Radiofrequency ablation under 3D intraoperative Iso-C C-arm navigation for the treatment of osteoid osteomas

Robot-assisted Percutaneous Radiofrequency Ablation for the Treatment of Osteoid Osteomas

OBJECTIVE

Percutaneous CT-guided radiofrequency ablation (CT-RFA) is a widely accepted procedure for treatment of osteoid osteomas. However, the application of CT-RFA was restricted as a result of some drawbacks, such as radiation exposure, and inconvenience in general anesthesia. The primary aim of this study is to evaluate the safety and efficacy of intra-operative TiRobot-assisted percutaneous RFA of osteoid osteomas.

METHODS

We retrospectively reviewed 21 medical files of patients who were treated with percutaneous RFA of osteoid osteomas guided by the TiRobot system in our institution between March 2021 and April 2022. The three-dimensional images obtained by a 3D C-arm intra-operatively were sent to the TiRobot system. The puncture point and trajectory were designed. Then the guide pin was positioned to the lesion with the assistance of TiRobot and the biopsy sheath was inserted into the lesion through the guide pin. The tumor was biopsied for pathological examination. Then the RFA needle was inserted into the nidus through the biopsy sheath for thermal ablation. Data were extracted on the associated complications, the reduction in pain at 1 month and 1 year postoperatively assessed by the visual analogue scale (VAS). A paired t-test was used to compare the pre-operative and post-operative VAS scores.

RESULTS

The patients included 17 males and four females with a mean age of 19.5 ± 10.4 years (range 3-45 years). Lesions were located on the femur in nine cases, on the tibia in nine cases, on the humerus in one case, on the calcaneus in one case, and on the acetabulum in one case. TiRobot-assisted percutaneous RFA was successfully performed on all 21 patients. There was no intra-operative or post-operative complications observed. Pathological diagnosis of osteoid osteoma was obtained in 11 patients, but the other 10 cases were not pathologically diagnosed. The mean follow-up time was 18.8 months (range: 12-26 months).Post-operative VAS scores were reduced significantly in all cases. The mean VAS score decreased from 6.5 pre-operatively to 0.5 at 1 month post-operatively and to 0.1 at 1 year post-operatively.

CONCLUSION

As a reliable technique for localizing and resection of nidus, TiRobot-assisted percutaneous RFA is a safe and effective option for the treatment of osteoid osteomas.

[Short-term effectiveness of orthopedic robot-assisted resection for osteoid osteoma]

Objective

To investigate short-term effectiveness and clinical application advantages of orthopedic robot-assisted resection for osteoid osteoma compared with traditional open surgery.

Methods

A retrospective analysis was conducted on clinical data of 48 osteoid osteoma patients who met the selection criteria between July 2022 and April 2023. Among them, 23 patients underwent orthopedic robot-assisted resection (robot-assisted surgery group), and 25 patients received traditional open surgery (traditional surgery group). There was no significant difference ( P>0.05) in gender, age, disease duration, lesion location and size, and preoperative visual analogue scale (VAS) score, and musculoskeletal tumor society (MSTS) score between the two groups. The surgical time, intraoperative blood loss, intraoperative lesion localization time, initial localization success rate, infection, and recurrence were recorded and compared. VAS scores before surgery and at 24 hours, 1, 3, 6, and 9 months after surgery and MSTS score before surgery and at 3 months after surgery were assessed.

