Antibiotic-Resistant Spondylodiscitis With Canal Invasion and Aggressive Evolution to Epidural Abscess: A Case Series of Spontaneous Occurrence in 16 Patients.

BACKGROUND: The study aimed to assess the effectiveness of antibiotic treatment for spondylodiscitis, its failure rates, and the need for surgical intervention. METHODS: This is a retrospective study of patients who presented with spontaneous deep spinal infections and spondylodiscitis between 2011 and 2013. Clinical, bacteriologic, and radiographic data during hospitalization were analyzed. RESULTS: A total of 16 patients presented with deep spinal infections during the study period; 15 of them presented with spontaneous pyogenic spondylodiscitis, and 1 presented with epidural abscess. Median age was 68 years (range, 50-80 years), and 6 (38%) were healthy young laborers. None of the patients were immunocompromised. On admission all patients presented with pain, there was fever in 3 patients (19%), and there was elevated blood C-reactive protein, white blood cell count and erythrocyte sedimentation rate, with a mean of 147 ± 83.1 mg/L, 11.65 ± 5.6 × 103/µL, 93.6 ± 35.1 mm/h, respectively. A total of 15 patients (94%) developed infections that were refractory to appropriate culture-specific intravenous antibiotic treatment (mean, 10.2 days); 8 patients (50%) deteriorated neurologically and required wide surgical decompression. Complications included widespread epidural free gas in 2 patients (12%), multiple bilateral psoas abscesses in 2 patients (12%), kyphotic segmental instability in 4 patients (25%), and inferior vena cava septic thrombi in 1 patient (6%). A total of 3 patients (19%) died within 6 months; 7 of 13 surviving patients still had residual neurologic deficits at the 6-month follow-up. CONCLUSIONS: Spondylodiscitis may be resistant to antibiotic treatment and may evolve into epidural abscess via extension of the infection and pus into the spinal canal, necessitating repetitive surgical treatment due to neurologic and clinical deterioration, and expansion of the persistent infection with a mass effect. Increased vigilance for this condition and its misleading initial presentations is warranted.

Cervical spine injuries in civilian victims of explosions: Should cervical collars be used?

BACKGROUND: Semirigid cervical collars (SRCCs) are routinely applied to victims of explosions as part of the prehospital trauma protocols. Previous studies have shown that the use of SRCC in penetrating injuries is not justified because of the scarcity of unstable cervical spine injuries and the risk of obscuring other neck injuries. Explosion can inflict injuries by fragments penetration, blast injury, blunt force, and burns. The purpose of the study was to determine the occurrence of cervical spine instability without irreversible neurologic deficit and other potentially life-threatening nonskeletal neck injuries among victims of explosions. The potential benefits and risks of SRCC application in explosion-related injuries were evaluated. METHODS: This is a retrospective cohort study of all explosion civilian victims admitted to Israeli hospitals during the years 1998 to 2010. Data collection was based on the Israeli national trauma registry and the hospital records and included demographic, clinical, and radiologic details of all patients with documented cervical spine injuries. RESULTS: The cohort included 2,267 patients. All of them were secondary to terrorist attacks. SRCC was applied to all the patients at the scene. Nineteen patients (0.83%) had cervical spine fractures. Nine patients (0.088%) had unstable cervical spine injury. All but one had irreversible neurologic deficit on admission. A total of 151 patients (6.6%) had potentially life-threatening penetrating nonskeletal neck injuries. CONCLUSION: Unstable cervical spine injuries secondary to explosion are extremely rare. The majority of unstable cervical spine fractures were secondary to penetrating injuries, with irreversible neurologic deficits on admission. The application of SRCC did not seem to be of any benefit in these patients and might pose a risk of obscuring other neck injuries. We recommend that SRCC will not be used in the prehospital management of victims of explosions. LEVEL OF EVIDENCE: Prognostic/epidemiologic study, level III.

Extra-peritoneal pressure packing without external pelvic fixation: A life-saving stand-alone surgical treatment.

