Image-guided thoracoscopic spinal surgery: a merging of 2 technologies

Video-assisted thoracoscopic image-guided spine surgery: evolution of 19 years of experience, from endoscopy to fully integrated 3D navigation

OBJECTIVE

The purpose of this study was to describe the evolution of thoracoscopic spine surgery from basic endoscopic procedures using fluoroscopy and anatomical localization through developmental iterations to the current technology use in which endoscopy and image-guided surgery are merged with intraoperative CT scanning.

METHODS

The authors provided detailed explanations of their thoracoscopic spine surgery techniques, beginning with their early-generation endoscopy with fluoroscopic localization, which was followed with point surface matching techniques and early image guidance. The authors supplanted this with the modern era of image guidance, thoracoscopic spine surgery, and seamless integration that has reached its current level of refinement.

RESULTS

A retrospective review of single-institution thoracoscopic procedures performed by the senior author over the course of 19 years yielded a total of 160 patients, including 73 women and 87 men. The mean patient age was 55 years, and the range included patients 16-94 years of age. There were no patients with worsened neurological function. One hundred sixteen patients underwent surgery for thoracic disc herniation, 18 for underlying neoplasms with spinal cord compression, 14 for osteomyelitis and discitis, 12 for thoracic deformity with neurological changes, and 8 for traumatic etiologies.

CONCLUSIONS

More than 19 years of experience has revealed the benefits of integrating thoracoscopic spine surgery with intraoperative CT scanning and image-guided surgery, including direct decompression without manipulation of neural elements, superior 3D spatial orientation, and localization of complex spinal anatomy. With the exponential growth of machine learning, robotics, artificial intelligence, and advances in imaging techniques and endoscopic imaging, there may be further refinements of this technique on the horizon.

The posterior approach operation to treat thoracolumbar disc herniation: A minimal 2-year follow-up study

Thoracolumbar disc herniation (TLDH) is a rare and progressively disabling disorder; surgical procedures predispose the subjects to high incidence of complications including recurrence, neurological aggravation, and adjacent segment degeneration.Ten patients with TLDH underwent posterior approach operation in our institution from January, 2006 to December, 2015. The mean preoperative duration of clinical symptoms was 16.5 months. The clinical data including operative time, blood loss, and hospitalization duration were investigated. Furthermore, pre and postoperative neurological status was evaluated by the modified Japanese Orthopedic Association (JOA) scoring system and pain by visual analog scale (VAS) scoring system.The mean operative time was 176.50 ± 20.55 minutes, the mean blood loss was 435.00 ± 89.58 mL, and the mean hospitalization length was 13.30 ± 2.97 days. All patients were followed with a mean period of 35.1 months. The mean JOA score of all patients before operation, at discharge, 3 months after operation, and at last follow-up was 6.50 ± 1.28, 7.60 ± 1.22, 8.90 ± 0.99, and 9.00 ± 0.92, respectively. The differences between the pre and postoperative JOA and VAS scores were significant (P < .05). However, the differences of JOA and VAS scores at postoperative 3 months and final follow-up were not statistically significant.Posterior approach operation is an ideal surgical technique for treatment of TLDH; the operative time, blood loss, hospitalization duration, and symptomatic improvement are favorable.

Modified eggshell procedure via posterior approach for sclerosing thoracic disc herniation: a preliminary study

BACKGROUND

Clinically, sclerosing thoracic disc herniation is a disease with high surgical risk and various complications. Eggshell procedure is a surgical method used by surgeons to treat sclerosing thoracic disc herniation. The aim of this study was to report a modified eggshell procedure to treat sclerosing thoracic disc herniation.

METHODS

Medical records of 25 patients with sclerosing thoracic disc herniation were collected between 2007/01 and 2010/08, including 14 males and 11 females, with an average age of 51.7 years old. Modified eggshell procedure was performed to treat the patients with sclerosing thoracic disc herniation. All patients were followed up. Japanese Orthopaedic Association (JOA) score was used to evaluate the clinical outcomes.

