Hereditary hemorrhagic telangiectasia with hepatic arteriovenous shunt diagnosed due to liver damage

A 53-year-old woman was diagnosed with liver dysfunction in August 20XX. Computed tomography (CT) revealed multiple hepatic AV shunts, and she was placed under observation. In March 20XX + 3, she developed back pain, and CT performed during an emergency hospital visit showed evidence of intrahepatic bile duct dilatation. She was referred to our gastroenterology department in May 20XX + 3. We conducted investigations on suspicion of hereditary hemorrhagic telangiectasia (HHT) with hepatic AV shunting based on contrast-enhanced CT performed at another hospital. HHT is generally discovered due to epistaxis, but there are also cases where it is diagnosed during examination of liver damage.

Memantine administration prevented chorea movement in Huntington's disease: a case report

BACKGROUND

Huntington's disease is an autosomal dominant inherited disorder characterized by personality changes (such as irritability and restlessness) and psychotic symptoms (such as hallucinations and delusions). When the personality changes become noticeable, involuntary movements (chorea) also develop. The disease is caused by the CAG repeat expansion in the coding region of the HTT gene, and the diagnosis is based on the presence of this expansion. However, there is currently no effective treatment for the progression of Huntington's disease and its involuntary motor symptoms. Herein, we present a case in which memantine was effective in treating the chorea movements of Huntington's disease.

CASE PRESENTATION

A 75-year-old Japanese woman presented to the hospital with involuntary movements of Huntington's disease that began when she was 73 years old. In a cerebral blood flow test (N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography), decreased blood flow was observed in the precuneus (anterior wedge) and posterior cingulate gyrus. Usually, such areas of decreased blood flow are observed in patients with Alzheimer's-type dementia. So, we administered memantine for Alzheimer's-type dementia, and this treatment suppressed the involuntary movements of Huntington's disease, and the symptoms progressed slowly for 7 years after the onset of senility. In contrast, her brother died of complications of pneumonia during the course of Huntington's disease.

CONCLUSIONS

We recorded changes in parameters such as the results of the N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography and gait videos over 7 years. Treatment with memantine prevented the chorea movement and the progression of Huntington's disease. We believe this record will provide clinicians with valuable information in diagnosing and treating Huntington's disease.

Impact of the Number of Lymph Nodes Examined on Differences in Survival for Surgically Treated Gastric Cancer Patients Between the US and Japan Using Nationwide Databases

Background: Although incidence and mortality have decreased, gastric cancer (GC) is still a public health issue globally. The international collaborative study for cancer survival using population-based cancer registry showed that the survival of GC was higher in Korea and Japan than other countries, including the United States of America (US). Aim: We examined the determinant factors of the high survival in Japan, compared with the US, with particular focus on the impact of the number of lymph nodes (LNs) examined for surgically treated patients. Methods: We obtained data on 88,447 cases from the nationwide GC registration project, the Japanese Gastric Cancer Association (JGCA), from 2004-2007. We also obtained 18,995 GC cases from US population-based cancer registry data from the Surveillance, Epidemiology, and End Results Program (SEER), diagnosed from 2004-2010. We estimated five-year relative survival and applied a multivariate excess hazard model to compare the two countries. We considered the effect of LNs examined on differences in survival. Results: Five-year relative survival in Japan was 79.8%, compared with 40.1% in the US. After controlling for confounding factors, we still observed significantly higher survival in Japan. The distribution of number of LNs examined showed notable differences between two countries. In over 50% of patients in the US, only 1 to 15 LNs were examined. A higher number of LNs examined showed better survival in both countries. The differences in excess death from cancer between countries were reduced in the category when more than 30 LNs were examined. Conclusion: Although it is difficult to remove biases to compare the two countries, stage migration, related to the more detailed retrieving strategy for LNs in Japan, is a key explanation for high survival in Japan.

Proton pump inhibitor after endoscopic resection for esophageal squamous cell cancer: multicenter prospective randomized controlled trial

BACKGROUND

Whether proton pump inhibitors (PPIs) relieve heartburn or precordial pain after endoscopic resection (ER) for esophageal squamous cell carcinoma (ESCC) remains unclear. The aim of this study was to investigate the efficacy of PPI therapy for these symptoms after ER for ESCC.

METHODS

We conducted a multicenter prospective randomized controlled trial among 15 hospitals in Japan. In total, 229 patients with cT1a ESCC were randomly assigned to receive PPI therapy for 5 weeks after ER (the PPI group, n = 115) or follow-up without PPI therapy (the non-PPI group, n = 114). The primary end point was the incidence of gastroesophageal reflux disease (GERD)-like symptoms after ER from a self-reported questionnaire (Frequency Scale for Symptoms of GERD). Secondary end points were ulcer healing rate at 5 weeks, incidence of pain, improvement rate of symptoms in those who started PPI therapy because of GERD-like symptoms in the non-PPI group, and adverse events.

RESULTS

No significant difference was observed in the incidence of GERD-like symptoms after ER between the non-PPI and PPI groups (30 % vs 34 %, respectively). No significant differences were observed in the ulcer healing rate at 5 weeks (84 % vs 85 %) and incidence of pain within 1 week (36 % vs 45 %). In nine of ten patients (90 %) who started PPI therapy because of GERD-like symptoms in the non-PPI group, PPI administration relieved GERD-like symptoms. No adverse events related to PPI administration were observed.

CONCLUSION

PPI therapy is not efficacious in reducing symptoms and did not promote healing of ulcers in patients undergoing ER for ESCC.

Development and external validation of a nomogram for overall survival after curative resection in serosa-negative, locally advanced gastric cancer

BACKGROUND

Few nomograms can predict overall survival (OS) after curative resection of advanced gastric cancer (AGC), and these nomograms were developed using data from only a few large centers over a long time period. The aim of this study was to develop and externally validate an elaborative nomogram that predicts 5-year OS after curative resection for serosa-negative, locally AGC using a large amount of data from multiple centers in Japan over a short time period (2001-2003).

PATIENTS AND METHODS

Of 39 859 patients who underwent surgery for gastric cancer between 2001 and 2003 at multiple centers in Japan, we retrospectively analyzed 5196 patients with serosa-negative AGC who underwent Resection A according to the 13th Japanese Classification of Gastric Carcinoma. The data of 3085 patients who underwent surgery from 2001 to 2002 were used as a training set for the construction of a nomogram and Web software. The data of 2111 patients who underwent surgery in 2003 were used as an external validation set.

RESULTS

Age at operation, gender, tumor size and location, macroscopic type, histological type, depth of invasion, number of positive and examined lymph nodes, and lymphovascular invasion, but not the extent of lymphadenectomy, were associated with OS. Discrimination of the developed nomogram was superior to that of the TNM classification (concordance indices of 0.68 versus 0.61; P < 0.001). Moreover, calibration was accurate.

