Lumbar Spinal Stenosis and Degenerative Spondylolisthesis: A Review of the SPORT Literature

The relationship between paraspinal muscle atrophy and degenerative lumbar spondylolisthesis at the L4/5 level

BACKGROUND/CONTEXT

Degenerative lumbar spondylolisthesis (DLS) is a prevalent spinal condition that can result in significant disability. DLS is thought to result from a combination of disc and facet joint degeneration, as well as various biological, biomechanical, and behavioral factors. One hypothesis is the progressive degeneration of segmental stabilizers, notably the paraspinal muscles, contributes to a vicious cycle of increasing slippage.

PURPOSE

To examine the correlation between paraspinal muscle status on MRI and severity of slippage in patients with symptomatic DLS.

STUDY DESIGN/SETTING

Retrospective cross-sectional study at an academic tertiary care center.

PATIENT SAMPLE

Patients who underwent surgery for DLS at the L4/5 level between 2016-2018 were included. Those with multilevel DLS or insufficient imaging were excluded.

OUTCOME MEASURES

The percentage of relative slippage (RS) at the L4/5 level evaluated on standing lateral radiographs. Muscle morphology measurements including functional cross-sectional area (fCSA), body height normalized functional cross-sectional area (HI) of Psoas, erector spinae (ES) and multifidus muscle (MF) and fatty infiltration (FI) of ES and MF were measured on axial MR. Disc degeneration and facet joint arthritis were classified according to Pfirrmann and Weishaupt, respectively.

METHODS

Descriptive and comparative statistics, univariable and multivariable linear regression models were utilized to examine the associations between RS and muscle parameters, adjusting for confounders sex, age, BMI, segmental degeneration, and back pain severity and symptom duration.

RESULTS

The study analyzed 138 out of 183 patients screened for eligibility. The median age of all patients was 69.5 years (IQR 62 to 73), average BMI was 29.1 (SD±5.1) and average preoperative ODI was 46.4 (SD±16.3). Patients with Meyerding-Grade 2 (M2, N=25) exhibited higher Pfirrmann scores, lower MFfCSA and MFHI, and lower BMI, but significantly more fatty infiltration in the MF and ES muscles compared to those with Meyerding Grade 1 (M1). Univariable linear regression showed that each cm2 decrease in MFfCSA was associated with a 0.9%-point increase in RS (95% CI -1.4 to - 0.4, p<.001), and each cm2/m2 decrease in MFHI was associated with an increase in slippage by 2.2%-points (95% CI -3.7 to -0.7, p=.004). Each 1%-point rise in ESFI and MFFI corresponded to 0.17%- (95% CI 0.05-0.3, p=.01) and 0.20%-point (95% CI 0.1-0.3 p<.001) increases in relative slippage, respectively. Notably, after adjusting for confounders, each cm2 increase in PsoasfCSA and cm2/m2 in PsoasHI was associated with an increase in relative slippage by 0.3% (95% CI 0.1-0.6, p=.004) and 1.1%-points (95% CI 0.4-1.7, p=.001). While MFfCSA tended to be negatively associated with slippage, this did not reach statistical significance (p=.105). However, each 1%-point increase in MFFI and ESFI corresponded to increases of 0.15% points (95% CI 0.05-0.24, p=.002) and 0.14% points (95% CI 0.01-0.27, p=.03) in relative slippage, respectively.

CONCLUSION

This study found a significant association between paraspinal muscle status and severity of slippage in DLS. Whereas higher degeneration of the ES and MF correlate with a higher degree of slippage, the opposite was found for the psoas. These findings suggest that progressive muscular imbalance between posterior and anterior paraspinal muscles could contribute to the progression of slippage in DLS.

Degenerative lumbar spondylolisthesis: review of current classifications and proposal of a novel classification system

PURPOSE

To review existing classification systems for degenerative spondylolisthesis (DS), propose a novel classification designed to better address clinically relevant radiographic and clinical features of disease, and determine the inter- and intraobserver reliability of this new system for classifying DS.

