A.J.F. Hosman

A clinical prediction rule for ambulation outcomes after traumatic spinal cord injury: a longitudinal cohort study

BACKGROUND Traumatic spinal cord injury is a serious disorder in which early prediction of ambulation is important to counsel patients and to plan rehabilitation. We developed a reliable, validated prediction rule to assess a patients chances of walking independently after such injury. METHODS We undertook a longitudinal cohort study of adult patients with traumatic spinal cord injury, with early (within the first 15 days after injury) and late (1-year follow-up) clinical examinations, who were admitted to one of 19 European centres between July, 2001, and June, 2008. A clinical prediction rule based on age and neurological variables was derived from the international standards for neurological classification of spinal cord injury with a multivariate logistic regression model. Primary outcome measure 1 year after injury was independent indoor walking based on the Spinal Cord Independence Measure. Model performances were quantified with respect to discrimination (area under receiver-operating-characteristics curve [AUC]). Temporal validation was done in a second group of patients from July, 2008, to December, 2009. FINDINGS Of 1442 patients with spinal cord injury, 492 had available outcome measures. A combination of age (<65 vs ≥65 years), motor scores of the quadriceps femoris (L3), gastrocsoleus (S1) muscles, and light touch sensation of dermatomes L3 and S1 showed excellent discrimination in distinguishing independent walkers from dependent walkers and non-walkers (AUC 0·956, 95% CI 0·936-0·976, p<0·0001). Temporal validation in 99 patients confirmed excellent discriminating ability of the prediction rule (AUC 0·967, 0·939-0·995, p<0·0001). INTERPRETATION Our prediction rule, including age and four neurological tests, can give an early prognosis of an individuals ability to walk after traumatic spinal cord injury, which can be used to set rehabilitation goals and might improve the ability to stratify patients in interventional trials. FUNDING Internationale Stiftung für Forschung in Paraplegie.

Analysis of the sagittal plane after surgical management for Scheuermann's disease: a view on overcorrection and the use of an anterior release.

Study Design. A historic cohort study was conducted to investigate surgical correction and sagittal alignment in 33 patients with thoracic Scheuermann’s disease. Objective. To evaluate kyphosis correction, correction loss, sagittal balance, and the effect of an anterior release. Summary of Background Data. Currently, both posterior and anteroposterior techniques seem to produce impressive corrections for Scheuermann’s disease. However, few reports have been made on sagittal malalignment after surgery. Methods. A cohort of 33 patients who had undergone surgery for their Scheuermann’s kyphosis were reviewed: Group A: posterior technique (n = 16), Group B: anteroposterior technique (n = 17). Pre- and postoperative curve morphometry (Cobb, Ferguson, Voutsinas), balance (C7 plumb line), and Oswestry score were compared. Results. The mean follow-up period was 4.5 ± 2 years (range, 2–8.2 years). The mean preoperative kyphosis (Cobb) was 78.7° ± 8.9°, and the mean postoperative kyphosis was 51.7° ± 10.3°. At follow-up evaluation, the correction loss was 1,4° ± 3.9°. There was no difference in curve morphometry, correction, sagittal balance, average age, and follow-up period between Groups A and B. One junctional kyphosis, in Group B, was noted. After surgery, all the patients were satisfied, and the Oswestry score showed significant improvement. No neurologic complications were observed. Conclusions. Good follow-up results included a 100% follow-up rate, adequate corrections, little correction loss, lower Oswestry scores, and a high satisfaction rate in both groups. The anteroposterior treatment did not influence the curve morphometry more than posterior fusion only. In reducing postoperative sagittal malalignment, the authors believe that surgical management should aim at a correction within the high normal kyphosis range of 40° to 50°, consequently providing good results and, particularly in flexible adolescents and young adults, minimizing the necessity for an anterior release.

A methodological systematic review on surgical site infections following spinal surgery: part 1: risk factors.

