Severe Sagittal Imbalance Correction

History

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.

Examination

• 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).

Figure 1. Standing scoliosis posteroanterior imaging with measurement of lumbar coronal Cobb angle.

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).

Figure 2. Standing scoliosis lateral x-ray: PT, PI, LL, PI-LL mismatch, SVA, and TPA.

Pre-Treatment Clinical Photographs

Lateral (Figure 3) and anterior (Figure 4) standing photographs of the patient.

Figure 3. Lateral photo image of the patient standing.

Figure 4. Anterior photo image of the patient standing.

Diagnosis

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

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.

Figure 5. Intraoperative photograph: note the intralaminar fixation construct fixating the UIV to UIV+1 for softer cranial landing.

Outcome

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

Table 1. Pre-operative versus 9-month post-operative radiographic alignment parameters.

Post-operative PA x-ray includes lumbar coronal Cobb angle measurement (Figure 6).

Figure 6. Post-operative PA x-ray includes lumbar coronal Cobb angle measurement.

Post-operative lateral x-ray at 9 months includes PT, PI, LL, PI-LL, SVA, and TPA (Figure 7).

Figure 7. Post-operative lateral x-ray at 9 months includes PT, PI, LL, PI-LL, and TPA.

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

Figure 8. Pre- and post-operative lateral standing photographs.

Figure 9. Anterior standing pre- and post-operative photographs.

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

Peer Case Discussion

Ali A. Baaj, MD

Associate Professor of Neurological Surgery
Co-Director, Spinal Deformity and Scoliosis Program

Weill Cornell Medical College, Cornell University

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

Alan H. Daniels, MD

Associate Professor of Orthopaedic Surgery

The Warren Alpert Medical School of Brown University

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.