Economic implications of dural tears in lumbar microdiscectomies: a retrospective, observational study

STUDY DESIGN

Retrospective cohort study. Level of Evidence Level III. Dural tears (DT) are a frequent complication after lumbar spine surgery. With this study we sought to determine the incidence of DT and the related impact on healthcare expenditures after lumbar discectomies. All patients with first-time single level lumbar discectomies at our institution that underwent minimally-invasive surgery from 2015 to 2019 were reviewed. Age, sex, weight, height, body mass index (BMI), costs, revenues, length of stay (LOS), American Society of Anesthesiology (ASA) score, Charlson Comorbidity Index (CCI) and operation time (OT) were assessed. Exclusion criteria were age < 18 years, previous spine surgery, multiple or traumatic disc herniations but also malignant and infectious diseases. The follow-up time was at least 12 months postoperatively. 358 patients with lumbar discectomies were identified and 230 met the inclusion criteria. The DT incidence was 3.5%. The mean costs (p < 0.001), the loss (p < 0.01) and the operation time (p < 0.0001) were found to be significantly higher in the DT group when compared to the control group of patients without a DT. The revenues were not statistically different between both groups (p > 0.05). Further analysis of the control group by profit and loss revealed significantly higher BMI (p < 0.05), LOS (p < 0.0001) and OT (p < 0.0001) in the loss group. DT represent a significant socioeconomic burden in lumbar spine surgery and cause severe secondary complications. The DT-related impact on healthcare expenses is primarily based on significantly higher OT and a higher mean LOS.

The projected increase of vertebral osteomyelitis in Germany implies a demanding challenge for future healthcare management of aging populations

PURPOSE

Since an increase in the occurrence of native vertebral osteomyelitis (VO) is expected and reliable projections are missing, it is urgent to provide a reliable forecast model and make it a part of future health care considerations.

METHODS

Comprehensive nationwide data provided by the Federal Statistical Office of Germany were used to forecast total numbers and incidence rates (IR) of VO as a function of age and gender until 2040. Projections were done using autoregressive integrated moving average model on historical data from 2005 to 2019 in relation to official population projections from 2020 to 2040.

RESULTS

The IR of VO is expected to increase from 12.4 in 2019 to 21.5 per 100,000 inhabitants [95% CI 20.9-22.1] in 2040. The highest increase is predicted in patients over 75 years of age for both men and women leading to a steep increase in absolute numbers, which is fourfold higher compared to patients younger than 75 years. While the IR per age group will not increase any further after 2035, the subsequent increase is due to a higher number of individuals aged 75 years or older.

CONCLUSIONS

Our data suggest that increasing IR of VO will seriously challenge healthcare systems, particularly due to demographic change and increasing proportions of populations turning 75 years and older. With respect to globally fast aging populations, future health care policies need to address this burden by anticipating limitations in financial and human resources and developing high-level evidence-based guidelines for prevention and interdisciplinary treatment.

Preoperative Performance Status Threshold for Favorable Surgical Outcome in Metastatic Spine Disease

BACKGROUND AND OBJECTIVES

Surgical treatment is an integral component of multimodality management of metastatic spine disease but must be balanced against the risk of surgery-related morbidity and mortality, making tailored surgical counseling a clinical challenge. The aim of this study was to investigate the potential predictive value of the preoperative performance status for surgical outcome in patients with spinal metastases.

METHODS

Performance status was determined using the Karnofsky Performance Scale (KPS), and surgical outcome was classified as "favorable" or "unfavorable" based on postoperative changes in neurological function and perioperative complications. The correlation between preoperative performance status and surgical outcome was assessed to determine a KPS-related performance threshold.

