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

Abstract

Purpose

Prospective evaluation of radiographic fusion outcomes in patients receiving instrumented posterior arthrodesis of the lumbar spine using a minimally invasive interspinous fixation device.

Patients and Methods

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.

Results

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.

Conclusion

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.

Keywords:

• interspinous fusion
• fusion grading scale
• ligament sparing
• spinal stenosis

Acknowledgments

The authors gratefully acknowledge the contributions of Dr. Douglas Beall, Dr. Reade De Leacy, and Dr. Edward Yoon in conducting the radiographic assessments of patients’ scans according to the new interspinous fusion rubric.

Disclosure

Dr Thomas Hedman reports personal fees from Spinal Simplicity LLC, during the conduct of the study. Mr Adam J Rogers is an employee of Spinal Simplicity LLC, outside the submitted work. In addition, Mr Adam J Rogers reports various patents issued to Spinal Simplicity with no royalties and other payments for these patents. Dr Gabriel P Jasper is part of the medical advisory of and owns stock options from Spinal Simplicity, outside the submitted work. Dr Douglas P Beall reports grants from Medtronic, Medical Metrics, Avanos, Relievant, Boston Scientific, Stryker, Sollis Pharmaceuticals, Simplify Medical, Lenoss Medical, Spine BioPharma, Eliem Therapeutics, Smart Soft, Tissue Tech, Vivex, Stratus Medical, Restorative Therapies, Kolon TissueGene, Companion Spine, DiscGenics; personal fees from Medtronic, Spineology, Merit Medical, Johnson & Johnson, IZI, Techlamed, Peterson Enterprises, Medical Metrics, Avanos, Boston Scientific, Sollis Pharmaceuticals, Simplify Medical, Stryker, Lenoss Medical, Spine BioPharma, Piramal, ReGelTec, Nanofuse, Spinal Simplicity, Pain Theory, Spark Biomedical, Micron Medical Corp, Bronx Medical, Smart Soft, Tissue Tech, RayShield, Stayble, Thermaquil, Vivex, Stratus Medical, Genesys, Abbott, Eliquence, SetBone Medical, Amber Implants, Cerapedics, Neurovasis, Varian Medical Systems, Companion Spine, DiscGenics, Discure, SpinaFX, PainTEQ, during the conduct of the study. The authors report no other conflicts of interest in this work.