Postoperative Lumbar Lordosis Research Articles

61. ALIF vs TLIF for isthmic spondylolisthesis: differences in radiographic outcomes

BACKGROUND CONTEXT Patients with a diagnosis of isthmic spondylolisthesis have higher sacral slope, pelvic tilt, pelvic incidence and lumbar lordosis compared to patients without isthmic spondylolisthesis. Several fusion techniques have been used to treat isthmic spondylolisthesis in adults, including anterior lumbar interbody fusion (ALIF) and transforaminal interbody fusion (TLIF). Compared to other fusion techniques, ALIF has shown better sagittal alignment outcomes, particularly restoration of segmental lordosis. PURPOSE The purpose of this study was to evaluate which fusion technique provides the better radiological outcome for adult lumbar isthmic spondylolisthesis. STUDY DESIGN/SETTING This study was a retrospective analysis of prospectively collected data from a single, high-volume academic medical center. PATIENT SAMPLE Patients who underwent lumbar fusion for isthmic spondylolisthesis from 2014 to 2019 were included in the analysis. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, presented with a tumor or infection, or underwent revision surgery. OUTCOME MEASURES Preoperative and postoperative radiographic parameters were collected including sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lumbar lordosis, and the vertebral slip percentage. METHODS Patient and surgical characteristics including age, gender, smoking status, body mass index (BMI), Charlson Comorbidity Index (CCI), number of levels decompressed and number of levels fused were collected. Preoperative and final radiographic outcomes were obtained from an institutional electronic medical record. For analysis, patients were divided into two groups based on surgical technique: combined anterior fusion with posterior stabilization (ALIF-PLDF) or anterior and posterior fusion through a posterior approach (TLIF). RESULTS A total of 101 patients were included in final analysis, with 52 patients in the ALIF-PLDF group and 49 patients in the TLIF group. Mean age was greater in the TLIF group (p=0.017). Patients in the TLIF group were more likely to have a history of smoking (p=0.008), to have a greater CCI score (p=0.003), and to have higher number of levels decompressed. On analysis of radiographic parameters, preoperative sacral slope was higher in in the ALIF-PLDF group than the TLIF group (p=0.071). Postoperative overall lumbar lordosis was lower in the TLIF group (p=0.036). Postoperative segmental lumbar lordosis and the delta value for segmental lumbar lordosis were both lower in the TLIF group (p=0.030 and p=0.001). The TLIF group had a significant increase in PI-LL mismatch (p=0.032). Both groups had significant decrease in vertebral slip percent (p CONCLUSIONS Our data highlights that patients undergoing ALIF have a significant increase in segmental lordosis from their preoperative baseline. Interestingly, patients undergoing TLIF have significantly less postoperative change in segmental lumbar lordosis when compared to ALIF. When treating patients with isthmic spondylolisthesis, the ALIF approach has benefits not only in its capacity to restore segmental lordosis, but also by providing significant reduction in vertebral body slip. Our results suggest that, when compared to the TLIF approach, ALIF may be associated with better outcomes in terms of critical radiographic parameters. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

202. Hyperlordotic anterior interbody use without superior articulating process resection has an increased risk of Iiatrogenic neurological injury single level circumferential fusion

BACKGROUND CONTEXT Hyperlordotic (>20°) anterior interbody cages (HAI) may be utilized in anterior-posterior fusion (AP-F) in efforts to improve alignment. However, significant increase in segmental lordosis (SL) in HAI without superior articulating process resection (SAP) may result in foraminal stenosis and nerve root compression causing neurological deficits and radiculopathy. Additionally, HAI with SAP may increase SL without concomitant increase in lumbar lordosis (LL). PURPOSE Assess whether HAI without SAP in APF causes increased neurological complications. STUDY DESIGN/SETTING Single-center retrospective cohort study PATIENT SAMPLE A total of 158 patients undergoing single level APF were included, of which 73 had HAI placed and 85 had SAI placed. OUTCOME MEASURES Outcomes measures included radiographic analysis of pre- and postoperative LL and SL. Perioperative neurological complications were measured including new radiculopathy, iatrogenic motor deficit and malpositioned instrumentation or compressive hematoma causing deficit. Returns to OR within 30 or 90 days were measured including return for foraminal decompression, instrumentation revision, hematoma evacuation, and irrigation and debridement. METHODS Patients undergoing primary, single level, APF without SAP resection over a 5-year period were included. Patients were classified as HAI or SAI. Outcomes measures included perioperative neurological complications, returns to OR, pre- and postoperative LL and SL. Demographic, procedural and perioperative outcomes were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at p RESULTS A total of 158 patients (73 HAI, 85 SAI) were included. Age, gender, BMI and CCI were similar between groups. HAI without SAP resulted in significantly larger change in SL (9.84±5.84 vs 7.32±5.02 deg, p=0.001), without a significantly larger change in LL (8.16±1.11 vs 11.5±1.69 deg; p=0.641) compared with SAI. HAI without SAP increased overall incidence of neurological deficit (13.69% vs 3.53%; p=0.012), iatrogenic new cases of radiculopathy (10.95% vs 3.53%; p=0.045), and iatrogenic neurological motor deficit (13.69% vs 3.53%; p=0.012). Regression analysis demonstrated that increasing cage lordosis greater than 20° is an independent risk factor for neurological complications (p=0.046), as is higher preop SL (p=0.022). There were no significant differences in returns to OR. CONCLUSIONS We caution HAI implantation without SAP resection due to increased neurological complications from iatrogenic nerve root injury without the benefit of significantly improving LL correction. Use of HAI without SAP resection in single level APF should not be standard practice due to risk of neurological complications. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P124. The lordosing effect of the prone transpsoas technique: preliminary results of a multicenter experience

