TUMOR AND METABOLIC DISEASE PAPERS PAPER NO. 166

uHaptic Robot-Assisted Surgery Substantially Improves Contact Area for Structural Bone Allograft Reconstructions Fazel Khan, MD, Stony Brook, NY Joseph D. Lipman, MS, New York, NY John H. Healey, MD, FACS, New York, NY Andrew D. Pearle, MD, Rye, NY INTRODUCTION: Allograft reconstruction after resection of primary bone sarcomas has a non-union rate of approximately 20%. Achieving a wide surface area of contact between host and allograft bone is one of the most important factors to help reduce the non-union rate. We developed a novel technique of haptic robot-assisted surgery to reconstruct bone defects left after primary bone sarcoma resection with structural allograft. METHODS: Using a sawbone distal femur joint-sparing hemimetaphyseal resection/reconstruction model, an identical bone defect was created in six sawbone distal femur specimens. A tumor-fellowship trained orthopedic surgeon reconstructed the defect using a simulated sawbone allograft femur. First, a standard, ‘all-manual’ technique was used to cut and prepare the allograft to best fit the defect. Then, using an identical sawbone copy of the allograft, the novel haptic-robot technique was used to prepare the allograft to best fit the defect. The robotic software was programmed to ensure that the robot-assisted cuts for the structural allograft would result in a block of bone that perfectly fit the defect in the host bone. All specimens were scanned via CT. Using a separately validated technique, the surface area of contact between host and allograft was measured for both (1) the all-manual reconstruction and (2) the robot-assisted reconstruction. All contact surface areas were normalized by dividing absolute contact area by the available surface area on the exposed cut surface of host bone. RESULTS: The mean area of contact between host and allograft bone was 24% (of the available host surface area) for the all-manual group and 76% for the haptic robot-assisted group (p=0.004). Figures 1 and 2 depict representative coronal CT reconstructions of the final host-allograft reconstruction for a manually reconstructed specimen and a robotically reconstructed specimen, respectively. DISCUSSION AND CONCLUSION: This is the first report to our knowledge of using haptic robot technology to assist in structural bone allograft reconstruction of defects left after primary bone tumor resection. The findings strongly indicate that this technology has the potential to be of substantial clinical benefit. Further studies are warranted.

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PAPER NO. 167

Expandable Femur Prostheses for Bone Sarcomas in Children: Analysis of Three Different Prostheses Pietro Ruggieri, Bologna, Italy Elisa Pala, MD, Bologna, Italy Andreas F. Mavrogenis, MD, Holargos, Athens, Greece Matteo Romantini, MD Marco Manfrini, MD, Bologna, Italy INTRODUCTION: Aims of this retrospective study were 1) to describe our experience on lower-limb reconstruction with three different types of expandable prostheses in growing children with malignant bone tumor of the femur, 2) to assess the outcome of limb salvage in these patients and 3) to analyze the survival and complications related to the different prostheses used over the time. METHODS: Between 1996 and 2009, 39 expandable implants were used in 32 children with a mean age nine years at initial surgery. The minimally invasive Kotz Growing prosthesis was used in 17 cases (10 primary implant and seven revision after failure of noninvasive Repiphysis®), the non-invasive Repiphysis® in 15 cases and Stanmore® expandable prostheses in seven cases. The mean follow up was 48 months (minimum of two years). Functional evaluation and survival analysis of the children and implants were performed. RESULTS: The rate of implant-related complications was 51.3%; nine prostheses (23%) were revised because of aseptic loosening, infection and breakage. The mean total lengthening was 26 mm (4 to 165 mm) achieved by 78 procedures (2.4 procedures/ patient). Three of the nine children who reached skeletal maturity had limb length equality and six discrepancy of 15-30 mm. The survival of the children was 94% and 76% at 24 and 72 months. The survival of the primary prostheses was 90% and 70% at 24 and 72 months, respectively. Survival was significantly higher for the Kotz compared to the Repiphysis® prostheses (p= 0.026). Stanmore prostheses have promising results, but are few and with a shorter follow up, thus comparison is statistically unconclusive. The mean MSTS score was excellent (79%) without a significant difference between the types of prostheses (p= 0.934). DISCUSSION AND CONCLUSION: In the growing children expandable prostheses are an option with good and excellent oncologic and functional outcome, and limb-length equality at skeletal maturity. However, mechanical failures including aseptic loosening and breakage, dysfunction of the expansion mechanism, contractures specially around the knee, dislocation and infection were the most common complications. However, the non-invasive systems are associated with higher complication and failure rates. Early experience is promising, but further study is needed to

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

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determine long-term structural integrity of these newer designs.

