Full-endoscopic pedicle-based approach for resection of osteoid osteoma in the lumbar spine: a case report and review of current literature

Abstract

Background

Osteoid osteoma (OO) of the spine is a rare benign tumor that can cause significant pain and radiculopathy, particularly when the lesion involves the posterior elements such as the pedicle. Although traditional treatments like radiofrequency ablation (RFA) and open surgery are effective, they pose risks including neural injury and spinal instability. In recent years, full-endoscopic spine surgery has emerged as a minimally invasive alternative, offering precise lesion localization and resection while preserving spinal integrity.

Case Description

We present the case of a 20-year-old female who reported a 6-month history of progressive low back pain and severe left-sided L5 radiculopathy. Imaging revealed a nidus in the left L5 pedicle consistent with OO. The lesion was successfully resected using a full-endoscopic pedicle-based approach with the RIWOspine system. The procedure was performed under fluoroscopic guidance, allowing direct visualization and excision of the nidus. The patient experienced immediate symptom relief, and postoperative imaging confirmed complete resection. Histopathological examination confirmed the diagnosis of OO. At 1-year follow-up, she remained asymptomatic with no evidence of recurrence or spinal instability.

Conclusions

Full-endoscopic pedicle-based resection provides a safe, effective, and minimally invasive technique for managing spinal OOs. This approach offers direct nidus visualization, preservation of spinal stability, and excellent clinical outcomes, supporting its utility as a preferred option in select cases. A literature review further supports its utility as a viable first-line surgical option, particularly in young patients with posterior element lesions. Future studies are needed to validate this technique in larger cohorts and to establish standardized protocols.

Highlight box.

Key findings

• This case report describes the successful application of a full-endoscopic pedicle-based approach for the resection of an osteoid osteoma (OO) located in the left L5 pedicle.

• The patient experienced immediate and sustained relief from severe radiculopathy, with postoperative imaging confirming complete nidus excision and no evidence of recurrence.

• A comprehensive literature review supports the efficacy and safety of endoscopic spinal techniques, particularly in the management of OO involving posterior spinal elements.

What is known and what is new?

• OO of the spine, though rare, presents significant clinical challenges due to its proximity to neural structures. Traditional management includes open resection or radiofrequency ablation, both associated with limitations such as iatrogenic instability or thermal injury.

• This report highlights the feasibility and clinical advantages of a full-endoscopic pedicle-based technique, which enables precise, minimally invasive nidus removal with preservation of spinal stability. To date, few studies have reported the use of this approach specifically for lesions located in the pedicle.

What is the implication, and what should change now?

• The favorable outcome observed in this case, supported by a review of the current literature, suggests that the full-endoscopic pedicle-based approach should be considered a viable first-line surgical option for spinal OOs, particularly in young patients.

• Incorporation of this technique into clinical practice may reduce operative morbidity, facilitate faster postoperative recovery, and obviate the need for extensive decompression or fusion procedures.

• Further prospective studies are warranted to standardize indications, refine technique-specific protocols, and validate long-term outcomes in larger patient cohorts.

Introduction

Osteoid osteoma (OO) is a benign osteogenic tumor that accounts for approximately 10% of all benign bone tumors. While it predominantly affects the long bones of the lower extremities, spinal involvement occurs in about 10–20% of cases, with the lumbar spine being the most commonly affected region. Within the spine, the posterior elements, particularly the pedicles and laminae, are frequently involved. Clinically, spinal OO often presents with localized pain that intensifies at night and is typically relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). When the lesion is situated near neural structures, patients may experience radiculopathy or other neurological symptoms. Conservative management with NSAIDs is effective in many cases; however, surgical intervention becomes necessary when symptoms persist or worsen (1,2). Traditional surgical approaches, such as open resection or radiofrequency ablation (RFA), have been employed to treat spinal OO (3,4). However, these methods carry risks, including spinal instability, damage to surrounding tissues, and incomplete removal of the nidus (5). In recent years, minimally invasive techniques, particularly full-endoscopic spine surgery, have emerged as effective alternatives, offering the advantages of reduced tissue disruption, direct visualization of the lesion, and preservation of spinal stability (6). In this report, we present the case of a 20-year-old female with an OO located in the left L5 pedicle, who was successfully treated using a full-endoscopic pedicle-based approach. We also provide a comprehensive review of the current literature on endoscopic management of spinal OO, highlighting the efficacy and safety of this minimally invasive technique. We present this article in accordance with the CARE reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-25-59/rc) (7).