RESULTS

All operations were performed successfully with complication rate of 12 %. There were 2 cases of dural laceration and 1 subdural hematoma. All included patients were followed up for at least 5 years, with the median of 6 years. JOA score of preoperation was 5 (IQR = 1) while it was 8 (IQR = 2) at final follow-up, with significant difference (Mann-Whitney U test, Z = -4.891, P < 0.001). The improvement rate of neurological status was 51.5 ± 23.1 %. According to the classification of improvement rate, there were 15 cases at good level, 8 cases at moderate level, and 2 cases without any improvement.

CONCLUSIONS

Modified eggshell procedure is a safe and effective surgical method when performed to treat sclerosing thoracic disc herniation in the clinical practice.

Introduction: Intraoperative spinal imaging and navigation

Image-guided surgery (IGS) has been evolving since the early 1990s and is now used on a daily basis in the operating theater for spine surgery at many institutions. In the last 5 years, spinal IGS has greatly benefitted from important enhancements including portable intraoperative CT (iCT) coupled with high-speed computerized stereotactic navigation systems and optical-based camera tracking technology.

Image-guided navigation and video-assisted thoracoscopic spine surgery: the second generation

Object

Video-assisted thoracoscopic surgery (VATS) has evolved for treatment of a variety of spinal disorders. Early incorporation with image-guided surgery (IGS) was challenged due to reproducibility and adaptability, limiting the procedure's acceptance. In the present study, the authors report their experience with second-generation IGS and VATS technologies for anterior thoracic minimally invasive spinal (MIS) procedures.

Methods

The surgical procedure is described in detail including operating room set-up, patient positioning (a lateral decubitus position), placement of the spinal reference frame and portal, radiographic localization, registration, surgical instruments, and the image-guided thoracoscopic discectomy.

Results

Combined IGS and VATS procedures were successfully performed and assisted in anatomical localization in 14 patients. The mean patient age was 59 years (range 32–73 years). Disc herniation pathology represented the most common indication for surgery (n = 8 patients); intrathoracic spinal tumors were present in 4 patients and the remaining patients had infection and ossification of the posterior longitudinal ligament. All patients required chest tube drainage postoperatively, and all but 1 patient had drainage discontinued the following day. The only complication was a seroma that was presumed to be due to steroid therapy for postoperative weakness. At the final follow-up, 11 of the patients were improved neurologically, 2 patients had baseline neurological status, and the 1 patient with postoperative weakness was able to ambulate, albeit with an assistive device.

The evolution of thoracoscopic surgical procedures occurring over 20 years is presented, including their limitations. The combination of VATS and IGS technologies is discussed including their safety and the importance of 3D imaging. In cases of large open thoracotomy procedures, surgeries require difficult, extensive, and invasive access through the chest cavity; using a MIS procedure can potentially eliminate many of the complications and morbidities associated with large open procedures. The authors report their experience with thoracic spinal surgeries that involved MIS procedures and the new technologies.

Conclusions

The most significant advance in IGS procedures has resulted from intraoperative CT scanning and automatic registration with the IGS workstation. Image guidance can be used in conjunction with VATS techniques for thoracic discectomy, spinal tumors, infection, and ossification of the posterior longitudinal ligament. The authors' initial experience has revealed this technique to be useful and potentially applicable to other MIS procedures.

Upper thoracic disc disease (T1-T9) in large-breed dogs

The purpose of this study was to identify large-breed dogs with intervertebral disc disease (IVDD) in the upper thoracic region (thoracic vertebrae 1-9 [T1-T9]). Medical records of all dogs that were diagnosed with IVDD on MRI between February 2008 and September 2011 were reviewed. Of 723 dogs diagnosed with IVDD based on MRI, 527 (72.9%) were small-breed dogs. There were 21 (10.7%) large-breed dogs with IVDD in the T1-T9 region, whereas no small-breed dogs were identified with lesions in that region. The most common upper thoracic lesion sites were T2-T3 (33.3%) and T4-T5 (25.9%). The majority of dogs with T1-T9 lesions were German shepherd dogs (52.4%). Larger, older dogs were more likely to have T1-T9 lesions and more likely to have multiple regions with IVDD, in particular German shepherd dogs (35.1%). Dogs with T1-T9 IVDD were more likely to have IVDD in another region (66.7%). All large-breed dogs presenting with T3-L3 myelopathy should have diagnostic imaging performed of their entire thoracic and lumbar spine.

