Coflex interspinous process dynamic stabilization for lumbar spinal stenosis: Long-term follow-up

Comparison of clinical efficacy and radiological findings of interspinous dynamic stabilization system versus unilateral biportal endoscopy for lumbar spinal stenosis: a retrospective cohort study

BACKGROUND

Posterior lumbar interbody and fusion (PLIF) for lumbar spinal stenosis (LSS) has declined in recent years, with non-fusion techniques such as the interspinous dynamic stabilization system (IDSS) and unilateral biportal endoscopy (UBE) gaining prominence. However, there remains a paucity of comparative studies directly evaluating the therapeutic efficacy between these two distinct non-fusion approaches-IDSS as a motion-preserving stabilization method and UBE as a minimally invasive decompression technique‌. This investigation seeks to systematically assess and contrast both clinical efficacy and radiological findings associated with IDSS and UBE interventions in LSS management.

METHODS

This retrospective cohort study analyzed 209 patients with LSS treated between January 2015 and January 2022, stratified into two cohorts: the IDSS group (n = 112) and the UBE group (n = 97). Demographic and perioperative parameters, including age, gender, body mass index (BMI), hospital stay, operative time, intraoperative fluoroscopy frequency, blood loss, incision length and postoperative complications, were systematically documented for comparative analysis‌. Clinical outcomes were evaluated using the Visual Analogue Scale (VAS) for low back and leg pain and the Oswestry Disability Index (ODI) at four intervals: Preoperative, 1-month postoperative, 3-month postoperative, and the final follow-up. Therapeutic efficacy was further quantified at the final follow-up utilizing the modified MacNab criteria. Radiographic findings compared preoperative and final follow-up measurements across four parameters: segmental range of motion (SROM), intervertebral space height (ISH), facet joint preservation rate (FJPR) and dural sac cross-sectional surface area expansion rate (DSCAER).

RESULTS

Baseline characteristics including age, sex, BMI, surgical levels, and intraoperative fluoroscopy frequency showed no statistically significant differences between groups (P > 0.05). Regarding clinical outcomes, the UBE group demonstrated superior performance than the IDSS group, including operative duration (61.10 ± 10.39 vs. 70.59 ± 11.21 min), estimated blood loss (32.06 ± 10.11 vs. 52.94 ± 12.85 ml), incision length (1.85 ± 0.26 vs. 5.68 ± 0.69 cm), hospital stay (4.17 ± 0.93 vs. 5.82 ± 1.16 days), and complication rates (18.75% vs. 9.28%) (all P < 0.05). Both groups exhibited significant postoperative improvements in low back pain VAS, leg pain VAS, and ODI scores at 1-month, 3-month, and final follow-up intervals compared to preoperative baselines (P < 0.05). Intergroup comparisons of these functional outcomes revealed no significant differences across all timepoints (P > 0.05). Modified MacNab criteria showed comparable excellent/good rates between cohorts (IDSS: 84.82% vs. UBE: 89.69%, P > 0.05). ‌Radiographic findings:‌ At final follow-up, the UBE group maintained preoperative SROM in the operated segments (P > 0.05), whereas the IDSS group showed significant SROM restriction (ΔSROM=-2.09 ± 0.91º, P < 0.05). No significant differences were observed in ISH, FJPR, and DSCAER between the two groups postoperatively compared to preoperative values, or in intergroup comparisons (P > 0.05).

CONCLUSION

Both IDSS and UBE can effectively alleviate pain and improve quality of life in patients with LSS, achieving satisfactory clinical outcomes. Compared to IDSS, UBE is associated with minimized tissue trauma, fewer surgical complications and better preservation of SROM. These advantages position UBE as the preferentially recommended surgical approach for LSS.

Coflex Interspinous Stabilization with Decompression for Lumbar Spinal Stenosis: An Average 14-Year Follow-Up

Background: This study aimed to evaluate the long-term clinical usefulness and radiologic changes around the Coflex device following decompression with Coflex insertion for degenerative lumbar spinal stenosis (DLSS), with an average follow-up of 14 years. Methods: This retrospective study included 147 patients who underwent decompression and Coflex insertion for single-level DLSS at a single institution between January 2007 and December 2010. Patients with spinal stenosis unresponsive to 3 months of conservative treatment were treated surgically. The mean follow-up duration was 173.9 ± 23.7 (range, 119-214) months. Results: The mean visual analog scale score decreased from 8.22 ± 1.06 preoperatively to 2.08 ± 1.58 postoperatively. Intervertebral disc height and foramen height at the Coflex insertion site decreased by 5.3% and 2.0%, respectively, after surgery. The reoperation rate at the operated site was 25% (n = 37). A significantly higher reoperation rate was observed in patients with translational instability (odds ratio [OR], 7.77; 95% confidence interval [CI], 2.453-24.658; p < 0.01) and angular instability (OR, 1.59; 95% CI, 0.492-5.133; p < 0.001). Eight patients underwent reoperation due to rapid progression of instability within 2 years of Coflex insertion; thereafter, a similar cumulative incidence rate was consistently observed. The adjacent-segment reoperation rate was 10.8% (n = 16). Conclusions: The Coflex interspinous device helps preserve disc and foramen height but is associated with a high reoperation rate, particularly in patients with spinal instability. Therefore, careful patient selection is crucial when considering its use.

