Effect of 3-Dimensional Virtual Reality Models for Surgical Planning of Robotic-Assisted Partial Nephrectomy on Surgical Outcomes: A Randomized Clinical Trial

IMPORTANCE

Planning complex operations such as robotic-assisted partial nephrectomy requires surgeons to review 2-dimensional computed tomography or magnetic resonance images to understand 3-dimensional (3-D), patient-specific anatomy.

OBJECTIVE

To determine surgical outcomes for robotic-assisted partial nephrectomy when surgeons reviewed 3-D virtual reality (VR) models during operative planning.

DESIGN, SETTING, AND PARTICIPANTS

A single-blind randomized clinical trial was performed. Ninety-two patients undergoing robotic-assisted partial nephrectomy performed by 1 of 11 surgeons at 6 large teaching hospitals were prospectively enrolled and randomized. Enrollment and data collection occurred from October 2017 through December 2018, and data analysis was performed from December 2018 through March 2019.

INTERVENTIONS

Patients were assigned to either a control group undergoing usual preoperative planning with computed tomography and/or magnetic resonance imaging only or an intervention group where imaging was supplemented with a 3-D VR model. This model was viewed on the surgeon's smartphone in regular 3-D format and in VR using a VR headset.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was operative time. It was hypothesized that the operations performed using the 3-D VR models would have shorter operative time than those performed without the models. Secondary outcomes included clamp time, estimated blood loss, and length of hospital stay.

RESULTS

Ninety-two patients (58 men [63%]) with a mean (SD) age of 60.9 (11.6) years were analyzed. The analysis included 48 patients randomized to the control group and 44 randomized to the intervention group. When controlling for case complexity and other covariates, patients whose surgical planning involved 3-D VR models showed differences in operative time (odds ratio [OR], 1.00; 95% CI, 0.37-2.70; estimated OR, 2.47), estimated blood loss (OR, 1.98; 95% CI, 1.04-3.78; estimated OR, 4.56), clamp time (OR, 1.60; 95% CI, 0.79-3.23; estimated OR, 11.22), and length of hospital stay (OR, 2.86; 95% CI, 1.59-5.14; estimated OR, 5.43). Estimated ORs were calculated using the parameter estimates from the generalized estimating equation model. Referent group values for each covariate and the corresponding nephrometry score were summed across the covariates and nephrometry score, and the sum was exponentiated to obtain the OR. A mean of the estimated OR weighted by sample size for each nephrometry score strata was then calculated.

CONCLUSIONS AND RELEVANCE

This large, randomized clinical trial demonstrated that patients whose surgical planning involved 3-D VR models had reduced operative time, estimated blood loss, clamp time, and length of hospital stay.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers (1 registration per site): NCT03334344, NCT03421418, NCT03534206, NCT03542565, NCT03556943, and NCT03666104.

Lack of TAR-DNA binding protein-43 (TDP-43) pathology in human prion diseases

AIMS

TAR-DNA binding protein-43 (TDP-43) is the major ubiquitinated protein in the aggregates in frontotemporal dementia with ubiquitin-positive, tau-negative inclusions and motor neurone disease. Abnormal TDP-43 immunoreactivity has also been described in Alzheimer's disease, Lewy body diseases and Guam parkinsonism-dementia complex. We therefore aimed to determine whether there is TDP-43 pathology in human prion diseases, which are characterised by variable deposition of prion protein (PrP) aggregates in the brain as amyloid plaques or more diffuse deposits.

MATERIAL AND METHODS

TDP-43, ubiquitin and PrP were analysed by immunohistochemistry and double-labelling immunofluorescence, in sporadic, acquired and inherited forms of human prion disease.

RESULTS

Most PrP plaques contained ubiquitin, while synaptic PrP deposits were not associated with ubiquitin. No abnormal TDP-43 inclusions were identified in any type of prion disease case, and TDP-43 did not co-localize with ubiquitin-positive PrP plaques or with diffuse PrP aggregates.

CONCLUSIONS

These data do not support a role for TDP-43 in prion disease pathogenesis and argue that TDP-43 inclusions define a distinct group of neurodegenerative disorders.

Inherited prion disease with 5-OPRI: phenotype modification by repeat length and codon 129

BACKGROUND

Human prion diseases have sporadic, acquired and inherited etiologies and show considerable phenotypic heterogeneity. An individual inherited prion disease offers an opportunity to study the determinants of this clinicopathologic heterogeneity among individuals with the same causal mutation.

METHODS

We report clinical and pathologic data from three families with different 5-octapeptide repeat insertion (5-OPRI) mutations of the prion protein gene (PRNP), extending the reported phenotypic range of this mutation.

RESULTS

The proband of a South African family presented with a rapidly progressive dementia and atypical pathology associated with kuru-like prion protein plaques. The original mutation in this family probably occurred on a PRNP allele encoding a 1-octapeptide repeat deletion polymorphism. This has not been previously reported as a precursor allele in over 30 other OPRI mutation kindreds. An English family with a genetically distinct mutation but identical protein product showed clinical onsets that varied 30 years between father and daughter, an effect that may be explained by their genotypes at PRNP codon 129. A patient from Northern Ireland with a phenotype of sporadic Creutzfeldt-Jakob disease presenting with visual disturbance was unexpectedly found to have a 5-OPRI.

