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Background: Sacral U‑shaped fractures are rare but severe injuries. Due to the resulting spinopelvic dissociation they are highly unstable. Reduction and stabilization are usually required and decompression may be necessary due to frequent concomitant neurological injuries. In the literature there is no consensus with respect to the selection of the surgical approach., Case Presentations: After a road traffic accident an 18-year-old woman suffered a U-fracture of the sacrum type II according to Roy-Camille and was treated with bilateral double sacroiliac screw osteosynthesis and sacral laminectomy. A 76-year-old man with a U‑fracture type I according to Roy-Camille after falling down the stairs was treated by lumbopelvic fixation. A 24-year-old man with U‑fracture type II according to Roy Camille after a road accident was treated with triangular vertebropelvic stabilization and sacral laminectomy. For all patients the outcome was good., Conclusion: Surgical treatment is necessary, with minimally invasive techniques offering advantages over open surgery. A distinction must be made between lumbopelvic fixation and posterior pelvic ring fixation. Multiple aspects must be taken into consideration of the indications when selecting the surgical technique.

Background: Although minimally invasive posterior spine implant systems have been introduced, clinical studies reported on reduced quality of spinal column realignment due to correction loss. The aim of this study was to compare biomechanically two minimally invasive spine stabilization systems versus the Universal Spine Stabilization system (USS)., Methods: Three groups with 5 specimens each and 2 foam bars per specimen were instrumented with USS (Group 1) or a minimally invasive posterior spine stabilization system with either polyaxial (Group 2) or monoaxial (Group 3) screws. Mechanical testing was performed under quasi-static ramp loading in axial compression and torsion, followed by destructive cyclic loading run under axial compression at constant amplitude and then with progressively increasing amplitude until construct failure. Bending construct stiffness, torsional stiffness and cycles to failure were investigated., Results: Initial bending stiffness was highest in Group 3, followed by Group 2 and Group 1, without any significant differences between the groups. A significant increase in bending stiffness after 20'000 cycles was observed in Group 1 (p = 0.002) and Group 2 (p = 0.001), but not in Group 3, though the secondary bending stiffness showed no significant differences between the groups. Initial and secondary torsional stiffness was highest in Group 1, followed by Group 3 and Group 2, with significant differences between all groups (p ≤ 0.047). A significant increase in initial torsional stiffness after 20'000 cycles was observed in Group 2 (p = 0.017) and 3 (p = 0.013), but not in Group 1. The highest number of cycles to failure was detected in Group 1, followed by Group 3 and Group 2. This parameter was significantly different between Group 1 and Group 2 (p = 0.001), between Group 2 and Group 3 (p = 0.002), but not between Group 1 and Group 3., Conclusions: These findings quantify the correction loss for minimally invasive spine implant systems and imply that unstable spine fractures might benefit from stabilization with conventional implants like the USS.

Background: A common method to restore the sagittal alignment and stabilize the spinal column is a dorso-ventral spondylodesis. It is assumed that correction loss after posttraumatic spondylodesis results from inadequate incorporation of the autologous iliac crest graft., Materials and Methods: Retrospective documentation of patients with unstable vertebral body fractures of the thoracic or lumbar spine with concomitant rupture of at least one adjacent intervertebral disk who received surgical treatment at our institution from 2000 to 2006. Followed by analysis of the computer tomography documentation of a total of 142 patients with unstable vertebral body fracture stabilized by posterior internal fixator and anterior iliac crest spondylodesis., Results: The following mean angle changes were derived from the second series of CT scans performed on average 283 days after anterior spondylodesis: vertebral wedge angle (VWA): 2.1°; segmental kyphotic angle: 4.9°; adjusted-SKA: 4.8°; sagittal index (SI): -0.04; segmental-scoliotic-angle (SSA): 0°; adjusted-SSA: 0°. Changes in VWA, both SKAs and SI postoperatively and prior to ME, were statistically significant (P<0.05). The McAfee fusion assessment of the graft showed: full fusion: cranial 64%, caudal 47%; partial fusion: cranial 20.5%, caudal 29%; lysis: cranial 8.5%, caudal 17%; graft resorption: 7%. No correlation was found between the above-mentioned angle changes and fusions grade., Discussion: The importance of radiological evidence of fusion deficiency is questionable, because the extent of fusion only has a minimal effect on correction loss., Level of Evidence: Level IV., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Background: The objective of this study was the radiological evaluation of osseous integration of autologous iliac crest graft and bovine bone graft after spondylodesis based on a standardized score., Material and Methods: Spondylodesis was performed on 18 sheep, divided into 2 groups, 1 with an autologous iliac crest graft and the other with a bovine bone graft. Computed tomography was performed 12 and 24 weeks postoperatively. The osseous integration was assessed by the Tübinger Score., Results: The evaluation of the CT scans demonstrated a significantly better osseous integration of the autologous iliac crest graft compared to the bovine bone graft., Conclusions: Based on our results, the bovine bone graft as a transplant for spondylodesis is inadvisable.

