Current Management of Cervical Spondylotic Myelopathy

Sensorimotor network ALFF markers as prognostic indicators of cervical spondylotic myelopathy post-decompression surgery outcomes

PURPOSE

To investigate the prognostic value of amplitude of low-frequency fluctuations (ALFF) within the sensorimotor network (SMN) in patients with cervical spondylotic myelopathy (CSM) following decompression surgery.

METHODS

Eighty-three presurgical CSM patients (pre-CSM), 60 of the same group followed-up 3 months after decompression surgery (post-CSM) and 83 healthy controls (HC) matched for age, sex and level of education underwent resting-state functional magnetic resonance imaging scans by 3.0 T MR. Then, ALFF values measurements were compared and ALFF alterations were assessed among pre- or postsurgical CSM patients and HC, as well as correlations with clinical indexes by Pearson correlation.

RESULTS

Compared with HC, the ALFF value of left inferior parietal marginal angular gyrus was decreased and the bilateral medial frontal gyrus was increased within pre-CSM (GRF correction). Compared with HC, the ALFF values of the left precentral gyrus, superior marginal gyrus, inferior parietal marginal angular gyrus, parietal lobule and postcentral gyrus decreased, while the ALFF value of the left auxiliary motor area, right anterior cuneiform lobule and right parietal lobule increased within post-CSM. Compared with pre-CSM patients, post-CSM patients had lower ALFF value in bilateral precuneus and precentral gyrus, but increased ALFF value in left medial superior frontal gyrus (Frontal_Sup_Medial_L). The ALFF value of the bilateral precuneus was positively correlated with the mJOA improvement rate, and the ALFF value of Frontal_Sup_Medial_L was positively correlated with the upper and lower limb scores within post-CSM.

CONCLUSION

Functional impairment and plasticity of SMN exist in CSM patients before and after surgery. ALFF within the SMN serves as a potential biomarker for predicting recovery outcomes.

CT myelography by intrathecal injection of contrast medium though percutaneous administration route visualizes compressed cervical spinal cord in a mouse

BACKGROUND

Chronic compressive myelopathy (CCM) is a major cause of spinal cord disorders in the elderly, in which the spinal cord is compressed by bony or soft tissue structures. Although computed tomography myelography (CTM) has been clinically used for the diagnosis of CCM, a method of CTM in rodents remains to be developed.

NEW METHOD

A 50 μl Hamilton syringe attached to a disposable needle was percutaneously inserted into the subarachnoid space (cisterna magna) between the occipital bone and C1 lamina in an anesthetized adult mouse, followed by the injection of contrast medium and CT imaging.

RESULTS

CTM clearly visualized the shape of the spinal cord of intact mice and tiptoe-walking Yoshimura (Twy) mice without any health issues.

COMPARISON WITH EXISTING METHOD(S)

Unlike histology, the current method functions in live mice, directly depicts the compressed spinal cord, and provides clinically related image information. Furthermore, the intrathecal administration of contrast medium through the percutaneous route makes CTM less invasive and takes less time than a conventional intrathecal injection method.

CONCLUSIONS

The CTM method used in the present study enables clear visualization of the shape of the dural sac and spinal cord and is useful when conducting experiments on CCM and other spinal diseases in rodents.

The "pancake-like" enhancement in cervical spondylotic myelopathy

Cervical spondylotic myelopathy, characterized by chronic spinal cord compression resulting from degenerative spine changes, manifests with a spectrum of neurological and pain symptoms. Despite the complexity of intramedullary spinal cord abnormalities, employing a systematic approach to differential diagnosis, considering factors such as lesion location, cord length, segment involvement, and enhancement pattern, can significantly aid in narrowing down the potential diagnoses, potentially avoiding invasive diagnostic procedures and guiding treatment decisions. This article presents two cases of cervical spondylotic myelopathy characterized by progressive weakness and paraesthesia, exhibiting progressive bilateral upper extremity numbness, tingling, and impaired gait, with cervical myelopathy evident on MRI displaying transverse pancake-like gadolinium enhancement.

Muscle synergy and kinematic synergy analyses during sit-to-stand motions in hallux valgus patients before and after treatment with Kinesio taping

OBJECTIVES

To explore the impact of hallux valgus (HV) on lower limb neuromuscular control strategies during the sit-to-stand (STS) movement, and to evaluate the effects of Kinesio taping (KT) intervention on these control strategies in HV patients.

