Abstract
Introduction
With an aging population, the proportion of patients aged ≥80 years requiring cervical surgery is increasing. Surgeons are concerned with the high incidence of complications in this population, because “age” itself has been reported as a strong risk factor for complications. However, it is still unknown which factors represent higher risk among these elderly patients. Therefore, this study was conducted to identify the risk factors related to surgical complications specific to elderly patients by analyzing the registry data of patients aged ≥80 years who underwent cervical surgery.
Methods
We retrospectively studied multicenter collected registry data using multivariate analysis. Sixty-six patients aged ≥80 years who underwent cervical surgery and were followed up for more than one year were included in this study. Preoperative patient demographic data, including comorbidities and postoperative complications, were collected from multicenter registry data. Complications were considered as major if they required invasive intervention, caused prolonged morbidity, or resulted in prolongation of hospital stay. Logistic regression analysis was performed to analyze the risk factors for complications. A p-value of <0.05 was considered as statistically significant.
Results
The total number of patients with complications was 21 (31.8%), with seven major (10.6%) and 14 minor (21.2%) complications. Multivariate logistic regression analysis, after adjusting for age, revealed two significant risk factors: preoperative cerebrovascular disorders (OR, 6.337; p=0.043) for overall complications and cancer history (OR, 8.168; p=0.021) for major complications. Age, presence of diabetes mellitus, and diagnosis were not significant predictive factors for complications in this study.
Conclusions
Preoperative cerebrovascular disorders and cancer history were risk factors for complications after cervical surgery in patients over 80 years old. Surgeons should pay attention to these specific risk factors before performing cervical surgery in elderly patients.
Keywords: elderly, complications, cervical surgery, risk factor, cancer history, cerebrovascular disorders, comorbidity
Introduction
According to World Health Organization reports1), the mean life expectancy in 28 countries, such as Japan, Switzerland, Singapore, Australia, and Spain, etc., were over 80 years in 2015. Additionally, “healthy life expectancy”, which indicates the average number of years that a person can expect to live in full health, is getting longer. As the population ages, the number of patients with degenerative spinal diseases, such as cervical spondylotic myelopathy (CSM), is increasing. Some may need surgery at around 80 years old in severe cases2-4) owing to recent advances in surgical techniques and general anesthesia. Furthermore, clinical results of surgery for the aged population were reported to not be inferior compared to that in young patients5,6). Therefore, surgeons must prepare for the expected future increase in aged patients who will need cervical spine surgery.
What concerns surgeons when performing cervical surgery on an elderly patient is the increased incidence of complications, because “age” itself is considered a strong risk factor for complications7-9). It is widely accepted that once complications occur, the health-related quality of life (HRQOL) will remarkably decrease and large additional costs will be needed10,11). Other factors were reported to relate to complications, such as diabetes mellitus (DM)12), operative time9), surgical procedure9), and the number of comorbidities8). However, the subjects studied in these reports were of various ages, and the risk factors specific to the elderly patients are still unknown. Based on this background, this study was conducted to identify the risk factors specific to the elderly through analyzing the data of patients aged ≥80 years who underwent cervical surgery.
Materials and Methods
Study Design
This study retrospectively analyzed registry data of patients aged ≥80 years at 35 facilities belonging to the Japan Association of Spine Surgeons with Ambition in 2015.
Patient Population
We conducted our survey from January to March of 2015. The inclusion criteria were patients who were aged ≥80 years when they underwent spinal surgery, who have been followed up more than one year postoperatively, who agreed to participate in our study, and who answered the questionnaires about surgical outcomes. The patients who underwent surgery for cancer-related spinal stenosis or instability, as well as those in which perioperative information could not be completely determined, were excluded. Thus, 262 patients were registered for this multicenter survey. Fifteen patients with thoracic spine disease, 179 with lumbar spine disease, two with traumatic cervical injury and cervical spine benign tumors were excluded. Finally, 66 patients diagnosed with degenerative cervical myelopathy, who underwent cervical surgery, were enrolled in this study (Fig. 1). The data of preoperative comorbidities were collected from medical records and were divided into “cancer history”, “cardiac disorders”, “cerebrovascular disorders”, “respiratory disorders”, “renal disorders”, “gastro-intentional disorders”, “DM”, “hypertension”, and “dementia”.
Figure 1.
Inclusion and exclusion criteria.
