Preoperative Lumbar Lordosis Research Articles

Predictors of Deterioration in Sagittal Balance Following Long Fusion Arthrodesis to L5 in Patients with Adult Scoliosis.

BackgroundThe aim of this study was to identify the predictors of deterioration in sagittal balance in patients with adult scoliosis following long fusion arthrodesis to L5.Material/MethodsA retrospective clinical study included 63 patients with adult scoliosis who underwent long fusion arthrodesis to L5, between February 2005 and May 2015. Radiological imaging values included the angle of lumbar lordosis (LL), and the angle of pelvic incidence (PI). The patients were divided into two cohorts, according to the threshold of average loss of sagittal vertical axis (SVA): a cohort with stable sagittal balance (SSB) and a cohort with deteriorated sagittal balance (DSB). Multivariate logistic regression analysis and the receiver operating characteristic (ROC) curve were used to identify the predictors of clinical outcome.ResultsThere were significant differences between the SSB and DSB cohorts in age (p<0.001), preoperative SVA (p<0.001), last follow-up SVA (p<0.001), preoperative LL (p=0.001), last follow-up LL (p<0.001), subsequent L5–S1 disc degeneration (p<0.001) and PI (p=0.028). Patient age >61.5 years (OR=1.251, 95% CI, 1.055–1.484) (P=0.010), preoperative SVA >3.54 cm (OR=1.844, 95% CI, 1.249–2.732) (P=0.002) and preoperative LL <19.0 degrees (OR=0.922, 95% CI, 0.869–0.979) (P=0.008) were identified as predictors of deterioration in sagittal balance.ConclusionsDeterioration in sagittal balance following long fusion arthrodesis to L5 in patients with adult scoliosis was associated with subsequent L5–S1 disc degeneration and loss of LL, age >61.5 years, preoperative SVA >3.54 cm, and preoperative LL <19.0 degrees.

Georg Schmorl Prize of the German Spine Society (DWG) 2017: correction of spino-pelvic alignment with relordosing mono- and bisegmental TLIF spondylodesis.

A balanced ratio of the main parameters of lumbar lordosis (LL) and pelvic incidence (PI) has high clinical relevance. A postoperative mismatch of LL and PI has been described in the literature to be associated with an inferior clinical outcome and higher postoperative revision rates. The aim of this retrospective, radiological study is to evaluate the magnitude of relordosing in mono-/bisegmental TLIF spondylodesis affecting the spino-pelvic alignment and the main contributing factors. 164 patients (pat.) underwent monosegmental (n=115, G1) and bisegmental (n=49, G2) TLIF spondylodesis, respectively, for different indications in 2016 in our hospital. Pelvic incidence, lumbar lordosis (preop., postop., 3months postop.), implanted cage sizes, and the use of additional Smith-Petersen osteotomies were analysed retrospectively. Patients were divided into three groups depending on match of LL/PI (PI-LL<10° green, PI-LL=10-20° yellow, PI-LL>20° red). Furthermore, a differentiation was made between surgeons with more than or less than 10years of spinal surgery experience, respectively. 29.6% of pat. in G1 and 16.3% in G2 showed a highly pronounced preoperative spino-pelvic mismatch (red). A high grade of mismatch (yellow) between LL/PI was seen in 29.6% in G1 and in 38.8% in G2. The remaining patients already had a balanced ratio of LL/PI (green). Through relordosing TLIF the LL could be corrected significantly (p<0.05). Therefore, the number of patients with a balanced sagittal alignment (green) increased from 40.9% preop. to 70.4% postoperative in G1 and from 44.9 to 85.7% in G2 (p<0.05). The number of pat. with highly pronounced preoperative mismatch (red) could be lowered in G1 from 29.6 to 13.9% and in G2 from 16.3 to 2% postoperative (p<0.05). In G1, the preoperative LL could be corrected from 46.3° to 53.8° (yellow) and 35.7° to 45.8° (red), while in G2, a correction was possible from 43.4° to 51.5° (yellow) and 36.6° to 50.1° (red) (p<0.05). No significant difference of segmental/complete LL was found between radiologic measurement immediately postoperative and at the 3-month follow-up. In monosegmental fusion higher cages sizes lead to a better match of LL/PI (p<0.05). The specific cage lordosis (5° vs. 10°) had no influence on the extent of relordosing. Experienced surgeons had significant higher postoperative matches of LL/PI (p<0.05) and accomplished more osteotomies (p<0.05). This retrospective study demonstrates that significant relordosing and, therefore, correction of the spino-pelvic alignment are possible with mono-/bisegmental TLIF spondylodesis. Positive influence of higher cage sizes and surgeon's experience was shown. We conclude that the ratio of LL/PI should be taken into account preoperatively in lumbar fusion surgery when planning mono-/bisegmental TLIF spondylodesis to optimize spino-pelvic alignment. These slides can be retrieved under Electronic Supplementary Material.

