Effect of Stent Placement on Survival in Patients with Malignant Portal Vein Stenosis:A Propensity Score–Matched Study

Objective@#Percutaneous portal vein (PV) stent placement can be an effective treatment for symptoms associated with portal hypertension. This study aimed to evaluate the effect of PV stenting on the overall survival (OS) in patients with malignant PV stenosis. @*Materials and Methods@#Two groups of patients with malignant PV stenosis were compared in this retrospective study involving two institutions. A total of 197 patients who underwent PV stenting between November 2016 and August 2019 were established as the stent group, whereas 29 patients with PV stenosis who were treated conservatively between July 2013 and October 2016 constituted the no-stent group. OS was compared between the two groups before and after propensity score matching (PSM). Risk factors associated with OS were evaluated using the Cox proportional hazards model. Procedureassociated adverse events were also evaluated. @*Results@#The stent group finally included 100 patients (median age, 65 [interquartile range, 58–71] years; 64 male). The nostent group included 22 patients (69 [61–75] years, 13 male). Stent placement was successful in 95% of attempted cases, and the 1- and 2-year stent occlusion–free survival rate was 56% (95% confidence interval, 45%–69%) and 44% (32%–60%), respectively. The median stent occlusion–free survival time was 176 (interquartile range, 70–440) days. OS was significantly longer in the stent group than in the no-stent group (median 294 vs. 87 days, p < 0.001 before PSM, p = 0.011 after PSM).The 1- and 3-year OS rates before PSM were 40% and 11%, respectively, in the stent group. The 1-year OS rate after PSM was 32% and 5% in the stent and no-stent groups, respectively. Anemia requiring transfusion (n = 2) and acute thrombosis necessitating re-stenting (n = 1) occurred in three patients in the stent group within 1 week. @*Conclusion@#Percutaneous placement of a PV stent may be effective in improving OS in patients with malignant PV stenosis.

Conflicts of Interest in Research and Clinical Practice

Recently, doctors and researchers are establishing relationships with interested parties from companies, research institutes, health care institutions, and academic journals, instead of conducting independent medical care or research work. They may have multiple interests as an advisor or a shareholder in the relevant company. Such a situation can foster a conflict of interest when their interests influence one’s decision or judgment. Conflict of interest is an extremely important issue because it can infringe the integrity of research, endanger subjects or patients, pose a risk to the public, and deteriorate public perception of science. This brief review explores the definition, examples, and solutions to conflict of interest.

Comparison of Radiological Tumor Response Based on iRECIST and RECIST 1.1 in Metastatic Clear-Cell Renal Cell Carcinoma Patients Treated with Programmed Cell Death-1 Inhibitor Therapy

Objective@#To evaluate the radiological tumor response patterns and compare the response assessments based on immunebased therapeutics Response Evaluation Criteria in Solid Tumors (iRECIST) and RECIST 1.1 in metastatic clear-cell renal cell carcinoma (mccRCC) patients treated with programmed cell death-1 (PD-1) inhibitors. @*Materials and Methods@#All mccRCC patients treated with PD-1 inhibitors at Henan Cancer Hospital, China, between January 2018 and April 2019, were retrospectively studied. A total of 30 mccRCC patients (20 males and 10 females; mean age, 55.6 years; age range, 37–79 years) were analyzed. The target lesions were quantified on consecutive CT scans during therapy using iRECIST and RECIST 1.1. The tumor growth rate was calculated before and after therapy initiation. The response patterns were analyzed, and the differences in tumor response assessments of the two criteria were compared. The intra- and inter-observer variabilities of iRECIST and RECIST 1.1 were also analyzed. @*Results@#The objective response rate throughout therapy was 50% (95% confidence interval [CI]: 32.1–67.9) based on iRECIST and 30% (95% CI: 13.6–46.4) based on RECIST 1.1. The time-to-progression (TTP) based on iRECIST was longer than that based on RECIST 1.1 (median TTP: not reached vs. 170 days, p = 0.04). iRECIST and RECIST 1.1 were discordant in 8 cases, which were evaluated as immune-unconfirmed PD based on iRECIST and PD based on RECIST 1.1. Six patients (20%, 6/30) had pseudoprogression based on iRECIST, of which four demonstrated early pseudoprogression and two had delayed pseudoprogression.Significant differences in the tumor response assessments based on the two criteria were observed (p < 0.001). No patients demonstrated hyperprogression during the study period. @*Conclusion@#Our study confirmed that the iRECIST criteria are more capable of capturing immune-related atypical responses during immunotherapy, whereas conventional RECIST 1.1 may underestimate the benefit of PD-1 inhibitors. Pseudoprogression is not rare in mccRCC patients during PD-1 inhibitor therapy, and it may last for more than the recommended maximum of 8 weeks, indicating a limitation of the current strategy for immune response monitoring.

