Perioperative complications in patients aged ≥85 years undergoing spinal surgery: a retrospective comparative study of pre-old and old patients in Japan

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Asian Spine J. 2024;18(6):856-866

Publication date (electronic) : 2024 October 22

doi : https://doi.org/10.31616/asj.2024.0215

Takahiro Mui, Hideki Shigematsu, Masaki Ikejiri, Sachiko Kawasaki, Yasuhito Tanaka

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Japan

Corresponding author: Hideki Shigematsu, Department of Orthopaedic Surgery, Nara Medical University, 840, Shijo-cho, Kashihara-shi, Nara, 634-8522, Japan, Tel: +81-744-22-3051, Fax: +81-744-22-4121, E-mail: shideki@naramed-u.ac.jp

Received 2024 June 4; Revised 2024 August 21; Accepted 2024 September 1.

Abstract

Introduction

Japan is facing a significant demographic shift owing to its rapidly aging population. In 2007, 27.4 million people (22% of the total population) were ≥65 years old, of whom 7.13 million people were ≥80 years old [1]. In 2014, 9.64 million people were ≥80 years old [2]. Spinal degenerative diseases, such as lumbar spinal stenosis, cervical spondylotic myelopathy, and osteoporotic vertebral fractures, occur more frequently in older populations [3]. The combination of this aging society and recent advances in surgical techniques and anesthesia has increased the demand for spinal surgery in older patients and the number of surgeries performed to achieve a better quality of life [4]. Aizawa et al. [5] reported that the spinal surgery rate in 2010–2014 for individuals aged ≥75 years showed a 7.1-fold increase compared with the rate in 1988–1989. In a Japanese nationwide survey, Imajo et al. [6] showed that age 70–79 years was the most frequent age range at which patients underwent spine surgery in 2011. Globally, Japan has the largest aging population, and older patients requiring spine surgery may be a target intervention group in the future.

Older patients are more likely to have comorbidities, consequently increasing the risk of perioperative complications. Imagama et al. [7] revealed that chronological age and degree of invasiveness were associated with more perioperative adverse events. To date, few studies have reported perioperative complications in extremely older patients (patients aged ≥85 years) [2,8,9]. Therefore, the risk factors for perioperative complications and their effect on the outcomes of patients aged ≥85 years remain unclear. Furthermore, no study has compared younger patients with similar surgeries with those aged ≥85 years.

In this study, we aimed to retrospectively (1) compare the characteristics of perioperative complications in patients aged ≥85 years with those of younger patients with similar conditions undergoing similar spine surgery (studies 1) and (2) investigate factors associated with perioperative complications and clinical outcomes among patients aged ≥85 years (study 2).

Materials and Methods

Study design and patients

The study included patients aged ≥65 years who underwent spinal surgeries between January 2007 and December 2021, excluding cases of implant removal, postoperative hematoma removal, and biopsy. Among these patients, those aged ≥85 years were categorized into the super-old group. Furthermore, patients aged 65–74 and 75–84 years were categorized into the pre-old and old groups, respectively [10].

Clinical data were collected retrospectively from patients’ medical records. the differences in perioperative age-related complications were compared among the super-old, old, and pre-old groups while matching for surgical procedures and general conditions (study 1). Furthermore, preoperative and intraoperative factors for perioperative complications in the super-old group were examined. Patients aged ≥85 years were categorized into two groups based on the presence or absence of complications. Postoperative clinical outcomes were also examined (study 2) (Fig. 1).

Fig. 1

Study design. ASA-PS, American Society of Anesthesiologists Physical Status.

Results

This study included 58, 473, and 591 patients aged ≥85 years (super-old), 75–84 years (old), and 65–74 years (pre-old), respectively. After excluding patients with missing data (ASA-PS), 58 in super-old, 400 in old, and 459 in pre-old patients were analyzed. Patients in the three groups were matched by sex, operative level, disease type, surgical type, and ASA-PS, resulting in 44 patients per group for the analysis of age-related complications. In study 2, data from 58 patients in the super-old group were analyzed to identify risk factors for perioperative complications (Fig. 1).

