Unplanned Reoperation of Lumbar Spinal Surgery During the Primary Admission: A Multicenter Study Based on a Large Patient Population

Goutallier Grading of Psoas Major and Lumbar Extensor Muscles as a Predictor of Cage Subsidence and Reoperation Following Transforaminal and Posterior Lumbar Interbody Fusion

BACKGROUND CONTEXT

Cage subsidence after transforaminal or posterior lumbar interbody fusion (TLIF/PLIF) is a complication that can lead to recurrence of radiculopathy, loss of correction, and poor patient outcomes. A reliable method to predict subsidence has not yet been established. One recently proposed method involves measuring the degree of fatty degeneration and Goutallier grading of the psoas major (PM) and lumbar extensors (LE) muscle groups, as well as the cross-sectional area (CSA) ratio between these muscle groups and the corresponding vertebrae.

PURPOSE

The purpose of this study was to determine the relationship between (1) Goutallier grading of PM/LE and subsidence, (2) CSA ratio and subsidence, (3) identify the most predictive vertebral level, (4) examine the relationship between these measurements and rates of reoperation, and (5) examine the relationship between these measurements and patient reported outcome measures (PROMs).

STUDY DESIGN/SETTING

This study is a retrospective chart review.

PATIENT SAMPLE

This study included one hundred and sixty-two patients who underwent elective single level TLIF/PLIF from 2007-2022.

OUTCOME MEASURES

Outcome data collected included cage subsidence rates, reoperation rates, Oswestry disability index (ODI), and Patient-Reported Outcomes Measurement Information System (PROMIS) Global scores.

METHODS

A retrospective analysis was performed identifying patients who underwent elective single level TLIF/PLIF from 2007-2022. Muscle parameters collected include the CSA ratio and Goutallier grade of the PM/LE muscle groups at L3/L4, L4/L5, and L5/S1 based on axial CT and MRI. Clinical and radiographic data collected include cage subsidence, osteoporosis diagnosis, reoperation rates, and PROMs.

RESULTS

One hundred sixty-two patients met inclusion criteria. Average follow-up time was 1.6±1.1 years (range:0.13-7.3 years). 81 (50%) patients experienced cage subsidence. Compared to the non-subsidence group, the subsidence group had higher mean Goutallier grade at L3/4 measured in the PM (1.10±1.05 vs. 0.60±0.84, p< 0.001) and LE (1.40±0.89 vs. 1.18±0.76, p=0.047) muscle groups. A Goutallier grade ≥ 2 at L3/4 was associated with an increased risk of subsidence based on PM (OR=4.585, p< 0.001; AUC=0.635; r=0.258, p=0.001) measurements. Increased risk of reoperation was observed in patients with higher Goutallier grades at L3/L4, L4/L5, and L5/S1 based on PM parameters (OR=3.997, p=0.004; OR=3.516, p=0.008; and OR=3.124, p=0.016, respectively), and at L3/4 based on LE parameters (OR 3.462, p=0.009). A significant correlation was found between worse ODI and a higher Goutallier grade at L3-L4 for PM (B= 2.105, p= 0.043). Worse PROMIS Global scores were significantly correlated with higher Goutallier grades at L3-L4 for LE (B= -4.455, p= 0.002). CSA ratios for PM/LE were not strongly correlated with subsidence, PROMs, or reoperation.

CONCLUSION

Our results demonstrated that the degree of fat degeneration of PM and LE is correlated with increased risk of cage subsidence, worse PROMs, and reoperation rates following single level TLIF/PLIF. A Goutallier grade of ≥ 2 of both PM and LE parameters at L3/4 was found to be most predictive of subsidence risk. CSA ratios were not as strongly correlated nor predictive of subsidence. These findings suggest that Goutallier grading of PM and LE show promise as a tool to predict risk of cage subsidence and the need for potential reoperation.

Risk factors for early reoperation in patients after posterior lumbar interbody fusion surgery. A propensity-matched cohort analysis

BACKGROUND

Reoperation is usually associated with poor results and increased morbidity and hospital costs. However, the rates, causes, and risk factors for reoperation in patients undergoing lumbar spinal fusion surgery remain controversial. This study aimed to identify the risk factors for early reoperation after posterior lumbar interbody fusion surgery and to compare the clinical outcomes between patients who underwent reoperation and those who did not.

