A multi-institutional retrospective study of 340 cases of sinonasal malignant tumor

OBJECTIVE

Sinonasal malignant tumors (SNMT) are relatively rare among head and neck malignant tumors. Most are squamous cell carcinomas, and malignant melanomas, olfactory neuroblastomas, adenoid cystic carcinomas, sarcomas, and others also occur. The most common primary site of nasal sinus squamous cell carcinoma is the maxillary sinus. In recent years, a decrease in incidence of maxillary sinus squamous cell carcinoma (MSSCC) has been reported along with a decrease in the incidence of sinusitis. MSSCC is treated with a combination of surgery, radiation, and chemotherapy. Treatment decisions are made according to the progression of the disease, the patient's general condition, and the patient's own wishes. There are variations in treatment policies among facilities due to the specialty of staff and cooperation with other departments at each facility. We conducted a multi-institutional retrospective study to compare outcomes by treatment strategy.

METHODS

In this study, 340 patients with SNMT who were treated at 13 Hospitals (Head and Neck Oncology Group (Kyoto-HNOG) ) during the 12-year period from January 2006 to December 2017 were included. There were 220 patients with squamous cell carcinoma, 32 with malignant melanoma, 21 with olfactory neuroblastoma, and 67 with other malignancies. Of the squamous cell carcinomas, 164 were of maxillary sinus origin. One hundred and forty cases of MSSCC that were treated radically were included in the detailed statistical analysis.

RESULTS

There were 5 cases of cStage I, 9 cases of cStage II, 36 cases of cStage III, 74 cases of cStage IVa, and 16 cases of cStage IVb. There were 92 cases without clinical lymph node metastasis (cN(-)) and 48 cases with clinical lymph node metastasis(cN(+)). Primary tumors were treated mainly by surgery in 85 cases (Surg) and by radical radiation therapy (with or without chemotherapy) of 6-70 Gy in 55 cases(non-Surg). The 5-year overall/disease-free survival rate (OS/DFS) for MSSCC was 65.1%/51.6%. Old age, renal dysfunction, and clinical T progression were independent risk factors for OS, and renal dysfunction was an independent risk factor for DFS. In cN(-) patients, OS and DFS were significantly better in Surg group than in non-Surg group. In cN(+) patients, there was no significant difference in OS and DFS between Surg and non-Surg groups.

CONCLUSION

For patients with MSSCC without lymph node metastasis, aggressive surgery on the primary tumor contributes to improved prognosis.

Mucosal melanoma of the head and neck: a retrospective analysis of 34 cases in Japan

PURPOSE

Mucosal melanoma of the head and neck (MMHN) is a rare condition. This study aimed to investigate oncological outcomes of surgical intervention in patients with MMHN.

MATERIALS AND METHODS

The study included 34 patients with MMHN who underwent surgical resection as initial treatment at 10 institutions in Japan between July 2005 and June 2015. Results: The 5-year overall survival (OS), local control rate (LCR), disease-free survival (DFS), and disease-specific survival (DSS) rates were 48.7%, 53.4%, 32.4%, and 55.1%, respectively. Based on multivariate analysis, no independent prognostic factors for the 5-year OS and DSS were found. Based on univariate analysis, the 5-year LCR was worse in patients with lesions in the nasal cavity and paranasal sinuses than in the oral cavity and pharynx. However, no differences in oncological outcomes were identified in relation to primary sites, and postoperative radiotherapy (PORT) and adjuvant systemic therapy did not contribute to improvements in the 5-year OS.

CONCLUSIONS

No independent prognostic factors for the 5-year OS or DSS were identified. Regional or distant recurrences are often identified, regardless of local control with surgical resection. Difficult control of MMHN with conventional therapeutic strategies, such as surgical intervention, PORT, and systemic therapy, has been suggested.

Characteristics of oral squamous cell carcinoma focusing on cases unaffected by smoking and drinking: A multicenter retrospective study

BACKGROUND

Some oral squamous cell carcinoma (OSCC) cases are unaffected by smoking or drinking. This study aimed to clarify distinctive groups among OSCC patients and examine the characteristics of multiple primary carcinomas (MPCs).

METHODS

We analyzed data from 970 patients. The patients were divided into three groups: all individuals <45 years (<45 y), smokers/drinkers ≥45 years (SD ≥45 y), and non-smokers/non-drinkers ≥45 years (NSND ≥45 y).

