Correction Of Thoracic Kyphosis Research Articles

Influence of pelvic tilt correction on PJK occurrence after adult spinal deformity surgery.

Many risk factors for proximal junctional kyphosis (PJK) have been reported in the literature, especially sagittal alignment modifications, but studies on pelvic tilt (PT) variations and its influence on PJK are missing. Aim of this study was to analyze the influence of pelvic tilt correction, after long fusion surgery for ASD patients, on PJK occurrence. A monocentric retrospective study was conducted on prospectively collected data, including 76 patients, operated with fusion extending from the thoraco-lumbar junction to the ilium. Radiologic parameters were measured on fullspine standing radiographs preoperatively, postoperatively (<6 months) and at latest follow-up (before revision surgery or >2 years). All parameters were analyzed comparing patients with PJK (group "PJK") and without PJK (group "no PJK"). A further analysis compared patients with low (PT/PI<25th percentile, LowPT group) and high (PT/PI>75th percentile, HighPT group) preoperative pelvic tilt. « PJK » patients had a greater lumbar lordosis and thoracic kyphosis correction (p=0,03 et <0,001 respectively) compared to the "no PJK" patients. Pelvic tilt was significantly lower postoperatively in the "PJK" group (p=0,03). Patients from the HighPT PJK group were significantly more corrected than patients from the HighPT noPJK group (p=0,003). Through the analysis of 76 patients, we showed that pelvic tilt did not seem to play a role in the setting of PJK after ASD surgery. Decreasing PT after surgery could be an element to watch out for in patients with PJK risk factors.

How to make a more optimal surgical plan for Lenke 5 adolescent idiopathic scoliosis patients: a comparative study based on the changes of the sagittal alignment and selection of the lowest instrumented vertebra

BackgroundThe treatment of patients with Lenke 5 adolescent idiopathic scoliosis (AIS) is closely related to the pelvic because the spine–pelvis is an interacting whole. Besides, the choice of fusion segment is a significant issue; with the optimal choice, there will be fewer complications and restoring the pelvic morphology to some extent. This study aims to analyze the impact of changes in sagittal parameters and selection of the lowest instrumented vertebra (LIV) on spine and pelvic morphology for better surgical strategy.MethodNinety-four patients with Lenke 5 AIS who underwent selective posterior thoracolumbar/lumbar (TL/L) curve fusion were included in the study and grouped according to pelvic morphology and position of LIV. Spinopelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. The patient’s preoperative and last follow-up quality of life was assessed with the MOS item short-form health survey (SF-36) and scoliosis research society 22-item (SRS-22).ResultPatients being posterior pelvic tilt had the oldest mean age (P = 0.010), the smallest lumbar lordosis (LL) (P = 0.036), the smallest thoracic kyphosis (TK) (P = 0.399) as well as the smallest proximal junctional angle (PJA) while those being anterior pelvic tilt had the largest PJA. The follow-up TK significantly increased in both groups of anterior and normal pelvic tilt (P < 0.039, P < 0.006) while no significant changes were observed in the posterior pelvic tilt group. When LIV is above L4, the follow-up PJA was larger than other groups (P = 0.049, P = 0.006). When LIV is below L4, the follow-up TK and PT were larger and LL was smaller than other groups(P < 0.05). The SF-36 and SRS-22 scores were better in the LIV = L4 group than in other groups at the last follow-up (P < 0.05).ConclusionThe correction of TK and LL after surgery can improve pelvic morphology. Besides, LIV is best set at L4, which will facilitate the recovery of TK, the improvement of symptoms, and the prevention of complications and pelvic deformities.Level of evidence Level III.

No short-term clinical improvement and mean 6° of thoracic kyphosis correction using limited-level Ponte osteotomy near T7 for Lenke type 1 and 2 adolescent idiopathic scoliosis: a preliminary study.

This study was a retrospective single surgeon case series approved by institutional review board and showed the efficacy of limited Ponte osteotomy at T6/7, 7/8 and 8/9 (limited-PO) in the sagittal plane for patients with Lenke type 1 and 2 adolescent idiopathic scoliosis (AIS). A total of 37 consecutive patients [7 males and 30 females; average age 16.0 ± 2.5 (range: 12-21)] over a 4-year period with posterior corrective fusion surgery were included. Initially, 18 patients were operated on without limited-PO [P(-)-group]. Midway in the series, the senior author switched to the limited-PO [P(+)-group]. The limited-PO has been performed to form the apex of thoracic kyphosis at the T7 level, together with the restoration of thoracic kyphosis. The mean amount of the correction angle of thoracic kyphosis was more in the P(+)-than in P(-)-group (13.8 ± 9.6° vs. 7.8 ± 8.0°, P = 0.046) at 1-year after surgery. Cervical lordosis was spontaneously corrected more in P(+)-than in P(-)-group. The apex of thoracic kyphosis was controlled around the T7 level postoperatively in most cases (18/19 cases). There was no significant difference between the two groups in terms of blood loss and operative time per level, or Scoliosis Research Society-22 domain scores. Limited-PO contributed to the restoration of the whole spinal sagittal alignment for Lenke type 1 and 2 AIS; however, in this preliminary study, the clinical improvement was unclear at least in the short term, because the kyphosis angle obtained by limited-PO was only approximately 6°.

