Investigation of the effectiveness of intermittent electromagnetic field stimulation for early internal cartilaginous ossification in prechondrocytic ATDC5 cells.

Pulsed electromagnetic field (PEMF) stimulation has been widely applied clinically to promote bone healing; however, its detailed mechanism of action, particularly in endochondral ossification, remains elusive, and long-term stimulation is required for its satisfactory effect. The aim of this study was to investigate the involvement of the mammalian target of rapamycin (mTOR) pathway in chondrocyte differentiation and proliferation using a mouse prechondroblast cell line (ATDC5), and establish an efficient PEMF stimulation strategy for endochondral ossification. The changes in cell differentiation (gene expression levels of aggrecan, type II collagen, and type X collagen) and proliferation (cellular uptake of bromodeoxyuridine [BrdU]) in ATDC5 cells in the presence or absence of rapamycin, an mTOR inhibitor, was measured. The effects of continuous and intermittent PEMF stimulation on changes in cell differentiation and proliferation were compared. Rapamycin significantly suppressed the induction of cell differentiation markers and the cell proliferation activity. Furthermore, only intermittent PEMF stimulation continuously activated the mTOR pathway in ATDC5 cells, significantly promoting cell proliferation. These results demonstrate the involvement of the mTOR pathway in chondrocyte differentiation and proliferation and suggest that intermittent PEMF stimulation could be effective as a stimulus for endochondral ossification during fracture healing process, thereby reducing stimulation time.

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.

A novel diagnostic examination for dropped head syndrome (DHS) (Prone position cervical extension test; DHS test).

BACKGROUND: Dropped head syndrome (DHS) is followed by severe cervical extension muscle weakness that results in chin-on chest deformity. However, maintaining a neutral cervical position can be temporarily possible, and the diagnosis of DHS might sometimes be difficult. The purpose of the present study is to examine a novel clinical test (DHS test) as the diagnostic utility for objective evaluation that focuses on cervical extension condition in the prone position. METHODS: One hundred subjects were diagnosed with isolated neck extensor myopathy (INEM)-DHS at our hospital (17 men and 83 women, mean age 75.0 ± 8.5 years), and 62 subjects were enrolled as age-matched controls. The DHS test consisted of three examinations; the first was "Ceiling gazing test" in standing position, the second was horizontal gazing in "Sphinx prone position test", and the third was horizontal gazing in "Hands and knees prone position test". We investigated the sensitivity and specificity of the DHS test for DHS. RESULTS: The patients showing positive in the INEM-DHS group were 63/100 in Ceiling gaze test, 73/100 in the Sphinx prone position test, and 91/100 in the Hands and knees prone position test. In the control group, 0/62 patients presented positive in the Ceiling gaze test, 4/62 in the Sphinx prone position test, and 0/62 in the Hands and knees prone position test. Sensitivity and specificity of the DHS test were 63.0%/100%, 73.0%/93.5%, and 91.0%/100% in the Ceiling gaze test, Sphinx position prone position test, and Hands and knees prone position test, respectively. CONCLUSION: The prone position cervical extension test (DHS test) would be useful as a novel objective diagnostic tool for INEM-DHS.

Prostaglandin E2 induces dual-specificity phosphatase-1, thereby attenuating inflammatory genes expression in human osteoarthritic synovial fibroblasts.

Characteristic features of osteoarthritis (OA) are joint pain and cartilage degeneration. The degeneration is caused by excess induction of matrix metalloproteinases (MMPs) and the pain is caused by nerve growth factor (NGF)-dependent nerve invasion into synovial tissue in addition to nociceptive pain by prostaglandin (PG)E2. The objective of this study was to clarify the suppressive mechanism of PGE2 on the regulation of MMPs and NGF by focusing on mitogen-activated protein kinases (MAPKs) and their endogenous phosphatase, dual-specificity phosphatase (DUSP)-1 in human synovial fibroblasts. PGE2 strongly increased DUSP-1 and suppressed IL-1ß-induced MAPKs phosphorylation. Inhibition of MAPKs by selective inhibitors differentially regulated the IL-1ß-induced expression of MMPs and NGF expression. IL-1ß-induced MAPKs phosphorylation was prolonged and enhanced in DUSP-1 knockdown cells and the expression of MMPs and NGF was also increased. This study revealed that PGE2 has novel biological activity that suppresses NGF and MMPs expression by inducing DUSP-1 expression.

