Radiographic outcomes and complications after L4 or L5 pedicle subtraction osteotomy for fixed sagittal malalignment in 102 adult spinal deformity patients with a minimum 2-year follow-up.

PURPOSE: The objective of this retrospective study was to provide the radiographic outcomes and complications for pedicle subtraction osteotomy (PSO) performed at the low lumbar spine, i.e., L4 or L5 for ASD patients with fixed sagittal malalignment. METHODS: ASD patients who underwent L4 or L5 PSO with a minimum 2-year follow-up were included. Preoperative and postoperative radiographs, and complications were collected. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), thoracic kyphosis (TK), sagittal vertical axis (SVA), spinal lordosis (SL) ratio and global tilt (GT) on standing long-cassette radiographs. RESULTS: A total of 102 patients from 2 spinal centers were analyzed. 66 patients underwent PSO at L4 and 36 patients at L5. From preoperatively to the final follow-up, significant improvements occurred in LL (from - 31° to - 52°), SVA (from 13 to 5 cm), and GT (from 44° to 27°) (all, p < 0.05). 12 patients had transient neurological deficits, and 8 patients had persistent neurological deficit. 23 patients underwent revision for PJK (2), pseudarthrosis (10), neurological deficit (2), epidural hematoma (1), or deep surgical site infection (8). No PJK was observed in any of the patients with L5 PSO. CONCLUSIONS: PSO at the level of L4 or L5 remains a challenging technique but with an acceptable rate of complications and revisions. It enables correction of fixed sagittal malalignment in ASD patients with a globally satisfactory outcome. In comparison with L4 PSO, L5 PSO patients did not show PJK as a mechanical complication. Distal lumbar PSO at the level of L5 may represent one of the factors that may help preventing the proximal junctional kyphosis complication.

Specific sagittal alignment patterns are already present in mild adolescent idiopathic scoliosis.

PURPOSE: The complex three-dimensional spinal deformity in AIS consists of rotated, lordotic apical areas and neutral junctional zones that modify the spine's sagittal profile. Recently, three specific patterns of thoracic sagittal 'malalignment' were described for severe AIS. The aim of this study is to define whether specific patterns of pathological sagittal alignment are already present in mild AIS. METHODS: Lateral spinal radiographs of 192 mild (10°-20°) and 253 severe (> 45°) AIS patients and 156 controls were derived from an international consortium. Kyphosis characteristics (T4-T12 thoracic kyphosis, T10-L2 angle, C7 slope, location of the apex of kyphosis and of the inflection point) and sagittal curve types according to Abelin-Genevois were systematically compared between the three cohorts. RESULTS: Even in mild thoracic AIS, already 49% of the curves presented sagittal malalignment, mostly thoracic hypokyphosis, whereas only 13% of the (thoraco) lumbar curves and 6% of the nonscoliosis adolescents were hypokyphotic. In severe AIS, 63% had a sagittal malalignment. Hypokyphosis + thoracolumbar kyphosis occurred more frequently in high-PI and primary lumbar curves, whereas cervicothoracic kyphosis occurred more in double thoracic curves. CONCLUSIONS: Pathological sagittal patterns are often already present in curves 10°-20°, whereas those are rare in non-scoliotic adolescents. This suggests that sagittal 'malalignment' patterns are an integral part of the early pathogenesis of AIS.

Revisiting thoracic kyphosis: a normative description of the thoracic sagittal curve in an asymptomatic population.