Radiographic Outcomes of the Short and Intensive Rehabilitation (SHAiR) Program in Patients with Dropped Head Syndrome.

The radiographic outcomes of nonoperative treatment of dropped head syndrome are still unknown. The purpose of the present study was to assess the change in sagittal spinopelvic radiographic parameters after the short and intensive rehabilitation (SHAiR) program in patients with dropped head syndrome. This study included 48 consecutive patients with dropped head syndrome who presented with an inability to maintain horizontal gaze and who underwent the SHAiR program during the period of 2018 to 2019. Patients were divided into 2 groups according to their ability to maintain horizontal gaze at the time of final follow-up: those who had regained horizontal gaze (the "effective" group) and those who had not regained horizontal gaze (the "noneffective" group). Sagittal radiographic parameters including the sagittal vertical axis (SVA), the C2-7 angle, the C2-7 SVA, T1 slope, thoracic kyphosis of T1-5 and T5-12, lumbar lordosis, pelvic tilt, pelvic incidence, sacral slope, and curve flexibility, and demographic data and clinical outcomes were compared between the 2 groups using an unpaired t test, chi-square test, and Fisher exact test, as appropriate. Thirty-five patients in the effective group and 13 patients in the noneffective group were analyzed. The rate of response in regaining horizontal gaze with the SHAiR program was 73%. The C2-7 angle, the C2-7 SVA, T1 slope, and thoracic kyphosis (T1-5) demonstrated significant correction in the effective group (p < 0.05). There were no significant changes in other parameters below the mid-thoracic spine-i.e., the thoracolumbar and lumbar spine and pelvis-following the SHAiR program. Scores of the Neck Disability Index and visual analog scale for pain improved significantly in both groups. The SHAiR program improved horizontal gaze among a large percentage of our patients and reduced cervical pain among patients overall. The correction of thoracic kyphosis (T1-5) might be an important treatment target to restore the appropriate T1 tilt in patients with dropped head syndrome. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

All Pedicle Screw versus Hybrid Hook-Screw Instrumentation in the Treatment of Thoracic Adolescent Idiopathic Scoliosis (AIS): A Prospective Comparative Cohort Study.

Background: Posterior spinal correction and fusion remains the most common surgical treatment in AIS. Surgeons currently favour all pedicle screw (AS) correction techniques with alternative implants being less utilised. The purpose of this study was to assess whether a hybrid hook–screw (HS) construct could achieve similar outcomes. Methods: A single centre, prospective cohort study was conducted. Patients with moderate and severe thoracic AIS (Lenke 1) were included. Clinical and radiological results of a standardised hybrid HS technique were compared with those obtained with an AS construct. All patients had a minimum 2-year follow-up. Results: 160 patients were included in this series (80 patients/group). The HS group had significantly reduced surgical time, blood loss and implant density. Both techniques achieved ≥75% scoliosis correction. The HS group was superior in restoring thoracic kyphosis and global sagittal balance with an average 31% increase in kyphosis compared to 10% with the AS group (p < 0.001). There was significant improvement in SRS-22 scores at 2 years postoperative (p < 0.001) in both groups. There were no neurological or visceral complications related to instrumentation, no detected non-union and no reoperations. The HS implant cost was significantly lower than that of AS, with a mean instrumentation saving of almost £2000/patient. Conclusion: A standardised hybrid HS technique achieved excellent correction of thoracic scoliosis, high patient satisfaction and low complication rates in patients with thoracic AIS. These results were comparable to the AS group. The HS technique achieved better correction of thoracic kyphosis and sagittal balance than the AS technique, together with reduced surgical time, blood loss and implant cost.

Rod Link Reducer system in adolescent idiopathic scoliosis: a retrospective observational trial.

The Rod Link Reducer (RLR) (Globus Medical, PA, USA) allows direct three-dimensional correction of the spine deformity follows the direct vertebral rotation (DVR) theories. The purpose of this retrospective study is to compare RLR with traditional correction technique (TCT) in two cohorts of patients with adolescent idiopathic scoliosis (AIS). Fifty-four patients (M:F = 1:8) between 2018 and 2020 were included. The first group (n = 22) was treated by RLR while the second one (n = 32) by TCT. All spines were classified as per the Lenke system. Length of hospitalization, days in intensive care unit (ICU), operative time, and blood loss were recorded. SRS-30 and SF-36 questionnaires were administered pre-operative and post-operative. We collected radiological data: pre-operative and post-operative Cobb angles, coronal and sagittal balance, trunk and thoracic height. RLR and TCT groups are homogeneous in age (p = 0.317), sex ratio (p = 0.347), and Risser stage (p = 0.222). Between both groups there was no significant statistical difference in haemoglobin value, hospitalization length, days in ICU, operative times, SF-36, SRS-30, NRS, and perceived satisfaction. RLR group shows a better improvement of correction of main thoracic (MT) curve (RLR 54.2% ± 15.9%/TCT 38.1% ± 20.4%, p = 0.031). Nevertheless, RLR group shows a worse thoracic kyphosis correction (RLR 16.82° ± 9.13°/27.12° ± 12.13°, p = 0.015). RLR system allows a more effective MT curve correction than TCT systems, but it seems to give a hypokyphosis effect.

