Aims. The purpose of this study was to assess the success rate and functional outcomes of bone grafting for periprosthetic bone cysts following total ankle arthroplasty (TAA). Additionally, we evaluated the rate of graft incorporation and identified associated predisposing factors using CT scan. Methods. We reviewed a total of 37 ankles (34 patients) that had undergone bone grafting for periprosthetic bone cysts. A CT scan was performed one year after bone grafting to check the status of graft incorporation. For accurate analysis of cyst volumes and their postoperative changes, 3D-reconstructed CT scan processed with 3D software was used. For functional outcomes, variables such as the Ankle Osteoarthritis Scale score and the visual analogue scale for pain were measured. Results. Out of 37 ankles, graft incorporation was successful in 30 cases. Among the remaining seven cases, four (10.8%) exhibited cyst re-progression, so secondary bone grafting was needed. After secondary bone grafting, no further progression has been noted, resulting in an overall 91.9% success rate (34 of 37) at a mean follow-up period of 47.5 months (24 to 120). The remaining three cases (8.1%) showed implant loosening, so tibiotalocalcaneal arthrodesis was performed. Functional outcomes were also improved after bone grafting in all variables at the latest follow-up (p < 0.05). The mean incorporation rate of the grafts according to the location of the cysts was 84.8% (55.2% to 96.1%) at the medial malleolus, 65.1% (27.6% to 97.1%) at the tibia, and 81.2% (42.8% to 98.7%) at the talus. Smoking was identified as a significant predisposing factor adversely affecting graft incorporation (p = 0.001). Conclusion. Bone grafting for periprosthetic bone cysts following primary TAA is a reliable procedure with a satisfactory success rate and functional outcomes. Regular follow-up, including CT scan, is important for the detection of cyst re-progression to prevent implant loosening after bone grafting. Cite this article: Bone Joint J 2024;106-B(5):475–481

Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation. Materials & Methods. Case 1 - A 12-year-old boy presented with a two-week history of atraumatic right ankle pain. An X-ray demonstrated a distal tibia metaphyseal cyst confirmed on biopsy as an aneurysmal bone cyst. The cyst expanded on interval X-rays from 5.5cm to 8.5cm in 9 weeks. A wide-margin en-bloc resection was performed leaving a 13.8cm tibial defect. A cable transport hexapod frame and a proximal tibial osteotomy was performed, with syndesmosis screw fixation. The transport phase lasted 11 months. While in frame, the boy sustained a distal femur fracture from a fall. The femur and the docking site were plated at the same sitting and frame removed. At one-year post-frame removal he is pain-free, with full ankle dorsiflexion but plantarflexion limited to 25 degrees. He has begun graduated return to sport. Results. Case 2 - A 12-year-old girl was referred with a three-month history of lateral left ankle swelling. X-ray demonstrated an aneurysmal bone cyst in the distal fibula metaphysis. The cyst grew from 4.2 × 2.3cm to 5.2 × 3.32cm in 2 months. A distal fibula resection (6.2cm) with syndesmosis fixation and hexapod cable transport frame were undertaken. The frame was in situ for 13 weeks and during this time she required an additional osteotomy for premature consolidation and had one pin site infection. After 13 weeks a second syndesmosis screw was placed, frame removed, and a cast applied. 3 months later she had fibular plating, BMAC and autologous iliac crest bone graft for slow union. At 3 years post-operative she has no evidence of recurrence, is pain-free and has no functional limitation. Conclusions. We describe two cases of ankle syndesmosis preservation using cable transport for juxta-articular aneurysmal bone cysts. This allows wide resection to prevent recurrence while also preserving primary ankle stability and leg length in children. Both children had a minor complication, but both had an excellent final outcome. Cable bone transport and prophylactic syndesmosis stabilization allows treatment of challenging juxta-articular aneurysmal bone cysts about the ankle. These techniques are especially useful in large bone defects