Navigation, robotics, and intraoperative imaging in spinal surgery

Spinal navigation is a technique gaining increasing popularity. Different approaches as CT-based or intraoperative imaging-based navigation are available, requiring different methods of patient registration, bearing certain advantages and disadvantages. So far, a large number of studies assessed the accuracy of pedicle screw implantation in the cervical, thoracic, and lumbar spine, elucidating the advantages of image guidance. However, a clear proof of patient benefit is missing, so far. Spinal navigation is closely related to intraoperative 3D imaging providing an imaging dataset for navigational use and the opportunity for immediate intraoperative assessment of final screw position giving the option of immediate screw revision if necessary. Thus, postoperative imaging and a potential revision surgery for screw correction become dispensable.Different concept of spinal robotics as the DaVinci system and SpineAssist are under investigation.

Computer-assisted navigation in orthopedic surgery

Computer-assisted navigation has a role in some orthopedic procedures. It allows the surgeons to obtain real-time feedback and offers the potential to decrease intra-operative errors and optimize the surgical result. Computer-assisted navigation systems can be active or passive. Active navigation systems can either perform surgical tasks or prohibit the surgeon from moving past a predefined zone. Passive navigation systems provide intraoperative information, which is displayed on a monitor, but the surgeon is free to make any decisions he or she deems necessary. This article reviews the available types of computer-assisted navigation, summarizes the clinical applications and reviews the results of related series using navigation, and informs surgeons of the disadvantages and pitfalls of computer-assisted navigation in orthopedic surgery.

Image-Guided Thoracoscopic Resection of Thoracic Dumbbell Nerve Sheath Tumors

BACKGROUND:

Surgical removal of dumbbell nerve sheath tumors (NSTs) remains challenging because these neoplasms occupy ≥ 2 spinal and extraspinal spaces. The presence of intraspinal extension, tumor dimension, and/or its location within the thoracic cavity have previously made the resection of these types of neoplasms difficult.

OBJECTIVE:

To describe the feasibility of performing minimally invasive thoracoscopic surgery, as facilitated by an image guidance system (IGS), to achieve gross total resection of select dumbbell NSTs located in the thoracic spine.

METHODS:

The 3 cases presented here contained small intraspinal or foraminal components. Preoperative symptoms included Horner syndrome and back and chest wall pain. We used IGS to help guide the complete thoracoscopic resection of select dumbbell NSTs, consisting of extradural, intraforaminal, and paravertebral tumor components, which previously would have been challenging with only a thoracoscopic approach.

RESULTS:

IGS provided continuous intraoperative anatomic orientation to achieve gross total resection in all 3 cases. All surgical and postsurgical outcomes were satisfactory; preoperative symptoms improved or resolved; and no adverse events were observed.

CONCLUSION:

Thoracic dumbbell NSTs that have small intraspinal or foraminal components could be resected thoracoscopically when facilitated by IGS. Image-guided thoracoscopic resection of such dumbbell tumors may not only improve the precision of resection, reduce recurrence, and avoid the need for spinal reconstruction but also obviate the need for more invasive or simultaneous posterior procedures. The IGS enhances the accuracy and safety of 2-dimensional thoracoscopic surgery and may reduce its learning curve.

A miniature patient-mount navigation system for assisting needle placement in CT-guided intervention

BACKGROUND

CT-guided intervention is routinely performed in an iterative fashion that often leads to lengthy operation and high X-ray exposure to patients. To streamline the workflow, we develop a patient-mount navigation system for assisting needle placement in CT-guided interventions.

METHODS

The system comprises three components, a miniature patient-mount tracking unit, an auto-registered reference-frame unit and an intuitive image-processing unit. The system is operated like a virtual biplane fluoroscopy with augmented CT reconstructed images to streamline the conventional CT-guided intervention workflow. Surgery efficiency and safety can be increased, while radiation for patients and surgeons can be reduced. Two preclinical validations were conducted to evaluate the technical applicability and accuracy of the system.

