Defining modern iatrogenic flatback syndrome: examination of segmental lordosis in short lumbar fusion patients undergoing thoracolumbar deformity correction

Bassel G Diebo; Manjot Singh; Mariah Balmaceno-Criss; Mohammad Daher; Lawrence G Lenke; Christopher P Ames; Douglas C Burton; Stephen M Lewis; Eric O Klineberg; Renaud Lafage; Robert K Eastlack; Munish C Gupta; Gregory M Mundis; Jeffrey L Gum; Kojo D Hamilton; Richard Hostin; Peter G Passias; Themistocles S Protopsaltis; Khaled M Kebaish; Han Jo Kim; Christopher I Shaffrey; Breton G Line; Praveen V Mummaneni; Pierce D Nunley; Justin S Smith; Jay Turner; Frank J Schwab; Juan S Uribe; Shay Bess; Virginie Lafage; Alan H Daniels; International Spine Study Group (ISSG)

doi:10.1007/s00586-024-08531-z

Defining modern iatrogenic flatback syndrome: examination of segmental lordosis in short lumbar fusion patients undergoing thoracolumbar deformity correction

Eur Spine J. 2024 Dec;33(12):4627-4635. doi: 10.1007/s00586-024-08531-z. Epub 2024 Oct 23.

Authors

Bassel G Diebo¹, Manjot Singh¹, Mariah Balmaceno-Criss¹, Mohammad Daher¹, Lawrence G Lenke², Christopher P Ames³, Douglas C Burton⁴, Stephen M Lewis⁵, Eric O Klineberg⁶, Renaud Lafage⁷, Robert K Eastlack⁸, Munish C Gupta⁹, Gregory M Mundis⁸, Jeffrey L Gum¹⁰, Kojo D Hamilton¹¹, Richard Hostin¹², Peter G Passias¹³, Themistocles S Protopsaltis¹³, Khaled M Kebaish¹⁴, Han Jo Kim¹⁵, Christopher I Shaffrey¹⁶, Breton G Line¹⁷, Praveen V Mummaneni³, Pierce D Nunley¹⁸, Justin S Smith¹⁹, Jay Turner²⁰, Frank J Schwab⁷, Juan S Uribe²⁰, Shay Bess¹⁷, Virginie Lafage⁷, Alan H Daniels²¹; International Spine Study Group (ISSG)

Affiliations

¹ Department of Orthopedic Surgery, Warren Alpert Medical School of Brown University, 1 Kettle Point Ave, East Providence, RI, 02914, USA.
² Department of Orthopedic Surgery, Columbia University Medical Center, New York, NY, USA.
³ Department of Neurological Surgery, University of California, San Francisco, CA, USA.
⁴ Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, KS, USA.
⁵ Department of Orthopedics, University of Toronto, Toronto, Canada.
⁶ Department of Orthopedic Surgery, University of Texas McGovern Medical School, Houston, TX, USA.
⁷ Department of Orthopedic Surgery, Northwell Health, Lenox Hill Hospital, New York, NY, USA.
⁸ Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, San Diego, CA, USA.
⁹ Department of Orthopedic Surgery, Washington University, St. Louis, MO, USA.
¹⁰ Norton Leatherman Spine Center, Louisville, KY, USA.
¹¹ Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
¹² Southwest Scoliosis and Spine Institute, Plano, TX, USA.
¹³ Department of Orthopedics, New York University Langone Orthopedic Hospital, New York, NY, USA.
¹⁴ Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
¹⁵ Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA.
¹⁶ Department of Neurosurgery, Duke Spine Division, Durham, NC, USA.
¹⁷ Department of Spine Surgery, Denver International Spine Center, Denver, CO, USA.
¹⁸ Spine Institute of Louisiana, Shreveport, LA, USA.
¹⁹ Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, VA, USA.
²⁰ Barrow Brain and Spine, Phoenix, AZ, USA.
²¹ Department of Orthopedic Surgery, Warren Alpert Medical School of Brown University, 1 Kettle Point Ave, East Providence, RI, 02914, USA. alandanielsmd@gmail.com.

PMID: 39443371
DOI: 10.1007/s00586-024-08531-z

Abstract

Purpose: Understanding the mechanism and extent of preoperative deformity in revision procedures may provide data to prevent future failures in lumbar spinal fusion patients.

Methods: ASD patients without prior spine surgery (PRIMARY) and with prior short (SHORT) and long (LONG) fusions were included. SHORT patients were stratified into modes of failure: implant, junctional, malalignment, and neurologic. Baseline demographics, spinopelvic alignment, offset from alignment targets, and patient-reported outcome measures (PROMs) were compared across PRIMARY and SHORT cohorts. Segmental lordosis analyses, assessing under-, match, or over-correction to segmental and global lordosis targets, were performed by SRS-Schwab coronal curve type and construct length.

Results: Among 785 patients, 430 (55%) were PRIMARY and 355 (45%) were revisions. Revision procedures included 181 (23%) LONG and 174 (22%) SHORT corrections. SHORT modes of failure included 27% implant, 40% junctional, 73% malalignment, and/or 28% neurologic. SHORT patients were older, frailer, and had worse baseline deformity (PT, PI-LL, SVA) and PROMs (NRS, ODI, VR-12, SRS-22) compared to primary patients (p < 0.001). Segmental lordosis analysis identified 93%, 88%, and 62% undercorrected patients at LL, L1-L4, and L4-S1, respectively. SHORT patients more often underwent 3-column osteotomies (30% vs. 12%, p < 0.001) and had higher ISSG Surgical Invasiveness Score (87.8 vs. 78.3, p = 0.006).

Conclusions: Nearly half of adult spinal deformity surgeries were revision fusions. Revision short fusions were associated with sagittal malalignment, often due to undercorrection of segmental lordosis goals, and frequently required more invasive procedures. Further initiatives to optimize alignment in lumbar fusions are needed to avoid costly and invasive deformity corrections.

Level of evidence: IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Keywords: Adult spinal deformity; Mode of failure; Revision; Sagittal malalignment; Segmental lordosis.

MeSH terms

Adult
Aged
Female
Humans
Iatrogenic Disease
Lordosis* / diagnostic imaging
Lordosis* / surgery
Lumbar Vertebrae* / diagnostic imaging
Lumbar Vertebrae* / surgery
Male
Middle Aged
Reoperation / methods
Reoperation / statistics & numerical data
Spinal Fusion* / adverse effects
Spinal Fusion* / methods
Thoracic Vertebrae* / diagnostic imaging
Thoracic Vertebrae* / surgery