METHODS

We investigated a multicenter medical record database of 1263 patients who underwent posterior lumbar interbody fusion surgery between 2012 and 2015. A total of 72 (5.7%) reoperations within two years after surgery were identified and were propensity-matched for age, sex, number of fusion segments, and surgeon's experience.

RESULTS

We analyzed a total of 114 patients (57 who underwent reoperation (R group) and 57 who did not (C group)). The mean age was 62.6 ± 13.4 years, with 78 men and 36 women. The mean number of fused segments was 1.2 ± 0.5. Surgical site infection was the most common cause of reoperation. There were significant differences in the incidence of diabetes mellitus (p = 0.024), preoperative ambulation status (p = 0.046), and ASA grade (p < 0.001) between the C and R groups. The recovery rate of the Japanese Orthopaedic Association score was significantly lower in the R group compared to the C group (R: 50.5 ± 28.8%, C: 63.9 ± 33.7%, p = 0.024). There were significant differences in the bone fusion rate (R: 63.2%, C: 96.5%, p < 0.001) and incidence of screw loosening (R: 31.6%; C: 10.5%; p = 0.006).

CONCLUSION

Diabetes mellitus, preoperative ambulation status, and ASA grade were significant risk factors for early reoperation following posterior lumbar interbody fusion surgery. The patients who underwent early reoperation had worse clinical outcomes than those who did not.

Trend of unplanned reoperation rates after lumbar degenerative surgery from 2011 to 2019: a large patient population study

BACKGROUND

Unplanned reoperation is commonly performed due to postoperative complications. Previous studies have reported the incidence of unplanned reoperation following lumbar spinal surgery. But few study focused on the trend of reoperation rates, and the reasons of unplanned reoperation were not clear. In this study, we conducted a retrospective study to determine the trend of unplanned reoperation rates after degenerative lumbar spinal surgery from 2011 to 2019, and the reasons and risk factors of unplanned reoperation were also determined.

METHODS

Data of patients who were diagnosed with degenerative lumbar spinal disease and underwent posterior lumbar spinal fusion surgery in our institution from January 2011 to December 2019 were reviewed. Those who received unplanned reoperation during the primary admission were identified. The demographics, diagnosis, surgical segments and postoperative complications of these patients were recorded. The rates of unplanned reoperation from 2011 to 2019 were calculated, and the reasons of unplanned reoperation were statistically analysed.

RESULTS

A total of 5289 patients were reviewed. Of them, 1.91% (n = 101) received unplanned reoperation during the primary admission. The unplanned reoperation rates of degenerative lumbar spinal surgery firstly increased from 2011 to 2014, with a peak rate in 2014 (2.53%). Then, the rates decreased from 2014 to 2019, with the lowest one in 2019 (1.46%). Patients with lumbar spinal stenosis have a higher rate of unplanned reoperation (2.67%) compared with those diagnosed as lumbar disc herniation (1.50%) and lumbar spondylolisthesis (2.04%) (P < 0.05). The main reasons for unplanned reoperation were wound infection (42.57%), followed by wound hematoma (23.76%). Patients who underwent 2-segment spinal surgery had a higher unplanned reoperation rate (3.79%) than those receiving other segments surgery (P < 0.001). And different spine surgeons had different reoperation rates.

CONCLUSIONS

The rates of unplanned reoperation after lumbar degenerative surgery increased at first and then decreased during past 9 years. Wound infection was the major reason for unplanned reoperation. 2-segment surgery and surgeon's surgical skills were related to the reoperation rate.

Incidences, causes and risk factors of unplanned reoperation within 30 days of craniovertebral junction surgery: a single-center experience

PURPOSE

To investigate the incidences, causes, and risk factors for unplanned reoperation within 30 days of craniovertebral junction (CVJ) surgery.

METHODS

From January 2002 to December 2018, a retrospective analysis of patients who underwent CVJ surgery at our institution was conducted. The demographics, history of the disease, medical diagnosis, approach and type of operation, surgery duration, blood loss, and complications were recorded. Patients were divided into the no-reoperation group and the unplanned reoperations group. Comparison between two groups in noted parameters was analyzed to identify the prevalence and risk factors of unplanned revision and a binary logistic regression was performed to confirm the risk factors.

