Extreme lateral interbody fusion for unilateral symptomatic vertical foraminal stenosis

Limited Intervention in Adult Scoliosis-A Systematic Review

BACKGROUND/OBJECTIVES

Adult scoliosis is traditionally treated with long-segment fusion, which provides strong radiographic correction and significant improvements in health-related quality of life but comes at a high morbidity cost. This systematic review seeks to examine the literature behind limited interventions in adult scoliosis patients and examine the best approaches to treatment.

METHODS

This is a MEDLINE- and PubMed-based literature search that ultimately included 49 articles with a total of 21,836 subjects.

RESULTS

Our search found that long-segment interventions had strong radiographic corrections but also resulted in high perioperative morbidity. Limited interventions were best suited to patients with compensated deformity, with decompression best for neurologic symptoms and fusion needed to treat neurological symptoms secondary to up-down stenosis and to provide stability across unstable segments. Decompression can consist of discectomy, laminotomy, and/or foraminotomy, all of which are shown to provide symptomatic relief of neurologic pain. Short-segment fusion has been shown to provide improvements in patient outcomes, albeit with higher rates of adjacent segment disease and concerns for correctional loss. Interbody devices can provide decompression without posterior element manipulation. Future directions include short-segment fusion in uncompensated deformity and dynamic stabilization constructs.

CONCLUSIONS

Limited interventions can provide symptomatic relief to adult spine deformity patients, with indications mostly in patients with balanced deformities and neurological pain.

Advantages of Revision Transforaminal Full-Endoscopic Spine Surgery in Patients who have Previously Undergone Posterior Spine Surgery

BACKGROUND

 Revision lumbar spine surgery via a posterior approach is more challenging than primary surgery because of epidural or perineural scar tissue. It demands more extensive removal of the posterior structures to confirm intact bony landmarks and could cause iatrogenic instability; therefore, fusion surgery is often added. However, adjacent segment disease after fusion surgery could be a problem, and further exposure of the posterior muscles could result in multiple operated back syndrome. To address these problems, we now perform transforaminal full-endoscopic spine surgery (TF-FES) as revision surgery in patients who have previously undergone posterior lumbar surgery. There have been several reports on the advantages of TF-FES, which include feasibility of local anesthesia, minimal invasiveness to posterior structures, and less scar tissue with fewer adhesions. In this study, we aim to assess the clinical outcomes of revision TF-FES and its advantages.

METHODS

 We evaluated 48 consecutive patients with a history of posterior lumbar spine surgery who underwent revision TF-FES (at 60 levels) under local anesthesia. Intraoperative blood loss, operating time, and complication rate were evaluated. Postoperative outcomes were assessed using the modified Macnab criteria and visual analog scale (VAS) scores for leg pain, back pain, and leg numbness. We also compared the outcome of revision FES with that of primary FES.

RESULTS

 Mean operating time was 70.5 ± 14.4 (52-106) minutes. Blood loss was unmeasurable. The clinical outcomes were rated as excellent at 16 levels (26.7%), good at 28 (46.7%), fair at 10 (16.7%), and poor at 6 (10.0%). The mean preoperative VAS score was 6.0 ± 2.6 for back pain, 6.8 ± 2.4 for leg pain, and 6.3 ± 2.8 for leg numbness. At the final follow-up, the mean postoperative VAS scores for leg pain, back pain, and leg numbness were 4.3 ± 2.5, 3.8 ± 2.6, and 4.6 ± 3.2, respectively. VAS scores for all three parameters were significantly improved (p < 0.05). There was no significant difference in operating time, intraoperative blood loss, or the complication rate between revision FES and primary FES.

CONCLUSIONS

 Clinical outcomes of revision TF-FES in patients with a history of posterior lumbar spine surgery were acceptable (excellent and good in 73.4% of cases). TF-FES can preserve the posterior structures and avoid scar tissue and adhesions. Therefore, TF-FES could be an effective procedure for patients who have previously undergone posterior lumbar spine surgery.

Clinical outcomes, MRI evaluation and predictive factors of indirect decompression with lateral transpsoas approach for lumbar interbody fusion: a multicenter experience

Introduction

Evaluating the effects of indirect decompression obtained through lateral lumbar interbody fusion (LLIF) by clinical improvements and radiological parameters on MRI scans. Identifying predictors of better decompression and clinical outcome.

Materials and methods

From 2016 to 2019, patients who underwent single- or double-level indirect decompression LLIF were consecutively reviewed. Radiological signs of indirect decompression were evaluated in preoperative and follow-up MRI studies and were subsequently correlated to clinical data, expressed as axial/radicular pain (VAS back/leg), index of disability (Oswestry Disability Index) and clinical severity of lumbar stenosis (Swiss Spinal Stenosis Questionnaire).

Results

72 patients were enrolled. The mean follow-up was 24 months. Differences in vertebral canal area (p &lt; 0.001), height of the foramina (p &lt; 0.001), thickness of the yellow ligament (p = 0.001) and anterior height of the interbody space (p = 0.02) were observed. Older age (p = 0.042), presence of spondylolisthesis (p = 0.042), presence of intra-articular facet effusion (p = 0.003) and posterior height of the implanted cage (p = 0.020) positively affected the increase of the canal area. Change in root canal area (p &lt; 0.001), height of the implanted cage (p = 0.020) and younger age (p = 0.035) were predictive factors of root pain relief, while increased vertebral canal area (p = 0.020) and height of the interbody fusion cage (p = 0.023) positively affected the severity of clinical stenosis.

Conclusions

LLIF indirect decompression showed both clinical and radiological improvements. Presence and degree of spondylolisthesis, presence of intra-articular facet effusion, age of the patient and height of the cage were predictive factors of major clinical improvements.

L4/5 accessibility for extreme lateral interbody fusion (XLIF): a radiological study

Introduction

Potential advantages of the Extreme Lateral Interbody Fusion (XLIF) approach are smaller incisions, preserving anterior and posterior longitudinal ligaments, lower blood loss, shorter operative time, avoiding vascular and visceral complications, and shorter length of stay. We hypothesize that not every patient can be safely treated at the L4/5 level using the XLIF approach. The objective of this study was to radiographically (CT-scan) evaluate the accessibility of the L4/5 level using a lateral approach, considering defined safe working zones and taking into account the anatomy of the superior iliac crest.

