Seidel-Klinik, Clinic for Rheumatology, Spinal Disorders, and Neuromuscular Diseases, Bad Bellingen, Germany.
J Neurosurg Spine. 2010 Mar;12(3):314-9. doi: 10.3171/2009.9.SPINE09114.
Variation in the number of lumbar vertebrae occurs in a small portion of the population. Either the fifth lumbar vertebra shows assimilation to the sacrum or the first sacral vertebra shows a lumbar configuration, resulting in 4 or 6 lumbar vertebrae, respectively. Etiologically, lumbar nerve root syndrome is diagnosed by comparing the anatomical level of the disc herniation to the compressed nerve root and to the pattern of the peripheral sensory and motor deficit. In case of a variation in the number of lumbar vertebrae, defining the lumbar nerve roots becomes difficult. Variations in the number of lumbar vertebrae make the landmarks (the twelfth rib and the first sacral vertebra) unreliable clues to define the nerve roots. The allocation of the clinically damaged segment to the spinal disorder seen in imaging studies is essential for differential diagnosis and spine surgery.
A retrospective study was conducted of clinical, electrophysiological, and imaging data among inpatients over a period of 21 months. Eight patients who had isolated monosegmental discogenic nerve root compression and a variation in the number of lumbar vertebrae were selected.
Seven patients presented with 6 lumbar vertebrae, and 1 patient presented with 4 lumbar vertebrae and disc herniation on 1 of the 2 caudal levels. Compression of the second-to-last nerve root in patients with 6 lumbar vertebrae resulted either in clinical L-5 or S-1 syndrome, or a combination of both. Compression of the last caudal nerve root resulted in a clinical S-1 nerve root syndrome.
The findings suggest that the dermatomyotomal supply of the lumbosacral nerve roots can vary in patients with a variation in the number of lumbar vertebrae, and a meticulous clinical, radiological, and electrophysiological examination is essential.
腰椎椎体数量的变化在一小部分人群中发生。第五腰椎要么与骶骨融合，要么第一骶椎呈现腰椎形态，分别导致有 4 或 6 个腰椎。从病因学上讲，腰椎神经根综合征通过比较椎间盘突出的解剖水平与受压神经根以及周围感觉和运动缺陷的模式来诊断。在腰椎椎体数量发生变化的情况下，定义腰椎神经根变得困难。腰椎椎体数量的变化使得标志（第十二肋骨和第一骶椎）成为不可靠的线索来定义神经根。将临床上受损的节段分配给影像学研究中所见的脊柱疾病对于鉴别诊断和脊柱手术至关重要。
对 21 个月期间的住院患者的临床、电生理和影像学数据进行了回顾性研究。选择了 8 例孤立性单节段椎间盘源性神经根压迫和腰椎椎体数量变化的患者。
7 例患者有 6 个腰椎，1 例患者有 4 个腰椎，2 个尾侧水平各有 1 个椎间盘突出。6 个腰椎患者的倒数第二个神经根受压导致临床 L-5 或 S-1 综合征，或两者兼有。最后一个尾侧神经根受压导致临床 S-1 神经根综合征。
研究结果表明，在腰椎椎体数量变化的患者中，腰荐神经根的皮节供应可能会有所不同，因此需要进行细致的临床、放射学和电生理学检查。