PAPER NO. 168

Ewing’s Sarcoma of the Pelvic Girdle Treated with Cryoablation in Lieu of Wide Local Resection Jacob Bickels, MD, Rehovot, Israel Sholomo Dadia, MD Yair Gortzak, MD, MSc, Ra’Anana, Israel Ofer Merimsky, MD, Tel Aviv, Israel Michael Drexler, MD, Toronto, ON, Canada Isaac Meller, MD, Tel Aviv, Israel Yehuda Kollender, MD, Lehavim, Israel INTRODUCTION: Wide resection of Ewing’s sarcoma of the sacrum or periacetabular region may result in a major neurological deficit or loss of hip function and ambulation ability, respectively. The authors speculated that intralesional tumor resection with adjuvant cryoablation of the tumor cavity in lieu of wide local resection may be safely performed in patients who had Ewing’s sarcoma of the pelvic girdle and in which the tumor was confined to the affected bone. METHODS: Between 2004 and 2010, the authors treated six patients with sacral and two patients with periacetbular Ewing’s sarcoma. There were five males and three females who ranged in age from 10 to 41. Five patients had a stage IIA and three patients had a stage IIIA disease. All patients were treated with preoperative chemotherapy and following recovery from surgery, chemotherapy and radiation therapy. Surgery included intralesional tumor removal and cryoablation of the remaining tumor cavity. Patients were followed from 1 to 6.5 years. RESULTS: At their most recent follow up, none of the study patients had local tumor recurrence. All patients were ambulating without assisting devices and none had neurological deficits that were attributed to the surgical procedure. One patients who had sacral disease developed radiation-induced osteosarcoma of the sacrum. DISCUSSION AND CONCLUSION: Intralesional tumor removal with adjuvant cryoablation in patients who have pelvic Ewing’s sarcoma and in which the disease has no soft-tissue extension provide good local control and preserve function. It should be considered as the surgical treatment of choice in these patients.

PAPER NO. 169

Desmoplastic Fibroma of Bone: Curettage is the Treatment of Choice Nicola Fabbri, MD, Bologna, Italy Massimiliano De Paolis, Bologna, Italy Marco Gambarotti, Bologna, Italy Pietro Ruggieri, Bologna, Italy INTRODUCTION: “En bloc” resection has been historically suggested as elective treatment for desmoplastic fibroma. Modern “aggressive” curettage may provide adequate local control, less surgical complications and superior functional results. Purpose of this study was to investigate results of curettage with respect to both local control and functional result. METHODS: Retrospective study of 22 cases of desmoplastic fibroma. Location: long bones 13, pelvis three, small/short bones of the foot three, spine/sacrum two, scapula one. Tumor was stage 2 in 15 cases and stage 3 in seven cases. Treatment consisted of en-bloc resection in nine cases and aggressive curettage in 13 cases. En-bloc resection was most commonly performed before 1995. Oncologic result and function were assessed at the last follow up. All the patients had a minimum follow up of three years while median follow up was longer than 10 years. 1182

RESULTS: All patients were disease free at last follow up. There were no local recurrences in the resection group but incidence of major complications was 45% (four of nine patients). In the curettage group, one patient treated elsewhere developed local recurrence, subsequently successfully managed by a new curettage. Average MSTS score in the resection group was 78% (40-97%) while average score in the curettage group was 95% (93-100%). DISCUSSION AND CONCLUSION: Local control has been excellent after surgical management, either resection or curettage. Curettage is associated with less surgical complications and provides superior function. Aggressive curettage is a safe alternative to en-bloc resection in the management of desmoplastic fibroma of bone and is currently the treatment of choice at our institution.

