Adult spinal deformity correction surgery using age-adjusted alignment thresholds: clinical outcomes and mechanical complication rates. A systematic review of the literature.

PURPOSE: Adult spinal deformity (ASD) surgery gives good clinical outcomes but has a high rate of mechanical complications (MC). In 2016, Lafage described the age-adjusted alignment thresholds (AAAT) to adapt the correction in relation to patient's age proposing less aggressive corrections for the elderly population. The aim of this review was to clarify the effectiveness of AAAT to achieve good health-related quality of life (HRQoL) and their relationship with post-operative MC. MATERIALS AND METHODS: We performed a review of the literature, including articles reporting data on post-operative HRQoL and MC rates in relation to the AAAT. Data were stratified according to whether they matched the AAAT, dividing the population in undercorrected (U), matched (M) and overcorrected (O). The quality of the included studies was assessed using the GRADE and MINORS systems. RESULTS: Six articles reporting data from 1,825 patients were included. The different categories (U, M and O) had homogeneous pre-operative sagittal parameters (p > 0.05) that became statistically different after surgeries (p < 0.05). Proximal junctional kyphosis (PJK) was more frequent in the O group compared to U (p = 0.05). Post-operative HRQoL parameters were similar in the 3 groups (p > 0.05). The quality of the included studies was generally low with a high bias risk. CONCLUSION: The results extrapolated from this review are interesting, as for the same HRQoL the U group had a lower MC rate. Unfortunately, the results are inconsistent, mainly because of the low quality of the included studies and the lack of reporting of some important patient- and surgery-related factors.

GAP score potential in predicting post-operative spinal mechanical complications: a systematic review of the literature.

PURPOSE: In 2017, the GAP score was proposed as a tool to reduce mechanical complications (MC) in adult spinal deformity (ASD) surgery: the reported MC rate for the GAP proportioned category was only 6%, which is clearly lower to the MC rate reported in the literature. The aim of this study is to analyse if the most recent literature confirms the promising results of the original article. MATERIALS AND METHODS: Using the PRISMA flow chart, we reviewed the literature to analyse GAP score capacity in predicting MC occurrence. We included articles clearly reporting ASD surgery MC stratified by GAP categories and the score's overall capacity to predict MC using the area under the curve (AUC). The quality of the included studies was evaluated using GRADE and MINORS systems. RESULTS: Eleven retrospective articles (1,517 patients in total) were included. The MC distribution per GAP category was as follows: GAP-P, 32.8%; GAP-MD, 42.3%; GAP-SD, 55.4%. No statistically significant difference was observed between the different categories using the Kruskal-Wallis test (p = 0.08) and the two-by-two Pearson-Chi square test (P Vs MD, p = 0.300; P Vs SD, p = 0.275; MD Vs SD, p = 0.137). The global AUC was 0.68 ± 0.2 (moderate accuracy). The included studies were of poor quality according to the GRADE system and had a high risk of bias based on the MINORS criteria. CONCLUSION: The actual literature does not corroborate the excellent results reported by the original GAP score article. Further prospective studies, possibly stratified by type of MC and type of surgery, are necessary to validate this score.

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients.

PURPOSE: Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies. METHODS: The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed. RESULTS: Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02). CONCLUSION: Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Revision after spinal stenosis surgery.

