Silver-impregnated, antibiotic-impregnated or non-impregnated ventriculoperitoneal shunts to prevent shunt infection: the BASICS three-arm RCT

BACKGROUND

Insertion of a ventriculoperitoneal shunt to treat hydrocephalus is one of the most common neurosurgical procedures worldwide. Shunt infection affects up to 15% of patients, resulting in long hospital stays, multiple surgeries and reduced cognition and quality of life.

OBJECTIVES

The aim of this trial was to determine whether or not antibiotic-impregnated ventriculoperitoneal shunts (hereafter referred to as antibiotic shunts) (e.g. impregnated with rifampicin and clindamycin) or silver-impregnated ventriculoperitoneal shunts (hereafter referred to as silver shunts) reduce infection compared with standard ventriculoperitoneal shunts (hereafter referred to as standard shunts).

DESIGN

This was a three-arm, superiority, multicentre, parallel-group randomised controlled trial. Patients and a central primary outcome review panel, but not surgeons or operating staff, were blinded to the type of ventriculoperitoneal shunt inserted.

SETTING

The trial was set in 21 neurosurgical wards across the UK and the Republic of Ireland.

PARTICIPANTS

Participants were patients with hydrocephalus of any aetiology who were undergoing insertion of their first ventriculoperitoneal shunt.

INTERVENTIONS

Participants were allocated 1 : 1 : 1 by pressure-sealed envelope to receive a standard non-impregnated, silver-impregnated or antibiotic-impregnated ventriculoperitoneal shunt at the time of insertion. Ventriculoperitoneal shunts are medical devices, and were used in accordance with the manufacturer's instructions for their intended purpose.

MAIN OUTCOME MEASURES

The primary outcome was time to ventriculoperitoneal shunt failure due to infection. Secondary outcomes were time to failure for any cause, reason for failure (infection, mechanical), types of ventriculoperitoneal shunt infection, rate of infection after first clean (non-infected) revision and health economics. Outcomes were analysed by intention to treat.

RESULTS

Between 26 June 2013 and 9 October 2017, 1605 patients from neonate to 91 years of age were randomised to the trial: n = 36 to the standard shunt, n = 538 to the antibiotic shunt and n = 531 to the silver shunt. Patients who did not receive a ventriculoperitoneal shunt (n = 4) or who had an infection at the time of insertion (n = 7) were not assessed for the primary outcome. Infection occurred in 6.0% (n = 32/533) of those who received the standard shunt, in 2.2% (n = 12/535) of those who received the antibiotic shunt and in 5.9% (n = 31/526) of those who received the silver shunt. Compared with the standard shunt, antibiotic shunts were associated with a lower rate of infection (cause-specific hazard ratio 0.38, 97.5% confidence interval 0.18 to 0.80) and a decreased probability of infection (subdistribution hazard ratio 0.38, 97.5% confidence interval 0.18 to 0.80). Silver shunts were not associated with a lower rate of infection than standard shunts (cause-specific hazard ratio 0.99, 97.5% confidence interval 0.56 to 1.74). The ventriculoperitoneal shunt failure rate attributable to any cause was 25.0% overall and did not differ between arms. Antibiotic shunts save £135,753 per infection avoided. There were no serious adverse events.

LIMITATIONS

It was not possible to blind treating neurosurgeons to the ventriculoperitoneal shunt type. The return rate for patient-reported outcomes was low. Limitations to the economic evaluation included failure to obtain Hospital Episode Statistics data from NHS Digital, as per protocol. Reliance on patient-level information and costing systems data mitigated these limitations.

CONCLUSIONS

Antibiotic shunts have a reduced infection rate compared with standard shunts, whereas silver shunts do not. Antibiotic shunts are cost-saving.

FUTURE WORK

A sample collection has been established that will enable the study of surrogate markers of ventriculoperitoneal shunt infection in cerebrospinal fluid or blood using molecular techniques. A post hoc analysis to study factors related to shunt failure will be performed as part of a future study. An impact analysis to assess change in practice is planned.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN49474281.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 17. See the NIHR Journals Library website for further project information.

Comparative study between sodium carboxymethyl-cellulose silver, moist exposed burn ointment, and saline-soaked dressing for treatment of facial burns

Facial burns vary from relatively minor insults to severe debilitating injuries. Sustaining a burn injury is often a psychological trauma for the victim and is especially menacing when the face and neck are involved. This study was carried out on 60 patients with superficial dermal burns to the face admitted to the Burn Unit of Tanta University Hospital, Egypt, from September 2007 to July 2008. The patients were allocated randomly to one of three groups, each of which was treated with one of the following: sodium carboxymethyl-cellulose silver (Aquacel Ag®), MEBO® (moist exposed burn ointment), or saline-soaked dressing. We found that patients managed with MEBO® had less pain and itching and easier movement than those managed with Aquacel Ag®, while the Aquacel Ag® group required a shorter duration of time for healing, without any bad odour, than the MEBO® group. Quality of healing and patient satisfaction were nearly equal as regards MEBO® and Aquacel Ag®. Saline-soaked dressings were least satisfactory - they caused the most pain and itching, limited the patients' movements the most, needed the longest time for healing, and gave patients the least satisfaction. It was concluded that MEBO® was an excellent choice for management of facial burns owing to its soothing effect, ease of patient movement, easy handling, and good healing properties. Aquacel Ag® was found to be comparable to MEBO® and is specially recommended when frequent dressings cause difficulties for the patients or when they cannot accept a bad odour; saline-soaked dressings are not recommended for the management of facial burns because of the pain they cause, itching, limitation of patient movement, and delayed healing.

