Interspinous Device Research Articles

Advancing the design of interspinous fixation devices for improved biomechanical performance: dual vs. single-locking set screw mechanisms and symmetrical vs. asymmetrical plate designs.

Interspinous devices were introduced in the field of spine surgery as an alternative to traditional pedicle screw fixation in selected patients for treatment of spinal stenosis and fixation. These devices designs have evolved from non-fixated extension blocks to sophisticated interspinous fixation devices (IFDs). There is an absence of literature comparing the biomechanical fixation strength of different IFD plate designs and the role of set screw locking systems. The aim of this study was to evaluate fixation strengths by bench testing static disassembly and pullout strength of two dissimilar IFD designs and locking mechanisms. We hypothesized that the InSpan (InSpan LLC, Burlington, MA, USA) dual-locking symmetrically IFD plate designed will have stronger fixation than the Aspen (ZimVie, Parsippany, NJ, USA) single-locking asymmetric IFD plate design. We conducted two biomechanical bench tests to evaluate the load to failure locking characteristics of symmetrical InSpan and asymmetrical Aspen IFD designs. Static pullout testing involved locking each IFD to the stainless steel and 40 pcf cellular polyurethane foam and measuring pullout load and displacement six times. Seven InSpan and two Aspen IFDs (including the "used" IFDs from the pullout testing) underwent static disassembly tests using a pair of disassembly fixtures positioned between the IFD plates to measure disassembly force and displacement. All tests were performed under ambient conditions using an INSTRON 8874 Bi-Axial Tabletop Servohydraulic Dynamic Testing System (INSTRON, Norwood, MA, USA), and data was collected at a 0.2 mm/s displacement control rate until the test was stopped when there was a drop in the continuously increasing force against resistance (gross failure). The InSpan IFD experienced 94.81% higher resistance to pullout compared to the Aspen IFD in static pullout testing (P<0.05), owing to its notably larger footprint area of 69.8%. Gross failure for both IFD implant designs occurred at the foam block-block interface. In static disassembly testing, pristine InSpan required 60.7% higher force over pristine Aspen and 401.3% for "used" IFDs. Gross failure was characterized by the gradual distraction of the plates and material removal at the set screw contact points. Implant failure at the block-implant interface emphasized the pivotal role of teeth design and the contact surface area of the plates in ensuring stability. The dual-locking symmetrical InSpan IFD outperformed single-locking asymmetric Aspen IFD in both static disassembly and pullout bench tests. This highlights the benefits of InSpan's improved design and its potential for enhanced long-term stability in spinal fixation applications.

Effectiveness of Interspinous Process Devices in Managing Adjacent Segment Degeneration Following Lumbar Spinal Fusion: A Systematic Review and Meta-Analysis.

Background: Adjacent segment degeneration (ASD) is a significant complication following lumbar spinal fusion, often necessitating further surgical interventions and impairing patient outcomes. Interspinous process devices were introduced as an alternative treatment for spinal stenosis and degenerative spondylolisthesis and can potentially reduce the incidence of ASDd. This systematic review and meta-analysis aims to evaluate the effectiveness of interspinous process devices or IPDs in managing ASD following a previous spinal fusion compared to traditional fusion techniques. Methods: Electronic databases, including PubMed, Embase, and the Cochrane Library, were queried for studies assessing IPDs against traditional lumbar fusion methods for managing ASD after previous lumbar fusion, which had been published between January 2014 and the present. Statistical analysis was conducted using Review Manager 5.4. Results: Seven retrospective cohort studies involving 546 patients met the inclusion criteria. The analysis revealed that IPDs were associated with a statistically significant reduction in the incidence of ASD (OR = 0.28, 95% CI: 0.16 to 0.51, p < 0.0001, and I2 = 0% after excluding outliers). The ODI demonstrated a non-significant trend towards improved outcomes with IPDs at the 2-year follow-up (SMD = -3.94; 95% CI: -11.72 to 3.85). Range of motion (ROM) was better preserved with IPDs compared to fusion (SMD = 0.00, 95% CI: -0.41 to 0.41, p = 1.00, I2 = 60%). The visual analogue scale or VAS lower back pain scores were significantly reduced at the 2-year follow-up (SMD = -0.69, 95% CI: -1.18 to -0.19, p = 0.006, and I2 = 74%). VAS leg pain showed consistent improvements (SMD = -0.29; 95% CI: -0.63 to 0.04). Intraoperative blood loss was significantly lower with IPDs (SMD = -2.07; 95% CI: -3.27 to -0.87, p = 0.0007, and I2 = 95%), and operation times were shorter (SMD = -2.22, 95% CI: -3.31 to -1.12, p < 0.0001, and I2 = 94%). Conclusions: The judicious use of IPDs might benefit a subset of patients, particularly those who are not suitable candidates for major corrective surgery.

