Moderate Lumbar Spinal Stenosis Research Articles

Impact of Racial and Socioeconomic Disparities on Access to Interspinous Spacer for Treatment of Lumbar Spinal Stenosis: A Nationwide Medicare Analysis.

In mild to moderate lumbar spinal stenosis (LSS) where conservative care treatments fail, minimally invasive treatments, such as interspinous spacers without decompression or fusion (ISD), may be appropriate. While previous studies have demonstrated racial and socioeconomic disparities in the surgical treatment of LSS, there are limited data on how those factors impact accessibility to these procedures. This study explored demographic, socioeconomic, and geographic differences in the use of ISD. Using the Medicare 100% files from 2017 through 2022, this retrospective claims analysis identified when and if patients diagnosed with LSS received ISD implantation. Cox proportional hazards regression was used to examine the association between racial and socioeconomic characteristics and the rate of ISD implantation, stratified by geographic region. A total of 1,316,622 individuals met the inclusion criteria; 4730 (0.4%) underwent ISD implantation, with a mean (standard deviation) time to treatment of 11.9 (13.2) months after diagnosis. The likelihood of ISD implantation was higher for older patients (except for the oldest group), males, those with lower disease burden, and White patients. Cox regression revealed that the associations of racial and socioeconomic factors with ISD implantation varied by U.S. region. In the Midwest and Northeast, lower median household income was associated with a decreased likelihood of ISD implantation regardless of race, while in the South, Black patients were less likely to undergo ISD implantation regardless of income. The observed disparities in access to ISD implantation mirror existing trends in surgical interventions for LSS, suggesting further study and interventions are needed to address inequities.

Posterior Lateral Arthrodesis as a Treatment Option for Lumbar Spinal Stenosis: Safety and Early Clinical Outcomes.

Lumbar spinal stenosis (LSS) is a common condition caused by degenerative changes in the lumbar spine with age. LSS is caused by a variety of factors, including degenerative spondylosis and spondylolisthesis. People suffering with LSS experience neurogenic claudication, which causes severe physical limitations, discomfort, and a decrease in quality of life. Less invasive procedures are now being researched to improve the prognosis, success rate, and safety of LSS treatments. Posterior lateral spinal arthrodesis (PLSA) is a new surgical treatment for LSS. This study looks at the procedural and patient safety of PLSA. This study is a multicenter retrospective analysis of the safety of PLSA who met the clinical indications for PLSA and underwent the procedure at eight interventional spine practices. Data was collected on demographical information, pre-procedural numeric rating scale score (NRS), post-procedural NRS, and complication reporting. Patients who were included had LSS with or without spondylolisthesis and had failed conservative treatments. A descriptive statistical analysis was performed to report the outcomes. Results were reported as mean and standard deviations for continuous outcomes, and frequency (%) for categorical outcomes. This retrospective analysis involved 191 patients and 202 PLSA implants. The majority of patients were male Caucasians with a mean age of 69.2 years and a BMI of 31.1. A large majority of implants were placed at the L4-5 level, and the average pre-procedural NRS was 6.3 while the average post-procedural NRS was 3.1, indicating a 50.8% reduction in pain (p < 0.0001). Two patients reported complications, but they were unrelated to the device or surgical procedure; no infections, device malfunctions, or migrations were reported in the patient cohort. Preliminary results with PLSA implants indicate that it is a safe treatment option for patients with moderate LSS who do not respond to conservative management.

ID: 214307 Real-World Incidence of Reoperation Rates With Interspinous Spacers for Lumbar Spinal Stenosis

The use of interspinous spacers, a less invasive treatment option for patients with moderate Lumbar Spinal Stenosis (LSS), has been increasingly adopted over the past few years. Clinical outcomes in a randomized controlled trial with long-term follow-up to 5-years suggested high overall improvement and low reoperation rate with the use of interspinous spacers.1 Here, we report reoperation rates of an ongoing real-world, prospective, multicenter study of patients using an interspinous spacer for LSS.

PO182 / #570 REAL-WORLD, PROSPECTIVE, MULTI-CENTER STUDY OF AN INTERSPINOUS SPACER FOR LUMBAR SPINAL STENOSIS: E-POSTER VIEWING

The introduction of interspinous spacers, a less invasive treatment option for patients with moderate Lumbar Spinal Stenosis (LSS) symptoms has been increasingly adopted over the last several years. Reported clinical outcomes with the use of interspinous spacers suggest high patient satisfaction and overall improvement.1 Here, we report an on-going, prospective, multi-center study of patients using an interspinous spacer for LSS.

