Degenerative Spinal Deformity Research Articles

Rapid development of minimally invasive spinal surgery: exciting advancements and challenges.

This special section of Annals of Translational Medicine focuses on the important and interesting topic of minimally invasive spinal surgery (MISS). Techniques of MISS have developed rapidly in the past few decades. The spectrum of MISS now includes spinal degenerative diseases, spinal trauma, spinal deformity and spinal tumors.

EUROSPINE 2017 FULL PAPER AWARD: Time to remove our rose-tinted spectacles: a candid appraisal of the relative success of surgery in over 4500 patients with degenerative disorders of the lumbar spine, hip or knee

Studies comparing the outcome of spine surgery with that of large-joint replacement report equivocal findings. The patient-reported outcome measures (PROMs) used in such studies are typically generic and may not be sufficiently sensitive to the successes/failures of treatment. This study compared different indices of "success" in patients undergoing surgery for degenerative disorders of the lumbar spine, hip, or knee, using a validated, multidimensional, and joint-specific PROM. Preoperatively and 12months postoperatively, 4594 patients (3937 lumbar spine, 368 hip, 269 knee) undergoing first-time surgery completed a PROM that included the Core Outcome Measures Index (COMI) for the affected joint. The latter comprises a set of single items on pain, function, symptom-specific well-being, quality of life, and disability-all in relation to the specified joint problem. Other single-item ratings of treatment success were made 12 months postoperatively. In multiple regression analyses, controlling for confounders, the mean improvement in COMI at 12months was greatest for the hip patients and lowest for those with degenerative spinal deformity (=the statistical reference group) (p<0.05). Compared with spinal deformity, the odds of achieving "success" were: higher for hip (OR 4.6; 95% CI 2.5-8.5) and knee (OR 4.0; 95% CI 2.1-7.7) (no difference between spine subgroups) for "satisfaction with care"; higher for hip (OR 16.9; 95% CI 7.3-39.6), knee (OR 6.3; 95% CI 3.4-11.6), degenerative spondylolisthesis (OR 1.6; 95% CI 1.2-2.2), and herniated disc (OR 1.7; 95% CI 1.2-2.4) for "global treatment outcome"; and higher for hip (OR 13.8; 95% CI 8.8-21.6), knee (OR 5.3; 95% CI 3.6-7.8), degenerative spondylolisthesis (OR 1.6; 95% CI 1.3-2.1), and herniated disc (1.5; 95% CI 1.1-2.0) for "patient-acceptable symptom state". Patient-rated complications were the greatest in degenerative spinal deformity (29%) and the lowest in hip (18%). The current study is the largest of its kind and the first to use a common, but joint-specific instrument to report patient-reported outcomes after surgery for degenerative disorders of the spine, hip, or knee. The findings provide a sobering account of the significantly poorer outcomes after spine surgery compared with large-joint replacement. Further work is required to hone the indications and patient selection criteria for spine surgery. The data should be used to lobby research funding-bodies, governmental agencies, industry, and charitable foundations to invest more in spine research/registries, in the hope of ultimately improving spine outcomes. These slides can be retrieved under Electronic Supplementary Material.

Comparison of clinical outcome between utilized second sacral alar-iliac and iliac screw on kyphoscoliosis patients

