Outcomes of Open vs Endoscopic Skull Base Surgery in Patients 70 Years or Older | Otolaryngology | JAMA Otolaryngology–Head & Neck Surgery | JAMA Network
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Figure.  Distribution of Age at Time of Skull Base Surgery Among Patients 70 Years or Older
Distribution of Age at Time of Skull Base Surgery Among Patients 70 Years or Older
Table 1.  Baseline Characteristics and Skull Base Abnormality Among 219 Patients
Baseline Characteristics and Skull Base Abnormality Among 219 Patients
Table 2.  Operative Outcomes by Agea
Operative Outcomes by Agea
Table 3.  Operative Outcomes for Open vs Endoscopic Surgical Approaches to the Skull Base
Operative Outcomes for Open vs Endoscopic Surgical Approaches to the Skull Base
Table 4.  Operative Outcomes for Benign vs Malignant Skull Base Abnormality
Operative Outcomes for Benign vs Malignant Skull Base Abnormality
1.
Dutta  R, Dubal  PM, Svider  PF, Liu  JK, Baredes  S, Eloy  JA.  Sinonasal malignancies: a population-based analysis of site-specific incidence and survival.  Laryngoscope. 2015;125(11):2491-2497. doi:10.1002/lary.25465PubMedGoogle ScholarCrossref
2.
Roxbury  CR, Ishii  M, Richmon  JD, Blitz  AM, Reh  DD, Gallia  GL.  Endonasal endoscopic surgery in the management of sinonasal and anterior skull base malignancies.  Head Neck Pathol. 2016;10(1):13-22. doi:10.1007/s12105-016-0687-8PubMedGoogle ScholarCrossref
3.
Snyderman  CH, Carrau  RL, Kassam  AB,  et al.  Endoscopic skull base surgery: principles of endonasal oncological surgery.  J Surg Oncol. 2008;97(8):658-664. doi:10.1002/jso.21020PubMedGoogle ScholarCrossref
4.
Rawal  RB, Farzal  Z, Federspiel  JJ, Sreenath  SB, Thorp  BD, Zanation  AM.  Endoscopic resection of sinonasal malignancy: a systematic review and meta-analysis.  Otolaryngol Head Neck Surg. 2016;155(3):376-386. doi:10.1177/0194599816646968PubMedGoogle ScholarCrossref
5.
Farquhar  D, Kim  L, Worrall  D,  et al.  Propensity score analysis of endoscopic and open approaches to malignant paranasal and anterior skull base tumor outcomes.  Laryngoscope. 2016;126(8):1724-1729. doi:10.1002/lary.25885PubMedGoogle ScholarCrossref
6.
Buchmann  L, Larsen  C, Pollack  A, Tawfik  O, Sykes  K, Hoover  LA.  Endoscopic techniques in resection of anterior skull base/paranasal sinus malignancies.  Laryngoscope. 2006;116(10):1749-1754. doi:10.1097/01.mlg.0000233528.99562.c2PubMedGoogle ScholarCrossref
7.
Ganly  I, Patel  SG, Singh  B,  et al.  Complications of craniofacial resection for malignant tumors of the skull base: report of an international collaborative study.  Head Neck. 2005;27(6):445-451. doi:10.1002/hed.20166PubMedGoogle ScholarCrossref
8.
Deiner  S, Westlake  B, Dutton  RP.  Patterns of surgical care and complications in elderly adults.  J Am Geriatr Soc. 2014;62(5):829-835. doi:10.1111/jgs.12794PubMedGoogle ScholarCrossref
9.
Ganly  I, Patel  SG, Singh  B,  et al.  Craniofacial resection for malignant tumors involving the skull base in the elderly: an international collaborative study.  Cancer. 2011;117(3):563-571. doi:10.1002/cncr.25390PubMedGoogle ScholarCrossref
10.
Ganly  I, Gross  ND, Patel  SG, Bilsky  MH, Shah  JP, Kraus  DH.  Outcome of craniofacial resection in patients 70 years of age and older.  Head Neck. 2007;29(2):89-94. doi:10.1002/hed.20487PubMedGoogle ScholarCrossref
11.
Hentschel  SJ, Nader  R, Suki  D, Dastgir  A, Callender  DL, DeMonte  F.  Craniofacial resections in the elderly: an outcome study.  J Neurosurg. 2004;101(6):935-943. doi:10.3171/jns.2004.101.6.0935PubMedGoogle ScholarCrossref
12.
Harris  PA, Taylor  R, Thielke  R, Payne  J, Gonzalez  N, Conde  JG.  Research electronic data capture (REDCap)—a metadata-driven methodology and workflow process for providing translational research informatics support.  J Biomed Inform. 2009;42(2):377-381. doi:10.1016/j.jbi.2008.08.010PubMedGoogle ScholarCrossref
Original Investigation
October 2018