RESULTS

A total of 463 patients were included. The mean age was 63 years (range: 22-87), and the mean preoperative KPS was 70 (range: 30-100). Analysis of clinical outcome in relation to the preoperative performance status revealed a KPS threshold between 40% and 50% with a relative risk of an unfavorable outcome of 65.7% in KPS ≤40% compared with the relative chance for a favorable outcome of 77.1% in KPS ≥50%. Accordingly, we found significantly higher rates of preserved or restored ambulatory function in KPS ≥50% (85.7%) than in KPS ≤40% (48.6%; P < .001) as opposed to a significantly higher risk of perioperative mortality in KPS ≤40% (11.4%) than in KPS ≥50% (2.1%, P = .012).

CONCLUSION

Our results underline the predictive value of the KPS in metastatic spine patients for counseling and decision-making. The study suggests an overall clinical benefit of surgical treatment of spinal metastases in patients with a preoperative KPS score ≥50%, while a high risk of unfavorable outcome outweighing the potential clinical benefit from surgery is encountered in patients with a KPS score ≤40%.

Surgery for Vertebral Osteomyelitis Lowers 1-Year Mortality and Failure Rates Compared with Nonsurgical Treatment: A Propensity-Matched Analysis

BACKGROUND

The aim of this study was to determine differences between patients who underwent surgical treatment and those who underwent nonsurgical treatment of vertebral osteomyelitis (VO) and to identify potential factors influencing treatment failure (death and/or recurrence within 1 year).

METHODS

We performed a retrospective analysis of clinical data prospectively collected from patients treated for VO between 2008 and 2020. The decision between surgical and nonsurgical treatment was made for each patient based on defined criteria. A 1:1 propensity score matching was performed to exclude confounders between the 2 treatments. Univariate and multivariable analyses were performed to identify potential risk factors for death and/or recurrence within the first year after VO diagnosis.

RESULTS

Forty-two patients (11.8%) were treated nonsurgically and 313 patients (88.2%) underwent surgery. A higher percentage of the surgically treated patients than the nonsurgically treated patients had an American Society of Anesthesiologists score of >2 (69.0% versus 47.5%; p = 0.007), and the thoracic spine was affected more often in the surgical group (30.4% versus 11.9%; p = 0.013). Endocarditis was detected significantly more often in the nonsurgically treated patients (14.3% versus 4.2%; p = 0.018). The recurrence rate was 3 times higher in the nonsurgically treated patients (16.7% versus 5.4%; p = 0.017), but this difference was no longer detectable after propensity matching. After matching, the nonsurgically treated patients showed an almost 7-fold higher 1-year mortality rate (25.0% versus 3.7%; p = 0.018) and an almost 3-fold higher rate of treatment failure (42.9% versus 14.8%; p = 0.022). Multivariable analysis revealed nonsurgical treatment and bacteremia to be independent risk factors for treatment failure.

CONCLUSIONS

In our matched cohort of patients with VO, surgical intervention resulted in a significantly lower rate of treatment failure (death and/or recurrence within 1 year) compared with nonsurgical intervention. Furthermore, nonsurgical treatment was an independent risk factor for treatment failure.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Prosthetic arthroplasty of the proximal interphalangeal joint using a surface replacing implant (CapFlex-PIP): 3-year outcomes

Level of evidence: IV.

Torque forces of expandable titanium vertebral body replacement cages during expansion and subsidence in the osteoporotic lumbar spine

BACKGROUND

The application of expandable titanium-cages has gained widespread use in vertebral body replacement for indications such as burst fractures, tumors and infectious destruction. However, torque forces necessary for a satisfactory expansion of these implants and for subsidence of them into the adjacent vertebrae are unknown within the osteoporotic spine.

METHODS

Six fresh-frozen human, osteoporotic, lumbar spines were dorsally instrumented with titanium implants (L2-L4) and a partial corpectomy of L3 was performed. An expandable titanium-cage was inserted ventrally and expanded by both residents and senior surgeons until fixation was deemed sufficient, based on haptic feedback. Torque forces for expansion were measured in Nm. Expansion was then continued until cage subsidence occurred. Torque forces necessary for subsidence were recorded. Strain of the dorsal rods during expansion was measured with strain gauges.

