Interpedicular height as a predictor of radicular pain in adult degenerative scoliosis

The Lumbosacral Fractional Curve in Adult Degenerative Scoliosis

Spine surgeons are often faced with a profoundly difficult challenge in surgically treating adult degenerative scoliosis. Deformity correction surgery is complicated by the difficulty in offering extensive surgical corrections to the elderly, complication-prone population it commonly affects. As spine surgeons attempt to offer minimally invasive solutions to this disease process, the need for fusion of the fractional curve at L4, L5, and S1 may be discounted. A treatment strategy to identify, address, and treat the fractional curve with either open or minimally invasive techniques can lead to improved patient outcomes and decrease revision rates in this complicated pathologic process.

Percutaneous Intervertebral-Vacuum Polymethylmethacrylate Injection for Foraminal Stenosis with Degenerative Lumbar Scoliosis

BACKGROUND

Percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) is a minimally invasive procedure for low back pain in elderly patients with degenerative lumbar scoliosis (DLS). Patients with DLS often have radiculopathy as a result of foraminal stenosis in addition to low back pain. The purpose of this study was to evaluate the clinical and radiologic results of PIPI for foraminal stenosis with radiculopathy in elderly patients with DLS.

METHODS

We included patients with de novo DLS aged 65 years or older who underwent PIPI. The presence of an intervertebral vacuum on computed tomography and bone marrow edema on magnetic resonance imaging was required for inclusion. The intersegmental radiologic parameters on plain radiographs and computed tomography and the extent of bone marrow edema on magnetic resonance imaging were measured. The clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI).

RESULTS

We enrolled 40 patients with DLS who underwent PIPI. There were 16 men and 24 women, and the mean age was 79.0 ± 6.3 years. The mean foraminal height and extent of bone marrow edema showed a significant increase and reduction, respectively, after PIPI (P < 0.05). VAS score for radiculopathy and ODI significantly improved after PIPI (P < 0.01). The minimum clinically important differences in VAS score for radiculopathy and ODI at the final follow-up were 73.9% and 63.6%, respectively.

CONCLUSIONS

PIPI is a minimally invasive procedure not only for low back pain but also for radiculopathy in elderly patients with DLS. It leads to intervertebral stabilization and indirect decompression of the foramen.

Decompression of Lumbar Central Spinal Canal Stenosis Following Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This was a retrospective clinical series.

OBJECTIVE

The objective of this study was to evaluate radiologic changes in central spinal canal dimensions following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with placement of a static or an expandable interbody device.

SUMMARY OF BACKGROUND DATA

MIS-TLIF is used to treat lumbar degenerative diseases and low-grade spondylolisthesis. MIS-TLIF enables direct and indirect decompression of lumbar spinal stenosis, with patients experiencing relief from radiculopathy and neurogenic claudication. However, the effects of MIS-TLIF on the central spinal canal are not well-characterized.

MATERIALS AND METHODS

We identified patients who underwent MIS-TLIF for degenerative lumbar spondylolisthesis and concurrent moderate to severe spinal stenosis. We selected patients who had both preoperative and postoperative magnetic resonance imaging (MRI) and upright lateral radiographs of the lumbar spine. Measurements on axial T2-weighted MRI scans include anteroposterior and transverse dimensions of the dural sac and osseous spinal canal. Measurements on radiographs include disk height, neural foraminal height, segmental lordosis, and spondylolisthesis. We made pairwise comparisons between each of the central canal dimensions and lumbar sagittal segmental radiologic outcome measures relative to their corresponding preoperative values. Correlation coefficients were used to quantify the association between changes in lumbar sagittal segmental parameters relative to changes in radiologic outcomes of central canal dimensions. Statistical analysis was performed for "all patients" and further stratified by interbody device subgroups (static and expandable).