PURPOSE: Traditional maneuvers aim to decrease retroperitoneal bleeding in hemodynamically unstable multi-trauma patients with unstable pelvic fractures, are reportedly successful in approximately only 50%. The life-saving effect of extra-peritoneal pressure packing (EPPP) is based on direct compression and control of both venous and arterial retroperitoneal bleeders. This study describes the safety and efficacy of emergent EPPP employment, as a stand-alone surgical treatment, that is, carried out without external pelvic fixation or emergent angiography. MATERIALS AND METHODS: A retrospective chart review of all hemodynamic unstable, multi-trauma patients with mechanically unstable pelvic fractures treated by the EPPP technique at our medical center between the years 2005 and 2011. Survival rates, clinical, and physiological outcomes were followed prospectively. RESULTS: Twenty-five of the 181 pelvic fracture patients had biomechanically unstable fractures that required surgical fixation. Fourteen of those 25 patients had deteriorating hemodynamic instability from massive pelvic bleeding which was resistant to resuscitation, and they underwent EPPP, as a stand-alone treatment. The procedure successfully achieved hemodynamic stability in all 14 patients and obviated the early mortality associated with massive pelvic bleeding. Three of these patients eventually succumbed to their multiple injuries. CONCLUSION: Implementation of EPPP improved all measured physiological outcome parameters and survival rates of hemodynamically unstable multi-trauma patients with unstable pelvic fractures in our trauma center. It provided the unique advantage of directly compressing the life-threatening retroperitoneal bleeders by applying direct pressure and causing a tamponade effect to stanch venous and arterial pelvic blood flow and obviate the early mortality associated with massive pelvic bleeding.

Efficacy of MRI for assessment of spinal trauma: correlation with intraoperative findings.

STUDY DESIGN: Observational diagnostic study on consecutive patients. OBJECTIVE: To assess the efficacy of magnetic resonance imaging (MRI) for detecting spinal soft tissue injury after acute trauma using intraoperative findings as a reference standard. SUMMARY OF BACKGROUND DATA: Recognizing injuries to spinal soft tissue structures is critical for proper decision making and management for blunt trauma victims. Although MRI is considered the gold standard for imaging of soft tissues, its ability to identify specific components of soft tissue damage in acute spine trauma patients is poorly documented and controversial. METHODS: Intraoperative findings were recorded for 21 acute spinal trauma patients (study group) and 14 nontraumatic spinal surgery patients (control group). Preoperative MRI's were evaluated randomly and blindly by 2 neuroradiologists. MRI and intraoperative findings were compared. By using the intraoperative findings as the reference standard, sensitivity, specificity, positive and negative predictive values of MRI in detecting spinal soft tissue injury were determined. RESULTS: MRI was 100% sensitive and specific in detecting injury to the anterior longitudinal ligament. MRI was moderately sensitive (80%) but highly specific (100%) for injury to the posterior longitudinal ligament. In contrast, MRI was highly sensitive but less specific in detecting injury to paraspinal muscles (100%, 77%), intervertebral disk (100%, 71%), and interspinous ligament (100%, 64%). MRI was moderately sensitive and specific in detecting ligamentum flavum injury (80% and 86.7%) but poorly sensitive for facet capsule injury (62.5%). CONCLUSIONS: MRI demonstrated high sensitivity for spinal soft tissue injuries. However, MRI showed a definite trend to overestimate interspinous ligament, intervertebral disk, and paraspinal muscle injuries. On the basis of these results, we would consider MRI to be a useful tool for spine clearance after trauma. Conversely, caution should be applied when using MRI for operative decision making due to its less predictable specificity.

Intradural Extension of a Pyogenic Epidural Abscess: A Case Report.

CASE: Few cases of spinal epidural abscess involving an extradural abscess with an intradural extension have been reported. A unique complication with extension of pus from the epidural space through multiple perforations into the dura is described. Due to a proximal meningeal inflammatory reaction, which served as a proximal plug, no cerebrospinal fluid leak was encountered. CONCLUSION: Intradural extension of pus through multiple dural perforations is a rare complication of spinal epidural abscess and a treatment challenge. Early diagnosis enabling prompt surgical decompression, along with subsequent aggressive debridements and prolonged intravenous antibiotic treatment, can lead to a favorable outcome.

Low-back pain, lassitude and loss of appetite.

White blood cells, Erythrocyte sedimentation rate and C-reactive protein are sensitive tools to discover rare, but potentially serious pyogenic vertebral osteomyelitis, a disease whose incidence is increasing.

A cadaver study to compare vertebral augmentation with a high-viscosity cement to augmentation with conventional lower-viscosity cement.