BACKGROUND CONTEXT The lateral lumbar interbody fusion (LLIF) is a proven and effective technique to treat a vast range of lumbar disorders. Nevertheless, the LLIF is also burdened by some problems, such as postoperative neurological deficits, small segmental index level lordosis, and the frequent necessity to reposition the patient to instrument posteriorly. A new approach to LLIF was devised to solve or reduce some of the drawbacks associated with the lateral approach. Its main difference from other lateral approaches is in positioning the patient in the prone position, which might lead to improved intradiscal lordosis and overall sagittal alignment. PURPOSE Report early radiographic results from LLIF using the prone transpsoas technique (PTP). STUDY DESIGN/SETTING Retrospective, non-comparative, non-randomized analysis of a prospectively collected database from four separate centers. PATIENT SAMPLE Patients include those who underwent PTP at four participating centers. Inclusion criteria: Signed consent, underwent any number of PTP levels, with complete perioperative radiological outcomes. Exclusion: Incomplete radiological data, procedures that included anterior column release (ACR) or that otherwise had a resected anterior longitudinal ligament. OUTCOME MEASURES Preoperative and postoperative pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL: L1-S1), pelvic mismatch (PI-LL), and index-level segmental lordosis. METHODS Patient characteristics were collected through a retrospective analysis of radiological data and measured with special computer software. For continuous variables, mean and 95% confidence were reported, and for dichotomous variables, counts of values and percentages were reported. Student's T-test was performed to compare continuous variables and Fisher's Exact Test was used to compare dichotomous variables. Calculations were performed using Excel. RESULTS Forty (40) patients undergoing PTP at 59 levels were included in the study. Twenty-nine (29) underwent single-level, eight underwent two-level, three underwent three-level, and one underwent four-level PTP. Mean index-level segmental lordosis increased from 7,2° (± 7.3; 95% CI 5,3-9,1) to 14,0° (± 6,8; 95% CI 12,2 – 15,7) (p CONCLUSIONS The LLIF prone transpsoas technique is feasible and relies on prone patient positioning, an advantage for improving lordosis and enabling the surgeon to supplement with posterior procedures. Preliminary results show significant lordosis improvement even without anterior longitudinal ligament release. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P78. Spinopelvic sagittal imbalance as a risk factor for fracture type of proximal junctional failure after posterior instrumented fusion

BACKGROUND CONTEXT Postoperative fracture of the upper instrumented vertebrae (UIV) is thought to be a fracture type of proximal junctional failure (PJF), which usually needs for proximal extension of the fusion. Global sagittal imbalance has been considered as a potential risk factor to develop PJF. Spinopelvic parameters, such as the pelvic incidence (PI) angles, sacral slope (SS) angles, and pelvic tilt (PT) angles have been recognized to affect overall sagittal balance. PURPOSE To investigate the influence of spinopevic parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), and proximal local kyphosis (PLK) angle on the development of fracture type of PJF after posterior instrumentation for degenerative lumbar diseases. STUDY DESIGN/SETTING A retrospective case-control cohort study. PATIENT SAMPLE Ninety-six patients. OUTCOME MEASURES Clinical outcomes were evaluated with Oswestry Disability Index (ODI) and the visual analogue scale (VAS) for leg and back pain. The medical conditions were reviewed using the weighted Charlson Comorbidity Index (CCI), bone mineral density (BMD) with T score, and body mass index (BMI). Radiographic parameters such as coronal Cobb's angle, PI, SS, PT, LL, and PLK were measured for comparison. The prevalence of osteoporotic compression fractures (OVFx), PI-LL, and score for spinopelvic realignment achievement were calculated. METHODS Between January 2007 and December 2017, patients underwent posterior instrumented fusion were reviewed. This was a retrospective 1:3 matched case-control study. Twenty-four patients who had undergone revision surgery for UIV fracture of PJF after posterior instrumented fusion were categorized as the study group. As a control group, 72 age-, sex-, and surgical level- matched patients who had undergone posterior instrumented fusion during the same period, had no development of UIV fracture of PJF for more than two years. RESULTS Before surgery, the study group already had more comorbidities (CCI: 1.75 ± 0.90 vs 1.22± 0.61, p= 0.002), poorer bone density (T score: -3.41 ± 1.12 vs -1.81± 0.83, p= 0.001), significant higher prevalence of OVFx (46% vs 18%, p = 0.006) than the control group. In terms of preoperative radiographic parameters, the study group had significantly lower LL (22.85o ± 17.15o vs 31.66o ± 15.10o, p= 0.030), SS (22.69o ± 10.69o vs 28.34o ± 12.66o, p= 0.043), and significantly higher PLK (2.98o ± 9.23ovs -9.20o ± 12.89o, p CONCLUSIONS In addition to osteoporoitc bone quality, pre- and postoperative lower LL, and higher PI-LL/PLK were also significantly associated with development of UIV fracture in PJF. Therefore, obtaining appropriate LL and correcting PLK should be done at surgery to improve spinopelvic sagittal imbalance. The results suggest that the achievement of appropriate LL and PI-LL prevents instrumented fracture of PJF after posterior instrumented fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Incidence of Cranial Adjacent Segment Disease after Posterior Lumbar Interbody Fusion Using the Cortical Bone Trajectory Technique for the Treatment of Single-Level Degenerative Lumbar Spondylolisthesis; More than a 2-Year Follow-Up

