RDRobert N. Dunn

Robert N. Dunn

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Robert N. Dunn has a total of 135 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Digital PCR detection of Mycobacterium tuberculosis and HIV-1 co-localization in spinal tuberculosis biopsies

    by Robyn Waters, Adrian R Martineau, Maritz Laubscher, Robert N Dunn, Michael Held, Melissa-Rose Abrahams, Anna K Coussens

    Background: Mycobacterium tuberculosis ( Mtb ) and HIV-1 co-infection in tissues is suggested to favour reciprocal replication, infection and reservoir expansion. Yet, confirmation of this detrimental synergism in diseased tissues is limited. Methods: In this prospective study of 25 adults investigated for spinal tuberculosis (STB) in South Africa (13 (52%) people living with HIV-1 (PLWH), on antiretroviral treatment) 25 open surgery or CT-guided biopsies were collected and portioned into 93 segments. Extracted DNA was analysed by droplet digital PCR (ddPCR) to detect and quantify Mtb complex (MTBC) ( rpoB , IS6110 ), HIV-1 ( pol , gag ) and Human ( RPP30 ) gene copies. ddPCR sensitivity for Mtb was validated against Xpert-Ultra and culture. Total biopsy and intra-biopsy variation in pathogen DNA abundance, co-detection, and relationships to human cellularity, HIV status, and peripheral viral load (VL) evaluated. Results: ddPCR detected MTBC DNA in biopsies from 10/10 (100%) culture-confirmed STB, 5/6 (83%) Xpert Ultra-confirmed STB and 4/9 (44%) diagnosed Not STB (all 4 with previous pulmonary TB). Detected MTBC ranged from 8-59,144 rpoB copies/biopsy. RpoB copies/million human cells were higher in biopsies from PLWH (p=0.0096) and positively correlated with matched-segment HIV-1 pol copies/million cells (r=0.40; p=0.0003), but not VL. HIV-1 DNA was detected in all PLWH biopsies, four with undetectable VL. HIV-1 pol copies/million cells were higher in segments with MTBC DNA co-detected (p=0.011) and also correlated with VL (r=0.91; p=0.0003). Conclusions: Reciprocal relationships exists between Mtb and HIV-1 abundance in spinal tissue. Findings support investigating TB-HIV co-infected tissue segments to characterise how the immune microenvironment impacts HIV-1/ Mtb reservoir persistence and/or expansion.

  • Open Access

    Predictors of Early Mortality After Traumatic Spinal Cord Injury in South Africa

    by Alina Jacob, Christian R. Wirtz, Markus Loibl, Stefan Kruger, Benjamin H. Blankson, Robert N. Dunn, Nicholas A. Kruger

    Study Design: Retrospective cohort study. Objectives: To identify predictors for early mortality following traumatic spinal cord injury (TSCI), as recognition of factors associated with early mortality is essential for public resource allocation and optimized acute care. Methods: Retrospective Analysis of SCI patients admitted to the acute SCI ward from 2003 to 2022 was performed. Days elapsing from the date of injury to date of death established the survival time. Early mortality was defined as survival time ≤ 365 days. Multivariable logistic regression was used in modeling of early death following TSCI with age, gender, neurologic deficit, type of neurologic injury, ventilation status, and count of complications as covariates. Results: Simple logistic regression indicated a significant association of early mortality with the number of complications ( P < .0001), neurological deficit ( P < .0001), complete neurological injury ( P < .0001), ventilation status ( P < .0001), and age group ( P < .0003). After adjusting for other covariates, complete neurological injury (OR: 1.75, P < .0001), ventilation (OR: 2.80, P < .0001), and Age group (over 60 OR: 17.71, P < .0001) were significantly associated with early mortality. The multivariable model showed a good overall fit (Hosmer-Lemeshow P = .315; AUC 0.85). Conclusions: Predictors of early mortality after TSCI are high complete spinal cord injury, age, number of complications, and the need for ventilation. Identification of high-risk patients is crucial to rationalize and improve acute care to potentially reduce mortality rates.