Posterolateral approach to the thoracic spine for spinal tuberculosis: A Technical Note and an Analysis of Results

Surgical pathologies in the thoracic spine are principally located anteriorly within the vertebral body resulting in vertebral body destruction, kyphotic deformity, and anterior or anterolateral compression of the spinal cord. Adequate decompression of the neural elements and vertebral body reconstruction requires access to the anterior spinal column. The posterolateral approach through a posterior midline incision allows circumferential spinal cord decompression, anterior column reconstruction, correction of thoracic kyphosis, and posterior spinal stabilization to be safely performed through a single incision, at a single sitting with excellent outcomes.

Long-term outcome after surgical treatment of Scheuermann's Kyphosis (SK).

A retrospective observational cohort study with a minimum follow-up of 10years of patients who underwent surgery for Scheurmann Kyphosis (SK). Evaluate the long-term clinical and radiological outcome of patients with SK who either underwent combined anterior-posterior surgery or posterior instrumented fusion alone. There is paucity of literature for long-term outcome studies on SK. The current trend is towards only posterior (PSF) surgical correction for SK. The combined strategy of anterior release, fusion and posterior spinal fusion (AF/PSF) for kyphosis correction has become historic relic. Long-term outcome studies comparing the two procedures are lacking in literature. 51 patients (30M: 21F) who underwent surgery for SK at a single centre were reviewed. Nineteen had posterior instrumentation alone (PSF) (Group 1) and 32 underwent combined anterior release, fusion with posterior instrumentation (AF/PSF) (Group 2). The clinical data included age at surgery, gender, flexibility of spine, instrumented spinal levels, use of cages and morcellised rib grafts (in cases where anterior release was done), posterior osteotomies and instrumentation, complications and indications for revision surgery. Preoperative flexibility was determined by hyperextension radiographs. The radiological indices were evaluated in the pre-operative, 2-year post-operative and final follow-up [Thoracic Kyphosis (TK), Lumbar lordosis (LL), Voustinas index (VI), Sacral inclination (SI) and Sagittal vertical axis (SVA)]. The loss of correction and incidence of JK (Junctional Kyphosis) and its relation to fusion levels were assessed. Complications and difference in outcome between the two groups were analyzed. The mean age at surgery for 51 patients was 20.6years who were followed up for a minimum of 10years (mean: 14years; range 10-16years). The mean age was 18.5 ± 2.2years and 21.9 ± 4.8years in groups 1 and 2, respectively. The mean pre- and 2-year post-operative ODIs were 32.6 ± 12.8 and 8.4 ± 5.4, respectively, in group 1 (p < 0.0001) and 30.7 ± 11.7 and 6.4 ± 5.7, respectively, in group 2 (p < 0.0001). The final SRS-22 scores in group 1 and 2 were 4.1 ± 0.4 and 4.0 ± 0.35, respectively (p = 0.88). The preoperative flexibility index was 49.2 ± 4.2 and 43 ± 5.6 in groups 1 and 2, respectively (p < 0.0001). The mean TKs were 81.4° ± 3.8° and 86.1° ± 6.0° for groups 1 and 2, respectively, which corrected to 45.1° ± 2.6° and 47.3° ± 4.8°, respectively, at final follow-up (p < 0.0001). The mean pre-operative LL angle was 60.0° ± 5.0° and 62.4° ± 7.6° in groups 1 and 2, respectively, which at final follow-up was 45.1° ± 4.4° and 48.1° ± 4.8°, respectively (p < 0.0001). The mean pre-operative and final follow-up Voustinas index (VI) in group 1 were 22.9 ± 2.9 and 11.2 ± 1.2, respectively, and in group 2 was 25.9 ± 3.5 and 14.0 ± 2.3, respectively. The mean pre-operative and final follow-up SI angle were 43.6° ± 3.3° and 31.2° ± 2.5° in group 1, respectively, and 44.3° ± 3.5° and 32.1° ± 3.5° in group 2, respectively (p < 0.0001). The pre-operative and final follow-up SVA in group 1 were -3.3 ± 1.0 cms and -1.3 ± 0.5 cms, respectively, and in group 2 was -4.0 ± 1.3cms and -1.9 ± 1.1cms, respectively (p < 0.0001). Though the magnitude of curve correction in the groups 1 and 2 was significant 36° vs 39° (p = 0.05), there was no significant difference in correction between the two groups. Proximal JK was seen in seven and distal JK in five patients were observed in the whole cohort. The long-term clinical outcomes for both PSF and AF/PSF are comparable with reproducible results. No difference was noted in loss of correction and outcome scores between the two groups. The correction of thoracic kyphosis (TK) had a good correlation with ODI. AF/PSF had much higher complications than PSF group. The objective of correcting the sagittal profile and balancing the whole spinal segment on the pelvis can be achieved through single posterior approach with fewer complications.