Study Design. A methodological systematic review. Objective. To critically appraise the validity of risk factors for surgical site infection (SSI) after spinal surgery. Summary of Background Data. SSIs lead to higher morbidity, mortality, and increased health care costs. Understanding which factors lead to an increased risk of SSI is important for the development of prophylactic protocols to counter this risk. To date, however, no review appraising the methodological quality of studies evaluating risk factors for spinal SSIs has been published. Methods. Contemporary studies identifying risk factors for SSI after spinal surgery were searched through the Medline and EMBASE databases (January 2001 to December 2010). References were retrieved and bias-prone study features were abstracted individually and independently by 2 authors. Results. Twenty-four eligible studies were identified, including 9 (nested) case-control studies and 15 case series. Included studies covered wide variations of indications and surgical procedures. A total of 73 different types of factors were evaluated for the risk of an SSI of which 34 (47%) were reported to be significantly related to at least 1 study. Only the following risk factors—diabetes mellitus, obesity, and previous SSI—were confirmed more often (n = 11, 8, and 3, respectively) as a significant risk factor for an SSI than they were disproved (n = 7, 6, and 1, respectively). Various sources of heterogeneity were observed, including patient selection, selection and analysis of putative risk factors, and definitions of SSI outcomes. Conclusion. There is an abundance of conflicting data on risk factors for SSI after spinal surgery. Given various sources of heterogeneity observed in observational literature, there is a paucity of solid evidence for the proof of robust risk factors. The authors recommend the introduction, validation, and use of a standardized set of strongly justified eligibility criteria and well-defined candidate risk factors and spinal SSI outcomes.

Biomarkers in spinal cord injury

Study design:Literature review.Objectives:In traumatic spinal cord injury (SCI), much effort has been put into the evaluation of SCI severity and the prediction of recovery potential. An accurate prediction of the initial damage of the spinal cord that differentiates between the severities of SCI however, may help physicians in choosing a particular neuroprotective treatment in the acute phase. Neurochemical biomarkers may possibly fulfil these requirements. The aim of this review was to describe (1) the current status of neurochemical biomarkers in SCI; (2) their potential diagnostic role in SCI.Methods:MEDLINE was searched from 1966 to 2008 to identify publications concerning biomarkers in traumatic SCI.Results:The biomarkers S-100β, neuron-specific enolase, neurofilament light chain, and Glial fibrillary acidic protein are significantly increased in cases of (experimental) spinal cord injury. Furthermore, increased serum concentrations of S-100β have been correlated with an unfavourable functional outcome. Although biomarkers in SCI show promising results, considerations and shortcomings, such as polytrauma, haemolysis, extracerebral sources, and poor resuscitation, must be studied in greater detail before biomarkers can be utilised in the clinical care of SCI.Conclusions:Quantitative standards for determining the extent of SCI during the acute phase must be developed and validated. Even though increased concentrations of neurochemical biomarkers have been identified in patients with SCI, these do not yet provide a sensitive prognostic tool. Considering the limited availability of sensitive prognostic tools, neurochemical biomarkers of SCI should be evaluated and validated in future clinical trials.

ASIA impairment scale conversion in traumatic SCI: is it related with the ability to walk? A descriptive comparison with functional ambulation outcome measures in 273 patients.

Study design:Prospective multicenter longitudinal cohort study.Objectives:To determine the relationship between improvements of the American Spinal Injury Association/International Spinal Cord Society (ASIA/ISCoS) neurological standard scale (AIS) outcome measure and improvements of functional ambulatory outcome measures in patients with traumatic spinal cord injury (SCI).Setting:European multicenter study of human SCI (EM-SCI).Methods:In 273 eligible patients with traumatic SCI, acute (0–15 days) and chronic phase (6 or 12 months) AIS grades, timed up and go (TUG) test and 10-m walk test (10MWT) outcome measurements were analyzed. Subanalysis of those patients who did have AIS conversion was performed to assess its relation with functional ambulatory outcomes.Results:Studied population consisted of 161 acute phase AIS grade A patients; 37 grade B; 43 grade C and 32 acute phase AIS grade D patients. Forty-two patients (26%) converted from AIS grade A, 27 (73%) from grade B, 32 (75%) from grade C and five patients (16%) from AIS grade D. The frequencies of AIS conversions and functional ambulation recovery outcomes were significantly different (P<0.001) in patients with motor complete SCI. The ratio of patients with both recovery of ambulatory function and AIS conversion (n=101) differed significantly (P<0.001) between the acute phase AIS grade scores; AIS grade A (6/40 patients, 15%), B (9/27 patients, 33%), C (23/29 patients, 79%) and D (5/5 patients 100%).Conclusions:The AIS conversion outcome measure is poorly related to the ability to walk in traumatic SCI patients. Therefore, the authors recommend the use of functional ambulation recovery outcome measures in prognosticating the recovery of walking capacity and performance of patients with SCI.

The influence of endplate-to-endplate cement augmentation on vertebral strength and stiffness in vertebroplasty.

