Reducing surgical levels by paraspinal mapping and diffusion tensor imaging techniques in lumbar spinal stenosis

Reducing decompression levels by diffusion tensor imaging and conventional magnetic resonance imaging in degenerative lumbar spinal stenosis

BACKGROUND

The selection of a correct level in lumbar spinal stenosis (LSS) remains a common problem and is critically important to the effectiveness of this surgical treatment. Surgery is invasive, and extended laminectomy may lead to secondary surgical complications. The application of diffuse tensor imagining (DTI) and paraspinal mapping (PM) in addition to conventional magnetic resonance imaging (cMRI) may be helpful in this respect. However, the superiority of cMRI + DTI over cMRI+ (DTI or PM) in reducing decompression has not yet been established.

METHODS

We compared the surgical levels, determined by cMRI + DTI and cMRI+ (DTI or PM) (self-control). Treatment outcome measurements were performed at two weeks, three months, six months, and twelve months postoperatively.

RESULTS

The surgical levels determined by cMRI ± DTI showed less than that determined by cMRI± (DTI or PM) with statistically significant differences (p value = 0.0199) and cMRI ± PM with no statistically significant differences (p value = 0.5503).

CONCLUSIONS

The effectiveness of cMRI ± DTI in the reduction of the surgical levels in degenerative lumbar spinal stenosis is superior than that of cMRI± (DTI or PM).

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Value of diffusion tensor imaging and tractography in unilateral lumbar disc prolapse

Background

Conventional MR imaging is not enough for evaluation of symptomatic foraminal stenosis, because there is high incidence of false-positive results in asymptomatic elderly patients. Conventional MR cannot quantitatively assess the severity of the nerve lesion. DTI is a non-invasive way to effectively trace the nerve fiber bundle and quantitatively evaluate the nerve injury. DTI with fiber tracking may describe abnormalities beyond the resolution of conventional MR techniques. The aim of this work was to compare between the mean values of diffusion parameters such as fractional anisotropy and apparent diffusion coefficient of the compressed lumbar spinal nerve roots and of the contralateral normal nerve roots. Correlate these parameters with the severity of neurological symptoms. This is a prospective study that was conducted on 50 patients with symptomatic unilateral posterolateral lumbar disc prolapse at a university hospital. They were investigated with diffusion tensor imaging with tractography on a 1.5-T MR. The changes in the mean fractional anisotropy and apparent diffusion coefficient values of the compressed nerves and the relationship between these changes and the severity of the neurological side effects using Japanese Orthopedic Association score and visual analogue scale were investigated.

Results

The mean fractional anisotropy values were significantly lower (p ≤ 0.001), and mean apparent diffusion coefficient values were significantly higher (p ≤ 0.001) in compressed nerves than in contralateral intact nerves. There were strong correlations between the DTI parameters and the severity of the neurological symptoms as assessed using the Japanese Orthopedic Association score and the visual analogue scale.

Conclusion

In patients with lumbar disc prolapse, radicular diffusion parameters are affected in the compressed roots in comparison to the healthy roots and this affection is correlated with the degree of prolapse and with the severity of neurological symptoms. DTI with fiber tracking provide clinically relevant information and describe abnormalities beyond the resolution of conventional MR techniques.

Utility of diffusion tensor imaging for guiding the treatment of lumbar disc herniation by percutaneous transforaminal endoscopic discectomy

The purpose of this study was to evaluate the utility of diffusion tensor imaging (DTI) for guiding the treatment of lumbar disc herniation (LDH) by percutaneous transforaminal endoscopic discectomy (PTED). We collected the clinical data of a total of 19 patients: 10 with unilateral S1 nerve root injury, 6 with unilateral L5 nerve root injury, and 3 with unilateral L5 and S1 nerve root injury. All patients underwent DTI before surgery, 3 days post-surgery, 30 days post-surgery, and 90 days post-surgery. The comparison of the fractional anisotropy (FA) values of compressed lateral nerve roots before surgery and 3, 30, and 90 days post-surgery demonstrated the recovery of nerve roots to be a dynamic process. A significant difference was found in the FA values between compressed lateral nerve roots preoperatively and normal lateral nerve roots before surgery, 3 days post-surgery and 30 days post-surgery (p < 0.05). There was no significant difference in FA values between compressed lateral nerve roots and normal ones 90 days post-surgery (p > 0.05). DTI can be used for the accurate diagnosis of LDH, as well as for postoperative evaluation and prognosis, and it is thus useful for the selection of surgical timing.

