Development of a mapping function ("crosswalk") for the conversion of scores between the Oswestry Disability Index (ODI) and the Core Outcome Measures Index (COMI).

INTRODUCTION: The Oswestry Disability Index (ODI) and the Core Outcome Measures Index (COMI) are two commonly used self-rating outcome instruments in patients with lumbar spinal disorders. No formal crosswalk between them exists that would otherwise allow the scores of one to be interpreted in terms of the other. We aimed to create such a mapping function. METHODS: We performed a secondary analysis of ODI and COMI data previously collected from 3324 patients (57 ± 17y; 60.3% female) at baseline and 1y after surgical or conservative treatment. Correlations between scores and Cohen's kappa for agreement (κ) regarding achievement of the minimal clinically important change (MCIC) score on each instrument (ODI, 12.8 points; COMI, 2.2 points) were calculated, and regression models were built. The latter were tested for accuracy in an independent set of registry data from 634 patients (60 ± 15y; 56.8% female). RESULTS: All pairs of measures were significantly positively correlated (baseline, 0.73; 1y follow-up (FU), 0.84; change-scores, 0.73). MCIC for COMI was achieved in 53.9% patients and for ODI, in 52.4%, with 78% agreement on an individual basis (κ = 0.56). Standard errors for the regression slopes and intercepts were low, indicating excellent prediction at the group level, but root mean square residuals (reflecting individual error) were relatively high. ODI was predicted as COMI × 7.13-4.20 (at baseline), COMI × 6.34 + 2.67 (at FU) and COMI × 5.18 + 1.92 (for change-score); COMI was predicted as ODI × 0.075 + 3.64 (baseline), ODI × 0.113 + 0.96 (FU), and ODI × 0.102 + 1.10 (change-score). ICCs were 0.63-0.87 for derived versus actual scores. CONCLUSION: Predictions at the group level were very good and met standards justifying the pooling of data. However, we caution against using individual values for treatment decisions, e.g. attempting to monitor patients over time, first with one instrument and then with the other, due to the lower statistical precision at the individual level. The ability to convert scores via the developed mapping function should open up more centres/registries for collaboration and facilitate the combining of data in meta-analyses.

Shorter and sweeter: the 16-item version of the SRS questionnaire shows better structural validity than the 20-item version in young patients with spinal deformity.

PURPOSE: In patients with adult spinal deformity, it was previously shown that 16 of the non-management items of the SRS-instrument showed a better fit to the theoretical four-factor model (pain, function, self-image, mental health) than did all 20 items. Whether the same phenomenon is observed in data from younger (< 20y) patients, for whom the questionnaire was originally designed, is not currently known. METHODS: Confirmatory factor analysis was used to evaluate the factor structure of the 20 non-management items of the SRS-instrument completed by 3618 young patients with spinal deformity (75.5% female; mean age, 15.0 ± 2.0 years) and of its equivalence across language versions (2713 English-speaking, 270 Spanish, 264 German, 223 Italian, and 148 French). The root mean square error of approximation (RMSEA) and comparative fit index (CFI) indicated model fit. RESULTS: Compared with the 20-item version, the 16-item solution significantly increased the fit (p < 0.001) across all language versions, to achieve good model fit (CFI = 0.96, RMSEA = 0.06). For both 16-item and 20-item models, equivalence across languages was not reached, with some items showing weaker item-loading for some languages, in particular German and French. CONCLUSION: In patients with adolescent idiopathic scoliosis, the shorter 16-item version showed a better fit to the intended 4-factor structure of the SRS-instrument. The wording of some of the items, and/or their equivalence across language versions, may need to be addressed. Questionnaire completion can be a burden for patients; if a shorter, more structurally valid version is available, its use should be encouraged.

Impact of radiologic variables on item responses of ODI, SRS22 and SF-36. in adult spinal deformity patients: differential item functioning (DIF) analysis results from a multi-center database.