  • Open Access

    Adolescent idiopathic scoliosis: shoulder balance and SRS-22 patient-reported outcome

    by Lubabalo Noconjo, Moses M Kimani, Robert N Dunn

    Background This is a retrospective database review with the objective to review adolescent idiopathic scoliosis (AIS) surgery in terms of radiographic and patient-reported surgical outcome, assessing the relationship with shoulder balance. Methods Database search identified 97 AIS patients who underwent single-stage corrective fusion between 2011 and 2017, and had one year follow-up. The average age at surgery was 15.0 (10.9-20.7 ± 2.1) years. Preoperative and one-year radiographic analysis included Cobb angles, flexibility and correction indices. The curves were classified according to Lenke as 43 type 1, 14 type 2, 11 type 3, 12 type 4, 12 type 5 and five type 6. Shoulder balance was assessed by T1 tilt angle, clavicle angle and shoulder height. Pre-and postoperative Scoliosis Research Society (SRS)-22 patient-reported outcome measures (PROMs) were assessed in relation to the radiographic results. Results In Lenke 1-4, the preoperative Cobb angle was 64.4° (26-99 ± 15.69), with a flexibility index of 28% corrected to 22.8° (6-62 ± 11.4). Lenke 5-6 thoracolumbar (TL) was corrected from 56.8° (30-88 ± 143), with a flexibility index of 46% to 12.7° (0-34 ± 7.9). Overall SRS-22 postoperative satisfaction was high at 9.6 (6-10 ± 0.9), with improvement in self-image and mental health domains. While preoperative T1 tilt angle was associated, clavicle angle and shoulder height showed no difference in SRS-22 score. Conclusion Surgery improved SRS-22 PROMs overall, as well as self-image and mental health domains. Radiographic shoulder imbalance did not negatively affect the PROM.


  • Open Access

    Current concepts: approach to spondylolysis

    by Robert N Dunn

    Lumbar spondylolysis is an acquired defect of the pars interarticular process ('isthmus') due to the human species' erect posture. Anatomical and load factors play a role. With lumbar extension, the superior vertebra's inferior articular process drives down dorsally on the inferior pars, causing a ventral tensile stress, bone oedema, fracture, and ultimately nonunion in some. The population incidence is around 6%, where most are inconsequential as they are asymptomatic and have a favourable natural history. In the physically highly active group, especially athletes, back and radicular pain is more common, leading to a three to four times higher incidence of lysis in this group. Although X-rays are typically the first imaging modality used, computed tomography (CT) is far more sensitive and, with staging, more predictive of fusion with comparable radiation dose. Magnetic resonance imaging (MRI) allows identification of bone oedema, a precursor of fracture, and assessment of the disc status. This has replaced previously used isotope bone scans and single-photon emission computed tomography (SPECT). Management involves cessation of physical activity and bracing to block extension for three to six months, with around 90% resolution of symptoms. Union rate is negatively related to bilaterality and terminal stage (nonunion), but not necessarily correlated to symptom/functional status. Surgical intervention in those that fail nonoperative care includes pars repair or fusion, with a high fusion and return to activity rate. The young athlete poses a particular challenge due to return to play pressure, but still does well with nonoperative care and subsequent activity modification. Counselling of the family and sports staff is extremely important when planning treatment in this high-demand group. Level of evidence: Level 5

  • Open Access

    Private healthcare sector spine surgery: patient and surgeon profiles from a large open medical scheme in South Africa