RESULTS

Tongue cancers were more common in the <45 y group than in the other groups (p < 0.001). The NSND ≥45 y group was significantly older and more likely to be female than the SD ≥45 y group (p < 0.001). MPCs in the upper aerodigestive tract were more common in men and smokers/drinkers, whereas women were at risk for multiple primary OSCCs (p = 0.022).

CONCLUSIONS

The "young tongue" and "elderly female" subgroups and characteristics of MPCs suggest carcinogenic factors of OSCC other than smoking and drinking.

Clinicopathological Characteristics and Survival Outcomes of Patients with Buccal Squamous Cell Carcinoma: Results of a Multi-Institutional Study

Background and Objectives: To investigate clinicopathological characteristics and survival outcomes of patients with buccal cancer in Japan. Materials and Methods: This study was conducted using a database of 1055 patients with oral cancers treated between 2010 and 2017 at 12 institutions in Japan. Ninety-two patients (8.7%) with primary buccal cancer were extracted and clinicopathological characteristics and survival outcomes were compared between patients with buccal cancers and patients with other oral cancers. Results: Ages were significantly higher in the patients with buccal cancer (73 years old vs. 69 years old). Buccal cancer had less advanced cT stage and cN stage than other oral cancers. Overall 5-year survival (OS) was 80.6%, and recurrence-free 5-year survival (RFS) of buccal cancers was 67.8%, and there were no significant differences in survival compared with other oral cancers in terms OS or RFS (5y-OS: 82.5%, 5y-RFS: 74.4%). However, patients with stage IV buccal cancer showed poorer prognosis in terms of OS and RFS compared with the same stage patients with other oral cancer. Advanced T stage was the only factor independently associated with both OS and RFS of patients with buccal cancer in this study. Conclusions: Postoperative radiotherapy or chemoradiotherapy should be considered to improve survival outcome of buccal cancer patients, especially for the patients with advanced primary site disease or a higher cancer stage.

A retrospective multicenter study of sublingual gland carcinoma in Japan

OBJECTIVE

Salivary gland carcinoma is rare among head and neck cancers. Sublingual gland carcinoma, a type of salivary gland carcinoma, is even rarer; therefore, the number of cases at a single institute is too small for sufficient evaluation of tumor characteristics. We conducted a multicenter, retrospective analysis of sublingual gland carcinomas in patients who visited 12 institutions associated with the Kyoto Hospital and Affiliated Facilities Head and Neck Clinical Oncology Group.

METHODS

Thirteen previously untreated patients who visited the institutions between 2006 and 2015 were enrolled. The overall survival (OS) and disease-free survival (DFS) rates for all patients and by disease stage were analyzed. Statistical analyses were performed for all patients with respect to disease stage.

RESULTS

Eight of thirteen patients were diagnosed with adenoid cystic carcinoma on pathological study. A significant difference in OS rate was observed between patients with Stage I-III and Stage IV disease; however, the difference in DFS rate by disease stage was not significant.

CONCLUSION

Stage IV disease was identified as a poor prognostic factor in patients with sublingual gland carcinoma. However, even patients with Stage I-III disease experienced relatively short DFS. Distant metastasis is a serious problem among patients with sublingual gland carcinoma.

Unknown primary squamous cell carcinoma of the head and neck: retrospective analysis of 80 cases

OBJECTIVES

The management of patients with cervical metastasis in head and neck cancer of unknown primary (HNCUP) remains controversial. This current multicenter retrospective study investigated the treatment outcomes of patients with HNCUP.

METHODS

The study included patients who were treated curatively at 12 institutions in Japan from January 2006 to December 2015.

RESULTS

Eighty patients with HNCUP were included. The median follow-up period was 34 months. The three-year overall survival (OS), disease-specific survival (DSS), regional relapse-free survival (RRFS), local progression-free survival (LPFS), and distant metastasis-free survival (DMFS) rates were 72.5%, 80.3%, 74.0%, 89.7%, and 86.9%, respectively. Nodal status was a significant factor for OS, DSS, RRFS, and DMFS; and extracapsular extension (ECE) was significant for OS and DSS. There was a distinct difference between the survival rates of patients with N1-2a and N2b-3 disease. RT was a significant positive factor for LPFS (3-year LPFS, RT 93.0% vs. no RT 83.0%, p = .043).