CONCLUSIONS

We have developed and externally validated an elaborative nomogram that predicts the 5-year OS of postoperative serosa-negative AGC. This nomogram would be helpful in the assessment of individual risks and in the consideration of additional therapy in clinical practice, and we have created freely available Web software to more easily and quickly predict OS and to draw a survival curve for these purposes.

Feasibility of endoscopic mucosal resection as salvage treatment for patients with local failure after definitive chemoradiotherapy for stage IB, II, and III esophageal squamous cell cancer

Local failure after definitive chemoradiotherapy (CRT) for stage IB, II, and III esophageal cancer is one of the causes of poor outcome. Endoscopic mucosal resection (EMR) is an effective treatment for superficial esophageal cancer. However, its feasibility as a salvage treatment for local recurrent or residual tumors after definitive CRT for stage IB, II, and III esophageal cancer remains unclear. Between January 2000 and February 2008, 274 patients with stage IB, II, and III esophageal squamous cell cancer excluding T4 received definitive CRT at the National Cancer Center Hospital, Japan. Of these patients, nine patients with local recurrence after achieving complete response and two patients with residual tumor underwent salvage EMR. The technique of salvage EMR involved a strip biopsy method. We retrospectively reviewed the 11 patients (13 lesions). Characteristics of all 11 patients were as follows: median age of 69 (range: 45-78); male/female: 10/1; baseline clinical stage (Union for International Cancer Control 7th) IB/IIA/IIB/III: 1/3/7/0. The depth of resected tumor was limited to the mucosal layer in seven lesions and submucosal in six lesions. En bloc resection was performed on six lesions (46%). The vertical margin was free of cancer cells in 11 lesions (84.6%). No major complications, such as hemorrhage requiring blood transfusion and perforation, were experienced. At a median follow-up period of 38.9 months (range: 5.3-94 months) after salvage EMR, no recurrence was detected in six patients (54%). Local recurrence was detected in five patients (27%). Of these patients, two had lung metastasis simultaneously, and one was also detected lung metastasis 2 months after the detection of local recurrence. The 5-year survival rate after salvage EMR was 41.6%. Salvage EMR is a feasible treatment option for local recurrent or residual lesions after definitive chemotherapy and/or radiotherapy for stage IB, II, and III esophageal squamous cell cancer.

Is endoscopic submucosal dissection an effective treatment for operable patients with clinical submucosal invasive early gastric cancer?

BACKGROUND AND STUDY AIMS

Gastrectomy with lymph node dissection is the gold standard curative treatment for clinical submucosal invasive early gastric cancer (cSM EGC), but a relatively small number of operable patients with cSM EGC have undergone endoscopic submucosal dissection (ESD) instead because they refused surgery. The aim of this study was to determine the effectiveness of ESD in these operable patients.

METHODS

The therapeutic outcomes of ESD were retrospectively assessed for 38 patients with 38 operable cSM EGC lesions who initially refused surgery at the National Cancer Center Hospital, Tokyo, from January 1999 to December 2008.

RESULTS

The en bloc resection rate was 84.2% (32 lesions) and the complete (R0) resection rate was 63.2% (24 lesions). A total of 33 lesions (86.8%) involved submucosal invasion on pathology. Resection was non-curative in 34 patients (89.5%), 22 of whom (64.7%) underwent subsequent gastrectomy after the need for such surgery was carefully explained to them again. The median follow-up period was 73.2 months (range 3-115 months). Local recurrence was detected in one patient, distant metastasis in two patients, and both local recurrence and distant metastasis were detected in one patient. None of these four patients with recurrence (10.5%) had undergone surgery when their recurrent disease was detected and all of them died from gastric cancer. The 5-year cause-specific survival rate for all patients was 91.8%.

CONCLUSION

The 5-year cause-specific survival rate for all patients was lower than the previously reported rate of 96.7% for pathologically submucosal invasive EGC patients after gastrectomy; therefore, ESD appears to have been an ineffective treatment for operable patients with cSM EGC.

Endoscopic resection of early gastric cancer treated by guideline and expanded National Cancer Centre criteria

BACKGROUND

Criteria for endoscopic resection in patients with early gastric cancer (EGC) have been expanded recently by the National Cancer Centre (NCC). This study compared long-term outcomes in patients with EGC who underwent endoscopic treatment according to guideline criteria with those treated according to expanded criteria.

METHODS

Baseline and outcome data from patients undergoing curative endoscopic resection for EGC between January 1999 and December 2005 were collected from electronic medical records. Survival time hazard ratios and 95 per cent confidence intervals were calculated using the Cox proportional hazards model.

RESULTS

Of 1485 patients who had a curative resection, 635 (42.8 per cent) underwent resection according to traditional criteria and 625 (42.1 per cent) according to expanded criteria. There was no significant difference in overall survival between the groups.

CONCLUSION

Patients who have treatment following the expanded criteria have similar long-term survival and outcomes to those treated according to guideline criteria.

Endoscopic resection of early gastric cancer treated by guideline and expanded National Cancer Centre criteria

BACKGROUND

Criteria for endoscopic resection in patients with early gastric cancer (EGC) have been expanded recently by the National Cancer Centre (NCC). This study compared long-term outcomes in patients with EGC who underwent endoscopic treatment according to guideline criteria with those treated according to expanded criteria.

METHODS

Baseline and outcome data from patients undergoing curative endoscopic resection for EGC between January 1999 and December 2005 were collected from electronic medical records. Survival time hazard ratios and 95 per cent confidence intervals were calculated using the Cox proportional hazards model.

RESULTS

Of 1485 patients who had a curative resection, 635 (42.8 per cent) underwent resection according to traditional criteria and 625 (42.1 per cent) according to expanded criteria. There was no significant difference in overall survival between the groups.

CONCLUSION

Patients who have treatment following the expanded criteria have similar long-term survival and outcomes to those treated according to guideline criteria.

Use of Gascon and Pronase either as a pre-endoscopic drink or as targeted endoscopic flushes to improve visibility during gastroscopy: a prospective, randomized, controlled, blinded trial

OBJECTIVE

To assess whether endoscopic flushes of the bubble-bursting agent Gascon and the mucolytic agent Pronase are as effective in terms of improving endoscopic mucosal visibility as a pre-endoscopic drink of the same agents.

MATERIAL AND METHODS

A total of 112 patients attending a Japanese tertiary referral centre for upper gastrointestinal endoscopy were randomized to receive either the standard Japanese procedure of a pre-endoscopic drink of water containing Gascon and Pronase with endoscopic flushes of 20-ml aliquots of water, or no pre-endoscopic therapy but endoscopic flushes of 20-ml aliquots of water containing Gascon, with or without Pronase as necessary.