Efficacy and safety of interspinous process device compared with alone decompression for lumbar spinal stenosis: A systematic review and meta-analysis.

Systematic review and meta-analysis. Interspinous process devices (IPD) were used as a treatment in selected patients with lumbar spinal stenosis (LSS). However, the use of IPD was still debated that it had significantly higher reoperation rates compared to traditional decompression. Therefore, the purpose of the meta-analysis was to evaluate the effectiveness and safety of IPD treatment in comparison to traditional treatment. The databases were searched of PubMed, Embase and the Cochrane, Chinese National Knowledge Infrastructure, Chongqing VIP Database and Wan Fang Database up to January 2024. Relevant studies were identified by using specific eligibility criteria and data was extracted and analyzed based on primary and secondary endpoints. A total of 13 studies were included (5 RCTs and 8 retrospective studies). There was no significant difference of Oswestey Disability Index (ODI) score in the last follow-up (MD = -3.81, 95% CI: -8.91-1.28, P = .14). There was significant difference of Visual Analog Scale (VAS) back pain scoring in the last follow-up (MD = -1.59, 95% CI: -3.09--0.09, P = .04), but there existed no significant difference of leg pain in the last follow-up (MD = -2.35, 95% CI: -6.15-1.45, P = .23). What's more, operation time, bleeding loss, total complications and reoperation rate had no significant difference. However, IPD had higher device problems (odds ratio [OR] = 9.00, 95% CI: 2.39-33.91, P = .001) and lesser dural tears (OR = 0.32, 95% CI: 0.15-0.67, P = .002) compared to traditional decompression. Although IPD had lower back pain score and lower dural tears compared with traditional decompression, current evidence indicated no superiority for patient-reported outcomes for IPD compared with alone decompression treatment. However, these findings needed to be verified in further by multicenter, double-blind and large sample RCTs.

Biomechanical investigation of a customized interspinous spacer system in the treatment of degenerative disc diseases: A finite element analysis

BackgroundA novel interspinous fixation system based on anatomical parameters and incorporating transfacetopedicular screws, was developed to treat degenerative disc diseases. The biomechanical characteristics of the novel system were evaluated using finite element analysis in comparison to other classical interspinous spacers. MethodsThe L1-S1 lumbar spine finite element models were surgically implanted with the novel system, Coflex and DIAM devices at the L4/L5 segment to assess the range of motion, the pression distribution of intervertebral disc, the peak stresses on the spinous process and implant during various motions. FindingsRange of motions of the L4/L5 surgical segment were reduced by 29.13%, 61.27%, 77.35%, 33.33%, and the peak stresses of intervertebral disc were decreased by 36.82%, 67.31%, 73.00%, 69.57% for the novel system in flexion, extension, lateral bending, and axial rotation when compared with the Coflex, and they were declined by 34.53%, 57.86%, 75.81%, 25.21%; 36.22%, 67.31%, 75.01%, 71.40% compared with DIAM. The maximum stresses of the spinous process were 29.93 MPa, 24.66 MPa, 14.45 MPa, 24.37 MPa in the novel system, and those of Coflex and DIAM were 165.3 MPa, 109 MPa, 84.79 MPa, 47.66 MPa and 52.59 MPa, 48.78 MPa, 50.27 MPa, 44.16 MPa during the same condition. InterpretationCompared to other interspinous spacer devices, the novel interspinous fixation system demonstrated excellent stability, effectively distributing load on the intervertebral disc, and reducing the risk of spinous process fractures. The personalized design of the novel interspinous fixation system could be a viable option for treating degenerative disc diseases.

Feasibility, safety, and efficacy of a new percutaneous interspinous device: a retrospective multicenter study.

