Surgery for degenerative cervical spine disease in Finland, 1999-2015

Optimizing Wound Healing Following Cervical Spine Surgery

INTRODUCTION

The volume of cervical spine procedures continues to grow. Plastic and reconstructive surgeons (PRSs) commonly address complex wound-related issues in such cases. The present study investigates whether routine PRS closure of cervical spinal wounds improves outcomes compared with those performed without.

METHODS

Data of patients operated on for cervical spine procedures by the senior author (P.J.T.) between January 2016 and June 2023 were analyzed. Only posterior surgical approaches were included. Demographics, medical status, procedure indication, and surgical characteristics were reviewed. Wound-related and medical complications were examined within a 30-day postoperative period, along with incidences of unplanned reoperation or readmission. Outcomes were compared with 12,943 CPT-matched cases reported by the American College of Surgeons National Surgical Quality Improvement Program.

RESULTS

Five hundred eighty-eight cases were included: 511 (87%) were performed for degenerative spine conditions, 60 (10%) for traumatic injuries, 7 (1%) for neoplasms, 7 (1%) for congenital conditions, and 3 (0.5%) for infected cyst management. The PRS group demonstrated a greater prevalence of diabetes (27% vs 22%, P = 0.016) and chronic obstructive pulmonary disease (10% vs 6%, P < 0.001). Those who received PRS closure were less likely to return to the operating room (1% vs 3%, P = 0.005) or experience a wound-related readmission (2% vs 5%, P < 0.001).

CONCLUSION

PRS closure of cervical spine cases minimizes the risk of reoperation and readmission, even among a population with comorbidities known to be associated with wound-related complications. Improved outcomes were especially observed for more complex wounds requiring local flap closure. Thus, there is strong evidence to support PRS involvement in cervical spine surgery.

Paired and matched analysis of neurological outcomes in revision surgery for cervical myelopathy following delayed neurological decline

Background

Delayed neurological decline may be experienced following successful decompression surgery for cervical myelopathy. Our objective was to analyze neurological recovery upon revision surgery with relation to the index procedure and a matched control.

Methods

Fourteen patients underwent both primary and revision decompression at a single academic center. Peri-operative clinical, radiological, and surgical details were retrieved. Neurological outcomes [change in modified Japanese Orthopedic Association (mJOA), recovery ratio] following the second surgery were compared to (I) the primary operation and (II) a control subject receiving primary decompression matched for gender, age, mJOA score, and surgical approach. The minimum clinically important difference (MCID) in mJOA score was set at 2.5.

Results

Revision decompressions were performed 6.8±4.2 years following the index surgery, when patients were 61.4±11.0 years of age. An increase in mJOA score of 2.7±2.0 following revision surgery was similar to that achieved after the primary operation (2.2±2.1, P=0.616). A recovery ratio of 38.1%±25.4% upon revision compared favorably to that following the primary operation (35.0%±37.4%, P=0.867). Non-inferiority testing between revision surgery and the first operation (P=0.02) demonstrated a similar capacity to achieve the MCID as did comparison with matched subjects (P<0.01).

Conclusions

Patients were able to make up for lost neurological gains following revision surgery. Careful selection of cases for revision likely facilitated recovery. Recovery trajectories should be consolidated upon larger sample sizes allowing for identification of prognostic factors.

Tramadol-paracetamol for postoperative pain after spine surgery - A randomized, double-blind, placebo-controlled study

OBJECTIVES

Multimodal pain management is one component in enhanced recovery after surgery protocol. Here we evaluate the efficacy of tramadol-paracetamol in acute postoperative pain and pain outcome at 12 months after spine surgery in randomized, double-blind, placebo-controlled trial.

METHODS

We randomized 120 patients undergoing spine surgery to receive, for add-on pain management, two tramadol-paracetamol 37.5 mg/325 mg (n = 61) or placebo tablets (n = 59) twice a day for 5 postoperative days. In the hospital, multimodal pain management consisted of dexketoprofen and oxycodone. After discharge, patients were prescribed ibuprofen 200 mg, maximum 1,200 mg/day. Pain, analgesic use, and satisfaction with pain medication were followed up with the Brief Pain Inventory questionnaire before surgery and at 1 and 52 weeks after surgery. The primary outcome was patients' satisfaction with pain medication 1 week after surgery.