METHODS

We included 14 young healthy controls (HY), 13 patients in the HV group (HV), and 11 patients in the HV group (HVI) who underwent a Kinesio taping (KT) intervention during sit-to-stand (STS) motions. We extracted muscle and kinematic synergies from EMG and motion capture data using non-negative matrix factorization (NNMF). In addition, we calculated the center of pressure (COP) and ground reaction forces (GRF) to assess balance performance.

RESULTS

There were no significant differences in the numbers of muscle and kinematic synergies between groups. In the HV group, knee flexors and ankle plantar flexors were abnormally activated, and muscle synergy D was differentiated. Muscle synergy D was not differentiated in the HVI group.

CONCLUSION

Abnormal activation of knee flexors and plantar flexors led to the differentiation of module D in HV patients, which can be used as an indicator of the progress of HV rehabilitation. KT intervention improved motor control mechanisms in HV patients.

Pre-operative spinal cord perfusion quantified by DSC MRI as a predictor of post-operative prognosis in patients with cervical spondylotic myelopathy

OBJECTIVE

This study aims to investigate the potential of preoperative blood supply condition measured by dynamic susceptibility contract (DSC) MRI in prediction of postoperative outcomes for patients with cervical spondylotic myelopathy (CSM).

MATERIALS AND METHOD

Thirty-nine patients (Age: 61 ± 7, male: 23, female: 16) with CSM who underwent laminoplasty were enrolled. All patients received DSC MRI before the operation. Five parameters include Enhance, rEnhance, full width at half maxima (FWHM), Slope1 and Slope2 in DSC MRI, were calculated at all the compressed spinal cord segments. Clinical outcomes were evaluated by modified Japanese Orthopaedic Association (mJOA) scores. Patients were divided into two groups based on mJOA recovery rate of 5 years: good recovery (> 50%) or poor recovery (≤ 50%). The difference between two groups were compared. The value of DSC MRI to CSM was evaluated by logistic and receiver operating characteristic (ROC) curve analysis.

RESULTS

There were 26 patients in good recovery group and 13 patients in poor recovery group. The baseline characteristics, including age, gender, preoperative mJOA score, and smoking status showed no significant difference between the two groups (all p > 0.05). The FWHM was significantly higher in the poor recovery group (9.77 ± 2.78) compared to the good recovery group (6.64 ± 1.65) (p = 0.002). Logistic regression analysis indicated that an increased FWHM was a significant risk factor for poor prognosis recovery (p = 0.013, OR = 0.392, 95%CI: 0.187-0.822). The AUC of FWHM for ROC was 0.843 (95% CI: 0.710-0.975) with a p value of 0.001. In addition, an FWHM greater than 5.87, with a sensitivity of 92.3% and specificity of 69.2%, was found to be an independent risk factor for poor postoperative recovery in patients with CSM.

CONCLUSION

In this study, we successfully quantified the spinal cord blood supply condition by DSC MRI technique. We found that an increase in FWHM was an independent risk factor for poor postoperative recovery in CSM patients. Specifically, patients with FWHM > 5.87 have a poor postoperative recovery.

The mechanical properties of the spinal cord: a systematic review

BACKGROUND CONTENT

Spinal cord compression is a source of pathology routinely seen in clinical practice. However, there remain unanswered questions surrounding both the understanding of pathogenesis and the best method of treatment. This arises from limited real-life testing of the mechanical properties of the spinal cord, either through cadaveric human specimens or animal testing, both of which suffer from methodological, as well as ethical, issues.

PURPOSE

To conduct a review of the literature on the mechanical properties of the spinal cord.

STUDY DESIGN/SETTING

A systematic review of the literature on the mechanical properties of the spinal cord is undertaken.

PATIENT SAMPLE

All literature reporting the testing of the mechanical properties of the spinal cord.

OUTCOME MEASURES

Reported physiological mechanical properties of the spinal cord.

METHODS

The methodological quality of the studies has been assessed within the ARRIVE guidelines using the CAMARADES framework and SYRCLE's risk of bias tool. This paper details the methodologies and results of the reported testing.

RESULTS

We show that (1) the research quality of previous work does not follow published guidelines on animal treatment or risk of bias, (2) no standard protocol has been employed for sample preparation or mechanical testing, (3) this leads to a wide distribution of results for the tested mechanical properties, not applicable to the living human or animal, and (4) animal testing is not a good proxy for human application.

