Predisposing factors for poor outcome of surgery for cervical spondylotic amyotrophy: a multivariate analysis

Comparison of surgical outcomes for cervical radiculopathy by nerve root level

Cervical radiculopathy might affect finger movement and dexterity. Postoperative features and clinical outcomes comparing C8 radiculopathies with other radiculopathies are unknown. This prospective multicenter study analyzed 359 patients undergoing single-level surgery for pure cervical radiculopathy (C5, 48; C6, 132; C7, 149; C8, 30). Background data and pre- and 1-year postoperative neck disability index (NDI) and numerical rating scale (NRS) scores were collected. The C5-7 and C8 radiculopathy groups were compared after propensity score matching, with clinical significance determined by minimal clinically important differences (MCID). Postoperative arm numbness was significantly higher than upper back or neck numbness, and arm pain was reduced the most (3.4 points) after surgery among the C5-8 radiculopathy groups. The C8 radiculopathy group had worse postoperative NDI scores (p = 0.026), upper back pain (p = 0.042), change in arm pain NRS scores (p = 0.021), and upper back numbness (p = 0.028) than the C5-7 group. NDI achieved MCID in both groups, but neck and arm pain NRS did not achieve MCID in the C8 group. In conclusion, although arm numbness persisted, arm pain was relieved after surgery for cervical radiculopathy. Patients with C8 radiculopathy exhibited worse NDI and change in NRS arm pain score than those with C5-7 radiculopathy.

A review of electromyography techniques of the cervical paraspinal muscles

Electrodiagnosis for cervical radiculopathy often involves exploration of the cervical paraspinal muscles. Accurate and reproducible results require a technique with specific anatomic localization, direction of insertion, extent of insertion, scoring system for insertion, and criteria for determining abnormality. We sought to understand if a published technique met these criteria. A Medline search found 39 articles with original research and 10 review articles involving the cervical paraspinals. A library search found 19 textbooks since 2000, but 9 were not available. Only two studies were specific to the question. Neither had reproducible techniques and they contradicted each other. Studies in which the paraspinals were used for comparison or inclusion did not provide any specific technique. The review articles and textbooks typically met none of our criteria and the few that discussed technique at all provided no reproducible methods. Despite 80 years of electrodiagnostic testing, there is no useful, reproducible technique for exploring the cervical paraspinal muscles. Yet such a paraspinal mapping technique has proven invaluable in the lumbar region. For cervical electromyography to be of value, the next step is to understand the anatomy and propose a reproducible technique. Subsequent research will determine whether the neck muscles are helpful in the diagnosis of cervical radiculopathy. The absence of a valid reproducible cervical paraspinal technique impedes clinical and scientific understanding of cervical radiculopathy.

Surgical Outcomes of Full Endoscopic Posterior Cervical Foraminotomy for Proximal Cervical Spondylotic Amyotrophy

STUDY DESIGN

Retrospective analysis of case series.

PURPOSE

This study aimed to clarify the effects of full endoscopic posterior cervical foraminotomy (FPCF) on cervical spondylotic amyotrophy (CSA).

OVERVIEW OF LITERATURE

The method for decompressing the ventral nerve root and anterior horn (AH) in CSA is controversial.

METHODS

Patients without myelopathy who underwent FPCF for proximal CSA between 2017 and 2022 were analyzed. The outcome measure was the results of the manual muscle testing (MMT) of the deltoid and biceps. Preoperative nerve root and AH compression were evaluated by magnetic resonance imaging. The intervertebral foramen morphology and bony decompression extent were evaluated by computed tomography.

RESULTS

FPCF was performed at the C4/5 level and at the C4/5 and C5/6 levels in 14 and 11 patients, respectively. The width of the narrowest intervertebral foramen was significantly narrower on the affected side than on the healthy side at the C4/5 (2.5 mm vs. 3.6 mm) and operated C5/6 (1.9 mm vs. 3.1 mm) levels. AH compression occurred at the C4/5 and C5/6 levels in 28% and 21% of the patients, respectively. Bony decompression was performed laterally beyond the narrowest foramen at the C4/5 and C5/6 levels in 96% and 91% of the patients, respectively. Compared with patients without AH compression, in those with AH compression, the lamina was resected medially by an average of >1.7 mm and >3.6 mm at the C4/5 and C5/6 levels, respectively. Furthermore, 76% and 81% of the facet joint surfaces were preserved at the C4/5 and C5/6 levels, respectively. Postoperative MMT grade improvement was excellent, good, and fair in 64%, 20%, and 16% of the patients, respectively.