Methods

Hundred CT examinations of 34 female and 66 male patients were retrospectively evaluated. Disc height, lower vertebral endplate (sagittal and transversal), and psoas muscle diameter were quantified. Accessibility to intervertebral space L4/5 was investigated by simulating instrumentation in the transverse and sagittal planes using defined safe zones.

Results

The endplate L5 in the frontal plane considering defined safe zones in the sagittal and transverse plane (Zone IV) could be reached in 85 patients from the right and in 83 from the left side. Through psoas split, the safe zone could be reached through psoas zone II in 82 patients from the right and 91 patients from the left side. Access through psoas zone III could be performed in 28 patients from the right and 32 patients from the left side. Safe access and sufficient instrumentation of L4/5 through an extreme lateral approach could be performed in 76 patients of patients from the right and 70 patients from the left side.

Conclusion

XLIF is not possible and safe in every patient at the L4/5 level. The angle of access for instrumentation, access of the intervertebral disc space, and accessibility of the safe zone should be taken into account. Preoperative imaging planning is important to identify patients who are not suitable for this procedure.

Analysis of rotational deformity correction by lateral lumbar interbody fusion with two-staged anterior-posterior combined corrective fusion surgery for adult degenerative kyphoscoliosis

The present study is retrospective analysis of consecutively collected data. Lateral lumber interbody fusion (LLIF) is widely used in cases of adult spinal deformities. However, the corrective effects of LLIF cage insertion on the vertebral rotation deformity in the axial plane and the individual effects of LLIF and direct vertebral rotation (DVR) on rotational correction are unclear. To individually examine the corrective effects of LLIF and posterior corrective fusion surgery with direct DVR on vertebral rotation deformities in adult degenerative kyphoscoliosis. We analyzed 21 patients (5 males and 16 females) who underwent two-staged anterior-posterior combined corrective fusion surgery for adult degenerative kyphoscoliosis. Surgical time, blood loss, facet joint osteoarthritis (OA) grade, disc degeneration, cage height, vertebral rotational angle, and various X-ray parameters were investigated as evaluation items. The X-ray parameters showed significant postoperative improvements. The mean vertebral rotation angle was 6.4° ± 5.2° preoperatively, 3.5° ± 3.3° after LLIF (P = .014, vs preoperative), and 1.6° ± 1.7° after posterior corrective fusion surgery with DVR (P = .011, vs preoperative). Correlation analysis between the vertebral rotation angle and various measured values revealed that the vertebral rotation angle after LLIF was correlated with the cage height (r = -0.46, P = .032). The vertebral rotation angle after DVR was correlated with the facet joint OA grade (r = -0.49, P = .018) and the wedge angle after posterior corrective fusion surgery with DVR (R = 0.57, P = .006). We conclude that the effects of rotational deformity correction with LLIF cage insertion and additional posterior corrective fixation with DVR can be useful for correcting vertebral rotation deformities.

Effects of osteoporosis on the biomechanics of various supplemental fixations co-applied with oblique lumbar interbody fusion (OLIF): a finite element analysis

Background

Oblique lumbar interbody fusion (OLIF) is an important surgical modality for the treatment of degenerative lumbar spine disease. Various supplemental fixations can be co-applied with OLIF, increasing OLIF stability and reducing complications. However, it is unclear whether osteoporosis affects the success of supplemental fixations; therefore, this study analyzed the effects of osteoporosis on various supplemental fixations co-applied with OLIF.

Methods

We developed and validated an L3-S1 finite element (FE) model; we assigned different material properties to each component and established models of the osteoporotic and normal bone lumbar spine. We explored the outcomes of OLIF combined with each of five supplemental fixations: standalone OLIF; OLIF with lateral plate fixation (OLIF + LPF); OLIF with translaminar facet joint fixation and unilateral pedicle screw fixation (OLIF + TFJF + UPSF); OLIF with unilateral pedicle screw fixation (OLIF + UPSF); and OLIF with bilateral pedicle screw fixation (OLIF + BPSF). Under the various working conditions, we calculated the ranges of motion (ROMs) of the normal bone and osteoporosis models, the maximum Mises stresses of the fixation instruments (MMSFIs), and the average Mises stresses on cancellous bone (AMSCBs).

Results

Compared with the normal bone OLIF model, no demonstrable change in any segmental ROM was apparent. The MMSFIs increased in all five osteoporotic OLIF models. In the OLIF + TFJF + UPSF model, the MMSFIs increased sharply in forward flexion and extension. The stress changes of the OLIF + UPSF, OLIF + BPSF, and OLIF + TFJF + UPSF models were similar; all stresses trended upward. The AMSCBs decreased in all five osteoporotic OLIF models during flexion, extension, lateral bending, and axial rotation. The average stress change of cancellous bone was most obvious under extension. The AMSCBs of the five OLIF models decreased by 14%, 23.44%, 21.97%, 40.56%, and 22.44% respectively.

Conclusions

For some supplemental fixations, the AMSCBs were all reduced and the MMSFIs were all increased in the osteoporotic model, compared with the OLIF model of normal bone. Therefore, the biomechanical performance of an osteoporotic model may be inferior to the biomechanical performance of a normal model for the same fixation method; in some instances, it may increase the risks of fracture and internal fixation failure.

Three-dimensional computed tomographic evaluation of lateral lumbar interbody fusion: morphometric change of intervertebral structure

PURPOSE

Two-dimensional (2D) analyses of intervertebral disc (IVD) height and foramen measurements following lateral lumbar interbody fusion (LLIF) have been reported. However, three-dimensional (3D) morphometric analysis of intervertebral structure using 3D computed tomography (3D CT) provides increased precision for measuring morphological changes. The purpose of this study was to evaluate 3D changes of lumbar IVD height and foramen diameter in degenerative lumbar disease patients following LLIF.

METHODS

Subject-based 3D CT lumbar models were created for 26 patients before and following LLIF. IVD height (whole and five anatomical zones) and foramen diameter (minimum and maximum) were measured based on the model using custom software. The sagittal placement of cages (SPC) and cross-sectional area of the thecal sac (CSA) were measured. Changes in these parameters by LLIF were quantified and statistically analysed.

RESULTS

Following LLIF, disc height increased by an average of 2.9 mm (P < 0.01). Post-operative measurements of both minimum and maximum diameters of the foramen were significantly increased by 1.0 mm and 1.9 mm, respectively (P < 0.01). Change in maximum foramen diameter was significantly correlated with change in disc height (P < 0.05). The SPC was significantly correlated with the changes in disc height and foraminal diameters (P < 0.05, respectively). No significant change between the change in disc height and CSA was found.

