論文

Study Design. A retrospective case study of patients with intraspinal cyst having a distinct connection with the corresponding intervertebral disc. Objectives. To propose a new clinical entity, "discal cyst," by clarifying the clinical, radiographic, and histologic aspects of the disease. Summary of Background Data. Several types of intraspinal cysts with different pathogenesis, causing symptoms indistinguishable from those of lumbar disc herniation, have been reported, such as perineural cysts, synovial cysts, and ganglion cysts. However, to the authors' knowledge, no detailed analysis has been made of cysts that have a distinct connection with the corresponding intervertebral disc. Methods. Clinical pictures, radiographic findings, and surgical and histologic findings in eight surgically treated patients with intraspinal cyst having a distinct connection with the intervertebral disc were reviewed. Possible pathogenesis and a proposal for nomenclature were also discussed. Results. This disease can be characterized by (1) clinical symptoms indistinguishable from those of typical disc herniation, manifesting as a unilateral single nerve root lesion; (2) incidence at slightly younger age and at upper intervertebral levels than with typical disc herniation; (3) T1 low signal and T2 high signal intensity, round to oval mass lesion on magnetic resonance imaging, compatible with a liquid-containing cyst; (4) minimal degeneration of the involved disc, either on discography/computed tomographic discography or magnetic resonance imaging; (5) a connection between the cyst and the corresponding intervertebral discs on discograms with severe radiating pain in the affected leg at the time of injection; (6) immediate relief of symptoms after simple removal of the cyst; (7) cyst wall consisting of dense fibrous connective tissue containing bloody to clear serous discharge; and (8) absence of disc materials and a specific lining cell layer on histologic examination, Although the exact cause is unknown, underlying minor disc injury may serve as a basis for cyst formation. Conclusion. Eight cases of intraspinal cysts communicating with the intervertebral disc presenting symptoms identical to those of disc herniation are presented. Because all cysts were connected to the corresponding disc and the development of the cyst was assumed to be related to underlying disc injury, it is proposed to name-this clinical entity discal cyst.

Study Design. A retrospective follow-up study of conservatively treated patients with mild cervical myelopathy caused by cervical soft disc herniation. Objective. To investigate the outcome of conservative treatment for patients with mild myelopathy caused by cervical soft disc herniation and to evaluate usefulness of magnetic resonance findings in the prediction of the outcomes. Summary of Background Data. Recent studies on conservative treatment of cervical soft disc herniation have focused mainly on radiculopathy, and not on myelopathy. Methods. Twenty-seven patients with mild cervical myelopathy secondary to cervical soft disc herniation were treated conservatively for more than 6 months by cervical bracing and restriction of daily activities. Of the 27 patients, 17 patients (Group A) underwent conservative treatment only and it was associated with improvement in their neurologic deficits, while the other 10 patients (Group B) ultimately underwent decompression surgery because of neurologic deterioration. Comparisons between the two groups were made in regard to JOA score, patient satisfaction, and magnetic resonance findings, including location of the disc herniation (focal or diffuse in the sagittal plane, median or paramedian in the axial plane). Results. The JOA scores were 13.6 ± 1.6 in Group A and 14.1 ± 1.6 in Group B before treatment, 14.9 ± 1.0 and 12.9 ± 2.1, respectively, at 3 months, and 16.2 ± 0.8 and 16.0 ± 1.2, respectively, at the final follow-up. The JOA scores at 3 months were significantly lower in Group B than in Group A. Satisfaction with the results of treatment at the final follow-up was reported by 77% of the patients in Group A and 90% in Group B. Focal-type herniation was present in 47% of the patients in Group A and 70% in Group B, while median-type herniation was diagnosed in 77% in Group A and 30% in Group B. Follow-up magnetic resonance imaging of the patients in Group A showed spontaneous regression of a herniated mass in 10 patients (59%), Diffuse-type herniations were more likely to regress spontaneously than focal-type herniation (78% vs. 37%). Conclusions. Conservative treatment is an effective treatment option for mild cervical myelopathy caused by cervical soft disc herniation. A good outcome can be expected in patients with a median-type and/or diffuse-type herniation on magnetic resonance imaging.