CONCLUSIONS

FPCF was effective for treating proximal CSA.

Sagittal sequence and clinical efficacy of cervical disc replacement and hybrid surgery in the treatment of cervical spondylotic myelopathy: a retrospective study

Background

Hybrid surgery (HS) combines anterior cervical discectomy and fusion (ACDF) with cervical disc replacement (CDR) is gradually being more frequently implemented, but there are few studies reporting the safety and effectiveness of hybrid surgery in three levels cervical spondylotic myelopathy.

Methods

The clinical and radiographic data of patients with three-segment cervical spondylosis, who underwent CDR, ACDF and HS in our hospital from February 2007 to February 2013 were analyzed. The Visual Analog Scale (VAS), Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) were used to evaluate the clinical efficacy post surgery. Cervical spine x-rays were conducted to assess ROM, CL, T1S and relevant outcomes.

Results

A total of 94 patients were included in the study: 26 in the CDR group, 13 in the HS1 group, 31 in the HS2 group, and 24 in the ACDF group. Most patients in the CDR group were younger. There was no difference in the follow-up duration, blood loss volume or surgery time (P > 0.05). Four groups reported improvements in JOA and NDI scores compared to baseline. There was no significant difference in the final JOA, final NDI or recovery rate among the 4 groups. The final ROM was smaller in the ACDF group than in the other 3 groups. There was no difference among the four groups in the final UROM, final LROM or their changes. There was no difference in the final T1S, final SVA or their change among the four groups. All groups showed similar changes in CL and T1S-CL.

Conclusions

There was no difference in the clinical outcomes of ACDF, CDR, or hybrid surgery. CDR can better preserve the mobility of the cervical spine. Neither CDR nor hybrid surgery was significantly advantageous over ACDF in restoring the sagittal sequence in patients with three-level CSM.

Prognostic factors for neurological outcome after anterior decompression and fusion for proximal-type cervical spondylotic amyotrophy - A retrospective analysis of 77 cases

BACKGROUND

Decompression through an anterior approach is theoretically effective for the surgical treatment of cervical spondylotic amyotrophy (CSA), because the pathology usually locates at the anterior side. However, most previous studies investigated posterior surgery or a mix of anterior surgery and posterior surgery in their investigation. Only a few small case series have investigated the surgical outcomes of anterior decompression and fusion (ADF). Therefore, we conducted a multicenter retrospective study that included patients who underwent ADF for proximal-type CSA.

METHODS

We analyzed the outcomes of 77 consecutive spinal surgeries performed on proximal-type CSA patients who underwent ADF. Preoperative and postoperative manual muscle tests (MMT) and the patients' backgrounds, radiological findings, and complications were reviewed. We divided the cases into two groups, good-outcome group (MMT improvement ≧ 2 or improved to MMT 5) and poor-outcome group (others) and evaluated the prognostic factors for outcomes.

RESULTS

Of the 77 patients, 48 (62%) showed good neurological outcome. Multiple compressive lesions at anterior horn (AH) and/or ventral nerve roots (VNRs) were detected in 66 patients (85.7%) on the magnetic resonance images. The patients with a single compressive lesion at VNR or AH tended to show good neurological recovery when compare to those with multiple lesions. Age and duration of symptoms were related to the poor outcome in univariate analysis. Duration of symptoms was an independent factor associated with postoperative neurological outcome. The cut-off value for poor outcome was 7.0 months for the symptom duration (sensitivity: 79%, specificity: 54%, area under the curve: 0.69).

CONCLUSIONS

Patients with proximal-CSA were more likely to have multiple compressive lesions at an AH and/or a VNR. The prognostic factor for poor neurological outcome was duration of symptoms of ≥7 months.