Aims. The aim of this study is to evaluate the surgical treatment with the best healing rate for patients with proximal femoral unicameral bone cysts (UBCs) after initial surgery, and to determine which procedure has the lowest adverse event burden during follow-up. Methods. This multicentre retrospective study was conducted in 20 tertiary paediatric hospitals in France, Belgium, and Switzerland, and included patients aged < 16 years admitted for UBC treatment in the proximal femur from January 1995 to December 2017. UBCs were divided into seven groups based on the index treatment, which included elastic stable intramedullary nail (ESIN) insertion with or without percutaneous injection or grafting, percutaneous injection alone, curettage and grafting alone, and insertion of other orthopaedic hardware with or without curettage. Results. A total of 201 patients were included in the study. The mean age at diagnosis was 8.7 years (SD 3.9); 77% (n = 156) were male. The mean follow-up was 9.4 years (SD 3.9). ESIN insertion without complementary procedure had a 67% UBC healing rate after the first operation (vs 30% with percutaneous injection alone (p = 0.027), 43% with curettage and grafting (p = 0.064), and 21% with insertion of other hardware combined with curettage (p < 0.001) or 36% alone (p = 0.014)). ESIN insertion with percutaneous injection presented a 79% healing rate, higher than percutaneous injection alone (p = 0.017), curettage and grafting (p = 0.028), and insertion of other hardware combined with curettage (p < 0.001) or alone (p = 0.014). Patients who underwent ESIN insertion with curettage had a 53% healing rate, higher than insertion of other hardware combined with curettage (p = 0.009). The overall rate of postoperative complications was 25% and did not differ between groups (p = 0.228). A total of 32 limb length discrepancies were identified. Conclusion. ESIN insertion, either alone or combined with percutaneous injection or curettage and grafting, may offer higher healing rates than other operative procedures. Limb length discrepancy remains a major concern, and might be partly explained by the cyst’s location and the consequence of surgery. Therefore, providing information about this risk is crucial. Cite this article: Bone Joint J 2024;106-B(5):508–514

Aims. The aim of this study was to analyze the complications and outcomes of treatment in a series of previously untreated patients with a primary aneurysmal bone cyst (ABC) who had been treated by percutaneous sclerosant therapy using polidocanol. Methods. Between January 2010 and December 2016, 56 patients were treated primarily with serial intralesional sclerosant injections. Their mean age was 20 years (1 to 54). The sites involved were clavicle (n = 3), humeri (n = 11), radius (n = 1), ulna (n = 3), hand (n = 2), pelvis (n = 12), femur (n = 7), tibia (n = 13), fibula (n = 3), and foot (n = 1). After histopathological confirmation of the diagnosis, 3% polidocanol (hydroxypolyaethoxydodecan) was injected into the lesion under image intensifier guidance. Patients were evaluated clinically and radiologically every six to eight weeks. In the absence of clinical and/or radiological response, a repeat sclerosant injection was given after eight to 12 weeks and repeated at similar intervals if necessary. Results. There were no complications of treatment. One patient was lost to follow-up. Overall, 46/55 (84%) of lesions healed after one or more injections of polidocanol: 24/55 (44%) patients healed with a single injection, and 43/55 (78%) within two injections. Of these 46, four (9%) patients developed local recurrence, two of whom healed with a repeat sclerosant injection. Thus, 44/55 (80%) patients of primary ABC healed with sclerotherapy. The mean follow-up was 62 months (20 to 111). The local recurrence free survival (LRFS) with percutaneous sclerosant therapy with polidocanol was 100%, 98% (95% confidence interval (CI) 85 to 100) and 93% (95% CI 78 to 98) at two, three, and five years, respectively. Conclusion. Percutaneous sclerotherapy using polidocanol is a safe, effective, minimally invasive and inexpensive method of treating a primary ABC of the limbs or pelvis. Cite this article: Bone Joint J 2020;102-B(2):186–190

Open surgery is rarely justified for the initial treatment of a unicameral bone cyst, but there is some debate concerning the relative effectiveness of closed methods. This study compared the results of steroid injection with those of autologous bone marrow grafting for the treatment of unicameral bone cysts. Between 1990 and 2001, 30 patients were treated by steroid injection and 28 by grafting with autologous bone marrow. The overall success rates were 86.7% and 92.0%, respectively (p > 0.05). The success rate after the initial procedure was 23.3% in the steroid group and 52.0% in those receiving autologous bone marrow (p < 0.05), and the respective cumulative success rates after second injections were 63.3% and 80.0% (p > 0.05). The mean number of procedures required was 2.19 (1 to 5) and 1.57 (1 to 3) (p < 0.05), the mean interval to healing was 12.5 months (4 to 32) and 14.3 months (7 to 36) (p > 0.05), and the rate of recurrence after the initial procedure was 41.7% and 13.3% in the steroid and in the autologous bone marrow groups, respectively (p < 0.05). Although the overall rates of success of both methods were similar, the steroid group had higher recurrence after a single procedure and required more injections to achieve healing