STUDY DESIGN: Comparison of extravasations in fractured cadaver vertebrae augmented with commercial low-viscosity versus high-viscosity cements. OBJECTIVE: Use of high-resolution, 3-dimensional (3D) imaging to test the hypothesis that high-viscosity cements can reduce the type and severity of extravasations after vertebral augmentation procedures. SUMMARY OF BACKGROUND DATA: Cement extravasations are one of the primary complications of vertebral augmentation procedures. There is some evidence that high-viscosity cements might reduce extravasations, but additional data are needed to confirm the early findings. METHODS: A range of vertebral fractures were created in fresh human cadavers. One group was then augmented with a low-viscosity polymethylmethacrylate (PMMA)-based cement and the other group injected with high-viscosity PMMA-based cement. High-resolution computerized tomography exams were obtained, and extravasations were assessed using 3D volume renderings. The type and severity of extravasations were recorded and analyzed. RESULTS: The proportion of vertebrae with any type of extravasation through the posterior wall to the spinal canal, into small vessels laterally or anteriorly, through the endplates, or anywhere around the body was not significantly different between the high-viscosity and low-viscosity groups. There was significantly less severe extravasation through the endplates (P=0.02), and a trend toward less severe extravasation through vessels (P=0.06) with the high versus low-viscosity cements. CONCLUSIONS: In agreement with previous research, high-viscosity PMMA-based cement may help to reduce the more severe forms of extravasations after vertebral augmentation procedures in newly fractured vertebrae.

Toward the establishment of optimal computed tomographic parameters for the assessment of lumbar spinal fusion.

BACKGROUND CONTEXT: The accurate detection of the extent of bony fusion after attempted lumbar arthrodesis is important given that subsequent efforts-such as decisions regarding need for continued external bracing, use of enhancing modalities (electrical stimulation and pulsed ultrasound), recommended activity levels, return to employment, early surgical intervention, and others-may be needed to reduce the risk of late failure, especially in light of the fact that late revisions for failed fusions often result in poor outcomes and significant costs. Thin-cut computed tomography (CT) has emerged as the study of choice for this purpose. PURPOSE: To delineate the optimal CT parameters for determining fusion versus pseudarthosis after attempted lumbar fusion. STUDY DESIGN: Blinded CT assessment with cadaveric specimen as a gold standard. METHODS: A human cadaveric spine specimen with a T10 to S1 thoracolumbar posterolateral fusion augmented by instrumentation and anterior lumbar interbody fusions was used as a gold standard. Two experienced spine surgeons and one musculoskeletal radiologist-all blinded to the pathology results-assessed a series of CT scans of the specimen, each CT using one of six predefined sets of parameters. RESULTS: Predictive values and sensitivity generally improved with decreasing slice thickness and slice spacing, but only modestly. All sets of parameters had higher negative predictive value (NPV) than positive predictive value (PPV). Computed tomographic parameters of 0.9-mm thick sections with 50% overlap showed the highest PPV and NPV, where NPV was 90, but PPV was only 59. CONCLUSIONS: In this study, using the best widely available CT technologies and the ideal gold standard, thin-cut CT remained less than ideal for the assessment of lumbar arthrodesis/pseudarthrosis. Tuning slice thickness and slice spacing down generally improves detail, but marginally. We have successfully defined "optimal" as "best available," but "optimal" as "nearly perfect" awaits further technological advances.

Reference data for interpreting widening between spinous processes in the lumbar spine.

BACKGROUND CONTEXT: Traumatic injury to the lumbar spine is evaluated and treated based on the perceived stability of the spine. Recent classification schemes have established the importance of evaluating the posterior ligamentous complex (PLC) to fully comprehend stability. There are a variety of techniques to evaluate the PLC, including assessment of interspinous distance. However reference data to define normal widening are poorly developed. PURPOSE: Define normal interspinous widening in the lumbar spine. STUDY DESIGN: Biomechanical and observational. To establish reference data for asymptomatic population and use the reference data to suggest criteria for routine clinical practice to be validated in future studies. METHODS: Interspinous distances were measured from lateral lumbar X-rays of 157 asymptomatic volunteers. Measurements from the asymptomatic population were used to define normal limits and create a simple screening tool for clinical use. Distances were calculated from the relative position of landmarks at each intervertebral level. The distances were normalized to the anterior-posterior width of the superior end plate of L3. The change in interspinous process distance from flexion to extension was calculated, and the change in interspinous widening between flexion and extension with respect to widening at the adjacent levels was also calculated. RESULTS: Seven hundred seventy-two thoracolumbar levels were available for analysis. The observed interspinous motion was slightly more than the interlaminar motion. However, the tips of the spinous processes were more difficult to identify in some images, so the interlaminar line distances were considered more reliable. Significant difference in interlaminar distances was not found between levels. The upper limit (UL) of normal spacing measured between the interlaminar lines was approximately 85% of the L3 end plate width at all levels except L5-S1, which was 105%. The UL of normal for interlaminar displacements between flexion and extension was 30% of the L3 end plate width at L1-L2 to L4-L5 and 40% at L5-S1. CONCLUSIONS: This study provides normative data and methods that can be used in developing guidelines to objectively assess interspinous process widening. Simple rules can be applied to quickly assess interspinous widening. Additional research is required to validate these guidelines. A simple measurement such as spinous process widening is unlikely to be proven as an isolated clinically effective screening test but combining that with other patient evaluation's screening modalities may prove to be a sensitive evaluation protocol for the screening of injuries to the PLC.