Introduction Posterior lumbar interbody fusion (PLIF) is a widely used effective, safe, and established treatment for degenerative spinal disorders. Adjacent segment disease (ASD) is one of the serious concerns governing the clinical results following spinal fusion surgery. Cortical bone trajectory (CBT) is an alternative and less-invasive technique for lumbar pedicle screw placement. Its unique medial and caudal entry point has the potential to prevent an iatrogenic facet joint violence leading to the ASD; however, the incidence of ASD following PLIF using the CBT technique (CBT-PLIF) remains unknown. Methods Among patients surgically treated with CBT-PLIF in our institute, 52 consecutive patients (13 males, 39 females) with single-level degenerative lumbar spondylolisthesis (DLS) who were followed up for at least 24 months were exclusively enrolled. Their clinical and radiological features, including the incidence of radiographical and symptomatic ASD and significantly associated factor for the developing radiographical ASD, were retrospectively measured. Results In the present study, we could confirm significant neurological improvement and reduction of the spondylolisthesis with mean follow-up period of 43 months. Radiographical and symptomatic ASD was observed in 14 (27%) and 2 (3.8%) cases, respectively. We compared these two groups and found that the latest lumbar lordosis was significantly different between the two groups, but not in age, body mass index, and Japan Orthopaedic Association score. Two patients with symptomatic ASD required additional surgical treatment around 1 year following the initial surgery. Conclusions The present study, even though it is preliminary, revealed that CBT-PLIF can achieve a neurological improvement and an effective reduction of spondylolisthesis for the treatment of single-level DLS. The CBT technique is capable of reducing the incidence of ASD compared with the traditional technique; however, we must keep in mind that appropriate postoperative lumbar lordosis should be achieved. Larger, longer-term follow-up studies are required to elucidate the clinical output of CBT-PLIF.

Incidence, Risk Factors, and Prevention Strategy for Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery.

Introduction Proximal junctional kyphosis (PJK) is an acute complication of adult spinal deformity (ASD) surgery and may require re-operation because of proximal junctional failure (PJF). PJK causes and prevention strategies remain unknown. This study aimed to investigate the differences in the backgrounds of patients with PJK, compared to those without PJK, in ASD surgery. Methods We included data from 86 patients who underwent ASD surgery between 2012 and 2018. There were 40 patients (46.5%) with PJK; 46 patients did not have PJK until the last follow-up. We evaluated patient demographics, clinical outcomes, and radiographic parameters, such as Cobb angle and spinopelvic parameters on standing X-ray films, in each group. Results There was no significant difference in patient demographics, clinical outcomes, or preoperative radiographic parameters. Postoperative pelvic incidence minus lumbar lordosis (PI-LL) and pelvic tilt (PT) were significantly lower in the PJK group, and thoracic kyphosis (TK) was higher. The cutoff values were 34.5° for TK, 0.5° for PI-LL, and 15.5° for PT. Other radiographic parameters were not significantly different. PJF developed in seven patients (17.5%) in the PJK group. PJF patients had significantly older age, higher postoperative TK, higher postoperative proximal junctional Cobb angle (PJA), more changes between pre- and postoperative PJA, and lower satisfaction scores on the Scoliosis Research Society Outcomes Questionnaire (SRS-22 satisfaction) than non-PJF patients in the PJK group. Conclusions One risk factor for PJK was lower postoperative PI-LL that was 0° or less. In ASD surgery, the most critical factor in a PJK prevention strategy is to obtain a postoperative LL adjusted by PI, which is >0°.

The association between lower Hounsfield units of the upper instrumented vertebra and proximal junctional kyphosis in adult spinal deformity surgery with a minimum 2-year follow-up.

Patients undergoing long-segment fusions from the lower thoracic (LT) spine to the sacrum for adult spinal deformity (ASD) correction are at risk for proximal junctional kyphosis (PJK). One mechanism of PJK is fracture of the upper instrumented vertebra (UIV) or higher (UIV+1), which may be related to bone mineral density (BMD). Because Hounsfield units (HUs) on CT correlate with BMD, the authors evaluated whether HU values were correlated with PJK after long fusions for ASD. The authors performed a retrospective study of patients older than 50 years who had undergone ASD correction from the LT spine to the sacrum in the period from October 2007 to January 2018 and had a minimum 2-year follow-up. Demographic and spinopelvic parameters were measured. HU values were measured on preoperative CT at the UIV, UIV+1, and UIV+2 (2 levels above the UIV) levels and were assessed for correlations with PJK. The records of 127 patients were reviewed. Fifty-four patients (19 males and 35 females) with a mean age of 64.91 years and mean follow-up of 3.19 years met the study inclusion criteria; there were 29 patients with PJK and 25 patients without. There was no statistically significant difference in demographics or follow-up between these two groups. Neither was there a difference between the groups with regard to postoperative pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), PI minus LL (PI-LL), thoracic kyphosis (TK), or sagittal vertical axis (SVA; all p > 0.05). Postoperative pelvic tilt (p = 0.003) and T1 pelvic angle (p = 0.014) were significantly higher in patients with PJK than in those without. Preoperative HUs at UIV, UIV+1, and UIV+2 were 120.41, 124.52, and 129.28 in the patients with PJK, respectively, and 152.80, 155.96, and 160.00 in the patients without PJK, respectively (p = 0.011, 0.02, and 0.018). Three receiver operating characteristic (ROC) curves for preoperative HU values at the UIV, UIV+1, and UIV+2 as a predictor for PJK were established, with areas under the ROC curve of 0.710 (95% CI 0.574-0.847), 0.679 (95% CI 0.536-0.821), and 0.681 (95% CI 0.539-0.824), respectively. The optimal HU value by Youden index was 104 HU at the UIV (sensitivity 0.840, specificity 0.517), 113 HU at the UIV+1 (sensitivity 0.720, specificity 0.517), and 110 HU at the UIV+2 (sensitivity 0.880, specificity 0.448). In patients undergoing long-segment fusions from the LT spine to the sacrum for ASD, PJK was associated with lower HU values on CT at the UIV, UIV+1, and UIV+2. The measurement of HU values on preoperative CTs may be a useful adjunct for ASD surgery planning.