Definitions of complications
All reported adverse events were reviewed, and each adverse event was judged as to whether it constituted a potential complication related to the surgical procedure by a panel of two physicians (HT and KT). Complications were further classified as minor or major. The major complications were defined as if they required invasive intervention, resulted in permanent or prolonged morbidity, or resulted in substantial prolongation of hospital stay9,13). Based on this definition, epidural hemorrhage, cerebral infarction, systemic edema, arrhythmia, acute respiratory disorders, and epileptic seizures were classified as major complications; delirium, C5 nerve root palsy, urinary tract infection, temporal neurological deterioration, and dural tear were classified as minor complications.
Statistical Analysis
Data were analyzed using Statistical Package for Social Sciences (SPSS) software, version 23.0 (IBM Inc, Chicago, IL, USA). Univariate analyses were performed to identify correlations between complications and prognostic factors. The chi-square test was used to assess categorical variables. A proportional odds model was used to compute odds ratios (OR) and 95% confidence intervals (95% CI). The following variables were examined: age, gender, disease duration, smoking status, diagnosis (CSM, ossification of the posterior cervical longitudinal ligament [OPLL] and atlantoaxial dislocation [AAD]), drug use (anti-osteoporosis agents and anticoagulants), cancer history, and comorbidities (cardiac disorders, cerebrovascular disorders, respiratory disorders, renal disorders, gastrointestinal disorders, DM, hypertension and dementia). Continuous variables were categorized as follows: age, less than 85 years or more; and disease duration, less than 12 months or longer. Variables with a p value <0.05, as per univariate analysis, were included in the multivariate logistic regression model, which was adjusted to age (less than 85 years or more). A p-value <0.05 was considered as statistically significant for multivariate logistic regression.
Results
Patient demographics are shown in Table 1; average age was 83.4 years (range: 80-91 years). Males comprised 31 cases and females 35. Average disease duration was 24.1 months (range: 12-96). Diagnoses were CSM in 57 cases, OPLL in six cases, AAD in two cases, and cervical disc herniation in one case.
Table 1.
Patient’s Demographics.
| Number | ||
|---|---|---|
| Total number | 66 | |
| Age (yr) | 83.4 (80-91) | |
| Gender (male/ female) | 31/35 | |
| Disease duration (month) | 24.1 (1-240) | |
| Smoking status (n, %) | 1 (1.5%) | |
| Drug use (n, %) | ||
| Anticoagulants | 18 (27.3%) | |
| Osteoporosis medication | 12 (18.2%) | |
| History of cancer | 12 (18.2%) | |
| Comorbidity (n, %) | ||
| Hypertension | 28 (42.4%) | |
| Cardiac disorders | 15 (22.7%) | |
| Diabetes | 10 (15.2%) | |
| Gastrointestinal disorders | 9 (13.6%) | |
| Cerebrovascular disorders | 7 (10.6%) | |
| Renal disorders | 6 (9.1%) | |
| Respiratory disorders | 4 (6.1%) | |
| Dementia | 2 (3.0%) | |
| Diagnosis (n, %) | ||
| CSM | 57 (86.4%) | |
| OPLL | 6 (9.1%) | |
| AAD | 2 (2.0%) | |
| CDH | 1 (1.5%) | |
| Surgical method | ||
| Posterior | 64 (97.0%) | |
| Anterior | 2 (3.0%) | |
| Decompression only | 53 (80.3%) | |
| Decompression with fusion | 13 (19.7%) | |
| Mean surgical segments | ||
| Decompression | 3.8 (1-7) | |
| Fusion | 2.5 (1-8) | |
| Estimated blood loss (ml) | 166.2 (5-1160) | |
| Surgical time (min) | 152.2 (46-418) | |
CSM: Cervical spondylotic myelopathy, OPLL: Ossification of posterior longitudinal ligament of the cervical spine, AAD: atlanto-axial dislocation, CDH: Cervical disc herniation, yr: years old, n: number
The number of complications
Overall complication rate was 31.8% (21 cases). Major complications comprised 10.6% (7 cases) and minor 21.4% (14 cases). The details of each complication are listed in Table 2. Delirium occurred in 9.1% (six cases), C5 nerve root palsy and urinary tract infection in 4.5% (three cases) and temporal neurological deterioration and dural tear in 3.0% (one case). As for the major complications, 3.0% (two cases) developed epidural hemorrhage, and 1.5% (one case) developed cerebral infarction, systemic edema, arrhythmia, acute respiratory disorder, and epileptic seizure. In our data set, each complication occurred in a patient; i.e., no patient experienced more than one complication.