Predictors for Postoperative Loss of Lumbar Lordosis After Long Fusions Arthrodesis in Patients with Adult Scoliosis.

BackgroundLoss of lumbar lordosis (LL) is closely related to clinical symptoms and operative complications, however, few studies have identified its predictors. The purpose of our study was to identify the predictors for loss of LL in patients with adult scoliosis and provided evidence for surgical decision-making.Material/MethodsThere were 69 patients with adult scoliosis who underwent long fusions arthrodesis from January 2006 to March 2015 included in this retrospectively study. The patients were divided into two cohorts according the average loss of LL: cohort LL (loss of LL below the average) and cohort GL (loss of LL above the average). Multivariate logistic regression analysis and the receiver operating characteristic curve were used to identify the predictors.ResultsThere were statistically significant differences between the two cohorts in preoperative LL (p=0.002), postoperative LL (p=0.036), last follow-up LL (p<0.001), postoperative loss LL (p<0.001), preoperative SVA (p=0.007), last follow-up SVA (p=0.018), and pelvic incidence (p=0.016). Preoperative LL <23.5 (OR=0.920, 95% CI=0.870–0.973, p=0.003) and preoperative sagittal vertical axis >4.28 (OR=1.199, 95% CI=1.007–1.429, p=0.041) had good accuracy to predict postoperative loss of LL.ConclusionsLoss of LL commonly occurred after long fusions arthrodesis in patients with adult scoliosis. Postoperative deteriorated sagittal balance was more frequently than deteriorated coronal balance. Preoperative LL <23.5 and preoperative SVA >4.28 were the predictors for postoperative greater loss of LL in patients after long fusions arthrodesis. More attention should be paid to how to maintain the LL in patients with preoperative predictors, especially if both the identified predictors are present.

Changes in Cervical Alignment after Multilevel Schwab Grade II Thoracolumbar Osteotomies for Adult Spinal Deformity.

A retrospective cohort. The aim of this study was to describe changes in cervical alignment (CA) and cervical deformity (CD) after multilevel Schwab Grade II Osteotomies for adult spinal deformity (ASD). Reciprocal cervical and global changes after ASD surgery have not been previously described in the setting of multilevel osteotomy. Patients with long-segment (> five levels) fusion and osteotomy for ASD were radiographically evaluated. Pre- and postoperative cervical parameters evaluated included cervical lordosis (CL), C2-C7 sagittal vertical axis (C2-C7 SVA), and the T1 slope (T1S) minus the CL (T1S-CL). CD was defined as C2-C7 SVA >4 cm, CL < 0°, or T1S-CL ≥15°. Eighty-five patients (mean age 64 ± 11.1) were identified. Preoperative lumbar lordosis (LL) was 28.7° ± 13.8°, thoracic kyphosis (TK) was 28.2° ± 17.0°, C7 plumbline (C7 SVA) was 7.54 ± 6.7 cm, pelvic tilt (PT) was 30.0° ± 8.96°, lumbopelvic mismatch was 32° ± 17.1°, and the T1 pelvic angle (TPA) was 26.8° ± 12.9°. The C7 SVA and TPA corrected to 3.90 cm (P < 0.0001) and 17.5°, respectively (P < 0.0001). CD increased from 41 (48%) to 47 (55%) patients. The mean CL changed from 16.5° to 11.9° (P < 0.013), C2 SVA from 10.1 to 6.37 cm (P < 0.0001), T1S-CL from 10.2° to 14.3° (P = 0.021), and TK from 28° to 39° (P < 0.0001). A correlation was observed between T1S and CL (ρ = 0.435, P < 0.0001) and C2-C7 SVA (ρ = 0.624, P < 0.0001). T1S was the only independent predictor of both the postoperative C2-C7 SVA and CL.In this study, the presence of any single preoperative CD criterion was noted to be a risk for persistent global deformity on postoperative radiograph [odds ratio (OR) = 2.5] and the development of PJK (OR = 2.1). The T1-CL < 15° may indicate an even greater risk for persistent global deformity (OR = 3.5). Thoracolumbar fusion with multilevel Schwab Grade II Osteotomies was associated with a decreased CL and reciprocal increases in TK and T1S-CL. 3.

Oblique retroperitoneal approach for lumbar interbody fusion from L1 to S1 in adult spinal deformity.

