Clinicopathological and genomic features of superficial esophageal squamous cell carcinomas in nondrinker, nonsmoker females.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is sometimes detected in non-drinker and non-smoker females who are considered to have very low risk of ESCC development in daily practice. This study examined the clinicopathological and genomic characteristics of ESCCs in females with no history of drinking and smoking. METHODS: The sample comprised 118 ESCC lesions occurring in 95 female patients who underwent endoscopic submucosal dissection at our department between January 2008 and December 2019. The patients were categorized into two groups: 51 lesions in 49 patients with no history of drinking and smoking (nondrinker/nonsmoker [NDNS] group) and 69 lesions in 45 patients with a history of drinking or smoking (drinker/smoker [DS] group). We analyzed the differences in clinicopathological and cancerous genomic characteristics between the groups. Significant genomic alterations were validated using immunohistochemistry. RESULTS: Multiple logistic regression revealed that older age, fewer multiple Lugol-voiding lesions (LVLs), and reflux esophagitis (RE) were independently associated with the occurrence of ESCCs in the NDNS group. ESCC lesions in the NDNS group were predominantly located in the mid-thoracic esophagus, posterior wall side, with 0-IIa, the aspect ratio of the lesion >2 (vertical/horizontal), and endoscopic keratinization. Genetic analysis showed that CDKN2A driver alterations were significantly more frequent and KMT2D alterations were significantly less frequent in the NDNS group than in the DS group. KMT2D alterations were strongly correlated with immunostaining. CONCLUSION: Older nondrinker, nonsmoker females with RE and fewer multiple LVLs may develop longitudinal 0-IIa ESCC with keratinization of the posterior wall of the mid-thoracic esophagus. ESCCs in nondrinker, nonsmoker females had fewer KMT2D alterations and more CDKN2A alterations, which may be a biomarker for treatment.

Clinical factors associated with stable treatment of chronic constipation in Japanese patients.

BACKGROUND/AIMS: Chronic constipation (CC) is one of the most common gastrointestinal disorders in the general population. Although there are many treatment options, achieving a stable treatment for CC remains one of the challenges in clinical practice. This study aimed to evaluate the clinical factors associated with stable treatment for CC in Japanese patients. METHODS: A retrospective, cross-sectional, and multicenter study was carried out. Patients were eligible for inclusion if they fulfilled the Rome IV criteria for diagnosing CC and had been treated for at least one and a half years. Patients with up to two prescription modifications for CC in one year were defined as the stable treatment group, whereas those with three or more prescription changes were defined as the unstable treatment group. Univariate and multivariate analyses were carried out to identify factors associated with CC. RESULTS: A total of 114 patients have been recruited. There were 82 patients (77.0%) in the stable treatment group and 32 patients (23.0%) in the unstable treatment group. Based on multivariate likelihood analysis, only using acid-suppressive drugs contributed to stability treatment in CC patients (odds ratio: 2.81, 95% confidence interval: 1.12-7.08, p = 0.03). CONCLUSION: Administration of acid-suppressive drugs was the only factor related to the stability of CC treatment. Further studies are needed to validate the results as well as clarify the causes.

Predictive factors for esophageal stenosis in patients receiving prophylactic steroid therapy after endoscopic submucosal dissection for esophageal squamous cell carcinoma.

BACKGROUND: Methods to prevent esophageal stenosis (ES) after endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC) have received increasing attention. Although steroid administration is a prophylactic treatment, the risk factors for ES during prophylactic steroid therapy remain unknown. Therefore, this study aimed to retrospectively evaluate the risk factors for refractory ES in patients administered prophylactic steroids after ESD for ESCC. METHODS: Among 795 patients with ESCC (854 lesions), 180 patients (211 lesions) administered local triamcinolone acetonide (TrA) and/or oral prednisolone were recruited for this study. We compared the total number of endoscopic balloon dilatation (EBD) procedures performed for post-ESD ES and clinical findings (tumor size, ESD history or chemoradiation therapy [CRT], entire circumferential resection, muscle layer damage, supplemental oral prednisolone administration, EBD with TrA injection, and additional CRT) between patients with refractory and non-refractory ES. EBD was continued until dysphagia resolved. We categorized cases requiring ≥ 8 EBD procedures as refractory postoperative stenosis and divided the lesions into two groups. RESULTS: Multivariate logistic regression analysis revealed that factors such as ESD history, CRT history, tumor size, and entire circumferential resection were independently associated with the development of refractory ES. The withdrawal rates of EBD at 3 years were 96.1% (52/53) and 58.5% (39/59) in the non-refractory and refractory groups, respectively. CONCLUSIONS: Our data suggest that entire circumferential resection and CRT history are risk factors for refractory post-ESD ES in ESCC, even with prophylactic steroid administration.