Motion within the unstable cervical spine during patient maneuvering: the neck pivot-shift phenomenon.

BACKGROUND: Cervical extrication collars are applied to millions of blunt trauma victims despite the lack of any evidence that a collar can protect against secondary injuries to the cervical spine. Cadaver studies support that in the presence of a dissociative injury, substantial motion can occur within the occipitocervical spine with collar application or during patient transfers. Little is known about the biomechanics of cervical stabilization; hence, it is difficult to develop and test improved immobilization strategies. MATERIALS: Severe unstable injuries were created in seven fresh whole human cadavers. Rigid collars were applied with the body in a neutral position. Computed tomographic examinations were obtained before and after tilting the body or backboard as would be done during patient transport or to inspect the back. Relative displacements between vertebrae at the site of the injury were measured from the Computed tomographic examinations. The overall relative alignment between body and collar was assessed to understand the mechanisms that may facilitate motion at the injury site. RESULTS: Intervertebral motion averaged 7.7 mm±6.8 mm in the axial plain and 2.9 mm±2.5 mm in the cranial-caudal direction. The rigid collars appeared to create pivot points where the collar contacts the head in the region under the ear and where the collar contacts the shoulders. DISCUSSION: Rigid cervical collars appear to create pivot points that shift the center of rotation lateral to the spine and contribute to the intervertebral motions that were measured. Immobilization strategies that avoid these neck pivot-shift phenomena may help to reduce secondary injuries to the cervical spine. The whole cadaver model with simulation of patient maneuvers may provide an effective test method for cervical immobilization.

A pictorial classification atlas of cement extravasation with vertebral augmentation.

BACKGROUND CONTEXT: Minimally invasive procedures for the treatment of vertebral compression fractures (VCFs) have been in use since the mid-1980s. A mixture of liquid monomer and powder is introduced through a needle into one or both pedicles, and it polymerizes within the vertebral body in an exothermic chemical reaction. The interaction between cement and the fractured vertebral body determines whether and how the cement stabilizes the fragments, alters morphology, and extravasates. The cement is intended to remain within the vertebral body. However, some studies have reported cement leakage in more than 80% of the procedures. Although cement leakage can have no or minimal clinical consequences, adverse events, such as paraplegia, spinal cord and nerve root compression, cement pulmonary embolisms, or death, can occur. The details of how the cement infiltrates a vertebral body or extravasates out of the body are poorly understood and may help to identify strategies to reduce complications and improve clinical efficacy. PURPOSE: Apply novel techniques to demonstrate the cement spread inside vertebrae as well as the points and pattern of cement extravastation. STUDY DESIGN: Ex vivo assessment of vertebral augmentation procedures. METHODS: Vertebrae from six fresh whole human cadaver spines were used to create 24 specimens of three vertebrae each. The specimens were placed in a pneumatic testing system, designed to create controlled anterior wedge compression fractures. Unipedicular augmentation was performed on the central vertebra of 24 specimens using polymethylmethacrylate/barium sulfate Vertebroplastic cements (DePuy Spine, Raynham, MA, USA). The volume of cement injected into each vertebra was recorded. Fine-cut computed tomography (CT) scans of all segments were obtained (Brilliance 64; Philips Medical Imaging, Amsterdam, The Netherlands). Using multiplanar reconstructions and volume compositing three-dimensional imaging (Osirix, www.osirix-viewer.com), each specimen was carefully assessed for cement extravasation. Specimens were then immersed in a 50% sodium hypochlorite solution until all overlying soft tissues were removed, leaving the bone and cement intact. The specimens were dried and visually examined and photographed to assess cement extravasation and fracture patterns. Specimens were cut in the axial or sagittal plains to assess the gross morphology of cement infiltration and extravasation. Finally, 25-mm block sections were removed from selected specimens and imaged at 14-µm resolution using a GE Locus-SP micro-CT system (GE Healthcare, London, Ontario, Canada). RESULTS: Infiltration was characterized by an intimate capture of trabecular bone within the cement, forming an irregular border at the perimeter of the cement that is determined by the morphology of the trabeculae and marrow spaces. Extravasation of the cement was assessed as "any" if any small or large amount of extravastation was detected and was also assessed as severe if a large amount of extravasation was found. Out of the 23 levels studied, some extravasation was visibly apparent in all levels. A wide spectrum of filling patterns, leakage points, and interdigitation of the cement was observed and appeared to be determined by the interaction of the cement with the trabecular morphology. The results support the fact that the cement generally advances through the vertebrae with relatively regular and easily identifiable borders. CONCLUSIONS: Using a cadaver VCF model, this study demonstrated the exact filling and extravastation patterns of bone cement inside and out of fractured vertebrae. These data enhance our understanding of the vertebral augmentation and extravastation mechanics.

