Williams Adam P, Germon Tim
Department of Neurosurgery, Derriford Hospital, Plymouth PL6 8DH, UK.
Department of Neurosurgery, Derriford Hospital, Plymouth PL6 8DH, UK.
Spine J. 2015 Mar 2;15(3 Suppl):S44-S49. doi: 10.1016/j.spinee.2015.01.004. Epub 2015 Jan 8.
Pain as a consequence of nerve root compression may not be easy to diagnose. Degenerative changes causing nerve root compression on magnetic resonance imaging (MRI) are common but not necessarily symptomatic while the distribution of pain attributable to a particular nerve root is variable. Selective dorsal root ganglion blocks (DRGBs) have been used in these situations to aid the diagnostic process, although their use remains controversial.
We sought to investigate the positive predictive value of DRGBs in predicting response to decompressive surgery on a particular nerve root in a patient cohort with diagnostic uncertainty after clinical examination and MRI.
STUDY DESIGN/SETTING: This was a retrospective review of prospectively collected data on 100 consecutive patients.
One hundred consecutive patients who underwent diagnostic DRGB under the senior author were identified retrospectively. Clinical records were reviewed for the reason for diagnostic uncertainty, level assessed, whether the DRGB reproduced pain typical for the patient's symptoms, whether there was anatomically appropriate sensory and motor disturbance, whether good pain relief was achieved, and whether they had good response to surgery.
Of 100 patients recruited, four were removed from analysis owing to inadequate surgical decompression proven on postoperative MRI. Of the remaining 96 patients, 74 achieved immediate relief in their symptoms after DRGB. Fifty-one patients underwent surgical decompression after a successful root block; 41 patients achieved a good result from this surgery, and 10 did not. Nine patients who had no relief in their symptoms from DRGB still underwent surgery to decompress the same nerve root; six patients had relief of their symptoms from surgery, two did not respond, and one was lost to follow-up. The most common reason for diagnostic uncertainty was multilevel disease (74%) followed by patients with atypical pain (23%). The most common level assessed was the L5 nerve root. The positive predictive value was found to be 80.4%, the negative predictive value was 22.2%, with a sensitivity of 85.4% and a specificity of 16.7%.
In patients with diagnostic doubt, a positive DRGB is a good predictor of a positive outcome after surgery to decompress that nerve root. However, the negative predictive value is poor. This result could almost certainly be improved if there was a better definition of what constitutes a positive, and more importantly a negative, DRGB result. In the meantime, DRGBs are a useful adjunct in predicting the outcome of decompressive surgery in people with pain as a consequence of potential lumbosacral nerve root compression.
神经根受压所致疼痛可能不易诊断。磁共振成像（MRI）显示的导致神经根受压的退行性改变很常见，但不一定有症状，而特定神经根所致疼痛的分布则具有变异性。在这些情况下，选择性背根神经节阻滞（DRGB）已被用于辅助诊断过程，尽管其应用仍存在争议。
我们试图在一组经临床检查和MRI后诊断仍不明确的患者中，研究DRGB对预测特定神经根减压手术反应的阳性预测价值。
研究设计/地点：这是一项对前瞻性收集的100例连续患者数据的回顾性研究。
回顾性确定100例在资深作者指导下接受诊断性DRGB的连续患者。查阅临床记录，了解诊断不明确的原因、评估的节段、DRGB是否再现了患者典型症状的疼痛、是否存在解剖学上合适的感觉和运动障碍、是否实现了良好的疼痛缓解以及他们对手术的反应是否良好。
在招募的100例患者中，4例因术后MRI证实减压不充分而被排除在分析之外。在其余96例患者中，74例在DRGB后症状立即缓解。51例患者在成功进行神经根阻滞后接受了手术减压；41例患者手术效果良好，10例效果不佳。9例DRGB后症状未缓解的患者仍接受了相同神经根的减压手术；6例患者手术后症状缓解，2例无反应，1例失访。诊断不明确的最常见原因是多节段疾病（74%），其次是非典型疼痛患者（23%）。评估最常见的节段是L5神经根。发现阳性预测值为80.4%，阴性预测值为22.2%，敏感性为85.4%，特异性为16.7%。
在诊断存疑的患者中，阳性DRGB是该神经根减压手术后阳性结果的良好预测指标。然而，阴性预测值较差。如果能更好地定义什么构成阳性，更重要的是阴性DRGB结果，几乎可以肯定这个结果会得到改善。与此同时，DRGB在预测因潜在腰骶神经根受压而疼痛的患者减压手术结果方面是一种有用的辅助手段。
