmenopausal osteoporosis.

Selective androgen receptor modulators (SARMs) have shown beneficial effects on muscle wasting, general physical function and bone properties in male mammals. However, data on the effects of SARMs in postmenopausal osteoporotic bone are scarce. We evaluated the effects of the SARM drug ostarine on postmenopausal osteoporotic bone in a rat osteoporosis model. Ovariectomy was performed on 46 of 56 3-month-old female Sprague-Dawley rats. Eight weeks after ovariectomy, ostarine was orally administered daily for 5 weeks in dosages of 0.04 (low, OVX + Ost. 0.04), 0.4 (intermediate, OVX + Ost. 0.4), and 4 mg/kg (high, OVX + Ost. 4) body weight. Another ovariectomized group received no ostarine. Lumbar vertebrae and femora were removed for biomechanical, gene expression, ashing, and computer tomography analyses. Low dose showed no effects. The effects of intermediate and high doses were comparable overall. Improvements were mainly seen in structural properties such as bone mineral density and bone volume density. However, the effects in femora were superior to effects in vertebrae. Ostarine treatment for 5 weeks did not improve significantly biomechanical properties. mRNA expression of the receptor activator of NF-κB ligand decreased after treatment, and uterine weight increased. Serum levels of phosphorus increased following ostarine treatment in intermediate and high-dose groups. Short-term treatment of osteoporotic bone with ostarine leads to improvement of several microstructural bone indices. While we did not observe changes in biomechanics, it is conceivable that longer treatment may also improve biomechanical properties. Further studies are needed to characterize longer time effects and side effects of ostarine in osteoporosis.

Accuracy of Latarjet graft and screw position after using novel drill guide.

PURPOSE: For the success of Latarjet procedure a correct graft positioning is mandatory. Furthermore, the correct screw placement is important to avoid cartilage damage and soft tissue irritation. Due to a cadaveric experimental study, the accuracy of graft and screw positioning utilizing a novel drill guide for a minimal-invasive Latarjet procedure was analyzed. METHODS: Five human fresh-frozen shoulder specimens have been treated in accordance with the Congruent-Arc Latarjet technique using the glenoid bone loss set (Arthrex, Naples, FL, USA) with 3.75 mm cannulated screws throughout a 5 cm skin incision without detachment of the scapularis tendon. All procedures were performed by one single, experienced shoulder surgeon. The accuracy of graft and screw positioning was assessed due to a CT scan. RESULTS: A noticeable learning curve was noted during the study period as the first surgery took 45 min and the last 33 min. All grafts were correctly positioned with regard to the articular line of the glenoid surface. Impingement with the maximum head circumference was not encountered. The screw positions did not affect the suprascapular nerve. A damage of the graft was not noticed. CONCLUSIONS: The authors can recommend the usage of the new drill guide tested in this study. It seems to be beneficial in the Latarjet procedure and may ease correct graft positioning and prevent screw misplacement. Compared to fully arthroscopically performed Latarjet procedures it provides much steeper learning curve and seems technically easier and quicker to handle.

Cement augmentation versus extended dorsal instrumentation in the treatment of osteoporotic vertebral fractures: a biomechanical comparison.

AIMS: Loosening of pedicle screws is a major complication of posterior spinal stabilisation, especially in the osteoporotic spine. Our aim was to evaluate the effect of cement augmentation compared with extended dorsal instrumentation on the stability of posterior spinal fixation. MATERIALS AND METHODS: A total of 12 osteoporotic human cadaveric spines (T11-L3) were randomised by bone mineral density into two groups and instrumented with pedicle screws: group I (SHORT) separated T12 or L2 and group II (EXTENDED) specimen consisting of T11/12 to L2/3. Screws were augmented with cement unilaterally in each vertebra. Fatigue testing was performed using a cranial-caudal sinusoidal, cyclic (1.0 Hz) load with stepwise increasing peak force. RESULTS: Augmentation showed no significant increase in the mean cycles to failure and fatigue force (SHORT p = 0.067; EXTENDED p = 0.239). Extending the instrumentation resulted in a significantly increased number of cycles to failure and a significantly higher fatigue force compared with the SHORT instrumentation (EXTENDED non-augmented + 76%, p < 0.001; EXTENDED augmented + 87%, p < 0.001). CONCLUSION: The stabilising effect of cement augmentation of pedicle screws might not be as beneficial as expected from biomechanical pull-out tests. Lengthening the dorsal instrumentation results in a much higher increase of stability during fatigue testing in the osteoporotic spine compared with cement augmentation. Cite this article: Bone Joint J 2016;98-B:1099-1105.

