Benny Dahl

Prof. Dr. Benny Dahl

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Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2023 in The Bone & Joint Journal
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Journal Article
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LRLærke C. Ragborg
Lærke C. Ragborg
CDCasper Dragsted
Casper Dragsted
SOSøren Ohrt-Nissen
Søren Ohrt-Nissen
TAThomas Andersen
Thomas Andersen
MGMartin Gehrchen
Martin Gehrchen
BDBenny Dahl
Benny Dahl
Aims: Only a few studies have investigated the long-term health-related quality of life (HRQoL) in patients with an idiopathic scoliosis. The aim of this study was to investigate the overall HRQoL and employment status of patients with an idiopathic scoliosis 40 years after diagnosis, to compare it with that of the normal population, and to identify possible predictors for a better long-term HRQoL. Methods: We reviewed the full medical records and radiological reports of patients referred to our hospital with a scoliosis of childhood between April 1972 and April 1982. Of 129 eligible patients with a juvenile or adolescent idiopathic scoliosis, 91 took part in the study (71%). They were evaluated with full-spine radiographs and HRQoL questionnaires and compared with normative data. We compared the HRQoL between observation (n = 27), bracing (n = 46), and surgical treatment (n = 18), and between thoracic and thoracolumbar/lumbar (TL/L) curves. Results: The mean time to follow-up was 40.8 years (SD 2.6) and the mean age of patients was 54.0 years (SD 2.7). Of the 91 patients, 86 were female (95%) and 51 had a main thoracic curve (53%). We found a significantly lower HRQoL measured on all the Scoliosis Research Society 22r instrument (SRS-22r) subdomains (p < 0.001) with the exception of mental health, than in an age-matched normal population. Incapacity to work was more prevalent in scoliosis patients (21%) than in the normal population (11%). The median SRS-22r subscore was 4.0 (interquartile range (IQR) 3.3 to 4.4) for TL/L curves and 4.1 (IQR 3.8 to 4.4) for thoracic curves (p = 0.300). We found a significantly lower self-image score for braced (median 3.6 (IQR 3.0 to 4.0)) and surgically treated patients (median 3.6 (IQR 3.2 to 4.3)) than for those treated by observation (median 4.0 (IQR 4.1 to 4.8); p = 0.010), but no statistically significant differences were found for the remaining subdomains. Conclusion: In this long-term follow-up study, we found a significantly decreased HRQoL and capacity to work in patients with an idiopathic scoliosis 40 years after diagnosis. Cite this article: Bone Joint J 2023;105-B(2):166–171.

30 June 2019 in Neurospine
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SFSidsel Fruergaard
Sidsel Fruergaard
SOSøren Ohrt-Nissen
Søren Ohrt-Nissen
BDBenny Dahl
Benny Dahl
NKNicolai Kaltoft
Nicolai Kaltoft
MGMartin Gehrchen
Martin Gehrchen
Magnetic resonance imaging (MRI)-verified neural axis abnormalities (NAAs) have been described in adolescent idiopathic scoliosis (AIS), and several risk factors have been associated with the presence of NAAs in AIS patients. However, the clinical significance of these findings is unclear. The purpose of the present study was to determine the prevalence of NAAs in a large consecutive cohort of AIS patients and to evaluate the clinical significance of previously proposed risk factors. We prospectively included AIS patients referred to a tertiary facility for evaluation. Full-spine MRI scans were performed on all included patients irrespective of curve magnitude or proposed treatment modality. MRI scans were prospectively analyzed by a neuroradiologist and the pathologic findings were confirmed by a second independent radiologist. NAA was observed in 34 of the 381 patients (8.9%): 32 patients had a syrinx, 1 patient had an arachnoid cyst, and 1 patient had a Chiari malformation. Four patients were referred for a neurosurgical evaluation but none received any neurosurgical treatment. No statistically significant difference was observed between the NAA and non-NAA groups in terms of sex, major curve size, thoracic kyphosis, left thoracic curve, curve convexity, curve progression, or level of pain (p>0.05). In this prospective study examining the risk factors for NAA in AIS patients, we found that previously proposed risk factors could not predict the MRI outcomes. The finding of an NAA had no clinical implications and we do not support MRI scans as a routine diagnostic modality in all AIS patients.

