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Duo implant filled and placed in disc space. Axial view.

The goals of the lateral interbody fusion procedure are to:

  • Place a large implant for immediate structural support, restore stability to the diseased segment, and indirectly decompress diseased segment(s)

  • Perform the procedure through the smallest access possible to avoid trauma to the psoas muscle and reduce compression/stretching of the neural structures to minimize the risk of neurological deficits following surgery

  • Efficiently complete the procedure to reduce the duration of time the neural structures are compressed/stretched,
    thereby mitigating the risk of neurological deficits following surgery


The Duo™ procedure represents the latest advancements in lateral lumbar interbody fusion (LLIF). The system offers a unique implant design that expands to up to 30 mm in width, and the procedure is performed through an 18 mm-wide Portal Tube—a much smaller access window compared to traditional LLIF procedures that utilize a bladed retractor. In addition, the Duo procedure targets the midpoint of the affected disc space and eliminates the need to retract and toe blades—all of which add efficiency and ease of use to the procedure. 

Duo retraction compared to traditional lateral bladed retractor requirements

The Duo procedure is designed to conserve anatomy and increase efficiency compared to traditional LLIF procedures, resulting in several potential benefits to you, your patient, and the hospital. Some of these benefits include:

  • Reduced neurologic deficits1,2 
  • Decreased operative time by up to 33%3 
  • Reduced blood loss3 
  • Shorter hospital stay by up to 37% / 1.3 days3
  • Decreased hospital costs4 
  • Reduced intraoperative and wound complications2,4 


The Spineology RaDical Study is being conducted to assess short-term and long-term outcomes in patients treated with the Duo System. This prospective, multi-site evaluation of 200 patients is Institutional Review Board (IRB)-approved and captures both subjective and objective patient data in a real-world, adult population. To view the latest data from the RaDical Post-Market Study, click here

The Duo™ procedure employs Spineology’s proprietary Duo interbody fusion implant and instrumentation system. To learn more about the Duo system, click here.

Link to Duo product page



1. Nunley P, Hill C, Malloy J, Strenge B, Stone M. A Prospective, In-Depth Analysis of Perioperative Anterior Thigh Symptoms Associated with a Direct Lateral Access Approach for Lumbar Interbody Fusion. Presentation at: Society of Minimally Invasive Spine Surgeons Annual Forum 31 Oct – 2 Nov 2019; Las Vegas NV.

 2. Joseph et al. Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systemic review of the literature.  Neurosurgery Focus 39 (4)E4, 2015. 

3. Meta-analysis of multiple references compared to RaDical Post Market Study Data from the first 115 patients.

  • Cummock MD, Vanni S, Levi AD, Yu Y, and Wang MY: An analysis of postoperative thigh symptoms after minimally invasive transpsoas lumbar interbody fusion. J Neurosurg Spine 15:11- 18, 2011 
  • Campbell PG, Nunley PD, et al: Short-term outcomes of lateral lumbar interbody fusion without decompression for the treatment of symptomatic degenerative spondylolisthesis at L4–5. Neurosurgical Focus 44 (1):E6, 2018 
  • Youssef JA, et al: Minimally Invasive Surgery: Lateral Approach Interbody Fusion. SPINE Volume 35, Number 26S, pp S302–S311 
  • Ozgur BM, et al: Extreme Lateral Interbody Fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion. The Spine Journal 6 (2006) 435–443
  • Knight RQ, et al: Direct Lateral Lumbar Interbody Fusion for Degenerative Conditions - Early Complication Profile. J Spinal Disord Tech 2009;22:34–37
  • Du JY et al: Lateral Lumbar Interbody Fusion with Unilateral Pedicle Screw Fixation for the Treatment of Adjacent Segment Disease: A Preliminary Report. Journal of Spine Surgery, 2017; 3(3):330-337 
  • Grim BD, Leas DP, Poletti SC, Johnson DR: Postoperative Complications within the First Year After Extreme Lateral Interbody Fusion: Experience of the First 108 Patients. Clin Spine Surg, Volume 29, Number 3, April 2016
  • Kepler CK, Sharma AK, Huang RC: Lateral Transpsoas Interbody Fusion (LTIF) With Plate Fixation and Unilateral Pedicle Screws: A Preliminary Report. Journal of Spinal Disorders & Techniques: August 2011 - Volume 24, Issue 6, p 363–367 
  • Lee YS, Kim YB, Park SW, Chung C: Comparison of Transforaminal Lumbar Interbody Fusion with Direct Lumbar Interbody Fusion: Clinical and Radiological Results. J Korean Neurosurg Soc 56 (6) : 469-474, 2014 
  • Marchi et al: Radiographic and Clinical Evaluation of Cage Subsidence after Standalone Lateral Interbody Fusion. J Neurosurgery Spine 19: 110-118, 2013 
  • Na YC et al: Initial Clinical Outcomes of Minimally Invasive Lateral Lumbar Interbody Fusion in Degenerative Lumbar Disease: A Preliminary Reprot on the Experience of a Single Institusion with 30 Cases. Korean J Spine 9((3): 187-192, 2012 
  • Nunley P, Sandu F, Frank K, Stone M: Neurological Complications after Lateral Transpsoas Approach to Anterior Interbody Fusion with a Novel Flat-Blade Spine-Fixed Retractor. Biomed Research International, Volume 2016, Article ID 8450712

4. Data on file at Spineology Inc.