Outcomes of Open vs Endoscopic Skull Base Surgery in Patients 70 Years or Older

Author Affiliations
  • 1Medical student, UNC School of Medicine, University of North Carolina at Chapel Hill
  • 2Department of Otolaryngology–Head and Neck Surgery, University of North Carolina Memorial Hospitals, Chapel Hill
  • 3Department of Otolaryngology–Head and Neck Surgery, University of North Carolina at Chapel Hill
  • 4Department of Neurosurgery, University of North Carolina at Chapel Hill
JAMA Otolaryngol Head Neck Surg. 2018;144(10):923-928. doi:10.1001/jamaoto.2018.1948
Key Points

Questions  What are the general skull base surgery outcomes in patients 70 years or older, and are patient age, disease process, and surgical approach associated with increased intraoperative or postoperative complications in this population?

Findings  This cohort study found no clinically meaningful difference in complications from skull base surgery with increasing age, endoscopic vs open approach, or benign vs malignant disease in patients 70 years or older.

Meaning  Skull base surgery is a safe option in persons 70 years or older, with similar outcomes across older age ranges, surgical approaches, and pathologic findings.

Abstract

Importance  The use of skull base surgery in patients 70 years or older is increasing, but its safety in this age group has not been evaluated to date.

Objectives  To describe outcomes in a cohort of patients 70 years or older undergoing skull base surgery and to evaluate whether age, type of disease process, and approach (endoscopic vs traditional open surgery) are associated with increased intraoperative and postoperative complications in this population.

Design, Setting, and Participants  This retrospective cohort study analyzed a population-based sample of 219 patients 70 years or older from a database of 1720 patients who underwent skull base surgery at University of North Carolina Hospitals, Chapel Hill, a tertiary referral center, between October 2007 and June 2017. Data were collected from June 2016 to July 2017 and analyzed in July 2017 and August 2017.

Exposure  Skull base surgery.

Main Outcomes and Measures  Data collected included demographic characteristics, surgical approach, and disease process. Intraoperative findings and postoperative complications were analyzed by age, surgical approach, and malignancy status.

Results  Of the 219 patients, 166 were aged 70.0 to 79.9 years and 53 patients were older than 80 years (mean [SD] age, 76.4 [4.7] years); 120 (54.8%) were men and 160 (73.7%) were white. There were 161 (73.5%) endoscopic and 58 (26.5%) open operations. The most common pathologic processes among the 219 patients were nonsellar malignant (81 [37.0%]), nonsellar benign (53 [24.2%]), and pituitary (49 [22.4%]) tumors. The most common intraoperative and postoperative complications were intraoperative major bleeding (5 of 219 patients [2.3%]) and postoperative bleeding (9 [4.1%]). Thirty-day mortality was zero. There was no clinically meaningful difference in complications between patients aged 70.0 to 79.9 years vs those older than 80 years, endoscopic vs open surgery, or benign vs malignant neoplasms. Specifically, between the endoscopic and open surgery groups, there was no difference in intraoperative major bleeding (3.9%; 95% CI, −0.7% to 12.9%), postoperative cerebrospinal fluid leak (−0.6%; 95% CI, −3.4% to 5.6%), or postoperative bleeding (1.5%; 95% CI, −3.9% to 10.6%).

Conclusions and Relevance  Skull base surgery is a safe option in persons 70 years or older, with similar outcomes across age ranges, surgical approaches, and disease processes.

