J Trauma Acute Care Surg Volume 76, Number 5
the effects of supplemental oxygen on postoperative nausea and vomiting, the control for inspired oxygen concentration was 30% for 9 of 10 cited studies, just as in our study. An inspired oxygen concentration of 30% was also the control level for FIO2 in all 10 previous studies investigating the effect of supplemental oxygen on surgical site infection, as cited by Meyhoff et al.5 All these data indicate that FIO2 of approximately 0.30 is commonly used in patients like those in our study. We agree that as with every intervention in medicine, some concern exists regarding safety, and we appreciate your addition to the discussion of concern regarding increased mortality and perioperative oxygen brought up by the recent post hoc follow-up study conducted by the PROXI Trial Group and presented by Meyhoff et al.5 However, we disagree with your interpretation of the PROXI trial. As stated in the last sentence of the abstract of that study (and elsewhere in the article), the finding of increased mortality with high perioperative oxygen was not found in ‘‘noncancer patients.’’ Orthopedic fracture surgery obviously is noncancer surgery, so a concern of increased mortality is not supported by this citation. Furthermore, as cited in the Discussion section of that article, an analysis of ‘‘10 trials investigating 80% versus 30% perioperative oxygen’’ found no difference in 30-day mortality rates (1.4% vs. 1.2%, n = 4,544). The authors therefore wrote that it is ‘‘surprising to find a significantly increased mortality in our 80% oxygen group after 2.3 years’’ and believe that this ‘‘does not appear to be related to the immediate postoperative harmI from atelectasis and respiratory failure’’ but might be related to ‘‘different mechanisms, specifically in cancer patients.’’ We do agree with you, Dr. Pisano, that oxygen delivery and use are the primary factors for ultimately determining the efficacy of oxygen at the tissue level. The orthopedic patients in our study typically had tourniquets elevated to the surgical sites for approximately 2 hours, which further complicates the situation and is one of several factors that make orthopedic fracture surgery different from previously studied surgeries. Laboratory values commonly followed up to assess the adequacy of oxygen delivery and use, such as hemoglobin, cardiac index, oxygen saturation, mixed venous oxygen saturation (SVO2), central venous oxygen saturation (ScVO2), stroke volume index, stroke volume variation, partial pressure of arterial oxygen (PaO2), serum lactate, base deficit, and tissue oxygen saturation (StO2), are values that reflect systemic changes, not regional or localized changes, in tissue oxygenation. Even the use of gastric tonometry, near-infrared spectroscopy, and urinary partial pressure of oxygen (PO2) does not reflect localized changes in tissue dysoxia. However, adequate monitoring to maintain
Letters to the Editor
appropriate oxygen delivery and use, as is commonly conducted with trauma resuscitation, cardiac surgical procedures, and complex trauma orthopedic procedures, is not common with fracture surgery and would be a substantial change from current practice in North America. This is why the much simpler intervention of increasing FIO2 is so appealing. Finally, we respectfully disagree with your conclusion that our study should not be taken as a sign for further research. As stated in our article, if the results of our pilot study held up in a larger cohort, we would have demonstrated a large (46%, p = 0.17) reduction in surgical site infection rate by using a universally available, low-cost, low-risk technique. Therefore, we believe it is important for us to further investigate this technique considering that the public health consequences of such an intervention could be important if proved to be true. We currently are conducting a larger US government-funded (Department of Defense OR110123-W81XWH-12-1-0588) multicenter randomized trial based on this pilot studyVthrough the Major Extremity Trauma Research Consortium (METRC)Vand hope to definitively answer this question in the domain of orthopedic fracture surgery in the next few years. *The authors declare no conflicts of interest.
Robert V. O’Toole, MD Department of Orthopedics R Adams Cowley Shock Trauma Center University of Maryland Baltimore, MD
Robert Sikorski, MD Department of Anesthesiology University of Maryland School of Medicine Section Trauma Anesthesiology R Adams Cowley Shock Trauma Center Baltimore, MD
Renan C. Castillo, PhD Department of Health Policy and Management Johns Hopkins Bloomberg School of Public Health Baltimore, MD
Ebrahim Paryavi, MD, MPH Department of Orthopedics R Adams Cowley Shock Trauma Center University of Maryland Baltimore, MD
Alec Stall, MD, MPH North Central Baptist Hospital and Pediatric Orthopedics at Stone Oak San Antonio, TX
REFERENCES 1. Blum JM, Fetterman DM, Park PK, et al. A description of intraoperative ventilator management and ventilation strategies in hypoxic patients. Anesth Analg. 2010;110(6): 1616Y1622.
