SpineUniverse Case Study Library

Severe Sagittal Imbalance Correction


A 79-year-old male presented with severe positive sagittal imbalance and neurogenic claudication following a prior L3-S1 decompression and fusion performed by a community neurosurgeon. His primary complaint was a rapid progressive forward posture impairing his ability to walk and perform activities of daily living following his previous surgery.

He was otherwise healthy without a history of neurological disorder.


  • Severe positive sagittal imbalance.
  • No hip or knee contractures.
  • Neurological exam revealed normal lower extremity exam without sensation change or weakness; no pathologic reflexes indicative of myelopathy; no evidence of tremor or signs of neuromuscular disorder such as Parkinson’s disease.

DEXA scan revealed a normal T-score.

Prior Treatment

The patient underwent an unsuccessful surgery by a community spine surgeon with rapid progression of positive sagittal imbalance following surgery. Extensive post-operative physical therapy and attempted bracing were trialed after surgery with no success.

Pre-Treatment Imaging

The MRI of the lumbar spine revealed multilevel spondylosis, L4-L5 spondylolisthesis, and severe residual lateral recess and foraminal stenosis at L3-S1.

Standing scoliosis posteroanterior (PA) imaging includes measurement of lumbar coronal Cobb angle (Figure 1).

Standing scoliosis posteroanterior imaging includes measurement of lumbar coronal Cobb angleFigure 1. Standing scoliosis posteroanterior imaging with measurement of lumbar coronal Cobb angle. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

Standing scoliosis lateral x-ray includes the following measurements: Pelvic Tilt (PT), Pelvic Incidence (PI), Lumbar Lordosis (LL), PI-LL mismatch, Sagittal Vertical Axis (SVA), and T1 Pelvic Angle (TPA) (Figure 2).

Pre-operative standing scoliosis lateral x-rayFigure 2. Standing scoliosis lateral x-ray: PT, PI, LL, PI-LL mismatch, SVA, and TPA. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

Pre-Treatment Clinical Photographs

lateral standing patient photoFigure 3. Lateral photo image of the patient standing. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

anterior photo image of the patient standingFigure 4. Anterior photo image of the patient standing. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.


Failed back surgery with residual stenosis and severe positive sagittal imbalance (SVA 359mm).

Suggest Treatment

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Selected Treatment

Posterior revision L3-S1 decompression, T12-L4 posterior column osteotomies (Grade II), and T3-pelvis fusion with interlaminar stabilization via dual angled construct for proximal junctional kyphosis (PJK) prevention.

Surgeon’s Rationale
Surgical decision-making in cases of severe spinal deformity can be very challenging and requires careful assessment of the patient, surgeon, and institutional factors. In this case, revision decompression was necessary given the severe residual spinal stenosis and neurogenic claudication.

The impressively severely positive SVA required careful assessment and planning for correction. The patient lost his ability to compensate for what was previously moderate deformity before his first surgery. He had no hip or knee contractures, or Parkinson’s disease. Rarely do patients have such severe positive sagittal imbalance with an SVA of >300. This represents a total failure in the patient’s ability to hold themselves upright, and does not always require heroic correction with 3-column osteotomy. Rather, smaller gradual correction may be adequate and may decrease the risk of proximal junctional kyphosis (PJK)/proximal junctional failure (PJF) and neurological complications.

For PJK prevention, an interlaminar flared construct (StabiLink® Dual Lamina, Southern Spine, LLC, Macon, GA) was placed. This strategy may be more robust in some cases than ligamentoplasty, and is easily and rapidly applied.

In the intraoperative photograph below (Figure 5), note the intralaminar fixation construct fixating the upper instrumented vertebra (UIV) to UIV+1 for softer cranial landing.

intraoperative spinal fixationFigure 5. Intraoperative photograph: note the intralaminar fixation construct fixating the UIV to UIV+1 for softer cranial landing. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.


The patient tolerated the procedure exceptionally well with age-appropriate post-operative clinical and radiographic results (Table 1, Figures 6-9).

table 1 postop radiographic alignment parametersTable 1. Pre-operative versus 9-month post-operative radiographic alignment parameters.

post-operative PA x-ray, lumbar coronal Cobb angle measurementFigure 6. Post-operative PA x-ray includes lumbar coronal Cobb angle measurement. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

Post-operative lateral x-ray at 9 months includes SVA, LL, PI, LL-PI mismatch, pelvic tilt, and TPAFigure 7. Post-operative lateral x-ray at 9 months includes PT, PI, LL, PI-LL, and TPA. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

Careful radiographic follow-up is essential to monitor the patient for development of PJK or PJF among other potential complications such as rod failure.