PAPER NO. 170

Accuracy in Computer-Guided Sarcoma Surgery Luis Alberto Aponte-Tinao, MD, Buenos Aires, Argentina Lucas E. Ritacco, MD, Buenos Aires, Argentina Lucas Lopez-Millan, SR, MD, Buenos Aires, Argentina Miguel A. Ayerza, MD, Buenos Aires, Argentina Domingo L. Muscolo, MD, Buenos Aires, Argentina German L. Farfalli, MD, Buenos Aires, Argentina INTRODUCTION: Three-dimensional preoperative planning and navigation in bone tumor resections has been used in the last five years. These results were evaluated with histology considering free margin from tumor. However, accuracy of preoperative planning and navigation is not clear. The purpose of this study was to perform a method capable of evaluating the accuracy of preoperative planning and navigation system quantitatively and qualitatively in tumor resection. Thus, a comparison of distances between each osteotomy in 3D preoperative planning and the plane created in the surgical specimen CT scanned will be determined. METHODS: Twelve patients were 3D reconstructed in a virtual platform and planned determining the osteotomy position according to oncology margins in a CT-MRI image fusion. Twelve surgical anatomic specimens were 3D reconstructed after surgery and superposed on preoperative plan. A total of 22 osteotomy planes were evaluated. RESULTS: Preoperative and specimen virtual planes were transformed to points of clouds. Distances between planes were measured applying a quantitative evaluation represented in a box plot. Three-dimensional colorimetric illustrations and histograms were used in order to analyze a qualitative evaluation. The mean difference of distances between 22 preoperative planes versus the final planes obtained in the patient was of 0.76 millimeters (SD, 3.04). DISCUSSION AND CONCLUSION: Three-dimensional virtual scenarios allowed to the surgeon determining the oncology margins. Furthermore, allowed to planning osteotomies and apply these guided by navigation. Differences between planned planes and realized planes were minimal. The quantitative and qualitative validation of this system, carried on with surgical specimens, is feasible.

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

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PAPER NO. 171

PAPER NO. 172

Health Related Quality of Life Outcome Following Treatment of Soft Tissue Sarcoma

Treatment of Pelvic Bone Tumors: Resection and Reconstruction in 129 Cases

Darin Davidson, MD, Seattle, WA Ronald Barr, Hamilton, ON, Canada Aileen M. Davis, PhD, Toronto, ON, Canada Soha Riad, BSc, CCRP, Toronto, Canada Peter Ferguson, MD, Toronto, ON, Canada Jay Wunder, MD, Toronto, ON, Canada

Pietro Ruggieri, Bologna, Italy Andrea Angelini, MD, Bologna BO, Italy Carlo Romagnoli, Bologna, Italy Nicola Fabbri, MD, Bologna, Italy Elisa Pala, MD, Bologna, Italy

INTRODUCTION: Health related quality of life, measured using health state utility values, has not been reported in sarcoma populations. These values are reported as a score between 0, representing death, and 1, representing perfect health, and allow for the direct clinical interpretation of patient reported outcomes as well as use in decision analyses and cost-effectiveness analyses. The primary objective of this study is to determine the change in health related quality of life, as measured with the EQ-5D, a preference based utility measure, from the time of diagnosis to postoperative assessment at one year among patients treated for soft tissue sarcoma. METHODS: This study consisted of a retrospective cohort analysis of patients treated for soft tissue sarcoma from January 2001 until December 2009. All patients older than 16 years of age with localized soft tissue sarcoma at the time of presentation were included. Clinical variables and outcome measure scores, including the Toronto Extremity Salvage Score (TESS), Musculoskeletal Tumor Society Score (MSTS) and EuroQol EQ5D health state utility value were collected. Patient outcome was defined on the basis of the change in the EQ-5D score between the initial assessment and one year following surgery, with a clinically important difference being defined by a score of 0.06. RESULTS: A total of 220 patients were included in the study. There was no change in EQ-5D score from baseline in 45 (20%) with a mean change score of -0.01 (SD 0.03), improvement in 71 (32%) with a mean change score of 0.22 (SD 0.12), deterioration in 52 (24%) with a mean change score of -0.20 (SD 0.13), and in 52 (24%) with a mean change score of 0 (SD 0) there was no change but given the initial score, improvement was not possible. On the basis of univariate analysis the only variable associated with change in EQ-5D score at one year was the initial and one year TESS score. Neither presentation variables, nor outcome variables, including disease status at one year, were significantly associated with change in health related quality of life outcome. Sensitivity analysis of the threshold score for definition of a clinically important difference from 0.02 to 0.1 did not result in an appreciable change in the results. DISCUSSION AND CONCLUSION: This study provides evidence regarding the health related quality of life among patients treated for a soft tissue sarcoma. There was either no change or improvement in health related quality of life in 76% of patients, with the primary determinant being physical function. The sensitivity analysis demonstrated the results to be robust. The results of this study suggest that health related quality of life is either unchanged or improved in the majority of patients at one year following treatment for a soft tissue sarcoma.