RESULTS

Of 2149 patients included, 34(1.58%) required unplanned reoperation after the initial surgery. The causes for unplanned reoperation contained wound infection, neurologic deficit, improper screw placement, internal fixation loosens, dysphagia, cerebrospinal fluid leakage, and posterior fossa epidural hematomas. No statistical difference was found in demographics between two groups (P > 0.05). The incidence of reoperation of OCF was significantly higher than that of posterior C1-2 fusion (P = 0.002). In terms of diagnosis, the reoperation rate of CVJ tumor patients was significantly higher than that of malformation patients, degenerative disease patients, trauma patients, and other patients (P = 0.043). The binary logistic regression confirmed that different disease, fusion segment (posterior) and surgery time were independent risk factors.

CONCLUSIONS

The unplanned reoperation rate of CVJ surgery was 1.58% and the major causes were implant-related failures and wound infection. Patients with posterior occipitocervical fusion or diagnosed with CVJ tumors had an increased risk of unplanned reoperation.

Thirty-day unplanned reoperations of thoracic spine surgery: 10 years of data from a single center with 3,242 patients

BACKGROUND CONTEXT

Unplanned reoperation is a useful quality indicator for spine surgery. However, the rates of a 30-day unplanned reoperation in patients undergoing thoracic spinal surgery are not well established.

PURPOSE

To assess the rates, reasons, and risk factors of 30-day unplanned reoperations for thoracic spine surgeries in a single center study.

STUDY DESIGN

A retrospective observational study.

PATIENT SAMPLE

3,242 patients who underwent thoracic spinal surgery at our institution in the past decade were included.

OUTCOME MEASURES

The incidence, chief reasons, and risk factors for unplanned reoperations within 30 days after thoracic spinal surgery.

METHODS

We retrospectively analyzed the data of all patients who underwent thoracic spinal surgery between January 2012 and December 2021. Statistical methods, including univariate and multivariate analyses, were performed to assess the incidence, reasons, and risk factors for thoracic degenerative diseases, spinal tumors, kyphosis deformity, and spinal trauma.

RESULTS

Of the 3,242 patients who underwent thoracic spinal surgery, 107 (3.30%) required unplanned reoperations within 30 days due to epidural hematoma (1.17%), wound complications (0.80%), implant complications (0.43%), inadequate decompression (0.25%), and other causes (0.65%). Patients with degenerative disease (3.88%), spinal tumor (2.98%), and kyphosis deformity (3.33%) had significantly higher incidences of reoperation than those with spinal trauma (1.47%). Unplanned reoperations were classified as hyperacute (30.84%), acute (31.76%), and subacute (37.38%). After univariate analysis, several factors were associated with unplanned reoperation in the 4 cohorts of thoracic spine diseases (p<.05). Multivariate logistic regression analysis revealed that upper thoracic spine surgery (p=.001), concomitant dekyphosis (p=.027), and longer activated partial thromboplastin time (p=.025) were risk factors of unplanned reoperation for thoracic degenerative disease. Whereas American Society of Anesthesiologists (ASA) grade III (p=.015), combined approach (p=.016), and operation time longer than 420 min (p=.042) for spinal tumor, and similar ankylosing spondylitis (p=.023) and operation time longer than 340 min (p=.041) were risk factors of unplanned reoperation for kyphosis deformity.

CONCLUSIONS

The unplanned reoperation rate for thoracic spine surgery was 3.30%, with epidural hematoma and wound complications being the most common reasons. However, upper thoracic spine surgery, concomitant dekyphosis, underlying coagulation disorder, longer operation time, higher ASA grade, and comorbidities of ankylosing spondylitis led to an increased risk of unplanned reoperation within 30 days of thoracic spine surgery.

Incidences, causes and risk factors of unplanned reoperations within 30 days of spine surgery: a single-center study based on 35,246 patients

BACKGROUND CONTEXT

Unplanned reoperation, a quality indicator in spine surgery, has not been sufficiently investigated in a large-scale, single-center study.

PURPOSE

To assess the incidences, causes, and risk factors of unplanned reoperations within 30 days of spine surgeries in a single-center study.

STUDY DESIGN

Retrospective observational study.

PATIENT SAMPLE

A cohort of 35,246 patients who underwent spinal surgery in our hospital were included.

OUTCOME MEASURES

The rates, chief reasons, and risk factors for unplanned reoperations within 30 days of spine surgery.

METHODS

We retrospectively analyzed the data for patients who underwent spine surgeries for degenerative spinal disorders, tumor, or deformity and had subsequent unplanned operations within 30 days at a single tertiary academic hospital from January 2016 to July 2021. Univariate and multivariate analyses were performed to assess the incidences, causes, and risk factors.

