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In Reply: Thirty-Day Hospital Readmission and Surgical Complication Rates for Shunting in Normal Pressure Hydrocephalus: A Large National Database Analysis

Heth, Jason A MD

doi: 10.1093/neuros/nyaa388
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To the Editor:

We appreciate the writers’ interest1 in our report entitled “Thirty-Day Hospital Readmission and Surgical Complication Rates for Shunting in Normal Pressure Hydrocephalus: A Large National Database Analysis.”2 We congratulate the writers on their reported results3 and agree with them that dedicated centers of excellence have the potential to improve outcomes and reduce complications. Our data arose from the Clinformatics™ Data Mart database (Optum®, Eden Prairie, Minnesota), which contains deidentified claims from a large, private healthcare network. These data do not include granular information on what proportion of patients are cared for at high-volume centers or dedicated normal pressure hydrocephalus (NPH) programs, though the data undoubtedly include results from some of these patients. Therefore, we do not believe it can be concluded that our data are representative only of centers without a specialized NPH program. We also do not believe the complication rates that we reported support that conclusion, as our finding of a 21.15% perioperative complication rate is well within overall adverse event rates reported from major centers in the United States ranging from 19% to 47.1%,4-7 36% in Europe,8 and 15% in Japan.9 Inclusion of the broadest range of complications can make the complication rate appear unacceptably high; therefore, one can stratify complications in different ways to identify only serious adverse events. Again, our data include a 30-d reoperation rate of 5.9%, which is well within the range of reported severe complications in single centers or clinical trials (15% reoperation rate in Schenker et al,8 21% revision surgery rate in ventriculoperitoneal [VP] shunts in Bhargav et al,10 and 15% severe adverse event rate in Miyajima et al9). Furthermore, a meta-analysis by Giordan and colleagues11 notes complication rates of 9% subdural collections; 2% each for ischemic/hemorrhagic event, postoperative infection, and seizure; and a 16% reoperation rate. Although an addition of these is not statistically valid, the total of 15% for subdural collections, stroke, infections, and seizures is on the order of other reported rates of serious complication and revision. Finally, another administrative database study examining the Nationwide Inpatient Sample to compare endoscopic third ventriculostomy outcomes with those of VP shunting reports a rate of any complication in VP shunting of 11.8%.12 One should note that chronic subdural hematomas or hygromas that can be eliminated with a programmable valve adjustment to reduce cerebrospinal fluid drainage are often viewed as less severe adverse events; this is not necessarily the case. When cerebrospinal fluid drainage is reduced, patients and family members frequently notice worsening of gait and occasional falls as a result. Therefore, even chronic subdural hematomas in NPH patients are not entirely innocuous.

When neurosurgeons discuss VP shunt implantation with patients diagnosed with NPH and their families, the procedure may be characterized as “low risk.” We report data that are comparable with results reported by high-volume and dedicated NPH programs. Therefore, we conclude that VP shunting for NPH has a higher risk than may be generally purported. We strongly agree with the writers that VP shunt implantation is a valuable procedure to improve the lives of properly selected patients diagnosed with NPH and offer these data to help neurosurgeons and neurologists fully inform patients and their families as they consider surgery.


This study did not receive any funding or financial support.


The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.


1. D’Antona   L, Thompson   SD, Thorne   L, et al.  Letter: thirty-day hospital readmission and surgical complication rates for shunting in normal pressure hydrocephalus: a large national database analysis. Neurosurgery. published online: 2020 (doi:10.1093/neuros/nyaa386).
2. Nadel   JL, Wilkinson   DA, Linzey   JR, et al.  Thirty-day hospital readmission and surgical complication rates for shunting in normal pressure hydrocephalus: a large national database analysis. Neurosurgery. 2020;86(6):843-850.
3. D’Antona   L, Blamey   SC, Craven   CL, et al.  Early postoperative outcomes of normal pressure hydrocephalus. published online: December 3, 2019. J Neurosurg Anesthesiol. (doi:10.1097/ANA.0000000000000668).
4. Hung   AL, Vivas-Buitrago   T, Adam   A, et al.  Ventriculoatrial versus ventriculoperitoneal shunt complications in idiopathic normal pressure hydrocephalus. Clin Neurol Neurosurg. 2017;157:1-6.
5. Kotagal   V, Walkowiak   E, Heth   JA. Serious adverse events following normal pressure hydrocephalus surgery. Clin Neurol Neurosurg. 2018;170:113-115.
6. McGovern   RA, Kelly   KM, Chan   AK, Morrissey   NJ, McKhann   GM  2nd. Should ventriculoatrial shunting be the procedure of choice for normal-pressure hydrocephalus?  J Neurosurg. 2014;120(6):1458-1464.
7. Wu   EM, El Ahmadieh   TY, Kafka   B, et al.  Ventriculoperitoneal shunt outcomes of normal pressure hydrocephalus: a case series of 116 patients. Cureus. 2019;11(3):e4170.
8. Schenker   P, Stieglitz   LH, Sick   B, Stienen   MN, Regli   L, Sarnthein   J. Patients with a normal pressure hydrocephalus shunt have fewer complications than do patients with other shunts. World Neurosurg. 2018;110:e249-e257.
9. Miyajima   M, Kazui   H, Mori   E, Ishikawa   M, SINPHONI-2 Investigators. One-year outcome in patients with idiopathic normal-pressure hydrocephalus: comparison of lumboperitoneal shunt to ventriculoperitoneal shunt. J Neurosurg. 2016;125(6):1483-1492.
10. Bhargav   AG, Rinaldo   L, Lanzino   G, Elder   BD. Comparison of complication and revision rates after frontal versus parietal approach for ventricular shunt placement in idiopathic normal pressure hydrocephalus. World Neurosurg. 2019;126:e1017-e1022.
11. Giordan   E, Palandri   G, Lanzino   G, Murad   MH, Elder   BD. Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis. published online: November 1, 2018. J Neurosurg. (doi:10.3171/2018.5.JNS1875).
12. Chan   AK, McGovern   RA, Zacharia   BE, et al.  Inferior short-term safety profile of endoscopic third ventriculostomy compared with ventriculoperitoneal shunt placement for idiopathic normal-pressure hydrocephalus. Neurosurgery. 2013;73(6):951-961; discussion 960-951.
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