PURPOSE: To determine if responses given to each question of the Scoliosis Research Society-22 (SRS22), Oswestry disability index (ODI) and Short Form-36 (SF-36) questionnaires are influenced by the radiological parameters. METHODS: Patients enrolled in a multi-centre prospectively collected adult spinal deformity database who had complete SRS22, ODI and SF-36 data at baseline and at one-year follow-up were analysed. The presence of a differential item function of each question within each score in relation to radiological parameters was analysed using a mixed Rasch model with the radiological threshold value(s) determined. RESULTS: Of those patients analysed (n = 1745; 1406 female, average age 51.0 ± 19.8 years), 944 were surgically and 801 were non-surgically treated. For the SRS22, questions (Q) 3, 5 and 18 were sensitive to almost all radiological parameters and the overall score was found sensitive to the Cobb angle. For the ODI, Q3, 6, 9 and 10 were not sensitive to any radiologic parameters whereas Q4 and 5 were sensitive to most. In contrast, only 3 of the SF-36 items were sensitive to radiological parameters. CONCLUSIONS: 78% of the SRS-22, 60% of the ODI and 8% of the questions in the SF-36 are sensitive to radiological parameters. Sagittal imbalance is independently associated with a poor overall outcome, but affects mental status and function more than pain and self-image. The assembly of questions responsive to radiological parameters may be useful in establishing a connection between changes in radiologic parameters and HRQL.

The Impact of Corrective Surgery on Health-Related Quality of Life Subclasses in Adult Scoliosis: Will Degree of Correction Prognosticate Degree of Improvement?

PURPOSE: Objectives in scoliosis corrective surgery include restoration of normal sagittal and coronal parameters to achieve patient satisfaction. HRQLs improvements remain limited after corrective surgery. The aim of this study was to evaluate the HRQL subclass variability specific to the sagittal and coronal correction in adult scoliosis surgery. METHODS: This multi-centre prospective analysis of consecutive adult spinal deformity (ASD) patients, from five European centres, only included multilevel instrumentation for scoliosis. d-(delta) values for each parameter represented pre to post-operative changes. Parameters included demographics, baseline, 1- and 2-year. HRQL outcomes (Oswestry disability index (ODI), Scoliosis Research Society (SRS)-22 and Short Form (SF36)), sagittal correction including relative spinopelvic alignment (dRSA) and coronal correction including major Cobb (dCobb) angles. RESULTS: A total of 353 patients reached 1-year and 2-year follow up. All HRQL total scores significantly improved postoperatively, including ODI, SRS-22 and SF36. HRQL subclasses which displayed persistent improvements correlated to dRSA included sex-life, self-image, fatigue, vitality, social functioning. The only HRQL subclass improvement that correlated with dCobb was self-image. CONCLUSION: Adult scoliosis surgery improves overall HRQL, having a minimal effect on each variable. Importantly, greater coronal deformity correction affects only greater self-image scores, whereas with greater sagittal correction there are many greater HRQL sub-class impacts. Correction and restoration of coronal balance is one of the surgical goals in adult scoliosis but the degree to which Cobb angle is corrected, apart from self-image, does not correlate with gains in sub-classes of HRQL. These results need to be taken into account when planning surgery.

Impact of COVID-19 on the pain and disability of patients with adult spinal deformity.

PURPOSE: To evaluate the pain and functional effect of the COVID-19 pandemic on patients with ASD reflected by their response to SRS-22, ODI, and SF-36 questionnaires. METHODS: Patients who had stable pain and functional outcome scores over the preceding 2 years were enrolled in a local prospectively collected adult spinal deformity (ASD) database. A reanalysis of their SRS22, ODI and SF-36 data 14 days into confinement were compared to their last pre-confinement scores. RESULTS: 89 patients were included in this study (average age 60.7 years, 91% female) with an average time from last FU until confinement of 9.6 months. The ODI total score worsened by 5 points post-confinement with no difference seen in personal care, walking and social life. In contrast, the SRS-22 score showed small improvements in function/activity and satisfaction, but no significant differences for the other domains. Similarly, the SF-36 showed small improvements in physical function, physical and emotional role, vitality and PCS. CONCLUSION: The global COVID-19 pandemic and ensuing confinement had variable overall effects on ASD patients, without the expected marked worsening. In addition, this study illustrates that the SRS-22 questionnaire is less influenced by environmental and psychological factors than the ODI supporting its objectivity and accuracy in the evaluation of the QoL of ASD patients.

What level of symptoms are patients with adult spinal deformity prepared to live with? A cross-sectional analysis of the 12-month follow-up data from 1043 patients.