In recent years, with advancements in surgical techniques and instrumentation, the lateral lumbar interbody fusion is being used increasingly as an alternative procedure to anterior approach. In this study, we illustrated a oblique retroperitoneal approach for lumbar interbody fusion with one incision site and tilting of the operation table in adult spinal deformity and evaluate the radiographical findings and clinical outcomes of patients treated using this technique. This study included 32 patients scheduled to undergo anterior and posterior long-level fusions for lumbar degenerative kyphosis or degenerative lumbar scoliosis. Data collected included blood loss, operative time, incision size, and perioperative complications. Pre- and postoperative radiographic parameters and clinical outcome measures were assessed. Mean follow-up time was 26.1months. The mean blood losses were 107.4 and 102.4ml, and the mean operative times were 116, 97, and 82min for the patients within five levels (4 cases), four levels (18 cases), and three levels (10 cases). The mean incision sizes were 14.63, 13.82, and 12.5cm in the patients with five, four, and three levels. The mean pelvic incidence was 50.3°. The mean preoperative sagittal vertical axis (SVA) was +13.66cm, and the last follow-up SVA was +2.94cm. The preoperative lumbar lordosis (LL) was 5.79°, and the last follow-up LL was 46.54°. The mean correction angle was 41°. The mean Cobb angle decreased from a preoperative value of 21.55° to 9.6°at the last follow-up. An oblique retroperitoneal approach is very safe, allowing reproducible access from L1 to S1 for lumbar interbody fusion in adult spinal deformity.

Influence of Lumbar Lordosis on the Outcome of Decompression Surgery for Lumbar Canal Stenosis.

Although sagittal spinal balance plays an important role in spinal deformity surgery, its role in decompression surgery for lumbar canal stenosis is not well understood. To investigate the hypothesis that sagittal spinal balance also plays a role in decompression surgery for lumbar canal stenosis, a prospective cohort study analyzing the correlation between preoperative lumbar lordosis and outcome was performed. A cohort of 85 consecutive patients who underwent decompression for lumbar canal stenosis during the period 2007-2011 was analyzed. Standing lumbar x-rays and 36-item short form health survey questionnaires were obtained before and up to 2 years after surgery. Correlations between lumbar lordosis and 2 parameters of the 36-item short form health survey(average physical score and bodily pain score) were statistically analyzed using linear mixed effects models. There was a significant correlation between preoperative lumbar lordosis and the 2 outcome parameters at postoperative, 6-month, 1-year, and 2-year timepoints. A10° increase of lumbar lordosis was associated with a 5-point improvement in average physical scores. This correlation was not present in preoperative scores. This study showed that preoperative lumbar lordosis significantly influences the outcome of decompression surgery on lumbar canal stenosis.

Incidence and risk factors of posterior cage migration following decompression and instrumented fusion for degenerative lumbar disorders.

The aim of this study was to explore the incidence and risk factors for posterior cage migration (PCM) following decompression and instrumented fusion for degenerative lumbar disorders, and hope to provide references in decision making and surgical planning for spine surgeons.By retrieving the medical records from January 2011 to December 2015, 286 patients were retrospectively reviewed. According to the occurrence of PCM, patients were divided into 2 groups: PCM group and non-PCM (N-PCM). To investigate risk values for PCM, 3 categorized factors were analyzed statistically: patient characteristics: age, sex, body mass index, bone mineral density, duration of disease, diagnosis, comorbidity, smoke; surgical variables: surgery time, blood loss, surgical strategy, cage morphology, cage size, surgical segment, fusion number, source of bone graft, surgeon experience; radiographic parameters: preoperative lumbar lordosis, correction of lumbar lordosis, preoperative lumbar mobility, preoperative intervertebral height, change of intervertebral height, Modic changes, paraspinal muscle degeneration.PCM was detected in 18 of 286 patients (6.3%) at follow-up. There was no statistically significant difference between the 2 groups in patient characteristics, except diagnosis, as lumbar spondylolisthesis was more prevalent in PCM group than that in N-PCM group. There was no difference between the 2 groups in surgical variables, except cage size and surgeon experience, as size of cage was smaller in PCM group than that in N-PCM group, and the surgeons with less experience (less than 3 years) were more prevalent in PCM group than that in N-PCM group. There was no statistically significant difference between 2 groups in radiographic parameters. Logistic regression model revealed that less than 3 years of surgeons’ experience, small cage size, and lumbar spondylolisthesis were independently associated with PCM.For patients with lumbar spondylolisthesis, they should be fully informed about the risk of PCM before operation. While for spinal surgeons, large cage should be preferred, and careful manipulation should be adopted, especially for new learners with less than 3-year experience of fusion surgery.

Lumbar Spinal Surgery in Patients With Parkinson Disease: A Multicenter Retrospective Study.

