Factors affecting accuracy and fusion rate in lumbosacral fusion surgery - a preclinical and clinical study

Lumbosacral fusion surgery is indicated in symptomatic degenerative lumbosacral disorder, when the origin of pain is demonstrated to lie within the restricted number of functional spinal units and when the pain is refractory to the conservative treatment, to eliminate painful motion of the spinal units. Inaccurate placement of pedicle screws may cause neurological symptoms, and result in early hardware failure and return of spinal instability symptoms. All spinal instrumentation eventually fails without solid bony fusion, and the presence of symptomatic bony non-union at least a year after fusion surgery is defined as pseudoarthrosis. Bioactive glasses (BAGs) are synthetic, biocompatible, osteoconductive and osteostimulative materials with angiogenic and antibacterial properties, able to bond to bone. In a study of 147 patients and 837 pedicle screws placed due to degenerative lumbosacral spine disorder, 14.3 % breached the pedicle. New neurological symptoms corresponding to the breach were observed in 25.9 % of patients with pedicle breach, and 89.2 % of the symptomatic breaches were either medially or inferiorly. A preclinical controlled study of novel BAG S53P4 putty showed good biocompatibility, slightly higher intramedullary ossification of putty group compared to the control group, and that the binder agent did not disturb formation of new bone in vivo. The interbody fusion rate was 95.8 % with BAG S53P4 putty as bone graft expander with autograft in clinical lumbosacral interbody fusion, indicating at least as good interbody fusion results as the presently used materials. One early operative subsidence remaining unchanged over the study period was observed with putty.Lannerangan luudutusleikkausten tarkkuuteen ja luutumiseen vaikuttavat tekijät Lannerangan luudutusleikkaus voidaan tehdä oireisessa lannerangan rappeumasairaudessa, kun kivun syyn on osoitettu sijaitsevan rajallisessa määrässä selkärangan toiminnallisia yksikköjä ja kun kipu ei vähene leikkauksettomilla hoidoilla. Leikkauksella voidaan poistaa kipua tuottava selkärangan toiminnallisten yksikköjen liike. Epätarkka pedikkeliruuvien asettaminen voi aiheuttaa neurologisia oireita ja johtaa nopeaan kiinnitysosien irtoamiseen ja rangan epätukevuusoireiden palaamiseen. Suuri osa selkärangan kiinnityslaitteista irtoaa lopulta, jollei luutumista kiinnitettyjen kohtien välillä tapahdu. Vuoden kuluttua luudutusleikkauksesta oireista luutumatonta kiinnityskohtaa nimitetään pseudoartroosiksi. Bioaktiiviset lasit ovat synteettisiä, bioyhteensopivia, osteokonduktiivisia ja osteostimulatiivisia materiaaleja, joilla on angiogeenisiä ja antibakteerisia ominaisuuksia, ja ne voivat sitoutua suoraan luuhun. 147 potilaalle lannerangan rappeumasairauden vuoksi asetetut 837 pedikkeliruuvia käsittävän tutkimuksen mukaan 14.3 % ruuveista rikkoi luisen pedikkelin seinämän. 25.9 %:lla potilaista, joilla ruuvi läpäisi pedikkelin seinämän, ilmeni uusia neurologisia oireita, ja 89.2 %:lla oireisista potilaista pedikkeliruuvi läpäisi pedikkelin seinämän mediaalisesti tai inferiorisesti. Prekliinisessä kontrolloidussa tutkimuksessa uudenlainen bioaktiivisesta lasista valmistettu S53P4 luunkorviketahna todettiin bioyhteensopivaksi, ja sen avulla saavutettiin hieman vertailuryhmää parempi luutuminen luuydinontelossa. Tahnan sidosaineen ei eläinkokeessa todettu häiritsevän luun muodostumista. Kliinisessä tutkimuksessa saavutettiin 95.8 %:n luutuminen käytettäessä S53P4 biolasitahnaa yhdessä oman luun kanssa lannerangan nikamasolmujen välisessä luudutuksessa. Siten yhdessä oman luun kanssa käytettäessä S53P4 biolasitahnalla saadaan aikaan vähintään yhtä hyvä nikamasolmujen välinen luutuminen kuin nykyisin käytettävillä synteettisillä luunkorvikkeilla. Tutkimuksessa todettiin yksi leikkauksen yhteydessä tapahtunut nikamasolmujen välisen implantin päätelevyyn painuminen, jonka suuruus ei muuttunut seurantakuvantamisissa