Indications for Dental Floss Clip Traction During Gastric Endoscopic Submucosal Dissection by Less-Experienced Endoscopists.

PURPOSE: Dental floss clip (DFC) traction-assisted endoscopic submucosal dissection (ESD) is widely performed owing to its simplicity. This study aimed to clarify the appropriate indications for the DFC traction method in early gastric cancer when ESD is performed by less-experienced endoscopists. METHODS AND METHODS: We retrospectively analyzed 1,014 consecutive patients who had undergone gastric ESD performed by less-experienced endoscopists between January 2015 and December 2020. Gastric ESD was performed without DFC in all cases before December 2017 [DFC (-) group, 376 cases], and ESD was performed with DFC in all cases after January 2018 [DFC (+) group, 436 cases]. The procedure time and rates of en bloc resection, complete resection, and adverse events of the groups were compared. RESULTS: The procedure time did not differ significantly between the 2 groups. However, when comparing lesions >20 mm, the procedure time in the DFC (+) group was significantly shorter than that in the DFC (-) group (95±46 vs. 75±31, P<0.01). The procedure time for lesions located in the greater curvature of the upper or middle stomach and lesions >20 mm located in the lesser curvature side of the stomach in the DFC (+) group was significantly shorter than that in the DFC (-) group. CONCLUSIONS: The indications for DFC during gastric ESD by less-experienced endoscopists include lesions located in the greater curvature of the upper or middle stomach, and lesions >20 mm located in the lesser curvature of the stomach.

Comparison of the Degree of Expanded Spinal Canal Area between the Hinge-Side Area and the Open-Side Area in Cervical Open-Door Laminoplasty.

Background: There have been reports on the significant canal cross-sectional area (CSA) expansion difference between pre- and post-operation, but no comparison of CSA expansion between the hinge-side area (Area H) and the open-side area (Area O) has been reported. This study aimed to measure the spinal CSA expansion between Area H and Area O retrospectively after open-door laminoplasty using new titanium spacers and evaluated this common decompression procedure's effectiveness. Materials and Methods: This study included 27 patients diagnosed with cervical spondylotic radiculopathy or myelopathy, ossification of the posterior longitudinal ligament, and developmental canal stenosis from February 2021 to October 2022. The CSA difference between pre- and post-cervical laminoplasty (C4-C6 levels) was measured with cervical transverse computed tomography scan images. The CSA difference in Area H and Area O between pre- and post-laminoplasty was similarly calculated. Results: The spinal canal areas of each segment after open-door laminoplasty were significantly enlarged (P < 0.05). Area O was also significantly enlarged compared to that of Area H (P < 0.05). Conclusion: Area O was more enlarged than Area H, and both sides were statistically enlarged after open-door laminoplasty.

Endoscopic findings suggestive of a high risk of non-radical cure after definitive chemoradiotherapy for cT1bN0M0 esophageal squamous cell carcinoma.

BACKGROUND: Definitive chemoradiotherapy (DCRT) is a curative treatment option for cT1bN0M0 esophageal squamous cell carcinoma (ESCC); however, local residual disease and recurrence after complete remission may occur. We aimed to identify endoscopic findings associated with the risk of non-radical cure (local remnant or recurrence) after DCRT for cT1bN0M0 ESCC. METHODS: We retrospectively analyzed 40 consecutive patients with cT1bN0M0 ESCC who had undergone DCRT between January 2007 and December 2017. We examined the endoscopic findings in patients with residual or recurrent (RR) disease (RR group) and those without RR disease [non-RR (NRR) group] after DCRT. We also evaluated outcomes after DCRT for each endoscopic finding. RESULTS: There were 10 patients in the RR group and 30 patients in the NRR group. The RR group had a significantly larger tumor size and a higher proportion of lesions with type 0-I. The 5-year relapse-free survival rate was significantly lower in type 0-I and in the presence of B3 vessels. Endoscopic findings in 15 patients with cT1bN0M0 ESCC, type 0-I, who underwent DCRT revealed significantly more reddish lesions in the RR group compared to the NRR group. CONCLUSIONS: cT1bN0M0 ESCC large size, with B3 vessels, and type 0-I has a high risk of non-radical cure after DCRT, especially the reddish type 0-I, which may need to be considered for treatment similar to advanced cancer, including surgery with preoperative DCRT.