RESULTS

Out of 35,246 spinal surgery patients, 297 (0.84%) required unplanned reoperations within 30 days of spine surgery. Patients with a thoracic degenerative disease (3.23%), spinal tumor (1.63%), and spinal deformity (1.50%) had significantly higher rates of reoperation than those with atlantoaxial (0.61%), cervical (0.65%), and lumbar (0.82%) degenerative disease. The common causes for reoperation included epidural hematoma (0.403%), wound infections (0.148%), neurological deficit (0.108%), and pedicle screw malposition (0.077%). Unplanned reoperations were classified as hyperacute (45.45%), acute (30.98%), subacute (15.82%), or chronic (7.74%). Univariate analysis indicated that 20 clinical factors were associated with unplanned reoperation (p<.05). Multivariate Poisson regression analysis revealed that anemia (p<.001), osteoporosis (p=.048), ankylosing spondylitis (p=.008), preoperative foot drop (p=.011), deep venous thrombosis (p<.001), and previous surgical history (p<.001) were independent risk factors for unplanned spinal reoperation.

CONCLUSIONS

The incidence of unplanned spinal reoperations was 0.84%. The chief common causes were epidural hematoma, wound infections, neurological deficit, and pedicle screw malposition. Anemia, osteoporosis, ankylosing spondylitis, preoperative foot drop, deep venous thrombosis, and previous surgical history led to an increased risk of unplanned reoperation within 30 days of spine surgery.

Incidence and risk factors for early and late reoperation following lumbar fusion surgery

STUDY DESIGN

Retrospective cohort study.

PURPOSE

The aim of our study was to determine the rates and indications of reoperations following primary lumbar fusion, as well as the independent risk factors for early and late reoperation.

METHODS

We retrospectively reviewed patients who underwent lumbar fusion surgery between January 2017 and March 2020. All patients were followed up for more than 2 years. Characteristics, laboratory tests, primary diagnosis and surgery-related variables were compared among the early reoperation (< 3 months), the late reoperation (> 3 months) and the non-reoperation groups. Multivariable logistic regression analysis was used to identify independent risk factors for early and late reoperations.

RESULTS

Of 821 patients included in our studies, 34 patients underwent early reoperation, and 36 patients underwent late reoperation. The cumulative reoperation rate was about 4.1% (95% CI 3.8-4.5%) at 3 months, 6.2% (95% CI 5.9-6.5%) at 1 year and 8.2% (95% CI 8.0-8.5%) at 3 years. Multivariable analysis indicated that osteoporosis (odds ratio [OR] 3.6, 95% CI 1.2-10.5, p = 0.02) and diabetes (OR 2.1, 95% CI 1.1-4.5, p = 0.04) were independently associated with early reoperation and multilevel fusion (OR 2.4, 95% CI 1.1-5.4, p = 0.03) was independently associated with late reoperation.

CONCLUSIONS

The most common reasons for early reoperation and late operation were surgical site infection and adjacent segment diseases, respectively. Osteoporosis and diabetes were independent risk factors for early reoperation, and multilevel fusion was independent risk factor for late reoperation. Surgeons should pay more attention to these patients, and future studies should consider the effects of follow-up periods on results.

[Reasons analysis on unplanned reoperation of degenerative lumbar spine diseases]

Objective

To review the research on the reasons of unplanned reoperation (URP) for degenerative lumbar spine diseases, and to provide new ideas for improving the quality of surgery for degenerative lumbar spine diseases.

Methods

The literature about the URP of degenerative lumbar spine diseases at home and abroad in recent years was reviewed and analyzed.

Results

At present, the reasons for URP include surgical site infection (SSI), hematoma formation, cerebrospinal fluid leakage (CSFL), poor results of surgery, and implant complications. SSI and hematoma formation are the most common causes of URP, which happen in a short time after surgery; CSFL also occurs shortly after surgery but is relatively rare. Poor surgical results and implant complications occurred for a long time after surgery. Factors such as primary disease and surgical procedures have an important impact on the incidence of URP.

Conclusion

The main reasons for URP are different in various periods after lumbar spine surgery. Interventions should be given to patients with high-risk URP, which thus can reduce the incidence of URP and improve the surgery quality and patients' satisfaction.

Complications rate of and risk factors for the unplanned reoperation of degenerative lumbar spondylolisthesis in elderly patients: a retrospective single-Centre cohort study of 33 patients

Background

The study was to investigate the complications rate of and risk factors for unplanned reoperation among elderly patients who underwent posterior lumbar fusion (PLF) for degenerative lumbar spondylolisthesis (DLS).