INTRODUCTION: Previous studies suggest that a meaningful and easily understood measure of treatment outcome may be the proportion of patients who are in a "patient acceptable symptom state" (PASS). We sought to quantify the score equivalent to PASS for different outcome instruments, in patients with adult spinal deformity (ASD). METHODS: We analysed the following 12-month questionnaire data from the European Spine Study Group (ESSG): Oswestry Disability Index (ODI; 0-100); Numeric Rating Scales (NRS; 0-10) for back/leg pain; Scoliosis Research Society (SRS) questionnaire; and an item "if you had to spend the rest of your life with the symptoms you have now, how would you feel about it?" (5-point scale, dichotomised with top 2 responses "somewhat satisfied/very satisfied" being considered PASS+, everything else PASS-). Receiver operating characteristics (ROC) analyses indicated the cut-off scores equivalent to PASS+. RESULTS: Out of 1043 patients (599 operative, 444 non-operative; 51 ± 19 years; 84% women), 42% reported being PASS+ at 12 months' follow-up. The ROC areas under the curve were 0.71-0.84 (highest for SRS subscore), suggesting the questionnaire scores discriminated well between PASS+ and PASS-. The scores corresponding to PASS+ were > 3.5 for the SRS subscore (> 3.3-3.8 for SRS subdomains); ≤ 18 for ODI; and ≤ 3 for NRS pain. There were slight differences in cut-offs for subgroups of age, treatment type, aetiology, baseline symptoms, and sex. CONCLUSION: Most interventions for ASD improve patients' complaints but do not totally eliminate them. Reporting the percentage achieving a score equivalent to an "acceptable state" may represent a more stringent and discerning target for denoting treatment success in ASD. These slides can be retrieved under Electronic Supplementary Material.

Revision surgery of spinal dynamic implants: a literature review and algorithm proposal.

INTRODUCTION: Dynamic stabilization of the spine has been performed since the 1990s with the double purpose of restoring spinal segmental stability and allowing residual movement at the operated level. When we take into account the different motion-preserving devices and the spinal areas where they are applied, we can identify three categories of spinal implants: anterior cervical, anterior lumbar, and posterior lumbar. However, as in all prosthetic procedures performed in orthopedic surgery, the life span of a joint replacement device is a central topic of discussion, and this is true also for spinal dynamic devices, being revision surgery a complex procedure in specific cases. MATERIALS AND METHODS: We performed a literature review on the different dynamic spinal implants and the most common causes of failure, providing clinical cases as illustrative options for revision surgery. RESULTS: The review of the literature showed a 11.3% to 22.6% revision rate in posterior lumbar dynamic systems, with a peak of 40.6% in case of adjacent segment disease. In lumbar TDRs, infection and severe dislocations are the most frequent causes of anterior revisions, while posterior pedicle screw fixation could be a suitable option in minimal subsidence or TDR displacement. An algorithm for the planning of revision surgery is proposed. CONCLUSIONS: Surgical revision of spinal dynamic implants could be a demanding surgery especially in anterior approaches. Anterior cervical revision remains globally safe, but careful preoperative evaluation of vessels and ureter are suggested to avoid intraoperative complications in the lumbar spine. In posterior revision, a proper sagittal alignment of the spine should be restored. These slides can be retrieved under Electronic Supplementary Material.

Validation of a Simplified SRS-Schwab Classification Using a Sagittal Modifier.