Results

All patients completed the surgery successfully, with no significant difference in surgical time between the two groups ( P>0.05). Compared to the traditional surgery group, the robot-assisted surgery group had less intraoperative blood loss, shorter lesion localization time, and shorter hospitalization time, with significant differences ( P<0.05). The initial localization success rate was higher in the robot-assisted surgery group than in the traditional surgery group, but the difference between the two groups was not significant ( P>0.05). All patients in both groups were followed up, with the follow-up time of 3-12 months in the robot-assisted surgery group (median, 6 months) and 3-14 months in the traditional surgery group (median, 6 months). The postoperative MSTS scores of both groups improved significantly when compared to those before surgery ( P<0.05), but there was no significant difference in the changes in MSTS scores between the two groups ( P>0.05). The postoperative VAS scores of both groups showed a gradually decreasing trend over time ( P<0.05), but there was no significant difference between the two groups after surgery ( P>0.05). During follow-up, except for 1 case of postoperative infection in the traditional surgery group, there was no infections or recurrences in other cases. There was no significant difference in the incidence of postoperative infection between the two groups ( P>0.05).

Conclusion

Orthopedic robot-assisted osteoid osteoma resection achieves similar short-term effectiveness when compared to traditional open surgery, with shorter lesion localization time.

Computer-Assisted Navigation Full Visualization Spinal Endoscopic Surgery for Lumbar Vertebral Osteoid Osteoma

BACKGROUND

Osteoid osteoma is a benign osteogenic tumor that occurs mostly in the femoral stem, while osteoid osteoma occurring in the lumbar vertebral body is a relatively rare case. To minimize treatment-related complications, a computer-assisted navigation fully visualized spinal endoscopy was used. Ultimately, the pathology was diagnosed as osteoid osteoma.

CASE PRESENTATION

We report a 19-year-old adult male with low back pain that worsened at night and CT, MRI imaging showed an abnormal signal shadow at the posterior margin of the lumbar vertebral body. Due to the proximity of the lesion to the spinal canal and adjacent to the nerve roots, it was difficult to precisely localize the lesion by purely endoscopic or open procedures, and if necessary, the resection of surrounding tissues had to be expanded, causing unnecessary damage to the surrounding tissues. Therefore, we choose computer-assisted navigation fully visualized spinal endoscopy to perform the treatment.

CONCLUSION

In this case, we report an osteoid osteoma that occurs less frequently in the lumbar vertebral body. Using computer-assisted navigation with fully visualized spinal endoscopy, we successfully resected the osteoid osteoma at the posterior margin of the L3 vertebral body preoperatively by computer-planned path with intraoperative visualization endoscopy, minimizing the damage to spinal stability. Computer-assisted navigation with visualization endoscopy provides a more precise and minimally invasive approach to the treatment of osteoid osteoma of the spine.

Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the upper extremity: A series of 19 cases

The surgical treatment for osteoid osteoma (OO) in the upper extremity is challenging due to the difficulty in locating the lesion and the crowding of sensitive structures within the anatomy. This study aimed to describe the outcomes of navigated minimally invasive radiofrequency ablation and those of navigated mini open-intralesional curettage in treating these lesions. Nineteen consecutive patients with OO in the upper limb who underwent navigated surgery were included. The average QuickDASH and Numeric Pain Rating Scale improved from 62.2 ± 23.7 to 11.7 ± 16.9 and from 8.1 ± 1.6 to 0.5 ± 1.8, respectively (p < .01 each) following the procedure. Two complications were recorded: one patient had persistent radial nerve palsy, and one patient had transient partial radial nerve weakness. In conclusion, navigation is an important tool in the surgical treatment of OO in the upper limb. A mini open approach to identify and protect neurovascular structures is recommended.

Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the foot and ankle - A series of 14 cases

BACKGROUND

The surgical treatment for osteoid osteoma (OO) in the foot and ankle is challenging. It is difficult to locate the lesion and the anatomy is crowded by sensitive structures. The purpose of this study was to describe the outcomes of navigated mini open-intralesional curettage (NMIC) or navigated minimally invasive radiofrequency ablation (NMRFA) in treating these lesions.

METHODS

All patients who underwent surgery for OO in the foot and ankle between 2015 and 2020 were included. O-arm navigation was used in All procedures. The choice of NMIC versus NMRFA was made by the surgeon according to the location of the lesion and its proximity to sensitive anatomic structures.