A multicenter, retrospective study. To identify the factors that affect surgery-related complications and to clarify the surgical strategy for treating lumbar disorders in Parkinson disease (PD). Previous studies have reported a high complication rate for spinal surgery in patients with PD. Because of the limited number of studies, there are no guidelines for spinal surgery for PD patients. We retrospectively reviewed the records for 67 PD patients who underwent lumbar spinal surgery. The patients were divided into 3 groups: 12 patients underwent laminectomy (Laminectomy), 24 underwent fusion surgery (Fusion) for lumbar canal stenosis, and 31 underwent corrective surgery for spinal deformity (Deformity). We assessed surgery-related complications in each group. The Cox proportional hazards model was used to identify the factors that predicted surgical failure. The percentages of patients who experienced failure of the initial surgery were 33.3% in the Laminectomy group, 45.8% in the Fusion group, and 67.7% in the Deformity group. The rates of implant failure were high in the Fusion and Deformity groups (33.3% and 38.7%, respectively). The Deformity group had a high rate of postoperative fracture (41.9%). These complications occurred at the most caudal site within a year after surgery and resulted in progression of kyphotic deformity. Multivariate analysis revealed that preoperative lumbar lordosis angle (LL) (per -1 degree) was associated with a failure of the initial surgery (hazard ratio, 1.024; 95% confidence interval, 1.008-1.04; P=0.003). We have demonstrated that a small preoperative LL increases the risk for failure of the initial surgery. Attaining and maintaining the proper lumbar lordosis with rigid fixation may be necessary in PD patients with a small preoperative LL.

Incidence and risk factors of persistent low back pain following posterior decompression and instrumented fusion for lumbar disk herniation.

IntroductionThe aim of this study was to explore the incidence and risk factors of persistent low back pain (PLBP) following posterior decompression and instrumented fusion for lumbar disk herniation and to provide references in decision-making and surgical planning for both spinal surgeons and surgically treated patients.Patients and methodsBy retrieving the medical records from January 2013 to December 2016, 221 patients were retrospectively reviewed. Patients were classified as having PLBP if numeric rating scale (NRS) scores were >50 at all postoperative follow-up time points (3 months, 6 months, and 12 months). According to the occurrence of PLBP, patients were divided into two groups: PLBP group and non (N)-PLBP group. To investigate risk values for PLBP, the following three categorized factors were analyzed statistically. Patient characteristics: age, gender, body mass index (BMI), preoperative low back pain, comorbidity, smoking, and drinking. Surgical variables: surgical strategy, surgical segment, the number of fusion levels, surgery time, blood loss, and size of incision. Radiographic parameters: preoperative lumbar lordosis (LL), correction of LL at immediate postoperation, Modic changes, and preoperative paraspinal muscle degeneration.ResultsPLBP was detected in 16 patients and were enrolled into the PLBP group. There was no difference between the two groups in age, gender, BMI, comorbidity, smoking, and drinking. The preoperative low back pain was more severe in the PLBP group than that in the N-PLBP group. There was no difference in surgery time, blood loss, surgical strategy, number of fusion levels, and the size of incision. Surgery segment at L5–S1 was more prevalent in the PLBP group than that in the N-PLBP group, and there was no difference in preoperative LL, correction of LL, preoperative lumbar mobility, and Modic changes. The fatty infiltration rate (FIR) was larger in the PLBP group than that in the N-PLBP group. Multivariate logistic regression model revealed that preoperative low back pain (NRS > 35), surgery segment at L5–S1, and FIR > 15% were independently associated with PLBP.ConclusionThe incidence of PLBP following posterior decompression and instrumented fusion for lumbar disk herniation is 7.2%, and the risk factors include preoperative low back pain, surgery segment at L5–S1, and preoperative paraspinal muscle degeneration.

Incidence and risk factors of adjacent segment disease following posterior decompression and instrumented fusion for degenerative lumbar disorders.

The purpose of this study was to explore incidence and risk factors of adjacent segment disease (ASD) following posterior decompression and instrumented fusion for degenerative lumbar disorders, and hope to provide references in decision making and surgical planning for both spinal surgeon and surgically treated patients.By retrieving the medical records from January 2011 to December 2013 in our hospital, 237 patients were retrospectively reviewed. According to the occurrence of ASD at follow up, patients were divided into 2 groups: ASD and N-ASD group. To investigate risk values for the occurrence of ASD, 3 categorized factors were analyzed statistically: Patient characteristics: age, sex, body mass index (BMI), bone mineral density (BMD), duration. Surgical variables: surgical strategy, number of fusion level, surgery segment, surgery time, blood loss, intraoperative superior facet joint violation. Radiographic parameters: preoperative lumbar lordosis, preoperative angular motion at adjacent segment, preoperative adjacent segment disc degeneration, preoperative paraspinal muscle degeneration.Postoperative ASD was developed in 15 of 237 patients (6.3%) at final follow up. There was no statistically significant difference between the 2 groups in patient characteristics of age, sex composition, BMD, duration, while the BMI was higher in ASD group than that in N-ASD group. There was no difference in surgical variables of surgical strategy, number of fusion level, surgery segment, surgery time, blood loss, while intraoperative superior facet joint violation was more common in ASD group than that in N-ASD group. There was no difference in radiographic parameters of preoperative lumbar lordosis, preoperative paraspinal muscle degeneration, while preoperative adjacent segment disc degeneration were more severe in ASD group than that in N-ASD group. The Logistic regression analysis revealed that, BMI >25 kg/m2, preoperative disc degeneration, and superior facet joint violation were independently associated with ASD.In conclusion, higher BMI, preoperative disc degeneration at adjacent segment and intraoperative superior facet joint violation are risk factors for ASD. Patients who are overweight or obesity and with preoperative disc degeneration at adjacent segment should be fully informed the risk of ASD. For surgeons, it is essential to prevent superior facet joint violation in pedicle screw insertion procedure.