CONCLUSIONS

For N2a as well as N1 disease without ECE, a single treatment modality, including ND or RT alone is acceptable. When ND alone is performed, thorough monitoring should be continued during follow-up to identify the emergence of the primary lesion.

Survival in patients with parotid gland carcinoma - Results of a multi-center study

BACKGROUND

Parotid gland carcinoma is a rare malignancy, comprising only 1-4% of head and neck carcinomas; therefore, it is difficult for a single institution to perform meaningful analysis on its clinical characteristics. The aim of this study was to update the clinical knowledge of this rare disease by a multi-center approach.

METHODS

The study was conducted by the Kyoto University Hospital and Affiliated Facilities Head and Neck Clinical Oncology Group (Kyoto-HNOG). A total of 195 patients with parotid gland carcinoma who had been surgically treated with curative intent between 2006 and 2015 were retrospectively reviewed. Clinical results including overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), local control rate (LCR), regional control rate (RCR), and distant metastasis-free survival (DMFS) were estimated. Univariate and multivariate analyses were performed to identify prognostic factors.

RESULTS

The median patient age was 63years old (range 9-93years), and the median observation period was 39months. The OS, DFS, DSS, LCR, RCR, and DMFS at 3years were 85%, 74%, 89%, 92%, 88%, and 87%, respectively. Univariate analysis showed age over 74, T4, N+, preoperative facial palsy, high grade histology, perineural invasion, and vascular invasion were associated with poor OS. N+ and high grade histology were independent factors in multivariate analysis. In subgroup analysis, postoperative radiotherapy was associated with better OS in high risk patients.

CONCLUSION

Nodal metastases and high grade histology are important negative prognostic factors for OS. Postoperative radiotherapy is recommended in patients with advanced high grade carcinoma.

Adenoid cystic carcinoma of the head and neck: a retrospective multicenter study

BACKGROUND

Adenoid cystic carcinoma of the head and neck (ACCHN) is rare and difficult to study effective treatment at one institute. Our aim is to identify prognostic factors for this disease by conducting a multicenter study at 11 institutions in Japan.

METHODS

A retrospective multicenter study of ACCHN was performed. One hundred and three patients were identified between 2006 and 2015. The overall survival (OS) rate for all patients was calculated, and OS, locoregional control (LRC) rate, or no distant metastasis (NDM) rate was calculated for patients in that the surgery was performed without distant metastasis (DM). Statistical analyses were performed.

RESULTS

A significant difference with multivariate analysis was observed in patients in sublingual glands, stage IV and the use of radiation therapy ≥60Gy (sufficient RT) in OS for all patients. A significant difference was observed in the use of sufficient postoperative RT in the OS and the LRC rate, and in pathological surgical margins in the NDM rate.

CONCLUSION

Sublingual glands or stage IV was a poorer, and sufficient RT was a better prognostic factor for ACCHN. Sufficient RT was effective to prevent local recurrence after surgical resection. Positive surgical margins caused an increase in DM.

Diagnostic accuracy of lateral neck radiography in ruling out supraglottitis: a prospective observational study

OBJECTIVE

To assess the diagnostic accuracy of lateral neck radiographs (LNR) for acute supraglottitis in adults.

DESIGN

A single centre prospective observational study.

SETTING

Emergency department at Kurashiki Central Hospital, Japan.

PARTICIPANTS

Adult patients who underwent LNR to detect supraglottitis.

MAIN OUTCOME MEASURES

Presence of supraglottitis, based on nasopharyngeal laryngoscopy or a follow-up telephone call, 7-30 days after the visit.

RESULTS

140 patients had LNR during the study period. 35 patients were excluded from further analysis because of lack of consent. Of the 105 eligible patients, 21 patients (20%) were given the diagnosis of supraglottitis: 17 of 29 with a radiographic abnormality, and 4 of 76 patients without a radiographic abnormality. Three of the four cases where LNR was negative was grade 1, and all cases of grade 3 or higher had abnormal LNR. Sensitivity and specificity (95% CI) of LNR for supraglottitis were 81.0% (64.2 to 97.7) and 85.7% (78.2 to 93.2), respectively. The positive predictive value of LNR was 58.6% (40.7 to 76.5) and the negative predictive value was 94.7% (89.7 to 99.8). The positive likelihood ratio of LNR was 5.67 (3.27 to 9.82) and the negative likelihood ratio was 0.22 (0.10 to 0.51).

