Long-term 2- to 5-year clinical and functional outcomes of minimally invasive surgery for adult scoliosis

A systematic review of pseudarthrosis and reoperation rates in minimally invasive adult spinal deformity correction

Background/objective

The recent development of minimally invasive surgical techniques (MIS) has made possible the correction of adult spinal deformity (ASD) with less blood loss and shorter hospital stays. However, minimally invasive placement of pedicle screws at the proximal level of the construct can increase pseudarthrosis risk, leading to implant failure, kyphosis, and reoperations. We aggregate existing literature to describe pseudarthrosis rates at the proximal thoracic or thoracolumbar junction in MIS and subsequent reoperation rates.

Methods

After a three-tied search strategy in PubMed, we identified 9 articles for study inclusion, describing outcomes from MIS correction of ASD, pseudarthrosis as complication, and surgery on 4+ levels. Baseline patient characteristics and combined rates of pseudarthrosis and reoperation were calculated.

Results

A total of 482 patients were studied with an average [range] age of 65.5 [60.4,72], 6.3 [4.4,11] levels fused per patient, follow-up time of 28.3 [12,39] months, and 64.8% females. Pseudarthrosis was reported in 28 of 482 pooled patients (5.8%) of which 15 of 374 pooled patients (4.0%) ultimately underwent a reoperation for pseudarthrosis. Post-operative characteristics included an estimated blood loss (EBL) of 527.1 [241,1466] mL, operating time of 297.9 [183,475] minutes, and length of stay of 7.7 [5,10] days. Among the papers comparing MIS to open surgery, all reported a significantly lower EBL in patients treated with MIS.

Conclusion

This analysis demonstrate a measurable pseudarthrosis risk when using MIS to treat ASD, overwhelming requiring reoperation. The benefits of MIS must be considered against the drawbacks of pseudarthrosis when determining ASD management.

Bibliometric Analysis of the Development, Current Status, and Trends in Adult Degenerative Scoliosis Research: A Systematic Review from 1998 to 2023

Purpose

Adult degenerative scoliosis (ADS) research lacks bibliometric analysis, despite numerous studies. This study aimed to systematically analyze the development, current status, hot topics, frontier areas, and trends in ADS research.

Patients and Methods

A systematic literature review was conducted in the Web of Science Core Collection database from January 1998 to June 2023. Information regarding the country, institution, author, journal, and keywords was collected for each article. Bibliometric analysis was performed using VOSviewer and Citespace software.

Results

The final analysis covered 1695 publications, demonstrating a steady increase in ADS research. The United States was the most prolific and influential country with 684 publications, followed by China and Japan. The University of California System was the most productive institution with 113 publications. Shaffrey, CI (47 publications) and Lenke, LG (41 publications) were top authors. The analysis revealed seven main research clusters: "intervertebral disc", "adult spinal deformity", "lumbar fusion", "minimally invasive surgery", "navigation", "postoperative complications", and "mental retardation". Keywords with strong bursts of activity included degeneration, prevalence, imbalance, classification, lumbar spinal stenosis, and kyphosis.

Conclusion

In conclusion, in recent years, ADS research has undergone rapid development. This study analyzed its hot topics, advancements, and research directions, making it the latest bibliometric analysis in this field. The findings aim to provide a new perspective and guidance for clinical practitioners and researchers.

Biomechanical Comparison of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases after Primary Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis

BACKGROUND AND OBJECTIVE

Adjacent segment disease (ASD) is a well-known complication after interbody fusion. Revision surgery is necessary for symptomatic ASD to further decompress and fix the affected segment. However, no optimal construct is accepted as a standard in treating ASD. The purpose of this study was to compare the biomechanical effects of different surgical approaches for the treatment of ASD after primary transforaminal lumbar interbody fusion (TLIF).

METHODS

A finite element model of the L1-S1 was conducted based on computed tomography scan images. The primary surgery model was developed with a single-level TLIF at L4-L5 segment. The revision surgical models were developed with anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), or TLIF at L3-L4 segment. The range of motion (ROM), intradiscal pressure (IDP), and the stress in cages were compared to investigate the biomechanical influences of different surgical approaches.

RESULTS

The results indicated that all the three surgical approaches can stabilize the spinal segment by reducing the ROM at revision level. The ROM and IDP at adjacent segments of revision model of TLIF was greater than those of other revision models. While revision surgery with ALIF and LLIF had similar effects on the ROM and IDP of adjacent segments. Compared among all the surgical models, cage stress in revision model of TLIF was the maximum in extension and axial rotation.

CONCLUSION

The IDP at adjacent segments and stress in cages of revision model of TLIF was greater than those of ALIF and LLIF. This may be that direct extension of the surgical segment in the same direction results in stress concentration.

Comparison of staged lateral lumbar interbody fusion combined two-stage posterior screw fixation and two osteotomy strategies for adult degeneration scoliosis: a retrospective comparative study

AIMS

The commonly used treatments of adult degeneration scoliosis (ADS) were posterior long segment screw fixation with osteotomies. Recently, lateral lumbar intervertebral fusion combined two-stage posterior screw fixation (LLIF + PSF) as a new strategy without osteotomy. Herein, this study aimed to compare the clinical and radiological outcomes among LLIF + PSF and pedicle subtraction osteotomy (PSO), posterior column osteotomies (PCO).

METHODS

Totals of 139 ADS patients underwent operation with 2 years longer follow-up visit between January 2013 and January 2018 in Ningbo No.6 Hospital were enrolled into this study. 58 patients were included in PSO group, 45 in PCO group and 36 in LLIF + PSF group, The clinical and radiological data were reviewed from medical records. Baseline characteristic, perioperative radiological data (sagittal vertical axis (SVA), coronal balance (CB), Cobb angle of Mian curve (MC), Lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence-lumbar lordosis mismatch (PI-LL)), clinical outcomes (VAS of back and leg, Oswestry disability index (ODI) and Scoliosis Research Society 22-question Questionnaire (SRS-22)) and complications were evaluated and compared.

RESULT

There were no significantly difference in baseline characteristics, preoperative radiological parameters and clinical outcomes among three groups. LLIF + PSF group was significantly shorter in operation time than other two groups (P < 0.05), whereas significant longer hospital stay was observed in LLIF + PSF group (P < 0.05). As for radiological parameters, LLIF + PSF group had significantly improvement in SVA, CB, MC, LL and PI-LL (P < 0.05). Moreover, LLIF + PSF group achieved significantly less correction loss in SVA, CB and PT than PSO and PCO group (1.5 ± 0.7 VS 2.0 ± 0.9 VS 2.2 ± 0.8, P < 0.05; 1.0 ± 0.4 VS 1.3 ± 0.5 VS 1.1 ± 0.7, P < 0.05 and 4.2 ± 2.8 VS 7.2 ± 3.1 VS 6.0 ± 2.8, P < 0.05). Significantly recovery in VAS of back and leg, ODI score and SRS-22 were found among all groups, however, LLIF + PSF shown significant better clinical therapy maintain at follow-up visit than other two groups (P < 0.05). There were no significantly difference in complications among groups (P = 0.66).

CONCLUSION

Lateral lumbar interbody fusion combined two-stage posterior screw fixation (LLIF + PSF) can achieve comparable clinical therapy for adult degeneration scoliosis as osteotomy strategies. However, furthermore more studies need be taken for verifying the effect of LLIF + PSF in the future.

Spinal Deformity Complexity Checklist for Minimally Invasive Surgery: Expert Consensus from the Minimally Invasive International Spine Study Group

BACKGROUND

We developed a spinal deformity complexity checklist (SDCC) to assess the difficulty in performing a circumferential minimally invasive surgery (MIS) for adult spinal deformity.

METHODS

A modified Delphi method of panel experts was used to construct an SDCC checklist of radiographic and patient-related characteristics that could affect the complexity of surgery via MIS approaches. Ten surgeons with expertise in MIS deformity surgery were queried to develop and refine the SDCC with 3 radiographic categories (x-ray, magnetic resonance imaging, computed tomography) and 1 patient-related category. Within each category, characteristics affecting MIS complexity were identified by initial roundtable discussion. Second-round discussion determined which characteristics substantially impacted complexity the most.

RESULTS

Thirteen characteristics within the x-ray category were determined. Spinopelvic characteristics, endpoints of instrumentation, and prior hardware/fusion were associated with increased complexity. Vertebral body rotation-as reflected by the Nash-Moe grade-added significant complexity. Psoas anatomy and spinal stenosis added the most complexity for the 5 magnetic resonance imaging characteristics. There were 3 characteristics in the CT category with pre-exisiting fusion, being the variable most highly selected. Of the 5 patient-related characteristics, osteoporosis and BMI were found to most affect complexity.

CONCLUSIONS

The SDCC is a comprehensive list of pertinent radiographic and patient-related characteristics affecting complexity level for MIS deformity surgery. The value of the SDCC is that it allows rapid assessment of key factors when determining whether MIS surgery can be performed effectively and safely. Patients with scores of 4 in any characteristic should be considered challenging to treat with MIS; open surgery may be a better alternative.

