Synergistic effect of independent risk factors for post-endoscopic retrograde cholangiopancreatography pancreatitis: a multicenter retrospective study in Japan

Background/Aims

This study aimed to examine the synergistic effect of independent risk factors on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP).

Methods

This multicenter retrospective study included 1,273 patients with native papillae who underwent ERCP for bile dust stones in Japan. Independent PEP risk factors were identified using univariate and multivariate analyses. Significant risk factors for PEP in the multivariate analysis were included in the final analysis to examine the synergistic effect of independent risk factors for PEP.

Results

PEP occurred in 45 of 1,273 patients (3.5%). Three factors including difficult cannulation ≥10 minutes, pancreatic injection, and normal serum bilirubin level were included in the final analysis. The incidences of PEP in patients with zero, one, two, and three factors were 0.5% (2/388), 1.9% (9/465), 6.0% (17/285), and 12.6% (17/135), respectively. With increasing risk factors for PEP, the incidence of PEP significantly increased (1 factor vs. 2 factors, p=0.006; 2 factors vs. 3 factors, p=0.033).

Conclusions

As the number of risk factors for PEP increases, the risk of PEP may not be additive; however, it may multiply. Thus, aggressive prophylaxis for PEP is strongly recommended in patients with multiple risk factors.

Impact of the COVID-19 pandemic on the incidence of surgical site infection after orthopaedic surgery: an interrupted time series analysis of the nationwide surveillance database in Japan

BACKGROUND

During the COVID-19 pandemic, hygiene awareness was increased in communities and hospitals. However, there is controversy regarding whether such circumstances affected the incidence of surgical site infections (SSIs) in the orthopaedic surgical field.

AIM

To examine the impact of the COVID-19 pandemic on the incidence of SSIs after orthopaedic surgery.

METHODS

The medical records of patients having undergone orthopaedic surgery were extracted from the nationwide surveillance database in Japan. The primary outcomes were the monthly incidences of total SSIs, deep or organ/space SSIs, and SSIs due to meticillin-resistant Staphylococcus aureus (MRSA). Interrupted time series analysis was conducted between pre-pandemic (January 2017 to March 2020) and pandemic (April 2020 to June 2021) periods.

RESULTS

A total of 309,341 operations were included. Interrupted time series analysis adjusted for seasonality showed no significant changes in the incidence of total SSIs (rate ratio 0.94 and 95% confidence interval 0.98-1.02), deep or organ/space SSIs (0.91, 0.72-1.15), or SSIs due to MRSA (1.07, 0.68-1.68) along with no remarkable slope changes in any parameter (1.00, 0.98-1.02; 1.00, 0.97-1.02; and 0.98, 0.93-1.03, respectively).

CONCLUSIONS

Awareness and measures against the COVID-19 pandemic did not markedly influence the incidence of total SSIs, deep or organ/space SSIs, or SSIs due to MRSA following orthopaedic surgery in Japan.

Comparison of Outcomes between a Basket Catheter and a Balloon Catheter for Endoscopic Common Bile Duct Stone Removal

INTRODUCTION

Evidence for the outcomes of endoscopic retrograde cholangiopancreatography (ERCP) between a basket catheter and a balloon catheter for endoscopic common bile duct stone (CBDS) removal is lacking. This study aimed to compare ERCP outcomes using a basket catheter and a balloon catheter for endoscopic CBDS removal.

METHODS

This multicenter retrospective study included 904 consecutive patients with native papilla who underwent endoscopic stone removal for CBDS ≤10 mm using a basket catheter and/or a balloon catheter at three institutions in Japan. ERCP outcomes between the basket and balloon groups were compared using inverse probability of treatment weighting (IPTW) method.

RESULTS

ERCP-related adverse events occurred in 6.5% (29/449) and 7.7% (35/455) of patients in the basket and balloon groups, respectively (IPTW-adjusted p = 0.52). The incidences of post-ERCP pancreatitis, cholangitis, and perforation were similar in the basket and balloon groups (3.8% vs. 2.9%, 1.3% vs. 0.9%, and 0.7% vs. 0.7%, respectively). However, bleeding incidences were significantly higher in the balloon group than in the basket group (3.3% vs. 0.7%, IPTW-adjusted p = 0.012). Successful complete stone removal at one ERCP session using a single catheter was achieved in 17.8% (80/449) in the basket group and in 81.3% (370/455) in the balloon group (IPTW-adjusted p < 0.001).