Aneurysmal bone cyst (ABC) of the spine is a locally aggressive benign lesion which can be treated by en bloc resection with wide margin to reduce the risk of local recurrence. To avoid morbidity associated with surgery, selective arterial embolization (SAE) can be considered the first-line treatment for ABCs of the spine. We previously introduced the use of autologous bone marrow concentrate (BMC) injection therapy to stimulate bone healing and regeneration in ABC of the spine. In this prospective study we described the clinical and radiological outcomes of percutaneous injection of autologous BMC in a series of patients affected by ABCs of the spine. Fourteen patients (6 male, 8 female) were treated between June 2014 and December 2019 with BMC injection for ABC of the spine. The mean age was 17.85 years. The mean follow up was 37.4 months (range 12–60 months). The dimension of the cyst and the degree of ossification were measured by Computed Tomography (CT) scans before the treatment and during follow-up visits. Six patients received a single dose of BMC, five patients received two doses and in three patients three doses of BMC were administered. The mean ossification of the cyst (expressed in Hounsfield units) increased statistically from 43.48±2.36 HU to 161.71±23.48 HU during follow-up time and the ossification was associated to an improvement of the clinical outcomes. The mean ossification over time was significantly higher in patients treated with a single injection compared to patients treated with multiple injections. No significant difference in ossification was found between cervical and non-cervical localization of the cyst. Moreover, the initial size of the cyst was not statistically associated with the degree of ossification during follow-up. The results of this study reinforce our previous evidence on the use of BMC as a valid alternative for spinal ABC management when SAE is contraindicated or ineffective. The initial size of the cyst and its localization does not influence the efficacy of the treatment. However, data suggest that BMC injection could be indicated as treatment of choice for spinal ABC in young adolescent women

Aneurysmal bone cyst is a rare tumour-like lesion which develops during growth. Our aim was to determine the efficacy of the administration of percutaneous intralesional 3% polidocanol (hydroxypolyaethoxydodecan) as sclerotherapy. Between July 1997 and December 2004 we treated 72 patients (46 males, 26 females) with a histologically-proven diagnosis of aneurysmal bone cyst, at various skeletal sites using this method. The sclerotherapy was performed under fluoroscopic guidance and general anaesthesia or sedation and local anaesthesia. The mean follow-up period was 34 months (26.5 to 80). The patients were evaluated using the Enneking system for functional assessment and all the lesions were radiologically quantified into four grades. The mean age of patients was 15.6 years (3 to 38) and the mean number of injections was three (1 to 5). Ten patients were cured by a single injection. The mean reduction in size of the lesion (radiological healing) was found to be 76.6% (61.9% to 93.2%) with a mean clinical response of 84.5% (73.4% to 100%). Recurrence was seen in two patients (2.8%) within two years of treatment and both were treated successfully by further sclerotherapy. Percutaneous sclerotherapy with polidocanol is a safe alternative to conventional surgery for the treatment of an aneurysmal bone cyst. It can be used at surgically-inaccessible sites and treatment can be performed on an out-patient basis

Aims. Aneurysmal bone cysts (ABCs) are locally aggressive lesions typically found in the long bones of children and adolescents. A variety of management strategies have been reported to be effective in the treatment of these lesions. The purpose of this review was to assess the effectiveness of current strategies for the management of primary ABCs of the long bones. Methods. A systematic review of the published literature was performed to identify all articles relating to the management of primary ABCs. Studies required a minimum 12-month follow-up and case series reporting on under ten participants were not included. Results. A total of 28 articles meeting the eligibility criteria were included in this review, and all but one were retrospective in design. Due to heterogeneity in study design, treatment, and outcome reporting, data synthesis and group comparison was not possible. The most common treatment option reported on was surgical curettage with or without a form of adjuvant therapy, followed by injection-based therapies. Of the 594 patients treated with curettage across 17 studies, 86 (14.4%) failed to heal or experienced a recurrence. Similar outcomes were reported for 57 (14.70%) of the 387 patients treated with injection therapy across 12 studies. Only one study directly compared curettage with injection therapy (polidocanol), randomizing 94 patients into both treatment groups. This study was at risk of bias and provided low-quality evidence of a lack of difference between the two interventions, reporting success rates of 93.3% and 84.8% for injection and surgical treatment groups, respectively. Conclusion. While both surgery and sclerotherapy are widely implemented for treatment of ABCs, there is currently no good quality evidence to support the use of one option over the other. There is a need for prospective multicentre randomized controlled trials (RCTs) on interventions for the treatment of ABCs. Cite this article: Bone Jt Open 2021;2(2):125–133