PO196 / #782 TREATING MULTIPLE LEVELS OF LUMBAR SPINAL STENOSIS WITH A MINIMALLY-INVASIVE INTERSPINOUS SPACER IMPLANTED USING A SINGLE INCISION: E-POSTER VIEWING

Minimally invasive procedures are increasingly gaining popularity as they result in fewer complications and a quicker recovery. For moderate lumbar spinal stenosis (LSS) patients, interspinous spacers are a minimally invasive option to indirectly decompress and provide symptomatic relief while imparting less trauma to the patient. However, patients with LSS often present with degeneration at multiple contiguous levels, which may have an impact on the initial number of incisions. Here we present evidence on treating multiple LSS levels using a single incision through an observational case-series.

Changes in pain scores and walking distance after epidural steroid injection in patients with lumbar central spinal stenosis.

Lumbar spinal stenosis is a common degenerative disorder that is characterized by pain and neurogenic claudication. Previous studies have evaluated the effects of an epidural steroid injection (ESI) on spinal stenosis, based on changes to the spinal canal diameter.This study aimed to examine the impact of the ESI on pain scores and walking distance in patients with lumbar central spinal stenosis, stratified based on disease severity, which was graded according to the degree of cauda equina separation.We reviewed the medical records of patients who received the ESI for lumbar spinal central canal stenosis. A total of 128 patients were divided into moderate and severe groups, based on the degree of cauda equina separation.Relative to baseline values, 2 weeks after the ESI, the moderate group showed a significant decrease in the numeric rating scale (NRS) scores and an increase in walking distance. Meanwhile, the severe group showed a significant decrease in the NRS scores and no significant change in walking distance. The moderate group had lower NRS scores and a longer walking distance than did the severe group 2 weeks after the ESI. The proportion of patients with improved levels of satisfaction was higher in the moderate group than in the severe group.Lumbar interlaminar ESI may reduce pain scores and increase walking distance in patients with moderate lumbar spinal central canal stenosis. Patients with moderate spinal stenosis achieved better outcomes than did patients with severe stenosis.

