Abstract
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.
Introduction
Osteoid osteoma (OO) was first described by Jaffe in 1935 as a benign osteoblastic bone tumor with a diameter of less than 1 cm. 1 OOs comprise 10% of all benign bone tumors. 2 The tibia and femur are involved in 50% of the lesions, and most commonly in the proximal femur.3,4 The incidence of OO in the upper limb is reported to be 15%–31%.5,6 Young males under the age of 40 years are 2 to 3 times more likely than females to be affected, and some studies report that 67%–80% of OOs occur in individuals younger than 25 years of age.1,6–8
Aching discomfort is the most common initial symptom. It is usually worse at night and can be alleviated by rest, heat, or non-steroidal anti-inflammatory drugs (NSAIDs). OOs located near a joint can cause joint dysfunction, reactive synovitis, and effusion, which can present with stiffness and restrictions in daily activities. 6 Prostaglandin E2 is produced at the center of the nidus, which may explain the cause of the pain,9,10 as well as the responsiveness to NSAIDs, which reportedly relieve the discomfort in 64%–88% of cases.4,11
Imaging modalities used for the identification and diagnosis of OOs include radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) studies. Approximately 25%–40% of OOs are not visualized on conventional radiographs, necessitating CT imaging to diagnose them.4,12 A recent systematic review demonstrated that CT was the most sensitive (96.4%) imaging modality for identifying OOs, followed by plain radiography (66.4%) and MRI (65.3%). 13
An OO is self-limiting, and regression time of non-treated OOs is reported to be 6–15 years. 14 Surgical intervention is indicated when non-operative treatment fails, and the various options include radiofrequency ablation (RFA), laser thermocoagulation, arthroscopic excision, en bloc resection with excision of the entire lesion and the surrounding reactive zone, excisional biopsy, open curettage and ethanol application. En bloc excision and radiofrequency ablation are the 2 most frequently used techniques (36.9% and 25.6% respectively). 13 CT-guided ablation, navigation technologies, fluoroscopy, and arthroscopy have been reported as means to accurately locate the lesion during the procedure to target treatment.13,15–17 Locating the nidus during open operation or minimally invasive RFA in the upper extremity, however, is highly challenging. The proximity of sensitive anatomic structures, such as joints, skin, tendons, nerves, and blood vessels, makes it critically important to accurately locate and excise the lesion with minimal dissection and collateral damage.
The purpose of this study is to present the preoperative characteristics, the operative technique, and the postoperative outcomes of all patients with OO of the upper extremity who were treated in our institution since 2015 when we began using O arm navigation to guide accurate surgical treatment of the lesion. The guided surgical technique included either percutaneous RFA or mini open curettage. The choice between the two techniques was made by the surgeon according tothe location of the OO and the proximity to neurovascular structures, the skin, or tendons.
Materials and methods
Study design and data collection
This is a retrospective case series study. Following institutional review board approval, we identified all patients with OO of the upper extremity who underwent surgical treatment in our medical center between 1.1.2015-1.6.2022. Demographic data, date of surgery, preoperative symptoms, OO location and size, QuickDASH 18 (disabilities of the arm, shoulder, and hand) score before and after surgery, physical examination findings, and complications were collected from electronic records and imaging studies.
Outpatient clinic follow up
All the study patients had been diagnosed and followed in the outpatient clinic prior to undergoing surgery. Non operative treatment options included analgesics and NSAIDS. The indications to proceed with surgical intervention included substantial pain lasting for more than 3 months with failure of non-operative treatment, as well as radiologic confirmation of a nidus. They all underwent CTs and some also underwent radiographs and MRIs. In some patients with radiographic or CT findings of OO, an MRI was performed to evaluate the location of neurovascular structures around the lesion. Some patients underwent an MRI as part of the diagnostic workup prior to OO diagnosis. The postoperative routine clinic follow-up took place at 2, 6, and 12 weeks, followed by 6 and 12 months and yearly thereafter.