Objective: To compare the clinical outcome and health related quality of life(HRQoL)of patients with degenerative spinal deformity who underwent spino-pelvic fixation utilized second sacral alar-iliac(S(2)AI)with patient utilized traditional iliac screw(IS). Methods: Patients diagnosed as degenerative spinal deformity who underwent spino-pelvic fixation utilized either S(2)AI screw or Iliac screw at Department of Spine Surgery of Drum Tower hospital from January 2013 to January 2016 were retrospectively analyzed. Patients were divided into two groups according to the pelvic fixation technique. Cobb's angle, coronal balance distance(CBD), regional kyphosis(RK), sagittal vertical axis(SVA)were recorded at pre-operation, post-operation and last follow up. The MOS item short from the health survey(SF-36), visual analogue scale(VAS), Oswestry disability index(ODI) were also recorded at pre-operation and last follow up. Five physical examinations were administered to all patient at the last follow up to diagnose sacroiliac joint dysfunction, three tests resulting positive were regarded as dysfunction. Repeated measurement analysis of variance, t-test or non-parametric test was used to analyzed the data, respectively. Results: A total of 22 patients who met the inclusion were recruited in this study. Fourteen patients were utilized S(2)AI screw and 8 patients were utilized iliac screw.There were no significant differences in age, gender, follow up time between two groups. Cobb's angle, CBD, RK, SVA at pre- and post-operation and last follow up showed no significant difference between two groups.SF-36, ODI, VAS at pre-operation and last follow up showed no significant difference between two groups. Compared with baseline, Cobb's angle(44.4°±14.0° vs. 20.2°±7.2° vs. 18.3°±7.1°), C(7)PL-CSVL((25.3±16.0)mm vs. (10.3±5.7)mm vs. (9.2±4.2)mm), RK(33.0°(-12.0°, 50.0°) vs. 20.0°(-33.0°, 8.5°) vs. -19.0°(-29.0°, 19.0°)), SVA((31.5±34.4)mm vs. (12.1±8.4)mm vs. (10.9±7.2)mm), SF36-physical function summary(PCS)(39.8±14.3 vs. 68.2±21.5), SF36-mental component summary(MCS)(44.9±14.8 vs. 73.9±19.9), ODI(37.7±16.9 vs. 19.8±15.8), VAS(4.8±2.1 vs. 1.8±0.9) were significantly improved postoperatively in S(2)AI group(P<0.05). In the IS group, compared with baseline, Cobb's angle(54.3°±18.3° vs. 26.1°±13.2° vs. 25.6°±18.3°), C(7)PL-CSVL((31.0±16.0)mm vs. (13.9±7.0)mm vs. (12.4±6.6)mm), RK (47.0°(15.0°, 57.0°) vs. 4.0°(-10.0°, 16.0°) vs. 7.0°(-9.0°, 12.0°)), SVA((27.1±23.9)mm vs.(13.1±7.5)mm vs. (13.6±6.0)mm), SF36-PCS(29.7±7.1 vs. 61.1±11.2), SF36-MCS(35.9±7.1 vs. 64.0±11.1), ODI(48.6±13.4 vs. 19.0±10.7), VAS(4.9±1.8 vs. 2.6±1.3) were also significantly improved postoperatively(all P<0.05). There were two patients need revision surgery in the IS group due to the instrumentation-related complication. None of the patients in the S(2)AI group needed revision surgery. There were no instances of sacroiliac joint dysfunction in both groups at last follow up. Conclusion: Spino-pelvic fixation utilizing S(2)AI screw could provide similar correction rate to iliac screw and the sacroiliac joint penetration due to S(2)AI won't affect the HRQoL in patient with degenerative deformity who utilized S(2)AI.

MINIMALLY INVASIVE SURGICAL TREATMENT FOR ADULT DEGENERATIVE LUMBAR SCOLIOSIS

Objective. To assess the efficacy of decompression, correction, and stabilization of the lumbar spine deformity using minimally invasive techniques in patients with degenerative lumbar scoliosis. Material and Methods. A retrospective controlled two-center study included 62 patients who underwent surgery for clinical manifestations of degenerative scoliosis of the lumbar spinal canal. Results. Average Oswestry index before surgery was 69.69 %, after surgery it decreased to 33.00 % and ranged between 14 and 50 %. Average magnitude of the lumbar lordosis after surgery was 39.2°; average rate of deformity correction - 56.53 %; average magnitude of deformity reduced to 13.46° ± 6.08°. Two-fold reduction of the apical vertebra rotation was observed. Conclusion. The use of the principles of minimally invasive surgery allows to expand the indications for surgical treatment of degenerative spinal deformities and the scope of intervention, and to reduce intraoperative blood loss.

Surgical treatment of osteoporotic degenerative spinal deformity with expandable pedicle screw fixation: 2-year follow-up clinical study.