RESULTS

Fourteen patients were included. Ten were operated by NMRFA and 4 by NMIC. All patients' symptoms related to OO resolved following a single procedure. Average AOFAS score increased by 18.7 (P < .001). Three patients had the following complications: pathologic fracture, superficial infection and transient deep peroneal nerve sensory loss.

CONCLUSION

Navigated surgical treatment of OO in the foot and ankle is accurate, efficient and safe.

Current Approaches to Osteoid Osteoma and Minimally Invasive Surgery-A Minireview and a Case Report

Osteoid osteoma is a benign bone tumor typically affecting the long bones of the lower limbs in young male patients. The lesion can be asymptomatic but, in most cases, patients present with characteristic nocturnal pain that is very responsive to the administration of non-steroidal anti-inflammatory drugs. Although osteoid osteomas can regress spontaneously over time, surgical therapy is often indicated in cases of long-lasting resistant pain. Apart from a traditional open resection, the modalities of minimally invasive surgery, such as radiofrequency ablation or cryoablation, have gradually become the option of choice in most cases. The first part of this manuscript is a minireview of the contemporary literature on the pathogenesis, diagnosis, and current trends in the treatment of osteoid osteoma. The second part is a case report of our own experience with a conventional C-arm-guided radiofrequency ablation of an osteoid osteoma located in the femoral neck in an adolescent patient. The aim was to prove that, even when more sophisticated guiding devices (CT, O-arm, etc.) are not available, the safe and reliable ablation of the lesion using a C-arm is still possible even in hard-to-reach areas. The case was a success, with no perioperative or postoperative complications.

The surgical management of osteoid osteoma: A systematic review

Background

Osteoid osteoma (OO) comprises approximately 11%-14% of benign bone tumors. The main symptom of OO is localized pain accompanied by nighttime aggravation. Surgical treatment is frequently used in clinic, including open surgery and percutaneous ablation, the latter including radiofrequency ablation, cryoablation, and microwave ablation, but there is no consensus on when and how to choose the best treatment for OO.

Purpose

We did a systematic review of the literature on existing surgical treatments of OO to assess the safety and efficacy of surgical treatments of OO and to evaluate the surgical options for different locations of OO.

Methods

The inclusion criteria in the literature are 1. Patients diagnosed with osteoid osteoma and treated surgically; 2. Include at least five patients; 3. Perioperative visual analogue scale (VAS), postoperative complications, and recurrence were recorded; 4. Literature available in PubMed from January 2014 to December 2021.

Results

In the cohort, 1565 patients (mainly adolescents) with OO received 1615 treatments. And there are 70 patients with postoperative recurrence and 93 patients with postoperative complications (minor: major=84:9). The results of Kruskal-Wallis examination of each experimental index in this experiment were clinical success rate H=14.818, p=0.002, postoperative short-term VAS score H=212.858, p<0.001, postoperative long-term VAS score H=122.290, p<0.001, complication rate H=102.799, p<0.001, recurrence rate H=17.655, p<0.001, the technical success rate was H=45.708, p<0.001, according to the test criteria of α=0.05, H0 was rejected. The overall means of the outcome index in each group were not completely equal.

Conclusion

Percutaneous ablation and open surgery are safe and reliable for OOs, and the technical success rate of percutaneous ablation is higher than that of open surgery. Open surgery and cryoablation can be selected for OOs close to the nerve and atypical sites, while radiofrequency ablation and microwave ablation can be selected for OOs in most other sites.

Does the use of intraoperative CT scan improve outcomes in Orthopaedic surgery? A systematic review and meta-analysis of 871 cases

BACKGROUND

Intraoperative imaging is frequently made use of in Orthopaedic surgery. Historically, conventional 2-dimensional fluoroscopy has been extensively used for this purpose. However, 2D imaging falls short when it is required to visualise complex anatomical regions such as pelvis, spine, foot and ankle etc. Intraoperative 3D imaging was introduced to counter these limitations, and is increasingly being employed in various sub-specialities of Orthopaedic Surgery.

