The relationship between the cervical spinal canal diameter and the pathological changes in the cervical spine

A congenitally narrow cervical spinal canal has been established as an important risk factor for the development of cervical spondylotic myelopathy. However, few reports have described the mechanism underlying this risk. In this study, we investigate the relationship between cervical spinal canal narrowing and pathological changes in the cervical spine using positional magnetic resonance imaging (MRI). Two hundred and ninety-five symptomatic patients underwent cervical MRI in the weight-bearing position with dynamic motion (flexion, neutral, and extension) of the cervical spine. The sagittal cervical spinal canal diameter and cervical segmental angular motion were measured and calculated. Each segment was assessed for the extent of intervertebral disc degeneration and cervical cord compression. Based on the sagittal canal diameter, the subjects were classified into three groups: A, subjects with a congenitally narrow canal, diameter of less than 13 mm; B, subjects with a normal canal, diameter of 13–15 mm; C, subjects with a wide canal, diameter of more than 15 mm. When compared with Groups A and B, the disc degeneration grades at the C3-4, C5-6, and C6-7 segments and the cervical cord compression scores at the C3-4 and C5-6 segments showed significant differences. Additionally, when compare with Groups A and C, the disc degeneration grades at all segments, except C2-3, and the cervical cord compression scores at all segments, except C2-3, showed significant differences. With respect to the cervical kinematics, few differences in the kinematics were observed between Groups B and C, however, the kinematics in Group A was different with other two groups. In Group A, the segmental mobility at the C4-5 and C6-7 segments were significantly higher than those observed in Group B, and the segmental mobility at the C3-4 segment was significantly lower than that observed in Groups B or C. We demonstrated the unique pathological and kinematic traits of cervical spine that exist in a congenitally narrow canal. We hypothesize that kinematic trait associated with a congenitally narrow canal may greatly contribute to pathological changes in the cervical spine. Our results suggest that cervical spinal canal diameter of less than 13 mm may be associated with an increased risk for development of pathological changes in cervical intervertebral discs. Subsequently, the presence of a congenitally narrow canal can expose individuals to a greater risk of developing cervical spinal stenosis.     

Feasibility of low-radiation-dose CT for abdominal examinations with hybrid iterative reconstruction algorithm: low-contrast phantom study

Our purpose in this study was to evaluate the image quality of low-radiation-dose CT using hybrid iterative reconstruction (HIR), and to compare the results with those of filtered back projection (FBP) at routine doses. We measured the mean values and standard deviation of the CT numbers within and outside a 15-mm low-contrast object cylinder at 1.0 % contrast level. The noise reduction levels of the HIR were 1 (weak) to 7 (strong). Visual inspection of the low-contrast detectability was done by six radiologic technologists. The low-contrast detectability of the cylinder at the 1.0 % contrast level with HIR at all mAs levels was equal to that obtained with FBP, and thus the use of HIR did not result in any improvement of low-contrast detectability.     

Factors causing prolonged hypoperfusion after transient ischemic attack

Even during the symptom-free stages, patients with a TIA often experience cerebral blood flow disturbances. In order to evaluate the factors which cause this abnormality, we studied the cerebral blood flow disturbance, anatomy and clinical status in 21 patients after TIAs. The results of^99mTc-hexamethyl-propylene-amine oxime SPECT were compared with CT, cerebral angiogram, cerebrovascular risk factors and clinical findings to determine which factor is most responsible for the hypoperfusion of brain after TIA. The overall sensitivity rates in detecting a lesion were 67% in SPECT and 19% in CT. The hypoperfused area tended to be large in patients who had intracranial, severe stenotic, multiple, or hemodynamically significant arterial lesions on the ipsilateral side. No such relationships were found between other examinations. We conclude that hypoperfusion after TIA essentially reflects a continuous cerebral blood flow disturbance that can be attributed to atherosclerosis of the cerebral arteries, with subsequent embolic and/or hemodynamic cerebral ischemia, although there may be a variety of processes.     