Comparison of the differences in complications among the super-old, old, and pre-old groups (study 1)

A comparison of the three groups is presented in Table 1. The median patient ages in the three groups were 86, 79, and 70 years, respectively. The total complication rates were 40.9%, 25%, and 18.2% in the super-old, old, and pre-old groups, respectively (p=0.028) (Table 2). Significant differences were observed between the super-old and pre-old groups (p=0.011); in contrast, no significant differences were observed between the other groups (super-old and old groups, p=0.072; old and pre-old groups, p=0.437). Moreover, no significant differences in surgical site complications were observed among the three groups. However, systemic complications showed significant differences among the three groups, becoming more common with increasing age (p=0.013). Significant differences were found between the super-old and pre-old groups (p=0.006); in contrast, no significant differences were found between the other groups (super-old and old groups, p=0.070; old and pre-old groups, p=0.484). Table 2 also shows the details of complications. Two patients aged ≥85 years required reoperation: one for epidural hematoma and the other for screw inside deviation. Major systemic complications occurred in two patients aged ≥85 years (cerebrovascular disease and heart failure) and one patient in the old group (cardiac arrest due to hypoxemia).

Table 1

A comparison of the patients among super-old, old, and pre-old groups

Table 2

Details of perioperative complications for patients in each group (N=44)

Comparison of preoperative and intraoperative factors and clinical course between patients with and without complications in the super-old group (study 2)

Table 3 shows the details of the perioperative complications. The total complication rate was 41.3%, affecting 24 patients. Surgical site and systemic complications occurred in 10 patients (17.2%) and 16 patients (29.3%), respectively. Table 4 shows a comparison between patients with and without surgical site complications among those aged ≥85 years. Surgical site complications were significantly associated with longer surgical duration (p=0.02) and more estimated blood loss (EBL) (p=0.003) (Table 4).

Table 3

Details of perioperative complications in super-old group

Table 4

Relation between surgical site complication and pre- and intraoperative factors

Table 5 shows a comparison between patients with and without systemic complications among those aged ≥85 years. Systemic complications were significantly associated with previous cerebrovascular disease (p=0.014), preoperative motor deficit (p=0.023), and emergency case (p=0.006) and negatively with diabetes mellitus (p=0.048) (Table 5).

Table 5

Relation between systemic complication and pre- and intraoperative factors

Table 6 shows the preoperative and postoperative mobility status. The postoperative mobility status was followed up in 51 of the 58 patients (87.9%). At least one point on the ambulatory status was improved in 37.3%, unchanged in 62.7%, and worsened in 0%. In patients without complications, 41.9% showed an improvement of at least one point postoperatively, whereas in those with complications, 30.0% showed an improvement.

Table 6

Pre- and postoperative moving status

Discussion

In this study, the characteristics of perioperative age-related complications in patients aged ≥85 years were evaluated and compared with those of younger patients undergoing similar spine surgery, In addition, factors associated with perioperative complications and clinical outcomes among patients aged ≥85 years were identified. The study revealed four key findings. First, perioperative complications such as surgical site complications were not significantly different among the super-old, old, and pre-old groups; however, systemic complications increased with advancing age, with significant differences found between the super-old and pre-old groups. Second, in the super-old group, surgical site complications were significantly associated with longer surgical duration and more EBL. Third, systemic complications were significantly associated with previous cerebrovascular disease, preoperative motor deficit, and emergency case and negatively with diabetes mellitus. Finally, the postoperative mobility status of patients aged ≥85 years improved by at least one point in 41.9% and 30.0% of those without and with complications, respectively.

Japan has one of the most rapidly aging populations globally, converting to an increased demand for surgeries among older patients. Spine surgeries improve the quality of life and extend the healthy life expectancy of older individuals [2]. However, to safely perform these procedures, analyzing previous complications and preventing them as early as possible are crucial.

Despite differences in the definitions of surgical complications, level, procedure, and age, previous studies have revealed that complications occur in 12%–66% of patients aged ≥85 years [2,8,9,15]. However, Imajo et al. [6] reported that perioperative complications occurred in 10.4% of all patients undergoing spine surgeries in a 2011 nationwide survey in Japan. In the present study, perioperative age-related complications occurred in 40.9%, 25%, and 18.2% of the super-old, old, and pre-old groups, respectively. Although no significant differences were found in surgical site complications, systemic complications increased with advancing age. These results may present that super-old patients have a reduced reserve capacity for surgical stress, even if their preoperative general condition is comparable with that of younger patients.