Estimation of the ideal correction of lumbar lordosis to prevent reoperation for symptomatic adjacent segment disease after lumbar fusion in older people

BackgroundSymptomatic adjacent segment disease (ASDis) is a major complication following spinal fusion. Sagittal spinopelvic imbalance may contribute to the development of ASDis. However, the exact ideal correction of lumbar lordosis (LL) is unknown for different ages of people to prevent ASDis. The purpose of this study was to estimate the ideal correction of LL required to prevent symptomatic ASDis requiring revision surgery in patients of various ages, and to determine the radiographic risk factors for ASDis.Methods468 patients who underwent lumbar fusion between January 2014 and December 2016, were enrolled in the present study. The patients were classified into the ASDis and N-ASD group. These two matched groups were compared regarding surgery-related factors and radiographic features. Multivariate logistic regression analysis was used to evaluate the risk factors for ASDis.ResultsSixty-two patients (13.25%) underwent reoperation for ASDis during a mean follow-up duration of 38.07 months. Receiver operating characteristic curve analysis showed that the postoperative LL - preoperative LL (△LL) cutoff value was 11.7°for the development of ASDis. Logistic regression analysis revealed that the risk factors for symptomatic ASDis were a smaller LL angle, △LL > 12°, and PI-LL > 10° (p < 0.05). For patients > 60 years, the incidence of ASDis was higher in patients with a LL correction of ≥10° and a lumbar-pelvic mismatch (PI-LL) of > 20°.ConclusionsThe significant predictors of the occurrence of ASDis were a smaller LL angle, △LL > 12°, and PI-LL > 10°. However, in patients older than 60 years, the incidence of ASDis after lumbar fusion was higher in those with a LL correction of ≥10° and PI-LL of > 20°. More attention should be paid to patient age and the angle of correction of LL before lumbar fusion.

Comparison of surgical correction rates between titanium and cobalt-chrome-alloy as rod materials in adolescent idiopathic scoliosis

Numerous biomechanical studies comparing titanium (Ti) and cobalt-chrome-alloy (CCM) rods are described in the literature. However, there is a dearth of literature comparing the two rod materials in adolescent idiopathic scoliosis (AIS). Therefore, the purpose of this study is to compare the correction rates of Ti and CCM rods in the treatment of AIS with double major curves. We enrolled 45 patients with AIS who underwent surgery between 2009 and 2012. We divided patients into two groups, Group A (n = 29) treated with six-millimeter Ti rods and Group B (n = 16) treated with six-millimeter CCM rods. The rod-derotation maneuver was used for correction. We measured pre- and postoperative indices of coronal alignment (Cobb’s angle, coronal balance, T1-tilt, clavicle angle) and sagittal alignment (sagittal vertical axis, thoracic kyphosis, lumbar lordosis). In our study, there were no significant differences between the two groups with respect to demographics or curve characteristics (P > 0.05). In Group A, thoracic and lumbar curvature correction rates were 71.2% and 66.8% respectively, and in Group B they were 71.2% and 73.3%, respectively (P = 0.664 and 0.09). There were no significant differences between the two groups in coronal or sagittal factors (P > 0.05) except for greater postoperative lumbar lordosis in the CCM group (P < 0.001). In conclusion, Ti and CCM rods showed similar correction rates in the sagittal and coronal planes for the surgical correction of AIS with double major curves. Biomechanical studies of Ti and CCM rods in vitro is different in biological condition.

The prone transpsoas technique: preliminary radiographic results of a multicenter experience.

The lateral lumbar interbody fusion (LLIF) is a safe and effective technique to treat a vast range of lumbar disorders. However, the technique is also burdened by some problems. A new approach to the lateral lumbar interbody fusion was devised to solve or reduce some of the problems regarding the lateral approach. Its principal difference from the standard LLIF relies on positioning the patient in a prone decubitus, which might lead to an increase in the intradiscal lordosis. A retrospective, multicentric, non-randomized study to evaluate segmental and regional lordosis following prone transpsoas (PTP) approach to LLIF. All patients undergoing prone transpsoas surgery at the involved institutions were included. Patients with low-quality images not allowing the measurements of the required spinopelvic parameters were excluded. Measurements included pre- and postoperative index-level segmental lordosis, lumbar lordosis, pelvic incidence, and pelvic tilt. Thirty-two (32) patients were included in the study, in which 23 underwent single-level, six (6) underwent two-level, Two (2) underwent three-level, and one underwent four-level PTP. Mean index level segmental lordosis increased from 8.7° to 14.8°(p < 0.001); lumbar lordosis (L1-S1) increased from 42.1° to 45.8° (p = 0.11), although after excluding an outlier value L1-S1 lordosis results were 41.9° pre-op to 46.7° post-op (p = 0.003). Twenty-two (22) patients had a pre-op PI-LL mismatch of 10° or more, while at the postoperative visit, only 12 patients had a mismatch outside of 10° (p = 0.01). The prone transpsoas technique is feasible and is associated with a significant gain of segmental lordosis and correction of spinopelvic alignment parameters.