Use of residual neural network for the detection of ossification of the posterior longitudinal ligament on plain cervical radiography.

Ossification of the posterior longitudinal ligament (OPLL) causes serious problems, such as myelopathy and acute spinal cord injury. The early and accurate diagnosis of OPLL would hence prevent the miserable prognoses. Plain lateral radiography is an essential method for the evaluation of OPLL. Therefore, minimizing the diagnostic errors of OPLL on radiography is crucial. Image identification based on a residual neural network (RNN) has been recognized to be potentially effective as a diagnostic strategy for orthopedic diseases; however, the accuracy of detecting OPLL using RNN has remained unclear. An RNN was trained with plain lateral cervical radiography images of 2,318 images from 672 patients (535 images from 304 patients with OPLL and 1,773 images from 368 patients of Negative). The accuracy, sensitivity, specificity, false positive rate, and false negative rate of diagnosis of the RNN were calculated. The mean accuracy, sensitivity, specificity, false positive rate, and false negative rate of the model were 98.9%, 97.0%, 99.4%, 2.2%, and 1.0%, respectively. The model achieved an overall area under the curve of 0.99 (95% confidence interval, 0.97-1.00) in which AUC in each fold estimated was 0.99, 0.99, 0.98, 0.98, and 0.99, respectively. An algorithm trained by an RNN could make binary classification of OPLL on cervical lateral X-ray images. RNN may hence be useful as a screening tool to assist physicians in identifying patients with OPLL in future setting. To achieve accurate identification of OPLL patients clinically, RNN has to be trained with other cause of myelopathy.

DUSP-1 Induced by PGE2 and PGE1 Attenuates IL-1ß-Activated MAPK Signaling, Leading to Suppression of NGF Expression in Human Intervertebral Disc Cells.

The molecular mechanism of discogenic low back pain (LBP) involves nonphysiological nerve invasion into a degenerated intervertebral disc (IVD), induced by nerve growth factor (NGF). Selective cyclooxygenase (COX)-2 inhibitors are mainly used in the treatment of LBP, and act by suppressing the inflammatory mediator prostaglandin E2 (PGE2), which is induced by inflammatory stimuli, such as interleukin-1ß (IL-1ß). However, in our previous in vitro study using cultured human IVD cells, we demonstrated that the induction of NGF by IL-1ß is augmented by a selective COX-2 inhibitor, and that PGE2 and PGE1 suppress NGF expression. Therefore, in this study, to elucidate the mechanism of NGF suppression by PGE2 and PGE1, we focused on mitogen-activated protein kinases (MAPKs) and its phosphatase, dual-specificity phosphatase (DUSP)-1. IL-1ß-induced NGF expression was altered in human IVD cells by MAPK pathway inhibitors. PGE2 and PGE1 enhanced IL-1ß-induced DUSP-1 expression, and suppressed the phosphorylation of MAPKs in human IVD cells. In DUSP-1 knockdown cells established using small interfering RNA, IL-1ß-induced phosphorylation of MAPKs was enhanced and prolonged, and NGF expression was significantly enhanced. These results suggest that PGE2 and PGE1 suppress IL-1ß-induced NGF expression by suppression of the MAPK signaling pathway, accompanied by increased DUSP-1 expression.

The factors related to the poor ADL in the patients with osteoporotic vertebral fracture after instrumentation surgery.