RESULTS

Fifty-one patients (age 60.4 y, 68.6% female) who underwent MIS-TLIF at 55 levels (65.5% at L4-L5) were included in the analysis. Expandable interbody devices were used in 45/55 (81.8%) levels. Mean duration from surgery to postoperative MRI scan was 16.5 months (SD 11.9). MIS-TLIF was associated with significant improvements in dural sac dimensions (anteroposterior +0.31 cm, transverse +0.38 cm) and osseous spinal canal dimensions (anteroposterior +0.16 cm, transverse +0.32 cm). Sagittal lumbar segmental parameters of disk height (+0.56 cm), neural foraminal height (+0.35 cm), segmental lordosis (+4.26 degrees), and spondylolisthesis (-7.5%) were also improved following MIS-TLIF. We did not find meaningful associations between the changes in central canal dimensions relative to the corresponding changes in any of the sagittal lumbar segmental parameters. Stratified analysis by interbody device type (static and expandable) revealed similar within-group changes as in the overall cohort and minimal between-group differences.

CONCLUSIONS

MIS-TLIF is associated with radiologic decompression of neural foraminal and central spinal canal stenosis. The mechanism for neural foraminal and central canal decompression is likely driven by a combination of direct and indirect corrective techniques.

Disc degeneration spreads: long-term behavioural, histologic and radiologic consequences of a single-level disc injury in active and sedentary mice

STUDY DESIGN

A multi-cohort, case-control rodent study.

PURPOSE

Investigate the long-term behavioural, histologic and radiologic consequences on the complete lumbar spine of L4/5 intervertebral disc (IVD) injury in mice and determine if increased physical activity mitigates the observed changes.

METHODS

Cohorts of 2-month-old CD1 female mice underwent a single ventral puncture of the L4/5 IVD. 0.5-, 3- or 12-months after injury, general health (body weight and locomotor capacity), behavioural signs of axial discomfort (tail suspension, grip strength and FlexMaze assays) and radiating pain (von Frey and acetone tests) were assessed. Experimental groups with free access to an activity wheel in their home cages were including in the 12-month cohort. Lumbar disc status was determined using colorimetric staining and radiologic (X-ray and T2-MRI) analysis. Innervation was measured by immunoreactivity for PGP9.5 and calcitonin gene-related peptide.

RESULTS

No changes in general health or persistent signs of axial discomfort were observed up to one year post-injury. In contrast, signs of radiating pain developed in injured mice at 3 months post-injury, persisted up to 12 months and were reversed by long-term physical activity. At 12-months post-injury, degeneration was observed in non-injured lumbar discs. Secondary degenerating IVDs were similar to the injured discs by X-ray (narrowing) and T2-MRI (internal disc disruption) but did not show abnormal innervation. Increased physical activity had no impact on mechanically injured IVDs, but attenuated disc narrowing at other lumbar levels.

CONCLUSIONS

Mechanical injury of L4/5-IVDs induces delayed radiating pain and degeneration of adjacent discs; increased physical activity positively mitigated both.

Prospective investigation of Oswestry Disability Index and short form 36 subscale scores related to sagittal and coronal parameters in patients with degenerative lumbar scoliosis

PURPOSE

This study investigated relationships of Oswestry Disability Index (ODI) and Short Form 36 (SF-36) total and subscale scores with global spinal parameters in patients with degenerative lumbar scoliosis (DLS).

METHODS

This was a prospective single-center study of 126 consecutive patients with DLS. Disability was evaluated using the ODI and SF-36 total and subscale scores. Sagittal and coronal parameters were measured. Pearson's correlation analysis was performed to determine relationships between disability and radiographic parameters.

RESULTS

The study population included 76 women and 15 men (mean age, 70.2 ± 8.4 years). Mean Cobb angle was 18.9° ± 8.0°. The ODI total score and SF-36 physical component score were only correlated with coronal parameters. ODI pain intensity, personal care, lifting, sitting, and sex life domains were only correlated with coronal parameters. The walking, standing, social life, and traveling domain scores were correlated with coronal and sagittal parameters. The SF-36 bodily pain and vitality domain scores were only correlated with coronal parameters. The SF-36 physical function domain score was correlated with both coronal and sagittal parameters. Among the clinical and radiographic parameters, the personal care score and the coronal vertical-axis had the strongest correlation (r = 0.425), although the r² value was only 0.18.

CONCLUSIONS

ODI total score and most of the subscale scores were significantly, but weakly correlated with coronal parameters. Sagittal parameters were only correlated with some of the ODI and SF-36 subscale scores. Analysis using ODI and SF-36 subscale scores may aid in understanding and treatment of disability in patients with DLS.

