Radiologic features of dropped head syndrome in the overall sagittal alignment of the spine

The Cross-Sectional Areas and Anterior-Posterior Balance of the Cervical Paraspinal Muscles in Dropped Head Syndrome and Cervical Spondylotic Myelopathy: A Propensity Score-Matched Analysis

Introduction

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).

Methods

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.

Results

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; p < 0.01).

Conclusions

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.

Radiological features of dropped head syndrome

BACKGROUND

This study aimed to elucidate the specificity of the radiological features of Dropped head syndrome (DHS) from both reginal and global aspects.

METHODS

We enrolled 53 patients with DHS (8 men, 45 women; mean age 73.5 years), and captured their lateral spinopelvic radiographs in standing position. We also selected 21 age- and sex-matched controls with cervical spondylosis. Radiological parameters were measured and compared between two groups. Compensatory and decompensatory sites were also listed for each patient.

RESULTS

Radiological factors such as sagittal vertical axis (SVA), clivo-axial angle (CAA), C2-7 angle, C2-7 SVA, anterior slippage of the vertebra, alignment. C1, C2, C3, C4, C5, C6 slopes, and T1 slope-C2-7 angle showed statistically significant differences between the groups. Multivariate logistic regression showed that SVA, C2-7 SVA, T1-slope-C2-7 angle, and C1 slope were the most important factors specific to DHS. Sole cervical spine and involvement of both cervical and thoracic spine accounted for 22% and 29% of the decompensatory sites in DHS respectively. Notably, 24% of the patients did not show decompensation of the cervical spine. While, 93% exhibited compensation at the craniovertebral junction. The thoracic spine contributed 70% to DHS compensation.

CONCLUSIONS

This study indicated the radiological features of DHS from both regional and global aspects. Compensatory and decompensatory DHS mechanisms varied among individuals. Compensation was likely to be developed at the neighboring sites, with the craniovertebral and thoracic junctions as the proximal and distal parts for DHS, respectively.

Magnetic resonance imaging findings in patients with dropped head syndrome

BACKGROUND

Dropped head syndrome (DHS) is difficult to diagnose only by clinical examination. Although characteristic images on X-rays of DHS have been studied, changes in soft tissue of the disease have remained largely unknown. Magnetic resonance imaging (MRI) is useful for evaluating soft tissue, and we therefore performed this study with the purpose of investigating the characteristic signal changes of DHS on MRI by a comparison with those of cervical spondylosis.

METHODS

The study involved 35 patients diagnosed with DHS within 6 months after the onset and 32 patients with cervical spondylosis as control. The signal changes in cervical extensor muscles, interspinous tissue, anterior longitudinal ligament (ALL) and Modic change on MRI were analyzed.

RESULTS

Signal changes of cervical extensor muscles were 51.4% in DHS and 6.3% in the control group, those of interspinous tissue were 85.7% and 18.8%, and those of ALL were 80.0% and 21.9%, respectively, suggesting that the frequency of signal changes of cervical extensor muscles, interspinous tissue and ALL was significantly higher in the DHS group (p < 0.05). The presence of Modic change of acute phase (Modic type I) was also significantly higher in the DHS group than in the control group (p < 0.001).

CONCLUSION

MRI findings of DHS within 6 months after the onset presented the characteristic signal changes in cervical extensor muscles, interspinous tissue, ALL and Modic change. Evaluation of MRI signal changes is useful for an objective evaluation of DHS.

Current Concepts of Cervical Spine Alignment, Sagittal Deformity, and Cervical Spine Surgery

There are not many reports on cervical spine alignment, and only a few analyze ideal surgical approaches and optimal amounts of correction needed for the various types of deformity. We comprehensively reviewed the present literature on cervical spinal deformities (with or without myelopathy) and their surgical management to provide a framework for surgical planning. A general assessment of the parameters actually in use and correlations between cervical and thoracolumbar spine alignment are provided. We also analyzed posterior, anterior, and combined cervical surgical approaches and indications for the associated techniques of laminoplasty, laminectomy and fusion, and anterior cervical discectomy and fusion. Finally, on the basis of the NDI, SF-36, VAS, and mJOA questionnaires, we fully evaluated the outcomes and measures of postoperative health-related quality of life. We found the need for additional prospective studies to further enhance our understanding of the importance of cervical alignment when assessing and treating cervical deformities with or without myelopathy. Future studies need to focus on correlations between cervical alignment parameters, disability scores, and myelopathy outcomes. Through this comprehensive literature review, we offer guidance on practical and important points of surgical technique, cervical alignment, and goals surgeons can meet to improve symptoms in all patients.