PURPOSE: Osteoporotic vertebral fracture (OVF) with nonunion or neurological deficit may be a candidate for surgical treatment. However, some patients do not show improvement as expected. Therefore, we conducted a nationwide multicenter study to determine the predictors for postoperative poor activity of daily living (ADL) in patients with OVF. METHODS: We retrospectively reviewed the case histories of 309 patients with OVF who underwent surgery. To determine the factors predicting postoperative poor ADL, uni- and multivariate statistical analyses were performed. RESULTS: The frequency of poor ADL at final follow-up period was 9.1%. In univariate analysis, preoperative neurological deficit (OR, 4.1; 95% CI, 1.8-10.3; P < 0.001), perioperative complication (OR, 3.4; P = 0.006), absence of preoperative bone-modifying agent (BMA) administration (OR, 2.7; P = 0.03), and absence of postoperative recombinant human parathyroid hormone (rPTH) administration (OR, 3.9; P = 0.006) were significantly associated. In multivariate analysis, preoperative neurological deficit (OR, 4.6; P < 0.001), perioperative complication (OR, 3.4; P = 0.01), and absence of postoperative rPTH administration (OR, 3.9; P = 0.02) showed statistical significance. CONCLUSIONS: Preoperative neurological deficit, perioperative complication, and absence of postoperative rPTH administration were considered as predictors for postoperative poor ADL in patients with OVF. Neurological deficits and complications are often inevitable factors; therefore, rPTH is an important option for postoperative treatment for OVF. These slides can be retrieved under Electronic Supplementary Material.

Intermittent pulsed electromagnetic field stimulation activates the mTOR pathway and stimulates the proliferation of osteoblast-like cells.

Pulsed electromagnetic fields (PEMFs) have been shown to be a noninvasive physical stimulant for bone fracture healing. However, PEMF stimulation requires a relatively long period of time and its mechanism of action has not yet been fully clarified. Recently, the mammalian target of rapamycin (mTOR) pathway has been shown to be involved in bone formation. This study aimed to investigate the effects of PEMFs on osteoblastic MC3T3-E1 cells by examining various cellular responses including changes in the mTOR pathway. Continuous PEMF stimulation induced a transient phosphorylation of the mTOR pathway, whereas intermittent PEMF stimulation (1 cycle of 10 min stimulation followed by 20 min of stimulation pause) revitalized the reduced phosphorylation. Moreover, PEMF stimulation stimulated cell proliferation (bromodeoxyuridine incorporation) rather than differentiation (alkaline phosphatase activity), with a more notable effect in the intermittently stimulated cells. These results suggest that intermittent PEMF stimulation may be effective in promoting bone fracture healing by accelerating cell proliferation, and in shortening stimulation time. Bioelectromagnetics. 2019;40:412-421. © 2019 Bioelectromagnetics Society.

Impact of pelvic incidence on change in lumbo-pelvic sagittal alignment between sitting and standing positions.

PURPOSE: Lumbo-pelvic sagittal alignment is affected by pelvic incidence (PI), and the PI represents the compensatory capacity of lumbo-pelvic sagittal alignment. The purpose of this study was to analyze changes in lumbo-pelvic sagittal alignment between the standing and sitting positions and to analyze its association with PI. METHODS: This study included 253 subjects (160 men and 93 women; age 53.6 ± 7.4 years). The subjects were divided into three groups (younger age group (YG), from 20 to 49 years; middle age group, from 50 to 69 years, and older age group (OG), of 70 years and above). Lumbar lordotic angle (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and the associations between the changes in LL (∆LL), SS (∆SS), PT (∆PT), and PI were analyzed. RESULTS: In the YG, the amount of change in LL, SS, and PT was larger than in the OG. These parameters correlated with age in the standing position but not in the sitting position. On the other hand, in all groups, there were positive correlations between PI and changes between the standing and sitting positions. Multiple logistic regression analysis demonstrated that ∆LL = 3.81 - 0.72 × PT + 0.52 × PI, ∆SS = - 4.50 - 5.3 × PT + 0.34 × PI, and ∆PT = - 9.1 + 3.5 × PT - 0.21 × PI. CONCLUSIONS: Change in lumbo-pelvic parameters between the sitting and standing positions correlated with PI. These slides can be retrieved under Electronic Supplementary Material.