10 October 2014 in BMC Anesthesiology
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KNKamilla Nielsen
Kamilla Nielsen
PJPär Ingemar Johansson
Pär Ingemar Johansson
BDBenny Dahl
Benny Dahl
MWMichael Wagner
Michael Wagner
BFBritt Frausing
Britt Frausing
LRLars S Rasmussen
Lars S Rasmussen
Transfusion with red blood cells (RBC) may be needed during hip revision surgery but the appropriate haemoglobin concentration (Hb) threshold for transfusion has not been well established. We hypothesized that a higher transfusion threshold would improve ambulation after hip revision surgery. The trial was registered at Clinicaltrials.gov ( NCT00906295 ). Sixty-six patients aged 18 years or older undergoing hip revision surgery were randomized to receive RBC at a Hb threshold of either 7.3 g/dL (restrictive group) or 8.9 g/dL (liberal group). Postoperative ambulation was assessed using Timed Up and Go-test (TUG) and ability to walk was also assessed daily by a physiotherapist blinded to the allocation. Fifty-three patients were able to perform the TUG and included in the analysis. The TUG could be completed in a median of 36 sec vs. 30 sec in the restrictive group and the liberal group, respectively (P = 0.02). The mean difference in TUG was 14.5 sec (95% CI 2.8-26.2 sec). No difference was found in the day patients could perform TUG or walk 10 meters. The Hb at the day of testing was 10.2 g/dL in the restrictive group and 9.9 g/dL in the liberal group. Only 26 patients received RBC. A Hb transfusion threshold of 8.9 g/dL was associated with a statistically significantly faster TUG after hip revision surgery compared to a threshold of 7.3 g/dL but the clinical importance is questionable and the groups did not differ in Hb at the time of testing.

1 May 2017 in Journal of Orthopaedic Surgery
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Journal Article
Open access
CDCasper Dragsted
Casper Dragsted
TATheis Aagaard
Theis Aagaard
SOSøren Ohrt-Nissen
Søren Ohrt-Nissen
MGMartin Gehrchen
Martin Gehrchen
BDBenny Dahl
Benny Dahl
To assess mortality, disability, and health-related quality of life (HRQL) in patients surgically treated for spondylodiscitis. A retrospective longitudinal study was conducted on all patients surgically treated for spondylodiscitis over a 6-year period at a single tertiary spine center. Indications for surgery, pre- and postoperative neurological impairment, comorbidities, and mortality were recorded. A survey was conducted on all eligible patients with the EuroQol 5-dimension (EQ-5D) questionnaire and Oswestry Disability Index (ODI). Sixty-five patients were diagnosed with spondylodiscitis not related to recent spine surgery. One-year mortality rate was 6%. In all, 36% and 27% had pre- and postoperative neurological impairment, respectively, with only one patient experiencing deterioration postoperatively. At final follow-up (median 2 years), mean ODI was 31% (SD = 22) and mean EQ-5D time trade-off score was 0.639 (SD = 0.262); this was significantly lower than that in the normal population (p < 0.001). Patients with neurological impairment prior to index surgery had lower EQ-5D scores (p = 0.005) and higher ODI (p = 0.02) at final follow-up compared with patients without neurological impairment. Several years after surgery, patients surgically treated for spondylodiscitis have significantly lower HRQL and more disability than the background population. Neurological impairment prior to index surgery predicts adverse outcome in terms of disability and lower HRQL.