STUDY DESIGN: Multicenter, prospective study of consecutive adult spinal deformity (ASD) patients. OBJECTIVE: To Validate Schwab's classification accuracy for surgical indication, and to evaluate a simplified sagittal modifier. SUMMARY OF BACKGROUND DATA: The SRS-Schwab Radiologic Classification based on clinical impact parameters, offers 27 different sagittal classification possibilities regarding sagittal vertical alignment (SVA), pelvic tilt (PT), and pelvic incidence-lumbar lordosis (PI-LL). The high number of classification possibilities makes it complex to use. METHODS: Inclusion criteria were ASD patients, presenting at least 1 criteria: Cobb ≥ 20°, SVA ≥ 5 cm, thoracic kyphosis ≥ 60°, or PT ≥ 25°. A total of 1,004 patients (410 nonoperative and 594 operative) were classified regarding SVA, PT, and PI-LL (0, +, ++), and 27 possibilities were identified. Categories were formed by adding the number of + signs, considering PT, SVA, and PI-LL. Three specific categories were identified: Aligned: 0 +; Moderate deformity: 1 to 3+; and Severe deformity: 4 to 6+. A χ-square test was performed for surgical indication (operated or not) and an analysis of variance was performed to evaluate the relationship between categories and Oswestry Disability Index (ODI). Probability <.05 was considered significant. RESULTS: Significant differences for HRQoL scores and surgical indication were found in the 27 sagittal parameter possibilities. For nonoperative patients, 230 (56.1%) were classified as aligned, 145 (35.4%) as moderate, and 35 (8.5%) as severe. For operative patients, there were 200 (33.7%), 215 (36.2%), and 179 (30.1%) in each respective subgroup. For HRQoL scores and surgical indication, no significant differences were found within each category, but significant differences were found when comparing the subgroups. CONCLUSIONS: Despite the correlation between SRS-Schwab classification and surgical indication, it is complex to use, with a total of 27 possibilities regarding sagittal modifiers. This simplification into three categories offers more readability, without losing any significant information, and could replace Schwab sagittal modifiers. In association with other parameters, they could be used for decision-making. LEVEL OF EVIDENCE: Level II.

Anterior cervical spine blood supply: a cadaveric study.

PURPOSE: To describe the origin of the vessels supplying the anterior sub-axial cervical vertebrae (C3-C7) to further understand their potential influence on anterior bone loss after anterior cervical spinal surgery. METHOD: Cadaveric dissection was performed on ten adult human necks after latex perfusion of their subclavian, common carotid and vertebral arteries. The nutrient vessels of the sub-axial cervical spine were identified and traced to their origin. The course and distribution of these vessels and their nutrient foraminae are described. RESULTS: In all cases the anterior nutrient vessels were derived from the thyro-cervical trunk with branches that passed over the longus coli muscles forming a leash of vessels in the pre-vertebral fascia which subsequently extended in a frond-like pattern to pass onto the anterior aspect of vertebrae. The more cranial the cervical level the fewer the number of nutrient vessels and foraminae. The distribution of the foraminae on the anterior vertebral body followed the oblique supero-medial course of the nutrient vessels. CONCLUSION: Nutrient vessels perforate the cervical vertebrae on their anterior surface. These are derived from a leash of vessels that lie within the pre-vertebral fascia overlying the longus coli muscles. The origin of these vessels is the ascending cervical artery with a variable contribution from the transverse cervical artery.

Factors associated with having an indication for surgery in adult spinal deformity: an international european multicentre study.

PURPOSE: The aim of this study was to evaluate factors that distinguish between patients with adult spinal deformity (ASD) with and without an indication for surgery, irrespective of their final treatment. METHODS: Baseline variables (demographics, medical history, outcome measures, coronal, sagittal and neurologic parameters) were evaluated in a multicentre, prospective cohort of patients with ASD. Multivariable analyses were carried out for idiopathic and degenerative patients separately with the dependent variable being "indication for surgery" and baseline parameters as independent variables. RESULTS: In total, 342 patients with degenerative ASD and 624 patients with idiopathic ASD were included in the multivariable models. In patients with degenerative ASD, the parameters associated with having an indication for surgery were greater self-rated disability on the Oswestry Disability Index [odds ratio (OR) 1.04, 95% confidence interval (CI) 1.02-1.07] and a lower thoracic kyphosis (OR 0.97 95% CI 0.95-0.99), whereas in patients with idiopathic ASD, it was lower (worse) SRS self-image scores (OR 0.45 95% CI 0.32-0.64), a higher value for the major Cobb angle (OR 1.03 95% CI 1.01-1.05), lower age (OR 0.96 95% CI 0.95-0.98), prior decompression (OR 3.76 95% CI 1.00-14.08), prior infiltration (OR 2.23 95% CI 1.12-4.43), and the presence of rotatory subluxation (OR 1.98 95% CI 1.11-3.54) and sagittal subluxation (OR 4.38 95% CI 1.61-11.95). CONCLUSION: Specific sets of variables were found to be associated with an indication for surgery in patients with ASD. These should be investigated in relation to patient outcomes for their potential to guide the future development of decision aids in the treatment of ASD. These slides can be retrieved under Electronic Supplementary Material.