Paradigm Shift of Interspinous Device Surgery for Degenerative Lumbar Diseases

Instrumented fusion surgery is an effective surgery for severe degenerative lumbar diseases and can achieve satisfactory clinical outcomes with a high fusion rate. However, due to extensive nature and loss of segmental motion, instrumented fusion can cause complications and adjacent segment disease, and some patients require second surgery. On the contrary, decompression alone is an effective surgery for moderate degenerative lumbar diseases and can achieve satisfactory clinical outcomes. However, failed back surgery syndrome, such as recurrent lumbar disc herniation or spinal stenosis, can occur at the segment of prior surgery, and some patients also require second surgery. In clinical practice, there are indications for instrumented fusion surgery or decompression alone. However, for some cases, it is difficult to decide which surgery is appropriate for the patients; such a situation is called a grey zone (Fig. 1). Instrumented fusion surgery can be excessive, while decompression alone can involve segmental imbalance or problems postoperatively. Interspinous device surgery (ISD) can be considered for grey zone of degenerative lumbar diseases as new solution. According to the traditional concepts, diseased lumbar segment with instability is a cause of low back pain and can require fusion. However, in clinical situations, fusion does not always correlate with successful outcomes. While about 10–20% of solid fusion patients complain of persistent low back pain, some non-union patients do not complain of low back pain. These results lead to questions and uncertainty regarding fusion surgery. First, it is unclear if lumbar instability is a cause of low back pain. Second, it must be determined if fusion surgery is necessary for lumbar instability. Recently, the biomechanical concept of the cause of low back pain has changed. Increased load transmission to facet joints and increased intradiscal pressure to the posterior part of a disc are considered important causes of low back pain. Therefore, spine surgeons view degenerative lumbar diseases differently, resulting in a paradigm shift in surgery of degenerative lumbar diseases. ISD surgery is a dynamic stabilization surgery with an action mechanism of distraction of narrow interspinous space: ISD can widen the spinal canal and neural foramen to achieve indirect decompression of neural structures. In addition, ISD can restore normal lordosis and offset abnormal load shift of facet joints and increased intradiscal pressure to the posterior part of the disc to relieve low back pain. Based on the concept and action mechanism, good indications of ISD surgery are moderate lumbar spinal stenosis (Fig. 2), lumbar disc herniation (Fig. 3), and internal disc derangement (Fig. 4) associated with flexible extension instability or segmental imbalance, such as retrolisthesis or hyperlordosis, which can be reduced in flexion. In contrast, contraindications of ISD surgery are severe lumbar spinal stenosis, flexion instability, degenerative or isthmic spondylolisthesis, rigid extension instability of segmental imbalance that cannot be reduced in flexion, and multilevel degenerative lumbar scoliosis. In our experiences of about 20 years with primary ISD surgery and revision surgery for failures of ISD surgery, the most common cause of failure of ISD surgery is inappropriate indication or patient selection. Another important cause of failure is incorrect surgical technique such as stand-alone use of ISD without decompression, excessive over-distraction (by over-sized ISD), and supraspinous ligament injury or spinous process fracture. These incorrect surgical techniques cause poor surgical outcomes and might require revision surgery. Based on these outcomes, the following advice is offered for successful ISD surgery for degenerative lumbar diseases. First, ISD surgery should be performed for patients with good indications. Second, ISD implantation should be performed after limited decompression including removal of a hypertrophied ligamentum flavum to preserve segmental stability (Fig. 5). In our BMC Musculoskeletal Disorders Publication (Cho et al.) [1], we performed 15-year survivorship analysis of 94 patients with single-level lumbar disc herniation who underwent discectomy and DIAM implantation. We aimed to provide the longest follow-up evidence on the efficacy of DIAM implantation for single-level lumbar disc herniation. The results showed that 8.5% of the patients underwent reoperation at the DIAM implantation level during the 15-year follow-up. The mean time to reoperation was 6.5 years. Kaplan–Meier analysis showed a cumulative survival rate of the DIAM implant of 99% at 1 year, 97% at 5 years, 93% at 10 years, and 92% at 15 years after surgery. Our results showed that DIAM implantation significantly decreased reoperation rate for single-level lumbar disc herniation in 15-year survivorship analysis. This study provides the strongest evidence for the efficacy of DIAM implantation for the treatment of single-level lumbar disc herniation. In our view, this paper, coupled with our previous paper (Sur et al.) [2], settles the debate on the efficacy of DIAM implantation for the treatment of moderate lumbar spinal stenosis or lumbar herniation associated flexible extension instability or segmental imbalance.

Nerve Root Sedimentation Sign: Can It Predict the Success for Surgical Intervention in Patients With Symptomatic Lumbar Spinal Stenosis?

Introduction: The use of interspinous process devices are less invasive surgical methods designed to manage mild to moderate lumbar spinal stenosis symptoms. Symptomatic relief may not be seen in all patients undergoing this procedure. Magnetic resonance imaging (MRI) parameters have been used to predict the success of clinical outcomes in patients with symptomatic lumbar spinal stenosis for decompressive surgeries. The purpose of this study was to determine the feasibility of using nerve root sedimentation sign to predict mid- to long-term clinical outcomes of patients treated with interspinous spacers for lumbar spinal stenosis.Methods: This was a retrospective study using prospective multicenter Food and Drug Administration Investigational Device Exemption (FDA IDE) trial (Superion™ and X-STOP®) data. Inclusion criteria were patients treated with interspinous spacers, aged 45 or older with lumbar spinal stenosis at one or more contiguous levels from L1 to L5 and symptoms of neurogenic claudication. Preoperative axial T2 weighted MRI images were used to determine nerve root sedimentation sign. Preoperative, six-week, one- and two-year postoperative clinical outcomes were measured using Oswestry Disability Index (ODI) scores. Clinical outcomes were compared between positive and negative nerve root sedimentation sign groups; p ≤0.05 was considered significant.Results: This study included n=374 patients; 40 excluded; 334 included (113=positive nerve root sedimentation sign (NRSS) (34%) and 221=negative NRSS (66%)). At six weeks, significant postoperative ODI correction was noted in both groups (p<0.001). No significant differences in ODI scores were identified between groups. A subgroup analysis with MRI image quality grade 3 and certainty determination grade 5, six-week postoperative ODI correction was significant in both groups. Six-week, one- and two-year postoperative ODI scores were greater by 6 points in the positive nerve root sedimentation sign group compared to the negative nerve root sedimentation sign group.Conclusions: Although satisfactory postoperative improvement occurred in both groups, there were statistically significant differences noted in certain sub-categories. The subgroup analysis indicated MRI image quality and nerve root sedimentation sign certainty of determination may be factors that may aid with planning the surgical management of lumbar spinal stenosis.