Choice of osteotomy methods for old thoracolumbar osteoporotic fracture with kyphosis

To investigate the clinical outcome of single or double-segment pedicle subtraction osteotomy (PSO) for the treatment of old thoracolumbar osteoporotic compression fractures with kyphosis. The clinical data of 26 patients with old thoracolumbar osteoporotic compression fractures with kyphosis who underwent surgery from January 2015 to June 2017 were retrospectively analyzed. There were 12 males and 14 females, aged from 58 to 72 years old with an average of 65.6 years. The time interval from fracture to surgery was (8.2±1.5) years. According to different surgical methods, the patients were divided into single-segment PSO group (group A) and double-segment PSO group(groupB). The perioperative data, preoperative and postoperative imaging data and postoperative complications were recorded, and the Oswestry Disability Index (ODI) and visual analogue scale (VAS) were used before and after surgery to evaluate the clinical effect. All patients were followed up for 6-24 months with an average of 14.5 months. There was a statistically significant difference in operation time and intraoperative blood loss between the two groups (P<0.05). There was no significant difference in total drainage volume and length of hospital stay (P>0.05). The postoperative correction angle of the single segment PSO group was (33.3± 9.4) ° with the correction rate of 85.3% and the double segment PSO group was (41.0±13.5) ° with the correction rate of 92.7%, and there was statistical significance between two groups (P<0.05). There were no significant differences in postoperative lumbar lordosis (LL), sagittal vertical axis (SVA), and ODI, VAS between two groups (P>0.05). One case of cone injury occurred in the single-segment PSO group and recovered after treatment. There were no complications of spinal cord injury in the double segment group. Loose screws occurred during surgery in three patients in the single-segment PSO group and one patient in the double-segment PSO group (P<0.05). All 4 patients were re inserted with screws after using bone cement to reinforce the nail pathway. There were no complications such as anterior spinal vascular and nerve damage or osteotomy unfusion. Both single-segment PSO and double-segment PSO can achieve good orthopedic and clinical effects in the treatment of old thoracolumbar osteoporotic fractures with kyphosis. For patients with correction angles greater than 40° , the double-segment PSO provides a better correction angle and is safer, but it is with longer operation time and more intraoperative bleeding.

Vertebral Bone Quality Score and Postoperative Lumbar Lordosis Associated with Need for Reoperation After Lumbar Fusion

Poor bone quality is a known risk factor for hardware failure and adjacent segment disease after lumbar fusion. One new method of analyzing bone quality is the vertebral bone quality (VBQ) score, which can be obtained from preoperative lumbar magnetic resonance imaging (MRI) scans. We decided to evaluate whether patients' VBQ scores were associated with reoperation after lumbar fusion. We queried records of patients who underwent elective lumbar fusion for degenerative conditions between 2012 and 2017. Patients who required reoperations after lumbar fusions because of symptomatic hardware failure or adjacent segment disease were combined into a case group and compared with a matched control group. Of the 46 patients who underwent elective lumbar fusions and required reoperation, 30 met the inclusion criteria. A 2:1 control group of 60 individually age-, body mass index-, and sex-matched patients who did not require reoperation was then created. The reoperation group had significantly lower degrees of postoperative lumbar lordosis. There were no significant differences regarding other spinopelvic parameters, adjacent Pfirrmann scores, or dual energy x-ray absorptiometry (DXA) T scores. There was, however, a significant difference in VBQ scores between the groups, with the reoperation group having a higher VBQ score. This study found that bone quality, according to the VBQ score rather than the DXA T score, is an important risk factor for reoperation after lumbar fusion surgery. Therefore, this MRI-based tool may be used to assist surgeons in preoperative planning for spine surgeries with the goal of reducing the risk of requiring reoperation.

Application of oblique lumbar interbody fusion for lumbar intervertebral pyogenic infection

