Midterm Clinical and Radiologic Outcomes after Percutaneous Interspinous Spacer Treatment for Neurogenic Intermittent Claudication

Clinical and radiological outcomes following insertion of a novel removable percutaneous interspinous process spacer: an initial experience

PURPOSE

To evaluate clinical and radiological outcomes of a series of patients treated with a removable percutaneous interspinous process spacer (IPS) (LobsterProject® Techlamed®) for symptomatic degenerative lumbar spinal stenosis (DLSS).

METHODS

All patients treated in two centres with this IPS during 2019 were retrospectively reviewed. Procedures were performed under deep sedation or general anaesthesia by two interventional radiologists. Patients were clinically evaluated before intervention and at 3-month follow-up with Visual Analog Scales for pain (VAS), Oswestry Disability Index (ODI) and radiologically with MRI or CT scans. Neural foramina were independently measured for each patient on pre- and post-procedural CT scans by two radiologists.

RESULTS

Fifty-nine patients were treated in the selected period of which fifty-eight had complete documentation (mean age 71.2 ± 9.2 years [55-92], 32 males, 26 females). Forty-eight interventions were performed under deep sedation and ten under general anaesthesia, without procedural complications. Clinical follow-up at 3 months showed a significant reduction of pain (VAS from 83 ± 9 to 29 ± 19, - 65%; p < 0.001) and an improvement in functional outcomes (ODI from 31 ± 12 to 13 ± 10%, - 58%; p < 0.001). There was one case of unsatisfactory positioning post procedure, two cases of posterior migration at 3-month follow-up and one case of spinous process fracture. Mean neural foramina area increased from 77 ± 23 to 95 ± 27 mm² (+ 26%; p < 0.001) with very good inter-observer reliability (Cronbach's alpha = 0.899).

CONCLUSION

Percutaneous minimally invasive insertion of a removable IPS device demonstrates a favourable safety profile, good clinical outcomes at 3 months, and apparent anatomical increase in foraminal dimensions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05203666-Release Date: 21^st January 2022, retrospectively registered.

The use of minimally invasive interspinous process devices for the treatment of lumbar canal stenosis: a narrative literature review

Minimally invasive interspinous process devices (IPD), including interspinous distraction devices (IDD) and interspinous stabilizers (ISS), are increasingly utilized for treating symptomatic lumbar canal stenosis (LCS). There is ongoing debate around their efficacy and safety over traditional decompression techniques with and without interbody fusion (IF). This study presents a comprehensive review of IPD and investigates if: (I) minimally invasive IDD can effectively substitute direct neural decompression and (II) ISS are appropriate substitutes for fusion after decompression. Articles published up to 22^nd January 2020 were obtained from PubMed search. Relevant articles published in the English language were selected and critically reviewed. Observational studies across different IPD brands consistently show significant improvements in clinical outcomes and patient satisfaction at short-term follow-up. Compared to non-operative treatment, mini-open IDD was had significantly greater quality of life and clinical outcome improvements at 2-year follow-up. Compared to open decompression, mini-open IDD had similar clinical outcomes, but associated with higher complications, reoperation risks and costs. Compared to open decompression with concurrent IF, ISS had comparable clinical outcomes with reduced operative time, blood loss, length of stay and adjacent segment mobility. Mini-open IDD had better outcomes over non-operative treatment in mild-moderate LCS at 2-year follow-up, but had similar outcomes with higher risk of re-operations than open decompression. ISS with open decompression may be a suitable alternative to decompression and IF for stable grade 1 spondylolisthesis and central stenosis. To further characterize this procedure, future studies should focus on examining enhanced new generation IPD devices, longer-term follow-up and careful patient selection.

Successful use of percutaneous interspinous spacers and adjunctive spinoplasty in a 9 year cohort of patients

Purpose

Lumbar spinal canal stenosis and lumbar spinal foraminal stenosis are common, degenerative pathologies which can result in neurogenic claudication and have a negative impact on function and quality of life. Percutaneous interspinous devices (PIDs) are a recently-developed, minimally-invasive, alternative treatment option. This study details a 9 year single-centre experience with PIDs and examines the complementary use of spinous process augmentation (spinoplasty) to reduce failure rates.

Methods

A retrospective cohort assessment of 800 consecutive patients who presented to a specialized spine hospital was performed with 688 receiving treatment. Inclusion was based on high-grade stenosis, failure of conservative management and electromyography. 256 had a PID alone while 432 had concurrent polymethyl methacrylate (PMMA) augmentation of the adjacent spinous processes. The patients were followed up at 3 and 12 months using the Zurich Claudication Questionnaire (ZCQ) and Oswestry Disability Index (ODI).

Results

Both groups showed marked improvement in the patients’ ZCQ scores (3.2 to 1.3) and ODI scores (32 to 21), with strong satisfaction results (1.7). The symptom recurrence rate from complications for the group which received concurrent spinous process augmentation was reduced when compared with the PID alone cohort (<1% vs 11.3%).

Conclusion

This study demonstrates the efficacy of percutaneous interspinous devices in treating lumbar spinal stenosis. It also provides evidence that concurrent spinous process augmentation reduces the rate of symptom recurrence.

