Anterior microforaminotomy (AMF) is an alternative procedure to treat unilateral cervical pathology. Although the results have been reported favorable in the previous studies, postoperative degeneration may occur. We analyze long-term outcome to determine the critical size of AMF.

A retrospective study was performed. Clinical data with chart review, radiologic data with picture archiving and communication system (PACS) images were obtained. Long-term clinical outcomes were accessed by a questionnaire, including visual analogue scale (VAS) and neck disability index (NDI). Various clinical, radiological data were statistically analyzed.

Eight-two patients were enrolled in this study. Main pathology was spondylotic spur (53.7%), soft disc herniation (36%). Mean age was 49 years old. There was no surgery-related complication. Mean follow-up was 6.1 years. 90.3% showed favorable clinical outcome. Mean VAS score was decreased from 8.2 to 2.9, and NDI score was decreased from 24.5 to 6.7 (P<0.05). 88.7% showed decrease of disc height (DH), and mean change was 1 mm. DH change was correlated positively with the disc invasion and AMF diameter (P<0.05). Mean diameter of AMF was 5.2 mm. According to statistical analysis, the critical diameter of AMF was 4.7 mm, directly affecting DH decrease. Any radiological parameters did not affect the clinical outcome.

AMF was an effective procedure to treat unilateral cervical pathology. Critical DH decreases and/or disc invasion may be the trigger of sequential degeneration. To preserve DH, AMF diameter should be small and disc invasion should be avoided.

In order to evaluate clinical significance of MR signal change within vertebral body marrow, we investigated the relationship between signal change of marrow and duration of low back pain, hight of disc, segmental hypermobility, disc degeneration and degree of disc herniation.

We reviewed retrospectively simple radiograph, flexion-extension dynamic radiograph and MR images of the lumber spines(L3-S1) of 100 patients, who underwent discectomy at Ewha Womans University Mokdong Hospital from September 1993 to October 1996.

1) There were Modic type 2 changes in 36 patients of 100 patients(36%) and in 52 segments of 300 segments(17.3%). 2) Average was older in the group with signal change in marrow than in that without signal change. 3) Signal change of vertebral body marrow was not significantly related to duration of low back pain. 4) Decreased disc heght was more frequently found in segments with signal change in marrow than in those without signal chagne. 5) Modic type 2 changes was not related to lumbar segmental hypermobility. 6) Degeneration of disc was more frequently found in segments with signal change in marrow than in those without signal change. 7) Signal change of vertebral body marrow was not directly related to degree of disc herniation.

Signal change of vertebral body marrow in MRI was significantly related to age, disc height and degree of disc degeneration, and it suggests that the marrow change can be induced by response of vertebral body to the changed mechanical environment, which is due to long-standing disc degeneration.