Bimanual Dissection Research Articles

Vitrectomy for cases of diabetic retinopathy.

Microvascular complications of diabetic retinopathy (DR) may require surgical intervention in the form of vitrectomy. Since its inception, diabetic vitrectomy has evolved with introduction of better instruments, newer techniques, and smaller port sizes. Common indications for diabetic vitrectomy include nonresolving vitreous hemorrhage, tractional retinal detachment, epiretinal membrane, progression of fibrovascular membranes despite laser therapy, recalcitrant diabetic macular edema, and neovascular glaucoma. Preoperative systemic stabilization is essential prior to planning surgery. Surgical techniques commonly used in diabetic vitrectomy are segmentation, delamination, and rarely en-bloc dissection. Modification in surgical techniques such as chandelier-assisted bimanual dissection and pharmacological adjuvants improve surgical outcomes in these patients. Prognosis in these patients could be improved with early intervention. Studies evaluating the outcome of vitrectomy in patients with early proliferative DR are required to understand the appropriate time of intervention in patients. Treatment aimed at arresting the progression of DR and gene therapy are avenues that need further evaluation. The following review will focus on covering the epidemiology of DR, indications of vitrectomy, preoperative considerations, surgical procedures of diabetic vitrectomy, methods of membrane dissection, pharmacological adjuvants to vitrectomy, outcomes of diabetic vitrectomy, and future directions of diabetic vitrectomy.

Vitrectomy for diabetic retinopathy: A review of indications, techniques, outcomes, and complications

Abstract Diabetic retinopathy is one of the most severe forms of retinopathy and a leading cause of blindness all over the world. Of a greater concern is proliferative diabetic retinopathy which leads to vitreous haemorrhage and tractional retinal detachment in such cases. A majority of these cases require a surgical intervention to improve vision and prevent further vision loss. Surgical manouevers in these cases require a complex combination of vitrectomy, membrane dissection, judious usage of endodiathermy, endolaser, vital dyes, bimanual dissection and usage of intraoperative and post-operative tamponades. Each case presents a unique challenge and necessitates an appropriate combination of the steps mentioned above. In the current review we present the current understanding of the need for surgery in diabetic retinopathy, various surgical approaches and a summary of current literature on the same. Multiple surgical video clips demonstrating these steps are also included in this review.

Neuroendoscopy: The State of the Art

Over the past century, neuroendoscopy developed into a mainstay of neurosurgical practice, allowing for minimally invasive approaches to the ventricles, skull base, and spine. Its development, however, is far from over. Current challenges are inherent in the very feature that renders neuroendoscopy appealing-the small channels of the modern endoscope allow surgery to be performed with minimal tissue retraction, but they also make hemostasis and resection of large masses difficult. New optics allow for significantly improved image quality; yet open craniotomy often allows for 3-dimensional visualization and bimanual dissection and is part of everyday neurosurgical training. Finally, the utilization of neuroendoscopy remains limited, presenting ongoing challenges for neurosurgical teaching and achievement of technical mastery.

Training model for the fetal myelomeningocele correction with multiportal endoscopic technique.

The recent history of myelomeningocele has shown that treatment during the fetal life may reduce the risk of developing hydrocephalus in individuals by approximately 50%. Thus, a significant advancement involves fetal surgery performed through an endoscopic technique in which portals are placed to introduce the forceps and laparoscopic instruments. However, the development of this technique requires training; therefore, this study aimed to develop a training model for fetal myelomeningocele repair technique with multi-portal endoscopy. Two stages of endoscopic technique development were performed. The first stage consisted of exercises in order to familiarize the surgeon with 2D-vision endoscopic surgery, associated with the application of exercises focused on surgical skills, such as the development of laparoscopic knots in a synthetic model. The second stage involved the creation and application of the stages of myelomeningocele closure with a non-living animal model consisting of a chicken breast to simulate the myelomeningocele and a basketball to simulate the gravid uterus, in which perforations were made to introduce vascular introducers (portals) that, as in vivo, are used as portals (trocars) for the introduction of laparoscopic instruments. Overall, two different scenarios with three portals and two portals were tested. In three-portal simulator, the triangular apex trocar was used for the introduction of 4-mm 0° or 30° optics or even Minop type neurodoscope (Aesculap®, Germany) that was operated by the assistant surgeon; the other two portals are used for the introduction of laparoscopic instruments. Thus, the surgeon is able to perform maneuvers bimanually since dissection to laparoscopic sutures. In two-portal simulator, the surgeon and assistant stay side by side and one of the portals is used for the optic and the other for the laparoscopic instruments. There is no possibility of bimanual dissection in this method. Realistic simulation models for endoscopic fetal surgery for myelomeningocele correction are easily performed and help develop the necessary skills for fetal surgery teams.

