Grade 2 Spondylolisthesis at L4-5 treated by XLIF

One of the most frequent reasons for spinal surgery is still spondylolisthesis. Patients with degenerative spondylolisthesis are often advised to undergo fusion.

Although the advantages of surgical treatment compared to non-surgical care for this condition have been demonstrated in the long run, it is only in recent high-quality data that the cost-effectiveness of this procedure has been established.

Modern developments in minimally invasive surgical technology are currently being utilized to treat spinal conditions. An approach known as extreme lateral interbody fusion (XLIF) has been proposed as a secure and minimally invasive substitute for conventional open fusion surgeries.

Although XLIF has been suggested for treating spondylolisthesis up to grade 2, the potential risk of neural complications associated with lateral approaches to the spine raises concerns about its safety. The concerns are particularly significant at the L4-5 level because the lumbar plexus is located most ventrally in that region. The risk is further aggravated in the presence of marked anterolisthesis at this level.

On average, patients experience a hospital stay of 1.2 days, and their hemoglobin levels decrease by 1.4 g. Transient pain in the upper thigh and weakness in hip flexion can be expected shortly after surgery due to trauma to the psoas muscle.

Grade II spondylolisthesis is most frequently observed at the L4-5 level, although single level presentations at L2-3 and L3-4 are also identified. Although the composition of biologic materials may differ, the majority of them contain demineralized bone matrices. While transpedicular fixation is the primary method utilized for treating grade II spondylolisthesis, transpedicular facet fixation is also a viable option.

According to literature, dynamic radiographs show no signs of radiographic instability after 12 months, and all patients appear to have bone growth spanning the interbody space. Age, BMI/obesity, preexisting comorbidities, previous surgery, number of levels treated, or unilateral versus bilateral fixation do not appear to affect radiographic improvement, slip reduction, or maintenance of improvements in VAS at the last follow-up.

The patient’s satisfaction and willingness to undergo the procedure again are contingent on the extent of slip improvement. Based on available literature, while the average correction is well-preserved, 6.4% of patients experience a loss of more than 3 mm in listhetic correction and 6.4% experience a loss of more than 3 mm in disk height. Most patients consider themselves either “satisfied” or “very satisfied” with the outcomes of the procedure, and nearly 100% of them express their willingness to undergo the same procedure again.

The literature has reported the application of XLIF in treating degenerative spinal conditions, along with its comparatively lower incidence of complications when compared to traditional open approaches, be it anterior or posterior. The procedure results in a remarkable reduction in listhetic deformity and improvement in disk height, which are sustained over time.

The clinical outcomes show a significant improvement in VAS, which is consistently maintained up to one year. Clinical measurements demonstrate the alleviation of stenotic symptoms due to the indirect decompression and stabilization achieved through the procedure.

Complications

Literature reports indicate an occurrence of groin numbness (without motor deficits) when using an endoscopic transpsoas approach without neurological monitoring. There is a lot of debate around the neurological deficits linked to lateral approaches.

The L4-5 level poses the highest risk for the lumbar plexus in a transpsoas approach, as per the anatomical and radiographic documentation. Furthermore, the plexus is placed at even greater risk with anterolisthesis of the superior vertebral body, as it is pushed even more ventrally, further increasing safety concerns.

Nevertheless, if proper attention is given to the technique details mentioned above, and real-time neurologic monitoring is conducted, successful treatment of grade 2 spondylolisthesis segments, particularly at L4-5, can be achieved without any neurologic damage.

Surgery has been demonstrated in large randomized trials to result in better patient outcomes than nonoperative treatment for spondylolisthesis. Various techniques have been utilized to treat spondylolisthesis, including decompression alone, instrumented PLF, PLIF, ALIF, TLIF, as well as minimally invasive procedures like MIS ALIF or MIS TLIF.

However, there is no clear consensus on which technique is the best. Substantially cost-effective compared to conservative care, instrumented fusion for the treatment of degenerative spondylolisthesis has been demonstrated to be clinically effective. MIS XLIF fusion for spondylolisthesis is associated with significantly fewer complications compared to traditional open approaches, according to the reported literature. Additionally, traditional open spinal fusions have been reported to result in much longer hospital stays.

The use of XLIF has been demonstrated to be a secure and efficient method to manage grade 2 spondylolisthesis specifically at the L4-5 level. This technique leads to significant clinical and radiographic improvement that is sustained over a period of time. Real-time neurologic monitoring and meticulous technique are essential.