Intradural Neuroanatomy in the Cervical Spinal Canal: Importance of a New Anatomic Zone Division and Accurate Assessment of Neural Compression in Myeloradiculopathy Patients

This study defined different anatomic zones within the cervical spinal canal and provides detailed anatomical quantitative data for an accurate diagnosis of cervical spondylosis and a safe and effective anterior decompression surgery.

Atypical Proximal Cervical Spondylotic Amyotrophy: Case Report Demonstrating Clinical/Imaging Discrepancy

Purpose

The aim of this study was to present a novel case of unilateral proximal cervical spondylotic amyotrophy (CSA) with contralateral spinal cord compression, which is subject to misdiagnosis and missed diagnosis.

Background

CSA is the rare form of cervical spondylosis, which is characterized by severe muscle atrophy in the upper extremities. It can be classified in the proximal subtype and the distal subtype. The etiology, pathophysiology and treatment of CSA are still controversial.

Methods

A rare case of atypical proximal CSA, who presented with left shoulder and arm weakness, but cervical magnetic resonance imaging (MRI) showed large right paracentral disc herniation in the C4-5 level. Twelve weeks after undergoing anterior cervical discectomy and fusion technique in C4-5 level, the patient’s symptoms obviously recovered.

Conclusion

The opposite sides between disc herniation and clinical symptoms of upper extremity may be attributed to C5 ventral rootlet becoming stretched caused by spinal cord rotation or shift to the opposite side.

Surgical outcomes for distal-type cervical spondylotic amyotrophy: a multicenter retrospective analysis of 43 cases

PURPOSE

Distal-type cervical spondylotic amyotrophy (CSA) is a rare form of cervical spondylosis that causes muscle weakness of upper extremities. The pathophysiology and appropriate surgical method for the treatment of CSA are still controversial. We investigated clinical outcomes in surgically treated distal-type CSA.

METHODS

The authors executed an analysis of the outcomes of 43 consecutive spinal surgeries performed in distal-type CSA patients. The duration of symptoms, perioperative manual muscle test (MMT) results, radiological findings, and perioperative complications were reviewed. We compared surgical outcomes between different approaches and examined the factors related to poor outcomes (MMT improvement ≤ 0) after surgery.

RESULTS

The pathophysiology of CSA was mostly caused by a combination of multiple lesions in the anterior horn and/or nerve root. Nineteen of 29 patients (65.5%) who received anterior approach methods were included in the good outcome group (MMT improvement ≥ 1), whereas 7 of 14 patients (50.0%) in the posterior group were classified as good. In the anterior group, the mean MMT grade significantly improved from 2.6 to 3.4 (p = 0.0035) despite the higher rate of complications. The duration of symptoms was substantially associated with poor outcomes. The MMT grade significantly improved from 2.2 to 3.2 (p = 0.0118) in the < 6 months group. Cervical alignments and preoperative MMT grade were not statistically associated with poor outcomes.

CONCLUSIONS

Patients with poor outcomes had symptoms for a longer duration. We found tolerable clinical outcomes within 6 months from onset. The anterior approaches might be recommended because this procedure significantly improved MMT levels in the hands. These slides can be retrieved under Electronic Supplementary Material.

Cervical spondylotic amyotrophy: a systematic review

PURPOSE

Cervical spondylotic amyotrophy (CSA) is characterized by upper limb muscle weakness and atrophy, without sensory deficits. The pathophysiology of CSA has been attributed to selective injury to the ventral nerve root and/or anterior horn of the spinal cord. This review aimed to delineate the history of CSA and to describe the epidemiology, etiology, pathophysiology, classification, clinical features, radiological and electrophysiological assessment, diagnosis, differential diagnosis, natural history and treatment of CSA.

METHODS

A comprehensive search of PubMed, EMBASE, Cochrane library and Web of Science databases was conducted, from their inception to April 3, 2018.