Risk Factors of Subsidence after Anterior Cervical Discectomy and Fusion with Double Cylindrical Cages for Cervical Degenerative Diseases: Minimum Two-year Follow-up Results.

Cylindrical cages were known to cause subsidence after anterior cervical discectomy and fusion (ACDF); hence, they were gradually replaced by box-shaped cages. However, this phenomenon has been inconclusive due to limited information and short-term results. Therefore, this study aimed to clarify risk factors for subsidence after ACDF using titanium double cylindrical cages with mid-term follow-up periods. This retrospective study included 49 patients (76 segments) diagnosed with cervical radiculopathy or myelopathy caused by disc herniation, spondylosis, and ossification of the posterior longitudinal ligament. These patients underwent ACDF using these cages from January 2016 to March 2020 in a single institution. Patient demographics and neurological outcomes were also examined. Subsidence was defined as a ≥3-mm segmental disc height decrease at the final follow-up lateral X-ray compared to that on the next day postoperatively. Subsidence occurred in 26 of 76 segments (34.7%) within the follow-up periods of approximately three years. Multivariate analysis using a logistic regression model demonstrated that multilevel surgery was significantly associated with subsidence. The majority of patients achieved good clinical outcomes based on the Odom criteria. This study demonstrated that multilevel surgery was the only risk factor of subsidence post-ACDF with double cylindrical cages. Despite the relatively high subsidence rates, the clinical outcome was almost good at least during the mid-term period.

Efficacy of the specialized scissor-type knife for gastric endoscopic submucosal dissection: a propensity score matched retrospective study.

Background and study aims Prevention of bleeding and perforation during gastric endoscopic submucosal dissection (ESD) is important. Scissor-type knives can accurately grasp and incise the targeted tissue using electrosurgical currents, thereby eliminating unexpected incisions. The SB Knife GX, a scissor-type knife specialized for gastric ESD, was released in June 2016 in Japan. The aim of the present study was to evaluate the efficacy and safety of gastric ESD using the SB Knife GX. Patients and methods A total of 716 patients who underwent gastric ESD at Hiroshima University Hospital between July 2016 and December 2020 were retrospectively reviewed. From these, 671 patients underwent ESD using the IT Knife 2 (IT-2 group), while 45 underwent ESD using an SB Knife GX (SB-GX group). After propensity score matching, the procedure time, specimen size, en bloc and complete resection rates, and intraoperative bleeding, delayed bleeding, and perforation rates were evaluated. Results No significant differences were observed in mean procedure time (SB-GX group: 115 ±â€Š165 min; IT-2 group: 95 ±â€Š61 min; P  = 0.82) and en bloc and complete resection rates between the two groups. Intraoperative bleeding rates were significantly lower in the SB-GX group than in the IT-2 group (18 % vs. 40 %; P  = 0.01), and there were no differences in delayed bleeding (4 % vs. 4 %) or perforation (0 % vs. 4 %) between the two groups. Conclusions The SB Knife GX was proven to be useful for control of intraoperative bleeding during gastric ESD, although the procedure time tended to be longer.

Safety and Validity of Anterior Cervical Disc Replacement for Single-level Cervical Disc Disease: Initial Two-year Follow-up of the Prospective Observational Post-marketing Surveillance Study for Japanese Patients.