RESULTS

At 1 week after surgery, patients' satisfaction with pain medication was similarly high in the two groups, 75% [interquartile range, 30%] in the placebo group and 70% [40%] in the tramadol-paracetamol group (p = 0.949) on a scale: 0% =  not satisfied, 100% = totally satisfied. At 1 week, ibuprofen dose was lower in the placebo group 200 mg [1,000] compared to the tramadol-paracetamol group, 800 mg [1,600] (p = 0.016). There was no difference in the need for rescue oxycodone. Patients in the tramadol-paracetamol group had more adverse events associated with analgesics during the first postoperative week (relative risk = 1.8, 95% confidence interval, 1.2-2.6).

CONCLUSION

Add-on pain treatment with tramadol-paracetamol did not enhance patients' satisfaction with early pain management after back surgery.

Microbial spectrum, patient-specific factors, and diagnostics in implant-related postoperative spondylodiscitis

Aims

Implant-related postoperative spondylodiscitis (IPOS) is a severe complication in spine surgery and is associated with high morbidity and mortality. With growing knowledge in the field of periprosthetic joint infection (PJI), equivalent investigations towards the management of implant-related infections of the spine are indispensable. To our knowledge, this study provides the largest description of cases of IPOS to date.

Methods

Patients treated for IPOS from January 2006 to December 2020 were included. Patient demographics, parameters upon admission and discharge, radiological imaging, and microbiological results were retrieved from medical records. CT and MRI were analyzed for epidural, paravertebral, and intervertebral abscess formation, vertebral destruction, and endplate involvement. Pathogens were identified by CT-guided or intraoperative biopsy, intraoperative tissue sampling, or implant sonication.

Results

A total of 32 cases of IPOS with a mean patient age of 68.7 years (37.6 to 84.1) were included. Diabetes, age > 60 years, and history of infection were identified as risk factors. Patient presentation upon admission included a mean body temperature of 36.7°C (36.1 to 38.0), back pain at rest (mean visual analogue scale (VAS) mean 5/10) and when mobile (mean VAS 6/10), as well as elevated levels of CRP (mean 76.8 mg/l (0.4 to 202.9)) and white blood cell count (mean 9.2 units/nl (2.6 to 32.8)). Pathogens were identified by CT-guided or conventional biopsy, intraoperative tissue sampling, or sonication, and Gram-positive cocci presented as the most common among them. Antibiotic therapy was established in all cases with pathogen-specific treatment in 23 (71.9%) subjects. Overall 27 (84.4%) patients received treatment by debridement, decompression, and fusion of the affected segment.

Conclusion

Cases of IPOS are rare and share similarities with spontaneous spondylodiscitis. While procedures such as CT-guided biopsy and sonication are valuable tools in the diagnosis of IPOS, MRI and intraoperative tissue sampling remain the gold standard. Research on known principles of PJI such as implant retention versus implant exchange need to be expanded to the field of spine surgery.

The Finnish spine register (FinSpine): development, design, validation and utility

PURPOSE

Our aim was to develop a nationwide, computer-based, Spine Register (FinSpine) for monitoring surgical activity, quality of surgery, long-term outcomes, and effectiveness of treatment. In this paper, we describe our experiences in the development and implementation of the register.

METHODS

The register was developed by a steering group, consisting of orthopedic surgeons and neurosurgeons from the whole country. We strived to develop a register which would be in active use by spine surgeons and enable collection of Patient Reported Outcome and Experience Measures (PROMs and PREMs) automatically and prospectively. We are actively promoting the use of the register in order to gain a nationwide coverage and achieve high response-rates from both surgeons and patients.

