CORRESPONDENCE TOPIC
CORRESPONDENCE
Reply to the Comment on the Article “National Variability in Intracranial Pressure Monitoring and Craniotomy for Children With Moderate to Severe Traumatic Brain Injury”
In Reply: Reply to the Comment on the Article “National Variability in Intracranial Pressure Monitoring and Craniotomy for Children With Moderate to Severe Traumatic Brain Injury”
After reading Dr Maas' comment regarding our recent article1 in Neurosurgery, we wish to make a few brief comments. With regard to the assertion that we reported a lower incidence of intracranial pressure monitoring (ICPM) in children aged 0 to 5 years: in fact, we reported a lower incidence of ICPM in infants (children aged ,1 year) in comparison with older children. The epidemiological importance of this finding, its persistent appearance in the literature,2,3 and the potential relevance for patient care all necessitate clarity in statement and the understanding of this distinction. Regarding the comment that adjustment for case mix between centers “was not possible” in our study: we believe that a distinction should be drawn between the lack of adjustment and the potential for incomplete adjustment. Although we would agree that the potential exists for incomplete adjustment in our work, the same is true for any nonrandomized study. Finally, with regard to the potential confounding of the Glasgow Coma Scale by sedation and neuromuscular blockade: with the use of limited clinical data, we sought to define a group of children with moderate or severe injury in order to examine the use of ICPM and craniotomy in those most likely to receive it. As stated in our methods, we performed a sensitivity analysis to examine the potential impact of sedation or paralytics on our results, and we found none.
In their Letter to the Editor, Drs Van Cleve and Vavilala respond to my comments on their manuscript published in Neurosurgery. I greatly appreciate and welcome this initiative as it provides a forum for scientific debate and discussion, which are so important to advance our knowledge. The authors are completely correct in emphasizing that they reported a lower incidence of intracranial pressure monitoring in infants (children ,1 year of age) compared with older children. With regard to the issues of adjustment for case mix and potential confounding of the Glasgow Coma Scale, more debate is possible. Very limited adjustment for case mix might even be discouraged compared with no adjustment because it falsely raises the perception that the reported results are not influenced by other confounding factors. I fail to understand how pediatric subjects with a Glasgow Motor Coma Scale of 3 can be assigned an Abbreviated Injury Score (AIS) of 3 (warranting hospital but not intensive care unit admission) or can even be categorized as possibly having moderate traumatic brain injury. These details are, however, of relative insignificance compared with the larger and much more important issue that I attempted to raise, namely the substantial limitations in analyzing and interpreting data obtained from registry databases. Increasingly, we are seeing reports in the medical literature based on analysis of registry data, often not collected for scientific but rather for administrative reasons. Undoubtedly, parties contributing to registry data will make all efforts to ensure the highest quality of data, but this does not alleviate the fundamental concern—as mentioned by the authors themselves—about absence of important clinical information in the registry database. In the particular case of the National Trauma Data Bank, for example, data on pupillary examinations, physiological status, presence or absence of mass lesions, and indications for performing a craniectomy were lacking. Although I would not wish to detract from the importance of registry data for capturing a global picture of care and for benchmarking quality of care at an aggregate level, we should be careful not to expect too much of registry data from a scientific perspective and not try to answer questions that require more granular clinical data collection. Both registry and detailed data collection should be seen in concert, so that the internal validity and generalizability of the patient cohort with more detailed data can be determined from comparison with the registry data.
Disclosure The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
William Van Cleve Monica S. Vavilala Seattle, Washington
1. Cleve WV, Kernic MA, Ellenbogen RG, et al. National variability in intracranial pressure monitoring and craniotomy for children with moderate to severe traumatic brain injury. Neurosurgery. 2013;73(5):746-752. doi: 10.1227/NEU.0000000000000097. 2. Bennett TD, Riva-Cambrin J. Variation in intracranial pressure monitoring and outcomes in pediatric traumatic brain injury. Arch Pediatr Adolesc Med. 2012;166 (7):641-647. doi: 10.1001/archpediatrics.2012.322. 3. Morris KP, Forsyth RJ, Parslow RC, Tasker RC, Hawley CA. Intracranial pressure complicating severe traumatic brain injury in children: monitoring and management. Intensive Care Med. 2006;32(10):1606-1612. doi: 10.1007/s00134-006-0285-4. 10.1227/NEU.0000000000000272
E456 | VOLUME 74 | NUMBER 4 | APRIL 2014
www.neurosurgery-online.com
Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited.