Update on Transradial Access for Percutaneous Transcatheter Visceral Artery Embolization

Transfemoral access (TFA) is a widely used first-line approach for most peripheral vascular interventions. Since its introduction in cardiologic and neurointerventional procedures, several advantages of transradial access (TRA) over TFA have been demonstrated, such as patient preference, lower complication rates, early ambulation, and shorter hospital stay. However, studies reporting the safety and efficacy of this approach for peripheral vascular interventions performed by interventional radiologists are relatively few. This review aimed to summarize the technique and clinical applications of TRA in percutaneous transcatheter visceral artery embolization and the management of complications.

A Canine Model for Lymphangiography and Thoracic Duct Access

OBJECTIVE: To evaluate the technical feasibility of intranodal lymphangiography and thoracic duct (TD) access in a canine model.MATERIALS AND METHODS: Five male mongrel dogs were studied. The dog was placed in the supine position, and the most prominent lymph node in the groin was accessed using a 26-gauge spinal needle under ultrasonography (US) guidance. If the cisterna chyli (CC) was not opacified by bilateral lymphangiography, the medial iliac lymph nodes were directly punctured and Lipiodol was injected. After opacification, the CC was directly punctured with a 22-gauge needle. A 0.018-in microguidewire was advanced through the CC and TD. A 4-Fr introducer and dilator were then advanced over the wire. The microguidewire was changed to a 0.035-in guidewire, and this was advanced into the left subclavian vein through the terminal valve of the TD. Retrograde TD access was performed using a snare kit.RESULTS: US-guided lymphangiography (including intranodal injection of Lipiodol [Guerbet]) was successful in all five dogs. However, in three of the five dogs (60%), the medial iliac lymph nodes were not fully opacified due to overt Lipiodol extravasation at the initial injection site. In these dogs, contralateral superficial inguinal intranodal injection was performed. However, two of these three dogs subsequently underwent direct medial iliac lymph node puncture under fluoroscopy guidance to deliver additional Lipiodol into the lymphatic system. Transabdominal CC puncture and cannulation with a 4-Fr introducer was successful in all five dogs. Transvenous retrograde catheterization of the TD (performed using a snare kit) was also successful in all five dogs.CONCLUSION: A canine model may be appropriate for intranodal lymphangiography and TD access. Most lymphatic intervention techniques can be performed in a canine using the same instruments that are employed in a clinical setting.

Paclitaxel-Coated Balloon versus Plain Balloon Angioplasty for Dysfunctional Autogenous Radiocephalic Arteriovenous Fistulas: A Prospective Randomized Controlled Trial

Objective@#To report the mid-term results of a single-center randomized controlled trial comparing drug-coated balloon angioplasty (DBA) and plain balloon angioplasty (PBA) for the treatment of dysfunctional radiocephalic arteriovenous fistulas (RCAVFs). @*Materials and Methods@#In this prospective study, 39 patients (mean age, 62.2 years; 21 males, 18 females) with RCAVFs failing due to juxta-anastomotic stenosis were randomly assigned to undergo either both DBA and PBA (n = 20, DBA group) or PBA alone (n = 19, PBA group) between June 2016 and June 2018. Primary endpoints were technical and clinical success and target lesion primary patency (TLPP); secondary outcomes were target lesion secondary patency (TLSP) and complication rates.Statistical analysis was performed using the Kaplan-Meier product limit estimator. @*Results@#Demographic data and baseline clinical characteristics were comparable between the groups. Technical and clinical success rates were 100% in both groups. There was no significant difference between the groups in the mean duration of TLPP (DBA group: 26.7 ± 3.6 months; PBA group: 27.0 ± 3.8 months; p = 0.902) and TLSP (DBA group: 37.3 ± 2.6 months; PBA group: 40.4 ± 1.5 months; p = 0.585). No procedural or post-procedural complications were identified. @*Conclusion@#Paclitaxel-coated balloon use did not significantly improve TLPP or TLSP in the treatment of juxta-anastomotic stenosis of dysfunctional RCAVFs.