Introduction

A variety of pathologic processes may involve or extend to the anterior skull base, a complex structural boundary separating the intracranial from the sinonasal and facial regions. Although rare in the general population, the most common skull base lesions at our institution include nonsellar benign or malignant tumors and benign pituitary lesions.1 Resection of skull base neoplasm may be accomplished via traditional open, endoscopic, or combined surgical approaches.2 The endoscopic endonasal approach has become the standard of care because it provides minimally invasive access to a large portion of the skull base, including anterior and middle cranial fossae and sellae and suprasellar and parasellar regions, and it has been associated with lower surgical morbidity and shorter length of hospitalization.3-6 However, the complication rate associated with endoscopic endonasal resection of some skull base tumors in previous studies is not insignificant, with estimates of postoperative mortality of 3% to 5% and postoperative complications up to 36% to 42% in adults.7

The use of skull base surgery in patients 70 years or older, a medically challenging population, is becoming increasingly common, particularly with the increased use of minimally invasive techniques. With regard to general surgical procedures, it is well documented that patient age of 70 years or older is associated with increased perioperative complications compared with younger patient age.8 However, the safety of skull base surgery, specifically in the population of persons older than 70 years, has not been thoroughly evaluated in the existing literature. Few studies have analyzed smaller cohorts of patients 70 years or older who underwent craniofacial surgery. Ganly et al9 analyzed a 170-patient, multi-institutional cohort of patients 70 years or older with malignant tumors who underwent craniofacial surgery and found higher postoperative complication rates in these patients than in younger patients; however, an analysis of outcomes comparing endoscopic and open approaches was not performed. In addition, the data from that study were collected before endoscopic surgery was widely used for skull base neoplasms. In a different study, Ganly et al10 found similar results in a smaller cohort of 36 similarly aged patients who underwent skull base surgery. Hentschel et al11 found increased perioperative complications in a cohort of 28 older patients compared with a younger group.

The present study is the first single-institution study, to our knowledge, to analyze and conduct detailed subanalyses in a cohort of more than 200 patients 70 years or older who have undergone skull base surgery for a variety of benign and malignant entities. The aims of this study were to describe outcomes in this cohort; to evaluate whether age, pathologic process, and surgical approach are associated with increased intraoperative and postoperative complications; and to analyze other factors potentially associated with increased perioperative complications.

Methods
Study Design and Participants

A database of 1720 patients who underwent surgery that involved the anterior or lateral bony skull base between October 2007 and June 2017 at the University of North Carolina Hospitals, Chapel Hill, a tertiary referral medical center, was analyzed. Data were collected from June 2016 to July 2017 and analyzed in July 2017 and August 2017. The University of North Carolina Hospitals’ institutional review board approved access to the database and waived informed consent for data collection. Two hundred nineteen patients met the criterion of age 70 years or older.

Data Sources and Measurements

Retrospective review of the electronic medical record was used to collect additional data not present in the database for each patient. Data collection was performed using existing electronic medical records. Data were recorded in a Health Insurance Portability and Accountability Act–compliant online database. Demographic data collected included patient age, sex, race, ethnicity, past nasal surgery, past chemotherapy or radiotherapy, and American Society of Anesthesiologists physical status classification as a surrogate for medical comorbidities. Race and ethnicity were defined only by electronic medical record categories, not by the investigator, and these data were collected and analyzed to comprehensively assess any patient factors associated with operative outcomes.

Data on intraoperative findings, postoperative outcomes, and final pathologic determination for each patient were collected from clinic and operative notes in the electronic medical record. Final pathologic determination was obtained from final surgical pathology reports. Pathologic findings were categorized as pituitary (sellar), skull base, encephalocele or cerebrospinal fluid leak, nonsellar benign tumor, malignant tumor, and inflammatory process. The inflammatory process category included mucocele, allergic fungal sinusitis, invasive fungal sinusitis, and osteoradionecrosis. Reports from preoperative radiologic imaging were reviewed to identify the size of pituitary lesions and encephaloceles, if present.

Operative notes were used to collect information about surgical approach, anatomic location, and intraoperative findings such as cerebrospinal fluid leak, dural defect size, placement of external ventricular drain or lumbar drain, gross total resection, tracheostomy, and skull base reconstruction. Intraoperative complications were identified and classified as either systemic (anesthesia-related, cardiac, or pulmonary), hemorrhagic, or neurologic (nerve transection, brain extrusion, lumbar drain placement failure, cerebritis, or meningitis). Intraoperative major bleeding was defined as bleeding that was beyond the upper normal limit for skull base surgery requiring transfusion or other additional management, bleeding that was mentioned in the operative note, or both. Postoperative complications were also identified, including presence and management of cerebrospinal fluid leak, bleeding (including hematoma, epistaxis, and other surgical site bleeding requiring intervention), hospital readmission, cranial neuropathy, pneumocephalus, cerebrovascular event, flap failure, death, and early (<6 months postoperatively) or late (>6 months postoperatively) reoperation.