DISCUSSION

A balloon catheter is more likely to complete stone extraction for CBDS ≤10 mm with a single catheter at one endoscopic stone removal session. However, the risk for post-ERCP bleeding is higher in the balloon group than in the basket group.

Post-endoscopic Retrograde Cholangiopancreatography Pancreatitis after Conservative Treatment for Symptomatic Bile Duct Stones

Introduction

Endoscopic retrograde cholangiopancreatography (ERCP) for asymptomatic common bile duct stones (CBDS) has been associated with an increased risk of post-ERCP pancreatitis (PEP). Patients with asymptomatic CBDS at the time of ERCP include those with incidentally discovered CBDS (group A) and previously symptomatic patients with CBDS who became asymptomatic after conservative treatment for symptomatic CBDS, including obstructive jaundice or acute cholangitis (group B). In this study, we aimed to examine PEP risk in group B by comparing PEP risks between groups A, B, and currently symptomatic patients (group C).

Methods

In this multicenter retrospective study, we examined 77 patients in group A, 41 patients in group B, and 1225 patients in group C who had native papillae. PEP incidence rates between asymptomatic patients at the time of ERCP (groups A and B) and symptomatic patients (group C) were compared using one-to-one propensity score matching. Bonferroni's correction analysis was also performed to compare PEP incidence rates among the three groups.

Results

As per our findings, PEP incidence rate in propensity score-matched groups A and B was significantly higher than that of propensity score-matched group C (13.2% [15/114] versus 4.4% [5/114], respectively, P = 0.033). In groups A and B, PEP incidence rates were 11.7% (9/77) and 14.6% (6/41), respectively. PEP risk in group B was similar to that in group A (P = 1.0). PEP incidence in group B was significantly higher than PEP incidence in group C (14.6% (6/41)) vs. 2.9% (35/1225)) (P = 0.005)).

Conclusions

ERCP for previously symptomatic patients with CBDS who became asymptomatic after conservative treatment for symptomatic CBDS may increase the risk of PEP compared with ERCP for currently symptomatic patients. Thus, ERCP should be performed before patients become asymptomatic using conservative treatments if patients can tolerate ERCP procedures.

Unnecessary endoscopic retrograde cholangiopancreatography associated with the spontaneous passage of common bile duct stones into the duodenum: a multicenter retrospective study

BACKGROUND

Unnecessary endoscopic retrograde cholangiopancreatography (ERCP) after spontaneous passage of common bile duct stones (CBDSs) should be avoided. This study aimed to examine the cumulative diagnosis rate and the predictive factors of spontaneous CBDS passage during the interval between the imaging diagnosis and ERCP.

METHODS

This multicenter retrospective study included 1260 consecutive patients with native papilla diagnosed with CBDSs using imaging modalities. Predictive factors and cumulative diagnosis rate of spontaneously passed CBDSs during the interval between imaging diagnosis and ERCP were analyzed.

RESULTS

The overall cumulative diagnosis rate of spontaneous CBDS passage was 6.2% (78/1260) during a mean interval of 5.0 days. In the multivariate analysis, CBDS sized < 6 mm on diagnostic imaging, solitary CBDS on diagnostic imaging, intervals between the imaging diagnosis and ERCP, and nondilated common bile duct (< 10 mm) were the significant factors associated with spontaneous CBDS passage. Specifically, the cumulative diagnosis rate of spontaneous passage was significantly higher in patients with solitary and CBDSs sized < 6 mm than in those with other CBDSs (14.4% [54/376] vs. 2.7% [24/884], P < 0.001). In both the asymptomatic and symptomatic groups, the cumulative diagnosis rate of the spontaneous passage of CBDSs was significantly higher in patients with solitary and CBDSs sized < 6 mm on diagnostic imaging than in those with multiple and/or CBDSs sized ≥ 6 mm on diagnostic imaging during a mean interval of 20.5 and 2.4 days, respectively (asymptomatic group: 22.4% [15/67] vs. 3.5% [4/113], P < 0.001, symptomatic group: 12.6% [39/309] vs. 2.6% [20/771], P < 0.001).