RESULTS

The results of the rigid physical phantom test showed a machine position error of 1.6 mm and a tilting error of 1.5°. The results of the deformable porcine phantom test showed the operation position error to be 3.6 mm and tilting error to be 2.9°.

CONCLUSIONS

We concluded that the accuracy of our system is within the comparable range of the existing navigation systems.

Image-guided spine surgery: state of the art and future directions

Navigation technology is a widely available tool in spine surgery and has become a part of clinical routine in many centers. The issue of where and when navigation technology should be used is still an issue of debate. It is the aim of this study to give an overview on the current knowledge concerning the technical capabilities of image-guided approaches and to discuss possible future directions of research and implementation of this technique. Based on a Medline search total of 1,462 publications published until October 2008 were retrieved. The abstracts were scanned manually for relevance to the topics of navigated spine surgery in the cervical spine, the thoracic spine, the lumbar spine, as well as ventral spine surgery, radiation exposure, tumor surgery and cost-effectivity in navigated spine surgery. Papers not contributing to these subjects were deleted resulting in 276 papers that were included in the analysis. Image-guided approaches have been investigated and partially implemented into clinical routine in virtually any field of spine surgery. However, the data available is mostly limited to small clinical series, case reports or retrospective studies. Only two RCTs and one metaanalysis have been retrieved. Concerning the most popular application of image-guided approaches, pedicle screw insertion, the evidence of clinical benefit in the most critical areas, e.g. the thoracic spine, is still lacking. In many other areas of spine surgery, e.g. ventral spine surgery or tumor surgery, image-guided approaches are still in an experimental stage. The technical development of image-guided techniques has reached a high level as the accuracies that can be achieved technically meet the anatomical demands. However, there is evidence that the interaction between the surgeon ('human factor') and the navigation system is a source of inaccuracy. It is concluded that more effort needs to be spend to understand this interaction.

Timing of Paired Points and Surface Matching Registration in Three-Dimensional (3D) Image-guided Spinal Surgery

Image-guidance can increase the safety and accuracy of spinal instrumentation placement. However, many spine surgeons are reluctant to incorporate spinal image-guidance into their surgical practice due to the perception that it is time-consuming and tedious, especially the task of vertebral registration. The authors evaluated the time required for paired points and surface matching registration when using the BrainLAB (BrainLAB, Westchester, IL) image-guided spine application for spinal surgery cases. The time required to register vertebral segments using paired points and surface matching techniques was assessed in 13 consecutive patients undergoing spinal fusions by the senior author. Overall, 23 vertebral segments were registered spanning from T1 to S1. Note was made of the vertebral segments that required reregistration due to poor accuracy. The average time required to register a single vertebral segment using the paired points and surface matching technique was 117 seconds (1 min 57 s). Average accuracy obtained was 0.9 mm. Inaccurate registration occurred in 3/23 (13%) of the segments requiring a second attempt at registration. In 3/23 (13%) of segments, adequate navigation accuracy was maintained on an adjacent vertebral segment thereby allowing for instrumentation to be placed in that adjacent segment without having to register that segment. Though associated with a learning curve, image-guidance can be used effectively and efficiently in spinal surgery. Average time required for registration of a vertebral segment using the BrainLAB spine application in this study was less than 2 minutes. The average accuracy obtained was 0.9 mm.

Image guided surgery: New technology for surgery of soft tissue and bone sarcomas

AIM

Providing the surgical oncologist with a new means of performing safe and radical sarcoma surgery with the help of image guidance technology.

METHOD

Two patients with pelvic sarcomas were operated upon with the help of an intra-operative navigation system. The technology of image guided surgery is described in one patient with a retroperitoneal sarcoma invading the bony pelvis and another patient with a chondrosarcoma of the iliac crest.

RESULTS

We show that this new procedure enables optimal radical surgical resection with minimal treatment related morbidity or loss of function.

CONCLUSION

Image guided surgery is a new technical tool in sarcoma surgery.