UNASSIGNED: Dropped head syndrome (DHS) is a relatively rare disease, and its potential relationship with drug exposure has been postulated but is poorly understood.
UNASSIGNED: This retrospective study evaluated the adverse event reports of DHS in the FDA adverse event reporting system （FAERS) between 1 January 2004, to 31 March 2021. Empirical Bayes Geometric Means (EBGM) and the lower 95% one-sided CI of EBGM were calculated to identify disproportionate reporting of DHS associated with drugs. In addition, published case reports were identified in the PubMed, Embase and Cochrane Library up to 5 August 2021.
UNASSIGNED: There were 193 reports of DHS in the FAERS, in which nervous system agents were most frequently reported, followed by antineoplastic and immunomodulating agents. Pramipexole, ropinirole, levodopa, pregabalin, rotigotine, cisplatin, imatinib and botulinum toxin showed disproportionality signal based each on more than 5 cases. Ten published DHS case reports were identified in the literature.
UNASSIGNED: Our study provides a more explicit profile on the occurrences and characteristics of DHS associated with drugs by analyzing the FAERS data and indicates that exposure of certain drug showed disproportionality signal with the increased DHS risk, which suggests the importance of further clinical and observational investigations.

Dropped head syndrome (DHS) can be divided into two types, the positive sagittal vertical axis (SVA) type and the negative SVA type. However, the cervical sagittal alignment of DHS including global sagittal spinal alignment and the typical cervical alignment of the types of DHS is still unclear. The purpose of this study was to clarify the character of cervical sagittal alignment of DHS and analyze the relationship between cervical sagittal alignment and global sagittal spinal alignment.
The subjects were 35 DHS patients (10 men, 25 women, mean 71.1 years old). They were divided into two groups: negative DHS (N-DHS group, SVA < 0 mm) and positive DHS group (P-DHS group, SVA ≥ 0 mm). As control, 28 age-matched cervical spondylosis patients (CS, 21 men, 7 women, mean 67.4 years old) were analyzed. The following parameters were measured on lateral global-spine standing radiographs: cervical SVA (C2-C7SVA), O-C2A (O-C2 angle), C2 slope (C2S), C2-7A (C2-7 angle), T1 slope (T1S) and C7SVA.
The results of measurements of each of the averaged sagittal alignment parameters were (CS, P-DHS, N-DHS): C2-7SVA(26.2 mm, 47.3 mm, 44.5 mm), O-C2 angle (35.0°, 37.1°, 39.3°), C2S (16.5°, 31.4°, 33.8°), C2-7A (9.3°, 9.9°, -16.6°), T1S (22.9°, 39.7°, 25.7°), C7SVA (35.3 mm, 51.0 mm, -43.1 mm). C2-C7SVA and C2S were significantly larger in both types of DHS compared to CS. Comparing P-DHS with N-DHS, C2-C7A and T1S were significantly smaller in N-DHS.
O-C2A did not differ significantly among CS, P-DHS and N-DHS. In DHS patients, C2-7SVA and C2S were significantly larger than those of CS regardless of the type of DHS. The typical cervical sagittal alignment of DHS was different between P-DHS and N-DHS. In P-DHS, C2-7A and T1S were larger than those in N-DHS and the imbalance of thoraco-lumbar alignment should be noted.

Dropped head syndrome (DHS) is manifested as the inability to maintain the head in an upright posture. It has been associated with a wide spectrum of myopathies and neurological conditions. Isolated neck extensor myopathy (INEM) is one of many potential causes of DHS. This is a case report of a 72-year-old man who presented with degenerative cervical spondylosis and DHS for 2 years. He had previously failed to achieve a positive outcome to medication, cervical collar and exercise rehabilitation. However, he was able to regain his voluntary head control after a 4-month chiropractic program. It is believed that INEM is caused by isolated myopathic changes from chronic injury and overloading of the cervical muscles. Cervical spondylosis has been attributed as the cause of DHS secondary to denervation of the cervical extensors. While INEM associated with degenerative spondylosis is not medically treatable, manipulative therapies may be adopted before considering surgical intervention.