Differences in cervical sagittal alignment between the standing and sitting positions.

BACKGROUND: Sagittal spinal alignment has mainly analyzed in the standing position. According to previous studies, there are significant differences in lumbopelvic alignment between the standing and sitting positions and cervical alignment is affected by lumbopelvic alignment. In this study, therefore, we hypothesized that cervical sagittal alignments are different between the standing and sitting positions. METHODS: A total of 108 patients with spinal degenerative diseases underwent whole spine radiography. Cervical lordosis (CL), C2-7 SVA, T1S, C7-S1 SVA, TK, LL, SS, PT, and PI were measured in the standing and sitting positions. Patients were classified into 3 groups according to the changes in CL (ΔCL, CL in the sitting position - CL in the standing position); ΔCL < -3° (Decreased group: DG; 28.7%), -3° ≤ ΔCL ≤ 3° (Unchanged group: UG; 41.7%), and ΔCL > 3° (Increased group: IG; 29.6%). RESULTS: The parameters of the UG in the standing position were closer to the ideal alignment (SRS-Schwab classification). In the DG, CL, T1S, and C7-S1 SVA in the standing position were significantly higher than in the UG. In the IG, PI-LL in the standing position was significantly higher than in the UG. In the sitting position, pelvis was rotated posteriorly (decrease in SS and increase in PT) and lumbar lordosis was flattened (decrease in LL) in all groups, and C2-7 SVA was significantly higher in the DG than in the UG. CONCLUSIONS: CL was different between the standing and sitting positions in 58.3% of individuals. However, patients with good spinal sagittal alignment appeared to not undergo any changes in cervical alignment. Our results suggest the possibility that patients who had a positive imbalance and large PI-LL mismatch in the standing position had decreased CL and increased CL, respectively, when in the sitting position.

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.

Limited efficacy of COX-2 inhibitors on nerve growth factor and metalloproteinases expressions in human synovial fibroblasts.

BACKGROUND: Nerve growth factor (NGF) is associated with arthritic pain and metalloproteinases are implicated in collagen and aggrecan degradation. Although selective COX-2 inhibitors are recommended for the treatment of arthritic diseases, their effects on NGF and metalloproteinases remain unclear. This study investigated the regulations of NGF and metalloproteinases by selective COX-2 inhibitors in isolated human synovial cells. METHODS: The isolated human synovial cells were stimulated with IL-1ß in the presence of selective COX-2 inhibitors (NS-398 or celecoxib) with or without exogenous PGE2 or its receptor (EP1-4) agonists. The expressions of NGF, MMP-1, -3, -13, ADAMTS-4, and -5 were quantified by real-time PCR and their proteins were determined by Western blotting. The amount of PGE2 released was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The IL-1ß inductions of NGF and MMP-1 and MMP-13 were augmented by the COX-2 inhibitors, whereas the inductions of ADAMTS-4 and ADAMTS-5 were inhibited. These actions were reversed by supplementing PGE2 or the EP4 agonist exogenously. CONCLUSION: Our comprehensive analysis revealed that COX-2 inhibitors may be beneficial for suppressing aggrecan degradation and for reducing inflammatory pain by inhibiting PGE2 release, although they may have limited efficacy in suppressing collagen degradation and nerve growth. This study suggests the feedback roles of PGE2 in the negative regulation of NGF and MMP-1 and MMP-13 and the positive regulation of ADAMTS-4 and ADAMTS-5.

Contrast-enhanced Magnetic Resonance Imaging in Patients With Dropped Head Syndrome.