Factor analysis of the SRS-22 outcome assessment instrument in patients with adult spinal deformity.

PURPOSE: Designed for patients with adolescent idiopathic scoliosis, the SRS-22 is now widely used as an outcome instrument in patients with adult spinal deformity (ASD). No studies have confirmed the four-factor structure (pain, function, self-image, mental health) of the SRS-22 in ASD and under different contexts. Factorial invariance of an instrument over time and in different languages is essential to allow for precise interpretations of treatment success and comparisons across studies. This study sought to evaluate the invariance of the SRS-22 structure across different languages and sub-groups of ASD patients. METHODS: Confirmatory factor analysis was performed on the 20 non-management items of the SRS-22 with data from 245 American English-, 428 Spanish-, 229 Turkish-, 95 French-, and 195 German-speaking patients. Item loading invariance was compared across languages, age groups, etiologies, treatment groups, and assessment times. A separate sample of SRS-22 data from 772 American surgical patients with ASD was used for cross-validation. RESULTS: The factor structure fitted significantly better to the proposed four-factor solution than to a unifactorial solution. However, items 14 (personal relationships), 15 (financial difficulties), and 17 (days off work) consistently showed weak item loading within their factors across all language versions and in both baseline and follow-up datasets. A trimmed SRS (16 non-management items) that used the four least problematic items in each of the four domains yielded better-fitting models across all languages, but equivalence was still not reached. With this shorter version there was equivalence of item loading with respect to treatment (surgery vs conservative), time of assessment (baseline vs 12 months follow-up), and etiology (degenerative vs idiopathic), but not age (< vs ≥50 years). All findings were confirmed in the cross-validation sample. CONCLUSION: We recommend removal of the worst-fitting items from each of the four domains of the SRS-instrument (items 3, 14, 15, 17), together with adaptation and standardization of other items across language versions, to provide an improved version of the instrument with just 16 non-management items.

Delayed post-operative tension pneumocephalus and pneumorrhachis.

INTRODUCTION: The incidence of pneumocephalus and pneumorrhachis after spinal surgery is unknown, with a paucity of literature on this complication. MATERIALS AND METHODS: We present the first published case of delayed onset tension pneumocephalus and pneumorrhachis associated with spinal surgery. RESULTS: This complication occurred from a cerebro-spinal fluid (CSF) leak after posterior instrumentation removal and was successfully treated with emergent wound debridement and the formation of a CSF fistula. CONCLUSIONS: This case illustrates that delayed post-operative tension pneumocephalus and pneumorrhachis can occur after spinal surgery in a patient with a CSF leak. It also illustrates that pneumocephalus and pneumorrhachis can be easily diagnosed with cross-sectional CT imaging. Furthermore, in a patient with rapid deterioration emergent surgical debridement may be necessary. Lastly, if the dural tear cannot be identified intra-operatively, the formalization of a CSF fistula should be considered.

Erratum to: Delayed post-operative tension pneumocephalus and pneumorrhachis.

Unfortunately, two author names were missed out in author group of the original publication.

Five-year outcomes of the First Distal Uninstrumented Vertebra after posterior fusion for Adolescent Idiopathic Scoliosis Lenke 1 or 2.

BACKGROUND: Tilt of the First Distal Uninstrumented Vertebra (FDUV) reflects changes in the main curve and compensatory lumbar curve after posterior fusion to treat thoracic Adolescent Idiopathic Scoliosis (AIS). HYPOTHESIS: FDUV tilt 5 years or more post-fusion depends chiefly on reduction of the main curve and on other factors such as selection of the last instrumented vertebra. MATERIAL AND METHOD: A multicenter retrospective cohort of 182 patients with Lenke 1 or 2 AIS treated with posterior instrumentation and followed up for a mean of 8 years and a minimum of 5 years was studied. The patients were divided into two groups based on whether tilt of the upper endplate of the FDUV was ≤5° or >5°at last follow-up. Variables associated with tilt were identified by multiple logistic regression. RESULTS: Six variables were significantly associated with FDUVtilt: percentage of correction at last follow-up, correction loss, lumbar modifier B, number of instrumented vertebrae, inclusion within the instrumentation of the distal neutral vertebra, and inclusion within the instrumentation of the lowest vertebra intersected by the central sacral vertical line. DISCUSSION AND CONCLUSION: The main variables associated with FDUVtilt ≤5° were a final correction percentage ≥60% and absence of correction loss between the postoperative period and last follow-up. Given the stable reduction provided by contemporary instrumentations, we recommend selective thoracic fusion of Lenke 1 or 2 AIS with lumbar modifiers A, B, and C. The lowest instrumented vertebra should be either the neutral vertebra or the vertebra intersected by the central sacral vertical line if it is distal to the neutral vertebra. LEVEL OF EVIDENCE IV: Retrospective multicenter study.