Osteoporotic bone offers poor purchase for the instrumentation in patients with degenerative spinal deformity (DSD), which could lead to several complications. Recently, augmentation methods to improve pedicle screw fixation have been proposed. This retrospective study was to investigate the clinical and radiographic outcomes of expandable pedicle screws (EPS) in patients with osteoporotic DSD. Expandable pedicle screws (EPS) provide excellent instrument fixation in patients with osteoporotic DSD, improving radiographic and clinical outcomes. A total of 27 (6 males and 21 females) DSD patients who underwent orthopedics operation with EPS were retrospectively studied. Full-length standing spinal radiographs were obtained in all patients pre- and postoperatively and again at the two-year follow-up. The functional evaluations before operation and at two-year follow-up were graded with Scoliosis Research Society outcomes instrument-22 (SRS-22) and Oswestry Disability Index (ODI) scoring system. All patients obtained good corrective outcomes on spinal deformity. The preoperative ODI score was 36.7% and reduced to 11.9% at two-year follow-up (p=0.0000). Before operation, the SRS-22 function, pain, appearance and mental scores were 2.7±0.4, 3±0.6, 2.7±0.5 and 2.9±0.6, respectively. The scores at two-year follow-up were significantly improved to 3.8±0.7, 4.2±0.6, 4.3±0.6 and 4.4±0.7, respectively (p=0.0000). The SRS-22 satisfaction score was 4.6±0.4 at two-year follow-up. No instances of screw breakage, loosening or pullout in any patient at follow-up. EPS provides excellent instrument fixation in patients with osteoporotic DSD, improving radiographic and clinical outcomes at two years' follow-up. Retrospective case series study. IV.

Revision surgery for degenerative spinal deformity: a case report and review of the literature.

Management of spinal degenerative deformities always represents a challenge for the spinal surgeon. We report a case of revision surgery for adult scoliosis, focusing of most common errors in pre-surgical management and criteria for reoperation. We analyzed the spino-pelvic parameters on the standing whole-spine X-ray and the role of sagittal balance. To restore 45° of lumbar lordosis, we performed a L3 Pedicle Subtraction Osteotomy (PSO), along with L2-L3 and L3-L4 eXtreme Lateral Interbody Fusion (XLIF). In cases of adult scoliosis, careful preoperative planning is necessary in an attempt to avoid difficult, expensive, and high-risk additional procedures.

Overpowering posterior lumbar instrumentation and fusion with hyperlordotic anterior lumbar interbody cages followed by posterior revision: a preliminary feasibility study.

OBJECTIVE The authors' aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities. METHODS The authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (< 6 levels). Preoperative and postoperative standing radiographs were evaluated to measure segmental lordosis (SL) along with standard sagittal parameters. Radiographic signs of pseudarthrosis at previously fused levels were also sought in all patients. RESULTS The average patient age was 54 years (range 30-66 years). The mean follow-up was 11.5 months (range 5-26 months). The mean SL achieved with 12°, 20°, and 30° cages was 13.1°, 19°, and 22.4°, respectively. The increase in postoperative SL at the respective surgically treated levels for 12°, 20°, and 30° cages that were used to overpower posterior instrumentation/fusion averaged 6.1° (p < 0.05), 12.5° (p < 0.05), and 17.7° (p < 0.05), respectively. No statistically significant difference was found in SL correction at levels in patients who had pseudarthrosis (n = 18) versus those who did not (n = 18). The mean overall lumbar lordosis increased from 44.3° to 59.8° (p < 0.05). In the long-construct group, the mean improvement in sagittal vertical axis was 85.5 mm (range 19-249.3 mm, p < 0.05). Endplate impaction/collapse was noted in 3 of 36 levels (8.3%). The anterior complication rate was 13.3%. No neurological complications or vascular injuries were observed. CONCLUSIONS ALIF in which hyperlordotic cages are used to overpower posterior spinal instrumentation and fusion can be expected to produce an increase in SL of a magnitude that is roughly half of the in-built cage lordotic angle. This technique may be particularly suited for lordosis correction from the front at lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.

