Risk Factors for Early- and Late-Onset Cholecystitis after Y-Configured Metal Stent Placement in Patients with Malignant Hilar Biliary Obstruction: A Single-Center Study.

This study evaluated the prevalence and risk factors of early- (within 7 days of placement) and late-onset (after 7 days of placement) cholecystitis after Y-configured metal stent placement. Between June 2005 and August 2020, 109 patients who had been treated with Y-configured metal stents for malignant hilar obstruction were enrolled in the study. We retrospectively analyzed the potential risk factors for post-stent cholecystitis. The presence of diabetes (p = 0.042), the length of the common part of the Y-stent (p = 0.017), filling of the gallbladder with contrast medium during the procedure (p = 0.040), and tumor invasion of the cystic duct accompanied by filling the gallbladder with contrast medium during metal stent placement (p = 0.001) were identified as important risk factors. In cases of late-onset cholecystitis, stent obstruction (p = 0.004) and repeated endoscopic procedures due to stent malfunction (p = 0.024) were significant risk factors. In the multivariate logistic regression analysis, significant risk factors were the length of the common part of the Y-stent (p = 0.032) in early-onset cholecystitis and stent obstruction (p = 0.007) in late-onset cholecystitis. This study demonstrated that early-onset cholecystitis may occur in patients according to the length of the common portion of the Y-stent. In contrast, late-onset cholecystitis may occur in patients with stent obstruction.

A novel encountered-type master device with precise manipulation for robot-assisted microsurgery.

BACKGROUND: The unconstrained master devices have emerged as attractive alternatives to the existing linkage-based counterparts. However, the conventional unconstrained master device's manipulation methods have several disadvantages in efficiency and precision. METHODS: We propose an encountered-type master device based on an electromagnetic tracking solution with a prismatic joint at the tip, capable of continuous spatial manipulation with the tip supported on the surface. We performed path-following task and pointing tasks to analyze the performance of the master device. RESULTS: The most convenient, efficient, accurate positioning and precise pointing were possible with a closed loop support condition. Moreover, the tasks under this condition were also completed with higher accuracy, and precision when applying lower motion scale factors. CONCLUSIONS: The proposed master device allowed precise and accurate manipulation for microsurgical tasks. Compared with the conventional unconstrained master devices, the proposed master device provides the ability to perform precise work with a clutching-free motion.

Efficacy of Zero-Profile Implant in Anterior Fusion to Treat Degenerative Cervical Spine Disease: Comparison with Techniques Using Bone Graft and Anterior Plating.

BACKGROUND: The efficacy of anterior fusion using zero-profile implant (Zero-P) in the surgical treatment of degenerative cervical disease was investigated through radiographic and clinical comparisons with existing treatments using autograft or allograft and anterior plating. MATERIAL AND METHODS: A total of 130 patients who underwent anterior decompression and fusion for degenerative cervical spine disease with a follow-up of at least 1 year were analyzed retrospectively. The cases were divided into three groups: autograft and plate (38 cases, group A), allograft and plate (44 cases, group B), and Zero-P (48 cases, group C). Maintenance of lordosis, extent of subsidence, and fusion were evaluated radiologically and compared among preoperative, postoperative, and final follow-up time points. In addition, changes in Visual Analog Scale (VAS) and Neurologic Disability Index (NDI) scores and the presence of complications were evaluated for clinical analysis. RESULTS: Operation time was significantly less in group C (p = 0.007, 0.002). Maintenance of entire and segmental lordosis after surgery was better in groups A and B compared with group C (p = 0.002, 0.001); however, the extent of loss of lordosis from the surgery to the final follow-up did not show any significant differences. Regarding the extent of subsidence, the increase of height between the vertebral bodies after the surgery was 3.10, 2.89, and 2.68 mm in group A, group B, and group C, respectively (p = 0.14), and changed to - 1.27, - 2.41, and - 1.2 mm at the final follow-up (p = 0.012). VAS and NDI scores were improved from 7.2 to 3 and 34 to 12, respectively, but there were no significant differences. Nonunion occurred in two cases in both group B and group C. In terms of clinical complications, two cases of persistent donor site pain were found in group A; one case of persistent dysphagia was found in both group A and group B. CONCLUSION: Anterior cervical fusion using Zero-P has a shorter operation time and less subsidence compared with conventional surgical techniques. Thus it can be considered a useful technique for the surgical treatment of degenerative cervical disease.

