Introduction
Postoperative C5 palsy is characterized by deltoid motor weakness, often accompanied by variable pain and sensory symptoms [1–5]. The biceps may also be involved. Scoville [1] and Stoops and King [5] were the first to report postoperative C5 palsy following posterior cervical decompression. Subsequent literature has documented its occurrence following anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy with fusion, laminoplasty, and laminectomy with fusion [2–10]. Various mechanisms have been proposed to explain postoperative C5 motor palsies, including spinal cord reperfusion injury, ischemia, direct trauma, thermal injury, foraminal stenosis, and traction on the C5 nerve root due to spinal cord drift-back [2,3,9,11–16]. Recovery from postoperative C5 palsy is generally considered favorable, though it remains variable among patients [17]. Thompson et al. [10] reported that only 54% of patients achieved complete symptom resolution, while 17% displayed no recovery.
Despite the existence of extensive literature on postoperative C5 motor palsy, spontaneous cases occurring in the absence of prior cervical spine surgery remain poorly understood. In our clinical experience, we have encountered patients with new-onset weakness of the deltoid, and in some cases, the biceps brachii, without any history of previous surgical intervention. We refer to these patients as having a de novo C5 palsy. Unlike typical cervical radiculopathies involving other root levels, these patients predominantly present with motor symptoms [18–20]. Their etiology can be confirmed by imaging that demonstrates intrinsic spinal pathology with foraminal stenosis, spinal cord compression, or a combination of both. However, the literature characterizing the diagnosis and effective treatment of de novo C5 palsy remains limited. Therefore, this study aims to evaluate the presentation, imaging findings, treatment approaches, and clinical outcomes of surgically managed de novo C5 palsies.
Materials and Methods
This study was conducted by the principles of the Declaration of Helsinki. The study’s protocol was reviewed and approved by the Institutional Review Board (IRB) of Emory University (IRB approval no., MOD001-STUDY00005700). A waiver of informed consent was obtained before initiation of the study. Following IRB approval, a retrospective chart review was conducted to identify patients who presented to a single surgeon with de novo C5 motor palsy and met the following inclusion criteria: (1) new onset C5 palsy secondary to cervical spine pathology; (2) deltoid muscle strength less than 3/5 (unable to perform antigravity); and (3) radiographic evidence of ipsilateral C4–5 foraminal stenosis and/or spinal cord compression at C4–5 levels. Patients were excluded if they had a history of previous cervical surgery or deltoid muscle weakness resulting from rotator cuff injury or other extrinsic shoulder pathology.
The senior author graded each patient’s upper extremity motor function using the scale shown in Table 1 during both preoperative and postoperative visits. Before surgery, the patients were also evaluated for signs of cervical myelopathy—including hyperreflexia, Hoffman’s sign, Babinski, clonus, and gait dysfunction—as well as for signs of cervical radiculopathy, including a positive Spurling maneuver. Patient-reported intake forms and medical charts were reviewed to identify symptoms of cervical myelopathy, such as gait disturbance, loss of fine motor skills, or bowel and/or bladder disturbance. Symptoms of cervical radiculopathy, such as perceived radicular pain distribution, paresthesia, and/or upper extremity weakness, were also documented.
For each patient, the senior author reviewed all available radiographic imaging, including cervical anteroposterior, lateral, oblique, and dynamic X-rays, cervical computed tomography (with or without myelogram), and cervical magnetic resonance imaging (MRI). The imaging was assessed to identify central or ipsilateral pathology correlating with the C5 palsy. These areas of pathology were documented in the patient’s medical record.
Patient-reported clinical outcomes were collected, including the Neck Disability Index (NDI) score and Visual Analog Scale for pain. These outcome measures were collected preoperatively and at their regularly scheduled follow-up visits. Patients with incomplete follow-up data were contacted by phone to obtain scores at final follow-up.
All patients underwent surgery as planned, performed by the senior author, who selected the procedure for each patient based on radiographic pathology and clinical findings. Patients underwent one of the following procedures: ACDF, posterior cervical laminectomy and fusion (PCF) with or without laminoforaminotomy, or a cervical laminoplasty with or without laminoforaminotomy. In general, an anterior approach was selected for cases involving three or fewer levels of pathology or kyphosis. Laminoplasty was selected for patients with preserved lordosis and minimal to no axial pain. If a patient has three or more levels of cord compression with a flexible kyphosis, laminectomy with fusion was selected.
The patients were evaluated at regular postoperative intervals, including approximately 6 weeks, 3 months, and 1 year after surgery. C5 motor palsy was considered completely resolved if deltoid strength had returned to 5 out of 5 by the final follow-up appointment. Statistical analysis was performed using Fisher’s exact test ver. 9.4 (SAS Institute Inc., Cary, NC, USA) to compare resolution rates at final follow-up. A paired t-test was used to compare means between two groups, while analysis of variance was used to compare means among more than two groups.
