Dr. Jeremy Smith, Orthopadic Spine Surgeon with Hoag Orthopedic Institute was recently
asked to participate in a
Becker's Spine Review online article which asked six spine surgeons from across the United States
about what the most clinically relevant
spinal deformity care innovations have taken place over the past 10 years.
Here is Dr. Jeremy Smith's response:
Over the past decade advances in the treatment of spinal deformity have
allowed surgeons to address more complex sagittal and coronal curvatures
more accurately, safely, and reproducibly. Although the underlying goal
of surgery (deformity correction and arthrodesis) remain the same, some
pivotal changes in the diagnostic workup, preoperative preparation and
surgical technique have improved outcomes and overall made deformity surgery
far less dire.
Traditionally the focus on
scoliosis correction has been based on improving deformities in the coronal plane.
A surgical correction did not take into account sagittal plane deformities
as coronal curvatures display a more profound clinical presentation (rib
hump, pelvic or shoulder obliquity). More recent data support the importance
of the sagittal plane as being a greater influence on morbidity, outcome
and disability. Addressing a global sagittal alignment has proven more
effective in improving all outcomes associated with surgery. Furthermore,
the definition of a patients intended sagittal parameters (lumbar lordosis,
thoracic kyphosis and sagittal vertical axis) has been well defined as it relates to pelvic
alignment. The pelvic incidence, a static parameter that does not change
during a lifetime, determines the necessary lumbar lordosis needed to
maintain global sagittal alignment. With these parameter definitions in
place, defining the necessary sagittal plane correction to reproduce sound
biomechanics and an optimal surgical outcomes has become very objective.
Adhering to these principles have significantly improved radiographic
and clinical outcomes and diagnostically utilize traditional radiographic imaging
In line with maintaining global sagittal alignment principles, it is important
to take the entire musculoskeletal system into account when addressing
compensatory measures that allow a patient to remain clinically balanced.
Hip and knee flexion is an important variable that may indirectly influence
balance. Pathologies that influence these compensatory variables also
have to be addressed (flexion contractures, hip/knee degenerative joint
disease). Traditional radiographs essentially ignore these factors and
without a keen clinical diagnostic sense these influences are often not
accounted for. Fortunately, imaging systems that are looking at the entire
patient in a standing position make these influences difficult to ignore.
The EOS imaging system enables the surgeon to account for all of these
parameters by imaging the entire body in an upright position. The system
visualizes the patient in a true physiologic upright standing position
and gives a clear sense of balance and the multiple variables that are
In order to correct a deformity it is critical that the surgeon recognize
it and all influences within the musculoskeletal system. This includes
understanding how much correction is necessary. The aforementioned diagnostic
breakthroughs have allowed the surgeon to do this with significant accuracy.
The traditional methods of correction, particularly in the sagittal plane,
often involve rather invasive surgical techniques that are inaccurate,
morbid and technically difficult. The osteotomy is the cornerstone of
correction and involves removing posterior bone and often shortening the
spinal column. These surgeries are considered the most technically challenging
and are often performed by surgeons trained specifically in spinal deformity.
Complications are commonplace and often expected in these procedures ranging
from acute blood loss to catastrophic neurologic compromise. They often
lead to extended hospital stay and a lengthy recovery. Along with the
pelvic parameter influence and global sagittal alignment principles came
the reintroduction of anterior segmental correction using interbody grafting
techniques. The so-called anterior column realignment surgery involves
standard anterior discectomy techniques that allow for powerful segmental
lordosis correction. Angled grafts ranging from 15 to 30 degrees can achieve
a correction similar to that of an osteotomy with far less morbidity,
blood loss, hospital stay and recovery. Having this technique and applying
sagittal alignment principles allows a surgeon to treat nearly every spinal
reconstruction surgery as a deformity thus removing some of the iatrogenic
flatback deformities from being a prominent issue.