Direct lateral interbody fusion (DLIF) at the lumbosacral junction L5-S1

New Ultrasound-Guided Approach to Access to the Posterolateral Part of Intervertebral Lumbar Discs: A Cadaveric Study

Background: Approximately 40% of chronic low back pain patients have a discogenic origin. In relation to intervertebral disc injuries, most of them are in the posterior and lateral zone of the disc, involving the anterior lumbar roots and the spinal cord. Objective: The objective was to analyze and describe the accuracy and safety of a new ultrasound-guided approach to target the posterolateral part of the intervertebral lumbar discs in cadaveric specimens. Methods: A cross-anatomical study on sixty cadaver intervertebral lumbar discs was performed. A needle was introduced in the posterolateral part of the discs using ultrasound guidance. A transducer was placed in the anterior abdomen to visualize the discs in cross-section as well. A dissection of the specimen was performed to visualize the final position of the needle tip and its distance from the main lumbar structures. The angulation, length, and distance of the needle from the vertebral spine, the relevant ultrasound anatomical references, and the accuracy of the procedure were evaluated. Results: The needle tip reached the posterolateral part of the discs in 93.3% of the attempts. The mean length of the needle inserted was 79 ± 15 mm, the angulation 129 ± 20.2°, the distance from the spinous process was 77 ± 19 mm, and the distance of the needle to the nerve roots was 2.0 ± 1.2 mm. No statistically significant differences between genders were found. Conclusions: An ultrasound-guided technique can be an accurate and safe technique to perform invasive procedures on the posterolateral part of the intervertebral lumbar discs.

Accuracy of Ultrasound-Guided Needle Placement on the L5 Lumbar Nerve Root: A Cadaveric Study

OBJECTIVES

The aims of the study are to analyze and describe the accuracy of an ultrasound-guided approach to target the L5 root in cadaveric specimens and evaluate whether gender differences exist.

DESIGN

A cross-anatomical study on 40 cadaver L5 nerve roots was performed. A needle was introduced until contacting the L5 nerve root using ultrasound guidance. After that, specimens were frozen and studied by a cross-anatomical view to see the needle's path. The angulation, length, distance from the vertebral spine, the relevant ultrasound anatomical references, and the accuracy of the procedure were evaluated.

RESULTS

The needle tip reached the L5 root at a 72.5% rate. The mean angulation degrees of the needle relative to the skin surface were 75.53 ± 10.17 degrees, the length of the needle inserted was 5.83 ± 0.82 cm, and the distance from the vertebral spine to the point of entry of the needle was 5.39 ± 1.44 cm.

CONCLUSIONS

An ultrasound-guided technique can potentially be an accurate technique to perform invasive procedures on the L5 root. There were statistically significant differences between males and females in the length of the needle introduced. If the L5 root is not clearly visualized, ultrasound will not be the technique of choice.

The phenotypic morphology of human lumbar plexus roots associated with changes in the thoracolumbar vertebral count and trade-off

This study investigated the developmental basis for the human phenotypic morphology of the interaction between the vertebrae and the nerve plexus by evaluating changes in the human lumbar plexus according to various thoracolumbar formulas. The dissection found that the changes in lumbar nerve roots reported by experimental embryology studies to be concomitant with thoracolumbar trade-off, i.e., a change in vertebrae from thoracic to lumbar with no change in the overall thoracolumbar count, were not apparent in humans with the usual 17 or mutant 16 thoracolumbar vertebrae. When vertebral changes in two segments were examined by comparing spines with a reduced thoracolumbar count of 16 to those with an increased count of 18, this tended to show only a single-segment caudal shift of the lumbar plexus. We cannot provide evidence for the phylogenetic difference in the concomitant changes of lumbar nerves and vertebrae, but comparisons between experimental rodents and humans highlighted fewer and shorter lumbar vertebra and more complicated lumbar plexus in humans. Therefore, these multiple differences may contribute to a human phenotypic morphology that is not evident in the concomitant transformation of vertebrae and lumbar nerves reported in experimental rodents.

A Narrative Review of Lumbar Fusion Surgery With Relevance to Chiropractic Practice

OBJECTIVE

The purpose of this narrative review was to describe the most common spinal fusion surgical procedures, address the clinical indications for lumbar fusion in degeneration cases, identify potential complications, and discuss their relevance to chiropractic management of patients after surgical fusion.

METHODS

The PubMed database was searched from the beginning of the record through March 31, 2015, for English language articles related to lumbar fusion or arthrodesis or both and their incidence, procedures, complications, and postoperative chiropractic cases. Articles were retrieved and evaluated for relevance. The bibliographies of selected articles were also reviewed.