CONCLUSIONS

The findings summarize the sum of current knowledge inherent to the mechanical properties of the spinal cord and may contribute to the development of a physical model which is applicable to the living human for analysis and testing in a controlled and repeatable fashion. Such a model would be the basis for further clinical research to improve outcomes from spinal cord compression.

Assessing the predictive capability of machine learning models in determining clinical outcomes for patients with cervical spondylotic myelopathy treated with laminectomy and posterior spinal fusion

BACKGROUND

Cervical spondylotic myelopathy (CSM) is a prevalent degenerative condition resulting from spinal cord compression and injury. Laminectomy with posterior spinal fusion (LPSF) is a commonly employed treatment approach for CSM patients. This study aimed to assess the effectiveness of machine learning models (MLMs) in predicting clinical outcomes in CSM patients undergoing LPSF.

METHODS

A retrospective analysis was conducted on 329 CSM patients who underwent LPSF at our institution from Jul 2017 to Jul 2023. Neurological outcomes were evaluated using the modified Japanese Orthopaedic Association (mJOA) scale preoperatively and at the final follow-up. Patients were categorized into two groups based on clinical outcomes: the favorable group (recovery rates ≥ 52.8%) and the unfavorable group (recovery rates < 52.8%). Potential predictors for poor clinical outcomes were compared between the groups. Four MLMs-random forest (RF), logistic regression (LR), support vector machine (SVM), and k-nearest neighborhood (k-NN)-were utilized to predict clinical outcome. RF model was also employed to identify factors associated with poor clinical outcome.

RESULTS

Out of the 329 patients, 185 were male (56.2%) and 144 were female (43.4%), with an average follow-up period of 17.86 ± 1.74 months. Among them, 267 patients (81.2%) had favorable clinical outcomes, while 62 patients (18.8%) did not achieve favorable results. Analysis using binary logistic regression indicated that age, preoperative mJOA scale, and symptom duration (p < 0.05) were independent predictors of unfavorable clinical outcomes. All models performed satisfactorily, with RF achieving the highest accuracy of 0.922. RF also displayed superior sensitivity and specificity (sensitivity = 0.851, specificity = 0.944). The Area under the Curve (AUC) values for RF, Logistic LR, SVM, and k-NN were 0.905, 0.827, 0.851, and 0.883, respectively. The RF model identified preoperative mJOA scale, age, symptom duration, and MRI signal changes as the most significant variables associated with poor clinical outcomes in descending order.

CONCLUSIONS

This study highlighted the effectiveness of machine learning models in predicting the clinical outcomes of CSM patients undergoing LPSF. These models have the potential to forecast clinical outcomes in this patient population, providing valuable prognostic insights for preoperative counseling and postoperative management.

Utility of Zero-Echo time sequence as an adjunct for MR evaluation of degenerative disease in the cervical spine

OBJECTIVE

Determine the utility of ZTE as an adjunct to routine MR for assessing degenerative disease in the cervical spine.

METHODS

Retrospective study on 42 patients with cervical MR performed with ZTE from 1/1/2022 to 4/30/22. Fellowship trained radiologists evaluated each cervical disc level for neural foraminal (NF) narrowing, canal stenosis (CS), facet arthritis (FA), and presence of ossification of the posterior longitudinal ligament (OPLL). When NF narrowing and CS were present, the relative contributions of bone and soft disc were determined and a confidence level for doing so was assigned. Comparisons were made between assessments on routine MR without and with ZTE.

RESULTS

With ZTE added, bone contribution as a cause of NF narrowing increased in 47% (n = 110) of neural foramina and decreased in 12% (n = 29) (p =  < 0.001). Bone contribution as a cause of CS increased in 25% (n = 33) of disc levels and decreased in 10% (n = 13) (p = 0.013). Confidence increased in identifying the cause of NF narrowing (p =  < 0.001)) and CS (p = 0.009) with ZTE. The cause of NF narrowing (p = 0.007) and CS (p = 0.041) changed more frequently after ZTE was added when initial confidence in making the determination was low. There was no change in detection of FA or presence of OPLL with ZTE.

CONCLUSION

Addition of ZTE to a routine cervical spine MR changes the assessment of the degree of bone involvement in degenerative cervical spine pathology.