To evaluate safety and efficacy of the novel percutaneous interspinous device (PID) for the treatment of symptomatic degenerative lumbar spinal stenosis (DLSS) in 3 different centers. From November 2016 to March 2020, 255 patients (male 125, mean age 71.2years old range 49-91years old) with neurogenic claudication, confirmed by electromyography, related to mono or bi-segmental lumbar central canal and/or foraminal stenosis were enrolled in the study. Magnetic resonance (MR) and/or computer tomography (CT), physical exam, and Visual Analogue Scale (VAS) and Zurich Claudication Questionnaire (ZCQ) were performed before and 6months after the procedure. All treatments were performed under fluoroscopic guidance with local anesthesia and mild sedation. Technical success was defined as correct placement of the Lobster® (Demetrios Medical, Firenze, Italy) PID as demonstrated by computer tomography (CT) performed immediately after treatment; spinoplasty was performed in selected patients. PID placement was accomplished with a 99.6% success rate (257/258). The one device that was not implanted was due to a spinous process fracture. In 28 patients, more than 1 device was implanted in the same session (max 3 PIDs); 6 patients required a second implant in different session. A total of 172 prophylactic spinoplasties were performed (59.3%). No major complications occurred; 3 device misplacements were successfully treated with percutaneous retrieval and new device deployment. 99.6% of patients experienced clinical improvement. Lobster PID is an effective and safe minimally invasive decompression method for central canal and neural foraminal stenosis when patients are correctly selected.

111 Interspinous Process Device Utilization and Reimbursement Vary by Provider Specialty and Care Setting

INTRODUCTION: Interspinous process devices (IPDs) are a popular less invasive treatment option for lumbar degenerative disease. Studies suggest they may yield initial symptomatic relief but are not better than traditional surgery in improving function or quality of life and may increase reoperation and costs. Ideal indications remain contested. METHODS: Centers for Medicare and Medicaid Services Physician/Supplier Procedure Summary data sets (2017-2020) were queried by CPT codes for lumbar interlaminar/interspinous process stabilization/distraction devices without fusion. Utilization rates were normalized per 10,000 lumbar fusions. RESULTS: IPD utilization increased by 329% from 2017-2020. Percutaneous IPD utilization increased to 31.8 (+1,267%), while open procedures decreased to 4.4 (-27%). Pain management/anesthesia placed the majority of IPDs and increased utilization the most (27.4, +1,387%). Physical medicine and rehabilitation (PM&amp;R) had the second-highest rate of utilization (3.5, +1,492%). Neurosurgery (2.3, -15%) and orthopedics (0.7, -63%) decreased utilization. Ambulatory surgical centers (ASCs) increased utilization the most (25.8, +907%). Outpatient procedures increased (9.2, +162%), while inpatient procedures decreased (1.2, -49%). IPD reimbursements decreased to $400 (-44.6%), with decreasing trends in percutaneous ($364, -28.6%) and open placement ($776, -6.8%). Reimbursements were highest for orthopedics ($800, +0.6%) and lowest for pain management/anesthesiology ($362, -26.7%). Reimbursements decreased across all settings, especially outpatient (-48.8%) and inpatient (-35.9%). CONCLUSIONS: Despite uncertainty of indications for IPDs, utilization increased by 329% when normalized to lumbar fusions to account for changes in disease prevalence. IPDs are increasingly placed by PM&amp;R and pain management in ASCs and outpatient settings. Utilization does not seem to be driven by reimbursement rates. It is unknown how the rapid increase in IPDs has affected clinical outcomes. Given the magnitude of increased utilization and limited data on the safety and efficacy of IPDs, closer examination of indications is warranted.

Bibliometric analysis of interspinous device in treatment of lumbar degenerative diseases.