Results
Clinical presentation
A total of 26 patients with 31 C5 motor palsies who met the inclusion and exclusion criteria were identified. These patients presented to a single attending surgeon over 14 years between May 2008 and April 2022. The cohort included 19 motor palsies (73%) in male patients, with five of these being bilateral, and 7 (27%) palsies in female patients (Table 2). The average patient age at the time of procedure was 60.7 years (range, 36–79 years). Sixteen patients (52%) demonstrated motor involvement without associated radicular pain, while the remaining 15 (48%) presented with both motor symptoms and radicular pain. All patients included in the study had preoperative deltoid weakness (strength <5/5), with a mean deltoid motor strength of 2.1. Twenty-seven of the 31 patients (87%) presented with concomitant deltoid and biceps weakness. Among patients with deltoid palsy, 10 (32%) had biceps brachii weakness with a motor grade of 2/5, while 17 (55%) had a biceps motor grade of 3 or 4/5. The mean preoperative biceps strength was 3.2. Eighteen patients (58%) exhibited signs and/or symptoms of myelopathy, including Hoffman’s sign in 13 (42%), hyperreflexia in 5 (16%), bowel or bladder symptoms in 6 (19%), loss of fine motor control in 13 (42%) and gait disturbances in 14 (45%).
Imaging
Significant ipsilateral foraminal stenosis at C4–5 was evident on MRI in 27 cases (87.1%) of the C5 palsies. MRI findings revealed spinal cord compression at C4–5 in 30 patients (97%), while significant central compression at C3–4 was present in 21 patients (68%). Twenty-three patients (88.5%) had both C4–5 cord compression and C4–5 foraminal stenosis. Ten patients (32.2%) demonstrated associated T2-spinal cord signal changes or myelomalacia at C3–4 or C4–5.
Timeline
The median time from symptom onset to presentation was 109.5 days (range, 11–6,551 days), while the mean time from presentation to surgical management was 35.7 days (range, 1–255 days). The average duration of final postoperative follow-up was 24.6 months (range, 1.3–91.9 months).
Deltoid strength
The mean preoperative deltoid motor grade was 2.1. Deltoid strength improved to a 5/5 grade in nine patients (29.0%) by 6 weeks, 22 (71.0%) by 6 months, and 26 patients (83.9%) by 1 year after surgery. All remaining deltoid palsies improved to motor strength of at least 3/5 at final follow-up, representing a significant clinical improvement from the preoperative baseline. The mean final deltoid motor grade significantly improved from 2.1 preoperatively to 4.7 at 1-year follow-up (p<0.0001) (Fig. 1).
Biceps strength
The mean preoperative bicep motor grade was 3.2. Among patients with concomitant biceps motor palsy, 12 (38.7%) had regained full biceps strength by 6 weeks, 19 (61.3%) by 6 months, and 24 (77.4%) by final follow-up. The mean bicep motor grade significantly improved from 3.2 preoperatively to 4.8 at the 1-year follow-up (p<0.0001) (Fig. 2).
C5 radicular pain
All 15 cases with preoperative C5 radicular symptoms experienced complete resolution of pain by the 6-week postoperative visit.
Patient-reported outcomes
The NDI improved from 39.26 preoperatively to 30.76 at first follow-up (p=0.22) and to 26.70 at the final follow-up (p<0.05). The Visual Analog Scale (VAS) pain score improved from 4.42 preoperatively to 3.29 at the first postoperative visit (p=0.55), and to 2.00 at final follow-up (p<0.05) (Table 3).
Surgical procedure
The surgical procedures included 16 (1.6%) ACDF, 6 (23.1%) laminoplasties, and 4 (15.4%) PCF (Table 4). In the ACDF group, 12.5% (2/16) of the deltoid palsies had regained full strength at 6 weeks, 81.3% (13/16) by 6 months, and 87.5% (14/16) by 1 year. 12.5% (2/16) of these deltoid palsies never reached full motor strength, but all did have at least 4 out of 5 deltoid motor strength at their final follow-up. Of the C5 palsies treated with laminoplasty, 62.5% (5/8) obtained full deltoid motor strength at 6 weeks, 87.5% (7/8) at 6 months, and 100% (8/8) at 1 year. Finally, in the PCF group, two of seven patients (28.6%) regained full strength by 6 weeks, another 2 (28.6%) by 6 months, and four patients (57.1%) by final follow-up. At final follow-up, five of seven patients (71.4%) with deltoid palsy treated with PCF had achieved at least 4 out of 5 deltoid motor strength.
