https://shura.shu.ac.uk/7180/1/Rodriggues_%2D_optical_techniques_%2D_Review_MIA_revision_v9.pdf

Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery.

Terahertz biophotonics as a tool for studies of dielectric and spectral properties of biological tissues and liquids

The contrast mechanism of medical endoscopy is mainly based on metrics of optical intensity and wavelength. As another fundamental property of light, polarization can not only reveal tissue scattering and absorption information from a different perspective, but can also provide insight into directional tissue birefringence properties to monitor pathological changes in collagen and elastin. Here we demonstrate a low cost wide field high definition Mueller polarimetric endoscope with minimal alterations to a rigid endoscope. We show that this novel endoscopic imaging modality is able to provide a number of image contrast mechanisms besides traditional unpolarized radiation intensity, including linear depolarization, circular depolarization, cross-polarization, directional birefringence and dichroism. This enhances tissue features of interest, and additionally reveals tissue micro-structure and composition, which is of central importance for tissue diagnosis and image guidance for surgery. The potential applications of the Mueller polarimetric endoscope include wide field early epithelial cancer diagnosis, surgical margin detection and energy-based tissue fusion monitoring, and could further benefit a wide range of endoscopic investigations through intra-operative guidance.

/pdf/a-high-definition-mueller-polarimetric-endoscope-for-tissue-189htlchi0.pdf

A high definition Mueller polarimetric endoscope for tissue characterisation

Medical robots have evolved from autonomous systems to tele-operated platforms and mechanically-grounded, cooperatively-controlled robots. Whilst these approaches have seen both commercial and clinical success, uptake of these robots remains moderate because of their high cost, large physical footprint and long setup times. More recently, researchers have moved toward developing hand-held robots that are completely ungrounded and manipulated by surgeons in free space, in a similar manner to how conventional instruments are handled. These devices provide specific functions that assist the surgeon in accomplishing tasks that are otherwise challenging with manual manipulation. Hand-held robots have the advantages of being compact and easily integrated into the normal surgical workflow since there is typically little or no setup time. Hand-held devices can also have a significantly reduced cost to healthcare providers as they do not necessitate the complex, multi degree-of-freedom linkages that grounded robots require. However, the development of such devices is faced with many technical challenges, including miniaturization, cost and sterility, control stability, inertial and gravity compensation and robust instrument tracking. This review presents the emerging technical trends in hand-held medical robots and future development opportunities for promoting their wider clinical uptake.

Hand-Held Medical Robots

https://spiral.imperial.ac.uk/bitstream/10044/1/79234/5/1-s2.0-S1361841520300645-main.pdf

Surgical spectral imaging

BACKGROUND Although the potential benefits of 3-dimensional (3-D) vs 2-dimensional (2-D) and high-definition (HD) vs standard-definition (SD) endoscopic visualization have long been recognized in other surgical fields, such endoscopes are generally considered too large and bulky for use within the brain. The recent development of 3-D and HD neuroendoscopes may therefore herald improved depth perception, better appreciation of anatomic details, and improved overall surgical performance. OBJECTIVE To compare simultaneously the effectiveness of 3-D vs 2-D and HD vs SD neuroendoscopy. METHODS Ten novice neuroendoscopic surgeons were recruited from a university hospital. A preclinical randomized crossover study design was adopted to compare 3-D vs 2-D and HD vs SD neuroendoscopy. The primary outcomes were time to task completion and accuracy. The secondary outcomes were perceived task workload using the NASA (National Aeronautics and Space Administration) Task Load Index and subjective impressions of the endoscopes using a 5-point Likert scale. RESULTS Time to task completion was significantly shorter when using the 3-D vs the 2-D neuroendoscopy (P = .001), and accuracy of probe placement was significantly greater when using the HD vs the SD neuroendoscopy (P = .009). We found that 3-D endoscopy significantly improved perceived depth perception (P < .001), HD endoscopy significantly improved perceived image quality (P < .001), and both improved participants' overall impression (P < .001). CONCLUSION Three-dimensional neuroendoscopy and HD neuroendoscopy have differing but complementary effects on surgical performance, suggesting that neither alone can completely compensate for the lack of the other. There is therefore strong preclinical evidence to justify 3-D HD neuroendoscopy.

/pdf/comparative-effectiveness-of-3-dimensional-vs-2-dimensional-2574dkrl65.pdf

Comparative effectiveness of 3-dimensional vs 2-dimensional and high-definition vs standard-definition neuroendoscopy: a preclinical randomized crossover study.