Hand assisted retroperitoneoscopic nephroureterectomy: comparison with the open procedure

PURPOSE: We report our initial experience with hand assisted retroperitoneoscopic nephroureterectomy for upper urinary tract transitional cell carcinoma and compared our results to those of a contemporary series of open nephroureterectomy. MATERIALS AND METHODS: Clinical data on 34 consecutive patients who underwent hand assisted retroperitoneoscopic nephroureterectomy were reviewed and compared with those on 34 who underwent open nephroureterectomy. All specimens were extracted intact. RESULTS: Total operative time was similar in the 2 groups (233 versus 236 minutes). Estimated blood loss was significantly less in the hand assisted laparoscopy group (236 versus 427 ml.). During convalescence the frequency of parenteral analgesia postoperatively was significantly lower in the laparoscopy group than in the open surgery group. The former patients had a significantly shorter interval to oral intake and ambulation as well as a shorter hospital stay and convalescence compared with those who underwent open surgery. In each group the complication rate was 12% (4 of 34 cases). In the hand assisted laparoscopy group 1 conversion to an open procedure was due to bleeding. There was recurrence in 4 of the 34 patients (12%) in the laparoscopy group, including 2 with bladder recurrence and 2 with metastases, at an average followup of 13.1 months. CONCLUSIONS: Hand assisted retroperitoneoscopic nephroureterectomy is an effective and safe alternative to open nephroureterectomy for upper urinary tract transitional cell carcinoma.     

Prone positioning improves distribution of pulmonary perfusion: noninvasive magnetic resonance imaging study in healthy humans

The purpose of this study was to evaluate the effects of prone positioning on pulmonary perfusion using flow-sensitive alternating inversion recovery (FAIR), a noninvasive magnetic resonance imaging technique that requires no contrast medium. Seven healthy volunteers were studied in the supine and prone positions under three respiratory conditions: normal breathing of room air, unassisted breathing of 45% O₂, and controlled mechanical ventilation (CMV) with positive end-expiratory pressure. Signal intensities (SIs) were obtained from ventral, middle, and dorsal regions on sagittal lung images and dependent/nondependent SI ratios were calculated to evaluate pulmonary perfusion distribution. In the supine position, SIs increased significantly from the ventral to dorsal region under all three respiratory conditions and prone positioning inverted the perfusion distribution under all conditions. Right lung SI ratios were 2.34 ± 0.29, 2.74 ± 0.66, and 2.42 ± 0.73 in the supine position and 1.68 ± 0.48, 1.78 ± 0.36, and 1.92 ± 0.21 in prone for room air, 45% O₂, and CMV, respectively. The difference between supine and prone positions was statistically significant. The left lung showed a similar pattern and the difference was significant only under CMV. No difference was observed between the different respiratory conditions in both lungs. This study demonstrated that the distribution of pulmonary perfusion was more uniform in prone than in the supine position.     

Simultaneous blockade of co-stimulatory signals, CD28 and ICOS, induced a stable tolerance in rat heart transplantation

An inducible co-stimulator (ICOS), a recently identified co-stimulatory receptor with a close structural homology of CD28 and CTLA4, is expressed on activated T cells. Anti-ICOS antibody was demonstrated to be effective on prolongation of graft survival after liver transplantation in rats. In this study, we investigated the potency of tolerance induction using the antibody combined with a recombinant adenovirus vector containing CTLA-4Ig cDNA (AdCTLA-4Ig) in rat heart transplantation model. Using a DA-to-Lewis rat heart transplantation model, an anti-rat ICOS antibody and AdCTLA-4Ig were simultaneously administered i.v. into recipients. The tissue specimens from the grafts were removed on various days after transplantation for histological evaluation. Donor-strain skin and heart grafts, and third-party heart allografts were challenged in the recipients with a long-term surviving graft. Splenocytes from the tolerance-induced recipients were used for adoptive transfer study. Anti-ICOS antibody alone did not prolong the survival of heart allograft. AdCTLA-4Ig monotherapy significantly prolonged the survival of heart allograft (Group 4). With a combination of Anti-ICOS antibody and AdCTLA-4Ig, all recipients were resulted in a long-term allograft acceptance for more than 200 days (Group 8). When challenged donor-strain skin grafts in the tolerant rats of Group 4, the skin was rejected, which also lead to a rejection of primary heart allografts. The recipients in Group 8 also rejected donor-strain skin grafts with no rejection of the primary heart grafts. These recipients accepted secondary heart grafts from donor-strain but not third-party. In Group 8 long-term survival recipients showed a high population of CD4+CD25+ regulatory T cell in peripheral blood, and in adoptive transfer study subtraction of these CD4+CD25+ T cells accelerate the rejection of heart graft in secondary irradiated recipients. The present results demonstrated that anti-ICOS antibody combined with AdCTLA-4Ig potently induces a stable immune tolerance after heart allografting in rat, which is mediated by the induction of CD4+CD25+ regulatory T cells. This strategy may be attractive for clinical employment to induce transplantation tolerance.     