OBJECTIVES

This review aims to outline the clinical and radiological outcomes of surgeries done under the guidance of intraoperative 3D imaging and compare them to those done under conventional 2D fluoroscopy.

METHODS

Three electronic databases (PubMed, Embase and Scopus) were searched for relevant studies that directly compared intraoperative 3D imaging with conventional fluoroscopy. Case series on intraoperative 3D imaging were also included for qualitative synthesis. The outcomes evaluated included accuracy of implant placement, mean surgical duration and rate of revision surgery due to faulty implants.

RESULTS

A total of 31 studies from sub-specialities of spine surgery, pelvi-acetabular surgery, foot and ankle surgery and trauma surgery, having data on a total of 658 patients were analysed. The study groups which had access to intraoperative 3D imaging was found to have significantly increased accuracy of implant positioning (Odds Ratio 0.35 [0.20, 0.62], p = 0.0002) without statistically significant difference in mean surgical time (p = 0.57). Analysis of the studies that included clinical follow up showed that the use of intraoperative 3D imaging led to a significant decrease in the need for revision surgeries due to faulty implant placement.

CONCLUSION

There is sufficient evidence that the application of intraoperative 3D imaging leads to precise implant positioning and improves the radiological outcome. Further research in the form of prospective studies with long term follow up is required to determine whether this superior radiological outcome translates to better clinical results in the long run.

Evaluation of an Ultrasound-Based Navigation System for Spine Neurosurgery: A Porcine Cadaver Study

BACKGROUND

With the growing incidence of patients receiving surgical treatment for spinal metastatic tumours, there is a need for developing cost-efficient and radiation-free alternatives for spinal interventions. In this paper, we evaluate the capabilities and limitations of an image-guided neurosurgery (IGNS) system that uses intraoperative ultrasound (iUS) imaging for guidance.

METHODS

Using a lumbosacral section of a porcine cadaver, we explored the impact of CT image resolution, ultrasound depth and ultrasound frequency on system accuracy, robustness and effectiveness. Preoperative CT images with an isotropic resolution of , and were acquired. During surgery, vertebrae L1 to L6 were exposed. For each vertebra, five iUS scans were acquired using two depth parameters (5 cm and 7 cm) and two frequencies (6 MHz and 12 MHz). A total of 120 acquisition trials were evaluated. Ultrasound-based registration performance is compared to the standard alignment procedure using intraoperative CT. We report target registration error (TRE) and computation time. In addition, the scans' trajectories were analyzed to identify vertebral regions that provide the most relevant features for the alignment.

RESULTS

For all acquisitions, the median TRE ranged from 1.42 mm to 1.58 mm and the overall computation time was 9.04 s ± 1.58 s. Fourteen out of 120 iUS acquisitions (11.66%) yielded a level-to-level mismatch (and these are included in the accuracy measurements reported). No significant effect on accuracy was found with CT resolution (F (2,10) = 1.70, p = 0.232), depth (F (1,5) = 0.22, p= 0.659) nor frequency (F (1,5) = 1.02, p = 0.359). While misalignment increases linearly with the distance from the imaged vertebra, accuracy was satisfactory for directly adjacent levels. A significant relationship was found between iUS scan coverage of laminae and articular processes, and accuracy.

CONCLUSION

Intraoperative ultrasound can be used for spine surgery neuronavigation. We demonstrated that the IGNS system yield acceptable accuracy and high efficiency compared to the standard CT-based navigation procedure. The flexibility of the iUS acquisitions can have repercussions on the system performance, which are not fully identified. Further investigation is needed to understand the relationship between iUS acquisition and alignment performance.

CT-guided radiofrequency ablation for osteoid osteomas: a systematic review

OBJECTIVES

CT-guided radiofrequency ablation (CT-RFA) is considered to be the gold standard for treatment of osteoid osteoma (OO) yet treatment failures (TFs) continue to be reported. This systematic review was conducted to evaluate factors associated with TF, such as ablation time, lesion location, and patient age as well as evaluating how TF has trended over time.

