Tag: motion preservation

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Utilization of robotic pars repair for early return to activity in adolescents with symptomatic spondylolysis

J Neurosurg Spine 44:349–354, 2026

This case series from a tertiary academic spine center reports outcomes of robot-assisted percutaneous pars repair in nine adolescents with symptomatic lumbar spondylolysis who failed conservative management. The authors describe a single–midline incision technique using CT-based robotic guidance and a single lagged transdefect screw, detailing operative workflow, implant sizes, and a standardized postoperative rehabilitation protocol.

Results show most patients returned to preinjury or higher activity within months, with low complication rates and radiographic evidence of union in those who obtained CT follow-up. The authors conclude that minimally invasive robotic pars repair is a viable option after failed nonoperative care and advocate timely surgical consultation to potentially accelerate return to sport and avoid progressive spondylolisthesis.

Clinical problem Symptomatic lumbar pars interarticularis fractures (spondylolysis) are a common cause of adolescent low-back pain; nonoperative care with activity modification is standard first-line treatment.

Nonunion risk Despite conservative management, about 20% of patients may progress to symptomatic nonunion, and some can later develop spondylolisthesis that may require fusion.

Study aim Robotic surgical guidance was used to enable percutaneous pars screw placement; the series reports the largest cohort of adolescents treated with robot-assisted pars repair to date.

Design & cohort Retrospective review of a prospectively collected database identified 9 adolescents/young adults (13–25 years) treated with a single-screw pars repair technique.

Technique Using Excelsius robotic planning/registration and intraoperative 3D imaging, bilateral screw trajectories were planned to converge so bilateral pars screws could be placed through a single 1–2 cm midline incision; compression was achieved via a “lag-by-technique” preparation without direct pars visualization/grafting.

Postop protocol Patients walked only for 2 weeks, then added stationary biking for 2 weeks, followed by 4 weeks of sport-directed physical therapy; if tolerated symptom-free, they were cleared for activity (cleared to begin return-to-sport training at 4 weeks).

Outcomes Mean preop activity cessation at consultation was 8.6 ± 10.6 months; at mean follow-up 11.4 ± 9.1 months, 78% had returned to baseline activity or were cleared to return to sport.

Safety/efficacy conclusion Robot-assisted pars repair was reported as a safe, effective option after failed nonoperative care, enabling return to activity in as little as 8 weeks; a single lag-style screw may be clinically effective compared with prior open debridement/bone-grafting approaches.

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The First Grade III Lumbar Spondylolisthesis Treated With the Novel 360° Artificial Disc/Artificial Facet Replacement Solution

Int J Spine Surg 2025, 19 (4) 362-369

This case report describes the first use of a combined 360° motion-preserving surgery—utilizing Prodisc L Artificial Disc and TOPS facet replacement—for grade III lumbar spondylolisthesis, showing rapid pain relief, improved function, and high patient satisfaction, suggesting a potential alternative to spinal fusion for select patients.

• First reported case of grade III lumbar spondylolisthesis treated with a novel 360° motion-preserving solution combining Prodisc L Artificial Disc Replacement and the Premia TOPS System.

• Traditional treatment is spinal fusion, but it reduces motion and can cause adjacent segment disease, especially problematic for younger, active patients.

• The patient, a 36-year-old man with progressive L5-S1 grade III spondylolisthesis and severe disc collapse, had failed conservative therapy and declined fusion.

• Surgery was performed in two stages: anterior artificial disc replacement, followed by posterior facet replacement with the TOPS device.

• Significant improvements were seen in pain, function, and satisfaction, with the patient pain-free and highly satisfied by 3 and 9 months post-op.

• This case suggests the 360° arthroplasty approach may offer a motion-preserving alternative to fusion for high-grade spondylolisthesis.

• Further research and long-term data are needed to confirm safety, durability, and broader effectiveness.

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Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of spondylolisthesis

J Neurosurg Spine 38:115–125, 2023

The purpose of this study was to evaluate the safety and efficacy of a posterior facet replacement device, the Total Posterior Spine (TOPS) System, for the treatment of one-level symptomatic lumbar stenosis with grade I degenerative spondylolisthesis. Posterior lumbar arthroplasty with facet replacement is a motion-preserving alternative to lumbar decompression and fusion. The authors report the preliminary results from the TOPS FDA investigational device exemption (IDE) trial.