PURPOSE: To make a literature review on spinal stenosis recurrence after a first surgery and edit rules to avoid this complication. METHODS: We conducted two separate PUBMED searches to evaluate the revision post-stenosis and degenerative scoliosis surgery using the terms: lumbar vertebrae/surgery, spinal stenosis, spine, scoliosis and reoperation. The resulting papers were categorized into three groups: (1) those that evaluated reoperation post-simple decompression; (2) those that evaluated spinal decompression and fusion for short (3 levels or less) or long (more than 3 levels) segment spinal fusion; and (3) those diagnosing the stenosis during the surgery. RESULTS: (1) We found 11 relevant papers that only looked at revision spine surgery post-laminectomy for spinal stenosis. (2) We found 20 papers looked at reoperation post-laminectomy and fusion amongst which there were two papers specifically comparing long-segment (> 3 level) and short-segment (3 or less levels) fusions. (3) In the unspecified group, we found only one article. Fifteen articles were excluded as they were not specifically looking at our objective criteria for revision surgery. In regard to revision post-adult deformity surgery, we found 18 relevant articles. CONCLUSIONS: After this literature review and analysis of post-operative stenosis, it seems important to provide some advice to avoid revision surgeries more or less induced by the surgery. It looks interesting when performing simple decompression without fusion in the lumbar spine to analyse the risk of instability induced by the decompression and facet resection but also by a global balance analysis. Regarding pre-operative stenosis in a previously operated area, different causes may be evocated, like screw or cage malpositionning but also insufficient decompression which is a common cause. Intraoperatively, the use of neuromonitoring and intraoperative CT scan with navigation are useful tool in complex cases to avoid persisting stenosis. Pre-op analysis and planning are key parameters to decrease post-op problems. These slides can be retrieved under Electronic Supplementary Material.

Sagittal balance of the spine.

The static sagittal balance of the normal spine is a physiological alignment of the spine in the most efficient manner by the muscular forces. During gait, this balance is constantly thwarted by single-foot support. This analysis involves the study of parameters which are now well defined. The pelvic incidence is constant, and the sacral slope and the pelvic tilt are positional. The cervical parameters are the upper (O-C2) and lower cervical curvatures (C2-C7), the C7 slope, the spino-cranial angle and the vertical cervical offset. At the thoracic and lumbar level, they are, respectively, kyphosis and lordosis. The OD-HA (odontoid hip axis) angle is the most efficient parameter to analyse the global balance. The average values of these parameters are reported with the new 3D measurements by Le Huec et al. The relationship between these different parameters was analysed, and Roussouly proposed his classification of the different spine shape. Ageing makes it possible to show compensation mechanisms at three levels: spinal, pelvic and lower limbs. Understanding these different data allows for better planning of the surgical management of the patients. Global evaluation of the entire spine and the measurement of the aforementioned parameters allow to determine the extent of the correction to be performed during surgery. Taking these parameters into account also enables us to understand the complications involved in this type of surgery: transitional syndromes or junctional syndromes. Integration of these parameters into the study of gait is an area still under investigation. These slides can be retrieved under Electronic Supplementary Material .

Correction to: Sagittal balance of the spine.

The Fig. 20 is not from the study by Shiba et al., but is a courtesy from Dr. Stéphane Armand, Laboratory of Kinesiology, Geneva University Hospitals, Geneva, Switzerland.

Sagittal balance measures are more reproducible when measured in 3D vs in 2D using full-body EOS® images.

PURPOSE: An innovative low-dose X-ray biplanar imager (EOS®) allows measurement of the whole-body in standing-position which is necessary for the evaluation of spinal deformities. METHODS: A total of 60 asymptomatic subjects (ages 20-81 years) were evaluated using the 3D workflow called postural assessment and 2D measures. Subjects were measured twice each by two new observers following training, including: lordosis/kyphosis, pelvic parameters, sagittal-vertical axis, and spinal-sacral angle. Intra- and inter-observer reproducibility and similarity were compared between 2D and 3D measures. RESULTS: The intraclass correlation coefficient (ICC) was very high for the 3D measures (>0.9) and excellent for the 2D measures (>0.75). In all cases, the overall mean absolute difference between repeated 3D measures was less than 2°, or 2 mm. For all parameters, the inter- and intra-observer reproducibility in 3D measures were significantly superior to 2D measures (p < 0.03). CONCLUSION: This study demonstrated that 3D measures have better reproducibility than 2D for sagittal balance. KEY POINTS: • Reproducibility of sagittal balance 2D/3D measurements was evaluated using EOS® full-body radiographs. • Inter- and intra-observer reproducibility were significantly superior for 3D measures vs. 2D. • 3D measures have better reproducibility than 2D for sagittal balance.