Surgical procedure
All operations were performed by a single surgeon according to a technique published by Ankory et al in 2019 and later by Gurel et al in 2022.15,19 The patient was placed on a radiolucent, fluoroscopy-capable operating table, and the affected limb was prepared and draped in a sterile manner. The optical tracking array was secured to the patient either by silk sutures to the skin in proximity to the lesion or by bony anchor devices, depending upon the anatomical location of the lesion. The optical tracking array is the instrument which maintains accuracy of the navigation following the scan, even if the surgical site moves. The site was then scanned by a cone beam CT (O-arm® scanner Medtronic Sofamor, Danek Memphis, TN, USA) to locate the lesion. A 3-dimensional image was created by the navigation system (StealthStation®, Medtronic Sofamor) and by a set of calibrated navigational instruments (mainly a drill bit or a Jamshidi needle), after which the bone and the lesion were penetrated by means of real-time navigation. Specimens from the lesion were sent for histological analysis. When RFA was used, the specimens were obtained prior to placement of the RFA needle. When there was no contraindication to the use of RFA, a 15-cm RF probe needle (RITA Angiodynamics Inc., USA or Covidien Ltd. USA, cool tip 15 cm-long) was then advanced without any additional fluoroscopy images or scans. When the needle came in contact with the lesion, a second scan was performed to verify the location of the needle tip, and the ablation was performed according to a protocol of 90°C for 6–9 min. Lastly, the skin was sutured with 3-0 nylon sutures, and the patient’s skin was examined for burns or other superficial complications. When the lesion was in proximity to the skin, tendons, joints, or neurovascular structures and when RFA was contraindicated, navigation was used to accurately identify the location of the nidus and to safely remove it completely by curettage with a high-speed burr. The choice between navigated curettage or navigated RFA was made by the surgeon, taking into account the location of the lesion, the possibility to reach it by using an open approach, its proximity to the skin, tendons and neurovascular structures. In some of the cases, even when the lesion was near such structures RFA was still used and the relevant structures were protected by retraction which placed them under vision and away from the RFA destruction zone. Figures 1 and 2 show examples of navigated RFA and mini open procedures. Radiographs, CT scan, T2 sequence MRI and pre/post navigated mini open intralesional curettage O-arm scan of osteoid osteoma of the distal humerus (patient No. 10). Radiographs, CT scan MRI and pre/post navigated minimally invasive radiofrequency ablation O-arm scans of osteoid osteoma of the capitate (patient No. 14).
Statistical analysis
Continuous data are presented as mean ± standard deviation, and categorical data are presented as percentage. A paired sample t test was applied to compare preoperative to postoperative QuickDASH score. A p-value of .05 or lower was considered statistically significant. All analyses were performed by IBM SPSS v24.
Results
Patient characteristics outcomes and complications.
The preoperative and last follow-up postoperative average QuickDASH scores were 62.2 ± 23.7 and 11.7 ± 16.9, respectively (p < .01). The preoperative and last follow-up postoperative average NPRS scores were 8.1 ± 1.6 and 0.5 ± 1.8, respectively (p < .01). Seventeen out of the 19 study patients reported substantial subjective functional improvement and complete or almost complete (0-1 on NPRS) pain resolution following the procedure. Three of them required a second procedure to achieve resolution of symptoms. One patient had neither pain nor functional improvement following her surgery (patient #4). She underwent a second arthroscopic surgery 6 months following her first operation which also did not improve her symptoms. This patient had marked arthritic elbow changes before the primary procedure which may account for the failure of the procedure. Another patient (patient #7) had complete resolution of her OO-related symptoms, but she sustained complete persistent radial palsy following navigated minimally invasive radio frequency ablation (NMRFA). Following Navigatied mini open intra lesional curettage (NMIC), patient #10 had complete resolution of his OO-related symptoms, although he sustained transient partial radial nerve weakness which completely resolved.
Imaging results.
Discussion
The findings of our study demonstrate favorable results for the use of navigated RFA/curettage for treating OO of the upper extremity. The characteristics of our patients were similar to those of patients described in other publications on OO of the upper extremity.20,21 We observed functional improvement of the patients following surgery, which was also demonstrated by a significant reduction in their average NPRS and QuickDASH scores. Our reoperation rate was similar to the limited data available in current literature.20–22 In our series, 3 patients had persistence of symptoms following primary NMRFA. They all underwent Re-NMRFA which resulted in resolution of their symptoms. One patient with persistent pain accompanied by limited elbow range of motion and notable radiographic arthritic symptoms underwent arthroscopic revision surgery which failed. We encountered 2 neurologic complications: one patient had persistent radial nerve palsy at the level of the distal humerus and another patient had transient radial nerve weakness which completely resolved.