[Cement augmentation on the spine : Biomechanical considerations]. / Zementaugmentation an der Wirbelsäule : Was ist biomechanisch zu beachten?

BACKGROUND: Vertebral compression fractures are the most common osteoporotic fractures. Since the introduction of vertebroplasty and screw augmentation, the management of osteoporotic fractures has changed significantly. AIMS: The biomechanical characteristics of the risk of adjacent fractures and novel treatment modalities for osteoporotic vertebral fractures, including pure cement augmentation by vertebroplasty, and cement augmentation of screws for posterior instrumentation, are explored. MATERIALS AND METHODS: Eighteen human osteoporotic lumbar spines (L1-5) adjacent to vertebral bodies after vertebroplasty were tested in a servo-hydraulic machine. As augmentation compounds we used standard cement and a modified low-strength cement. Different anchoring pedicle screws were tested with and without cement augmentation in another cohort of human specimens with a simple pull-out test and a fatigue test that better reflects physiological conditions. RESULTS: Cement augmentation in the osteoporotic spine leads to greater biomechanical stability. However, change in vertebral stiffness resulted in alterations with the risk of adjacent fractures. By using a less firm cement compound, the risk of adjacent fractures is significantly reduced. Both screw augmentation techniques resulted in a significant increase in the withdrawal force compared with the group without cement. Augmentation using perforated screws showed the highest stability in the fatigue test. DISCUSSION AND CONCLUSION: The augmentation of cement leads to a significant change in the biomechanical properties. Differences in the stability of adjacent vertebral bodies increase the risk of adjacent fractures, which could be mitigated by a modified cement compound with reduced strength. Screws that were specifically designed for cement application displayed greatest stability in the fatigue test.

The role of inter-prosthetic distance, cortical thickness and bone mineral density in the development of inter-prosthetic fractures of the femur: a biomechanical cadaver study.

It is becoming increasingly common for a patient to have ipsilateral hip and knee replacements. The inter-prosthetic (IP) distance, the distance between the tips of hip and knee prostheses, has been thought to be associated with an increased risk of IP fracture. Small gap distances are generally assumed to act as stress risers, although there is no real biomechanical evidence to support this. The purpose of this study was to evaluate the influence of IP distance, cortical thickness and bone mineral density on the likelihood of an IP femoral fracture. A total of 18 human femur specimens were randomised into three groups by bone density and cortical thickness. For each group, a defined IP distance of 35 mm, 80 mm or 160 mm was created by choosing the appropriate lengths of component. The maximum fracture strength was determined using a four-point bending test. The fracture force of all three groups was similar (p = 0.498). There was a highly significant correlation between the cortical area and the fracture strength (r = 0.804, p < 0.001), whereas bone density showed no influence. This study suggests that the IP distance has little influence on fracture strength in IP femoral fractures: the thickness of the cortex seems to be the decisive factor.

[Magnetic resonance imaging criteria for the differentiation of traumatic and non-traumatic rotator cuff tears]. / Kernspintomographische Kriterien zur Unterscheidung von traumatischen und nicht traumatischen Rotatorenmanscnerrenrupturen.

