Minimally invasive lumbar spinal fusion

Optimizing Single-Position Prone Lateral Lumbar Interbody Fusion with Exoscopic Technology: A Review of Key Innovations

Minimally invasive spine surgery has advanced significantly over the past decade, integrating technologies such as intraoperative navigation, robotics, and artificial intelligence with innovative techniques such as single-position prone lateral transpsoas lumbar interbody fusion (proLIF). While proLIF offers excellent clinical outcomes for a wide range of lumbar pathologies, the lateral approach to lumbar spine presents technical and ergonomic challenges, including an increased need for soft-tissue dissection and unfavorable ergonomics for surgeons. This review details how the combination of emerging technologies has been applied in minimally invasive lumbar spine surgery. It also describes the novel application of an exoscope during navigation-guided proLIF. The benefits offered by the exoscope included high-resolution, three-dimensional visualization, enhanced maneuverability, and improved surgeon ergonomics. By combining emerging technologies with novel surgical approaches, this review demonstrates the recent advancements in minimally invasive spine surgery and underscores the exoscope's potential to enhance visualization and optimize ergonomics for surgeons.

A New Pilot Hole Preparation System for Percutaneous Pedicle Screw Placement: A Randomized Controlled Study

STUDY DESIGN

A randomized controlled study.

OBJECTIVE

To introduce a new pilot hole preparation system for percutaneous pedicle screw placement and investigate its efficiency and safety in comparison with the conventional method.

SUMMARY OF BACKGROUND DATA

Placing screws accurately, rapidly, and safely with less radiation exposure is critical for minimally invasive lumbar interbody fusion (LIF). Optimizing pilot hole preparation instruments has important clinical implications.

MATERIALS AND METHODS

A total of 60 patients (180 screws) were included in this study. All patients were randomized into two groups (new system vs. conventional method) and performed single-level minimally invasive percutaneous fixation, interbody fusion, and unilateral decompression. Basic information, time of pilot hole preparation, time of screw placement, and fluoroscopy time were recorded. Screw placement accuracy was graded based on the Gertzbein-Robbins scale, and the angle between the screw axis and the pedicle axis was collected in postoperative CT.

RESULTS

There was no statistical difference in basic information between the 2 groups. The mean time of single pilot hole preparation was 4.08±1.01 minutes in the new system group and 5.34±1.30 minutes in the conventional method group ( P <0.001). The time of single screw placement was significantly shorter in the new system group (0.82±0.20 vs. 1.72±0.33 min), and the fluoroscopy time was also less in the new system group (13.70±3.42 vs. 19.95±5.50 s) ( P <0.001). Screw placement accuracy assessment showed that there were 85 (94.45%) A-grade screws in the new system group while 76 (84.44%) A-grade screws in the conventional method group ( P =0.027).

CONCLUSIONS

The new pilot hole preparation system has shown significant reductions in the time of pilot hole preparation, time of screw placement, and radiation exposure, and has good clinical application value.

Risk factors for low back pain after oblique lumbar interbody fusion in patients with low-grade degenerative lumbar spondylolisthesis: a retrospective study

Objective

To investigate the risk factors of low back pain after oblique lumbar interbody fusion (OLIF) in patients with low grade degenerative lumbar spondylolisthesis (DLS).

Methods

This retrospective study included 116 patients with single-level low-grade lumbar spondylolisthesis with low back pain who underwent OLIF surgery in our hospital from December 2017 to October 2020. Demographic, clinical, surgical, and radiological characteristics of this population were analyzed to determine the relationship between these characteristics and the degree of low back pain relief after OLIF.

Results

A total of 116 patients (average age 58.61 ± 7.01 years) were included in this study. Among them, 33 patients had poor improvement of low back pain after surgery, and 83 patients had satisfactory effect after surgery with obvious relief of low back pain. Postoperative disc height increase ≤2.5 mm (P = 0.000) was most correlated with poor improvement of low back pain symptoms after OLIF. The factors positively correlated with poor improvement of low back pain symptoms after OLIF in patients with low-grade degenerative lumbar spondylolisthesis included the increase of spondylolisthesis grade (OR = 17.665; 95%CI: 3.262-95.678 P = 0.001), disc height increase ≤2.5 mm (OR = 34.377; 95%CI: 5.632-209.818 P = 0.000). The factors negatively correlated with poor improvement of low back pain symptoms after OLIF in patients with low-grade degenerative lumbar spondylolisthesis included no osteoporosis (OR = 0.067; 95%CI: 0.013-0.350 P = 0.001), no cage subsidence (OR = 0.208; 95%CI: 0.048-0.903 P = 0.036), duration of preoperative low back pain symptoms ≤36 months (OR = 0.045; 95%CI: 0.007-0.277 P = 0.001).

Conclusions

OLIF can significantly improve the low back pain symptoms in patients with low-grade degenerative lumbar spondylolisthesis. High grade of spondylolisthesis before operation, duration of low back pain symptoms more than 36 months, osteoporosis, postoperative cage subsidence, and postoperative segmental disc height improvement less than 2.5 mm are risk factors for low back pain after operation.

Radiographic Robustness of Lumbar Interbody Fusion Techniques

STUDY DESIGN

Retrospective chart review.

OBJECTIVES

Lumbar interbody fusion (LIF) can be achieved with various techniques. Evidence supporting the long-term clinical advantages of one technique over another are inconclusive. The purpose of this study was to (1) determine the changes in sagittal parameters in the preoperative, intraoperative, and post-operative phase, (2) evaluate the radiographic maintenance of these parameters over time, and (3) compare the demographics and patient reported outcomes of patients undergoing various LIF techniques.

METHODS

We performed a retrospective chart review of patients with degenerative spine disease undergoing single level anterior (ALIF), lateral (LLIF), posterior (PLIF), or transforaminal (TLIF) lumbar interbody fusion. Data collected included patient demographics and diagnosis at time of surgery. Upright lumbar radiographs taken pre-operatively, intra-operatively, and post-operatively were measured for lumbar lordosis (LL), segmental lordosis (SL), posterior disc height (PDH), and foraminal height (FH).

RESULTS

194 patients in a single center were included. PDH and FH increased intra-operatively following ALIF (P < .0001), PLIF (P < .0001), LLIF (P < .0001), and TLIF (P < .0001). SL also increased intra-operatively for ALIF (P = .002) and LLIF (P = .0007). Compared to intra-operative radiographs, PDH and FH decreased at latest post-operative phase for ALIF (P < .03), LLIF (P < .003), TLIF (P < .001), and PLIF (P < .005). SL decreased for ALIF (P = .0008), and TLIF (P = .02). LL did not change postoperatively across techniques. Patient reported outcomes improved post-surgically and disability index decreased, but neither differed between techniques.

CONCLUSION

LIF, regardless of technique, was shown to provide significant radiographic changes in PDH and FH. Techniques utilizing larger intervertebral cage sizes (ALIF/LLIF) improved SL. Single level LIF did not affect overall LL. No single technique displayed superior radiographic robustness over time.

Efficacy evaluation of a minimally invasive surgical procedure (oblique lateral interbody fusion) for lumbar spinal tuberculosis-retrospective cohort study

Objective

In the current study, to demonstrate the advantages of oblique lateral interbody fusion (OLIF), we focused on the therapeutics for lumbar spinal tuberculosis with the comparison of three treatments, including anterior approach, posterior approach, and OLIF combined with posterior percutaneous pedicle screw fixation.

Methods

This study included patients with lumbar spinal tuberculosis from July 2015 to June 2018. We divided these patients into three groups: 35 patients underwent an anterior-only approach (Group A), 36 patients underwent a posterior-only approach (Group B), and 31 patients underwent OLIF combined with posterior percutaneous pedicle screw fixation (Group C). Operation time, blood loss, hospital stays, the visual analog scale (VAS) and the Oswestry disability index (ODI), ASIA grade, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and Cobb angle were used to evaluate the surgical approaches.

Results

A total of 102 patients joined this study of three therapeutic groups. The mean hospital stays, the mean operative time, and surgical blood loss of the three groups of patients were (14.40 ± 2.6, 14.00 ± 2.51, and 9.39 ± 1.86) days, (177.23 ± 13.23, 198.00 ± 16.75, and 150.39 ± 14.28) minutes, and (307.43 ± 21.91, 406.67 ± 27.02, and 105.97 ± 18.90) mL, respectively. VAS and ODI of all patients significantly improved 1 week after surgery (P < 0.05). As all patients received regular anti-tuberculosis treatment before and after surgery, ESR and CRP indicators maintained at normal levels 1 week after surgery. The Cobb angle was significantly corrected 1 week after surgery (P < 0.05). Eight patients had postoperative complications, and all of them recovered after active treatment.

Conclusion

OLIF combined with posterior percutaneous pedicle screw fixation has the advantages of less surgical trauma and faster postoperative recovery, although all three surgical approaches can achieve satisfactory clinical results.

Comparison of results among UBE-TLIF, MIS-TLIF and open TLIF for Meyerding grade I lumbar spondylolisthesis: a retrospective study

BACKGROUND

The unilateral biportal endoscopic (UBE) technique has garnered significant attention for its little paraspinal iatrogenic damage, expedited recovery, and low complication rates. This method is also applicable to open transforaminal lumbar interbody fusion (TLIF). Therefore, this study aimed to conduct a comparative analysis of the outcomes associated with unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF), minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and TLIF for Meyerding grade I lumbar spondylolisthesis.

METHODS

The study examined the outcomes of 79 patients with Meyerding grade I lumbar spondylolisthesis who underwent single-level intervertebral fusion. Clinical assessments included the measurement of pain levels using the Visual Analogue Scale (VAS) for low back and leg pain, the Oswestry Disability Index (ODI), surgical data, and demographic information. Imaging techniques were utilized to evaluate the fusion rate.