2. Kabon B, Kurz A. Optimal perioperative oxygen administration. Curr Opin Anaesthesiol. 2006;19(1):11Y18. 3. Meyhoff CS, Staehr AK, Rasmussen LS. Rational use of oxygen in medical disease and anesthesia. Curr Opin Anesthesiol. 2012; 25(3):363Y370. 4. Orhan-Sungur M, Kranke P, Sessler D, Apfel CC. Does supplemental oxygen reduce postoperative nausea and vomiting? A meta-analysis of randomized controlled trials. Anesth Analg. 2008; 106(6):1733Y1738. 5. Meyhoff CS, Jorgensen LN, Wetterslev J, et al PROXI Trial Group. Increased long-term mortality after a high perioperative inspiratory oxygen fraction during abdominal surgery: Follow-up of a randomized clinical trial. Anesth Analg. 2012; 115(4):849Y854.
The trauma safety net hospital under the Affordable Care Act: Will it survive? To the Editor: he article, ‘‘The trauma safety net hospital under the Affordable Care Act: Will it survive?,’’ implies that the Affordable Care Act provides funding through grants, compensates trauma centers for losses from uncompensated care, and provides emergency awards to centers at risk of closure.1 Unfortunately, the Congress has yet to provide appropriated funding for these important programs that were included in the law. Therefore, trauma centers and systems continue to lack the funding they desperately need. A number of organizations in the trauma community including the Trauma Center Association of America worked collaboratively to include these trauma programs to support trauma centers and systems and improve access to trauma care in the Affordable Care Act. It has been an uphill battle, but we are continuing to work on getting them funded by the Congress. The importance of trauma systems in expediting patient care and transport cannot be overstated; however, there has been no dedicated federal funding since 2005 to support their continued development and implementation. We share the authors’ concerns about the impact of disproportionate share hospital cuts to hospitals with trauma centers referenced in the article. We are also concerned about a recent proposal from the Centers of Medicare and Medicaid Services in the proposed Medicare and Medicaid Hospital Outpatient Prospective Payment rule to consolidate all
T
* 2014 Lippincott Williams & Wilkins
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
1333
J Trauma Acute Care Surg Volume 76, Number 5
Letters to the Editor
emergency department codes into one code. This proposal, given the highly complex nature of trauma care relative to emergency department services generally, would disproportionately impair trauma centers’ ability to provide an appropriate level of care to patients with traumatic injury and would significantly impact trauma centers financially. The challenges facing trauma centers, physicians, nurses, and the entire trauma team are profound. Federal funding and an adequate reimbursement are necessary to ensure access to lifesaving trauma care for all Americans. *The author declares no conflict of interest.
Blaine L. Enderson, MD Division of Trauma and Critical Care University of Tennessee Knoxville, TN
REFERENCE 1. Khoury AL, Charles AG, Sheldon GF, et al. The trauma safety-net hospital under the Affordable Care Act: will it survive? J Trauma Acute Care Surg. 2013;75(3):512Y5.
Nonoperative management of splenic trauma should be approached with caution in the setting of traumatic brain injury To the Editor: e read with great interest the recent publication by Teixeira et al.1 The current article describes a retrospective study performed on a cohort extracted from the National Trauma Data Bank. The authors sought to characterize the mortality outcome of splenectomy in patients with concomitant traumatic brain injury (TBI). Patients with moderate-to-severe blunt head injury and those with splenic injury were included in the study. Careful scrutiny of the cohort characteristics reveals important differences between the two populations1 (Tables 1 and 2). Those that underwent splenectomy were more likely to be hemodynamically unstable on arrival. Absence of a base deficit from the analysis limits the reader’s ability to appreciate the degree and persistence of hypotension as well as estimated mortality. Moreover, those who underwent splenectomy were more likely to have concomitant severe lifethreatening intra-abdominal injuries.