1. Three cases of aneurysmal bone cyst are recorded. It is suggested that the condition is a type of cavernous haemangioma and the term haemangiomatous bone cyst is preferred. 2. A survey of the published cases suggests that in its early stages the lesion is amenable to local surgery, which is the treatment of choice, but for inaccessible lesions deep x-ray therapy may be effective

The internal pressure of simple bone cysts was found to be slightly higher than the normal pressure of the bone marrow in the contralateral limb. The pressure within the cyst was measured during drilling with a Kirschner wire; it gradually decreased as the number of drill-holes increased. The PO2 of the cyst fluid was markedly lower than that of either venous or arterial blood measured synchronously. It is suggested that venous obstruction in the bone is the likely cause of these cysts. Seven patients with simple bone cysts were treated by the multiple drill-hole method, and the clinical outcome was excellent. Multiple drilling may prove to be the treatment of choice for simple bone cysts in the younger patient, as it presents fewer hazards than other procedures

We describe a consecutive series of 26 patients with simple bone cysts who were treated by curettage, multiple drilling and continuous decompression by the insertion of either a cannulated screw or a pin. In the first 15 patients we used titanium cannulated screws (group 1) and in the next 11 a cannulated hydroxyapatite pin (group 2). Satisfactory healing was achieved in 12 patients in group 1 (80%) and in all in group 2. This technique seems to be a promising option for the treatment of simple bone cysts. The cannulated hydroxyapatite pin is recommended because of its higher success rate and the fact that it does not need to be removed

Introduction and Objective. Aneurysmal bone cyst (ABC) of the spine is a locally aggressive benign lesion which can be treated by en bloc resection with wide margin to reduce the risk of local recurrence. To avoid morbidity associated with surgery, selective arterial embolization (SAE) can be considered the first-line treatment for ABCs of the spine. Other emerging treatments for ABCs include bisphosphonates, percutaneous doxycycline, sclerotherapy and Denosumab. In addition, we previously introduced the use of autologous bone marrow concentrate (BMC) injection therapy to stimulate bone healing and regeneration in ABC of the spine. One of the potential advantages of such a method is that surgical treatments are not necessary, thus allowing for both a minimally invasive approach and the treatment of poorly accessible lesions. In this prospective study we described the clinical and radiological outcomes of percutaneous injection of autologous BMC in a series of patients affected by ABCs of the spine and followed for at least one year. Materials and Methods. Fourteen patients (6 male, 8 female) were treated between June 2014 to December 2019 with BMC injection for ABC of the spine. The mean age was 17.85 years. The mean follow up was 37.4 months (range 12– 60 months). The dimension of the cyst and the degree of ossification were measured by Computed Tomography (CT) scans before the treatment and during follow-up visits. Results. Six patients received a single dose of BMC, five patients received two doses and in three patients three doses of BMC were administered. The mean ossification of the cyst (expressed in Hounsfield units) increased statistically from 43.48±2.36 HU to 161.71±23.48 HU during follow-up time and the ossification was associated to an improvement of the clinical outcomes. The mean ossification over time was significantly higher in patients treated with a single injection compared to patients treated with multiple injections. No significant difference in ossification was found between cervical and non-cervical localization of the cyst. Moreover, the initial size of the cyst was not statistically associated with the degree of ossification during follow-up. We also observed that five out of six female patients (83.3%) were less than sixteen years old and four of these (66.7%) were managed with a single dose of BMC injection, while a higher percentage of male patients (6/8, 75%) were more than sixteen years old and more than one injection was administered to them. Conclusions. The results of this study reinforce our previous evidence on the use of BMC as a valid alternative for spinal ABC management when SAE is contraindicated or ineffective. The initial size of the cyst and its localization does not influence the efficacy of the treatment. However, BMC injection could be indicated as treatment of choice for spinal ABC in young adolescent women

