Clinical and Radiological Results After Minimally Invasive Transpsoas Lateral Access Surgery for Degenerative Lumbar Stenosis

Study Design: Prospective cohort study. Objective: The lateral transpsoas access is a retroperitoneal approach for the lumbar spine to perform the lateral lumbar interbody fusion (LLIF), an intersomatic arthrodesis performed with a cage placed on the lateral borders of the epiphyseal ring. The procedure can be used to provide indirect decompression of the nervous structures through the discectomy and restoration of the disc height. The objective of the present study was to evaluate the indirect decompression following LLIF both with radiological and clinical parameters. Methods: Prospective clinical and radiological study in a single center with 20 patients diagnosed with 1- or 2-level degenerative lumbar stenosis. Radiological analysis on magnetic resonance imaging included foramen height, canal area, canal diameter, and disc height. Clinical outcomes included visual analogue scale (VAS) and Oswestry Disability Index (ODI) collected up to 12 months. Complications and reoperations were recorded. Results: In total, 25 levels were treated. No reoperation was required. Disc height was increased by an average of 25% ( P < .001). The canal area increased from 109 to 149 mm2 ( P < .001) and from 9.3 to 12.2 mm ( P < .001) in anteroposterior diameter. The foramen area demonstrated the effect of indirect decompression on both sides ( P < .001). The height of the foramen showed significant average increase of 2.8 mm ( P < .001). The results from VAS and ODI questionnaires confirmed the clinical effect of indirect decompression. Conclusion: We observed that indirect decompression by the LLIF method is feasible both radiologically and clinically with a low rate of complications and reoperations.

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Change of Lumbar Ligamentum Flavum after Indirect Decompression Using Anterior Lumbar Interbody Fusion

Asian Spine Journal ◽

10.4184/asj.2017.11.1.105 ◽

2017 ◽

Vol 11 (1) ◽

pp. 105-112 ◽

Cited By ~ 11

Author(s):

Seiji Ohtori ◽

Sumihisa Orita ◽

Kazuyo Yamauchi ◽

Yawara Eguchi ◽

Yasuchika Aoki ◽

...

Keyword(s):

Pain Relief ◽

Spinal Canal ◽

Interbody Fusion ◽

Ligamentum Flavum ◽

Case Series ◽

Anterior Fusion ◽

Dural Sac ◽

Canal Diameter ◽

Indirect Decompression

<sec><title>Study Design</title>Retrospective case series.</sec><sec><title>Purpose</title>The purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up.</sec><sec><title>Overview of Literature</title>Extreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported.</sec><sec><title>Methods</title>We evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1–2 to L5–S1 was calculated using a Picture Archiving and Communication System.</sec><sec><title>Results</title>Spinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1–2 to L5–S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4–5 (30 mm2) (fusion level) was significantly less than that at L1–2 to L3–4 or L5–S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4–5 was significantly larger than at the other levels.</sec><sec><title>Conclusions</title>Spinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery.</sec>

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Does the Position of Cage Affect the Clinical Outcome of Lateral Interbody Fusion in Lumbar Spinal Stenosis?

Global Spine Journal ◽

10.1177/2192568220948029 ◽

2020 ◽

pp. 219256822094802

Author(s):

Guangxi Qiao ◽

Min Feng ◽

Jian Liu ◽

Xiaodong Wang ◽

Miao Ge ◽

...