Study Design: Retrospective clinical study in patients with dorso-ventral thoraco-lumbar spondylodesis., Objective: To investigate whether the ratio between graft cross sectional area and the surface area of the adjacent endplates has any effect on the midterm stability of the spondylodesis. Dorso-ventral spondylodesis in the region of the thoraco-lumbar spine is one of the most frequent operations in orthopaedic surgery. Anterior stabilization with autologous iliac crest graft currently is a standard approach in many hospitals. Although numerous recommendations are given how to perform this technique, no clinical advice is available with regard to minimum graft size., Methods: Sixty-four-slice CT-scans were obtained from 82 patients 4-12 months after posterior spondylodesis with anterior implantation of iliac crest graft and stabilization with an internal fixator. The scans were analyzed using image analysis software. First, the cross sectional area of the graft was calculated and then the surface area of the adjacent endplates. The ratio between graft cross sectional area and endplate surface area was then calculated from these two values. The grafts were then evaluated in sagittal reconstruction for signs of fracture., Results: The probability for graft fracture in autologous tricortical grafts was >0.1% (p < 0.001) if the graft cross sectional area exceeded 23.9% of the surface area of the adjacent endplates. Patients with lower ratio values had a higher fracture risk and below a value of 10% all grafts fractured., Conclusion: The relationship between graft cross sectional area and adjacent endplate area has an important effect on graft midterm stability in ventral spondylodesis of the thoraco-lumbar spine. In our opinion, the risk of graft fractures in dorso-ventral spondylodesis can be reduced by implantation of an appropriately sized graft without any additional procedures or instrumentation.

Study Design: Sheep anterior spinal fusion model with autogenous and xenogenous bone grafts., Objective: To investigate whether the relationship between cross-sectional area of the bone graft and area of the adjacent vertebral endplates has an effect on graft fracture rate., Summary of Background Data: Anterior spondylodesis with autogenous iliac crest transplant is a frequently performed operation to stabilize spinal motion segments but to date no precise recommendations with respect to minimum graft size are available in the literature., Methods: Anterior spondylodesis using autogenous and xenogenous grafts of constant size in combination with an angular stable plate (Macs TL). Autogenous iliac crest graft was inserted in eight sheep and xenogenic, commercially available bovine graft (Tutobone) in the additional eight animals. The surface areas of the endplates of the fused intervertebral space were calculated using CT scans and contact radiographs of the specimens obtained after 24 weeks. The graft itself was evaluated for fractures and osteolysis., Results: A fracture occurred in tricortical, autogenous grafts if the graft cross-sectional area was less than 21% of the area of the adjacent endplates. All xenogenic grafts fractured and therefore a comparable value could not be determined., Conclusion: The results clearly indicate that the relation between graft cross-sectional area and endplate area defines the survival or fracture of the graft in anterior spinal fusion. Although it is difficult to directly apply the results to the clinical situation it is suggested to choose a sufficiently large graft, in order to reduce the risk of autogenous graft fracture in anterior spondylodesis., (2009 Elsevier Ltd. All rights reserved.)

Background: The complication rate after trauma-associated spine surgery remains unknown because of the rarity of this injury and the polymorphism of treatment methods. We report the complication rates recorded at one center after treatment of unstable vertebral body fractures according to a single, uniform procedure. The aim of this analysis was to identify the typical complications associated with this surgical procedure and, consequently, to contribute to critical deliberations on the introduction of technical innovations such as navigation, intraoperative three-dimensional imaging, and neuromonitoring., Methods: Perioperative complications related to surgery of 208 consecutive patients, operated on for unstable vertebral body fractures were analyzed. First, stabilization was performed through an open, posterior, nonnavigated approach. This was followed, in all patients, by reconstruction of the anterior column form with a tricortical iliac crest graft during a second operation., Results: In regard to posterior stabilization, at least one pedicle screw in six patients (3%) was placed incorrectly; furthermore, there were five patients with general complications, all of which required revision surgery. After anterior spondylodesis, there were also nine general complications and five neurological complications, one of them in a patient with persistent paraplegia. At the graft donor site, three patients experienced an avulsion fracture of the anterosuperior iliac crest. Overall, at least one complication occurred in 13% of patients (confidence interval 0.08-0.18)., Conclusions: With regard to early complications, two-stage anteroposterior stabilization of unstable spinal fractures of the thoracolumbar spine is a reliable procedure.

Patients suffering form epilepsy have an increased risk for fractures. Beside fractures caused by fall or accident muscles forces alone generated during tonic-clonic seizure can result in severe musculoskeletal injury. Contractions of strong paraspinal muscles can lead to compression fracture of the mid-thoracic spine. We report a patient who had suffered from a tonic-clonic seizure during early morning hours. After a cracking sound the patient woke up in a state of post-ictal disorientation, loss of urine and tongue bite. He was admitted to our facilities with the suspected vertebral fracture albeit he just reported of mild lower back pain. Native X-rays and computer-tomography scans showed instable burst fractures of L2 and L4. The fractures were stabilised with a dorsally instrumented internal fixator from L1 to L5 followed by hemi-laminectomy and ventral spondylodesis. Muscle force alone can result in severe skeletal trauma including vertebral fractures. This example emphasizes the importance of critical examination of patients after grand mal seizures. Seizures-induced injuries can appear clinically asymptomatic and can easily be overseen due to absence of trauma and post-ictal impairment of consciousness.