Table 2.
Details of Complications.
| Number (%) | ||
|---|---|---|
| Overall complication | 21 (31.8) | |
| Major complication | 7 (10.6) | |
| Epidural hemorrhage | 2 (3.0) | |
| Cerebral infarction | 1 (1.5) | |
| Systemic edema | 1 (1.5) | |
| Arrhythmia | 1 (1.5) | |
| Acute respiratory disorder | 1 (1.5) | |
| Epileptic seizure | 1 (1.5) | |
| Minor complication | 14 (21.2) | |
| Delirium | 6 (9.1) | |
| C5 nerve root palsy | 3 (4.5) | |
| Urinary tract infection | 3 (4.5) | |
| Temporal neurological deterioration | 1 (1.5) | |
| Dural tear | 1 (1.5) | |
Univariate and multivariate analysis
Univariate logistic regression analysis showed that cerebral disorders (OR, 5.694; p=0.045) and renal disorders (OR, 1.211; p=0.012) were significant risk factors for overall complications; cancer history (OR, 8.500; p=0.017) was a significant risk factor for major complications. The presence of DM, age, diagnosis, and surgical method were not predictive factors for complications in this study. Multivariate logistic regression analysis revealed two significant risk factors: cerebrovascular disorders (OR, 6.337; p=0.043) for overall complications and cancer history (OR, 8.168; p=0.021) for major complications (Table 3, 4).
Table 3.
Risk Factors of Overall Complications.
| Risk factor | (Reference) | Univariate | Multivariate | |||||
|---|---|---|---|---|---|---|---|---|
| OR | 95%CI | p value | OR | 95%CI | p value | |||
| Age ≥85 yr | (<85yo) | 0.996 | 0.344-2.882 | 0.606 | ||||
| Gender male | (female) | 0.726 | 0.263-2.004 | 0.359 | ||||
| Disease duration ≥12mo | (<12mo) | 1.661 | 0.570-4.842 | 0.254 | ||||
| Smoking status | (w/o) | 0.977 | 0.933-1.023 | 0.652 | ||||
| Drug use | ||||||||
| Anticoagulants | (w/o) | 1.273 | 0.415-3.907 | 0.442 | ||||
| Osteoporosis medication | (w/o) | 0.921 | 0.245-3.461 | 0.592 | ||||
| History of cancer | (w/o) | 2.176 | 0.612-7.742 | 0.188 | ||||
| Comorbidity | ||||||||
| Hypertension | (w/o) | 0.540 | 0.177-1.644 | 0.207 | ||||
| Cardiac | (w/o) | 1.914 | 0.592-6.193 | 0.215 | ||||
| Diabetes | (w/o) | 0.314 | 0.063-1.1578 | 0.129 | ||||
| Gastrointestinal | (w/o) | 0.925 | 0.209-4.100 | 0.617 | ||||
| Cerebrovascular | (w/o) | 5.694 | 1.009-32.150 | 0.045 | 6.337 | 1.056-38.525 | 0.043 | |
| Renal | (w/o) | 1.211 | 1.004-1.460 | 0.012 | 2.395 | 0.731-16.441 | 0.106 | |
| Respiratory | (w/o) | 6.300 | 0.616-64.426 | 0.118 | ||||
| Dementia | (w/o) | 1.909 | 0.144-32.009 | 0.579 | ||||
| Diagnosis | ||||||||
| OPLL | (CSM) | 5.125 | 0.853-30.788 | 0.075 | ||||
| AAD | (CSM) | 0.281 | 0.185-0.425 | 0.089 | ||||
| Surgical method | ||||||||
| Posterior | (Anterior) | 0.524 | 0.031-8.783 | 0.579 | ||||
| With Fusion | (w/o) | 2.682 | 0.718-10.015 | 0.171 | ||||
CSM: Cervical spondylotic myelopathy, OPLL: Ossification of posterior longitudinal ligament of the cervical spine, AAD: atlanto-axial dislocation, CDH: Cervical disc herniation, dis: disorder, yr: years old, mo: month, w/o: without
Table 4.
