Sagittal Correction Research Articles

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

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 2years and demonstrate the benefit of sub-group analysis as a function of pelvic incidence (PI). 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. 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 +9cm before surgery to +4.3cm 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° 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.

Single and Multiple Level One Stage Posterior Hemivertebrectomy and Short Segment Fixation: Experience with 22 Cases and Comparison of Single vs. Multilevel Procedures with Minimum 2-Year Follow-Up

Study DesignData of 22 patients with congenital scoliosis who underwent single stage posterior hemivertebrectomies and short segment fixation with a minimum follow-up of 2 years in our centre were studied retrospectively.PurposeTo report the efficacy of posterior hemivertebrectomy in single vs multiple level hemivertebra and compare their results.Overview of LiteratureSingle stage hemivertebrectomy is a standard procedure for single level hemivertebra. Results of multiple level hemivertebrectomies have not been reported.MethodsTwenty-two patients (9 male and 13 female) with the mean age of 11.2 years (range, 2 years 4 months to 24 years 10 months) and a mean follow up of 32 months (range, 4 to 73 months) were studied retrospectively and their results were compared.ResultsAverage number of hemivertebrae removed was 1.46 (range, 1 to 3). Mean preoperative and postoperative coronal cob angle was 48.7° (range, 22° to 80°) and 24.2° (range, 7° to 41°), respectively (p<0.001). Mean preoperative and postoperative sagittal cobb angle was 32.1° (range, 7° to 76°) and 13.6° (range, 0° to 23°), respectively (p<0.005). Mean coronal and sagittal cob correction percentage achieved was 50.2% and 51.8% respectively. Mean follow-up was 49 months (range, 30 to 84 months). Mean loss of coronal and sagittal correction at final follow-up was 4% (0% to 13.6%) degrees and 3.5% (0% to 20%), respectively.ConclusionsPosterior hemivertebrectomy in congenital scoliosis is a safe treatment option for up to 3-level hemivertebrae. Excision of thoracolumbar hemivertebrae results in better correction than thoracic and lumbar hemivertebrae.

Multidisciplinary Approach for Correction of Obstructive Sleep Apnea

ABSTRACTObstructive sleep apnea (OSA) is the most common type of sleep apnea and is caused by complete or partial obstructions of the upper airway. In this study we are presenting a case report of 11-year-old male patient with enlarged adenoids and tonsils, convex profile, receded chin, lower lip trap, class II skeletal and dental relationship with increased overjet. Surgical removal of enlarged adenoids was done before commencement of twinblock therapy. After this, two-step advancement with expansion in both arches utilizing twin blocks was planned. Four months into the treatment, patient reported with history of facial trauma with avulsed maxillary left central incisor. Twin block was then modified with pontic as replacement for maxillary left central incisor. Sagittal correction resulting in class I molar relationship was achieved in next 6 months. Fixed appliance therapy was followed. The design of the appliance and the results achieved after the postfunctional therapy are presented in this case report.How to cite this articleMadhaswar AB, Ravindranath VK, Daga PN. Multidisciplinary Approach for Correction of Obstructive Sleep Apnea. J Contemp Dent 2016;6(3):189-193.

Short to Mid-Term Term Surgical Outcome Study with Posterior Only Approach on Tuberculous Spondylodiscitis in an Elderly Population.