21 February 2017 in Scoliosis and Spinal Disorders
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SOSøren Ohrt-Nissen
Søren Ohrt-Nissen
Jason Pui Yin CheungJason Pui Yin Cheung
Jason Pui Yin Cheung
DHDennis Winge Hallager
Dennis Winge Hallager
MGMartin Gehrchen
Martin Gehrchen
KKKenny Kwan
Kenny Kwan
DSDino Samartzis
Dino Samartzis
Current surgical treatment for adolescent idiopathic scoliosis (AIS) involves correction in both the coronal and sagittal plane, and thorough assessment of these parameters is essential for evaluation of surgical results. However, various definitions of thoracic kyphosis (TK) have been proposed, and the intra- and inter-rater reproducibility of these measures has not been determined. As such, the purpose of the current study was to determine the intra- and inter-rater reproducibility of several TK measurements used in the assessment of AIS. Twenty patients (90% females) surgically treated for AIS with alternate-level pedicle screw fixation were included in the study. Three raters independently evaluated pre- and postoperative standing lateral plain radiographs. For each radiograph, several definitions of TK were measured as well as L1–S1 and nonfixed lumbar lordosis. All variables were measured twice 14 days apart, and a mixed effects model was used to determine the repeatability coefficient (RC), which is a measure of the agreement between repeated measurements. Also, the intra- and inter-rater intra-class correlation coefficient (ICC) was determined as a measure of reliability. Preoperative median Cobb angle was 58° (range 41°–86°), and median surgical curve correction was 68% (range 49–87%). Overall intra-rater RC was highest for T2–T12 and nonfixed TK (11°) and lowest for T4–T12 and T5–T12 (8°). Inter-rater RC was highest for T1–T12, T1-nonfixed, and nonfixed TK (13°) and lowest for T5–T12 (9°). Agreement varied substantially between pre- and postoperative radiographs. Inter-rater ICC was highest for T4–T12 (0.92; 95% CI 0.88–0.95) and T5–T12 (0.92; 95% CI 0.88–0.95) and lowest for T1-nonfixed (0.80; 95% CI 0.72–0.88). Considerable variation for all TK measurements was noted. Intra- and inter-rater reproducibility was best for T4–T12 and T5–T12. Future studies should consider adopting a relevant minimum difference as a limit for true change in TK.

1 September 2014 in Spine
Verified
Journal Article
Closed access
MWMiao Wang
Miao Wang
AJAnders Bonde Jensen
Anders Bonde Jensen
SMSøren Schmidt Morgen
Søren Schmidt Morgen
CWChun Sen Wu
Chun Sen Wu
MSMing Sun
Ming Sun
CBCody Eric Md Bünger
Cody Eric Md Bünger
Study Design. We conducted a retrospective cohort study of 151 patients with breast cancer spinal metastases. Objective. To investigate the influence of breast cancer subtypes on survival duration of patients with breast cancer spinal metastases, and to aid spine surgeons in selecting treatments on a more precise basis. Summary of Background Data. There is lack of knowledge about specific prognosis of patients with spinal metastases in various breast cancer subtypes. Estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (Her-2) status are the key factors in determining breast cancer subtypes and predicting patients' response to adjuvant treatments. Methods. Until August 2013, we retrieved 151 surgically treated patients with breast cancer spinal metastases and followed up all the patients for at least 2 years. Survival duration analysis and Cox proportional hazards regression model unadjusted and adjusted by age were used. Results. Patients with ER-negative (−) breast cancer had 11 months shorter median survival duration (10.6 vs. 21.5 mo) and 48% higher mortality risk (P = 0.03) than those with ER-positive (+) breast cancer. Patients with PgR (−) status had 59% higher mortality risk than those with PgR (+) status (P = 0.02). Hormone receptor (HR) status is a combination of ER and PgR status. Patients with HR (−) status had an 11-month shorter median survival duration and 52% higher mortality risk (P = 0.01) than patients with HR (+) status. Human epidermal growth factor receptor 2 subtypes had similar median survival duration and mortality risk. Patients with triple-negative breast cancer had a median survival duration of only 9.9 months. Conclusion. Patients with spinal metastases with ER/HR (−) status and triple-negative breast cancer could be downgraded from score “5” to “3” in Tokuhashi scoring system and from “slow growth” to “moderate growth” in Tomita scoring system. Spine surgeons should be critical before performing high-risk extensive surgery in patients with ER/HR (−) status, and especially, in those with triple-negative status. Level of Evidence: 3