W
1334
In the unadjusted outcome measures, patients with severe TBI seemed to fair better when nonoperative splenic management (NOM) was pursued (16.9% vs. 10.1% mortality, p G 0.001). Given the previously discussed cohort differences, the observed increased risk of death in the splenectomy group with severe TBI is not unanticipated. Furthermore, despite the purported mortality benefit, hospital and intensive care unit (ICU) lengths of stay as well as ventilator days seemed to be negatively corelated with NOM. Although the adjusted outcome measures seem to support a mortality benefit in both the moderate and severe TBI group when NOM was elected (odds ratio, 2.43 and 1.49; p = 0.008 and p = 0.036 respectively), different logistic regression models were used to reach these conclusions. It is unclear why different models should be used to investigate subgroups within each arm. Unchanged is the apparent negative correlation with hospital and ICU lengths of stay as well as ventilator days. Of particular interest in the present study given the inability to readily interpret the increased mortality rate in the splenectomy group is the neurologic outcome of patients in these two groups. In a recent systematic review of the literature, Injury Severity Score (ISS) greater than 25 and splenic injury grade of 3 or higher were associated with failure of NOM.2 It is reasonable to hypothesize that this subpopulation of critically injured patients will exhibit increased hemodynamic instability and need for blood transfusion. Recent studies investigating the role of intermittent hypotension and blood transfusion in those with isolated TBI have demonstrated an increased morbidity and mortality.3,4 Together, these data suggest that the very population proposed to have a decreased mortality rate may in fact have a poorer neurologic outcome. Limitations of the National Trauma Data Bank preclude further investigation needed to determine if the increased hospital or ICU lengths of stay are reflective of this possibility. Finally, several groups have found that TBI may independently predict the failure of NOM,5 further complicating interpretation of the results put forth by Teixeira et al.1 In summary, given the significant differences between the two study arms, we question the validity of the authors’ conclusion that ‘‘splenectomy was independently associated with increased mortality in patients with moderate or severe TBI.’’ Furthermore, the neurologic outcome in these survivors remains unknown. While the current findings are provocative, further study is needed to clarify the impact of the interdependent variables of hemodynamics, injury severity, as well as splenic injury and TBI. Given the preponderance of evidence, the routine implementation of aggressive attempts of splenic preservation with concomitant TBI
should be deferred until additional investigation is undertaken. *The authors declare no conflicts of interest.
Joseph S. Hanna, MD, PhD Vicente H. Gracias, MD Division of Acute Care Surgery Department of Surgery Rutgers-Robert Wood Johnson Medical School New Brunswick, NJ
REFERENCES 1. Teixeira PG, Karamanos E, Okoye OT, et al. Splenectomy in patients with raumatic brain injury: protective or harmful? A National Trauma Data Bank analysis. J Trauma Acute Care Surg. 2013;75:596Y601. 2. Olthof DC, Joosse P, van der Vlies CH, et al. Prognostic factors for failure of nonoperative management in adults with blunt splenic injury: a systematic review. J Trauma Acute Care Surg. 2013;74:546Y557. 3. Brenner M, Stein DM, Hu PF, et al. Traditional systolic blood pressure targets underestimate hypotension-induced secondary brain injury. J Trauma Acute Care Surg. 2012;72:1135Y1139. 4. Elterman J, Brasel K, Brown S, et al. Transfusion of red blood cells in patients with a prehospital Glasgow Coma Scale score of 8 or less and no evidence of shock is associated with worse outcomes. J. Trauma Acute Care Surg. 2013;75:8Y14; discussion 14. 5. Velmahos GC, Zacharias N, Emhoff TA, et al. Management of the most severely injured spleen: a multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Arch Surg. 2010;145: 456Y460.