Quantitative Variables and Statistical Methods

Patient demographic characteristics, surgical approaches, lesion characteristics, and outcomes were analyzed using descriptive and quantitative statistics. Age younger than 80 years vs 80 years or older, open vs endoscopic approaches, and benign vs malignant disease were compared using effect size and 95% CI. Data were collected and stored in a customized REDCap skull base surgery database hosted at the University of North Carolina and analyzed with Stata, version 14.0 (StataCorp).12

Results
Participants

A total of 219 patients 70 years or older were analyzed, including 120 men (54.8%) and 99 women (45.2%). One hundred sixty-six patients (74.9%) were aged 70.0 to 79.9 years, and 53 (25.1%) were 80 years or older (Figure). The mean (SD) age was 76.4 (4.7) years, with a range of 70.0 to 87.9 years; 160 patients (73.7%) were white. There were 161 (73.5%) endoscopic operations and 58 (26.5%) that used an open approach. The most common pathologic conditions were nonsellar malignant tumor (81 [37.0%]), nonsellar benign tumor (53 [24.2%]), and pituitary (sellar) tumor (49 [22.4%]). Surgery involved the sella in 60 procedures (27.4%) and was nonsellar in 159 (72.6%). Of the endoscopic procedures, 126 (78.3%) were associated with benign pathologic findings, and 46 (79.3%) of open approaches were associated with malignant pathologic processes. See Table 1 for detailed patient demographic characteristics and surgical factors.

Outcomes

The most common intraoperative and postoperative complications were intraoperative major bleeding (5 of 219 patients [2.3%]) and postoperative bleeding (9 [4.1%]), respectively. There were no recorded cases of inadvertent cranial nerve loss, pneumocephalus, intraoperative myocardial infarction, pulmonary complications, or 30-day postoperative mortality. Based on the calculated 95% CI for each operative outcome event, we found no clinically meaningful difference in intraoperative or postoperative complications in patients aged 70.0 to 79.9 vs those older than 80 years, endoscopic vs open, or benign vs malignant pathologic group (Tables 2, 3, and 4). Specifically, between the endoscopic and open group, there was no clinically meaningful difference in intraoperative systemic complications (Table 3), intraoperative major bleeding (3.9%, 95% CI, −0.7% to 12.9%), postoperative cerebrospinal fluid leak (−0.6%, 95% CI, −3.4% to 5.6%), or postoperative bleed (1.5%, 95% CI, −3.9% to 10.6%).

Discussion

Although skull base surgery historically has rarely been performed in patients 70 years or older in the past owing to concern for relatively higher operative risk and poor outcomes, it is becoming increasingly common. However, the existing literature lacks sufficient evidence for the safety and feasibility of this surgery in patients 70 years or older. Specifically, to our knowledge, no data exist regarding preoperative factors and operative outcomes for subgroups within the 70 years or older patient demographic group. Older patients are often analyzed as a whole, with all patients older than 65 to 70 years grouped together. However, there may be significant differences in clinical and surgical factors between, for example, a 70-year-old and an 85-year-old patient. In addition, previous studies have not analyzed outcomes within older patient groups with respect to pathologic type or surgical approach. Most existing literature on skull base surgery describes younger adult patients, mostly malignant disease, or a smaller cohort of older patients.9-11

To our knowledge, this study is the largest analysis of skull base surgery in a cohort of patients 70 years or older in the current literature. The descriptive data for this cohort provide invaluable insight into the variety of skull base pathologic conditions and frequency of specific intraoperative and postoperative outcomes in this population. This study demonstrates no clinically significant difference in noteworthy intraoperative or postoperative outcomes and complications based on increasing age, surgical approach (endoscopic vs open), or presence of malignant neoplasm in the older patient population at our institution. Although previous studies have found higher rates of perioperative complications and mortality in patients 70 years or older undergoing skull base surgery, a subanalysis of outcomes based on malignancy status, increasing older age, or operative approach has not been performed in this population.9-11 The results of our analysis suggest that skull base surgery, including the standard-of-care endoscopic endonasal approach, is a safe and feasible option for resection of skull base disease in the patients 70 years or older, regardless of age or malignancy status. Complication rates were overall low and similar to, if not lower than, those reported in all adults in the existing literature.7

Limitations

Several limitations in our analysis must be discussed. The frequency of certain intraoperative and postoperative outcomes was generally low in our patient population. This finding reflects our institution’s experience with and volume of skull base surgery and the team-based multidisciplinary approach we use for all patients undergoing skull base surgery. These results may not be generalizable to new programs and their learning curves or to institutions without comprehensive skull base centers.