RESULTS

The use of FinSpine started in 2016 and it has been granted continuous funding from the Finnish Institute for Health and Welfare from the 1st of January 2023 onwards. Currently the register is used by 19/23 (83%) public hospitals and the use is expanding to private hospitals as well. The response-rate of surgeons is currently 80%. The response-rate of patients is on average 56% but reaches up to 90% in hospitals using register-coordinators.

CONCLUSION

The use of FinSpine is increasing. By gaining a larger coverage and completeness, the data can be used for research purposes which we believe will influence decision making and ultimately improve the outcomes and quality of life of the patients. Comparison with other national spine registers is possible, since FinSpine includes similar baseline characteristics and outcome measures (e.g., ODI, EQ-5D, VAS).

Incidence of spine surgery in the South African private healthcare sector: ten-year trends within a large open medical scheme

PURPOSE

Studies from developed countries suggest a dramatic increase in the utilization of spine surgery in recent decades, however less is known about spine surgery rates in the developing world. The aim of this study was to investigate ten-year trends in the incidence of spine surgery within South Africa's largest open medical scheme.

METHODS

This retrospective review included adult inpatient spine surgeries funded by the scheme between 2008 and 2017. The incidence of spine surgery was investigated by age group-overall and for degenerative pathologies, fusion and instrumentation. Surgeons per 100,000 members were determined. Trends were evaluated by linear regression and by crude 10-year change in incidence.

RESULTS

A total of 49,575 spine surgeries were included. The incidence of surgery for lumbar degenerative pathology showed a significant upward trend among 60-79 year olds but declined among 40-59 year olds. The incidence of lumbar fusion and lumbar instrumentation declined significantly among 40-59 year olds with little change among 60-79 year olds. The ratio of orthopaedic spinal surgeons decreased from 10.2 to 6.3 per 100,000 members whereas the ratio of neurosurgeons decreased from 7.6 to 6.5 per 100,000.

CONCLUSION

Spine surgery in the South African private healthcare sector bears some similarity to developed countries in that it is dominated by elective procedures for degenerative pathology. However, the findings did not reflect the marked increases in the utilization of spine surgery reported elsewhere. It is hypothesized that this may be partly related to differences in the supply of spinal surgery.

Change in functioning profile after cervical surgery

The objectives are to (a) introduce an approach to use the Neck Disability Index (NDI) in a way, which is different and more International Classification of Functioning, Disability and Health-oriented than acommon practice - focusing on functional profile instead of composite score only, and (b) to describe the changes in functioning experienced by patients undergoing cervical surgery. This was a register-based study of almost 400 patients undergoing different cervical surgical procedures in a university hospital between 2018 and 2021. The patients responded to repeated surveys preoperatively and 3, 12 and 24 months postoperatively. Linear regression test was performed to analyze the change of the NDI score. The changes in scores during a follow-up were statistically significant ( P < 0.001) for all the NDI items as well as for the total score. Each item demonstrated significant improvement postoperatively and a slight worsening between 1 and 2 years after the surgery. The observed slight decline in functioning at the end of follow-up remained below the baseline level for all the items. While the change in the composite score of the NDI was able to describe the overall change in functioning after the surgery, different areas of functioning were affected by the surgery differently. The results suggest that the use of functional profiles, in addition to composite scores, is justified among patients with cervical pathologies.

Incidence and risk factors of spinal cord stimulation for persistent or recurrent pain after lumbar spine surgery: a population-based study

PURPOSE

This study aims to elucidate the incidence of and independent risk factors for spinal cord stimulator implantations for patients who underwent lumbar spine surgery.

METHODS

The PERFormance, Effectiveness, and Cost of Treatment (PERFECT) episodes database, which was established for selected diseases and procedures in Finland, includes all patients who underwent lumbar spine surgery for degenerative spine conditions or spinal cord stimulation (SCS) in Finland from 1986 to 2018. The data on age, sex, hospital diagnoses, surgical procedures, and causes of death were imported from the Finnish national registers into the PERFECT database.