Anterior cervical disc replacement (ACDR) using cervical artificial disc (CAD) has the advantage of maintaining the range of motion (ROM) at the surgical level, subsequently reducing the postoperative risk of adjacent disc disease. Following the approval for the clinical use in Japan, a post-marketing surveillance (PMS) study was conducted for two different types of CAD, namely, Mobi-C (metal-on-plastic design) and Prestige LP (metal-on-metal design). The objective of this prospective observational multicenter study was to analyze the first 2-year surgical results of the PMS study of 1-level ACDR in Japan. A total of 54 patients were registered (Mobi-C, n = 24, MC group; Prestige LP, n = 30, PLP group). Preoperative neurological assessment revealed radiculopathy in 31 patients (57.4%) and myelopathy in 15 patients (27.8%). Preoperative radiological assessment classified the disease category as disc herniation in 15 patients (27.8%), osteophyte in 6 patients (11.1%), and both in 33 patients (61.1%). The postoperative follow-up rates at 6 weeks, 6 months, 1 year, and 2 years after ACDR were 92.6%, 87.0%, 83.3%, and 79.6%, respectively. In both groups, patients' neurological condition improved significantly after surgery. Radiographic assessment revealed loss of mobility at the surgical level in 9.5% of patients in the MC group and in 9.1% of patients in the PLP group. No secondary surgeries at the initial surgical level and no serious adverse events were observed in either group. The present results suggest that 1-level ACDR is safe, although medium- to long-term follow-up is mandatory to further verify the validity of ACDR for Japanese patients.

Cervical Transverse Myelitis Following COVID-19 Vaccination.

Various COVID-19 vaccines are associated with numerous adverse side effects. Associations between vaccinations and neurological disorders, such as transverse myelitis, stroke, Bell's palsy, acute disseminated encephalomyelitis, and Guillain-Barré syndrome, have been reported. A 27-year-old Japanese woman presented with paresthesia four days after receiving a second dose of the COVID-19 vaccine. One month after vaccination, she started to feel left lower limb weakness, and her symptoms almost improved after two steroid pulse therapies. Spinal cord tumor biopsy could potentially help make a definitive diagnosis in clinical situations. However, it is very important to review the patient's medical history, including vaccinations received, before performing a direct spinal cord biopsy, which is invasive and does not guarantee a definitive diagnosis.

Cervical Extradural Arteriovenous Fistula without Intradural Drainage Successfully Treated with Endovascular Treatment Using Both Transvenous and Transarterial Approach: Case Report and Review of Literatures.

The classification of spinal extradural arteriovenous fistulas (AVFs) was reported based on a case series treated by microsurgery in 2009 and endovascular interventions in 2011. The present report describes a patient with extradural AVFs at the cervical spine manifesting gradual progressive radiculomyelopathy of bilateral upper extremities. Magnetic resonance imaging (MRI) revealed a mass sign from C1 to C4 at the right ventral side and the spinal cord was deviated to the left and indicated as a flow void sign. Diagnostic angiography revealed an extradural AVFs located at the C1-C4 level that was supplied by bilateral radicular artery from the vertebral artery (VA) and right ascending cervical artery (ACA). The shunting points were recognized multiply at C2/3 and C3/4 levels on the right. The transvenous embolization to the enlarged extradural venous plexus around the shunting points via right hypoglossal canal and the transarterial embolization against multi-feeders of the branch of left radicular artery, right ACA achieved complete occlusion of the lesions. His symptom was gradually recovered, and angiography performed 2 weeks after embolization showed no recurrence. When the arteriovenous shunts in the upper cervical spine were high flow shunts, transvenous approach via the hypoglossal canal might be one option for the treatment of spinal extradural AVFs.

Clinical outcome and radiological findings after cervical open door laminoplasty with titanium basket.

OBJECT: Cervical laminoplasty, which is well described in the Japanese literature, is the gold standard for decompressing multilevel spinal cord compression. Several spacers have been introduced to provide enough decompression of the spinal canal and reconstruct the stable posterior elements. The purpose of this study was to retrospectively evaluate radiological outcomes after open door laminoplasty using the titanium spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo). METHODS: Between July 2014 and June 2016, 31 patients with cervical spondylotic disease, including OPLL, were underwent open door laminoplasty with this device. All patients were clinically assessed by JOA score. The average follow-up period was 48.9 months with a range of 37-60 months. Postoperative radiological evaluation revealed bone union on both the open side and the gutter side from 12 months to 36 months after surgery on computed tomography. RESULTS: The clinical outcome improved from 10.9 points on the Japanese Orthopaedic Association scale to 15.8 points at 3 months after surgery and there were no significant major complications such as the implant failure. The bone union rate of the gutter side was 85.9% (85/99) at 1 year, 96.0% (95/99) at 3 years after surgery and of the open side was 57.6% (57/99) at 1 year, 89.9% (89/99) at 3 years after surgery. Circumferential fusion was confirmed 85.9% (85/99) of the time. CONCLUSION: This titanium spacer seemed to have the potential of promoting bone union between the spacer and both lamina, and lateral mass in cervical laminoplasty which is a safe procedure with satisfactory clinical results.