Sequential multispectral imaging is an acquisition technique that involves collecting images of a target at different wavelengths, to compile a spectrum for each pixel In surgical applications it suffers from low illumination levels and motion artefacts A three-channel rigid endoscope system has been developed that allows simultaneous recording of stereoscopic and multispectral images Salient features on the tissue surface may be tracked during the acquisition in the stereo cameras and, using multiple camera triangulation techniques, this information used to align the multispectral images automatically even though the tissue or camera is moving This paper describes a detailed validation of the set-up in a controlled experiment before presenting the first in vivo use of the device in a porcine minimally invasive surgical procedure Multispectral images of the large bowel were acquired and used to extract the relative concentration of haemoglobin in the tissue despite motion due to breathing during the acquisition Using the stereoscopic information it was also possible to overlay the multispectral information on the reconstructed 3D surface This experiment demonstrates the ability of this system for measuring blood perfusion changes in the tissue during surgery and its potential use as a platform for other sequential imaging modalities

Multispectral image alignment using a three channel endoscope in vivo during minimally invasive surgery.

Intraoperative ultrasound overlay in robot-assisted partial nephrectomy: first clinical experience.

Local excision of rectal cancer with transanal endoscopic microsurgery has proved to be a viable alternative to conventional, more radical techniques, but the reduced sensory experience presents significant challenges for the surgeon. Accurate identification and complete removal of lesions and subsurface targets is currently a difficult task, often exacerbated by intraoperative tissue deformation. This work describes novel ultrasound calibration and effective visualisation methods designed to meet these requirements, relying solely on optical measurements and pattern tracking. Detailed quantitative phantom and porcine validation experiments confirm that the technique is both practical and an accurate means for assessing lesion thickness intraoperatively, leading directly to human clinical trials.

/pdf/intraoperative-ultrasound-guidance-for-transanal-endoscopic-3rvq3a9n2o.pdf

Intraoperative ultrasound guidance for transanal endoscopic microsurgery

Contrast-free autofluorescence (AF) of the parathyroid glands (PTGs) and thyroid tissue occurs in the near-infrared (NIR) spectrum on excitation by light in the upper range of the visible spectrum or lower NIR spectrum. In vivo, PTGs autofluoresce more brightly than thyroid (by a factor of 2-20 times) and appear as a bright spot against surrounding thyroid, muscle or fat on a processed image which is generated in real-time. NIR-AF of PTGs was first described in 2009 although NIR-AF had previously been used in several other clinical applications. Since then there has been a great amount of interest in the use of NIR-AF in thyroid and parathyroid surgery with over 25 published reports of the utilisation of both self-built and proprietary NIR-AF devices in neck endocrine surgery. All of these reports have confirmed the feasibility of NIR-AF intraoperatively and its ability to detect PTGs, although the reported accuracy varies from 90-100%. Reports of the effect of NIR-AF on relevant clinical endpoints i.e., post-operative hypoparathyroidism in thyroidectomy and persistent disease in parathyroidectomy are however scant. There has been one multicentre clinical trial of NIR-AF in thyroidectomy but this did not report clinical outcomes and two single-centre, non-randomised studies which did report post-operative hypoparathyroidism but with differing results: one showing no benefit in 106 NIR-AF vs. 163 controls and one, a reduction of early hypocalcaemia from 20% to 5% in 93 NIR-AF patients vs. 420 controls. There were only 2 cases of permanent hypoparathyroidism across both studies and therefore no significant observable difference in this key outcome variable. In parathyroidectomy, possible variability of the AF signal due to composition of a PTG adenoma, secondary/tertiary disease and MEN1 as well as depth-penetration preventing detection of sub-surface PTGs would imply that NIR-AF in its current form is not well-placed to improve cure-rates in hyperparathyroidism, which may already be as high as 98%. Thus far, no study has addressed this. Despite the promising results of NIR-AF, the absence of data demonstrating an improvement in outcomes and the cost of its use currently limit its use in routine clinical practice, especially in a publicly funded healthcare system with budgetary constraints. However, it can be utilised in research settings and this should be undertaken within the context of well-designed and conducted randomised, multi-centre, appropriately powered studies, which will assist in establishing its role in neck endocrine surgery.

/pdf/near-infrared-autofluorescence-in-thyroid-and-parathyroid-1hejcqa32c.pdf

Aimee Di Marco

Papers

Comparative effectiveness of 3-dimensional vs 2-dimensional and high-definition vs standard-definition neuroendoscopy: a preclinical randomized crossover study.

Multispectral image alignment using a three channel endoscope in vivo during minimally invasive surgery.

Intraoperative ultrasound overlay in robot-assisted partial nephrectomy: first clinical experience.

Intraoperative ultrasound guidance for transanal endoscopic microsurgery

Near-infrared autofluorescence in thyroid and parathyroid surgery.