Percutaneous Pedicle-Lengthening Osteotomy in Minimal Invasive Spinal Surgery to Treat Degenerative Lumbar Spinal Stenosis: A Single-Center Preliminary Experience.

Lumbar spinal stenosis (LSS) is a narrowing of the spinal canal due to spinal degeneration, and its main clinical symptom is neurogenic claudication. Surgical treatment is pursued for patients who do not improve with conservative care. Patients with symptomatic LSS who also have significant medical comorbidities, although clearly in need of intervention, are unattractive candidates for traditional open lumbar decompressive procedures. Thus it is important to explore minimally invasive surgical techniques to treat select patients with LSS. This retrospective case series evaluated the clinical and radiographic outcomes of a new minimally invasive procedure to treat LSS: pedicle-lengthening osteotomy using the ALTUM system ((Innovative Surgical Designs, Inc., Bloomington, Indiana, United States). Peri- and postoperative demographic and radiographic data were collected from a clinical series of seven patients with moderate LSS who were > 60 years of age. Clinical outcome was evaluated using visual analog scale (VAS) scores and the spinal canal area on computed tomography scans. Twelve months after the procedure, scoring revealed a median improvement of 3.7 on the VAS for the back and 6.3 on the VAS for the leg, compared with the preoperative baseline (p < 0.05). The postoperative central area of the lumbar canal was significantly increased, by 0.39 cm2; the right and left neural foramina were enlarged by 0.29 cm2 and 0.47 cm2, respectively (p < 0.05). In this preliminary study, the ALTUM system showed a good clinical and radiologic outcome 1 year after surgery. In an older or high-risk population, a short minimally invasive procedure may be beneficial for treating LSS.

P200 - Four-Year Results of a Randomized Controlled Trial for Treatment of Moderate Lumbar Spinal Stenosis with InterSpinous Spacer

BACKGROUND CONTEXT: Lumbar spinal stenosis (LSS) is the most common diagnosis for spinal surgery in patients over 55 years of age. Previously, the only surgical option available to patients with moderate LSS unresponsive to conservative care was to undergo a laminectomy with or without fusion. Now there is a minimally invasive surgical option.

Superion Interspinous Spacer Treatment of Moderate Spinal Stenosis: 4-Year Results.

To determine 4-year clinical outcomes in patients with moderate lumbar spinal stenosis treated with minimally invasive stand-alone interspinous process decompression using the Superion device. The 4-year Superion data were extracted from a randomized, controlled Food and Drug Administration investigational device exemption trial. Patients with intermittent neurogenic claudication relieved with back flexion who failed at least 6 months of nonsurgical management were enrolled. Outcomes included Zurich Claudication Questionnaire (ZCQ) symptom severity (ss), physical function (pf) and patient satisfaction (ps) subdomains, leg and back pain visual analog scale (VAS), and Oswestry Disability Index (ODI). At 4-year follow-up, 89 of the 122 patients (73%) provided complete clinical outcome evaluations. At 4 years after index procedure, 75 of 89 patients with Superion (84.3%) demonstrated clinical success on at least 2 of 3 ZCQ domains. Individual component responder rates were 83% (74/89), 79% (70/89), and 87% (77/89) for ZCQss, ZCQpf, and ZCQps; 78% (67/86) and 66% (57/86) for leg and back pain VAS; and 62% (55/89) for ODI. Patients with Superion also demonstrated percentage improvements over baseline of 41%, 40%, 73%, 69%, and 61% for ZCQss, ZCQpf, leg pain VAS, back pain VAS, and ODI. Within-group effect sizes all were classified as very large (>1.0): 1.49, 1.65, 1.42, 1.12, and 1.46 for ZCQss, ZCQpf, leg pain VAS, back pain VAS, and ODI. Minimally invasive implantation of the Superion device provides long-term, durable relief of symptoms of intermittent neurogenic claudication for patients with moderate lumbar spinal stenosis.

Superion interspinous process spacer for intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis: two-year results from a randomized controlled FDA-IDE pivotal trial.