Case presentation

A 20-year-old female without underlying disease presented with a 6-month history of progressive low back pain accompanied by severe radiculopathy radiating to the left lower limb in the L5 distribution. The pain was worse at night and partially relieved by NSAIDs. Neurological examination was unremarkable except for a positive straight leg raise test on the left side. Plain radiographs were inconclusive. Computed tomography (CT) revealed a well-defined radiolucent nidus with surrounding sclerosis located in the left L5 pedicle (Figure 1A-1B). Magnetic resonance imaging (MRI) demonstrated adjacent bone marrow edema and without impingement on the left L5 nerve root (Figure 1C,1D). A diagnosis of spinal OO was made. A full-endoscopic resection via a pedicle-based approach was performed using the RIWOspine endoscopic system (RIWOspine GmbH, Knittlingen, Germany). Under general anesthesia, the patient was positioned prone, and a pedicle-based working channel was established under biplanar fluoroscopic guidance. After cortical bone drilling, the nidus was directly visualized and excised under continuous endoscopic irrigation. The nidus appeared as a hypervascular reddish lesion embedded within sclerotic bone and was resected completely using a high-speed burr and endoscopic graspers (Figure 2A-2H). Fluoroscopic images confirmed proper trajectory and instrument positioning throughout the procedure (Figure 3A-3H). No intraoperative complications occurred. The patient reported immediate resolution of radicular symptoms and was discharged on the second postoperative day. She resumed normal activities within 2 weeks. Histopathological analysis confirmed the diagnosis of OO, revealing interlacing trabeculae of woven bone rimmed by osteoblasts embedded within a fibrovascular stroma (Figure 4A-4C). At the 3-month and 1-year follow-ups, the patient remained asymptomatic without recurrence of pain or neurologic symptoms. Follow-up CT and MRI confirmed complete nidus removal, resolution of bone marrow edema, and preservation of spinal stability (Figure 5A-5D).

Figure 1.

Preoperative imaging of a 20-year-old female with osteoid osteoma in the left L5 pedicle. (A) Axial CT showing a well-defined radiolucent nidus (red arrow) surrounded by sclerosis in the left L5 pedicle. (B) Sagittal CT confirming the nidus (red arrow) within the posterior aspect of the pedicle. (C) Axial T2-weighted MRI demonstrating adjacent bone marrow edema and inflammatory changes (red arrow). (D) Sagittal T2-weighted MRI revealing signal changes and compression near the left L5 nerve root (red arrow). CT, computed tomography; MRI, magnetic resonance imaging.

Figure 2.

Intraoperative endoscopic views of the full-endoscopic pedicle-based resection of osteoid osteoma using the RIWOspine system. (A) Initial exposure of the L5 pedicle cortical surface. (B,C) Drilling of the cortical bone to access the underlying lesion. (D) Identification of the hypervascular nidus within the cancellous bone. (E) Beginning of nidus resection with visible hemorrhagic changes. (F,G) Progressive resection of the nidus using endoscopic burr and grasper. (H) Final cavity after complete nidus removal and hemostasis, showing preserved margins of the pedicle and clean resection bed.

Figure 3.

Intraoperative fluoroscopic guidance during full-endoscopic pedicle-based resection of osteoid osteoma at the left L5 pedicle. (A) Initial placement of spinal needle to localize the L5 pedicle. (B) AP view showing the docking point of the working cannula. (C) Lateral view confirming trajectory toward the lesion. (D) Placement of the endoscopic working sleeve over the pedicle entry. (E,F) Sequential insertion and adjustment of the endoscopic drill and working instruments under fluoroscopic control. (G) Intraoperative image showing precise targeting of the nidus location. (H) Final positioning during nidus resection, ensuring accurate orientation and safety. AP, anteroposterior.

Figure 4.

Histopathological examination of the resected specimen confirming the diagnosis of osteoid osteoma (H&E stain, ×100). (A) Low magnification showing irregular trabeculae of woven bone lined by osteoblasts embedded in a fibrovascular stroma. (B) Presence of immature osteoid tissue with scattered osteoblasts and vascularized intertrabecular stroma characteristic of the nidus. (C) Higher magnification demonstrating anastomosing bony trabeculae with prominent osteoblastic rimming, typical of osteoid osteoma. H&E, hematoxylin and eosin.

Figure 5.