METHODS The study was a prospective, randomized controlled FDA IDE trial comparing the investigational TOPS device with transforaminal lumbar interbody fusion (TLIF) and pedicle screw fixation. The minimum follow-up duration was 24 months. Validated patient-reported outcome measures included the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain. The primary outcome was a composite measure of clinical success: 1) no reoperations, 2) no device breakage, 3) ODI reduction of ≥ 15 points, and 4) no new or worsening neurological deficit. Patients were considered a clinical success only if they met all four measures. Radiographic assessments were made by an independent core laboratory.

RESULTS A total of 249 patients were evaluated (n = 170 in the TOPS group and n = 79 in the TLIF group). There were no statistically significant differences between implanted levels (L4–5: TOPS, 95% and TLIF, 95%) or blood loss. The overall composite measure for clinical success was statistically significantly higher in the TOPS group (85%) compared with the TLIF group (64%) (p = 0.0138). The percentage of patients reporting a minimum 15-point improvement in ODI showed a statistically significant difference (p = 0.037) favoring TOPS (93%) over TLIF (81%). There was no statistically significant difference between groups in the percentage of patients reporting a minimum 20-point improvement on VAS back pain (TOPS, 87%; TLIF, 64%) and leg pain (TOPS, 90%; TLIF, 88%) scores. The rate of surgical reintervention for facet replacement in the TOPS group (5.9%) was lower than the TLIF group (8.8%). The TOPS cohort demonstrated maintenance of flexion/extension range of motion from preoperatively (3.85°) to 24 months (3.86°).

CONCLUSIONS This study demonstrates that posterior lumbar decompression and dynamic stabilization with the TOPS device is safe and efficacious in the treatment of lumbar stenosis with degenerative spondylolisthesis. Additionally, decompression and dynamic stabilization with the TOPS device maintains segmental motion.

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Heterotopic ossification and radiographic adjacent-segment disease after cervical disc arthroplasty

J Neurosurg Spine 31:660–669, 2019

Cervical disc arthroplasty (CDA) is an accepted motion-sparing technique associated with favorable patient outcomes. However, heterotopic ossification (HO) and adjacent-segment degeneration are poorly understood adverse events that can be observed after CDA. The purpose of this study was to retrospectively examine 1) the effect of the residual exposed endplate (REE) on HO, and 2) identify risk factors predicting radiographic adjacent-segment disease (rASD) in a consecutive cohort of CDA patients.

METHODS A retrospective cohort study was performed on consecutive adult patients (≥ 18 years) who underwent 1- or 2-level CDA at the University of Calgary between 2002 and 2015 with > 1-year follow-up. REE was calculated by subtracting the anteroposterior (AP) diameter of the arthroplasty device from the native AP endplate diameter measured on lateral radiographs. HO was graded using the McAfee classification (low grade, 0–2; high grade, 3 and 4). Change in AP endplate diameter over time was measured at the index and adjacent levels to indicate progressive rASD.

RESULTS Forty-five patients (58 levels) underwent CDA during the study period. The mean age was 46 years (SD 10 years). Twenty-six patients (58%) were male. The median follow-up was 29 months (IQR 42 months). Thirty-three patients (73%) underwent 1-level CDA. High-grade HO developed at 19 levels (33%). The mean REE was 2.4 mm in the high-grade HO group and 1.6 mm in the low-grade HO group (p = 0.02). On multivariable analysis, patients with REE > 2 mm had a 4.5-times-higher odds of developing high-grade HO (p = 0.02) than patients with REE ≤ 2 mm. No significant relationship was observed between the type of artificial disc and the development of high-grade HO (p = 0.1). RASD was more likely to develop in the lower cervical spine (p = 0.001) and increased with time (p < 0.001). The presence of an artificial disc was highly protective against degenerative changes at the index level of operation (p < 0.001) but did not influence degeneration in the adjacent segments.

CONCLUSIONS In patients undergoing CDA, high-grade HO was predicted by REE. Therefore, maximizing the implant-endplate interface may help to reduce high-grade HO and preserve motion. RASD increases in an obligatory manner following CDA and is highly linked to specific levels (e.g., C6–7) rather than the presence or absence of an adjacent arthroplasty device. The presence of an artificial disc is, however, protective against further degenerative change at the index level of operation.

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Lumbar Total Disc Replacement for Discogenic Low Back Pain

Lumbar Total Disc Replacement for Discogenic Low Back Pain

Spine 2015;40:1873–1881

A prospective, multicenter, randomized, controlled, investigational device exemption (IDE) noninferiority trial.