Conservative treatment for dropped head syndrome

PURPOSE

Previous reports on the outcome of conservative treatment for dropped head syndrome (DHS) are scarce. The purpose of this study was to elucidate the efficacy of conservative treatment for DHS and to identify possible predictive factors relating to the outcome.

METHODS

Among 76 DHS patients, conservative treatment (2-3 months collar application, active neck range of motion exercise, and occasional prescription of analgesics) succeeded in 17 patients (22.4%, group S, 4 male, 13 female, mean age 75.9 years). The treatment failed in the remaining 59 patients (group F). Clinical and radiological parameters were compared between the groups. Radiological findings of group S were compared between before treatment and at follow-up.

RESULTS

Duration of disease was 6.6 ± 9.3 months in group S and 20.0 ± 27.6 months in group F. C2-7 angle (degree), the incidence of anterior slippage of the vertebra (%), reducibility (%), and upper thoracic kyphosis angle (degree) in group S/F were - 19.2 ± 17.5/- 34.6 ± 26.6, 23.5/62.7, 100/52, and 6.7 ± 8.6/17.9 ± 13.7, respectively. C2-7 angles were - 19.2 ± 17.5 degrees at pre-treatment and 10.2 ± 20.7 degrees at follow-up. These differences were statistically significant.

CONCLUSIONS

The present study indicated that conservative treatment was successful in 22% of DHS patients, with improvement in their cervical kyphotic alignment. Shorter duration of disease, relatively smaller cervical kyphosis without anterior slippage of the vertebra, reducibility, and abundant compensation at the upper thoracic region were good indications for the success of conservative treatment.

Global Sagittal Spinal Compensation for Dropped Head Alignment

STUDY DESIGN

This is a retrospective radiographic study of a consecutive series of cases in patients with dropped head syndrome (DHS) at a single tertiary referral center.

OBJECTIVE

The aim was to clarify the compensation among parameters of spinal sagittal alignment in patients with DHS.

SUMMARY OF BACKGROUND DATA

The treatment strategy for DHS should vary according to the types of global sagittal spinal alignment. However, theoretical evidence in consideration of spinal sagittal compensation against the dropped head condition is lacking.

MATERIALS AND METHODS

One hundred sixteen patients diagnosed with isolated neck extensor myopathy were enrolled. Radiographic measurements were made, including parameters of spinal sagittal alignment. The patients were divided into three groups according to sagittal spinal balance: C7SVA (sagittal vertical axis) ≥ +50 mm (P-DHS; positive imbalanced DHS), -50 mm ≤C7SVA <+50 mm (B-DHS; balanced DHS), and C7SVA <-50 mm (N-DHS; negative imbalanced DHS). Correlations among the various spinal parameters were analyzed.

RESULTS

Among all types of DHS, there was no correlation between C2-C7 angle (C2-C7A) and T1 slope. In B-DHS, other correlations among the adjacent spinal segments were maintained. In N-DHS, there was no correlation between C2-C7A and TK, and in P-DHS, there was also no correlation between TK and lumbar lordosis.

CONCLUSIONS

The loss of compensation at the cervicothoracic junction was observed in all DHS types. B-DHS showed decompensation only at the cervicothoracic junction. N-DHS presented additional decompensation of the thoracic spine, and P-DHS showed decompensation between the thoracic and lumbar spine. Evaluation of global sagittal spinal balance is important for determining global spinal compensation associated with DHS and when considering treatment strategy.

Dropped head syndrome: a treatment strategy and surgical intervention

PURPOSE

The pathology of dropped head syndrome (DHS) is diverse, and reports of surgery for DHS are scarce. We aimed to describe surgery for DHS and to investigate the surgical outcomes thereof.