Intraoperative Navigation and Robotics in Pediatric Spinal Deformity

Current technologies for image guidance navigation and robotic assistance with spinal surgery are improving rapidly with several systems commercially available. Newer machine vision technology has several potential advantages. Limited studies have shown similar outcomes to traditional navigation platforms with decreased intraoperative radiation and time required for registration. However, there are no active robotic arms that can be coupled with machine vision navigation. Further research is necessary to justify the cost, potential increased operative time, and workflow issues but the use of navigation and robotics will only continue to expand given the growing body of evidence supporting their use.

Paraspinal muscle approach for neuromuscular scoliosis: A comparative study evaluating deformity correction and perioperative morbidity in 91 patients with minimum 2-year follow-up

PURPOSE

We present the paraspinal approach use for neuromuscular scoliosis with focus on deformity correction, perioperative (≤30 days) morbidity and outcome at a minimal follow-up length of 2 years.

METHODS

We prospectively collected data of 61 neuromuscular scoliosis patients operated using a paraspinal (Wiltse) approach between 2013 and 2019. We additionally collected data of 104 control cases, operated using a midline approach between 2005 and 2016. Fifteen Wiltse, respectively 37 control patients were excluded due to a short follow-up (<2 years), and 22 controls were excluded secondary to lacking follow-up data. Hence, 46 Wiltse and 45 control patients were compared.

RESULTS

Wiltse and control patients had comparable follow-up lengths, demographics, deformity corrections, complication rates, number of levels fused, and intensive care unit and hospital lengths of stay. Wiltse cases had a lower estimated blood loss (535 vs 1187 mL; p-value < 0.001), allogenic transfusion rate (48% vs 96%; p-value < 0.001), and operating time (ORT) (337 vs 428 min; p-value < 0.001) than controls. This was also the case when selecting for patients without pelvic fixation (p-values < 0.001). When selecting the cases with pelvic fixation (20 among 91 cases), only the number of levels fused and the ORT differed significantly according to the approach (p-value <0.015 and <0.041).

CONCLUSION

The paraspinal approach for neuromuscular scoliosis is safe, associated with significant deformity correction, reduced estimated blood loss, and allogenic transfusion rate. These potential benefits still need to be evaluated, especially for cases with pelvic fixation, with further follow-up of larger cohorts.

LEVEL OF EVIDENCE

level III.

The clinical effectiveness and complications of lumbar selective fenestration and concave-side fusion (LSFCF) in degenerative lumbar scoliosis (DLS) combined with lumbar spinal stenosis (LSS)

PURPOSE

This retrospective study was performed to analyze the clinical effects and complications of LSFCF in the surgical treatment of DLS combined with lumbar spinal stenosis (LSS).

METHODS

A total of 26 eligible patients (mean age, 64.73 y; 17 men, 9 women) with DLS combined with LSS were included and LSFCF surgery was performed. An independent spine surgeon retrospectively reviewed the medical records and radiographs of all patients to evaluate surgical data and surgery-related complications. Preoperative, postoperative, and follow-up questionnaires were obtained to assess clinical outcomes.

RESULTS

The average follow-up period of this study was 20.14 ± 5.21 months. The operation time and blood loss of patients underwent LSFCF were 129.33 ± 15.74 min and 356.13 ± 21.28 ml. The clinical effects of all patients in terms of visual analogue scale (VAS) and Oswestry disability index (ODI) have been significantly improved at the final follow-up postoperatively (P < 0.05). Complications such as infection, cerebrospinal fluid leakage, nerve injury, and internal fixation failure, etc. were not observed during the follow-up period.

CONCLUSION

The LSFCF surgery is a safe and effective treatment for DLS patients combined with LSS.

Management of severe adult spinal deformity with circumferential minimally invasive surgical strategies without posterior column osteotomies: a 13-year experience

OBJECTIVE

To evaluate the mid- to long-term clinical outcomes of circumferential minimally invasive surgery (CMIS) without posterior column osteotomies for severe adult spine deformity (ASD) correction.

METHODS

All patients with a minimum of 2-year follow-up undergoing staged CMIS correction of ASD from January 2007 to July 2018 were identified. All included patients had fusion of 3 or more interbody levels that spanned the L5-S1 junction. Only patients with severe deformity, Coronal Cobb > 50° or at least one SRS-Schwab ++ sagittal modifier (SVA > 95 mm, or PI-LL > 20, or PT > 30) were included. All complications were noted.

RESULT

136 patients met inclusion criteria; mean age of patients was 63.6 years (21-85, SD 13.7). The mean follow-up was 82.8 months (24-159, SD 36.6). The mean number of levels fused was 7 (3-16, SD 3). A total of 40 (29.4%) major complications were noted at final follow-ups: 2 (1.4%) intra-operative, 12 (8.9%) peri-operative (≤ 6 weeks from index), 26 (19.1%) post-operative (> 6 weeks from index). There was a total of 53 (40.0%) minor complications. Seven (5.1%) patients who developed radiographic proximal junctional kyphosis. Three patients (2.2%) developed proximal junctional failure. There were 8 (5.9%) cases of pseudarthrosis. Five of these occurred in patients undergoing AxiaLIF. All patients experienced improvements in patient-perceived outcomes (VAS, TIS, ODI, and SRS-22) and radiographic parameters at last follow-up when compared to pre-op (p < 0.05).

CONCLUSION

Rates of complications with CMIS correction of severe ASD are lower than published rates of complications seen with open ASD correction. Specifically, the incidence of catastrophic complications is lower. Furthermore, CMIS is associated with significant improvements in clinical and functional outcomes, low rates of pseudarthrosis and proximal junctional kyphosis. Therefore, in the appropriately selected patient, CMIS may be an excellent alternative approach to addressing severe ASD.

Biomechanical study of oblique lumbar interbody fusion (OLIF) augmented with different types of instrumentation: a finite element analysis

Background

To explore the biomechanical differences in oblique lumbar interbody fusion (OLIF) augmented by different types of instrumentation.

Methods

A three-dimensional nonlinear finite element (FE) model of an intact L3-S1 lumbar spine was built and validated. The intact model was modified to develop five OLIF surgery models (Stand-alone OLIF; OLIF with lateral plate fixation [OLIF + LPF]; OLIF with unilateral pedicle screws fixation [OLIF + UPSF]; OLIF with bilateral pedicle screws fixation [OLIF + BPSF]; OLIF with translaminar facet joint fixation + unilateral pedicle screws fixation [OLIF + TFJF + UPSF]) in which the surgical segment was L4–L5. Under a follower load of 500 N, a 7.5-Nm moment was applied to all lumbar spine models to calculate the range of motion (ROM), equivalent stress peak of fixation instruments (ESPFI), equivalent stress peak of cage (ESPC), equivalent stress peak of cortical endplate (ESPCE), and equivalent stress average value of cancellous bone (ESAVCB).

Results

Compared with the intact model, the ROM of the L4–L5 segment in each OLIF surgery model decreased by > 80%. The ROM values of adjacent segments were not significantly different. The ESPFI, ESPC, and ESPCE values of the OLIF + BPSF model were smaller than those of the other OLIF surgery models. The ESAVCB value of the normal lumbar model was less than the ESAVCB values of all OLIF surgical models. In most postures, the ESPFI, ESPCE, and ESAVCB values of the OLIF + LPF model were the largest. The ESPC was higher in the Stand-alone OLIF model than in the other OLIF models. The stresses of several important components of the OLIF + UPSF and OLIF + TFJF + UPSF models were between those of the OLIF + LPF and OLIF + BPSF models.

Conclusions

Our biomechanical FE analysis indicated the greater ability of OLIF + BPSF to retain lumbar stability, resist cage subsidence, and maintain disc height. Therefore, in the augmentation of OLIF, bilateral pedicle screws fixation may be the best approach.

Prospective multicenter study of minimally invasive surgery for the treatment of adult spinal deformity

OBJECTIVE

Traditional surgery for adult spinal deformity (ASD) is effective but may result in exposure-related morbidity. Minimally invasive surgery (MIS) can potentially minimize this morbidity; however, high-level evidence is lacking. This study presents the first prospective multicenter investigation of MIS approaches for ASD.

METHODS

A prospective multicenter study was conducted. Inclusion criteria were age ≥ 18 years, with at least one of the following radiographic criteria: coronal Cobb (CC) angle ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic tilt (PT) > 25°, and thoracic kyphosis > 60°. Additional inclusion criteria were circumferential MIS, including interbody fusion (transforaminal lumbar interbody fusion [TLIF], lateral lumbar interbody fusion [LLIF], or anterior lumbar interbody fusion [ALIF]) with percutaneous posterior fixation on a minimum of 4 intervertebral levels. Radiographic and clinical outcomes (visual analog scale [VAS], Oswestry Disability Index [ODI], and Scoliosis Research Society–22 [SRS-22]) were collected preoperatively and at 12 months postoperatively; preoperative and postoperative values were compared using paired Student t-tests.