CONCLUSIONS

LNR showed only moderate sensitivity and specificity for supraglottitis and would miss some cases of supraglottitis if the pre-test probability is high. LNR was very sensitive for grade 3 or higher supraglottitis, but would miss milder cases.

TRIAL REGISTRATION

UMIN000011928.

[A review of the complications and candida colonization associated with voice rehabilitation using a voice prosthesis]

Between December 2004 and December 2011, we have used the indwelling voice prosthesis for voice rehabilitation in 28 patients after total laryngectomy in our department. To clarify both the complications and safety of voice reconstruction using a voice prosthesis, and the occurrence of candida colonization, we conducted a retrospective study with a review of the Japanese literature. Twenty-six patients who were observed over a period of more than six months at our hospital were enrolled in this study. We examined the interval of prosthesis replacement, types and frequency of complications, candida colonization, and clinical outcomes. The median follow-up time postoperatively was 28.8 months (range 8.1-95.7). The average interval of prosthesis replacement was 147 days (4.9 months). Complications occurred in 14 patients (54%), and 6 patients (23%) of whom were hospitalized. The main complications were periprosthetic leakage, increased granulation around the tracheoesophageal shunt and stenosis of the trachea stoma. There were no significant differences in the frequency of complications in the background factor of the patients as far as age (p = 0.495), radiation therapy (p = 0.686) or reconstruction time (p = 0.257) were concerned. Candida species was detected in 81% of the specimens which we submitted to a culture test and confirmed the pseudohyphae which comfirmed the pathogenicity from the histopathological examination. Moreover, radiation therapy was significantly associated with the detection of candida (p = 0.004). Permanent closure of the tracheoesophageal shunt for periprosthetic leakage was required in one patient, but we were able to deal with the other complications. No patient experienced any life-threatening complications and all are safely using the prostheses. It has been reported that complications will occur over the long-term, thus careful follow-up is necessary.

PMDA's challenge to accelerate clinical development and review of new drugs in Japan

In recent years, Japan's Pharmaceuticals and Medical Devices Agency (PMDA) has conducted several projects to shorten drug development and review times in Japan to resolve the "drug lag." Key to achieving this goal is greater involvement by the PMDA in drug development through enhancement of scientific consultation and improvement of the review process by reinforcing the operational system, including hiring more reviewers. We discuss here the current projects of the PMDA as well as future challenges.

A case of severe low back pain associated with Richard disease (lumbosacral transitional vertebra)

The imaging findings in some cases of low back pain are difficult to describe and the pathophysiology is not clear because subjective findings are usually difficult to document. This report concerns a rare case about the lumbosacral joint causing persistent severe back pain which in itself does not usually have any pathological meaning. We describe the diagnosis, treatment, and outcome of a patient suffering from low back pain with lumbosacral transitional vertebra. The radiological examination showed the congenitally malformed transverse processes of the 5th lumbar vertebra to create a facet joint-like shape at the sacral ala region on both sides. Surgery resulted in immediate disappearance of the low back pain. When the lumbosacral junction shows some instability without fusion, the joint-like region could be the cause of low back pain. The lumbosacral transitional vertebra may be associated with low back pain. Electric denervation of the space between the transverse process of 5th lumbar vertebra and sacral ala is minimally invasive and effective for pain eradication.

Cervical vertigo after hair shampoo treatment at a hairdressing salon: a case report

STUDY DESIGN

A case report of cervical vertigo that occurred after shampoo treatment in a hairdressing salon. Abnormalities were detected on magnetic resonance images and magnetic resonance angiography scans.

OBJECTIVES

To describe the diagnosis of cervical vertigo caused by neck hyperextension.

SUMMARY OF BACKGROUND DATA

Neck hyperextension may induce vertigo and dizziness; the pathophysiology remains unclear, however, because subjective findings are usually difficult to document.

METHODS

The diagnosis, treatment, and outcome of a patient with cervical vertigo that occurred after hair shampoo treatment in a hair dressing salon were assessed.

RESULTS

Magnetic resonance angiography demonstrated narrowing of the left vertebral artery, whereas magnetic resonance imaging showed cerebellar infarction. Treatment included rest and drugs that activate cerebral circulation and prevent platelet aggregation. Improvement was noted within few days.