Recurrence of proximal junctional kyphosis after revision surgery for symptomatic proximal junctional kyphosis in patients with adult spinal deformity: incidence, risk factors, and outcomes.

Although proximal junctional kyphosis (PJK) is common after long spinal fusion, the outcomes of revision surgery for symptomatic PJK are unclear. Our aim was to assess the outcomes of revision surgery for symptomatic PJK in patients with adult spinal deformity and elucidate the incidence and risk factors for recurrent PJK (rePJK). We evaluated standing radiographs and health-related quality of life (HRQOL) in patients who underwent revision surgery for symptomatic PJK with at least 2-year follow-up. Patients were assigned to the non-rePJK or rePJK group according to PJK recurrence. Thirty-nine consecutive patients (mean age, 63 ± 11years; 24 women) met the inclusion criteria. RePJK occurred in 12 patients (31%). There were significant differences in the following parameters between groups (non-rePJK vs. rePJK): initial proximal junctional sagittal Cobb angle (PJA) (26.6° vs. 35.6°), thoracic kyphosis (TK) (38.6° vs. 52.8°), and sagittal vertical axis (SVA) (9.3 vs. 15.9cm), and pre- to postoperative SVA decrease (6.1 vs. 12.2cm). Significant risk factors for rePJK were initial PJA > 40°, preoperative TK > 60°, preoperative SVA > 10.0cm, correction of TK > 15°, and correction of SVA > 5.0cm. HRQOL scores improved significantly; however, postoperative SRS-22r activity scores were significantly worse in the rePJK group vs the non-rePJK group. The incidence of rePJK was 31%. Risk factors for rePJK were large initial PJA, high preoperative TK and SVA, and greater correction of TK and SVA. HRQOL did not differ significantly between patients with vs without rePJK, except immediate postoperative SRS-22r activity scores. III.

A Retrospective Study of Factors Associated with Restoration of Thoracic Kyphosis in 43 Patients with Adolescent Idiopathic Scoliosis with Lenke Type 1 Curvature.

BackgroundThis retrospective study aimed to identify the factors associated with successful surgical correction of thoracic kyphosis (TK) in 43 patients with adolescent idiopathic scoliosis (AIS) with Lenke type 1 curvature, in which the major curve with the largest Cobb angle was mainly in the thoracic region.Material/MethodsWe collected data from patients with Lenke 1 AIS. The following parameters were measured: Cobb angle, side-bending Cobb angle, cervical lordosis (CL), TK, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), the sagittal vertical axis (SVA), the center of a C7 plumb line to the center sacral vertical line (C7-CSVL), correction rate, Ponte osteotomy, flexibility, and screw density. Univariate analysis and multivariate logistic regression analyses were performed.ResultsAmong the 43 cases analyzed, the mean postoperative Cobb angle at the last follow-up, C7-CSVL, SVA, CL, TK, LL, PI, SS, and PT were respectively 21.33±9.47°, 10.41±8.45 mm, 19.68±14.33 mm, 16.19±7.45°, 23.12±7.45°, 50.33±11.37°, 49.70±9.83°, 39.42±8.11°, and 10.16±6.63°. Univariate analysis suggested that preoperative TK, preoperative LL, and Ponte osteotomy were statistically significant (P<0.05), and multivariate analysis suggested that preoperative LL and Ponte osteotomy were statistically significant (P<0.05).ConclusionsThe results of this study demonstrated that preoperative TK, preoperative LL, and Ponte osteotomy were related factors for maintaining normal TK. Multivariate analysis suggested that preoperative LL and the use of Ponte osteotomy with full-thickness segmental resection of the spinal posterior column resulted in the successful surgical correction of TK in patients with AIS with Lenke type 1 curvature.

Posterior-only versus combined anterior-posterior fusion in Scheuermann disease: a systematic review and meta-analysis.

