Sono Takashi, Ijiri Kenta, Kakehi Kensaku, Masuda Soichiro, Shimizu Takayoshi, Murata Koichi, Matsuda Shuichi, Otsuki Bungo
Department of Orthopaedic Surgery Kyoto University Graduate School of Medicine Kyoto Japan.
JOR Spine. 2025 Jan 30;8(1):e70047. doi: 10.1002/jsp2.70047. eCollection 2025 Mar.
Dropped head syndrome (DHS) is characterized by weakness of the neck extensor muscles. However, few studies have assessed the cross-sectional areas (CSAs) of the cervical paraspinal muscles (CPM) and their anterior-posterior balance in DHS. This study aimed to elucidate the pathognomonic findings of DHS by comparing the CSAs and anterior-posterior balance of the CPM in patients with DHS and cervical spondylotic myelopathy (CSM), using magnetic resonance imaging (MRI).
We compared the CSAs and anterior-posterior balance of the CPM in patients with DHS and CSM using MRI. Patients with CSM were selected in an age- and sex-matched manner, using the propensity score. The longus colli (LC) muscle was selected as the anterior muscle; and the semispinalis cervicis (SSC), splenius capitis (SC), and multifidus muscles (MM) were selected as the posterior muscles. We calculated LC/SSC, LC/SC, LC/MM, and LC/(SSC + SC + MM), as indicators of neck muscle balance.
The DHS and the CSM cohort comprised 26 and 52 patients, respectively. Both cohorts had a mean age of 71-year-old. There were no significant differences in the CSAs and most of the indicators of neck balance between the two cohorts. However, the LC/SSC was significantly higher in the DHS cohort than that in the CSM cohort (40.3% and 29.1%, respectively; < 0.01).
Our study highlights a unique anterior-posterior imbalance in the CPM of DHS patients, differing from CSM patients. Strengthening the SSC muscle could be a key to preventing DHS progression.
低头综合征（DHS）的特征是颈部伸肌肌无力。然而，很少有研究评估DHS患者颈旁脊柱肌肉（CPM）的横截面积（CSA）及其前后平衡。本研究旨在通过磁共振成像（MRI）比较DHS患者和脊髓型颈椎病（CSM）患者CPM的CSA和前后平衡，以阐明DHS的特征性表现。
我们使用MRI比较了DHS患者和CSM患者CPM的CSA和前后平衡。采用倾向评分法按年龄和性别匹配选择CSM患者。选择颈长肌（LC）作为前部肌肉；选择颈半棘肌（SSC）、头夹肌（SC）和多裂肌（MM）作为后部肌肉。我们计算了LC/SSC、LC/SC、LC/MM和LC/（SSC+SC+MM），作为颈部肌肉平衡的指标。
DHS组和CSM组分别包括26例和52例患者。两组的平均年龄均为71岁。两组之间的CSA和大多数颈部平衡指标没有显著差异。然而，DHS组的LC/SSC显著高于CSM组（分别为40.3%和29.1%；<0.01）。
我们的研究突出了DHS患者CPM中独特的前后失衡，这与CSM患者不同。加强SSC肌肉可能是预防DHS进展的关键。