CONCLUSIONS

The authors suggest that the hyperextended neck position during hair shampoo treatment in a beauty parlor may be a risk factor for back lifting or cerebellum vascular insufficiency. Public education should lead to avoidance of this position during hair shampoo treatment at hair dressing salons.

[Evaluation of dissolution behavior for the products containing tegafur and uracil]

Generic drugs are widely used with the object of cost saving in many Japanese therapeutic scenes now. The products containing the same active ingredient(s), even if they are innovative drugs or generic ones, must be designed to possess the equivalent quality. In this report, we observed the dissolution behavior patterns of three generic drugs that contain Tegafur and Uracil, drugs A, B, and C, and compared them with that of an innovative product, UFT. Drugs B and C were similar to UFT in the dissolution rate of Tegafur, but drug A was not. On the dissolution rate of Uracil, all the generic products, drugs A, B and C, did not amount to the level equivalent to that of UFT. Therefore, these generic products did not indicate the same dissolution behavior pattern as UFT. It was suggested that the pharmaceutical technology used in the manufacture was not equivalent even if the products of the same dosage form contain the same kind and content of the active ingredient(s).

Diagnosis of lumbar disc herniation by three-dimensional MRI

The lumbo-sacral region has anatomical lordosis and two-dimensional magnetic resonance imaging (2D-MRI) cannot therefore show spinal roots including the dorsal root ganglions in one picture. This makes it difficult to present the lateral part of spinal root lesions. We have recently described a new three-dimensional magnetic resonance imaging (3D-MRI) method which allows a stereoscopic view of the spinal cord and spinal nerve roots. In the present study, we evaluated three 3D-MRI techniques, rapid imaging spin echo (RISE) small tip angle gradient echo (STAGE), and short TI inversion recovery (STIR), for detecting disc tissue degeneration, and spinal cord and nerve root compression for identification of nerve roots and detecting signal changes indicative of thickening of the nerve root, and for evaluation of the extent of herniation in 30 patients with lumbar disc herniation. The RISE method was superior for detecting signal changes in disc degeneration, (in 100% of patients) compared with the STAGE method (in 56.1% of patients). All methods poorly identified L4 roots compared with L5 or S1 roots. The STIR method was the best for identifying nerve roots (L4, 62.5%; L5, 87. 5%; S1, 91.7%). STAGE and STIR were useful for detecting injuries of the nerve roots. RISE showed disc extrusion better than the other techniques (in 64.7% of patients). The presurgical diagnosis on 3D-MRI agreed with the pathology findings at surgery in 71.4% of STIR, 55.6% of RISE, and 33.3% of STAGE MR images. Our results indicate that 3D-MRI is most useful for the diagnosis of lumbar disc herniation and spinal cord and nerve root compression. The STIR method is best for identifying abnormalities of the spinal cord, roots, and intervertebral discs.

Multiple inhibition of platelet activation by aurintricarboxylic acid prevents vascular stenosis after endothelial injury in hamster carotid artery

Activated platelets are instrumental in restenosis due to their role in thrombus formation. Aurintricarboxylic acid (ATA) has been reported to prevent platelet activation by inhibiting von Willebrand factor binding to platelet glycoprotein (GP)Ib. We investigated the effects of ATA in vitro and in vivo in hamsters. ATA inhibited the in vitro platelet aggregation induced by ADP, botrocetin and thrombin, but not by collagen. The IC50 values during the ex vivo platelet aggregation by ADP, botrocetin and thrombin were 8.2 +/- 1.8 microM, 0.9 +/- 0.4 microg/ml and 2.4 +/- 0.8 unit/ml, respectively. The platelet retention time to collagen-coated beads of hamster blood samples was inhibited by ATA (0.1, 0.3 and 1.0 mg/kg per hour) in a dose-dependent manner. Continuous administration of ATA (0, 0.1, 0.3, 1.0, 3.0 and 10.0 mg/kg per h) via an infusion pump produced dose-dependent antithrombotic effects: the time to occlude the carotid artery after vascular injury with a modified catheter was prolonged. Only when infused at doses of 3.0 and 10.0 mg/kg per hour, bleeding times were significantly prolonged. The continuous treatment with ATA (1.0 mg/kg per h) using a 2ML1 Alzet infusion pump for 2 weeks, resulted in a decrease in neointimal area by 22.2 +/- 6.8% when measured 2 weeks after injury induction. DNA synthesis using DDT1MF2 hamster SMCs was decreased by ATA in a dose-dependent manner. ATA reduced the number of platelets adhering on the injured area, as detected by electron microscopy. These results indicated that treatment with ATA inhibited platelet adhesion but also SMC proliferation. These observations may explain the effect of ATA on neointima formation.

