Editorial: Axial interbody fusion

Abstract

Axial lumbar interbody fusion (AxiaLIF) is a procedure developed to use the presacral space to achieve interbody fusion between L-4 and S-1. The procedure offers an alternative to anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF) to achieve interbody fusion. Lindley et al.1 report their results in 68 patients who underwent AxiaLIF surgery at 2 institutions between October 2005 and June 2009. The authors performed a retrospective review of this patient population to evaluate complications from AxiaLIF. All patients underwent pedicle screw fixation in addition to AxiaLIF. Most of these patients had bone morphogenetic protein placed within the implant. The reported fusion rate was more than 91%. Sixteen patients had 18 complications (26.5%). The complications reported by the authors included pseudarthrosis (8.8%), superficial infection (5.9%), sacral fracture (2.9%), rectal injury (2.9%), pelvic hematoma (2.9%), wound leakage (1.5%), and temporary S-1 radiculopathy (1.5%). Infections in 2 patients were managed with empiric antibiotics, and the other 2 patients required surgical drainage and irrigation. There was an additional patient who developed drainage from the skin incision, but reportedly did not appear to have signs of infection. The 2 pelvic hematomas that occurred are a matter of concern. In the first case the patient became tachycardic postoperatively and required the transfusion of 7 U of packed red blood cells. The second patient developed pain on postoperative Day 3, and a CT scan demonstrated a large pelvic hematoma. This patient was treated conservatively and observed, and it appears that the hematoma was absorbed by 4 months postoperatively. These complications are important to note because, as the authors point out, some centers perform this surgery as an outpatient procedure. The 2 patients with rectal injuries in this series required a diverting ileostomy and/or colostomy as part of the surgical repair of the injury. The authors suggest that adhesions from prior abdominal procedures may place a patient at increased risk for a rectal injury during the AxiaLIF. Therefore, surgeons should ask patients if they have a history of colorectal area adhesions from prior surgery or other causes. Furthermore, some patients have an abnormally curved sacrum, which may allow the rectum to fold into the grooves of the sacrum. The preoperative imaging should be reviewed to look for such abnormalities. It is likely that rectal injuries may be avoided in this procedure if the patient’s history and anatomy are taken into account. Alternate methods exist for interbody fusion of L4– S1. Each procedure, whether it be ALIF, PLIF, TLIF, or AxiaLIF, has advantages and disadvantages. The extent of direct and indirect decompression as well as the extent of fusion differs between the various techniques and should be determined on a case-by-case basis.2 In addition, there are complications that are unique to each procedure, and patients should be counseled thoroughly regarding those risks. The authors should be congratulated on providing valuable information on the complications associated with AxiaLIF. These complications and the strategies for avoiding them are important matters to consider for spine surgeons contemplating performing an AxiaLIF.