Hounsfield Unit for Assessing Vertebral Bone Quality and Asymmetrical Vertebral Degeneration in Degenerative Lumbar Scoliosis

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

The aim of this study was to demonstrate the correlation between degenerative lumbar scoliosis (DLS) and osteoporosis based on Hounsfield unit (HU) measurement from computed tomography (CT) scans, and to investigate the asymmetrical vertebral degeneration in DLS.

SUMMARY OF BACKGROUND DATA

The correlation between DLS and osteoporosis measured by dual-energy x-ray absorptiometry (DEXA) is debated, since T-scores measured by DEXA scan can be overestimated due to abdominal vessel wall calcification, degenerative bony spurs, and facet hypertrophy. The reliability and accuracy of HU to determine osteoporosis are shown in many reports, but it has never been used to assess the vertebral bone quality for DLS patients.

METHODS

Nighty-five DLS patients were retrospectively reviewed. Regions of interest for HU were measured on three coronal images of the lumbar vertebrae. HU measurement of the whole vertebrae from L1 to L5 was obtained, then HU measurement within concave and convex sides were obtained separately in L5, upper and lower end vertebrae, apex vertebrae, neutral vertebrae, stable vertebrae.

RESULTS

HU value presented a gradually increasing trend from L1 to L5. No correlation was detected between Cobb angle and mean HU value of the 5 lumbar vertebrae, or between Cobb angle and HU value of every lumbar vertebrae separately. HU value was higher within concavity than that within convexity of the same vertebrae both in major and compensatory curve. Asymmetric HU ratio in apex vertebrae positively correlated with Cobb angle. Stable vertebrae were the first proximal vertebrae that present opposite orientation of asymmetric HU ratio from the other lumbar vertebrae.

CONCLUSION

Progression of degenerative scoliosis presents no correlation with osteoporosis based on HU measurement but could increase the asymmetrical vertebral degeneration, especially in apex vertebrae. Distraction of the pedicle screws at concave side, instead of compression of pedicle screws at convex side, should be a priority to correct lumbosacral curve.

LEVEL OF EVIDENCE

3.

Posterior column osteotomy plus unilateral cage strutting for correction of lumbosacral fractional curve in degenerative lumbar scoliosis

Background

Inadequate release of the posterior spinal bone elements may hinder the correction of the lumbosacral fractional curve in degenerative lumbar scoliosis, since the lumbosacral junction tends to be particularly rigid and may already be fused into an abnormal position. The purpose of this study was to evaluate the surgical outcome and complications of posterior column osteotomy plus unilateral cage strutting technique on lumbosacral concavity for correction of fractional curve in degenerative lumbar scoliosis patients.

Methods

Thirty-two degenerative lumbar scoliosis patients with lumbosacral fractional curve more than 15° that were surgically treated by posterior column osteotomy plus unilateral cage strutting technique were retrospectively reviewed. The patients’ medical records were reviewed to identify demographic and surgical data, including age, sex, body mass index, back pain, leg pain, Oswestry Disability Index, operation time, blood loss, and instrumentation levels. Radiological data including coronal balance distance, Cobb angle, lumbosacral coronal angle, sagittal vertical axis, lumbar lordosis, and lumbosacral lordotic angle were evaluated before and after surgery. Cage subsidence and bone fusion were evaluated at 2-year follow-up.

Results

All patients underwent the operation successfully; lumbosacral coronal angle changed from preoperative 20.1 ± 5.3° to postoperative 5.8 ± 5.7°, with mean correction of 14.3 ± 4.4°, and the correction was maintained at 2-year follow-up. Cobb’s angle and coronal balance distance decreased from preoperative to postoperative; the correction was maintained at 2-year follow-up. Sagittal vertical axis decreased, and lumbar lordosis increased from preoperative to postoperative; the correction was also maintained at 2-year follow-up. Lumbosacral lordotic angle presented no change from preoperative to postoperative and from postoperative to 2-year follow-up. Postoperatively, there were 8 patients with lumbosacral coronal angle more than 10°, they got the similar lumbosacral coronal angle correction, but presented larger preoperative Cobb and lumbosacral coronal angle than the other 24 patients. No cage subsidence was detected; all patients achieved intervertebral bone fusion and inter-transverse bone graft fusion at the lumbosacral region at 2-year follow-up.