Spinal cord injury without radiologic abnormality in children imaged with magnetic resonance imaging To the Editor: e congratulate Dr. Mahajan and colleagues on their article comparing the clinical characteristics and outcomes of children with spinal cord injury without radiologic abnormality (SCIWORA) relative to the presence or absence of abnormalities on magnetic resonance imaging (MRI).1 In this retrospective multicenter study, 69 children presenting with a clinicoradiologic mismatch and treated at 17 contributing emergency departments in the United States were analyzed. One of the key findings is the predominance of normal MRI scan findings in
W
* 2014 Lippincott Williams & Wilkins
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
the effects of supplemental oxygen on postoperative nausea and vomiting, the control for inspired oxygen concentration was 30% for 9 of 10 cited studies, just as in our study. An inspired oxygen concentration of 30% was also the control level for FIO2 in all 10 previous studies investigating the effect of supplemental oxygen on surgical site infection, as cited by Meyhoff et al.5 All these data indicate that FIO2 of approximately 0.30 is commonly used in patients like those in our study. We agree that as with every intervention in medicine, some concern exists regarding safety, and we appreciate your addition to the discussion of concern regarding increased mortality and perioperative oxygen brought up by the recent post hoc follow-up study conducted by the PROXI Trial Group and presented by Meyhoff et al.5 However, we disagree with your interpretation of the PROXI trial. As stated in the last sentence of the abstract of that study (and elsewhere in the article), the finding of increased mortality with high perioperative oxygen was not found in ‘‘noncancer patients.’’ Orthopedic fracture surgery obviously is noncancer surgery, so a concern of increased mortality is not supported by this citation. Furthermore, as cited in the Discussion section of that article, an analysis of ‘‘10 trials investigating 80% versus 30% perioperative oxygen’’ found no difference in 30-day mortality rates (1.4% vs. 1.2%, n = 4,544). The authors therefore wrote that it is ‘‘surprising to find a significantly increased mortality in our 80% oxygen group after 2.3 years’’ and believe that this ‘‘does not appear to be related to the immediate postoperative harmI from atelectasis and respiratory failure’’ but might be related to ‘‘different mechanisms, specifically in cancer patients.’’ We do agree with you, Dr. Pisano, that oxygen delivery and use are the primary factors for ultimately determining the efficacy of oxygen at the tissue level. The orthopedic patients in our study typically had tourniquets elevated to the surgical sites for approximately 2 hours, which further complicates the situation and is one of several factors that make orthopedic fracture surgery different from previously studied surgeries. Laboratory values commonly followed up to assess the adequacy of oxygen delivery and use, such as hemoglobin, cardiac index, oxygen saturation, mixed venous oxygen saturation (SVO2), central venous oxygen saturation (ScVO2), stroke volume index, stroke volume variation, partial pressure of arterial oxygen (PaO2), serum lactate, base deficit, and tissue oxygen saturation (StO2), are values that reflect systemic changes, not regional or localized changes, in tissue oxygenation. Even the use of gastric tonometry, near-infrared spectroscopy, and urinary partial pressure of oxygen (PO2) does not reflect localized changes in tissue dysoxia. However, adequate monitoring to maintain
Letters to the Editor
appropriate oxygen delivery and use, as is commonly conducted with trauma resuscitation, cardiac surgical procedures, and complex trauma orthopedic procedures, is not common with fracture surgery and would be a substantial change from current practice in North America. This is why the much simpler intervention of increasing FIO2 is so appealing. Finally, we respectfully disagree with your conclusion that our study should not be taken as a sign for further research. As stated in our article, if the results of our pilot study held up in a larger cohort, we would have demonstrated a large (46%, p = 0.17) reduction in surgical site infection rate by using a universally available, low-cost, low-risk technique. Therefore, we believe it is important for us to further investigate this technique considering that the public health consequences of such an intervention could be important if proved to be true. We currently are conducting a larger US government-funded (Department of Defense OR110123-W81XWH-12-1-0588) multicenter randomized trial based on this pilot studyVthrough the Major Extremity Trauma Research Consortium (METRC)Vand hope to definitively answer this question in the domain of orthopedic fracture surgery in the next few years. *The authors declare no conflicts of interest.
Robert V. O’Toole, MD Department of Orthopedics R Adams Cowley Shock Trauma Center University of Maryland Baltimore, MD
Robert Sikorski, MD Department of Anesthesiology University of Maryland School of Medicine Section Trauma Anesthesiology R Adams Cowley Shock Trauma Center Baltimore, MD
Renan C. Castillo, PhD Department of Health Policy and Management Johns Hopkins Bloomberg School of Public Health Baltimore, MD
Ebrahim Paryavi, MD, MPH Department of Orthopedics R Adams Cowley Shock Trauma Center University of Maryland Baltimore, MD
Alec Stall, MD, MPH North Central Baptist Hospital and Pediatric Orthopedics at Stone Oak San Antonio, TX
REFERENCES 1. Blum JM, Fetterman DM, Park PK, et al. A description of intraoperative ventilator management and ventilation strategies in hypoxic patients. Anesth Analg. 2010;110(6): 1616Y1622.