RESULTS

Visibility scores were significantly better in the pre-endoscopic drink group than in either of the endoscopic flush groups. The group receiving a pre-endoscopic drink required fewer flushes during the procedure and there was no difference in the endoscopic time between the three groups.

CONCLUSIONS

Our results suggest that endoscopic spraying of these bubble-bursting and mucolytic agents is not able to offer equivalent improvements in endoscopic mucosal visibility when compared with the standard Japanese therapy of a pre-endoscopic drink of these agents. The addition of Pronase to the spray solution had no measurable benefit over Gascon alone. We therefore cannot recommend endoscopic spraying of mucous clearing agents over their use as a pre-endoscopic drink.

Feasibility of endoscopic mucosal resection for superficial pharyngeal cancer: a minimally invasive treatment

BACKGROUND AND STUDY AIMS

New diagnostic techniques have recently been developed so detection of superficial pharyngeal cancer is dramatically increasing and endoscopic mucosal resection (EMR) can now be performed on an experimental basis. The aim of this study was to clarify the effectiveness of EMR for superficial pharyngeal cancer.

PATIENTS AND METHODS

Between 2004 and 2007, 31 patients with 37 pharyngeal lesions underwent EMR at our hospital. EMR using a cap-fitted endoscope (EMR-C) was used on 34 lesions and strip biopsies on the remaining three. We retrospectively assessed the effectiveness of those procedures in treating superficial pharyngeal cancer.

RESULTS

Median procedure time was 45 minutes (range 20 - 180 minutes) and median hospital stay was 7 days (range 4 - 12 days). Regarding complications, one patient experienced laryngeal edema, one suffered aspiration pneumonia, and two sustained dermatitis around the mouth caused by Lugol staining. Histologically, 18 lesions were confirmed as carcinoma in situ and the other 19 lesions demonstrated microinvasion of the subepithelial tissue with lymphatic invasion in one case. During the median follow-up period of 40 months (range 21 - 62 months), two patients received radiotherapy and two patients underwent an additional EMR because of recurrent tumors. Five other patients developed metachronous superficial pharyngeal cancers, but all those lesions were resected primarily by EMR while two of the study's 31 patients died from esophageal cancer. None of the remaining 20 patients experienced any recurrent or metachronous tumors during their follow-up periods.

CONCLUSIONS

Our results indicated that EMR was a safe, effective, and minimally invasive treatment for superficial pharyngeal cancer.

The indolent course and high incidence of t(14;18) in primary duodenal follicular lymphoma

BACKGROUND

Information on the clinical behavior of the recently proposed primary duodenal follicular lymphoma (DFL) is limited.

PATIENTS AND METHODS

Demographic data, signs, symptoms, disease stage, and treatment of the patients diagnosed in National Cancer Center Hospital from 1999 to 2007 were collected and analyzed.

RESULTS

Twenty-seven patients were studied. Nineteen patients were asymptomatic at the time of diagnosis. Twenty patients had stage I disease. The histological grade was 1 or 2 in 26 patients. IgH/BCL2 fusion was shown in 20 of the examined 24 cases (83%). Fourteen patients received therapy upon diagnosis (local radiotherapy in 2 patients and chemotherapy in 12 including rituximab therapy), their response rate was 85%, and the estimated progression-free survival (PFS) rate at 3 years was 70%. One patient developed histological transformation. The other 13 patients were followed up; their estimated PFS rate at 3 years was 74%. Five among six cases responded to treatment even after progressive disease. All 27 patients have survived with a median follow-up time of 47.9 months.

CONCLUSIONS

The majority of primary DFL patients have a localized tumor of low-grade histology and are positive for t(14;18). Watchful waiting might be an alternative approach for its indolent course; however, further studies are warranted.

Risk factors for cardiac and pyloric stenosis after endoscopic submucosal dissection, and efficacy of endoscopic balloon dilation treatment

BACKGROUND AND STUDY AIMS

Bleeding and perforation are major complications of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC), but post-ESD stenosis represents a severe delayed complication that can result in clinical symptoms such as dysphagia and nausea. The aims of this study were to determine the risk factors and evaluate the clinical treatment for post-ESD stenosis.

METHODS

A total of 2011 EGCs resected by ESD at our institution between 2000 and 2005 were reviewed retrospectively. Resection was defined as cardiac when any mucosal defect was located in the squamocolumnar junction, and as pyloric when any mucosal defect was located < 1 cm from the pylorus ring. Post-ESD stenosis was defined when a standard endoscope could not be passed through the stenosis. We examined the incidence of post-ESD stenosis, its relationship with relevant factors, and the clinical course of post-ESD stenosis patients.

RESULTS

Post-ESD stenosis occurred with seven of 41 cardiac resections (17 %) and eight of 115 pyloric resections (7 %). Circumferential extent of the mucosal defect of > 3/4 and longitudinal extent > 5 cm were each significantly related to occurrence of post-ESD stenosis with both cardiac and pyloric resections. All 15 affected patients were successfully treated by endoscopic balloon dilation.

CONCLUSIONS

A circumferential extent of the mucosal defect of > 3/4 or longitudinal extent of > 5 cm in length were both demonstrated to be risk factors for post-ESD stenosis, in both cardiac and pyloric resections, and endoscopic balloon dilation was shown to be effective in treating post-ESD stenosis.

Treatment strategy after non-curative endoscopic resection of early gastric cancer

BACKGROUND

Endoscopic resection (ER) is indicated for patients with early gastric cancer who have a negligible risk of lymph node metastasis (LNM). Histological examination of the resected specimen may indicate a possible risk of LNM or a positive resection margin. These patients are considered to have undergone non-curative ER. The aim of this study was to determine the appropriate treatment strategy for such patients.

METHODS

A total of 298 patients who had non-curative ER were classified into those with a positive lateral margin only (group 1; 72 patients) and those with a possible risk of LNM (group 2; 226 patients).

RESULTS

Surgery was performed within 6 months of non-curative ER in 19 patients in group 1 and 144 in group 2. In group 1, nine patients were found to have local residual tumours, all limited to the mucosal layer without LNM. In Group 2, 13 patients had residual disease, including four local tumours without LNM, two local tumours with LNM and seven cases of LNM alone. The rate of LNM after surgery was 6.3 per cent in group 2.

CONCLUSION

Surgery remains the standard treatment after non-curative ER in patients with a possible risk of LNM.