Study DesignRetrospective study.PurposeTo study short to mid-term outcome of surgically managed elderly patients of tuberculous spondylodiscitis with posterior only approach in terms of decision making and challenges in treatment, choice of implants and outcomes.Overview of LiteratureTuberculous spondylodiscitis in the elderly is increasing due to longer survival rates. It presents with varied clinical manifestations needing surgical management. Management in tuberculous spondylodiscitis has been scarcely reported in the elderly, with a paucity of data on the choice of implants and approach.MethodsSixteen patients (five males, 11 females) older than 70-years-of-age culture and/or histopathology proven tuberculous spondylodiscitis were included in the study. All patients were operated using a single posterior approach. Pedicle screw with rods (PS/rods) or spinal loop with sublaminar wires (SL/SLW) were used for fixation. Clinical and surgical details were recorded. Sagittal correction achieved postoperatively and loss of correction at follow-up were noted.ResultsThe mean age was 73.6 years (range, 70 to 80 years). The mean follow up was 44.5 months (range, 24 to 84 months). The mean immediate postoperative correction of sagittal deformity was 11.3 degrees; this correction was lost by a mean of 3.1 degrees at last follow-up. All 10 patients with deficit showed neurological recovery and all but one of the seven non-walkers were capable of independent ambulation at follow-up. Patients with SL/SLW and PS/rods had similar radiological outcome at final follow up.ConclusionsOperative management gives satisfactory results in elderly patients with tuberculous spondylodiscitis. The posterior approach provides adequate exposure for decompression and rigid fixation, providing satisfactory clinical and radiological outcomes. SSL/SLW and pedicle screw rod construct both give similar radiological results if used appropriately in patients.

The effect of metal density in thoracic adolescent idiopathic scoliosis.

Determine impact of metal density on curve correction and costs in thoracic adolescent idiopathic scoliosis (AIS). Ascertain if increased metal density is required for larger or stiffer curves. Multicentre retrospective case series of patients with Lenke 1-2 AIS treated with single-stage posterior only surgery using a standardized surgical technique; constructs using >80% screws with variable metal density. All cases had >2-year follow up. Outcomes measures included coronal and sagittal radiographic outcomes, metal density (number of instrumented pedicles vs total available), fusion length and cost. 106 cases included 94 female. 78 Lenke 1. Mean age 14years (9-26). Mean main thoracic (MT) Cobb angle 63° corrected to 22° (66%). No significant correlations were present between metal density and: (a) coronal curve correction rates of the MT (r=0.13, p=0.19); (b) lumbar curve frontal correction (r=-0.15, p=0.12); (c) correction index in MT curve (r=-0.10, p=0.32); and (d) correction index in lumbar curve (r=0.11, p=0.28). Metal density was not correlated with change in thoracic kyphosis (r=0.22, p=0.04) or lumbosacral lordosis (r=0.27, p=0.01). Longer fusions were associated with greater loss of thoracic kyphosis (r=-0.31, p=0.003). Groups differing by preoperative curve size and stiffness had comparable corrections with similar metal density. The pedicle screw cost represented 21-29% of overall cost of inpatient treatment depending on metal density. Metal density affects cost but not the coronal and sagittal correction of thoracic AIS. Neither larger nor stiffer curves necessitate high metal density.

Comparation in outcome of long segment fusion versus short segment fusion for the treatment of adult degenerative scoliosis

Objective To investigate the effect of decompression with long-segment (L) or short-segment (S) fusion on the outcomes of the surgical treatment for degenerative adult scoliosis (ADS) patiens. Methods A retrospective study on 32 patients treated in our department for ADS from April 2013 to May 2015 was carried out, including 12 male and 20 female (1∶1.7). Their average age was 66.4 (range: 51-77 years). All patients underwent decompression and fusion surgeries through posterior approach. They were divided into long-segment fusion group (L) and short-segment fusion group (S) according to fusion range. During follow-ups (FU), clinical outcomes were assessed by means of visual analog scale (VAS) and Oswestry disability index (ODI). Radiographic evaluation on full-length standing film included coronal Cobb's angle, distant between C7 plumb line and center sacral vertical line (C7PL-CSVL), thoracic kyphosis(TK) angle, lumbar lordosis (LL) angle, pelvic incidence (PI), and pelvic tilt (PT), PI-LL, sagittal vertical axis(SVA). Postoperative complications were also recorded. Results All patients were followed up for average 2.2 years (range: 1.5-3.5 years). No significant difference of age or gender was found between two groups (L: 22, S: 10) of patients (P=0.066, 0.182). As for the fusion segments, group L (6.3±1.5) was more than group S (2.9±0.3) (P=0.001). Operation time and blood loss of group L were statistically more than group S (P 0.05); at the final FU, group L's ODI showed better functional recovery than group S's〔(12.8±9.3)% vs.(25.4±11.4)%, P 0.05), coronal Cobb's angle corrected more satisfactional in group L than group S (P<0.05). The same situation was found in C7-CSVL correction in two goup in FU (P<0.05). Sagital balance was restored to normal alignment better in group L than group S, with increase of lumbar lordosis after surgery. The overall incidence of postoperative complications was 31.3%, including wound infection, cerebrospinal fluid leakage, transient neurological symptoms and internal fixed rod breakage, more common in group L than group S. Conclusions Decompression and fusion with internal fixation showed good clinical outcomes in the treatment of ADS. Long-segment fusion yielded better coronal and sagittal correction outcomes with higher peri-operation risks; however, short-segment fusion showed higher safety with relatively inferior correction effect. Appropriate fusion mode should be chose according to the patient's deformity features. Key words: Scoliosis; Spinal fusion; Internal fixators