Methods

A total of 1100 DLS patients who were older than 60 years were reviewed from January 2006 to December 2016. 33 patients underwent unplanned reoperations and were analysed and divided into two groups (group A: posterolateral fusion, 650 patients; group B: intervertebral fusion, 450 patients). Sex, body mass index (BMI), radiographic data and clinical outcome data were analysed to evaluate the complications rate of and the risk factors for unplanned reoperations.

Results

A total of 33 patients underwent unplanned reoperations (3%). The patients were followed up for an average of 4.20 ± 2.25 years (group A) and 4.32 ± 2.54 years (group B) without a significant difference. Significant differences were found in mean age, levels of involvement, hospital stay, surgery time, and blood loss between the groups. The causes of unplanned operation were wound infection, screw misplacement, neurological deficit, nonunion, and screw fracture, which were significant except for wound infection between the groups. Higher BMI (obesity), diabetes mellitus (DM), more bleeding and sex (female) were risk factors for complications. Cases of screw misplacement, neurological deficit, nonunion and screw fracture in group A were more significant than those in group B.

Conclusion

Patients with higher BMI, DM, older age, posterolateral fusion, and female sex predicted a higher incidence of unplanned reoperations. Spine surgeons may need to pay more attention to their preoperative training and to improving surgical techniques that could reduce the reoperation rate.

Repeat decompression and fusions following posterolateral fusion versus posterior/transforaminal lumbar interbody fusion for lumbar spondylosis: a national database study

There is a low incidence of reoperation after surgery. It is difficult to detect statistical differences between reoperation rates of different lumbar fusion surgeries. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge. The purpose is to compare the repeat decompression and fusion rate after surgery for degenerative lumbar diseases according to different surgical fusion procedures based on national population-based databases and elucidate the risk factor for repeat decompression and fusions. The Korean Health Insurance Review & Assessment Service database was used. Patients diagnosed with degenerative lumbar diseases and who underwent single-level fusion surgeries between January 1, 2011, and June 30, 2016, were included. They were divided into two groups based on procedure codes: posterolateral fusion or posterior/transforaminal lumbar interbody fusion. The primary endpoint was repeat decompression and fusion. Age, sex, the presence of diabetes, osteoporosis, associated comorbidities, and hospital types were considered potential confounding factors. The repeat decompression and fusion rate was not different between the patients who underwent posterolateral fusion and those who underwent posterior/transforaminal lumbar interbody fusion. Old age, male sex, and hospital type were noted to be risk factors. The incidence of repeat decompression and fusion was independent on the fusion method.

Liver disease is an independent predictor of poor 30-day outcomes following surgery for degenerative disease of the cervical spine

BACKGROUND AND CONTEXT

The impact of underlying liver disease on surgical outcomes has been recognized in a wide variety of surgical disciplines. However, less empiric data are available about the importance of liver disease in spinal surgery.

PURPOSE

To measure the independent impact of underlying liver disease on 30-day outcomes following surgery for the degenerative cervical spine.

STUDY DESIGN

Retrospective comparative study.

PATIENT SAMPLE

A cohort of 21,207 patients undergoing elective surgery for degenerative disease of the cervical spine from the American College of Surgeons National Surgical Quality Improvement Program.

OUTCOME MEASURES

Outcome measures included mortality, hospital length of stay, and postoperative complications within 30 days of surgery.

METHODS

The NSQIP dataset was queried for patients undergoing surgery for degenerative disease of the cervical spine from 2006 to 2015. Assessment of underlying liver disease was based on aspartate aminotransferase-to-platelet ratio index and Model of End-Stage Liver Disease-Sodium scores, computed from preoperative laboratory data. The effect of liver disease on outcomes was assessed by bivariate and multivariate analyses, in comparison with 16 other preoperative and operative factors.

RESULTS

Liver disease could be assessed in 21,207 patients based on preoperative laboratory values. Mild liver disease was identified in 2.2% of patients, and advanced liver disease was identified in 1.6% of patients. The 30-day mortality rates were 1.7% and 5.1% in mild and advanced liver diseases, respectively, compared with 0.6% in patients with healthy livers. The 30-day complication rates were 11.8% and 31.5% in these patients, respectively, compared with 8.8% in patients with healthy livers. In multivariate analysis, the presence of any liver disease (mild or advanced) was independently associated with an increased risk of mortality (OR=2.00, 95% CI=1.12-3.55, p=.019), morbidity (OR=1.35, 95% CI=1.07-1.70, p=.012), and length of hospital stay longer than 7 days (OR=1.73, 95% CI=1.40-2.13, p<.001), when compared with 18 other preoperative and operative factors. Liver disease was also independently associated with perioperative respiratory failure (OR=1.80, 95% CI=1.21-2.68, p=.004), bleeding requiring transfusion (OR=1.43, 95% CI=1.01-2.02, p=.044), wound disruption (OR=2.82, 95% CI=1.04-7.66, p=.042), and unplanned reoperation (OR=1.49, 95% CI=1.05-2.11, p=.025).