In recent years, with the introduction of the concept of lumbar non-fusion, the interspinous device has emerged. The purpose of this study is to bibliometrically analyze the state, areas of interest, and emerging trends in the usage of interspinous devices for the treatment of lumbar degeneration disease, as well as related research fields. Between January 1, 2000 and June 14, 2023, a comprehensive collection of publications on the topic of interspinous devices in the treatment of lumbar degenerative disease (IDTLDD) was procured from the Web of Science. A bibliometric analysis and visualization were subsequently conducted, utilizing various tools including HisCite, VOSviewer, CiteSpace, and bibliometrix package. This process involved the gathering of data on the country, institution, author, journal, reference, and keywords. A comprehensive analysis of 401 publications sourced from 149 journals was conducted, with 1718 authors affiliated with 1188 institutes across 240 countries/regions. Notably, the United States emerged as the leading contributor with 134 published articles on interspinous devices in the treatment of lumbar degenerative disease (33.42%). The most productive institution was Capital Medical University, with (10, 2.49%) publications. The author with the highest publication output was Block, Jon E, with 10 publications. European Spine Journal demonstrated the highest level of productivity, with a publication of (n = 39, 9.73%). The term "X-Stop" was the most frequently utilized keyword, followed by "Lumbar spinal stenosis." The study identified various topics of current interest, such as "Invasive decompression" and "Coflex." The present study provides a comprehensive survey of research trends and developments in the application of interspinous device for the treatment of lumbar degenerative diseases, including relevant research findings and collaborative efforts among authors, institutions, and countries.

Is the interspinous process device safe and effective in elderly patients with lumbar degeneration? A systematic review and meta-analysis of randomized controlled trials.

Lumbar spinal stenosis is one of the most common diseases affecting the elderly that is characterized by the narrowing of the spinal canal and peripheral neural pathways which may cause back pain and neurogenic intermittent claudication in affected patients. Recently, as an alternative treatment between conservative therapy and decompression surgery, interspinous process device (IPD) such as X-stop, Coflex, DIAM, Aperius, Wallis, etc., has gained enough popularity. The purpose of this study was to evaluate the efficacy and safety of IPD in the treatment of degenerative lumbar spinal stenosis compared with decompression surgery. This study was a systematic review and meta-analysis of randomized controlled trials. 555 patients' samples were collected for this study. The Visual Analogue Scale and the Oswestry Disability Index were analyzed, as well as the Zurich Claudication Questionnaire For efficacy evaluation. Complication and reoperation rate was utilized for the assessment of safety. A comprehensive literature search was performed through Pubmed, EMBASE, Web of Science, and Cochrane Library until October 2023. Among the studies meeting the eligible criteria, any study in which IPD was utilized in the treatment of degenerative lumbar spinal stenosis was included in the current review. For efficacy evaluation, the Visual Analogue Scale and the Oswestry Disability Index were analyzed, as well as the Zurich Claudication Questionnaire. Complication and reoperation rates were utilized for the assessment of safety. Five randomized controlled trials with 555 patients were included. There were no significant differences in VAS leg pain (SMD - 0.08, 95% CI - 0.32 to 0.15) and back pain (SMD 0.09, 95%CI-0.27 to 0.45), ODI scores (MD 1.08, 95% CI - 11.23 to 13.39) and ZCQ physical function (MD-0.09, 95% CI-0.22 to 0.05) for IPD compared with decompression surgery. In terms of ZCQ symptom severity (MD - 0.22, 95% CI - 0.27 to - 016), decompression surgery showed superior to the IPD. As for complications (RR 1.08, 95% CI 0.36 to 3.27), the IPD had no advantages compared to decompression surgery, whereas inferior to it in reoperation rate (RR 2.58, 95% CI 1.67 to 3.96). This systematic review and meta-analysis indicated no superiority in the clinical outcome for IPD compared with decompression surgery. However, more clinical studies are warranted to determine the efficacy and safety of IPD.

Perspective: Efficacy and outcomes for different lumbar interspinous devices (ISD) vs. open surgery to treat lumbar spinal stenosis (LSS).

Interspinous devices (ISD) constitute a minimally invasive (MI) alternative to open surgery (i.e., laminectomy/decompression with/without fusion (i.e., posterior lumbar interbody fusion (PLIF)/posterolateral instrumented fusion (PLF)) for treating lumbar spinal stenosis (LSS). Biomechanically, static and/or dynamic ISD "offload" pressure on the disc space, increase intervertebral foraminal/disc space heights, reverse/preserve lordosis, limit range of motion (ROM)/stabilize the surgical level, and reduce adjacent segment disease (ASD). Other benefits reported in the literature included; reduced operative time (OR Time), length of hospital stay (LOS), estimated blood loss (EBL), and improved outcomes (i.e., ODI (Oswestry Disability Index), VAS (Visual Analog Scale), and/or SF-36 (Short-Form 36)). Various studies documented the relative efficacy and outcomes of original (i.e., Wallis), current (i.e., X-STOP, Wallis, DIAM, Aperius PercLID), and new generation (i.e., Coflex, Superion Helifix, In-Space) ISD used to treat LSS vs. open surgery. Although ISD overall resulted in comparable or improved outcomes vs. open surgery, the newer generation ISD provided the greatest reductions in critical cost-saving parameters (i.e., OR time, LOS, and lower reoperation rates of 3.7% for Coflex vs. 11.1% for original/current ISD) vs. original/current ISD and open surgery. Further, the 5-year postoperative study showed the average cost of new generation Coflex ISD/decompressions was $15,182, or $11,681 lower than the average $26,863 amount for PLF. Patients undergoing new generation ISD for LSS exhibited comparable or better outcomes, but greater reductions in OR times, EBL, LOS, ROM, and ASD vs. those receiving original/current ISD or undergoing open surgery.