CONCLUSIONS

Solitary and CBDSs sized < 6 mm on diagnostic imaging can often lead unnecessary ERCP due to spontaneous passage. Preliminary endoscopic ultrasonography immediately before ERCP is recommended, especially in patients with solitary and small CBDSs on diagnostic imaging.

Low Detection Rates of Bile Duct Stones During Endoscopic Treatment for Highly Suspected Bile Duct Stones with No Imaging Evidence of Stones

BACKGROUND

The revised American Society for Gastrointestinal Endoscopy (ASGE) guideline 2019 provides the high-risk criteria for suspected common bile duct stones (CBDSs).

AIMS

To evaluate CBDS detection rates during endoscopic retrograde cholangiopancreatography (ERCP) in high-risk patients with suspected CBDSs based on the ASGE guideline 2019.

METHODS

This multicenter retrospective study included 1100 consecutive patients who underwent ERCP for suspected CBDSs with any high-risk criteria based on the revised ASGE guideline 2019: Criterion 1, CBDSs on imaging; Criterion 2, clinical ascending cholangitis; and Criterion 3, total bilirubin exceeding 4 mg/dL and dilated common bile duct on imaging. We compared CBDS detection rates during ERCP based on individual and combined high-risk criteria.

RESULTS

The CBDS detection rates of patients who met any of the criteria, only Criterion 1, and Criteria 2 or 3 were 86.0% (946/1100), 93.4% (113/121), and 50.0% (106/212), respectively. In patients who met Criteria 1 and 2, 1 and 3, 2 and 3, and all criteria, CBDSs were confirmed during ERCP in 95.1% (490/515), 96.2% (25/26), 55.3% (26/47), and 98.4% (186/189), respectively. The CBDS detection rate during ERCP of patients with at least Criterion 1 significantly exceeded that of patients without at least Criterion 1 [95.7% (814/851) vs. 51.0% (132/259), respectively, P < 0.001].

CONCLUSIONS

Patients with CBDS visualization on imaging have very high CBDS detection rates during ERCP. However, performing ERCP on patients with only clinical predictors, such as cholangitis and dilated CBD with total bilirubin exceeding 4 mg/dL, often results in unnecessary ERCP.

Outcomes by Severity of Obesity During Extracorporeal Membrane Oxygenation Support for COVID-19

Purpose

Obesity adversely impacts outcomes during COVID-19 but its relation to mortality in those receiving extracorporeal membrane oxygenation (ECMO) is uncertain.

Methods

A retrospective multicenter study was conducted. Adult patients (≥18 years old) with severe COVID-19 infection placed on ECMO between March 1, 2020 to April 30, 2021, across the United States were included. A web-based database application, REDCap, was utilized to capture clinical characteristics and outcomes. Patients were grouped into tertiles of body mass index (BMI). The primary outcome was in-hospital mortality after ECMO placement assessed by a time-to-event analysis.

Results

Overall 444 patients (age 49, IQR: 38-57 years, 29% female, BMI: 33, IQR: 29-39 kg/m2) from 17 centers comprised the study cohort. Patients that expired during hospitalization had a similar BMI in comparison to those that were discharged (33, IQR: 29-38 vs. 34, IQR: 30-40 kg/m2, p=0.13). BMI across groups was 27, IQR: 25-29 (lowest tertile), 33, IQR: 32-34 (middle tertile), 41, IQR: 38-45 kg/m2 (highest tertile). At 90 days, in-hospital mortality between BMI tertiles was 53%, 59%, and 53%, p=0.99 (figure). After adjustment for clinical covariates including age, sex, presence of preexisting co-morbidities, cardiopulmonary arrest prior to ECMO, serum creatinine and arterial partial pressure of oxygen (PaO2) to inspired oxygen concentration (FiO2) ratio, there was no difference in hospital mortality in the middle (aHR:1.13, CI: 0.79-1.63, p=0.5) and highest (aHR: 1.38, CI: 0.95-2.01, p=0.09) tertiles in comparison to the lowest BMI tertile.

Conclusion

Severity of obesity is not associated with death during hospitalization in patients placed on ECMO for COVID-19

Cardiac magnetic resonance parametric mapping can detect early cardiac involvement of patients with systemic sclerosis

Background

Systemic sclerosis (SSc) is divided into two subtypes, diffuse and limited cutaneous SSc (dcSSc and lcSSc). The dcSSc subtype has more severe internal organ fibrosis than lcSSc. It is unclear whether cardiovascular magnetic resonance (CMR) parametric mapping can detect early cardiac involvement in these two subtypes.