RESULTS

Seventy-five patients with a minimum 1-year follow-up were identified (75 of 111; 67.6%). The mean ± SD age was 68.8 ± 9.0 years, and 48 patients (64%) were female. Patients underwent a mean of 6.7 ± 2.9 levels of fusion with LLIF (85%), ALIF (55%), and TLIF (9%); the mean estimated blood loss was 547.6 ± 567.2 mL, and the mean length of stay was 7.0 ± 3.7 days. Significant improvements were observed in ODI (−19 ± 12.9, p < 0.001), SRS-22 (0.8 ± 0.66, p < 0.001), VAS back (−4.3 ± 2.8, p < 0.001), and VAS leg (−3.0 ± 3.2, p < 0.001) scores. Significant decreases in SVA (−26.4 ± 53.6 mm; p < 0.001), pelvic incidence–lumbar lordosis (−11.3° ± 14.9°, p < 0.001), and CC angle (−12.1° ± 11.8°, p < 0.001) were also observed. Complications occurred in 39 patients (52%); 11 patients (15%) experienced major complications, and 16 patients (21%) required reoperation.

CONCLUSIONS

MIS approaches for ASD resulted in meaningful symptomatic improvement. The complication rates were similar to historic norms, with a fairly high reoperation rate at 1 year. Longer follow-up will be necessary to evaluate the durability of this approach in the treatment of ASD.

Fiducial marker recovery and detection from severely truncated data in navigation assisted spine surgery

PURPOSE

Fiducial markers are commonly used in navigation assisted minimally invasive spine surgery and they help transfer image coordinates into real world coordinates. In practice, these markers might be located outside the field-of-view (FOV) of C-arm cone-beam computed tomography (CBCT) systems used in intraoperative surgeries, due to the limited detector sizes. As a consequence, reconstructed markers in CBCT volumes suffer from artifacts and have distorted shapes, which sets an obstacle for navigation.

METHODS

In this work, we propose two fiducial marker detection methods: direct detection from distorted markers (direct method) and detection after marker recovery (recovery method). For direct detection from distorted markers in reconstructed volumes, an efficient automatic marker detection method using two neural networks and a conventional circle detection algorithm is proposed. For marker recovery, a task-specific data preparation strategy is proposed to recover markers from severely truncated data. Afterwards, a conventional marker detection algorithm is applied for position detection. The networks in both methods are trained based on simulated data. For the direct method, 6800 images and 10000 images are generated respectively to train the U-Net and ResNet50. For the recovery method, the training set includes 1360 images for FBPConvNet and Pix2pixGAN. The simulated data set with 166 markers and 4 cadaver cases with real fiducials are used for evaluation.

RESULTS

The two methods are evaluated on simulated data and real cadaver data. The direct method achieves 100% detection rates within 1 mm detection error on simulated data with normal truncation and simulated data with heavier noise, but only detect 94.6% markers in extremely severe truncation case. The recovery method detects all the markers successfully in three test data sets and around 95% markers are detected within 0.5 mm error. For real cadaver data, both methods achieve 100% marker detection rates with mean registration error below 0.2 mm.

CONCLUSIONS

Our experiments demonstrate that the direct method is capable of detecting distorted markers accurately and the recovery method with the task-specific data preparation strategy has high robustness and generalizability on various data sets. The task-specific data preparation is able to reconstruct structures of interest outside the FOV from severely truncated data better than conventional data preparation. This article is protected by copyright. All rights reserved.

Comparison of Hybrid Posterior Fixation and Conventional Open Posterior Fixation Combined with Multilevel Lateral Lumbar Interbody Fusion for Adult Spinal Deformity

We compared radiological and clinical outcomes between multilevel lateral lumbar interbody fusion (LLIF) + hybrid posterior fixation (PF) and multilevel LLIF + conventional open PF in patients with adult spinal deformity (ASD). Patients who underwent minimally invasive surgery for ASD in a single institution between 2014 and 2018 were retrospectively reviewed. Fifty-six patients (hybrid PF, 30; open PF, 26) who underwent ASD correction surgery were enrolled between 2014 and 2018. We evaluated patients’ demographics, clinical outcomes, and radiographical parameters in each group. There was significantly less estimated blood loss in the hybrid PF group (662.8 mL vs. 1088.8 mL; p = 0.012). The CRP level 7 days after surgery was significantly lower in the hybrid PF group (2.9 mg/dL vs. 4.3 mg/dL; p = 0.035). There was no significant difference between the two groups in other demographic variables, visual analog scores for back pain and leg pain, Oswestry Disability Index, coronal Cobb angle, lumbar lordosis, pelvic tilt, pelvic incidence–lumbar lordosis mismatch, and sagittal vertical axis. There was a significantly higher percentage of major complications in the open PF group (42.3% vs. 13.3%; p = 0.039). Thus, LLIF + hybrid PF for ASD corrective surgery may be comparable to LLIF + open PF in terms of clinical and radiographic outcomes.

Two- and three-year outcomes of minimally invasive and hybrid correction of adult spinal deformity

OBJECTIVE

Previous studies have demonstrated the short-term radiographic and clinical benefits of circumferential minimally invasive surgery (cMIS) and hybrid (i.e., minimally invasive anterior or lateral interbody fusion with an open posterior approach) techniques to correct adult spinal deformity (ASD). However, it is not known if these benefits are maintained over longer periods of time. This study evaluated the 2- and 3-year outcomes of cMIS and hybrid correction of ASD.

METHODS

A multicenter database was retrospectively reviewed for patients undergoing cMIS or hybrid surgery for ASD. Patients were ≥ 18 years of age and had one of the following: maximum coronal Cobb angle (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic incidence-lumbar lordosis mismatch (PI-LL) ≥ 10°, or pelvic tilt (PT) > 20°. Radiographic parameters were evaluated at the latest follow-up. Clinical outcomes were compared at 2- and 3-year time points and adjusted for age, preoperative CC, levels operated, levels with interbody fusion, presence of L5-S1 anterior lumbar interbody fusion, and upper and lower instrumented vertebral level.

RESULTS

Overall, 197 (108 cMIS, 89 hybrid) patients were included with 187 (99 cMIS, 88 hybrid) and 111 (60 cMIS, 51 hybrid) patients evaluated at 2 and 3 years, respectively. The mean (± SD) follow-up duration for cMIS (39.0 ± 13.3 months, range 22-74 months) and hybrid correction (39.9 ± 16.8 months, range 22-94 months) were similar for both cohorts. Hybrid procedures corrected the CC greater than the cMIS technique (adjusted p = 0.022). There were no significant differences in postoperative SVA, PI-LL, PT, and sacral slope (SS). At 2 years, cMIS had lower Oswestry Disability Index (ODI) scores (adjusted p < 0.001), greater ODI change as a percentage of baseline (adjusted p = 0.006), less visual analog scale (VAS) back pain (adjusted p = 0.006), and greater VAS back pain change as a percentage of baseline (adjusted p = 0.001) compared to hybrid techniques. These differences were no longer significant at 3 years. At 3 years, but not 2 years, VAS leg pain was lower for cMIS compared to hybrid techniques (adjusted p = 0.032). Those undergoing cMIS had fewer overall complications compared to hybrid techniques (adjusted p = 0.006), but a higher odds of pseudarthrosis (adjusted p = 0.039).

CONCLUSIONS

In this review of a multicenter database for patients undergoing cMIS and hybrid surgery for ASD, hybrid procedures were associated with a greater CC improvement compared to cMIS techniques. cMIS was associated with superior ODI and back pain at 2 years, but this difference was no longer evident at 3 years. However, cMIS was associated with superior leg pain at 3 years. There were fewer complications following cMIS, with the exception of pseudarthrosis.

Role of Robotics in Adult Spinal Deformity

Robotic-assisted adult deformity surgery has played a rapidly expanding role since its introduction. As robotic spine technologies improve, the potential to limit complications and morbidity is vast. The improvements in instrumentation accuracy combined with the ability to maintain that accuracy in multiple positions allow creative surgical approaches and techniques that can limit operative time, blood loss, and improve outcomes. In the years to come, robotic-assisted spine surgery and navigation will likely play an expanding role that continues to be defined. LEVEL OF EVIDENCE: 5, expert opinion.

Comparison of Minimally Invasive Lateral Lumbar Interbody Fusion, Minimally Invasive Lateral Lumbar Interbody Fusion, and Open Posterior Lumbar Interbody Fusion in the Treatment of Single-Level Spondylolisthesis of L4-L5

OBJECTIVE

To compare the outcomes of minimally invasive lateral lumbar interbody fusion (LLIF) with minimally invasive transforaminal lumbar interbody fusion (TLIF) and conventional open posterior lumbar interbody fusion (PLIF) for treating single-level spondylolisthesis at L4-L5.

METHODS

The patients underwent minimally invasive LLIF (n = 18), minimally invasive TLIF (n = 17), and conventional open PLIF (n = 20) for spondylolisthesis at L4-L5. Reduction of slippage, improvement in segmental lordosis, and restoration of foraminal height were measured. Perioperative parameters such as blood loss and operation time and clinical outcomes such as visual analog scale score and Oswestry Disability Index were compared.

RESULTS

Compared with the open PLIF group, the minimally invasive LLIF group showed greater restoration of mean foraminal height, significantly smaller mean intraoperative estimated blood loss, and less mean hemoglobin reduction on the third day postoperatively. Compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed greater restoration of mean segmental lordosis. The minimally invasive LLIF group showed a significantly shorter mean time to start walking after surgery compared with the conventional open PLIF and minimally invasive TLIF groups. However, compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed a significantly longer mean operating time. Clinical outcomes were not statistically different among the 3 groups.