Conclusion

Posterior column osteotomy plus unilateral cage strutting technique on the lumbosacral concavity facilitate effective correction of the fractional curve in degenerative lumbar scoliosis patients through complete release of dural sac as well as the asymmetrical intervertebral reconstruction by cage.

Transfacet Minimally Invasive Transforaminal Lumbar Interbody Fusion With an Expandable Interbody Device-Part II: Consecutive Case Series

BACKGROUND

Advances in operative techniques and instrumentation technology have evolved to maximize patient outcomes following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). The transfacet MIS-TLIF is a modified approach to the standard MIS-TLIF that leverages a bony working corridor to access the disc space for discectomy and interbody device placement.

OBJECTIVE

To evaluate clinical and radiographic results following transfacet MIS-TLIF using an expandable interbody device.

METHODS

We performed a retrospective review of consecutive patients who underwent transfacet MIS-TLIF for degenerative lumbar spondylolisthesis. Patient-reported outcome measures for pain and disability were assessed. Sagittal lumbar segmental parameters and regional lumbopelvic parameters were assessed on upright lateral radiographs obtained preoperatively and during follow-up.

RESULTS

A total of 68 patients (61.8% male) underwent transfacet MIS-TLIF at 74 levels. The mean age was 63.4 yr and the mean follow-up 15.2 mo. Patients experienced significant short- and long-term postoperative improvements on the numeric rating scale for low back pain (-2.3/10) and Oswestry Disability Index (-12.0/50). Transfacet MIS-TLIF was associated with an immediate and sustained reduction of spondylolisthesis, and an increase in index-level disc height (+0.71 cm), foraminal height (+0.28 cm), and segmental lordosis (+6.83°). Patients with preoperative hypolordosis (<40°) experienced significant increases in segmental (+9.10°) and overall lumbar lordosis (+8.65°). Pelvic parameters were not significantly changed, regardless of preoperative alignment. Device subsidence was observed in 6/74 (8.1%) levels, and fusion in 50/53 (94.3%) levels after 12 mo.

CONCLUSION

Transfacet MIS-TLIF was associated with clinical improvements and restoration of radiographic sagittal segmental parameters. Regional alignment correction was observed among patients with hypolordosis at baseline.

INFLUENCE OF THE MISDEF ALGORITHM ON THE THERAPEUTIC DECISION FOR VERTEBRAL DEFORMITY IN THE ADULT

ABSTRACT Objective The therapeutic decision in cases of adult spinal deformity takes numerous factors into account with a consequent variability in treatment options. The objective is to compare the impact of the MISDEF (minimally invasive spine deformity) algorithm on therapeutic decisions in cases of adult spinal deformity. Methods Prospective radiographic analysis of 40 cases of adult deformity. The cases were sent, in two steps, to 20 Latin American surgeons who had to choose among six treatment options with and without the use of the MISDEF. Results For the conducts of decompression, decompression and short fusion, decompression and fusion with interbody device, and osteotomy with extension of fusion to the thoracic spine, no significant differences were found when comparing decisions made with and without MISDEF. For osteotomy, we observed a tendency for the number of surgeons choosing this conduct to increase when the decision is made with MISDEF. We observed that the number of surgeons who decided on conservative treatment decreased with the use of MISDEF (p <0.001). In cases with sagittal vertical axis <6 cm or pelvic tilt <25 ° or PI-LL (pelvic incidence minus lumbar lordosis) <10 ° or coronal curve <20 °, there was a decrease in the conservative treatment option and an increase in osteotomy with proximal extension of the fusion with the use of MISDEF. Conclusions There is a tendency to increase indications of osteotomy and decrease the conservative treatment option when making a decision with MISDEF. The use of the algorithm showed no significant impact on the therapeutic decision in severe cases of adult deformity. Level of Evidence II; Prospective comparative radiographic analysis.