METHODS

Original studies reporting on patients undergoing CT-RFA of OO published between 2002 and 2019 were identified. TF was defined as patients with (1) recurrent or persistent pain +/- (2) imaging evidence of persistent OO. TFs were subdivided into those occurring after the index procedure (primary TF) or those occurring after repeat RFA (secondary TF). Subgroup analysis was performed for TF based on the study date (2002-2010 or 2010-2019), time duration of ablation at 90 °C (6 min or > 6 min), patient age, and tumor location (spinal vs. appendicular).

RESULTS

Sixty-nine studies were included for a total of 3023 patients. The global primary TF rate was 8.3% whereas the secondary TF rate was 3.1%. The TF rate reported in studies published after 2011(7%) was about half that during the earlier time period 2002-2010 (14%). There was no statistical difference in TF corrected for age, OO location, or duration of ablation (respectively p = 0.39, 0.13, and 0.23). The global complication rate was 3%, the most frequent being skin burns (n = 24; 0.7%).

CONCLUSIONS

A decrease in TF observed between 2011-2019 compared to 2002-2010 may reflect improvements in operator technique or advancements in equipment. Duration of ablation, patient age, or location of OO failed to significantly correlate with TF.

KEY POINTS

• CT-guided radiofrequency ablation of osteoid osteomas is a safe technique with a low rate of treatment failure (8.3% failure rate after the primary radiofrequency reducing to 3.1% following a secondary treatment). • The treatment failure rate has decreased over time, possibly due to an improved understanding of the disease process, better technique, and advances in equipment. • Duration of ablation, patient age, or lesion location did not significantly correlate with treatment failure.

The Role of Minimal Access Surgery in the Treatment of Spinal Metastatic Tumors

STUDY DESIGN

Literature review.

OBJECTIVE

To provide an overview of the recent advances in minimal access surgery (MAS) for spinal metastases.

METHODS

Literature review.

RESULTS

Experience gained from MAS in the trauma, degenerative and deformity settings has paved the road for MAS techniques for spinal cancer. Current MAS techniques for the treatment of spinal metastases include percutaneous instrumentation, mini-open approaches for decompression and tumor resection with or without tubular/expandable retractors and thoracoscopy/endoscopy. Cancer care requires a multidisciplinary effort and adherence to treatment algorithms facilitates decision making, ultimately improving patient outcomes. Specific algorithms exist to help guide decisions for MAS for extradural spinal metastases. One major paradigm shift has been the implementation of percutaneous stabilization for treatment of neoplastic spinal instability. Percutaneous stabilization can be enhanced with cement augmentation for increased durability and pain palliation. Unlike osteoporotic fractures, kyphoplasty and vertebroplasty are known to be effective therapies for symptomatic pathologic compression fractures as supported by high level evidence. The integration of systemic body radiation therapy for spinal metastases has eliminated the need for aggressive tumor resection allowing implementation of MAS epidural tumor decompression via tubular or expandable retractors and preliminary data exist regarding laser interstitial thermal therapy and radiofrequency ablation for tumor control. Neuronavigation and robotic systems offer increased precision, facilitating the role of MAS for spinal metastases.

CONCLUSIONS

MAS has a significant role in the treatment of spinal metastases. This review highlights the current utilization of minimally invasive surgical strategies for treatment of spinal metastases.