Purpose

To detect cardiac involvement and evaluate differences between the two subtypes, we examined CMR parametric mapping.

Methods

57 consecutive SSc patients (27 dcSSc and 30 lcSSc) who visited our hospital from July 2018 to February 2021 and underwent CMR at 3.0T (Philips) were included. We analyzed myocardial damage using CMR parametric mapping and compared it with clinical data.

Results

Mean disease durations of dcSSc and lcSSc were 4.0±6.5 years and 4.4±8.3 years, respectively. Although there were no significant differences in LVEF (56.8±8.8 vs 59.6±7.2), the left and right atrial volume index were significantly larger in dcSSc compared with lcSSc (all p&lt;0.05). Focal fibrosis as evaluated by late gadolinium enhancement was found in 9 SSc patients (15.7%) and 4 patients had pulmonary hypertension. DcSSc patients had significantly higher mid-ventricular native T1 (1350.8±73.2 vs 1312.9±52.1, p=0.029) and postcontrast T1 values (640.4±59.4 vs 604.6±42.5, p=0.015) as compared to lcSSc, although there were no significant differences in ECV and T2 values. Native T1 values in mid-ventricular septum were positively correlated with E/e' ratio of echocardiography in overall SSc patients and dcSSc patients but not in lcSSc patients (r=0.320, p=0.021; r=0.505, p=0.010; r=0.195, p=0.329). Native T1 values in mid-ventricular septum were also positively correlated with plasma levels of brain natriuretic peptide (BNP) in overall SSc patients and dcSSc patients but not in lcSSc patients (r=0.353, p=0.008; r=0.484, p=0.011; r=0.113, p=0.559).The multiple regression analysis considering age and sex revealed that mid-ventricular septum native T1 was the independent predictor of E/e' in SSc patients (β=0.306, p=0.026), and dcSSc patients (β=0.553, p=0.007) but not in lcSSc patients (β=−0.282, p=0.105). The ROC curve for predicting E/e'≥14, cut-off value of native T1 in mid-ventricular septum was ≥1348.5msec (AUC 0.762; 95% CI 0.571–0.953; sensitivity 80.0%; specificity 68.1%). BNP was significantly higher in patients with native T1≥1348.5 msec compared with native T1&lt;1348.5 (102.8±112.8 vs 45.7±55.7; p=0.014). The interobserver variability of CMR parametric mapping values was excellent in this study.

Conclusion

DcSSc patients showed higher native T1 and larger left and right atrial volume index of CMR than lcSSc patients, suggesting that DcSSc patients had more severe myocardial involvement and left ventricular diastolic dysfunction than lcSSc patients. Early detection of the high native T1 may predict the occurrence of cardiovascular events in the future.

Funding Acknowledgement

Type of funding sources: None. Correlation between native T1 and BNPCorrelation between native T1 and E/e'

Thoracic aortic aneurysm is an independent factor associated with diffuse idiopathic skeletal hyperostosis

Aims

Although we often encounter patients with an aortic aneurysm who also have diffuse idiopathic skeletal hyperostosis (DISH), there are no reports to date of an association between these two conditions and the pathogenesis of DISH remains unknown. This study therefore evaluated the prevalence of DISH in patients with a thoracic aortic aneurysm (AA).

Patients and Methods

The medical records of 298 patients who underwent CT scans for a diagnosis of an AA or following high-energy trauma were retrospectively examined. A total of 204 patients underwent surgery for an AA and 94 had a high-energy injury and formed the non-AA group. The prevalence of DISH was assessed on CT scans of the chest and abdomen and the relationship between DISH and AA by comparison between the AA and non-AA groups.

Results

The prevalence of DISH in the AA group (114/204; 55.9%) was higher than that in the non-AA group (31/94; 33.0%). On multivariate analysis, the factors of AA, male gender, and ageing were independent predictors of the existence of DISH, with odds ratios of 2.9, 1.9, and 1.03, respectively.

Conclusion

This study revealed that the prevalence of DISH is higher in patients with an AA than in those without an AA, and that the presence of an AA significantly influenced the prevalence of DISH. Cite this article: Bone Joint J 2018;100-B:617-21.