Risk factors for acute rejection in living donor liver transplantation

The influence of human leukocyte antigen (HLA) compatibility and lymphocytotoxic crossmatch on acute rejection in living donor liver transplantation (LDLT) has not been well examined. We analyzed 100 consecutive adult LDLT cases. The patient and graft survival rates and post-operative complications were assessed. The relation between the incidence of acute rejection and some clinical factors including HLA and lymphocytotoxic matching was also examined. Patients with HLA DR zero mismatching (p = 0.02) or negative T-lymphocytotoxic crossmatch (p = 0.04) had a significantly lower chance of rejection within 6 wk after LDLT. However the results had no influence on the patient survival. Our results demonstrate that in LDLT, a graft from an HLA-DR zero mismatching or negative T-lymphocytotoxic crossmatch might be advantageous because of the decreased probability of early acute rejection.     

A simple technique ligating the corresponding inflow and outflow vessels during anatomical left hepatectomy

Background Massive bleeding remains one of main factors of morbidity and death in liver resections. For this reason, the Pringle maneuver or total vascular exclusion is commonly used during liver resection. However, ischemic damage is still a major problem. Some surgeons used the “glissonean” approach for bleeding control, but the technique is tedious and also time consuming, with high incidence of bile leaks in the postoperative period. The aim of this paper is to describe a new bleeding control technique, rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection during anatomical left liver resection and to analyze the feasibility, blood loss, transfusion requirements, and postoperative complications. Materials and methods During the past 18 years, we used the new hemorrhage control technique in left liver resection in 630 patients with malignant or benign tumors. Results The median blood loss in all 630 patients was 110 ± 250 ml (range 50–750), and no patient required blood transfusion. The median total operative time was 77 ± 35 min (range 25–155). No bile leaks and liver failure of the patients occurred postoperatively. There was no death within 30 postoperative days. Conclusion The rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection is a feasible, safe, and bloodless technique during the left liver resection. A commentary on this paper is available at     

Arthroscopic findings in Maisonneuve fractures

Background A Maisonneuve fracture consists of a proximal fibular fracture with associated syndesmotic ligament disruption and injury to the medial ankle structures. The treatment outcome is good in most cases, although poor results have also been reported. The purpose of this study was to investigate intra-articular lesions in Maisonneuve fractures. Methods The subjects consisted of four patients (four ankle joints) who had suffered a Maisonneuve fracture and had undergone surgical treatment between June 2005 and November 2005. The mean age was 24. 2 years. At the time of surgery, we performed ankle arthroscopy and determined the presence of tibiofibular syndesmosis disruption, cartilaginous damage, and ligament damage. Lesions of the articular cartilage were graded by depth as determined by inspection and probing. Results All four of the cases had cartilaginous damage to the medial section of the talar dome. Lateral lesions were not observed. Chondral debris and hemarthrosis were noted in virtually all cases, and each ankle had a tear on the anterior inferior tibiofibular ligament and interosseous tibiofibular ligament. No patients had a tear of the posterior inferior tibiofibular ligament. Conclusions Arthroscopy was useful in identifying associated intra-articular lesions in Maisonneuve fractures.