CONCLUSION

This preliminary study quantifies disc height and foramen diameter changes in 3D following LLIF. The presented data provide baseline intervertebral changes for future comparisons with follow-up studies and clinical outcomes.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Biomechanical Evaluation of Oblique Lumbar Interbody Fusion with Various Fixation Options: A Finite Element Analysis

Objective

The aim of the present study was to clarify the biomechanical properties of oblique lumbar interbody fusion (OLIF) using different fixation methods in normal and osteoporosis spines.

Methods

Normal and osteoporosis intact finite element models of L₁–S₁ were established based on CT images of a healthy male volunteer. Group A was the normal models and group B was the osteoporosis model. Each group included four subgroups: (i) intact; (ii) stand‐alone cage (Cage); (iii) cage with lateral plate and two lateral screws (LP); and (iv) cage with bilateral pedicle screws and rods (BPSR). The L₃–L₄ level was defined as the surgical segment. After validating the normal intact model, compressive load of 400 N and torsional moment of 10 Nm were applied to the superior surface of L₂ to simulate flexion, extension, left bending, right bending, left rotation, and right rotation motions. Surgical segmental range of motion (ROM), cage stress, endplate stress, supplemental fixation stress, and stress distribution were analyzed in each group.

Results

Cage provided the minimal reduction of ROM among all motions (normal, 82.30%–98.81%; osteoporosis, 92.04%–97.29% of intact model). BPSR demonstrated the maximum reduction of ROM (normal, 43.94%–61.13%; osteoporosis, 45.61%–62.27% of intact model). The ROM of LP was between that of Cage and BPSR (normal, 63.25%–79.72%; osteoporosis, 70%–87.15% of intact model). Cage had the minimal cage stress and endplate stress. With the help of LP and BPSR fixation, cage stress and endplate stress were significantly reduced in all motions, both in normal and osteoporosis finite element models. However, BPSR had more advantages. For cage stress, BPSR was at least 75.73% less than that of Cage in the normal model, and it was at least 80.10% less than that of Cage in the osteoporosis model. For endplate stress, BPSR was at least 75.98% less than that of Cage in the normal model, and it was at least 78.06% less than that of Cage in the osteoporosis model. For supplemental fixation stress, BPSR and LP were much less than the yield strength in all motions in the two groups. In addition, the comparison between the two groups showed that the ROM, cage stress, endplate stress, and supplemental fixation stress in the normal model were less than in the osteoporosis model when using the same fixation option of OLIF.

Conclusion

Oblique lumbar interbody fusion with BPSR provided the best biomechanical stability both in normal and osteoporosis spines. The biomechanical properties of the normal spine were better than those of the osteoporosis spine when using the same fixation option of OLIF.

Clinical experience of extreme lateral interbody fusion in the treatment of lumbar spondylodiscitis

Introduction

Up to now, there were few studies on extreme lateral interbody fusion (XLIF) surgery for lumbar spondylodiscitis. This study was aimed to evaluate clinical effectiveness and provide more information for XLIF in the treatment of lumbar spondylodiscitis.

Methods

We retrospectively collected cases of XLIF for the treatment of lumbar spondylodiscitis from September 2017 to February 2020. There were 8 cases of non-specific infection of lumbar spine, 4 cases of lumbar tuberculosis, and 1 case of lumbar brucellosis. Basic information, antibiotic application, and inflammatory index were collected before and after surgery. Clinical effectiveness was evaluated at baseline and in 3, 6, and 12 months after the surgery with visual analog scale (VAS) and Oswestry disability index (ODI). The comparison of the indicators before and after the operation was performed by repeated measures analysis of variance.

Results

The average intraoperative blood loss and operation time was 70mL and 99.23 min, respectively. The study consisted of 13 cases with single segment operation. The average follow-up time was 16.54 months. No sign of recurrence of spondylodiscitis occurred at last follow-up. Postoperative VAS and ODI were significantly decreased after the operation. No major blood vessels, nerves, or organ damage occurred during the perioperative period.

Conclusion

XLIF has shown good clinical effectiveness in the treatment of lumbar spondylodiscitis with advantages of less bleeding and less tissue damage in the present study. More multi-center prospective comparative studies are needed to further verify the clinical effectiveness of this procedure in lumbar spondylodiscitis.

The impact of increasing interbody fusion levels at the fractional curve on lordosis, curve correction, and complications in adult patients with scoliosis

OBJECTIVE

Radiculopathy from the fractional curve, usually from L3 to S1, can create severe disability. However, treatment methods of the curve vary. The authors evaluated the effect of adding more levels of interbody fusion during treatment of the fractional curve.

METHODS

A single-institution retrospective review of adult patients treated for scoliosis between 2006 and 2016 was performed. Inclusion criteria were as follows: fractional curves from L3 to S1 > 10°, ipsilateral radicular symptoms concordant on the fractional curve concavity side, patients who underwent at least 1 interbody fusion at the level of the fractional curve, and a minimum 1-year follow-up. Primary outcomes included changes in fractional curve correction, lumbar lordosis change, pelvic incidence - lumbar lordosis mismatch change, scoliosis major curve correction, and rates of revision surgery and postoperative complications. Secondary analysis compared the same outcomes among patients undergoing posterior, anterior, and lateral approaches for their interbody fusion.

RESULTS

A total of 78 patients were included. There were no significant differences in age, sex, BMI, prior surgery, fractional curve degree, pelvic tilt, pelvic incidence, pelvic incidence - lumbar lordosis mismatch, sagittal vertical axis, coronal balance, scoliotic curve magnitude, proportion of patients undergoing an osteotomy, or average number of levels fused among the groups. The mean follow-up was 35.8 months (range 12-150 months). Patients undergoing more levels of interbody fusion had more fractional curve correction (7.4° vs 12.3° vs 12.1° for 1, 2, and 3 levels; p = 0.009); greater increase in lumbar lordosis (-1.8° vs 6.2° vs 13.7°, p = 0.003); and more scoliosis major curve correction (13.0° vs 13.7° vs 24.4°, p = 0.01). There were no statistically significant differences among the groups with regard to postoperative complications (overall rate 47.4%, p = 0.85) or need for revision surgery (overall rate 30.7%, p = 0.25). In the secondary analysis, patients undergoing anterior lumbar interbody fusion (ALIF) had a greater increase in lumbar lordosis (9.1° vs -0.87° for ALIF vs transforaminal lumbar interbody fusion [TLIF], p = 0.028), but also higher revision surgery rates unrelated to adjacent-segment pathology (25% vs 4.3%, p = 0.046). Higher ALIF revision surgery rates were driven by rod fracture in the majority (55%) of cases.