Postoperative images. (A) Axial CT confirming complete resection of the nidus with preserved pedicle structure (green arrow). (B) Sagittal CT showing no residual lesion post endoscopic resection (green arrow). (C) Axial T2-weighted MRI demonstrating resolution of inflammatory edema and decompression of neural elements (green arrow). (D) Sagittal T2-weighted MRI illustrating normalization of signal and absence of residual tumor or compression (green arrow). CT, computed tomography; MRI, magnetic resonance imaging.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

OO is a benign spinal tumor that often affects the posterior elements, especially in the lumbar spine. While NSAIDs typically relieve symptoms, lesions near neural structures can cause radiculopathy, requiring surgical intervention when pain persists (8,9). Traditional surgical approaches, such as open resection or RFA, have been employed to treat spinal OO. However, these methods carry risks, including spinal instability, damage to surrounding tissues, and incomplete removal of the nidus. In recent years, minimally invasive techniques, particularly full-endoscopic spine surgery, have emerged as effective alternatives, offering the advantages of reduced tissue disruption, direct visualization of the lesion, and preservation of spinal stability (6).

In our case, a 20-year-old female with an OO located in the left L5 pedicle underwent successful full-endoscopic pedicle-based resection using the RIWOspine system. The patient experienced immediate postoperative relief from radicular symptoms and remained asymptomatic at the one-year follow-up, with imaging confirming complete lesion removal and no evidence of recurrence. The literature supports the efficacy and safety of full-endoscopic techniques in managing spinal OO. Previous study, Bergamaschi et al. (10) and Kotheeranurak et al. (11) reported a case where full-endoscopic resection of a lumbar OO resulted in complete symptom resolution and facet joint remodeling over a two-year follow-up period. Similarly, Xie et al. (12) presented a series of 11 patients who underwent percutaneous endoscopic excision and ablation, all of whom experienced significant pain relief without complications or recurrences over an average follow-up of 21.8 months. Liu et al. (6) employed computer-assisted navigation with full visualization endoscopy, resulting in complete resection and significant bone remodeling. A summary of these and other relevant studies is presented in Table 1. These findings underscore the advantages of full-endoscopic resection, including minimal invasiveness, reduced postoperative pain, shorter hospital stays, and preservation of spinal stability. However, the technique requires specialized equipment and a steep learning curve, emphasizing the need for adequate training and experience. In conclusion, full-endoscopic pedicle-based resection represents a safe and effective treatment modality for spinal OO, offering the benefits of minimally invasive surgery without compromising clinical outcomes.

Table 1. Summary of current previous studies focusing on full-endoscopic resection of osteoid osteoma.

Study	Year	Study type	Sample size	Technique	Outcomes	Follow-up
Xie et al. (12)	2020	Case series	11	Percutaneous endoscopic excision and ablation	Significant pain relief; no complications or recurrences	21.8 months
Bergamaschi et al. (10)	2021	Case report	1	Full-endoscopic resection	Immediate pain relief; no recurrence	1 year
Kotheeranurak et al. (11)	2022	Case report	1	Full-endoscopic resection	Symptom-free; facet joint remodeling	2 years
Liu et al. (6)	2023	Case report	1	Computer-assisted navigation with full visualization endoscopy	Successful resection; significant bone remodeling; no recurrence	1 year
Our study	2025	Case report	1	Full-endoscopic transpedicular approach	Successful resection; significant bone remodeling; no recurrence	1 year

In the future, navigation-assisted endoscopy may serve as a valuable adjunct in spinal procedures, particularly for lesions situated in anatomically challenging areas such as the inferolateral aspect of the pedicle. The use of intraoperative three-dimensional (3D) navigation or CT-guided endoscopy could enhance surgical accuracy by providing real-time visualization of the trajectory relative to the nidus. Incorporating these advanced imaging technologies in future cases may improve the precision of endoscopic resections, minimize the risk of incomplete lesion removal, and ultimately lead to better clinical outcomes. Further studies with larger sample sizes and longer follow-up periods are warranted to establish standardized protocols and to further validate the long-term efficacy of this approach (Table 1).

Conclusions

Full-endoscopic pedicle-based resection is a safe, effective, and minimally invasive technique for the treatment of OO in the lumbar spine. This approach enables direct visualization and precise excision of the nidus while preserving surrounding anatomical structures and minimizing patient morbidity. Our case, along with the current literature, supports its use as a viable alternative to traditional open surgery or RFA, particularly in young patients where spinal integrity and rapid recovery are paramount. With appropriate surgical expertise and careful preoperative planning, full-endoscopic techniques should be considered part of the standard armamentarium for spinal OO management.

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.