2. Kabon B, Kurz A. Optimal perioperative oxygen administration. Curr Opin Anaesthesiol. 2006;19(1):11Y18. 3. Meyhoff CS, Staehr AK, Rasmussen LS. Rational use of oxygen in medical disease and anesthesia. Curr Opin Anesthesiol. 2012; 25(3):363Y370. 4. Orhan-Sungur M, Kranke P, Sessler D, Apfel CC. Does supplemental oxygen reduce postoperative nausea and vomiting? A meta-analysis of randomized controlled trials. Anesth Analg. 2008; 106(6):1733Y1738. 5. Meyhoff CS, Jorgensen LN, Wetterslev J, et al PROXI Trial Group. Increased long-term mortality after a high perioperative inspiratory oxygen fraction during abdominal surgery: Follow-up of a randomized clinical trial. Anesth Analg. 2012; 115(4):849Y854.
The trauma safety net hospital under the Affordable Care Act: Will it survive? To the Editor: he article, ‘‘The trauma safety net hospital under the Affordable Care Act: Will it survive?,’’ implies that the Affordable Care Act provides funding through grants, compensates trauma centers for losses from uncompensated care, and provides emergency awards to centers at risk of closure.1 Unfortunately, the Congress has yet to provide appropriated funding for these important programs that were included in the law. Therefore, trauma centers and systems continue to lack the funding they desperately need. A number of organizations in the trauma community including the Trauma Center Association of America worked collaboratively to include these trauma programs to support trauma centers and systems and improve access to trauma care in the Affordable Care Act. It has been an uphill battle, but we are continuing to work on getting them funded by the Congress. The importance of trauma systems in expediting patient care and transport cannot be overstated; however, there has been no dedicated federal funding since 2005 to support their continued development and implementation. We share the authors’ concerns about the impact of disproportionate share hospital cuts to hospitals with trauma centers referenced in the article. We are also concerned about a recent proposal from the Centers of Medicare and Medicaid Services in the proposed Medicare and Medicaid Hospital Outpatient Prospective Payment rule to consolidate all
T
* 2014 Lippincott Williams & Wilkins
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
1333
J Trauma Acute Care Surg Volume 76, Number 5
Letters to the Editor
emergency department codes into one code. This proposal, given the highly complex nature of trauma care relative to emergency department services generally, would disproportionately impair trauma centers’ ability to provide an appropriate level of care to patients with traumatic injury and would significantly impact trauma centers financially. The challenges facing trauma centers, physicians, nurses, and the entire trauma team are profound. Federal funding and an adequate reimbursement are necessary to ensure access to lifesaving trauma care for all Americans. *The author declares no conflict of interest.
Blaine L. Enderson, MD Division of Trauma and Critical Care University of Tennessee Knoxville, TN
REFERENCE 1. Khoury AL, Charles AG, Sheldon GF, et al. The trauma safety-net hospital under the Affordable Care Act: will it survive? J Trauma Acute Care Surg. 2013;75(3):512Y5.
Nonoperative management of splenic trauma should be approached with caution in the setting of traumatic brain injury To the Editor: e read with great interest the recent publication by Teixeira et al.1 The current article describes a retrospective study performed on a cohort extracted from the National Trauma Data Bank. The authors sought to characterize the mortality outcome of splenectomy in patients with concomitant traumatic brain injury (TBI). Patients with moderate-to-severe blunt head injury and those with splenic injury were included in the study. Careful scrutiny of the cohort characteristics reveals important differences between the two populations1 (Tables 1 and 2). Those that underwent splenectomy were more likely to be hemodynamically unstable on arrival. Absence of a base deficit from the analysis limits the reader’s ability to appreciate the degree and persistence of hypotension as well as estimated mortality. Moreover, those who underwent splenectomy were more likely to have concomitant severe lifethreatening intra-abdominal injuries.