Integrated Neuromusculoskeletal Modeling within a Finite Element Framework to Investigate Mechanisms and Treatment of Neurodegenerative Conditions

Neurodegenerative and neurodevelopmental disorders are a group of conditions that stem from irregularities in the nervous system that lead to complications in function and movement. The goal of this work is to develop computational tools that: (1) measure the accuracy of surgical interventions in neurodegenerative and neurodevelopmental conditions, and (2) integrate neural and musculoskeletal frameworks to provide a platform to better investigate neurodegenerative and neurodevelopmental disorders. Parkinson’s disease (PD) is a neurodegenerative condition projected to affect over 1.2 million people by 2030 in the US. It is caused by atypical firing patterns in the basal ganglia region of the brain that leads to primary motor symptoms of tremor, slowness of movement, and rigidity. A potential treatment for PD is deep brain stimulation (DBS). DBS involves implanting electrodes into central brain structures to regulate the pathological signaling. Electrode placement accuracy is a key metric that helps to determine patient outcomes postoperatively. An automated measurement system was developed to quantify electrode placement accuracy in robot-assisted asleep DBS procedures (Chapter 2). This measurement system allows for precise metrics without human bias in large cohorts of patients. This measurement system was later modified to measure screw placement accuracy in spinal fusion procedures for the treatment of degenerative musculoskeletal conditions (Chapter 3). DBS is an effective treatment for PD, but it is not a cure for the cause of the disease itself. To cure neurodegenerative and neurodevelopmental diseases, the underlying disease mechanisms must be better understood. A major limitation in studying neural conditions is the infeasibility of performing in vivo experiments, particularly in humans due to ethical considerations. Computational modeling, specifically fully predictive neuromusculoskeletal (NMS) models, can help to accumulate additional knowledge about neural pathways that cannot be determined experimentally. NMS models typically include complexity in either the neuromuscular or musculoskeletal system, but not both, making it difficult or infeasible to investigate the relationship between neural signaling and musculoskeletal function. To overcome this, a fully predictive NMS model was developed by integrating NEURON software within Abaqus, a finite element (FE) environment (Chapter 4). The neural model consisted of a pool of motor neurons innervating the soleus muscle in a FE human ankle model. Software integration was verified against previously published data, and the neuronal network was verified for motor unit recruitment and rate coding, which are the two principles required for in vivo muscle generation. To demonstrate the applicability of the model to study neurodegenerative and neurodevelopmental diseases, a fully predictive mouse hindlimb NMS model was developed using the integrated framework to investigate Rett syndrome (RS) (Chapter 5). RS is a neurodevelopmental disorder caused by a mutation of the Mecp2 gene with hallmark motor symptoms of a loss of purposeful hand movement, changes in muscle tone, and a loss of speech. Recent experimental analysis has found that the axon initial segment (AIS) in mice that model RS has torsional morphology compared to wildtype littermate controls. The effects these neural morphological changes have on joint motion will be studied using the mouse NMS model. This work encompasses a range of research that uses computational models to study the underlying mechanisms and design targeted treatment options for neurodegenerative and neurodevelopmental disorders. The outcomes of this work have quantified the accuracy at which surgical interventions for these conditions can be performed and have resulted in a neuromusculoskeletal model that can be applied to understand how neural morphology, and associated changes due to these disorders, affects musculoskeletal function

Assessing the accuracy of a new 3D2D registration algorithm based on a non-invasive skin marker model for navigated spine surgery

Purpose: We assessed the accuracy of a new 3D2D registration algorithm to be used for navigated spine surgery and explored anatomical and radiologic parameters affecting the registration accuracy. Compared to existing 3D2D registration algorithms, the algorithm does not need bone-mounted or table-mounted instruments for registration. Neither does the intraoperative imaging device have to be tracked or calibrated. Methods: The rigid registration algorithm required imaging data (a pre-existing CT scan (3D) and two angulated fluoroscopic images (2D)) to register positions of vertebrae in 3D and is based on non-invasive skin markers. The algorithm registered five adjacent vertebrae and was tested in the thoracic and lumbar spine from three human cadaveric specimens. The registration accuracy was calculated for each registered vertebra and measured with the target registration error (TRE) in millimeters. We used multivariable analysis to identify parameters independently affecting the algorithm’s accuracy such as the angulation between the two fluoroscopic images (between 40° and 90°), the detector-skin distance, the number of skin markers applied, and waist circumference. Results: The algorithm registered 780 vertebrae with a median TRE of 0.51 mm [interquartile range 0.32–0.73 mm] and a maximum TRE of 2.06 mm. The TRE was most affected by the angulation between the two fluoroscopic images obtained (p < 0.001): larger angulations resulted in higher accuracy. The algorithm was more accurate in thoracic vertebrae (p = 0.004) and in the specimen with the smallest waist circumference (p = 0.003). The algorithm registered all five adjacent vertebrae with similar accuracy. Conclusion: We studied the accuracy of a new 3D2D registration algorithm based on non-invasive skin markers. The algorithm registered five adjacent vertebrae with similar accuracy in the thoracic and lumbar spine and showed a maximum target registration error of approximately 2 mm. To further evaluate its potential for navigated spine surgery, the algorithm may now be integrated into a complete navigation system