METHODS

The proposed classification system includes four components: 1) segmental dynamic instability, 2) location of spinal stenosis, 3) sagittal alignment, and 4) primary clinical presentation. To establish the reliability of this system, 12 observers graded 10 premarked test cases twice each. Kappa values were calculated to assess the inter- and intraobserver reliability for each of the four components separately.

RESULTS

Interobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation was 0.94, 0.80, 0.87, and 1.00, respectively. Intraobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation were 0.91, 0.88, 0.87, and 0.97, respectively.

CONCLUSION

The UCSF DS classification system provides a novel framework for assessing DS based on radiographic and clinical parameters with established implications for surgical treatment. The almost perfect interobserver and intraobserver reliability observed for all components of this system demonstrates that it is simple and easy to use. In clinical practice, this classification may allow subclassification of similar patients into groups that may benefit from distinct treatment strategies, leading to the development of algorithms to help guide selection of an optimal surgical approach. Future work will focus on the clinical validation of this system, with the goal of providing for more evidence-based, standardized approaches to treatment and improved outcomes for patients with DS.

Projections From Surgical Use Models in Germany Suggest a Rising Number of Spinal Fusions in Patients 75 Years and Older Will Challenge Healthcare Systems Worldwide

BACKGROUND

Spinal fusion is a well-established procedure in the treatment of degenerative spinal diseases. Previous research shows that the use of this operative treatment has been growing in recent decades in industrialized countries and has become one of the most cost-intensive surgical procedures. It seems that in some countries such as Germany-with its large, industrialized, European population-this increase is mainly driven by demographic changes with low fertility rates, increasing life expectancy, and an aging population. Based on current projections, however, Germany faces a population trend that many other countries are likely to follow within a few decades. An increasingly shrinking and aging working population may eventually put the healthcare system under enormous pressure, with greater demands for spinal fusions and associated higher costs. Thus, we aimed to provide reliable projections regarding the future demand for posterior spinal fusion procedures including age- and gender-related trends up to 2060, which will be necessary for future resource planning and possible improvements in actual treatment strategies.

QUESTIONS/PURPOSES

(1) How is the use of posterior spinal fusions in Germany expected to change from 2019 through 2060, if currents trends continue? (2) How is the use of posterior spinal fusions in Germany expected to change depending on patients' age and gender during this time period?

METHODS

Comprehensive nationwide data provided by the Federal Statistical Office, the official institution for documenting all data on operations and procedures performed in Germany, were used to quantify posterior spinal fusion rates as a function of calendar year, age, and gender. Because there is a lack of evidence regarding future trends in the use of posterior spinal fusions, an autoregressive integrated moving average model on historical procedure rates from 2005 to 2019 in relation to official population projections from 2020 to 2060 was chosen to forecast future absolute numbers and incidence rates of this procedure in Germany. Long-term forecasting is more prone to unexpected disruptions than forecasting over short-term periods; however, longer spans facilitate estimates of how trends may challenge future healthcare systems if those trends continue, and thus are useful for research and planning.

RESULTS

The incidence rate of posterior spinal fusion was projected to increase by approximately 83% (95% CI 28% to 139%) to 102% per 100,000 inhabitants (95% CI 71% to 133%) in 2060, with a 1.3-fold higher rate of women undergoing surgery in terms of absolute numbers. The highest increase identified by the model occurred in patients 75 years and older with 38,974 (95% CI 27,294 to 50,653) posterior spinal fusions in 2060, compared with 14,657 in 2019. This trend applied for both women and men, with a 246% (95% CI 138% to 355%) increase in the total number of posterior spinal fusions for women 75 years and older and a 296% (95% CI 222% to 370%) increase for men 75 years and older. At the same time, posterior spinal fusions in all age groups younger than 55 years were projected to follow a constant or even negative trend up to 2060.

CONCLUSION

Our findings suggest that increasing use of posterior spinal fusion, particularly in patients 75 years and older, will challenge healthcare systems worldwide if current trends persist. This study may serve as a model for many other industrialized countries facing similar demographic and procedure-specific developments in the future. This emphasizes the need to focus on frailty research as well as appropriate financial and human resource management. Effective perioperative medical management, multidisciplinary treatment, and interinstitutional protocols are warranted, especially in older patients as we attempt to manage these trends in the future.