RESULTS

The VAS-Back demonstrated a statistically significant improvement in Group UBE-TLIF compared to the other groups at the one-week postoperative evaluation (p < .05). Additionally, the UBE-TLIF group exhibited a significantly longer total operative time compared to the other groups (p < .05). However, it was noted that the Postop Hemovac drain were significantly greater in the MIS-TLIF and TLIF groups compared to the UBE-TLIF group (p < .05).

CONCLUSIONS

The present research demonstrated the effectiveness of UBE-TLIF, MIS-TLIF, and TLIF as surgical approaches for treating Meyerding grade I lumbar spondylolisthesis. Among these methods, UBE-TLIF demonstrated a reduction in Postop Hemovac drain, and an increase in operative duration.

The Impact of Navigation in Lumbar Spine Surgery: A Study of Historical Aspects, Current Techniques and Future Directions

Background/Objectives: We sought to improve accuracy while minimizing radiation hazards, improving surgical outcomes, and preventing potential complications. Despite the increasing popularity of these systems, a limited number of papers have been published addressing the historical evolution, detailing the areas of use, and discussing the advantages and disadvantages, of this increasingly popular system in lumbar spine surgery. Our objective was to offer readers a concise overview of navigation system history in lumbar spine surgeries, the techniques involved, the advantages and disadvantages, and suggestions for future enhancements to the system. Methods: A comprehensive review of the literature was conducted, focusing on the development and implementation of navigation systems in lumbar spine surgeries. Our sources include PubMed-indexed peer-reviewed journals, clinical trial data, and case studies involving technologies such as computer-assisted surgery (CAS), image-guided surgery (IGS), and robotic-assisted systems. Results: To develop more practical, effective, and accurate navigation techniques for spine surgery, consistent advancements have been made over the past four decades. This technological progress began in the late 20th century and has since encompassed image-guided surgery, intraoperative imaging, advanced navigation combined with robotic assistance, and artificial intelligence. These technological advancements have significantly improved the accuracy of implant placement, reducing the risk of misplacement and related complications. Navigation has also been found to be particularly useful in tumor resection and minimally invasive surgery (MIS), where conventional anatomic landmarks are lacking or, in the case of MIS, not visible. Additionally, these innovations have led to shorter operative times, decreased radiation exposure for patients and surgical teams, and lower rates of reoperation. As navigation technology continues to evolve, future innovations are anticipated to further enhance the capabilities and accessibility of these systems, ultimately leading to improved patient outcomes in lumbar spine surgery. Conclusions: The initial limited utilization of navigation system in spine surgery has further expanded to encompass almost all fields of lumbar spine surgeries. As the cost-effectiveness and number of trained surgeons improve, a wider use of the system will be ensured so that the navigation system will be an indispensable tool in lumbar spine surgery. However, continued research and development, along with training programs for surgeons, are essential to fully realize the potential of these technologies in clinical practice.

Prospective Assessment of Transforaminal Lumbar Interbody Fusion (TLIF) in Spondylolisthesis: A Radiological and Functional Outcome Study in an Indian Population

INTRODUCTION

 Spondylolisthesis is a common spinal condition in which one vertebra slips over another, leading to pain and disability. Transforaminal lumbar interbody fusion (TLIF) has emerged as a surgical option for addressing spondylolisthesis; however, limited research exists, especially in the Indian context, evaluating its radiological and functional outcomes.

OBJECTIVE

 The study aimed to evaluate the radiological and functional outcomes of TLIF in spondylolisthesis using standardized scoring systems, to evaluate the sagittal balance of the spine radiologically in patients who have undergone TLIF for spondylolisthesis, and to evaluate the correlation between the functional and radiological outcomes after TLIF.

METHODS

 This prospective observational study included spondylolisthesis patients undergoing TLIF at SRM Medical College Hospital and Research Centre from August 2022 to August 2024. Criteria included Meyerding grade 1-4 spondylolisthesis, single-segment fusion, and willingness for 12-month follow-up.

RESULTS

 Forty-five patients were included with age 36.6 ± 12.2 years, with 73.3% being female. L4-L5 is the most common level affected in 21 patients (46.7%). Significant improvements were observed in pelvic tilt 19.07 ± 2.05, sacral slope 30.6 ± 4.4, segmental lordosis 18.4 ± 1.4, lumbar lordosis 57.1 ± 1.8, sagittal vertical axis (SVA) 2.5 ± 0.3, Visual Analog Scale for pain 0.4 ± 0.5, and Oswestry Disability Index (ODI) scores 5.23 ± 2.6 postoperatively (p < 0.05). At one-year follow-up, 84.4% of patients had good-to-excellent outcomes, and 44.4% had definitive fusion according to modified Lee criteria. However, there was no correlation between ODI score and grade of listhesis, pelvic incidence (PI), or SVA of the spine (p > 0.05).

CONCLUSION

 This study provides valuable insights into the effectiveness of TLIF surgery in addressing spondylolisthesis, both in terms of radiological and functional outcomes. However, there was no correlation between improvement in functional and radiological parameters (PI vs. ODI, SVA vs. ODI). TLIF appears to offer significant improvements in patient well-being and quality of life. These findings contribute to understanding TLIF's suitability as a treatment for spondylolisthesis and can inform clinical practice, ultimately benefiting patients suffering from this condition.

The efficacy of 3D gait analysis to evaluate surgical (and rehabilitation) outcome after degenerative lumbar surgery

BACKGROUND

Lumbar degenerative conditions are a major cause of back pain and disability in individuals aged 45 and above. Gait analysis utilizes sensor technology to collect movement data, aiding in the evaluation of various gait aspects like spatiotemporal parameters, joint angles, neuromuscular activity, and joint forces. It is widely used in conditions such as cerebral palsy and knee osteoarthritis. This research aims to assess the effectiveness of 3D gait analysis in evaluating surgical outcomes and postoperative rehabilitation for lumbar degenerative disorders.

METHODS

A prospective self-controlled before-after study (n = 85) carried out at our Hospital (Sep 2018 - Dec 2021) utilized a 3D motion analysis system to analyze gait in patients with lumbar degenerative diseases. The study focused on the multifidus muscle, a crucial spinal muscle, during a minimally invasive lumbar interbody fusion surgery conducted by Shandong Weigao Pharmaceutical Co., Ltd. Pre- and postoperative assessments included time-distance parameters (gait speed, stride frequency, stride length, stance phase), hip flexion angle, and stride angle. Changes in 3D gait parameters post-surgery and during rehabilitation were examined. Pearson correlation coefficient was employed to assess relationships with the visual analog pain scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) scores. Patient sagittal alignment was evaluated using "Surgimap" software from two types of lateral radiographs to obtain parameters like pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), intervertebral space height (DH), posterior height of the intervertebral space (PDH) at the operative segment, and anterior height of the intervertebral space (ADH).

RESULTS

By the 6th week post-operation, significant improvements were observed in the VAS score, JOA score, and ODI score of the patients compared to preoperative values (P < 0.05), along with notable enhancements in 3D gait quantification parameters (P < 0.05). Pearson correlation analysis revealed a significant positive correlation between improvements in 3D gait quantification parameters and VAS score, JOA score, and ODI value (all P < 0.001).

CONCLUSION

3D gait analysis is a valuable tool for evaluating the efficacy of surgery and rehabilitation training in patients.

A study on the 10-year trend of surgeries performed for lumbar disc herniation and comparative analysis of prescribed opioid analgesics and hospitalization duration: 2010-2019 HIRA NPS Data

BACKGROUND

This study, utilizing the claims data from the Health Insurance Review and Assessment Service of Korea, aimed to examine the 10-year (2010-2019) trends in various types of lumbar spine surgeries performed on patients diagnosed with lumbar herniated intervertebral disc (HIVD), and the current status of opioid prescriptions, as well as the duration of postoperative hospital stays based on the type of surgery performed.

METHOD

This retrospective cross-sectional study examined patients with one or more national health insurance claims carrying a primary or secondary diagnosis of HIVD (ICD-10 codes: M511, M518, M519) over a 10-year period (2010-2019). From the patients undergoing lumbar spine surgery, we selected those who did not require reoperation within 30 days following the initial lumbar surgery. Our final study sample comprised patients who underwent only one type of surgery.

RESULTS

Among the patients diagnosed with HIVD and subsequently undergoing lumbar surgery between 2010 and 2019, a slight downward trend was observed in those undergoing open discectomy (OD); however, OD persistently accounted for the highest proportion over the 10 years. Percutaneous endoscopic lumbar discectomy (PELD) demonstrated a consistent upward trend from 2016 to 2018. When inspecting trends, we noted a consistent escalation over the decade in the postoperative opioid prescription rates of strong opioids (50.7% in 2010 to 77.8% in 2019) and tramadol (50.9% in 2010 to 76.8% in 2019). Analyzing these trends by surgery type, spinal fusion exhibited a slightly higher rate of opioid prescriptions than other lumbar surgeries. Regarding the length of postoperative hospital stays, patients undergoing PELD recorded the shortest stay (7.04 ± 6.78 days), while spinal fusion necessitated the longest (20.14 ± 12.18 days).

CONCLUSION

This study analyzed the trends in types of lumbar spine surgeries, opioid analgesic prescriptions, and length of hospital stays over 10 years (2010-2019) among patients with HIVD in Korea. Our data and findings provide valuable evidence that may prove beneficial for clinicians and researchers involved in HIVD-related practices.

Different lumbar fusion techniques for lumbar spinal stenosis: a Bayesian network meta-analysis

OBJECTIVE

To comprehensively compare and assess the effects of different lumbar fusion techniques in patients with lumbar spinal stenosis (LSS).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were systematically searched up to December 24, 2022 in this network meta-analysis. Outcomes were pain (pain, low back pain, and leg pain), Japanese Orthopaedic Association (JOA), Oswestry Disability Index (ODI), complications, reoperation, and fusion. Network plots illustrated the direct and indirect comparisons of different fusion techniques for the outcomes. League tables showed the comparisons of any two fusion techniques, based on both direct and indirect evidence. The efficacy of each fusion technique for LSS was ranked by rank probabilities.