1183

INTRODUCTION: Surgery of pelvic sarcomas shows higher rates of local recurrence and complications and a lower functional outcome than other localizations. According to the different types of pelvic resections and therefore the need of different reconstruction methods, the goals of surgery include local control and maintenance of good quality of life. Purposes of this retrospective study were 1) to assess the outcome and local recurrence rate after limb salvage surgery with reconstruction for bone pelvic tumors, 2) to analyze complications and their relationship with type of resection and reconstruction. METHODS: From 1990 to 2009, 231 patients with pelvic bone tumors were treated by surgical resection. Three patients with insufficient data and 99 cases treated without reconstruction were excluded. The remaining 129 were followed at a mean of six years (range two-19 years). Histologically there were 79 chondrosarcomas, 18 Ewing’s sarcomas, 18 osteosarcomas and other 14 less frequent tumors. According to Enneking’s classification, 23 patients had type I, 21 type II and one type III pelvic resection. Combined resections were performed in 23 cases (type I-II), 40 cases (type II-III), 14 cases (type I-II-III) and seven cases (type I-IV). In 31 cases there was no acetabular involvement and reconstruction was performed with allograft only (23 type I resections, seven type I-IV, one type III). Acetabular resections were reconstructed with prosthetic composite allografts in 64 cases (27 with conventional prosthesis, 34 with stemmed pelvic prosthesis, three with trabecular metal components), with allograft only in 11 cases, with prosthesis only in 10 cases, with saddle prosthesis in 12 cases and arthrodesis in one case. RESULTS: Margins were wide in 94 cases, wide but focally contaminated in 22 cases, marginal in seven cases, intralesional in six cases. Oncologic outcome showed: 73 patients continuously disease free, six no evidence of disease after treatment of relapse (three with local recurrence, one with metastases and two with both), 16 alive with disease, 29 dead of disease and five dead of other causes. Survival was 74% and 65% at five and 10 years respectively. Incidence of local recurrence was 21.7% (28 patients). Survival to local recurrence was 76% and 73% at five and 10 years, respectively. Local recurrence occurred in 20% of wide margins and 26% of inadequate margins (p=0.353); it involved periacetabular area in 22 cases out of 98 cases (22.4%) and other site, in six cases (19.4%) (p=0.839). Incidence of metastasis was 27.1% (35 patients). Average MSTS score was 21/30. Deep infection was the most common complication, observed in 27 cases (20.9%) at a mean follow up of 11 months. No statistical difference was found between reconstructions with and without allograft (p=0.257). In 14 cases, finally external hemipelvectomy was performed, due to local recurrence or infection (10.8%). DISCUSSION AND CONCLUSION: Favorable oncologic and functional outcome can be achieved in selected patients with pelvic bone tumors. Infection is a major complication requiring further surgery. The use of allografts did not increase risk of infection. External hemipelvectomy is rarely needed for recurrence or infection.

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

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PAPER NO. 173

Surgery of Skeletal Metastases in 306 Patients with Prostate Cancer Rüdiger Weiss, Stockholm, Sweden Jonathan A. forsberg, MD, New York, NY Rikard C. Wedin, MD, Stockholm, Sweden INTRODUCTION: Bone metastases are highly prevalent in patients with prostate cancer and they are commonly associated with considerable morbidity. The aim of the study was to analyze patient survival after surgery for skeletal metastases from prostate cancer. Moreover, we wanted to identify risk factors for the outcome. METHODS: This study includes 306 patients with prostate cancer operated for skeletal metastases during 1989-2010. Kaplan-Meier analysis was used to calculate survival. Cox multiple-regression analysis was performed to study risk factors and results were expressed as hazard ratios (HR). RESULTS: The median age at surgery was 72 (range 49-94) years. The median survival after surgery was six (range 0-194) months. The cumulative one-, two- and three-year survival after surgery was 29% (95%-CI 24-34), 14% (10-18) and 8% (5-11), respectively. Pathologic fractures resulted in a higher mortality (HR 1.4), while patients with lesions in the humerus (HR 0.6), and single metastases (HR 0.4) had a lower death rate. Moreover, there was a decrease in risk of death for patients younger than 70 years of age (HR 0.7). The reoperation rate was 9% (n=31). The reasons for reoperations were deep wound infection (n=10), hematoma (n=7), material (implant) failure (n=3), wound dehiscence (n=3), increasing neurological symptoms (n=2), prosthetic dislocation (n=2), and others (n=4). DISCUSSION AND CONCLUSION: The present study represents the largest cohort of men operated for skeletal lesions from prostate cancer. Our survival data and analysis of predictors for survival help to set appropriate expectations for the patients, families and medical staff.