Routine coagulation of visible vessels may prevent delayed bleeding after endoscopic submucosal dissection--an analysis of risk factors

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) has been reported to be associated with a higher complication rate than standard endoscopic mucosal resection. We aimed to clarify the risk factors for delayed bleeding after ESD for early gastric cancer (EGC).

METHODS

1083 EGCs in 968 consecutive patients undergoing ESD during a 4-year period were reviewed. Post-ESD coagulation (PEC) preventive therapy of visible vessels in the resection area, using a coagulation forceps, was introduced and mostly performed during the later 2 years. Various factors related to patients, tumors, and treatment including PEC were investigated using univariate and multivariate analysis with regard to delayed post-ESD bleeding, evidenced by hematemesis or melena, that required endoscopic treatment.

RESULTS

Delayed bleeding occurred after ESD of 63 lesions (5.8 % of all lesions and 6.5 % of patients), controlled in all cases by endoscopic hemostasis; blood transfusion was required in only one case. Tumor location in the upper third of the stomach and PEC were independent factors indicating a lower rate of delayed bleeding according to both univariate and multivariate analysis.

CONCLUSIONS

This retrospective study suggested that preventive coagulation of visible vessels in the resection area after ESD may lead to a lower bleeding rate.

Gastric perforation during endoscopic resection for gastric carcinoma and the risk of peritoneal dissemination

BACKGROUND

The potential risk of peritoneal seeding following perforation caused by endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) is unknown.

METHODS

Between January 1991 and December 2003, 90 patients suffered gastric perforation during EMR or ESD at the National Cancer Centre Hospital, Tokyo. The clinical and pathological evidence for peritoneal dissemination in these patients was assessed retrospectively.

RESULTS

Eighty-four patients were followed up at this hospital for a median of 53.6 (range 7.0-136.6) months; the remaining six patients were followed up at other institutions. In 83 patients the perforation was repaired by endoscopic clip application and seven patients underwent emergency surgery. Gastrectomy was carried out in 33 patients who had non-curative endoscopic surgery. Among these, peritoneal fluid was sampled during operation in nine patients and was cytologically negative for malignancy. The other 24 patients who had a gastrectomy did not have ascites so cytology was not performed. No peritoneal dissemination was noted during follow-up.

CONCLUSION

This study suggests that perforation associated with EMR and ESD does not lead to peritoneal dissemination even in the long term.

Clinical outcome after endoscopic mucosal resection for esophageal squamous cell carcinoma invading the muscularis mucosae--a multicenter retrospective cohort study

BACKGROUND AND STUDY AIMS

Endoscopic mucosal resection (EMR) is now commonly indicated for esophageal squamous cell carcinoma (ESCC) within the lamina propria mucosa. However, EMR for ESCC that has invaded the muscularis mucosa is controversial because the risk of lymph node metastasis is not negligible. We conducted a multicenter retrospective cohort study to investigate the incidence of lymph node metastasis and survival after EMR for ESCC invading the muscularis mucosa.

PATIENTS AND METHODS

A total of 104 patients with 111 lesions invading the muscularis mucosa, were retrospectively studied at eight institutes. No patients exhibited evidence of metastasis of lymph nodes or distant organs prior to EMR. Overall and cause-specific survival rates were calculated from the date of EMR to the date of death or the most recent follow-up visit. Survival curves were plotted according to the Kaplan-Meier method.

RESULTS

In total, 86 patients (82.7%) who did not receive further treatment such as chemotherapy, irradiation therapy, chemoradiotherapy, or esophagectomy after EMR were followed up. Only two patients (1.9%) developed lymph node metastasis after EMR. With a median follow-up period of 43 months (range, 8-134 months), overall and cause-specific survival rates at 5 years after EMR were 79.5% and 95.0%, respectively.

CONCLUSIONS

EMR for ESCC that invades the muscularis mucosa has curative potential as a minimally invasive treatment option.

Analysis of nonlinear relation for skin hemoglobin imaging

This paper discusses the accuracy of the optical determination of the oxygenated and deoxygenated hemoglobin content of human skin under the influence of a melanin layer for a multi-wavelengths imager. The relation between the nonlinear results by Monte Carlo simulation (MCS) and the modified Lambert Beer's law (MLB) is also clarified, emphasizing the importance of the absolute values of skin pigments and their influence on the mean path-length used in MLB. The fitting procedure of the MCS data to the actual skin spectra is shown to obtain the absolute values. It is also shown that once the proper mean path-lengths have been determined, MLB can be used fairly well within an accuracy of 80% compared with MCS. Images of oxygenated hemoglobin with a newly-developed fourwavelength camera are presented to demonstrate the advantages of a multiwavelength system.

Variation of temporal characteristics in human cerebral hemodynamic responses to electric median nerve stimulation: a near-infrared spectroscopic study

Using near-infrared spectroscopy, we studied cerebral hemodynamic responses to electric median nerve stimulation in ten subjects. The recordings were conducted by optical fibers placed over the left scalp. Electric stimuli were delivered to contra- and ipsilateral median nerves, respectively. Hemodynamic responses in the secondary somatosensory cortex were observed following each median nerve stimulation, except for three drowsy subjects. The contralateral stimulation tended to induce a larger response. The degree of change in oxygenated hemoglobin was hardly related to stimulus intensities, and was augmented by attention. Four subjects showed long-lasting responses throughout the stimulus periods, while three other subjects revealed transient responses. Thus, taking account of the temporal activation patterns is necessary for proper interpretation of the hemodynamic response following electric nerve stimulation.

Endoscopically demonstrable esophageal changes after Helicobacter pylori eradication in patients with gastric disease

BACKGROUND AND AIMS

An increased prevalence of reflux esophagitis has been reported following Helicobacter pylori (H. pylori) eradication in patients with duodenal ulcers in Western countries. However, it has remained unknown whether this might also appertain to individuals with other diseases. We therefore carried out this study to determine the effect of eradicating H. pylori infection in a series of Japanese patients.

METHODS

Of a total of 203 H. pylori-positive patients successfully cured of infection, 82 cases (58 males, 24 females) with gastric disease, but not duodenal ulcers, were included in the present study; median age 56 years (range 18-80) and median follow up of 24 months (range 6-65). The patients were investigated clinically and endoscopically at regular intervals.

RESULTS

Mild reflux esophagitis developed after eradication in three of 55 (5.5%) patients formerly without this condition, while it improved after eradication in five of 27 (18.5%) patients, with the disease endoscopically diagnosed prior to eradication. The estimated incidence of esophagitis within 3 years was 4.8% after cure of infection. Short segment Barrett's esophagus developed after eradication in six of 58 (10.3%) patients who did not have it prior to the therapy, while the condition did not improve in 24 patients affected before eradication.