Prospective, multicenter, randomized, controlled, investigational device exemption noninferiority trial. To determine 2-year outcomes in patients with intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis (LSS) who were treated with the Superion interspinous process spacer. Interspinous spacers are a less-invasive treatment alternative compared with surgical decompression for patients with LSS unresponsive to conservative care. High-quality comparative data with these devices are lacking. Patients presenting with intermittent neurogenic claudication secondary to moderate LSS who failed at least 6 months of nonsurgical management were randomly allocated to treatment with the Superion spacer or a control spacer (X-Stop) and followed for 2 years. A total of 391 randomized patients were implanted with Superion (n = 190) or control (n = 201) spacers at 29 sites in the United States between August 2008 and December 2011. Implants were successfully implanted in 99.5% of patients with Superion and 99.0% of control patients. The primary composite endpoint of this study was met, which demonstrated that the Superion spacer was noninferior to the X-Stop spacer. Leg pain, the predominant patient complaint, decreased in severity by 70% during 2 years in each group. Most (77%) patients achieved leg pain clinical success (improvement ≥20 mm) at 2 years. Back pain clinical success (improvement ≥20 mm) was 68%, with no differences between groups. Oswestry Disability Index clinical success (≥15% point improvement) was achieved in 65% of patients. The rates of complications and reoperations were similar between groups. The Superion interspinous process spacer relieves symptoms of intermittent neurogenic claudication secondary to moderate LSS in the majority of patients through 2 years. 2.

Poster 466 Two-year Outcomes of a Prospective Randomized Controlled Trial of Interspinous Spacer Treatment for Moderate Lumbar Spinal Stenosis

Poster 466 Two-year Outcomes of a Prospective Randomized Controlled Trial of Interspinous Spacer Treatment for Moderate Lumbar Spinal Stenosis

Treatment of the Moderate Lumbar Spinal Stenosis with an Intespinous Distraction Device IMPALA

Introduction: The aim of this study was the evaluation of symptom improvements in patients with moderate lumbar spinal stenosis, who consecutively underwent placement of interspinous distraction deviceIMPALA®.Methods: This study included a total of 11 adult patients with moderate lumbar spinal stenosis. Clinical evaluations were performed preoperatively and 3-months after surgery using the Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI).Results: The mean preoperative VAS was 7.09 and fell to 2.27 a 3-months after surgery. The mean preoperative ODI was 59.45 fell to 20.72 a 3-months after surgery.Conclusions: Using the IMPALA® device in patients with moderate lumbar spinal stenosis is a minimal invasive, effective and safe procedure. Clinical symptoms were improved 3 months after surgery.

Mid-term Outcomes of a Prospective Randomized Controlled Trial of Interspinous Spacer Treatment for Moderate Lumbar Spinal Stenosis

Mid-term Outcomes of a Prospective Randomized Controlled Trial of Interspinous Spacer Treatment for Moderate Lumbar Spinal Stenosis

Midterm Outcomes of a Prospective Multicenter Randomized Controlled Trial Comparing the Clinical Efficacy of Interspinous Spacers as a Treatment for Moderate Lumbar Spinal Stenosis

Midterm Outcomes of a Prospective Multicenter Randomized Controlled Trial Comparing the Clinical Efficacy of Interspinous Spacers as a Treatment for Moderate Lumbar Spinal Stenosis

Interspinous Spacer Implant in Patients with Lumbar Spinal Stenosis: Preliminary Results of a Multicenter, Randomized, Controlled Trial

A prospective, randomized, controlled trial was conducted to compare clinical outcomes in patients treated with an investigational interspinous spacer (Superion) versus those treated with an FDA-approved spacer (X-STOP). One hundred sixty-six patients with moderate lumbar spinal stenosis (LSS) unresponsive to conservative care were treated randomly with the Superion (n = 80) or X-STOP (n = 86) interspinous spacer. Study subjects were followed through 6 months posttreatment. Zurich Claudication Questionnaire (ZCQ) symptom severity scores improved 30% with Superion and 25% with X-STOP (both P < 0.001). Similar changes were noted in ZCQ physical function with improvements of 32% with Superion and 27% with X-STOP (both P < 0.001). Mean ZCQ patient satisfaction score ranged from 1.7 to 2.0 in both groups at all follow-up visits. The proportion of subjects that achieved at least two of three ZCQ clinical success criteria at 6 months was 75% with Superion and 67% with X-STOP. Axial pain decreased from 55 ± 27 mm at pretreatment to 22 ± 26 mm at 6 months in the Superion group (P < 0.001) and from 54 ± 29 mm to 32 ± 31 mm with X-STOP (P < 0.001). Extremity pain decreased from 61 ± 26 mm at pretreatment to 18 ± 27 mm at 6 months in the Superion group (P < 0.001) and from 64 ± 26 mm to 22 ± 30 mm with X-STOP (P < 0.001). Back function improved from 38 ± 13% to 21 ± 19% with Superion (P < 0.001) and from 40 ± 13% to 25 ± 16% with X-STOP (P < 0.001). Preliminary results suggest that the Superion interspinous spacer and the X-STOP each effectively alleviate pain and improve back function in patients with moderate LSS who are unresponsive to conservative care.