RESULTS

Between 1986 and 2018, 157,824 patients had their first lumbar spine procedure and for 1769 (1.1%) of them, a subsequent SCS procedure was observed during the follow-up. The cumulative incidence of SCS for persistent or recurrent pain after lumbar disk herniation, spinal stenosis, degenerative disk disease, and spondylolysis and spondylolisthesis surgery at 15 years was 1.2%, 1.0%, 2.7%, and 2.6% respectively. At 15 years, the cumulative incidence of SCS for persistent or recurrent pain after lumbar spine surgery after five or more lumbar spinal operations was 11.9%.

CONCLUSION

Repeated surgery was the most prominent significant risk factor for SCS for persistent or recurrent pain after lumbar spine surgery. The risk of SCS for persistent or recurrent pain after lumbar spine surgery increases significantly along with the number of lumbar spine procedures. When considering repeated lumbar spine surgery, careful evaluation of treatment options should take place to ensure good patient outcomes.

A nationwide study of patients operated for cervical degenerative disorders in public and private hospitals

During the last decades, there has been an increase in the rate of surgery for degenerative disorders of the cervical spine and in the use of supplementary private health insurance. Still, there is limited knowledge about the differences in characteristics of patients operated in public and private hospitals. Therefore, we aimed at comparing sociodemographic-, clinical- and patient management data on patients operated for degenerative cervical radiculopathy and degenerative cervical myelopathy in public and private hospitals in Norway. This was a cross-sectional study on patients in the Norwegian Registry for Spine Surgery operated for degenerative cervical radiculopathy and degenerative cervical myelopathy between January 2012 and December 2020. At admission for surgery, we assessed disability by the following patient reported outcome measures (PROMs): neck disability index (NDI), EuroQol-5D (EQ-5D) and numerical rating scales for neck pain (NRS-NP) and arm pain (NRS-AP). Among 9161 patients, 7344 (80.2%) procedures were performed in public hospitals and 1817 (19.8%) in private hospitals. Mean age was 52.1 years in public hospitals and 49.7 years in private hospitals (P < 0.001). More women were operated in public hospitals (47.9%) than in private hospitals (31.6%) (P < 0.001). A larger proportion of patients in private hospitals had high education (≥ 4 years of college or university) (42.9% vs 35.6%, P < 0.001). Patients in public hospitals had worse disease-specific health problems than those in private hospitals: unadjusted NDI mean difference was 5.2 (95% CI 4.4 – 6.0; P < 0.001) and adjusted NDI mean difference was 3.4 (95% CI 2.5 – 4.2; P < 0.001), and they also had longer duration of symptoms (P < 0.001). Duration of surgery (mean difference 29 minutes, 95% CI 27.1 – 30.7; P < 0.001) and length of hospital stay (mean difference 2 days, 95% CI 2.3 – 2.4; P < 0.001) were longer in public hospitals. In conclusion, patients operated for degenerative cervical spine in private hospitals were healthier, younger, better educated and more often men. They also had less and shorter duration of symptoms and seemed to be managed more efficiently. Our findings indicate that access to cervical spine surgery in private hospitals could be skewed in favour of patients with higher socioeconomic status.

The Relation of Patient Expectations, Satisfaction, and Outcome in Surgery of the Cervical Spine: A Prospective Study

STUDY DESIGN

We performed a prospective nonblinded single center observational study.

OBJECTIVE

To investigate the relationship between expectations, outcome, and satisfaction with the outcome in patients undergoing cervical spine stabilization surgery.

SUMMARY OF BACKGROUND DATA

In modern healthcare, patient-reported outcome measures and patient satisfaction have become an important aspect of quality control. Therefore, outcome benchmarks for specific diseases are highly desired. Numerous studies have investigated patient-reported outcome measures and what constitutes satisfaction in degenerative lumbar spine disease. In cervical spine surgery, it is less clear what drives the postoperative symptom burden and patient satisfaction and how this depends on the primary diagnosis and other patient factors.