The effectiveness of selective thoracic fusion for treating adolescent idiopathic scoliosis: a systematic review protocol.

REVIEW QUESTION / OBJECTIVE The objective of this review is to assess the effectiveness of selective thoracic fusion as a form of treatment in adolescent idiopathic scoliosis. This will be compared with all other forms of operative management for major structural thoracic curves. INCLUSION CRITERIA Types of participants A comprehensive and exhaustive literature search will be conducted for studies that include children aged 10-18 years with adolescent idiopathic scoliosis who have a scoliosis curve with a thoracic component that is described as structural (as described by the Lenke classification). In addition those with congenital, neuromuscular or syndromic causes for their scoliosis or any previous spinal fusion will be excluded. Types of intervention This review will consider studies that evaluate fusion of the thoracic curve with distal fusion no lower than L1. Both anterior and posterior approaches will be included; however any patient who receives both will be excluded. All forms of instrumentation for fusion such as pedicle screws, hooks and rods will be included. This will be compared where possible to any other surgical fusion for a structural thoracic curve. This will include studies that compare selective and non-selective spinal fusion in the same article, or selective spinal fusion only, but not non-selective spinal fusion only. Types of outcomes Primary outcomes include: Functional/Quality of life survey (SRS- 22, SRS-24, SRS-30 or similar). Complication rate – including, but not limited to, adding on, coronal imbalance, junctional kyphosis and re-operation. Respiratory function. Secondary outcomes include: Postoperative main thoracic Cobb angle, and average change in angle. Postoperative compensatory lumbar Cobb angle, and average change in angle. Coronal balance. Sagittal balance. Apical vertebral rotation and change.

A Critical Analysis of Sagittal Plane Deformity Correction with Minimally Invasive Adult Spinal Deformity Surgery: A Two-Year Follow-Up Study

A Critical Analysis of Sagittal Plane Deformity Correction with Minimally Invasive Adult Spinal Deformity Surgery: A Two-Year Follow-Up Study

The likelihood of reaching minimum clinically important difference and substantial clinical benefit at 2 years following a 3-column osteotomy: analysis of 140 patients.