Analysis of progression of cervical OPLL using computerized tomography: typical sign of maturation of OPLL mass.

OBJECT The progression of cervical ossification of the posterior longitudinal ligament (OPLL) can lead to increase in the size of the OPLL mass and aggravation of neurological symptoms. In the present study, the authors aimed to analyze the progression of cervical OPLL by using CT imaging, elucidate the morphology of OPLL masses, and evaluate the factors associated with the progression of cervical OPLL. METHODS Sixty patients with cervical OPLL were included. All underwent an initial CT examination and had at least 24 months' follow-up with CT. The mean duration of follow-up was 29.6 months. Fourteen patients (Group A) had CT evidence of OPLL progression, and 46 (Group B) did not show evidence of progression on CT. The 2 groups were compared with respect to the following variables: sex, age, number of involved segments, type of OPLL, and treatment methods. The CT findings, such as the connection of an OPLL mass with the vertebral body and formation of trabeculation in the mass, were evaluated. RESULTS Sex and treatment modality were not associated with OPLL progression. The mean age of the patients in Group A was significantly lower than that in Group B (p = 0.03). The mean number of involved segments was 5.3 in Group A and 3.6 in Group B (p = 0.002). Group A had a higher proportion of cases with the mixed type of OPLL, whereas Group B had a higher proportion of cases with the segmental type (p = 0.02). A connection between the vertebral body and OPLL mass and trabeculation formation were more common in Group B (p < 0.01). CONCLUSIONS Progression of cervical OPLL is associated with younger age, involvement of multiple levels, and mixed-type morphology. OPLL masses that are contiguous with the vertebral body and have trabecular formation are useful findings for identifying masses that are less likely to progress.

Reversal of paraplegia after anterior decompression in a patient underwent posterior decompression and fusion for thoracic ossification of posterior longitudinal ligament.

This report describes a rare clinical entity, thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL), and its management. A 40-year-old woman presented with thoracic myelopathy due to OPLL, extending from T2-T9. We performed a posterior laminectomy and instrumented fusion. However, postoperative paraplegia occurred within 36 h post-surgery. Emergent anterior decompression and interbody fusion was performed via the trans-thoracic approach. Neurological deterioration was reversed following this anterior procedure. Posterior decompression and instrumented fusion for thoracic OPLL is less technically demanding and presents a lower risk of neurological complications. However, some controversies remain regarding the prevalence and management of postoperative neurological deterioration associated with this technique. Our patient showed recovery with subsequent anterior decompression when paraplegia occurred after posterior decompression and fusion to treat thoracic OPLL. Additional anterior decompression should be considered when posterior decompression and fusion lead to neurological deterioration.

The Relationship between Increased Intervertebral Disc Height and Development of Postoperative Axial Neck Pain after Anterior Cervical Fusion.

OBJECTIVE: To evaluate the relationship between postoperative increase in intervertebral disc space height (IVH) and posterior axial neck in cases of degenerative cervical disease treated with anterior cervical discectomy and fusion (ACDF). METHODS: A total of 155 patients who underwent ACDF with more than 1 year follow up were included. Radiologically, IVH and interfacet distance (IFD) of the operated segment were measured preoperatively and postoperatively. We clinically evaluated neck and arm pains according to visual analogue scale (VAS) scores and assessed neck disability index (NDI) scores preoperatively, postoperatively, at 3 months, 6 months, and 1 year postoperatively. The relationship between radiological parameters, and clinical scores were analyzed using a regression analysis. RESULTS: The mean increase in IVH was 2.62 mm, and the mean increase in IFD was 0.67 mm. The VAS scores for neck pain preoperatively, postoperatively, and at 3 months, 6 months, 1 year postoperatively were 4.46, 2.11, 2.07, 1.95, and 1.29; those for arm pain were 5.89, 3.24, 3.20, 3.03, and 2.18. The NDI scores were improved from 18.52 to 7.47. No significant relationship was observed between the radiological evaluation results regarding the increase in intervertebral height or interfacet distance and clinical changes in VAS or NDI scores. CONCLUSION: The increase in intervertebral space or interfacet distance by the insertion of a large graft material while performing ACDF for the treatment of degenerative cervical disease was not related with the change in VAS scores for neck and arm pains and NDI scores postoperatively and during the follow-up period.