Tag Archive | Anterior Approach

Surgical Approach for Cervical Myelopathy: Front or Back?

Propensity Match for OBuzz.jpegSpine surgeons have two basic approach options when performing surgery on patients with degenerative cervical myelopathy—anterior or posterior. Each approach has advantages and disadvantages, and numerous studies have attempted to elucidate which approach might be better for specific clinical situations.

In the June 21, 2017 edition of The Journal of Bone & Joint Surgery, Kato et al. add to the evidence base regarding this question. They report on results from an analysis comparing the two approaches in 80 pairs of “propensity-matched” patients who had multilevel compression myelopathy. Propensity matching allowed the authors to adjust for multiple baseline factors and MRI characteristics, thus minimizing the risk of selection bias.

After the propensity-matched analysis, there were no two-year between-group differences in mJOA score, Neck Disability Index, or SF-36 Physical Component score. The overall rates of perioperative complications were similar between the two groups, although dysphagia and dysphonia were reported only in the anterior group, while surgical site infection and C5 radiculopathy were reported only in the posterior group.

The authors claim that propensity matching helps to “reflect the ‘real-world’ clinical setting and likely has greater generalizability than a smaller, narrowly randomized controlled trial,” but they ultimately conclude that the surgical approach in such cases “should be carefully chosen by evaluating risk profiles in a shared decision-making process on a case-by-case basis.”

More Comparative Data on Surgical Approaches to THA

Implant Survival and THA Approach.jpegThe May 17, 2017 edition of The Journal of Bone & Joint Surgery features a registry-based study by Mjaaland et al. comparing implant-survival/revision outcomes in total hip arthroplasty (THA) among four different surgical approaches:

  • Minimally Invasive (MI) Anterior (n=2017)
  • MI Anterolateral (n=2087)
  • Conventional Posterior (n=5961)
  • Conventional Direct Lateral (n=11,795)

Although the authors analyzed a whopping 21,860 THAs from 2008 to 2013, the findings are limited by the fact that all of those procedures used an uncemented stem.

Overall, the revision rates and risk of revision with the MI approaches were similar to those of the conventional approaches. There was a higher risk of revision due to infection in THAs that used the direct lateral approach than in THAs using the other three approaches. “To our knowledge,” the authors write, “this finding has not been previously described in the literature, and we do not have an explanation for it.” The authors also found a reduced risk of revision due to dislocation in THAs that used the MI anterior, MI anterolateral, and direct lateral approaches, relative to those using the posterior approach.

While the authors found all-cause risk of revision to be similar among all four approaches, they note that the follow-up in the study was relatively short (mean of 4.3 years) and that “additional studies are needed to determine whether there are long-term differences in implant survival.”

JBJS Editor’s Choice—Prevent Nerve Damage During Anterior Hip Approaches

LFCN_Branches.pngWhile anatomy is the foundation of all surgical practice, we at The Journal do not often publish an-
atomic manuscripts. We make exceptions when papers have the potential to influence the practice of orthopaedic surgery in a major way. Such an exception is the cadaver study by Rudin et al. in the April 6, 2016 JBJS.

The authors focus on the course of the lateral femoral cutaneous nerve (LFCN) of the thigh. This is a highly relevant anatomic structure because of the increasing interest in the anterior approach for hip arthroplasty, for anterior approaches to the hip for open reduction of femoral-head or proximal-femur fractures, and even for surgically treating femoroacetabular impingement.

The major take-home point is the extensive variability of this nerve in terms of where it exits the pelvis and its three different branching patterns from there (see illustration). These anatomic findings should alert the operating surgeon to make skin incisions as lateral as possible and to take extra caution when creating the interval deep to the fascial plane.

Rudin et al. have performed a service to the orthopaedic community by carefully defining the high degree of variability in the course of this nerve, which often is in harm’s way during common surgical exposures. Although injury to the sensory-only LFCN will not lead to major neurological complications, the authors conclude that patients undergoing anterior hip approaches should be informed of the risks of sensory loss or dysesthesia.

Marc Swiontkowski, MD

JBJS Editor-in-Chief

JBJS Classics: Cervical Discectomy and Interbody Fusion

JBJS-Classics-logoEach month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.

It is rare that an article published more than 50 years ago continues to have an impact on clinical practice today. But that is the case with “The Treatment of Certain Cervical-Spine Disorders by Anterior Removal of the Intervertebral Disc and Interbody Fusion.” What make this article so unique are the details that Drs. George Smith and Robert Robinson put into describing the procedure and the careful follow-up of their early experience with this technique.

I have had a copy of this article in my files since I was a resident at Yale, training with Wayne Southwick, who had trained with Dr. Robinson at the time this approach to the cervical spine was developed. The two key contributors to anterior cervical spine surgery back in the 1950s were Dr. Robinson and the neurosurgeon Dr. Ralph Cloward.

Dr. Robinson’s technique has the support of biomechanical principles, which makes this particular approach and bone-graft fusion construct inherently stable; hence, its continued use to this very day. However, back in the ‘50s, and even when I trained in the 1970s, hardware to stabilize the spine following discectomy was not available in the US.

The approach that these authors described is very versatile and is utilized for all sorts of anterior procedures, including removal of intervertebral discs, arthrodesis, and vertebrectomy, and it allows for doing multiple-level procedures. The technique I use today is the same one that Dr. Southwick taught me and that he learned directly from Dr. Robinson.

Dr. Robinson has had a major impact on cervical spine surgery, and it was estimated that at one time 33% to 50% of members of the Cervical Spine Research Society were trained by him, by one of his residents or fellows, or by one of their residents or fellows—Dr. Robinson’s “offspring.”

I believe this technique will continue to stand the test of time, as it has during the past half century, and will have a major influence on spine surgery well into the future.

Charles Clark, MD

JBJS Deputy Editor for Adult Reconstruction and Spine