Predictive factors relating to prognosis of anterior decompressive surgery for proximal-type cervical spondylotic amyotrophy

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.

Evaluation of Anterior Decompression Surgical Outcomes of Proximal-Type Cervical Spondylotic Amyotrophy: A Retrospective Study

OBJECTIVE

To investigate the efficiency of anterior decompression on the proximal-type cervical spondylotic amyotrophy patients.

METHODS

This was a retrospective analysis. From January 2014 to November 2017, 21 patients with proximal-type cervical spondylotic amyotrophy (CSA) underwent anterior decompression. There were 15 males and 6 females, aged 35-73 years with an average of 51.62 years. All the patients underwent surgery of anterior decompression (ACDF or ACCF). Among them, 12 patients underwent C_4/5 single level ACDF, eight patients underwent C_4/5 and C_5/6 double level ACDF, and one patient underwent C5 anterior cervical corpectomy decompression and fusion surgery. Preoperative and postoperative clinical and radiologic parameters were assessed. The clinical examinations were reviewed, including muscle strength, neck disability index (NDI) score, cervical Japanese Orthopaedic Association (JOA) score, and improvement rate of manual muscle test (MMT) at the last follow-up. Preoperative spinal cord or nerve impingement was assessed by magnetic resonance imaging (MRI) or computed tomography (CT) myelography. Postoperative lateral X-ray radiographs were performed every 3 months after the surgery.

RESULTS

Severe preoperative muscle atrophy of the deltoid or biceps muscles occurred in 21 patients included in the study. All of them involve impingements of the ventral nerve root and/or the anterior horn according to MRI and CT myelography. The preoperative duration of symptoms averaged 8.4 months. The average follow-up for all patients was 13.2 months. At the final follow-up, all patients showed statistically significant improvements in muscle strength and NDI scores (P < 0.05, P < 0.05). For the deltoid muscles force and C-JOA scores, the average improvement rates were 66.49% ± 10.04% and 62.23% ± 9.23%, respectively. With respect to MMT, 12 proximal-type patients were graded excellent, six were good, and three were fair, and the overall improvement rate was 85.7%.

CONCLUSIONS

For proximal-type CSA patients with cervical radiculopathy, earlier anterior decompression surgery can achieve satisfactory results by significantly improving a patient's muscle strength and relieving compression symptoms.

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.

C5 pure motor spinal cord injury: A case with a rare manifestation of cervical spinal cord injury

We report an extremely rare case showing a fifth cervical spine (C5) level pure motor cervical spinal cord injury (SCI). A 55-year-old-man lost consciousness and fell into a bathtub. Immediately after regaining consciousness, the patient had right arm drop alone. He was referred to our department for investigation of right arm drop 4 months later. Neurological examination revealed motor weakness of the right deltoid muscle. MRI of the cervical spine revealed a C3-4 level central disc herniation compressing the spinal cord. An electromyogram study revealed bilateral neurogenic discharges in the deltoid, supraspinatus and infraspinatus muscles. We diagnosed a C5 segmental pure motor SCI. We chose conservative therapy for the present patient. At the latest follow-up visit, the patient showed modest recovery of motor weakness. Although it is unusual, this case illustrates the possibility that C5 segmental pure motor palsy can occur as one of the manifestations of cervical SCI.

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

The purpose of this study was to characterize risk factors for poor surgical outcome in patients with cervical spondylotic amyotrophy (CSA). We retrospectively reviewed 88 cases of CSA surgery and investigated age, sex, duration of symptoms, atrophy type, preoperative muscle power, signal changes on MRI, anterior horn (AH) or ventral nerve root (VNR) compression, compression levels, surgical approach and postoperative recovery. Fifty (56.8%) patients had good surgical outcome. Logistic regression, with poor outcome as dependent variable, showed independent risks associated with duration of symptoms (OR; 1 for symptom duration less than 3 months versus 3.961 [95% CI; 1.203–13.039, p = 0.024] for symptom duration of 3–6 months versus 18.724 [95% CI; 3.967–88.367, p < 0.001] for symptom duration greater than 6 months), compression type (OR; 1 for VNR versus 4.931 [95% CI; 1.457–16.685, p = 0.010] for AH versus 5.538 [95% CI; 1.170–26.218, p = 0.031] for VNR + AH), and atrophy type (OR; 1 for proximal type versus 6.456 [95% CI; 1.938–21.508, p = 0.002] for distal type). These findings suggest that a long duration of symptoms, AH or both AH and VNR compression, and distal type are risk factors for poor surgical outcome in patients with CSA.