A spinner magnetometer for large Apollo lunar samples

We developed a spinner magnetometer to measure the natural remanent magnetization of large Apollo lunar rocks in the storage vault of the Lunar Sample Laboratory Facility (LSLF) of NASA. The magnetometer mainly consists of a commercially available three-axial fluxgate sensor and a hand-rotating sample table with an optical encoder recording the rotation angles. The distance between the sample and the sensor is adjustable according to the sample size and magnetization intensity. The sensor and the sample are placed in a two-layer mu-metal shield to measure the sample natural remanent magnetization. The magnetic signals are acquired together with the rotation angle to obtain stacking of the measured signals over multiple revolutions. The developed magnetometer has a sensitivity of 5 × 10^-7 Am² at the standard sensor-to-sample distance of 15 cm. This sensitivity is sufficient to measure the natural remanent magnetization of almost all the lunar basalt and breccia samples with mass above 10 g in the LSLF vault.

Rotatable Offner imaging system for ellipsometric measurement

To realize high spatial resolution imaging ellipsometric measurement with large field of view, we developed a rotatable Offner system with unit magnification. When the conventional Offner imaging system is tilted relative to the sample plane for the ellipsometric measurement, only a small region of plane is in focus. The rotatable Offner system developed here renders the entire object in focus through all rotations. The performance of the prototype of the Offner system and imaging ellipsometer is tested by generating maps of the ellipsometric parameters Δ and Ψ for samples such as a silicon wafer and a resolution target made of chromium film evaporated on a glass substrate.

Measurement of effect of electron cyclotron heating in a tandem mirror plasma using a semiconductor detector array and an electrostatic energy analyzer

Temporally and spatially resolved soft x-ray and end-loss-electron analyses of the electron cyclotron heated plasmas are carried out by using a semiconductor detector array and an electrostatic energy analyzer in the GAMMA 10 tandem mirror. The flux and the energy spectrum of the end loss electrons are measured by a multi-grid energy analyzer. Recently, the electron cyclotron heating power modulation experiments have been started in order to generate and control the high heat flux and to make the edge localized mode-like intermittent heat load pattern for the divertor simulation studies by the use of these detectors for electron properties.

Alterations in 18F-FDG accumulation into neck-related muscles after neck dissection for patients with oral cancers

BACKGROUND

18F-fluoro-2-deoxy-D-glucose (18F-FDG) accumulations are commonly seen in the neck-related muscles of the surgical and non-surgical sides after surgery with neck dissection (ND) for oral cancers, which leads to radiologists having difficulty in diagnosing the lesions. To examine the alterations in 18F-FDG accumulation in neck-related muscles of patients after ND for oral cancer.

MATERIAL AND METHODS

18F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) in neck-related muscles were retrospectively analyzed after surgical dissection of cervical lymph nodes in oral cancers.

RESULTS

According to the extent of ND of cervical lymph nodes, the rate of patients with 18F-FDG-PET-positive areas increased in the trapezius, sternocleidomastoid, and posterior neck muscles of the surgical and/or non-surgical sides. In addition, SUVmax of 18F-FDG-PET-positive areas in the trapezius and sternocleidomastoid muscles were increased according to the extent of the ND.

CONCLUSIONS

In evaluating 18F-FDG accumulations after ND for oral cancers, we should pay attention to the 18F-FDG distributions in neck-related muscles including the non-surgical side as false-positive findings.

[Clinical examination of cases of radiation proctitis after intensity-modulated radiation therapy for prostate cancer]

In our series of 366 patients who received intensity-modulated radiation therapy (IMRT) for prostate cancer, radiation proctitis developed in 24 patients. We examined the endoscopic evidence and clinical characteristics of radiation proctitis in these patients. The onset time was 2-29 months after treatment, with bloody bowel discharge being the most common symptom (22 cases). Colonoscopy revealed that the lesions tended to be concentrated on the rectal right anterior wall. Severity, according to the Tada classification, was 0b or Ia in 70.8% of all cases. The incidence of radiation proctitis decreased, and the clinical and endoscopic findings showed only mild radiation proctitis after IMRT.

