A minimum 8-year follow-up comparative study of decompression and coflex stabilization with decompression and fusion

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.

Five-year radiological outcomes between decompression alone and decompression with an interlaminar device for lumbar spinal stenosis

Background

There is limited literature regarding radiological outcomes in the use of interlaminar devices as an adjunct to decompression compared to decompression alone (DA) for symptomatic lumbar spinal stenosis (LSS). This study aims to assess and compare 5-year radiological outcomes following spinal decompression and decompression with ILD (D + ILD).

Methods

We conducted a retrospective review of prospectively collected data of 94 patients who underwent spinal decompression with or without ILD insertion between 2007-2015. Patients with symptomatic LSS who met the study criteria were offered spinal decompression with or without ILD insertion. Those patients who accepted ILD insertion were placed in the D + ILD group (n=39); while those opting for DA, were placed in the DA group (n=55). Radiological indices were assessed preoperatively, immediate post-operative, 2 years and 5 years postoperatively.

Results

There were a total of 94 patients with 55 in the DA group and 39 in the D + ILD group. In both groups, there was no significant change post-operatively in the sagittal balance parameters namely, the mean pelvic incidence, pelvic tilt, sacral slope and pelvic incidence minus lumbar lordosis (PI - LL) during the 5-year follow-up. Comparing between the groups, there was no significant difference in sagittal balance parameters. Comparing between DA versus D + ILD, there was no significant difference in overall lordosis, but the D + ILD had a significant reduction in sagittal angle (at the index level) of 2.3° compared to the DA group (P=0.01). In the control group, there was no significant difference in the anterior disc, posterior disc and foraminal height post-operatively. In the D + ILD group, there was a significant mean increase of 1.3 mm in anterior disc height, 1.8 mm in posterior disc height and 4.7 mm in foraminal height compared to the control group. In both groups, there was significant improvement in all clinical outcomes namely 36-item short form survey physical component summary (SF36 PCS), 36-item short form survey mental component summary (SF36 MCS) and visual analogue scale (VAS). Comparing the groups, there was significant improvement in the D + ILD group in SF36 MCS (P=0.01) but no difference in SF36 PCS or VAS. Reoperation rates were equivalent.

Conclusions

Our study found that in the management of lumbar stenosis, the use of an ILD as an adjunct device compared to DA had significant improvement in anterior disc, posterior disc and foraminal height with expected focal kyphosis at the level of intervention without change in the lumbar lordosis and sagittal balance at 5 years.

Effects of dynamic and rigid implantation on biomechanical characteristics of different sagittal alignment lumbar after single- or double-level spinal fixations: a finite-element modeling study

BACKGROUND

Although it is critical to understand the accelerated degeneration of adjacent segments after fusion, the biomechanical properties of the spine have not been thoroughly studied after various fusion techniques. This study investigates whether four Roussouly's sagittal alignment morphotypes have different biomechanical characteristics after different single- or double-level spinal fixations.

METHODS

The parametric finite element (FE) models of Roussouly's type (1-4) were developed based on the radiological data of 625 Chinese community population. The four Roussouly's type models were reassembled into four fusion models: single-level L4-5 Coflex fixation model, single-level L4-5 Fusion (pedicle screw fixation) model, double-level Coflex (L4-5) + Fusion (L5-S1) model, and double-level Fusion (L4-5) + Fusion (L4-5) model. A pure moment of 7.5 Nm was applied to simulate the physiological activities of flexion, extension, lateral bending and axial rotation.

RESULTS

Both single-level and double-level spinal fixation had the greatest effect on lumbar range of motion, disc pressure, and annulus fibrosis stress in flexion, followed by lateral bending, extension, and axial rotation. In all models, the upper adjacent segment was the most influenced by the implantation and bore the most compensation from the fixed segment. For Type 2 lumbar, the L4-L5 Coflex effectively reduced the disc pressure and annulus fibrosis stress in adjacent segments compared to the L4-L5 Fusion. Similarly, the L4-L5 Coflex offered considerable advantages in preserving the biomechanical properties of adjacent segments for Type 1 lumbar. For Type 4 lumbar, the L4-L5 Coflex did not have superiority over the L4-L5 Fusion, resulting in a greater increase in range of motion at adjacent segments in flexion and extension. The difference between the two fixations was not apparent in Type 3 lumbar. Compared to the single-level Fusion, the changes in motion and mechanics of the lumbar increased after both the double-level Coflex + Fusion and Fusion + Fusion fixations, while the differences between two double-level fixation methods on adjacent segments of the four lumbar models were similar to that of the single-level fixation.