Correlation analysis between change in thoracic kyphosis and multilevel facetectomy and screw density in main thoracic adolescent idiopathic scoliosis surgery

Background ContextControversy exists regarding the effects of multilevel facetectomy and screw density on deformity correction, especially thoracic kyphosis (TK) restoration in adolescent idiopathic scoliosis (AIS) surgery. PurposeThis study aimed to evaluate the effects of multilevel facetectomy and screw density on sagittal plane correction in patients with main thoracic (MT) AIS curve. Study DesignA retrospective correlation and comparative analysis of prospectively collected, consecutive, non-randomized series of patients at a single institution was undertaken. Patient SampleSixty-four consecutive patients with Lenke type 1 AIS treated with posterior correction and fusion surgery using simultaneous double-rod rotation technique were included. Outcome MeasuresPatient demographics and preoperative and 2-year postoperative radiographic measurements were the outcome measures for this study. MethodsMultiple stepwise linear regression analysis was conducted between change in TK (T5–T12) and the following factors: age at surgery, Risser sign, number of facetectomy level, screw density, preoperative main thoracic curve, flexibility in main thoracic curve, coronal correction rate, preoperative TK, and preoperative lumbar lordosis. Patients were classified into two groups: TK<15° group defined by preoperative TK below the mean degree of TK for the entire cohort (<15°) and the TK≥15° group, defined by preoperative TK above the mean degree of kyphosis (≥15°). Independent sample t tests were used to compare demographic data as well as radiographic outcomes between the two groups. There were no study-specific biases related to conflicts of interest. ResultsThe average preoperative TK was 14.0°, which improved significantly to 23.1° (p<.0001) at the 2-year final follow-up. Greater change in TK was predicted by a low preoperative TK (p<.0001). The TK <15° group showed significant correlation between change in TK and number of facetectomy level (r=0.492, p=.002). Similarly, significant correlation was found between change in TK and screw density (r=0.333, p=.047). Conversely, in the TK ≥15° group, correlation was found neither between change in TK and number of facetectomy level (r=0.047, p=.812), nor with screw density (r=0.030, p=.880). Furthermore, in patients with preoperative TK<15°, change in TK was significantly correlated with screw density at the concave side (r=0.351, p=.036) but not at the convex side (r=0.144, p=.402). ConclusionsIn patients with hypokyphotic thoracic spine, significant positive correlation was found between change in TK and multilevel facetectomy or screw density at the concave side. This indicates that in patients with AIS who have thoracic hypokyphosis as part of their deformity, the abovementioned factors must be considered in preoperative planning to correct hypokyphosis.

Preoperative, Intraoperative, and Postoperative Standing Lordosis After Pedicle Subtraction Osteotomy: An Analysis of Radiographic Parameters and Surgical Strategy

Study DesignRetrospective consecutive case series. ObjectivesThe objective of this study was to investigate the relationship between intraoperative and postoperative lumbar spine measurements after pedicle subtraction osteotomy (PSO). We analyzed the amount of lordosis lost between the prone intraoperative image and the final upright standing film. The outcome of this analysis should be used in preoperative planning for osteotomy procedures. MethodsSixteen patients had pre-, intra- and postoperative measurements of lumbar lordosis. Pre- and postoperative measures of pelvic parameters were also determined. Comparisons were made between pre-, intra- and postoperative measures of pelvic parameters, with specific attention to lumbar lordosis correction and the loss of correction with transition to a standing position. ResultsThe average pelvic mismatch between preoperative lumbar lordosis and pelvic incidence was 37 degrees whereas the postoperative mismatch measured 3.2 degrees. All patients had a significant correction of their lumbar lordosis. The lumbar lordosis showed a highly significant loss of 12.5 degrees from the intraoperative prone position to the postoperative standing position, with the average lumbar lordosis intraoperatively (67 degrees) decreasing to a standing lumbar lordosis of 54 degrees (p < .000001). ConclusionsThis analysis should aid in preoperative planning for sagittal global alignment correction and can reduce the chance of over- or under-correction in patients having a PSO procedure. Given the narrow postoperative target that is associated with better outcomes for patients, the loss of lumbar lordosis from prone to standing position may be a crucial variable in this planning process.