Objective. The aim of this study was to evaluate the comparative safety and effectiveness of lumbar total disc replacement (TDR) in the treatment of patients with symptomatic degenerative disc disease (DDD) who are unresponsive to nonsurgical therapy.

Summary of Background Data. Lumbar TDR has been used to alleviate discogenic pain and dysfunction while preserving segmental range of motion and restoring stability. There is a paucity of data available regarding the comparative performance of lumbar TDR.

Methods. Patients presenting with symptomatic single-level lumbar DDD who failed at least 6 months of nonsurgical management were randomly allocated (2:1) to treatment with an investigational TDR device (activL1, n=218) or FDA-approved control TDR devices (ProDisc-L or Charité, n=106). The hypothesis of this study was that a composite effectiveness outcome at 2 years in patients treated with activL would be noninferior (15% delta) to that in controls.

Results. The primary composite endpoint of this study was met, which demonstrated that the activL TDR was noninferior to control TDR (P<0.001). A protocol-defined analysis of the primary composite endpoint also confirmed that activL was superior to controls (P=0.02). Radiographic success was higher with activL versus controls (59% vs. 43%; P<0.01). Mean back pain severity improved by 74% with activL and 68% with controls. Oswestry Disability Index scores decreased by 67% and 61% with activL and controls, respectively. Patient satisfaction with treatment was over 90% in both groups at 2 years. Return to work was approximately 1 month shorter (P=0.08) with activL versus controls. The rate of device-related serious adverse events was lower in patients treated with activL versus controls (12% vs. 19%; P=0.13). Surgical reintervention rates at the index level were comparable (activL 2.3%, control 1.9%).

Conclusion. The single-level activL TDR is safe and effective for the treatment of symptomatic lumbar DDD through 2 years.

Level of Evidence: 2

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Occult Spinous Process Fractures Associated With Interspinous Process Spacers

Spine 2011;36:E1080–E1085. DOI: 10.1097/BRS.0b013e318204066a

Biomechanical cadaveric studies have suggested adequate spinous process strength to support placement of interspinous process spacers (IPS). Postoperative spinous process fractures have been reported in one%—to 5.8% of patients in previous series based on routine biplanar radiographic evaluation. However, most fractures occur between the base and midportion of the spinous process in an area that is typically diffi cult to visualize on plain radiographs due to device design.

Methods. All patients underwent preoperative biplanar plain radiographs and computed tomography (CT) of the lumbar spine to confirm anatomy favorable for IPS placement and rule out fracture or spondylolysis. Postoperatively, all patients underwent repeat CT imaging within six months of surgery, biplanar radiographs at two weeks, six weeks, three months, six months, and one year. All studies were reviewed independently by a neuroradiologist and two orthopedic spine surgeons.

Results. Fifty implants (38 L4–5, 12 L3–4) were placed in 38 patients who completed follow-up and were included in final analysis. Three IPS designs were included (34 Medtronic X-STOP titanium, 8 X-STOP PEEK, 8 Lanx Aspen). Postoperative CT revealed 11 nondisplaced spinous process fractures in 11 patients (28.9% of patients, 22% of levels). Five fractures were associated with mild to moderate lumbar back pain and six fractures were asymptomatic. No patient reported a traumatic incident. No fracture was identifiable on plain radiographs. One fracture displaced during follow-up evaluation. Three patients underwent IPS removal and laminectomy. Three fractures healed by CT in one year. Overall, patients with fractures tended toward poorer outcomes by Zurich Claudication Questionnaire (ZCQ) (28.5% vs. 34.8% improvement in symptom severity, P=  0.496; 21.4% vs. 30.7% improvement in physical function, P = 0.199) and tended toward lower satisfaction rates (50% vs. 73.7%, P = 0.24) at one year compared to patients without fracture.

Conclusion. Interspinous process spacer surgery appears associated with a higher rate of early postoperative spinous process fracture than previously reported. In all cases, in this series, plain radiographs were inadequate to identify fractures because all fractures were initially minimal or nondisplaced, many patients were osteopenic, and the metallic wings of the devices often obscured fractures. Moreover, in most patients, fractures were associated with mild or no acute localized pain. This study suggests that unrecognized spinous process fracture may be responsible for a signifi cant number of patients who experience unsatisfactory outcome after IPS surgery. CT imaging is required to identify the vast majority of such fractures.

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