Notably, some studies have reported that preoperative motor deficits, emergency operations, comorbidities, surgical duration, EBL, number of spinal levels treated, and fusion with instrumentation are risk factors for perioperative complications [2,4,8,14,15]. In the present study, surgical site complications occurred in 17.2% of patients aged ≥85 years, and surgical duration and greater EBL were identified as risk factors. Factors such as surgical duration and EBL were associated with surgical invasiveness. Surgical invasiveness in spine surgery is a crucial considering with respect to complications, Yoshida et al. [16] showed that a sliding scale, based on preoperative factors, such as age, ASA classification, and the Charlson comorbidity index, could predict acceptable surgical invasiveness in adult spinal deformity surgeries. These predictions decrease the incidence of perioperative complications and improve the outcomes in very old patients.

In this study, systemic complications occurred in 29.3% of the patients, and delirium was the most common systemic complication. Previous studies have also uncovered that postoperative delirium commonly occurs in older patients [17,18]. Onuma et al. [19] revealed that postoperative delirium occurred in 17.7% of patients aged ≥75 years undergoing spinal surgery. Delirium is associated with postoperative mortality, postoperative neurocognitive dysfunction, extended hospitalization, and major postoperative complications and morbidity [20]. A previous study reported that the preoperative risk factors for delirium were a history of stroke, use of nonbenzodiazepine hypnotic drugs, preoperative hyponatremia, and poor nutrition [19]. In the present study, systemic complications, including delirium, were associated with previous cerebrovascular disease, preoperative motor deficit, and emergency case and negatively with diabetes mellitus. According to Deeken et al. [21], a multifaceted, multidisciplinary intervention to prevent delirium reduced the incidence of postoperative delirium and duration in patients aged ≥70 years undergoing elective orthopedic surgery. Therefore, performing surgery at an appropriate time before paralysis worsens symptoms and providing a preoperative multidisciplinary intervention for patients with risk factors for complications are necessary.

In this study, the postoperative mobility status improved in 37.3% of the patients and did not worsen; therefore, improvement can be obtained by performing surgery carefully and appropriately managing patients aged ≥85 years. Furthermore, patient satisfaction is an important treatment goal, along with other objectives. Krauss et al. [22] explored the relationship among patient expectations, satisfaction, and outcomes in cervical spine surgery and found that satisfaction was correlated with pain being the main factor influencing satisfaction. Hikata et al. [23] identified that postoperative lower back or leg pain was a risk factor for poor satisfaction in patients aged ≥80 years after lumbar spine surgery. Despite complication risk, spine surgery for older individuals is a valid option to improve their health-related quality of life. Thus, proposing surgical procedures while focusing on acceptable surgical invasiveness and a patient’s expectations and satisfaction with the procedure is essential. However, insufficient surgery may improve symptoms poorly, leading to diminished improvement in the quality of life and patient satisfaction. Therefore, shared decision-making [24], a collaborative process in which a surgeon and a patient work together to share information about treatment and management options, consider preferred outcomes, and reach an agreement on the best care package for the patient, should be more widely implemented in the future (Fig. 2).

Fig. 2

Conceptual diagram of shared decision-making.

This study has some limitations. First, the sample size was small owing to the single-institutional design, which may have led to the lack of significant differences. In the future, accumulating cases from multiple centers will be necessary. Second, only short-term outcomes were evaluated, and complications such as implant failure or adjacent intervertebral disorders were not assessed. However, in this study, we aimed to clarify perioperative complications in older patients undergoing spinal surgery and consider methods of preventing these complications. Third, selection bias was present. Except for emergency cases and cases of preoperative paralysis, the condition of the patients who opted for surgery was considered relatively well-maintained. However, frailty, which represents a state of increased vulnerability due to age-associated decline in reserve and function leading to reduced ability to cope with every day or acute stressors [25], was not directly assessed. Fourth, this was a retrospective study; thus, some patient information was missing. Particularly, minor complications may not have been recorded, and their incidence may have consequently been rated as “low.” Furthermore, the shared decision-making between patients and surgeons was not evaluated. Therefore, the effect of complications on patients remains unclear. Future prospective studies may eliminate this limitation and reveal the answer to this question. Despite these limitations, the results highlight the characteristics of complications and clinical outcomes after spinal surgery in older patients.

Conclusions

Spine surgery among extremely older patients has relatively high perioperative complication rates. Perioperative complications increased with advancing age, and significant differences were observed in the super-old and pre-old groups.

In surgeries that are expected to be long and involve high EBL, intraoperative and postoperative surgical site complications must be monitored. In addition, patients with previous cerebrovascular disease, preoperative motor deficits, or emergency surgery should be cautious of postoperative systemic complications. The determination of these factors may help prevent perioperative complications.

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