A Sideways Look at Spinal Fusion By Christopher Heck, MDSpine Surgeon
While there are seemingly countless spinal surgical approaches and techniques, all spinal surgeries fall into one of two categories: decompression or stabilization. Decompression involves taking pressure off neurologic structures including the spinal cord and, more commonly, nerve roots to improve function and relieve pain. Stabilization involves restoring structure to one or more spinal segments, i.e. two adjacent vertebra and the intervening disc, by creating an environment for bone to grow from one vertebra to the next. This may be performed to treat gross instability from a traumatic fracture or chronic instability from a degenerative spondylolisthesis. The evolution of spinal fusion began with placement of bone graft along the posterior spine. While easy to perform, there are limitations to a successful posterior fusion including decreased surface area for bone growth after a decompressing laminectomy. In addition, this approach results in diminished vascularity and nutrition to the fusion bed from surrounding muscle injury which can inhibit bone formation. Anterior surgical approaches improved graft options, but included risks for different complications such as vascular injury and ileus development in the lumbar spine and lung deflation sequelae from anterior
thoracic approaches. A newer approach to spinal fusion is generically called the “lateral approach” with trademarked names such as XLIF (eXtreme Lateral Interbody Fusion) and DLIF (Direct Lateral Interbody Fusion). First described in the American literature in 2003, this technique involves approaching the spine from the side of the body. The benefits of this technique include providing a large bone graft into the disc space which is where 80 percent of forces are borne by the spine. This allows for more aggressive correction of deformities and restoration of disc height. These mechanical alterations open the spinal canal and neuroforamen resulting in “indirect” decompression, i.e. taking pressure off nerve roots without directly visualizing the nerves through a traditional laminectomy approach. In a 2010 radiographic study, the authors identified a 25 percent increase in neuroforaminal area and a 33 percent increase in spinal canal diameter from indirect decompression alone after lateral spinal fusion surgery. In addition, this surgical approach includes small penetrations of the oblique muscles (external oblique, internal oblique and transverse abdominis) and psoas muscle (which resides along each side of the spine and produces hip flexion). Due to the lack of muscle stripping from the spine which is often required for traditional posterior approaches, there is significantly
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less blood loss, dead space creation, and muscle damage. These factors decrease infection risk and speed up recovery. The typical patient will be discharged the day after surgery rather than three to four days after traditional open posterior fusions. In a 2010 study of 60 octogenarians undergoing either lateral or posterior based fusion surgery, the authors found a blood transfusion rate of 0 percent versus 70 percent, discharge to home rate of 92.5 percent versus 0 percent, and a six-month mortality rate of 2.5 percent versus 20 percent. This minimally invasive approach
has evolved to treat thoracic pathologies such as tumor and discitis/osteomyelitis without the need for lung deflation and chest tube insertion. So, when treatment options include a spinal fusion, don’t turn around and ignore the problem. Just take a look at it from the side, instead. Christopher Heck, MD is a spine surgeon who practices at Southlake Orthopaedics Sports Medicine and Spine Center.
Efficacy of Apple Watch Monitoring Heart Rhythm By Jose Osorio, MD
The Apple Watch and other wearables are now able to monitor your heart rhythm. The Apple watch can detect irregular heart rhythms, and if it does so five times, it will prompt you to record your rhythm. In that way, it can also be used to diagnose atrial fibrillation. Does that mean that if the Apple Watch says I have an irregular rhythm that I have Afib? The simple answer is… not always. If you have atrial fibrillation and your risk of stroke is high, then it’s a good thing to catch it earlier and get further testing. However, as with any screening program, using the apple watch to diagnose afib may have drawbacks. The US Preventive Services Task Force does not recommend ECG screening for healthy adults at low risk of heart disease. The concern is that patients who do not have a condition may be falsely diagnosed by the apple watch as having an irregular heart rhythm, and end up undergoing series of tests to prove they do or do not have it. If the watch says you have afib, what are the chances you do have it? The majority of people wearing an Apple Watch have a very low risk of having atrial fibrillation – most owners are 55 or younger. In that group, the risk of having afib is low. So even if the apple watch is wrong only a small percent of time, physicianscientist Sekar Kathiresan estimates that the alerts by the watch will be wrong 45 percent of the time.
How do you diagnose Afib? Atrial fibrillation is diagnosed with an analysis of your heart rhythm, done with an ECG (electrocardiogram). This can be done in the clinic, using 10 electrodes for a 12-lead EKG or with monitors that you can take home. There are also implant-
able monitors, with batteries that last up to 3 years, that can help in some situations. Rhythm monitors are important tools for doctors to diagnose afib, because many patients have episodes of afib lasting minutes or hours (paroxysmal afib), and when they see a doctor, they may be in normal rhythm. Therefore, using a monitor for a few days or even weeks (or years with implantable monitors) can help in the quick and appropriate diagnosis of afib.
What should I do if my Apple Watch says I have an irregular heart rhythm? You should contact your primary care physician or cardiologist. Many patients will end up needing evaluation by an electrophysiologist, who is a cardiologist specialized in heart rhythm problems. The first step for most will be to use a patch monitor, which can record your heart rhythm continuously for weeks at a time. And it later can be analyzed for signs of afib or other irregular heart rhythms. Some patients will need further testing, such as an echocardiogram or stress testing – but that decision is individualized. Jose Osorio, M.D. is the Medical Director, Atrial Fibrillation Clinic and Cardiac Electrophysiology, Grandview Medical Center.
Birmingham Medical News May 2019