STUDY DESIGN: This is a retrospective study of a consecutive case series of dropped head syndrome (DHS). OBJECTIVE: To identify the characteristic features of contrast-enhanced magnetic resonance imaging (MRI) in DHS patients. SUMMARY OF BACKGROUND DATA: Isolated neck extensor myopathy DHS is thought to be caused by severe cervical extensor muscle weakness from age-related loss of elasticity. However, the MRI findings of the cervical extensor muscles in DHS patients have not yet been characterized. MATERIALS AND METHODS: The subjects were 34 patients with isolated neck extensor myopathy DHS who underwent contrast-enhanced MRI within seven months after onset and 32 patients with age-matched cervical spondylosis or cervical soft-tissue tumor as controls. The presence of enhanced findings in the cervical extensor muscles, the involved cervical levels, and the characteristically enhanced shape of those muscles were evaluated using contrast-enhanced MRI. RESULTS: In the DHS group, the contrast-enhanced MRI showed pronounced enhancement at splenius capitis in 34 cases, rhomboid in 23 cases, semispinalis cervicis in seven cases, and levator scapulae in three cases. In the non-DHS group, none of those extensor muscles were enhanced. The enhanced pattern was butterfly shaped in 29 cases (85.3%) and linear in five cases (14.7%). All were located at the spinous process attachment at C6 or C7 in the DHS group. In the non-DHS group, seven cases presented an enhanced image of the spinous process, with C5-6 in one case, C6 in five cases, and C7 in one case. CONCLUSIONS: In DHS, contrast-enhanced MRI showed intramuscular enhancement of the cervical extensor muscles, which was not present in non-DHS cases. The enhanced muscles included the splenius capitis muscle in all cases. These findings may be useful for developing a strategy for DHS 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.

Long-term reoperation rates and causes for reoperations following lumbar microendoscopic discectomy and decompression: 10-year follow-up.

OBJECTIVE: To investigate the 10-year rates and causes of reoperations following lumbar microendoscopic discectomy for disc herniation (MEDH) and microendoscopic decompression for spinal stenosis (MEDS), as well as to define the reoperations at index and different lumbar levels. METHODS: Between June 2005 and May 2011, the same surgeon had been using MEDH and/or MEDS on 355 consecutive patients. The follow-up rate was 88.3%. The causes and rates of reoperations (RORs) were determined at 10 years after the initial operations. RESULTS: The 10-year reoperation rate for all patients combined was 22.1% (67/303). The 10-year reoperation rate for all cases that underwent repeat operations in the same segment was 16.5% (50/303); the most frequent reason for reoperation (FRR) was recurrence of disc herniation (ROR, 25/251 = 9.96%), the second FRR was an increase of postoperative spondylolisthesis and/or instability (ROR, 8/303 = 2.64%), and the third FRR was surgical site infection (ROR, 5/303 = 1.65%). Ten-year reoperation rate for all cases that underwent repeat operation at different lumbar levels was 5.61% (17/303); the most FRR was new disc herniation at another lumbar level (ROR, 10/303 = 3.30%), the second FRR was residual segmental stenosis (ROR, 4/303 = 1.32%), and the third FRR was new segmental stenosis at other lumbar levels (ROR, 2/303 = 0.66%). CONCLUSIONS: Three-fourths of all repeat operations were conducted in the same segment and one-fourth were performed at different lumbar levels. We believe that it is important to understand and prevent related problems.

Histopathological characteristics of cervical extensor tissue in patients with dropped head syndrome.