Efficacy of computed tomography in prediction of operability of L5/S1 foraminal stenosis using region of interest: A STROBE-compliant retrospective study

Symptoms of intervertebral foraminal stenosis are caused by compression of nerve root exiting the intervertebral foramen. Many attempts to measure the size of the neuromuscular exit have been made; however, only a few studies to compare the area differences between foramens by computed tomography (CT) were done. In this retrospective comparative study, we used the region of interest (ROI) in CT to measure and compare the area of intervertebral foramen between the healthy control group and the patient group.Eighty-one patients who underwent CT of the lumbar spine between May 2014 and December 2017 were enrolled. Using the medical imaging program, the foraminal area between L5 and S1 vertebrae was measured on the sagittal, coronal, and axial planes using ROI. Four groups were established for comparison: those diagnosed with foraminal stenosis by a radiologist and those who were not, those diagnosed with foraminal stenosis by orthopedic surgeons and those who were not. These groups were further divided into subcategories depending on whether the area was operated on for foraminal stenosis. Interobserver and intraobserver agreements were assessed.The mean age of patients was 56.5 years (range 17-84). The foraminal area of the surgical group on sagittal plane was significantly narrower than the control group (P = .005). However, the difference between the 2 groups on axial and coronal planes was not statistically significant (P > .1). Foraminal area <80 mm on sagittal images was a statistically significant risk factor for clinical symptom (P = .028) and that <65 mm was a statistically significant risk factor in predicting operability (P = .01). Interobserver and intraobserver agreements were fair to good on axial and coronal planes (about 0.7), whereas the agreements were excellent on sagittal plane (>0.9).In this study, we proved that measuring the intervertebral foraminal area using the ROI in CT in the lumbar spine is useful for diagnosing L5-S1 foraminal stenosis, especially on sagittal plane. Furthermore, not only does it provide aid in diagnosis, but it also helps predicting the operability of foraminal stenosis.

Correlation between multifidus muscle atrophy, spinopelvic parameters, and severity of deformity in patients with adult degenerative scoliosis: the parallelogram effect of LMA on the diagonal through the apical vertebra

BACKGROUND

There were several reports describing the biomechanics and microstructure of multifidus muscles in patients with lumbar disc herniation. However, correlations between lumbar multifidus muscle atrophy (LMA), spinopelvic parameters, and severity of adult degenerative scoliosis (ADS) have not been investigated. The study evaluated the impact of LMA and spinopelvic parameters on the severity of ADS.

METHODS

One hundred and thirty-two patients with ADS were retrospectively reviewed. Standing whole-spine X-ray was used to evaluate the coronal (coronal Cobb angle, CA; coronal vertical axis, CVA) and sagittal (sagittal vertical axis, SVA; thoracic kyphosis, TK; lumbar lordosis, LL; pelvic incidence, PI; pelvic tilt, PT; sacral slope, SS) parameters. LMA was evaluated on axial T2-weighted magnetic resonance imaging (MRI) at intervertebral levels above and below the vertebra at the apex of the scoliotic curve. Clinical symptoms were evaluated by the Oswestry Disability Index (ODI) and the Japanese Orthopaedic Association (JOA) score. Multiple linear regression was used to assess correlations between LMA, spinopelvic parameters, and severity of scoliosis.

RESULTS

LL and PT were negatively correlated with CA (P < 0.001); LL was positively correlated with SVA (P < 0.001). PI was positively correlated with CA (P < 0.001) and CVA (P < 0.001). PT (P < 0.001) and SS (P < 0.001) were negatively correlated with CVA. SS was negatively correlated with SVA (P < 0.001). Concave LMA at the upper or lower intervertebral level of the apical vertebra was positively correlated with CA (P ≤ 0.001); convex LMA at the upper or lower intervertebral level was negatively correlated with CA (P < 0.001). Convex LMA at the upper intervertebral level and concave LMA at the lower intervertebral level of the apical vertebra were negatively correlated with the SVA (P ≤ 0.001). At the upper intervertebral level, LMA on the concave side was positively correlated with CVA (P = 0.028); LMA on the convex side was negatively correlated with CVA (P = 0.012). PI was positively correlated with ODI (P < 0.001); PT (P < 0.001) and SS (P < 0.001) were negatively correlated with ODI. At the lower intervertebral level, LMA on the concave side was positively correlated with ODI (P = 0.038); LMA on the convex side was negatively correlated with ODI (P = 0.011). PI was positively correlated with JOA (P < 0.001); PT (P < 0.001) and SS (P < 0.001) were negatively correlated with JOA.