Decompression Surgery versus Interspinous Devices for Lumbar Spinal Stenosis: A Systematic Review of the Literature

In this retrospective review study, the authors systematically reviewed the literature to elucidate the efficacy and complications associated with decompression and interspinous devices (ISDs) used in surgeries for lumbar spinal stenosis (LSS). LSS is a debilitating condition that affects the lumbar spinal cord and spinal nerve roots. However, a comprehensive report on the relative efficacy and complication rate of ISDs as they compare to traditional decompression procedures is currently lacking. The PubMed database was queried to identify clinical studies that exclusively investigated decompression, those that exclusively investigated ISDs, and those that compared decompression with ISDs. Only prospective cohort studies, case series, and randomized controlled trials that evaluated outcomes using the Visual Analog Scale (VAS), Oswestry Disability Index, or Japanese Orthopedic Association scores were included. A random-effects model was established to assess the difference between preoperative and the 1–2-year postoperative VAS scores between ISD surgery and lumbar decompression. This study included 40 papers that matched our criteria. Twenty-five decompression-exclusive clinical trials with 3,386 patients and a mean age of 68.7 years (range, 31–88 years) reported a 2.2% incidence rate of dural tears and a 2.6% incidence rate of postoperative infections. Eight ISD-exclusive clinical trials with 1,496 patients and a mean age of 65.1 (range, 19–89 years) reported a 5.3% incidence rate of postoperative leg pain and a 3.7% incidence rate of spinous process fractures. Seven studies that compared ISDs and decompression in 624 patients found a reoperation rate of 8.3% in ISD patients vs. 3.9% in decompression patients; they also reported dural tears in 0.32% of ISD patients vs. 5.2% in decompression patients. A meta-analysis of the randomized controlled trials found that the differences in preoperative and postoperative VAS scores between the two groups were not significant. Both decompression and ISD interventions are unique surgical interventions with different therapeutic efficacies and complications. The collected studies do not consistently demonstrate superiority of either procedure over the other but understanding the differences between the two techniques can help tailor treatment regimens for patients with LSS.

MRI evaluation of dural sac enlargement by interspinous process spacers in patients with lumbar spinal stenosis: Does it play a role in the long term?

BACKGROUND

To investigate dural sac enlargements and spinal alignments in patients who underwent indirect decompression with interspinous spacers.

METHODS

The subjects were 20 patients who underwent indirect decompression using an interspinous spacer (X-STOP) without laminectomy. Of these 20 patients, 1 patient underwent implant removal surgery 1 month after X-STOP surgery and two patients dropped out. Ultimately, 17 patients were included in this study. MRI and X-ray images were investigated before surgery, 1 week after surgery, 3 months after surgery, and 2 years after surgery.

RESULTS

On MRI, the mean cross-sectional areas of the dural sac were 52.7 mm² before surgery, 73.2 mm² 1 week after surgery, 62.4 mm² 3 months after surgery, and 58.3 mm² 2 years after surgery. There was a significant 37% increase at 1 week postoperatively compared with that before surgery, but there were no significant differences between 3 months postoperatively and 2 years postoperatively. The disc angle in an extension posture was significantly decreased at 1 week after surgery compared with that before surgery, but there were no significant differences between before surgery, 3 months after surgery, and 2 years after surgery.

CONCLUSIONS

The interspinous process spacer increased the dural sac area by 37% 1 week after surgery, but the enlargement was not maintained at 3 months or 2 years after surgery. The use of interspinous process spacers produced an enlargement of the dural sac by limiting extension of the stenotic level only. However, its effect diminished 2 years after surgery.

Axial loading during MRI reveals insufficient effect of percutaneous interspinous implants (Aperius™ PerCLID™) on spinal canal area

PURPOSE

To evaluate the effect on the spinal canal at the treated and adjacent level(s), in patients treated for lumbar spinal stenosis (LSS) with percutaneous interspinous process device (IPD) Aperius™ or open decompressive surgery (ODS), using axial loading of the spine during MRI (alMRI).

MATERIALS

Nineteen LSS patients (mean age 67 years, range 49-78) treated with IPDs in 29 spine levels and 13 LSS patients (mean age 63 years, range 46-76) operated with ODS in 22 spine levels were examined with alMRI pre- and 3 months postoperatively. Radiological effects were evaluated by measuring the dural sac cross-sectional area (DSCSA) and by morphological grading of nerve root affection.

RESULTS

For the IPD group, no DSCSA increase was observed at the operated level (p = 0.42); however, a decrease was observed in adjacent levels (p = 0.05). No effect was seen regarding morphological grading (operated level: p = 0.71/adjacent level: p = 0.94). For the ODS group, beneficial effects were seen for the operated level, both regarding DSCSA (p < 0.001) and for morphological grading (p < 0.0001). No changes were seen for adjacent levels (DSCSA; p = 0.47/morphological grading: p = 0.95). Postoperatively, a significant difference between the groups existed at the operated level regarding both evaluated parameters (p < 0.003).

CONCLUSIONS

With the spine imaged in an axial loaded position, no significant radiological effects of an IPD could be detected postoperatively at the treated level, while increased DSCSA was displayed for the ODS group. In addition, reduced DSCSA in adjacent levels was detected for the IPD group. Thus, the beneficial effects of IPD implants on the spinal canal must be questioned. These slides can be retrieved under Electronic Supplementary Material.