Rocque Brandon G, Lapsiwala Samir, Iskandar Bermans J
Department of Neurological Surgery, University of Wisconsin-Madison, Madison, Wisconsin 53792-8660, USA.
J Neurosurg Pediatr. 2008 Jun;1(6):439-43. doi: 10.3171/PED/2008/1/6/439.
The clinical diagnosis of cerebrospinal fluid (CSF) shunt malfunction can be challenging. In this prospective study, the authors evaluated a common method of interrogating shunts: the shunt tap; specifically, its ability to predict proximal malfunction.
The authors performed standardized shunt taps in a consecutive series of cases involving children with suspected or proven shunt malfunction, assessing flow and, when possible, opening pressure. Data were collected prospectively, and results analyzed in light of surgical findings.
A shunt tap was performed prior to 68 operative explorations in 51 patients. Of the 68 taps, 28 yielded poor or no CSF flow on aspiration. After 26 of these 28 procedures, proximal catheter obstruction was identified. After 28 taps with good CSF return and normal or low opening pressure, 18 shunts were found to have a proximal obstruction, 8 had no obstruction, and 2 had a distal obstruction. Another 12 taps with good CSF flow had high opening pressure; subsequent surgery showed distal obstruction in 11 of the shunts, and proximal obstruction in 1. The positive predictive value of poor flow was 93%, while good flow on shunt tap predicted adequate proximal catheter function in only 55% of cases.
Poor flow of CSF on shunt tap is highly predictive of obstruction of the proximal catheter. Because not all patients with good flow on shunt tap underwent surgical shunt exploration, the specificity of this test cannot be determined. Nonetheless, a shunt tap that reveals good flow with a normal opening pressure can be misleading, and management of such cases should be based on clinical judgment.
脑脊液（CSF）分流器故障的临床诊断可能具有挑战性。在这项前瞻性研究中，作者评估了一种常用的分流器检查方法：分流器穿刺；具体而言，评估其预测近端故障的能力。
作者对一系列连续的疑似或已证实分流器故障的儿童病例进行了标准化的分流器穿刺，评估流量，并在可能的情况下评估开放压。前瞻性收集数据，并根据手术结果分析结果。
在51例患者的68次手术探查前进行了分流器穿刺。在这68次穿刺中，28次抽吸时脑脊液流量不佳或无脑脊液流出。在这28次操作中的26次之后，发现了近端导管阻塞。在28次脑脊液回流良好且开放压正常或较低的穿刺后，发现18个分流器存在近端阻塞，8个无阻塞，2个存在远端阻塞。另外12次脑脊液流量良好的穿刺开放压较高；随后的手术显示，其中11个分流器存在远端阻塞，1个存在近端阻塞。流量不佳的阳性预测值为93%，而分流器穿刺时流量良好仅在55%的病例中预测近端导管功能正常。
分流器穿刺时脑脊液流量不佳高度提示近端导管阻塞。由于并非所有分流器穿刺时流量良好的患者都接受了手术分流探查，因此无法确定该检查的特异性。尽管如此，显示流量良好且开放压正常的分流器穿刺可能会产生误导，此类病例的处理应基于临床判断。