CONCLUSIONS

More levels of interbody fusion resulted in increased lordosis, scoliosis curve correction, and fractional curve correction. However, additional levels of interbody fusion up to 3 levels did not result in more postoperative complications or morbidity. ALIF resulted in a greater lumbar lordosis increase than TLIF, but ALIF had higher revision surgery rates.

Lateral Lumbar Interbody Fusion: What Is the Evidence of Indirect Neural Decompression? A Systematic Review of the Literature

BACKGROUND

In the past decade, lateral lumbar interbody fusion (LLIF) has gained in popularity. A proposed advantage is the achievement of indirect neural decompression. However, evidence of the effectiveness of LLIF in neural decompression in lumbar degenerative conditions remains unclear.

QUESTIONS/PURPOSES

We sought to extrapolate clinical and radiological results and consequently the potential benefits and limitations of LLIF in indirect neural decompression in degenerative lumbar diseases.

METHODS

We conducted a systematic review of the literature in English using the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and checklist. Scores on the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain were extracted, as were data on the following radiological measurements: disc height (DH), foraminal height (FH), foraminal area (FA), central canal area (CA).

RESULTS

In the 42 articles included, data on 2445 patients (3779 levels treated) with a mean follow-up of 14.8 ± 5.9 months were analyzed. Mean improvements in VAS back, VAS leg, and ODI scale scores were 4.1 ± 2.5, 3.9 ± 2.2, and 21.9 ± 7.2, respectively. Post-operative DH, FH, FA, and CA measurements increased by 68.6%, 21.9%, 37.7%, and 29.3%, respectively.

CONCLUSION

Clinical results indicate LLIF as an efficient technique in indirect neural decompression. Analysis of radiological data demonstrates the effectiveness of symmetrical foraminal decompression. Data regarding indirect decompression of central canal and lateral recess are inconclusive and contradictory. Bony stenosis appears as an absolute contraindication. The role of facet joint degeneration is unclear. This systematic review provides a reference for surgeons to define the potential and limitations of LLIF in indirect neural elements decompression.

Reduction in foraminal height after lateral access surgery does not affect quality of life: A 2-year outcome study on lateral lumbar interbody fusion

INTRODUCTION

Reduction in neuroforaminal height (FH) may diminish the indirect decompression benefit that lateral access surgery (LAS) provides. However, the relationship between postoperative FH reduction in LAS and health-related quality-of-life (HRQoL) outcomes remains unclear.

OBJECTIVES

To determine whether FH reduction affects HRQoL outcomes at 2-year follow-up.

METHODS

A retrospective review of 45 patients who underwent LAS for degenerative lumbar spine conditions was performed. The cohort was divided into two groups: maintenance (A) and reduction (B) in FH. Outcome measures included numerical pain rating scale (NPRS back and leg pain), Oswestry Disability Index (ODI), Short Form 36 Health Survey (SF-36), North American Spine Society (NASS) score for neurogenic symptoms (NS), patient satisfaction, and expectation fulfilment for surgery. Mean disc height (DH), FH, and fusion were evaluated on plain radiographs. Radiological fusion was assessed with the Bridwell fusion classification. Unpaired student's t-test was used to compare between groups and one-way ANOVA with Bonferroni post hoc correction was used to determine differences between time intervals within each group.

RESULTS

The average pre-op mean FH was 16.9 ± 3.5 mm. Group A had 25 patients showing postoperative maintenance of FH (19.4 ± 3.3 mm to 20.2 ± 3.2 mm; 4% increase) at 2-year postsurgery while group B had 20 patients showing decrease in FH (21.1 ± 3.3 mm to 18.7 ± 3.5 mm; 11% decrease). Group A mean DH improved from 7.0 ± 2.0 mm to 10.3 ± 1.6 mm (47% increase). Group B mean DH improved from 6.8 ± 2.3 mm to 11.0 ± 3.0 mm (62% increase). There were no significant differences in NPRS, ODI, NASS, SF-36, and SF-36 MCS/PCS between groups at 2 years ( p > 0.05); 92% of group A and 85% of group B patients reported good satisfaction and fulfilment of expectations ( p > 0.05).

CONCLUSION

Despite an initial increase in FH after LAS surgery, 45% of patients had FH reduction at 2 years. However, FH reduction up to 11% did not affect short-term HRQoL outcomes.

Lateral Lumbar Interbody Fusion (LLIF): An Update

Degenerative lumbar spine disease (DLSD) is a heterogenous group of conditions that can significantly affect patients' quality of life. Lateral lumbar interbody fusion (LLIF) is one of the treatment modalities for DLSD that has been increasing in popularity over the past decade. The treatment of DLSD should be individualized based on patients' symptoms and characteristics to maximize outcomes.

METHODS

Literature review, invited review.

RESULTS

In this article, we will (1) review the use of the LLIF technique in the treatment of degenerative lumbar spine disease, (2) review the current concepts of LLIF, and (3) explore the evidence to date that will allow the reader to maximize the benefits of this technique.

CONCLUSIONS

LLIF is an alternative for the treatment of degenerative pathologies of the lumbar spine via indirect decompression.

Prone single-position extreme lateral interbody fusion (Pro-XLIF): preliminary results

BACKGROUND

Single-position options for combined anterior and posterior fusion in the lumbar spine have been suggested to reduce the surgical time and improve the efficiency of operating room. Previous reports have focused on lateral decubitus single-position surgery. The goal of this study is to describe and evaluate the feasibility and safety of prone single-position extreme lateral interbody fusion (XLIF) with posterior fixation.

METHODS

Design Pilot prospective non-randomized controlled study. Seven patients who underwent prone single-position XLIF and posterior fixation were evaluated (Pro-XLIF). A control group (Std-XLIF) was composed of ten patients who underwent XLIF in lateral decubitus and posterior fixation in prone position. All patients underwent interbody XLIF fusion at one level and posterior procedures at one or more levels. Duration of surgery, blood loss, complications, X-ray use and clinical outcomes were recorded.