Risk Factors of Major Complications.
| Risk factor | (Reference) | Univariate | Multivariate | |||||
|---|---|---|---|---|---|---|---|---|
| OR | 95%CI | p value | OR | 95%CI | p value | |||
| Age ≥85 yr | (>85) | 1.436 | 0.298-7.179 | 0.466 | ||||
| Gender male | (female) | 0.315 | 0.057-1.757 | 0.166 | ||||
| Disease duration ≥12mo | (12mo) | 3.294 | 0.665-16.307 | 0.138 | ||||
| Smoking status | (w/o) | 0.983 | 0.951-1.017 | 0.894 | ||||
| Drug use | ||||||||
| Anticoagulants | (w/o) | 1.075 | 0.189-6.109 | 0.622 | ||||
| Osteoporosis agents | (w/o) | 0.797 | 0.700-0.906 | 0.277 | ||||
| History of cancer | (w/o) | 8.500 | 1.597-45.254 | 0.017 | 8.168 | 1.377-48.454 | 0.021 | |
| Comorbidity | ||||||||
| Hypertension | (w/o) | 0.724 | 0.129-4.059 | 0.534 | ||||
| Cardiac | (w/o) | 1.415 | 0.246-8.158 | 0.504 | ||||
| Diabetes | (w/o) | 0.797 | 0.700-0.906 | 0.227 | ||||
| Gastrointestinal | (w/o) | 1.063 | 0.113-10.024 | 0.661 | ||||
| Cerebrovascular | (w/o) | 4.320 | 0.660-28.266 | 0.157 | ||||
| Renal | (w/o) | 5.500 | 0.799-37.837 | 0.118 | ||||
| Respiratory | (w/o) | 0.932 | 0.870-0.999 | 0.631 | ||||
| Dementia | (w/o) | 0.966 | 0.921-1.013 | 0.798 | ||||
| Diagnosis | ||||||||
| OPLL | (CSM) | 0.895 | 0.819-1.978 | 0.534 | ||||
| AAD | (CSM) | 8.500 | 0.469-154.174 | 0.225 | ||||
| Surgical method | ||||||||
| Posterior | (Anterior) | 1.123 | 0.879-1.433 | 0.798 | ||||
| With Fusion | (w/o) | 4.784 | 0.898-25.456 | 0.084 | ||||
CSM: Cervical spondylotic myelopathy, OPLL: Ossification of posterior longitudinal ligament of the cervical spine, AAD: atlanto-axial dislocation, CDH: Cervical disc herniation, DM: diabetes mellitus, yr: years old, mo: month, w/o: without
Discussion
This study verified novel candidates as risk factors for complications that were not reported before: cerebrovascular disorders and cancer history. Boaky et al.8) reported that age (ref=18-44, 65-84 years: OR=2.28, ≥85 years: OR=5.07) and number of comorbidities (ref=less than two, ≥ three: OR=1.98) were risk factors for complications of cervical surgery. Furthermore, Fehlings et al.9) reported that risk factors for cervical surgery were age (OR=1.029) and operative duration (OR=1.005) for overall complications, and age (OR=1.054) and combined anterior-posterior procedures (OR=5.297) for major complications. Although these were well-designed retrospective or prospective studies with adequate sample size, the average age in these reports was 55 and 57 years, respectively. However, we focused in our survey on elderly patients with an average age of 83.4 years to enable us to identify the novel factors.
In our study, 18.2% of patients were cancer survivors and 10.6% had cerebrovascular disorders as a comorbidity, which were much higher than previous studies14). On the other hand, the number of patients with DM was similar12) and that of smokers was extremely low14). These characteristics could reflect two types of selection. First is the surgeon's selection; surgeons tend to avoid performing operations for patients with risk factors, such as DM or smoking, especially in elderly patients. Second is the natural selection; patients with risk factors tend to have shorter life expectancy.
Our study did not include patients who underwent surgery for cancer-related myelopathy or instability; therefore, cancer itself had little impact on the outcomes. Nevertheless, cancer history may be a candidate risk factor. This may relate to the potential damage secondary to cancer therapy. For example, many types of chemotherapy were reported to have chronic cardiotoxic effects15). It is reported that the incidence of congestive heart failure (CHF) was 29.4% in patients who received trastuzumab, which is a major chemotherapy for breast cancer16). Moreover, anthracyclines17), fluoropyrimidines18), tyrosine kinase inhibitors19), and bevacizumab20), which are known vascular endothelial growth factor (VEGF) inhibitors, were also associated with CHF. Additionally, radiotherapy may lead to fibrosis in lung, liver, vascular, or other major organs21). These potential systemic after-effects, which cannot be detected by the general preoperative examinations, such as blood test, radiography, electrocardiography or echocardiography, may be related to our result that cancer history is a risk factor for major complications, even with no cancer recurrence. Regarding history of cerebrovascular disorders as a risk factor for overall complications, it is well reported that cerebrovascular disease is significantly associated with the incidence of delirium22,23). These may relate to our results because postoperative delirium was the most popular complication in our cohort.