L5/S1 anterior lumbar interbody fusion technique

Lumbar interbody fusion (LIF) is a procedure that is indicated for various spinal disorders including degenerative disc disease, instability and deformity, neoplasia, infection, and traumatic pathologies. Degenerative pathologies include discogenic lower back pain, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity, and spondylolisthesis (1). There are various approaches to LIF: anterior (ALIF), posterior (PLIF), transforaminal (TLIF), oblique (OLIF) and lateral (LLIF). The LIF involves placement of an implant device following discectomy and endplate preparation (2,3). ALIF was first described in the treatment of Pott’s disease (4), and over time, ALIF procedure has been studied extensively and is now a commonly performed procedure for degenerative lumbar spinal disease (3,5). Unlike the PLIF technique, the anterior approach does not require access through the spinal canal with retraction of the nerve roots and cauda equina. Furthermore, it spares potential iatrogenic injury to the posterior spinal muscles (2).

Minimally Invasive Scoliosis Surgery with Oblique Lateral Lumbar Interbody Fusion: Single Surgeon Feasibility Study.

BackgroundDegenerative deformities of the spine have traditionally been treated with extensive open surgeries. However, these open procedures are associated with a high degree of surgical morbidity. In this study, we explore whether clinical improvement in patients with spinal deformities can be achieved using a new minimally invasive surgery (MIS) called oblique lateral lumbar interbody fusion (OLLIF). OLLIF is a MIS single surgeon procedure in which the disc is approached through Kambin’s triangle. OLLIF can achieve correction of spinal deformities through careful cage placement.PurposeThe purpose of this study is to establish the safety and efficacy of using OLLIF to correct spinal deformities and to collect early outcome data. Collected data includes perioperative outcomes, patient reported outcomes, and radiographic outcomes.Study design/settingThis study is a retrospective review of 37 OLLIF surgeries in 36 patients with symptomatic degenerative spinal deformity. Collected perioperative data included surgery time, blood loss, and hospital stay. Follow-up was conducted at least 150 days post surgery. We recorded complications and patient reported outcomes such as Oswestry Disability Index (ODI) and pain scale. Imaging was conducted pre- and post-surgery. Fusion rates and changes in Cobb angle were also measured.ResultsA total of 37 surgeries that treated 100 vertebral levels were performed. For two and three level procedures, respectively, the mean blood loss was 83 and 178 ml, the average surgery time was 74 and 158 minutes and the average hospital stay was 2.6 and 3.3 days. The patients ambulated within 24 hours in all but two cases. The patients reported pain improvements on the ten-point pain scale from 8.3 to 3.7 (p<0.001) and on the ODI from 53% to 32%. Cobb angles decreased from 16° to 9.3° (p<0.001), amounting to 2.5° of correction per level of surgery. Detailed imaging was reviewed by independent radiologists for 24 cases and 100% interbody fusion was achieved along with 71% right posterolateral and 74% left posterolateral fusion. There were three cases of mild nerve irritation/neuropraxia and no infections.ConclusionsOLLIF is a safe and effective MIS technique to correct adult degenerative scoliosis. Unlike alternative procedures, OLLIF is technically less complex than comparable procedures and can safely be used from the thoracolumbar junction to S1.

Adult Degenerative Spinal Deformity: Overview and Open Approaches for Treatment.

Adult Degenerative Spinal Deformity: Overview and Open Approaches for Treatment.

Commentary: Appropriate Use Criteria for Lumbar Degenerative Scoliosis: Developing Evidence-based Guidance for Complex Treatment Decisions

Lumbar degenerative scoliosis is a relatively common problem, and is being treated more frequently due to the confluence of an aging population and an increased capacity and willingness to manage difficult problems in older patients. Lumbar degenerative scoliosis is a complex pathology as it often involves the intersection of degenerative spinal stenosis and spinal deformity. While previous studies provide an indication that these patients may benefit from surgical treatment, the substantial variability in treatment underscores the opportunity for improvement. Optimizing treatment for lumbar degenerative scoliosis is critical as surgical intervention, while potentially providing substantial clinical benefit also entails measurable risk and significant expense. In light of these issues, evidence-based guidance generated through Appropriate Use Criteria (AUC) development offers the potential to improve both the quality and cost effectiveness of care.The lumbar degenerative scoliosis AUC represents a significant step toward evidence-based treatment in spinal surgery. This is the first time that spine societies and industry partners have collaborated to support evidence development. The willingness of all involved to support a completely independent process underlines a commitment to trust the evidence. Subsequent studies may validate and/or refine the AUC recommendations, but the most important result is that the standard for evidence quality has been raised.