RESULTS

No major complications were observed in either group. Oswestry Disability Index, back pain and leg pain were improved in the Pro-XLIF group from 48.5, 7.7 and 8.5 to 14.5, 1.71 and 2.71, respectively, and in the Std-XLIF group from 50.8, 5.7 and 7.2 to 22.5, 3.7 and 2.5. The Pro-XLIF group had a longer time of preparation before incision (39 vs 26 min, ns), equal duration of the anterior procedure (65 vs 59 min, ns), shorter duration of surgery (133 vs 182 min, ns) and longer X-ray exposure time (102 vs 92 s, ns). The surgical technique is described.

CONCLUSIONS

Prone single-position XLIF is feasible and safe. In this preliminary report, the results are comparable to the standard technique. These slides can be retrieved under Electronic Supplementary Material.

Scoliosis surgery in adulthood: what challenges for what outcome?

Adolescent idiopathic scoliosis that has progressed over time, de novo scoliosis, and degenerative scoliosis represent different types of adult spinal deformity (ASD). Functional impairment and muscular fatigue are due to sagittal and coronal imbalance of the trunk. Surgical treatment can provide a significant improvement of three-dimensional (3D) thoracolumbar alignment, function, and health-related quality of life (QoL). A patient-specific benefit-risk assessment, including clinical expectations, comorbidities, and the spinal deformity itself, has to be done preoperatively since the risk for mechanical complications is relatively high. Minimal invasive techniques combine posterior percutaneous instrumentation and lateral interbody fusion cages which enables vertebral realignment and indirect foraminal stenosis decompression. This strategy seems appropriate in mild and moderate ASD with a limited number of degenerated segments in the lumbar spine and remaining curve flexibility. Severe ASD needs to be addressed by open surgery, which combines posterior instrumentation, interbody fusion, and osteotomies in stiff deformities. Longer posterior instrumentation of the thoracolumbar spine, the sacrum, and the pelvis carries a risk for mechanical complications such as non-union and proximal junctional kyphosis (PJK). Modern surgical techniques including circumferential lumbosacral fusion and double rods might lower the risk for non-union. Accurate sagittal alignment planning, setting the lumbar sagittal apex according to pelvic incidence, and segmental lordosis distribution, are mandatory for minimizing the risk of PJK.

Differences in radiographic and clinical outcomes of oblique lateral interbody fusion and lateral lumbar interbody fusion for degenerative lumbar disease: a meta-analysis

Background

In the current surgical therapeutic regimen for the degenerative lumbar disease, both oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) are gradually accepted. Thus, the objective of this study is to compare the radiographic and clinical outcomes of OLIF and LLIF for the degenerative lumbar disease.

Methods

We conducted an exhaustive literature search of MEDLINE, EMBASE, and the Cochrane Library to find the relevant studies about OLIF and LLIF for the degenerative lumbar disease. Random-effects model was performed to pool the outcomes about disc height (DH), fusion, operative blood loss, operative time, length of hospital stays, complications, visual analog scale (VAS), and Oswestry disability index (ODI).

Results

56 studies were included in this study. The two groups of patients had similar changes in terms of DH, operative blood loss, operative time, hospital stay and the fusion rate (over 90%). The OLIF group showed slightly better VAS and ODI scores improvement. The incidence of perioperative complications of OLIF and LLIF was 26.7 and 27.8% respectively. Higher rates of nerve injury and psoas weakness (21.2%) were reported for LLIF, while higher rates of cage subsidence (5.1%), endplate damage (5.2%) and vascular injury (1.7%) were reported for OLIF.

Conclusions

The two groups are similar in terms of radiographic outcomes, operative blood loss, operative time and the length of hospital stay. The OLIF group shows advantages in VAS and ODI scores improvement. Though the incidence of perioperative complications of OLIF and LLIF is similar, the incidence of main complications is significantly different.

Treatment of only the fractional curve for radiculopathy in adult scoliosis: comparison to lower thoracic and upper thoracic fusions

OBJECTIVE

Many options exist for the surgical management of adult spinal deformity. Radiculopathy and lumbosacral pain from the fractional curve (FC), typically from L4 to S1, is frequently a reason for scoliosis patients to pursue surgical intervention. The purpose of this study was to evaluate the outcomes of limited fusion of the FC only versus treatment of the entire deformity with long fusions.

METHODS

All adult scoliosis patients treated at the authors' institution in the period from 2006 to 2016 were retrospectively analyzed. Patients with FCs from L4 to S1 > 10° and radiculopathy ipsilateral to the concavity of the FC were eligible for study inclusion and had undergone three categories of surgery: 1) FC only (FC group), 2) lower thoracic to sacrum (LT group), or 3) upper thoracic to sacrum (UT group). Primary outcomes were the rates of revision surgery and complications. Secondary outcomes were estimated blood loss, length of hospital stay, and discharge destination. Spinopelvic parameters were measured, and patients were stratified accordingly.

RESULTS

Of the 99 patients eligible for inclusion in the study, 27 were in the FC group, 46 in the LT group, and 26 in the UT group. There were no significant preoperative differences in age, sex, smoking status, prior operation, FC magnitude, pelvic tilt (PT), sagittal vertical axis (SVA), coronal balance, pelvic incidence-lumbar lordosis (PI-LL) mismatch, or proportion of well-aligned spines (SVA < 5 cm, PI-LL mismatch < 10°, and PT < 20°) among the three treatment groups. Mean follow-up was 30 (range 12-112) months, with a minimum 1-year follow-up. The FC group had a lower medical complication rate (22% [FC] vs 57% [LT] vs 58% [UT], p = 0.009) but a higher rate of extension surgery (26% [FC] vs 13% [LT] vs 4% [UT], p = 0.068). The respective average estimated blood loss (592 vs 1950 vs 2634 ml, p < 0.001), length of hospital stay (5.5 vs 8.3 vs 8.3 days, p < 0.001), and rate of discharge to acute rehabilitation (30% vs 46% vs 85%, p < 0.001) were all lower for FC and highest for UT.

CONCLUSIONS

Treatment of the FC only is associated with a lower complication rate, shorter hospital stay, and less blood loss than complete scoliosis treatment. However, there is a higher associated rate of extension of the construct to the lower or upper thoracic levels, and patients should be counseled when considering their options.

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

STUDY DESIGN

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Impact of Cage Dimensions, Positioning, and Side of Approach in Extreme Lateral Interbody Fusion

STUDY DESIGN

This is a retrospective single-center study.