Evaluating 5-year outcomes of interlaminar devices as an adjunct to decompression for symptomatic lumbar spinal stenosis

PURPOSE

To assess and compare 5-year outcomes following uninstrumented spinal decompression and decompression with interlaminar device (ILD). To determine whether improvement in clinical outcomes correlated with changes in the radiological indices studied. This is because comparative literature between the above two procedures is limited past the 2-year timeframe.

METHODS

We conducted a retrospective review of prospectively collected data from a single surgeon across 116-patients who underwent spinal decompression with or without ILD insertion between 2007 and 2015. Patients with symptomatic LSS who met the study criteria were offered spinal decompression with ILD insertion. Patients who accepted ILD were placed in the D + ILD group (n = 61); while those opting for decompression alone were placed in the DA group (n = 55). Clinical outcomes were assessed preoperatively and up to 5-years postoperatively using the ODI, Eq. 5d, VAS back and leg pain, and SF-36. Radiological indices were assessed preoperatively and up to 5-years postoperatively.

RESULTS

Both groups showed statistically significant (p < 0.001) improvement in all clinical outcome indicators at all timepoints as compared to their preoperative status. The D + ILD group achieved significant improvement in radiological parameters namely foraminal height and posterior disc height in the immediate postoperative period that was maintained while the DA group did not.

CONCLUSION

Our study found that in the management of LSS, clinical outcomes between those patients undergoing decompression alone compared to decompression with ILD showed statistically significant improvement in VAS back pain and radiological parameters namely foraminal height and posterior disc height at the 5-year mark. ILD does not predispose to increased reoperation rates.

The effect of interlaminar Coflex stabilization in the topping-off procedure on local and global spinal sagittal alignment

PURPOSE

To investigate the effect of interlaminar Coflex stabilization (ICS) at various segments in the topping-off procedure on local and global spinal sagittal alignment.

METHODS

Eighty-nine consecutive patients with degenerative lumbar spinal stenosis (DLSS) who underwent ICS and transforaminal lumbar interbody fusion (TLIF) were retrospectively reviewed. They were divided into Group A (L4-L5 ICS + L5-S1 TLIF), Group B (L3-L4 ICS + L4-S1 TLIF), and Group C (L2-L3 ICS + L3-S1 TLIF) according to their fusion levels. The measured local sagittal parameters included the implanted segmental angle (ISA), intervertebral disc angle (IDA), intervertebral foreman height (IFH), and disc height. The assessed global sagittal parameters included thoracic kyphosis, lumbar lordosis (LL), the fused segment angle (FSA), the sacral slope, the pelvic tilt, pelvic incidence, and the sagittal vertical axis. The Oswestry Disability Index (ODI) and visual analog scales (VAS) were recorded to evaluate the clinical outcomes.

RESULTS

Regarding the local alignment parameters, the ISA and IDA decreased immediately after surgery in Groups A and B, followed by an increase at the last follow-up (all, P < 0.05). Conversely, the IFH of Groups A and B first increased after surgery and then decreased to approximately the original value (all, P < 0.05). No significant differences were evident between the local sagittal parameters at different time points in Group C. Regarding the global sagittal profiles, the LL and FSA exhibited a significant postoperative increase (both at P < 0.05) in all the groups. All three groups displayed significant improvements in the ODI, VAS-back pain, and VAS-leg pain. Furthermore, 4.5% (4/89) of the patients exhibited radiographic adjacent segment degeneration (ASD) at the last follow-up.

CONCLUSION

ICS during topping-off surgery led to a temporary loss of local lordosis, especially in the lower lumbar segment, while the intervertebral space realigned after middle-term follow-up. The topping-off procedure with ICS is a feasible and promising surgical option of DLSS since it reduces fusion levels and prevents ASD development.

Efficacy and Safety of Lumbar Dynamic Stabilization Device Coflex for Lumbar Spinal Stenosis: A Systematic Review and Meta-analysis

BACKGROUND

This systematic review and meta-analysis were performed to investigate evidence for the comparison of lumbar dynamic stabilization device Coflex (Surgalign, Deerfield, IL) with posterior lumbar fusion for lumbar spinal stenosis).

METHODS

Relational databases were searched to October 2022. The main outcome measures included operation time, Japanese Orthopedic Association score (JOA), visual analog scale (VAS), Oswestry disability index (ODI), total complications, and adjacent segment degeneration (ASD). Statistical analysis was performed with Review Manager 5.3 (Cochrane Collaboration).