Minimally Invasive Treatment of Moderate Lumbar Spinal Stenosis with the Superion® Interspinous Spacer

Purpose:We evaluated the safety and effectiveness of the minimally invasive Superion® Interspinous Spacer (VertiFlex, Inc., San Clemente, CA) in patients with moderate LSS.Methods:This single-arm prospective study enrolled 121 patients with moderate LSS between February 2008 and August 2009 and were followed up at 1 (n=111), 3 (n=96), 6 (n=81), and 12 (n=52) months. All patients were treated with the Superion Interspinous Spacer. Main outcomes were back function with the Oswestry Disability Index (ODI), extremity and axial pain severity with an 11-point scale, health-related quality of life with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-36, and adverse events through 12 months.Results:ODI improved 64% (p<0.001) through 12 months and clinical success was 92%. Extremity and axial pain improved 53% and 49% (both p<0.001), respectively, through 12 months with clinical success of 76% for axial pain and 86% for extremity pain. Health-related quality of life improved 41% for PCS and 22% for MCS (both p<0.001) through 12 months. PCS clinical success was 81% and MCS clinical success was 62% at 12 months. Four (5.9%) explants were performed although 3 were unrelated to the device. Eight procedure-related adverse events, observed in 6 (5.0%) patients, included superficial incision seroma (n=5), minor wound pain (n=2), and infection (n=1).Conclusions:Preliminary results with the Superion Interspinous Spacer suggest that it is an effective and safe treatment option for patients with moderate LSS who are unresponsive to conservative care.

Long-term results of surgery for lumbar spinal stenosis: a randomised controlled trial

We randomised a total of 94 patients with long-standing moderate lumbar spinal stenosis (LSS) into a surgical group and a non-operative group, with 50 and 44 patients, respectively. The operative treatment comprised undercutting laminectomy of stenotic segments, augmented with transpedicular-instrumented fusion in suspected lumbar instability. The primary outcome was the Oswestry disability index (ODI), and the other main outcomes included assessments of leg and back pain and self-reported walking ability, all based on questionnaire data from 85 patients at the 6-year follow-up. At the 6-year follow-up, the mean difference in ODI in favour of surgery was 9.5 (95% confidence interval 0.9-18.1, P-value for global difference 0.006), whereas the intensity of leg or back pain did not differ between the two treatment groups any longer. Walking ability did not differ between the treatment groups at any time. Decompressive surgery of LSS provided modest but consistent improvement in functional ability, surpassing that obtained after non-operative measures.

Minimally invasive treatment of lumbar spinal stenosis with a novel interspinous spacer

PurposeTo assess the safety and effectiveness of a novel, minimally invasive interspinous spacer in patients with moderate lumbar spinal stenosis (LSS).MethodsA total of 53 patients (mean age, 70 ± 11 years; 45% female) with intermittent neurogenic claudication secondary to moderate LSS, confirmed on imaging studies, were treated with the Superion® Interspinous Spacer (VertiFlex, Inc, San Clemente, CA) and returned for follow-up visits at 6 weeks, 1 year, and 2 years. Study endpoints included axial and extremity pain severity with an 11-point numeric scale, Zurich Claudication Questionnaire (ZCQ), back function with the Oswestry Disability Index (ODI), health-related quality of life with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-12, and adverse events.ResultsAxial and extremity pain each decreased 54% (both P < 0.001) over the 2-year follow-up period. ZCQ symptom severity scores improved 43% (P < 0.001) and ZCQ physical function improved 44% (P < 0.001) from pre-treatment to 2 years post-treatment. A statistically significant 50% improvement (P < 0.001) also was noted in back function. PCS and MCS each improved 40% (both P < 0.001) from pre-treatment to 2 years. Clinical success rates at 2 years were 83%–89% for ZCQ subscores, 75% for ODI, 78% for PCS, and 80% for MCS. No device infection, implant breakage, migration, or pull-out was observed, although two (3.8%) patients underwent explant with subsequent laminectomy.ConclusionModerate LSS can be effectively treated with a minimally invasive interspinous spacer. This device is appropriate for select patients who have failed nonoperative treatment measures for LSS and meet strict anatomical criteria.