CORRESPONDENCE
Reply to the Comment on the Article “National Variability in Intracranial Pressure Monitoring and Craniotomy for Children With Moderate to Severe Traumatic Brain Injury”
In Reply: Reply to the Comment on the Article “National Variability in Intracranial Pressure Monitoring and Craniotomy for Children With Moderate to Severe Traumatic Brain Injury”
After reading Dr Maas' comment regarding our recent article1 in Neurosurgery, we wish to make a few brief comments. With regard to the assertion that we reported a lower incidence of intracranial pressure monitoring (ICPM) in children aged 0 to 5 years: in fact, we reported a lower incidence of ICPM in infants (children aged ,1 year) in comparison with older children. The epidemiological importance of this finding, its persistent appearance in the literature,2,3 and the potential relevance for patient care all necessitate clarity in statement and the understanding of this distinction. Regarding the comment that adjustment for case mix between centers “was not possible” in our study: we believe that a distinction should be drawn between the lack of adjustment and the potential for incomplete adjustment. Although we would agree that the potential exists for incomplete adjustment in our work, the same is true for any nonrandomized study. Finally, with regard to the potential confounding of the Glasgow Coma Scale by sedation and neuromuscular blockade: with the use of limited clinical data, we sought to define a group of children with moderate or severe injury in order to examine the use of ICPM and craniotomy in those most likely to receive it. As stated in our methods, we performed a sensitivity analysis to examine the potential impact of sedation or paralytics on our results, and we found none.
In their Letter to the Editor, Drs Van Cleve and Vavilala respond to my comments on their manuscript published in Neurosurgery. I greatly appreciate and welcome this initiative as it provides a forum for scientific debate and discussion, which are so important to advance our knowledge. The authors are completely correct in emphasizing that they reported a lower incidence of intracranial pressure monitoring in infants (children ,1 year of age) compared with older children. With regard to the issues of adjustment for case mix and potential confounding of the Glasgow Coma Scale, more debate is possible. Very limited adjustment for case mix might even be discouraged compared with no adjustment because it falsely raises the perception that the reported results are not influenced by other confounding factors. I fail to understand how pediatric subjects with a Glasgow Motor Coma Scale of 3 can be assigned an Abbreviated Injury Score (AIS) of 3 (warranting hospital but not intensive care unit admission) or can even be categorized as possibly having moderate traumatic brain injury. These details are, however, of relative insignificance compared with the larger and much more important issue that I attempted to raise, namely the substantial limitations in analyzing and interpreting data obtained from registry databases. Increasingly, we are seeing reports in the medical literature based on analysis of registry data, often not collected for scientific but rather for administrative reasons. Undoubtedly, parties contributing to registry data will make all efforts to ensure the highest quality of data, but this does not alleviate the fundamental concern—as mentioned by the authors themselves—about absence of important clinical information in the registry database. In the particular case of the National Trauma Data Bank, for example, data on pupillary examinations, physiological status, presence or absence of mass lesions, and indications for performing a craniectomy were lacking. Although I would not wish to detract from the importance of registry data for capturing a global picture of care and for benchmarking quality of care at an aggregate level, we should be careful not to expect too much of registry data from a scientific perspective and not try to answer questions that require more granular clinical data collection. Both registry and detailed data collection should be seen in concert, so that the internal validity and generalizability of the patient cohort with more detailed data can be determined from comparison with the registry data.
Disclosure The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
William Van Cleve Monica S. Vavilala Seattle, Washington
1. Cleve WV, Kernic MA, Ellenbogen RG, et al. National variability in intracranial pressure monitoring and craniotomy for children with moderate to severe traumatic brain injury. Neurosurgery. 2013;73(5):746-752. doi: 10.1227/NEU.0000000000000097. 2. Bennett TD, Riva-Cambrin J. Variation in intracranial pressure monitoring and outcomes in pediatric traumatic brain injury. Arch Pediatr Adolesc Med. 2012;166 (7):641-647. doi: 10.1001/archpediatrics.2012.322. 3. Morris KP, Forsyth RJ, Parslow RC, Tasker RC, Hawley CA. Intracranial pressure complicating severe traumatic brain injury in children: monitoring and management. Intensive Care Med. 2006;32(10):1606-1612. doi: 10.1007/s00134-006-0285-4. 10.1227/NEU.0000000000000272
E456 | VOLUME 74 | NUMBER 4 | APRIL 2014
www.neurosurgery-online.com
Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited.