The association of occipitocervical dissociation and death as a result of blunt trauma.

BACKGROUND CONTEXT: Despite multiple reports of survivability, dissociative occipitocervical injury (OCI) is generally accepted to be fatal in most cases. The actual number of trauma victims where OCI may have made the difference between life and death is unknown because multiple studies have shown that these injuries can be missed with current diagnostic methods. An improved understanding of the relative importance of OCI in blunt trauma mortality may help to refine protocols for the assessment and treatment of patients who arrive alive to the emergency room after severe blunt trauma. One way to improve our understanding is to document the relative frequency OCI relative to brain, liver, aorta, and spleen injuries in blunt trauma fatalities. PURPOSE: In this study, we aimed to glean a more accurate estimate of the absolute and relative incidence of OCI after death from blunt trauma via a systematic review of data reported in the forensic literature. STUDY DESIGN: Systematic literature review. METHODS: A systematic literature search and review were undertaken. The search aimed to answer three primary questions: What is the true incidence of cervical spine injuries in blunt trauma fatalities? What is the incidence of dissociative OCIs specifically? and What is the incidence of these injuries relative to other common injuries associated with blunt trauma fatalities (central nervous system, spleen, liver, etc)? For that, two search protocols were used and included postmortem studies of blunt trauma mechanism in adult population. RESULTS: The mean reported incidence of cervical spine injuries was 49.7% in blunt trauma fatalities. Dissociative OCIs were found to have a mean incidence of 18.1%. The relative frequencies of injuries were 49.7% for cervical spine, 41.8% for central nervous system, 20.8% for liver, 11.2% for spleen, and 10.8% for aorta. CONCLUSIONS: In this systematic literature review, cervical spine injuries were found to be the most commonly reported finding associated with blunt trauma fatalities, occurring in nearly 50% of cases with occipitocervical dissociation accounting for nearly 20%. Older pathologic studies suggested a lesser overall and relative frequency and may have underestimated their incidence. Typically, these blunt cervical spine injuries were much more commonly found to disrupt the soft tissue stabilizing restraints (ligaments, facet capsules, etc) as opposed to causing bony fractures and, accordingly, were often not detected on plain radiographs. It is likely that the frequency of this injury is underestimated in patients surviving severe blunt trauma, placing them at risk for death from an occult source in the postinjury period. Additional research is needed to determine if improved methods to diagnose OCI and improved patient management protocols to protect against secondary injuries might reduce mortality in blunt trauma victims.

Occipitocervical dissociative injuries: common in blunt trauma fatalities and better detected with objective computed tomography-based measurements.