CONCLUSIONS

In the treatment of spondylolisthesis of L4-L5, minimally invasive LLIF provided an effective surgical alternative to minimally invasive TLIF or conventional open PLIF, with the advantages of less blood loss, the faster start of postoperative walking, and comparable improvement in radiologic parameters.

Less Invasive Pediatric Spinal Deformity Surgery: The Case for Robotic-Assisted Placement of Pedicle Screws

Introduction: Pediatric spinal deformity involves a complex 3-dimensional (3D) deformity that increases the risk of pedicle screw placement due to the close proximity of neurovascular structures. To increase screw accuracy, improve patient safety, and minimize surgical complications, the placement of pedicle screws is evolving from freehand techniques to computer-assisted navigation and to the introduction of robotic-assisted placement. Purpose: The aim of this review was to review the current literature on the use of robotic navigation in pediatric spinal deformity surgery to provide both an error analysis of these techniques and to provide recommendations to ensure its safe application. Methods: A narrative review was conducted in April 2021 using the MEDLINE (PubMed) database. Studies were included if they were peer-reviewed retrospective or prospective studies, included pediatric patients, included a primary diagnosis of pediatric spine deformity, utilized robotic-assisted spinal surgery techniques, and reported thoracic or lumbar pedicle screw breach rates or pedicle screw malpositioning. Results: In the few studies published on the use of robotic techniques in pediatric spinal deformity surgery, several found associations between the technology and increased rates of screw placement accuracy, reduced rates of breach, and minimal complications. All were retrospective studies. Conclusions: Current literature is of a low level of evidence; nonetheless, the findings suggest the accuracy and safety of robotic-assisted spinal surgery in pediatric pedicle screw placement. The introduction of robotics may drive further advances in less invasive pediatric spinal deformity surgery. Further study is warranted.

Assessment of 3D Lumbosacral Vascular Anatomy for OLIF51 by Non-Enhanced MRI and CT Medical Image Fusion Technique

Study design: Prospective study. Objective: Medical image fusion can provide information from multiple modalities in a single image. The present study aimed to determine whether three-dimensional (3D) lumbosacral vascular anatomy could be adequately portrayed using a non-enhanced CT–MRI medical image fusion technique. Summary of Background Data: Lateral lumbar interbody fusion has gained popularity for the surgical treatment of adult spinal deformity (ASD). Oblique lumbar interbody fusion at L5–S1 (OLIF51) is receiving considerable attention as a method of creating good L5–S1 lordosis. Access in OLIF51 requires evaluation of the vascular anatomy in the lumbosacral region. Conventional imaging modalities need a contrast medium to describe the vascular anatomy. Methods: Participants comprised 15 patients with ASD or degenerative lumbar disease who underwent corrective surgery at our hospital between January 2020 and June 2021. A 3D vascular image with bony structures was obtained by fusing results from MRI and CT. We processed the merged image and measured the distance between left and right common iliac arteries and veins at two levels: the lower end of the L5 vertebral body (Window A) and the upper end of the S1 vertebral body (Window B). Results: The mean sizes of Window A and Window B were 29.7 ± 10.7 mm and 36.9 ± 10.3 mm, respectively. The mean distance from the bifurcation to the lower end of the L5 vertebra was 23.7 ± 10.9 mm. Coronal deviation of the bifurcation was, from center to left, 12.6 ± 12.3 mm, and the distance from the center of the L5 vertebral body to the bifurcation was 0.79 ± 7.3 mm. Only one case showed a median sacral vein (6.7%). Clinically, we performed OLIF51 in 12 of the 15 cases (80%). Conclusion: Evaluating 3D lumbosacral vascular anatomy using a non-enhanced MRI and CT medical image fusion technique is very useful for OLIF51, particularly for patients in whom the use of contrast medium is contraindicated.

The Scoli-RISK 1 results of lower extremity motor function 5 years after complex adult spinal deformity surgery

INTRODUCTION

Neurologic complications after complex adult spinal deformity (ASD) surgery are important, yet outcomes are heterogeneously reported, and long-term follow-up of actual lower extremity motor function is unknown.

OBJECTIVE

To prospectively evaluate lower extremity motor function scores (LEMS) before and at 5 years after surgical correction of complex ASD.

DESIGN

Retrospective analysis of a prospective, multicenter, international observational study.

METHODS

The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers around the world. Inclusion criteria were Cobb angle of > 80°, corrective osteotomy for congenital or revision deformity and/or 3-column osteotomy. Among patients with 5-year follow-up, comparisons of LEMS to baseline and within each follow-up period were made via documented neurologic exams on each patient.

RESULTS

Seventy-seven (28.3%) patients had 5-year follow-up. Among these 77 patients with 5-year follow-up, rates of postoperative LEMS deterioration were: 14.3% hospital discharge, 10.7% at 6 weeks, 6.5% at 6 months, 9.5% at 2 years and 9.3% at 5 years postoperative. During the 2-5 year window, while mean LEMS did not change significantly (-0.5, p = 0.442), eight (11.1%) patients deteriorated (of which 3 were ≥ 4 motor points), and six (8.3%) patients improved (of which 2 were ≥ 4 points). Of the 14 neurologic complications, four (28.6%) were surgery-related, three of which required reoperation. While mean LEMS were not impacted in patients with a major surgery-related complication, mean LEMS were significantly lower in patients with neurologic surgery-related complications at discharge (p = 0.041) and 6 months (p = 0.008) between the two groups as well as the change from baseline to 5 years (p = 0.041).

CONCLUSIONS

In 77 patients undergoing complex ASD surgery with 5-year follow-up, while mean LEMS did not change from 2 to 5 years, subtle neurologic changes occurred in approximately 1 in 5 patients (11.1% deteriorated; 8.3% improved). Major surgery-related complication did not result in decreased LEMS; however, those with neurologic surgery-related complications continued to have decreased lower extremity motor function at 5 years postoperative. These results underscore the importance of long-term follow-up to 5 years, using individual motor scores rather than group averages, and comparing outcomes to both baseline and last follow-up.

Factors affecting approach selection for minimally invasive versus open surgery in the treatment of adult spinal deformity: analysis of a prospective, nonrandomized multicenter study

OBJECTIVE

Surgical decision-making and planning is a key factor in optimizing outcomes in adult spinal deformity (ASD). Minimally invasive spinal (MIS) strategies for ASD have been increasingly used as an option to decrease postoperative morbidity. This study analyzes factors involved in the selection of either a traditional open approach or a minimally invasive approach to treat ASD in a prospective, nonrandomized multicenter trial. All centers had at least 5 years of experience in minimally invasive techniques for ASD.

METHODS

The study enrolled 268 patients, of whom 120 underwent open surgery and 148 underwent MIS surgery. Inclusion criteria included age ≥ 18 years, and at least one of the following criteria: coronal curve (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic tilt (PT) > 25°, or thoracic kyphosis (TK) > 60°. Surgical approach selection was made at the discretion of the operating surgeon. Preoperative significant differences were included in a multivariate logistic regression analysis to determine odds ratios (ORs) for approach selection.

RESULTS

Significant preoperative differences (p < 0.05) between open and MIS groups were noted for age (61.9 vs 66.7 years), numerical rating scale (NRS) back pain score (7.8 vs 7), CC (36° vs 26.1°), PT (26.4° vs 23°), T1 pelvic angle (TPA; 25.8° vs 21.7°), and pelvic incidence-lumbar lordosis (PI-LL; 19.6° vs 14.9°). No significant differences in BMI (29 vs 28.5 kg/m2), NRS leg pain score (5.2 vs 5.7), Oswestry Disability Index (48.4 vs 47.2), Scoliosis Research Society 22-item questionnaire score (2.7 vs 2.8), PI (58.3° vs 57.1°), LL (38.9° vs 42.3°), or SVA (73.8 mm vs 60.3 mm) were found. Multivariate analysis found that age (OR 1.05, p = 0.002), VAS back pain score (OR 1.21, p = 0.016), CC (OR 1.03, p < 0.001), decompression (OR 4.35, p < 0.001), and TPA (OR 1.09, p = 0.023) were significant factors in approach selection.

CONCLUSIONS

Increasing age was the primary driver for selecting MIS surgery. Conversely, increasingly severe deformities and the need for open decompression were the main factors influencing the selection of traditional open surgery. As experience with MIS surgery continues to accumulate, future longitudinal evaluation will reveal if more experience, use of specialized treatment algorithms, refinement of techniques, and technology will expand surgeon adoption of MIS techniques for adult spinal deformity.

Overview of Minimally Invasive Spine Surgery

Minimally invasive spine surgery (MISS) has continued to evolve over the past few decades, with significant advancements in technology and technical skills. From endonasal cervical approaches to extreme lateral lumbar interbody fusions, MISS has showcased its usefulness across all practice areas of the spine, with unique points of access to avoid pertinent neurovascular structures. Adult spine deformity has also recognized the importance of minimally invasive techniques in its ability to limit complications and to provide adequate sagittal alignment correction and improvements in patients' functional status. Although MISS has continued to make significant progress clinically, consideration must also be given to its economic impact and the learning curve surgeons experience in adding these procedures to their armamentarium. This review examines current innovations in MISS, as well as the economic impact and future directions of the field.