PURPOSE: Thoracic kyphosis (TK) remained in the shadow of lumbar lordosis. Based on Berthonnaud and Roussouly segmentation, TK is divided into two arches: upper TK (UTK) and lower TK (LTK). The purpose of this study is to propose a normative description of the TK arches in an asymptomatic adults' population and their correlation with spinal and pelvic parameters. METHODS: This is an observational study performed on asymptomatic healthy Caucasians volunteers aged between 18 and 45 years. Each patient had a standardized standing biplanar full spine X-rays. Using KEOPS®, sacropelvic parameters and global spinal parameters (LL, TK) as well as the inflexion point location were measured. The upper lumbar lordosis angle (ULL) as well as LTK and UTK was calculated. Patients were classified according to Roussouly morphotypes of normal spine. RESULTS: A total of 373 adults (F/M = 1.4/1) were enrolled with mean age of 27 years. Mean UTK averaged 25.8°, while mean LTK averaged 19.8° (p < 0.001). UTK angle values were statistically the same in the five different Roussouly spinal shapes (p > 0.05), while LTK values were variable among different Roussouly spine subtypes (p < 0.05). Finally, TK showed the highest correlation with the LL mainly with the ULL (Pearson = 0.66). CONCLUSION: In asymptomatic young adults, thoracic kyphosis is composed by two unequal arches, a stable UTK and a variable LTK, with an apex around T8 and T9 vertebra, depending on the spinal morphotype according to Roussouly classification. This should be taken into consideration when analyzing spine sagittal compensation and preparing corrections to minimize risk of mechanical complications.

Description of the sagittal alignment of the degenerative human spine.

PURPOSE: To present the description of sagittal alignment of the degenerative human spine and its possible evolution. MATERIALS AND METHODS: This is a retrospective observational study of degenerative evolution in spinal alignment in low back pain patients. Full spine EOS® sagittal X-rays were analyzed, and pelvic and spinal parameters were measured. Spinal shapes were classified on the hypothesis that the possible sagittal shapes of degenerative spine would be divided into four categories: "classical" Roussouly types 1-4, anteverted types (PT ≤ 5), retroverted types (PT ≥ 25) and kyphotic types. RESULTS: A total of 331 patients (280 women and 51 men) were included. "Classic" types 1-4 represented the majority in this cohort (71.9%). Retroverted types made the second most common category with 20.8% of the cohort. Kyphosis group (lumbar and global) make only 5.8% of this cohort, while anteverted group make the lowest incidence (1.5%). Retroverted type 2 with thoracic kyphosis should be considered a separate type and made 1.5% of this cohort. Two theoretical subtypes, retroverted type 1 and type 4 were not found. CONCLUSIONS: This is the first description of degenerative spine disease based on its shape and based on the classification of the normal variation in the sagittal alignment of the human lumbar spine described by Roussouly. Eleven types, divided into classical types, anteverted types, false shapes (retroverted) and kyphotic shapes, are described and an evolution pathway is proposed. An evaluation of surgical results in order to propose a treatment algorithm based on this classification should follow. LEVEL OF EVIDENCE: Level IV cross sectional observational study.

Proximal junctional kyphosis in adult scoliosis: comparison of four radiological predictor models.

OBJECTIVE: The objective of this retrospective study is to identify the best immediate postoperative radiological predictors for the occurrence of proximal junctional kyphosis (PJK). Four proposed methods will be explored. METHODS: A homogeneous database of adult scoliosis from multiple centers was used. Patients with whole spine X-rays at the required follow-up (FU) periods were included. Spinal and pelvic parameters were measured and calculated to compare four predictive methods: Method 1: assessment of the global sagittal alignment (GSA); Method 2: restoration of the theoretical values of lumbar lordosis (LL) and thoracic kyphosis (TK) according to pelvic incidence (PI); Method 3: evaluation of TK + LL, and Method 4: restoration of the apex of sagittal LL to its theoretical values according to various spine shapes in Roussouly Classification. PJK occurrence was assessed at the last FU radiograph. RESULTS: 250 patients were included; mean age was 56.67 years and mean FU was 2.5 years. PJK occurred in 25.6% of cases. PJK occurred in 19.9% in patients with a GSA <45° and in 29.9% where GSA >45° (p = 0.04, OR = 1.71). Restoring the sagittal apex of the LL to its theoretical values according to PI deceased PJK to 13.5% compared to 38.9% in the other cases (p = 0.01, OR = 4.6). The two other described methods (2 and 3) were not significant predictors. DISCUSSION: The comparison between the four predictive methods showed that a GSA >45° and restoration of sagittal apex of lordosis according to PI, were the most predictive methods for PJK in ASD. The latter had a higher predictive value. Our findings could prove useful in effective preoperative planning in ASD surgery to reduce PJK rates. LEVEL OF EVIDENCE: Level IV.