METHODS

We enrolled 40 consecutive patients (six males and 34 females; average age at surgery, 72.0 years) with DHS who underwent correction surgeries at a single institute. Short fusion (SF), with the extent of fixation mainly at the cervical region, was performed for 27 patients; long fusion (LF), involving the cervical and thoracic spine, for 13. Clinical and radiological outcomes were investigated, and factors analyzed using the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ).

RESULTS

All patients were able to gaze horizontally at the follow-up. Instances of five transient C5 palsy results, and five distal junctional kyphosis results were found, but no revisions were reported due to recurrence. Patients whose T1 slope-20° was smaller than the C2-7 angle postoperatively exhibited better clinical outcomes in the three domains of the JOACMEQ, regardless of the extent of fixation.

CONCLUSION

For cases where the T1 slope is relatively small, and approximately 10° of cervical lordosis is predicted to be obtained postoperatively, SF is appropriate. Alternatively, for cases with higher T1 slope, obtaining a cervical lordosis over 20° has a risk of postoperative complications. For such cases, it is an option to perform an LF involving the cervical and thoracic spine.

Evaluation of dynamic spinal alignment changes and compensation using three-dimensional gait motion analysis for dropped head syndrome

BACKGROUND CONTEXT

Dynamic kinematic evaluation of spino-pelvic alignment during gait using three-dimensional (3D) motion analysis has been proposed for adult spinal thoracolumbar deformity. That is because conventional full-spine radiographs cannot be used to evaluate dynamic factors. However, dynamic changes in spino-pelvic alignment during gait for dropped head syndrome (DHS) have not been studied using this approach.

PURPOSE

This study aimed to assess the dynamic changes in spinal-pelvic alignment during gait in patients with DHS using 3D motion analysis.

STUDY DESIGN

Retrospective review of collected radiographic and kinematic data.

PATIENT SAMPLE

Nineteen DHS patients with neck pain and/or anterior gaze disturbance.

OUTCOME MEASURES

Static spino-pelvic radiological alignment, dynamic spino-pelvic kinematic parameters and electromyogram (EMG) data.

METHODS

Center of gravity of the head - C7 sagittal vertical axis (CGH-C7 SVA), C2-C7 SVA, T1 slope; cervical lordosis (CL), C7SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence (PI) were assessed using full-spine radiographs in a standing position to assess static spino-pelvic alignment. The 3D gait motion analysis was conducted during gait. Dynamic kinematic parameters were divided into spinal segments: cervical (C-), thoracic (T-), lumbar (L-) and pelvis (P-). Each spinal segment coronal angle to the pelvic angle, each spinal segment sagittal angle to the pelvic angle and pelvic sagittal angle to the horizontal axis were assessed as dynamic spino-pelvic kinematic parameters. Trunk and lower limb muscle activity during gait were assessed using wireless surface EMG analysis. Dynamic spino-pelvic kinematic variables and muscle activity were compared between the first walking lap and the final lap during gait analysis. The change in dynamic kinematic parameters was correlated with static radiological alignment and electromyographic muscular activity change.

RESULTS

Cervical and thoracic anterior tilt increased significantly after an extended period of walking, indicating that dropped head worsened during gait. An increase of cervical anterior tilt during walking was significantly associated with decreased muscle activity in the cervical paraspinal muscles (r=-0.463, P<.05) and latissimus dorsi (r=-0.763, p<.01). Furthermore, significant correlations were found between a change in thoracic sagittal angle to pelvic angle and C7SVA (r=0.683, p<.01) and LL (r=-0.475, p<.05). This means that a larger C7SVA and smaller LL were associated with increased thoracic anterior tilt during gait.

CONCLUSIONS

The 3D motion analysis for DHS showed that cervical and thoracic anterior tilt significantly increased after extended walking, resulting in worsening of dropped head. Decreased muscle activity of the neck extensor muscles during gait suggests insufficient neck extensor muscle endurance, which was associated with increased cervical anterior tilt. A greater increase in the thoracic anterior tilt during gait was found in DHS patients with a larger C7SVA and smaller LL due to insufficient thoracolumbar compensation for the dropped head. Correction of the cervical spine alone would not be sufficient to improve dropped head in cases with increased thoracic anterior tilt during gait. The results suggest that C7SVA and LL are crucial parameters in the surgical strategy for DHS.