Single-Position Anterior and Lateral Lumbar Fusion in the Supine Position: A Novel Technique for Multilevel Arthrodesis

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion are common techniques that typically require staged procedures when performed in combination. Interest is emerging in single-position surgery to increase operative efficiency. We report a novel surgical technique, supine extended reach lateral fusion, to perform ALIF and lateral lumbar interbody fusion with the patient in a single supine position. A man in his fifties presented with degenerative levoscoliosis, spondylolisthesis, sagittal plane deformity, and progressive low back pain. He was offered L3-S1 anterolateral fusion. With the patient supine, a left abdominal paramedian incision was performed to gain anterior retroperitoneal access, and standard L5-S1 and L4-5 ALIFs were performed. The anterior incision was used for direct visualization, retraction, and bimanual dissection. A left lateral incision was then made to perform an L3-4 lateral lumbar interbody fusion. He subsequently underwent a second-stage L3-S1 posterior percutaneous fixation. The patient tolerated the procedures well, without complications. His postoperative radiograph findings confirmed acceptable implant positioning. He was discharged home in stable condition and was doing well at follow-up. This case description is the first report of the supine extended reach technique, which allows incorporation of anterior and lateral fusion constructs at adjacent levels without changing patient positioning. Many surgeons believe the ALIF to be the most powerful technique for achieving lordosis, and this technique enables concomitant lateral access in a supine position. It can also be used as an alternative strategy when anterior access to the disc space is unobtainable. Further clinical investigation of this technique is warranted.

Анализ геморрагических осложнений в хирургии пролиферативной диабетической ретинопатии

Purpose. Determination of factors associated with the incidence of hemophthalmos in the early and late postoperative period in patients with proliferative diabetic retinopathy (PDR). Material and мethods. Retrospective analysis of postoperative complications was performed in 124 patients (133 eyes) with PDR, who received treatment at the Research institute of Eye Diseases from 2018 to 2021. The study included patients with PDR with indications for surgical treatment (hemophthalmos, traction retinal detachment (TRD), traction diabetic macular edema). All patients underwent minimally invasive vitrectomy using additional chandelier-type illuminators with bimanual dissection and delamination of the proliferative tissue and careful removal of the vitreous base with sclerocompression. In all cases, the operation was completed without the use of any tamponade. Peripheral retinal photocoagulation (RP) was performed in 98 cases (73.7 %), phacoemulsification with intraocular lens implantation in 66 cases (49.6 %), angiogenesis inhibitors were used perioperatively in 47 cases (35.3 %). Results. Of 133 operated eyes, early postoperative intravitreal hemorrhage (EPH) was observed in 17 cases (12.8 %), of which 6 resorbed spontaneously and 11 required repeated surgical intervention. The development of EPH was significantly associated with the absence of intraoperative RP (p < 0.01), and the frequency of revision of the vitreal cavity to eliminate EPH correlated with the unstable course of arterial hypertension (AH) (p= 0.048) and with the absence of panretinal photocoagulation (PRP) before surgery (p= 0.012). It was found that EPH developed more often in patients operated on for TRD (p= 0.007) and in cases accompanied by severe intraoperative bleeding (p= 0.001) and unintentional intraoperative damage to the retinal vessels of the 2nd-3rd order (p< 0.01). Late postoperative intravitreal hemorrhage (LPH) was observed in 20 cases (19.8 %), of which 11 resorbed spontaneously and 9 required surgical treatment. The development of LPH is significantly associated with the absence of intraoperative RP (p< 0.01 for self-resorbed LPH and p= 0.041 for LPH requiring revision of the vitreal cavity). The frequency of revision of the vitreal cavity for the treatment of LPH is significantly associated with the unstable course of hypertension (p= 0.007) and the presence of EPH requiring surgical intervention (p= 0.003). The use of anti-angiogenic drugs before and during surgery did not show a significant correlation with the occurrence of EPH and LPH. Conclusions. Analysis of complications showed that EPH and LPH occurred in 12.8 % and 19.8 % of cases, respectively. Factors associated with the development of EPH were identified: the absence of PRP before surgery, the absence of intraoperative RP, TRD, intraoperative damage to the retinal vessels of the 2nd-3rd order. Factors associated with the development of LPH were identified: failure to perform RP intraoperatively, unstable course of hypertension, and the presence of EPH that required surgical intervention. Keywords: diabetic retinopathy, vitrectomy, bianual vitrectomy, postoperative hemorrhage, panretinal photocoagulation, peripheral retinal photocoagulation, arterial hypertension.