Combined anterior-posterior (AP) surgery is considered the gold standard for surgical treatment of Scheuermann kyphosis. There are trends toward posterior-only (PO) surgery for correcting this deformity because of the availability of multisegmental compression instruments and posterior shortening osteotomy. To date, surgical strategies for Scheuermann kyphosis remain controversial. The purpose of this study was to compare various surgical approaches for the treatment of Scheuermann kyphosis, including radiological correction and intraoperative outcomes, using a systematic review and meta-analysis. A comprehensive database search of PubMed, EMBASE, Web of Science, and Cochrane Library was performed to identify studies concerning Scheuermann kyphosis. The inclusion criteria were direct comparisons between AP and PO surgeries for Scheuermann kyphosis and assessment of the angle of thoracic kyphosis preoperatively and postoperatively. The authors used the principles of a cumulative meta-analysis by updating the pooled estimate of the treatment effect. Data from 13 studies involving 1147 participants (542 patients in the AP group and 605 patients in the PO group) were included. The average age was 18.2 years for the AP and 17.9 years for the PO group. The overall mean difference of changes in thoracic kyphosis angles between the AP and PO surgeries was 0.23° (95% CI -2.24° to 2.71°). In studies in which posterior shortening osteotomies were not performed, PO surgery resulted in a significantly low degree of correction of thoracic kyphosis, with a mean difference of 5.59° (95% CI 0.34°-10.83°). Studies in which osteotomies were performed revealed that the angle of correction for PO surgery was comparable to that of AP surgery. Regardless of fixation methods, PO surgical approaches achieved comparable angles. PO surgery using posterior osteotomies can achieve correction of Scheuermann kyphosis as successfully as AP surgery does. Reflecting the advancement of surgical technology, large prospective studies are necessary to identify the proper treatments for Scheuermann kyphosis.

232. Optimal lumbar lordosis correction for adult spinal deformity with severe sagittal imbalance in patients over age 65: role of pelvic tilt and pelvic tilt ratio

BACKGROUND CONTEXT The prevalence of adult spinal deformity (ASD) is increasing as the average age of the population increases. Optimal surgical correction for patients with ASD is necessary. The Scoliosis Research Society-Schwab classification is used for optimal surgical correction in many spinal reconstruction surgeries, and the targets to obtain satisfactory alignment and favorable outcomes are ≤10° for pelvic incidence (PI) minus lumbar lordosis (LL), 20°, while pathologic based on Schwab criteria, may be a natural phenomenon in patients with a large PI. Therefore, the concept of global tilt has been introduced recently, and to overcome the limitations of PT in our study, a PT ratio value (PTr) of PT/PI x 100% was calculated along with measurement of PT. PURPOSE The purpose of this study was to evaluate optimal and ideal target values including PTr of the spine balance correction in elderly patients with ASD who were over the age of 65 years. STUDY DESIGN/SETTING Retrospective, consecutive case review. PATIENT SAMPLE A total of 121 patients (average age 70.5 years and a minimum 2-year follow up) with lumbar degenerative kyphosis (LDK) who underwent long-segment fusion from T10 to sacrum. OUTCOME MEASURES Description and analysis of x-ray changes. METHODS Based on the correction angle of their LL and incorporating PI, the patients were divided into 5 groups using the Schwab classification. Clinical and radiologic parameters were analyzed: Group 1 was 10 RESULTS The groups that showed 80% or more optimal sagittal alignment at their postoperative (Post) and the last follow-up (Last), were group 3, 4, and 5. Post and Last thoracic kyphosis (TK) were increased naturally. Post PT was decreased, but group 1 and 2 did not meet Schwab's target value, and the Post and Last PTr showed a tendency to decrease from group 1 to group 5 as LL increased. Based on correlation test with Post SVA, TK correction and SVA correction, Post lumbosacral angle, Post LL, PI–LL, Post PTr and Post PT were associated. Logistic regression analysis with these correlation factors led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of PI–LL and Post PTr were valid (p CONCLUSIONS Our study showed that undercorrection showed unfavorable results for the correction of LDK patients over age 65. Therefore, the restoration of global sagittal balance is more important, and through our study, the risk factors of Post sagittal imbalance were the value of PI–LL and that of PTr, and target value of PI-LL was FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Restoration of Thoracic Kyphosis in Adolescent Idiopathic Scoliosis Over a Twenty-year Period: Are We Getting Better?

A multicenter, prospectively collected database of 20 years of operatively treated adolescent idiopathic scoliosis (AIS) was utilized to retrospectively examine pre- and postoperative thoracic kyphosis at 2-year follow-up. To determine if the adoption of advanced three-dimensional correction techniques has led to improved thoracic kyphosis correction in AIS. Over the past 20 years, there has been an evolution of operative treatment for AIS, with more emphasis on sagittal and axial planes. Thoracic hypokyphosis was well treated with an anterior approach, but this was not addressed sufficiently in early posterior approaches. We hypothesized that patients with preoperative thoracic hypokyphosis prior to 2000 would have superior thoracic kyphosis restoration, but the learning curve with pedicle screws would reflect initially inferior restoration and eventual improvement. From 1995 to 2015, 1063 patients with preoperative thoracic hypokyphosis (<10°) were identified. A validated formula for assessing three-dimensional sagittal alignment using two-dimensional kyphosis and thoracic Cobb angle was applied. Patients were divided into 1995-2000 (Period 1, primarily anterior), 2001-2009 (Period 2, early thoracic pedicle screws), and 2010-2015 (Period 3, modern posterior) cohorts. Two-way repeated measures analysis of variance and post-hoc Bonferroni corrections were utilized with P < 0.05 considered significant. Significant differences were demonstrated. Period 1 had excellent restoration of thoracic kyphosis, which worsened in Period 2 and improved to near Period 1 levels during Period 3. Period 3 had superior thoracic kyphosis restoration compared with Period 2. Although the shift from anterior to posterior approaches in AIS was initially associated with worse thoracic kyphosis restoration, this improved with time. The proportion of patients restored to >20° kyphosis with a contemporary posterior approach has steadily improved to that of the era when anterior approaches were more common. 3.