Preliminary Results of Lumbar Stabilization with Interspinous Process Devices for Lumbar Canal Stenosis

Preliminary Results of Lumbar Stabilization with Interspinous Process Devices for Lumbar Canal Stenosis

Characterizing utilization patterns and reoperation risk factors of interspinous process devices: analysis of a national claims database.

Interspinous process devices (IPDs) were developed as minimally invasive alternatives to open decompression surgery for spinal stenosis. However, given high treatment failure and reoperation rates, there has been minimal adoption by spine surgeons. This study leveraged a national claims database to characterize national IPD usage patterns and postoperative outcomes after IPD implantation. Using the PearlDiver database, we identified all patients who underwent 1- or 2-level IPD implantation between 2010 and 2018. Univariate and multivariable logistic regression was performed to identify predictors of the number of IPD levels implanted and reoperation up to 3 years after the index surgery. Right-censored Kaplan-Meier curves were plotted for duration of reoperation-free survival and compared with log-rank tests. Patients (n = 4865) received 1-level (n = 3246) or 2-level (n = 1619) IPDs. Patients who were older (adjusted odds ratio [aOR] 1.02, 95% confidence interval [CI] 1.01-1.03, P < .001), male (aOR 1.31, 95% CI 116-1.50, P < .001), and obese (aOR 1.19, 95% CI 1.05-1.36, P < .01) were significantly more likely to receive a 2-level IPD than to receive a 1-level IPD. The 3-year reoperation rate was 9.3% of patients when mortality was accounted for during the follow-up period. Older age decreased (aOR 0.97, 95% CI 0.97-0.99, P = .0039) likelihood of reoperation, whereas 1-level IPD (aOR 1.37, 95% CI 1.01-1.89, P = .048), Charlson Comorbidity Index (aOR 1.07, 95% CI 1.01-1.14, P = .018), and performing concomitant open decompression increased the likelihood of reoperation (aOR 1.68, 95% CI 1.35-2.09, P = .0014). Compared with 1-level IPDs, 2-level IPDs were implanted more frequently in older, male, and obese patients. The 3-year reoperation rate was 9.3%. Concomitant open decompression with IPD placement was identified as a significant risk factor for subsequent reoperation and warrants future investigation.

Biomechanical characteristics of a novel interspinous distraction fusion device in the treatment of lumbar degenerative diseases: a finite element analysis

BackgroundA novel interspinous distraction fusion (ISDF) device has been used to treat lumbar degenerative diseases. As a minimally invasive technique, ISDF differs from the traditional interspinous process distraction devices. Currently, biomechanical studies on ISDF are rare.ObjectiveTo investigate the biomechanical properties of the ISDF device (BacFuse) which is used to treat lumbar degenerative diseases.MethodsThree-dimensional L3-L5 models were created. The models were divided into four groups: intact (M1), local decompression alone (M2), internal fixation alone (M3) and local decompression combined with internal fixation (M4), based on different surgical procedures. Local laminectomy was performed to resect the lower part of the L4 lamina and the upper part of the L5 lamina at the right lamina of L4/5 in the M2 and M4 groups. After meshing the models elements, Abaqus were used to perform the finite element (FE) analysis. The intervertebral range of motion (ROM) was measured during flexion, extension, left lateral bending, right lateral bending, left rotation and right rotation under a follower load of 400 N with a 7.5Nm moment. The distributions of disc and facet joint stresses were observed and recorded. Spinal vertebral stress was compared, and internal fixation device stress was observed.ResultsThe ROM of L4/5 in M2 increased in flexion, extension, left lateral bending, right lateral bending, left rotation and right rotation compared with that in M1. In all motion directions, the ROM at L4/5 decreased, and the ROM at L3/4 increased after implantation of the ISDF device in M3 and M4 groups. The disc stress and facet joint stresses in the instrumented segment decreased after implantation of the ISDF device. The spinous process loaded a certain amount of stress in M3 and M4 groups. The spikes of the internal fixation device were loaded with the maximum stress.ConclusionBacFuse exhibited a reduction in intervertebral ROM, as well as decreased stress on the intervertebral disc and facet joint, while also demonstrating a discernible impact on the upper adjacent segment.