In contrast, our results dismissed some well-known risk factors for postoperative complications. Cook et al suggested that DM is a risk factor for cardiac complications (OR=1.57), hematomas (OR=5.13), and postoperative infection (OR=7.46)12). Hasegawa et al.24) reported that OPLL (OR=19.0) is also related to complications. However, these two factors were not significantly related to complications in our study. Although these may be due to the surgeon's selection to consider the surgical indication, novel surgical indication for such elderly patients would be an area for debate, including characteristics for aged populations, such as cancer history, muscle volume25), dementia, and vascular age.
Although our results can provide beneficial information for surgeons and patients, this study had some limitations. First, the sample size was small. However, the rate of cervical surgery for patients over 80 years is relatively low compared to overall surgery26) and we only reviewed fully recorded preoperative comorbidities and postoperative complications with a follow-up of more than one year from 35 facilities. Our inclusion criteria were strict enough to keep the results reliable. Second is the retrospective design based on data review, which did not allow evaluation of the severity of the comorbidities and complications. Finally, cancers have different types and staging systems, and cancer therapy has many classes. Although sub-analyses considering these variations are needed, the current study did not allow for them. Therefore, large-scale, prospective studies with more details on comorbidities and complications are critical to overcome these limitations.
In conclusion, preoperative cerebrovascular disorders and cancer history were risk factors for overall complications and major complication after cervical surgery, especially in patients aged over 80 years. Because there is a trend of population aging and prolongation of the healthy life expectancy, the chance of the elderly undergoing cervical surgery is expected to increase. Surgeons should pay attention to these specific factors in elderly patients to improve the safety of cervical operations.
Conflicts of Interest: The authors declare that there are no conflicts of interest.
References
- 1.World Health Organization. World health statistics. Geneva, Switzerland: World Health Organization, 2016:7-11. [Google Scholar]
- 2.Machino M, Yukawa Y, Hida T, et al. The prevalence of pre- and postoperative symptoms in patients with cervical spondylotic myelopathy treated by cervical laminoplasty. Spine (Phila Pa 1976) 2012;37(22):E1383-8. [DOI] [PubMed] [Google Scholar]
- 3.Fehlings MG, Ibrahim A, Tetreault L, et al. A global perspective on the outcomes of surgical decompression in patients with cervical spondylotic myelopathy: results from the prospective multicenter AOSpine international study on 479 patients. Spine (Phila Pa 1976) 2015;40(17):1322-8. [DOI] [PubMed] [Google Scholar]
- 4.Suzuki A, Misawa H, Simogata M, et al. Recovery process following cervical laminoplasty in patients with cervical compression myelopathy: prospective cohort study. Spine (Phila Pa 1976) 2009;34:2874-9. [DOI] [PubMed] [Google Scholar]
- 5.Nagashima H, Dokai T, Hashiguchi H, et al. Clinical features and surgical outcomes of cervical spondylotic myelopathy in patients aged 80 years or older: a multi-center retrospective study. Eur Spine J 2011;20(2):240-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Machino M, Yukawa Y, Imagama S, et al. Surgical Treatment Assessment of Cervical Laminoplasty Using Quantitative Performance Evaluation in Elderly Patients: A Prospective Comparative Study in 505 Patients With Cervical Spondylotic Myelopathy. Spine (Phila Pa 1976) 2016;41(9):757-63. [DOI] [PubMed] [Google Scholar]
- 7.Furlan JC, Kalsi-Ryan S, Kailaya-Vasan A, et al. Functional and clinical outcomes following surgical treatment in patients with cervical spondylotic myelopathy: a prospective study of 81 cases. J Neurosurg Spine 2011;14(3):348-55. [DOI] [PubMed] [Google Scholar]
