Extraforaminal Lumbar Disc Herniation Research Articles

当院における外側型腰椎椎開板ヘルニアの検討

Between June, 1994 and July, 2003, a total of 370 patients underwent lumbar discectomy for herniated nucleus pulposus. Twenty-two patients (5.9%) were diagnosed as having extraforaminal lumbar disc herniation (ELDH). The average age at the time of surgery was 55.4 years. The level was L2/3 in one case, L3/4 in five cases, L4/5 in nine cases, and L5/S1 in seven cases. Myelography was normal in 14 cases and abnormal in eight cases. However, ELDH was not diagnosed. In only one out of 17 cases, ELDH could not be detected on magnetic resonance imaging (MRI). Selective nerve root block was performed in 16 cases. Pain was reproduced and clinical symptoms improved transiently by nerve root block in all cases. Accurate diagnosis of ELDH was achieved with CT-discography (CTD) in 12 out of 12 cases (100%). Myelography is basically of no value as a diagnostic technique for ELDH. MRI more or less clearly demonstrates the pathology, but present certain cases as false normal. Selective nerve root block is useful for diagnosis at the pathological level. CTD is an excellent diagnostic technique for ELDH, but in order to identify ELDH, it has to be performed whenever myelography is normal or equivocal. In all cases, we performed resection of herniated discs following lateral fenestration. Clinical symptoms improved in all cases after surgery.Accurate preoperative diagnosis estimated by CTD is crucial in order to obtain satisfactory operative results.

Extraforaminal lumbar disc herniations: microsurgical anatomy and surgical approach.

Familiarity with the microsurgical anatomy of the far-lateral compartment is essential for operating in patients with far-lateral discs. In this report the authors address the microsurgical anatomy studied in 24 extraforaminal lumbar disc spaces in three cadavers. Cadaveric dissections confirmed the authors' operative experience in which they found an arterial arcade to be associated with the nerve trunk. The main trunk of the lumbar artery was located lateral to the exiting nerve root in the region of intervertebral foramen. The trunk of the lumbar spinal nerve descending from the level above was 7 mm (+/- 3 mm [standard deviation]) lateral to the lumbar artery. Clarification of the microsurgical anatomy of the far-lateral compartment confirmed the authors' clinical impression that the optimum approach to far-lateral discs is via the inferomedial quadrant of the extraforaminal compartment. In this quadrant, exposure of the main nerve root can be facilitated by dividing the posterior primary ramus and a newly described arterial arcade that envelops the nerve trunk. Once this arcade is divided, the nerve can be retracted with relative ease and safety, and the disc can be removed more easily.

Clinical features of extraforaminal lumbar disc herniation based on the radiographic location of the dorsal root ganglion.

The relations between the location of the dorsal root ganglion and pre- and postoperative symptoms were reviewed retrospectively in 27 patients who underwent radiculography and posterior discectomy. To evaluate the clinical features and surgical outcome of extraforaminal lumbar disc herniation based on the location of dorsal root ganglion. The location of dorsal root ganglia has been reported to be correlated with a variety of radicular symptoms. Extraforaminal lumbar disc herniation has several specific clinical features, one of which is severe radicular pain. However, there is no report in the literature on the association between the location of the dorsal root ganglia and the severity of the symptoms of extraforaminal lumbar disc herniation. The radiographic location of the dorsal root ganglion of each compressed nerve root was determined by preoperative direct radiculograms. All patients were classified into the following three groups according to the location of dorsal root ganglion: intraspinal, intraforaminal, and extraforaminal. The incidences of these locations were 5 of 27 (18.5%), 15 of 27 (55.5%), and 7 of 27 (25.9%), respectively. The relation between the location of the dorsal root ganglion and clinical parameters such as the level of the compressed nerve root, the degree of limitation on straight leg raising test, the severity of the pre- and postoperative subjective symptoms (leg pain, low back pain, and walking capacity), clinical signs (sensory and motor disturbance), and the recovery rate were investigated. The degree of limitation on the straight leg raising test in the extraforaminal group tended to be low, compared with that in the intraspinal and intraforaminal groups. Low back pain in the extraforaminal group was more severe than that in the intraspinal and intraforaminal groups. Preoperative leg pain in the extraforaminal group was significantly more severe that that in the intraspinal group, and the walking capacity in the extraforaminal group tended to be lower than that in the intraspinal and intraforaminal groups. No significant differences were found between the location of dorsal root ganglion and the preoperative sensory or motor disturbance and surgical outcomes. The location of the dorsal root ganglion might influence the severity of radicular symptoms (pain and walking distance tolerance) in patients with extraforaminal lumbar disc herniation.