OBJECTIVE

The aim of the study was to evaluate the impact of cage characteristics and position toward clinical and radiographic outcome measures in patients undergoing extreme lateral interbody fusion (ELIF).

SUMMARY OF BACKGROUND DATA

ELIF is utilized for indirect decompression and minimally invasive surgical treatment for various degenerative spinal disorders. However, evidence regarding the influence of cage characteristics in patient outcome is minimal.

MATERIALS AND METHODS

Patients undergoing ELIF between 2007 and 2011 were included in a retrospective study. Demographic and perioperative data, as well as cage characteristics and side of approach were extracted. Radiographic parameters including lumbar lordosis, foraminal height, and disc height as well as clinical outcome parameters (Oswestry Disability Index and Visual Analog Scale) were measured preoperatively, postoperatively, and at the latest follow-up examination. Cage dimensions, in situ position, and type were correlated with radiographic and clinical outcome parameters.

RESULTS

In total, 84 patients with a total of 145 functional spinal units were analyzed. At the last follow-up of 17.7 months, radiographic and clinical outcome measures revealed significant improvement compared with before surgery with both, 18 and 22 mm cage anterior-posterior diameter subgroups (P≤0.05). Among cage characteristics, 22 mm cages presented superior restoration of foraminal and disc heights compared with 18 mm cages (P≤0.05). Neither position of the cage (anterior vs. posterior), nor the type (parallel vs. lordotic) had a significant impact on restoration of foraminal height and lumbar lordosis. Moreover, the side of surgical approach did not influence the amount of foraminal height increase.

CONCLUSIONS

Cage anterior-posterior diameter is the determining factor in restoration of foraminal height in ELIF. Cage height, type, positioning, and side of approach do not have a determining role in radiographic outcome in the present study. Sustainable foraminal height restoration is achieved by implantation of wider cages.

LEVEL OF EVIDENCE

Level 3.

Effect of three-dimensional rotational deformity correction in surgery for adult degenerative scoliosis using lumbar lateral interbody fusion and posterior pedicle screw fixation

Introduction

Corrective surgery for adult degenerative scoliosis using lateral interbody fusion (LIF) and additional posterior fixation is an efficient procedure. However, it is unclear how this procedure affects rotational deformity correction. Therefore, the goal of the present study was to use three-dimensional (3D) images, taken during surgery, to investigate rotational deformity correction in the treatment of adult degenerative scoliosis using LIF and posterior fixation using a pedicle screw system.

Methods

The subjects were 12 females who were treated using LIF and posterior fixation for adult degenerative scoliosis. The patients had a mean age of 72 (65-76) years. 3D images were acquired before surgery, after LIF, and after additional posterior fixation. Rotational angles of the upper vertebra with respect to the lower vertebra of each fixed segment were measured in 3 planes. Correction factors for rotational deformity were investigated after LIF and additional posterior fixation.

Results

There were significant improvements in radiographical parameters for global spinal balance. The correction angles per segment were 4.7° for lateral bending, 6.9° for lordosis, and 4.5° for axial rotation. LIF was responsible for correction of four-fifths of lateral bending and axial rotation, and two-thirds of lordotic changes.

Conclusions

Lateral bending, axial rotational deformities, and lordosis were primarily corrected by LIF. Further lordosis correction was achieved using additional posterior fixation. These results indicate that corrective surgery for adult degenerative scoliosis using these procedures is effective for rotational deformity correction and leads to an ideal global spinal alignment.

Effect of Single-Level Transforaminal Lumbar Interbody Fusion on Segmental and Overall Lumbar Lordosis in Patients with Lumbar Degenerative Disease

OBJECTIVE

To investigate the ability of transforaminal lumbar interbody fusion (TLIF) to improve lumbar lordosis (LL).

METHODS

In this retrospective study, 92 patients undergoing single-level TLIF to treat lumbar degenerative disease were divided into a low back pain, radiculopathy, and neurogenic claudication group according to their symptoms. Preoperative and postoperative measures, including segmental LL, whole LL, pelvic incidence (PI), pelvic tilt, thoracic kyphosis, sagittal vertical axis, visual analog scale for back and leg pain, and Oswestry Disability Index, were used to evaluate radiographic and clinical outcomes.

RESULTS

All clinical parameters were significantly improved after TLIF. There was no significant difference in any radiographic parameters in the low back pain group. In the radiculopathy and neurogenic claudication groups, all radiographic parameters were significantly changed after TLIF except for segmental LL and PI in both groups and pelvic tilt in the radiculopathy group. No statistically significant differences were found in improvement of segmental LL, PI, thoracic kyphosis, and visual analog scale (leg) between the radiculopathy and neurogenic claudication groups, whereas the differences in improvement of whole LL, pelvic tilt, PI-LL, sagittal vertical axis, visual analog scale (back), and Oswestry Disability Index were significant between the 2 groups.

CONCLUSIONS

For patients with neurogenic leg symptoms owing to single-level lumbar degenerative disease, whole LL was improved after TLIF as a result of spontaneous restoration of lordosis at the unfused lumbar levels.

Percutaneous full endoscopic lumbar foraminoplasty for adjacent level foraminal stenosis following vertebral intersegmental fusion in an awake and aware patient under local anesthesia: A case report

Percutaneous endoscopic surgery for the lumbar spine has become established in the last decade. It requires only an 8 mm skin incision, causes minimal damage to the paravertebral muscles, and can be performed under local anesthesia. With the advent of improved equipment, in particular the high-speed surgical drill, the indications for percutaneous endoscopic surgery have expanded to include lumbar spinal canal stenosis. Transforaminal percutaneous endoscopic discectomy has been used to treat intervertebral stenosis. However, it has been reported that adjacent level disc degeneration and foraminal stenosis can occur following intervertebral segmental fusion. When this adjacent level pathology becomes symptomatic, additional fusion surgery is often needed. We performed minimally invasive percutaneous full endoscopic lumbar foraminoplasty in an awake and aware 50-year-old woman under local anesthesia. The procedure was successful with no complications. Her radiculopathy, including muscle weakness and leg pain due to impingement of the exiting nerve, improved after the surgery. J. Med. Invest. 64: 291-295, August, 2017.

A novel diagnostic parameter, foraminal stenotic ratio using three-dimensional magnetic resonance imaging, as a discriminator for surgery in symptomatic lumbar foraminal stenosis

BACKGROUND CONTEXT

No previous studies have reported the radiological features of patients requiring surgery in symptomatic lumbar foraminal stenosis (LFS).