BACKGROUND CONTEXT: Occipitocervical injuries (OCIs) are generally not common in blunt trauma victims, but autopsy studies of blunt trauma fatalities consistently report a high prevalence of these injuries. New computed tomography (CT)-based quantitative criteria have recently been developed for use in assessing the occipitocervical spine. The efficacy of these new criteria for detecting OCI would be supported if the high prevalence of OCI in blunt trauma fatalities can also be detected using these objective CT-based criteria. PURPOSE: To test the hypothesis that the prevalence of OCI in blunt trauma fatalities, determined using objective CT-based measurements and reliable reference data, will be similar to the prevalence reported in prior autopsy studies. STUDY DESIGN/SETTING: Retrospective assessment of the CT examinations of blunt trauma fatalities at a Level 1 trauma center. PATIENT SAMPLE: Seventy-four consecutive patients who died within 21 days of blunt trauma and had a CT examination of the cervical spine. OUTCOME MEASURES: Quantitative measurements from CT examinations of the occiput-C1 and C1-C2 levels. METHODS: Measurements were made on a Picture Archiving and Communication System (PACS) from the CT images that were originally used for diagnosis and also using imaging software that allowed for precisely reoriented slices that correct for variations in the alignment of the upper cervical spine. The prevalence of abnormal measurements found by each method and the interobserver reliability of the measurements were assessed. RESULTS: At least one abnormal measurement was found in 50% of cases based on measurements made on the PACS, and in 34% of cases using measurements from carefully reoriented images. At least three abnormal measurements were found in 22% and 14% of patients, respectively. Only one of the patients had been diagnosed as having an OCI before death. Interobserver reliability measurements of more than 80% were found for most measurements. CONCLUSIONS: Using precise CT-based measurements and reliable reference data for diagnosis of occipitocervical dissociative injuries, the prevalence of injuries in severely injured blunt trauma patients was close to the levels reported in prior autopsy studies (approximately 30%). This supports that with careful measurements, both soft- and hard-tissue OCI can be detected by CT. This study is limited by the fact that a gold standard was not available to confirm the injuries.

Comprehensive computed tomography assessment of the upper cervical anatomy: what is normal?

BACKGROUND CONTEXT: High-speed computed tomography (CT) exams have replaced traditional radiographs for assessment of cervical spine injuries in many emergency departments. Recent evidence demonstrates that even subtle displacements can indicate significant upper cervical spine injuries. Many different anatomical measurements have been described in the upper cervical spine to date, most of them based on X-ray. The range of anatomical relationships that exist in an uninjured population must be known to reliably detect abnormal relations. The measurements with the lowest normal variation are likely to be most useful in detecting injuries. PURPOSE: The purpose of this study was to describe the normal quantitative anatomical relationships as well as the threshold measurements most likely to detect injury in the upper cervical spine. STUDY DESIGN/SETTING: Retrospective anatomical case review. PATIENT SAMPLE: Seventy-six thin-sliced cervical CT scans randomly selected from a trauma population, all negative for injury in the cervical spine. METHODS: Forty-two different anatomical measurements were made of the upper cervical spine. These included traditional historical measurements and other detailed dimensions to characterize occipitocervical (OC) and atlantoaxial (AA) joint relationships. RESULTS: After review of all the anatomical measurements performed in the upper cervical spine, direct measurements of the joint space had the least variation. The mean OC joint space was 0.6mm, with an upper 95% confidence interval (CI) of 1mm at the most anterior or posterior aspects of the joints. This was true for both sagittal and coronal measurements. The mean AA joint space was 0.6mm, with an upper 95% CI of 1.2mm at the lateral aspect of the joint on the coronal image only. The midsagittal structures demonstrated significantly higher standard deviation and variability. CONCLUSIONS: These results revealed consistently narrow joint spaces and left-right symmetry in the upper cervical spine joints that do not vary according to demographics. There was distinctly greater consistency in the coronal plane, which enabled more precise diagnostic measurement and side-to-side comparison of measurements. This precision will enable more accurate identification of abnormal scans, which should prompt consideration for additional workup. Thus, better understanding of these relationships may enable earlier detection of subtle craniocervical dissociative injuries based on CT scan data. This is important, because the only evidence of a severe injury on CT can be subtle misalignment.

Reference data for assessing widening between spinous processes in the cervical spine and the responsiveness of these measures to detecting abnormalities.