RESULTS

Totally 29 studies involving 2,379 patients were eligible. For pain, percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) was most likely to be the best technique, followed by minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral interbody fusion (XLIF), and transforaminal lumbar interbody fusion (TLIF). Percutaneous endoscopic posterior lumbar interbody fusion (Endo-PLIF) had the greatest likelihood to be the optimal technique for low back pain, followed sequentially by MIS-TLIF, minimally invasive posterior lumbar interbody fusion (MIS-PLIF), XLIF, Endo-TLIF, TLIF, oblique lumbar interbody fusion (OLIF), posterior lumbar interbody fusion (PLIF), and posterolateral lumbar fusion (PLF). MIS-PLIF was ranked the most effective technique concerning leg pain, followed by Endo-TLIF, MIS-TLIF, TLIF, Endo-PLIF, PLIF, OLIF, PLF, and XLIF. As regards JOA scores, Endo-TLIF had the maximum probability to be the best technique, followed by MIS-TLIF and TLIF. Endo-PLIF had the greatest likelihood to be the optimum technique for complications, followed by TLIF, MIS-TLIF, Endo-TLIF, OLIF, and XLIF.

CONCLUSION

Minimally invasive fusion techniques may be effective in the treatment of LSS, compared with traditional techniques. Minimally invasive techniques were likely non-inferior with regards to postoperative complications.

"Early Efficacy and Safety of Unilateral Biportal Endoscopic Lumbar Interbody Fusion Versus Minimal Invasive in the Treatment of Lumbar Degenerative Diseases"

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

To compare the early clinical efficacy and radiologic outcomes between unilateral biportal endoscopic lumbar interbody fusion (ULIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

SUMMARY OF BACKGROUND DATA

Along with the continuous development of endoscopic technology, the early safety and effectiveness of ULIF technology are still unknown.

MATERIALS AND METHODS

This retrospective study included 61 patients who underwent fusion surgery through ULIF or MIS-TLIF in 2021. Twenty-nine patients underwent ULIF (group A), and 32 underwent MIS-TLIF (group B). Fusion rate, bone graft volume, hidden blood loss (HBL), C-reactive protein level, operative time, Oswestry Disability Index , Visual Analog Scale score, and MacNab criteria were assessed in both groups.

RESULTS

The Visual Analog Scale score for back pain in the early postoperative period was significantly lower in group A than in group B ( P <0.05). All other clinical scores showed improvement, with no significant difference between the 2 groups ( P >0.05). There was no statistically significant difference in postoperative C-reactive protein levels and fusion rates between the 2 groups ( P >0.05). However, HBL was higher and operative time was longer in group A than in group B ( P <0.05). Most importantly, there were no statistically significant differences between groups A and B in fusion rate, length of stay and bone graft volume ( P >0.05). No serious surgical complications occurred in our study.

CONCLUSIONS

ULIF is a new option for lumbar fusion. Despite the drawbacks of longer operation time and higher HBL, ULIF may be a viable alternative to MIS-TLIF as technology advances.

Effect of the preoperative assessment of the anteroposterior diameters of the spinal canal and dural area on the efficacy of oblique lumbar interbody fusion in patients with lumbar spinal stenosis

OBJECTIVE

The purpose of this study was to quantify the degree of lumbar spinal stenosis by assessing the anterior and posterior vertebral canal diameter and dural area, determine the sensitivity of the anterior and posterior spinal canal diameter, dural area and dural occupying rate in predicting the postoperative efficacy of oblique lumbar interbody fusion (OLIF) for patients with single-stage lumbar spinal stenosis, and identify the corresponding indicators suggesting that OLIF surgery should not be performed.

METHODS

In a retrospective analysis of patients who had previously undergone OLIF surgery in our hospital, we included a total of 104 patients with lumbar spinal stenosis who had previously undergone single-stage surgery in our hospital. Three independent observers were employed to measure the anterior and posterior diameter of the spinal canal (AD, mm), dural area (CSA, mm2), the spinal canal area (SCA, mm2), and the ratio of the dural area to the spinal canal area (DM, %) at the disc level with the most severe stenosis on MRI. According to the values of AD and CSA in preoperative MRI, patients were divided into three groups: A, B, and C (Group A: AD > 12 and 100 < CSA ≤ 130, group B: Except A and C, group C: AD ≤ 10 and CSA ≤ 75). Preoperative and postoperative clinical outcome scores (Japanese Orthopaedic Association [JOA] score, VAS score, modified Macnab standard) of 104 patients were statistically.

RESULTS

There were significant differences in the preoperative and postoperative clinical correlation scores among the mild, moderate and severe lumbar spinal stenosis groups. The improvement rate of the post treatment JOA score, the difference between the preoperative and postoperative VAS score, and the modified Macnab standard were compared pairwise. There was no statistical significance in the improvement rate of the post treatment JOA score, the difference between the preoperative and postoperative VAS score, and the modified Macnab standard between Group A and Group B (P = 0.125, P = 0.620, P = 0.803). There were statistically significant differences between Group A and Group C and between Group B and Group C in the improvement rate of the JOA score, the difference in the pre- and postoperative VAS score, and the modified Macnab standard. The anterior and posterior vertebral canal diameter and dural area are sensitive predictors of the postoperative efficacy of OLIF surgery for single-stage lumbar spinal stenosis. Moreover, when the anterior and posterior vertebral canal diameter was less than 6.545 mm and the dural area was less than 34.43 mm2, the postoperative effect of OLIF surgery was poor.

CONCLUSIONS

All the patients with mild, moderate, and severe lumbar spinal stenosis achieved curative effects after OLIF surgery. Patients with mild and moderate lumbar spinal stenosis had better curative effects, and there was no significant difference between them, while patients with severe lumbar spinal stenosis had poor curative effects. Both the anteroposterior diameter of the spinal canal and the dural area of the spinal canal were sensitive in predicting the curative effect of OLIF surgery for single-stage lumbar spinal stenosis. When the anterior and posterior vertebral canal diameter was less than 6.545 mm and the dural area was less than 34.43 mm2, the postoperative effect of OLIF surgery was poor.

Establishing a Standardized Clinical Consensus for Reporting Complications Following Lateral Lumbar Interbody Fusion

Background and Objectives: Mitigating post-operative complications is a key metric of success following interbody fusion. LLIF is associated with a unique complication profile when compared to other approaches, and while numerous studies have attempted to report the incidence of post-operative complications, there is currently no consensus regarding their definitions or reporting structure. The aim of this study was to standardize the classification of complications specific to lateral lumbar interbody fusion (LLIF). Materials and Methods: A search algorithm was employed to identify all the articles that described complications following LLIF. A modified Delphi technique was then used to perform three rounds of consensus among twenty-six anonymized experts across seven countries. Published complications were classified as major, minor, or non-complications using a 60% agreement threshold for consensus. Results: A total of 23 articles were extracted, describing 52 individual complications associated with LLIF. In Round 1, forty-one of the fifty-two events were identified as a complication, while seven were considered to be approach-related occurrences. In Round 2, 36 of the 41 events with complication consensus were classified as major or minor. In Round 3, forty-nine of the fifty-two events were ultimately classified into major or minor complications with consensus, while three events remained without agreement. Vascular injuries, long-term neurologic deficits, and return to the operating room for various etiologies were identified as important consensus complications following LLIF. Non-union did not reach significance and was not classified as a complication. Conclusions: These data provide the first, systematic classification scheme of complications following LLIF. These findings may improve the consistency in the future reporting and analysis of surgical outcomes following LLIF.

Lumbar Interbody Fusion and Osteobiologics for Lumbar Fusion

Lumbar interbody fusion (LIF) is an excellent treatment option for a number of lumbar diseases. LIF can be performed through posterior, transforaminal, anterior, and lateral or oblique approaches. Each technique has its own pearls and pitfalls. Through LIF, segmental stabilization, neural decompression, and deformity correction can be achieved. Minimally invasive surgery has recently gained popularity and each LIF procedure can be performed using minimally invasive techniques to reduce surgery-related complications and improve early postoperative recovery. Despite advances in surgical technology, surgery-related complications after LIF, such as pseudoarthrosis, have not yet been overcome. Although autogenous iliac crest bone graft is the gold standard for spinal fusion, other bone substitutes are available to enhance fusion rate and reduce complications associated with bone harvest. This article reviews the surgical procedures and characteristics of each LIF and the osteobiologics utilized in LIF based on the available evidence.

Surgeon Learning Curve and Clinical Outcomes of Minimally Invasive Anterior Lumbar Interbody Fusion With Posterior Percutaneous Instrumentation

OBJECTIVES

This study reports the learning phase of the minimally invasive anterior lumbar interbody fusion (mini-ALIF) approach with a vascular and orthopaedic spine surgeon team.

METHODS

Adult patients who underwent primary mini-ALIF at the lowest two segments of the lumbar spine (i.e., L4/5, L5/S1) between January 2010 and December 2018 were analyzed.

RESULTS

One hundred twenty-seven patients were included. There was no notable change in total surgical time over the study period. Estimated blood loss markedly decreased until stabilizing at case 30 and slowly declined thereafter. The mean estimated blood loss was 184 mL for L5/S1, 232 mL for L4/L5, and 458 mL for two-level mini-ALIF. There were 20 vascular issues requiring primary repair or packing. Vascular issues declined over time, with a rate of 32% in the first 25 cases and 0% in the last 25. The postoperative complication rate was highest in the first 25 cases (7 of 21 total complications). The odds ratio of vascular injury with body mass index (BMI) > 35 was 4.09 (1.4 to 11.7 confidence interval, P ≤ 0.008). Total surgical time and postoperative complications increased with increasing BMI.