METHODS

This was a prospective, single center, observational study on patients undergoing cervical spine stabilization surgery for degenerative disease, trauma, infection, or tumor. Using the visual analogue scale for neck and arm pain, the neck disability index (NDI), the modified Japanese Orthopedic Association Score (mJOA) and patient-reported satisfaction, patient status and expectations before surgery, at discharge, 6 and 12 months after surgery were evaluated.

RESULTS

One hundred five patients were included. Score-based outcome correlated well with satisfaction at 6 and 12 months. Except for low NDI expectations (≥15 points) that correlated with dissatisfaction, expectations in no other score were correlated with satisfaction. Expectations did influence the outcome in some subgroups and meeting expectations resulted in higher rates of satisfaction. Pain reduction plays an important role for satisfaction, independently from the predominant symptom or pathology.

CONCLUSION

Satisfaction correlates well with outcome. Meeting expectations did influence satisfaction with the outcome. The NDI seems to be a valuable preoperative screening tool for poor satisfaction at 12 months. In degenerative pathology, pain is the predominant variable influencing satisfaction independently from the predominant symptom (including myelopathy).

LEVEL OF EVIDENCE

5.

Hospitalisation for degenerative cervical myelopathy in England: insights from the National Health Service Hospital Episode Statistics 2012 to 2019

PURPOSE

Degenerative cervical myelopathy (DCM) is the most common cause of adult spinal cord dysfunction worldwide. However, the current incidence of DCM is poorly understood. The Hospital Episode Statistics (HES) database contains details of all secondary care admissions across NHS hospitals in England. This study aimed to use HES data to characterise surgical activity for DCM in England.

METHODS

The HES database was interrogated for all cases of DCM between 2012 and 2019. DCM cases were identified from 5 ICD-10 codes. Age-stratified values were collected for 'Finished Consultant Episodes' (FCEs), which correspond to a patient's hospital admission under a lead clinician. Data was analysed to explore current annual activity and longitudinal change.

RESULTS

34,903 FCEs with one or more of the five ICD-10 codes were identified, of which 18,733 (53.6%) were of working age (18-64 years). Mean incidence of DCM was 7.44 per 100,000 (SD ± 0.32). Overall incidence of DCM rose from 6.94 per 100,000 in 2012-2013 to 7.54 per 100,000 in 2018-2019. The highest incidence was seen in 2016-2017 (7.94 per 100,000). The median male number of FCEs per year (2919, IQR: 228) was consistently higher than the median female number of FCEs per year (2216, IQR: 326). The rates of both emergency admissions and planned admissions are rising.

CONCLUSIONS

The incidence of hospitalisation for DCM in England is rising. Health care policymakers and providers must recognise the increasing burden of DCM and act to address both early diagnoses and access to treatment in future service provision plans.

Prospective, population-based study of occupational movements and postures of the neck as risk factors for cervical disc herniation

OBJECTIVE

We studied the associations between objectively measured occupational neck exposures in a job exposure matrix (JEM) and cervical disc herniation (CDH).

DESIGN

A cohort study of Danish workers who ever held at least one of 29 jobs (eg, dentists, hairdressers, childcare, carpenters) from 1981 to 2016 was formed. Representative whole work-day inclinometric measurements from previous studies using triaxial accelerometers measuring neck angular velocity and posture of the neck were used as exposure in a JEM. Job titles were retrieved from the Danish Occupational Cohort with eXposure data database. The risk of CDH by quintiles of cumulated exposure was assessed by incidence rate ratios (IRR), adjusted for age, sex, calendar-year, previous lumbar disc herniation and educational level, using Poisson regression models.

SETTING

Nationwide Danish registers.

PARTICIPANTS

852 625 Danish workers within 29 different job-titles.

OUTCOME MEASURES

First diagnosis of CDH was retrieved from the Danish National Patient Register.

RESULTS

We found 14 000 cases of CDH during 20.2 million person-years of follow-up. Increasing levels of neck angular velocity showed a decreasing risk with IRR 0.90 (95% CI 0.86 to 0.95) when the highest level of cumulative exposure (dynamic work) was compared with the lowest (static work). Similar results were found for extension and flexion of the neck, though not statistically significant for extension. Multiple sensitivity analyses did not change the results.