In this publication, as in two earlier publications on the application of our surgical method in multiple locations, we present our navigated approach to osteoid osteoma.15,19 The navigated technique offered improved accuracy and provided measures to confirm the removal of the lesion during the procedure. It also allowed operation room and surgical team setting which enables an open or mini open approach with dissection and protection of neurovascular structures. The navigated technique for the treatment of osteoid osteoma has been described in several publications in addition to ours,15,19,23–25 and this is the first that is specific to the upper extremity. In a study by Ankory et al, our surgical technique was first described and published. 15 We demonstrated the results of the first 52 patients who underwent navigated radiofrequency ablations for the treatment of OO in our institution. Another publication by Gurel et al presented the results of 14 patients with OO of the foot and ankle and also discussed the added value of the navigated technique in mini open curettage and complex anatomic locations. 19
Although CT guidance in ablation procedures of OO is a well-accepted and accurate method,16,26–29 the navigated technique offers a more flexible real-time stepwise approach to the exact location of the nidus in comparison to the CT-guided technique in which multiple scans may sometimes be required until an accurate location is found and during which the surgical instruments may harm nearby structures. It also enables less radiation exposure to the surgical team. 15 Finally, all of our reported procedures were performed by an orthopedic surgeon in an operating room setting, which enabled both closed manipulation for stiff joints as well as an additional open approach in some of the patients treated with NMRFA (patients 1, 2, 7, 9, 15, 17, 19) for the retraction of neurovascular structures away from the “destruction zone” of the RFA needle, when necessary, thereby increasing the safety of the procedure and enabling the performance of minimally invasive RFA in cases which otherwise would have required open curettage.
Intralesional curettage was performed when the RFA approach was contraindicated due to the location of the OO being in close proximity to the skin, tendons, or neurovascular structures. We consider navigation to also be indicated in open or arthroscopic surgery since one of the major challenges in any surgical treatment of OO is posed by the difficulty of identifying and confirming complete removal of the nidus. 24
Four of the OO cases in this series involved the elbow joint. All 4 were associated with synovial joint reaction and limited range of motion. Three of those patients had complete resolution of their symptoms following the primary operation. One patient underwent secondary arthroscopic surgery which did not improve her symptoms. A closed manipulation to increase the range of motion was performed during the procedures of these patients with OO involving the elbow joint associated with limited range of motion. Performing the manipulation to address the elbow stiffness was possible thanks to the setting of an operation room, general anesthesia, and orthopedic surgeon who performed the procedure. There are several publications of surgical outcomes of OO involving the elbow. Kamrani et al reported the results of 10 such patients who underwent arthroscopic ablation. Those authors observed improved function and resolution of OO-related symptoms in those patients. Two of their patients underwent reoperation, one of whom patients had subsequent arthrosis and the other had persistent pain. 21 Knežević et al published their series (6 patients) and a review of the literature (23 patients) on OO involving the elbow with success rates of 86.4%–96.3%, minimal complication rates, and recurrence rates of 0%–3.7%. 30 Ge et al also published a review of 19 patients with OO of the elbow who underwent arthroscopic treatment. They reported good functional outcomes with 10.5% reoperations and 10.5% complications. 22
The first attempt of NMRFA did not solve the OO symptoms and a second Re- NMRFA was successful in 3 of our current cases. We believe that when the first procedure is unsuccessful, unless there is a specific reason to consider a different surgical technique, the revision surgery can also be NMRFA. All re-NMRFAs performed in these series achieved resolution of the OO symptoms. We attribute the failure in the primary procedures to an incomplete ablation of the lesion and therefore think that although the first attempt was unsuccessful, the chances are high for success in a repeated attempt and a benefit of NMRFA over open surgery. Our revision rate was similar to those of other publications.20–22,28
We encountered 2 peripheral nerve injuries in this series. Patient #10 had partial transient radial nerve neuropraxia which completely resolved, leaving this patient symptom free with excellent functional outcome. Although patient #7 had complete resolution of her OO-related symptoms, she also had persistent radial nerve palsy at the level of the distal humerus. We attribute this peripheral nerve injury to thermal injury sustained by the RFA. After the occurrence of this complication, we adopted a much more liberal approach in performing an open or mini-open approach prior to placement of the RFA needle in order to ensure safe distance of the needle from any neurovascular structure.
The main limitation of our study is its retrospective design and the lack of a control group. Other publications on OO in the upper extremity commonly share those drawbacks.
In conclusion, our study findings demonstrate good results for navigated operative treatment of OO of the upper extremity. Only one of our 19 patients had no resolution of OO-related symptoms, while one patient had persistent radial nerve palsy. We demonstrated that the navigated technique provided definitive assistance in performing curative surgery for OO in the challenging anatomy of the upper limb.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