Three-column osteotomies (3COs) are technically challenging techniques for correcting severe rigid spinal deformities. The impact of these interventions on outcomes reaching minimum clinically important difference (MCID) or substantial clinical benefit (SCB) is unclear. The objective of this study was to determine the rates of MCID and SCB in standard health-related quality of life (HRQOL) measures after 3COs in patients with adult spinal deformity (ASD). The impacts of location of the uppermost instrumented vertebra (UIV) on clinical outcomes and of maintenance on sagittal correction at 2 years postoperatively were also examined. The authors conducted a retrospective multicenter analysis of the records from adult patients who underwent 3CO with complete 2-year radiographic and clinical follow-ups. Cases were categorized according to established radiographic thresholds for pelvic tilt (> 22°), sagittal vertical axis (> 4.7 cm), and the mismatch between pelvic incidence and lumbar lordosis (> 11°). The cases were also analyzed on the basis of a UIV in the upper thoracic (T1-6) or thoracolumbar (T9-L1) region. Patient-reported outcome measures evaluated preoperatively and 2 years postoperatively included Oswestry Disability Index (ODI) scores, the Physical Component Summary and Mental Component Summary (MCS) scores of the 36-Item Short Form Health Survey, and Scoliosis Research Society-22 questionnaire (SRS-22) scores. The percentages of patients whose outcomes for these measures met MCID and SCB were compared among the groups. Data from 140 patients (101 women and 39 men) were included in the analysis; the average patient age was 57.3 ± 12.4 years (range 20-82 years). Of these patients, 94 had undergone only pedicle subtraction osteotomy (PSO) and 42 only vertebral column resection (VCR); 113 patients had a UIV in the upper thoracic (n = 63) orthoracolumbar region (n = 50). On average, 2 years postoperatively the patients had significantly improved in all HRQOL measures except the MCS score. For the entire patient cohort, the improvements ranged from 57.6% for the SRS-22 pain score MCID to 24.4% for the ODI score SCB. For patients undergoing PSO or VCR, the likelihood of their outcomes reaching MCID or SCB ranged from 24.3% to 62.3% and from 16.2% to 47.8%, respectively. The SRS-22 self-image score of patients who had a UIV in the upper thoracic region reached MCID significantly more than that of patients who had a UIV in the thoracolumbar region (70.6% vs 41.9%, p = 0.0281). All other outcomes were similar for UIVs of upper thoracic and thoracolumbar regions. Comparison of patients whose spines were above or below the radiographic thresholds associated with disability indicated similar rates of meeting MCID and SCB for HRQOL at the 2-year follow-up. Outcomes for patients having UIVs in the upper thoracic region were no more likely to meet MCID or SCB than for those having UIVs in the thoracolumbar region, except for the MCID in the SRS-22 self-image measure. The HRQOL outcomes in patients who had optimal sagittal correction according to radiographic thresholds determined preoperatively were not significantly more likely to reach MCID or SCB at the 2-year follow-up. Future work needs to determine whether the Schwab preoperative radiographic thresholds for severe disability apply in postoperative settings.

Sagittal Deformity Correction during the Lateral Transpsoas Approach with Hyperlordotic Interbody Grafting, Adjunctive ALL Release, and Subsequent Smith–Peterson Osteotomy

Introduction Traditionally, surgical intervention for patients with thoracolumbar sagittal imbalance relied on posterior column shortening techniques such as the Smith–Peterson osteotomy (SPO) and pedicle subtraction osteotomy (PSO). The lateral retroperitoneal, transpsoas approach has been proven to afford significant coronal deformity correction; however, the evidence for its use in the sagittal deformity correction is less robust. Recently, the use of hyperlordotic grafts has provided all the benefits of the transpsoas approach while also allowing for sagittal deformity correction. Hyperlordotic interbody grafts and a subsequent SPO can theoretically provide a similar sagittal correction as provided by a PSO or multiple SPOs while minimizing the associated morbidities. Materials and Methods This is a retrospective review examining the preoperative and postoperative segmental lordosis after placement of a hyperlordotic cage and subsequent SPO. A total of 22 patient charts were reviewed. The mean patient age was 58.6. There were 8 males and 14 females. A 20-degree hyperlordotic cage was utilized at four intervertebral levels. The 30-degree cage was used at 19 levels. The surgical procedure involved the release of the anterior longitudinal ligament and placement of a hyperlordotic graft (NuVasive CoRoent XL-Hyperlordotic) via the lateral, retroperitoneal, transpsoas approach followed by posterior instrumentation and SPO at that level. In each instance, the hyperlordotic graft and subsequent SPO were part of a large, multilevel deformity correction and were not simply performed as a standalone procedure. Results Hyperlordotic cages were placed from T12–L1 to L4–L5 in this series. A total of 10 cages were placed at the L3–L4 interspace. The mean preoperative lordosis was 0.4 and 4.2 degrees in the 20 and 30-degree cohorts, respectively. The mean postoperative, segmental lordosis was 23.0 and 28.2 degrees in the two groups, yielding a mean correction of 22.6 degrees with the 20-degree cage and 24.0 degrees with the 30-degree cage. The 30-degree cage yielded a sagittal correction of 8.5 to 54.0 degrees. A correction of greater than 30 degrees was achieved in five cases. The single case with less than 10 degrees of lordosis restoration resulted from graft subsidence. The greatest increase in lordosis occurred in patients with the most significant preoperative segmental kyphosis. Conclusion Segmental lordosis increase of approximately 20 to 25 degrees can be expected with the placement of either a 20- or 30-degree hyperlordotic cage via the transpsoas approach with subsequent SPO at that level. This hybrid approach provides a degree of correction similar to a PSO without the associated morbidity.