CONCLUSION

In this large register-based study based on a JEM, we found no evidence of an increased risk of CDH with increasing cumulated angular velocity, flexion or extension of the neck. Factors other than occupational dynamic neck movements and bent neck position seem to be important in the development of CDH.

Establishing the Socio-Economic Impact of Degenerative Cervical Myelopathy Is Fundamental to Improving Outcomes [AO Spine RECODE-DCM Research Priority Number 8]

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To contextualize AO Spine RECODE-DCM research priority number 5: What is the socio-economic impact of DCM? (The financial impact of living with DCM to the individual, their supporters, and society as a whole).

METHODS

In this review, we introduce the methodology of health-economic investigation, including potential techniques and approaches. We summarize the current health-economic evidence within DCM, so far focused on surgical treatment. We also cover the first national estimate, in partnership with Myelopathy.org from the United Kingdom, of the cost of DCM to society. We then demonstrate the significance of this question to advancing care and outcomes in the field.

RESULTS

DCM is a common and often disabling condition, with a significant lack of recognition. While evidence demonstrates the cost-effectives of surgery, even among higher income countries, health inequalities exist. Further the prevalent residual disability in myelopathy, despite treatment affects both the individual and society as a whole. A report from the United Kingdom provides the first cost-estimate to their society; an annual cost of ∼£681.6 million per year, but this is likely a significant underestimate.

CONCLUSION

A clear quantification of the impact of DCM is needed to raise the profile of a common and disabling condition. Current evidence suggests this is likely to be globally substantial.

'Ex Vivo Porcine Models Are Valid for Testing and Training Microsurgical Lumbar Decompression Techniques'

BACKGROUND

Spinal surgeries are the leading causes for patient settlement issues. Recent European Medical Device Regulations aims to reduce complications by enforcing that surgical tools are validated before clinical use. Human cadavers are favored in preclinical use, but due to anatomical variance, decay and scarce supply, alternative synthetic and animal models are used. This study evaluates the fidelity and validity of porcine models in training and assessment of microsurgical decompressive techniques in lumbar spine.

METHODS

Anatomical dimensions of ten human and five young pig spines were assessed from CT images. Novel 'en bloc' fresh-frozen ex vivo porcine model tissues' fidelity and validity for decompressive surgery was evaluated by three expert neurosurgeons, in comparison to other models.

RESULTS

The pig's anatomical dimensions were on average 11% smaller than in humans. The pig's L4-L5 was most alike humans and highest similarity was in lamina and spinous process widths, and skin to posterior longitudinal ligament distance. Dimensional variability was higher in humans (F = 19.06-0.56, p<0.05). The pig's tissues were felt as good as living patients and better than cadavers for skin, fascia, bone, facets, ligamentum flavum and dura, but poor for vessels (experts ICC=0.696-0.903). The pig models validity for assessing drills adverse features (friction, jitter, heating, and soft tissue trauma) were reported unanimously excellent.

CONCLUSION

Pigs are representative for assessing microsurgical decompression techniques in the lower lumbar spine. The novel 'en bloc' pig model can be an asset for industries and clinicians during assessment and training of new spinal techniques.

Mortality of older patients with dementia after surgery for chronic subdural hematoma: a nationwide study

BACKGROUND

dementia is associated with an excess risk of death but mortality after chronic subdural hematoma (CSDH) evacuation in older people with dementia is unknown. We assessed the association between dementia and 1-year case-fatality in older persons undergoing CSDH evacuation.

METHODS

we conducted a nationwide Finnish cohort study including all older persons (≥60 years) undergoing CSDH evacuation during 1997-2014 (referred to as cases). We identified controls, without a diagnosis of CSDH, that were matched for age, sex and year of first hospitalisation with a new dementia diagnosis. We identified cases and controls with a pre-existing diagnosis of dementia. Outcome was 12-month mortality. Mortality was compared in case-only and case-control analyses.