RESULTS

Clinically, CSA is classified into three types: a proximal-type (involving the scapular muscles, deltoid and biceps), a distal-type (involving the triceps and muscles of the forearm and hand) and a diffuse-type (involving features of both the distal- and proximal-type). Diagnosis requires documentation of muscle atrophy, without significant sensory deficits, supported by careful neurological, radiological and neurophysiological assessments, with amyotrophic lateral sclerosis, Parsonage-Turner syndrome, rotator cuff tear and Hirayama disease being the principle differential diagnoses. Conservative management of CSA includes cervical traction, neck immobilization and physical therapy, with vitamin B12 or E administration being useful in some patients. Surgical treatment, including anterior decompression and fusion or laminoplasty, with or without foraminotomy, is indicated after conservative treatment failure. Factors associated with a poor outcome include the distal-type CSA, long symptom duration, older age and greater preoperative muscle weakness.

CONCLUSION

Although the disease process of CSA is self-limited, treatment remains challenging, leaving scope for future studies. These slides can be retrieved under Electronic Supplementary Material.

Clinical Features and Long-Term Surgical Outcomes of Patients with Cervical Spondylotic Amyotrophy

BACKGROUND

Cervical spondylotic amyotrophy (CSA) is not common. The clinical features and long-term surgical outcomes of patients with CSA are also unclear. We sought to summarize clinical features, assess long-term surgical outcomes, and determine the prognostic factors relevant for patients with CSA.

METHODS

A total of 136 patients with CSA who underwent anterior or posterior decompression during January 2001 to December 2012 were included. Their clinical and radiologic data were collected. The surgical outcome was evaluated using manual muscle test and improvements in the muscle strength. Correlations between the surgical outcome and various factors also were analyzed.

RESULTS

In total, 128 patients underwent anterior decompression and 8 patients underwent posterior decompression. At the final follow-up, the surgical outcome was significantly better after anterior decompression compared with that after posterior decompression. Statistical analyses showed the type of CSA, duration of symptoms, and association with ossification of the posterior longitudinal ligament were associated with a poor outcome after anterior surgery (P < 0.05).

CONCLUSIONS

Besides significant muscular atrophy in one upper extremity, CSA also occasionally presents with mild atrophy in the other upper extremity, sensory disturbance in the upper extremities, or hyperflexia in the lower extremities. Anterior decompression is generally effective in the treatment of patients with CSA. Preoperative duration of symptoms, type of CSA, and ossification of the posterior longitudinal ligament are important predictors for the surgical outcome.

High cord signals on magnetic resonance and other factors predict poor outcomes of cervical spine surgery: A review

Background:

High cord signals (HCS) on preoperative/postoperative T1, T1 gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), and T2 magnetic resonance (MR) studies, postoperative failure of HCS to regress and/or cord re-expansion, and a triangular cord configuration are poor prognostic factors for surgical patients with cervical spondylotic myelopathy (CSM).

Methods:

Here, we reviewed the negative prognostic import of high Grades/Types and more extensive locations of preoperative/postoperative HCS on T1, T1 Gd-DTPA, and T2 MR studies in surgical patients with CSM. Additional predictors of poor operative outcomes included postoperative failure of HCS to regress, cord re-expansion at the site of a HCS, and the triangular vs. teardrop or boomerang cord configuration. The Types/Grades of HCS on MR follow:Type/Grade 0 – no/absent signal changes; Type/Grade 1 – mild/light/fuzzy/obscure/low cord signal (LCS) changes; Type/Grade 2 – sharp/intense/well-defined HCS; and Type/Grade 3 – mixed/HCS. The definitions of location/extent of LCS/HCS were: focal (1 level), multifocal (with skip areas), and multisegmental (continuous over >1 segment), while cord configuration was categorized as triangular, teardrop, or boomerang.

Results:

On MR studies, preoperative/postoperative Types/Grades 0–1 changes correlated with better prognoses (e.g., improved Japanese Orthopedic Association (JOA) scores or Nurick Grades), while Types/Grades 2–3 correlated with poorer outcomes. Multiple poor prognostic indicators also included; failure of postoperative HCS on MR to regress (particularly if multisegmental), postoperative cord re-expansion at the site of a prior HCS, and triangular cord configuration.

Conclusions:

Grade/Types 2–3 HCS on T1, T1 Gd-DTPA, and T2-weighted MR images on preoperative/postoperative MR studies, failure of HCS to regress (multisegmental), cord re-expansion at the site of a prior HCS, and a triangular cord configuration (atrophy) all contributed to poorer outcomes for CSM surgery.