Anterior Hyperlordotic Cages: Early Experience and Radiographic Results

Introduction The mainstay of correction for hypolordotic lumbar deformities has been posterior osteotomies, such as the Smith Petersen, or three column osteotomies (TCO). TCO's while very powerful, are associated with significant neurological complications, variable lordotic correction, pseudarthrosis and loss of correction. We hypothesize that the advent of Hyperlordotic Cages (HLC) (cages with 20 or 30° of built in lordosis) will allow significant restoration of lumbar lordosis, and good predictability of the correction from an anterior approach, thus obviating the need for TCO's. Material and Methods We conducted a retrospective review of a single surgeon series of consecutive adult patients, undergoing Anterior Lumbar Interbody Fusion (ALIF) with HLC for degenerative spinal conditions or sagittal imbalance over a 15-month period. Patients had either a standalone ALIF or ALIF followed by posterior instrumented fusion, depending on underlying pathology. The anterior approach involved a retroperitoneal pararectus approach with resection of the anterior longitudinal ligament. Electronic medical records were reviewed for evidence of perioperative complications. Digital lateral spine radiographs were also reviewed to assess for Segmental Lordosis (SL) and its stability over time. Classic deformity measurments were also recorded. Results 69 HLC's inserted into 41 patients met our inclusion criteria, with a mean follow up of 8 months. Average age of patients was 55 years (23–76), and 29 were female. We implanted twenty-seven 30° HLC's, and forty-two 20° HLC's. The mean pre op lumbar lordosis of our cohort was 39o, post operatively this increased to 59° ( p &lt; 0.01). In 21 levels without spondylolisthesis, the 30° HLC's produced a mean SL of 28° (26–34). In 45 levels without spondylolisthesis the 20° HLC produced a mean SLC of 19°(16–22) p &lt; 0.01. In 7 levels with greater than grade 1 spondylolisthesis, 30° HLCs achieved 19° of SL (14–21) ( p &lt; 0.01). The majority of HLC's were placed in lower lumbar spine, 34 at L5/S1, and 23 at L4/5. Six (9%) HLC's displayed loss of correction (defined as SL loss &gt; 2°). The mean loss of SL was 4.5°(3–10). Complications included two transient neurological deficits (4.4%), one L5 palsy, and one L4 hyperesthesia, both observed after posterior instrumentation, 2 retroperitoneal collections, one requiring incision and debridement, 2 lymphoceles, both requiring laparoscopic fenestrations, and one enterocutaneous fistula requiring intervention. Average blood loss was 240ml(50–900). Conclusion Anterior insertion of HLC's is a predictable and reproducible method to correct lordosis, and therefore sagittal balance in complex deformities. The amount of SL obtained with a 30° HLC is comparable to TCO's but the 20% total complication rate is significantly lower than the 58% reported for TCO's in the literature. The ability to implant hyperlordotic cages at lower lumbar levels than traditional L2 or L3 level TCO enables a more anatomic restoration of the lumbar lordosis. Direct lateral cages have failed to demonstrate recreation of lordosis, but anterior insertion does appear to efficiently correct lordosis. Our blood loss (250ml) also compares favorably with reported values for TCO's. The authors therefore advocate the use of HLC's for ALIF to recreate lumbar lordosis.

Factors associated with improvement in sagittal spinal alignment after microendoscopic laminotomy in patients with lumbar spinal canal stenosis.

OBJECTIVE Little is known about the relationship between sagittal spinal alignment in patients with lumbar spinal canal stenosis (LSS) and objective findings such as spinopelvic parameters, lumbar back muscle degeneration, and clinical data. The purpose of this study was to identify the preoperative clinical and radiological factors that predict improvement in sagittal spinal alignment after decompressive surgery in patients with LSS. METHODS The records of 61 patients with LSS who underwent microendoscopic laminotomy and had pre- and postoperative clinical data collected were retrospectively reviewed. Spinopelvic parameters, including sagittal vertical axis (SVA), lumbar lordosis (LL), sacral slope, pelvic tilt, and pelvic incidence (PI), were evaluated. On T2-weighted MRI, the cross-sectional area and the percentage of fat infiltration of the paravertebral muscles (PVMs) before surgery were calculated. For patients with preoperative SVA > 40 mm (n = 30), the correlation between SVA improvement and preoperative clinical and radiographic parameters was calculated. RESULTS SVA improvement correlated with preoperative LL (r = -0.39) and PI -LL (r = 0.54). Multiple regression analysis showed that preoperative PI -LL (beta = 0.62; p < 0.01) and symptom duration (beta = -0.40; p < 0.05) were independently associated with SVA improvement. The percentage of fat infiltration of the PVM at L4-5 was significantly greater in patients with preoperative SVA ≥ 40 mm than in those patients with SVA < 40 mm. CONCLUSIONS Preoperative PI -LL and symptom duration were independently associated with SVA improvement in LSS patients with forward-bending posture. PVM degeneration at the lower lumbar level was significantly greater among patients with preoperative SVA ≥ 40 mm than in patients with SVA < 40 mm.