Is Upper Extremity or Lower Extremity Function More Important for Patient Satisfaction? An Analysis of 24-Month Outcomes from the QOD Cervical Spondylotic Myelopathy Cohort

STUDY DESIGN

Retrospective analysis of a prospective, multicenter registry.

OBJECTIVE

To assess whether upper or lower limb mJOA improvement more strongly associates with patient satisfaction after surgery for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

The modified Japanese Orthopaedic Association (mJOA) is commonly used to assess functional status in patients with CSM. Patients present with upper and/or lower extremity dysfunction, and it is unclear whether improvement in one and/or both symptoms drives postoperative patient satisfaction.

METHODS

This study utilizes the prospective Quality Outcomes Database (QOD) CSM data set. Clinical outcomes included mJOA and North American Spine Society (NASS) satisfaction. The upper limb mJOA score was defined as upper motor plus sensory mJOA, and the lower limb mJOA as lower motor plus sensory mJOA. Ordered logistic regression was used to determine whether upper or lower limb mJOA was more closely associated with NASS satisfaction, adjusting for other covariates.

RESULTS

Overall, 1141 patients were enrolled in the QOD CSM cohort. In all, 780 had both preoperative and 24-month mJOA scores, met inclusion criteria, and were included for analysis. The baseline mJOA was 12.1±2.7, and postoperatively, 85.6% would undergo surgery again (NASS 1 or 2, satisfied). Patients exhibited mean improvement in both upper (baseline:3.9±1.4 vs. 24 mo:5.0±1.1, P<0.001) and lower limb mJOA (baseline:3.9±1.4 vs. 24 mon:4.5±1.5, P<0.001); however, the 24-month change in the upper limb mJOA was greater (upper:1.1±1.6 vs. lower:0.6±1.6, P<0.001). Across 24-month NASS satisfaction, the baseline upper and lower limb mJOA scores were similar (pupper=0.28, plower=0.092). However, as satisfaction decreased, the 24-month change in upper and lower limb mJOA decreased as well (pupper<0.001, plower<0.001). Patients with NASS scores of 4 (lowest satisfaction) did not demonstrate significant differences from baseline in upper or lower limb mJOA (P>0.05). In ordered logistic regression, NASS satisfaction was independently associated with upper limb mJOA improvement (OR=0.81; 95% CI: 0.68-0.97; P=0.019) but not lower limb mJOA improvement (OR=0.84; 95% CI: 0.70-1.0; P=0.054).

CONCLUSIONS

As the magnitude of upper and lower mJOA improvement decreased postoperatively, so too did patient satisfaction with surgical intervention. Upper limb mJOA improvement was a significant independent predictor of patient satisfaction, whereas lower limb mJOA improvement was not. These findings may aid preoperative counseling, stratified by patients' upper and lower extremity treatment expectations.

LEVEL OF EVIDENCE

Level-III.

Dynamic Flexion-Extension Magnetic Resonance Imaging of the Cervical Spine: An Evolutionary Tool for Diagnosis and Management of Cervical Spondylotic Myelopathy

Dynamic problems need dynamic solutions. High motility of the cervical spine causes a common age-related degenerative condition called cervical spondylotic myelopathy (CSM), manifested by neurological impairments. An accurate and reliable diagnosis of CSM is crucial for determining appropriate management strategies. Traditional static magnetic resonance imaging (MRI) has been the gold standard for imaging CSM; however, it may not fully capture dynamic changes during neck movement. Dynamic flexion-extension (DFE) MRI is an innovative imaging technique that allows for real-time visualization of cervical spine motion. This review article aims to scrutinize the role of DFE MRI in assessing CSM, its added value to clinical implementations, and its limitations. Finally, by addressing the knowledge gaps, this survey sheds light on the road ahead to incorporate DFE MRI into a standard version of the practice.

A matched case-control study of early cervical spondylotic myelopathy based on diffusion magnetic resonance imaging

BACKGROUND

Early cervical spondylotic myelopathy (CSM) is challenging to diagnose and easily missed. Diffusion MRI (dMRI) has the potential to identify early CSM.

METHODS

Using diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and neurite orientation dispersion and density imaging (NODDI), a 1:1 matched case-control study was conducted to evaluate the potential of dMRI in identifying early CSM and assessing uncompressed segments of CSM patients. CSM patients and volunteers were matched by age and spinal location. The differences in dMRI parameters between groups were assessed by the paired t-test, the multicollinearity of the dMRI parameters was evaluated by the variance inflation factor (VIF), and the value of dMRI parameters in distinguishing controls from CSM patients was determined by logistic regression. The univariate t-test was used to analyse differences between CSM patients and volunteers in adjacent uncompressed areas.