CONCLUSION

Type 3 and Type 4 lumbar have good compensatory ability and therefore allow for a wider range of surgical options, whereas surgical options for small lordotic Type 1 and Type 2 lumbar are more limited and severe.

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

PURPOSE

This study aims to evaluate complications, clinical outcomes, and radiographic results following Coflex implantation.

METHODS

We 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.

RESULTS

66 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.

CONCLUSION

Our 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.

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.

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 comparative analysis of effects of dynamic and rigid fusion on lumbar motion with different sagittal parameters: An in vitro study

Background: Although the management of the lumbar disease is highly dependent on the severity of the patient’s condition, optimal surgical techniques to reduce the risk of adjacent degeneration disease (ADS) remain elusive. Based on in vitro biomechanical tests of the cadaver spine, this study aimed to comparatively analyze the kinematic responses of the spine with dynamic and rigid fixations (i.e., Coflex fixation and posterolateral fusion) after single-or double-level lumbar fusion in daily activities.

Methods: Six human lumbar specimens (L1-S1) were selected for this experiment, and the sagittal parameters of each lumbar specimen were measured in the 3D model. The specimens were successively reconstructed into five groups of models: intact model, single-level L4-5 Coflex fixation model, single-level L4-5 Fusion (posterior pedicle screw fixation) model, double-level L4-5 Coflex + L5-S1 Fusion model; and double-level L4-5 Fusion + L5-S1 Fusion model. The pure moment was applied to the specimen model to simulate physiological activities in daily life through a custom-built robot testing device with an optical tracking system.

Results: For single-level lumbar fusion, compared to the traditional Fusion fixation, the Coflex dynamic fixation mainly restricted the extension of L4-L5, partially retained the range of motion (ROM) of the L4-L5 segment, and reduced the motion compensation of the upper adjacent segment. For the double-level lumbar fixation, the ROM of adjacent segments in the Coflex + Fusion was significantly decreased compared to the Fusion + Fusion fixation, but there was no significant difference. In addition, PT was the only sagittal parameter of the preoperative lumbar associated with the ROM under extension loading. The Coflex fixation had little effect on the original sagittal alignment of the lumbar spine.

Conclusion: The Coflex was an effective lumbar surgical technique with a less altering kinematic motion of the lumbar both at the index segment and adjacent segments. However, when the Coflex was combined with the fusion fixation, this ability to protect adjacent segments remained elusive in slowing the accelerated degradation of adjacent segments.

A novel minimally invasive technique of inter-spinal distraction fusion surgery for single-level lumbar spinal stenosis in octogenarians: a retrospective cohort study

Objective

Surgical treatment of lumbar spinal stenosis (LSS) in octogenarians (patients aged ≥ 80 years) has been a challenge. Inter-spinal distraction fusion (ISDF)—a minimally invasive procedure—was used for treating LSS in octogenarians. This retrospective cohort study aimed to investigate the clinical efficacy and safety of a minimally invasive ISDF technique for LSS in octogenarian patients.

Methods

From April 2015 to April 2019, octogenarian patients who underwent lumbar fusion surgery due to single-segment LSS were included. The patients were grouped into the ISDF group and posterior lumbar interbody fusion (PLIF) group based on the type of surgery. Clinical outcomes were evaluated using scores of the visual analog pain scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedics Association (JOA) scale. Radiographs were assessed for the intervertebral angle (IA), lumbar lordosis (LL), and posterior disc height (PDH). After 2 years postoperatively, all patients underwent computed tomography (CT) to evaluate the fusion condition. Perioperative data and related complications were recorded.

Results

Sixty-two patients were included (mean age: 82.22 ± 1.95 years). The ISDF and the PLIF groups had 34 and 28 patients, respectively. The average follow-up time was 2.1 ± 0.25 years. There was no significant difference in VAS, ODI, JOA, and PDH scores between both groups preoperatively and at each postoperative time-point. The IA and LL showed significant differences between both groups after surgery (p < 0.05). The postoperative IA in the ISDF group were significantly lower than the preoperative values, while that in the PLIF group were markedly increased. The PLIF group had an increased LL compared with that preoperatively (p < 0.05), while the LL in the ISDF did not significantly change. The operative time, blood loss, hospital stay time, and the rate of perioperative complications of the ISDF group were significantly lower than those of the PLIF group (p < 0.05). There was no significant difference in the fusion rates between both groups.

Conclusion

ISDF surgery is a viable method for octogenarian patients with LSS that provides a similar clinical efficacy, shorter operative time, less blood loss, shorter hospital stay time, and fewer complications, compared to the PLIF surgery.