CONCLUSIONS

Liver disease independently predicts poor perioperative outcome following surgery for degenerative disease of the cervical spine. Based on these findings, careful consideration of a patient's underlying liver function before surgery may prove valuable in surgical decision-making, preoperative patient counseling, and postoperative patient care.

Impact of Hemodialysis on Surgical Outcomes and Mortality Rate after Lumbar Spine Surgery: A Matched Cohort Study

Introduction

Despite ongoing improvements in both dialysis and surgical techniques, spinal surgery in patients undergoing hemodialysis (HD) is a challenge to surgeons because of the high mortality rate. However, no previous studies have examined clinical outcomes after lumbar surgery in HD patients. The purpose of this study is to compare clinical outcomes and complication rates after lumbar spinal surgery in patients with or without hemodialysis.

Methods

This retrospective, matched cohort study was conducted to compare surgical outcomes between HD vs non-HD patients who underwent lumbar surgery at our hospital. Controls were individually matched to cases at a ratio of 1:2. Clinical outcomes, complications, and mortality rates were compared between the two groups.

Results

Twenty-nine patients in the HD group and 57 in the non-HD group were included in the current study. Five patients in the HD group died during the follow-up period, whereas no patients died in the non-HD group (mortality rate, 17.2% vs. 0%, P = 0.003). Japanese Orthopaedic Association (JOA) scores were significantly less improved in the HD group than in the non-HD group (11.9 vs. 14.2 preoperatively, P = 0.001; 19.9 vs. 25.1 at final follow-up, P < 0.001). Five patients underwent repeat surgery in the HD group, which was significantly higher than the non-HD group (17.2% vs. 3.5%, P = 0.041).

Conclusions

The current study indicates that patients undergoing HD had poor outcomes after lumbar spinal surgery. Moreover, 5 of 29 patients died within a mean 2.4-years follow-up. The indications for lumbar spine surgery in HD patients must be carefully considered because of poor surgical outcomes and high mortality rate.

Reoperation Rates Following Instrumented Lumbar Spine Fusion

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

This study evaluated the cumulative reoperation rate and indications for reoperation following instrumented lumbar spine fusion (LSF).

SUMMARY OF BACKGROUND DATA

LSF reduces disability and improves health-related quality of life for patients with several spinal disorders. The rate of instrumented LSF has drastically increased over the last few decades. The increased incidence of LSF, however, has led to increased reoperation rates.

METHODS

The data are based on the prospective LSF database of Tampere University Hospital that includes all elective indications for LSF surgery. A total of 433 consecutive patients (64% women, mean age 62 years) who underwent LSF in Tampere University Hospital between 2008 and 2011 were evaluated and indications for reoperations were rechecked from patient records and radiographs. The most common diagnosis for the primary surgery was degenerative spondylolisthesis and the mean follow-up time was 3.9 years. The cumulative incidence of reoperations and the "time to event" survival rate was calculated by Kaplan-Meier analysis.

RESULTS

By the end of 2013, 81 patients had undergone at least one reoperation. The cumulative reoperation rate at 2 years was 12.5% (95% confidence interval: 95% CI: 9.7-16.0) and at 4 years was 19.3% (95% CI: 15.6-23.8). The most common pathology leading to reoperation was adjacent segment pathology with a cumulative reoperation rate of 8.7% (95% CI: 6.1-12.5) at 4 years. The corresponding rates for early and late instrumentation failure were 4.4% (95% CI: 2.7-7.0) and 2.9% (95% CI: 1.9-7.1), respectively, and for acute complications, 2.5% (95% CI: 1.4-4.5).

CONCLUSION

Although previous studies reported that early results of spinal fusion are promising, one in five patients required reoperation within 4 years after surgery. Patients and surgeons should be aware of the reoperation rates when planning fusion surgery.

LEVEL OF EVIDENCE

4.