Percutaneous Thrombin Injection for the Treatment of Post-Procedural Iatrogenic Pseudoaneurysms

PURPOSE@#To report our clinical experience of thrombin injection for iatrogenic pseudoaneurysms of peripheral arteries with or without balloon dilatation and coil embolization as adjunctive techniques.@*MATERIALS AND METHODS@#A total of 10 patients undergoing thrombin injection for iatrogenic pseudoaneurysms from September 2007 to June 2017 were retrospectively investigated. The causative procedures, location of pseudoaneurysms, and complications were recorded, and technical and clinical success rates of the treatment were assessed.@*RESULTS@#The femoral and brachial arteries were treated in eight and two patients, respectively. Technical success was confirmed in all cases, and a clinical success rate was 70% (7/10) was noted. Two patients presented with a complication of acute thrombosis at the distal arteries. In 7 patients, balloon occlusion was performed before injection of thrombin to prevent the spread of thrombin. Coil embolization of the distal branch was also performed in one of these patients.@*CONCLUSION@#For pseudoaneurysms of the femoral and brachial arteries that develop after various vascular procedures, thrombin injection is a safe and efficient treatment choice. In some cases, where there is concern for thrombin leakage, balloon occlusion and coil embolization could be performed together.

Recent Advances in Ureteral Stents

A ureteral stent is widely used to drain ureteral obstructions, which allows urine to bypass the obstruction. The double J stent, a representative ureteral stent, has undergone many advancements in material and design recently. In addition, indications of double J stent insertion have been broadly expanded to improve urinary obstruction before and after extracorporeal shock wave lithotripsy and to maintain ureteral patency after a ureteral surgery or treatment of a ureteral fistula. The recently developed metallic ureteral stents showed excellent long-term patency in patients with malignant ureteral strictures. Therefore, metallic stents could be an alternative to double J stents in select patients. In this review article, we describe the materials, designs, indications, details of the antegrade ureteral stenting procedure, and outcomes of the double J stent and metallic stent procedures.

Update on Transarterial Chemoembolization with Drug-Eluting Microspheres for Hepatocellular Carcinoma

Conventional transcatheter arterial chemoembolization (c-TACE) is a widely used first-line palliative treatment for patients with unresectable hepatocellular carcinoma (HCC). Despite the effectiveness of c-TACE, to date, technique and procedure scheduling has not yet been standardized. Drug-eluting microspheres (DEMs) were therefore introduced to ensure more sustained and tumor-selective drug delivery for permanent embolization. These DEMs can load various drugs and release them in a sustained manner over a prolonged period. This approach ensures the delivery of high concentrations of chemotherapeutic agents to tumors, without increasing systemic concentrations, and promote tumor ischemia and necrosis. This review summarizes the recent advances in the use of DEM-TACE to treat HCC.

Recent Update of Embolization of Postpartum Hemorrhage

Postpartum hemorrhage (PPH) is a life-threatening condition and remains a leading cause of maternal mortality. Transcatheter arterial embolization (TAE) is an effective therapeutic strategy for PPH with the advantages of fast speed, repeatability, and the possibility of fertility preservation. We reviewed the vascular anatomy relevant to PPH, the practical details of TAE emphasizing the timing of embolization, and various clinical conditions of PPH according to a recent literature review.

Percutaneous Metallic Stent Placement for Palliative Management of Malignant Biliary Hilar Obstruction

OBJECTIVE: To investigate the outcomes of percutaneous metallic stent placements in patients with malignant biliary hilar obstruction (MBHO). MATERIALS AND METHODS: From January 2007 to December 2014, 415 patients (mean age, 65 years; 261 men [62.8%]) with MBHO were retrospectively studied. All the patients underwent unilateral or bilateral stenting in a T, Y, or crisscross configuration utilizing covered or uncovered stents. The clinical outcomes evaluated were technical and clinical success, complications, overall survival rates, and stent occlusion-free survival. RESULTS: A total of 784 stents were successfully placed in 415 patients. Fifty-five patients had complications. These complications included hemobilia (n = 19), cholangitis (n = 13), cholecystitis (n = 11), bilomas (n = 10), peritonitis (n = 1), and hepatic vein-biliary fistula (n = 1). Clinical success was achieved in 370 patients (89.1%). Ninety-seven patients were lost to follow-up. Stent dysfunction due to tumor ingrowth (n = 107), sludge incrustation (n = 44), and other causes (n = 3) occurred in 154 of 318 patients. The median overall survival and the stent occlusion-free survival were 212 days (95% confidence interval [CI], 186−237 days) and 141 days (95% CI, 126−156 days), respectively. The stent type and its configuration did not affect technical success, complications, successful internal drainage, overall survival, or stent occlusion-free survival. CONCLUSION: Percutaneous stent placement may be safe and effective for internal drainage in patients with MBHO. Furthermore, stent type and configuration may not significantly affect clinical outcomes.