Intermediate-term clinical and radiographic outcomes with less invasive adult spinal deformity surgery: patients with a minimum follow-up of 4 years

BACKGROUND

Little information exists regarding longer-term outcomes with minimally invasive spine surgery (MISS), particularly regarding long-segment and deformity procedures. We aimed to evaluate intermediate-term outcomes of MISS for adult spinal deformity (ASD).

METHODS

This retrospective review of a prospectively collected multicenter database examined outcomes at 4 or more years following circumferential MIS (cMIS) or hybrid (HYB) surgery for ASD. A total of 53 patients at 8 academic centers satisfied the following inclusion criteria: age > 18 years and coronal Cobb > 20°, pelvic incidence-lumbar lordosis (PI-LL) > 10°, or sagittal vertical axis (SVA) > 5 cm.

RESULTS

Radiographic outcomes demonstrated improvements of PI-LL from 16.8° preoperatively to 10.8° and coronal Cobb angle from 38° preoperatively to 18.2° at 4 years. The incidence of complications over the follow-up period was 56.6%. A total of 21 (39.6%) patients underwent reoperation in the thoracolumbar spine, most commonly for adjacent level disease or proximal junctional kyphosis, which occurred in 11 (20.8%) patients. Mean Oswestry Disability Index (ODI) at baseline and years 1 through 4 were 49.9, 33.1, 30.2, 32.7, and 35.0, respectively. The percentage of patients meeting minimal clinically important difference (MCID) (defined as 12% or more from baseline) decreased over time, with leg pain reduction more durable than back pain reduction.

CONCLUSIONS

Intermediate-term clinical and radiographic improvement following MISS for ASD is sustained, but extent of improvement lessens over time. Outcome variability exists within a subset of patients not meeting MCID, which increases over time after year two. Loss of improvement over time was more notable in back than leg pain. However, average ODI improvement meets MCID at 4 years after MIS ASD surgery.

The MISDEF2 algorithm: an updated algorithm for patient selection in minimally invasive deformity surgery

OBJECTIVE

Minimally invasive surgery (MIS) can be used as an alternative or adjunct to traditional open techniques for the treatment of patients with adult spinal deformity. Recent advances in MIS techniques, including advanced anterior approaches, have increased the range of candidates for MIS deformity surgery. The minimally invasive spinal deformity surgery (MISDEF2) algorithm was created to provide an updated framework for decision-making when considering MIS techniques in correction of adult spinal deformity.

METHODS

A modified algorithm was developed that incorporates a patient’s preoperative radiographic parameters and leads to one of 4 general plans ranging from basic to advanced MIS techniques to open deformity surgery with osteotomies. The authors surveyed 14 fellowship-trained spine surgeons experienced with spinal deformity surgery to validate the algorithm using a set of 24 cases to establish interobserver reliability. They then re-surveyed the same surgeons 2 months later with the same cases presented in a different sequence to establish intraobserver reliability. Responses were collected and analyzed. Correlation values were determined using SPSS software.

RESULTS

Over a 3-month period, 14 fellowship-trained deformity surgeons completed the surveys. Responses for MISDEF2 algorithm case review demonstrated an interobserver kappa of 0.85 for the first round of surveys and an interobserver kappa of 0.82 for the second round of surveys, consistent with substantial agreement. In at least 7 cases, there was perfect agreement between the reviewing surgeons. The mean intraobserver kappa for the 2 surveys was 0.8.

CONCLUSIONS

The MISDEF2 algorithm was found to have substantial inter- and intraobserver agreement. The MISDEF2 algorithm incorporates recent advances in MIS surgery. The use of the MISDEF2 algorithm provides reliable guidance for surgeons who are considering either an MIS or an open approach for the treatment of patients with adult spinal deformity.

The clinical and radiological outcomes of multilevel posterior lumbar interbody fusion in the treatment of degenerative scoliosis: a consecutive case series with minimum 2 years follow up

Background

Surgical treatment for adult degenerative scoliosis (ADS) is a complex undertaking and is associated with a high complication rate. Our aim was to evaluate the clinical and radiological outcomes, mortality and morbidity of multilevel posterior lumbar interbody fusion (MPLIF) in the treatment in ADS based on the experience of a single tertiary referral center for spinal surgery.

Methods

We performed a retrospective analysis of prospectively collected data of consecutive patients who had undergone multi-level posterior interbody fusion for degenerative scoliosis. We prospectively recorded patients' demographics, co-morbidities; coronal and sagittal plane deformity assessment and surgical details: number of instrumented levels, and intra-operative and postoperative complications. Functional outcomes and patient-reported complications were entered in our local spine surgery database (part of the Eurospine Spine Tango Registry) and used to collect data on functional scores and patient-reported complications preoperatively and at 6, 12 and 24 months' follow-up.

Results

Our study involved 13 males and 51 females with a mean age of 70.26 (range 49-90, SD 8.9). MPLIF was performed at five levels in one patient, four levels in 29 patients, three levels in 20 patients, and two levels in 14 patients. There were a total of 14 (21.87%) major, minor and mechanical complications. There were no procedure-related mortalities. The average COMI and Eq5d scores improved significantly post-surgery, and this improvement was maintained at a mean follow-up of up to two years.

Conclusions

Multilevel posterior interbody fusion is a safe procedure, and in selected cases can result in good clinical and radiological outcomes with improvement in patient quality of life.

SURGERY FOR ADULT SPINAL SCOLIOSIS: DO THE BENEFITS OUTWEIGH THE RISKS?

ABSTRACT Around 6% of the elderly population over 65 years of age are affected by adult spinal deformity (ASD). The increasing prevalence of ASD with aging has prompted discussion regarding the use of various techniques for its treatment, such as surgery and conservative treatment. The objective of this study is to investigate whether surgical treatment demonstrates significant benefits as compared to conservative treatment. A literature review was conducted, focusing on the most relevant papers on the topic published in the last five years. Surgical treatment, which costs an average of US$ 99,114 per procedure, enables almost instant improvement of the pain and disability of ASD. The rate of perioperative complications in ASD is approximately 7.5%, and the average improvement in back pain is 6.2 times higher in the surgical approach than in conservative treatment. In addition, the use of modern operative techniques, such as minimally invasive surgery (MIS), reduces the complications and greatly improves patients’ quality of life, compared to open surgery. Therefore, the expected benefits of surgical treatment meets the patient’s expectations by eliminating the pain caused by ASD. Although surgical treatment has a higher cost and a greater risk of complications, the use of minimally invasive techniques give the ASD patient a better quality of life. Level of evidence III; Non-Systematic Review.

The Prevalence of the Use of MIS Techniques in the Treatment of Adult Spinal Deformity (ASD) Amongst Members of the Scoliosis Research Society (SRS) in 2016

STUDY DESIGN

Electronic survey administered to Scoliosis Research Society members.

OBJECTIVE

To determine the prevalence of minimally invasive surgery (MIS) techniques for the treatment of adult spinal deformity.

SUMMARY OF BACKGROUND DATA

There is a paucity of data available on the practice pattern, prevalence of minimally invasive spine surgery, and the preferred minimally invasive techniques in the treatment of adult spine deformity.

METHODS

An electronic nine-question survey regarding individual usage pattern of minimally invasive spine surgery techniques was administered in 2016 to the members of the Scoliosis Research Society. Determinants included complexity in condition of patient population, prevalence of use of minimally invasive techniques in the surgeon's practice, prevalence of use of a particular MIS technique, strategy elected during surgery, adoption of staging of procedures and timing between staging of procedures.

RESULTS

A total of 357 surgeons responded (61.3% response rate), and 154 (43.1%) of the respondents said that they use MIS as a part of their surgical treatment of adult spinal deformity. However, of these 154 respondents, 67 (43.5%) said that their MIS usage in deformity practice was between 1% and 20%. Only 11 (7.2%) said that they used MIS 81% to 100% of the time. The top MIS approaches that surgeons chose were MIS lateral lumbar interbody fusion 109 (70.59%) and MIS percutaneous screws 91 (58.8%).

CONCLUSIONS

The low rate of adoption of these techniques among the SRS members may be due to the false perception that there is not enough data to support that MIS techniques are better. This and the fact that a practitioner needs to be facile at different MIS techniques may be the true impediment to the adoption of MIS techniques in the treatment of ASD.

LEVEL OF EVIDENCE

Level IV.

Early and Late Reoperation Rates With Various MIS Techniques for Adult Spinal Deformity Correction

STUDY DESIGN

A multicenter retrospective review of an adult spinal deformity database.

OBJECTIVE

We aimed to characterize reoperation rates and etiologies of adult spinal deformity surgery with circumferential minimally invasive surgery (cMIS) and hybrid (HYB) techniques.

METHODS

Inclusion criteria were age ≥18 years, and one of the following: coronal Cobb >20°, sagittal vertical axis >5 cm, pelvic tilt >20°, and pelvic incidence-lumbar lordosis >10°. Patients with either cMIS or HYB surgery, ≥3 spinal levels treated with 2-year minimum follow-up were included.

