Department of Orthopaedic Surgery, National Hospital Organization Miyazaki Higashi Hospital, 4374-1 Tayoshi Ooaza, Miyazaki, 880-0911, Japan.
Department of Orthopaedic Surgery, University of Miyazaki Faculty of Medicine, Miyazaki, Japan.
J Med Case Rep. 2023 Feb 24;17(1):82. doi: 10.1186/s13256-022-03749-1.
A nerve root anomaly, typified by a conjoined nerve root, is a rare finding. Conjoined nerve root anomalies are easily missed even in preoperative advanced imaging modalities, which can be potentially troublesome during and after surgery. In this report, we present a case of conjoined right L5-S1 nerve root in a patient with lumbar disc herniation, accompanied by spina bifida occulta, which was undiagnosed on preoperative imaging studies.
A 55-year-old Asian (Japanese) woman presented with low back pain and right leg radiating pain due to lumbar disc herniation at the right L5/S1. Physical examination revealed a positive Lasègue sign and the range of the straight leg raising test was 20° on the right side. The right patellar tendon reflex was normal; however, the right ankle jerk reflex disappeared. Although no obvious hypoesthesia was noted, mild muscle weakness (4/5) was observed in the right leg on the manual muscle test. We planned the lumbar discectomy under a microscope. During surgery, the conjoined right L5-S1 nerve root, which was compressed by herniated nucleus pulposus, was encountered. Although it was very thick and less mobile, some pieces of herniated nucleus pulposus could be removed piece by piece from the axillary part. After sequential decompressive procedures, the tightness of the conjoined right L5-S1 nerve root decreased but its mobility did not improve much. The laterality of the thickness and exit angle of the conjoined right L5-S1 nerve root was retrospectively confirmed on T2 coronal magnetic resonance images and magnetic resonance neurography. Postoperatively, right leg pain was immediately alleviated and complete improvement of muscle weakness was achieved 1 week later (5/5).
Magnetic resonance neurography is extremely useful for the accurate diagnosis of anomalous nerve roots because of clear visualization of the neural tissue. Discectomy under a microscope, which enables magnified three-dimensional observation of the surgical field, must provide a valid and safe procedure to achieve not only secure resection of herniated discs but also adequate exposure of anomalous nerve roots.
神经根异常，以神经根联合为特征，是一种罕见的发现。即使在术前的高级影像学检查中，神经根联合异常也很容易被忽视，这可能会在手术中和手术后带来麻烦。在本报告中，我们介绍了一例腰椎间盘突出症合并隐性脊柱裂的右侧 L5-S1 神经根联合病例，该病例在术前影像学检查中未被诊断。
一名 55 岁的亚洲（日本）女性因右侧 L5/S1 腰椎间盘突出症出现腰痛和右下肢放射痛。体格检查发现直腿抬高试验阳性，右侧直腿抬高试验范围为 20°。右侧髌腱反射正常；然而，右侧踝反射消失。虽然没有明显的感觉减退，但在徒手肌力测试中，右侧下肢观察到轻微的肌无力（4/5）。我们计划在显微镜下进行腰椎间盘切除术。在手术中，遇到了受压的右侧 L5-S1 神经根联合，该神经根联合由突出的椎间盘压迫。尽管它非常厚且活动度较小，但可以从腋部逐个切除一些突出的椎间盘。在进行连续减压手术后，联合的右侧 L5-S1 神经根的紧张度降低，但活动度改善不大。联合的右侧 L5-S1 神经根的厚度和出口角度的侧向性在 T2 冠状磁共振图像和磁共振神经成像上得到了回顾性确认。术后，右下肢疼痛立即缓解，1 周后肌无力完全改善（5/5）。
磁共振神经成像对于异常神经根的准确诊断非常有用，因为它可以清晰地显示神经组织。显微镜下的椎间盘切除术可以提供有效的、安全的手术程序，不仅可以安全切除椎间盘突出，还可以充分暴露异常神经根。