Long-term follow up of patients surgically treated by the far-lateral approach for foraminal and extraforaminal lumbar disc herniations.

This study was undertaken to evaluate the long-term benefit in 202 patients who were surgically treated via a microsurgical far-lateral approach for foraminal or extraforaminal lumbar disc herniations. All patients underwent surgery at the authors' institute since 1987 and represented 6.5% of all lumbar spinal disc surgeries. There were 67 women and 135 men who ranged in age from 19 to 78 years (mean age 58 years). All patients had unilateral leg pain due to lumbar disc herniations into or lateral to the lateral interpedicular compartment. One patient underwent surgery at the L1-2 level, nine at L2-3, 48 at L3-4, 86 at L4-5, and 58 at the L5-S1 level. The mean follow-up period was 50 months (range 12-120 months). Outcome was defined as excellent (no pain), good (some back pain), fair (moderate radiculopathy), and poor (unchanged or worse) based on Macnab classification. Overall, excellent and good results were achieved in 62 (31%) and 85 (42%) patients, respectively, and fair and poor results in 40 (20%) and 15 (7%) patients, respectively. Of 11 recurrent disc herniations, four presented in an extreme-lateral position, five in a paramedian location, and two on the contralateral side. There were three minor complications related to surgery, seven general complications, and no case of spinal instability. The far-lateral approach is a safe, effective procedure that avoids the risk of secondary spinal instability.

Long term follow-up of osteoplastic laminectomy for extraforaminal lumbar disc herniation evaluated by 3D-CT

Long term follow-up of osteoplastic laminectomy for extraforaminal lumbar disc herniation evaluated by 3D-CT

腰部外側神経根障害におけるＭＲＩの有用性

This study evaluated the usefulness of MRI in the diagnosis of intra and extraforaminal lumbar nerve root compression, which is difficult to diagnose by myelogram. We retrospectively analyzed 14 patients with intra and extraforaminal lumbar disc herniation and 7 patients with lumbar foraminal encroachment between July 1993 and June 1996.Parasagittal and axial images in T2WI were analyzed. Decrease of fat tissue around the nerve root was reported in 92.9% of cases with in lumbar disc herniation and 100% in foraminal encroachment. Enhanced MRI was useful for identifying nerve root compression caused by lumbar disc herniation which we couldn't diagnose by parasagittal and axial MRI.

Microsurgical anatomy of the lateral approach to extraforaminal lumbar disc herniations.

During the "lateral" approach to extraforaminal lumbar disc herniations, the surgeon may be confronted with considerable variations in anatomy, making this approach extremely difficult in some patients. An anatomic study, therefore, was undertaken to examine the bony boundaries of the operative target, the medial intertransverse space. In 31 lumbar spine specimens taken from cadavers of people who had been between 30 and 93 years old at death, the relevant distances and proportions of the operative window were measured at the levels L1-L2 to L5-S1. Measurements revealed that the operative window in a systematic fashion becomes progressively smaller as the approach moves from L1-L2 toward L5-S1: 1) from L1 to L5, the medial boundary, the isthmus laminae, gradually extends farther laterally and eventually covers the waist of the respective vertebral body; 2) the lower boundary, the facet joint, gradually overlaps the disc space in an upward and lateral direction; 3) the upper boundary, the transverse process, gradually moves downward. Anatomic variations and abnormalities are found particularly often at the L5-S1 level. The anatomic findings led to important conclusions regarding the microsurgical approach to extraforaminal lumbar disc herniations; at levels L1-L2 to L3-L4, the midline approach with lateral retraction of the paraspinal muscles allows for efficient exposure of the lateral neural foramen and avoidance of trauma to the facet joint. Often at level L4-L5, and nearly always at level L5-S1, a tangential route through a paramedian transmuscular approach offers many advantages.