RESULTS

A total of 133 patients met inclusion for this study (65 HYB and 68 cMIS). Junctional failure (13.8%) was the most common reason for reoperation in the HYB group, while fixation failure was the most common reason in the cMIS group (14.7%). There was a higher incidence of proximal junctional failure (PJF) than distal junctional failure (DJF) within HYB (12.3% vs 3.1%), but no significant differences in PJF or DJF rates when compared to cMIS. Early (<30 days) reoperations were less common (cMIS = 1.5%; HYB = 6.1%) than late (>30 days) reoperations (cMIS = 26.5%; HYB = 27.7%), but early reoperations were more common in the HYB group after propensity matching, largely due to infection rates (10.8% vs 0%, P = .04).

CONCLUSIONS

Adult spinal deformity correction with cMIS and HYB techniques result in overall reoperation rates of 27.9% and 33.8%, respectively, at minimum 2-year follow-up. Junctional failures are more common after HYB approaches, while pseudarthrosis/fixation failures happen more often with cMIS techniques. Early reoperations were less common than later returns to the operating room in both groups, but cMIS demonstrated less risk of infection and early reoperation when compared with the HYB group.

Clinical and Radiologic Fate of the Lumbosacral Junction After Anterior Lumbar Interbody Fusion Versus Axial Lumbar Interbody Fusion at the Bottom of a Long Construct in CMIS Treatment of Adult Spinal Deformity

Introduction:

Surgeons use numerous arthrodesis strategies for fusion of the lumbosacral junction including anterior lumbar interbody fusion (ALIF) and axial lumbar interbody fusion (AxiaLIF). The optimal L5-S1 fusion strategy remains inconclusive. The purpose of this study is to compare the fate of the lumbosacral junction in ALIF versus AxiaLIF patients in terms of clinical and radiographic outcomes.

Methods:

Adult spinal deformity patients, treated with CMIS techniques, with at least 2-year follow-up who underwent AxiaLIF or ALIF at the lumbosacral junction were included. Patients were separated into two groups: AxiaLIF (56 patients) and ALIF (38 patients). Outcome measures included segmental lordosis, sagittal vertical alignment, lumbar lordosis (LL), pelvic incidence–LL mismatch, and pseudarthrosis, major complication, and revision surgery rates.

Results:

The ALIF group achieved greater postoperative and delta segmental lordosis, higher delta sagittal vertical alignment, higher delta LL, and lower postoperative pelvic incidence–LL mismatch. The pseudarthrosis, major complication, and revision surgery rates were higher in the AxiaLIF group. Five cases of pseudarthrosis at L5-S1 were seen, all in the AxiaLIF group.

Discussion and Conclusion:

ALIF patients showed more favorable radiographic correction parameters and lower rates of pseudarthrosis, major complications, and revision surgeries. ALIF is the preferred strategy for L5-S1 arthrodesis at a bottom of a long construct.

Treatment of the Fractional Curve of Adult Scoliosis With Circumferential Minimally Invasive Surgery Versus Traditional, Open Surgery: An Analysis of Surgical Outcomes

STUDY DESIGN

Retrospective, multicenter review of adult scoliosis patients with minimum 2-year follow-up.

OBJECTIVE

Because the fractional curve (FC) of adult scoliosis can cause radiculopathy, we evaluated patients treated with either circumferential minimally invasive surgery (cMIS) or open surgery.

METHODS

A multicenter retrospective adult deformity review was performed. Patients included: age >18 years with FC >10°, ≥3 levels of instrumentation, 2-year follow-up, and one of the following: coronal Cobb angle (CCA) > 20°, pelvic incidence and lumbar lordosis (PI-LL) > 10°, pelvic tilt (PT) > 20°, and sagittal vertical axis (SVA) > 5 cm.

RESULTS

The FC was treated in 118 patients, 79 open and 39 cMIS. The FCs had similar coronal Cobb angles preoperative (17° cMIS, 19.6° open) and postoperative (7° cMIS, 8.1° open), but open had more levels treated (12.1 vs 5.7). cMIS patients had greater reduction in VAS leg (6.4 to 1.8) than open (4.3 to 2.5). With propensity matching 40 patients for levels treated (cMIS: 6.6 levels, N = 20; open: 7.3 levels, N = 20), both groups had similar FC correction (18° in both preoperative, 6.9° in cMIS and 8.5° postoperative). Open had more posterior decompressions (80% vs 22.2%, P < .001). Both groups had similar preoperative (Visual Analogue Scale [VAS] leg 6.1 cMIS and 5.4 open) and postoperative (VAS leg 1.6 cMIS and 3.1 open) leg pain. All cMIS patients had interbody grafts; 35% of open did. There was no difference in change of primary CCA, PI-LL, LL, Oswestry Disability Index, or VAS Back.

CONCLUSION

Patients' FCs treated with cMIS had comparable reduction of leg pain compared with those treated with open surgery, despite significantly fewer cMIS patients undergoing direct decompression.

The impact of age on surgical goals for spinopelvic alignment in minimally invasive surgery for adult spinal deformity

OBJECTIVE

Achieving appropriate spinopelvic alignment in deformity surgery has been correlated with improvement in pain and disability. Minimally invasive surgery (MIS) techniques have been used to treat adult spinal deformity (ASD); however, there is concern for inadequate sagittal plane correction. Because age can influence the degree of sagittal correction required, the purpose of this study was to analyze whether obtaining optimal spinopelvic alignment is required in the elderly to obtain clinical improvement.

METHODS

A multicenter database of ASD patients was queried. Inclusion criteria were age ≥ 18 years; an MIS component as part of the index procedure; at least one of the following: pelvic tilt (PT) > 20°, sagittal vertical axis (SVA) > 50 mm, pelvic incidence to lumbar lordosis (PI-LL) mismatch > 10°, or coronal curve > 20°; and minimum follow-up of 2 years. Patients were stratified into younger (< 65 years) and older (≥ 65 years) cohorts. Within each cohort, patients were categorized into aligned (AL) or mal-aligned (MAL) subgroups based on postoperative radiographic measurements. Mal-alignment was defined as a PI-LL > 10° or SVA > 50 mm. Pre- and postoperative radiographic and clinical outcomes were compared.

RESULTS

Of the 185 patients, 107 were in the younger cohort and 78 in the older cohort. Based on postoperative radiographs, 36 (33.6%) of the younger patients were in the AL subgroup and 71 (66.4%) were in the MAL subgroup. The older patients were divided into 2 subgroups based on alignment; there were 26 (33.3%) patients in the AL and 52 (66.7%) in the MAL subgroups. Overall, patients within both younger and older cohorts significantly improved with regard to postoperative visual analog scale (VAS) scores for back and leg pain and Oswestry Disability Index (ODI) scores. In the younger cohort, there were no significant differences in postoperative VAS back and leg pain scores between the AL and MAL subgroups. However, the postoperative ODI score of 37.9 in the MAL subgroup was significantly worse than the ODI score of 28.5 in the AL subgroup (p = 0.019). In the older cohort, there were no significant differences in postoperative VAS back and leg pain score or ODI between the AL and MAL subgroups.

CONCLUSIONS

MIS techniques did not achieve optimal spinopelvic alignment in most cases. However, age appears to impact the degree of sagittal correction required. In older patients, optimal spinopelvic alignment thresholds did not need to be achieved to obtain similar symptomatic improvement. Conversely, in younger patients stricter adherence to optimal spinopelvic alignment thresholds may be needed.

https://thejns.org/doi/abs/10.3171/2018.4.SPINE171153

Accuracy of the lateral cage placement under intraoperative C-arm fluoroscopy in oblique lateral interbody fusion

BACKGROUND

In oblique lateral interbody fusion (OLIF), the lateral cage enters into the disc space obliquely, and is then turned to the true lateral direction to achieve a lateral lumbar interbody fusion. The OLIF cage is sometimes placed asymmetrically although it seemed to be placed accurately on intraoperative C-arm images. The present study aimed to investigate the accuracy of cage placement and its effect on the radiological outcome in OLIF.

METHODS

This study involved a retrospective radiological analysis of 127 lateral cages in 75 consecutive OLIF patients. The cage deviations from the midline and cage obliquity were evaluated using three sets of images: (1) intraoperative C-arm fluoroscopy, (2) postoperative standing radiographs, and (3) postoperative computed tomography (CT).

RESULTS

The mean cage deviation from the midline was measured as 2.5 ± 2.7 mm on intraoperative C-arm images, but was found to be more deviated on postoperative radiographs and CT (5.4 ± 3.8 mm and 3.8 ± 3.7 mm; P = 0.000 and 0.005, respectively). The cage obliquity on the intraoperative lateral C-arm was minimal in 26 (20.5%) cases, mild in 69 (54.3%), and moderate in 32 (25.2%), but was found to be more obliquely on postoperative radiographs as minimal in 9 (7.1%), mild in 55 (43.3%), and moderate in 63 (49.6%) (P < 0.001). Anterior/posterior disc heights, disc lordotic angle, fusion rate, and cage subsidence rate were not different according to cage obliquity (all P > 0.05).

CONCLUSIONS

Cage deviation from the midline and obliquity is underestimated on intraoperative C-arm images in OLIF. Although minimal cage deviation and obliquity did not affect the radiological outcome, great care should be made for the orthogonal cage insertion.