Supine Lateral Lumbar Interbody Fusion: Cadaveric Proof of Principle for Simultaneous Anterior and Lateral Approaches

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly performed in separate stages with a change in patient positioning to provide arthrodesis in the lumbar spine. Interest has emerged in performing these approaches as a single-stage surgery with the patient in the lateral decubitus position. The objective of this study was to evaluate the technical feasibility of performing minimally invasive anterolateral fixation in a single supine position. Two fresh-frozen cadavers were used and placed supine. Standard minimally invasive anterior access was obtained by the approach surgeon. ALIF was performed at L5-S1 using standard techniques. A lateral incision was marked over the L4-5 disc space using fluoroscopy. Direct palpation and bimanual dissection were achieved through the same anterior incision, allowing access to the retroperitoneal space. Dilator and retractor docking was performed under fluoroscopic guidance. Direct visualization of the docking hardware through the anterior incision was used to ensure the safety of peritoneal contents and vasculature. LLIF was then performed using standard techniques at L4-5. Plain radiographs confirmed acceptable positioning of both ALIF and LLIF grafts. No injury to the cadaveric peritoneum, vasculature, or lumbar plexus was observed. A slightly enlarged anterior incision also permitted retroperitoneal access and visualization of the L3-4 disc space. This cadaveric feasibility study demonstrates that combined minimally invasive ALIF and LLIF may be performed as a single-stage procedure with the patient in the supine position. Clinical consideration and study of this approach are warranted.

Petrosal Approach for Giant Retrochiasmatic Craniopharyngioma: 2-Dimensional Operative Video.

Microsurgical resection of craniopharyngiomas poses significant challenges, which are amplified with tumors in the retrochiasmatic location and larger size. Traditional pterional trans-sylvian, subfrontal translamia terminalis, or interhemispheric approaches provide narrow surgical corridors with obstructed visualization of the tumor by the prefixed chiasm and slit optic carotid window.1-5 The superior extension of the tumor compressing the hypothalamus and third ventricle are likewise inaccessible. Dissection through these approaches requires crossing and manipulation of the already compromised optic apparatus with surgical instruments. Finally, the basilar artery and its perforating branches are often adherent to the posterior aspect of the tumor, and are invisible. Endonasal endoscopic techniques have been utilized as a surgical approach that accesses the tumor without crossing the optic apparatus; however, these approaches have a significant risk of cerebrospinal fluid leakage and require dissection of the basilar artery and hypothalamus from long distances with lengthy instruments.6-9 Frequently, the surgeon achieves only partial removal. The petrosal approach is ideal for tumors in the retrochiasmatic location.10-13 Advantages include unhindered access to the retrochiasmatic space without crossing the optic nerve and chiasm. The angle of approach allows visualization superiorly to the hypothalamus. Additionally, the approach shortens the distance to the tumor, allowing for delicate bimanual dissection of the tumor, especially at the basilar artery and hypothalamic interfaces. This video demonstrates three cases of retrochiasmatic craniopharyngioma resection through the petrosal approach, highlighting these advantages to optimize patient outcome. The patients and guardians consented for the surgery, photography, and publication of the patient's image. Figures from Al-Mefty et al11 used with permission from the Journal of Neurosurgery Publishing Group. Additional figures republished from Al-Mefty et al.12 "The petrosal approach for the resection of retrochiasmatic craniopharyngiomas," Neurosurgery, 2008, volume 62, issue 5 Suppl 2 (ONS), ONS331-ONS336, by permission of the Congress of Neurological Surgeons.

