Transosseous flexion-distraction injuries of the spine typically require surgical intervention by stabilizing the fractured vertebra during healing with a pedicle-screw-rod constructs. As healing is taking place the load shifts from the implant back to the spine. Monitoring the load-induced deflection of the rods over time would allow quantifiable postoperative assessment of healing progress without the need for radiation exposure or frequent hospital visits. This approach, previously demonstrated to be effective in assessing fracture healing in long bones and monitoring posterolateral spinal fusion in sheep, is now being investigated for its potential in evaluating lumbar vertebra transosseous fracture healing. Six human cadaveric spines were instrumented with pedicle-screws and rods spanning L3 vertebra. The spine was loaded in Flexion-Extension (FE), Lateral-Bending (LB) and Axial-Rotation (AR) with an intact L3 vertebra (representing a healed vertebra) and after transosseous disruption, creating an AO type B1 fracture. The implant load on the rod was measured using an implantable strain sensor (Monitor) on one rod and on the contralateral rod by a strain gauge to validate the Monitor's measurements. In parallel the range of motion (ROM) was assessed.Introduction
Method
In daily clinical practice, progression of spinal fusion is typically monitored during clinical follow-up using conventional radiography and Computed Tomography scans. However, recent research has demonstrated the potential of implant load monitoring to assess posterolateral spinal fusion in an in-vivo sheep model. The question arises to whether such a strain sensing system could be used to monitor bone fusion following lumbar interbody fusion surgery, where the intervertebral space is supported by a cage. Therefore, the aim of this study was to test human cadaveric lumbar spines in two states: after a transforaminal lumbar interbody fusion (TLIF) procedure combined with a pedicle-screw-rod-construct (PSR) and subsequently after simulating bone fusion. The study hypothesized that the load on the posterior instrumentation decreases as the segment stiffens due to simulated fusion. A TLIF procedure with PSR was performed on eight human cadaveric spines at level L4-L5. Strain sensors were attached bilaterally to the rods to derive implant load changes during unconstrained flexion-extension (FE), lateral bending (LB) and axial rotation (AR) loads up to ±7.5Nm. The specimens were retested after simulating bone fusion between vertebrae L4-L5. In addition, the range of motion (ROM) was measured during each loading mode.Introduction
Method
Intervertebral disc (IVD) degeneration is a prominent cause of low back pain. IVD cells expressing angiopoietin-1 receptor Tie2 represent a progenitor cell population which decreases with progression of IVD degeneration. Homing of mesenchymal stem cells (MSCs) is a physiological mechanism aiming to enhance the regenerative capacity of the IVD. The purpose of this study was to assess the effect of MSC homing on the Tie2 positive IVD progenitor cell population, the IVD cell viability, and the proliferative phenotype of the IVD cells. Human MSCs were isolated from bone marrow aspirates and labelled with fluorescent dye. Whole IVDs with endplates were harvested from bovine tails; MSCs were placed on the endplates. Human traumatic, degenerative and healthy IVD tissues were obtained from patients and organ donors. MSCs were added onto tissue samples. After 5 days, IVD cells were isolated. Percentages of Tie2 positive, DAPI positive (dead) and Ki-67 positive (proliferative) IVD cells were determined. MSC homing or co-culture significantly increased the proportion of Tie2 positive progenitor IVD cells in bovine and 7/10 human IVDs, decreased the fraction of dead IVD cells in bovine and 7/10 human IVDs, and induced a proliferative phenotype in bovine and 5/6 human IVDs.Background and Purpose
Methods and Results
Carriers for local delivery of stem cells into degenerative intervertebral discs need to be tested under physiological loading since stem cell viability, density and differentiation, as well as carrier stability are strongly affected by loading. The success of the local delivery of mesenchymal stem cells (MSCs) to degenerative discs relies on three main factors: (i) an appropriate delivery method, (ii) a suitable carrier, (iii) resistance to loading forces. Bioreactors allow the application of loading to whole intervertebral discs and represent a useful tool to screen the potential of new regenerative therapies. We have previously shown that hydrogel delivery through the endplate (EP) leaves the annulus fibrosus (AF) intact (as opposed to an approach through the AF). Furthermore, we have found that the physiological loading needs to be adapted for nucleotomised discs. In this study we compare the behaviour of two MSCs carriers under loading in a whole IVD bioreactor.Summary
Introduction
Significant access morbidity with intercostal neuralgia and post-thoracotomy pain syndrome was reported in case that an anterior approach for spondylodesis of fractures of the thoracolumbar spine was used. We describe our experience with thoracoscopical fusion from anterior as a less invasive approach. Between 02/2007 and 09/2008 in a series of 32 patients (18 male; mean age 43, 17–74yrs) with fractures of the thoracolumbar spine (level Th11: n = 2, level Th12: n = 12, level L1: n = 18; fracture types: A3.1.1: n = 15, A3.2.1: n = 11, A3.3.1: n = 3, B2.1: n = 1 and B2.3: n = 2) thoracoscopical fracture stabilization was performed. A less invasive approach with three portals without an assistant was used facilitated by a new retractor system. In 16 patients fracture stabilization from anterior was supported by an additional spondylodesis using an dorsal approach. For reconstruction of the anterior column a VLIFT-system (n = 19), a Synex- (n = 11) or a Harms-Cage (n = 2) in combination with a MACS-TL (n = 16) or a Arcofix-system (n = 2) were used.Introduction
Patients
Pelvic x-ray is a routine part of the primary survey of Advanced Trauma Life Support (ATLS) guidelines. However, pelvic CT is the gold standard in the diagnosis of pelvic fractures. This study aims to confirm the safety of a modified ATLS algorithm omitting pelvic x-ray in hemodynamically stable polytraumatized patients with clinically stable pelvis, in favour of later pelvic CT scan. A retrospective analysis of polytraumatized patients in our emergency room was conducted between 2005 and 2006. Inclusion criteria were blunt abdominal trauma, initial hemodynamic stability and clinically stable pelvis. We excluded patients requiring immediate intervention. We reviewed the records of 452 patients. 91 fulfilled inclusion criteria (56% male, mean age 45 years). 43% were road traffic accidents and 47% falls. In 68/91 (75%) patients, both pelvic x-ray and CT examination were performed; the remainder had only pelvic CT. In 6/68 (9%) patients, pelvic fracture was diagnosed by pelvic x-ray. None false positive pelvic x-ray was detected. In 3/68 (4%) cases a fracture was missed in the pelvic x-ray, but confirmed on CT. 5 (56%) were classified type A fractures, and another 4 (44%) B 2.1 in computed tomography (AO classification). One A 2.1 fracture was found in a clinically stable patient who only received CT scan (1/23). In hemodynamically stable patients with clinically stable pelvis, x-ray sensitivity is only 67% and it may safely be omitted in favor of a pelvic CT examination. The results support the safety and utility of our modified ATLS algorithm