Natural Evolution of Syrinx in Patients Undergoing Posterior Correction for Scoliosis Secondary to Syringomyelia

Introduction While correction surgery for syringomyelia-associated scoliosis frequently results in an elongation of the spine and may potentially influence the natural history of syringomyelia, a paucity of data exists regarding the syrinx behavior in the postoperative course. This study aims to investigate the natural evolution of syrinx in patients undergoing one-stage posterior instrumented spinal fusion for treatment of scoliosis secondary to idiopathic syringomyelia (IS). Materials and Methods Twenty-two patients with IS-associated scoliosis treated with one-stage posterior correction and fusion were evaluated at a minimum of 12-month follow-up (mean, 28.5 months; range, 12–57 months). Standing anteroposterior and lateral radiographs were examined for curve pattern, primary curve magnitude, thoracic kyphosis, and postoperative correction. Preoperatively and at follow-up, T2-weighted MR images, location, configuration, and size of the syrinx cavity were systematically assessed, and significant syrinx resolution was defined as more than 20% decrease in length or maximal syrinx/cord ratio. Results The series consisted of 15 male and 7 female patients with a mean age of 19.0 years (range, 12–35 years). Postoperative percent correction of the primary curve averaged to 64.0 ± 15.7% and was well maintained (58.5 ± 11.5%) at latest evaluation. Regarding syrinx size, the maximal syrinx/cord ratio improved from 0.44 to 0.41, with an average change rate of 3.5%. Overall, 10 (45.5%) and 11 (50.0%) patients met the criteria for syrinx improvement and stabilization, and syrinx deterioration was observed only in 1 case (4.5%). Age, gender, preoperative syrinx length, and number of fused vertebra were not associated with the prognosis of syringomyelia ( p &gt; 0.05), whereas a significantly greater coronal correction was found in patients harboring a collapsed syrinx than in those with syrinx deterioration or stabilization (73.9 vs. 54.6%, p = 0.001). Using Spearman correlation test, improvement rate of the maximal syrinx/cord ratio was found to be strongly related to the coronal percent correction of the primary curve (r = − 0.547, p = 0.008). There were no neurological or other major complications related to the surgery. Conclusion For treatment of scoliosis secondary to IS in the setting of minimal neurological deficits, one-stage spinal fusion with lengthening of the vertebral column provides an effective coronal and sagittal correction without neurological complications. Following surgery, the vast majority (95.5%) of syringes shrank or remained stable, indicating that deformity correction did not exert a deleterious effect on the natural evolution of syringomyelia.

Implant Instability, Proximal Fractures, Quality of Life, and Outcomes of Global Spinal Alignments Correction using Short Fusion in Adults and Elderly

Introduction The purpose of our research is studying of incidence of implant instability, proximal fractures of instrumented and adjacent vertebras, and evaluation of health-related quality of life (HRQOL) parameters depending on extent of the sagittal balance correction after short fusion using a posterior approach. Patients and Methods A study of 83 patients with Type L (SRS-Schwab) deformity, operated in our institute was held in the period between 2008 and 2011. Patients were divided into two groups. The first retrospective group included 43 patients who underwent short fusion of lumbar curve from T12 or L1 to L5. The second prospective group consisted of 40 patients, which were treated using short fusion from T9 to S1 extending to the pelvis. 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 with a 3-year minimum follow-up 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 In the first group the ideal sagittal balance was not achieved. The second group showed a better restoration of global spinal alignments compared with the first one ( p &lt; 0.05). The HRQOL-scores (VAS, ODI, SF36, and SRS-24) of the patients after 3 years are slightly higher in the second group, but we did not get significant difference between groups ( p &gt; 0.05). In the first group the number of complications in the form of implant instability ( n = 15, 35%) consists of loosening of screws at the end of fusion (T12/L1 or L4/5). The second group was obtained by a higher number of patients with complications ( n = 25, 63%) including loosening of screws at pelvis ( n = 15, 37.5%), proximal fractures of upper instrumented vertebra ( n = 7, 17.5%) and upper adjacent vertebra ( n = 8, 20%). Incidence of implant instability and proximal fractures in the second group was statistically more frequent ( p &lt; 0.05). Conclusion The research showed that short fusion extending to the pelvis provided good sagittal balance, global spinal alignments, and likely HRQOL-parameters after 3 years follow-up. But, eventually, we obtained higher number of complications.