Endoscopic supracerebellar infratentorial approach to pineal and posterior third ventricle lesions in prone position with head extension: a technical note

ABSTRACT Objective The supracerebellar infratentorial (SCIT) approach is frequently used for the treatment of lesions in the pineal and posterior third ventricle region and can be performed in a sitting or prone position. We describe our experience with the purely endoscopic SCIT approach, using a prone position, with neck extension and head rotation. Methods We analysed all paediatric and adult patients operated on between July 2013 and January 2018 using the purely endoscopic SCIT approach. The surgical procedure was conducted through a paramedian subtorcular key-hole suboccipital craniotomy. The assistant held the endoscope and the surgeon used fine, long shaft instruments for bimanual tumour dissection. The prone position with head retroflexion allowed a gravity-aided enlargement of the anatomical surgical corridor between tentorium and cerebellum and enhanced venous blood drainage, similarly to the sitting or semi-sitting position, but with a decreased risk of air embolism. Results The approach allowed a complete removal of lesions located in the pineal region and in the posterior part of the third ventricle. Seven patients have been operated with this approach. All of them had the tumour completely removed. No permanent neurological deficits have been observed. Conclusions The endoscopic SCIT approach enables effective and safe removal of pineal and posterior third ventricle lesions, even of moderate dimensions (up to 3 cm). The endoscope guarantees a detailed view and illumination of the deep-seated structures. The tumour resection can be performed with bimanual use of microsurgical instruments.

Assessing the surgical outcome of the "chopsticks" technique in endoscopic transsphenoidal adenoma surgery.

The "chopsticks" technique is a 3-instrument, 2-hand mononostril technique that has been recently introduced in endoscopic neurosurgery. It allows a dynamic surgical view controlled by one surgeon only while keeping bimanual dissection. Being a mononostril approach, it requires manipulation of the mucosa of one nasal cavity only. The rationale of the technique is to reduce nasal morbidity without compromising surgical results and complication rates. There are, however, no data available on its results in endoscopic surgery (transsphenoidal surgery [TSS]) for pituitary adenoma. The authors performed a cohort analysis of prospectively collected data on 144 patients (156 operations) undergoing TSS using the chopsticks technique with 3T intraoperative MRI. All patients had at least 3 months of postoperative neurosurgical, endocrinological, and rhinological follow-up (Sino-Nasal Outcome Test-20 [SNOT-20] and Sniffin' Sticks). The surgical technique is described, and the achieved gross-total resection (GTR) and extent of resection (EOR) together with patients' clinical outcomes and complications are descriptively reported. On 3-month postoperative MRI, GTR was achieved in 71.2% of patients with a mean EOR of 96.7%. GTR was the surgical goal in 122 of 156 cases and was achieved in 106 of 122 (86.9%), with a mean EOR of 98.7% (median 100%, range 49%-100%). There was no surgical mortality. At a median follow-up of 15 months (range 3-70 months), there was 1 permanent neurological deficit. As of the last available follow-up, 11.5% of patients had a new pituitary single-axis deficit, whereas 26.3% had improvement in endocrinological function. Three patients had new postoperative hyposmia. One patient had severe impairment of sinonasal function (SNOT-20 score > 40). The operation resulted in endocrine remission in 81.1% of patients with secreting adenomas. This study shows that the chopsticks technique confers resection and morbidity results that compare favorably with literature reports of TSS. This technique permits a single surgeon to perform effective endoscopic bimanual dissection through a single nostril, reducing manipulation of healthy tissue and thereby possibly minimizing surgical morbidity.