Relationship between the benefits of paraspinal mapping and diffusion tensor imaging and the increase of decompression levels determined by conventional magnetic resonance imaging in degenerative lumbar spinal stenosis

BACKGROUND

In lumbar spinal stenosis (LSS), at most times, several levels are impaired and selecting the correct level remains a common problem for surgeons, as surgery remains invasive, and extended laminectomy may lead to secondary surgical complications. Therefore, helping to select the correct level may be useful for surgeons. The use of diffuse tensor imaging (DTI) and paraspinal mapping (PM) in addition to conventional magnetic resonance imaging (MRI) may be helpful (Chen et al., J Orthop Surg Res 11:47, 2016). However, with decompression levels determined by conventional magnetic resonance imaging (MRI) increasing, whether the benefits of reducing decompression level of conventional MRI + (DTI or PM) will be more obvious is unknown.

METHODS

Reduced surgical levels that were different between levels determined by conventional MRI + (DTI or PM) and conventional MRI + neurogenic examination (NE) between groups were compared. Treatment outcome measures were performed at 2 weeks, 3 months, 6 months, and 12 months postoperatively.

RESULTS

The reduced levels of three groups showed no statistically significant differences between each other except for two levels and four levels (two levels/three levels, p = 0.085; two levels/four levels, p = 0.039; three levels/ four levels, p = 0.506, respectively).

CONCLUSIONS

With surgical levels determined by conventional MRI increasing, the benefits of DTI and PM will be uncertainly more obvious.

Recent advances in magnetic resonance neuroimaging of lumbar nerve to clinical applications: A review of clinical studies utilizing Diffusion Tensor Imaging and Diffusion-weighted magnetic resonance neurography

Much progress has been made in neuroimaging with Magnetic Resonance neurography and Diffusion Tensor Imaging (DTI) owing to higher magnetic fields and improvements in pulse sequence technology. Reports on lumbar nerve DTI have also increased considerably. Many studies have shown that the use of DTI in lumbar nerve lesions, such as lumbar foraminal stenosis and lumbar disc herniation, makes it possible to capture images of interruptions of tractography at stenotic sties, enabling the diagnosis of stenosis. DTI can also reveal significant decreases in fractional anisotropy (FA) with significant increases in apparent diffusion coefficient (ADC) values in compression lesions. FA values have higher accuracy than ADC values. Furthermore, strong correlations exist between FA values and indications of neurological severity, including the Japanese Orthopedic Association (JOA) score, the Oswestry Disability Index (ODI), and the Roland-Morris Disability Questionnaire (RDQ) in patients with lumbar disc herniation-induced radiculopathy. Most lumbar DTI has become 3T; 3T MRI has made it possible to take high-resolution DTI measurements in a short period of time. However, increased motion artifacts in the magnetic susceptibility effect lead to signal irregularities and image distortion. In the future, high-resolution DTI with reduced field-of-view may become useful in clinical applications, since visualization of nerve lesions and quantification of DTI parameters could allow more accurate diagnoses of lumbar nerve dysfunctions. Future translational studies will be necessary to successfully bring MR neuroimaging of lumbar nerve into clinical use.

Accuracy of magnetic resonance imaging in detecting lumbo-sacral nerve root compromise: a systematic literature review

Background

MRI is considered to be the diagnostic tool of choice in diagnosing nerve root compromise among patients presenting with clinical suspicion of lumbo-sacral radiculopathy. There exists controversy among researchers and clinicians regarding the diagnostic utility and accuracy of MRI in detecting nerve root compromise and radiculopathy. This review evaluated 4 primary diagnostic accuracy studies that specifically assessed the accuracy of MRI in detecting nerve root compromise, as established in the current literature.

Methods

Eight electronic data bases were searched for relevant articles from inception until January 2014. All primary diagnostic studies which investigated the accuracy of MRI in diagnosing nerve root compromise among patients with low back and referred leg symptoms were screened for inclusion. Qualifying studies were retrieved and independently assessed for methodological quality using the ‘Quality Assessment of Diagnostic tests Accuracy Studies’ criteria.

Results

Four studies qualified for inclusion in this review. The sensitivity of MRI in detecting lumbar nerve root compromise was very low at 0.25 (95 % CI) while the specificity was relatively high at 0.92 (95 % CI).

Conclusions

There is lack of sufficient high quality scientific evidence in support or against the use of MRI in diagnosing nerve root compression and radiculopathy. Therefore, clinicians should always correlate the findings of MRI with the patients’ medical history and clinical presentation in clinical decision making.