RESULTS

In total, 56 CSM patients and 56 control volunteers were included. Paired t-tests revealed significant differences in nine dMRI parameters between groups. Multicollinearity calculated through VIF and combined with logistic regression showed that the orientation division index (ODI) was significantly positively correlated (r = 2.12, p = 0.035), and the anisotropic water fraction (AWF) was significantly negatively correlated (r = -0.98, p = 0.015). The fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), isotropic volume fraction (ISOVF), ODI, and AWF were significantly different in the upper and lower uncompressed areas at all ages.

CONCLUSION

dMRI can noninvasively identify early CSM patients and potentially identify the extent of CSM lesions involving the cervical spinal cord.

CRITICAL RELEVANCE STATEMENT

Diffusion MRI (dMRI) can identify early cervical spondylotic myelopathy (CSM) and has the potential to help determine the extent of CSM involvement. The application of dMRI can help screen for early CSM and develop clinical surgical and rehabilitation treatment plans.

KEY POINTS

• Diffusion MRI can differentiate between normal and early-stage cervical spondylotic myelopathy patients. • Diffusion MRI has the ability to identify the extent of spinal cord involvement in cervical spondylotic myelopathy. • Diffusion MRI enables the early screening of cervical spondylotic myelopathy and helps guide clinical treatment.

Shenqisherong pill ameliorates neuronal apoptosis by inhibiting the JNK/caspase-3 signaling pathway in a rat model of cervical cord compression

ETHNOPHARMACOLOGICAL RELEVANCE

The Shenqisherong (SQSR) pill is an empirical prescription of traditional Chinese medicine (TCM), which originated from the National Chinese Medical Science Master, Shi Qi. It has been widely used in the treatment of cervical spondylotic myelopathy (CSM) and promote the recovery of spinal cord function, but underlying molecular mechanism remains unclear.

AIM OF THE STUDY

The objective of this study was to confirm the neuroprotective effects of the SQSR pill.

MATERIALS AND METHODS

A rat model of chronic compression at double-level cervical cord was used in vivo. The protective role of SQSR pill on CSM rats was measured by Basso, Beattie, and Bresnahan (BBB) locomotor scale, inclined plane test, forelimb grip strength assessment, hindlimb pain threshold assessment, and gait analysis. The levels of reactive oxygen species (ROS) were examined by Dihydroethidium (DHE) staining and 2',7'-Dichlorofluorescein (DCF) assay, and apoptosis was detected by TdT-mediated dUTP nick-end labeling (TUNEL) assay. The expression of apoptosis proteins was evaluated by immunofluorescence staining and Western blot.

RESULTS

SQSR pill could facilitate locomotor function recovery in rats with chronic cervical cord compression, reduce local ROS in the spinal cord and downregulate the c-Jun-N-terminal kinase (JNK)/caspase-3 signaling pathway. In addition, the SQSR pill could protect primary rat cortical neurons from glutamate-treated toxicity in vitro by reducing the ROS and downregulating the phosphorylation of JNK and its downstream factors related to neuronal apoptosis meditated by the caspase cascade. Then, the neuroprotective effect was counteracted by a JNK activator.

CONCLUSIONS

Together, SQSR pill could ameliorate neuronal apoptosis by restraining ROS accumulation and inhibiting the JNK/caspase-3 signaling pathway, indicating that SQSR pill could be a candidate drug for CSM.

Comparison of efficacy between endoscope-assisted anterior cervical discectomy and fusion (ACDF) and open ACDF in the treatment of single-segment cervical spondylotic myelopathy

BACKGROUND

In this study, we compared the clinical efficacy of endoscope-assisted anterior cervical discectomy and fusion (ACDF) with open ACDF in the treatment of single-segment cervical spondylotic myelopathy.