LEVEL OF EVIDENCE

Level III, economic and decision analysis.

Instrumented Versus Noninstrumented Spinal Fusion for Degenerative Lumbar Spondylolisthesis: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

This systematic review compares radiographic and clinical outcomes between instrumented and noninstrumented posterolateral lumbar spine fusions for the treatment of degenerative lumbar spondylolisthesis.

SUMMARY OF BACKGROUND DATA

The optimal method of fusion for instability from degenerative lumbar spondylolisthesis remains to be an area of debate amongst spine surgeons. There are no prior comprehensive systematic review of comparative studies that compares outcomes between instrumented and noninstrumented posterolateral spine fusions for the treatment of degenerative lumbar spondylolisthesis.

MATERIALS AND METHODS

A systematic review was registered with PROSPERO and performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using the PubMed, SCOPUS, and Ovid MEDLINE databases. All level I-III comparative studies published in the English language investigating the clinical outcomes between instrumented and noninstrumented posterolateral spine fusions for the treatment of degenerative lumbar spondylolisthesis were included.

RESULTS

Seven studies (672 patients, 274 noninstrumented, 398 instrumented) were analyzed. One randomized study was level I evidence, 2 randomized studies were level II, and 4 nonrandomized studies were level III. Mean follow-up ranged from 1.4 to 5.9 years. Instrumented patients had a higher rate of solid fusion (87.6% vs. 77.1%, P=0.023) and a lower rate of definitive pseudarthrosis (5.3% vs. 19.9%, P<0.001). However, there was no difference in overall functional improvement at final follow-up between the 2 treatment groups (75.0% vs. 81.7%, P=0.258). In addition, there was no difference in reoperation or complication rates.

CONCLUSIONS

For the treatment of degenerative lumbar spondylolisthesis, there are significantly higher rates of fusion among patients undergoing instrumented posterolateral fusion compared with noninstrumented posterolateral fusion. However, there is no difference in overall functional improvement, pain-related outcome scores, reoperation rates, or complication rates between the 2 treatment groups.

LEVEL OF EVIDENCE

Level III-systematic review of level I-III studies.

Surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia for treating elderly patients with lumbar central canal stenosis

OBJECTIVE

Surgical decompression via a posterior interlaminar approach is widely used for treating lumbar central canal stenosis (LCCS). However, this surgical approach poses a challenge for elderly patients with comorbidities. Thus, the authors tried a new surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia to treat such patients. The aim of this study was to evaluate the safety and effectiveness of surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia for patients with LCCS.

METHODS

Patients with LCCS who underwent surgical decompression, performed by a single surgeon, between January 2016 and March 2019 were retrospectively analyzed. All patients received decompression via the unilateral intervertebral foraminal approach with local anesthesia. Visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, modified Macnab criteria, walking distance, and Schizas classification were used as outcome predictors. Additionally, a decompression evaluation method was designed for use after spinal endoscopic surgery.

RESULTS

Overall, 23 patients with a mean age of 69 years were included in this study, with a mean follow-up of 28 months. Low-back and leg pain were significantly improved after decompression surgery. Postoperative ODI scores and walking distances were statistically significantly better than before surgery. Postoperatively, the Schizas classification for all patients was improved by at least 1 grade compared with the preoperative grade. No complications occurred during the follow-up period. According to the novel decompression evaluation method, all patients had at least achieved decompression in part 123+B.

CONCLUSIONS

Surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia showed promising outcomes in the treatment of elderly patients with LCCS. Additionally, a proposed postoperative decompression evaluation method can help guide surgical decompression.

