Validity of Shunt Pumping Test as a Screening Modality for Shunt Block: An Experimental Study

Abstract

Purpose To ascertain the validity and efficacy of shunt compression test in evaluating a blocked shunt.

Methods An experimental model was created using a Chhabra shunt, and 25 physicians with 1 to 3 years of experience in neurosurgery were asked to assess the block in the model where artificial blocks were created.

Results The sensitivity of test to detect any block was found to be 0.76 (95% confidence interval [CI]: 0.7–0.81), specificity was 0.71 (0.59–0.81), positive likelihood ratio 2.59 (1.81–3.7), and negative likelihood ratio 0.34 (026–0.45). Odds ratio for proximal block was 4.33 (95% CI: 2.01–8.92), and for distal block, it was 10.63 (95% CI: 10.63–22.32). Furthermore, predictive probability for shunt block was maximum when both the ends were considered to be blocked by the investigator and the test was found to be poor in predicting a patent shunt.

Conclusion This is not a very reliable screening test to detect presence of a shunt block. Predicted probability for shunt block was maximum when both the ends were considered to be blocked by the investigator. This study results are not in conformity with the previously held belief that delayed refilling of chamber would clearly aid the diagnosis of proximal end block. It is strongly felt that a deliberate training of shunt compression test would aid a better diagnostic ability.

Keywords

hydrocephalous - manual chamber compression test - ventriculoperitoneal shunt - blocked shunt

Publication History

Article published online:
17 April 2020

• References

• 1 Rekate HL. Shunt revision: complications and their prevention. Pediatr Neurosurg 1991-1992–92; 17 (03) 155-162
• 2 Sainte-Rose C, Piatt JH, Renier D. et al. Mechanical complications in shunts. Pediatr Neurosurg 1991–1992; 17 (01) 2-9
• 3 Lazareff JA, Peacock W, Holly L, Ver Halen J, Wong A, Olmstead C. Multiple shunt failures: an analysis of relevant factors. Childs Nerv Syst 1998; 14 (06) 271-275
• 4 Peacock WJ, Currer TH. Hydrocephalus in childhood. A study of 440 cases. S Afr Med J 1984; 66 (09) 323-324
• 5 Barnes NP, Jones SJ, Hayward RD, Harkness WJ, Thompson D. Ventriculoperitoneal shunt block: what are the best predictive clinical indicators?. Arch Dis Child 2002; 87 (03) 198-201
• 6 Watkins L, Hayward R, Andar U, Harkness W. The diagnosis of blocked cerebrospinal fluid shunts: a prospective study of referral to a paediatric neurosurgical unit. Childs Nerv Syst 1994; 10 (02) 87-90
• 7 Chiewvit S, Nuntaaree S, Kanchaanapiboon P, Chiewvit P. Assessment lumboperitoneal or ventriculoperitoneal shunt patency by radionuclide technique: a review experience cases. World J Nucl Med 2014; 13 (02) 75-84
• 8 Ejike JC, Bahjri K, Mathur M. What is the normal intra-abdominal pressure in critically ill children and how should we measure it?. Crit Care Med 2008; 36 (07) 2157-2162
• 9 Ouellette D, Lynch T, Bruder E. et al. Additive value of nuclear medicine shuntograms to computed tomography for suspected cerebrospinal fluid shunt obstruction in the pediatric emergency department. Pediatr Emerg Care 2009; 25 (12) 827-830
• 10 Sood S, Canady AI, Ham SD. Evaluation of shunt malfunction using shunt site reservoir. Pediatr Neurosurg 2000; 32 (04) 180-186
• 11 Piatt Jr JH. Pumping the shunt revisited. A longitudinal study. Pediatr Neurosurg 1996; 25 (02) 73-76, discussion 76–77
• 12 Johna S, Taylor E, Brown C, Zimmerman G. Abdominal compartment syndrome: does intra-cystic pressure reflect actual intra-abdominal pressure? A prospective study in surgical patients. Crit Care 1999; 3 (06) 135-138
• 13 Dunn LT. Raised intracranial pressure. J Neurol Neurosurg Psychiatry 2002; 73 (Suppl. 01) i23-i27