CONCLUSION

Performance of the mini-ALIF approach is associated with a learning curve of 25 to 30 cases before complications begin to decline. BMI > 35 is associated with increased surgical time and complications.

Minimally invasive versus open surgery for degenerative lumbar pathologies:a systematic review and meta-analysis

Introduction

With the increase in life expectancy and consequent aging of the population, degenerative lumbar spine diseases tend to increase its number exponentially. Several treatment options are available to treat degenerative spinal diseases, such as laminectomies, posterior fusions, and interbody fusions, depending on their locations, correction necessities, and surgeon philosophy. With the advance in technology and surgical knowledge, minimally invasive techniques (MIS) arose as a solution to reduce surgical morbidity, while maintaining the same benefits as the traditionally/open surgeries. Several studies investigated the possible advantages of MIS techniques against the traditional open procedures. However, those articles are usually focused only on one technique or on one pathology.

Methods

The electronic databases, including PubMed, Google Scholar, Ovid, and BVS, were systematically reviewed. Only original articles in English or Portuguese were added to the review, the revision was performed following the PRISMA guideline.

Results

Fifty-three studies were included in the meta-analysis. Of the studied outcomes the Length of Stay Odds of complications, Blood Loss, and Surgery costs presented significantly favored MIS approaches, while the Last FUP ODI score, and Surgery Time did not differ among the groups.

Conclusion

Minimally invasive techniques are a remarkably interesting option to traditional open surgeries, as these procedures showed a significant reduction in blood loss, hospitalization time, complications, and surgical costs.

Single-level TLIF Versus LLIF at L4-5: A Comparison of Patient-reported Outcomes and Recovery Ratios

INTRODUCTION

Both transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are suitable for achievement of lumbar arthrodesis. Comparative studies have observed complications and outcomes without stratification by lumbar level. This study aims to assess patient-reported outcome measures (PROMs) and recovery in TLIF and LLIF at L4-5.

METHODS

Patients undergoing primary, elective, single-level, TLIF or LLIF procedures at L4-5 were grouped. Demographics, perioperative characteristics, and postoperative complication rates were collected. PROMs included Patient-Reported Outcome Measurement Information System Physical Function, visual analog scale (VAS) back and leg, Oswestry Disability Index, and 12-Item Short-Form Physical Component Summary, and Mental Component Summary and were collected at preoperative, 6-week, 12-week, 6-month, 1-year, and 2-year time points. Delta values and recovery ratios (RRs) were calculated for all PROMs at all time points. Demographics, perioperative characteristics, and postoperative complications were compared using chi-squared and Student t-test for categorical and continuous variables, respectively. Differences in mean PROMs, delta values, and RR at each time point were evaluated using unpaired Student's t-test.

RESULTS

Three hundred sixty TLIF and 46 LLIF patients were included. Most (54.3%) were men, mean age 56.3 years, and mean body mass index 30.8 kg/m2. Body mass index and insurance significantly differed (P ≤ 0.045, all). TLIF showed significantly greater mean operative time, length of stay, and postoperative narcotic consumption (P < 0.033, all) and greater postoperative nausea/vomiting (P = 0.004). No preoperative PROMs significantly differed. TLIF cohort had significantly greater VAS back at 6 months and VAS leg at 12 weeks and 6 months (P < 0.034, all). No mean delta PROMs or RRs significantly differed.

DISCUSSION

LLIF demonstrated significantly reduced length of stay, postoperative narcotic consumption, and postoperative nausea/vomiting and significantly improved VAS back at 6 months and VAS leg at 12 weeks and 6 months versus TLIF. Although 2-year PROMs and RRs did not significantly differ, our findings may suggest improved midterm follow-up pain scores for LLIF patients.

Clinical Accuracy, Technical Precision, and Workflow of the First in Human Use of an Augmented-Reality Head-Mounted Display Stereotactic Navigation System for Spine Surgery

BACKGROUND

Augmented reality mediated spine surgery is a novel technology for spine navigation. Benchmark cadaveric data have demonstrated high accuracy and precision leading to recent regulatory approval. Absence of respiratory motion in cadaveric studies may positively bias precision and accuracy results and analogous investigations are prudent in live clinical scenarios.

OBJECTIVE

To report a technical note, accuracy, precision analysis of the first in-human deployment of this technology.

METHODS

A 78-yr-old female underwent an L4-S1 decompression, pedicle screw, and rod fixation for degenerative spine disease. Six pedicle screws were inserted via AR-HMD (xvision; Augmedics, Chicago, Illinois) navigation. Intraoperative computed tomography was used for navigation registration as well as implant accuracy and precision assessment. Clinical accuracy was graded per the Gertzbein-Robbins (GS) scale by an independent neuroradiologist. Technical precision was analyzed by comparing 3-dimensional (3D) (x, y, z) virtual implant vs real implant position coordinates and reported as linear (mm) and angular (°) deviation. Present data were compared to benchmark cadaveric data.

RESULTS

Clinical accuracy (per the GS grading scale) was 100%. Technical precision analysis yielded a mean linear deviation of 2.07 mm (95% CI: 1.62-2.52 mm) and angular deviation of 2.41° (95% CI: 1.57-3.25°). In comparison to prior cadaveric data (99.1%, 2.03 ± 0.99 mm, 1.41 ± 0.61°; GS accuracy 3D linear and angular deviation, respectively), the present results were not significantly different (P > .05).

CONCLUSION

The first in human deployment of the single Food and Drug Administration approved AR-HMD stereotactic spine navigation platform demonstrated clinical accuracy and technical precision of inserted hardware comparable to previously acquired cadaveric studies.

The Results of Using a Transforaminal Lumbar Interbody Fusion Cage at the Upper Lumbar Level

Aim

The aim of this study is to apply surgical treatments to upper lumbar disc hernias in order to provide lumbar stability and lumbar lordosis using a transforaminal lumbar interbody fusion (TLIF) cage and to preserve the success rate of surgical results by protecting neural structures without excessive subject tension.

Material and methods

Between 2012 and 2017, 32 patients who had undergone an operation for upper lumbar disc herniation and who had received a transforaminal lumbar interbody fusion cage using a posterior technique were evaluated retrospectively.

Results

The radiological and clinical findings, surgical methods, and results of the patients were evaluated. In our study, 25 (78.1%) of the patients with upper lumbar disc hernias who were evaluated retrospectively were female and seven (21.9%) were male. Their average age was 55.43 years. The average follow-up was 21.75 months. The most common complaints were lower back pain, leg pain, and claudication. In the findings from neurological examinations, a positive result on the femoral stretching test occurred in 30 (93.7%) patients. In the degenerative spinal structure of patients at the L1-2 and L2-3 levels, a transforaminal lumbar interbody fusion was performed via a wide laminectomy with posterior stabilization due to a wide-bottomed disc hernia and stenosis. Only one of the patients with a neurological deficit still had a motor deficit after surgery.

Conclusion

While planning a surgery for upper lumbar disc hernias, the anatomical features of this region and the patients' radiological and neurological findings should be carefully evaluated. If TLIF is performed during upper lumbar region surgery, it may be preferable to perform it using a posterior technique.

A cadaveric precision and accuracy analysis of augmented reality-mediated percutaneous pedicle implant insertion

OBJECTIVE

Augmented reality-mediated spine surgery (ARMSS) is a minimally invasive novel technology that has the potential to increase the efficiency, accuracy, and safety of conventional percutaneous pedicle screw insertion methods. Visual 3D spinal anatomical and 2D navigation images are directly projected onto the operator's retina and superimposed over the surgical field, eliminating field of vision and attention shift to a remote display. The objective of this cadaveric study was to assess the accuracy and precision of percutaneous ARMSS pedicle implant insertion.

METHODS

Instrumentation was placed in 5 cadaveric torsos via ARMSS with the xvision augmented reality head-mounted display (AR-HMD) platform at levels ranging from T5 to S1 for a total of 113 total implants (93 pedicle screws and 20 Jamshidi needles). Postprocedural CT scans were graded by two independent neuroradiologists using the Gertzbein-Robbins scale (grades A-E) for clinical accuracy. Technical precision was calculated using superimposition analysis employing the Medical Image Interaction Toolkit to yield angular trajectory (°) and linear screw tip (mm) deviation from the virtual pedicle screw position compared with the actual pedicle screw position on postprocedural CT imaging.

RESULTS

The overall implant insertion clinical accuracy achieved was 99.1%. Lumbosacral and thoracic clinical accuracies were 100% and 98.2%, respectively. Specifically, among all implants inserted, 112 were noted to be Gertzbein-Robbins grade A or B (99.12%), with only 1 medial Gertzbein-Robbins grade C breach (> 2-mm pedicle breach) in a thoracic pedicle at T9. Precision analysis of the inserted pedicle screws yielded a mean screw tip linear deviation of 1.98 mm (99% CI 1.74-2.22 mm) and a mean angular error of 1.29° (99% CI 1.11°-1.46°) from the projected trajectory. These data compare favorably with data from existing navigation platforms and regulatory precision requirements mandating that linear and angular deviation be less than 3 mm (p < 0.01) and 3° (p < 0.01), respectively.

CONCLUSIONS

Percutaneous ARMSS pedicle implant insertion is a technically feasible, accurate, and highly precise method.

Full Endoscopic Lumbar Transforaminal Interbody Fusion in DDD Lumbar Degenerative Disc Disease: A Latest Technique

BACKGROUND

Lumbar interbody fusion has long been used in the treatment of degenerative disc disease. Lumbar spinal interbody fusion surgery traditionally is an open surgical technique. Although lumbar spinal interbody fusions using endoscopy have been reported, the endoscope was used partially for the interbody fusion. We are reporting a case where lumbar interbody fusion with discectomy was entirely done through direct visualization with the endoscope.