Suction Spatula for Surgery of Vestibular Schwannomas in Supine Position: Technical Note

Resection of vestibular schwannomas with good functional outcome remains a neurosurgical challenge. In this study, we report on our initial experience with a suction spatula, which allows free bimanual dissection of small tumors in a clear, bloodless surgical field in supine position. Forty-one patients underwent vestibular schwannoma surgery in supine position, using a suction spatula. To analyze its feasibility, 11 aspects of the device were compared with the regular retractor. The suction spatula was successfully applied in all surgeries. Compared with a common spatula, the suction spatula showed superior performance during meatotomy, microsurgical and endoscopic tumor dissection, and management of bleedings. We noted no difference in ergonomics, compatibility, instrumental conflict, costs, reusability, and sterilization issues. Minor performance was related to its thickness/size. There were no significant disadvantages according to our data. There were no surgical complications related to this device. The main advantage of the suction spatula is in the treatment of small, mainly intrameatal vestibular schwannomas in supine patient position. It gives the surgeon a "third hand" while enabling a continuous bimanual dissection with 2 microinstruments without the use of a regular suction tip.

Evaluation of Retinal Detachment After Diabetic Vitrectomy: Causes and Ways of Management.

PurposeTo assess the causes and the ways of management of rhegmatogenous retinal detachment (RRD) after pars plana vitrectomy (PPV) performed in diabetic patients with advanced diabetic eye disease.MethodsRetrospective review of the records of the patients who had undergone PPV for complicated proliferative diabetic retinopathy (PDR) was done. Cases with RRD after the PPV were analyzed in the study (n = 32). Preoperative, operative, and postoperative data of the patients were recorded. All patients were recruited for a final follow-up visit.ResultsThis retrospective case-control study included 400 eyes of 345 patients. Prolonged surgical duration increased the risk of developing RRD (odds ratio = 1.6342, p = 0.0321). The presence of intraoperative retinal breaks increased the risk of developing postoperative RRD (odds ratio = 2.2308, p = 0.0380). Also, complex diabetic detachment that needed for bimanual dissection of the membranes during surgery were associated with a higher risk of developing postoperative RRD (odds ratio = 2.7311, p = 0.0401).ConclusionRhegmatogenous retinal detachment following diabetic vitrectomy needs a further vitrectomy for the management and usually has poor visual outcome. Prolonged surgical duration, the presence of intraoperative retinal breaks, and the need for bimanual dissection of the membranes (major complex cases) during surgery were associated with higher risk of developing RRD postoperatively.

Development of a Modular Cadaveric Endoscopic Orbital Surgery Model.

Introduction Endoscopic orbital surgery requires the acquisition of unique skill set including endoscopic bimanual dissection of intra/extraconal lesions adherent to orbital fat and neurovascular structures. Our goal was to develop a modular cadaveric model used to train surgeons to resect orbital pathology within any desired orbital compartment. Methods Expansile superabsorbent polymer (SAP) beads (2 mm) were soaked in Omnipaque™ (Iohexol) solution for 15 minutes prior to transcaruncular orbital implantation using 10-gauge angiocath. Insertion depth was designed to implant beads in predetermined intraconal compartments corresponding to established orbital tumor stages. Beads were left to expand in situ over a period of 1 to 5 hours. Computed tomography scans were performed using the FUSION image guidance protocol. Model utility and learning curves were assessed by quantifying resection time over 8 sequential attempts. Results All 24 beads were successfully implanted in 8 orbits corresponding to CHEER stage II to IV lesions (n = 3 per orbit). Beads expanded from 2 mm to an average of 5.2 mm within 1 hour. During expansion, the beads interpolated into the adjacent fascia similar to in vivo tumors. Average insertion time was 5:53 minutes per orbit (range, 3:24–10:33 min) and average time to bead identification was 10:47 minutes. Across all beads, dissection times decreased in a nonsignificant manner over 8 consecutive attempts. Conclusion The directed implantation of expansile SAP beads in this cadaveric model accurately replicates the approach, identification, and resection of isolated orbital lesions. This orbital model can assist the endoscopic surgical team to develop further knowledge and technical skill sets to approach orbital lesions. Further ongoing studies to validate this model are currently underway.