Objective To investigate the safety, key techniques and clinical efficacy of OLIF (oblique lumbar interbody fusion) corridor combined with lumbar intervertebral debridement, fusion with two interbody and internal fixation for the treatment of single-level lumbar pyogenic spondylodiscitis. Methods From February 2016 to March 2017, data of 12 patients with single-level lumbar intervertebral pyogenic infection diagnosed in our hospital who had undergone oblique lumbar interbody fusion with two interbody and posterior pedicle screw fixation via Wiltse approach were retrospectively analyzed. Among them, there were 10 males and 2 females, aged from 49 to 79 years, with an average age of 65.4±9.5 years. The white blood cells (WBC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were recorded and analyzed before operation and at the last follow-up. Lumbar pain was assessed by visual analogue acale (VAS), Oswestry disability index (ODI), and clinical efficacy was assessed by the MOS 36-item short-form health survey (SF-36) and Kirkaldy-Willis criteria. The hospitalization time, operation time, intraoperative blood loss, pathological reports, etiological results and complications were recorded. Disc height (DH), segmental angle (SA) and Lumbar Lordosis (LL) were measured before operation and at the last follow-up. The fusion time was recorded. Paired t-test and ANOVA was used for data analysis. Results All patients underwent surgery successfully, including 6 cases using two titanium meshes and 6 cases using two autologous tricortical iliac bones. Pathogenic culture was positive in 10 cases, with a positive rate of 83.3%, including 4 cases of streptococcus, 4 cases of Staphylococcus aureus, 1 case of Escherichia coli, and 1 case of Klebsiella pneumoniae. All patients were followed up for 16.1±5.1 months. At the last follow-up, WBC ([6.25±2.02] ×109/L) was lower than that before operation ([4.89±1.28] ×109/L), CRP (preoperation 58.73±52.56 mg/L vs postoperation 8.48±8.79 mg/L) and ESR (preoperation 51.88±19.04 mm/1 h vs postoperation 9.25±5.50 mm/1 h) were significantly lower (P< 0.01). The VAS score was preoperation 6.67±1.63 and postoperation 1.50±0.55, ODI score was preoperation 72.57%±3.41% and postoperation 18.00%±2.31%, and both were significantly lower postoperatively (P < 0.01). SF-36 score (preoperation 56.33±4.93 vs postoperation 73.73±5.86) was significantly higher (P< 0.01) respectively. The postoperative height of intervertebral space ([11.68±2.64] mm) was significantly higher than that before operation ([5.18±1.58] mm). The disc height at the last follow-up was (11.22±2.25) mm, and the loss rate was 1.89% compared with that of the immediate postoperatively; The postoperative lumbar lordosis angle (32.89°±14.52°) was significantly increased compared with that of the preoperative (24.16°±13.49°), and maintained well at the last follow-up (32.27°± 14.21°); The postoperative segmental angle (10.8°±8.51°) was significantly increased compared with that of the preoperative (5.81°±7.44°), and maintained well at the last follow-up (9.94°±7.87°). The fusion time ranged from 6 to 16 months, with an average of 9.2±3.5 months. The clinical efficacy was excellent in 10 cases (83.3%) and good in 2 cases (16.7%). The excellent and good rate was 100%. One case of pulmonary infection and pulmonary embolism occurred 2 days after operation, and recovered after use of antibiotics and anticoagulation treatment in ICU; one case of intramuscular venous thrombosis was found 1 day after operation, and recovered after anticoagulation treatment; no loosening of internal fixation was found, and no complications related to OLIF corridor occurred. Conclusion The treatment of single-level lumbar intervertebral pyogenic infection with OLIF corridor combined with lumbar intervertebral debridement, fusion with two interbody and internal fixation has the advantages of less blood loss, shorter operation time, more direct clearance of intervertebral space and left paravertebral focus, no disturbance of intraspinal canal and posterior structure, higher positive rate of etiology detection, shorter bedrest time and better restore of disc height and lumbar lordosis after operation. What’s more, the fusion rate is high and the clinical efficacy is satisfactory. Key words: Lumbar vertebrae; Infection; Spinal fusion

Utility of Patient-Specific Rod Instrumentation in Deformity Correction: Single Institution Experience.

Introduction Patient-specific instrumentation is an emerging technology with the promise of a better fit to patient anatomy. With the advent of deformity correction planning software, prefabricated rods can mitigate the need to bend rods in the operating room. Prefabricated rods allow the surgeon to provide a deformity correction closely in line with the surgical plan. Methods A retrospective chart review was completed, and all patients with Medicrea UNiD rod were included. A minimum of 3 week follow up upright 36-inch lateral radiograph was necessary for analysis. Overall 21 patients had Medicrea UNiD rods placed; four were excluded (one for cervicothoracic fusion, three for incomplete follow up). Pelvic parameters were documented from the preoperative, surgical plan, and postoperative radiographs using Surgimap (Nemaris Inc, NY). The parameters for the rods were based on the surgical plan. Paired t-tests were used to compare the preoperative, surgical plan, and postoperative pelvic parameters. Results Average lumbar lordosis, pelvic tilt, sacral slope, and sagittal vertical axis in preoperative radiographs were 35.12°, 24.82°, 28.65°, and 65.65 mm, respectively. In postoperative imaging, lumbar lordosis, pelvic tilt, sacral slope, and sagittal vertical axis were 57.00°, 18.00°, 35.71°, and 21.59 mm, respectively. There was a statistically significant difference in pelvic tilt, sacral slope, lumbar lordosis, and sagittal vertical axis between the preoperative film and surgical plan (p < 0.001), whereas no statistically significant difference was found between the surgical plan and postoperative pelvic parameters (p > 0.05). Conclusions Cases in which prefabricated rods were utilized demonstrated improved spinopelvic alignment. Additionally, there was no statistical difference between the surgical plan and postoperative imaging in terms of pelvic parameters. Future studies are needed to investigate the possible benefits of prefabricated rods.

Proximal Junctional Kyphosis in Degenerative Sagittal Deformity After Under- and Overcorrection of Lumbar Lordosis: Does Overcorrection of Lumbar Lordosis Instigate PJK?