Keyword(s):

Interbody Fusion ◽

Posterior Instrumentation ◽

Stage I ◽

Disc Height ◽

Stage Ii ◽

Disc Space ◽

Posterior Group ◽

Indirect Decompression ◽

Foraminal Height ◽

Segmental Angle

Study Design: A retrospective study. Objective: This study aims to identify the ideal cage position in lateral lumbar interbody fusion (LLIF) and to investigate if the posterior instrumentation would affect the indirect decompression. Methods: Patients underwent 2-stage surgeries: stage I was LLIF and stage II was percutaneous pedicle screws fixation after 1 week. Anterior disc height (ADH), posterior disc height (PDH), left and right foraminal height (FH), and segmental angle (SA) were measured on lateral computed tomography reconstructions. The cross-sectional area of the thecal sac (CSA) was determined by the outlined area of the thecal sac on a T2-weighted axial magnetic resonance imaging. The patients were subgroups according to the cage position: the anterior (cage located at the anterior 1/3 of disc space) and posterior groups (cage located at the posterior 2/3 of disc space). P values <.05 were considered significant. Results: This study included 46 patients and 71 surgical levels. After stage I LLIF, significant increase in ADH, PDH, bilateral FH was found in both 2 subgroups, as well as the CSA (all Ps < .01). SA increased 2.84° ± 3.2° in the anterior group after stage I LLIF and increased 0.81° ± 3.1° in the posterior group ( P = .013). After stage II surgery, SA was similar between the anterior and posterior groups ( P = .20). Conclusion: The anteriorly placed cage may provide better improvement of anterior disc height and segmental angle after stand-alone LLIF surgery. After the second stage posterior instrumentation, the cage position would not affect the segmental angle or foraminal height.

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Minimally Invasive Pedicle Screw Fixation With Indirect Decompression by Ligamentotaxis in Pathological Fractures

Operative Neurosurgery ◽

10.1093/ons/opaa045 ◽

2020 ◽

Vol 19 (2) ◽

pp. 210-217 ◽

Cited By ~ 2

Author(s):

Michael M Safaee ◽

Vinil Shah ◽

Alexander Tenorio ◽

Juan S Uribe ◽

Aaron J Clark

Keyword(s):

Minimally Invasive ◽

Pedicle Screw ◽

Neurological Deficit ◽

Spinal Canal ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Pathological Fractures ◽

Canal Area ◽

Canal Diameter ◽

Indirect Decompression

Abstract BACKGROUND The spine is the most common site of bony metastases. Associated pathological fractures can result in pain, neurological deficit, biomechanical instability, and deformity. OBJECTIVE To present a minimally invasive technique for indirect decompression by ligamentotaxis in pathological fractures. METHODS A minimally invasive approach was utilized to perform percutaneous pedicle screw fixation in patients who required stabilization for pathological fractures. Preoperative and postoperative computed tomography and magnetic resonance imaging were used to compare spinal canal area and midsagittal canal diameter. RESULTS Two patients with newly diagnosed pathological fractures underwent minimally invasive treatment. Each presented with minimal epidural disease and a chief complaint of intractable back pain without neurological deficit. They underwent minimally invasive pedicle screw fixation with indirect decompression by ligamentotaxis. In each case, postoperative imaging demonstrated an increase in spinal canal area and midsagittal canal diameter by an independent neuroradiologist. There were no perioperative complications, and each patient was neurologically stable without evidence of hardware failure at their 5- and 6-mo follow-up visits. CONCLUSION Minimally invasive percutaneous fixation can be used to stabilize pathological fractures and provide indirect decompression by ligamentotaxis. This procedure is associated with minimal blood loss, low morbidity, and rapid initiation of radiation therapy. Only patients with minimal epidural disease, stenosis caused primarily by bony retropulsion, and mild-to-moderate deformity should be considered candidates for this approach.