Thoracic osteotomy for Gorham-Stout disease of the spine: a case report and literature review.

INTRODUCTION: Gorham-Stout syndrome is an aggressive, non-heritable skeletal disease characterized by osteolysis following minor trauma. The primary involvement of the spine is less common (10 %) and has been described in only about 20 cases; there is no consensus about the best way to treat this condition. PURPOSE OF THE STUDY: To report a case of Gorham-Stout syndrome involving the thoracic spine and to review the literature to suggest a post-operative treatment to prevent osteolysis. CASE REPORT: A thirty-year-old female patient was admitted to the unit in March 2013 for a pathologic T4 fracture. X-rays and CT scan revealed the onset of T4 osteolysis and an increase in thoracic kyphosis (the local kyphosis was up to 100°). We performed surgery by posterior approach, combining posterior fixation with screws and rods from T3 to T9, decompression and vertebral osteotomy of 65°. The immediate outcome of surgery was good and the patient returned home after 24 days. At 6 and 12 months of follow-up, the patient was walking normally with no neurological sequelae. CONCLUSION: We report a case of Gorham-Stout syndrome involving the thoracic spine that was successfully treated by interpedicular osteotomy associated with a 6 month follow-up. We suggest that this strategy can provide good results, because after fusion, the disease process remains stable. Because of the lack of cases reported, surgeons must be careful when using multiple treatments, because these treatments have many side effects. LEVEL OF EVIDENCE: Level IV case report.

Maverick total disc arthroplasty performs well at 10 years follow-up: a prospective study with HRQL and balance analysis.

PURPOSE: The treatment of low back pain associated to Disc Degenerative Disease (DDD) is still controversial. Segmental Fusion is the gold standard, but many studies have reported that motion-preserving devices bring substantial clinical benefits to patients. Concerns on the associated complications and on the long-term clinical effectiveness of such instrumentations are still present and have led recently to a decrease of the number of Lumbar Total Disk Replacements (TDR). The objective of this prospective study is to present the clinical and radiographic outcomes of the Maverick Lumbar disk prostheses (Medtronic, TE, Memphis, USA) at long-term follow-up. METHODS: Prospective, single center study of clinical outcome of the treatment with Maverick lumbar Prosthesis of patients with low back pain from DDD resistant to conservative treatment. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Visual analog scale (VAS), Oswestry disability index (ODI) and 36-Item Short Form Health Survey questionnaire were assessed to study clinical outcomes. Radiographic studies allowed measurements of range of motion, adjacent segment disease and pelvic and lumbar parameters. RESULTS: From an initial cohort of 87 patients who underwent TDR between 2003 and 2007 with the Maverick prosthesis, 61 were available at Final follow-up (70%). The clinical outcomes measured by VAS and ODI showed a significant improvement in all the postoperative stages of the follow-up (FU). At 10 years-FU, ODI experienced a mean decrease of 21.1 points, VAS for back pain decreased up to 3.85 and substantial clinical benefit was reached for 55.6% of the patients. Although Mobility of the prosthesis was preserved in 76.8% of the cases, TDR was not clearly protective against ALD. CONCLUSIONS: A significant, clinically relevant, and lasting reduction of back pain has been achieved in patients who underwent a total disk arthroplasty or a Hybrid construct with Maverik prosthesis. TDR is a safe and effective technique to decrease pain in patients with one or two levels of DDD.

Vaccine development to prevent Staphylococcus aureus surgical-site infections.