PURPOSE

This study aims to investigate the diagnostic accuracy of a novel technique, foraminal stenotic ratio (FSR), using three-dimensional magnetic resonance imaging for LFS at L5-S by comparing patients requiring surgery, patients with successful conservative treatment, and asymptomatic patients.

STUDY DESIGN

This is a retrospective radiological comparative study.

PATIENT SAMPLE

We assessed the magnetic resonance imaging (MRI) results of 84 patients (168 L5-S foramina) aged ≥40 years without L4-L5 lumbar spinal stenosis. The foramina were divided into three groups following standardized treatment: stenosis requiring surgery (20 foramina), stenosis with successful conservative treatment (26 foramina), and asymptomatic stenotic foramen (122 foramina).

OUTCOME MEASURES

Foraminal stenotic ratio was defined as the ratio of the length of the stenosis to the length of the foramen on the reconstructed oblique coronal image, referring to perineural fat obliterations in whole oblique sagittal images. We also evaluated the foraminal nerve angle and the minimum nerve diameter on reconstructed images, and the Lee classification on conventional T1 images.

MATERIALS AND METHODS

The differences in each MRI parameter between the groups were investigated. To predict which patients require surgery, receiver operating characteristic (ROC) curves were plotted after calculating the area under the ROC curve.

RESULTS

The FSR showed a stepwise increase when comparing asymptomatic, conservative, and surgical groups (mean, 8.6%, 38.5%, 54.9%, respectively). Only FSR was significantly different between the surgical and conservative groups (p=.002), whereas all parameters were significantly different comparing the symptomatic and asymptomatic groups. The ROC curve showed that the area under the curve for FSR was 0.742, and the optimal cutoff value for FSR for predicting a surgical requirement in symptomatic patients was 50% (sensitivity, 75%; specificity, 80.7%).

CONCLUSIONS

The FSR determined LFS requiring surgery among symptomatic patients, with moderate accuracy. Foramina occupied ≥50% by fat obliteration were likely to fail conservative treatment, with a positive predictive value of 75%.

Adult spinal deformity: effectiveness of interbody lordotic cages to restore disc angle and spino-pelvic parameters through completely mini-invasive trans-psoas and hybrid approach

PURPOSE

The aim of the study is to assess and quantify the effectiveness of interbody lordotic cages applied by trans-psoas approach to improve radiographic parameters, showing the differences between completely mini-invasive and hybrid approach.

METHODS

We collected data of 65 patients affected by degenerative lumbar deformity/diseases and underwent mini-invasive lateral interbody fusion followed by percutaneous (group A, completely mini-invasive) or open (group B, hybrid) posterior instrumentation. A subgroup underwent anterior column realignment (ACR). We assessed statistical differences in preoperative and postoperative (at least 6-month) coronal and sagittal parameters, and disc angle (DA) at each level of cage application.

RESULTS

107 lordotic cages were implanted. Group B had the most significant mean changes, especially in coronal Cobb angle, sagittal vertical axis, lumbar lordosis (LL), pelvic incidence-LL mismatch and DA. Concerning DA, at each level of lordotic cage application, in group A changed from -2.9° preop to -6.5° postop (p = 0.01); in group B, DA changed from -2.6° to -9.5° (p = 0.002) and from +1° to -13.2° in patients underwent ACR.

CONCLUSIONS

Minimally invasive lateral lumbar interbody fusion is an effective technique in improving sagittal parameters. When combined with posterior open approach and/or application of ACR procedure greater corrections are possible.

Early experience with endoscopic foraminotomy in patients with moderate degenerative deformity

OBJECTIVE Asymmetrical degeneration of the disc is one of the most common causes of primary degenerative scoliosis in adults. Coronal deformity is usually less symptomatic than a sagittal deformity because there is less expenditure of energy and hence less effort to maintain upright posture. However, nerve root compression at the fractional curve or at the concave side of the main curve can give rise to debilitating radiculopathy. METHODS This study was a retrospective analysis of 16 patients with coronal deformity of between 10° and 20°. All patients underwent endoscopic foraminal decompression surgery. The pre- and postoperative Cobb angle, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36), and Oswestry Disability Index scores were measured. RESULTS The average age of the patients was 70.0 ± 15.5 years (mean ± SD, range 61-86 years), with a mean followup of 7.5 ± 5.3 months (range 2-14 months). The average coronal deformity was 16.8° ± 4.7° (range 10°-41°). In 8 patients the symptomatic foraminal stenosis was at the level of the fractional curve, and in the remaining patients it was at the concave side of the main curve. One of the patients included in the current cohort had to undergo a repeat operation within 1 week for another disc herniation at the adjacent level. One patient had CSF leakage, which was repaired intraoperatively, and no further complications were noted. On average, preoperative VAS and SF-36 scores showed a tendency for improvement, whereas a dramatic reduction of VAS, by 65% (p = 0.003), was observed in radicular leg pain. CONCLUSIONS Patients with mild to moderate spinal deformity are often compensated and have tolerable levels of back pain. However, unilateral radicular pain resulting from foraminal stenosis can be debilitating. In select cases, an endoscopic discectomy or foraminotomy enables the surgeon to decompress the symptomatic foramen with preservation of essential biomechanical structures, delaying the need for a major deformity correction surgery.

Extreme lateral lumbar interbody fusion: Do the cons outweigh the pros?

BACKGROUND

Major factors prompted the development of minimally invasive (MIS) extreme lateral interbody fusion (XLIF; NuVasive Inc., San Diego, CA, USE) for the thoracic/lumbar spine. These include providing interbody stabilization and indirect neural decompression while avoiding major visceral/vessel injury as seen with anterior lumbar interbody fusion (ALIF), and to avert trauma to paraspinal muscles/facet joints found with transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), and posterior-lateral fusion techniques (PLF). Although anticipated pros of MIS XLIF included reduced blood loss, operative time, and length of stay (LOS), they also included, higher fusion, and lower infection rates. Unanticipated cons, however, included increased morbidity/mortality rates.

METHODS

We assessed the pros and cons (e.g., risks, complications, comparable value/superiority/inferiority, morbidity/mortality) of MIS XLIF vs. ALIF, TLIF, PLIF, and PLF.

