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Title: An investigation of surgical pathways utilising femtosecond laser technology to increase the efficiency and safety of cataract surgery within a public health sector setting
Author: Roberts, Harry William
ISNI:       0000 0004 7970 1079
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2019
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The femtosecond laser (FL) has been introduced into cataract surgery within the last 10 years and continues to provoke much interest, with strong opinions on either side of the debate concerning its value; both potential and real. It offers automation and precision for several steps of cataract surgery but at a significant financial cost. Many case series and cohort studies have been published in the academic literature, but there are only a few randomised controlled trials comparing FL assisted cataract surgery (FLACS) with the gold standard of conventional phacoemulsification cataract surgery (CPS), and these are generally underpowered. Some National Health Service (NHS) hospitals are adopting this technology but at significant financial cost and there is yet a lack of convincing evidence for any clinical benefit of this technology. The aim of this MD(Res) project was to investigate whether FLACS technology can offer clinical benefit or with differing models of service delivery provide costeffectiveness to public sector cataract services. The primary hypothesis was whether a FL incorporated into a 'hub-and-spoke' pathway (whereby one FL treats patients and feeds them into multiple operating theatres) would improve productivity, and whether these productivity gains are sufficient to offset the additional costs associated with the technology itself. In order to address these questions this thesis comprises six studies: 1. To fully understand the running of NHS cataract theatre lists, time-motion studies (TMS) were conducted at cataract theatre lists in 5 different institutions (four NHS hospitals, one private hospital). Individual tasks, and their timings, of every member of staff were recorded. This study represents the first published TMS of cataract surgery and showed significant variability in the number of cases performed and the efficiency of patient flow between different institutions. Hypotheses were made as to factors supporting or hindering productivity, including staffing levels in individual surgical theatres and individual task allocation. 2. A hypothetical financial model was designed to compare FLACS with CPS for the provision of cataract surgery within the NHS. This study highlighted the significance of the cost of the disposable patient interfaces (PI) over the capital cost of the femtosecond laser itself. It concluded that there would need to be a significant improvement in productivity offered by FLACS over CPS, as well as significant discounting from the manufacturers of the PI, to offset the associated costs associated with this technology. 3. To evaluate the learning curve of the first 288 consecutive FLACS operations among 3 surgeons of differing grades of experience, who were naïve to the FLACS procedure. Surgical outcomes were analysed using a risk-adjusted cumulative sum method (CUSUM) to estimate the length of the learning curve for each surgeon, with regards to all complications and specifically posterior capsular rupture (PCR). The results of the pooled suggest stability in the rate of PCR after the first 16 cases. 4. A randomised controlled trial (RCT) was conducted to compare FLACS with CPS in 400 eyes of 400 consecutive patients. The analysis of the results found no statistically significant differences between the treatment arms in unaided or corrected visual acuity, refractive outcomes, phacoemulsification energy, endothelial cell loss, macular oedema, or patient reported outcome measures. The only statistically significant difference found was in the rates of posterior capsular rupture (FLACS 0%, CPS 3% p=0.03). 5. Surgeries within the RCT, described above, were performed within a high-volume surgery model. The FLACS arm was performed within a 2:1 hub and spoke model, while the CPS arm was performed with 2 theatres operating in parallel. This is the only study to date to evaluate the productivity of FLACS within a hub and spoke setting. FLACS with a hub-and-spoke model was significantly faster than CPS, with patients spending less time in theatre. This enabled a slight improvement in productivity, but not sufficient to meaningfully offset the additional costs relating to FLACS. 6. A sub-analysis of the FLACS RCT was undertaken to compare the effectiveness of manual limbal relaxing incisions (LRI) with femtosecond laser arcuate keratotomies (FS-AK) in the management of corneal astigmatism at the time of cataract surgery. All patients with corneal astigmatism greater than 0.9 dioptres (D) were offered treatment with either LRI (n=51) or FS-AK (n=53). Visual acuity, post-operative refraction, and corneal topography were recorded as well as any surgical complications. Analysis was performed according to the Alpins method. The FS-AK group had a significantly lower difference vector and higher correction index than the LRI group. 44% of patients treated with FS-AK attained a postoperative astigmatism of < 0.5D compared with 20% in the LRI group.
Supervisor: Hammond, Christopher John Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available