We report the results of the treatment of nine children with an aneurysmal bone cyst of the distal fibula (seven cysts were juxtaphyseal, and two metaphyseal). The mean age of the children was 10 years and 3 months (7 years and 4 months to 12 years and 9 months). All had open physes. All cysts were active and in seven cases substituted and expanded the entire width of the bone (type-2 lesions). The mean longitudinal extension was 5.7 cm (3 to 10). The presenting symptoms were pain, swelling and pathological fracture. Moderate fibular shortening was evident in one patient. In six patients curettage was performed, using phenol as adjuvant in three. Three with juxtaphyseal lesions underwent resection. A graft from the contralateral fibula (one case) and allografts (two cases) were positioned at the edge of the physis for reconstruction. The mean follow-up was 11.6 years (3.1 to 27.5). There was no recurrence. At the final follow-up there was no significant difference in the American Orthopaedic Foot and Ankle Society scores (excellent/good in all cases) and in growth disturbance, alignment, stability and bone reconstitution, but in the resection group the number of operations, including removal of hardware, complications (two minor) and time of immobilisation/orthosis, were increased. Movement of the ankle was restricted in one patient. The potential risks in the management of these lesions include recurrence, physeal injury, instability of the ankle and hardware and graft complications. Although resection is effective it should be reserved for aggressive or recurrent juxtaphyseal lesions

Old calcified fibrin coagula are frequently found in simple bone cysts. They provide a scaffold on which new bone is laid down, in a process analogous to endochondral ossification. It is suggested that these coagula are derived in substantial part from the plasma-like contents of the cyst, after the release of plasma-clotting factors as the result of injury. Major haemorrhage is not involved and in many cases there is no antecedent fracture. The phenomenon is not seen in other common cystic conditions of bone and its recognition is thus helpful in the histological diagnosis of simple bone cyst. Cystic bone infarcts and their possible confusion with simple bone cysts are also briefly discussed

We describe the treatment by subperiosteal resection of an aneurysmal bone cyst in the distal fibula in eight patients and highlight the role of the periosteum in the regeneration of bone defects. The mean age of the patients was 13.5 years (12 to 17). Seven had an open growth plate. The mean size of the resected specimen was 5.12 cm (3.5 to 8.0). None of the patients received instillation of bone marrow, autogenous bone graft, allograft or any synthetic bone substitutes. All had complete regeneration of the bone defect within three to nine months, with no joint instability or recurrence. The mean length of follow-up was 11.5 years (2 to 18). At the final follow-up there was no difference in the range of movement, alignment or stability of the ankle when compared with the opposite side. The periosteum played a major role in the complete filling of the bone defects and avoided the morbidity of other techniques

Treatment of unicameral bone cysts ranges from injections of corticosteroids, bone marrow with allogenic demineralised bone matrix to open bone grafting procedure. These procedures have their own disadvantages in form of infection, fracture, long-term morbidity, repeat procedure and high recurrence rate. We describe here a new, technically simple and safe technique with minimal morbidity and short hospital stay. We treated 2 young children with active bone cyst (that did not heal with pathological fractures in past 18 months) by this technique and in both the cases bone cyst healed without any complications. In patient with active bone cyst at the proximal end of humerus, under image intensifier control distal humerus perforated with 3.5 mm drill and a pre bent 2.5 mm, flexible, intramedullary nail passed into the medullary canal and then to proximal end of bone cyst. Nail now rotated sequentially at 5 mm intervals to destroy the architecture of the cyst completely until no resistance is felt. Wound closed with skin sutures and steristrips. Post operatively both children were comfortable and discharged home next day. In both cases cyst healed uneventfully. Though we have small experience but technique looks very promising