Trends in the use of patient-reported outcome instruments in neurosurgical adult thoracolumbar deformity and degenerative disease literature.

Objective:Shifting national healthcare trends place increased emphasis on patient-centered care and value-based outcomes, and thus, patient-reported outcome instruments (PROIs) are often used. We sought to characterize the trends in PROI use over the past decade with regard to thoracolumbar degenerative spine disease and spinal deformity in major neurosurgical journals.Methods:Articles were screened for PROI use through a PubMed search among five major neurosurgical journals from 2006 to 2016. Articles focusing on adult thoracolumbar deformity and degenerative disease were selected with stringent criteria to further characterize PROI use.Results:A total of 29 different PROIs were used among 102 articles identified from 2006 to 2016 using our search strategy. Journal of Neurosurgery: Spine contained the most articles utilizing PROIs with 35.3% of all articles meeting search criteria. The most frequently used PROIs were Oswestry Disability Index, visual analog scale, and the European Quality of Life Five-dimension questionnaire used in 79.4%, 59.8%, and 29.4% of articles, respectively. Linear regression identified a significant increase in the number of articles employing PROIs from 2006 to 2016 (Y = 1.85, R2= 0.77, P < 0.01). The total number of PROIs per article was relatively stagnant over time and did not significantly change (Y = 0.03, R2= 0.05, P = 0.51).Conclusions:PROI use as an outcome tool in the adult thoracolumbar disease literature has increased during the past decade, which may be an indicative of PROI use to define patient expectations. This may also represent a trend toward PROI use as a surrogate measure of value-based care.

Long fusion correction of degenerative adult spinal deformity and the selection of the upper or lower thoracic region as the site of proximal instrumentation: a systematic review and meta-analysis

ObjectiveThe aim of this study was to compare outcomes when the upper and lower thoracic regions were used as the site of proximal instrumentation to treat adult spinal deformity.MethodsMEDLINE, Embase...

Role of minimally invasive surgery for adult spinal deformity in preventing complications.

With the aging population, there is a rising prevalence of degenerative spinal deformity and need of surgical care for these patients. Surgical treatment for adult spinal deformity (ASD) is often fraught with a high rate of complications. Minimally invasive surgery (MIS) has for the past decade been adopted by spine surgeons to treat ASD in the hopes of reducing access-related morbidity and perioperative complications. The benefits of MIS approach in general and recent development of MIS techniques to avoid long-term complications such as pseudoarthrosis or proximal junctional kyphosis are reviewed.

Anterior hyperlordotic cages: early experience and radiographic results.

OBJECTIVE The aim of this study was to evaluate the segmental correction obtained from 20° and 30° hyperlordotic cages (HLCs) used for anterior lumbar interbody fusion in staged anterior and posterior fusion in adults with degenerative spinal pathology and/or spinal deformities. METHODS The authors report a retrospective case series of 69 HLCs in 41 patients with adult degenerative spine disease and/or deformities who underwent staged anterior, followed by posterior, instrumentation and fusion. There were 29 females and 12 males with a mean age of 55 years (range 23-76 years). The average follow-up was 10 months (range 2-28 months). Radiographic measurements of segmental lordosis and standard sagittal parameters were obtained on pre- and postoperative radiographs. Implant subsidence was measured at the final postoperative follow-up. RESULTS For 30° HLCs, the mean segmental lordosis achieved was 29° (range 26°-34°), but in the presence of spondylolisthesis this was reduced to 19° (range 12°-21°) (p < 0.01). For 20° HLCs, the mean segmental lordosis achieved was 19° (range 16°-22°). The overall mean lumbar lordosis increased from 39° to 59° (p < 0.01). The mean sagittal vertical axis (SVA) reduced from 113 mm (range 38-320 mm) to 43 mm (range -13 to 112 mm). Six cages (9%) displayed a loss of segmental lordosis during follow-up. The mean loss of segmental lordosis was 4.5° (range 3°-10°). A total complication rate of 20% with a 4.1% transient neurological complication rate was observed. The mean blood loss per patient was 240 ml (range 50-900 ml). CONCLUSIONS HLCs provide a reliable and stable degree of segmental lordosis correction. A 30° HLC will produce correction of a similar magnitude to a pedicle subtraction osteotomy, but with a lower complication rate and less blood loss.