Robots and tools for remodeling bone

The field of robotic surgery has progressed from small teams of researchers repurposing industrial robots, to a competitive and highly innovative subsection of the medical device industry. Surgical robots allow surgeons to perform tasks with greater ease, accuracy, or safety, and fall under one of four levels of autonomy; active, semi-active, passive, and remote manipulator. The increased accuracy afforded by surgical robots has allowed for cementless hip arthroplasty, improved postoperative alignment following knee arthroplasty, and reduced duration of intraoperative fluoroscopy among other benefits. Cutting of bone has historically used tools such as hand saws and drills, with other elaborate cutting tools now used routinely to remodel bone. Improvements in cutting accuracy and additional options for safety and monitoring during surgery give robotic surgeries some advantages over conventional techniques. This article aims to provide an overview of current robots and tools with a common target tissue of bone, proposes a new process for defining the level of autonomy for a surgical robot, and examines future directions in robotic surgery

The of Application of 3D-Printing to Lumbar Spine Surgery

Rapid prototyping refers to the manufacturing process in which a three-dimensional (3D) digital model can be transformed into a physical model by layering material in the shape of successive cross sections atop of previously layers. Rapid prototyping has been increasing in popularity in the field of medicine and surgery due to the ability to personalize various aspects of patient care. The thesis will explore the use of rapid prototyping in lumbar spine surgery, aim to quantify the accuracy of medical imaging when relating to imaged structures and their corresponding models produced by rapid prototyping, and determine if complex patient-specific guides are accurate and safe

Sonification as a Reliable Alternative to Conventional Visual Surgical Navigation

Despite the undeniable advantages of image-guided surgical assistance systems in terms of accuracy, such systems have not yet fully met surgeons' needs or expectations regarding usability, time efficiency, and their integration into the surgical workflow. On the other hand, perceptual studies have shown that presenting independent but causally correlated information via multimodal feedback involving different sensory modalities can improve task performance. This article investigates an alternative method for computer-assisted surgical navigation, introduces a novel sonification methodology for navigated pedicle screw placement, and discusses advanced solutions based on multisensory feedback. The proposed method comprises a novel sonification solution for alignment tasks in four degrees of freedom based on frequency modulation (FM) synthesis. We compared the resulting accuracy and execution time of the proposed sonification method with visual navigation, which is currently considered the state of the art. We conducted a phantom study in which 17 surgeons executed the pedicle screw placement task in the lumbar spine, guided by either the proposed sonification-based or the traditional visual navigation method. The results demonstrated that the proposed method is as accurate as the state of the art while decreasing the surgeon's need to focus on visual navigation displays instead of the natural focus on surgical tools and targeted anatomy during task execution

Comparison of robot versus fluoroscopy-assisted pedicle screw instrumentation in adolescent idiopathic scoliosis surgery: A retrospective study

The aim of this study was to explore whether a robot-assisted (RA) technique has advantages over the conventional fluoroscopy-assisted (FA) technique in clinical and radiological outcomes and whether it could decrease the incidence of mis-implantations of pedicle screws in adolescent idiopathic scoliosis (AIS) correction surgery. A total of 101 patients with AIS were recruited (RA group: 45 patients underwent RA screw insertion; FA group: 56 patients underwent FA screw insertion). When comparing the radiological data between the two groups, the major and secondary curves were both corrected proficiently with no difference in Cobb angle comparison at the last follow-up, suggesting that both the RA technique and the FA technique could lead to efficient radiographic correction and similar clinical outcomes (all, p &gt; 0.05). In the RA group, operation time, blood loss, and transfusion volume were significantly greater than those in the FA group, while the accuracy of screw implantations in patients with AIS with a thoracic scoliotic curve in the RA group was higher than that in the FA group. In conclusion, both the RA and FA techniques could approach proficient radiographic correction and similar clinical outcomes in AIS surgery. Compared with the conventional fluoroscopy technique, the RA technique might improve the accuracy of screw implantations in patients with AIS with a thoracic scoliotic curve, while the increased operation time, blood loss, and transfusion volume might be the disadvantages due to the preliminary stage of the learning curve