Retrospective study. To analyze proximal junctional kyphosis (PJK) occurrence and surgical outcomes according to degree of lumbar lordosis (LL) correction relative to pelvic incidence (PI). In addition, risk factors of PJK including LL and sagittal vertical axis (SVA) correction were investigated. PJK is a common complication after adult spinal deformity surgery, and many factors are known to be associated with PJK. However, the effect of degree of LL correction on PJK occurrence is not fully understood. Eighty-three degenerative sagittal imbalance patients treated with deformity correction and long instrumented fusion to the sacrum with a minimum follow-up of 2 years were studied. Patients were divided into three groups according to their postoperative LL angle relative to PI using the SRS-Schwab classification: Group A (undercorrection, PI-LL> 10°), Group B (ideal correction, -10°<PI-LL≤10°), and Group C (overcorrection, PI-LL≤-10°). Prevalence, classification, and period of PJK occurrence were compared, and radiographic and clinical outcomes were analyzed. In addition, risk factors for PJK were evaluated. Overall PJK prevalence was 36.1% (30/83), and ratio of optimal SVA at postoperative and last follow-up were significantly higher in Group C (P < 0.001, P < 0.001). Nevertheless, there was no significant difference in PJK prevalence among three groups (40% vs. 37.5% vs. 34.1%; P = 0.907). Group C had better clinical outcomes (last follow-up ODI, VAS of LBP) than Group A (10.0 vs. 18.4; P < 0.001 and 1.5 vs. 4.0; P < 0.001). The increases in LL or SVA correction degree were not associated with PJK occurrence (P = 0.304, P = 0.201). Overcorrection showed good surgical outcomes without increasing PJK prevalence. Degrees of LL and SVA correction do not act as risk factors for PJK. Therefore, in adult spinal deformity patients, LL correction greater than PI may be a good choice that can result in better clinical outcomes without increasing risk of PJK. 4.

Prediction of Pelvic Inclination in the Sitting Position after Corrective Surgery for Adult Spinal Deformity.

Introduction Hip dislocation rates in patients with combined total hip arthroplasty (THA) and spinal deformity fixation are significantly higher than those of THA alone. Nevertheless, there are no treatment recommendations for patients who undergo THA and require a spine deformity correction later. Methods Twenty-eight patients underwent spinal fixation surgery for adult spinal deformity. Sagittal spinopelvic alignment was analyzed on lateral radiographs taken preoperatively and postoperatively in the sitting and standing positions. Univariate linear regression analysis was conducted to identify the factors affecting the pelvic inclination in the sitting position after spinal fixation. Multiple regression analysis was conducted to determine the most efficient combination of radiographic parameters for predicting postoperative pelvic inclination while sitting. Results There were significantly weak associations between postoperative sacral slope (SS) in the sitting position and the following factors: the number of vertebral levels fused (β = 0.30, p = 0.003); the presence of sacral fixation (β = 0.22, p = 0.01); the presence of sacroiliac joint fixation (β = 0.24, p = 0.008); and preoperative SS while standing and sitting (β = 0.21, p = 0.01 and β = 0.34, p = 0.001). Postoperative lumbar lordosis (LL) while standing was strongly associated with postoperative SS in the sitting position (β = 0.67, p <.0001). The combination of postoperative LL in the standing position and preoperative SS in the sitting position was the best fit, and the adjusted R-squared was 0.82. Conclusions We devised a prediction formula for pelvic inclination while sitting after spinal fixation that has high predictability: postoperative SS while sitting = 11.7+ (0.4 × postoperative planned LL while standing) + (0.16 × preoperative SS while sitting). This study could be the basis for treatment recommendations for patients who have undergone THA and require a spine deformity correction later.

Clinical and Short-Term Radiographic Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion With Expandable Lordotic Devices.

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a well-accepted procedure for the treatment of degenerative lumbar disease. However, its ability to restore lumbar lordosis has been limited. Development of expandable lordotic interbody devices has challenged this limitation, furthering the scope of minimally invasive surgery. To evaluate the radiographic and clinical effects of expandable lordotic interbody devices placed through an MIS-TLIF approach. We conducted a retrospective review of 32 1-level and 18 2-level MIS-TLIFs performed using lordotic expandable interbody devices. Lumbar radiographic measurements, Oswestry Disability Index scores (ODI), and Visual Analogue Scale scores (VAS) were obtained at preoperative, 6 wk follow up, and last follow up time points. Last follow up occurred at a mean of 11.5±7.6 mo (mean±SD). At 6-wk follow-up, segmental lordosis, disc height, and foraminal height increased by an average of 3.4°, 6.4 mm, and 4.4 mm, respectively. Only the 2-level group showed a significant increase in lumbar lordosis of 5.8°. No significant changes occurred in sacral slope, pelvic tilt, or pelvic incidence. Average ODI and VAS decreased by -12.0 and -4.5, respectively. Postoperative lumbar lordosis inversely correlated with preoperative lordosis in patients with an initial Pelvic Incidence to Lumbar Lordosis mismatch (PI-LL) of >10°, (r=-0.5, P=.009). When applied across 2-levels, MIS-TLIF using expandable lordotic interbody devices produced a significant increase in lumbar lordosis. Preoperative lumbar lordosis was found to be a predictor of postoperative lumbar lordotic change in patients with sagittal imbalance.

Minimally invasive multilevel lateral lumbar interbody fusion with posterior column osteotomy compared with pedicle subtraction osteotomy for adult spinal deformity