A Prospective Randomized Comparison of a Covered Metallic Ureteral Stent and a Double-J Stent for Malignant Ureteral Obstruction

OBJECTIVE: To compare the safety and efficacy between a covered metallic ureteral stent (CMS) and a double-J ureteral stent (DJS) for the treatment of a malignant ureteral obstruction (MUO). MATERIALS AND METHODS: Nineteen patients (seven men and 12 women; mean age, 53.4 years) were randomly assigned to the CMS (n = 10) or DJS (n = 9) group. The following were compared between the two groups: technical success, i.e., successful stent placement into desired locations; stent malfunction; stent patency, i.e., no obstruction and no additional intervention; complications; and patient survival. RESULTS: The technical success rate was 100% in all 10 and 12 ureteral units in the CMS and DJS groups, respectively. During the mean follow-up period of 253.9 days (range, 63–655 days), stent malfunction was observed in 40.0% (4/10) and 66.7% (8/12) in the CMS and DJS groups, respectively. In the per-ureteral analysis, the median patency time was 239.0 days and 80.0 days in the CMS and DJS groups, respectively. The CMS group yielded higher patency rates compared with the DJS group at three months (90% vs. 35%) and at six months (57% vs. 21%). The overall patency rates were significantly higher in the CMS group (p = 0.041). Complications included the migration of two metallic stents in one patient in the CMS group, which were removed in a retrograde manner. The two patient groups did not differ significantly regarding their overall survival rates (p = 0.286). CONCLUSION: Covered metallic ureteral stent may be effective for MUO.

Endovascular treatment of pancreatitis-related gastrointestinal bleeding

Hemorrhage following pancreatitis may become complicated during the disease course and with possibly fatal consequences. Radiologic findings are as follows: the presence of hematomas, hemorrhagic pseudocysts, extravasation of contrast media or the formation of arterial pseudoaneurysms. The digital subtraction angiography findings are as follows: contrast extravasation due to arterial rupture; pseudoaneurysm formation; and luminal irregularity. A pseudoaneurysm is considered to be treated as soon as detected due to its risk of rupture. Endovascular management, which includes embolization using coils, N-butyl cyanoacrylate, gelatin sponge, stents, and thrombin, is an effective option for the treatment for pancreatitis-related bleeding.

Ultrasound-Guided Intraoperative Radiofrequency Ablation and Surgical Resection for Liver Metastasis from Malignant Gastrointestinal Stromal Tumors

OBJECTIVE: To evaluate the effectiveness, safety, and feasibility of intraoperative radiofrequency ablation (IORFA) under ultrasound guidance for the treatment of liver metastases from gastrointestinal stromal tumors (GISTs). MATERIALS AND METHODS: From August 2009 to February 2017, 24 patients with liver metastases of GISTs underwent IORFA, 14 underwent concurrent IORFA and primary GIST resection, and 10 underwent IORFA to treat hepatic recurrence after previous primary GIST resection. Seventy-six hepatic metastases were treated, of which 47 were surgically resected and 29 underwent IORFA. All included patients received imatinib therapy as standard treatment before and after IORFA or surgical resection. A retrospective medical record review was conducted, and follow-up data were collected. Technical success and effectiveness, overall and GIST-specific survival, and complications were assessed. RESULTS: The mean follow-up duration was 50.7 ± 34.7 months. The technical success rate of IORFA was 100%. New metastases developed in three of the 24 patients (12.5%) following a complete response 16, 51, and 95 months after IORFA, respectively. The cumulative one-, three-, and five-year overall survival rates were 100, 94.4, and 87.7%, respectively. The one-, three-, and five-year GIST-related survival rates were 100, 94.4, and 94.4%, respectively. Two major complications (biliary stricture and hepatic abscess) were observed. CONCLUSION: IORFA appears to be a feasible and safe treatment option for liver metastasis in patients with primary GISTs. In addition, IORFA and surgical resection may be complementary, helping to obtain complete response in cases of otherwise inoperable liver metastases secondary to GISTs.