METHODS

We report a case of a 55-year-old woman who underwent the transforaminal percutaneous full-endoscopic lumbar interbody fusion technique (FELTIF) under continuous and direct visualization at the L5-S1 level. To facilitate the interbody fusion, a foraminoplasty with complete resection of the superior articular process (SAP) and a partial pediculectomy of the S1 pedicle was performed. End plate sparing decortication techniques were used under direct video endoscopic visualization. The cage and bone graft insertion occurred through the endoscopic working cannula, thereby protecting the retracted traversing and exiting nerve roots at the surgical level. Posterior supplemental fixation with percutaneous pedicle screws was performed to complete the circumferential fusion.

RESULT

The VAS leg score was reduced to 2 from preoperative score of 7 and the VAS back score reduced 3 from preoperative score of 9. Her neurogenic symptom score improved from 8 before surgery to 1 at the last follow-up. The fusion is assessed by plain radiographs in follow up.

CONCLUSIONS

We concluded that the insertion of an interbody fusion cage device directly through an endoscopic working cannula was technically feasible. Future research should focus on examining the clinical outcomes of this technique.

LEVEL OF EVIDENCE

4.

Trends in lumbar spinal fusion-a literature review

Over the past several decades, there has been an upward trend in the total number of spinal fusion procedures worldwide. Advanced spinal fusion techniques with or without internal fixation, additional innovations in surgical approaches, innovative implants including a wide variety of interbody devices, and new alternatives in bone grafting materials are some reasons for the increasing number of spine fusion procedures. Moreover, the indications for spinal fusion have broadened over time. Initially developed for the treatment of instability and deformity due to tuberculosis, scoliosis, and traumatic injury, spinal fusion surgery has now a wide range of indications like spondylolisthesis, congenital or degenerative deformity, spinal tumors, and pseudarthrosis, with degenerative disorders as the most common indication. This review emphasizes current lumbar fusion techniques and their development in the past decades.

Lumbar Interbody Fusion: Techniques, Pearls and Pitfalls

Lumbar interbody fusion (LIF) is an effective and popular surgical procedure for the management of various spinal pathologies, especially degenerative diseases. Currently, LIF can be performed with posterior, transforaminal, anterior, and lateral approaches by open surgery or minimally invasive surgery (MIS). Each technique has its own advantages and disadvantages. In general, posterior LIF is a well-established procedure with good fusion rates and low complication rates but is limited by the possibility of iatrogenic injury to the neural structures and paraspinal muscles. Transforaminal LIF is frequently performed using an MIS technique and has an advantage of reducing these iatrogenic injuries. Anterior LIF (ALIF) can restore the disk height and sagittal alignment but has inherent approach-related challenges such as visceral and vascular complications. Lateral LIF and oblique LIF are performed using an MIS technique and have shown postoperative outcomes similar to ALIF; however, these approaches carry a risk of injury to psoas, lumbar plexus, and vascular structures. Herein, we provide a detailed description of the surgical procedures of each LIF technique. We shall then consider the pearls and pitfalls, as well as propose surgical indications and contraindications based on the available evidence in the literatures.

Interbody Fusions in the Lumbar Spine: A Review

BACKGROUND

Lumbar interbody fusion is among the most common types of spinal surgery performed. Over time, the term has evolved to encompass a number of different approaches to the intervertebral space, as well as differing implant materials. Questions remain over which approaches and materials are best for achieving fusion and restoring disc height.

QUESTIONS/PURPOSES

We reviewed the literature on the advantages and disadvantages of various methods and devices used to achieve and augment fusion between the disc spaces in the lumbar spine.

METHODS

Using search terms specific to lumbar interbody fusion, we searched PubMed and Google Scholar and identified 4993 articles. We excluded those that did not report clinical outcomes, involved cervical interbody devices, were animal studies, or were not in English. After exclusions, 68 articles were included for review.

RESULTS

Posterior approaches have advantages, such as providing 360° support through a single incision, but can result in retraction injury and do not always restore lordosis or correct deformity. Anterior approaches allow for the largest implants and good correction of deformities but can result in vascular, urinary, psoas muscle, or lumbar plexus injury and may require a second posterior procedure to supplement fixation. Titanium cages produce improved osteointegration and fusion rates but also increase subsidence caused by the stiffness of titanium relative to bone. Polyetheretherketone (PEEK) has an elasticity closer to that of bone and shows less subsidence than titanium cages, but as an inert compound PEEK results in lower fusion rates and greater osteolysis. Combination PEEK-titanium coating has not yet achieved better results. Expandable cages were developed to increase disc height and restore lumbar lordosis, but the data on their effectiveness have been inconclusive. Three-dimensionally (3D)-printed cages have shown promise in biomechanical and animal studies at increasing fusion rates and reducing subsidence, but additive manufacturing options are still in their infancy and require more investigation.

CONCLUSIONS

All of the approaches to spinal fusion have plusses and minuses that must be considered when determining which to use, and newer-technology implants, such as PEEK with titanium coating, expandable, and 3D-printed cages, have tried to improve upon the limitations of existing grafts but require further study.

Predictors of the need for laminectomy after indirect decompression via initial anterior or lateral lumbar interbody fusion

OBJECTIVE

The goal of this study was to evaluate factors that are associated with the need for additional posterior direct decompressive surgery after anterior lumbar interbody fusion (ALIF) or lateral lumbar interbody fusion (LLIF).

METHODS

Eighty-six adult patients who underwent ALIF or LLIF for degenerative spondylolisthesis and foraminal stenosis were enrolled. Patient factors (age, sex, number of surgery levels, and visual analog scale [VAS] score for leg and back pain); procedure-related factors (cage height and lordosis); and radiographic measurements (disc height [DH]; foraminal height [FH], foraminal area [FA], central canal diameter [CCD], and facet joint degeneration [FD]) were analyzed. All patients underwent staged surgery on 2 different days, with the anterior portion first, followed by the posterior portion.

RESULTS

Of 86 patients, 62 underwent posterior decompression and 24 had no posterior decompression. There were no significant differences between groups with regard to age, sex, preoperative VAS score for back pain, cage height, cage angulation, preoperative DH, FH, FA, CCD, and FD (p > 0.05). The group that underwent posterior decompression showed statistically different numbers of treated segments (1.92 vs 1.21, p < 0.01), preoperative VAS leg score (7.9 vs 6.3), symptom duration (14.2 months vs 9.4 months), postoperative DH improvement (61.3% vs 96.2%), postoperative FH improvement (21.5% vs 32.1%), postoperative FA improvement (24.1% vs 36.9%), and cage height minus preoperative DH (5.3 mm vs 7.5 mm) compared with the nondecompression group.

CONCLUSIONS

There appears to be some correlation between the need for posterior decompression and the number of treated segments, VAS leg scores, symptom duration, FH, FA, and difference between the cage height and preoperative DH. In selected patients undergoing staged surgery, indirect decompression without direct decompression may be a reasonable option in treating degenerative spinal conditions.

Distinct fusion intersegmental parameters regarding local sagittal balance provide similar clinical outcomes: a comparative study of minimally invasive versus open transforaminal lumbar interbody fusion

Background

Most contemporary studies suggested that intersegmental parameters including disc height and local lordosis contribute to the sagittal balance of fused lumbar. Although similar clinical outcomes following MIS- and Open-TLIF were reported essentially at the early postoperative time, the comparison of local balance variables after these two different techniques was lack. The radiological differences maybe not relevant to the postoperative efficacy at an earlier post-operation stage. But during the long-term follow-up, the complications with regards to the sagittal imbalance might occur due to the distinct biomechanical properties of fusion level after MIS- and Open-TLIF.

Methods

The patients who underwent a single-level MIS- and Open-TLIF were reviewed retrospectively. The anterior disc height (ADH), posterior disc height (PDH), and segmental lordosis (SL) of the fusion segment were measured using recognition technical fluoroscopy. The mean disc height (MDH) was calculated by (ADH + PDH)/2. The relative DH was normalized by the anterior height of the upper vertebrae. The body mass index (BMI), the pain score of low back and leg visual analogue scale (VAS), Oswestry disability index (ODI), estimated blood loss, and hospital stay length was collected.

Results

A total of 88 patients undergoing a single-level TLIF (MIS and Open) were included. The pre- and post-operative ADH, PDH, MDH, and SL of MIS-TLIF group were 1.57 ± 0.33 cm, 0.79 ± 0.20 cm, 1.18 ± 0.21 cm, 7.36 ± 3.07 and 1.63 ± 0.30 cm, 1.02 ± 0.28 cm, 1.32 ± 0.24 cm, 10.24 ± 4.79 respectively. Whereas, the pre- and post-operative ADH, PDH, MDH, and SL of Open-TLIF group were 1.61 ± 0.40 cm, 0.77 ± 0.21 cm, 1.19 ± 0.24 cm, 9.05 ± 5.48 and 1.81 ± 0.33 cm, 0.98 ± 0.24 cm, 1.39 ± 0.24 cm, 12.34 ± 4,74 respectively. MIS- and Open-TLIF group showed no significant differences in low back VAS, leg VAS, and ODI both in pre-operation and post-operation (P > 0.05). The estimated blood loss and hospital stay length in the MIS-TLIF group were significantly lower than those in the Open-TLIF group (P < 0.05).

Conclusion

MIS- and Open-TLIF provided similar clinical outcomes as the respect of low back VAS, leg VAS, and ODI. MIS-TLIF significantly reduced the blood loss and length of hospital stay though. The intervertebral parameters of DH and SL were both increased significantly, Open-TLIF group presented better sagittal balance in term of ADH and SL variables. The contrast investigation of intersegmental parameters may help the surgeons to figure out the further advantages of MIS-TLIF technique, and then better manage the rehabilitation and prevent the reoperation.

