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Dropped head syndrome (DHS) is presumably caused by focal myopathy in the cervical posterior muscles; however, distinguishable radiological features of the cervical spine in DHS remain unidentified. This study investigated the radiological features of the cervical spine in dropped head syndrome. The records of DHS patients and age- and sex-matched cervical spondylotic myelopathy (CSM) patients were reviewed. Cervical spinal parameters (C2-7, C2-4, and C5-7 angles) were assessed on lateral cervical spine radiographs. Quantitative radiographic evaluation of cervical spine degeneration was performed using the cervical degenerative index (CDI), which consists of four elements: disk space narrowing (DSN), endplate sclerosis, osteophyte formation, and listhesis. Forty-one DHS patients were included. Statistically significant differences were noted between the upper and lower cervical spine in the sagittal angle parameters on the neutral, flexion, and extension radiographs in DHS group, whereas no significant differences were observed in CSM group. CDI comparison showed significantly higher scores of DSN in C3/4, C4/5, C5/6, and C6/7; sclerosis in C5/6 and C6/7; and osteophyte formation in C4/5, C5/6, and C6/7 in DHS group than in CSM group. Comparison of listhesis scores revealed significant differences in the upper levels of the cervical spine (C2/3, C3/4, and C4/5) between two groups. Our results demonstrated that the characteristic radiological features in the cervical spine of DHS include lower-level dominant severe degenerative change and upper-level dominant spondylolisthesis. These findings suggest that degenerative changes in the cervical spine may also play a role in the onset and progression of DHS.

Background Most of the previous studies about the surgical treatment of dropped head syndrome (DHS) are small case series, and their primary outcome measures were cervical alignment parameters. Therefore, little is known about the associations between pre- and postoperative global sagittal alignment in the whole spine and the clinical outcomes of the surgical treatment of DHS. In this study, we investigated the surgical outcomes of DHS, including correction of cervical and global spinal sagittal alignment. Methods This study was a retrospective observational study. Fifteen patients with DHS who had undergone correction surgery were enrolled. Surgical outcomes, including complications and implant failures, were investigated. We assessed cervical alignment parameters as well as spinopelvic global alignment parameters, including pelvic incidence (PI), lumbar lordosis (LL), and C7-sacral sagittal vertical axis (SVA). We examined the changes in these parameters using pre- and posoperative whole spine lateral radiographs. The parameters were compared between the failure and nonfailure groups. Results Recurrence of sagittal imbalance and horizontal gaze difficulty was observed in 6 cases (40%). In all, 3 cases (20%) exhibited a distal junctional failure and required multiple surgeries with extension of fusion. Of all the radiographic parameters compared between the failure and nonfailure groups, significant differences were only observed in pre and postoperative SVA and PI-LL. Conclusions Our results suggest that the global sagittal alignment parameters, including PI-LL and SVA, were different between the patients with failure and non failure, and these parameters might have notable impacts on surgical outcomes. Surgeons should consider PI-LL and SVA while determining the surgical course for patients with DHS.

OBJECTIVEThe purpose of this study was to compare the clinical results of revision interbody fusion surgery between lateral lumbar interbody fusion (LLIF) and posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) with propensity score (PS) adjustments and to investigate the efficacy of indirect decompression with LLIF in previously decompressed segments on the basis of radiological assessment.METHODSA retrospective study of patients who underwent revision surgery for recurrence of neurological symptoms after posterior decompression surgery was performed. Postoperative complications and operative factors were evaluated and compared between LLIF and PLIF/TLIF. Moreover, postoperative improvement in cross-sectional areas (CSAs) in the spinal canal and intervertebral foramen was evaluated in LLIF cases.RESULTSA total of 56 patients (21 and 35 cases of LLIF and PLIF/TLIF, respectively) were included. In the univariate analysis, the LLIF group had significantly more endplate injuries (p = 0.03) and neurological deficits (p = 0.042), whereas the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), surgical site infections (SSIs) (p = 0.02), and estimated blood loss (EBL) (p < 0.001). After PS adjustments, the LLIF group still showed significantly more endplate injuries (p = 0.03), and the PLIF/TLIF group demonstrated significantly more dural tears (p < 0.001), EBL (p < 0.001), and operating time (p = 0.04). The PLIF/TLIF group showed a trend toward a higher incidence of SSI (p = 0.10). There was no statistically significant difference regarding improvement in the Japanese Orthopaedic Association scores between the 2 surgical procedures (p = 0.77). The CSAs in the spinal canal and foramen were both significantly improved (p < 0.001).CONCLUSIONSLLIF is a safe, effective, and less invasive procedure with acceptable complication rates for revision surgery for previously decompressed segments. Therefore, LLIF can be an alternative to PLIF/TLIF for restenosis after posterior decompression surgery.

Interpretation of thoracic spine radiographs is difficult because they cannot clearly depict the vertebrae due to overlap with soft tissues. This study aimed to evaluate whether thoracic spine radiographs obtained using the energy subtraction method could improve the accuracy of a diagnosis of thoracic osteolytic lesions. The authors analyzed 300 thoracic vertebrae from 25 patients with multiple myeloma who underwent thoracic spine radiography. All patients underwent thoracic spine radiography with 2 views. Two sets of images were prepared: computed radiography images (CR images) acquired using conventional processing parameters; and processed images for specifically visualizing bone, using the energy subtraction method (ES images). The CR images (CR group) and paired CR and ES images (CR+ES group) were interpreted in parallel by 5 orthopedic surgeons. The presence of osteolytic lesions was evaluated for each of the 12 thoracic vertebrae, and the sensitivity and specificity of the method were compared with computed tomography (CT), which is considered the gold standard. Subgroup analysis was also performed based on location. Osteolytic lesions were found on CT in 28 (9.3%) vertebrae of 12 patients. The overall sensitivities and specificities of the CR and CR+ES groups were 17.2% and 54.3%, respectively, and 95.6% and 98.0%, respectively, with statistically significant differences. Subgroup analysis showed particular improvement in the sensitivity for the CR+ES group in the middle thoracic spine compared with that at other locations. Thoracic spine radiographs generated using this method may improve the accuracy of diagnosis of thoracic osteolytic lesions. [ Orthopedics . 2021;44(1):e31–e35.]