Extent of Disc Degeneration after Single-Level Cervical Anterior Microforaminotomy Analyzed with Long-Term Radiological Data

OBJECTIVE: To prove the extents and details of cervical degeneration after anterior microforaminotomy (AMF) with 6-years follow-up. METHODS: A retrospective study of 24 patients, underwent single-level AMF, was performed. Clinical and radiologic data were analyzed with office charts, questionaires, and picture achieving and communication system images. RESULTS: According to Odom's criteria, 91.6% achieved favorable outcome. The mean visual analog scale score was improved from 8.6 to 3, and the mean neck disability index was improved from 27.9 to 7.3 (p<0.01). Eighteen cases (75%) showed disc height (DH) decrease. The disc invasion was correlated with DH decrease (p<0.05). The disc height decrease correlated with static, dynamic changes of shell angle and spur formation (p<0.05). Any radiological parameters did not affect the clinical outcome. CONCLUSION: AMF is an effective technique for treating unilateral cervical radiculopathy. It showed excellent surgical outcomes even in long-term follow-ups. However, a decrease in DH occurred in a considerable number of patients. Disc invasion during surgery may be the trigger of sequential degeneration.

Does the Size of Anterior Microforaminotomy Affect the Surgical Outcome? / 이화의대지

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Anterior Cervical Microforaminotomy / 한양의대학술지

Anterior cervical microforaminotomy is the one of surgical options for treating cervical spondylotic lesions manifested by radiculopathy or myelopathy. This minimally invasive surgical procedure is gaining popularity due to the recent trends of avoidance of spinal fusion resulting in loss of the physiologic spinal motion and developing a future adjacent segment syndrome. Although the spinal fusion still remains a gold standard procedure for degenerative cervical spinal diseases, the eager for maintaining the function of the motion segment is another issue for contemporary spinal surgeons. Anterior cervical microforaminotomy is a target-oriented operation that decompresses the nerve root or spinal cord without destruction of the spinal anatomical functional unit. Unlike to other procedures including total or partial resection of the intervertebral disc, this surgical procedure removes only a small part of the uncovertebral joint or vertebral body. Through this narrow corridor, adequate decompression of the nerve root or spinal cord can be achieved while preserving functional motion. Technical variations of the original anterior cervical microforaminotomy have been continuously developed to minimize the concerns for the postoperative disc height loss and instability. As of now, the anterior cervical microforaminotomy and its technical variations have been proved to be an excellent procedure for treating the cervical spondylotic radiculopathy from literatures review. But the long-term clinical results and the efficacy of the procedure for cervical myelopathy still remain to be seen.

Morphometric Measurement of the Anatomical Landmark in Anterior Cervical Microforaminotomy

OBJECTIVE: The lack of anatomical knowledge for the anterior cervical microforaminotomy is liable to injure the neurovascular structures. The surgical anatomy is examined with special attention to the ventral aspect exposed in anterior cervical microforaminotomy. METHODS: In 16 adult formalin fixed cadaveric cervical spine, the author measured the distances from the medical margin of the longus colli to the medical wall of the ipsilateral vertebral artery and the angle for the ipsilateral vertebral artery. The distances from the lateral margin of the posterior longitudinal ligament to the medial margin of the ipsilateral medial wall of the vertebral artery, to the ipsilateral dorsal root ganglion was measured too. RESULTS: The distance from the medial margin of the longus colli to the ipsilateral vertebral artery was 13.3~14.7mm and the angle for the ipsilateral vertebral artery was 41~42.5 degrees. The range of distance from the lateral margin of the posterior longitudinal ligament to the ipsilateral vertebral artery was 11.9~16.1mm, to the ipsilateral dorsal root ganglion was 11.6~12.9mm. CONCLUSION: These data will aid in reducing neurovascular injury during anterior cervical approaches.

Midterm Follow-up Results of Anterior Cervical Microforaminotomy

OBJECTIVE: We have previously reported excellent early clinical results of anterior cervical microforaminotomy(ACMF) for patients who have cervical radiculopathy from either disc herniation or foraminal stenosis. ACMF is being accepted as a minimal invasive functional spinal surgery, but their long-term outcome is unknown. The goal of this study is to evaluate the midterm clinical and radiological results of ACMF. METHODS: We had undertaken a questionnaire survey and retrospective analysis of 42 patients with cervical radiculopathy who had undergone ACMF from 1998 to 2001. Clinical data from 33 patients(one-level operation in 20 patients, two-level in 13 patients) and radiological data from 21 patients were analysed. RESULTS: Thirty-three patients answered for the questionnaires. Mean follow-up was 48 months(ranged from 26 to 64 months). The surgical outcome was excellent in 18 patients(54.6%) and good in 11 patients(33.3%). One patient showed poor outcome, but there was no case of recurrence, reoperation or additive surgery. Twenty-four patients(79%) satisfied with the results of their surgery. On the average, the loss of disc height was 1.02mm(18% of preoperative disc height), average increase of displacement was 0.83mm, decrease of sagittal plane angulation was 2.03 degrees. All the patients maintained stability during follow-up period. CONCLUSION: In the midterm, ACMF appears to be safe and effective method for the treatment of cervical radiculopathy. To prevent disc height loss and retrolisthesis, skilled disc-preserving technique of ACMF is required and modified technique preserving anterior part of uncovertebral joint may be advantageous.

The Result of Posterior Microforaminotomy for Posterolateral Herniation of Cervical Discs

OBJECTIVE: To evaluate the effectiveness of posterior microforaminotomy in treatment of posterolateral cervical disc herniation, the authors retrospectively analyzed the result of posterior microforaminotomy in our institute. PATIENTS AND METHODS: Ten patients with radiculopathy due to posterolateral cervical disc herniation have been treated with posterior microforaminotomy from August 1996 to July 2000. We analyzed clinical results in all patients who were followed up for an average of 10 months. RESULTS: The mean age was 47.2 years and all patients were treated with posterior microforaminotomy as primary treatment. one patient was received anterior cervical interbody fusion with iliac bone 12 years before. Clinical improvement in the last follow-up were seen in all patients and there were no complications. CONCLUSION: Microcervical foraminotomy is considered useful operative method for posterolateral soft disc herniation. We conclude that the posterior microforaminotomy for radiculopathy due to soft posterolateral cervical disc herniation seems to be safe and effective in selective patients.