[Comparison of intervertebral height and lordosis of fusion segment between open- and minimally invasive-transforaminal lumbar interbody fusions]

OBJECTIVE

To analyze the restoration of intervertebral height and lordosis of fusion segment after open-transforaminal lumbar interbody fusion (Open-TLIF) and minimally invasive-TLIF (MIS-TLIF).

METHODS

Between January 2013 and February 2016, patients who treated with TLIF due to lumbar degenerative diseases and met the selection criteria were selected as the study objects. Among them, 41 patients were treated with open-TLIF (Open-TLIF group), 34 patients were treated with MIS-TLIF (MIS-TLIF group). There was no significant difference between the two groups ( P>0.05) in gender, age, body mass index, disease type, disease duration, pathological segment, and other general data. The intraoperative bleeding volume, hospital stay, visual analogue scale (VAS) score of waist and leg, and Oswestry disability index (ODI) were recorded before and after operation. The anterior disc height (ADH), posterior disc height (ADH), and segmental lordosis (SL) of fusion segment were measured by X-ray film before and at 6 months after operation. The differences of ADH, PDH, and SL between pre- and post-operation were calculated.

RESULTS

The intraoperative bleeding volume and hospital stay in Open-TLIF group were significantly higher than those in MIS-TLIF group ( t=14.619, P=0.000; t=10.021, P=0.000). All incisions healed by first intention without early complications. All patients were followed up 6-24 months (mean, 12.6 months) in Open-TLIF group and 6-24 months (mean, 11.5 months) in MIS-TLIF group. The preoperative VAS scores of waist and leg and ODI of the two groups significantly improved ( P<0.05). There was no significant difference in VAS scores and ODI between the two groups before operation and at 2 weeks and 6 months after operation ( P>0.05). Imaging examination showed the good intervertebral fusion. There was no significant difference in ADH, PDH, and SL between the two groups before operation and at 6 months after operation ( P>0.05). The differences of ADH, PDH, and SL between the two groups were not significant ( P>0.05). The ADH, PDH, and SL after operation significantly increased in the two groups ( P<0.05).

CONCLUSION

Open-TLIF and MIS-TLIF show similar effectiveness and radiological change in the treatment of single lumbar degenerative diseases and the improved intervertebral height and lordosis, but MIS-TLIF can significantly reduce hospital stay and intraoperative blood loss.

Minimally Invasive Lateral Retropleural and Retroperitoneal Approaches in Patients with Thoracic and Lumbar Osteomyelitis: Description of the Techniques and a Series of 14 Patients

BACKGROUND

The growing interest in minimally invasive approaches to the thoracic and lumbar spine is mostly secondary to the high surgical morbidity and complication rates associated with conventional open approaches. The objective was to report the largest series of patients with thoracic and lumbar vertebral osteomyelitis who underwent multilevel corpectomies using the minimally invasive lateral (MIL) retropleural and retroperitoneal approaches.

METHODS

The surgical techniques of the MIL approaches are illustrated and described in detail. The MIL retropleural approach was performed in 9 patients, MIL retroperitoneal approach in 3 patients, and combined MIL retropleural/retroperitoneal approach in 2 patients with thoracic, lumbar and thoracolumbar vertebral osteomyelitis, respectively.

RESULTS

Multilevel corpectomies were successfully accomplished in all 14 patients using the MIL approaches (11 patients with 2-level corpectomy, 2 patients with 3-level corpectomy, and 1 patient with extension of a 3-level corpectomy to 6 levels). Correction of kyphotic deformity was achieved postoperatively in all 14 patients and remained stable with no proximal junctional kyphosis for a median of 10 months of follow-up on 10 patients; 4 patients were lost to follow-up after discharge from the hospital. Posterior instrumentation was performed in 12 patients to further support the spinal alignment.

CONCLUSIONS

The MIL retropleural and retroperitoneal approaches described in this manuscript are feasible and safe in achieving multilevel corpectomies, anterior column reconstruction, and spinal deformity correction in patients with thoracic, lumbar, and thoracolumbar vertebral osteomyelitis.

Regional variations in acceptance, and utilization of minimally invasive spinal surgery techniques among spine surgeons: results of a global survey

Background

Regional differences in acceptance and utilization of MISST by spine surgeons may have an impact on clinical decision-making and the surgical treatment of common degenerative conditions of the lumbar spine. The purpose of this study was to analyze the acceptance and utilization of various minimally invasive spinal surgery techniques (MISST) by spinal surgeons the world over.

Methods

The authors solicited responses to an online survey sent to spine surgeons by email, and chat groups in social media networks including Facebook, WeChat, WhatsApp, and Linkedin. Surgeons were asked the following questions: (I) Do you think minimally invasive spinal surgery is considered mainstream in your area and practice setting? (II) Do you perform minimally invasive spinal surgery? (III) What type of MIS spinal surgery do you perform? (IV) If you are performing endoscopic spinal decompression surgeries, which approach do you prefer? The responses were cross-tabulated by surgeons' demographic data, and their practice area using the following five global regions: Africa & Middle East, Asia, Europe, North America, and South America. Pearson Chi-Square measures, Kappa statistics, and linear regression analysis of agreement or disagreement were performed by analyzing the distribution of variances using statistical package SPSS Version 25.0.

Results

A total of 586 surgeons accessed the survey. Analyzing the responses of 292 submitted surveys regional differences in opinion amongst spine surgeons showed that the highest percentage of surgeons in Asia (72.8%) and South America (70.2%) thought that MISST was accepted into mainstream spinal surgery in their practice area (P=0.04) versus North America (62.8%), Europe (52.8%), and Africa & Middle East region (50%). The percentage of spine surgeons employing MISST was much higher per region than the rate of surgeons who thought it was mainstream: Asia (96.7%), Europe (88.9%), South America (88.9%), and Africa & Middle East (87.5%). Surgeons in North America reported the lowest rate of MISST implementation globally (P<0.000). Spinal endoscopy (59.9%) is currently the most commonly employed MISST globally followed by mini-open approaches (55.1%), and tubular retractor systems (41.8%). The most preferred endoscopic approach to the spine is the transforaminal technique (56.2%) followed by interlaminar (41.8%), full endoscopic (35.3%), and over the top MISST (13.7%).

Conclusions

The rate of implementation of MISST into day-to-day clinical practice reported by spine surgeons was universally higher than the perceived acceptance rates of MISST into the mainstream by their peers in their practice area. The survey suggests that endoscopic spinal surgery is now the most commonly performed MISST.

Impact of lumbar interbody fusion surgery on postoperative outcomes in patients with recurrent lumbar disc herniation: Analysis of the US national inpatient sample

Little information is available on associations between different lumbar interbody fusion (LIF) surgeries and postoperative outcomes. The present study aims to comprehensively investigate whether different LIF techniques are associated with postoperative outcomes such as complications and length of hospital stay. The United States Nationwide Inpatient Sample (NIS) was searched for patients diagnosed with recurrent lumbar disc herniation who underwent lumbar interbody fusion (LIF) surgeries between 2005 and 2014. Patients were categorized based on LIF approaches: anterior lumbar interbody fusion (ALIF); lateral lumbar interbody fusion (LLIF); or posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF). A total of 2625 patients were included in this study. After adjusting for age, severity of illness, and comorbidities, patients who received LLIF and PLIF/TLIF approaches had significantly shorter hospital stays than those receiving ALIF (LLIF vs. ALIF, β = -0.64; PLIF/TLIF vs. ALIF, β = -0.40). In addition, patients who received LLIF and PLIF/TLIF approaches had significantly lower risk of digestive system complications compared to those receiving ALIF (LLIF vs. ALIF, aOR = 0.25; PLIF/TLIF vs. ALIF, aOR = 0.18). In conclusion, in patients with recurrent lumbar disc herniation, LLIF and PLIF/TLIF approaches are associated with shorter hospital stays and lower risk of digestive system complications than ALIF. However, LIF approaches do not correlate significantly with the risk of postoperative bleeding or nervous system complications.

Complications Associated With Minimally Invasive Anterior to the Psoas (ATP) Fusion of the Lumbosacral Spine

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To analyze complications associated with minimally invasive anterolateral retroperitoneal antepsoas lumbosacral fusion (MIS-ATP).

SUMMARY OF BACKGROUND DATA

MIS-ATP provides anterolateral access to the lumbar spine allowing for safe anterior lumbar interbody fusions between T12-S1. Anecdotally, many surgeons believe that ATP approach is not feasible at L5-S1 level, predisposing to catastrophic vascular injuries. This approach may help overcome limitations associated with conventional straight anterior lumbar interbody fusions, MIS lateral lumbar interbody fusion, and oblique lateral interbody fusion.

METHODS

A detailed retrospective chart review of patients who had underwent MIS-ATP approach for lumbar fusion between T12-S1 was performed. Available electronic data from surgeries performed between January 2008 and March 2017 was carefully screened for surgical patients treated for spondylolisthesis, spondylosis, stenosis, sagittal, and/or coronal deformity. Detailed review of electronic medical records including operative notes, progress notes, discharge summaries, laboratory results, imaging reports, and clinic visit notes performed by a single independent reviewer not involved in patient care for documented complications. A complication is defined as any adverse event related to the index spine procedure for which patient required specific intervention or treatment.

RESULTS

Nine hundred forty patients with a total of 2429 interbody fusion levels performed via MIS-ATP were identified during the study period. Sixty-seven patients (7.2%) sustained one or more complications during the perioperative period, of which 25.5% were surgical and 74.5% were medical. Overall, 78 (8.2%) surgical complications pertaining to the index procedure were noted during a postoperative period of 1 year from the date of surgery. No major vascular or direct visceral injuries were encountered.