Serine protease inhibitor-6 differentially affects the survival of effector and memory alloreactive CD8-T cells

The clonal expansion of effector T cells and subsequent generation of memory T cells are critical in determining the outcome of transplantation. While cytotoxic T lymphocytes induce direct cytolysis of target cells through secretion of Granzyme-B (GrB), they also express cytoplasmic serine protease inhibitor-6 (Spi6) to protect themselves from GrB that has leaked from granules. Here, we studied the role of GrB/Spi6 axis in determining clonal expansion of alloreactive CD8-T cells and subsequent generation of memory CD8-T cells in transplantation. CD8-T cells from Spi6(-/-) mice underwent more GrB mediated apoptosis upon alloantigen stimulation in vitro and in vivo following adoptive transfer into an allogeneic host. Interestingly, while OT1.Spi6(-/-) CD8 T cells showed significantly lower clonal expansion following skin transplants from OVA mice, there was no difference in the size of the effector memory CD8-T cells long after transplantation. Furthermore, lack of Spi6 resulted in a decrease of short-lived-effector-CD8-cells but did not impact the pool of memory-precursor-effector-CD8-cells. Similar results were found in heart transplant models. Our findings suggest that the final alloreactive CD8-memory-pool-size is independent from the initial clonal-proliferation as memory precursors express low levels of GrB and therefore are independent of Spi6 for survival. These data advance our understanding of memory T cells generation in transplantation and provide basis for Spi6 based strategies to target effector T cells.

Soft x-ray intensity profile measurements of electron cyclotron heated plasmas using semiconductor detector arrays in GAMMA 10 tandem mirror

Temporally and spatially resolved soft x-ray analyses of electron cyclotron heated plasmas are carried out by using semiconductor detector arrays in the GAMMA 10 tandem mirror. The detector array has 16-channel for the measurements of plasma x-ray profiles so as to make x-ray tomographic reconstructions. The characteristics of the detector array make it possible to obtain spatially resolved plasma electron temperatures down to a few tens eV and investigate various magnetohydrodynamic activities. High power electron cyclotron heating experiment for the central-cell region in GAMMA 10 has been started in order to reduce the electron drag by increasing the electron temperature.

Unstable mutant lysozymes are degraded through the interaction with calnexin homolog Cne1p in Saccharomyces cerevisiae

Cne1p is a yeast homolog of calnexin, which is a constituent of endoplasmic reticulum (ER)-associated protein quality control system in mammals. Cne1p may be involved in the degradation of misfolded lysozymes in Saccharomyces cerevisiae. To test this, c-Myc-tagged lysozymes were expressed in CNE1-deficient S. cerevisiae. The expression and secretion of an unstable lysozyme mutant G49N/D66H were enhanced and its intracellular localization was changed in the CNE1-deficient strain. Furthermore, when Cne1p was co-expressed with unstable lysozyme mutants (G49N/D66H, G49N/C76A, and K13D/G49N), its affinity to the misfolded mutant proteins was revealed by co-immunoprecipitation. The interaction with Cne1p was abrogated by the addition of tunicamycin, an inhibitor of N-glycosylation, indicating that N-linked carbohydrates might be necessary for protein binding to Cne1p. These results suggest that in yeasts, Cne1p interacts with misfolded lysozyme proteins possibly causing their retention in the ER and subsequent elimination via ER-associated degradation.

A prospective study of the incidence and outcomes of incidental dural tears in microendoscopic lumbar decompressive surgery

Little information is available about the incidence and outcome of incidental dural tears associated with microendoscopic lumbar decompressive surgery. We prospectively examined the incidence of dural tears and their influence on the outcome six months post-operatively in 555 consecutive patients (mean age 47.4 years (13 to 89)) who underwent this form of surgery. The incidence of dural tears was 5.05% (28/555). The risk factors were the age of the patient and the procedure of bilateral decompression via a unilateral approach. The rate of recovery of the Japanese Orthopaedic Association score in patients with dural tears was significantly lower than that in those without a tear (77.7% vs 87.6%; p < 0.02), although there were no significant differences in the improvement of the Oswestry Disability Index between the two groups. Most dural tears were small, managed by taking adequate care of symptoms of low cerebrospinal fluid pressure, and did not require direct dural repair. Routine MRI scans were undertaken six months post-operatively; four patients with a dural tear had recurrent or residual disc herniation and two had further stenosis, possibly because the dural tear prevented adequate decompression and removal of the fragments of disc during surgery; as yet, none of these patients have undergone further surgery.

Cite this article: Bone Joint J 2014;96-B:641–5.