BACKGROUND CONTEXT: Traumatic injury to the spine is evaluated and treated based on the perceived stability of the spine. Recent classification schemes have established the importance of evaluating the discoligamentous complex to fully comprehend stability. There are a variety of techniques to evaluate the discoligamentous complex, including assessment of interspinous distance. However, there currently are no clinically validated methods to define and assess abnormal interspinous widening. PURPOSE: The purpose of the study was to provide reference data and evidence to support the objective use of spinous process widening in the diagnosis of cervical spine injury and instability. STUDY DESIGN: The study was designed to be biomechanical and observational. METHODS: Distances between spinous processes were measured from lateral flexion-extension X-rays of 156 skeletally mature asymptomatic subjects who reported never having had neck symptoms as well as 12 whole human cadavers before and after creating increasingly severe damage to posterior structures. Cervical interspinous distances were measured and then normalized to the width of the C4 vertebral end plate. The change in the distance from flexion to extension was also calculated. RESULTS: Descriptive statistics, including the 95% confidence intervals for each cervical level were tabulated for 863 levels in 149 analyzable asymptomatic volunteers. In the simulated cadaver model, interspinous widening was highly specific and mildly sensitive for detecting damage to the posterior structures of the cervical spine. CONCLUSIONS: This study provides reference data that can be used to quantitatively assess interspinous process widening in the cervical spine. Application of the reference data to a cadaver model of cervical trauma suggests that although objective evidence of abnormal widening may be uncommon, when present, it is suggestive of extensive damage to the cervical spine. Derived from this data were two "rule of thumb" criteria to identify abnormal interspinous widening in flexion X-rays; when greater than 30% relative to an adjacent level (40% between C1-C2 and C2-C3) or greater than 50% of the anterior-posterior width of the C4 vertebral body (30% for C2-C3).

Diagnosis of unstable cervical spine injuries: laboratory support for the use of axial traction to diagnose cervical spine instability.

BACKGROUND: The ability to detect damage to the intervertebral structures is critical in the management of patients after blunt trauma. A practical and inexpensive method to identify severe structural damage not clearly seen on computed tomography would be of benefit. The objective of this study was to assess whether ligamentous injury in the subaxial cervical spine can be reliably detected by analysis of lateral radiographs taken with and without axial traction. METHODS: Twelve fresh, whole, postrigor-mortis cadavers were used for this study. Lateral cervical spine radiographs were obtained during the application of 0 N, 89 N, and 178 N of axial traction applied to the head. Progressive incremental sectioning of posterior structures was then performed at C4-C5 with traction imaging repeated after each intervention. Intervertebral distraction was analyzed using computer-assisted software. RESULTS: Almost imperceptible intervertebral separation was found when traction was applied to intact spines. In the subaxial cervical spine, the average posterior disc height consistently increased under traction in severely injured spines. The average disc height increase was 14% of the C4 upper endplate width, compared with an average of 2% in the noninjured spines. A change of more than 5% in posterior disc height under traction was above the 95% confidence interval for intact spines, with sensitivity of 83% and specificity of 80%. Applied force of 89 N (20 lb) was sufficient to demonstrate injury. The combination of assessing alignment and distraction under traction increased both the sensitivity and specificity to nearly 100%. CONCLUSION: This study supports further clinical investigations to determine whether low-level axial traction may be a useful adjunct for detecting unstable subaxial cervical spine injuries in an acute setting.

Extrication collars can result in abnormal separation between vertebrae in the presence of a dissociative injury.

BACKGROUND: Cervical collars are applied to millions of trauma victims with the intent of protecting against secondary spine injuries. Adverse clinical outcomes during the management of trauma patients led to the hypothesis that extrication collars may be harmful in some cases. The literature provides indirect support for this observation. The purpose of this study was to directly evaluate cervical biomechanics after application of a cervical collar in the presence of severe neck injury. METHODS: Cranial-caudal displacements in the upper cervical spine were measured in cadavers from images taken before and after application of collars following creation of an unstable upper cervical spine injury. RESULTS: In the presence of severe injury, collar application resulted in 7.3 mm +/- 4.0 mm of separation between C1 and C2 in a cadaver model. In general, collars had the effect of pushing the head away from the shoulders. CONCLUSIONS: This study was consistent with previous evidence that extrication collars can result in abnormal distraction within the upper cervical spine in the presence of a severe injury. These observations support the need to prioritize additional research to better understand the risks and benefits of cervical stabilization methods and to determine whether improved stabilization methods can help to avoid potentially harmful displacements between vertebrae.

An evidence-based clinical guideline for the use of antithrombotic therapies in spine surgery.