Efficacy of Atlantoaxial Transarticular Screw Fixation Using Navigation-Guided Drill: Technical Note.

BACKGROUND: Atlantoaxial transarticular screw fixation (TASF) is a procedure that involves inserting screws vertically into the articular processes of C1 and C2. However, this procedure is associated with a risk of injury to surrounding structures including the vertebral artery, carotid artery, pharynx, and spinal cord by misinserting K-wires or screws. This study was performed to evaluate the risk of TASF using 3-dimensional navigation-guided drilling and screw insertion tract creation. METHODS: Three patients underwent the surgical procedure using a navigation system guided by intraoperative computed tomography. The insertion tract of the screw was created using the navigation system to avoid penetration of the C1 anterior arch or damage to the vertebral artery. A blunt-tipped guide wire was used, which was safe to advance to the cortex of the anterior arch of C1. RESULTS: There were no complications or instrument failures in any of the surgeries. In each case, the total radiation dose delivered was 5.31-7.02 mGy, and total radiation exposure time was 55.6-106.8 seconds. Bone fusion was achieved in all cases. CONCLUSIONS: TASF using a navigation system for drilling is useful for accurate placement of K-wire and preventing damage of the vital structures, lowering the risk of the procedure.

Single - Door Cervical Laminoplasty Using Basket Laminoplasty Device: A Case Report.

BACKGROUND: The management of the cervical canal stenosis as a result of ossification of the posterior longitudinal ligament (OPLL) is still evolving. Anterior and posterior approaches are still much in demand by the surgeons. In Japan, a posterior approach is more well-known to be used as the case OPLL is often on the populace. Single-door laminoplasty technique or "Hirabayashi" often used with either autograft or allograft, with or without an additional miniplate. CASE PRESENTATION: In this case report, we would like to report the treatment of tetraparesis patients with "basket laminoplasty" using a special device with some advantages, not only providing stability of the lamina but also at the same time providing bone-graft container/basket for the benefit of the patient's bone fusion. CONCLUSION: Basket laminoplasty device is an excellent choice for cervical OPLL. We believe the use of this device is very favourable for long-term patient outcome.

In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty.

PURPOSE: To evaluate biomechanical differences between two surgical procedures for cervical open-door laminoplasty using human cadaveric spines. METHODS: Twenty-four cervical vertebrae (C4-C6) from eight fresh-frozen human cervical spines were subjected to mechanical testing after being instrumented for open-door laminoplasty using a newly designed plate-spacer device with a monocoque structure (plate-spacer group; n = 12) or by conventional miniplate-alone fixation (miniplate group; n = 12). Cantilever bending testing was performed by applying a compressive load in the cranio-caudal direction to the base of the spinous process of the reconstructed laminar arch constructs until failure and strength and stiffness of the laminar arch were determined. The results are presented as mean ± standard deviation. RESULTS: The plate-spacer group was approximately twice as strong as the miniplate group (27.6 ± 16.5 N vs. 13.5 ± 7.3 N, p < 0.05). Stiffness in the plate-spacer group exhibited the same trend (19.6 ± 9.3 N/mm vs. miniplate group: 11.4 ± 6.9 N/mm, p < 0.05). CONCLUSION: The fixation with the monocoque plate-spacer construct for open-door laminoplasty provided higher structural properties when compared against the plate-alone fixation. The spacer in the plate-spacer construct appears to contribute by preventing large deformations of the laminar arch caused by bending in cranio-caudal direction. Future studies will be required to investigate stress/strain distribution in the laminar arch constructs.

Limitations of median nerve somatosensory evoked potential monitoring during carotid endarterectomy.