CONCLUSIONS

When these cases were combined with the existing world literature, the mean age at onset for patients with 5-octapeptide repeat insertion (5-OPRI) was significantly later than that for patients with 6-OPRI, but both mutations exhibit a similar powerful disease modifying effect of PRNP codon 129.

Prion infectivity in variant Creutzfeldt-Jakob disease rectum

BACKGROUND

Disease-related prion protein (PrP(Sc)) is readily detectable in lymphoreticular tissues in variant Creutzfeldt-Jakob disease (vCJD), but not in other forms of human prion disease. This distinctive pathogenesis, with the unknown population prevalence of asymptomatic vCJD infection, has led to significant concerns that secondary transmission of vCJD prions will occur through a wide range of surgical procedures. To date PrP(Sc):prion infectivity ratios have not been determined in vCJD, and it is unknown whether vCJD prions are similar to experimental rodent prions, where PrP(Sc) concentration typically reflects infectious prion titre.

AIM

To investigate prion infectivity in vCJD tissue containing barely detectable levels of PrP(Sc).

METHODS

Transgenic mice expressing only human PrP (Tg(HuPrP129M(+/+)Prnp(o/o))-35 and Tg(HuPrP129M(+/+)Prnp(o/o))-45 mice) were inoculated with brain or rectal tissue from a previously characterised patient with vCJD. These tissues contain the maximum and minimum levels of detectable PrP(Sc) that have been observed in vCJD.

RESULTS

Efficient transmission of prion infection was observed in transgenic mice inoculated with vCJD rectal tissue containing PrP(Sc) at a concentration of 10(4.7)-fold lower than that in vCJD brain.

CONCLUSIONS

These data confirm the potential risks for secondary transmission of vCJD prions via gastrointestinal procedures and support the use of PrP(Sc) as a quantitative marker of prion infectivity in vCJD tissues.

Expression pattern of a mini human PrP gene promoter in transgenic mice

The prion protein is central to the pathogenesis of prion diseases, although its exact function remains unclear. Although transgenic mice have been widely utilised in prion research, their PrP expression patterns have not been characterised in detail. We have studied the developmental temporal and spatial expression of a 214-bp mini human PrP promoter in transgenic mice. Transgene expression is first detected at embryonic day 12.5, a day earlier than previously reported for endogenous mouse gene by in situ hybridization. The general expression pattern closely mirrors that of the endogenous mouse PrP gene, such that this small and clearly defined transgene cassette can replace the need to use large cosmid based vectors for transgenetic modeling of human and animal prion disease.

Expression of a peptide epitope of the colonic mucin MUC2 in precursor lesions to gastric carcinoma

Previous histochemical studies have shown that changes occur in the composition of mucins both in preneoplastic and neoplastic lesions of the gastric mucosa. Since monoclonal antibodies are now available which recognize the protein product of distinct mucin genes, they are likely to provide useful tools for evaluating these changes. Thus, a monoclonal antibody 996/1 raised against a peptide epitope of the colonic mucin MUC2 was examined for its potential as a prognostic indicator in gastric cancer. 996/1 works well on formalin-fixed paraffin sections and shows good staining of the colonic goblet cells in the region of the golgi, while there is no staining of normal control gastric mucosa. The epitope was detected in all cases of intestinal metaplasia (44 samples) and some but not all cases of dysplasia (26 samples) and gastric carcinoma (74 samples). There was no significant difference between the positivity of the tumours according to their classification, stage and lymph node status. These results unfortunately gave little indication that this antibody would be a useful prognostic tool in gastric cancer. However, the pattern of 996/1 staining provides useful information about the molecular changes in mucin expression that occur in gastric carcinogenesis.

p53 expression in Barrett's oesophagus, dysplasia, and adenocarcinoma using antibody DO-7

Barrett's oesophagus has a well-recognized association with oesophageal adenocarcinoma, with phenotypic progression through dysplasia to malignancy. The nuclear phosphoprotein p53 is a putative tumour suppressor with mutations resulting in both loss of negative growth regulatory function and possible gain of oncogene function. Many mutant forms have a prolonged half-life and are demonstrable with immunohistochemical techniques. We examined 62 endoscopic oesophageal biopsies and 36 oesophageal resections for p53 overexpression using the monoclonal antibody DO-7 on paraffin-embedded tissue. The series included 40 cases of Barrett's metaplasia, 13 cases of dysplasia, and 81 cases of adenocarcinoma. None of the cases of metaplasia was p53-positive, compared with 4/13 cases of dysplasia and 52/81 cases of adenocarcinoma. There was no association between the degree of dysplasia and p53 expression, although a trend emerged of increasing p53 expression with higher tumour grade. We conclude that p53 overexpression is frequent in oesophageal adenocarcinoma and may be related to tumour grade. p53 overexpression is not restricted to neoplastic lesions and mutation of this tumour suppressor may occur early in the malignant progression of Barrett's oesophagus.