CONCLUSIONS

Endoscopic esophageal changes after H. pylori eradication in the present series of Japanese patients were relatively infrequent and mild. This therapeutic approach thus appears to be safe and unproblematic.

Cortical mapping of gait in humans: a near-infrared spectroscopic topography study

While we have a fair understanding of how and where forelimb-hand manipulative movements are controlled by the neocortex, due to functional imaging studies, we know little about the control of bipedal movements such as walking because of technical difficulties. We succeeded in visualizing cortical activation patterns of human gait by measuring relative changes in local hemoglobin oxygenation using a recently developed near-infrared spectroscopic (NIRS) topography technique. Walking activities were bilaterally associated with increased levels of oxygenated and total hemoglobin in the medial primary sensorimotor cortices and the supplementary motor areas. Alternating foot movements activated similar but less broad regions. Gait imagery increased activities caudally located in the supplementary motor areas. These findings provide new insight into cortical control of human locomotion. NIRS topography might be also useful for evaluating cerebral activation patterns during pathological gait and rehabilitative intervention.

Hremx, the ascidian homologue of ems/emx, is expressed in the anterior and posterior-lateral epidermis but not in the central nervous system during embryogenesis

Recent comparative studies on expression patterns of homeobox genes in the development between ascidians and vertebrates have come to suggest a possibility that a common basic mechanism may exist in the patterning of the central nervous system (CNS). The ems/emx genes have been demonstrated to be involved in the formation and patterning of the anterior CNS in Drosophila and vertebrate embryos. In the present study, we have isolated and analyzed expression of Hremx, the ascidian homologue of ems/emx with particular attention to whether it is expressed in the larval ascidian CNS. Expression of Hremx was detected in the anterior trunk and lateral tail epidermis but not in the anterior CNS. The two expression domains of the epidermis responded in different ways upon treatment with retinoic acid: the anterior expression domain was unaltered, while the posterior expression domain extended to the anterior. The present result suggests that Hremx may have a function in anterior patterning but not in the patterning of the CNS in the ascidian embryo. We suggest the possibility that the function of ems/emx genes in the patterning of the anterior CNS in Drosophila and vertebrate embryos might have been acquired independently in the lineages to Drosophila and vertebrates.

[Treatment of gastric MALT lymphoma by H. pylori eradication]

Strong evidence exists for the efficacy of H. pylori eradication in achieving gastric low-grade MALT lymphoma (L-MALT) regression when the bacteria present. Besides histological evaluation, the appearance of endoscopic finding such as 'discolored mucosa-like atrophy' after treatment may be useful for the prediction of its outcome (endoscopic evaluation). However, a reliable marker for molecular evaluation is not obtained so far. On the other hand, long-term control of L-MALT with H. pylori eradication therapy is uncertain and there still remains a subset of patients with no evidence of H. pylori or who fail H. pylori eradication therapy. Therefore, the optimal non antibiotic therapy for these patients has been studied. According to the recent report, radiation therapy appears to be well tolerated and effective for patients with gastric L-MALT.

Early gastric cancer: endoscopic mucosal resection

In Japan, endoscopic mucosal resection (EMR) is now accepted as a treatment option for cases of early gastric cancer (EGC) with minimum probability of associated lymph node metastasis. In National Cancer Center Hospital (NCCH), EMR is currently applied to patients with early cancers up to 30 mm diameter that were of intestinal type, and were superficially elevated and/or depressed (Type I, IIa and IIc) but without ulceration or definite signs of submucosal invasion. Four hundred seventy nine lesions of EGC in 449 patients were treated by EMR from 1987 through 1998. Submucosal invasion was found on subsequent pathologic examination in 74 lesions, and surgery was recommended. Sixty nine percent of intramucosal cancer was resected with a clear margin, which was therefore judged to be a "complete resection". Local recurrence in the stomach occurred in 2% (5 lesions) with complete resection and in 17% (18 lesions) without complete resection treated conservatively or endoscopically, and all were subsequently treated with curative intent. There were no gastric cancer-related deaths for a median follow-up period of 38 months (3-120 months). Bleeding and perforation were two major complications in EMR, but there were no treatment-related deaths. We believe that EMR allows us to perform less-invasive treatment without sacrificing the possibility of cure. We hope to promote its use around the world.

Anterior vertebral screw strain with and without solid interspace support

STUDY DESIGN

This in vitro biomechanical study examines segmental anterior vertebral screw strain and solid rod construct stiffness with and without the addition of multilevel, threaded cortical bone dowels in a bovine model.

OBJECTIVE

To determine whether strain at the bone-screw interface is higher at the end levels during physiologic range loading, and whether solid interspace support decreases segmental strain on the implant.

SUMMARY OF BACKGROUND DATA

Anterior instrumentation provides greater correction and preserves distal motion segments. However, nonunion and implant failure are observed more frequently than with posterior segmental instrumentation, and when observed, loss of fixation occurs at the end levels.

METHODS

Eight calf spines underwent mechanical testing in the following sequence: 1) intact condition, 2) anterior release with anterior solid rod and bicortical rib grafts, and 3) anterior release with anterior solid rod and threaded cortical bone dowels (L2-L5). Instrumented vertebral screws were used to assess strain within the vertebral body by the near cortex, whereas an anterior extensometer spanning the instrumented segments was used to measure segmental displacements to calculate construct stiffness. The protocol included axial compression (-400 N), right lateral bending (4 Nm (Newton-meter), away from the implant), and left lateral bending (4 Nm, toward the implant). Statistical analysis included a one-way analysis of variance and a Student-Newman-Keuls post hoc test. A pilot study was performed using four additional specimens loaded for 4000 cycles to investigate macroscopic loosening after fatigue loading.

RESULTS

In lateral bending toward the implant, the strain was higher at both end levels, with no differences between the rib and dowel reconstructions. The stiffness values were greater than the intact values for both groups. In lateral bending away from the implant, the strain also was higher at both end screws, and the dowel group had less strain at these levels than the rib group. Both groups were stiffer than the intact condition, and the dowel group was stiffer than the rib group. Axial compressive strain also was higher at the end levels, but this difference did not reach statistical significance. The rib group did not reach intact stiffness values, whereas the dowel group was stiffer than the intact condition. The fatigue study showed gross loosening at one or both end levels in all cases.

CONCLUSIONS

Higher strain was observed at the bone-screw interface in both end screws of an anterior solid rod construct during lateral bending, which correlates with the clinically observed failure location. This suggests that physiologic range loading may predispose to failure at the end levels. Disc space augmentation with solid implants increased construct stiffness in all three load paths and decreased strain at the end levels in lateral bending away from the implant. Future implant modifications should achieve better fixation at the end screws, and the current model provides a means to compare different strategies to decrease strain at these levels.

