Six spine surgeons weigh in on the most important innovations in spinal deformity procedures over the last decade.
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Question: What are the biggest innovations in spinal deformity care in the last 5 to 10 years?
Gerardo Zavala II, MD. Director of Spine Surgery at St. Luke's Baptist Hospital (San Antonio): Patient selection and outcomes. In both MIS and open deformity cases, there has been a bigger understanding of which patients will do well and which will need some help because of their comorbidities, diabetes, smoking and heart disease. I also feel spine surgeons, in general, are incorporating better spinal mechanics in their cases. Surgeons are thinking about resorting sagittal balances and sacral slopes during their cases.
Rajesh G. Arakal, MD. Spine Surgeon at Texas Back Institute (Plano): Better X-ray imaging, such as EOS and better longitudinal imaging and software, which allows for quicker marking of preoperative imaging for parameters for correction and understanding better what our goals are. Also, better intraoperative imaging such as intraoperative CT and robotic navigation or other software-based navigation [are important innovations].
Jeremy Smith, MD. Orthopedic Spine Surgeon at Hoag Orthopedic Institute (Irvine, Calif.): 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 patient's 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, determining the necessary sagittal plane correction to reproduce sound biomechanics and an optimal surgical outcome has become very objective. Adhering to these principles has significantly improved radiographic and clinical outcomes while still utilizing traditional diagnostic radiographs.
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 and pelvic position are important variables that may indirectly influence spinal balance. Pathologies that influence these compensatory variables also have to be addressed — flexion contractures, hip/knee degenerative joint disease, etc. Traditional radiographs essentially ignore these factors and without a keen clinical diagnostic sense these influences are often unaccounted 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 utilizing less radiation than a standard X-ray. 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 contributing. The system is slowly being introduced in major spinal surgery centers and has become integral in the surgical planning process.
In order to correct a deformity, it is critical that the surgeon recognize the character of a curve and all other musculoskeletal influences. 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 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. Perioperative complications are commonplace and are often expected, ranging from acute blood loss to catastrophic neurologic compromise. They often lead to an 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 and allows 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.
Payam Farjoodi, MD. Orthopedic Spine Surgeon at Spine Health Center at MemorialCare Orange Coast Medical Center (Fountain Valley, Calif.): The acknowledgement and understanding of pelvic parameters and global balance in spine surgery is the biggest innovation in spinal deformity care in my opinion.
Isador H Lieberman, MD. Spine Surgeon at Texas Back Institute (Plano): Firstly, the full appreciation of Dr. Jean Dubousset's philosophy of balancing the spine, AKA "the cone of economy." Secondly, the advances in robotics that make the surgeon more precise and more efficient, and thirdly, the recognition and treatment of osteoporosis.
Brian R. Gantwerker, MD. Founder of the Craniospinal Center of Los Angeles: I would have to say by far, spinal robotics. The new systems coming out are going to simply break open the possibilities. Coupled with advanced intraoperative imaging and minimal access surgery, these are driving the market and practice of deformity correction.