Organ curvature sensing using pneumatically attachable flexible rails in robotic-assisted laparoscopic surgery

In robotic-assisted partial nephrectomy, surgeons remove a part of a kidney often due to the presence of a mass. A drop-in ultrasound probe paired to a surgical robot is deployed to execute multiple swipes over the kidney surface to localise the mass and define the margins of resection. This sub-task is challenging and must be performed by a highly-skilled surgeon. Automating this sub-task may reduce cognitive load for the surgeon and improve patient outcomes. The eventual goal of this work is to autonomously move the ultrasound probe on the surface of the kidney taking advantage of the use of the Pneumatically Attachable Flexible (PAF) rail system, a soft robotic device used for organ scanning and repositioning. First, we integrate a shape-sensing optical fibre into the PAF rail system to evaluate the curvature of target organs in robotic-assisted laparoscopic surgery. Then, we investigate the impact of the PAF rail's material stiffness on the curvature sensing accuracy, considering that soft targets are present in the surgical field. We found overall curvature sensing accuracy to be between 1.44% and 7.27% over the range of curvatures present in adult kidneys. Finally, we use shape sensing to plan the trajectory of the da Vinci surgical robot paired with a drop-in ultrasound probe and autonomously generate an Ultrasound scan of a kidney phantom.

Antimicrobial photodynamic active biomaterials for periodontal regeneration

OBJECTIVE

Biomaterials for periodontal regeneration may have insufficient mechanical and antimicrobial properties or are difficult to apply under clinical conditions. The aim of the present study was to develop a polymeric bone grafting material of suitable physical appearance and antimicrobial photodynamic activity.

METHODS

Two light curable biomaterials based on urethane dimethacrylate (BioM1) and a tri-armed oligoester-urethane methacrylate (BioM2) that additionally contained a mixture of β-tricalcium phosphate microparticles and 20wt% photosensitizer mTHPC (PS) were fabricated and analyzed by their compressive strength, flexural strength and modulus of elasticity. Cytotoxicity was observed by incubating eluates and in direct-contact to MC3T3-E1 cells. Antimicrobial activity was ascertained on Porphyromonas gingivalis and Enterococcus faecalis upon illumination with laser light (652nm, 1×100J/cm², 2×100J/cm²).

RESULTS

The compressive strength, flexural strength and elastic modulus were, respectively, 311.73MPa, 22.81MPa and 318.85MPa for BioM1+PS and 742.37MPa, 7.58MPa and 406.23MPa for BioM2+PS. Both materials did not show any cytotoxic behavior. Single laser-illumination (652nm) caused total suppression of P. gingivalis (BioM2+PS), while repeated irradiation reduced E. faecalis by 3.7 (BioM1+PS) and 3.1 (BioM2+PS) log-counts.

SIGNIFICANCE

Both materials show excellent mechanical and cytocompatible properties. In addition, irradiation with 652nm induced significant bacterial suppression. The manufactured biomaterials might enable a more efficient cure of periodontal bone lesions. Due to the mechanical properties functional stability might be increased. Further, the materials are antimicrobial upon illumination with light that enables a trans-mucosal eradication of residual pathogens.

Endorsing single-unit transfusion combined with a restrictive haemoglobin transfusion threshold after knee arthroplasty

PROBLEM

The utility of single-unit transfusions in the presence of restrictive haemoglobin transfusion thresholds is unknown.

DESIGN

A prospective, pre-post intervention study was undertaken to evaluate a new transfusion strategy designed to reduce the rate of allogeneic transfusion and promote single-unit transfusion.

SETTING

Joint replacement centre within a public hospital.

PARTICIPANTS

Patients undergoing primary unilateral knee arthroplasty (baseline, n=93; postintervention, n=347). OBJECTIVES OF THE INTERVENTION: Decrease the use of donor blood by (1) reducing the rate of donor transfusion and (2) endorsing the use of single-unit transfusion.

STRATEGIES FOR CHANGE

A restrictive transfusion protocol was introduced, which included assessment of the need for transfusion based on haemoglobin value, and presence of signs, symptoms and comorbidity. Single or multiple units of blood were endorsed depending on the indication.

KEY MEASURES FOR IMPROVEMENT

Primary outcomes were transfusion rate; frequencies of attempted and successful single-unit transfusions. Secondary outcomes included 6-week haemoglobin and complications within 6 months postsurgery.

EFFECTS OF CHANGE

Transfusion rate significantly improved (41% (38/93) to 18% (64/347), chi(2) 21.3, p<0.001). The prescription of single units of blood (24% (9/38) to 33% (21/64), chi(2) 1, p=0.33) and successful single-unit transfusion (24% (9/38) vs 24% (15/64), chi(2)<0.01, p=1.0) were unchanged as were most secondary outcomes.