    by T Mann, I Vlok, R N Dunn, S Miseer, J Davis

    Background It is generally understood that the profile of spine surgery varies by setting, based on factors such as the age profile of the population, the economic context and access to healthcare. Relatively little is known about the profile of spine surgery in South Africa, although one previous report from the public healthcare sector suggested a high burden of trauma and infection-related surgery. To our knowledge, there has been no formal investigation in the private sector. A holistic understanding of spine surgery within our setting may be beneficial for applications such as resource allocation and informing the training needs of future specialists. Objectives To provide insight into spinal surgery in the South African private healthcare sector by describing spine surgery characteristics within a large open medical scheme, including both patient and surgeon profiles. Methods This retrospective review included adult inpatient spine surgeries funded by the largest open medical scheme in South Africa between 2008 and 2017. An anonymized dataset extracted from the scheme records included patient demographics, ICD-10 codes, procedure codes and surgeon specialization. Descriptive patient and surgery data were presented. Furthermore, the association between patient and surgery factors and surgeon specialization was investigated using univariate and multivariate analyses. Results A total of 49,576 index spine surgeries were included. The largest proportion of surgeries involved members 40-59 years old (n=23,543, 48%), approximately half involved female members (n=25,293, 51%) and most were performed by neurosurgeons (n=35,439, 72%). At least 37,755 (76%) surgeries were for degenerative pathology, 2,100 (4%) for trauma and 242 (0.5%) for infection. Adjusted risk ratios (aRR) significantly associated with orthopaedic surgeon specialization included cervical spine region aRR = 0.49 (95% C.I. 0.39-0.61), trauma aRR = 1.50 (95% C.I. 1.20-1.88), deformity aRR = 1.77 (95% C.I. 1.33-2.35) and blood transfusion aRR = 1.46 (95% C.I. 1.12-1.91). Conclusion Spine surgery in South Africa’s largest open medical scheme was dominated by surgery for degenerative pathology in older adults and was performed largely by neurosurgeons. This constituted a stark contrast to a previous report from the public sector and highlighted a mismatch between exposure during public sector registrar training and private practice post-specialization. The findings support the need for private-public collaboration as well as the importance of spine fellowships for all specialists intending to practice spine surgery.


  • Open Access

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

    by T. N. Mann, R. N. Dunn, A. J. Vlok, J. H. Davis

    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.


  • Open Access

    Orthopaedic surgical training exposure at a South African academic hospital - is the experience diverse and in depth?

    by Cara Dunn, Michael Held, Maritz Laubscher, Marc Nortje, Stephen Roche, Robert Dunn

    BACKGROUND: With increasing pressure on our training hospitals, we undertook to ascertain whether our clinical orthopaedic surgery training platform is providing adequate surgical exposure, both in diversity and the level of trainee participation METHODS: The orthopaedic surgery database was interrogated for theatre procedures logged for the 12-month period 1 January to 31 December 2018. Each theatre case was assessed as to the level of trainee participation, whether it was performed during or after hours, and categorised as being elective or trauma in nature, as well as the orthopaedic subdiscipline RESULTS: A total of 3 147 orthopaedic surgical procedures were logged with an even split of elective (51.1%) and trauma (49.9%) cases. Adults predominated in the trauma group while the paediatric service contributed most to the elective cases, followed by arthroplasty and spine. Overall, 25.5% of procedures were performed by consultants and 74.5% by registrars. Registrars were more frequently the primary surgeon in trauma cases (90%) compared to elective procedures (59%) (p < 0.001). Of the elective cases, 37% were performed by registrars as supervised unscrubbed and 22% as supervised scrubbed operations. In total, 17.5% of cases were performed after hours, with 31.7% of trauma surgeries and only 2.9% of elective surgeries occurring after hours. Registrars were the primary surgeon in 98.7% of after-hours trauma cases and 58% of after-hours elective cases under unscrubbed supervision CONCLUSION: Our study presents the surgical experience and level of participation available to orthopaedic surgical trainees in a South African training hospital where their exposure was an equal number of elective and trauma cases. The vast majority of the cases were performed by the registrars in their supervised unscrubbed capacity although the more complex, elective cases were performed by consultants. Almost all after-hours trauma cases were performed by registrars. This suggests the platform allows for a high level of registrar surgical participation and training despite the challenges. Further review is required to assess achievement of trainee competency and whether in fact the current experience is adequate Level of evidence: Level 4 Keywords: orthopaedic registrar surgical experience, South African orthopaedic training exposure, orthopaedic case exposure