CONCLUSIONS

Spinopelvic parameters are correlated with the severity of ADS. Asymmetric LMA at both upper and lower intervertebral levels of the apical vertebra is positively correlated with CA. LMA on the diagonal through the apical vertebra is very important to maintain sagittal imbalance via parallelogram effect. LMA at lower intervertebral levels of the apical vertebra may have a predictive effect on ODI. JOA score seems to be more correlated with spinopelvic parameters than LMA.

The Influence of Diagnosis, Age, and Gender on Surgical Outcomes in Patients With Adult Spinal Deformity

STUDY DESIGN

Retrospective review of prospectively collected data from a multicentric database.

OBJECTIVES

To determine the clinical impact of diagnosis, age, and gender on treatment outcomes in surgically treated adult spinal deformity (ASD) patients.

METHODS

A total of 199 surgical patients with a minimum follow-up of 1 year were included and analyzed for baseline characteristics. Patients were separated into 2 groups based on improvement in health-related quality of life (HRQOL) parameters by minimum clinically important difference. Statistics were used to analyze the effect of diagnosis, age, and gender on outcome measurements followed by a multivariate binary logistic regression model for these results with statistical significance.

RESULTS

Age was found to affect SF-36 PCS (Short From-36 Physical Component Summary) score significantly, with an odds ratio of 1.017 (unit by unit) of improving SF-36 PCS score on multivariate analysis (P < .05). The breaking point in age for this effect was 37.5 years (AUC = 58.0, P = .05). A diagnosis of idiopathic deformity would increase the probability of improvement in Oswestry Disability Index (ODI) by a factor of 0.219 and in SF-36 PCS by 0.581 times (P < .05). Gender was found not to have a significant effect on any of the HRQOL scores.

CONCLUSIONS

Age, along with a diagnosis of degenerative deformity, may have positive effects on the likelihood of improvement in SF-36 PCS (for age) and ODI (for diagnosis) in surgically treated patients with ASD and the breaking point of this effect may be earlier than generally anticipated. Gender does not seem to affect results. These may be important in patient counseling for the anticipated outcomes of surgery.

Incidence and risk factors for multiple medical complications in adult degenerative scoliosis long-level fusion

Adult degenerative scoliosis (ADS) surgery is known for its high incidence of complications. The propose of this study was to determine current complication rates and the predictors of medical complications in surgical ASD patients. A retrospective study of 153 ADS patients who underwent long level spinal fusion with 2-year follow-up between 2012 and 2017. The patient- and surgical-related risk factors for each individual medical complication were identified by using univariate testing. All patients were divided into groups with and without medical complication, infection, neurological complications, and cardiopulmonary complications, respectively. Potential risk factors were identified using univariate testing. Multivariate Logistic regression was used to evaluate independent predictors of medical complications. The total medical complication incidence was 26.1%. Patient-related independent risk factors for the development of medical complications included diabetes, smoking; for infection were diabetes and smoking; for neurological complications were BMI and diabetes; for cardiopulmonary complications were hypertension, smoking and cardiac comorbidity. Surgical-related independent risk factors for the development of medical complications were fusion level, operative time, osteotomy, blood transfusion and LOS; for infection were fusion level, blood transfusion, and LOS; for neurological complication were fusion level, osteotomy and blood transfusion; for cardiopulmonary complication were fusion level. Diabetes and smoking were the most common patient-related independent risk factors increase the development of each individual medical complication. On the other hand, fusion levels and blood transfusion were the most common surgical-related independent risk factors increase the development of each individual medical complication. Prevention of these risk factors can reduce the incidence of complications in Chinese patients with ADS surgery.