Over the period between 06/00 and 03/03, 41 patients with different injuries of the upper cervical spine were treated by a halo fixator and were statistically recorded. The collective showed different injury patterns, 2 fractures of occiput condyles (5%), 3 Jefferson fractures (7%), 1 combined injury of the odontoid process and an atlas fracture (2%), 32 odontoid fractures (78%), 2 hanged-man-fractures Typ Effendi II (5%) and one case of pathologic fractures from the 2. to the 4. cervical vertebral body based on a plasmocytoma (2%). 31 of 41 patients could be examined for a follow up; 40 complete medical histories were well documented and could be analysed. As complications we had screw loosening in 6 cases (15%), a complete tear out of screws in 2 cases (5%). One patient took the halo away by himself two times, so after the second time surgical stabilisation was performed (2,5%). One case of intracranial penetration of a screw happened after the patient fell down in an accident with the halo (2,5%). Infection of the screw pins appeared in 4 cases (10%) and we had 2 cases of skin necrosis (5%). A second reduction after redisplacement was necessary in 8 cases (20%). 23 patients suffered from pain at the insertion of the screws (75%) and 18 patients complained of pressure in the head (58%). On the question of the comfort of this kind of therapy answered 18 patients with "intolerable" (58%), 10 patients with middle (32%) and 3 patients with tolerable (10%). Despite of the large number of different complications and the miscomfort of a halo fixator we think that there are still indications for treatment of special injuries of the upper cervical spine with a halo fixator. One important aspect is the lack of adequate alternatives even with regard to the biomechanical stability.

The incidence of diffuse idiopathic sceletal hyperostosis (DISH) is described in men more than 50 years old up to 25% and in women up to 15%. Even little trauma in patients with DISH often leads to injuries of the spine, especially the cervical spine. In many cases MRI is necessary to find the injury in this anatomically modified spine. It is often difficult to detect the injury by plane radiographs or even CT. Based on two cases of cervical spine fractures in patients with DISH we will describe the difficulties and specialities in the diagnostics and surgical treatment of injuries of the cervical spine in patients with DISH. In the one case we stabilized a patient with an odontoid fracture type Andersson II, the other case was a traumatic spondylolisthesis C4/C5. Both cases were treated operatively, the odontoid fracture was stabilized by a single screw, the spodylolisthesis by a ventral plate. If there are modifications in the spinal anatomy by degenerative diseases like DISH or spondylitis ankylosans, it is important to perform an intense search for injuries of the spine. In many cases MRI is indicated to detect the injury because plane radiographs and CT are not sensitive enough. For the planning of the operation it is important to meet concerns to the thick anterior longitudinal ligament and to use screws, that are long enough because the use of standard instruments is often not successful.

Purpose of the Study: In the period from 06/00 to 08/02, 31 patients with odontoid fractures type Anderson II and III were treated and stastically recorded. 25 patients were followed up; the progess of 24, documented in detail radiographically, were evaluated independently by a traumatologist and by a radiologist. The usual time of immobilization when treating odontoid fractures type Anderson type II and III with the halo-fixator is 12 weeks. For this 12 weeks that it is worn, objective assessment of bone healing is performed radiographically and the results critically considered in terms of the length of time that the halo-fixator should be worn and whether this duration should be altered on the basis of the clinical and radiological results obtained., Materials and Methods: 16 patients with an odontoid fracture type Anderson type II were treated partly with a halo-fixator and partly by additional operative stabilization. 15 patients with a type III fracture were treated in a halo over 12 weeks. At the time of the accident the patients to be treated had to have conventional radiographic examination and a CT scan as well as a position check following reduction. After 4, 8 and 12 weeks radiographic and CT investigation was repeated. These findings were evaluated independently by a surgeon and a radiologist. The clinical follow-up was carried out using the VAS Score and, in addition, the general activity level before and after the accident was recorded in a similar way on the Tegner/Lysholm subjective activity score., Results: In most cases, according to the CT scan, the osseous bridging decreased again between the 8th and 12th weeks, as defined by resorption zones seen during the fracture healing period. Radiological evidence of complete osseous bridging was only seen after 12 weeks in three cases., Conclusion: Conventional radiography does not seem to us to be the most suitable technical means to evaluate osseous healing in odontoid fractures. The CT is more reliable for this. According to our radiological results, osseous healing of different types of odontoid fractures takes more than 12 weeks. Despite of its known complications, the halo fixator is still a good instrument for the treatment of odontoid fractures.

We describe a case of the rare entity of a persistent ossicle on the top of the odontoid process. In a short review of the literature, we show developmental abnormalities of the odontoid process and its etiologies. The terminal ossicle (Bergmann) plays an important role in the differential diagnosis of a fracture of the odontoid process type I in adults using the classification of Anderson and D'Alonzo. If fracture and instability is excluded by plain radiographs, computed tomography and/or MRI, there is no need for additional therapy.