Appropriate caution must be taken when analyzing and interpreting retrospective data; however, there is likely not a superior, ethical alternative to a retrospective outcomes analysis for skull base surgery. In addition, selection bias regarding endoscopic and open surgery patient cohorts cannot be understated when comparing these 2 groups. In our cohort, the most endoscopic procedures were for resection of benign disease, and most of the open procedures were for resection of malignant disease. In some cases, patients who undergo endoscopic surgery may also have less extensive disease than patients for whom an open approach is required. However, as previously discussed, no statistical difference in outcomes was noted between approaches or malignancy status, and both of these variables were included in our multivariate regression model. Complication rates were overall low regardless of approach and pathologic process in our cohort of patients 70 years or older.

The selection bias potentially present in patients selected for surgical management of skull base disease must also be addressed. It is likely that a fraction of patients 70 years or older at this institution were not eligible for surgery owing to comorbidities and other factors, and patients selected for surgery by the multidisciplinary skull base team may have superior overall health status, resulting in biased operative outcomes. Additional studies are needed to further analyze and describe any fundamental patient and disease factors that differ between older patients with skull base abnormalities who receive surgical vs nonsurgical treatment. Such analyses will enable superior selection of patients who may benefit more and experience less risk from skull base surgery.

Of note, the approach to care and goals of care in this older cohort did not differ from those used in managing skull base abnormalities among the general patient population of all ages at this institution. In general, gross total resection is the goal for all patients, and perceived ability to achieve total resection is a strong consideration in choosing surgical management; however, in select, cases small fragments of benign lesion may be intentionally left behind if surgical goals, such as decompression or symptom management, have been achieved.

In addition, the power of this study is limited by the small number of outcome events in our 219-patient cohort. As skull base surgery becomes increasingly more common in patients 70 years or older, the size and statistical power of this cohort will increase. Future analysis of our growing older skull base surgical population will provide a clinically relevant complement to this study. In addition, future studies of a larger cohort should include a cost analysis of skull base surgery in patients 70 years or older compared with younger adults, which will provide further insight into any potential differences in health system–related costs associated with skull base surgery in older patients.

Conclusions

Among older patients selected for surgery at our institution, skull base surgery is a safe option, with similar outcomes across ages 70 years or older, surgical approaches, and skull base abnormalities. This analysis provides novel data to support appropriate use of the endoscopic endonasal approach for resection of skull base disease in patients 70 years or older without evidence of worse intraoperative or postoperative outcomes compared with the traditional open approach in this population.

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Article Information

Accepted for Publication: June 25, 2018.

Corresponding Author: Elizabeth D. Stephenson, BA, Department of Otolaryngology–Head and Neck Surgery, University of North Carolina Memorial Hospitals, 170 Manning Dr, Physician’s Office Building, Ground Floor, Campus Box 7070, University of North Carolina, Chapel Hill, NC 27599-7070 (elizabeth_stephenson@med.unc.edu).

Published Online: September 20, 2018. doi:10.1001/jamaoto.2018.1948

Author Contributions: Ms Stephenson and Dr Zanation had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Stephenson, Sasaki-Adams, Farquhar, Ebert, Ewend, Thorp.

Acquisition, analysis, or interpretation of data: Stephenson, Lee, Sasaki-Adams, Farquhar, Farzal, Sasaki-Adams, Thorp, Zanation.

Drafting of the manuscript: Stephenson, Adams, Ebert.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Stephenson, Sasaki-Adams, Farquhar, Farzal.

Administrative, technical, or material support: Stephenson, Sasaki-Adams, Ewend, Zanation.

Supervision: Stephenson, Farzal, Ebert, Ewend, Sasaki-Adams, Thorp, Zanation.

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Zanation reported serving as a paid consultant for Medtronic, Stryker, and Johnson & Johnson. Dr Ewend reported being a board member of and owning stock in Falcon Therapeutics, a small start-up company interested in using neurologic stem cells to treat brain tumors; he receives no royalties or funds. No other disclosures were reported.

