Incremental benefits of circumferential minimally invasive surgery for increasingly frail patients with adult spinal deformity.



Circumferential minimally invasive surgery (cMIS) may provide incremental benefits compared with open surgery for patients with increasing frailty status by decreasing peri- and postoperative complications.


Operative patients with adult spinal deformity (ASD) ≥ 18 years old with baseline and 2-year postoperative data were assessed. With propensity score matching, patients who underwent cMIS (cMIS group) were matched with similar patients who underwent open surgery (open group) based on baseline BMI, C7-S1 sagittal vertical axis, pelvic incidence to lumbar lordosis mismatch, and S1 pelvic tilt. The Passias modified ASD frailty index (mASD-FI) was used to determine patient frailty stratification as not frail, frail, or severely frail. Baseline and postoperative factors were assessed using two-way analysis of covariance (ANCOVA) and multivariate ANCOVA while controlling for baseline age, Charlson Comorbidity Index (CCI) score, and number of levels fused.


After propensity score matching, 170 ASD patients (mean age 62.71 ± 13.64 years, 75.0% female, mean BMI 29.25 ± 6.60 kg/m2) were included, split evenly between the cMIS and open groups. Surgically, patients in the open group had higher numbers of posterior levels fused (p = 0.021) and were more likely to undergo three-column osteotomies (p > 0.05). Perioperatively, cMIS patients had lower intraoperative blood loss and decreased use of cell saver across frailty groups (with adjustment for baseline age, CCI score, and levels fused), as well as fewer perioperative complications (p < 0.001). Adjusted analysis also revealed that compared to open patients, increasingly frail patients in the cMIS group were also more likely to demonstrate greater improvement in 1- and 2-year postoperative scores for the Oswestry Disability Index, SRS-36 (total), EQ-5D and SF-36 (all p < 0.05). With regard to postoperative complications, increasingly frail patients in the cMIS group were also noted to experience significantly fewer complications overall (p = 0.036) and fewer major intraoperative complications (p = 0.039). The cMIS patients were also less likely to need a reoperation than their open group counterparts (p = 0.043).


Surgery performed with a cMIS technique may offer acceptable outcomes, with diminishment of perioperative complications and mitigation of catastrophic outcomes, in increasingly frail patients who may not be candidates for surgery using traditional open techniques. However, further studies should be performed to investigate the long-term impact of less optimal alignment in this population.





Published Version (Please cite this version)


Publication Info

Passias, Peter G, Peter S Tretiakov, Pierce D Nunley, Michael Y Wang, Paul Park, Adam S Kanter, David O Okonkwo, Robert K Eastlack, et al. (2023). Incremental benefits of circumferential minimally invasive surgery for increasingly frail patients with adult spinal deformity. Journal of neurosurgery. Spine. pp. 1–7. 10.3171/2023.2.spine221278 Retrieved from

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Peter Passias

Instructor in the Department of Orthopaedic Surgery

Khoi Duc Than

Professor of Neurosurgery

I chose to pursue neurosurgery as a career because of my fascination with the human nervous system. In medical school, I developed a keen interest in the diseases that afflict the brain and spine and gravitated towards the only field where I could help treat these diseases with my own hands. I focus on disorders of the spine where my first goal is to help patients avoid surgery if at all possible. If surgery is needed, I treat patients using the most advanced minimally invasive techniques available in order to minimize pain, blood loss, and hospital stay, while maximizing recovery, neurologic function, and quality of life. In my free time, I enjoy spending time with my family and friends. I am an avid sports fan and love to eat. I try to stay physically fit by going to the gym and playing ice hockey.


Christopher Ignatius Shaffrey

Professor of Orthopaedic Surgery

I have more than 25 years of experience treating patients of all ages with spinal disorders. I have had an interest in the management of spinal disorders since starting my medical education. I performed residencies in both orthopaedic surgery and neurosurgery to gain a comprehensive understanding of the entire range of spinal disorders. My goal has been to find innovative ways to manage the range of spinal conditions, straightforward to complex. I have a focus on managing patients with complex spinal disorders. My patient evaluation and management philosophy is to provide engaged, compassionate care that focuses on providing the simplest and least aggressive treatment option for a particular condition. In many cases, non-operative treatment options exist to improve a patient’s symptoms. I have been actively engaged in clinical research to find the best ways to manage spinal disorders in order to achieve better results with fewer complications.

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