Decompression Using Minimally Invasive Surgery for Lumbar Spinal Stenosis Associated with Degenerative Spondylolisthesis: A Review

Lumbar spinal stenosis (LSS), which often occurs concurrently with degenerative spondylolisthesis (DS), is a common disease in the elderly population, affecting the quality of life of aged people significantly. Notwithstanding the frequently good effect of conservative therapy on LSS, a minority of the patients ultimately require surgery. Surgery for LSS aims to decompress the narrowed spinal canals with preservation of spinal stability. Traditional open surgery, either pure decompression or decompression with fusion, was considered effective for the treatment of LSS with or without DS. However, the long-term clinical outcomes of traditional open surgery are still unclear. Moreover, the disadvantages of conventional open surgery are extensive, examples including tissue injuries or secondary instability, with limited outcomes and significant reoperation rates. With the development and improvement of surgical tools, various minimally invasive spine surgery (MISS) methods, including indirect decompression techniques of interspinous process devices (IPDs) and direct decompression techniques such as microscopic spine surgery or endoscopic spine surgery (ESS), have been updated with enhancement. IPDs, such as Superion devices, were reported to behave with comparable physical function, disability, and symptoms outcomes to laminectomy decompression. As an emerging technique of MISS, ESS has beneficial hallmarks including minimal tissue injuries, reduced complication rates, and shortened recovery periods, thus gaining popularity in recent years. ESS can be classified in terms of endoscopic hallmarks and approaches. Predictably, with the continuous development and gradual maturity, MISS is expected to replace traditional open surgery widely in the surgical treatment of LSS associated with DS in the future.

Impact of Concomitant Spinal Canal Stenosis on Clinical Presentation of Adult Onset Degenerative Lumbar Spondylolisthesis: A Study Combining Clinical and Imaging Spectrum

Aim Degenerative lumbar spondylolisthesis (DSL) is one of the reasons behind adult-onset backache due to degenerative spinal pathology. Clinical manifestations of this can range from asymptomatic patients to widely variable clinical signs and symptoms. Spinal canal stenosis (SCS) is the most common associated degenerative condition in the MRI of DSL. Moreover, other associated degenerative conditions may contribute significantly towards the clinical presentation. We have tried to assess the impact of SCS on the clinical symptomatology and presentation of the DSL by correlating the clinical and imaging findings. Methods This single-center prospective observational study has analysed 48 patients who were symptomatic due to DSL. The data was collected over a period of 18 months from January 2015 to June 2016 by screening through the adult patients presenting at the orthopaedic or spinal clinics with features suggestive of degenerative lumbar spine disease. Particular inclusion and exclusion criteria were developed as a screening tool and selected patients underwent imaging investigations. Patients had lumbar spine radiographs, both standing and flexion-extension view, and MRI of the lumbar spine. The presenting clinical features were documented. Their clinical and neurological assessment was done thoroughly by two qualified clinicians independently. Results The study population included 29 female (60.5%) and 19 male (39.5%) patients. The mean age of the study population was 49.5 years (SD 9.2 years). As per the radiological diagnostic criteria, 28 patients (58.3%) had features of SCS together with DSL and the rest of the 20 patients (41.7%) had DSL without SCS. Axial back pain and claudication had a statistically significant association with imaging findings. Similarly, patients with associated canal stenosis had statistically significant sensory and motor deficits, altered deep tendon reflexes. Facet joint angle more than 45 degrees at the level of the slip had a higher incidence of indicative presenting symptoms. However, this was not statistically proven. Conclusion DSL is a heterogeneous condition with the simultaneous presence of different degenerative processes in the lumbar spine at various stages. Hence, clinical presentations are widely variable. The concomitant presence of SCS significantly influences the clinical symptomatology with correlation to the MRI findings. Therefore, a judicious weighing of the clinical and imaging findings is crucial for prudent management planning for cases of DSL.

Non-Surgical Interventions for Lumbar Spinal Stenosis Leading To Neurogenic Claudication: A Clinical Practice Guideline

