Sequence of mixed ophthalmic operating lists: A national survey of UK consultants.

Ophthalmic surgical operating lists include intraocular and extraocular procedures, as well as clean non-infectious and dirty infectious cases. Patient age, diabetic status, local or general anaesthesia must be considered during ophthalmic theatre scheduling. Traditionally children and 'clean cases' are prioritised. However, factors such as the need for an interpreter, patient transport and latex allergy affect the sequencing of ophthalmic lists. An electronic survey was sent to all UK ophthalmology consultants through the Royal College of Ophthalmologists registry, enquiring about their preference in sequencing mixed theatre lists, what operations they considered clean and dirty, and the presence of departmental protocol for list sequencing. There was a 16.9% response rate (n = 222/1311). A majority of 75.2% (n = 167/222) had mixed operating lists of intraocular and extraocular cases. Of those performing mixed operating lists, 44.3% (n = 74/167) stated they would operate on intraocular cases before extraocular cases, and 92.8% (n = 155/167) would perform 'clean' before 'dirty' cases. Fifty-nine per cent (n = 98/167) have a departmental protocol to help determine list order. This survey has demonstrated that there is a trend to perform 'clean' before 'dirty' and intraocular before extraocular cases. Given the results of the survey, we outline our recommendation on how to sequence mixed ophthalmic theatre lists.

Considerations for using Natalizumab treatment in patients with a history of choroidal melanoma.

Natalizumab is a monoclonal antibody licensed for the treatment of relapsing-remitting multiple sclerosis (RRMS). It is known to increase the potential risk of developing progressive multifocal leukoencephalopathy (PML). There is current debate in the literature regarding its association with malignant melanoma. Herein, we report a case of a 55-year old lady with RRMS for whom natalizumab therapy was being considered by her neurologist. Her medical history included a choroidal melanoma which had undergone successful treatment. Additionally, in this case study we discuss the issues regarding malignant melanoma risk and recurrence with natalizumab treatment.

EphB3: an endogenous mediator of adult axonal plasticity and regrowth after CNS injury.

Endogenous mechanisms underlying the remodeling of neuronal circuitry after mammalian CNS injury or disease remain primarily unknown. Here, we investigated axonal plasticity after optic nerve injury and found that macrophages recruited into the injury site and adult retinal ganglion cell (RGC) axons, which undergo injury-induced sprouting and terminal remodeling, were linked by their respective expression of a ligand and receptor pair active in axon guidance. Recruited macrophages specifically upregulated mRNA encoding the guidance molecule EphB3 and expressed EphB proteins capable of binding Ephrin B molecules in vivo and in vitro. Injured adult RGC axons in turn expressed EphrinB3, a known receptor for EphB3, and RGC axons bound recombinant EphB3 protein injected into the optic nerve. In vitro, EphB3 supported adult RGC axon outgrowth, and axons turned toward a source of this guidance molecule. In vivo, both reduction of EphB3 function in adult heterozygous animals and loss of function in homozygous animals greatly decreased RGC axon re-extension or sprouting after optic nerve injury. Comparisons of axon re-extension in EphB3 null and wild-type littermates showed that this loss of axonal plasticity was not attributable to a difference in intrinsic axon growth potential. Rather, the results indicated an essential role for local optic nerve-derived EphB3 in regulating adult RGC axon plasticity after optic nerve injury. Of note, the loss of EphB3 did not affect the ability of injured RGC axons to elaborate complex terminal branching, suggesting that additional EphB3-independent mechanisms governed adult axon branching triggered by CNS damage.

A randomized, fellow eye, comparison of keratometry, aberrometry, tear film, axial length and the anterior chamber depth after eye rubbing in non-keratoconic eyes.