Study Design. Controlled in vitro trial. Objective. To study vertebral strength in relation to cement augmentation technique after vertebroplasty and to assess the influence of the biomechanical compression model on postoperative results. Summary of Background Data. In the treatment of osteoporotic vertebral fractures, the role of vertebroplasty has been well established. Biomechanical compression models thus far used, compressing vertebrae by only 25% of their initial height, did not show a correlation between cement augmentation volumes and postoperative compression strength. In these studies, even very small volumes of cement seem effective. However, these models may not realistically simulate clinically relevant osteoporotic wedge fractures. We hypothesize that, in clinically relevant osteoporotic wedge fractures, postoperative vertebral body strength is strongly dependent on endplate-to-endplate cement augmentation. Methods. Twenty-five intact osteoporotic cadaver vertebrae were obtained (10 lumbar, 15 thoracic). In 21 vertebrae, anterior wedge fractures (AO type A1.2) were created by controlled external force, with preset height reduction by 35%. After height reconstruction, 9 vertebrae were augmented endplate-to-endplate and 12 vertebrae were partially augmented with polymethylmethacrylate (PMMA). Another 4 vertebrae were compressed by only 25%. Posttreatment strength and stiffness of the vertebrae were determined by a compression test identical to the pretreatment compression protocol. Results. In the 35% compression group, posttreatment strength was significantly decreased in vertebrae that were partially augmented with cement compared with the endplate-to-endplate augmented group (767 ± 257 N vs. 1141 ± 325 N, P < 0.01). Postoperative strength amounted 106% ± 27% of preoperative strength values in the endplate-to-endplate augmented vertebrae, compared with 65% ± 18% in the partially augmented vertebrae (P < 0.001). In the 25% compression group, results in height restored and augmented vertebrae were similar to the nontreated vertebrae. Conclusions. Endplate-to-endplate PMMA augmentation restores the biomechanical properties of vertebrae in clinically relevant anterior wedge fractures. Our preliminary data suggest that biomechanical models with only 25% compressive deformation unlikely form a good model to assess the mechanical effects of cement augmentation in osteoporotic fractures.

What should an ideal spinal injury classification system consist of? A methodological review and conceptual proposal for future classifications.

Since Böhler published the first categorization of spinal injuries based on plain radiographic examinations in 1929, numerous classifications have been proposed. Despite all these efforts, however, only a few have been tested for reliability and validity. This methodological, conceptual review summarizes that a spinal injury classification system should be clinically relevant, reliable and accurate. The clinical relevance of a classification is directly related to its content validity. The ideal content of a spinal injury classification should only include injury characteristics of the vertebral column, is primarily based on the increasingly routinely performed CT imaging, and is clearly distinctive from severity scales and treatment algorithms. Clearly defined observation and conversion criteria are crucial determinants of classification systems’ reliability and accuracy. Ideally, two principle spinal injury characteristics should be easy to discern on diagnostic images: the specific location and morphology of the injured spinal structure. Given the current evidence and diagnostic imaging technology, descriptions of the mechanisms of injury and ligamentous injury should not be included in a spinal injury classification. The presence of concomitant neurologic deficits can be integrated in a spinal injury severity scale, which in turn can be considered in a spinal injury treatment algorithm. Ideally, a validation pathway of a spinal injury classification system should be completed prior to its clinical and scientific implementation. This review provides a methodological concept which might be considered prior to the synthesis of new or modified spinal injury classifications.

Is determination between complete and incomplete traumatic spinal cord injury clinically relevant? Validation of the ASIA sacral sparing criteria in a prospective cohort of 432 patients.

Study design:Prospective multicenter longitudinal cohort study.Objective:To validate the prognostic value of the acute phase sacral sparing measurements with regard to chronic phase-independent ambulation in patients with traumatic spinal cord injury (SCI).Setting:European Multicenter Study of Human Spinal Cord Injury (EM-SCI).Methods:In 432 patients, acute phase (0–15 days) American Spinal Injury Association (ASIA)/International Spinal Cord Society neurological standard scale (AIS) grades, ASIA sacral sparing measurements, which are S4–5 light touch (LT), S4–5 pin prick (PP), anal sensation and voluntary anal contraction; and chronic phase (6 or 12 months) indoor mobility Spinal Cord Independence Measure (SCIM) measurements were analyzed. Calculations of positive and negative predictive values (PPV/NPV) as well as univariate and multivariate logistic regressions were performed in all four sacral sparing criteria. The area under the receiver-operating characteristic curve (AUC) ratios of all regression equations was calculated.Results:To achieve independent ambulation 1-year post injury, a normal S4–5 PP score showed the best PPV (96.5%, P<0.001, 95% confidence interval (95% CI): 87.9–99.6). Best NPV was reported in the S4–5 LT score (91.7%, P<0.001, 95% CI: 81.6–97.2). The use of the combination of only voluntary anal contraction and the S4–5 LT and PP sensory scores (AUC: 0.906, P<0.001, 95% CI: 0.871–0.941) showed significantly better (P<0.001, 95% CI: 0.038–0.128) discriminating results in prognosticating 1-year independent ambulation than with the use of currently used distinction between complete and incomplete SCI (AUC: 0.823, P<0.001, 95% CI: 0.781–0.864).Conclusions:Out of the four sacral sparing criteria, the acute phase anal sensory score measurements do not contribute significantly to the prognosis of independent ambulation. The combination of the acute phase voluntary anal contraction and the S4–5 LT and PP scores, predicts significantly better chronic phase-independent ambulation outcomes than the currently used distinction between complete and incomplete SCI.Sponsorship:This study was granted by ‘Acute Zorgregio Oost’ and the ‘Internationale Stiftung für Forschung in Paraplegie (IFP)’.