BACKGROUND CONTEXTPedicle subtraction osteotomy (PSO) is highly effective as a sagittal correction approach in patients with adult spinal deformity, but relevant issues such as surgical complexity and long-term complications limit its applicability. Recently, minimally invasive techniques have been reported to be useful for surgical treatment of adult spinal deformity; however, few reports have directly compared these techniques with PSO. PURPOSEThe purpose of this study was to evaluate the radiological and clinical efficacies of oblique lateral interbody fusion (OLIF) with posterior column osteotomy (PCO) using stiff rods (6.35-mm cobalt chrome [CoCr]). STUDY DESIGNRetrospective comparative study. PATIENT SAMPLEOne-hundred six patients (average age 71.3 years) diagnosed with adult spinal deformity presenting with sagittal imbalance for whom follow-up of over 2 years after sagittal correction (between 2013 and 2017) was available. OUTCOME MEASURESDescription and analysis of X-ray, computed tomography scans, operative time, estimated blood loss, and clinical outcomes (Oswestry Disability Index [ODI] and Visual Analog Scale [VAS]). METHODSA comparative analysis was performed evaluating spinopelvic parameters and clinical outcomes including the ODI, VAS, and complications in patients who underwent PSO (PSO group; n=65) or multilevel prepsoas OLIF combined with PCO and open posterior spinal fusion using 6.35-mm CoCr rods (OLIF group; n=41). The authors have no conflicts of interest to disclose. RESULTSThere were no differences in preoperative spinopelvic parameters between the PSO and OLIF groups. Although no differences were observed between the two groups in terms of postoperative SVA (−12.66 mm vs. −16.44 mm), postoperative lumbar lordosis (−71.46° vs. −72.55°), lumbar lordosis correction (77.96° vs. 73.54°), or postoperative pelvic tilt (9.35° vs. 7.17°), the estimated blood loss was significantly lower in the OLIF group (2824 mL vs. 1736 mL, p<.05). No differences were observed in clinical outcomes (ODI, VAS, and clinical complications), proximal junctional kyphosis, and spinopelvic parameters between the two groups 2 years after surgery. However, pseudarthrosis during the follow-up period, including rod fracture, occurred less frequently in the OLIF group compared with that in the PSO group (p<.05). OLIF was performed from the T12–L1 to L5–S1 regions (124 segments), with an average of three segments per patient. The computed tomography scans immediately after surgery showed an average segmental correction of −18° and 12.9% (16 segments) of 124 segments showed a correction angle of >30°. CONCLUSIONSMultilevel OLIF with PCO using a stiff rod to treat severe sagittal imbalance resulted in similar levels of sagittal balance and lordosis correction as obtained by PSO. Multilevel OLIF with PCO using a stiff rod can be an effective alternative to PSO for patients with severe sagittal imbalance.

Sagittal Balance in Adolescent Idiopathic Scoliosis Managed With Intraoperative Skull Femoral Traction.

This is a retrospective cohort, single-center quality improvement study. To evaluate the effect of the intraoperative skull femoral traction (IOSFT) on sagittal balance in posterior spinal instrumentation (PSI) to manage scoliosis. IOSFT has been used routinely as an adjunct technique for facilitating PSI to manage scoliosis in our institution since 2010. Previous studies have raised concerns regarding the negative effect of IOSFT on lumbar lordosis. The medical records and radiographs of 113 patients with adolescent idiopathic scoliosis managed with single stage PSI were reviewed. Eighty-five patients were operated with IOSFT (traction group) and 28 patients were operated without traction (nontraction group). Patients who had double (anterior-posterior) approaches or nonidiopathic scoliosis were excluded. Sagittal balance and pelvic parameters at 2 years of postoperative follow-up were the primary outcome measures. Statistical analysis was done with R for statistical computing. Median values and interquartile range were compared between groups using Wilcoxon rank sum, Fischer exact, and Welch t tests. P-values of <0.05 were considered statistically significant. No significant differences were found comparing postoperative lumbar lordosis in the nontraction group (54 degrees) with the traction group (53 degrees) (P=0.4953). No significant differences were found in postoperative sagittal vertical axis medians comparing both groups, with 17 mm in the nontraction group and 18 mm in the traction group (P=0.3994). No significant differences were found in postoperative pelvic parameters. The median pelvic incidence was 52 degrees in the nontraction group and 50 degrees in the traction group (P=0.2711). According to our results, the use of IOSFT as an adjunct to facilitate PSI for managing adolescent idiopathic scoliosis had no measurable negative impact on sagittal balance in our IOSFT cohort.

Risk Factor Analysis of the Incidence of Subsequent Adjacent Vertebral Fracture After Lumbar Spinal Fusion Surgery with Instrumentation

This study aimed to evaluate the risk factors for adjacent vertebral compression fractures after lumbar spinal fusion with instrumentation. A total of 669 patients who received lumbar instrumented spinal fusion between January 2012 and December 2015 were divided into 2 groups according to whether the adjacent vertebral body was fractured. The covariates recorded were age, sex, bone mineral density, and the number of fixed segments. The anatomic variables were pelvic incidence angle (PI), preoperative lumbar lordosis angle (Pre-LL), postoperative lumbar lordosis angle (Post-LL), Pre-LL minus Post-LL (Loss of LL), postoperative pelvic tilt (Post-PT), postoperative sacral slope, Pre-PI-LL mismatch (Pre-PI minus Pre-LL), and Post-PI-LL mismatch (Post-PI minus Post-LL). A 1-way analysis of variance (ANOVA) was performed with the aforementioned parameters, and binary logistic regression analysis was used to determine the relative risk factors. The 669 patients were followed-up for a mean of 2.7 ± 1.1 years (range, 2-4 years). Twenty-seven patients demonstrated fractures in the adjacent vertebral body after surgery. Analysis by 1-way ANOVA demonstrated that age, PI, Pre-LL, Post-LL, Loss of LL, Post-PI-LL mismatch, Post-PT, and osteoporosis were potential risk factors (all parameters, P< 0.001). Furthermore, binary logistic regression analysis showed that a large Loss of LL, osteoporosis, and old age were also risk factors for adjacent vertebral compression fractures. A greater Loss of LL, osteoporosis, and advanced age may be risk factors for fractures in the adjacent vertebral body of the fixed segment after lumbar fusion fixation.