Operative Management of Post-tumor Spinal Deformity

Introduction The purpose of our research is evaluation of the outcome after surgery and health-related quality of life (HRQOL) parameters in patients with post-tumor spinal deformity. Material and Methods Retrospective clinical and radiographic data were collected for 33 patients (15 male and 18 female, average age of 61.4 years) with spinopelvic malalignments (SRS-Schwab sagittal modifiers: 2 grade and more) who underwent spinal deformity surgery. Patients were divided into two groups. The first group included 13 patients ( n = 12 after chemotherapy of plasmacytoma, n = 1 patient after radiotherapy of cervix uteri cancer metastasis) with confirmed spinal oncology diagnosis by biopsy. All patients have had oncology remission with a 3-year minimum follow-up. Spinal deformity was developed in the period between 1 and 6 years after conservative treatment. Repeated biopsy did not show tumor cells, this was evaluated as local control of tumor. Low scores of HRQOL and unsuccessful nonoperative approach were indications for surgical intervention. The second comparative group consisted of 20 patients with “de novo” degenerative or posttraumatic spinal deformity. The aim of surgical management was to achieve sagittal balance, using osteotomies and transpedicular instrumentalization. Groups were evaluated with HRQOL-scales including VAS, ODI, SF36 and SRS-24. Radiographical assessment included Cobb coronal angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), sagittal vertical axis (SVA). Radiographical, HRQOL-parameters and complications were analyzed and compared between two groups. The comparisons were done by using independent sample Student t-test. A p-value of less than 0.05 was accepted as significant. Results Both groups showed a restoration of global spinal alignments without significant differences in TK, LL, PI, PT, SS, SVA parameters (p &gt; 0.05). In addition, HRQOL-scores (VAS, ODI, SF36, SRS-24) of the patients were increased after operation. The HRQOL-scores after 2 years are slightly higher in the first group, but we did not get significant difference between groups (p &gt; 0.05). The number of complications in the form of implant instability, proximal and distal junctional disorders was comparable (p &gt; 0.05). However, general medical complications in the first group was significantly higher than in the second one ( p &lt; 0.05). It is important that no patients had local recurrence or metastasis of tumor during follow-up in the first group. Conclusion Spinal tumor under local control is not contraindication for spinal deformity surgery. Realigning of the sagittal plane is paramount, especially because of the sagittal balance impact on quality of life.

Technology of pre-operative digitalized simulation of osteotomy in degenerative spinal deformity with sagittal malalignment

Objective To assess the availability of applying pre-operative digitalized simulation of osteotomy in degenerative scoliosis by comparing the sagittal parameters of pre-operative simulation and post-operative results. Methods A retrospective study of 16 degenerative scoliosis patients who underwent posterior PSO surgeries in our center from June 2012 to June 2014, 15 cases (2 male and 13 female) of which successfully underwent pre-operative digitalized simulation of osteotomy. Long-cassette standing upright posterior-anterior and lateral radiographs of the spine and pelvis were taken before and two weeks after surgery. The sagittal radiographic parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA) were measured. PT setting method and ratio control method were used in pre-operative lateral radiographs for digital design of osteotomy, and the sagittal parameters were measured after osteotomy simulation. Pared-samples t test was conducted to assess difference in terms of sagittal parameters between the 2 methods of osteotomy simulation and post-operative results. Results LL was 43.33°±12.55° according to PT setting method and 40.67°±6.79° based on ratio control method, both of which showed no significant difference compared to actual post-operative LL (34.16°±8.52°). Regarding SVA, significant difference was observed between ratio control method (-24.78±31.44) mm and actual post-operative value (13.38±37.83) mm. Smaller PT was found as a result of PT setting method (11.33°±0.47°) compared to that of post-operative result vs. (20.33°±5.37°) while similar PT was simulated by ratio control method. Conclusion The present study confirmed that the pre-operative digital simulation of osteotomy can predict post-operative sagittal restoration. The combination of PT setting method and ratio control method may be a better solution for simulation. Meanwhile, the angle of osteotomy, the close ratio, and the thoracic kyphosis compensation should be taken into consideration during simulation. Key words: Preoperative period; Osteotomy; Scoliosis; Signal processing, computer-assisted

Analysis of the reliability of surgeons' ability to differentiate between idiopathic and degenerative spinal deformity in adults radiologically. What descriptive parameters help them decide?