BACKGROUND CONTEXT: The objective of the North American Spine Society (NASS) Evidence-Based Clinical Guideline on antithrombotic therapies in spine surgery was to provide evidence-based recommendations to address key clinical questions surrounding the use of antithrombotic therapies in spine surgery. The guideline is intended to address these questions based on the highest quality clinical literature available on this subject as of February 2008. The goal of the guideline recommendations was to assist in delivering optimum, efficacious treatment with the goal of preventing thromboembolic events. PURPOSE: To provide an evidence-based, educational tool to assist spine surgeons in minimizing the risk of deep venous thrombosis (DVT) and pulmonary embolism (PE). STUDY DESIGN: Systematic review and evidence-based clinical guideline. METHODS: This report is from the Antithrombotic Therapies Work Group of the NASS Evidence-Based Guideline Development Committee. The work group was composed of multidisciplinary spine care specialists, all of whom were trained in the principles of evidence-based analysis. Each member of the group was involved in formatting a series of clinical questions to be addressed by the group. The final questions agreed on by the group are the subject of this report. A literature search addressing each question and using a specific search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology), and four additional, evidence-based databases. The relevant literature was then independently rated by at least three reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final grades of recommendation for the answers to each clinical question were arrived at via Web casts among members of the work group using standardized grades of recommendation. When Level I to IV evidence was insufficient to support a recommendation to answer a specific clinical question, expert consensus was arrived at by the work group through the modified nominal group technique and is clearly identified as such in the guideline. RESULTS: Fourteen clinical questions were formulated, addressing issues of incidence of DVT and PE in spine surgery and recommendations regarding utilization of mechanical prophylaxis and chemoprophylaxis in spine surgery. The answers to these 14 clinical questions are summarized in this article. The respective recommendations were graded by the strength of the supporting literature that was stratified by levels of evidence. CONCLUSIONS: A clinical guideline addressing the use of antithrombotic therapies in spine surgery has been created using the techniques of evidence-based medicine and using the best available evidence as a tool to assist spine surgeons in minimizing the risk of DVT and PE. The entire guideline document, including the evidentiary tables, suggestions for future research, and all references, is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.

Infectious Collet-Sicard syndrome in the differential diagnosis of cerebrovascular accident: a case of head-to-neck dissociation with skull-based osteomyelitis.

BACKGROUND CONTEXT: Collet-Sicard syndrome (CSS) is a rare condition that includes palsies of cranial nerves IX, X, XI, and XII. There are multiple reported causes in the literature, although infection is particularly unusual. PURPOSE: To report an unusual case of CSS as a result of infection causing head-to-neck dissociation with involvement of the upper cervical spine. STUDY DESIGN: Case report. METHODS: A 56-year-old male with medical comorbidities developed a cranial-based infection secondary to initial incomplete treatment of otitis media. The mass effect of the infection resulted in multiple cranial nerve palsies and extremity symptoms initially confused with a cerebrovascular accident. Clinical course of the patient and a review of CSS are presented. RESULTS: With progression of the disease, further evaluation revealed a disseminated upper cervical and skull-based infection causing destructive head-to-neck infectious instability. This was treated with posterior occipitocervical debridement, fixation, and fusion and appropriate long-term antibiotics. Over the course of several months, the infection resolved and there was a significant improvement in his dysphagia, dysarthria, and hearing. CONCLUSIONS: Delay in diagnosis of CSS is common, and this syndrome should be considered in patients who present with a constellation of lower cranial nerve palsies. Early recognition and treatment should result in successful recovery, but even in cases of delayed detection, suitable intervention can result in substantial clinical improvement.

Internal decapitation: survival after head to neck dissociation injuries.

STUDY DESIGN: Case series. OBJECTIVE: To describe survival and outcomes after occipitocervical dissociation injuries. SUMMARY OF BACKGROUND DATA: Historically, occipitocervical dissociation injuries have a high rate of associated neurologic deficit with a relatively high incidence of mortality. METHODS: Six patients with occipitocervical dissociation injuries are reported and their management and imaging findings reviewed. Possible contributory factors for survival are discussed. RESULTS: All patients had upper neck and head dissociation injuries. The pattern of injury in all of these cases included a distraction type mechanism. All cases demonstrated soft tissue disruption in the zone of injury, which was consistent and apparent on all imaging studies. In these patients, the extent and severity of injury was more apparent on magnetic resonance imaging (MRI) than on radiograph or computed tomography scan. Management of these injuries included immobilization followed by surgery with particular care taken to avoid application of distraction forces to the neck. CONCLUSION: Patients with occipitocervical dissociation injuries may survive their injury and even retain neurologic integrity. Initial in-line head stabilization is emphasized to prevent catastrophic neurologic injury. The resting osseous relationships and vertebral alignment at the time of imaging evaluation may be deceivingly normal, and the damage often primarily or exclusively involves disruption of the perivertebral soft tissue structures. Prevertebral soft tissue swelling was apparent in all cases. For these injuries that involve primarily damage to the ligamentous structures, MRI seems to be the optimal test for revealing the magnitude of the injury.