Evolution and complications after surgery for spine deformation in patients with Parkinson's disease.

INTRODUCTION: Surgical treatment of spinal deformity is high risk in patients suffering from Parkinson's disease (PD). Several series have already reported a high rate of complications. However, none of these studies included more than 40 patients and none of the risk factors of complications were described. The aim of this study was to describe the rate and risk factors of revision surgery as well as the clinical outcome at the last visit in a large multicenter study of PD patients operated for spinal deformities. METHODS: A multicenter retrospective study included arthrodesis for spinal deformity in patients with PD. Clinical and surgical data including revision surgeries were collected. Assessment of functional outcomes at last follow-up was classified in 3 grades and spinal balance was assessed on anteroposterior and lateral plain X-rays of the entire spine. RESULTS: Forty-eight patients were included. Median age was 67 years old (range 41-80). Median follow-up was 27 months. The rate of surgical revision was 42%. Eighty per cent of revisions were performed for chronic mechanical complication. Global results were considered to be good in 17 patients (35%), doubtful in 17 patients (35%) and a failure in 14 patients (30%), for the whole series. CONCLUSIONS: The results of surgery for spinal deformities in patients with Parkinson disease vary with a high rate of complications and revisions. Nevertheless, these results should be seen in relation to the natural progression of these spinal deformities once spinal imbalance has developed. The association between preoperative clinical balance and final outcome suggests that early surgery can probably play a role in treatment. LEVEL OF EVIDENCE: Level IV (e.g. case series).

Lumbar spinal muscles and spinal canal study by MRI three-dimensional reconstruction in adult lumbar spinal stenosis.

BACKGROUND: Lumbar spinal stenosis is degenerative disc disease most common manifestation. If stenosis degree seems poorly related to symptom severity, lumbar muscles role is recognized. Many studies report imaging methods, to analyze muscle volumes and fat infiltration (FI), but remain limited due to the difficulty to represent entire muscle volume variability. Recently a 3D muscle reconstruction protocol (using the deformation of a parametric specific object method (DPSO) and three-point Dixon images) was reported. It offers the ability to evaluate, muscles volumes and muscle FI. PURPOSE: To describe, in a lumbar spinal stenosis population, muscle volumes, muscle FI and lumbar spinal canal volume with 3D MRI images reconstructions. MATERIALS AND METHODS: Ten adults presenting L4-L5 lumbar stenosis, were included. After specific MRI protocol, three-dimensional, muscle and spinal canal, reconstructions were performed. Muscle (psoas and paraspinal muscles) volumes and fat infiltration (FI), the spinal canal volume, age, and height were correlated one to each other with Spearman correlation factor. An ANOVA was performed to evaluate the intervertebral level influence (P≤0.05). RESULTS: Muscle volumes correlated with height (r=0.68 for psoas). Muscles FI correlated with age (r=0.66 for psoas) and lumbar spinal canal volume (r=0.91). Psoas and paraspinal volumes were maximum at L3-L4 level whereas FI increased from L1-L2 to L5-S1 level. DISCUSSION: These first results illustrate the importance to consider muscles entirely and report correlations between muscles FI, lumbar spinal canal volume and age; and between muscle volumes and patients height. Muscle degeneration seems more related to muscle FI than muscle volume. LEVEL OF EVIDENCE: 3.

Global tilt: a single parameter incorporating spinal and pelvic sagittal parameters and least affected by patient positioning.