Instrumented L5-S1 interbody graft with IFUSE implant using the reverse Bohlman technique.

BACKGROUND: In case of high sacral slope, anterior lumbosacral fusions can be performed by retroperitoneal or transperitoneal approach using a reversed Bohlman technique with an autologous corticocancellous fibular graft. The use of a trans-lumbosacral implant can avoid the iatrogenic effects but currently, there is no implant specifically designed for this fusion technique. Could the IFUSE implant from SI BONE replace a fibular graft to avoiding the iatrogenic effect induced by sampling during a Reverse Bohlman technique? PATIENTS AND METHODS: We present the case of a 38-year-old woman with L5S1 interbody pseudarthrosis after posterior fixation for grade 2 L5-S1 spondylolisthesis with isthmic lysis of L5, and that of a 69-year-old woman who underwent a posterior T4 fusion to the pelvis for degenerative scoliosis. Both required a trans-lumbosacral instrumented fusion via an anterior approach using the reverse Bohlman technique. Surgical technique was described. RESULTS: There were no perioperative or postoperative complications. At 6 months, the patients reported a decrease in lumbar and radicular symptomatology. There were no infectious, neurological or vascular complications. CT-scans confirmed the good position and stability of the IFUSE implant. DISCUSSION: We present an innovative interbody grafting technique adapted to spines with high pelvic incidence. The surgical technique is safe, minimally invasive, and reduces surgical iatrogeny. The short and medium-term results are positive but require longer-term follow-up and a larger cohort.

Quantifying the Spinal Lordosis Ratio Unique to the Type of Spinal Sagittal Alignment in a Normal Population.

STUDY DESIGN: Data collection of radiological parameters in non-pathological adult spines. OBJECTIVES: Establishing a baseline database for measurements of the spinal lordosis ratio between upper and lower arcs of the lumbar spine unique to each type of spine described by Roussouly's classification. Illustrating the importance of correct rationing of the upper and lower arcs. METHODS: Standardised standing true lateral plain radiographs of the spine (including base of skull and proximal femurs) from 373 adult volunteers were obtained. Exclusion criteria : any history of disease involving the spine, pelvis, hips or lower limbs. Incidental detection of any spinal deformity on radiography also excluded further participation in this study. Sacro-pelvic parameters data collected : Pelvic Incidence (PI), Pelvic Tilt (PT), Sacral Slope (SS), location of Inflection Point, number of vertebras in the spinal lordosis and type of Roussouly's spine. Values of upper arc, lower arc and spinal lordosis ratio (SLR) was determined. RESULTS: Bivariate analysis revealed statistically significant (P < .0001) correlation between the types of sagittal spinal alignments based on Roussouly's classification and the SLR. Type 1: SLR .76 ± .17, Type 2: SLR .60 ± .18, Type 3 with anteverted pelvis: SLR .53 ± .11, Type 3: SLR .49 ± .12, Type4: SLR .41 ± .11. CONCLUSION: With this data we are able to quantify the ratio of lumbar lordosis unique to each type of Roussouly's spine. It functions as a guide when planning lumbar spine surgeries in order to restore the SLR correctly and thus prevent post-op complications such as proximal junction kyphosis.

Very long-term clinical and radiographic outcomes after posterior spinal fusion with pedicular screws for thoracic adolescent idiopathic scoliosis.

PURPOSE: To report radiographic and functional outcomes, with an average follow-up of 20 years, of adolescents treated surgically for thoracic idiopathic scoliosis by hybrid construct using only pedicular screws for the distal fixation. METHODS: We retrospectively reviewed 109 patients. Radiographic data were evaluated on fullspine radiographs (Cobb angle, pelvic incidence, sacral slope, pelvic tilt, thoracic kyphosis, lumbar lordosis). Clinical data were evaluated with ODI, SF-12, SRS-30 and Analog Pain Scale. Disc height and listhesis below the arthrodesis were measured. RESULTS: We analyzed 90 women and 19 men with a mean age of 16.9 y.o. at surgery. Radiographic data were assessed for 46 patients after 17.4 years. Mean preoperative Cobb angle was 58°, mean correction 40.1% with 5.3° of loss at final FU. Lumbar lordosis and thoracic kyphosis increased significantly at last FU. Degenerative changes below the arthrodesis were reported in 5 cases. Clinical data were assessed for 42 patients after 19.9 years: SRS-30 3.8; ODI 12.3%; SF-12 PCS 48.6 and MCS 46. Low back pain was reported in 69% of cases with low intensity (3.1). The lowest instrumented vertebrae did not influence significantly the functional outcome. CONCLUSIONS: The correction of thoracic AIS with lumbar or thoracolumbar pedicle screw instrumentation provides good radiological and clinical outcomes at very long term. The reduction in the coronal plane is stable; the HRQoL is quite as good as the general population. The degenerative evolution below remain relatively rare, therefore global sagittal balance is not modified.