METHODS

A retrospective analysis was performed on 52 patients with single-segment cervical spondylotic myelopathy between June 2021 and February 2022, including 33 males and 19 females, with a mean age of 58.42 ± 9.26) years. Among them, 28 patients were treated with endoscope-assisted ACDF (Group A), including 2 cases of C4/5 segment, 16 cases of C5/6 segment, and 10 cases of C6/7 segment; 24 patients were treated with open ACDF (Group B), including 4 cases of C4/5 segment, 11 cases of C5/6 segment, and 9 cases of C6/7 segment. The operation time, intraoperative blood loss, hospital stay, and complications were recorded and compared between the two groups. The Visual Analogue Scale (VAS) and the Japanese Orthopaedic Association (JOA) score were used for clinical evaluation during the follow-up in the 1st month and 3rd month after surgery, and at the final follow-up.

RESULTS

The 52 patients were followed up on average for 13.04 months (12-17 months). The operation time in Group A and Group B was (105.18 + 8.66) minutes and (81.88 + 6.05) minutes, the intraoperative blood loss was (84.29 + 13.45) mL and (112.92 + 17.81) mL, and the hospital stay was (6.75 + 1.29) days and (7.63 + 1.41) days, respectively. The difference between the two groups was statistically significant (P < 0.05). The VAS and JOA scores in the 1st month and the 3rd month after surgery and the last follow-up significantly improved in both groups compared with those before surgery (P < 0.05). The VAS and JOA scores of Group A in the 1st month, 3rd month after surgery, and the last follow-up were better than those in Group B (P < 0.05). The complication rate in Group A was 7% (2/28), which was not significantly different from the 17% (4/24) in Group B (P > 0.05).

CONCLUSION

Both endoscope-assisted ACDF and open ACDF can achieve satisfactory clinical efficacy in the treatment of single-segment cervical spondylotic myelopathy. Although the operation time of endoscope-assisted ACDF is prolonged, it has the advantages of clear vision, thorough decompression, less blood loss, and reduced risk of nerve damage, and is worthy of clinical promotion and application.

Subclinical respiratory dysfunction and impaired ventilatory adaptation in degenerative cervical myelopathy

Degenerative cervical myelopathy (DCM) is a debilitating neurological condition characterized by chronic compression of the cervical spinal cord leading to impaired upper and lower limb function. Despite damage to areas of the cervical spinal cord that house the respiratory network, respiratory dysfunction is not a common symptom of DCM. However, DCM may be associated with respiratory dysfunction, and this can affect the ventilatory response to respiratory challenges during emergence from anesthesia, exercise, or pulmonary disease. Surgical spinal cord decompression, which is the primary treatment for DCM, leads to improved sensorimotor function in DCM; yet its impact on respiratory function is unknown. Here, using a clinically relevant model of DCM, we evaluate respiratory function during disease progression and assess adaptive ventilation to hypercapnic challenge before and after surgical intervention. We show that despite significant and progressive forelimb and locomotor deficits, there was no significant decline in eupneic ventilation from the early to late phases of spinal cord compression. Additionally, for the first time, we demonstrate that despite normal ventilation under resting conditions, DCM impairs acute adaptive ventilatory ability in response to hypercapnia. Remarkably, akin to DCM patients, surgical decompression treatment improved sensorimotor function in a subset of mice. In contrast, none of the mice that underwent surgical decompression recovered their ability to respond to hypercapnic ventilatory challenge. These findings underscore the impact of chronic spinal cord compression on respiratory function, highlighting the challenges associated with ventilatory response to respiratory challenges in individuals with DCM. This research highlights the impact of cervical spinal cord compression on respiratory dysfunction in DCM, as well as the persistence of adaptive ventilatory dysfunction after surgical spinal cord decompression. These results indicate the need for additional interventions to enhance recovery of respiratory function after surgery for DCM.

Flail arm syndrome due to duplication mutations in the SMN1 gene: A case report

RATIONALE

Flail arm syndrome (FAS) only involves the upper limbs early stage and manifests as proximal weakness and atrophy of both upper limbs and decreased tendon reflexes. As a benign variant type of amyotrophic lateral sclerosis, FAS progresses slowly, with no lower motor neuron signs in the lower limbs or bulbar muscles within 12 months after onset.

PATIENT CONCERNS

A 49-year-old male patient was admitted to the hospital with a 15-month history of proximal weakness and muscle atrophy in both upper limbs. His other symptoms and signs were not obvious.

DIAGNOSES

Gene test results indicated that there were duplication mutations in the exon 7 to 8 region of the SMN1 gene.

LESSONS

The abnormal duplication of exons 7 and 8 of the SMN1 gene in this patient may increase the risk of FAS. Further studies are needed to identify the dominant genes and genetic factors causing males to be susceptible to FAS.