Adult spinal deformity (ASD) may be classified as idiopathic (ID) or degenerative (DD) (or other) based on classifier's perception, the reliability of and factors inherent to which remain unknown. The aim of this study is to evaluate the inter- and intra-observer reliability of surgeons' perception in differentiating ID from DD and to identify the determinants of this differentiation. From a multicentric prospective database of ASD, 179 patients were identified with the diagnosis of ID (n=103) or DD (n=76); without previous surgery; and a lumbar coronal curve larger than 20°. Standing antero-posterior and lateral X-rays of these patients were sent to five experienced spine surgeons to be identified as DD or ID (or other); followed by a second round after reshuffling. Weighted kappa statistics were used, the strength of agreement for the kappa coefficient was considered as; 0.81-1=almost perfect, 0.61-0.8=substantial, 0.41-0.60=moderate, 0.21-0.40=fair, 0.01-0.20=slight, and≤0=poor. Patients were then stratified based on the number of agreements on a total of 10 rounds as excellent (10 out of 10), good (more than 7 out of 10) and fair/poor (7 and less). These excellent and good agreements were further compared for additional radiological parameters. Agreement levels were moderate to substantial for intra but mostly fair for inter-observer comparisons. For ID patients, there were 42 cases with excellent and 38 with very good agreement whereas for DD, there were no excellent and only 17 cases with very good agreement. Upon comparison of these (ID vs DD for at least very good cases), it was seen that they were different for some coronal parameters such as lumbar Cobb angle (larger in ID, p<0.001), central sacral vertical line (CSVL) modifier (C more common in ID, p=0.007) and presence of rotatory subluxation (less common in DD, p=0.017), but very different for sagittal parameters (lumbar lordosis, sagittal vertical axis, T2 sagittal tilt, pelvic tilt, sacral slope, and global tilt; increased sagittal imbalance in DD, all p≤0.001). Surgeons in this study demonstrated reasonable (moderate to substantial) intra-observer agreement, but only fair agreement amongst them. Alarming as it may appear, we should be cautious in interpreting these results based on only radiology and no clinical information. In patients with good agreement, the most consistent radiologic determinant of degenerative ASD appeared to be the presence of sagittal imbalance.

Video-Assisted Anterior Retroperitoneal Approach to the Lumbar Spine. A Minimal Invasive Technique Improved by the Use of Endoscopic Camera to Treat Lumbar Spine Diseases

The anterior retroperitoneal approach is a technique to treat disc degenerative disease (DDD), spinal deformities, traumas, tumors and infections. It can be used to perform Anterior Lumbar Interbody Fusions (ALIF) or Total Disc Replacements (TDR). Though being a fast procedure that is becoming more often used by spinal surgeons, the anterior approach requires an adequate knowledge of the anatomy of the abdomen to lessen the risks of intraoperative complications. The authors’ preferred technique is the left retroperitoneal video-assisted approach, using an endoscope to visualize and magnify the deep anatomical structures, discectomy procedure and hardware implant. In a review of our casuistry from 2010 to 2012, 163 patients underwent an anterior lumbar approach, and 139 of these had a single L4-5 or L5-S1 level treatment. A 3.6% rate of global complications (1.44% of major vascular injuries) has been observed, with a mean operation time of 116.4 minutes and a mean blood loss of 156.1 ml. These values show how the anterior retroperitoneal video-assisted approach for the treatment of lumbar diseases is a fast procedure that implies low blood loss, with a low rate of intraoperative complications.

Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF.

Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications. In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines for the indications for interbody fusion options. Thirdly, this article provides a description of each approach, and illustrates the potential benefits and disadvantages of each technique with reference to indication and spine level performed.