Comparative Pre- and Post-Operative Clinical Photographs

lateral standing pre- and post-operative comparison photosFigure 8. Pre- and post-operative lateral standing photographs. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

anterior standing pre- and post-operative photographsFigure 9. Anterior standing pre- and post-operative photographs. Image courtesy of Alan H. Daniels, MD, and SpineUniverse.com.

Dr. Daniels disclosed the following relationships: Royalties: Springer; Consulting: EOS Imaging, Orthofix, SpineArt, Stryker; Research Support: Orthofix, Southern Spine.

Peer Case Discussion

Dr. Daniels and colleagues present a challenging case of an elderly patient requiring extensive thoracolumbar deformity correction surgery.

Since we do not have the clinical and radiographic data preceding the index operation, I will refrain from labeling it an “unsuccessful” surgery. Nonetheless the current presentation is that of a coronally and sagittally malaligned patient with residual stenosis who requires extensive spinal reconstruction surgery.

The goal is simple: To decompress and realign the spinal column and provide a more harmonious spinopelvic balance. The corrective techniques are anything but that. When the lower lumbar vertebrae are fused, a three-column osteotomy (PSO) is typically required to achieve adequate correction. In this case, multiple posterior column osteotomies (PCOs) with gradual correction were employed to obtain acceptable results.

Of note, though the PI-LL mismatch has improved, the PT remains quite high indicating pelvic retroversion is needed to maintain alignment. The true residual deformity is thus more extensive than the post-operative SVA would indicate.

Lastly, and as the authors note, the patient is at risk for PJK/PJF as both the T1 slope and the C2-C7 SVA remain high placing stress on the UIV and UIV+1.

Overall, Dr. Daniels and colleagues are to be commended for an excellent technical and clinical outcome in this challenging case. It is paramount to understand the global alignment of the spine before focal surgery is undertaken. Not appreciating this can lead to poor outcomes and further deformity.

Authors' Response to Peer Case Discussion

We greatly appreciate Dr. Baaj’s insightful commentary.

We agree this gentleman still has an elevated PT and is “under-corrected” by traditional measures. However, with this frail elderly gentleman a detailed pre-operative discussion was held, and he elected to not undergo 3-column osteotomy due to the operative risk and also higher risk of PJK/PJF with larger correction. Shared decision making is key with these complex deformities in elderly patients.

Community Case Discussion (1 comment)

SpineUniverse invites spine professionals to share their thoughts on this case.

Thank you for sharing this interesting case. It is often challenging to decide what do in geriatric patients with symptoms of stenosis and associated deformity. Since we do not have the images prior to his first surgery, we cannot appreciate the magnitude of initial deformity. We can understand the rationale of the first surgeon to do a more limited decompression for the most stenotic segments given the patient’s age.

Knowing the time between first surgery and new presentation would have been useful to determine the speed of deterioration. Still, given the coronal deformity (64 degree) and imbalance, I can imagine that approaching the problem initially from a deformity perspective would have probably been better.

Two comments that could be useful for readers. I doubt the sagittal imbalance of SVA 359mm is truly “structural”. It probably has a big postural component to it (patient trying to alleviate stenosis symptoms, back muscle pain and weakness). Postural element has to be excluded when deciding on the type of correction and osteotomy needed. This is actually proven in this case by the decent post op alignment despite doing simple Grade II osteotomies rather than a PSO which would have been needed for correction if SVA was truly a fixed structural deformity.
Also noted, The mismatch of 9.1 degrees in PI between preop and post op measurements is confusing and likely due to some measurement error since PI is a fixed parameter that is not expected to change.

Finally, it is helpful to evaluate hip joint mobility in such patients due to its value in compensation. The patient has advanced bilateral Hip arthritis. As Dr. Baaj noted, his PT remains high and he is able to maintain good posture with pelvic retrovesion. However as his arthritis advances further, he may lose that posture and SVA further increases. In such cases hip replacement can also help with good posture and if severely symptomatic, can be done prior to spine correction.

Again, thank you for sharing this interesting case and congratulations on the good results.


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