Successful Correction of Sagittal Imbalance can be Calculated on the Basis of Pelvic Incidence and Age

Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several methods of preoperative calculation for sagittal correction have been proposed, most of them geometrical. A nongeometrical method, based on data of spinopelvic relationships in normal subjects, that uses the patient's pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this nongeometrical method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Materials and Methods A retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms (method a: LL = −[32.56 + PI × 0.54], method b: LL = −[PI + 10 degrees]); in both TK = PI/r (see text for definitions) obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA &lt; 50 mm and PT &lt; 20 degrees) achieved or not. Two × two tables are built and odds ratio, sensitivity and specificity and PPV/NPV are calculated for each planning method. Different levels of tolerance for undercorrection are analyzed to refine the use of the method. Results Of the 50 patients included in the study, 23 presented satisfactory alignment postoperatively. With a tolerance of hypocorrection of 10 degrees (LL) and 30 degrees (TK), correction target was achieved in 23 patients according to method a (S = 0.89, Sp = 0.87%, OR = 53.33 [95% CI: 9.677–293.931]; p &lt; 0.001), 23 patients according to method b (S = 0.93, Sp = 0.91, OR = 131.25 [95% CI:17–1013]; p &lt; 0.001). The best prediction of satisfactory alignment was obtained with method b and tolerance 0 degrees (LL) and 10 degrees (TK). All patients with complete correction of LL (both methods) achieved good alignment. Overall, 22 of the 24 (91%) patients with less than 10 degrees of undercorrection of LL (method b) achieved good alignment. Conclusion Calculation of the target lordosis based only in the value of PI and age is a reliable method that can predict good outcomes in terms of alignment. The rule LL = −(PI + 10 degrees) is an easy to calculate and very effective method of planning for lumbar lordosis and good alignment can be expected with high confidence when the final lordosis is within 10 degree of undercorrection. Including TK in surgical planning can improve the results in terms of restoration of the less known “spinopelvic balance” parameter.

Magnitude, Location, and Factors Related to Regional and Global Correction Loss in Long Adult Deformity Constructs: Report of 183 Patients with 2-Year Follow-Up

Introduction Adult deformity patients (pts) have previously been shown to lose spino-pelvic correction over time especially in the sagittal plane. The goal of this study was to analyze the source of this correction loss and specifically to quantitate the change that occurs in fused verses unfused segments. Variables examined include presence of interbody fusion, rod diameter, rod material, age, and pre-op sagittal alignment. Materials and Methods A retrospective review of a multicenter, prospective ASD database was conducted. Inclusion criteria were age ≥ 18 years, ASD, no revisions between &gt; 6 weeks and &lt; 2 years postop. Spinal pelvic parameters, thoracic kyphosis (TK:T2–T12) and lumbar lordosis (LL:L1–S1) were both measured overall as well as within and outside the instrumented segments. Overall, SVA, PT, Pi-LL change, and TK and LL change between 6 weeks and 2 years post-op was calculated. Of these pts, the amount of TH loss and TL loss within and outside of the instrumented segments was also determined as well as a percentage of the total loss for each region. Results A total of 183 pts met criteria. Between 6 weeks and 2 years post-op 61.7% of pts lost SVA (4.4 ± 4.3 cm), 65.0% lost PT (4.7 ± 4.0 deg), and 40.4% lost PI–LL (16.2 ± 9.3 deg). Overall, 63.9% had TH loss (8.0 ± 8.9 deg) and 56.8% had LL loss (5.8 ± 4.5 deg). Overall, 41.5% lost &gt; 2 cm SVA. Of the pts with &gt; 2 cm SVA loss, 60.5% had LL loss, and of those, 82.6% was within instrumented segments. Of the pts with LL loss, 13.8% had &gt; 10 deg loss. Pts with an interbody fusion have a 2.3 times ( p = 0.0076) likelihood of having any LL loss, but the interbody fusion was protective against &gt; 10 deg change (7.1%). Pts ≥ 65 years' old are 9.4 times ( p &lt; 0.0001) more likely to have LL loss than pts ≤ 45 years' old (4.4%). Pts with pre-op C7 SVA &gt; 5 cm are 2.4 times ( p = 0.0035) more likely to have LL loss. Conclusion Loss of initial regional and global sagittal correction is common in ASD surgery and also occurs inside the instrumented segments between 6 weeks and 2 years postop. Older age and pre-op sagittal deformity are risk factors for overall loss of correction and for loss of correction within the instrumented segments. In our study, interbody fusion was only protective for LL loss &gt; 10 deg.