Overcorrection of lumbar lordosis for adult spinal deformity with sagittal imbalance: comparison of radiographic outcomes between overcorrection and undercorrection.

To determine the correlation of the difference between postoperative lumbar lordosis (LL) and ideal LL with the sagittal vertical axis (SVA) at the final follow-up in patients with adult spinal deformity (ASD). Fifty-one patients with degenerative lumbar kyphosis (DLK) (mean age 66.5years) who underwent surgical correction with a minimum 2-year follow-up were evaluated. Based on the difference between postoperative LL and ideal LL using the Korean version of Legaye's formula, we divided the 51 patients into two groups: overcorrection (degree of postoperative LL>ideal LL) and undercorrection (degree of postoperative LL<ideal LL). Our clinical series of patients comprised 24 in the overcorrection and 27 in the undercorrection group. No significant differences were found in preoperative pelvic incidence (PI 52.6° vs. 57.3°), sacral slope (SS 23.3° vs. 18.3°), LL (-6.9° vs. -2.3°), thoracic kyphosis (TK 4.7° vs. 4.9°) and SVA (140 vs. 139mm) except pelvic tilt (PT 29.4° vs. 39.0°), between the two groups. All the patients in the overcorrection group and 16 in the undercorrection group achieved postoperative optimal sagittal balance based on SVA≤50mm. In addition, significant differences in PT (10.5° vs. 26.7°), SS (42.1° vs. 30.6°), LL (-64.3° vs. -37.1°), TK (22.6° vs. 15.8°), and SVA (-1 vs. 41mm) between the two groups were observed postoperatively. Furthermore, four patients (16.7%) in the overcorrection group and eight (50%) in the undercorrection group had sagittal decompensation at the final follow-up. Our results showed that the difference between postoperative LL and ideal LL had a significant correlation with postoperative and final follow-up SVA in our clinical series. Overcorrection of LL is an effective treatment modality to maintain optimal sagittal alignment in patients with DLK; this suggests that it should be considered in preoperative planning for patients with ASD with sagittal imbalance.

Preservation or Restoration of Segmental and Regional Spinal Lordosis Using Minimally Invasive Interbody Fusion Techniques in Degenerative Lumbar Conditions: A Literature Review.

A literature review. The purpose of this study was to review lumbar segmental and regional alignment changes following treatment with a variety of minimally invasive surgery (MIS) interbody fusion procedures for short-segment, degenerative conditions. An increasing number of lumbar fusions are being performed with minimally invasive exposures, despite a perception that minimally invasive lumbar interbody fusion procedures are unable to affect segmental and regional lordosis. Through a MEDLINE and Google Scholar search, a total of 23 articles were identified that reported alignment following minimally invasive lumbar fusion for degenerative (nondeformity) lumbar spinal conditions to examine aggregate changes in postoperative alignment. Of the 23 studies identified, 28 study cohorts were included in the analysis. Procedural cohorts included MIS ALIF (two), extreme lateral interbody fusion (XLIF) (16), and MIS posterior/transforaminal lumbar interbody fusion (P/TLIF) (11). Across 19 study cohorts and 720 patients, weighted average of lumbar lordosis preoperatively for all procedures was 43.5° (range 28.4°-52.5°) and increased 3.4° (9%) (range -2° to 7.4°) postoperatively (P < 0.001). Segmental lordosis increased, on average, by 4° from a weighted average of 8.3° preoperatively (range -0.8° to 15.8°) to 11.2° at postoperative time points (range -0.2° to 22.8°) (P < 0.001) in 1182 patient from 24 study cohorts. Simple linear regression revealed a significant relationship between preoperative lumbar lordosis and change in lumbar lordosis (r = 0.413; P = 0.003), wherein lower preoperative lumbar lordosis predicted a greater increase in postoperative lumbar lordosis. Significant gains in both weighted average lumbar lordosis and segmental lordosis were seen following MIS interbody fusion. None of the segmental lordosis cohorts and only two of the 19 lumbar lordosis cohorts showed decreases in lordosis postoperatively. These results suggest that MIS approaches are able to impact regional and local segmental alignment and that preoperative patient factors can impact the extent of correction gained (preserving vs. restoring alignment). 4.

Anterior corpectomy via the mini-open, extreme lateral, transpsoas approach combined with short-segment posterior fixation for single-level traumatic lumbar burst fractures: analysis of health-related quality of life outcomes and patient satisfaction.

The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures. Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up. Twelve patients (7 men, 5 women, average age 42 years, range 22-68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5-8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16-68 months), and average radiographic follow-up was 37 months (range 6-68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0-52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery. Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Comparison of Radiographic Postoperative Outcomes Between Males and Females With AIS.