PAPER NO. 174

Long-term Outcomes of Osteosarcoma Patients Who Underwent Intentional Marginal Resection after Chemotherapy Norio Yamamoto, MD, Kanazawa, Ishikawa, Japan Akihiko Takeuchi, MD, Kanazawa, Japan Toshiharu Shirai, MD, Kanazawa, Japan Katsuhiro Hayashi, MD, Kanazawa, Japan Yoshikazu Tanzawa, PhD, Kanazawa, Japan Hiroaki Kimura, MD, Kanazawa, Japan Kentaro Igarashi, Kanazawa, Japan Hiroyuki Tsuchiya, MD, Kanazawa, Japan INTRODUCTION: We focused on DNA repair inhibition by caffeine and used a combination of chemotherapy and caffeine administration in patients with osteosarcoma. When a favorable response to a combination of chemotherapy and caffeine administration is clinically obtained, we usually perform intentional marginal resection, which preserves the surrounding areas that are normally resected, such as ligament, nerves, blood vessels and epiphysis region. We report on the long-term outcomes of osteosarcoma patients who underwent the combination therapy and subsequently underwent intentional marginal resection. METHODS: The subjects were 43 osteosarcoma patients (30 men and 13 women) who showed excellent response to caffeine potentiated chemotherapy. The mean age was 15 years (range: 5-72 years) and the mean follow-up period was 101 months 1184

(range 22-235 months). Enneking’s surgical stage was IIB in 36 patients and IIIB in seven patients. The patients received preoperatively three to five courses of intra-arterial fusion of caffeine (1.5g/m2/day x 3days) combined with CDDP (120mg/m2/day x 1day) and ADM (30mg/m2/day x 2days). The effectiveness of chemotherapy was evaluated using plain x-ray, angiography, MRI and thallium scintigraphy. If the results of two or more imaging examinations showed effectiveness of the treatment, the patient was considered to have a complete response or partial response. RESULTS: The treatment was effective in 14 patients (Grade III) and 29 patients (Grade IV) by histological evaluation (Rosen & Huvos) that correlated with the results of imaging evaluation. Tumors located in the femur in 15 patients, tibia in 13 patients, fibula in seven patients, humerus in five patients, pelvis in two patients, and rib in one patient. For reconstruction, distraction osteogenesis was used in 10 patients, frozen autograft in eight patients, megaprosthesis in seven patients, frozen autograft + prosthesis composite in five patients, autoclaved autograft + prosthesis composite in three patients, allograft in two patients, vascularized fibula graft in one patient and no reconstruction (resection only) in eight patients. Limb function was evaluated according to ISOLS scoring system, excellent in 32 patients (74.4%), good in seven patients (16.3%), fair in three patients (7.0%), and poor in one patient (2.3%). Local recurrence was observed in only two patients from residual soft tissue. For stage IIB patients, both five- and 10year cumulative survival rates were 93.8%. The outcome (IIB + IIIB) was CDF (continuous disease free) in 26 patients, NED (no evidence of disease) in eight patients, AWD (alive with disease) in one patient, and DOD (dead of disease) in seven patients. DISCUSSION AND CONCLUSION: It is important to minimize surgical margin and to preserve healthy tissue and important structures for improving the function of the affected limb and providing optimal quality of life for the osteosarcoma patients. In the present study, intentional marginal resection was performed in osteosarcoma patients who were clinically obtained favorable responses to a combination of chemotherapy and caffeine administration. They had a good clinical course and there was no negative effect on the survival rate or local recurrence rate. Intentional marginal excision was performed in selected osteosarcoma patients who showed radiological favorable responses to a combination of chemotherapy and caffeine administration. In these patients, limb functions were well preserved with no negative effect on the survival rate or local recurrence rate.