Purpose: Aneurysmal bone cyst is a benign osteodystrophic pseudotumor. It can occur as a primary lesion or develop on a pre-existing lesion. The etiopathogenesis, diagnosis and treatment remain subjects of interest. Material and methods: For this retrospective analysis, we collected 48 peripheral aneurysmal bone cysts over a 27-year period. Most cysts occurred in children, adolescents, or young adults, with a slight female predominance. Imaging included standard x-rays, computed tomography, and for the more recent cases magnetic resonance imaging (MRI). MRI provided new imaging features increasing diagnostic accuracy. Second readings of histology slides enabled establishment of the correct diagnosis in certain cases but differential diagnosis was established only with benign tumours. Surgical treatment predominated. Other treatments included curettage-filling with cancellous bone, resection, resection-reconstruction,curettage-filling with cement. Adjuvant treatments mainly involved use of calcitonin. Therapeutic abstention with surveillance confirmed the possibility of spontaneous regression after biopsy. Curettage-filling with cancellous bone was performed in 58% of cases, giving an Enneking function score of 95.7%. Results: We reviewed outcome at mean 7 years follow-up. There were four recurrent cysts and the mean global Enneking score was 95%. Our series showed the several methods can be used for the treatment of aneurysmal bone cysts, the indication taking into consideration the patient’s age, the location of the lesion and is progression. We propose a therapeutic schema. The role of calcitonin remains to be determined. Conclusion: The diagnosis of bone cysts requires a close collaboration between the surgeon, the radiologist, and the pathologist. The indication for surgery must be made case by case to achieve cure without sequelae

Aim: The purpose of this study was to describe the prevalence, recurrence rate and disease-free interval of aneurysmal and juvenile bone. Methods: A analysis of 141 cases of cystic bone lesions recorded in the Vienna Bone Tumor Registry between 1970 and 2000 was performed. 73 aneurysmal and 68 juvenile bone cysts were registered. 128 (92%) cases were managed by intralesional curettage and adjunctive chemical cautery with phenol followed by bone grafting. Seven cases (4%) were treated by single curettage, in four cases (2.8%) a marginal enbloc resection was performed and two (1.2%) cases were treated by intracystic injections of methylprednisolone acetate. All patients were followed up for a mean of 36 months (range, seven to 144 months) with frequent clinical and radiological examination. Results: The annual prevalence of aneurysmal bone cyst was between 0 and 1.238 per 105 individuals and for juvenile bone cyst between 0 and 0.963. The median age was 11.1 years (range 1– 19.7 years) with a male to female ratio of 1:1.81 for aneurysmal bone cyst and 10.4 years (range 0.5–19.9 years) and a rate of 1:1.96 for juvenile bone cyst. The cumulative probability of a survival without months after surgery was 0.83 (95% confidence interval, 0.77 to 0.90) for aneurysmal bone cyst and 0.79 (95% confidence interval, 0.69 to 0.90) for juvenile bone cyst. Conclusion: We think that the intralesional curettage with additional phenol induced cautery followed by bone grafting provides excellent results and is a successful and sufficient procedure in the therapy of these non-neoplastic bone lesions

Aim: To evaluate the role of selective arterial embolization of Aneurysmal Bone Cyst of the mobile spine (C1-L5). Ten to 35% of aneurysmal bone cyst arises from the mobile spine. The course of the disease depends on the aggressiveness of the tumor, as well as the treatment. No previous series analyses this aspect. Methods: Fourteen cases of Aneurysmal Bone Cyst of the mobile spine were retrospectively reviewed. All charts, radiographs, and images were reviewed allowed for oncologic and surgical staging of these cases. The mean follow-up was 3,5 years (2,5y Ð 11y) and the mean age at diagnosis was 22 years. Lumbar and cervical spine was more frequently involved (5 cases cervical and 5 lumbar). Histologic diagnosis was obtained in all cases. A slow and gradual onset of pain was the constant symptom. In all cases an arterial study was performed and in thirteen cases a selective arterial embolization (SAE) was performed. Six of them were repeated Results:Only two patients shows complete ossiþcation of the cyst without surgery (T10 and T1) and was curative. All the others patients received surgical treatment (curettage or en bloc excision) In three of them a recurrence of disease was diagnosed 6, 8 and 12 months later. Two of the most recent cases shows a little lityc area without symptoms Conclusions: Selective arterial embolization seems NOT be sufþcient to obtain ossiþcation of Aneurysmal Bone Cyst o mobile spine

1. The clinical, radiographic and pathological features of aneurysmal bone cyst are described and illustrated by case reports. 2. Reasons are given for accepting the lesion as a clinical and pathological entity. 3. The cyst has a tendency to spontaneous regression and healing may occur after partial excision