Classification of Degenerative Segment Disease in Adults with Deformity of the Lumbar or Thoracolumbar Spine

Introduction Lumbar and thoracolumbar deformity in the adult is a condition with impairment of health status that can need surgical treatment. In contrast with adolescent deformity, where magnitude of the curve plays a significant role in surgical indication, the aspects relevant in adult deformity are pain and dysfunction that correlate with segment degeneration and imbalance. Previous classifications of adult deformity have been of little use for surgical planning. Materials and Methods Chart review and classification of radiographic and clinical findings. A classification of degenerative disc disease based on distribution of diseased segments and balance status of the spine is presented. Results Four main categories are presented: Type I (limited nonapical segment disease), Type II (limited apical segment disease), Type III (extended segment disease: apical and nonapical), and Type IV (imbalanced spine: IVa, sagittally imbalanced; IVb, sagittally and coronally imbalanced). Conclusion Types I and II can be treated by fusion of a selective area of the curve. Type III needs fusion of all the extension of the coronal curve. Type IV usually needs aggressive corrective procedures, frequently including posterior tricolumnar osteotomies. This classification permits interpreting the extension and magnitude of the disease and can help establish a surgical plan regarding selective fusion and methods of sagittal correction. Future research is needed to validate the classification.

The Effect of Metal Density on Coronal and Sagittal Curve Correction in Thoracic Adolescent Idiopathic Scoliosis

Introduction The literature is contradictory regarding the effect of metal density on correction of thoracic AIS. Given the rising cost of surgery for AIS, instrumentation should be used rationally. We aim to assess the impact of metal density on coronal and sagittal correction of AIS and assess if larger, less flexible curves necessitate high metal density. Material and Methods It is a retrospective multicenter case series. Inclusion criteria: Lenke 1–2 AIS, curve flexibility assessed by fulcrum-bending technique, single stage posterior only surgery, constructs using &gt; 80% screws, variable metal density, and &gt; 2-year follow-up. Outcome measures: Coronal main thoracic (MT) and lumbar curve correction, fulcrum-bending correction index (FBCI), thoracic kyphosis, lumbosacral lordosis, metal density (number of instrumented pedicles vs. total available), and fusion length. Surgical technique: Standard technique used in all centers employed extra hard titanium–aluminum–niobium alloy 6 mm diameter rods (DePuy Synthes, Raynham, Pennsylvania, United States) with reduction of the curvature via cantilever-segmental translation maneuvers. Implant location and density was according to curve stiffness and intraoperative bone density. The majority of the implants were on the thoracic curve convexity. Analysis: Bivariate analysis of outcome measures. Given the numerous correlations performed, a Bonferroni corrected p value was used, p &lt; 0.005. Two groups of pairs matched by curve type and exact fusion levels but differing MT curve magnitude were compared using student t-test. Outcomes for the quartiles of preoperative MT flexibility were compared using an ANOVA. Results A total of 106 patients, 94 were female patients. A total of 78 patients had Lenke 1 and 28 had Lenke 2. Mean age was 14 years. Bivariate analysis: No significant correlations were present between metal density and coronal curve correction rates of the MT (r = 0.13, p = 0.19) or lumbar curves (r = ␂ 0.15, p = 0.12) or FBCI; MT (r = ␂ 0.1, p = 0.31), lumbar (r = 0.00, p = 0.97). Metal density had no effect on change in thoracic kyphosis (r = 0.22, p = 0.04) or lumbosacral lordosis (r = 0.27 p = 0.01). Longer fusion length was associated with greater loss of thoracic kyphosis (r = ␂ 0.31, p = 0.003) and less postoperative thoracic kyphosis (r = ␂ 0.31, p = 0.003) but did not affect lumbosacral lordosis. Curve magnitude: Two groups of 21 matched cases from preoperative MT curve magnitude (&lt; 70 vs. ≥ 70 degrees) treated with comparable metal density (54 vs. 57%, p = 0.4) had equivalent MT and lumbar curve correction rates and FBCI. Sagittal profile changes did not differ significantly. Flexibility: No significant differences in MT, lumbar, and sagittal curve changes were present among the four MT flexibility quartiles (&lt; 32, 33–43, 43–51, 52–87%) despite all groups receiving comparable metal density (58, 58, 60, 62%, p = 0.2). Conclusion Metal density does not affect coronal and sagittal plane correction in surgery for thoracic AIS. Longer fusion length adversely affects sagittal profile. Larger and less flexible curves do not necessarily require high metal density.