Biomechanical properties of anterior thoracolumbar multisegmental fixation: an analysis of construct stiffness and screw-rod strain

STUDY DESIGN

Three types of anterior thoracolumbar multisegmental fixation were biomechanically compared in construct stiffness and rod-screw strain.

OBJECTIVES

To investigate the effects of rod diameter and rod number on construct stiffness and rod-screw strain in anterior thoracolumbar multisegmental instrumentation.

SUMMARY OF BACKGROUND DATA

No studies have been undertaken to investigate the biomechanical effects of rod diameter and rod number in thoracolumbar anterior instrumentation.

METHODS

Ten fresh-frozen calf spines (T13-L5) were used. After intact analysis, a total discectomy and transection of the ALL and PLL were performed at L1-L2, L2-L3, and L3-L4 with intervertebral reconstruction using carbon fiber cages. Three types of anterior fixation were then performed at L1-L4: 1) 4.75-mm diameter single-rod, 2) 4.75-mm dual-rod, and 3) 6.35-mm single-rod systems. Single screws at each vertebra were used for single-rod and two screws for dual-rod fixation. These systems share the same basic design except rod diameter. Nondestructive biomechanical testing was performed and included compression, torsion, flexion-extension, and lateral bending. Construct stiffness and rod-screw strain of the three reconstructions were compared.

RESULTS

The 6.35-mm single-rod fixation significantly improved construct stiffness compared with the 4.75-mm single rod fixation only under torsion (P < 0.05). The 4. 75-mm dual rod construct resulted in significantly higher stiffness than did both single-rod fixations (P < 0.05), except under compression. No statistical differences were observed in rod-screw strain between the two types of single rods, whereas dual-rod reconstruction exhibited less rod-screw strain (P < 0.05).

CONCLUSIONS

For single-rod fixation, increased rod diameter neither markedly improved construct stiffness nor affected rod-screw strain, indicating the limitations of a single-rod system. In thoracolumbar anterior multisegmental instrumentation, the dual-rod fixation provides higher construct stiffness and less rod-screw strain compared with single-rod fixation.

The effect of kyphosis on the mechanical strength of a long-segment posterior construct using a synthetic model

STUDY DESIGN

This experimental study used synthetic spine models to compare the effect of the angle of kyphosis, rod diameter, and hook number on the biomechanical stiffness of a long-segment posterior spinal construct.

OBJECTIVE

To examine the biomechanical effects of incremental kyphosis on variously instrumented long-segment posterior spinal constructs.

SUMMARY OF BACKGROUND DATA

Euler's formula for loading of curved long columns would suggest that kyphosis has a profound impact on the biomechanical behavior of long-segment posterior spinal constructs. The effects of sagittal contour on the mechanical properties of long-segment posterior spinal constructs have not been well documented.

METHODS

Kyphotic and straight synthetic spine models were used to test long-segment posterior instrumentation constructs biomechanically while varying rod diameter and the number of hook sites. The synthetic spines, composed of polypropylene vertebral blocks and isoprene elastomer intervertebral spacers, were fabricated with either 0 degrees, 27 degrees, or 53 degrees of sagittal contour. The models were instrumented with 5.5- or 6.35-mm titanium rods, and with either 8 or 12 hooks. The models were loaded from 0 to 300 N in a cyclical ramp fashion using an MTS 858 Bionix testing device testing device. Construct stiffness (force and displacement) during axial compression was determined.

RESULTS

Straight model: Changing the hook number from 8 to 12 caused a 32% increase in construct stiffness with the 5.5-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 36% increase in construct stiffness with the 8-hook pattern. Changing both the rods and hooks caused the stiffness to increase 44%. 27 degrees

MODEL

Changing the hook number from 8 to 12 caused a 20% increase in construct stiffness with the 6.5-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 29% increase in construct stiffness with the 12-hook pattern. Changing both the rods and hooks caused the construct stiffness to increase 26%. 53 degrees

MODEL

Changing the hook number from 8 to 12 caused a 14% increase in construct stiffness with the 6.35-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 17% (P<0.0005) increase in construct stiffness with the 12-hookpattern. Changing both rods and hooks caused the stiffness to increase 21%. Summary data on angular kyphosis: Using the same rod diameter and the same number of hooks, and progressing from a straight alignment to 27 degrees of sagittal contour decreased construct stiffness 32%. Going from straight alignment to 53 degrees decreased the stiffness 59.6%. All reported values were statistically significant (P < 0.0005).

CONCLUSIONS

The biomechanical stiffness of the straight spine was sensitive to both an increase in hook fixation sites and an increase in rod diameter. The kyphotic spines, however, were more sensitive to variations in rod diameter. Although with increasing kyphosis, the optimum instrumentation strategy will maximize both rod diameter and the number of hook sites, instrumented kyphotic spines remain biomechanically "disadvantaged" as compared with nonkyphotic instrumented spines.

Visuospatial imagery is a fruitful strategy for the digit span backward task: a study with near-infrared optical tomography

Our newly developed 64-channel time-resolved optical tomographic imaging system using near-infrared light enables us to obtain a quantitative image of hemoglobin concentration changes associated with neuronal activation in the human brain ¿H. Eda, I. Oda, Y. Ito, Y. Wada, Y. Oikawa, Y. Tsunazawa, M. Takada, Y. Tsuchiya, Y. Yamashita, M. Oda, A. Sassaroll, Y. Yamada, M. Tamura, Multi-channel time-resolved optical tomographic imaging system, Rev. Sci. Instrum., 70 (1999) 3595-3602. Here, we used this optical imaging system to demonstrate that the backward digit span (DB) task activated the dorsolateral prefrontal cortex (DLPFC) of each hemisphere more than the forward digit span (DF) task in healthy adult volunteers, and higher performance of the DB task was closely related to the activation of the right DLPFC. These results suggest that visuospatial imagery is a useful strategy for the DB task. Optical tomography described here is a new modality of neuropsychological studies.

The biomechanical significance of anterior column support in a simulated single-level spinal fusion

This study examines the biomechanical effects of interbody cages and variations in posterior rod diameter in a simulated single-level spinal fusion. A single-level spinal fusion model composed of polyethylene cylinders, posterior pedicular instrumentation, and variously positioned single or dual interbody cages was used for biomechanical testing. Constructs were tested under compressive flexural load, with measurement of stiffness, rod strain, cage strain, and intracage pressure. A strong linear correlation emerged between the mean construct stiffness and cage positioning within the sagittal plane that was inversely related to posterior rod strain. Two small titanium mesh cages were equivalent to one large cage. In a single-level spine model, the presence of and sagittal position of interbody cages significantly influences overall construct stiffness. Cage strain increased with more anterior positions and was inversely related to rod strain.