Each surgical procedure resulted in a significant improvement in increased deltoid strength when comparing preoperative scores to those at the 1-year postoperative follow-up (Table 5). Deltoid scores significantly improved across all surgical groups when comparing preoperative values to those at the 1-year follow-up: ACDF cases improved from a mean of 2.25 to 4.88 (p<0.0001), laminoplasty from 2.25 to 5.00 (p<0.0001), and PCF from 1.71 to 4.29 (p<0.001). At the 6-week and 6-month postoperative follow-ups, PCF cases had significantly lower mean deltoid scores compared to the other surgical groups at the same postsurgical timepoints, 2.71 (p<0.05) and 3.00 (p<0.01), respectively. All surgical procedures produced statistically similar mean strength scores at 1-year follow-up.
Discussion
To our knowledge, this is the first study to describe the surgical management of de novo C5 palsies. Surgical intervention was associated with a high likelihood of recovery, with 84% of patients regaining full deltoid strength (5/5) and 97% achieving at least antigravity strength by the 1-year follow-up.
Notably, motor improvement occurred regardless of whether the decompressive procedure was performed via an anterior or posterior approach, suggesting that either approach may be appropriate for symptom relief. In this series, the choice of approach was based on several anatomical and clinical factors, including the location of the compression (e.g., foraminal versus spinal canal, anterior versus posterior lesion), number of levels involved, cervical sagittal alignment, and the presence or absence of neck pain. Given the relatively small sample sizes in each surgical group, statistical analysis to determine the superiority of one approach was not possible. It is unlikely that a single approach is best in all situations. However, just as the literature demonstrates that postoperative C5 palsy can occur following either anterior or posterior surgery, our findings indicate that both approaches can be effectively used to treat de novo C5 palsy [4].
In this study, de novo C5 palsy was associated with C4–5 foraminal stenosis in 87.1% of the cases. We also found that patients presenting with spinal cord compression at C3–4 or C4–5, without foraminal stenosis (12.9% of palsies) impinging on the C5 root, could still develop de novo C5 palsy. Therefore, we believe the observed palsies may result from both nerve root and spinal cord factors. Accordingly, the term “C5 palsy” may be somewhat of a misnomer, as the pathophysiology of the weakness may involve compression of both the nerve root and the spinal cord.
Siller et al. [19] reported on 31 patients with painless compressive motor radiculopathies at various levels who underwent either ACDF or PCF. They noted that the most common location for neuroforaminal stenosis was C4–5. Additionally, they reported that 87% of their patients had stable or improved motor function at final follow-up. They concluded that surgical decompression effectively treated patients with painless, progressive motor weakness. However, the previous study included patients with purely motor radiculopathies across all cervical levels. In contrast, our study specifically focused on patients with weakness in the C5 myotome. We differentiate this from cervical radiculopathy involving the C5 root because our patients exhibited predominant motor weakness without pain or sensory dysfunction, and some had only spinal cord compression without associated C5 root compression.
C5 motor palsy can be particularly disabling because the deltoid receives singular innervation, without contributions from nerves that originate from other nerve roots. Despite this, surgical management via either anterior or posterior approaches could lead to substantial and meaningful motor recovery in the vast majority of cases. Our findings highlight the close myotomal association between the deltoid and biceps brachii muscles. We observed biceps weakness in 87.1% of palsies, with 32.3% of patients unable to perform elbow flexion against gravity.
Parsonage-Turner syndrome, or brachial neuritis, can also present with shoulder weakness. However, the hallmark symptom is typically acute, severe pain in the shoulder region, followed by weakness [21,22]. Distinctively, the patients included in this study did not present in this way. Considering the findings of neurological compression in the cervical spine and the timing of postoperative motor function improvement following surgical decompression, we believe it is unlikely that any patients in this series had Parsonage-Turner syndrome.
Limitations of this study include its relatively small sample size, attributable to the rarity of the condition, as well as the heterogeneity of surgical procedures used to treat de novo C5 palsy. Although various procedures were performed, all involved decompression of the C5 root and/or spinal cord at levels affecting the C5 myotome. Another limitation is that this study does not evaluate the natural history of de novo C5 palsy. It is possible that the condition may improve spontaneously over time. However, spontaneous improvement seems unlikely in this cohort, as over two-thirds of the palsies had experienced palsy symptoms for more than 3 months before seeking medical evaluation, with a median time from symptom onset to initial presentation of 109.5 days. Although we cannot definitively recommend urgent surgery for this condition based on this study, we can conclude that surgery is associated with a high likelihood of improvement in patients who fail to respond to initial nonoperative care.
Conclusions
Our series demonstrates that patients with de novo C5 palsies who underwent surgical decompression experienced favorable motor outcomes. The results of this study may help set patient expectations for postoperative recovery and facilitate accurate informed consent. Improvement in motor function occurred with both anterior and posterior surgical approaches, suggesting that either approach can be employed depending on the clinical circumstances.
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