Postoperative Chylothorax: the Use of Dynamic Magnetic Resonance Lymphangiography and Thoracic Duct Embolization

Dynamic enhanced magnetic resonance lymphangiography can be used to provide anatomic and dynamic information for various lymphatic diseases, including thoracic duct injury, and can also help to guide the thoracic duct embolization procedure. We present a case of postoperative chylothorax demonstrated by dynamic enhanced MR lymphangiography. In this case, the chyle leakage site and location of cisterna chyli were clearly visualized by dynamic enhanced MR lymphangiography, thus allowing for management with thoracic duct embolization.

Intraductal migration of necrotic hepatocellular carcinoma: A possible cause of obstructive cholangitis after chemoembolization

Acute obstructive cholangitis due to the migration of necrotized tumor fragment(s) has been rarely reported after transarterial chemoembolization (TACE). We report an unusual case of it, which was demonstrated by computed tomography (CT) and endoscopic retrograde cholangiography. We suggest that in the setting of acute biliary obstruction after TACE with a CT-demonstrated new intraductal soft tissue lesion with or without a radiopaque portion, along with no or less visualization of a previous tumor located inside or near the duct, the possibility of intraductal migration of a necrotic tumor fragment should be considered. Both clinicians and radiologists should become familiar with this condition because it may be ignored or misinterpreted as biliary calculi.

Clinical Outcomes of Angiography and Transcatheter Arterial Embolization for Acute Gastrointestinal Bleeding: Analyses according to Bleeding Sites and Embolization Types / 대한소화기학회지

BACKGROUND/AIMS: The clinical outcomes of angiography and transcatheter arterial embolization (TAE) for acute gastrointestinal bleeding (GIB) have not been completely assessed, especially according to bleeding sites. This study aimed to assess the efficacy of angiography and safety of TAE in acute GIB. METHODS: This was a retrospective study evaluating the records of 321 patients with acute GIB who underwent angiography with or without TAE. Targeted TAE was conducted in 134 patients, in whom angiography showed bleeding sources. Prophylactic TAE was performed in 29 patients when the bleeding source was not detected but a specific vessel was strongly suspected by other examinations. The rate of technical success, clinical success, and complications were analyzed. RESULTS: The detection rate of bleeding source via angiography was 50.8% (163/321), which was not different according to the bleeding sites. The detection rate was higher if the probable bleeding source had already been found by another investigation (59.7% vs. 35.8%, p<0.001). TAE sites were upper GIB in 67, mid GIB in 74, and lower GIB in 22. The technical success rate was 99.3% (133/134), and the clinical success rate was 63.0% (104/163). The prophylactic embolization group showed lower clinical success rate than the targeted embolization group (44.8% vs. 67.9%, p=0.06). The TAE-related complication rate was 12.9% (21/163). Ischemia and/or infarction was more common after TAE for mid and lower GIB than for upper GIB (15.6% vs. 3.0%, p=0.007). CONCLUSIONS: Angiography with or without TAE was an effective method for acute GIB. Targeted embolization should be performed if possible given that it has a higher clinical success rate.

Efficacy of Prophylactic Uterine Artery Embolization before Obstetrical Procedures with High Risk for Massive Bleeding

OBJECTIVE: To evaluate the safety and efficacy of prophylactic uterine artery embolization (UAE) before obstetrical procedures with high risk for massive bleeding. MATERIALS AND METHODS: A retrospective review of 29 female patients who underwent prophylactic UAE from June 2009 to February 2014 was performed. Indications for prophylactic UAE were as follows: dilatation and curettage (D&C) associated with ectopic pregnancy (cesarean scar pregnancy, n = 9; cervical pregnancy, n = 6), termination of pregnancy with abnormal placentation (placenta previa, n = 8), D&C for retained placenta with vascularity (n = 5), and D&C for suspected gestational trophoblastic disease (n = 1). Their medical records were reviewed to evaluate the safety and efficacy of UAE. RESULTS: All women received successful bilateral prophylactic UAE followed by D&C with preservation of the uterus. In all patients, UAE followed by obstetrical procedure prevented significant vaginal bleeding on gynecologic examination. There was no major complication related to UAE. Vaginal spotting continued for 3 months in three cases. Although oligomenorrhea continued for six months in one patient, normal menstruation resumed in all patients afterwards. During follow-up, four had subsequent successful natural pregnancies. Spontaneous abortion occurred in one of them during the first trimester. CONCLUSION: Prophylactic UAE before an obstetrical procedure in patients with high risk of bleeding or symptomatic bleeding may be a safe and effective way to manage or prevent serious bleeding, especially for women who wish to preserve their fertility.