Ｅｘｔｒａｆｏｒａｍｉｎａｌ ｌｕｍｂａｒ ｄｉｓｃ ｈｅｒｎｉａｔｉｏｎ（ＥＬＤＨ）に対する骨形成的偏側椎弓切除術

We present a series of 30 patients who were diagnosed as having extraforaminal lumbar disc herniations and underwent osteoplastic hemilaminectomy. Subjects included 20 male and 10 female patients, with an average age of 51 years. Regarding the level of the herniation, fifteen were at the L5-S level, nine at the L4-5 level, six at the L3-4 level and one at the L2-3 level. The follow-up period varied between 11 months and 104 months, with an average of 54.7 months.The results were as follows. The mean JOA score was 27.5 at the last follow-up, compared to 12.4 pre-operatively. Complete union was achieved in all osteotomy cases. No patient suffered spinal instability postoperatively.An advantage of osteoplastic hemilaminectomy is that it allows a comprehensive view of the nerve root canal throughout the intraforaminal and extraforaminal zones and preserves posterior structures such as the facet joint and pars interarticularis.

Diagnosis and Operative Treatment of Intraforaminal and Extraforaminal Nerve Root Compression

The clinical, radiologic, and operative findings, and clinical results in 26 cases of foraminal nerve root involvement, each treated by variable operative procedures for an existing pathologic condition, were studied. These 26 cases consisted of 8 intraforaminal or extraforaminal lumbar disc herniations and 18 foraminal nerve root entrapments. The cases with an extreme lateral lumbar disc herniation underwent lateral fenestration or osteoplastic hemilaminectomy without concomitant spinal fusion, and showed excellent operative results. A sufficient selective decompression was achieved with a good clinical result in the cases of lumbar spondylosis without preoperative spinal instability, by lateral fenestration or osteoplastic hemilaminectomy. This result suggests that the selective decompression procedure is recommended for cases with reliable preoperative diagnoses. When an intraspinal lesion makes it difficult to diagnose coexisting foraminal nerve root involvement, decompression of the nerve root canal, approaching from medial to lateral, is recommended. The fusion operation should be performed in cases undergoing even a unilateral total facetectomy, regardless of the patient's old age. A correct preoperative diagnosis is crucial in order to obtain satisfactory operative results.

A Case of Recurrent Extraforaminal Lateral Lumbar Disc Herniation Occurring at the Same Level and on the Opposite Side

We reported the only known case of recurrent extraforaminal lumbar disc herniation occurring at the same level but on the opposite side. In performing lumbar disc puncture for discography, when an extraforaminal bulge is seen on CT scan, we recommend puncture through the side opposite the bulge to prevent new herniation even if the symptoms are located on the side of the puncture.

Extraforaminal lumbar disc herniations: CT demonstration of Sharpey's fibers avulsion.

Forty-seven extraforaminal lumbar disc herniations (EFLDH) accounting for 7% of all lumbar disc herniations encountered during the same period of time were reviewed. L3-L4 or L4-L5 disc was involved in 89% of the cases giving rise to a L3 or L4 nerve root compression. An abnormal motion of lateral bending with rotation of the trunk was found retrospectively in 60% of the patients. In 53% of all EFLDH a bony avulsion of the vertebral end-plate facing the herniation was demonstrated at the site of attachment of Sharpey's fibers. This study suggests that this previously undescribed bony change witnesses a special injury of the spine responsible for most EFLDH.

Foraminal and extraforaminal lumbar disc herniation: diagnosis and treatment.

During a 1-year period from December 1, 1984, through November 30, 1985, a total of 174 patients underwent lumbar discectomy for herniated nucleus pulposus. Eighteen (10.3%) were diagnosed as having foraminal or extraforaminal disc herniations. Sixteen patients are included in this study. All patients were evaluated with computed tomography, metrizamide myelography, discography, and discography-enhanced computed tomography (disco-CT). Accurate diagnosis of foraminal or extraforaminal herniation was made with disco-CT in 15 of 16 cases (93.8%), compared with discography alone (37.5%), computed tomography alone, and/or myelography-enhanced computed tomography (50%) and myelography alone (12.5%). Surgical treatment with bilateral hemilaminectomy, partial medial facetectomy, and partial internal foraminotomy, if needed, followed by discectomy is very effective and the favored surgical management for nerve root decompression in most all cases.