Lateral access surgery for adult deformity: video lecture.

• To illustrate the use of classification systems to define the indications for selective fusion and fusion area in adult scoliosis. • To describe the indications for aggressive sagittal correction methods in adult scoliosis. • To describe lateral surgery-based methods for aggressive correction of sagittal imbalance. • To illustrate the use of classification methods for selection of the fusion area in sagittal imbalance.

Correlation between spinopelvic parameters and clinical outcomes after 2-stage sagittal malalignment correction in a prospective adult spinal deformity cohort

Correlation between spinopelvic parameters and clinical outcomes after 2-stage sagittal malalignment correction in a prospective adult spinal deformity cohort

Two and three-stage revision sagittal plane correction obviating the need for three-column spinal osteotomy for severe progressive sagittal malalignment

Two and three-stage revision sagittal plane correction obviating the need for three-column spinal osteotomy for severe progressive sagittal malalignment

Lung volume change after pedicle subtraction osteotomy in patients with ankylosing spondylitis with thoracolumbar kyphosis.

A retrospective clinical study. To investigate the lung volume (LV) change in patients with ankylosing spondylitis (AS) with thoracolumbar kyphosis after the pedicle subtraction osteotomy procedure. Thoracolumbar kyphosis with respiratory impairment is the consequence of most untreated AS patients. Restrictive pulmonary function is prevalent in these patients. The ideal evidence for restrictive pulmonary function impairment is to investigate the LV. A computed tomography (CT)-based method can help to obtain accurate LV change during the osteotomy. Twenty-eight patients with AS with thoracolumbar kyphosis were included. All of these patients underwent pedicle subtraction osteotomy to correct their sagittal deformity. Pre- and postoperative full-length radiographs and CT scans were reviewed. The sagittal correction of the spine was measured. CT scans were used to estimate the pre- and postoperative LV with software. The relationship between the sagittal correction and the LV change was investigated. All the patients were followed up for 2 years at least. The pedicle subtraction osteotomy procedure was performed safely on each patient without serious complications. The average preoperative T1-S1 Cobb was 67.7° (42°∼88°) and the postoperative was 7.6° (-11°∼21°). T1-S1 Cobb change was 60.0° in average (P < 0.05). The LV increased by 396 mL in average. Significant correlation was found between the percentage of LV change and T1-S1 Cobb change (r = 0.7219, P < 0.05). The location we selected for pedicle subtraction osteotomy varied from T12 to L3. No relationship was found between the osteotomy location and the LV change. The pedicle subtraction osteotomy effectively corrected the sagittal deformity of patients with AS. LV increased significantly after the osteotomy. 4.