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Indirect decompression with lateral interbody fusion for severe degenerative lumbar spinal stenosis: minimum 1-year MRI follow-up

Journal of Neurosurgery Spine ◽

10.3171/2020.1.spine191412 ◽

2020 ◽

Vol 33 (1) ◽

pp. 27-34

Author(s):

Takayoshi Shimizu ◽

Shunsuke Fujibayashi ◽

Bungo Otsuki ◽

Koichi Murata ◽

Shuichi Matsuda

Keyword(s):

Interbody Fusion ◽

Disc Height ◽

Decompression Surgery ◽

Posterior Decompression ◽

Canal Stenosis ◽

Indirect Decompression ◽

Lumbar Spinal ◽

Lateral Interbody ◽

Over Time

OBJECTIVEThe use of indirect decompression surgery for severe canal stenosis remains controversial. The purpose of this study was to investigate the efficacy of lateral interbody fusion (LIF) without posterior decompression in degenerative lumbar spinal spondylosis with severe stenosis on preoperative MRI.METHODSThis is a retrospective case series from a single academic institution. The authors included 42 patients (45 surgical levels) who were preoperatively diagnosed with severe degenerative lumbar stenosis on MRI based on the previously published Schizas classification. These patients underwent LIF with supplemental pedicle screw fixation without posterior decompression. Surgical levels were limited to L3–4 and/or L4–5. All patients satisfied the minimum 1-year MRI follow-up. The authors compared the cross-sectional area (CSA) of the thecal sac and the clinical outcome scores (Japanese Orthopaedic Association [JOA] score) preoperatively, immediately postoperatively, and at the 1-year follow-up. Fusion status and disc height were evaluated based on CT scans obtained at the 1-year follow-up.RESULTSThe CSA improved over time, increasing from 54.5 ± 19.2 mm2 preoperatively to 84.7 ± 31.8 mm2 at 3 weeks postoperatively and to 132.6 ± 37.5 mm2 at the last follow-up (average 28.3 months) (p < 0.001). The JOA score significantly improved over time (preoperatively 16.1 ± 4.1, 3 months postoperatively 24.4 ± 4.0, and 1-year follow-up 25.7 ± 2.9; p < 0.001). The fusion rate at the 1-year follow-up was 88.8%, and disc heights were significantly restored (preoperative, 6.3 mm and postoperative, 9.6 mm; p < 0.001). Patients showing poor CSA expansion (< 200% expansion rate) at the last follow-up had a higher prevalence of pseudarthrosis than patients with significant CSA expansion (> 200% expansion rate) (25.0% vs 3.4%, p < 0.001). No major perioperative complications were observed.CONCLUSIONSLIF with indirect decompression for degenerative lumbar disease with severe canal stenosis provided successful clinical outcomes, including restoration of disc height and indirect expansion of the thecal sac. Severe canal stenosis diagnosed on preoperative MRI itself is not a contraindication for indirect decompression surgery.

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Factors Influencing Early Disc Height Loss Following Lateral Lumbar Interbody Fusion

Asian Spine Journal ◽

10.31616/asj.2019.0332 ◽

2020 ◽

Vol 14 (5) ◽

pp. 601-607

Author(s):

Arun-Kumar Kaliya-Perumal ◽

Tamara Lee Ting Soh ◽

Mark Tan ◽

Jacob Yoong-Leong Oh

Keyword(s):