FINDINGS

The mean torque force for fixation of cages was 1.17 Nm (0.9 Nm for residents, 1.4 Nm for senior surgeons, p = .06). The mean torque force for subsidence of cages was 3.1 Nm (p = .005). Mean peak strain of the dorsal rods was 970 μm/m during expansion and 1792 μm/m at subsidence of cages (p = .004).

INTERPRETATION

The use of expandable titanium-cages for vertebral body replacement seems to be a primarily safe procedure even within the osteoporotic spine as torque forces required for subsidence of cages are nearly three times higher than those needed for fixation. Most of the expansion load is absorbed by straining of the dorsal instrumentation. Rod materials other than titanium may alter the torque forces found in this study.

Predictors for quality of life, pain and functional outcomes after surgical treatment of metastatic disease in the spine

BACKGROUND

While predictors for postoperative survival in spine tumour patients have been identified, there is limited evidence for predictors of postoperative Quality of Life (QoL), pain and functional outcome.

METHODS

One hundred and fifty-three consecutive patients, who had undergone surgery for symptomatic spinal metastases between June 2016 and April 2019, were interviewed preoperatively and during follow-ups at three, six and 12 months using the EQ-5D-3L, COMI, and ODI questionnaires. Differences in means exceeding the specific Minimal Clinically Important Difference (MCID) values were considered clinically significant.

RESULTS

Thirty-three percent of the patients were reported dead after 12 months. Only one metastasis compared to multiple metastases has 7.9 the Odds for an improved EQ-5D-3L score at three months. No neoadjuvant metastatic irradiation has 6.8 the Odds for the improvement at that time against performed radiation. A preoperative ODI score between 50.1 and 100 has 22.0 times the odds compared to the range from 0 to 50 for an improved EQ-5D-3L after three months, and 12.5 times the odds in favour of improved COMI after three months, and 13.6 times the odds for improvement of ODI at the three-month follow-up. A preoperative COMI score ranging from 5.0 to 10 has 21 times the odds of a COMI between 0 and 5 for an improved EQ-5D-3L score and 11 times the odds for an improved ODI after 12 months. Other predictors showed no statistically significant improvement.

CONCLUSION

An improvement in QoL, pain and spinal function after 12 months can be predicted by a subjective preoperative poor health condition. Impaired spinal function before surgery, a singular metastasis and no previous irradiation is predictive of improved spinal function and quality of life three months after surgery.

Morphometrics of the coronoid process and the radial notch of the ulna: implications for fracture assessment

PURPOSE

A comprehensive analysis of the morphology of fractures of the coronoid process (CP) can aid diagnosis and guide treatment. The involvement of the radial notch of the ulna (RN)-e.g., in anterolateral facet fractures and transverse fractures of the CP-may influence the biomechanical conditions of the proximal radioulnar joint. However, the morphometric relation between the CP and the RN and the extent to what the proximal radioulnar joint can be affected in these types of fractures is unknown.

METHODS

A total of 113 embalmed, cadaveric ulnae were dissected. All soft tissue was removed. Strictly lateral, high-resolution photographs were taken and digitally analyzed. The height of the CP and its relation to the RN was measured. Sex differences and correlations between measured parameters were calculated.

RESULTS

Mean height of the CP was 16 mm (range: 12-23 mm; SD: 2). Mean height of the RN was 16 mm (11-25 mm; 2.2). The 50% mark of the CP corresponded to 18% (0-56%; 11.2) of the height of the RN. No significant differences were found between male and female specimens.

CONCLUSION

The RN of the ulna extends only to a small part to the CP. Transverse or anterolateral fractures of less than 50% of the coronoid process may involve only a small portion of the proximal radioulnar joint.