Lumbar spinal stenosis (LSS) causing neurogenic claudication (NC) is increasingly common with an aging population and can be associated with significant symptoms and functional limitations. We developed this guideline to present the evidence and provide clinical recommendations on nonsurgical management of patients with LSS causing NC. Using the GRADE approach, a multidisciplinary guidelines panel based recommendations on evidence from a systematic review of randomized controlled trials and systematic reviews published through June 2019, or expert consensus. The literature monitored up to October 2020. Clinical outcomes evaluated included pain, disability, quality of life, and walking capacity. The target audience for this guideline includes all clinicians, and the target patient population includes adults with LSS (congenital and/or acquired, lateral recess or central canal, with or without low back pain, with or without spondylolisthesis) causing NC. The guidelines panel developed 6 recommendations based on randomized controlled trials and 5 others based on professional consensus, summarized in 3 overarching recommendations: (Grade: statements are all conditional/weak recommendations) Recommendation 1. For patients with LSS causing NC, clinicians and patients may initially select multimodal care nonpharmacological therapies with education, advice and lifestyle changes, behavioral change techniques in conjunction with home exercise, manual therapy, and/or rehabilitation (moderate-quality evidence), traditional acupuncture on a trial basis (very low-quality evidence), and postoperative rehabilitation (supervised program of exercises and/or educational materials encouraging activity) with cognitive-behavioral therapy 12 weeks postsurgery (low-quality evidence). Recommendation 2. In patients LSS causing NC, clinicians and patients may consider a trial of serotonin-norepinephrine reuptake inhibitors or tricyclic antidepressants. (very low-quality evidence). Recommendation 3. For patients LSS causing NC, we recommend against the use of the following pharmacological therapies: nonsteroidal anti-inflammatory drugs, methylcobalamin, calcitonin, paracetamol, opioids, muscle relaxants, pregabalin (consensus-based), gabapentin (very low-quality), and epidural steroidal injections (high-quality evidence). PERSPECTIVE: This guideline, on the basis of a systematic review of the evidence on the nonsurgical management of lumbar spine stenosis, provides recommendations developed by a multidisciplinary expert panel. Safe and effective non-surgical management of lumbar spine stenosis should be on the basis of a plan of care tailored to the individual and the type of treatment involved, and multimodal care is recommended in most situations.

Different Types of Double-Level Degenerative Lumber Spondylolisthesis: What Is Different in the Sagittal Plane?

BACKGROUND

Degenerative lumber spondylolisthesis (DLS) is a common orthopedic condition, described as a condition that compared with the lower vertebra, the superior vertebra slides forward or backward in the sagittal plane without accompanying isthmic spondylolisthesis. Information pertaining to different types of double-level DLS is scarce. This study aims to analyze parameters of patients with different types of double-level DLS to provide a reference for guiding surgical treatment and restoring sagittal balance of patients with DLS.

METHODS

From January 2014 to January 2020, records of patients with double-level DLS were retrospectively reviewed. Patients with double-level DLS were divided into 3 types: anterior, posterior, and combined; the anterior and combined types were studied. The sagittal spinopelvic parameters included C7 tilt, maximal thoracic kyphosis, maximal lumbar lordosis (LLmax), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). After descriptive analysis, demographic and radiographic data were compared.

RESULTS

Forty and 18 patients were included in the anterior and combined type groups, respectively. Both groups had different levels of chronic low back pain, but the incidence of radiating leg pain and neurogenic claudication was significantly higher in the anterior type. Oswestry Disability Index and visual analog scale low back scores were also higher in the anterior type. In the anterior type, C7 tilt (7.14 ± 2.15 vs. 5.41 ± 2.28, P = 0.007), LLmax (50.02 ± 14.76 vs. 36.96 ± 14.56, P = 0.003), PI (68.28 ± 9.16 vs. 55.53 ± 14.19, P < 0.001), PT (28.68 ± 7.31 vs. 19.38 ± 4.70, P < 0.001), and PT/PI (42.45 ± 11.22 vs. 36.04 ± 9.87, P = 0.041) were significantly higher. In the anterior type, PI correlated positively with LLmax (r = 0.59) and SS (r = 0.71). LLmax and SS (r = 0.65) had a positive correlation. PT/PI and SS (r = -0.77) had a negative correlation. In the combined type, PI correlated positively with LLmax (r = 0.61) and SS (r = 0.88), and PT/PI correlated negatively with SS (r = -0.81).

CONCLUSIONS

In patients with double-level DLS, the sagittal spinopelvic parameters differed between the anterior and combined types. Overall, spinal surgeons should focus on correcting sagittal deformities, relieving postoperative clinical symptoms, and improving quality of life during fusion surgery.