BACKGROUND: Staphylococcus aureus surgical-site infections (SSIs) are a major cause of poor health outcomes, including mortality, across surgical specialties. Despite current advances as a result of preventive interventions, the disease burden of S. aureus SSI remains high, and increasing antibiotic resistance continues to be a concern. Prophylactic S. aureus vaccines may represent an opportunity to prevent SSI. METHODS: A review of SSI pathophysiology was undertaken in the context of evaluating new approaches to developing a prophylactic vaccine to prevent S. aureus SSI. RESULTS: A prophylactic vaccine ideally would provide protective immunity at the time of the surgical incision to prevent initiation and progression of infection. Although the pathogenicity of S. aureus is attributed to many virulence factors, previous attempts to develop S. aureus vaccines targeted only a single virulence mechanism. The field has now moved towards multiple-antigen vaccine strategies, and promising results have been observed in early-phase clinical studies that supported the recent initiation of an efficacy trial to prevent SSI. CONCLUSION: There is an unmet medical need for novel S. aureus SSI prevention measures. Advances in understanding of S. aureus SSI pathophysiology could lead to the development of effective and safe prophylactic multiple-antigen vaccines to prevent S. aureus SSI.

Meta-analysis of the effects of genetic polymorphisms on intervertebral disc degeneration.

INTRODUCTION: Chronic low back pain is a significant public health issue. Both its direct and indirect cost represents tens of billions of US dollars. Although chronic low back pain can be the result of many factors, the predominant cause is disc degeneration. Recent studies have shown genetic involvement in up to 74% of cases. This study aimed to evaluate genetic risk factors of disc degeneration by performing a systematic analysis of association studies. The objective is to provide a guide for practice by assessing the clinical relevance of current information. METHODS AND MATERIALS: We performed a meta-analysis of 3122 items collected from 6 databases. 74 articles were selected according to our inclusion criteria. 18 (24%) could be grouped into 16 meta-analyses of 16 mutations in 12 genes. The statistics of the meta-analysis were conducted through Revman 5.1 software. RESULTS: The items included are 10,250 cases and 14,136 controls. The GOLD range from 3.42 to 0.38. Two alleles were significantly associated with disc degeneration: IL-6 rs1800797 and MMP-9 rs17576 and one proved to be protective: IL-6 rs1800795. 13 meta-analyses did not yield significant results and methodological heterogeneity. DISCUSSION: The results highlight the lack of methodological rigor in most of the studies. The absence of international clinical and radiological classification of early disc degeneration, limits the homogeneity of studies. Understanding which populations are predisposed to this significant public health problem may change our approach to diagnostic and therapeutic methods. This work opens up enormous opportunities to provide a genetic solution and consider new diagnostic and therapeutic means to this public health problem.

Normative spino-pelvic parameters in patients with the lumbarization of S1 compared to a normal asymptomatic population.

INTRODUCTION: Normal spino-pelvic values for patients with lumbarization of S1 have not been described in the literature. Presented are the normal values for this population group, the prevalence of S1 lumbarization, and the correlation between pelvic incidence (PI) and lumbar lordosis (LL) in this group. METHODS: Two databases of asymptomatic patients were combined to identify 11 patients with the lumbarization of S1. The whole spine images were used to measure the true prevalence rate. Lumbar 3D EOS models were built to measure spino-pelvic parameters for the lumbarization group compared to the asymptomatic population. Seven patients appeared at first to have six lumbar vertebrae, but counting caudally from C2 showed this was not the case. RESULTS: 11/268 patients demonstrated the lumbarization of S1 to give a true prevalence rate of 4.1 %. The lumbarization group demonstrated a statistically significant difference with regard to PI, PT, and SS, and total lordosis measured from superior endplate of L1 to the superior endplate of the first fixed sacral segment. L6I was not significantly correlated to lordosis; however, PI did have a significant correlation with lordosis. Lordosis could be estimated in this group by the equation: [Formula: see text]. CONCLUSION: Incomplete imaging of the spine may lead to false estimation of the prevalence of lumbarization. Patients with lumbarization have higher lordosis values and lordosis can now be estimated during pre-operative planning for this group.

Normative values for the L5 incidence in a subgroup of transitional anomalies extracted from 147 asymptomatic subjects.