Patient-specific rods for thoracic kyphosis correction in adolescent idiopathic scoliosis surgery: Preliminary results

IntroductionRestoring a degree of kyphosis consistent with good sagittal alignment of the spine is a key concern when performing surgery to correct adolescent idiopathic scoliosis (AIS). The objective of this study was to assess the preliminary outcomes of posterior fusion for AIS using patient-specific rods that were pre-contoured based on pelvic incidence. The primary evaluation criterion was thoracic kyphosis at last follow-up. HypothesisThe use of pre-bent patient-specific rods has a favourable effect on thoracic kyphosis at last follow-up. Material and methodsA total of 37 patients with AIS, including 17 with hypokyphosis, managed with patient-specific rods were included in a prospective study. The rod contouring angles were based on predefined pelvic incidence criteria (25° to 40° for the rod on the convex side and the same value plus 10° for the rod on the concave side). Thoracic kyphosis was assessed before surgery and at last follow-up, after 12–36 months (mean, 19 months). Student's t test was applied to compare means. Multivariate linear regression analysis was performed. ResultsAt last follow-up, the mean increase in kyphosis was 14° and was comparable to the planned increase (mean difference=0, p=0.85). Factors associated with kyphosis at last follow-up were the concave rod contouring angle and the pre-operative kyphotic angle of the thoracic segment to be instrumented (p<0.05). Mean differences between kyphosis of the instrumented thoracic segment at last follow-up and target kyphosis were −5° in the subgroup with hypokyphosis (<20°) before surgery and +4° in the subgroup with normal kyphosis before surgery. ConclusionWith patient-specific rods, kyphosis at last follow-up was close to the target value. Predictors of kyphosis at last follow-up were the concave rod contouring angle and pre-operative kyphotic angle of the thoracic segment to be instrumented. Over-contouring of the concave rod seems necessary in patients with preoperative hypokyphosis but not in patients with normal kyphosis. Level of evidenceIII, prospective non-comparative study.

The correlations between the anchor density and the curve correction of adolescent idiopathic scoliosis surgery

BackgroundThe optimal anchor density in adolescent idiopathic scoliosis (AIS) surgery to achieve good curve correction remains unclear. The purpose of the study is to analyze the correlations between three-dimensional curve correction and anchor density in the pedicle screw-based posterior fusion of AIS.MethodsOne hundred and twenty-seven AIS patients receiving primary posterior fusion with pedicle screw instrumentation were retrospectively reviewed. Anchor density (AD) was defined as the screws number per fused spinal segment. The correlations between three-dimensional curve correction radiographic parameters and anchor density were analyzed with subgroup analysis based on different curve types, curve magnitudes, and curve flexibilities. The differences of curve correction parameters between the low-density (AD ≤1.4), middle-density (1.4 < AD ≤1.7) and high-density (AD > 1.7) groups were also calculated. Independent t-test, analysis of variance (ANOVA), and Pearson’s correlation coefficient were used for statistical analysis.ResultsThere were no correlations between the anchor density and the coronal curve correction or apical vertebral rotation (AVR) correction. In the sagittal plane, mild positive correlations existed between anchor density and thoracic kyphosis correction in all patients (r = 0.27, p = 0.002). Subgroup analysis revealed similar mild positive correlations in Lenke 1 (r = 0.31, p = 0.02), Lenke 1–3 (r = 0.27, p = 0.01), small curves (40°-60°, r = 0.38, p < 0.001), and flexible curves (flexibility > 40%, r = 0.34, p = 0.01).There were no differences between low-density (mean 1.31), middle-density (mean 1.55), and high-density (mean 1.83) in terms of coronal or axial curve correction parameters. Low-density group has longer fused level (mean difference 2.14, p = 0.001) and smaller thoracic kyphosis correction (mean difference 9.25°, p = 0.004) than high-density group.ConclusionIn our study, the anchor density was not related to coronal or axial curve corrections. Mild positive correlations with anchor density were found in thoracic kyphosis correction, especially in patients with smaller and flexible curves. Low anchor density with longer fusion level achieves similar curve corrections with middle or high anchor density in adolescent idiopathic scoliosis surgery.