W
1334
In the unadjusted outcome measures, patients with severe TBI seemed to fair better when nonoperative splenic management (NOM) was pursued (16.9% vs. 10.1% mortality, p G 0.001). Given the previously discussed cohort differences, the observed increased risk of death in the splenectomy group with severe TBI is not unanticipated. Furthermore, despite the purported mortality benefit, hospital and intensive care unit (ICU) lengths of stay as well as ventilator days seemed to be negatively corelated with NOM. Although the adjusted outcome measures seem to support a mortality benefit in both the moderate and severe TBI group when NOM was elected (odds ratio, 2.43 and 1.49; p = 0.008 and p = 0.036 respectively), different logistic regression models were used to reach these conclusions. It is unclear why different models should be used to investigate subgroups within each arm. Unchanged is the apparent negative correlation with hospital and ICU lengths of stay as well as ventilator days. Of particular interest in the present study given the inability to readily interpret the increased mortality rate in the splenectomy group is the neurologic outcome of patients in these two groups. In a recent systematic review of the literature, Injury Severity Score (ISS) greater than 25 and splenic injury grade of 3 or higher were associated with failure of NOM.2 It is reasonable to hypothesize that this subpopulation of critically injured patients will exhibit increased hemodynamic instability and need for blood transfusion. Recent studies investigating the role of intermittent hypotension and blood transfusion in those with isolated TBI have demonstrated an increased morbidity and mortality.3,4 Together, these data suggest that the very population proposed to have a decreased mortality rate may in fact have a poorer neurologic outcome. Limitations of the National Trauma Data Bank preclude further investigation needed to determine if the increased hospital or ICU lengths of stay are reflective of this possibility. Finally, several groups have found that TBI may independently predict the failure of NOM,5 further complicating interpretation of the results put forth by Teixeira et al.1 In summary, given the significant differences between the two study arms, we question the validity of the authors’ conclusion that ‘‘splenectomy was independently associated with increased mortality in patients with moderate or severe TBI.’’ Furthermore, the neurologic outcome in these survivors remains unknown. While the current findings are provocative, further study is needed to clarify the impact of the interdependent variables of hemodynamics, injury severity, as well as splenic injury and TBI. Given the preponderance of evidence, the routine implementation of aggressive attempts of splenic preservation with concomitant TBI
should be deferred until additional investigation is undertaken. *The authors declare no conflicts of interest.
Joseph S. Hanna, MD, PhD Vicente H. Gracias, MD Division of Acute Care Surgery Department of Surgery Rutgers-Robert Wood Johnson Medical School New Brunswick, NJ
REFERENCES 1. Teixeira PG, Karamanos E, Okoye OT, et al. Splenectomy in patients with raumatic brain injury: protective or harmful? A National Trauma Data Bank analysis. J Trauma Acute Care Surg. 2013;75:596Y601. 2. Olthof DC, Joosse P, van der Vlies CH, et al. Prognostic factors for failure of nonoperative management in adults with blunt splenic injury: a systematic review. J Trauma Acute Care Surg. 2013;74:546Y557. 3. Brenner M, Stein DM, Hu PF, et al. Traditional systolic blood pressure targets underestimate hypotension-induced secondary brain injury. J Trauma Acute Care Surg. 2012;72:1135Y1139. 4. Elterman J, Brasel K, Brown S, et al. Transfusion of red blood cells in patients with a prehospital Glasgow Coma Scale score of 8 or less and no evidence of shock is associated with worse outcomes. J. Trauma Acute Care Surg. 2013;75:8Y14; discussion 14. 5. Velmahos GC, Zacharias N, Emhoff TA, et al. Management of the most severely injured spleen: a multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Arch Surg. 2010;145: 456Y460.
Spinal cord injury without radiologic abnormality in children imaged with magnetic resonance imaging To the Editor: e congratulate Dr. Mahajan and colleagues on their article comparing the clinical characteristics and outcomes of children with spinal cord injury without radiologic abnormality (SCIWORA) relative to the presence or absence of abnormalities on magnetic resonance imaging (MRI).1 In this retrospective multicenter study, 69 children presenting with a clinicoradiologic mismatch and treated at 17 contributing emergency departments in the United States were analyzed. One of the key findings is the predominance of normal MRI scan findings in
W
* 2014 Lippincott Williams & Wilkins
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