A Comparative Study of the Wound Healing Properties of Moist Exposed Burn Ointment (MEBO) and Silver Sulphadiazine

Burns expose the deeper tissues of the skin or body to invasive microbes. Topical preparations for treating burn wounds, to be useful, should ideally have antibiotic power and promote healing. Silver compounds have been the mainstay of topical burn treatment for decades. However, most chemical substances retard wound healing. Several natural agents such as honey and moist exposed burn ointment (MEBO) are believed to protect wounds from infection and promote healing without causing any of the adverse effects of purified chemicals. In this study, we compared the wound healing properties of MEBO, a herbal preparation of Chinese origin, with silver sulphadiazine (SSD), a long-standing conventional burn dressing. Ten adult Sprague Dawley rats were divided into two groups. They were housed in separate cages and received partial-thickness burn wounds on their dorsal skin. They were then treated with MEBO and SSD. The wounds were inspected daily until day 8, when all the animals were sacrificed, perfused with normal saline, and had their wounds excised and prepared for histology. It was found that animals in both groups were well preserved. No clinical infections occurred. Wound healing was at an advanced stage by day 8 in all the animals. Clinical and histological examination showed that the two agents gave the animals comparable protection and healing possibilities. It is concluded that MEBO is a suitable and efficacious alternative to conventional silver-based topical therapies for treating partial-thickness burn wounds.

Management of the Acute Partial-thickness Burned Hand; Moist Exposed Burn Ointment or Silver Sulphadiazine Cream both Combined with a Polyethylene Bag

Hand burns predominantly affect young adults, and therefore have serious social and financial implications. In the present work, 106 patients with less than 25% body surface area burns and acute partial-thickness burned hands were managed using polyethylene bags and 1% local silver sulphadiazine (SSD) cream or moist exposed burn ointment (MEBO). Females made up 61.3% of the cases and flame burn was the majority cause (54.7%). There were no significant differences between the two groups regarding either the analgesic effect after local ointment application or hand movement inside the polyethylene bag. Local agent crustation over the wound was very evident in the hands managed by local 1% SSD cream (69.81%). On follow-up, the burned hands healed faster using local MEBO (10.48 versus 14.53 days), with fewer post-burn hand deformities and better active hand movements; however, the total cost until complete hand burn wound healing was higher with MEBO than with 1% SSD, although the final results were superior, with early return to work, when MEBO was used. We concluded that the use of MEBO as a topical agent and of polyethylene bags for the dressing of the acute partial-thickness burned hand accelerated healing; daily wound evaluation was easy as there was no crustation over it of the agent. It was more expensive than 1% SSD cream but presented fewer post-burn complications and more rapid healing, with shorter hospital stay.

Histochemical investigations of a silver method for axons

Silver ion is not specific either in location or in action in the present silver method. Studies with radioactive silver, with the dark-field microscope, and with simple reducing solutions demonstrate a general distribution of silver ion in the impregnated tissue. Copper and mercury may be substituted for silver in the impregnating solution. A water-soluble aldehyde is necessary as a fixative. The substrate for staining appears to require the presence of protein-bound amine groups. The product-forming solution does not require the presence of a reducing agent. Sulfite ion is not necessary. All controllable sources of base that were utilized produced the histologic results. The product appears to be silver oxide in terms of the present solubility studies.

Platinized silver chloride electrode

A hybrid electrode made by platinizing silver-silver chloride has been found to combine the stable potential and low direct-current resistance properties of a silver-silver chloride electrode with the low high-frequency impedance characteristic of a platinized platinum electrode.

ENZYMIC CONVERSION OF 3-HYDROXYANTHRANILIC ACID INTO CINNABARINIC ACID BY THE NUCLEAR FRACTION OF RAT LIVER

1. An enzyme solely localized in the nuclear fraction of rat liver was found to convert 3-hydroxyanthranilic acid into a red product that was isolated and crystallized from the reaction mixture. The product was identified as cinnabarinic acid (2-amino-3-oxo-3H-phenoxazine-1,9-dicarboxylic acid) by comparing its properties with synthetic cinnabarinic acid. 2. The enzyme had optimum pH at 7.2. Heavy-metal ions like Ag(+), Hg(2+), MoO(4) (2-), Fe(2+) and Cu(2+) were inhibitory; Mn(2+) activated the reaction to a considerable extent. 3. The reaction was inhibited by mercaptoethanol, GSH and cysteine, and activated by p-hydroxymercuribenzoate and sodium arsenite, which may suggest the involvement of disulphide groups in the reaction.

REACTION OF THE CARCINOGEN DIMETHYLNITROSAMINE WITH PROTEINS AND WITH THIOL COMPOUNDS IN THE INTACT ANIMAL

1. [(14)C]Dimethylnitrosamine was administered to rats, and the formation of free and protein-bound S-methylcysteine was investigated. 2. Very little S-methylcysteine was found in liver acid-soluble fraction, in liver protein or in urine. 3. The methylhistidines formed in liver protein were found to have largely disappeared by 6 days after injection of dimethylnitrosamine. 4. The significance of these results in the carcinogenic action of dimethylnitrosamine is discussed.