ADVANCED INTRAOPERATIVE IMAGE REGISTRATION FOR PLANNING AND GUIDANCE OF ROBOT-ASSISTED SURGERY

Robot-assisted surgery offers improved accuracy, precision, safety, and workflow for a variety of surgical procedures spanning different surgical contexts (e.g., neurosurgery, pulmonary interventions, orthopaedics). These systems can assist with implant placement, drilling, bone resection, and biopsy while reducing human errors (e.g., hand tremors and limited dexterity) and easing the workflow of such tasks. Furthermore, such systems can reduce radiation dose to the clinician in fluoroscopically-guided procedures since many robots can perform their task in the imaging field-of-view (FOV) without the surgeon. Robot-assisted surgery requires (1) a preoperative plan defined relative to the patient that instructs the robot to perform a task, (2) intraoperative registration of the patient to transform the planning data into the intraoperative space, and (3) intraoperative registration of the robot to the patient to guide the robot to execute the plan. However, despite the operational improvements achieved using robot-assisted surgery, there are geometric inaccuracies and significant challenges to workflow associated with (1-3) that impact widespread adoption. This thesis aims to address these challenges by using image registration to plan and guide robot- assisted surgical (RAS) systems to encourage greater adoption of robotic-assistance across surgical contexts (in this work, spinal neurosurgery, pulmonary interventions, and orthopaedic trauma). The proposed methods will also be compatible with diverse imaging and robotic platforms (including low-cost systems) to improve the accessibility of RAS systems for a wide range of hospital and use settings. This dissertation advances important components of image-guided, robot-assisted surgery, including: (1) automatic target planning using statistical models and surgeon-specific atlases for application in spinal neurosurgery; (2) intraoperative registration and guidance of a robot to the planning data using 3D-2D image registration (i.e., an “image-guided robot”) for assisting pelvic orthopaedic trauma; (3) advanced methods for intraoperative registration of planning data in deformable anatomy for guiding pulmonary interventions; and (4) extension of image-guided robotics in a piecewise rigid, multi-body context in which the robot directly manipulates anatomy for assisting ankle orthopaedic trauma

Clinical efficacy of minimally invasive transforaminal lumbar interbody fusion and endoscopic lumbar interbody fusion in the treatment of lumbar degenerative diseases

Objective To compare the safety and clinical efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and endoscopic lumbar interbody fusion (Endo-LIF) for lumbar degenerative diseases. Methods A retrospective analysis was conducted on the data of 115 patients diagnosed with lumbar degenerative disease at Ningguo People's Hospital and Hangzhou First People's Hospital from January 2019 to July 2021, including 54 cases in the MIS-TLIF group and 61 cases in the Endo-LIF group. The clinical outcomes were compared before operation, and at 1 week, 1 month, 3 months and 1-year post-operation, including visual analogue scale (VAS), Oswestry disability index scores (ODI) and modified MacNab criteria. Results The surgical time in the Endo-LIF group was longer than that in the MIS-TLIF group ［(155.61±8.50) min vs (128.00±8.40) min］; however, the surgical bleeding volume ［(60.39±5.54) mL vs (129.39±8.59) mL］ and hospital stay ［(3.91±0.74) d vs (4.96±1.57) d］ in the Endo-LIF group were lower than those in the MIS-TLIF group, and the differences were statistically significant (P＜0.05). The VAS score of low back pain and ODI score in the two groups at each time point after operation were significantly lower than those before operation (P＜0.05). At 3 month, 1-year post-operation, the VAS score of the Endo-LIF group was lower than that of the MIS-TLIF group(P＜0.05). The 1-year post-operation MacNab efficacy evaluation showed no statistically significant difference in the excellent and good rates between the MIS-TLIF group and the Endo-LIF group (96.3% vs 96.7%, χ2=0.149, P＞0.05). Conclusion There was no significant difference in mediumshort term surgical outcomes between MIS-TLIF and Endo-LIF. Endo-LIF group has less damage to surrounding tissues, less intraoperative blood loss, and less low-back pain, which is more conducive to the recovery of patients in the long run. However, the indications of Endo-LIF are relatively limited, and the learning curve of Endo-LIF is deep, surgeons need to select indications strictly