Does index-level pedicle screw instrumentation affect cage subsidence after vertebral body replacement? - A biomechanical study in human cadaveric osteoporotic specimens

BACKGROUND

Vertebral body replacement is a common surgical procedure for treatment of disorders associated with spinal instability. Therefore, pedicle screws are usually inserted in adjacent vertebrae for stabilization of the posterior column, however, there is lack of evidence whether implantation of index-level pedicle screws is beneficial or not. This biomechanical study aims to investigate the effect of pedicle screw instrumentation on axial stability following vertebral body replacement.

METHODS

Unstable fracture at L3 level was simulated in lumbar spines from six human cadaveric specimens. Then instrumentation was performed one level above / one level below index level in three specimens and further, three specimens were instrumented at index-level (L3) additionaly. Then we used a testing protocol for biomechanical evaluation of axial loading on human cadaveric lumbar spines until cage subsidence occurred.

FINDINGS

Our results show that index-level instrumented spines endured significantly higher load until cage subsidence occurred compared to non-index-level instrumented specimens (p = 0.05).

INTERPRETATION

Our results demonstrate pedicle screw instrumentation at index-level vertebra should be considered when possbile as it may have a protective effect against cage subsidence in patients undergoing vertebral body replacement surgery.

Evaluation of Classification Systems and Their Correlation With Clinical and Quality-of-life Parameters in Patients With Surgically Treated Spondylodiskitis

INTRODUCTION

Surgical classifications for spondylodiscitis (SD) typically include radiologic features and the status of neurologic impairment. Clinical factors such as preoperative pain, function/disability, overall quality of life (QoL), and risk of recurrence and mortality, which are necessary for a comprehensive assessment of SD and measurement of treatment success, are not considered. There is a lack of external validation of SD classifications. The aim of this study was to validate classifications of SD and to correlate these classifications with the above clinical factors.

METHODS

One hundred fourteen patients from a prospective SD register (2008-2020) with available imaging, preoperative neurologic status, backpain, function/disability data (Oswestry Disability Index and Core Outcome Measures Index), QoL data (Short Form 36, European Quality-of-life Questionnaire), and a 1-year follow-up were retrospectively classified according to Akbar, Homagk, and Pola classifications. Interrater reliability, correlation among classifications, and correlation between classifications and QoL were calculated.

RESULTS

Interrater reliability was κ = 0.83 for Akbar, κ = 0.94 for Homagk, and κ = 0.99 for Pola. The correlation of Akbar with Pola and Homagk was moderate (ρ s = 0.47; ρ s = 0.46) and high between Pola and Homagk (ρ s = 0.7). No notable correlation was observed between any of the classifications and preoperative Oswestry Disability Index, Core Outcome Measures Index, QoL, mortality, and recurrence within 1 year. Only a weak correlation was observed between Homagk and preoperative leg pain and back pain.

CONCLUSION

Available SD classifications have a very good interrater reliability and moderate-to-high correlation with each other but lack correlation with preoperative pain, function/disability, and overall QoL. Because these factors are important for a comprehensive assessment of SD in severity, decision making, and prognosis, they should be included in future SD classifications. This could allow for more comprehensive treatment algorithms.

LEVEL OF EVIDENCE

Level II. Diagnostic study = prospective cohort study; development of diagnostic criteria.

DATA AVAILABILITY

The data sets used and analyzed during this study are available from the corresponding author on reasonable request.

Risk Factors for Neurologic Deficits in Patients With Spinal Epidural Abscess: An Analysis of One-Hundred-Forty Cases

STUDY DESIGN

retrospective study.

OBJECTIVES

In addition to surgical treatment of spinal epidural abscesses (SEA), a conservative, medical treatment for patients without acute neurologic deficits has been proposed. However, the risk factors for neurologic deficits are unclear. This study aims to identify factors predisposing patients with SEA to neurological impairment.