CONCLUSIONS

MIS-ATP approach provides a safe access to anterolateral interbody fusions between T12-S1. The ATP approach is performed by the spine surgeon, does not require neuromonitoring, and warrants minimal to no psoas muscle retraction resulting in significantly reduced postoperative thigh pain and rare neurologic injuries. Additionally, the direct and clear visualization of the retroperitoneal vasculature provided by the ATP approach minimizes the risk of inadvertent vascular injury.

LEVEL OF EVIDENCE

4.

Predictors of Prolonged Length of Stay After Lumbar Interbody Fusion: A Multicenter Study

STUDY DESIGN

Retrospective analysis of a prospectively database.

OBJECTIVES

To identify factors associated with prolonged length of stay (LOS) in posterior /transforaminal lumbar interbody fusion (PLIF/TLIF).

METHODS

The subjects were patients who underwent PLIF/TLIF at 10 facilities from 2012 to 2014. A total of 1168 such patients with a mean age of 65.9 ± 12.5 years (range 18-87 years) were identified in the database. Operations were PLIF (n = 675), TLIF (n = 443), minimally invasive surgery (MIS)-PLIF (n = 22), and MIS-TLIF (n = 32). Age, gender, body mass index, ambulatory status, comorbidities, perioperative American Society of Anesthesiologists (ASA) grade, operative factors, and complications were examined. LOS was defined as the number of calendar days from the operation to hospital discharge. LOS was categorized as normal (<75th percentile) or prolonged (≥75th percentile).

RESULTS

The average LOS was 20.8 ± 9.8 days (range 7-77 days). There was a significant correlation between LOS and age (P < .05). Reoperation during hospitalization was performed in 20 cases for surgical site infection (n = 12), epidural hematoma (n = 5), and screw misplacement (n = 3). In multivariate analysis, prolonged LOS was associated with preoperative variables of age ≥70 years (odds ratio [OR] 1.87, 95% CI 1.38-2.54), and ASA class ≥III (OR 1.52, 95% CI 1.04-2.25); surgical variables of open procedures (OR 5.84, 95% CI 1.74-19.63), fused levels ≥3 (OR 5.17, 95% CI 3.17-8.43), operative time ≥300 minutes (OR 1.88, 95% CI 1.15-3.07), and estimated blood loss ≥500 mL (OR 1.71, 95% 1.07-2.75).

CONCLUSIONS

The factors identified in this study should help with obtaining informed consent, surgical planning and complication prevention to reduce health care costs associated with prolonged LOS.

The Effect of Alendronate on Subsidence After Lateral Transpsoas Interbody Fusion: A Preliminary Report

Background

Success after lateral transpsoas interbody fusion (LLIF) partially depends on avoidance of subsidence to maintain spinal alignment, disc space height, and indirect neural decompression. Techniques for preventing subsidence have focused largely on surgical and biomechanical properties of spinal reconstruction; however, medical management may also affect subsidence rates as well. The purpose of this study is to examine the effect of alendronate on minimally invasive LLIF patients with regard to radiographic and catastrophic subsidence.

Methods

We followed 26 patients who had LLIF at the L4-5 level (13 on alendronate, 13 control) and 22 patients at the L3-4 level (10 on alendronate, 12 control). Radiographs were reviewed to obtain measurements of subsidence at the 4 corners of the cage at 3 follow-up time points (2-3, 5-8, and 10-12 months). A Tobit mixed model was used to confirm the results.

Results

We found no relationship between alendronate and subsidence for L3-4 fusion. At L4-5 we observed increased subsidence in the control group compared to the alendronate group (difference = 0.07 cm, 95% confidence interval [CI]: -0.01, 0.16, P = .08). There was a decrease in subsidence noted for the alendronate group for each time period (differences: 2-3: -0.06 cm, 95% CI: -0.28, 0.15], P = .27; 5-8: -0.14 cm, 95% CI: -0.36, .08, P = .10; 10-12: -0.21 cm, 95% CI: -0.48, .04, P = .05).

Conclusions

A clear reduction in subsidence was found with the use of postoperative alendronate in patients undergoing L4-5 LLIF. Alendronate had a significant decrease in subsidence at L4-5 after 10-12 months as compared to the control group. Additionally, no patients treated with alendronate had catastrophic subsidence. These data suggest the need for further study of alendronate in the prevention of subsidence after LLIF.

Level of Evidence

3.

The use of robotics in minimally invasive spine surgery

The field of spine surgery has changed significantly over the past few decades as once technological fantasy has become reality. The advent of stereotaxis, intra-operative navigation, endoscopy, and percutaneous instrumentation have altered the landscape of spine surgery. The concept of minimally invasive spine (MIS) surgery has blossomed over the past ten years and now robot-assisted spine surgery is being championed by some as another potential paradigm altering technological advancement. The application of robotics in other surgical specialties has been shown to be a safe and feasible alternative to the traditional, open approach. In 2004 the Mazor Spine Assist robot was approved by FDA to assist with placement of pedicle screws and since then, more advanced robots with promising clinical outcomes have been introduced. Currently, robotic platforms are limited to pedicle screw placement. However, there are centers investigating the role of robotics in decompression, dural closure, and pre-planned osteotomies. Robot-assisted spine surgery has been shown to increase the accuracy of pedicle screw placement and decrease radiation exposure to surgeons. However, modern robotic technology also has certain disadvantages including a high introductory cost, steep learning curve, and inherent technological glitches. Currently, robotic spine surgery is in its infancy and most of the objective evidence available regarding its benefits draws from the use of robots in a shared-control model to assist with the placement of pedicle screws. As artificial intelligence software and feedback sensor design become more sophisticated, robots could facilitate other, more complex surgical tasks such as bony decompression or dural closure. The accuracy and precision afforded by the current robots available for use in spinal surgery potentially allow for even less tissue destructive and more meticulous MIS surgery. This article aims to provide a contemporary review of the use of robotics in MIS surgery.

A randomized controlled trial with ≥5 years of follow-up comparing minimally invasive and open transforaminal lumbar interbody fusion in disc herniation at single level

Minimally invasive transforaminal lumbar interbody fusion (m-TLIF) using transpedicular screws has various advantages over classical open (c-) TLIF. Up to date, comparative analyses of the TLIF procedures were following patients for <5 years. The objective of the present study was to compare the clinical effectiveness and complications of m- and c-TLIF in patients with single-level disc herniation with ≥5 years follow-up. Between June 2008 to July 2010, 91 patients with single-level lumbar degeneration were recruited and were randomly divided into two groups: m-TLIF and c-TLIF. The analyzed outcome measurements included: Surgery duration, intraoperative blood loss, X-ray exposure time, T2 relaxation time in magnetic resonance imaging (MRI), visual analogue scale (VAS) scores, Japanese orthopedic association (JOA) scores, fusion rate and complications during follow-up. No significant differences between m- and c-TLIF were observed with respect to surgery duration (P=0.077), volume of blood loss (P=0.115), complications and the need for an additional surgery (P=0.632). Significant differences between the groups were observed for X-ray exposure time (P<0.001) and MRI T2 relaxation times at 3 months post-surgery (P<0.001). At day 7 post surgery, recorded VAS and JOA scores were significantly improved in the m-TLIF compared with the c-TLIF group and non-significant differences between the groups were observed at >1 month follow-up. m-TLIF was a safe and effective tool in treating single-level lumbar disc herniation. However, careful attention to the surgical technique and precise anatomical knowledge were required. Further studies and refinement of the surgical techniques are necessary prior to treating multiple or more extensive lesions using the m-TLIF method.

CT-based Morphometric Analysis of Approach of Percutaneous Transforaminal Endoscopic Lumbar Interbody Fusion

OBJECTIVES

A radiographic study was designed to measure the relationship of the exiting nerve root and its surroundings to the corresponding intervertebral disc for percutaneous transforaminal endoscopic lumbar interbody fusion to better understand the regional anatomy and to improve clinical applications.

METHODS

A retrospective study from January 2017 to October 2017 was conducted at Tianjin Hospital. CT images were obtained from patients presenting low back pain (110 patients), and analysis was performed bilaterally from L2-3 to L5 S1 . In the rotating coronal plane we analyzed: the nerve root-dural sac distance at the superior and inferior margins of the disc (Js, Ji); the nerve root-pedicle distance at the medial, middle, and lateral borders of the pedicle (Pa, Pb, Pc); the pedicle width (W); and the safe working zone, defined as a trapezoid bounded by the inferior pedicle and the exiting nerve root (S). In the transverse plane, the nerve root-articular process and the shortest distance for the nerve root-articular process joint surface were analyzed at the superior and inferior margins of the disc (Gs, Gi), respectively. The groups were analyzed using ANOVA, and paired t-tests were used to compare the left and right sides.

RESULTS

From L2-3 to L5 S1 , the distance of the nerve root to the dural sac was larger at the inferior margin of the disc. From L2-3 to L5 S1 , each segment of the vertebral nerve root-pedicle distance gradually decreased from medial to lateral. From L2-3 to L5 S1 , the distance from the exiting nerve root to the middle and lateral margins of the pedicle gradually decreased, with L5 S1 being the minimum. Some significant differences were observed between the left and right sides for L4-5 and L5 S1 . The pedicle width of the vertebral body and the mean area for the safe working zone gradually increased from L2-3 to L5 S1 . In the axial plane, the shortest distance between the nerve root and articular process joint surface at the inferior margin of the disc was greater than the distance for the nerve root to the articular process at the superior margin of the disc from L2-3 to L5 S1 . There were no significant differences between the two sides.

CONCLUSIONS

It is more difficult to implant a cage with a width of 10 mm above the L3-4 level. By removing part of the superior articular process, the safe working area can be expanded, and damage to the nerve or other structures can be avoided when implanting a cage.