PURPOSE: Pelvic incidence angle is not always measurable due to lumbosacral transitional vertebrae (LSV). The fifth lumbar vertebra (L5) is rarely abnormal. The purpose of this study was to quantify from full-body standing X-rays, the L5 incidence angle (L5I) in a normal asymptomatic population and to correlate it with standard spino-pelvic parameters taking the sacrum (S1) as a reference. METHODS: One hundred and forty seven asymptomatic volunteers were enrolled. The ethics committee approved the study protocol. Subjects underwent a low-dose full spine X-ray. 3D reconstructions were obtained and L5I was measured using the upper L5 endplate as the reference instead of the S1 endplate. A group of subjects with LSV was identified and subdivided in two subgroups. Standard spino-pelvic parameters and normative values for the L5 parameters were obtained. Statistical correlations were calculated between the standard and L5 parameters as well as L5I with L1-L5 lordosis in both subgroups. RESULTS: Twenty two (14.96 %) subjects with LSV were found. Ten of these had an unidentifiable S1 endplate due to a sacralisation of L5. Mean values for the L5I, L5 tilt, L5 slope and L1-L5 lordosis were, respectively, 22.43, 4.65, 17.73, and 45.51 for normal subjects (N = 137) and 32.75, 6.63, 26.38, and 55.02 for sacralisation of L5 subjects (N = 10). Mathematical relationship found: L5I = 0.7641 * PI - 17.725 (R = 0.83) and L1-L5 = 0.67 * L5I + 30.7 (R = 0.64). CONCLUSION: This prospective study is first to provide normative spino-pelvic values at the L5 level in an asymptomatic population, particularly in case of (LSV) sacralisation of L5 (N = 10) where L5I and L1-L5 lordosis appears to be 10° more important than in normal population. We propose L5I as a new spino-pelvic parameter to restore in case of L5-S1 disk disease. These normative values will help to control peri-operatively the adequate lordosis restoration, in the presence of LSV.

Clinical and radiological outcomes of lumbar posterior subtraction osteotomies are correlated to pelvic incidence and FBI index : Prospective series of 63 cases.

PURPOSE: Pedicle subtraction osteotomy (PSO) is one of the surgical options for treating alignment disorders of the fused spine (due to post-surgical fusion or related to arthritis). It enables satisfactory sagittal realignment and improved function due to economic sagittal balance. The aim of this study was to analyze clinical and radiological results of PSO after a minimum follow-up of 2 years and demonstrate the benefit of sub-group analysis as a function of pelvic incidence (PI). METHODS: A descriptive prospective single center study of 63 patients presenting with spinal global malalignment who underwent correction by PSO. Function was assessed by the Oswestry disability index (ODI), a visual analog scale of lumbar pain (VAS) and a SF-36 questionnaire. Radiographic analyses of pre- and post-operative pelvic-spinal parameters were performed on X-rays obtained by EOS(®) imaging after 3D modeling. Global analysis and analysis of sub-groups as a function of pelvic incidence were performed and the full balance integrated index (FBI) was calculated. RESULTS: this series showed a marked clinical improvement and significant progress of functional scores. Global post-operative radiological analysis showed a significant improvement in all pelvic and spinal parameters. The mean correction obtained after PSO was 31.7° ± 8.4°, hence global improvement of lumbar lordosis of 22°. The sagittal vertical angle (SVA) decreased from +9 cm before surgery to +4.3 cm after surgery. Sub-group analysis demonstrated greater improvement in pelvic tilt, sacral slope and spinal parameters of patients with a small or moderate pelvic incidence; all had an FBI index <10°. Most of the pelvic and spinal parameters of patients with a large pelvic incidence were insufficiently corrected and they had an FBI index >10° CONCLUSION: PSO is a surgical procedure enabling correction of multiplane rigid spinal deformities that require major sagittal correction. It was seen to be highly effective in patients with a small or moderate pelvic incidence (PI <60°) but was sometimes less effective in patients with large pelvic incidence due to insufficient lordosis correction. Clinical results were highly correlated with the value of the FBI index.

Lumbar scoliosis associated with spinal stenosis in idiopathic and degenerative cases.