Early versus delayed corpectomy in thoracic and lumbar spine trauma. A long-term clinical and radiological retrospective study.

AND BACKGROUND DATA: Many authors have demonstrated the necessity of reconstruction of the anterior column in spinal trauma with vertebral body collapse or nonunion. There is no publication comparing the result depending on the time between trauma and anterior reconstruction of the vertebral body. OBJECTIVE: To compare long-term clinical and radiological results between early and late anterior vertebral body reconstruction with expandable cages in patients with thoracic and lumbar spine trauma. HYPOTHESIS: An early anterior reconstruction of thoracolumbar fractures provides better clinical and radiological outcomes than a delayed one. MATERIALS AND METHODS: A retrospective clinical study was carried out with 44 consecutive patients with injuries of the thoracic and lumbar spine treated operatively with combined posterior stabilization and anterior reconstruction with an expandable implant for vertebral body replacement. All patients were evaluated with EOS full-spine radiograph and CT-scan. The mean follow-up was 5.1 years. Clinical result was evaluated with ODI, SF12, VAS back pain, return to work and sport. Radiological result was evaluated with regional kyphosis angle (RKA) evolution, fusion rate and sagittal alignment. In Group A, twenty-nine patients underwent an early anterior reconstruction within 3 weeks after trauma. The indication of vertebral body reconstruction was placed after post-operative CT-scan for a Mc Cormack score≥7. In Group B, fifteen patients underwent a late anterior reconstruction after diagnosis of nonunion by the combination of pain and CT-scan after 1 year. RESULTS: Clinical scores and scales were significantly better for patients operated early in Group A. Return to work and activities were significantly more important in Group A too. The mean RKA correction with posterior reduction was 9.3°. The secondary anterior approach permit to reduce 2.9° more. At last follow-up, the loss of reduction was 4.3°. There was no significant difference between groups for those results. No difference in fusion rate was observed between groups. There was no significant difference between groups in the sagittal alignment excepted for SVA that was higher for Group B while remaining under a normal value of 50mm. CONCLUSION: Early anterior vertebral body reconstruction for fractures gives better clinical results than delayed reconstruction for patients with diagnosis of nonunion in patients with thoracic and lumbar spine trauma. Moreover, the shorter the time from trauma to operation, the better the sagittal reduction of kyphosis. The use of expandable titanium cage is a good way to perform and maintain this reduction. LEVEL OF EVIDENCE: IV, retrospective study.

L5 incidence: an important parameter for spinopelvic balance evaluation in high-grade spondylolisthesis.

BACKGROUND: In high-grade spondylolisthesis (HGSPL), the pelvic incidence (PI) is not a reliable measurement because of doming of the sacrum. Measurement of L5 incidence (L5I) was described as a tool to measure pelvic morphology in HGSPL and for surgical follow-up. OBJECTIVE: We aimed to evaluate L5I in HGSPL and its relationship to other spinopelvic parameters. STUDY DESIGN: A retrospective study of a cohort of 184 patients with HGSPL was carried out. METHODS: Whole spine radiographs were analyzed for PI, pelvic tilt (PT), sacral slope, lumbar lordosis (LL), L5I, L5 tilt (L5T), L5 slope, lumbosacral kyphosis, and slip percentage. Statistical analysis and correlation were made (Pearson correlation test; p<.05). In accordance to Cohen, statically significant correlation were considered strong if R>0.5, moderate if 0.3