Microscopic Anterior Neural Decompression Combined with Oblique Lumbar Interbody Fusion-A Technical Note

BACKGROUND

Minimally invasive oblique lumbar interbody fusion (OLIF) techniques generally rely on deformity correction to achieve indirect neural decompression. However, indirect neural decompression will not always be sufficient. Thus, a second procedure, such as posterior direct decompression, will be added for full decompression, increasing the surgical morbidity and healthcare costs. We have described a technique of direct anterior microscopic neural decompression combined with OLIF.

METHODS

We report our surgical technique of anterior lumbar neural microscopic decompression with OLIF with patients in the lateral position. We also report the cases of 3 patients treated from March 2018 to June 2018.

RESULTS

Three patients underwent anterior microscopic neural decompression combined with OLIF in the lateral position. All 3 patients achieved clinically and radiologically significant neural decompression and deformity correction. No perioperative complications developed.

CONCLUSION

Direct anterior microscopic neural decompression is feasible and safe in selected patients undergoing OLIF.

Minimally Invasive Far Lateral Lumbar Interbody Fusion: A Prospective Cohort Study

STUDY DESIGN

Prospective cohort study.

OBJECTIVES

To assess rate and degree of interbody bone fusion and evolution in Oswestry Disability index (ODI) and visual analog scale (VAS) of pain after minimally invasive far lateral lumbar interbody fusion.

METHODS

Twenty-three patients with single-level lumbar instability or degenerative disc were treated by this method and prospectively included. VAS of pain and ODI were evaluated preoperatively and at last follow-up. Computed tomography scan was performed 6 months after surgery to assess interbody fusion.

RESULTS

Between preoperative and 2 years postoperative follow-up, mean VAS decreased by 2.4 points (P < .001); mean ODI improved by 21.8% (P < .001). Computed tomography scan showed fusion in all patients but one. No severe complications were observed.

CONCLUSIONS

Minimally invasive far lateral lumbar interbody fusion resulted in satisfactory clinical and radiological results.

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.

Comparison of lateral lumbar interbody fusion (LLIF) with open versus percutaneous screw fixation for adult degenerative scoliosis

Study design

Retrospective Review.

Objectives

Compare clinical outcomes and radiographic correction of adult degenerative scoliosis (ADS) patients treated with lateral lumbar interbody fusion (LLIF), combined either with percutaneous (no laminectomy) versus open laminectomy/pedicle screw instrumentation.

Methods

Twenty-two ADS patients undergoing combined LLIF and posterior instrumentation were divided into two groups: thirteen patients underwent LLIF with open laminectomy and posterior pedicle instrumentation (Group-1, six revision); nine patients underwent LLIF with percutaneous pedicle instrumentation (no decompression) (Group-2). Radiographs, CT/MRI, peri-operative complications, VAS, SF-12, and ODI were measured.

Results

Average follow up was 22 months. In Group-1 and Group-2, respectively: Mean coronal Cobb angle corrected 12.6° and 5.8°; Mean regional lumbar lordosis improved 11.1° and 3.8°; Pelvic incidence minus lumbar lordosis mismatch corrected to within +/-9° in 46% and 0% of patients; Mean VAS improved from 5.4 to 2.8 and 6.3 to 1; Mean ODI improved 19% and 22%. Improvements were found in SF-12 PCS and MCS scores.

Conclusions

Both open and percutaneous posterior techniques following LLIF significantly improved clinical outcomes. Open procedures resulted in significantly better radiographic improvements but also higher complication rates. LLIF with percutaneous posterior fixation, without decompression, should be considered part of the algorithm in select ADS patients with remaining compensatory mechanisms and understanding that greater degrees of correction may require an open, more extensive approach.

Transforaminal Lumbar Interbody Fusion: Traditional Open Versus Minimally Invasive Techniques

Recently, minimally invasive spine arthrodesis has gained popularity among spine surgeons. Minimally invasive techniques have advantages and disadvantages compared with traditional open techniques. Comparisons between short-term outcomes of minimally invasive transforaminal interbody fusion and open transforaminal interbody fusion in terms of estimated blood loss, postoperative pain, and hospital length of stay have been well documented and generally favor the minimally invasive technique. However, the advantages of minimally invasive transforaminal interbody fusion must be evaluated in the context of long-term results, such as patient-reported outcomes and the success of arthrodesis. Because the literature is equivocal in identifying the superior technique for successful long-term outcomes, more study is needed. Patient safety, the risk of complications, and the cost of these techniques also must be considered.

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.].

The Top 50 Articles on Minimally Invasive Spine Surgery

STUDY DESIGN

Bibliometric study of current literature.

OBJECTIVE

To catalog the most important minimally invasive spine (MIS) surgery articles using the amount of citations as a marker of relevance.

SUMMARY OF BACKGROUND DATA

MIS surgery is a relatively new tool used by spinal surgeons. There is a dynamic and evolving field of research related to MIS techniques, clinical outcomes, and basic science research. To date, there is no comprehensive review of the most cited articles related to MIS surgery.

METHODS

A systematic search was performed over three widely used literature databases: Web of Science, Scopus, and Google Scholar. There were four searches performed using the terms "minimally invasive spine surgery," "endoscopic spine surgery," "percutaneous spinal surgery," and "lateral interbody surgery." The amount of citations included was averaged amongst the three databases to rank each article. The query of the three databases was performed in November 2015.

RESULTS

Fifty articles were selected based upon the amount of citations each averaged amongst the three databases. The most cited article was titled "Extreme Lateral Interbody Fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion" by Ozgur et al and was credited with 447, 239, and 279 citations in Google Scholar, Web of Science, and Scopus, respectively. Citations ranged from 27 to 239 for Web of Science, 60 to 279 for Scopus, and 104 to 462 for Google Scholar. There was a large variety of articles written spanning over 14 different topics with the majority dealing with clinical outcomes related to MIS surgery.

CONCLUSION

The majority of the most cited articles were level III and level IV studies. This is likely due to the relatively recent nature of technological advances in the field. Furthermore level I and level II studies are required in MIS surgery in the years ahead.

LEVEL OF EVIDENCE

5.

Does MIS Surgery Allow for Shorter Constructs in the Surgical Treatment of Adult Spinal Deformity?

BACKGROUND: The length of construct can potentially influence perioperative risks in adult spinal deformity (ASD) surgery. A head-to-head comparison between open and minimally invasive surgery (MIS) techniques for treatment of ASD has yet to be performed.

OBJECTIVE: To examine the impact of MIS approaches on construct length and clinical outcomes in comparison to traditional open approaches when treating similar ASD profiles.

METHODS: Two multicenter databases for ASD, 1 involving MIS procedures and the other open procedures, were propensity matched for clinical and radiographic parameters in this observational study. Inclusion criteria were ASD and minimum 2-year follow-up. Independent t-test and chi-square test were used to evaluate and compare outcomes.

RESULTS: A total of 1215 patients were identified, with 84 patients matched in each group. Statistical significance was found for mean levels fused (4.8 for circumferential MIS [cMIS] and 10.1 for open), mean interbody fusion levels (3.6 cMIS and 2.4 open), blood loss (estimated blood loss 488 mL cMIS and 1762 mL open), and hospital length of stay (6.7 days cMIS and 9.7 days open). There was no significant difference in preoperative radiographic parameters or postoperative clinical outcomes (Owestry Disability Index and visual analog scale) between groups. There was a significant difference in postoperative lumbar lordosis (43.3° cMIS and 49.8° open) and pelvic incidence-lumbar lordosis correction (10.6° cMIS and 5.2° open) in the open group. There was no significant difference in reoperation rate between the 2 groups.

CONCLUSION: MIS techniques for ASD may reduce construct length, reoperation rates, blood loss, and length of stay without affecting clinical and radiographic outcomes when compared to a similar group of patients treated with open techniques.

Bone Morphogenic Protein Is a Viable Adjunct for Fusion in Minimally Invasive Transforaminal Lumbar Interbody Fusion

Study Design

Comparison of prospectively collected data of patients undergoing minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF) with and without recombinant human bone morphogenic protein 2 (BMP).

Purpose

To compare the clinical, radiological outcome and complications of patients undergoing MIS-TLIF with and without BMP.

Overview of Literature

BMP is an effective fusion enhancer with potential complications. Direct comparison of MIS-TLIF with and without BMP is limited to retrospective studies with short follow-up.

Methods

From June 2005 to February 2011, consecutive cases of MIS-TLIF performed by a single surgeon were included. North American Spine Society (NASS) score, Oswestry disability index (ODI), Short Form-36 (SF-36), and visual analogue score (VAS) were assessed preoperatively and at 6 and 24 months postoperatively. Fusion rates and complications were noted.

Results

The 252 cases comprised 104 non-BMP and 148 BMP cases. The BMP group was significantly older (mean age, 60.2 vs. 53.9; p<0.01). Preoperative scores were similar. Immediate postoperative morphine usage was significantly lower in the BMP group (12.4 mg vs. 20.1 mg, p<0.01). At 6 months, the BMP group had lower VAS back and leg pain scores (p<0.01). At 2 years, the BMP group had better leg pain scores (p<0.01), ODI (15.4 vs. 20.3, p=0.04) and NASS scores (8.8 vs. 15.8, p<0.01). Both groups showed significant clinical improvement compared to their preoperative levels. The BMP group attained a significantly higher rate of fusion at 6 months follow-up (88.4% vs. 76.8%, p=0.016) with no difference at 2 years. The non-BMP and BMP group had 12 (11.5%) and 9 (6.1%) complications and 5 (4.8%) and 2 (1.4%) reoperations, respectively.

Conclusions

The use of BMP to augment fusion in MIS-TLIF is an acceptable alternative that has potential benefits of less pain in early and intermediate postoperative follow-up.