RESULTS

Pros of XLIF included various biomechanical and technical surgical advantages, along with multiple cons vs. ALIF, TLIF, PLIF, and PLF. For example, XLIF correlated with a considerably higher frequency of major neurological deficits vs. other constructs; plexus injuries 13.28%, sensory deficits 0-75% (permanent in 62.5%), motor deficits 0.7-33.6%, and anterior thigh pain 12.5-25%. XLIF also disproportionately contributed to other major morbidity/mortality; sympathectomy, major vascular injuries (some life-ending others life-threatening), bowel perforations, and seromas. Furthermore, multiple studies documented no superiority, and the potential inferiority of XLIF vs. ALIF, TLIF, PLIF, and PLF.

CONCLUSION

Reviewing the pros of XLIF (e.g. radiographic, technical, biomechanical) vs. the cons (inferiority, increased morbidity/mortality) vs. ALIF, TLIF, PLIF, and PLF, we question whether XLIF should remain part of the lumbar spinal surgical armamentarium.

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

BACKGROUND CONTEXT

Spine surgeons must correlate clinical presentation with radiographic findings in a patient-tailored approach. Despite the prevalence of adult degenerative scoliosis (ADS), there are few radiographic markers to predict the presence of radiculopathy. Emerging data suggest that spondylolisthesis, obliquity, foraminal stenosis, and curve concavity may be associated with radiculopathy in ADS.

PURPOSE

The purpose of this study was to determine if radicular pain in ADS is associated with reduced interpedicular heights (IPHs) as measured on routine radiographs.

STUDY DESIGN/SETTING

This is a retrospective case-controlled study.

PATIENT SAMPLE

The authors carried out a retrospective chart review at a tertiary care referral center that included ADS patients referred to scoliosis surgeons between 2012 and 2014. Inclusion criteria included patients with ADS and no prior thoracolumbar surgery. Data were collected from initial spine surgeon clinic notes and radiographs.

OUTCOME MEASURES

Clinical outcome data included presence, side(s), and level(s) of radicular pain; presence of motor deficits; and presence of sensory deficits.

METHODS

Variables included age, gender, Scoliosis Research Society-30 (SRS-30) and Oswestry Disability Index (ODI) questionnaire data, and radiographic measurements. Radiographic measurements included Cobb angles and L1 to S1 IPHs on upright and supine radiographs. Associations between variables and outcome measures were assessed with univariate and multivariate statistical analyses. Authors have no conflicts of interests relevant to this study.

RESULTS

A total of 200 patients with an average age of 51 years met the inclusion criteria. Sixty of the 200 patients presented with radicular pain. Older age was associated with radicular pain, weakness, and sensory deficits. Patients who were 55 years or older were approximately eight times more likely to have radicular pain (odds ratio [OR]=7.96, 95% confidence interval [CI]: 3.73, 17.0; p<.001), five times more likely to have motor deficit (OR=5, 95% CI: 2.55, 9.79; p<.001), and five times more likely to have sensory deficit (OR=5.2, 95% CI: 2.65, 10.2; p<.001) than those younger than 55. More caudally located nerve roots are more likely to develop radicular pain (p<.001). Motor deficits were associated with worse SRS-30 functional (p=.02) and ODI scores (p=.005), but radicular pain and sensory deficits were not associated with lower SRS-30 or ODI scores. Ipsilateral and same-level radicular pain were associated with reduced IPH on supine radiographs (p=.002 and p=.0002, respectively). Finally, reduced IPH on upright radiographs was associated with side- and level-specific radicular pain (p=.04).

CONCLUSIONS

Radicular pain in ADS patients is associated with reduced IPHs and older age. Measuring IPHs on routine radiographs may be helpful in associating clinical radiculopathy with radiographic measures to guide patient management and surgical planning.

Lumbar Neuroforaminal Decompression with a Flexible Microblade Shaver System: Results of a Cadaveric Study

BACKGROUND

The lumbar neural foraminal stenosis still is a challenging condition in minimally invasive spine surgery. Because of the anatomic situation a complete decompression of the nerve root often leads to a subtotal facetectomy associated with potential instability and the need for additional instrumentation of the decompressed segment. The iO-Flex system was introduced to address this problem by using a minimally invasive wire-guided microblade shaver to increase the neuroforaminal space by reducing the stenosis from intraforaminal while sparing bigger parts of the facet joint. In this study, we evaluated the feasibility and the surgical and radiological success in relation to the experience of the surgeon.

METHODS

We performed decompression of the neuroforamen in 10 lumbar levels of 2 fresh-frozen human cadavers. Before and after decompression, we obtained high-resolution computed tomography data to evaluate the diameter of the neural foramen.

RESULTS

The mean foraminal width (7.88-10.94 mm, P < 0.0001) and area (123.27-149.18 mm², P < 0.003) increased significantly after the decompression, whereas the facet joints area (131.9-107.51 mm², P < 0.005) and width (16.4-13.75 mm, P < 0.001) indeed decreased significantly but with an overall reduction of facet joint width by 16% and facet joint area by 18%. No complications such as nerve root damages or dural tears were observed.

CONCLUSIONS

The flexible micro blade shaver system is feasible with a steep learning curve and achieves sufficient decompression of the neuroforamen in this cadaveric study.

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

Purpose: The purpose of this study is to define an algorithm that will predict the success of indirect decompression without the need for direct decompression in patients undergoing lateral lumbar interbody fusions.

Methods and Materials: A prospective cohort study was undertaken for patients undergoing indirect decompression with lateral lumbar interbody fusion. Patients had to meet the following criteria prior to indirect fusion: lack of facet fusion on CT, absence of free disc fragment or compressive facet joint cyst on MRI, absence of frank osteoporosis, lack of congenital and/or severe spinal stenosis on MRI, and significant reduction (greater than 50%) in leg and back pain at rest. We then assessed which patients at follow-up required a second stage open decompression procedure because of continued back and/or leg pain.  

Results: Our series included 28 patients who underwent indirect decompression with extreme lateral lumbar interbody fusion. Of the 28 patients, one patient required a second stage open decompression at follow-up. The most common level operated on was the L4-L5 level. Twelve patients underwent more than a single level fusion. Average preoperative lumbar lordosis was 29 degrees and average postoperative lordosis was 45 degrees. The average patient age was 66.3 years and average follow-up was 1.21 years.  

Conclusions: Our algorithm can be used as an aid to assess which patients may benefit from indirect decompression alone, compared to indirect decompression combined with posterior decompression procedures.