Prospective 5-year follow-up of L5-S1 versus L4-5 midline decompression and interspinous-interlaminar fixation as a stand-alone treatment for spinal stenosis compared with laminectomies.

Spinal stenosis treatment includes laminectomies with or without fusion or with interspinous distraction with or without fixation. Lack of published data on interspinous fixation devices (IFD) at L5-S1 is less considered as an option due to the smaller anatomical S1 spinous process and the higher stresses from the immobile sacrum. Our objective was to evaluate the outcomes of an IFD used as a stand-alone treatment for spinal stenosis at L5-S1 and L4-5 compared to historical data on open laminectomies. Prospective comparative cohort study (Level 2) looking at collected preoperatively and postoperatively Visual Analog Scores (VAS) and Oswestry Disability Index (ODI) data, complications, and revision rates on 100 consecutive patients with spinal stenosis treated with midline decompression and InSpan (InSpan LLC, Malden, MA, USA) IFD, at L5-S1 and L4-5, up to five-year follow-up. All patients were treated by a single surgeon in an academic private practice. Historical published outcome data for open laminectomies were compared. Among the 100 patients, 45 underwent surgery at L5-S1 with a mean VAS pain score that decreased by 75% and ODI improved by 63% (P<0.001). Fifty-five patients had surgery at L4-5 with mean VAS and ODI scores improved by 80% and 66% (P<0.001) respectively. Preoperative and postoperative ODI and preoperative VAS scores were similar at L5-S1 and L4-5, however, postoperative VAS scores were significantly less for L4-5 versus L5-S1 (P<0.01). All surgeries were completed in less than one hour. There was a total of one L4-5 revision (1.8%) and two L5-S1 revisions (4.4%). Comparable laminectomy data showed decrease in VAS and ODI scores by 51% and 62% (P<0.05). The reoperation rate for laminectomies at five to ten years varied up to 24%. Spinal stenosis patients treated with midline decompression and InSpan IFD, used as a stand-alone treatment for interspinous-interlaminar fixation, at L4-5 and L5-S1, showed improved outcome scores and low complication and revision rates at five years and were comparable to historical open laminectomy data. InSpan is a successful substitute for laminectomies in selected patients and was performed in less than 60 minutes. We recommend choosing the appropriately sized implant to achieve adequate distraction decompression to avoid recurrent symptoms.

Incidence of subsequent surgical decompression following minimally invasive approaches to treat lumbar spinal stenosis: A retrospective review.

Surgical decompression is the definitive treatment for managing symptomatic lumbar spinal stenosis; however, select patients are poor surgical candidates. Consequently, minimally invasive procedures have gained popularity, but there exists the potential for failure of therapy necessitating eventual surgical decompression. To evaluate the incidence and characteristics of patients who require surgical decompression following minimally invasive procedures to treat lumbar spinal stenosis. Retrospective review. Patients who underwent minimally invasive procedures for lumbar spinal stenosis (Percutaneous Image-guided Lumbar Decompression [PILD] or interspinous spacer device [ISD]) and progressed to subsequent surgical decompression within 5 years. The primary outcome was the rate of surgical decompression within 5 years following the minimally invasive approach. Secondary outcomes included demographic and comorbid factors associated with increased odds of requiring subsequent surgery. Patient data were collected using the PearlDiver-Mariner database. The rate of subsequent decompression was described as a percentage while univariable and multivariable regression analysis was used for the analysis of predictors. A total of 5278 patients were included, of which 3222 (61.04%) underwent PILD, 1959 (37.12%) underwent ISD placement, and 97 (1.84%) had claims for both procedures. Overall, the incidence of subsequent surgical decompression within 5 years was 6.56% (346 of 5278 patients). Variables associated with a significantly greater odds ratio (OR) [95% confidence interval (CI)] of requiring subsequent surgical decompression included male gender and a prior history of surgical decompression by 1.42 ([1.14, 1.77], p = 0.002) and 2.10 times ([1.39, 3.17], p < 0.001), respectively. In contrast, age 65 years and above, a diagnosis of obesity, and a Charlson Comorbidity Index score of three or greater were associated with a significantly reduced OR [95% CI] by 0.64 ([0.50, 0.81], p < 0.001), 0.62 ([0.48, 0.81], p < 0.001), and 0.71 times ([0.56, 0.91], p = 0.007), respectively. Minimally invasive procedures may provide an additional option to treat symptomatic lumbar spinal stenosis in patients who are poor surgical candidates or who do not desire open decompression; however, there still exists a subset of patients who will require subsequent surgical decompression. Factors such as gender and prior surgical decompression increase the likelihood of subsequent surgery, while older age, obesity, and a higher Charlson Comorbidity Index score reduce it. These findings aid in selecting suitable surgical candidates for better outcomes in the elderly population with lumbar spinal stenosis.