Dropped Head Syndrome Caused by Thoracolumbar Deformity: A Report of 3 Cases

CASE

We present 3 patients with dropped head syndrome (DHS) caused by thoracolumbar kyphotic deformity who were successfully treated with thoracolumbar corrective surgery only. After the surgery, their symptoms, neck pain, and horizontal gaze difficulty disappeared, and cervical kyphotic alignment was improved indirectly. At the final follow-up, the whole spinal alignment was maintained, and there was no recurrence of symptoms.

CONCLUSION

Surgeons should consider thoracolumbar spine deformity as the possible primary cause of typical DHS symptoms and recognize that thoracolumbar corrective surgery is an effective method for treating DHS patients with thoracolumbar deformity.

Surgical management of dropped head syndrome: A systematic review

Background:

Dropped head syndrome (DHS) is uncommon and involves severe weakness of neck-extensor muscles resulting in a progressive reducible cervical kyphosis. The first-line management consists of medical treatment targeted at diagnosing underlying pathologies. However, the surgical management of DHS has not been well studied.

Methods:

Here, we systematically reviewed the PubMed and Cochrane databases for DHS using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All relevant articles up to March 31, 2022, were analyzed. The patient had to be ≥18 years with DHS and had to have undergone surgery with outcomes data available. Outcomes measurements included neurological status, rate of failure (RF), horizontal gaze, and complications.

Results:

A total of 22 articles selected for this study identified 54 patients who averaged 68.9 years of age. Cervical arthrodesis without thoracic extension was performed in seven patients with a RF of 71%. Cervicothoracic arthrodesis was performed in 46 patients with an RF of 13%. The most chosen upper level of fusion was C2 in 63% of cases, and the occiput was included only in 13% of patients. All patients neurologically stabilized or improved, while 75% of undergoing anterior procedures exhibited postoperative dysphagia and/or airway-related complications.

Conclusion:

The early surgery for patients with DHS who demonstrate neurological compromise or progressive deformity is safe and effective and leads to excellent outcomes.

Analysis of the risk factors for increasing cervical sagittal vertical axis after cervical laminoplasty for cervical spondylotic myelopathy

INTRODUCTION

The cervical sagittal vertical axis (cSVA) as another aspect of cervical alignment been recognized as one of the important factors affecting the pain and disability outcomes of cervical spine surgery. The purpose of the present study was to analyze the risk factors for increasing cSVA after cervical laminoplasty for cervical spondylotic myelopathy (CSM).

MATERIALS AND METHODS

This retrospective study included 110 consecutive patients (68 males and 42 females, average age 72.6 years) who underwent laminoplasty for CSM between January 2007 and June 2018. We recorded the operative time, blood loss, Japanese Orthopaedic Association (JOA) score and the recovery rate. Radiological measurements were performed to analyze the following parameters: pre- and 1-year postoperative McGregor's slope (McGS), occiput to C2 Cobb angle (O-C2 angle), C2-C7 Cobb angle (C2-7 angle), T1-slope (T1S), C2-7 SVA (cSVA) and calculated the change (Δ). Patients were divided into two groups according to whether ΔcSVA was positive or negative. We also used Spearman's correlation coefficient and multiple regression analysis.

RESULTS

ΔC2-7 angle, ΔT1S-preoperative C2-7 angle, ΔO-C2 angle were different between the two groups significantly. Correlation analysis between the ΔcSVA and the various sagittal parameters showed some independent explanatory factors including the ΔC2-7 angle (r = - 0.25, p = 0.010), T1S-preoperative C2-7 angle (r = - 0.28, p = 0.004), postoperative O-C2 angle (r = 0.26, p = 0.007), ΔO-C2 angle (r = 0.37, p = 0.001). Multiple regression analysis revealed that ΔcSVA was associated with the T1S-preoperative C2-7 angle (β = - 0.25, p = 0.034) and ΔO-C2 angle (β = 0.32, p = 0.001).

CONCLUSIONS

The imbalance between T1S and preoperative C2-7 angle influences the change of cSVA after cervical laminoplasty. If cSVA increases postoperatively, the O-C2 angle increases to compensate and maintain the horizontal gaze.