LESSONS LEARNT

Restrictive haemoglobin thresholds are a safe, potent frontline strategy for decreasing the rate of blood transfusion. Judicious endorsement of single units is a secondary strategy for reducing the consumption of donor blood when the transfusion haemoglobin trigger is strict.

Growth hormone therapy in Silver Russell syndrome: 5 years experience of the Australian and New Zealand Growth database (OZGROW)

Data were analysed on 33 children (22 males) with Silver Russell syndrome treated with growth hormone for periods up to 5 years. Baseline data (medians) at commencement of growth hormone (GH) therapy were age 6.7 years, bone age delay 1.7 years, height standard deviation score (SDS)-3.2, weight SDS -3.1, and growth velocity 5.7 cm/ year. All were prepubertal. Median birth weight SDS for gestational age was -3.2. GH was commenced at 14 IU/m2 per week and subsequently adjusted according to response. Growth velocity and growth velocity SDS for chronological age (CA) improved over baseline and gains in height SDS for CA were 1.0, 1.5 and 1.8 SD over 3, 4 and 5 years respectively (P < 0.001). No significant increase in height SDS for bone age was observed. Increased GH doses were required after the 1st year to maintain growth rates. Mean bone age advancement was 3.1 years after 3 years of treatment, and 6.0 years after 5 years treatment. Younger age was a predictor of the growth response over the 1st year. Predictors of response after 3 years were catch up growth, low weight SDS at birth and low height SDS for CA. Age at onset of puberty was normal, but height at onset of puberty was lower than normal means.

CONCLUSION

We have demonstrated significant improvement in growth in Silver Russell syndrome after 3 years of GH therapy, however data on estimated mature height and final height are insufficient to conclude final outcomes. Further follow up is required to assess the long-term benefit.

Growth hormone therapy for 3 years: the OZGROW experience

OBJECTIVE

To examine the growth response over 3 years of growth hormone deficient (GHD) and non-GHD children who have received growth hormone (GH) in Australia.

METHODOLOGY

A retrospective study of a group of patients (1362 children) who commenced GH prior to 1 September 1990. Data were collected at 12 growth centres located in major cities throughout Australia. The data were transferred after informed consent to the national OZGROW database located at the Royal Alexandra Hospital for Children, Sydney, NSW. Of the 1362 children, 898 had received 3 years or more GH therapy and were eligible for this analysis. This cohort was then categorized by diagnosis. Growth response was assessed using height standard deviation score, estimated mature height, growth velocity (GV), GH dose and bone age (years).

RESULTS

For children who completed 3 years therapy, the baseline characteristics among diagnostic groups were similar with mean height standard deviation score (SDS) less than -3 SDS (except for the malignancy group) and mean GV ranging from 3.5 to 4.4cm/year. The GV during the first year improved in all groups (7.7-9.4cm/year)followed by an attenuated response during the second and third years of therapy. After 3 years GH therapy the GHD group with peak levels <10 mU/L demonstrated the greatest change in estimated mature height and height SDS. The GHD group with peak levels between > or = 10 but <2OmU/L had a growth response similar to the non-GHD children for all outcome parameters. Change in bone age ranged from 3.1 to 3.8 years with no differences being noted between the diagnostic groups, nor consistently with pubertal status.

CONCLUSIONS

Australian GH guidelines have targeted very short children when compared to other series. This large cohort of non-GHD children has demonstrated short-term benefits of GH therapy; however, the long-term benefit remains unclear until these children reach final adult height.

Adverse events during growth hormone therapy

The aim of this study was to ascertain the frequency of adverse events occuring during GH therapy in Australia and New Zealand since 1988. Data for children receiving GH has been collected prospectively on a national database, OZGROW, after informed consent has been given. Adverse events were coded by clinicians and have been analysed in relation to the nature of the event and the underlying diagnosis. There were 2922 subjects analysed, representing 9004 years of GH therapy. 151 subjects reported a total of 210 adverse events giving an overall frequency of 2.3% adverse events/patient treated year. Events that were probably related to GH therapy included peripheral oedema, injection site problems and increased frequency of kyphoscoliosis and slipped epiphysis in some groups. Adverse events were more frequent in growth hormone deficient children who had previously been treated for leukaemia, 8.1%, and in children previously treated for craniopharyngioma, 5.6%. A lower frequency was found for those with a diagnosis of idiopathic short stature, 1.6%, and familial short stature, 0.9%. Kyphoscoliosis was more frequently seen in Turner's syndrome, and slipped epiphyses in adolescent individuals with growth hormone deficiency, especially following treatment for leukaemia. There were no de novo tumours reported but the frequencies of recurrence/patient year for leukaemia, solid cranial tumours and craniopharyngioma were 1.1%, 2.2% and 3.8% respectively. A low frequency of adverse events has been reported on the OZGROW database but subsets of patients may be at increased risk of musculoskeletal abnormalities during GH therapy. The frequency of tumour recurrence during therapy is not different from known rates of recurrence in individuals not treated with GH.