Iris Root Chandelier Illumination for the Management of Advanced Pediatric Tractional Retinal Detachments.

To describe a safe illumination technique in advanced pediatric tractional retinal detachments. A 50-week-old premature infant with stage 5 retinopathy of prematurity was managed utilizing this technique. The surgical technique is demonstrated using a video. A non-trocar chandelier illumination system was used safely to provide adequate illumination for bimanual dissection. This technique allows working under chandelier illumination in a controlled fashion in advanced stages of pediatric ischemic vitreoretinopathies. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:235-237.].

Efficacy and Safety of the Rotational Technique for Endoscopic Transforaminal Excision of Colloid Cysts of the Third Ventricle

The main criticism of endoscopic excision of colloid cysts of the third ventricle is the decreased ability to completely resect the cyst wall, therefore increasing the risk of recurrence. The extent of resection varies widely across the endoscopic series and is largely influenced by the surgical technique. We report the results of the rotational technique for endoscopic transforaminal excision of colloid cysts in a series of consecutive patients. Our objective is to contribute to the current literature and to shed more light on an effective and safe yet less commonly used technique. Retrospective analysis was performed on 19 patients. Preoperative magnetic resonance imaging (MRI) was evaluated for cyst characteristics. Postoperative MRI was evaluated for residual cyst membranes. Operative records were reviewed for residual cyst components. Excision grade was determined based on the Barrow Neurological Institute grading scale. Symptom resolution was documented clinically. The study included 13 men and 6 women, with a mean age of 35 years (range, 19-56 years) and mean follow-up of 27.74 months (range, 4-55 months). Total excision was achieved in 17 of 19 cysts (89.5%). A small residual was seen intraoperatively but not radiographically in 1 patient. In another patient, residual cyst membrane seen intraoperatively and radiologically led to recurrence 18 months postoperatively. No mortalities or permanent morbidities occurred. Our high total excision rate and low complication profile are in concordance with the recent reports of endoscopic resection of colloid cysts. The rotational technique for the endoscopic transforaminal approach is highly effective and a safe alternative to the bimanual dissection technique.

Minimally Invasive Lateral Endoscopic Multiport Approach to the Infratemporal Fossa: A Cadaveric Study.

Expanded endoscopic endonasal approaches to the infratemporal fossa (ITF) are increasingly performed owing to improved visualization and less morbidity compared with classic open approaches. Only a few studies in the literature investigated lateral endoscopic access to the ITF. The aim of this study was to examine the ITF with the minimally invasive endoscopically assisted Gillies approach with a trial of its expansion through a double port technique. The ITF was examined in 10 sides of 5 cadaveric heads using a lateral endoscopic assisted approach. A double portal technique was developed to allow bimanual dissection. Specific long angled skull base instruments were used for dissection under stereotactic guidance. The endoscopic assisted Gillies approach permitted minimally invasive access to the complete anteroposterior extension of the ITF with sufficient mobility of surgical instruments. A new anatomic classification for the ITF from a lateral endoscopic perspective was introduced. The addition of the second port allowed bimanual dissection. This cadaveric study shows the feasibility of an endoscopically assisted lateral approach to the ITF. The addition of a posterior port expands the approach through increasing the working area and enabling a bimanual dissection technique. Performed alone or combined with an anterior endoscopic transnasal approach, this technique offers minimally invasive access to the ITF. The development of specifically designed instruments would further improve this promising approach.