Image guidance in spine tumor surgery

Beginning with basic stereotactic operative methods in neurosurgery, intraoperative navigation and image guidance systems have since become the norm in that field. Following the introduction of image guidance into spinal surgery, there has been a dramatic increase in its utilization across disciplines and pathologies. Spine tumor surgery encompasses a wide range of complex surgical techniques and treatment strategies. Similarly to deformity correction and trauma surgery, spine navigation holds potential to improve outcomes and optimize surgical technique for spinal tumors. Recent data demonstrate the applicability of neuro-navigation in the field of spinal oncology, particularly for spinal stabilization, maximizing extent of resection and integration of minimally invasive therapies. The rapid introduction of new, less invasive, and ablative surgical techniques in spine oncology coupled with the rising incidence of spinal metastatic disease make it imperative for spine surgeons to be familiar with the indications for and limitations of imaging guidance. Herein, we provide a practical, current concepts narrative review on the use of spinal navigation in three areas of spinal oncology: (a) extent of tumor resection, (b) spinal column stabilization, and (c) focal ablation techniques.

Mini-open excision of osteoid osteoma using intraoperative O-arm/Stealth navigation

BACKGROUND

Although osteoid osteomas have traditionally been treated by surgical excision, radiofrequency ablation (RFA) has gained favor as a less invasive procedure. However, RFA is contraindicated for osteoid osteomas close to the skin or crucial neurovascular structures, and is not covered by national health insurance in Japan. The aim of the present study was to evaluate the efficacy of surgical excision of osteoid osteomas using intraoperative navigation.

METHODS

We performed a retrospective review of five patients with osteoid osteoma who underwent a mini-open excision using O-arm/Stealth navigation at our institution. The osteoid osteomas were excised using a cannulated cutter or curetted out with the assistance of navigation.

RESULTS

Complete excision was achieved in all patients, which was confirmed by pathological examination. The mean skin incision was 2.1 cm (range, 1.5 to 3.0 cm) and the mean duration required for setup three-dimensional image was 15 min (range, 12 to 20 min). Although the mean visual analog scale score was 7 (range, 4 to 8) before surgery, all patients experienced relief from their characteristic pain immediately after surgery, with the mean scores of 2.2 (range, 1 to 3) and 0 at 2 days and 4 weeks after surgery, respectively. There was no intra-operative complication related to the navigation and no recurrence was observed during the mean follow-up period of 25 months (range, 13 to 33 months).

CONCLUSIONS

Mini-open excision using intraoperative O-arm/Stealth navigation is a safe and accurate procedure for patients with osteoid osteoma, which could cover the limitation of RFA.

Motion preservation surgery: excision of juxta C5-C6 intervertebral disc osteoid osteoma using 3D C-arm based navigation: technical report

INTRODUCTION

Precise targeted excision of the C5-C6 osteoid osteoma with placement of reference array on clavicle with minimal disturbance of anatomy and motion.

METHODS

A 20-year-old male presented with an osteoid osteoma in the superior end plate of the C6 vertebra abutting the spinal canal causing intractable pain. The authors curetted the nidus using a 3D C-arm-based intraoperative scan integrated with an optical navigation system through a minimal access anterior cervical exposure. The patient reference array was affixed to the left clavicle using a threaded pin.

RESULTS

The postoperative CT-scan revealed complete excision. Follow-up MRI and CT after 12 months revealed C5-C6 intervertebral disc to be intact without evidence of any tumor recurrence. VAS for neck pain improved from 8/10 to 2/10 immediately postoperatively and 0/10 at 1 year follow-up with no limitation of cervical movement. A motion segment was preserved with this technique.

CONCLUSIONS

Navigation allowed safe curettage of the nidus with minimal disturbance to the anatomy and motion. The site of attachment of patient reference array on clavicle can be recommended as stable, meeting all the criteria for optimal accuracy and stability.