METHODS

All patients treated for SEA between 2008 and 2021 were identified from a prospective vertebral-osteomyelitis registry of a tertiary referral centre. Patient demographics, comorbidities, pathogens, degree of osseous destruction, location of SEA and preoperative neurologic status were retrospectively collected. Differences between patients with (Group 1) and without (Group 2) pretreatment neurologic deficits were assessed by univariate and logistic regression analysis.

RESULTS

A total of 140 patients with SEA were included. Forty-three patients (31%) had a neurologic deficit and 97 patients (69%) had no neurologic deficit prior to therapy. The prevalence of diabetes mellitus (35% vs 19%, P = .03), median visual analogue scale leg pain (8 vs 5, P = .01), median American Society of Anesthesiologists (ASA) Score (3 vs 2.6, P = .003) and mean Body-Mass-Index (29 vs 26, P = .02) differed between Group 1 and 2 in univariate analysis. In multivariable analysis, diabetes mellitus (odds ratio = 2.7), female sex (odds ratio = 2.5) and ASA-Score (odds ratio = 2.4) were significant contributors for neurologic deficits.

CONCLUSIONS

In patients with a SEA without neurologic deficits, the ASA score and diabetes mellitus should be considered, especially in female patients. These patients may be at a higher risk for developing a neurologic deficit and may benefit from an early surgical treatment.

Epidemiology of Surgically Treated Spinal Tumors: A Multicenter Surveillance Study of 9686 Patients from the German Spine Registry (DWG Register)

Tumors of the spine are challenging in terms of diagnoses and interdisciplinary treatment. This study was conducted to evaluate and characterize a large multicenter cohort of surgically treated spine tumor patients.Data of the German Spine Society (DWG) were used to characterize a cohort of all surgically treated spine tumor cases that were registered between 2017 and 2021. Subgroup analysis was performed for tumor entity, tumor localization, height of most severely affected segments, surgical treatment, and demographic parameters.In total, there were 9686 cases, of which 6747 were "malignant", 1942 were "primary benign", 180 were "tumor-like lesions", and 488 were "other" spinal tumors. Subgroups showed differences in number of affected segments as well as localization. There were further significant differences in surgical complication rates (p = 0.003), age (p < 0.001), morbidity (p < 0.001), and duration of surgery (p = 0.004).This is a representative study on spinal tumors from a large spine registry and allows for the epidemiological characterization of surgically treated tumor subgroups and quality control of registry data.

Clinical features and outcome of vertebral osteomyelitis after spinal injection: is it worth the price?

PURPOSE

Spinal injections are increasingly used for back pain treatment. Vertebral osteomyelitis (VO) after spinal injection (SIVO) is rare, but patient characteristics and outcome have not been well characterized. The aim of this study was to assess patient characteristics of SIVO in comparison to patients with native vertebral osteomyelitis (NVO) and to determine predictors for 1-year survival.

METHODS

This is a single-center cohort study from a tertiary referral hospital. This is a retrospective analysis of Patients with VO who were prospectively enrolled into a spine registry from 2008 to 2019. Student's t-test, Kruskal-Wallis test or Chi-square test were applied for group comparisons. Survival analysis was performed using a log-rank test and a multivariable Cox regression model.

RESULTS

283 VO patients were enrolled in the study, of whom 44 (15.5%) had SIVO and 239 (84.5%) NVO. Patients with SIVO were significantly younger, had a lower Charlson comorbidity index and a shorter hospital stay compared to NVO. They also showed a higher rate of psoas abscesses and spinal empyema (38.6% [SIVO] vs. 20.9% [NVO]). Staphylococcus aureus (27%) and coagulase-negative staphylococci (CNS) (25%) were equally often detected in SIVO while S. aureus was more frequently than CNS in NVO (38.1% vs. 7.9%).Patients with SIVO (P = 0.04) had a higher 1-year survival rate (Fig. 1). After multivariate analysis, ASA score was associated with a lower 1-year survival in VO.

CONCLUSION

The results from this study emphasize unique clinical features of SIVO, which warrant that SIVO should be estimated as a separate entity of VO.