RESULTS

of 7,621 included cases, 885 (12%) had a pre-existing diagnosis of dementia. The proportion of cases increased from 9.7% in 1997-2002 to 12.2% in 2012-2014 (P = 0.038 for trend). In the case-analysis, dementia independently associated with 1-year case-fatality (dementia vs. no dementia odds ratio [OR] 1.50, 95% confidence interval [CI] 1.26-1.78). Sensitivity analysis suggested the association to be strongest for those 60-69 years old (OR 3.21, 95% CI 1.59-6.47). In the case-control matched analysis, 1-year mortality was 26% in the dementia CSDH surgery group compared to 16% in the dementia non-CSDH controls (P < 0.001).

CONCLUSION

dementia is a significant risk factor for 1-year mortality after CSDH surgery in older people. The proportion of older CSDH patients having a pre-existing diagnosis of dementia is increasing. Thus, there is a need for improved evidence regarding the indications and benefits of CSDH evacuation among older persons.

Occurrence, Risk Factors, and Time Trends for Late Reoperations due to Degenerative Cervical Spine Disease: A Finnish National Register Study of 19 377 Patients Operated on Between 1999 and 2015

BACKGROUND

Surgery for degenerative cervical spine disease has escalated since the 1990s. Fusion has become the mainstay of surgery despite concerns regarding adjacent segment degeneration. The patient-specific trends in reoperations have not been studied previously.

OBJECTIVE

To analyze the occurrence, risk factors, and trends in reoperations in a long-term follow-up of all the patients operated for degenerative cervical spine disease in Finland between 1999 and 2015.

METHODS

The patients were retrospectively identified from the Hospital Discharge Registry. Reoperations were traced individually; only reoperations occurring >365 d after the primary operation were included. Time trends in reoperations and the risk factors were analyzed by regression analysis.

RESULTS

Of the 19 377 identified patients, 9.2% underwent a late reoperation at a median of 3.6 yr after the primary operation. The annual risk of reoperation was 2.4% at 2 yr, 6.6% at 5 yr, 11.1% at 10 yr, and 14.2% at 15 yr. Seventy-five percent of the late reoperations occurred within 6.5 yr of the primary operation. Foraminal stenosis, the anterior cervical decompression and fusion (ACDF) technique, male gender, weak opiate use, and young age were the most important risk factors for reoperation. There was no increase in the risk of reoperations over the follow-up period.

CONCLUSION

The risk of reoperation was stable between 1999 and 2015. The reoperation risk was highest during the first 6 postoperative years and then declined. Patients with foraminal stenosis had the highest risk of reoperation, especially when ACDF was performed.

Biomechanical Analysis of Allograft Spacer Failure as a Function of Cortical-Cancellous Ratio in Anterior Cervical Discectomy/Fusion: Allograft Spacer Alone Model

The design and ratio of the cortico-cancellous composition of allograft spacers are associated with graft-related problems, including subsidence and allograft spacer failure. Methods: The study analyzed stress distribution and risk of subsidence according to three types (cortical only, cortical cancellous, cortical lateral walls with a cancellous center bone) and three lengths (11, 12, 14 mm) of allograft spacers under the condition of hybrid motion control, including flexion, extension, axial rotation, and lateral bending,. A detailed finite element model of a previously validated, three-dimensional, intact C3–7 segment, with C5–6 segmental fusion using allograft spacers without fixation, was used in the present study. Findings: Among the three types of cervical allograft spacers evaluated, cortical lateral walls with a cancellous center bone exhibited the highest stress on the cortical bone of spacers, as well as the endplate around the posterior margin of the spacers. The likelihood of allograft spacer failure was highest for 14 mm spacers composed of cortical lateral walls with a cancellous center bone upon flexion (PVMS, 270.0 MPa; 250.2%) and extension (PVMS: 371.40 MPa, 344.2%). The likelihood of allograft spacer subsidence was also highest for the same spacers upon flexion (PVMS, 4.58 MPa; 28.1%) and extension (PVMS: 12.71 MPa, 78.0%). Conclusion: Cervical spacers with a smaller cortical component and of longer length can be risk factors for allograft spacer failure and subsidence, especially in flexion and extension. However, further study of additional fixation methods, such as anterior plates/screws and posterior screws, in an actual clinical setting is necessary.