25. Use of precontoured titanium alloy rods to induce thoracic kyphosis after sequential posterior release: a cadaveric spine study

BACKGROUND CONTEXT Implications for failure to restore normal thoracic kyphosis (TK) in treating adolescent idiopathic scoliosis are just beginning to be understood. Techniques for releasing the rigid spine have included ligamentous releases and discectomy procedures, as well as bony resection; however, the extent these releases improve the ability for a precontoured rod to induce thoracic kyphosis has been lacking. PURPOSE Evaluate the ability of precontoured rods to induce thoracic kyphosis in a cadaveric spine and determine the effectiveness of sequential posterior releasing procedures. STUDY DESIGN/SETTING In vitro biomechanical study. OUTCOME MEASURES Sagittal Cobb measurement of T4-12 construct as well as superior, mid and inferior regions. METHODS Dissected 6 fresh thoracolumbar (T3-L2) spine specimens and acquired lateral and anteroposterior radiographs to: confirm all levels were mobile; exclude pathological conditions; and assess sagittal Cobb angle (T4-T12). Pedicle screws were placed from T4-T12 bilaterally. Intact status was defined by over correcting the initial sagittal cobb measurement and reducing the precontoured, bilateral titanium alloy rods. Cobb measurements were repeated following rod reduction. Removed rods and repeated over correction process for the following release procedures implemented sequentially: (1) interspinous and supraspinous ligaments (ISL) transection; (2) ligamentum flavum transection; (3) Ponte osteotomy; (4) posterior longitudinal ligament transection (PLL); and (5) lateral discectomy. Used a novel rod-bender to create consistent, over corrected contoured rods at each step. Collected data on the radius of each rod's curvature before and after each reduction. Cobb measurements collected on the instrumented construct for each procedure. Comparisons determined the effective contribution of each sequential release on the inducement of TK. RESULTS Initial sagittal kyphosis from T4-12 was 38° and kyphosis increased to 52° with over correction with the precontoured rods applied. Each release resulted in 5-7° of additional kyphosis, and largest releases were ISL and PLL. The ISL transection was not significantly different than the intact condition with rod correction. All subsequent releases resulted in significant (p CONCLUSIONS Increased kyphosis was created in the thoracic spine using precontoured rods. Subsequent posterior releases provided a substantial, meaningful clinical change in the ability to induce additional kyphosis. Although each posterior release was effective for induction of TK (ISL and PLL having largest increase), ISL transection alone was not statistically different than the intact condition with rods applied. More than one release was necessary to induce a significant change in TK compared to the over correction accomplished on the intact thoracic spine. Rod flattening consistently occurred following attempted over correction with rod reduction, although the thoracic spine was sequentially destabilized with each release. Therefore, a presurgical plan for TK correction may be limited regardless of the number of releases performed. FDA DEVICE/DRUG STATUS pre-contoured titanium alloy rods (Approved for this indication).

Long-term clinical and radiographic outcomes and patient satisfaction after adult spinal deformity correction.

Adult spinal deformity surgery has increased with the aging population and modern surgical approaches, although it has high complication and reoperation rates. The permanence of radiographic correction, mechanical complications, predictive factors for poor patient-reported outcomes, and patient satisfaction were analyzed. A total of 79 adult patients were retrospectively analyzed at baseline and 1-9 years after adult spinal deformity correction between 2007 and 2016. Patient-reported outcomes (Oswestry Disability Index, visual analog scale, and Scoliosis Research Society-30 scores), changes in radiographic alignment, indications for reoperation, predictors of poor outcomes according to the Oswestry Disability Index and Scoliosis Research Society-30 scores, and patient satisfaction with management were studied. Oswestry Disability Index and visual analog scale scores (p = 0.001), radiographic correction of thoracic kyphosis, lumbar lordosis, and pelvic retroversion (p ⩽ 0.001) and sagittal vertical axis (p = 0.043) were significantly better at 4-5 years of follow-up than at baseline. The risk for the first reoperation owing to mechanical failure of instrumentation or bone was highest within the first year, at 13.9% (95% confidence interval = 8.0%-23.7%), and 29.8% (95% confidence interval = 19.4%-43.9%) at the 5-year follow-up. Oswestry Disability Index and Scoliosis Research Society-30 total scores had a good correlation (r = -0.78; 95% CI = -0.86 to -0.68; p < 0.001). Satisfaction with management was correlated with patient-reported outcomes. Male sex and depression (p = 0.021 and 0.018, respectively) predicted poor outcomes according to the Oswestry Disability Index and/or Scoliosis Research Society-30 score. The achieved significant radiographic correction was maintained 5 years postoperatively. Despite reoperations, patient satisfaction and clinical outcomes were good. Depression and male sex predicted poor clinical outcomes.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P91. Lenke 1 adolescent idiopathic scoliosis: effects of TK restoration on regional and global alignment