Radiological features of cervical spine in dropped head syndrome: a matched case-control study

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Surgical Management of Post-Radiation, Dropped Head Spinal Deformity in Head and Neck Cancer Patients

BACKGROUND

Dropped head syndrome is a morbid condition, which affects daily functionality, causing pain and dysphagia and respiratory compromise. Reported causes of dropped head syndrome include neuromuscular disorders, iatrogenic from cervical spine surgery, idiopathic and post-radiation for head and neck cancers. Management of this spinal disorder remains challenging, as the complication rates are high. We present our series of 7 patients who underwent surgical correction of dropped head syndrome, all resulting from radiation for head and neck cancers.

METHODS

Retrospective review of 7 patients who underwent surgery between 2016 and 2019 for dropped head syndrome secondary to post-radiation cervical spine deformity. Clinical variables were obtained from medical records. Radiographic parameters pre- and post-surgery including T1 slope, sagittal vertical axis, and C2-7 cervical lordosis were examined.

RESULTS

Seven patients were included in the study, with an average age 69 years. Two patients underwent traction pre-operatively. Five patients had posterior fixation and fusion only and two patients had a combined anterior and posterior fixation and fusion. Overall, there was improvement in average pre/post-op SVA (6.96cm to 3.04cm), T1 slope (33.61^o to 24.34^o) and C2-7 lordosis (-21.65^o to -0.03^o).

CONCLUSION

Surgical correction of post-radiation dropped head spinal deformity involving anterior and posterior fixation with osteotomies provides improvement in functional and radiographic outcomes as shown in our series. These cases are technically challenging and have a high rate of peri-operative complications. Approaches must be tailored to the patient with attention to their specific surgical and radiation history.

Cervical sagittal alignment in patients with dropped head syndrome

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Global sagittal spinal alignment at cervical flexion in patients with dropped head syndrome

PURPOSE

Dropped head syndrome (DHS) is characterized by the passively correctable chin-on-chest deformity. The characteristic feature is emphasized in the cervical flexion position. The purpose of this study was to analyze the influence of cervical flexion on sagittal spinal alignment in patients with DHS.

METHODS

The study included 15 DHS subjects and 55 cervical spondylosis (CS) subjects as the control group. The following parameters were analyzed: cervical sagittal vertical axis (C-SVA), occipitoaxial angle (O-C2A), C2 slope (C2S), C2-C7 angle (C2-C7A), T1 slope (T1S), sagittal vertical axis, T1-T4 angle (T1-T4A), T5-T8 angle (T5-T8A), T9-T12 angle, lumbar lordosis, sacral slope, and pelvic tilt, in cervical flexion and neutral positions.

RESULTS

The values of C-SVA, O-C2A, C2S, and T1S were significantly different between CS and DHS at cervical neutral and flexion positions. C2-C7A showed significant difference in cervical neutral position, but the difference disappeared in flexion position. T1-T4A did not present a significant difference, but T5-T8A showed a difference in neutral and flexion positions.

CONCLUSIONS

Malalignment of DHS extended not only to cervical spine but also to cranio-cervical junction and thoracic spine, except T1-T4. It is known that global sagittal spinal alignment is correlated with adjacent parameters, although in DHS the reciprocal change was lost from cranio-cervical junction to the middle part of thoracic spine at cervical flexion.

Sagittal balance of the cervical spine: a systematic review and meta-analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the cervical sagittal parameters between patients with cervical spine disorder and asymptomatic controls.

METHODS

Two independent authors systematically searched online databases including Pubmed, Scopus, Cochrane library, and Web of Science up to June 2020. Cervical sagittal balance parameters, such as T1 slope, cervical SVA (cSVA), and spine cranial angle (SCA), were compared between the cervical spine in healthy, symptomatic, and pre-operative participants. Where possible, we pooled data using random-effects meta-analysis, by CMA software. Heterogeneity and publication bias were assessed using the I-squared statistic and funnel plots, respectively.

RESULTS

A total of 102 studies, comprising 13,802 cases (52.7% female), were included in this meta-analysis. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Funnel plot and Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the mean (SD) values were: T1 slope (degree), 24.5 (0.98), 25.7 (0.99), 25.4 (0.34); cSVA (mm), 18.7 (1.76), 22.7 (0.66), 22.4 (0.68) for healthy population, symptomatic, and pre-operative assessment, respectively. The mean value of the SCA (degree) was 79.5 (3.55) and 75.6 (10.3) for healthy and symptomatic groups, respectively. Statistical differences were observed between the groups (all P values < 0.001).