UNLABELLED: Degenerative de novo scoliosis is commonly present in older adult patients. The degenerative process including disc bulging, facet arthritis, and ligamentum flavum hypertrophy contributes to the appearance of symptoms of spinal stenosis. Idiopathic scoliosis has also degenerative changes that can lead to spinal stenosis. PURPOSE: The aetiology, prevalence, biomechanics, classification, symptomatology, and treatment of idiopathic and degenerative lumbar scoliosis in association with spinal stenosis are reviewed. STUDY DESIGN: Review study is based on a review of pertinent but non-exhaustive literature of the last 20 years in PubMed in English language. METHODS: Retrospective analysis of studies focused on all parameters concerning scoliosis associated with stenosis. RESULTS: Very few publications have focused specifically on idiopathic scoliosis and stenosis, and this was before the advent of modern segmental instrumentation. On the other hand, many papers were found for degenerative scoliosis and stenosis with treatment methods based on aetiology of spinal canal stenosis and analysis of global sagittal and frontal parameters. Satisfactory clinical results after operative treatment range from 83 to 96 % but with increased percentage of complications. Recent literature analysed the importance of stabilizing or not the spine after decompression in such situation knowing the increasing risk of instability after facet resection. No prospective randomized studies were found to support short instrumentation. Long instrumentation and fusion to prevent distabilization after decompression were always associated with higher complication rates. Imbalance patients with unsatisfactory compensation capacities were at risk of complications. CONCLUSIONS: Operative treatment using newly proposed classification system of lumbar scoliosis with associated canal stenosis is useful. Sagittal balance and rotatory dislocation are the main parameters to analyse to determine the length of fusion.

Sagittal parameters of global cervical balance using EOS imaging: normative values from a prospective cohort of asymptomatic volunteers.

OBJECTIVE: To define reference parameters for analyzing sagittal balance of the cervical spine in asymptomatic volunteers. METHODS: Prospective study after Bioethics Committee approval. Imaging performed using a low-dose radiographic system (EOS Imaging, Paris, France). The absence of pain was assessed using the Oswestry Questionnaire and VAS. 106 subjects were included of whom 55.66 % were men. The parameters measured were: pelvic incidence, pelvic tilt, sacral slope, thoracic and lumbar curvature, C7 plumb line position and the spino-sacral angle. The C7 slope and new parameters were measured: cranial incidence, defined in relation to the McGregor line and the sella turcica allowing to define cranial slope and tilt, and the spino-cranial angle (SCA). RESULTS: This study demonstrated a close correlation between the C7 slope and the cranio-cervical system. Economic sagittal balance in the asymptomatic population was defined by a constant SCA angle of 83° ± 9°. To maintain this balance, a spine with a marked C7 slope will present lordosis and vice versa. Cranial incidence is an anatomical parameter characteristic of the cranio-cervical system which makes it possible to analyze the spatial positioning of the head and to predict the desired value of cervical lordosis which is closely correlated to cranial slope. CONCLUSION: The C7 slope has a predictive value of the shape of the cervical spine in the sagittal plane. One-third of the asymptomatic population had cervical kyphosis. Our results could be used to study sagittal balance before and after arthrodesis, or cervical prosthesis.

Reproducibility and repeatability of a new computerized software for sagittal spinopelvic and scoliosis curvature radiologic measurements: Keops(®).