- 8.Boakye M, Patil CG, Santarelli J, et al. Cervical spondylotic myelopathy: complications and outcomes after spinal fusion. Neurosurgery 2008;62(2):455-61; discussion 61-2. [DOI] [PubMed] [Google Scholar]
- 9.Fehlings MG, Smith JS, Kopjar B, et al. Perioperative and delayed complications associated with the surgical treatment of cervical spondylotic myelopathy based on 302 patients from the AOSpine North America Cervical Spondylotic Myelopathy Study. J Neurosurg Spine 2012;16(5):425-32. [DOI] [PubMed] [Google Scholar]
- 10.Daniels AH, Kawaguchi S, Contag AG, et al. Hospital charges associated with “never events”: comparison of anterior cervical discectomy and fusion, posterior lumbar interbody fusion, and lumbar laminectomy to total joint arthroplasty. J Neurosurg Spine 2016;25(2):165-9. [DOI] [PubMed] [Google Scholar]
- 11.Miller JA, Lubelski D, Alvin MD, et al. C5 palsy after posterior cervical decompression and fusion: cost and quality-of-life implications. Spine J 2014;14(12):2854-60. [DOI] [PubMed] [Google Scholar]
- 12.Cook C, Tackett S, Shah A, et al. Diabetes and perioperative outcomes following cervical fusion in patients with myelopathy. Spine (Phila Pa 1976) 2008;33(8):E254-60. [DOI] [PubMed] [Google Scholar]
- 13.Glassman SD, Alegre G, Carreon L, et al. Perioperative complications of lumbar instrumentation and fusion in patients with diabetes mellitus. Spine J 2003;3(6):496-501. [DOI] [PubMed] [Google Scholar]
- 14.Buerba RA, Giles E, Webb ML, et al. Increased risk of complications after anterior cervical discectomy and fusion in the elderly: an analysis of 6253 patients in the American College of Surgeons National Surgical Quality Improvement Program database. Spine (Phila Pa 1976) 2014;39(25):2062-9. [DOI] [PubMed] [Google Scholar]
- 15.Accordino MK, Neugut AI, Hershman DL. Cardiac effects of anticancer therapy in the elderly. J Clin Oncol 2014;32:2654-61. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Chavez-MacGregor M, Zhang N, Buchholz TA, et al. Trastuzumab-related cardiotoxicity among older patients with breast cancer. J Clin Oncol 2013;31(33):4222-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Yeh ET, Bickford CL. Cardiovascular complications of cancer therapy: incidence, pathogenesis, diagnosis, and management. J Am Coll Cardiol 2009;53(24):2231-47. [DOI] [PubMed] [Google Scholar]
- 18.Jensen SA, Sorensen JB. Risk factors and prevention of cardiotoxicity induced by 5-fluorouracil or capecitabine. Cancer Chemother Pharmacol 2006;58(4):487-93. [DOI] [PubMed] [Google Scholar]
- 19.Escudier B, Eisen T, Stadler WM, et al. Sorafenib in advanced clear-cell renal-cell carcinoma. N Engl J Med 2007;356(2):125-34. [DOI] [PubMed] [Google Scholar]
- 20.Miller K, Wang M, Gralow J, et al. Paclitaxel plus bevacizumab versus paclitaxel alone for metastatic breast cancer. N Engl J Med 2007;357(26):2666-76. [DOI] [PubMed] [Google Scholar]
- 21.Cuzick J, Stewart H, Rutqvist L, et al. Cause-specific mortality in long-term survivors of breast cancer who participated in trials of radiotherapy. J Clin Oncol 1994;12(3):447-53. [DOI] [PubMed] [Google Scholar]
- 22.Gosselt AN, Slooter AJ, Boere PR, et al. Risk factors for delirium after on-pump cardiac surgery: a systematic review. Crit Care 2015;19:346. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Gleason LJ, Schmitt EM, Kosar CM, et al. Effect of Delirium and Other Major Complications on Outcomes After Elective Surgery in Older Adults. JAMA Surg 2015;150(12):1134-40. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Hasegawa K, Homma T, Chiba Y. Upper extremity palsy following cervical decompression surgery results from a transient spinal cord lesion. Spine (Phila Pa 1976) 2007;32(6):E197-202. [DOI] [PubMed] [Google Scholar]
- 25.Rosenberg IH. Sarcopenia: origins and clinical relevance. J Nutr 1997;127(5 Suppl):990S-1S. [DOI] [PubMed] [Google Scholar]
- 26.Maeno T, Okuda S, Yamashita T, et al. Age-related surgical outcomes of laminoplasty for cervical spondylotic myelopathy. Global Spine J 2015;5(2):118-23. [DOI] [PMC free article] [PubMed] [Google Scholar]