Aluminum accumulation in the skin in end-stage renal failure

Accumulation of aluminum (Al) of the skin of end-stage renal failure (ESRF) patients was analysed by means of an energy dispersive X-ray spectrometer (Kevex 7000 series). The Al detecting ratio was higher in the hemodialysis (HD) groups than in the non-dialysis ESRF group (p less than 0.025) and the normal volunteer group (p less than 0.01). There were no significant differences between the duration of HD (group I and group II), and between the non-dialysis ESRF and the normal volunteer groups. High Al accumulation detected in the skin of the HD groups may be attributed to the dosing of aluminum hydroxide gel (Al-gel), judging from the fact that all cases in the HD groups had been dosed with Al-gel (0.75-4.5 g/day). High Al detections were observed in 2 cases each of the HD and nondialysis ESRF groups responding HBs-antigen positive.

Microangiopathic changes of subepidermal capillaries in end-stage renal failure

Skin biopsies were taken from 63 patients with end-stage renal failure (ESRF) and 5 normal volunteers, 53 of whom were on maintenance hemodialysis (HD) and the other 10 without HD. They were examined with light and electron microscopy and subepidermal capillaries were subjected to image analysis. Thickening of the basement membrane (BM) with multilamination of the basal lamina, endothelial activation and chronic inflammatory cell infiltration with participation of mast cells were evident. The extent of these BM changes was correlated with the duration of HD, but not significantly correlated with the clinical findings indicative of arteriosclerosis. There was significant correlation between the duration of HD and mast cell proliferation or eosinophilia. We suspect that the subepidermal capillary changes represent an inflammatory reaction provoked by uremic toxins or by the repeated use of an artificial organ.

Pruritus and mast cell proliferation of the skin in end stage renal failure

We studied the relationships between dermal mast cell proliferation and pruritus or hyperparathyroidism in hemodialysis (HD). Skin biopsies were taken from 59 patients in end stage renal failure; 51 were on maintenance HD, and the other 8 were not. As a control, 34 non-renal failure pruritic patients were used. Thirty-one of the 59 end stage renal failure patients (52.5%) had pruritus. The incidences of pruritus found in patients on HD and those not on HD were 56.9% and 25%, respectively. Significantly larger numbers of dermal mast cells were found in HD patients than in the control. There was no clear relationship between dermal mast cell proliferation and serum parathyroid hormone (PTH) levels. We speculated that the cause of pruritus in the patients undergoing maintenance HD was due to an increase of dermal mast cells and a release of histamine as a result of extra-corporeal circulation.

[Fundamental and clinical studies on CT gas myelography of the cervical spine]

We applied CT gas myelography at the cervical spinal region and investigated the clinical value of CT gas myelography as a supplementary diagnostic method for the spinal cord and vertebral diseases. Fundamental studies of the conditions of window width and window height and the permitted limit of the angle of incidence were made with phantoms of human neck to establish proper conditions of these factors. In clinical studies, 23 adult persons, who had no abnormality in the cervical spine and in the cervical spinal cord were observed to have normal CT gas myelograms of the cervical region, whereas 37, of clinical cases including 18 of cervical spondylosis, 10 of OPLL, 2 of cervical discopathy, 3 of fracture and dislocation of the cervical spine, 2 of cervical vertebral tumor and 2 of CYL, were found to show clear pathologic findings in the cross sections of the vertebral foramen, subarachnoidal space and spinal cord on the CT gas myelograms. The representative cases of these diseases were presented. The gas myelograms were morphologically classified and investigated in relation to the clinical findings. From the result of these investigations, CT gas myelography appears to be highly useful as a supplementary diagnostic method for diseases of the cervical spine and the cervical spinal cord. Furthermore, we compared the effect of this method with that of CT myelography using metrizamide, a recently developed water-soluble contrast medium.