IN THIS ARTICLE: • Less invasive spine procedures can reduce adverse events and improve clinical outcomes. • Such surgeries take advantage of new imaging technologies and protocols.

Minimally invasive spine surgery aims to reduce trauma to the spine and surrounding tissues during exposure while accomplishing the same goals as an open procedure. Minimally invasive procedures can carry lower risks of adverse events and promote a faster recovery time than standard open back surgery, given the limited soft tissue damage. “We think about minimally invasive spine surgery as a customized treatment program for each patient, which can potentially optimize their clinical outcome, enhance their safety and satisfaction, and carry an economic benefit,” says Thomas D. Cha, MD, MBA, assistant chief of the Orthopaedic Spine Center at Massachusetts General Hospital.

Patients who undergo traditional forms of surgery may return to the clinic or to their physician many months after such surgeries complaining of symptoms unrelated to the original pathology, such as muscle pain, which may result from scar tissue due the trauma of the procedure. The goal of the minimally invasive approach is to induce less damage to the tissues during the surgery so that recovery goes more quickly. It may also reduce the risk of adverse outcomes[1] such as:

 

  • Surgical site infection
  • Severe blood loss
  • Deep vein thrombosis
  • Pulmonary embolism
 

Approaches to minimally invasive procedures are varied. The standard surgical approach to a lumbar spine problem, for instance, involves making an incision, retracting the muscles to get to the spine, opening up the spinal canal, decompressing the nerves, and—if the patient requires stabilization such as a fusion of vertebrae—inserting screws, adding bone graft and then closing up the incision. This can be done from an anterior, posterior, side or lateral approach. Minimally invasive techniques are available for all of these approaches.

The advantage of a minimally invasive approach also makes this a challenging procedure as the surgeon purposefully does not expose as much of the spine and instead uses specialized equipment to access a specific area of the spine through smaller incisions. A specialized retractor is inserted through the skin and soft tissues to the spine, creating a tunnel for the surgeon to access the problem area.

Since the surgeon performing a minimally invasive procedure cannot see the spine directly, they rely on intraoperative navigation systems such as fluoroscopy to identify the patient’s anatomy and confirm the exact location of the pathology. However, basic fluoroscopy requires numerous images during the procedure and therefore can expose the patient and staff to increased dosages of radiation. Some of the more novel fluoroscopic navigation stations work by displaying real-time X-ray images of the patient’s spine on a computer screen, which allows the surgeon to see the 3D anatomy accurately and in real time but does not require additional radiation exposure (see figure 2).

 

Finding the right fit

Preparations differ slightly for minimally invasive surgery than the traditional procedure. Surgeons, physical therapists and nurses should be briefed that these patients will have different types of symptoms, including the pain they experience, and may need different management strategies, according to Dr. Cha. For instance, patients who have undergone a minimally invasive procedure are likely to mobilize very rapidly after surgery and be discharged from the hospital much more quickly than with traditional open procedures. Patients for any type of surgery need to be educated about reasonable expectations and potential risks unique to minimally invasive spine surgery and should optimize their physical condition (e.g., strength and mobility) with exercise and conditioning before and after the procedure.

Objective measures for the relative success of minimally invasive procedures have proven difficult so far. In spine surgery, two patients with similar imaging findings can complain of very different symptoms, which makes it challenging to set up a clinical trial to study them side-by-side. The current methodology uses retrospective data on the safety of minimally invasive surgery, but relatively little data exists to date comparing minimally invasive surgery to open surgery for a specific clinical outcome. Nevertheless, Dr. Cha is optimistic. “Minimally invasive spine surgery has been evolving over the decade and I anticipate we will see more data coming out on the effectiveness and further refine the indications for these procedures over the next five to ten years,” he said.

In the meantime, less invasive procedures should be one of a range of surgical approaches to treat spine problems. “Minimally invasive spine surgery is very often performed at Mass General in both the cervical and lumbar spine procedures; however, certain pathologies may only be amenable to an open approach depending on the anatomical challenges,” said Dr. Cha. “But it is important that the surgeons have all these skills and capabilities to offer in order to customize what is best for each patient.”

[1] Jenis LG, Hsu WK, O'Brien J, Whang PG. “Recent advances in the prevention and management of complications associated with routine lumbar spine surgery.” J Bone Joint Surg Am. 2013 May 15;95(10):944-50.