OBJECTIVE: Hypoperfusion during carotid artery cross-clamping (CC) for carotid endarterectomy (CEA) may result in the major complication of perioperative stroke. Median nerve somatosensory evoked potential (MNSSEP) monitoring, which is an established method for the prediction of cerebral ischemia, has low sensitivity in detecting such hypoperfusion. In this study the authors sought to explore the limitations of MNSSEP monitoring compared to tibial nerve somatosensory evoked potential (TNSSEP) monitoring for the detection of CC-related hypoperfusion. METHODS: The authors retrospectively analyzed data from patients who underwent unilateral CEA with routine shunt use. All patients underwent preoperative magnetic resonance angiography and were monitored for intraoperative cerebral ischemia by using MNSSEP, TNSSEP, and carotid stump pressure during CC. First, the frequency of MNSSEP and TNSSEP changes during CC were analyzed. Subsequently, variables related to stump pressure were determined by using linear analysis and those related to each of the somatosensory evoked potential (SSEP) changes were determined by using logistic regression analysis. RESULTS: A total of 94 patients (mean age 74 years) were included in the study. TNSSEP identified a greater number of SSEP changes during CC than MNSSEP (20.2% vs 11.7%; p < 0.05). Linear regression analysis demonstrated that hypoplasia of the contralateral proximal segment of the anterior cerebral artery (A1 hypoplasia) (p < 0.01) and hypoplasia of the ipsilateral precommunicating segment of the posterior cerebral artery (P1 hypoplasia) (p = 0.02) independently and negatively correlated with stump pressure. Both contralateral A1 hypoplasia (OR 26.25, 95% CI 4.52-152.51) and ipsilateral P1 hypoplasia (OR 8.75, 95% CI 1.83-41.94) were independently related to the TNSSEP changes. However, only ipsilateral P1 hypoplasia (OR 8.76, 95% CI 1.61-47.67) was independently related to MNSSEP changes. CONCLUSIONS: TNSSEP monitoring appears to be superior to MNSSEP in detecting CC-related hypoperfusion. Correlation with stump pressure and SSEP changes indicates that TNSSEP, and not MNSSEP monitoring, is a reliable indicator of cerebral ischemia in the territory of the anterior cerebral artery.

Delayed Postoperative Spinal Epidural Hematoma after Cervical Laminoplasty.

A 56-year-old man underwent cervical laminoplasty for cervical spondylosis. On the 7th postoperative day, he suddenly felt severe neck pain, and tetraplegia developed rapidly over 1.5 hrs. Computed tomography demonstrated a huge hematoma compressing the cervical spinal cord. Clot was evacuated 3 hrs after the onset of symptoms. The patient's postoperative course was uneventful. His blood pressure could not be properly controlled in the perioperative period. Surgeons should keep in mind that delayed postoperative spinal epidural hematoma (DPSEH) can occur more than a week after surgery, and meticulous blood pressure control is important for more than a week after a spinal operation.

Radiologic Evaluation of Ossification of the Posterior Longitudinal Ligament with Dural Ossification.

There are 3 basic radiological patterns of dural ossification (DO). Although double-layer DO is most common, when examining neuroimaging of ossification of the posterior longitudinal ligament (OPLL), isolated DO or masse DO should be kept in mind. Bone window computed tomography (CT) is most sufficient in identifying any type of DO associated with OPLL. Sagittal reformation of CT has replaced polytomography. MRI is not optimal for identification of DO and OPLL. Surgical approaches should be determined based on this important radiological information to avoid an unexpected complication. Expansive laminoplasty is the procedure of choice when DO is predominant.

History and Evolution of Laminoplasty.

Techniques of expansive laminoplasty for degenerative cervical myelopathy and ossified posterior longitudinal ligament are described, focusing on the history of the surgical procedure. Laminectomy was the only approach for posterior decompression before Japanese orthopedic surgeons introduced laminoplasty from the 1970s to the 1980s to overcome the poor outcomes of laminectomy. Recent laminoplasty techniques offer less invasive maneuvers to the posterior cervical muscle structures to reduce axial neck pain and to obtain better functional outcome, but every operation is carried out based on the unchanged initial concept. Some recent attempts to improve the surgical results are also discussed.

Clinical Characteristics and Management of C3-4 Degenerative Cervical Myelopathy.

Single-level anterior cervical discectomy and fusion (ACDF) was performed at C3-4; non-C3-4 ACDF patients of the authors' random sample of ACDF patients were compared with C3-4 ACDF patients. The radiological study of C3-4 ACDF patients shows that they had significant cervical lordosis, and cervical motion was dependent on the C3-4 segment, which accounted for 39.8% of C2-7 range of intervertebral motion (total motion). In C3-4 ACDF patients, not only static factors but also dynamic factors (instability) at the C3-4 level contributed to the major causes of degenerative cervical myelopathy.