Endoscopic and histological reversibility of gastric adenoma after eradication of Helicobacter pylori

Although epidemiological studies strongly suggest an association between Helicobacter pylori infection and gastric carcinogenesis via a multistage process, a causal link between them has not been demonstrated. We evaluated the endoscopic and histological changes of gastric adenoma, which is considered a premalignant condition, after eradication of H. pylori. Thirty-five H. pylori-infected patients with gastric adenoma were treated with triple therapy (lansoprazole 30mg/day, clarithromycin 400mg/day, and amoxicillin 1500 mg/day) for 1 week. Of these 35 patients, 30 (86%) exhibited no H. pylori by culture or histology after the therapy. Of the 30 gastric adenomas, 7 decreased in size endoscopically; three gastric adenomas especially showed apparent remission, although histological cure in these three patients was not apparent. Our results suggest that removal of H. pylori infection may only mask a gastric adenoma endoscopically owing to the change around the gastric mucosa.

Biomechanical evaluation of five different occipito-atlanto-axial fixation techniques

STUDY DESIGN

The stabilizing effects of five different occipitocervical fixations were compared.

OBJECTIVES

To evaluate the construct stability provided by five different occipito-atlanto-axial fixation techniques.

SUMMARY OF BACKGROUND DATA

Few studies have addressed occipitocervical reconstruction stability and no studies to data have investigated anterior-posterior translational stiffness.

METHODS

A total of 21 human cadaveric spines were used. After testing intact spines (CO-C2), a type II dens fracture was created and five different reconstructions were performed: 1) occipital and sublaminar wiring/rectangular rod, 2) occipital screws and C2 lamina claw hooks/rod, 3) occipital screws, foramen magnum screws, and C1-C2 transarticular screws/rod, 4) occipital screws and C1-C2 transarticular screws/Y-plate, and 5) occipital screws and C2 pedicle screws/rod. Biomechanical testing parameters included axial rotation, flexion/extension, lateral bending, and anterior-posterior translation.

RESULTS

Pedicle screw fixation demonstrated the highest stiffness among the five reconstructions (P < 0.05). The two types of transarticular screw methods provided greater stability than hook or wiring reconstructions (P < 0.05). The C2 claw hook technique resulted in greater stability than sublaminar wiring fixation in anterior-posterior translation (P < 0.05). However, the wiring procedure did not significantly increase the stiffness levels beyond the intact condition under anterior-posterior translation and lateral bending (P > 0.05).

DISCUSSION

C2 transpedicular and C1-C2 transarticular screws significantly increased the stabilizing effect compared to sublaminar wiring and lamina hooks. The improved stability afforded by C2 pedicular and C1-C2 transarticular screws offer many potential advantages including a high rate of bony union, early ambulation, and easy nursing care.

CONCLUSION

Occipitocervical reconstruction techniques using C1-C2 transarticular screws or C2 pedicle screws offer biomechanical advantages compared to sublaminar wiring or lamina hooks. Pedicle screw fixation exhibited the highest construct stiffness among the five reconstructions.

Does spinal kyphotic deformity influence the biomechanical characteristics of the adjacent motion segments? An in vivo animal model

STUDY DESIGN

In an in vivo sheep model, the effects of spinal fusion and kyphotic deformity on the neighboring motion segments were analyzed.

OBJECTIVES

To investigate the effects of spinal fusion and kyphotic deformity on the adjacent motion segment.

SUMMARY OF BACKGROUND DATA

The in vivo effects of kyphotic deformity on the neighboring motion segments have not been investigated in any studies.

METHODS

Eighteen sheep were equally randomized into three groups based on surgical procedure: L3-L5 in situ posterolateral fusion (n = 6) L3-L5 kyphotic posterolateral fusion (n = 6), and surgical exposure alone (n = 6). After a 16-week survival period, the adjacent motion segment changes were analyzed radiographically, biomechanically, and histologically.

RESULTS

The kyphosis group showed 5.0 degrees +/- 2.6 degrees and 1.7 degrees +/- 1.8 degrees compensatory hyperlordosis at L2-L3 and L5-L6, respectively, compared with surgical exposure and in situ posterolateral fusion, the kyphotic posterolateral fusion significantly influenced cranial adjacent motion segment biomechanics by inducing more stiffness in the posterior ligamentous complex (P < 0.05) and increasing lamina strain under flexion-extension loading (P < 0.05). Results of histologic analysis showed significant degenerative changes of the L2-L3 facet joints in the kyphosis group.

CONCLUSIONS

It is inferred that in the kyphosis group, compensatory hyperlordosis at the cranial adjacent level leads to lordotic contracture of the posterior ligamentous complex. The increased lamina strain, exhibited by the in situ group under flexion-extension, was further increased in the kyphosis group, indicating higher load transmission through the posterior column. Significant degenerative changes of the cephalad adjacent facet joints observed in the kyphosis group served to corroborate the biomechanical data. These results indicate that a kyphotic deformity may lead to facet joint contracture and facet arthritis and may serve as the origin of low back pain at the cranial adjacent level.

The stability of reconstruction methods after thoracolumbar total spondylectomy. An in vitro investigation

STUDY DESIGN

After total spondylectomy, five types of spinal reconstruction techniques were compared biomechanically.

OBJECTIVES

To evaluate the stability provided by five reconstruction methods after total spondylectomy.

SUMMARY OF BACKGROUND DATA

Total spondylectomy presents a worst-case scenario for spinal reconstruction. However, few investigators have biomechanically investigated spinal reconstruction stability after total spondylectomy.

METHODS

Eight human cadaveric spines (T11-L5) were used. After intact analysis, a total spondylectomy was performed at L2 and reconstructed using Harms titanium mesh (Depuy-Motech, Warsaw, IN) as an anterior strut. Anterior, posterior, or circumferential instrumentation techniques were then performed using the Kaneda SR and ISOLA pedicle screw systems (AcroMed Corp., Cleveland, OH) as follows: 1) anterior instrumentation at L1-L3 with multisegmental posterior instrumentation at T12-L4 (AMP), 2) anterior instrumentation at L1-L3 with short posterior instrumentation at L1-L3 (ASP), 3) anterior instrumentation at L1-L3 (A), 4) multilevel posterior instrumentation at T12-L4 (MP), and 5) short posterior instrumentation at L1-L3 (SP). Nondestructive biomechanical testing was performed under axial compression, flexion-extension, and lateral bending loading modes.

RESULTS

Only circumferential instrumentation techniques (AMP, ASP) exhibited higher stiffness than the intact spine in all loading modes (P < 0.05). Short circumferential fixation provided more stability than did multilevel posterior instrumentation (P < 0.05). Multilevel posterior fixation provided more stiffness than did short posterior and anterior instrumentation alone (P < 0.05).