PURPOSE: Regarding the close interaction between the spinal alignment and the pelvis orientation, no parameter is routinely used to describe and to evaluate the global spinopelvic balance, taking into account simultaneously the spinal part and the pelvic part of the global alignment. We described the global tilt (GT) that could analyze malalignment considering the spine and the pelvis simultaneously. From a geometrical point of view, the global tilt is the sum of the pelvic tilt (PT) and the C7 vertical tilt (angular value of sagittal vertical axis). The aim of this study is to evaluate the global tilt with comparison to PT and sagittal vertical axis (SVA), with the hypothesis that GT would be the least sensitive to positional changes. METHODS: A cohort of 22 patients with sagittal malalignment was identified from a multicentric database of adult spinal deformities (ASD). Inclusion criteria were age >30 years, SVA > 40 mm and/or PT > 20°. All patients had full spine EOS radiographs in positions 1 and 2 (P1 and P2), in which the patient was asked to stand and put his hands on his shoulders without any effort (P1), or to make an effort to be as straight as possible (P2). PT, SVA and GT were measured in both positions and changes between P1 and P2 were calculated and compared using Student's t test with significance level at p < 0.05. RESULTS: No significant changes were observed for GT; SVA and PT were significantly influenced by patient positioning. SVA decreased and PT increased for all cases in P2 whereas the changes in GT were in either direction. The average increase in PT was 7.1° (±5.4) or 30.8 % (±24.9); decrease in SVA was 45.1 mm (±25.6) or 60.0 % (±44.2) while the change in GT was 4.4° (±3.3) or 12.6 % (±9.3). DISCUSSION: GT appears to be less affected by the patient's position compared to SVA and PT. This seems logical because GT contains both spinal alignment and pelvic compensation; it is not affected by their changes in opposing directions. CONCLUSION: GT appears to be the most reliable single sagittal plane parameter in ASD. It is the least affected by patient position and incorporates both the pelvic and the spinal alignment within one measure.

Anatomic feasibility of a new endopelvic approach for iliac crest bone harvesting.

PURPOSE: For the past few years, anterior exposure for surgery of the lumbar spine has gained popularity for the treatment of disk disease or spondylosis. Cancellous bone remains the gold standard for fusion. Iliac crest bone harvesting is safe but there are donor site complications. Bone substitutes exist, like recombinant human bone morphogenic protein-2 rhBMP-2. This alternative offers a high rate of fusion but with local and general complications. The aim of our study is to show the feasibility of an endopelvic approach for iliac bone crest harvesting to avoid donor site complication. METHOD: Twenty anterior retroperitoneal lumbar spine approaches have been realized in the anatomy department of the University of Bordeaux. The volumes of cancellous bone have been measured and procedure complications have been reported. RESULTS: The mean volume of cancellous bone was 5.9 cc, the maximum volume was 8.2 cc and the minimum volume was 4.5 cc. No complications have been reported during the approach or the bone harvesting. CONCLUSIONS: Anterior retroperitoneal approach for iliac bone crest harvesting is a safe way to obtain sufficient volume of cancellous bone for a single lumbar spinal fusion. This exposure avoids the risks of an iliac crest donor site complications or rhBMP-2 complications.

Early reintervention after anterior cervical spine surgery: Epidemiology and risk factors: A case-control study.

INTRODUCTION: Anterior cervical spine surgery is a frequent and effective procedure; complications are rare, but potentially fatal. The objective of the present study was to assess epidemiology and risk factors for early reintervention in anterior cervical spine surgery. METHODS: A retrospective case-control study recruited 2319 patients operated on in our department, with 7 years' follow-up. Incidence and prevalence of causes of early reintervention were analyzed. Each case was matched to 2 controls from the same source population. Risk factors were identified and odds ratios (OR) were calculated. RESULTS: Thirteen patients (0.6%: 3 female, 10 male; mean age, 59±12 years) underwent surgical reintervention within 72hours. Causes comprised: retropharyngeal hematoma (0.2%), epidural hematoma (0.3%) and dural breach (0.04%). As risk factor for early reintervention, only ASA score≥3 proved significant (OR: 5.5; 95% confidence interval: 1.1-29.85). As risk factor for epidural hematoma, only smoking proved significant (OR: 14.67; 95% confidence interval: 1.16-185.29). No risk factors emerged for onset of retropharyngeal hematoma. CONCLUSION: ASA score≥3 and smoking entail risk of epidural hematoma and early reintervention. Postoperative pain, neurologic deficit, dysphagia, dysphonia, dyspnea and agitation suggest onset of complications, requiring necessary measures to be taken. Implementation of drainage fails to prevent such complications.