RESULTS

A total of 26 studies were included. The main results of this meta-analysis showed lumbar dynamic stabilization device Coflex had shorter operation time (mean difference [MD] -50.77 min, 95% CI -57.24 to -44.30, P < 0.00001), less intraoperative blood loss (MD -122.21 mL, 95% CI -129.68 to -94.74, P < 0.00001), and shorter hospital stays (MD -3.21 days, 95% CI -4.04 to -2.37, P < 0.00001). What's more, the JOA score and ODI score were higher in the Coflex group during early follow-up. Yet, there was no significant difference between the 2 groups with the extension of follow-up time. Moreover, the Coflex group had a lower VAS score than fusion treatment (P < 0.00001). Finally, the Coflex group had lower total complications rate (P = 0.03), lower ASD rate (P = 0.001), and higher range of motion (P < 0.00001), but there was no significant difference in reoperation rate and internal fixation problems rate.

CONCLUSIONS

Current evidence suggests that lumbar dynamic stabilization device Coflex is superior to posterior lumbar fusion in early follow-up. However, considering that the dynamic stabilization device group also has its limitations, these findings need to be further verified by multicenter, double-blind, and large-sample randomized controlled trials.

Biomechanical Evaluation of Transforaminal Lumbar Interbody Fusion with Coflex-F and Pedicle Screw Fixation: Finite Element Analysis of Static and Vibration Conditions

OBJECTIVE

To investigate the biomechanics of transforaminal lumbar interbody fusion (TLIF) with interspinous process device (IPD) or pedicle screw fixation under both static and vibration conditions by the finite element (FE) method.

METHOD

A validated FE model of the L1-5 lumbar spine was used in this study. This FE model derived from computed tomography images of a healthy female adult volunteer of appropriate age. Then the model was modified to simulate L3-4 TLIF. Four conditions were compared: (i) intact; (ii) TLIF combined with bilateral pedicle screw fixation (BPSF); (iii) TLIF combined with U-shaped IPD Coflex-F (CF); and (iv) TLIF combined with unilateral pedicle screw fixation (UPSF). The intact and surgical FE models were analyzed under static and vibration loading conditions respectively. For static loading conditions, four motion modes (flexion, extension, lateral bending, and axial rotation) were simulated. For vibration loading conditions, the dynamic responses of lumbar spine under sinusoidal vertical load were simulated.

RESULT

Under static loading conditions, compared with intact case, BPSF decreased range of motion (ROM) by 92%, 95%, 89% and 92% in flexion, extension, lateral bending and axial rotation, respectively. While CF decreased ROM by 87%, 90%, 69% and 80%, and UPSF decreased ROM by 84%, 89%, 66% and 82%, respectively. Compared with CF, UPSF increased the endplate stress by 5%-8% in flexion, 7%-10% in extension, 2%-4% in lateral bending, and decreased the endplate stress by 16%-19% in axial rotation. Compared with CF, UPSF increased the cage stress by 9% in flexion, 10% in extension, and decreased the cage stress by 3% in lateral bending, and 13% in axial rotation. BPSF decreased the stress responses of endplates and cage compared with CF and UPSF. Compared BPSF, CF decreased the facet joint force (FJF) by 6%-13%, and UPSF decreased the FJF by 4%-12%. During vibration loading conditions, compared with BPSF, CF reduced maximum values of the FJF by 16%-32%, and vibration amplitudes by 22%-35%, while UPSF reduced maximum values by 20%-40%, and vibration amplitudes by 31%-45%.

CONCLUSION

Compared with other surgical models, BPSF increased the stability of lumbar spine, and also showed advantages in cage stress and endplate stress. CF showed advantages in IDP and FJF especially during vertical vibration, which may lead to lower risk of adjacent segment degeneration. CF may be an effective alternative to pedicle screw fixation in TLIF procedures.

Decompression and Interlaminar Stabilization for Lumbar Spinal Stenosis: A Cohort Study and Two-Dimensional Operative Video

Background and Objectives: Lumbar spinal stenosis is one of the most common causes of disability in the elderly and often necessitates surgical intervention in patients over the age of 65. Our study aimed to evaluate the clinical efficacy of interlaminar stabilization following decompressive laminectomy in patients with lumbar stenosis without instability. Materials and Methods: Twenty patients with lumbar stenosis underwent decompressive laminectomy and interlaminar stabilization at our academic institution. Clinical outcomes were measured using the visual analog scale (VAS) and Oswestry disability index (ODI) at the 2-month, 6-month, and 1-year postoperative visits, and these outcomes were compared to the preoperative scores. Results: The average VAS scores for low back pain significantly improved from 8.8 preoperatively to 4.0, 3.7, and 3.9 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average VAS scores for lower extremity pain significantly improved from 9.0 preoperatively to 2.7, 2.5, and 2.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average ODI scores significantly improved from 66.6 preoperatively to 23.8, 23.3, and 24.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). There was no statistical significance for difference in VAS or ODI scores between 2 months, 6 months, and 1 year. One patient had an intraoperative durotomy that was successfully treated with local repair and lumbar drainage. Another patient had progression of stenosis and had to undergo bilateral facetectomy and fusion. Conclusions: Decompressive laminectomy and interlaminar stabilization in patients with spinal claudication and low back pain is a good surgical option in the absence of instability and may provide significant clinical improvement of pain and functional disability.