  • Proximal junctional kyphosis post tuberculous spine corrective surgery in paediatric patients

    by Sandile Mkize, Robert Dunn

    Study design Retrospective case series. Summary of background data Proximal junctional kyphosis (PJK) is a well-recognised post-operative complication of deformity correction surgery. Our local tuberculosis (TB) endemic is responsible for severe kyphotic deformities. The most challenging is in the paediatric environment where powerful instrumentation is used in immature spines with more flexible disco-ligamentous structures than adults. Objective To establish the incidence of PJK and management thereof in our paediatric TB spine patients undergoing corrective surgery. Methods Twenty-seven consecutive paediatric patients undergoing fusion surgery for TB spine with 2-year follow-up were identified from our prospectively maintained database. Age at surgery was 8.0 years (2.5–17 ± 3.98) with 14 under the age of 7. Only anterior surgery was performed in 1, posterior only in 13 and combined in 13 with a total of 5 (1–11) levels fused. Results Nine (33.3%) patients developed PJK (progression by > = 10°) with an average progression of 16.2°(11–26 ± 5.42) compared the overall cohorts change of 5.1°(− 26–15 ± 9.24). Although not reaching statistical significance, there was a trend to higher incidence of PJK when instrumented, 8/20 (40%) compared to 1/7 (14.3%), more so in posterior only surgery compared to combined, 6/13 (46.2%) compared to 3/13 (23.1%) and when the UIV was at T7 or above, 7/17 (41.2%) compared to 2/10 (20%). There was a higher PJK rate when the number of levels fused was > = 6, 7/12 (58.3%) compared to 2/10 (p = 0.014), when the kyphotic correction was more than 39º, 5/8 (62.5%) compared to 4/19 (21.1%) (p = 0.07) and when < = 7 years old, 7/14 (50%) compared to 2/13 (15.4%) (p = 0.05). Two of the nine PJK cases required revision for junctional failure. Conclusion In paediatric TB kyphosis correction, there was a 33% incidence of PJK with 2/9 requiring revision surgery for proximal failure. Our data suggest that this incidence of PJK was related to the magnitude of correction, the number of levels fused with a trend of increase in higher UIVs, posterior approach and instrumentation.This suggests that in young children, one should be cautious of overzealous kyphosis correction due to the risk of catastrophic proximal junctional failure.


  • Topics, Skills, and Cases for an Undergraduate Musculoskeletal Curriculum in Southern Africa

    by Michael F.G. Held, Maritz Laubscher, Simon M. Graham, Nicholas Kruger, Phinda Njisane, Vela Njisane, Robert N. Dunn, on behalf of the Learning Innovation via Orthopaedic Networks (LION) Group

    Background: Most patients with orthopaedic pathology in low to middle-income countries are treated by nonspecialists. A curriculum to prepare undergraduate medical students for this duty should reflect the local pathology and skills that are required to manage patients in a resource-restricted environment. The aim of this study was to establish and prioritize a list of core orthopaedic-related knowledge topics, clinical cases, and skills that are relevant to medical students in southern Africa and areas with a similar clinical context. Methods: A modified Delphi consensus study was conducted with 3 interactive iterative rounds of communication and prioritization of items by experts from Africa, Europe, and North America. Preferred priorities were selected but were limited to 50% of all of the possible items. Percent agreement of ≥75% was defined as consensus on each of these items. Results: Most of the 43 experts who participated were orthopaedic surgeons from 7 different countries in southern Africa, but 28% were general practitioners or doctors working in primary or secondary-level facilities. Experts prioritized cases such as patients with multiple injuries, a limping child, and orthopaedic emergencies. Prioritized skills were manipulation and immobilization of dislocations and fractures. The most important knowledge topics included orthopaedic infections, the treatment of common fractures and dislocations, any red flags alerting to specialist referral, and back pain. Surgical skills for the treatment of urgent care conditions were included by some experts who saw a specific need in their clinical practice, but these were ranked lower. Conclusions: A wide geographic, academic, and expertise-specific footprint of experts informed this international consensus through their various clinical and academic circumstances. Knowledge topics, skills, and cases concerning orthopaedic trauma and infection were prioritized by the highest percent agreement. Acute primary care for fractures and dislocations ranked high. Furthermore, the diagnosis and the treatment of conditions not requiring specialist referral were prioritized. This study can inform national curricula in southern Africa and assist in the allocation of student clinical rotations.


  • Infographic: Impact of HIV on spontaneous spondylodiscitis

    by R. N. Dunn, S. Castelein, M. Held

    The British Editorial Society of Bone & Joint Surgery