Prognostic value of changes in spinal cord signal intensity on magnetic resonance imaging in patients with cervical compressive myelopathy

Background contextSignal intensity on preoperative cervical magnetic resonance imaging (MRI) of the spinal cord has been shown to be a potential predictor of outcome of surgery for cervical compressive myelopathy. However, the prognostic value of such signal remains controversial. One reason for the controversy is the lack of proper quantitative methods to assess MRI signal intensity.PurposeTo quantify signal intensity and to correlate intramedullary signal changes on MRI T1- and T2-weighted images (WIs) with clinical outcome and prognosis.Study designRetrospective case study.Patient samplePatients (n=148; cervical spondylotic myelopathy, n=102 and ossified posterior longitudinal ligament, n=46) who underwent surgery for cervical compressive myelopathy and had high signal intensity change on sagittal T2-WI MRI before surgery between 2006 and 2010.Outcome measureNeurologic assessment was conducted with the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. The rate of neurologic improvement was calculated with the use of preoperative and postoperative JOA scores.MethodsQuantitative analysis of MRI signal on both T1- and T2-WIs via use of the signal intensity ratio (SIR; signal intensity of lesion relative to that at C7-T1 disc level) was performed. Correlations between SIR on T1- and T2-WIs and preoperative JOA score, JOA improvement rate, disease duration, and MRI morphologic classification (cystic or diffuse type) were analyzed. Multivariate regression analysis for JOA improvement rate was also analyzed. In a substudy, 25 patients underwent follow-up MRI starting from 6 months after surgery to analyze the relationship between changes in SIR on follow-up MRI and clinical outcome.ResultsSIR on T1-WIs, but not SIR on T2-WIs, correlated with postoperative neurologic improvement. The disease duration correlated negatively with SIR on T1-WIs and JOA improvement rate but not with SIR on T2-WIs. SIR on T2-WIs of “cystic type” was significantly greater than of “diffuse type,” but SIR on T1-WI and JOA improvement rate were not different in the two types. Stepwise multivariate regression analysis indicated that SIR on T1-WIs and long disease duration were significant predictors of postoperative neurologic outcome. SIR on follow-up T1-WI and changes in SIR on T1-WI after surgery correlated positively with postoperative improvement rate. SIR on follow-up T2-WI and changes on T2-WI correlated negatively with postoperative neurologic improvement.ConclusionsOur results suggest that low intensity signal on preoperative T1-WIs but not T2-WIs correlated with poor postoperative neurologic outcome. Furthermore, decreased signal intensity on postoperative T1-WIs and increased signal intensity on postoperative T2-WIs are predictors of poor neurologic outcome.     

Intracranial Pial Arteriovenous Fistula Caused by Dural Tenting: Case Report

We describe a rare case where a patient developed intracranial pial arteriovenous (AV) fistula due to dural tenting. The patient was a 63-year-old woman who had undergone neck clipping for an unruptured middle cerebral artery (MCA) aneurysm. The surgery was performed without any problems and her postoperative course was uneventful. Two weeks after cerebral angiography operation revealed a pial AV fistula fed by the right MCA and drained into the vein of Trolard through the Sylvian vein which had not existed before surgery. Being diagnosed as de novo pial AV fistula, surgical repair was performed. The AV fistula was located just beneath the dural tenting. The fistulous point was confirmed with fluorescein video angiography and obliterated using a clip. Although rare, we should pay attention to the AV fistula due to dural tenting as the complications of cranial surgery.     

Biomechanics in uniaxial compression of three distal radius volar plates

PURPOSE: A new fixed-angle volar plate for a dorsally displaced distal radius fracture was designed with the aim of avoiding soft tissue problems due to dorsal plating. The purpose of this study was to compare the biomechanical properties of this new plate with 2 existing volar plates in a cadaver model. METHODS: Three different plates were applied on surgically simulated unstable extra-articular distal radius fractures in formalin-fixed cadaver radiuses. Group 1 (volarly placed AO titanium Distal Radius plates [Synthes Ltd, Paoli, PA]; n = 6), group 2 (volarly placed titanium Symmetry plates [DePuy ACE Co, El Segundo, CA]; n = 6), and group 3 (volarly placed newly designed titanium plates; n = 6) were tested to failure under axial compression with a materials testing machine. Specimens of all 3 groups had similar bone mineral density. RESULTS: Group 3 specimens had significantly greater elastic limit and ultimate strength than the other 2 groups. Specimens of group 3 had the greatest rigidity, although this was statistically insignificant compared with the other 2 groups. All plates (groups 1, 2, 3) failed in apex volar angulation. CONCLUSIONS: The newly designed plate fixation system is the strongest of the systems tested and may offer adequate stability for the treatment of a distal radius fracture in which the dorsal and/or volar metaphyseal cortex is comminuted severely.     

New method of measuring presampling MTF by fourier transform of square-wave chart image

We developed an easy method of measuring the presampling modulation transfer function (MTF) using the square wave chart in digital radiography. In this method, the presampling MTF is measured by Fourier transform of image data of the square wave chart. When Fourier analysis of the sampling data of a square wave is carried out, it is generally difficult to find the starting point and terminal point of the periodic data that should be extracted because of an insufficient number of data. To solve this problem, interpolated data were calculated by using a window function of the frequency domain. The aliasing error was avoided using a characteristic such that the square wave has discrete frequency components. The accuracy of this method was investigated by computer simulation study. Actual measurement of the presampling MTF by this method was also performed with a CR system. These studies indicated the effectiveness of our proposed method in terms of accuracy and ease of use.     