What Do We Know about Spondylodiscitis in Children? A Retrospective Study

Pediatric spondylodiscitis (PSD) is a rare disease with a major impact on mobility and functional status. Data concerning demographic and microbiological characteristics, clinical course, treatment, and outcome are scarce. Therefore, the aim of this study was to present clinical experiences of a third-level hospital (2009–2019) in PSD and compare these with adult spondylodiscitis (ASD). Of a total of 10 PSD patients, most of the infants presented with unspecific pain such as hip pain or a limping, misleading an adequate diagnosis of spine origin. Eight patients could be treated conservatively whereas surgery was performed in two cases with one case of tuberculous PSD (tPSD). The causative agent was detected in three of the patients. The diagnosis of PSD is often difficult since clinical symptoms are unspecific and causative pathogens often remain undetected. Nevertheless, empirical anti-infective therapy also seems to be effective. Based on recent studies, clinicians should be encouraged to keep the duration of anti-infective therapy in children short. Since comorbidities are not presented in PSD it is unclear which children suffer from PSD; thus, studies are necessary to identify predisposing factors for PSD. In our study, PSD differs from ASD in diagnostic and especially in therapeutic aspects. Therefore, specific guidelines for PSD would be desirable.

Long-term Radiological and Clinical Outcome after Lumbar Spinal Fusion Surgery in Patients with Degenerative Spondylolisthesis: A Prospective 6-Year Follow-up Study

Objective

To assess which radiological alignment parameters are associated with a satisfactory long‐term clinical outcome after performing lumbar spinal fusion for treating degenerative spondylolisthesis.

Methods

This single‐center prospective study assessed the relation between radiological alignment parameters measured on standing lateral lumbar spine radiographs and the patient‐reported outcome using four different questionnaires (COMI, EQ‐5D, ODI and VAS) as primary outcome measures (level of evidence: II). The following spinopelvic alignment parameters were used: gliding angle, sacral inclination, anterior displacement, sagittal rotation, lumbar lordosis, sacral slope, pelvic tilt and pelvic incidence. Furthermore, the length of stay and perioperative complications were documented. Only cases from 2013 to 2015 of low‐grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) were considered. The patients underwent open posterior lumbar fusion surgery by pedicle screw instrumentation and cage insertion. The operative technique was either a posterior lumbar interbody fusion (PLIF) or a transforaminal lumbar interbody fusion (TLIF) performed by three different senior orthopedic surgeons. Exclusion criteria were spine fractures, minimally invasive techniques, underlying malignant diseases or acute infections, previous or multisegmental spine surgery as well as preoperative neurologic impairment. Of 89 initially contacted patients, 17 patients were included for data analysis (11 males, six females).

Results

The data of 17 patients after mono‐ or bisegmental lumbar fusion surgery to treat low‐grade lumbar spondylolisthesis and with a follow‐up time of least 72 months were analyzed. The mean age was 66.7 ± 11.3 years. In terms of complications two dural tears and one intraoperative bleeding occurred. The average body mass index (BMI) was 27.6 ± 4.4 kg/m² and the average inpatient length of stay was 12.9 ± 3.8 days (range: 8–21). The long‐term clinical outcome correlated significantly with the change of the pelvic tilt (r_s = −0.515, P < 0.05) and the sagittal rotation (r_s = −0.545, P < 0.05). The sacral slope was significantly associated with the sacral inclination (r_s = 0.637, P < 0.01) and the pelvic incidence (r_s = 0.500, P < 0.05). In addition, the pelvic incidence showed a significant correlation with the pelvic tilt (r_s = 0.709, P < 0.01). The change of the different clinical scores over time also correlated significantly between the different questionnaires.

Conclusions

The surgical modification of the pelvic tilt and the sagittal rotation are the two radiological alignment parameters that can most accurately predict the long‐term clinical outcome after lumbar interbody fusion surgery.