RESULTS

The most typical lumbar fusion procedures are posterior lumbar interbody fusion, anterior lumbar interbody fusion, transforaminal interbody fusion, and lateral lumbar interbody fusion. Fair level evidence supports lumbar fusion procedures for degenerative spondylolisthesis with instability and for intractable low back pain that has failed conservative care. Complications and development of chronic pain after surgery is common, and these patients frequently present to chiropractic physicians. Several reports describe the potential benefit of chiropractic management with spinal manipulation, flexion-distraction manipulation, and manipulation under anesthesia for postfusion low back pain. There are no published experimental studies related specifically to chiropractic care of postfusion low back pain.

CONCLUSIONS

This article describes the indications for fusion, common surgical practice, potential complications, and relevant published chiropractic literature. This review includes 10 cases that showed positive benefits from chiropractic manipulation, flexion-distraction, and/or manipulation under anesthesia for postfusion lumbar pain. Chiropractic care may have a role in helping patients in pain who have undergone lumbar fusion surgery.

Surgical treatments for degenerative lumbar scoliosis: a meta analysis

PURPOSE

Degenerative lumbar scoliosis (DLS) is a spinal deformity that typically develops in adults over 50 years old. Although its etiology is unclear, asymmetric degeneration of the spine is the main cause. Individuals with DLS may experience no symptoms of the deformity, mild symptoms, or severe disability. Most patients with DLS receive conservative treatment, while a small number of patients receive surgery for severe DLS with back pain and/or progressive neurological symptoms. A variety of surgical procedures have emerged. However, a systemic comparison of these surgical procedures is currently unavailable. This study reviews the main outcomes and complications of surgical treatments.

METHODS

A meta analysis of main outcomes and complications of surgical treatments of DLS was conducted through searching PubMed and EMbase databases.

RESULTS

A total of 45 studies were included in this study, which were classified into four surgical categories. Nine studies utilized isolated decompression, 12 used short interbody fusion, 17 used long interbody fusion, and 11 studies included patients using short or long interbody fusion or surgery other than fusion, respectively. Decompression surgery is used to release the symptoms of neurogenic claudication. Spine fusion is widely utilized to prevent worsening of the curve. Instrumentation has been used together with fusion to straighten the spine, correct sagittal imbalance, and repair rotational defects. Decompression is commonly combined with fusion surgery when treating an individual with DLS.

CONCLUSION

Despite a high rate of complications, this review demonstrates that surgery is an effective and reasonable treatment intervention for severe DLS and ultimately improves spine function and deformity. This review also suggests that large scale, high quality studies with long term follow-up are needed to provide more reliable evidence for future evaluation.

Comparison of the different surgical approaches for lumbar interbody fusion

This review will outline the history of spinal fusion. It will compare the different approaches currently in use for interbody fusion. A comparison of the techniques, including minimally invasive surgery and graft options will be included. Lumbar interbody fusion is a commonly performed surgical procedure for a variety of spinal disorders, especially degenerative disease. Currently this procedure is performed using anterior, lateral, transforaminal and posterior approaches. Minimally invasive techniques have been increasing in popularity in recent years. A posterior approach is frequently used and has good fusion rates and low complication rates but is limited by the thecal and nerve root retraction. The transforaminal interbody fusion avoids some of these complications and is therefore preferable in some situations, especially revision surgery. An anterior approach avoids the spinal cord and cauda equina all together, but has issues with visceral exposure complications. Lateral lumbar interbody fusion has a risk of lumbar plexus injury with dissection through the psoas muscle. Studies show less intraoperative blood loss for minimally invasive techniques, but there is no long-term data. Iliac crest is the gold standard for bone graft, although adjuncts such as bone morphogenetic proteins are being used more frequently, despite their controversial history. More high-level studies are needed to make generalisations regarding the outcomes of one technique compared with another.

Evidence-based support for S1 transpedicular screw entry point modification

BACKGROUND

In the literature, 'below and lateral to the superior S1 facet' is defined as the basic technique for screw introduction. Until a recently published modification, no analysis for alternative starting point has been proposed nor evaluated, although some surgeons claim to use some modifications. In this study, we analyse the data from anatomical and radiological studies for optimal starting point in transpedicular S1 screw placement.

METHODS

A Medline search for key word combination: sacrum, anatomy, pedicle, screws and bone density resulted in 26 publications relevant to the topic. After a review of literature, two articles were chosen, as those including the appropriate set of data. The data retrieved from the articles is used for the analysis. The spatial relation of S1 facet, pedicles and vertebral body with cortical thickness and bone density in normal, osteopenic and osteoporotic sacrum is analysed.

RESULTS

Presented data advocates for more medial placement of the screws due to higher bone density and lower bone loss in osteoporosis. Medial shift of the starting point does not increase the risk of spinal canal perforation. Osteoarthritic changes within the facet can augment the posterior supporting point for screw. The facet angular orientation is similar to convergent screw trajectory.

CONCLUSIONS

Modified technique for S1 screw placement takes advantage of latest anatomical and clinical data. In our opinion, technique modification improves the reproducibility and may increase stability and the screws within the posterior cortex of the S1 vertebra. Further biomechanical and clinical study should be performed to prove its superiority to classical technique.