Adult transmesenteric hernia: report of two cases

Transmesenteric hernia is a rare cause of bowel obstruction in adults. We herein describe two cases that occurred in adult women, ages 27 and 19. Both cases presented with abdominal pain without muscular defense signs. Computed tomography of both cases showed features of small bowel obstruction by an internal hernia. A laparotomy showed mesenteric defects of the mesentery of the ileum in the former case and the mesentery of the transverse colon in the latter case, with a herniating ileum. The involved small bowel was viable in both cases, and the bowel was pulled out of the mesenteric defect without resection. The mesenteric defects were then successfully repaired.     

Recurrent mediastinal desmoid tumor treated by surgical resection ; report of a case

We report a rare case of mediastinal desmoid tumor in a 17-year-old man. The patient was a 17-year old man who had underwent surgery for mediastinal tumor at our hospital 2 years before. The tumor was diagnosed as a solitary fibrous tumor of the mediastinum. After 2 years, chest computed tomography(CT) and magnetic resonance imaging( MRI) showed a mass at the previously resected site. Surgery was performed again under the diagnosis of recurrent tumor. The tumor densely adhered to the superior vena cava, right innominate vein, pericardium, and the right lung. The tumor was completely resected with the aid of the partial extracorporeal circulation. Finally, both previously resected tumor and the recurrent tumor were diagnosed pathologically as desmoid tumors.     

Huge inflammatory pseudotumor of the spleen with postoperative portal vein thrombosis: report of a case

We report the rare case of a splenic inflammatory pseudotumor associated with massive splenomegaly, diagnosed after surgery. A 51-year-old woman was admitted to our hospital for investigation of anemia. Physical examination revealed a palpable left upper quadrant mass. Computed tomography and magnetic resonance imaging showed a splenic mass, 20 cm in diameter. We performed splenectomy for both diagnosis and treatment. The spleen weighed 2400 g, and histologic examination of the mass confirmed an inflammatory pseudotumor. Portal vein thrombosis (PVT) developed the day after surgery, but resolved with anticoagulation therapy. This case highlights that there is a risk of PVT after splenectomy in patients with massive splenomegaly, and that anticoagulant therapy should be initiated promptly.     

Significance of low-level DSA detected by solid-phase assay in association with acute and chronic antibody-mediated rejection

We sought to clarify the controversial issue of whether detecting low‐level anti‐donor‐specific HLA antibody (HLA‐DSA) by single‐antigen flow‐bead assay (SAFB) may have a potential role in reducing acute and chronic antibody‐mediated rejection (AMR). We retrospectively studied the preoperative serum of ABO‐compatible living kidney transplantation recipients transplanted between 2001 and 2004 by SAFB using a Luminex platform. HLA‐DSA was detected only by SAFB in 24 patients, although all of them showed negative T‐cell and B‐cell complement‐dependent cytotoxicity (CDC) crossmatches. The HLA‐DSA patients went on to have surprisingly high levels of acute and chronic AMR despite being only weakly sensitized (acute AMR, 33.3%; chronic AMR, 41.7%). After 2005, we implemented SAFB routinely and any patient having a positive HLA‐DSA was considered to be a desensitization candidate. The 52 patients found to have HLA‐DSA underwent kidney transplantation after prior treatment with a single dose of rituximab (RIT) and three or four sessions of double‐filtration plasmapheresis (DFPP) in addition to regimens commonly used between 2001 and 2004. After 2005, there was a significant reduction in the occurrence of acute and chronic AMR (acute AMR, 4.7%, P < 0.001; chronic AMR, 4.7%, P < 0.001). The 5‐year graft survival rate also improved after implementing SAFB (83.3–98.1%, P = 0.032). The RIT/DFPP‐induction protocol may improve graft survival even in patients with low‐level DSA.     

A model to evaluate toxic factors influencing islets during collagenase digestion: the role of serine protease inhibitor in the protection of islets

The recovery of all of the islets contained in a pancreas is the goal of islet isolation for transplantation. This study reveals an environment that injures the isolated islets during digestion and proposes a new model for optimal islet isolation. Islets were isolated from Wistar rat pancreases by stationary collagenase digestion while the digestion time was varied at 15, 30, 60, and 120 min. The digested pancreas and islets were analyzed histologically and adenosine nucleotides were measured. Overnight cultured islets (40 islets) were cocultured for 30 min with the supernatants obtained from pancreatic collagenase digestion at different digestion periods in order to assess the toxic environment. The peak yields of islets were obtained at 30 min of digestion. The histological study of digested pancreas showed that the exocrine cells lost their cellular integrity at 120 min of digestion, but the islet cells were left intact. Accordingly, the ATP levels of the pancreatic tissue decreased during the digestion period. The coculture experiment demonstrated that the islets cultured with the supernatants from the collagenase digestion showed digestion time-dependent disruption of the cellular integrity of islets in accordance with a rapid decrease of ATP levels in the islets. The addition of serine protease inhibitors into this coculture clearly showed protection of islets, which maintained high ATP levels in association with intact membrane integrity as assessed by AO/PI staining. Morphological deterioration of islets as well as a marked ATP decrease was evident in the entire digested pancreas as well as in islets cocultured in the supernatants from the collagenase digestion. Various factors toxic to the islets can therefore be analyzed in future experiments using this coculture model for obtaining a good yield of viable islets.