Shear wave elastography using ultrasound: effects of anisotropy and stretch stress on a tissue phantom and in vivo reactive lymph nodes in the neck

PURPOSE: The purpose of this study was to evaluate how the anisotropy and the static stretch stress of the cervical musculature influence the measured shear modulus in a tissue-mimicking phantom and in cervical lymph nodes in vivo by using shear wave elastography (SWE). METHODS: SWE was performed on a phantom using a pig muscle and on the middle jugular cervical lymph nodes in six volunteers. Tissue elasticity was quantified using the shear modulus and a supersonic shear wave imaging technique. For the phantom study, first, the optimal depth for measurement was determined, and then, SWE was performed in parallel and perpendicular to the muscle fiber orientation with and without strain stress. For the in vivo study, SWE was performed on the cervical lymph nodes in parallel and perpendicular to the sternocleidomastoid muscle fiber direction with and without neck stretching. The mean values of the shear modulus (meanSM) were then analyzed. RESULTS: In the phantom study, the measured depth significantly influenced the meanSM with a sharp decrease at the depth of 1.5 cm (P<0.001). Strain stress increased the meanSM, irrespective of the muscle fiber orientation (P<0.001). In the in vivo study, the meanSM values obtained in parallel to the muscle fiber orientation were greater than those obtained perpendicular to the fiber orientation, irrespective of the stretch stress (P<0.001). However, meanSM was affected significantly by the stretch stress parallel to the muscle fiber orientation (P<0.001). CONCLUSION: The anisotropic nature of the cervical musculature and the applied stretch stress explain the variability of the SWE measurements and should be identified before applying SWE for the interpretation of the measured shear modulus values.

A Sternum-Disk Distance Method to Identify the Skin Level for Approaching a Surgical Segment without Fluoroscopy Guidance during Anterior Cervical Discectomy And Fusion

STUDY DESIGN: A retrospective review of prospectively collected data. PURPOSE: To introduce the sternum-disk distance (SDD) method for approaching the exact surgical level without C-arm guidance during anterior cervical discectomy and fusion (ACDF) surgery and to evaluate its accuracy and reliability. OVERVIEW OF LITERATURE: Although spine surgeons have tried to optimize methods for identifying the skin level for accessing the operative disk level without C-arm guidance during ACDF, success has rarely been reported. METHODS: In total, 103 patients who underwent single-level ACDF surgery with the SDD method were enrolled. The primary outcome measure was the accuracy of the SDD method. The secondary outcome measures were the mean SDD value at each cervical level from the cranial margin of the sternum in the neutral and extension positions of the cervical spine and the inter- and intra-observer reliability of the SDD outcome determined using repeated measurements by three orthopedic spine surgeons. RESULTS: The SDD accuracy (primary outcome measure) was indicated in 99% of the patients (102/103). The mean SDD values in the neutral-position magnetic resonance imaging (MRI) were 108.8 mm at C3–C4, 85.3 mm at C4–C5, 64.4 mm at C5–C6, 44.3 mm at C6–C7, and 24.1 mm at C7–T1; and those in the extension-position MRI were 112.9 mm at C3–C4, 88.7 mm at C4–C5, 67.3 mm at C5–C6, 46.5 mm at C6–C7, and 24.3 mm at C7–T1. The Cohen kappa coefficient value for intra-observer reliability was 0.88 (excellent reliability), and the Fleiss kappa coefficient value for inter-observer reliability as reported by three surgeons was 0.89 (excellent reliability). CONCLUSIONS: Based on the results of the present study, we recommend performing ACDF surgery using the SDD method to determine the skin level for approaching the surgical cervical segment without fluoroscopic guidance.