Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Classifying invasiveness of minimally invasive spine surgery (MISS) techniques: toward a standardized system  (116235)

Roger Hartl 1 , Rachel Bratescu 1 , Noah Willett 1 2 , Chibuikem Ikwuegbuenyi 1 , Samuel Cho 3 , Gianluca Vadala' 4 , Hai Le 5 , Hardeep Singh 6 , Xudong Joshua Li 7 , Juan P. Cabrera 8 , Luca Ambrosio 4 , Patrick Hsieh 9 , Sathish Muthu 10 11 , Zhuojing Luo 12 , Christopher Martin 13 , Veranis Sotiris 14 , Amit Jain 15 , Viswanadha Arun-Kumar 16 , Stipe Corluka 17 , Philip Louie 18 , Jason Cheung 19 , Ashish Diwan 20 , Xiaolong Chen 20 , Yabin Wu 21 , Timothy S Yoon 22
  1. Department of Neurological Surgery, Och Spine at New York Presbyterian Hospital, Weill Cornell Medicine, New York, United States
  2. Weill Cornell Medicine, New York, NEW YORK, United States
  3. Department of Orthopaedic Surgery, Icahn School of Medicine at Mount Sinai, New York, United States
  4. Research Unit of Orthopaedic and Trauma Surgery, Department of Orthopaedic and Trauma Surgery, Universita Campus Bio-Medico di Roma, Rome, Italy
  5. Department of Orthopaedic Surgery, University of California Davis, Sacramento, California, United States
  6. Department of Orthopedic Surgery, University of Connecticut Health Center, Comprehensive Spine Center, Farmington, CT, United States
  7. Department of Orthopaedic Surgery, University of Virginia School of Medicine, Chartottesville, VA, United States
  8. Division of Neurosurgery, Hospital Clinico Regional de Concepcion, Concepcion, Chile
  9. Neurosurgery Spine Program, University of southern california, Los Angeles, California, United States
  10. Orthopaedic Research Group, Coimbatore, Tamil Nadu, India
  11. Orthopaedic Research Group, Coimbatore, Tamil Nadu, India
  12. Department of Orthopaedic Surgery, Xijing Hospital, Xijing, China
  13. Department of Orthopedic Surgery, Univeristy of Minnesota, Minneapolis, Minnesota, United States
  14. Department of Neurosurgery, General Air Force General Staff Hospital Athens, Athens, Greece
  15. Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD, United States
  16. Reva Spine Centre, Visakhapatnam, India
  17. Spinal Surgery Division, Department of Traumatology, University Hospital Centre Sestre Milosrdnice, Zagreb, Croatia
  18. Center for Neurosciences and Spine, Department of Neurosurgery, Virgina Mason Franciscan Health, Seattle, Washington, United States
  19. Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, China
  20. St. George Hospital, Department of Orthopaedic Surgery, Spine Service, University of New South Wales, Sydney, Australia
  21. Research Department, AO Spine, AO Foundation, Davos, Switzerland
  22. Department of Orthopedic Surgery, Emory University, Atlanta, GA, United States

Introduction 

Minimally invasive spine surgery (MISS) is well-established with various techniques available for treating degenerative spine diseases. However, no standardized classification exists to assess the relative invasiveness of different MISS approaches. This study aimed to identify key surgical factors that determine invasiveness and develop a standardized scale for ranking MISS procedures. 

Methods 

An expert panel of international surgeons who specialize in MISS were recruited to participate in this study. The study was divided into two stages. The first stage focused on defining the factors that influence the invasiveness of MISS and developing a grading scale to rank the relative invasiveness for each factor. The second stage involved using this scale to survey participating surgeons on the invasiveness of surgical approaches to refine the grading scale further and gain consensus.   

Results 

The first stage was completed over the course of 8 months and 7 meetings. The proposed factors included procedure time, number of approaches, blood loss, pedicle screw placement, muscle dissection, anesthesia, number of levels, fusion technique, and whether it was a revision procedure. Each factor was graded on a scale of 0 to 2, with 0 being the least invasive and 2 being the most invasive. Using blood loss as an example, minimal (<50 mL) loss was assigned 0 points, <200 mL was assigned 1 point, and >200 mL was assigned 2 points. Twenty international surgeons were recruited to complete the second stage, which occurred over 2 months and 2 meetings. The procedures consisted of endoscopic 1-level discectomy (mean = 0.79 points), tubular 1-level discectomy (mean = 1.95 points), open 1-level discectomy (mean = 2.89 points),1-level lateral lumbar interbody fusion (mean = 3.89 points), open 1-level laminectomy (mean = 4.79 points), MISS 1-level transforaminal interbody fusion (TLIF) (mean = 5.16 points), open 3-level laminectomy (mean = 6 points), 1-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation (mean = 7.16 points), MISS 2-level TLIF (mean = 8 points), open 1-level TLIF (mean = 8.05 points), and thoracic to pelvis fixation with a 1-level TLIF (mean = 13.58 points). 

Discussion 

This study established an invasiveness classification grading scale for procedures based on 9 factors. Using the developed grading scale, an endoscopic 1-level discectomy was the least invasive procedure graded, and a thoracic to pelvis fixation the most invasive. Further validation of this classification system is needed through both clinical studies to assess its practical utility and a Delphi study to establish consensus on procedure rankings. 

674d37c8c93e7-Table.png

 

 

 

674d37c8c93e7-Graph.png