BACKGROUND: To date, the histopathologic characteristics of dropped head syndrome (DHS) have not been reported sufficiently. The present study investigates the histopathology of biopsy specimens from the cervical paravertebral region in patients with DHS. METHODS: Histopathological parameters were evaluated in biopsy specimens of the cervical paravertebral soft tissue from 15 patients with DHS. RESULTS: Among the 15 cases of DHS examined, skeletal muscle was identified in 7 cases, all of which showed necrosis, microvessel proliferation and atrophy. The ligament was identified in 12 cases, 8 of which showed degeneration. The lag time between the onset of symptoms and the performance of a biopsy in all 8 cases, which showed degeneration was over 3 months. Microvessel proliferation in the ligament was observed in 1 of the 4 cases, in which the lag time between the onset of symptoms and the performance of a biopsy was less than 3 months (acute or subacute phase), and in 7 of the 8 cases, in which the lag time between the symptoms and the performance of a biopsy was over 3 months (chronic phase). Chronic inflammation in the ligament was identified in 1 of the 12 cases. CONCLUSIONS: The identification of necrosis, microvessel proliferation, and atrophy in the skeletal muscle of patients with DHS and the presence of ligament degeneration and microvessel proliferation in the chronic but not acute or subacute phases may suggest that persistent skeletal muscle damage of the cervical paravertebral region causes subsequent ligament damage in patients with DHS.

Eight cases of sudden-onset dropped head syndrome: patient series.

BACKGROUND: As the proportion of elderly people continues to increase, the number of patients with dropped head syndrome (DHS) also grows. However, the relationship between onset and clinical course of DHS has hardly been studied, particularly, that of sudden-onset DHS has not been reported and remains unclear. OBSERVATIONS: Sudden-onset DHS was defined as presenting with chin on chest deformity within 3 days from the time of awareness of cervical weakness. Sixty-six patients with DHS visited our facility. Among them, 8 of the total cases (12.1%) had experienced sudden onset DHS (6 females and 2 males; average age: 71.9 ± 10.9 years). Six of 8 cases showed recovery by conservative treatment, whose first interventions were from 0.1 to 12 months, but 3 experienced recurrence. Diffuse spinal kyphotic-type DHS was seen in 2 cases, and both had recurring horizontal gaze disturbance after initial recovery. Two unimproved cases underwent surgery of combined anterior and posterior cervical fixation, and their first interventions were at 5 and 24 months. After surgery, cervical sagittal alignment was improved, and they could walk maintaining horizontal gaze. LESSONS: Sudden-onset DHS can be expected to have a better outcome, but recurrence is possible in global imbalanced-type DHS.

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.

Long-Term Outcomes Following Lumbar Microendoscopic Decompression for Lumbar Spinal Stenosis with and without Degenerative Spondylolisthesis: Minimum 10-Year Follow-Up.

OBJECTIVE: To determine whether preoperative presence of degenerative lumbar spondylolisthesis (DS) worsens the minimum 10-year outcome of patients undergoing microendoscopic decompression (MED) for lumbar spinal stenosis (SS). METHODS: Eighty patients undergoing MED were classified into 2 groups: DS group (34 SS with DS patients) and SS group (46 SS without DS patients). The degrees of improvement (DOIs) by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and intensities of improvement (IOIs) by Visual Analog Scale (VAS) at 120-159 (mean, 138.4) months after MED of the DS and SS groups were statistically compared. Patients with DS were classified into 2 groups based on the effectiveness by VAS or JOABPEQ: effective group (E group: IOI or DOI ≥20) and ineffective group (I group). All preoperative radiologic measurements were statistically compared between the E and I groups. RESULTS: Significant decreases in low back pain, leg pain, and numbness, as measured by VAS, were noted at follow-up in the DS and SS groups. The effectiveness rates of pain-related disorders, lumbar spine dysfunction, and gait disturbance by JOABPEQ were almost equally high in the DS and SS groups. Statistical comparisons of the DOIs in all 5 functional scores and IOIs in low back pain, leg pain, and numbness showed no significant differences between the DS and SS groups. No significant differences were confirmed between the E and I groups concerning preoperative spondylolisthesis and instability. CONCLUSIONS: Our study indicated that preoperative DS did not worsen the outcome of patients with SS undergoing MED.

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.