Funding/Support: Dr Farzal acknowledges support from National Institutes of Health National Research Service Award Institutional Training Grant 5T32DC005360 to the University of North Carolina at the time this research was conducted. This grant supports the T32 seven-year–track research residents in Otolaryngology–Head and Neck Surgery at the University of North Carolina and helps fund their research. No grant funds were used for this study. All material support for this research was provided by the Department of Otolaryngology–Head and Neck Surgery at the University of North Carolina at Chapel Hill.

Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Meeting Presentation: This article was presented at the Triological Society Section Meeting; January 19, 2018; Scottsdale, Arizona.

References
1.
Dutta  R, Dubal  PM, Svider  PF, Liu  JK, Baredes  S, Eloy  JA.  Sinonasal malignancies: a population-based analysis of site-specific incidence and survival.  Laryngoscope. 2015;125(11):2491-2497. doi:10.1002/lary.25465PubMedGoogle ScholarCrossref
2.
Roxbury  CR, Ishii  M, Richmon  JD, Blitz  AM, Reh  DD, Gallia  GL.  Endonasal endoscopic surgery in the management of sinonasal and anterior skull base malignancies.  Head Neck Pathol. 2016;10(1):13-22. doi:10.1007/s12105-016-0687-8PubMedGoogle ScholarCrossref
3.
Snyderman  CH, Carrau  RL, Kassam  AB,  et al.  Endoscopic skull base surgery: principles of endonasal oncological surgery.  J Surg Oncol. 2008;97(8):658-664. doi:10.1002/jso.21020PubMedGoogle ScholarCrossref
4.
Rawal  RB, Farzal  Z, Federspiel  JJ, Sreenath  SB, Thorp  BD, Zanation  AM.  Endoscopic resection of sinonasal malignancy: a systematic review and meta-analysis.  Otolaryngol Head Neck Surg. 2016;155(3):376-386. doi:10.1177/0194599816646968PubMedGoogle ScholarCrossref
5.
Farquhar  D, Kim  L, Worrall  D,  et al.  Propensity score analysis of endoscopic and open approaches to malignant paranasal and anterior skull base tumor outcomes.  Laryngoscope. 2016;126(8):1724-1729. doi:10.1002/lary.25885PubMedGoogle ScholarCrossref
6.
Buchmann  L, Larsen  C, Pollack  A, Tawfik  O, Sykes  K, Hoover  LA.  Endoscopic techniques in resection of anterior skull base/paranasal sinus malignancies.  Laryngoscope. 2006;116(10):1749-1754. doi:10.1097/01.mlg.0000233528.99562.c2PubMedGoogle ScholarCrossref
7.
Ganly  I, Patel  SG, Singh  B,  et al.  Complications of craniofacial resection for malignant tumors of the skull base: report of an international collaborative study.  Head Neck. 2005;27(6):445-451. doi:10.1002/hed.20166PubMedGoogle ScholarCrossref
8.
Deiner  S, Westlake  B, Dutton  RP.  Patterns of surgical care and complications in elderly adults.  J Am Geriatr Soc. 2014;62(5):829-835. doi:10.1111/jgs.12794PubMedGoogle ScholarCrossref
9.
Ganly  I, Patel  SG, Singh  B,  et al.  Craniofacial resection for malignant tumors involving the skull base in the elderly: an international collaborative study.  Cancer. 2011;117(3):563-571. doi:10.1002/cncr.25390PubMedGoogle ScholarCrossref
10.
Ganly  I, Gross  ND, Patel  SG, Bilsky  MH, Shah  JP, Kraus  DH.  Outcome of craniofacial resection in patients 70 years of age and older.  Head Neck. 2007;29(2):89-94. doi:10.1002/hed.20487PubMedGoogle ScholarCrossref
11.
Hentschel  SJ, Nader  R, Suki  D, Dastgir  A, Callender  DL, DeMonte  F.  Craniofacial resections in the elderly: an outcome study.  J Neurosurg. 2004;101(6):935-943. doi:10.3171/jns.2004.101.6.0935PubMedGoogle ScholarCrossref
12.
Harris  PA, Taylor  R, Thielke  R, Payne  J, Gonzalez  N, Conde  JG.  Research electronic data capture (REDCap)—a metadata-driven methodology and workflow process for providing translational research informatics support.  J Biomed Inform. 2009;42(2):377-381. doi:10.1016/j.jbi.2008.08.010PubMedGoogle ScholarCrossref
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