BACKGROUND: To investigate the effect of eye rubbing on keratometry (K), aberrometry, tear film break-up-time (TFBUT) and anterior chamber depth (ACD). METHODS: Volunteers without any corneal pathology or dry eyes were randomised to rubbing in one eye and the fellow-eye was control. Eye rubbing was performed for 2 min. Primary outcomes studied were anterior and posterior K changes. Secondary outcomes were changes in TFBUT, axial length (AL) & ACD, K changes in various zones, asphericity and aberrometry. Pre and post rubbing K, aberrometry, ACD and TFBUT were assessed in a predetermined sequence. The relationship of the above parameters to axial length (AL) was also assessed. Astigmatism was analysed using vector analysis. RESULTS: Pre versus post rubbing, anterior flatter K further flattened (42.51 ± 1.52 D vs. 42.36 ± 1.53 D, p = 0.003) and the changes to J0 vector in central cornea (-0.16 ± 0.26 D vs. -0.27 ± 0.33 D, p = 0.038) suggested change to against-the-rule (ATR) astigmatism. There was significant change in Z2+2 polynomial following rubbing. We found a positive correlation between axial length and change in posterior K (r = 0.335, p = 0.020). The TFBUT reduced following eye rubbing (15.3 s vs. 13.9 s, p = 0.0001). There was a positive correlation between AL and increase in ACD post rubbing (r = 0.300, p = 0.038). There was a positive correlation between ACD and change in mean posterior K (r = 0.305, p = 0.035). CONCLUSIONS: In healthy eyes, following eye rubbing, there is a significant change in TFBUT and central anterior K changes towards ATR astigmatism. Longer eyes had more changes in posterior K and ACD. Whereas, eyes with deeper ACD showed more steepness of posterior K. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02131740.

Axon repair: surgical application at a subcellular scale.

Injury to the nervous system is a common occurrence after trauma. Severe cases of injury exact a tremendous personal cost and place a significant healthcare burden on society. Unlike some tissues in the body that exhibit self healing, nerve cells that are injured, particularly those in the brain and spinal cord, are incapable of regenerating circuits by themselves to restore neurological function. In recent years, researchers have begun to explore whether micro/nanoscale tools and materials can be used to address this major challenge in neuromedicine. Efforts in this area have proceeded along two lines. One is the development of new nanoscale tissue scaffold materials to act as conduits and stimulate axon regeneration. The other is the use of novel cellular-scale surgical micro/nanodevices designed to perform surgical microsplicing and the functional repair of severed axons. We discuss results generated by these two approaches and hurdles confronting both strategies.

In vivo use of a nanoknife for axon microsurgery.

OBJECTIVE: Microfabricated devices with nanoscale features have been proposed as new microinstrumentation for cellular and subcellular surgical procedures, but their effectiveness in vivo has yet to be demonstrated. In this study, we examined the in vivo use of 10 to 100 microm-long nanoknives with cutting edges of 20 nm in radius of curvature during peripheral nerve surgery. METHODS: Peripheral nerves from anesthetized mice were isolated on a rudimentary microplatform with stimulation microelectrodes, and the nanoknives were positioned by a standard micromanipulator. The surgical field was viewed through a research microscope system with brightfield and fluorescence capabilities. RESULTS: Using this assembly, the nanoknife effectively made small, 50 to 100 microm-long incisions in nerve tissue in vivo. This microfabricated device was also robust enough to make repeated incisions to progressively pare down the nerve as documented visually and by the accompanying incremental diminution of evoked motor responses recorded from target muscle. Furthermore, this nanoknife also enabled the surgeon to perform procedures at an unprecedented small scale such as the cutting and isolation of a small segment from a single constituent axon in a peripheral nerve in vivo. Lastly, the nanoknife material (silicon nitride) did not elicit any acute neurotoxicity as evidenced by the robust growth of axons and neurons on this material in vitro. CONCLUSION: Together, these demonstrations support the concept that microdevices deployed in a neurosurgical environment in vivo can enable novel procedures at an unprecedented small scale. These devices are potentially the vanguard of a new family of microscale instrumentation that can extend surgical procedures down to the cellular scale and beyond.

Microscale surgery on single axons.

OBJECTIVE: The lack of meaningful axon regeneration after central nervous system damage and poor functional recovery after serious peripheral nervous system nerve injuries have been long-standing problems of substantial interest to both neurosurgeons and neurobiologists. As an alternative to strategies that seek to promote the regeneration of adult axons, our research group has taken advantage of advances in microtechnology to develop a paradigm of direct axon repair involving the substitution of damaged axon regions with healthy segments from donor axons. METHODS: This repair methodology uses a novel combination of microtechnology, electrokinetic axon manipulation, and the well-established biological principle of cell fusion. These three fields of research have been integrated in a multidisciplinary approach to develop a solution for a significant clinical problem that currently has no specific treatment. RESULTS: The findings reported here provide some initial proof of principle for the core technologies we intend to use for axon repair. Functional recovery from nerve damage of course is clinically challenging, and many obstacles would need to be overcome before such axon repair procedures can be contemplated for therapeutic use. We identify some of the clinical issues that must be addressed for microtechnology-assisted axon repair to transition from the realm of research into actual surgical settings. CONCLUSION: It is hoped that each advance in axon repair technology will spur additional research to provide us with a comprehensive understanding on how best to pursue neurosurgical intervention at the microscale.