The primary aim was to compare postoperative radiographic outcomes between sexes among adolescent idiopathic scoliosis (AIS) patients. A total of 162 AIS patients (42 males and 120 females) undergoing pedicle screw instrumentation and posterior fusion were included. Coronal and sagittal curves and flexibilities were measured and calculated. The postoperative correction rate (CR), fulcrum bending correction index (FBCI), and Cincinnati correction index were evaluated to compare the surgical benefits between sexes.Males were older (16.79 vs 14.79 years, respectively; P < 0.01) and had stiffer curves than females (lateral bending flexibility percentage: 47.77 vs 52.57, respectively, P = 0.21; traction flexibility percentage: 35.48 vs 36.98, respectively, P = 0.98; fulcrum bending flexibility percentage: 56.13 vs 66.57, respectively, P < 0.05). Males and females exhibited similar Lenke classification schemes (P = 0.72), but had different Risser signs (P < 0.01). Although males had greater postoperative curves (20.81° vs 16.83°, respectively; P = 0.009), no obvious differences in the CRs were noted between males and females (FBCI: 145.20% vs 108.37%, respectively; P = 0.92). Smaller preoperative lumbar lordosis was noted in males than in females (40.05° vs 45.72°, respectively; P = 0.03), yet no statistically significant differences in the preoperative and postoperative sagittal curves were observed between the sexes. In conclusion, considering the preoperative flexibilities, the 2 sexes achieved comparable surgical benefits without sacrificing the sagittal balance.

An Algorithm to Predict Success of Indirect Decompression Using the Extreme Lateral Lumbar Interbody Fusion Procedure.

Purpose: The purpose of this study is to define an algorithm that will predict the success of indirect decompression without the need for direct decompression in patients undergoing lateral lumbar interbody fusions.Methods and Materials: A prospective cohort study was undertaken for patients undergoing indirect decompression with lateral lumbar interbody fusion. Patients had to meet the following criteria prior to indirect fusion: lack of facet fusion on CT, absence of free disc fragment or compressive facet joint cyst on MRI, absence of frank osteoporosis, lack of congenital and/or severe spinal stenosis on MRI, and significant reduction (greater than 50%) in leg and back pain at rest. We then assessed which patients at follow-up required a second stage open decompression procedure because of continued back and/or leg pain. Results: Our series included 28 patients who underwent indirect decompression with extreme lateral lumbar interbody fusion. Of the 28 patients, one patient required a second stage open decompression at follow-up. The most common level operated on was the L4-L5 level. Twelve patients underwent more than a single level fusion. Average preoperative lumbar lordosis was 29 degrees and average postoperative lordosis was 45 degrees. The average patient age was 66.3 years and average follow-up was 1.21 years. Conclusions: Our algorithm can be used as an aid to assess which patients may benefit from indirect decompression alone, compared to indirect decompression combined with posterior decompression procedures.

One-stage posterior spinal shortening by L5 partial spondylectomy for spondyloptosis or L5–S1 high-grade spondylolisthesis management

A case series of seven consecutive patients with L5-S1 spondyloptosis (SPP) and Meyerding IV spondylolisthesis (HGSPL) treated consecutively by a new surgical technique with partial reduction and fixation after spinal shortening. To report clinical and radiological outcomes of a spinal shortening procedure by a single posterior approach in seven patients with HGSPL and SPP. The surgical treatment of L5-S1 SPP and HGSPL remains challenging, and numbers of surgical treatment options have been described with several principles. We reported a new surgical technique achieving partial reduction and fixation of L5-S1 SPP and HGSPL and highlighted its clinical and radiological outcomes. Seven patients with Meyerding Grade IV (2), and Grade V (5) were operated consecutively between 2004 and 2011 for HGSPL and SPP. Surgery time, blood loss and complications were collected for all patients. The slip angle or Dubousset lumbo-sacral Angle (Dub-LSA), L5 slip percentage (%slip), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK) and C7-tilt were measured pre and postoperatively. All patients underwent posterior one-stage decompression with sacral dome osteotomy, L5 vertebrectomy with L5-S1 discectomy, and partial reduction and instrumented fusion in a single posterior approach. The mean age and follow-up were, respectively, 20 years and 65 months. The mean preoperative %slip was 115 %, which improved to 63 % postoperatively. The mean preoperative Dub-LSA, PT, LL, TK, and C7-tilt were 37°, 31°, -74°, 30°, and 6°, respectively, which improved to 94°, 25°, -44°, 42° and -0.14° postoperatively. No implant failure or pseudarthrosis were reported at last follow-up. This novel and efficient one-stage shortening technique offers the possibility to manage lumbosacral kyphosis and spinal local malalignment in L5-S1 SPP.