Percutaneous removal and replacement of a novel percutaneous interspinous device.

Objective: The aim of this study is to explain the technique used for removing and replacing a novel percutaneous interspinous device (PID).Procedure: Three male patients, with a mean age of 66years (range 62-72), were included in the study due to displacement (N = 2) or misplacement (N = 1) of the novel PID. This occurred after a mean of 23.3 ± 10.5 days from the initial placement (range 13-34) at the L4-L5 level (N = 1) and L3-L4 level (N = 2). Following the removal of the PID, four new devices were implanted.Conclusion: The novel PID can be safely removed either immediately after its placement during the procedure or after a certain period of days or months from its implantation. The removal procedure can be performed percutaneously under imaging guidance, by closing the four retractable wings, using the same instrumentation as utilized during the initial implantation.

Pain Management Interventions in Lumbar Spinal Stenosis: A Literature Review.

Lumbar spinal stenosis (LSS) occurs due to the narrowing of the space within the vertebral canal and or intervertebral foramina. This results in the compression of the spinal cord and possibly the roots of the spinal nerves.Lower back pain and neurogenic claudication (NC) are major symptoms of spinal stenosis. This is a literature review that summarizes the important findings pertaining to pain management of spinal stenosis. Twenty-four original articles were assessed. Pain can be treated through non-invasive or surgical methods. Conservative techniques include physical exercises, epidural corticosteroid injection, local anesthetic injection therapy, and oral analgesics. Surgical intervention deals with the decompression of the affected spinal region, with or without vertebral fusion surgery. Other novel surgical techniques include implantation of specific equipment, known as interspinous spacer devices and minimally invasive lumbar decompression (MILD). Most studies offering a comparative analysis have demonstrated that surgical intervention is more efficacious than non-surgical interventions to manage pain associated with spinal stenosis.

Complications and radiographic changes after implantation of interspinous process devices: average eight-year follow-up

PurposeThis study aims to evaluate complications, clinical outcomes, and radiographic results following Coflex implantation.MethodsWe retrospectively studied 66 patients who had decompressive surgery combined with Coflex implantation to treat lumbar spinal stenosis. All imaging data were collected and examined for imaging changes. Clinical outcomes, included Oswestry Disability Index (ODI), back and leg visual analog scale (VAS) scores, were evaluated before surgery, six months after surgery and at the last follow-up. The number of complications occurring after five years of follow-up was counted. All reoperation cases were meticulously recorded.Results66 patients were followed up for 5–14 years. The VAS and ODI scores were significantly improved compared with baseline. Heterotopic Ossification (HO) was detectable in 59 (89.4%). 26 (39.4%) patients had osteolysis at the contact site of Coflex with the spinous process. Coflex loosening was detected in 39 (60%) patients. Spinous process anastomosis was found in 34 (51.5%) patients. There was a statistically significant difference in the VAS score of back pain between patients with and without spinous process anastomosis. Nine cases of lumbar spinal restenosis were observed, and prosthesis fracture was observed in one case.ConclusionOur study identified various imaging changes after Coflex implantation, and majority of them did not affect clinical outcomes. The majority of patients had HO, but osteolysis and Coflex loosening were relatively rare. The VAS score for back pain of these patients was higher if they have spinous process anastomosis. After five-year follow-up, we found lumbar spinal restenosis and prosthesis fracture cases.