CONCLUSION

The findings showed that the T1 slope and the cSVA were significantly lower among patients with cervical spine disorder compared to controls and higher for the SCA. Further well-conducted studies are needed to complement our findings.

Mode of onset of dropped head syndrome and efficacy of conservative treatment

PURPOSE

The initial treatment of dropped head syndrome (DHS) is basically nonsurgical, but the mode of onset of DHS and efficacy of conservative treatment have not been fully clarified.

METHODS

The subjects were 38 DHS patients without neuromuscular disease (11 men and 27 women, average age 74.5 years). Cervical collar, physical therapy, and temporary medication for cervical pain were provided for all DHS patients. The following parameters were measured on lateral global spine standing radiographs: sagittal vertical axis (SVA), cervical sagittal vertical axis, C2-C7 angle, first thoracic slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence. According to the mode of onset of DHS, the subjects were classified into acute-onset group (<3 months) and chronic-onset group (≥3 months).

RESULTS

Acute- and chronic-onset DHS were observed in 20 and 18 patients, respectively. A history of cervical trauma was involved in nine and two cases of acute- and chronic-onset DHS, respectively. Acute-onset DHS included more balanced-SVA (B-SVA: -30 mm <SVA ≤40 mm) than chronic-onset DHS. In conservative cases, the recovery rate was better in acute-onset DHS with B-SVA. In acute-onset DHS treated conservatively, the recovery rate was significantly poor in cervical trauma cases.

CONCLUSIONS

Acute-onset DHS includes more balanced SVA and a history of cervical trauma, while acute-onset DHS without a history of cervical trauma has better prognosis by conservative treatment. Surgical indications for DHS should be carefully determined, and sufficient conservative treatment is essential.

Cervical Sagittal Alignment: Literature Review and Future Directions

Cervical alignment as a concept has come to the forefront for spine deformity research in the last decade. Studies on cervical sagittal alignment started from normative data, and expanded into correlation with global sagittal balance, prognosis of various conditions, outcomes of surgery, definition and classification of cervical deformity, and prediction of targets for ideal cervical reconstruction. Despite the recent robust research efforts, the definition of normal cervical sagittal alignment and cervical spine deformity continues to elude us. Further, many studies continue to view cervical alignment as a continuation of thoracolumbar deformity and do not take into account biomechanical features unique to the cervical spine that may influence cervical alignment, such as the importance of musculature connecting cranium-cervical-thoracic spine and upper extremities. In this article, we aim to summarize the relevant literature on cervical sagittal alignment, discuss key results, and list potential future direction for research using the '5W1H' framework; "WHO" are related?, "WHY" important?, "WHAT" to evaluate and "WHAT" is normal?, "HOW" to evaluate?, "WHEN" to apply sagittal balance?, and "WHERE" to go in the future?

Impact of Spinopelvic sagittal alignment on the surgical outcomes of dropped head syndrome: a multi-center study

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.

Establishment of a novel rehabilitation program for patients with dropped head syndrome: Short and intensive rehabilitation (SHAiR) program

The pathophysiology of dropped head syndrome (DHS) remains unknown, and its treatment algorithm and indication are not standardized. Here, we established a novel rehabilitation program, short and intensive rehabilitation program for DHS (SHAiR program), consisting of cervical paraspinal muscles exercise, range of motion exercise, cervical and thoracic mobilization, deep cervical flexor muscle exercise, hip lift exercise, anterior pelvic tilt exercise, and walking exercise. The aim of this study was to evaluate the clinical effectiveness of this program. We reviewed clinical outcomes for five consecutive patients with DHS who underwent the SHAiR program (SHAiR group). The outcomes were compared with those of other five patients with DHS who received exercise instruction (control group). Demographic data, the duration from onset of DHS, the apex of sagittal kyphosis on the lateral radiographs, and clinical outcomes including the ability to maintain normal horizontal gaze, chin brow vertical angle, and numerical rating scale (NRS) were evaluated at the initial visit and final follow-up at 7.5 months. There was no significant difference between the two groups in terms of demographic and radiographic data. The ability of horizontal gaze and NRS of cervical pain improved rapidly for all five patients in the SHAiR group as compared to no improvement for all patients in the control group. Rehabilitation for DHS was considered effective not only for localized rehabilitation such as exercise for training cervical extensor muscle function but also exercises for thoracolumbar posture improvement and the psoas muscle.