Structural biomarkers in the cerebrospinal fluid within 24 h after a traumatic spinal cord injury: a descriptive analysis of 16 subjects

Study design:Prospective cohort study.Objectives:To characterize the cerebrospinal fluid (CSF) concentrations of glial fibrillary acidic protein, neuron specific enolase (NSE), S-100β, tau and neurofilament heavy chain (NFH) within 24 h of an acute traumatic spinal cord injury (SCI), and to correlate these concentrations with the baseline severity of neurologic impairment as graded by the American Spinal Injury Association impairment scale (AIS).Methods:A lumbar puncture was performed to obtain CSF from 16 acute traumatic SCI patients within 24 h post injury. Neurological examinations were performed within 24 h of injury and again at 6 or 12 months post injury. The correlations between the CSF concentrations and initial AIS were calculated by using Pearson correlation coefficients. In addition, an independent Student’s t-test was used to test for differences in CSF concentrations between patients of different AIS grades.Results:The CSF NSE concentrations were significantly correlated with the baseline neurologic impairment being either ‘motor complete’ (AIS A, B) or ‘motor incomplete’ (AIS C, D) (r=0.520, P<0.05). The mean S-100β concentration in motor complete patients was significantly higher compared with motor incomplete patients; 377.2 μg l−1 (s.d.±523 μg l−1) vs 57.1 μg l−1 (s.d.±56 μg l−1) (P<0.05), respectively. Lastly, the mean NFH concentration in motor complete patients was significantly higher compared with motor incomplete patient, 11 813 ng l−1 (s.d.±16 195 ng l−1) vs 1446.8 ng l−1 (s.d.±1533 ng l−1), (P<0.05), respectively.Conclusion:In this study we identified differences in the structural CSF biomarkers NSE, S-100β and NFH between motor complete and motor incomplete SCI patients. Our data showed no clear differences in any of the protein concentrations between the different AIS grades.

Methodological Systematic Review : Mortality in Elderly Patients With Cervical Spine Injury : A Critical Appraisal of the Reporting of Baseline Characteristics, Follow-up, Cause of Death, and Analysis of Risk Factors

Study Design. Methodologic systematic review. Objective. To determine the validity of reported risk factors for mortality in elderly patients with cervical spine injury. Summary of Background Data. In elderly patients with cervical spine injury, mortality has frequently been associated with the type of treatment. To date, however, no review evaluating the validity of reported risk factors for mortality in elderly patients with cervical spine injury has been published. Methods. Studies evaluating the treatment of cervical spine injuries in elderly (≥60 years of age) patients were searched through the Medline and EMBASE databases. In addition to standard methodologic details, reporting of putative confounding baseline characteristics and analysis of risk factors for mortality were appraised critically. For this purpose, patient data presented in included studies were pooled. Exploratory descriptive statistics were used for data analysis. Results. Twenty-six eligible studies were identified, including a total of 1550 pooled elderly subjects. Except for 2, all studies reported presence or absence of spinal cord injury. Details concerning the severity and/or extent of the injury were reported in 12 (46%) studies. Pre-existing comorbidities were reported in 9 studies (35%). In the pooled subjects, the cause of death was not reported in 155 of 335 deceased patients (42%). Based on own results, 18 (69%) studies reported on risk factors for mortality. Of these studies, 6 (23%) performed statistical analyses of risk factors for mortality outcomes. Only 1 study statistically adjusted potential risk factors for mortality for confounding. Conclusion. Overall, pre-existing comorbidities, concomitant injuries, follow-up and cause of death have been underreported in studies investigating the treatment of cervical spine injuries in elderly patients. To strengthen the validity of risk factors for mortality in future clinical trials, adjustments for appropriately reported putative confounders by regression analysis are mandatory.