It is often not easy to classify a rotator cuff tear into traumatic or non-traumatic. For individual medical examinations the classification depends basically on the following four criteria: Case history, analysis of the accident, analysis of the complaints after the accident (or even before) and the pathomorphological findings. The aim of this study was to identify findings in the magnetic resonance imaging of the shoulder joints of patients with rotator cuff tears that could help in the differentiation of traumatic versus non-traumatic. As a result it could be shown that infraspinatus and subscapularis tears, Hill-Sachs lesions and fractures of the tuberculum majus are significantly more detectable among those patients reporting a trauma. In contrast degeneration of the supraspinatus tendon, calcific tendinitis of the supraspinatus tendon, ac-joint degeneration and an absence of the subacromial fat pad are more verifiable in the non-traumatic group. These results can be used as additional important information in the individual medical examination of patients with rotator cuff tears.

Within-field manipulation of potato leafhopper (Homoptera: Cicadellidae) and insect predator populations using an uncut alfalfa strip.

The effects of a 3-m wide uncut alfalfa strip on the within field distribution of Empoasca fabae (Harris) (Homoptera: Cicadellidae) and several species of insect predators were examined for 3 yr (1998-2000). The objectives were to determine whether this uncut strip would serve as a trap crop for E. fabae and a refuge for insect predators at first harvest. Empoasca fabae and insect predators in the families Coccinellidae, Nabidae, Anthocoridae, Chrysopidae, and Hemerobiidae were collected weekly using sweep samples and sticky traps from the uncut strips and up to 40 m into the alfalfa regrowth. For 2 yr, both small- (0.34 ha) and large-scale (approximately 11.3 ha) field trials showed higher numbers of E. fabae in 73% of the uncut strips for 2-3 wk after harvest. Similarly, the number of insect predators found within <50% of the uncut strips was also higher during the first or second week after harvest. In 1999, however, we did not observe higher numbers of E. fabae in the uncut strips. Differences may be because of higher E. fabae population numbers in 1999 compared with 1998 and 2000. This research provides alfalfa growers a potential cultural management technique for E. fabae while conserving predatory insects.

Effect of serum and platelet-derived growth factor on chondrocytes grown in collagen gels.

In this in vitro study, cell proliferation, viability, and morphology; proteoglycan (PG) synthesis; and gel contraction were assessed over a 15-day period (on days 3, 6, 9, 12, and 15) for mature bovine chondrocytes cultured in collagen gels. The environment within the gel was varied by changing the concentration of fetal bovine serum (1% and 10%) and platelet-derived growth factor-BB (PDGF; 0, 10, 50, 100 ng/ml) within the gel and incubation media. Our results showed that the amount of serum or PDGF added to the gels had no effect on cell viability, with >95% of cells remaining alive throughout the experiment. There was a significant increase in cell number over time in all groups, with a higher rate of cell proliferation in gels containing 10% serum and higher concentrations of PDGF. In addition, the amount of serum significantly affected gel contraction with or without PDGF. Gels containing 10% serum contracted on day 10-12, while none of the gels containing 1% serum contracted over the course of the experiment. The PG content within each gel increased with incubation time only for the gels containing 1% serum, and 10 or 100 ng/ml of PDGF. However, on a per cell basis, there was no change in the PG content with time when only serum was used and a significant decrease in the rate of PG production with the addition of PDGF (9.1-27.8 pgPG/cell/day). Cell morphology was also affected by PDGF, with the cells becoming more spindle shaped. Cell alignment within the gels appeared to be most affected by gel contraction. Collagen gels can act as cell carriers for the purpose of tissue engineering. These gels provide a three-dimensional environment in which chondrocytes can proliferate and produce matrix. We have shown how this environment can be controlled to affect gel contraction, rates of cell growth and PG production, and cellular morphology while maintaining cell viability. This information will be useful in determining the conditions in which chondrocytes can be grown within collagen gels and combined with cytokines to create an ideal tissue construct.