Percutaneous excision of difficult osteoid osteomas using intraoperative AIRO CT navigation: a preliminary report

Osteoid osteomas are well known for intraoperative technical difficulties for localization and adequate excision, especially when they are not clearly visualized on plain radiographs or when they occur in difficult and inaccessible situations. Localization in the radiology suite and shifting the patient to the operating room can be cumbersome, and can result in errors because of lack of real-time imaging. In these scenarios, intraoperative navigation will be useful. We report a technique of intraoperative computed tomography (CT) navigation for localization and excision of osteoid osteomas of the long bones. Six patients (four femoral and two tibial lesions) with a radiological diagnosis of osteoid osteoma, in whom the nidus could not be visualized clearly on plain radiographs, were treated with this technique. Intraoperative CT navigation with AIRO was performed and the images were registered to the computer. The lesion was then localized and excised using a high-speed burr. All patients underwent postexcision on-table CT scans, which showed complete excision of the nidus. All patients became symptom free and are doing well at a minimum follow-up of 6 months. Intraoperative CT navigation helps to exactly localize the nidus and also helps to confirm complete excision of the nidus. This is a safe, effective and minimally invasive method to treat osteoid osteomas, particularly those that are not amenable to excision under C arm guidance.

Present role and future perspectives of interventional radiology in the treatment of painful bone lesions

Interventional radiology has experienced an exponential growth in the last years. Nowadays it is possible to treat painful benign lesions or metastases with optimal results in terms of pain management and disease control. Among the benign lesions, osteoid osteoma is the most frequently treated with minimal invasive techniques and the results are excellent. Another lesion, traditionally treated with surgery (osteoblastoma) represent today another field of application. In the oncological field, metastases are, numerically, the most diffuse indications for treatment. Research carried out during the last decades has provided the interventional radiologist with a great variety of techniques of ablation and devices for monitoring the sensitive structures close to the target lesion. New ablation techniques and monitoring devices contribute to the achievement of significantly increasing rates of effectiveness and safety of interventional radiology procedures.

Open Surgery for Osteoid Osteoma with Three Dimensional C-arm Scan under the Guidance of Computer Navigation

OBJECTIVE

To evaluate the clinical outcomes of open surgery for osteoid osteoma with three-dimensional (3-D) C-arm scan under the guidance of computer navigation.

METHODS

The clinical data of 14 patients who had undergone 3-D C-arm scan under the guidance of computer navigation during open surgery for osteoid osteoma from March 2012 to June 2015 were analyzed retrospectively. There were nine male and five female subjects aged from 9 to 55 years (mean, 26 years). Eight of the tumors were located in the femur, four in the tibia, one in the humerus and one in the scapula. Preoperative pain visual analogue scale (VAS) scores ranged from 2 to 6 (mean ± SD, 4.7 ± 1.1). Conventional surgical approaches were used to expose the tumor surfaces depending on their locations. Involved regions were scanned by 3-D C-arm fluoroscopy during the procedure and then the tumors were accurately located and their niduses removed under the guidance of computer navigation. Afterwards, repeat 3-D C-arm scans of the surgical region were performed to confirm tumor eradication. None of the patients received postoperative intravenous analgesia. Eight patients received oral non-steroidal anti-inflammatory drugs on the day of surgery, these drugs being discontinued on the second postoperative day. Postoperative pathological diagnoses were recorded. At the follow-up visits, imaging and VAS scores were obtained to evaluate the therapeutic effect and any evidence of recurrence.

RESULTS

All the patients successfully underwent computer navigation-guided surgery. The duration of surgery ranged from 60 to 135 min (mean, 94 min) and the amount of bleeding from 50 to 150 mL (mean, 80 mL). None of the patients needed bone grafting or internal fixation. No complications were seen. All patients were followed up for 4 to 36 months (mean, 16 months). Postoperative pathological diagnoses of osteoid osteoma were made in 12 patients; thus, the rate of pathologically confirmed diagnosis was 86%. VAS scores decrease to an average of 1.4 ± 0.6 3 days after surgery and were zero for all patients 4 months after surgery. No tumor recurrence was found by X-ray or CT scan examination during follow-up.

CONCLUSIONS

The niduses of osteoid osteomas can be eradicated by open surgery with 3-D C-arm scan under the guidance of computer navigation with minimal damage to bone structure and a high rate of pathologically confirmed diagnoses.