Overview of dropped head syndrome (Combined survey report of three facilities)

BACKGROUND

Dropped head syndrome (DHS) is a low prevalence and the clinical features remain unclear. The purpose of the present study was to clarify the general overview of DHS.

METHODS

The subjects were 67 consecutive DHS patients (17 men and 50 women; average age 72.9 ± 10.2 years) presenting difficulty of horizontal gaze in up-right position. The patients' background, global spinal alignment, clinical findings and treatment were analyzed.

RESULTS

The peak population of DHS was 75-79-year-old females. The comorbidities included Parkinson's disease in 9 cases, minor trauma in 9 cases, post-cervical operation in 3 cases, mental depression in 3 cases, malignant tumor in 3 cases, diabetes mellitus in 2 cases and rheumatoid arthritis in 2 cases. The C2-C7 cervical coronal vertical axis was distributed more to the right side (2.6 ± 12.8 mm). Regarding sagittal alignment, 24 cases (35.8%) showed negative balanced DHS (N-DHS) and 43 cases (64.2%) showed positive balanced DHS (P-DHS). There were significant differences in C2-C7 angle, T1S, LL and PI-LL between the two groups. Cervical or back pain was present in 62 cases (92.5%), and average numerical rating scale was 3.0 ± 2.6. Fourteen cases (20.9%) recovered (average 11.3 months), but 29 cases (43.3%) did not recover without surgery. Twenty-four cases (35.8%) underwent surgery, 20 for cervical spine and 4 for thoraco-lumbar spine, and horizontal gaze difficulty was improved in all patients post-surgery.

CONCLUSION

DHS was mainly observed in elderly women. About 20% of DHS patients recovered without surgical treatment. DHS was accompanied by scoliosis in 37.3% of the cases.

Dropped head syndrome due to neuromuscular disorders: Clinical manifestation and evaluation

In this article, we discuss the clinical approach to patients with dropped head syndrome and identify the various neuromuscular causes of dropped head syndrome including muscle, neuromuscular junction, peripheral nerve and motor neuron etiologies. We aim to increase awareness of recognition the entity of dropped head syndrome and factors that may predict response to immunomodulating therapy in dropped head syndrome.

An algorithmic strategy of surgical intervention for cervical degenerative kyphosis

PURPOSE

Correction surgery for cervical degenerative kyphosis (CDK) may carry a greater risk of causing neural complications such as spinal cord injury and C5 nerve palsy because spinal canal stenosis, osteoarthritis of the facet, and consequent foraminal stenosis may coexist with CDK. We have produced an algorithmic strategy of surgical intervention for CDK, and report the outcome.

METHODS

Thirty-one patients who underwent correction surgery for CDK, with a kyphotic angle of 20° or more (from 20 to 74) were involved. An algorithmic surgical strategy is shown. Clinical and radiological outcomes were examined amongst the groups.

RESULTS

Recovery rate of the JOA score was a mean of 44%. Preoperative kyphotic angle and correction angle were; 24.4°and 26.5°in P, 38.4°and 41.1°in AP, and 42.0°and 46.9°in PAP respectively. No spinal cord injury was found. Five cases of C5 nerve palsy occurred in P, and one in AP. Four cases of C5 palsy occurred in seven patients in PAP, although prophylactic foraminotomy was performed. All C5 palsy patients recovered fully at follow-up.

CONCLUSIONS

This study showed that our algorithmic surgical strategy for CDK is acceptable because we obtained good outcomes, and no catastrophic complications occurred. Although we did not intend to obtain excessive postoperative lordosis, we still had several incidence of C5 nerve palsy. We have to be aware of this incidence in PAP, which required a massive range of realignment. The incidence occurred even after we performed prophylactic foraminotomy, however, this procedure may lessen the severity of C5 palsy because those were all transient.