Contribution of Lateral Interbody Fusion in Staged Correction of Adult Degenerative Scoliosis

Objective

Lateral interbody fusion (LIF) is attractive as a less invasive technique to address anterior spinal pathology in the treatment of adult spinal deformity. Its own uses and benefits in treatment of adult degenerative scoliosis are undefined. To investigate the radiographic and clinical outcomes of LIF, and staged LIF and posterior spinal fusion (PSF) for the treatment of adult degenerative scoliosis patients, we analyzed radiographic and clinical outcomes of adult degenerative scoliosis patients who underwent LIF and posterior spinal fusion.

Methods

Forty consecutive adult degenerative scoliosis patients who underwent LIF followed by staged PSF at a single institution were retrospectively reviewed. Long-standing 36” anterior-posterior and lateral radiographs were taken preoperatively, at inter-stage, 3 months, 1 year, and 2 years after surgery were reviewed. Outcomes were assessed through the visual analogue scale (VAS), 36-Item Short Form Health Survey (SF-36), and Oswestry Disability Index (ODI).

Results

Forty patients with a mean age of 66.3 (range, 49–79) met inclusion criteria. A mean of 3.8 levels (range, 2–5) were fused using LIF, while a mean of 9.0 levels (range, 3–16) were fused during the posterior approach. The mean time between stages was 1.4 days (range, 1–6). The mean follow-up was 19.6 months. Lumbar lordosis was significantly restored from 36.4º preoperatively up to 48.9º (71.4% of total correction) after LIF and 53.9º after PSF. Lumbar coronal Cobb was prominently improved from 38.6º preoperatively to 24.1º (55.8% of total correction) after LIF, 12.6º after PSF respectively. The mean pelvic incidence-lumbar lordosis mismatch was markedly improved from 22.2º preoperatively to 8.1º (86.5% of total correction) after LIF, 5.9º after PSF. Correction of coronal imbalance and sagittal vertebral axis did not reach significance. The rate of perioperative complication was 37.5%. Five patients underwent revision surgery due to wound infection. No major perioperative medical complications occurred. At last follow-up, there were significant improvements in VAS, SF-36 Physical Component Summary and ODI scores.

Conclusion

LIF provides significant corrections in the coronal and sagittal plane in the patients with adult degenerative scoliosis. However, LIF combined with staged PSF provides more excellent radiographic and clinical outcomes, with reduced perioperative risk in the treatment of adult degenerative scoliosis.

Extreme lateral lumbar interbody fusion (XLIF) in the management of degenerative scoliosis: a retrospective case series

Background

Surgical treatment of adult degenerative scoliosis (DS) always remains a challenge and often necessitates complex multilevel surgery via traditional open approaches. However, the severity of the procedure, in association with the fact that many of these patients are at an advanced age with several comorbidities, results in high rate of complications. Therefore, during the last decade, minimally invasive procedures have gained a place in the treatment of this pathology. Our aim is to determine the safety and efficacy of extra lateral lumbar interbody fusion (XLIF) with or without supplemented instrumentation in the treatment of DS.

Methods

In a retrospective case series study, we reviewed the files of patients who underwent XLIF in our Hospital between 2008 and 2017. We recorded the patients' demographic characteristics, clinical parameters such as back-pain [visual analogue scale (VAS)] and back-related disability [Oswestry Disability Index (ODI)], as well as radiological parameters including the Cobb angle. Comparison of the before and after results were performed with the t-test and Chi-square test, where appropriate.

Results

Twelve patients fulfilled the eligibility criteria of our study. All patients were female, with a mean age of 64.5 years (SD =7.8 years) and 28 months (SD =13 months) follow-up. The XLIF decreased the pain intensity by 4.66 cm (SD =1.23 cm), and improved the back-related disability by 26% (SD =8.35%) in the ODI scale at the 6-month follow-up. Similarly, scoliosis improved by an average of 11.5° (SD =7°) and lordosis changed by an average of 13.5° (SD =10.86°). All changes were statistically significant. There were three complications, two patients presented meralgia paresthetica, which resolved spontaneously in 3 months, and in one patient occurred an intraoperative bowel perforation treated with bowel anastomosis.

Conclusions

XLIF is a feasible and efficient alternative in the treatment of DS. It can be the treatment of choice in elderly patients in whom comorbidities increase the perioperative risk of complications.

Recent Advances in Technique and Clinical Outcomes of Minimally Invasive Spine Surgery in Adult Scoliosis

Objective:

Conventional open spinal surgery of adult scoliosis can be performed from anterior, posterior, or combined approach. Minimally invasive spine surgery (MISS) was developed for the purpose of reducing the undesirable effects and complications. This review aimed to make a brief summary of recent studies of the approach and clinical outcomes of MISS in adult scoliosis.

Data Sources:

We conducted a systematic search from PubMed, Medline, EMBASE, and other literature databases to collect reports of surgical methods and clinical outcomes of MISS in treatment of adult scoliosis. Those reports were published up to March 2017 with the following key terms: “minimally invasive,” “spine,” “surgery,” and “scoliosis.”

Study Selection:

The inclusion criteria of the articles were as followings: diagnosed with adult degenerative scoliosis (DS) or adult idiopathic scoliosis; underwent MISS or open surgery; with follow-up data. The articles involving patients with congenital scoliosis or unknown type were excluded and those without any follow-up data were also excluded from the study. The initial search yielded 233 articles. After title and abstract extraction, 29 English articles were selected for full-text review. Of those, 20 studies with 831 patients diagnosed with adult DS or adult idiopathic scoliosis were reviewed. Seventeen were retrospective studies, and three were prospective studies.

Results:

The surgical technique reported in these articles was direct or extreme lateral interbody fusion, axial lumbar interbody fusion, and transforaminal lumbar interbody fusion. Among the clinical outcomes of these studies, the operated levels was 3–7, operative time was 2.3–8.5 h. Both the Cobb angle of coronal major curve and evaluation of Oswestry Disability Index and Visual Analog Scale decreased after surgery. There were 323 complications reported in the 831 (38.9%) patients, including 150 (18.1%) motor or sensory deficits, and 111 (13.4%) implant-related complications.

Conclusions:

MISS can provide good radiological and self-evaluation improvement in treatment of adult scoliosis. More prospective studies will be needed before it is widely used.

Anatomical Modifications during the Lateral Transpsoas Approach to the Lumbar Spine. The Impact of Vertebral Rotation

Background

We investigated impact of vertebral axial rotation on neurovascular anatomy in adult spinal deformity (ASD) patients and provided recommendations on the approach based on degree of axial rotation. In order to isolate vertebral rotation (VR) impact from the superimposed degenerative cascade observed in adulthood, adolescent idiopathic scoliosis (AIS) patients were analyzed.

Methods

Magnetic resonance imaging (MRI) scans (L1-S1) from 50 right-convex thoracic (left-convex lumbar) AIS patients were analyzed. At each intervertebral level, VR, lumbar plexus depth (LPD), and vascular structure depth (VSD) were evaluated. Paired t test analyses were used to describe anatomic differences between the concave and convex aspect of our patients' curves. Correlation analysis was used to investigate relationships with soft tissue modifications and VR.

Results

Fifty AIS patients (17M, 33F) with mean thoracic Cobb of 50.6° ± 17.0° and mean lumbar Cobb of 41.9° ± 13.0° were included. Mean VR at each level was L1-2 = -6.6°, L2-3 = -7.7°, L3-4 = -6.5°, L4-5 = -4.7°, L5-S1 = -2.6° (negative value denotes clockwise rotation). We found significant differences (P < .05) between concave-convex (right-left) LPD at each level (L1-2 = 3.7 mm, L2-3 = 5.1 mm, L3-4 = 4.2 mm, L4-5 = 2.2 mm, L5-S1 = 2.2 mm). Vascular structure depth was significantly different at L1-L2 (3.2 mm) and L5-S1 (3 mm). Significant correlation was found between increasing VR and concave-convex LPD difference (r = 0.68, P < .001).

Conclusions

This study demonstrates that displacement of the lumbar plexus is tied to the magnitude of VR in patients with AIS. When approaching the lumbar spine, this displacement widens the safe surgical corridor on the convex side and narrows the corridor on the concave side.

Level of Evidence

IV.

Clinical Relevance

Preoperative review of MRI scans should occur to assess the patient's safe surgical corridor for lateral lumbar interbody fusion (LLIF). Adult spinal deformity surgeons who approach a degenerated spine in patients with progressive AIS in adulthood must carefully plan for patient positioning, neurovascular anatomy, and realignment objectives prior to the day of surgical intervention.

Minimally Invasive Spinal Surgery for Adult Spinal Deformity

The purpose of this review is to present the current techniques and outcomes of adult spine deformity (ASD) surgery using the minimally invasive spine surgery (MISS) approach. We performed a systemic search of PubMed for literature published through January 2018 with the following terms: "minimally invasive spine surgery," "adult spinal deformity," and "degenerative scoliosis." Of the 138 items that were found through this search, 57 English-language articles were selected for full-text review. According to the severity of the deformity and the symptoms, various types of MISS have been utilized, such as MISS decompression, circumferential MISS, and hybrid surgery. With proper indications, the MISS approach achieved satisfactory clinical and radiological outcomes for ASD, with reduced complication rates. Future studies should aim to define clear indications for the application of various surgical options.