CONCLUSIONS

Only circumferential fixation techniques provide more stability than the intact spine in all testing modes. Short circumferential instrumentation provides more stability than multilevel posterior instrumentation alone and requires fewer levels of spinal fusion.

Biomechanical role of the intervertebral disc and costovertebral joint in stability of the thoracic spine. A canine model study

STUDY DESIGN

Biomechanical evaluation was performed to investigate the stability of the thoracic spine. Unilateral resection of the intervertebral disc, the rib head joint, and the costotransverse joint were sequentially performed, and nondestructive cyclic loading tests were conducted at each injury stage to examine the roles of the intervertebral disc and the costovertebral joint of the thoracic spine. The effects of each resection were three-dimensionally analyzed as the main motion and the associated coupled motions.

OBJECTIVE

To examine the role of the intervertebral disc and the costovertebral joint in stability of the thoracic spine.

SUMMARY OF BACKGROUND DATA

The effects of unilateral resection of the intervertebral disc and the costovertebral joints in the thoracic spine with the rib cage have not been documented three-dimensionally in a biomechanical study.

MATERIALS AND METHODS

Ten canine rib cage-thoracic spine complexes, consisting of the sixth to eighth ribs, the sternum and T5-T8 vertebrae, were used. Six pure moments along three axes, flexion-extension, lateral bending, and axial rotation, were applied to the specimen, and the angular deformation between T6-T7 was recorded by a stereophotogrammetric method. After the intact specimens were tested, staged resections were conducted in the following manner: partial resection of the T6-T7 intervertebral disc, performed as a resection of the anterior longitudinal ligament, the nucleus pulposus, and the annulus fibrosus on the approach side, leaving the posterior longitudinal ligament intact; resection of the right seventh rib head with the joint capsule; and resection of the right seventh costotransverse joint. At each stage, the main motion and associated coupled motions were determined three dimensionally.

RESULTS

The ranges of motion (ROM) in flexion-extension, lateral bending, and axial rotation were significantly increased after partial discectomy (P < 0.01). Moreover, along with large increases in the ROM of the main motions in left axial rotation and right lateral bending, coupled motions, expressed by right lateral bending and left axial rotation, showed marked increases after resection of the rib head joint (P < 0.05). The neutral zones also increased in lateral bending, axial rotation, and flexion-extension after partial discectomy (P < 0.01). A further increase in the neutral zone was observed in lateral bending after resection of the right seventh rib head (P < 0.01).

CONCLUSIONS

In this canine spine model, the intervertebral disc regulates the stability of the thoracic spine in flexion-extension, lateral bending, and axial rotation. Moreover, the articulation of the rib head with the vertebral bodies provides stability to the thoracic spine in lateral bending and axial rotation. Unilateral resection of the rib head joint after partial discectomy on the same side produces significant coupled motions in lateral bending and axial rotation, resulting in a significant decrease in thoracic spinal stability, and integrity.

Effects of chondroitinase ABC and chymopapain on spinal motion segment biomechanics. An in vivo biomechanical, radiologic, and histologic canine study

STUDY DESIGN

The biomechanical effects of chondroitinase ABC and chymopapain related to spinal segmental instability were investigated using a canine model, as well by as radiologic and histologic analyses.

OBJECTIVES

To evaluate the biomechanical, radiologic, and histologic affects on the lumber intervertebral disc of chondroitinase ABC compared with chymopapain.

SUMMARY OF BACKGROUND DATA

No study on the biomechanical effects of chondroitinase ABC has been reported.

METHODS

Forty-eight lumbar intervertebral discs in eight beagles were randomly assigned to three groups and received one of three materials: chondroitinase ABC, chymopapain, or buffered saline, using a lateral percutaneous procedure. One week after injection, the animals were killed and the lumbar spinal motion segments were removed. Spinal segmental instability after chemonucleolysis was evaluated in spinal motion segments without posterior elements. Radiologic and histologic changes were also investigated.

RESULTS

Spinal segmental instability and disc space narrowing were more greater in the chymopapain group than in the chondroitinase ABC group. Destruction of nucleus and anulus proteoglycans, indicated by loss of safranin-O staining, was less intense in chondroitinase ABC-injected discs.

CONCLUSIONS

Chondroitinase ABC results in less spinal segmental instability, disc space narrowing, and destruction of proteoglycans in intervertebral disc matrix than chymopapain.

Biomechanical role of the posterior elements, costovertebral joints, and rib cage in the stability of the thoracic spine

STUDY DESIGN

This is a biomechanical study of the thoracic spine. Various ligaments and joints were resected sequentially and nondestructive cyclic loading tests were performed. Effects of each resection were analyzed biomechanically.

OBJECTIVES

To investigate the role of the posterior elements, costovertebral joints, and rib cage in the stability of the thoracic spine.

SUMMARY OF BACKGROUND DATA

There have been no experimental studies concerning the mechanical interaction between the thoracic spine and rib cage.

METHODS

Eight canine rib cage-thoracic spine complexes, consisting of the sixth to eighth ribs, sternum, and T5-T9 vertebrae, were used. Six pure moments along three axes were applied to the specimens, and angular deformation of T6-T7 was recorded. After testing the intact specimen, resection of the stabilizers was conducted incrementally in the following manner: 1) removal of the posterior elements at T6-T7, 2) resection of the bilateral seventh costovertebral joints, and finally, 3) destruction of the rib cage. The same loading tests were repeated at each stage. The ranges of motion and neutral zones were calculated by digitization.

RESULTS

A large increase in the range of motion in flexion-extension was observed after resection of the posterior elements and in lateral bending and axial rotation after resection of the costovertebral joints. A significant increase in the neutral zone in lateral bending and axial rotation was observed after bilateral resection of the costovertebral joints and destruction of the rib cage.

CONCLUSIONS

The costovertebral joints and rib cage play an important role in providing stability to the thoracic spine. The state of the costovertebral joints and rib cage should be assessed to evaluate the stability of the thoracic spine.

Optical tomography by the temporally extrapolated absorbance method

The concept of the temporally extrapolated absorbance method (TEAM) for optical tomography of turbid media has been verified by fundamental experiments and image reconstruction. The TEAM uses the time-resolved spectroscopic data of the reference and object to provide projection data that are processed by conventional backprojection. Optical tomography images of a phantom consisting of axisymmetric double cylinders were experimentally obtained with the TEAM and time-gating and continuous-wave (CW) methods. The reconstructed TEAM images are compared with those obtained with the time-gating and CW methods and are found to have better spatial resolution.