PURPOSE: The purpose of this study was to evaluate the inter- and intra-observer variability of the computerized radiologic measurements using Keops(®) and to determine the bias between the software and the standard paper measurement. METHODS: Four individuals measured all frontal and sagittal variables on the 30 X-rays randomly selected on two occasions (test and retest conditions). The Bland-Altman plot was used to determine the degree of agreement between the measurement on paper X-ray and the measurement using Keops(®) for all reviewers and for the two measures; the intraclass correlation coefficient (ICC) was calculated for each pair of analyses to assess interobserver reproducibility among the four reviewers for the same patient using either paper X-ray or Keops(®) measurement and finally, concordance correlation coefficient (rc) was calculated to assess intraobserver repeatability among the same reviewer for one patient between the two measure using the same method (paper or Keops(®)). RESULTS: The mean difference calculated between the two methods was minimal at -0, 4° ± 3.41° [-7.1; 6.4] for frontal measurement and 0.1° ± 3.52° [-6.7; 6.8] for sagittal measurement. Keops(®) has a better interobserver reproducibility than paper measurement for determination of the sagittal pelvic parameter (ICC = 0.9960 vs. 0.9931; p = 0.0001). It has a better intraobserver repeatability than paper for determination of Cobbs angle (rc = 0.9872 vs. 0.9808; p < 0.0001) and for pelvic parameter (rc = 0.9981 vs. 0.9953; p < 0.0001). CONCLUSIONS: We conclude that Keops(®) has no bias compared to the traditionally paper measurement, and moreover, the repeatability and the reproducibility of measurements with this method is much better than with similar standard radiologic measures done manually in both frontal and sagittal plane and that the use of this software can be recommended for clinical application. LEVEL OF EVIDENCE: Diagnostic, level III.

Insufficient restoration of lumbar lordosis and FBI index following pedicle subtraction osteotomy is an indicator of likely mechanical complication.

PURPOSE: Pedicle subtraction osteotomies (PSO) enable correction of spinal deformities but remain difficult and are associated with high complication rates. This study aimed to prospectively review different post-operative complications and mechanical problems in patients who underwent PSO as treatment for sagittal imbalance as sequelae of degenerative disc disease or previous spinal fusion. METHOD: This was a descriptive prospective single center study of 63 patients who underwent sagittal imbalance correction by PSO. Radiographic analysis of pre- and post-operative pelvic and spinal parameters was completed based on EOS images following 3D modeling. Global and sub-group analyses were completed based on the Roussouly classification. A systematic analysis of post-operative complications was conducted during hospital stay and at follow-up visits. RESULTS: Complications included 15 cases (20.2%) of bilateral leg pain, with transient neurological deficit in 6 cases (9.5%), and 9 cases (12.5%) of early surgical site infections. Intra-operative complications included five tears of the dura mater and two cases of excessive blood loss (>5,000 mL). Two mortalities occurred from major intracerebral bleeds in the early post-operative period. Mechanical complications were principally non-union (9 cases) and junctional kyphosis (3 cases). All 19 post-operative complications (28.1%) were revised at an average of 2 years following surgery. All mechanical complications were found in the patients who had insufficient imbalance correction and this was mainly associated with high PI (>60°) or a moderate PI (45-60º) combined with excess FBI pre-operatively that remained >10° post-operatively. CONCLUSION: Infection and neurologic complications following PSO are relatively common, and frequently reported in the literature. The principal cause of mechanical complications, such as non-union or junctional kyphosis, was insufficient sagittal correction, characterized by post-operative FBI >10°. The risks of insufficient correction are greater in patients with higher pelvic incidence and those patients who required very high correction.

Hemostats in Spine Surgery: Literature Review and Expert Panel Recommendations.

Bleeding in spine surgery is a common occurrence but when bleeding is uncontrolled the consequences can be severe due to the potential for spinal cord compression and damage to the central nervous system. There are many factors that influence bleeding during spine surgery including patient factors and those related to the type of surgery and the surgical approach to bleeding. There are a range of methods that can be employed to both reduce the risk of bleeding and achieve hemostasis, one of which is the adjunct use of hemostatic agents. Hemostatic agents are available in a variety of forms and materials and with considerable variation in cost, but specific evidence to support their use in spine surgery is sparse. A literature review was conducted to identify the pre-, peri-, and postsurgical considerations around bleeding in spine surgery. The review generated a set of recommendations that were discussed and ratified by a wider expert group of spine surgeons. The results are intended to provide a practical guide to the selection of hemostats for specific bleeding situations that may be encountered in spine surgery.