Synovial Cyst in the Setting of an Interspinous Fusion Device

Synovial cysts of the spine are degenerative cystic lesions that can lead to severe symptoms secondary to compression of the spinal cord, individual nerve roots, and/or the cauda equina. Some believe the etiology of this entity is related to increased motion across the facet joint and instability. We report a case of a lumbar synovial cyst located at the same level as a previously inserted spinous process fusion device. This case illustrates that, unlike a transpedicular instrumented fusion where the risk of synovial cyst formation is zero, a spinal process fusion can still lead to synovial cyst formation likely due to persistent micromotion across that segment.

Instrumented Posterior Arthrodesis of the Lumbar Spine: Prospective Study Evaluating Fusion Outcomes in Patients Receiving an Interspinous Fixation Device for the Treatment of Degenerative Spine Diseases.

Prospective evaluation of radiographic fusion outcomes in patients receiving instrumented posterior arthrodesis of the lumbar spine using a minimally invasive interspinous fixation device. All patients (n = 110) from a single US physician's practice who received instrumented posterior arthrodesis of the lumbar spine with a minimally invasive interspinous fixation device in the calendar year 2020 were invited to return for a follow-up CT scan to radiographically assess fusion. Forty-three patients, representing 69 total treated levels, consented to participate and received a lumbar CT scan at a mean of 459 days post-surgery (177 to 652). The interspinous/interlaminar fusion was assessed by 3 independent radiologists using a novel grading scale. Spinous process fractures were also assessed. 92.8% of the assessed levels were considered fused. There were no intraoperative spinous process fractures. There were 4 spinous process fractures (5.8%) identified on CT imaging, all of which were asymptomatic and healed without subsequent intervention. There were no instances of device mechanical failure or device-related reoperation. Instrumented posterior arthrodesis of the lumbar spine using a minimally invasive interspinous fixation device provides clinically meaningful fusion rates with no reoperations and a low risk of spinous process fracture or other device-related complications.

Interspinous-Interbody Fusion via a Strictly Lateral Surgical Approach: A Biomechanical Stabilization Comparison to Constructs Requiring Both Lateral and Posterior Approaches.

Objective Lumbar fusion performed through lateral approaches is becoming more common. The interbody devices are generally supported by supplemental posterior fixation implanted through a posterior approach, potentially requiring a second incision and intraoperative repositioning of the patient. A minimally invasive lateral interspinous fixation device may eliminate the need for intraoperative repositioning and avoid disruption of the supraspinous ligament. The objective of this in vitrobiomechanical study was to investigate segmental multidirectional stability and maintenance of foraminal distraction of a lateral interspinous fixation device compared to commonly used pedicle screw and facet screw posterior fixation constructs when combined with lumbar interbody cages. Methods Six human cadaver lumbar spine specimens were subjected to nondestructive quasistatic loading in the following states: (1) intact; (2) interspinous fixation device alone and (3) with lateral interbody cage; (4) lateral lumbar interbody cage with bilateral pedicle screws; (5) lateral lumbar interbody cage with unilateral pedicle screws; and (6) lateral lumbar interbody cage with facet screws. Multidirectional pure bending in 1.5 Nm increments to 7.5 Nm, and 7.5 Nm flexion-extension bending with a 700 N compressive follower load were performed separately with optoelectronic segmental motion measurement. Relative angular motions of L2-L3, L3-L4, and L4-L5 functional spinal units were evaluated, and the mean instantaneous axis of rotation in the sagittal plane was calculated for the index level.Foraminal height was assessed during combined flexion-extension and compression loading for each test construct. Results All implant configurations significantly restricted flexion-extension motion compared with intact (p < 0.05). No significant differences were found in flexion-extension when comparing the different posterior implants combined with lateral lumbar interbody cages. All posterior fixation devices provided comparable neuroforaminal distraction and maintained distraction during flexion and extension. Conclusions When combinedwith lateral lumbar interbody cages, the minimally invasive lateral interspinous fixation device effectively stabilized the spine and maintained neuroforaminal distraction comparable to pedicle screw constructs or facet screws. These results suggest the lateral interspinous fixation device may provide a favorable alternative to other posterior systems that require patient repositioning during surgery and involve a greater disruption of native tissues.