Expanded transcanal transpromontorial approach to the internal auditory canal: Pilot clinical experience.

The aim of this study was to describe and evaluate the feasibility of an expanded transcanal transpromontorial approach, developed from the exclusive endoscopic transcanal transpromontorial approach. Retrospective case series. Retrospective chart review of 10 patients operated by an expanded transcanal transpromontorial approach in two tertiary referral centers (University Hospital of Modena, Italy and University Hospital of Verona, Italy). Data from charts and video documentation were collected and analyzed. Between April 2015 and January 2016, 10 patients underwent an expanded transcanal transpromontorial approach for vestibular schwannoma Koos stage I or II and were enrolled in the study. The size of the tumors ranged from 7 to 19 mm in maximum diameter. A gross total resection was achieved in all cases. One subject experienced postoperative cerebrospinal fluid otorhinorrhea and three subjects experienced temporary postoperative facial weakness, all of which completely resolved. The mean follow-up was 5 months. The expanded transcanal transpromontorial approach allowed bimanual dissection using a microscopic technique for the treatment of pathologies of the internal auditory canal and cerebellopontine angle. This novel approach resulted in minimal morbidity and comparable facial nerve preservation rates to the traditional approaches to the internal auditory canal. The expanded transpromontorial approach to the internal auditory canal holds promise for addressing pathology in this region of the temporal bone from the external auditory canal. 4. Laryngoscope, 127:2608-2614, 2017.

PC01.02 Invasive Staging and Restaging

PC01.02 Invasive Staging and Restaging

Development and preliminary results of bimanual smart micro-surgical system using a ball-lens coupled OCT distance sensor.

Bimanual surgery enhances surgical effectiveness and is required to successfully accomplish complex microsurgical tasks. The essential advantage is the ability to simultaneously grasp tissue with one hand to provide counter traction or exposure, while dissecting with the other. Towards enhancing the precision and safety of bimanual microsurgery we present a bimanual SMART micro-surgical system for a preliminary ex-vivo study. To the best of our knowledge, this is the first demonstration of a handheld bimanual microsurgical system. The essential components include a ball-lens coupled common-path swept source optical coherence tomography sensor. This system effectively suppresses asynchronous hand tremor using two PZT motors in feedback control loop and efficiently assists ambidextrous tasks. It allows precise bimanual dissection of biological tissues with a reduction in operating time as compared to the same tasks performed with conventional one-handed approaches.

High-Definition Exoscope System for Microneurosurgery:Use of an Exoscope in Combination with Tubular Retraction and Frameless Neuronavigation for Microsurgical Resection of Deep Brain Lesions

The high-definition exoscope (VITOM®, Karl Storz GmbH & Co., Tuttlingen, Germany) is a new equipment that can be used as an alternative to the operating microscope in neurosurgery. Several neurosurgeons have recently reported that the exoscope allows for long working distances and great depth of field. Herein, we review reported cases of exoscope use in neurosurgery. We also describe the advantages of the exoscope compared to the operating microscope and endoscope. Furthermore, we introduce a novel technique for microsurgical resection of deep brain lesions, in which the exoscope is used along with tubular retraction and frameless neuronavigation. Before the operation, neuronavigation is registered and the surgical trajectory is planned to avoid damaging the functional cortex and eloquent white matter tracts. By using intraoperative neuronavigation, the tubular retractor (NICO BrainPath®, NICO Corporation, Indianapolis, US), which is designed to split the white matter when gently inserted, is inserted transcortically into the brain to reach the lesion, along the preplanned trajectory. After insertion, the tubular retractor is fixed in place using a self-retaining arm. This creates a narrow corridor that enables the use of the exoscope (for optimum visualization), bimanual dissection technique, and long bayoneted surgical instruments. The large focal distance of the exoscope allows it to be placed sufficiently further away from the surgical site, permitting the passage of long surgical instruments under the scope. Although obtaining surgical access to deep-seated brain lesions is challenging, we consider that this technique facilitates a safe surgical approach for lesions in deep locations.