Minimally invasive spine surgery for degenerative spine disease and deformity correction: a literature review

During the last two decades, minimally invasive techniques and instruments in spine surgery have undergone serious development in all fields. Specific advantages of these minimally invasive methods have put them forward in spine surgery in recent times. Preservation of important anatomical structures of the spine is a major factor for the evolution of these procedures. The lower prevalence of complications and faster rehabilitation of patients are some of the advantages of minimally invasive spine surgery (MISS). Due to the increasing use of minimally invasive methods in the clinical practice worldwide, there is a strong need for clarification of basic principles, tips and tricks, complications, and clinical outcomes. This review is an effort to provide a better understanding of some of these procedures.

Pseudarthrosis in adult and pediatric spinal deformity surgery: a systematic review of the literature and meta-analysis of incidence, characteristics, and risk factors

We conducted a systematic review with meta-analysis and qualitative synthesis. This study aims to characterize pseudarthrosis after long-segment fusion in spinal deformity by identifying incidence rates by etiology, risk factors for its development, and common features. Pseudarthrosis can be a painful and debilitating complication of spinal fusion that may require reoperation. It is poorly characterized in the setting of spinal deformity. The MEDLINE, EMBASE, and Cochrane databases were searched for clinical research including spinal deformity patients treated with long-segment fusions reporting pseudarthrosis as a complication. Meta-analysis was performed on etiologic subsets of the studies to calculate incidence rates for pseudarthrosis. Qualitative synthesis was performed to identify characteristics of and risk factors for pseudarthrosis. The review found 162 articles reporting outcomes for 16,938 patients which met inclusion criteria. In general, the included studies were of medium to low quality according to recommended reporting standards and study design. Meta-analysis calculated an incidence of 1.4% (95% CI 0.9-1.8%) for pseudarthrosis in adolescent idiopathic scoliosis, 2.2% (95% CI 1.3-3.2%) in neuromuscular scoliosis, and 6.3% (95% CI 4.3-8.2%) in adult spinal deformity. Risk factors for pseudarthrosis include age over 55, construct length greater than 12 segments, smoking, thoracolumbar kyphosis greater than 20°, and fusion to the sacrum. Choice of graft material, pre-operative coronal alignment, post-operative analgesics, and sex have no significant impact on fusion rates. Older patients with greater deformity requiring more extensive instrumentation are at higher risk for pseudarthrosis. Overall incidence of pseudarthrosis requiring reoperation is low in adult populations and very low in adolescent populations.

Adult Degenerative Lumbar Scoliosis

Adult degenerative lumbar scoliosis is a 3-dimensional deformity defined as a coronal deviation of greater than 10°. It causes significant pain and disability in the elderly. With the aging of the population, the incidence of adult degenerative lumbar scoliosis will continue to increase. During the past decade, advancements in surgical techniques and instrumentation have changed the management of adult spinal deformity and led to improved long-term outcomes. In this article, the authors provide a comprehensive review of the pathophysiology, diagnosis, and management of adult degenerative lumbar scoliosis. [Orthopedics. 2017; 40(6):e930-e939.].

Minimally invasive techniques for lumbar decompressions and fusions

PURPOSE OF REVIEW

The purpose of this study is to summarize the recent literature investigating the use of minimally invasive (MIS) techniques in the treatment of lumbar degenerative stenosis, spondylolisthesis, and scoliosis.

RECENT FINDINGS

MIS lumbar decompression and fusion techniques for degenerative pathology are associated with reduced operative morbidity, shortened length of hospital stay, and reduced postoperative pain and narcotics utilization. Recent studies with long-term clinical follow-up have demonstrated equivalence in clinical outcomes between open and MIS surgical procedures. Radiographically, MIS procedures provide adequate postoperative correction of coronal alignment. Correction of sagittal alignment, however, is more variable based on current reports. MIS techniques are both safe and effective in the treatment of lumbar degenerative pathologies. While some studies have reported on long-term outcomes and costs associated with MIS procedures, more investigation into these topics is still necessary. Additionally, further work is required to analyze the training requirements and learning curves of MIS procedures to better promote adoption amongst surgeons.

Degenerative Scoliosis

PURPOSE OF REVIEW

The purpose of this review is to provide an updated review of adult degenerative scoliosis (ADS). Epidemiology, classification, pathophysiology, and natural history are discussed along with a summary of commonly used outcome measures. Operative vs non-operative outcomes and new surgical techniques are discussed.

RECENT FINDINGS

The SRS-Schwab classification (2012) combines clinical and radiographic evaluation including overall global alignment. Current evidence regarding risk factors and efficacy of non-surgical modalities are discussed. Recent studies have reported surgical management to provide superior outcomes to non-operative modalities. New surgical techniques provide promising early data in regard to decreasing perioperative morbidity. ADS is a potentially debilitating condition that occurs with asymmetric spinal degeneration. This can produce global sagittal malalignment and central and foraminal stenosis and can lead to significant impairment often necessitating surgery. The surgeon must be aware of the perioperative risks in this population and implement appropriate age-specific alignment goals to achieve the best outcome for patients.

Is There a Patient Profile That Characterizes a Patient With Adult Spinal Deformity as a Candidate for Minimally Invasive Surgery?

STUDY DESIGN

Retrospective review.

OBJECTIVES

The goal of this study was to evaluate the baseline characteristics of patients chosen to undergo traditional open versus minimally invasive surgery (MIS) for adult spinal deformity (ASD).

METHODS

A multicenter review of 2 databases including ASD patients treated with surgery. Inclusion criteria were age >45 years, Cobb angle minimum of 20°, and minimum 2-year follow-up. Preoperative radiographic parameters and disability outcome measures were reviewed.

RESULTS

A total of 350 patients were identified: 173 OPEN patients and 177 MIS. OPEN patients were significantly younger than MIS patients (61.5 years vs 63.74 years, P = .013). The OPEN group had significantly more females (87% vs 76%, P = .006), but both groups had similar body mass index. Preoperative lumbar Cobb was significantly higher for the OPEN group (34.2°) than for the MIS group (26.0°, P < .001). The mean preoperative Oswestry Disability Index was significantly higher in the MIS group (44.8 in OPEN patients and 49.8 in MIS patients, P < .011). The preoperative Numerical Rating Scale value for back pain was 7.2 in the OPEN group and 6.8 in the MIS group preoperatively, P = .100.

CONCLUSIONS

Patients chosen for MIS for ASD are slightly older and have smaller coronal deformities than those chosen for open techniques, but they did not have a substantially lesser degree of sagittal malalignment. MIS surgery was most frequently utilized for patients with an sagittal vertical axis under 6 cm and a baseline pelvic incidence and lumbar lordosis mismatch under 30°.

Adult spinal deformity treated with minimally invasive surgery. Description of surgical technique, radiological results and literature review

The prevalence of adult spinal deformity has been increasing exponentially over time. Surgery has been credited with good radiological and clinical results. The incidence of complications is high. MIS techniques provide good results with fewer complications. This is a retrospective study of 25 patients with an adult spinal deformity treated by MIS surgery, with a minimum follow-up of 6 months. Radiological improvement was SVA from 5 to 2cm, coronal Cobb angle from 31° to 6°, and lumbar lordosis from 18° to 38°. All of these parameters remained stable over time. We also present the complications that appeared in 4 patients (16%). Only one patient needed reoperation. We describe the technique used and review the references on the subject. We conclude that the MIS technique for treating adult spinal deformity has comparable results to those of the conventional techniques but with fewer complications.

Analysis of Intraoperative Cone-Beam Computed Tomography Combined With Image Guidance for Lateral Lumbar Interbody Fusion

BACKGROUND

Minimally invasive lateral lumbar interbody fusion (LLIF) is traditionally performed with biplanar fluoroscopy. Recent literature demonstrates that intraoperative cone-beam computed tomography combined with spinal navigation can be safely utilized for localization and cage placement in LLIF.

OBJECTIVE

To evaluate the accuracy and safety of cage placement using spinal navigation in LLIF, as well as to evaluate the radiation exposure to surgeon and staff during the procedure.

METHODS

The authors performed a retrospective analysis of a prospectively acquired database of patients undergoing LLIF with image-based navigation performed from April 2014 to July 2016 at a single institution. The medical records were reviewed, and data on clinical outcomes, cage accuracy, complications, and radiation exposure were recorded. All patients underwent a minimum 30-d clinical follow-up to assess intraoperative and short-term complications associated with their LLIF.

RESULTS

Sixty-three patients comprising 117 spinal levels were included in the study. There were 36 (57.1%) female and 27 (42.9%) male patients. Mean age was 62.7 yr (range 24-79 yr). A mean 1.9 (range 1-4) levels per patient were treated. Cages were placed in the anterior or middle of 115 (98.3%) disc spaces. Image-guided cage trajectory was accurate in 116/117 levels (99.1%). In a subgroup analysis of 18 patients, mean fluoroscopy time was 11.7 ± 9.7 s per level. Sixteen (25.4%) patients experienced a complication related to approach.

CONCLUSION

Use of intraoperative cone-beam computed tomography combined with spinal navigation for LLIF results in accurate and safe cage placement as well as significantly decreased surgeon and staff radiation exposure.