BACKGROUND CONTEXT While historically the main focus in AIS was the coronal Cobb, there has been a growing interest in also integrating consideration for sagittal plane alignment. The effect of surgical thoracic kyphosis (TK) correction on adjacent curvatures remains unclear. PURPOSE This study aims to elucidate the reciprocal changes associated with TK correction in Lenke one-two AIS patients. STUDY DESIGN/SETTING Multicenter retrospective study. PATIENT SAMPLE A total of 155 AIS patients with Lenke one-two curves operated on with either surgical bands or pedicle screws were included. OUTCOME MEASURES Classic spino-pelvic parameters at baseline and 2years (2Y). METHODS Reciprocal changes associated to TK correction were analyzed, alignment predictive formulas were defined using 75% of the cohort and 25% for validation. RESULTS A total of 155 patients were included (15yo, 86% female), the majority of patients (92.9%) had T4-T12 completely fused. From pre to post, there was a significant decrease (all p CONCLUSIONS It is already known that the correction of one sagittal curve leads to changes in surrounding curves and it is well observed in this study that the correction of TK leads to changes in CL and LL. These changes are directly correlated to the magnitude of TK change, and are thus predictable. It is interesting to note that an inadequate restoration of TK from hypokyphosis will result in a greater PI-LL mismatch.In the setting of surgical planning; these formulas would be invaluable for the surgeons and could lead to better postop courses.

Comparison of Complications and Surgical Outcomes of Adolescent Idiopathic Scoliosis Between Junior Attending Surgeons and Senior Attending Surgeons

To our knowledge, few studies have compared complications and surgical outcomes of adolescent idiopathic scoliosis (AIS) between junior attending surgeons and senior attending surgeons. To compare surgical strategies, complications, and outcomes of posterior corrective surgery for AIS between junior attending surgeons and senior attending surgeons. According to experience level of operation surgeons, the patients were assigned to 2 groups. Group A was the "junior surgeon" group. Group B was the "senior surgeon" group. The following parameters were compared between the 2 groups: age, sex, diagnosis, hospital of record, surgeon experience level, type of instrumentation, type of screws, estimated blood loss, duration of surgery, length of fusion, correction techniques, main curve correction, and thoracic kyphosis correction. A total of 132 patients with AIS were included in group A, whereas 207 were in group B. The translational technique was used more often in group A (P < 0.05). whereas the derotation technique was used more often in group B (P < 0.05). Senior surgeons used more monoaxial screws than junior surgeons (P < 0.05). The junior group had significantly greater estimated blood loss than the senior group (P < 0.05). The senior group had significant better correction rates of severe main curve (>70°) and thoracic kyphosis than the junior group (P < 0.05). Senior attending surgeons outperformed junior surgeons in blood loss control, thoracic kyphosis correction, and correction of severe curves.

Reciprocal Changes in Sagittal Alignment in Adolescent Idiopathic Scoliosis Patients Following Strategic Pedicle Screw Fixation.

Study DesignRetrospective observational study.PurposeTo analyze the effect of low-density (LD) strategic pedicle screw fixation on the correction of coronal and sagittal parameters in adolescent idiopathic scoliosis (AIS) patients.Overview of LiteratureLD screw fixation achieves favorable coronal correction, but its effect on sagittal parameters is not well established. AIS is often associated with decreased thoracic kyphosis (TK), and the use of multi-level pedicle screws may result in further flattening of the sagittal profile.MethodsA retrospective analysis was performed on 92 patients with AIS to compare coronal and sagittal parameters preoperatively and at 2-year follow-up. All patients underwent posterior correction via LD strategic pedicle screw fixation. Radiographs were analyzed for primary Cobb angle (PCA), coronal imbalance, cervical sagittal angle (CSA), TK, lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope (SS), C7 plumb line, spino-sacral angle, curve flexibility, and screw density.ResultsPCA changed significantly from 57.6°±13.9° to 19°±8.4° (p <0.0001) with 67% correction, where the mean curve flexibility was 41% and screw density was 68%. Regional sagittal parameters did not change significantly, including CSA (from 10.76° to 10.56°, p =0.893), TK (from 24.4° to 22.8°, p =0.145), and LL (from 50.3° to 51.1°, p =0.415). However, subgroup analysis of the hypokyphosis group (<10°) and the hyperkyphosis group (>40°) showed significant correction of TK (p <0.0001 in both). Sacro-pelvic parameters showed a significant decrease of PT and increase of SS, suggesting a reduction in pelvic retroversion SS (from 37° to 40°, p =0.0001) and PT (from 15° to 14°, p =0.025).ConclusionsLD strategic pedicle screw fixation provides favorable coronal correction and improves overall sagittal sacro-pelvic parameters. This technique does not cause significant flattening of TK and results in a favorable restoration of TK in patients with hypokyphosis or hyperkyphosis.