Interbody Fusion ◽

Disc Height ◽

Height Loss ◽

Lumbar Interbody Fusion ◽

Lateral Lumbar Interbody Fusion ◽

Factors Influencing ◽

Cage Subsidence ◽

Indirect Decompression ◽

Height Increase

Study Design: Retrospective radiological analysis.Purpose: To analyze the factors influencing early disc height loss following lateral lumbar interbody fusion (LLIF).Overview of Literature: Postoperative disc height loss can occur naturally as a result of mechanical loading. This phenomenon is enabled by the yielding of the polyaxial screw heads and settling of the cage to the endplates. When coupled with cage subsidence, there can be significant reduction in the foraminal space which ultimately compromises the indirect decompression achieved by LLIF.Methods: Seventy-two cage levels in 37 patients aged 62±10.2 years who underwent single or multilevel LLIF for degenerative spinal conditions were selected. Their preoperative and postoperative follow-up radiographs were used to measure the anterior disc height (ADH), posterior disc height (PDH), mean disc height (MDH), disc space angle (DSA), and segmental angle. Correlations between the loss of disc height and several factors, including age, construct length, preoperative lordosis, postoperative lordosis, disc height, cage dimensions, and cage position, were analyzed.Results: We found that the lateral interbody cages significantly increased ADH, PDH, MDH, and DSA after surgery (p <0.0001). However, there was a loss of disc height over time. All postoperative disc height parameters, especially the amount of increase in MDH (r =0.413, p <0.0001) after surgery, showed a significant positive association with early disc height loss. The levels demonstrating a significant (≥25%) height loss were those that exhibited a substantial height increase (128.3%, 4.6±3.0 to 10.5±5.6 mm) postoperatively. However, the levels that showed less than 25% height loss were those that exhibited, on average, only a 57.4% height increase post-operatively.Conclusions: The greater the postoperative increase in disc height, the greater the disc height loss throughout early follow-up. Therefore, achieving an optimal disc height rather than overcorrection is an important surgical strategy to adopt when performing LLIF.

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Predictors of indirect neural decompression in minimally invasive transpsoas lateral lumbar interbody fusion

Journal of Neurosurgery Spine ◽

10.3171/2020.8.spine20676 ◽

2021 ◽

pp. 1-11

Author(s):

Corey T. Walker ◽

David S. Xu ◽

Tyler S. Cole ◽

Lea M. Alhilali ◽

Jakub Godzik ◽

...

Keyword(s):

Interbody Fusion ◽

Minimum Clinically Important Difference ◽

Central Canal ◽

Disc Height ◽

Leg Pain ◽

Lumbar Interbody Fusion ◽

Predictive Variables ◽

Pain Scores ◽

Clinically Important Difference ◽

Indirect Decompression

OBJECTIVE An advantage of lateral lumbar interbody fusion (LLIF) surgery is the indirect decompression of the neural elements that occurs because of the resulting disc height restoration, spinal realignment, and ligamentotaxis. The degree to which indirect decompression occurs varies; no method exists for effectively predicting which patients will respond. In this study, the authors identify preoperative predictive factors of indirect decompression of the central canal. METHODS The authors performed a retrospective evaluation of prospectively collected consecutive patients at a single institution who were treated with LLIF without direct decompression. Preoperative and postoperative MRI was used to grade central canal stenosis, and 3D volumetric reconstructions were used to measure changes in the central canal area (CCA). Multivariate regression was used to identify predictive variables correlated with radiographic increases in the CCA and clinically successful improvement in visual analog scale (VAS) leg pain scores. RESULTS One hundred seven levels were treated in 73 patients (mean age 68 years). The CCA increased 54% from a mean of 0.96 cm2 to a mean of 1.49 cm2 (p < 0.001). Increases in anterior disc height (74%), posterior disc height (81%), right (25%) and left (22%) foraminal heights, and right (12%) and left (15%) foraminal widths, and reduction of spondylolisthesis (67%) (all p < 0.001) were noted. Multivariate evaluation of predictive variables identified that preoperative spondylolisthesis (p < 0.001), reduced posterior disc height (p = 0.004), and lower body mass index (p = 0.042) were independently associated with radiographic increase in the CCA. Thirty-two patients were treated at a single level and had moderate or severe central stenosis preoperatively. Significant improvements in Oswestry Disability Index and VAS back and leg pain scores were seen in these patients (all p < 0.05). Twenty-five (78%) patients achieved the minimum clinically important difference in VAS leg pain scores, with only 2 (6%) patients requiring direct decompression postoperatively due to persistent symptoms and stenosis. Only increased anterior disc height was predictive of clinical failure to achieve the minimum clinically important difference. CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA, even in patients with substantial central stenosis. Low body mass index, preoperative spondylolisthesis, and disc height collapse appear to be most predictive of successful indirect decompression. Patients with preserved disc height but severe preoperative stenosis are at higher risk of failure to improve clinically.

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