MIS-TLIF versus O-TLIF for single-level degenerative stenosis: study protocol for randomised controlled trial

INTRODUCTION

Patients with symptomatic single-level combination of degenerative stenosis and low-grade spondylolisthesis are often treated by nerve root decompression and spinal fusion. The gold standard is traditional open decompression and fusion, but minimally invasive method is more and more prevailing. However, there is lack of high-quality studies comparing these two techniques in order to obtain the advantages and certain indications to use one of these methods. The current study includes clinical, safety and radiological endpoints to determine the effectiveness of minimally invasive decompression and fusion (MIS-TLIF) over the traditional open one (O-TLIF).

METHODS AND ANALYSIS

All patients aged 40-75 years with neurogenic claudication or bilateral radiculopathy caused by single-level combination of degenerative stenosis and low-grade spondylolisthesis, confirmed by MRI with these symptoms persisting for at least 3 months prior to surgery, are eligible. Patients will be randomised into MIS-TLIF or traditional O-TLIF. The primary outcome measure is Oswestry Disability Index at 3-month follow-up term. The secondary outcomes are patient-reported outcome measures by the number of clinical scales, radiological parameters including sagittal balance parameters, safety endpoints and cost-effectiveness of each method. All patients will be analysed preoperatively, as well as on the 14th day of hospital stay (or on the day of hospital discharge), 3 months, 6 months, 12 months and 24 months postoperatively. The study has the design of a parallel group to demonstrate the non-inferior clinical results of MIS-TLIF compared with the traditional O-TLIF.

ETHICS AND DISSEMINATION

The study will be performed according to Helsinki Declaration. The study protocol was approved by the Local Ethical Committee of Priorov National Medical Research Center of Traumatology and Orthopedics in August 2020. Preliminary and final results will be presented in peer-reviewed journals, especially orthopaedic and spine surgery journals, at national and international congresses.

TRIAL REGISTRATION NUMBER

NCT04594980.

Trends in lumbar spinal fusion-a literature review

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

Minimally invasive unilateral lumbar interbody fusion (UNILIF) in over-80-year-olds. Continuous series of 42 patients at 1.4 years' follow-up

INTRODUCTION

In lumbar stenosis, surgery aims to improve quality of life in increasingly elderly patients. Minimally invasive techniques better suit the requirements of elderly patients with increasing functional demand.

HYPOTHESIS

The UNILIF unilateral lumbar interbody fusion technique improves functional scores at 1 year in over-80 year-olds, with low morbidity.

METHOD

Patients undergoing minimally invasive decompression with transforaminal lumbar interbody fusion (TLIF) associated to unilateral pedicle screwing for degenerative lumbar stenosis were analyzed at a minimum 1 year's follow-up. SF12, Oswestry Disability Index (ODI) and Quebec scores and sagittal spinopelvic radiographic parameters were assessed at follow-up. Surgical and general complications were also collated.

RESULTS

In all, 42 patients (64.3% female; mean age, 83.7±2.9 years) were treated by UNILIF at levels L2-L3 (3.8%), L3-L4 (15.4%), L4-L5 (71.2%) and L5-S1 (9.6%). Mean follow-up was 520±226 days (range, 340-1166 days). Mean preoperative SF12 score was 77.5±10.9, with significant improvement at last follow-up: 81.9±138 (p<0.05). Mean preoperative ODI was 44.4%±14.0, with significant improvement at last follow-up: 32.4%±13.3 (p<0.001). Mean preoperative Quebec score was 42.9±19.9, with significant improvement at last follow-up: 28.5±21.9 (p<0.001). Spinopelvic sagittal balance was not affected by the UNILIF procedure. There were no cases of infection or severe general complications during follow-up, although 2 cases of non-union required revision surgery.

CONCLUSION

Lumbar stenosis surgery by UNILIF improved functional scores at 1 year, with low morbidity. It is a suitable strategy for degenerative lumbar stenosis in elderly patients.

LEVEL OF EVIDENCE

IV, non-comparative cohort study.