Identifying the Characteristics of Patients With Cervical Degenerative Disease for Surgical Treatment From 17-Year Real-World Data: Retrospective Study

Background

Real-world data (RWD) play important roles in evaluating treatment effectiveness in clinical research. In recent decades, with the development of more accurate diagnoses and better treatment options, inpatient surgery for cervical degenerative disease (CDD) has become increasingly more common, yet little is known about the variations in patient demographic characteristics associated with surgical treatment.

Objective

This study aimed to identify the characteristics of surgical patients with CDD using RWD collected from electronic medical records.

Methods

This study included 20,288 inpatient surgeries registered from January 1, 2000, to December 31, 2016, among patients aged 18 years or older, and demographic data (eg, age, sex, admission time, surgery type, treatment, discharge diagnosis, and discharge time) were collected at baseline. Regression modeling and time series analysis were conducted to analyze the trend in each variable (total number of inpatient surgeries, mean age at surgery, sex, and average length of stay). A P value <.01 was considered statistically significant. The RWD in this study were collected from the Orthopedic Department at Peking University Third Hospital, and the study was approved by the institutional review board.

Results

Over the last 17 years, the number of inpatient surgeries increased annually by an average of 11.13%, with some fluctuations. In total, 76.4% (15,496/20,288) of the surgeries were performed in patients with CDD aged 41 to 65 years, and there was no significant change in the mean age at surgery. More male patients were observed, and the proportions of male and female patients who underwent surgery were 64.7% (13,126/20,288) and 35.3% (7162/20,288), respectively. However, interestingly, the proportion of surgeries performed among female patients showed an increasing trend (P<.001), leading to a narrowing sex gap. The average length of stay for surgical treatment decreased from 21 days to 6 days and showed a steady decline from 2012 onward.

Conclusions

The RWD showed its capability in supporting clinical research. The mean age at surgery for CDD was consistent in the real-world population, the proportion of female patients increased, and the average length of stay decreased over time. These results may be valuable to guide resource allocation for the early prevention and diagnosis, as well as surgical treatment of CDD.

Surgical techniques for degenerative cervical spine in Finland from 1999 to 2015

Purpose

The purpose of this study is to assess the trends and regional variations in the operative techniques used for degenerative or rheumatoid cervical spine disease in Finland between 1999 and 2015.

Methods

The Finnish Hospital Discharge Register (FHDR) was searched for the data on all the primary operations for degenerative cervical spine disease (DCSD) or rheumatoid atlanto-axial subluxation (rAAS). Operative codes were used to identify the patients from the FHDR and combined with diagnosis codes to verify patient inclusion. The patients were classified into three groups: anterior cervical decompression and fusion (ACDF), posterior decompression and fusion (PDF) and decompression.

Results

A total of 19,701 primary operations were included. The adjusted incidence of ACDF rose from 6.5 to 27.3 operations/100,000 adults. ACDF became the favoured technique in all the diagnostic groups except AAS, and by 2015, ACDF comprised 84.5% of the operations. The incidence of PDF for DCSD increased from 0.2 to 0.7/100,000 people. Solely decompressive operations declined from 13.7 to 4.0 operations/100,000 people. The regional differences in the incidence of operations were most marked in the incidence of ACDF, with overall incidences ranging from 11.2 to 37.0 operations/100,000. The distribution of the operative techniques used varied as well.

Conclusions

Between 1999 and 2015, the operative techniques used for DCSD changed from prevalently decompressive to utilising ACDF in 68.8 to 91.0% of the operations, depending on the treating hospital. ACDF became the most commonly applied technique for all degenerative diagnoses except AAS.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-04026-9) contains supplementary material, which is available to authorized users.