Minimally invasive transforaminal lumbar interbody fusion with expandable versus static interbody devices: radiographic assessment of sagittal segmental and pelvic parameters

OBJECTIVE Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has been adopted as an alternative technique to hasten recovery and minimize postoperative morbidity. Advances in instrumentation technologies and operative techniques have evolved to maximize patient outcomes as well as radiographic results. The development of expandable interbody devices allows a surgeon to perform MIS-TLIF with minimal tissue disruption. However, sagittal segmental and pelvic radiographic outcomes after MIS-TLIF with expandable interbody devices are not well characterized. The object of this study is to evaluate the radiographic sagittal lumbar segmental and pelvic parameter outcomes of MIS-TLIF performed using an expandable interbody device. METHODS A retrospective review of MIS-TLIFs performed between 2014 and 2016 at a high-volume center was performed. Radiographic measurements were performed on lateral radiographs before and after MIS-TLIF with static or expandable interbody devices. Radiographic measurements included disc height, foraminal height, fused disc angle, lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt. Mismatch between pelvic incidence and lumbar lordosis were calculated for each radiograph. RESULTS A total of 48 MIS-TLIFs were performed, predominantly at the L4-5 level, in 44 patients. MIS-TLIF with an expandable interbody device led to a greater and more sustained increase in disc height when compared with static interbody devices. Foraminal height increased after MIS-TLIF with expandable but not with static interbody devices. MIS-TLIF with expandable interbody devices increased index-level segmental lordosis more than with static interbody devices. The increase in segmental lordosis was sustained in the patients with expandable interbody devices but not in patients with static interbody devices. For patients with a collapsed disc space, MIS-TLIF with an expandable interbody device provided superior and longer-lasting increases in disc height, foraminal height, and index-level segmental lordosis than in comparison with patients with static interbody devices. Using an expandable interbody device improved the Oswestry Disability Index scores more than using a static interbody device, and both disc height and segmental lordosis were correlated with improved clinical outcome. Lumbar MIS-TLIF with expandable or static interbody devices had no effect on overall lumbar lordosis, pelvic parameters, or pelvic incidence-lumbar lordosis mismatch. CONCLUSIONS Performing MIS-TLIF with an expandable interbody device led to a greater and longer-lasting restoration of disc height, foraminal height, and index-level segmental lordosis than MIS-TLIF with a static interbody device, especially for patients with a collapsed disc space. However, neither technique had any effect on radiographic pelvic parameters.

Risk factors for medical complications after long-level internal fixation in the treatment of adult degenerative scoliosis

PURPOSE

This study evaluates baseline patient characteristics and surgical parameters for risk factors of medical complications in ASD patients received posterior long level internal fixation.

METHODS

Analysis of consecutive patients who underwent posterior long-level instruction fixation for adult degenerative scoliosis (ADS) with a minimum of two year follow-up was performed. Pre-operative risk factors, intraoperative variables, peri-operative radiographic parameters, and surgical-related risk factors were collected to analyze the effect of risk factors on medical complications. Patients were separated into groups with and without medical complication. Then, complication group was further classified as major or minor medical complications. Potential risk factors were identified by univariate testing. Multivariate logistic regression was used to evaluate independent predictors of medical complications.

RESULTS

One hundred and thirty-one ADS patients who underwent posterior long segment pedicle screws fixation were included. Total medical complication incidence was 25.2%, which included infection (12.2%), neurological (11.5%), cardiopulmonary (7.6%), gastrointestinal (6.1%), and renal (1.5%) complications. Overall, 7.6% of patients developed major medical complications, and 17.6% of patients developed minor medical complications. The radiographic parameters of pre-operative and last follow-up had no significant difference between the groups of medical complications and the major or minor medical complications subgroups. However, the incidence of cerebrospinal fluid leak (CFL) in patients who without medical complications was much lower than that with medical complications (18.4 vs. 42.4%, P = 0.005). Independent risk factors for development of medical complications included smoking (OR = 6.45, P = 0.012), heart disease (OR = 10.07, P = 0.012), fusion level (OR = 2.12, P = 0.001), and length of hospital stay (LOS) (OR = 2.11, P = 0.000). Independent risk factors for development of major medical complications were diabetes (OR 6.81, P = 0.047) and heart disease (OR = 5.99, P = 0.049). Except for the last follow-up, Oswestry Disability Index and visual analog scale of the patient experienced medical complications trend higher score; the clinical outcomes have no significant difference between the medical and major complications groups.

CONCLUSION

Heart disease comorbidity is an independent risk factor for both medical and major medical complications. Smoking, fusion level, and LOS are independent risk factors for medical complication. Diabetes is the independent risk factors for major medical complications.