PAPER NO. 175

uHaptic Robot-Assisted Surgery Substantially Improves Accuracy of Wide Resection of Bone Tumors Fazel Khan, MD, Stony Brook, NY Andrew D. Pearle, MD, Rye, NY Joseph D. Lipman, MS, New York, NY John H. Healey, MD, FACS, New York, NY INTRODUCTION: Accurate reproduction of the pre-operative plan is of critical importance during wide resection of primary bone tumors. Existing intraoperative strategies usually rely on rudimentary devices such as simple rulers and imprecise techniques such as gross identification of anatomic landmAK. Studies have shown that these ‘manual’ techniques are poor at consistently reproducing a pre-operative plan. As a result, the surgeon may inadvertently compromise margins or unnecessarily remove large areas of unaffected tissue such as joint surfaces or ligament attachments. We developed a novel technique of haptic robot-assisted surgery to remove primary bone sarcomas. We hypothesized that this technique more accurately reproduces a given

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

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pre-operative resection plan than the standard, ‘manual’ technique. METHODS: A laser scan was performed on six pairs of identical sawbone femurs. A joint-sparing hemimetaphyseal resection was then precisely outlined on the three-dimensional (3D) reconstructed images of each femur. A tumor fellowship-trained surgeon performed the indicated wide resection using the standard manual technique on one specimen of each pair and using the haptic robot-assisted technique on the other. The haptic robotassisted technique is similar to the manual technique in that the surgeon has control of the oscillating saw used to make the resections. However, in the haptic robot-assisted technique, a robotic arm is also attached to the saw. Using information previously inputted into the robotic software regarding the planned resection, the attached robotic arm prevents the surgeon from straying from the pre-defined planes of resection. A post-resection laser scan was performed on all specimens. These images were then quantitatively analyzed via computer to determine the accuracy of the resections with respect to the preoperative plan according to the International Organization for Standardization guidelines. RESULTS: The haptic robot-assisted technique was significantly more accurate in terms of the maximum deviation from the preoperative plan for each specimen than the traditional manual technique (p=0.001). The mean improvement in accuracy of the robotic technique over the manual technique for each specimen pair was 4.50 mm (range 1.4 to 10.6 mm). The percentage of times the maximum deviation was (i) greater than 3 mm and (ii) greater than 5 mm was 100% and 40% for the manual group and 0.0% and 0.0% for the robotic group, respectively. DISCUSSION AND CONCLUSION: This is the first report to our knowledge of using haptic robot-assisted technology to assist in wide resection of (simulated) primary bone tumors. The findings strongly indicate that this technology has the potential to be of substantial benefit in primary bone tumor resection. Further studies looking at this technology in patients and also comparing it to recently introduced computer navigation technology are warranted.

added in perfusion fluid in the case with bleeding that might interrupt viewing field. New bone formation was observed by roentgenogram in all the patients 2.3 months after surgery in UBC and 2.1 months in ABC in spite of no bone grafting. In complication, there was no infection, one fracture that healed by conservative treatment and one radial nerve palsy that could gain complete recover conservatively. But there was one failure in UBC that treated with second ESC and four failures in ABC treated with second ESC in two patients, open curettage in one. DISCUSSION AND CONCLUSION: The healing rate was 95.5% in UBC and 80% in ABC. All of the failure cases in ABC were less than 10 year-old patients. The advantages of this procedure are as follows: 1. Less surgical insult, 2. No need of bone grafting, 3. Easy to evaluate the remnant of curettage due to magnified observation, 4. Less blind areas than conventional method, 5. No need of immobilization, 6. No need of postoperative rehabilitation with early recovery of function. We conclude that this procedure is one of the good choices for the treatment of UBC and ABC.

PAPER NO. 176

Treatment of Unicameral and Aneurysmal Bone Cysts with New Method (Endoscopic Curettage without Bone Grafting) Masaaki Kobayashi, Nagoya City, Japan INTRODUCTION: In Nov. 1992 we started ESC (endoscopic curettage) without bone grafting for enchondromas in hand and have had good results. We now perform this procedure for other benign bone tumors. The purpose of this paper is to evaluate the results of this new method for unicameral and aneurysmal bone cysts (UBC and ABC). METHODS: A total of 22 patients with UBC and 20 with ABC underwent ESC without bone grafting at our hospital from 1995 to 2009. The average age at surgery was 22.3 (five to 69) years-old in UBC and 18.0 (five to 39) in ABC. The mean follow-up period was 22.3 months in UBC and 43.6 month in ABC. Usually two portals (three or four if needed) were made with several millimeter skin incisions and fenestrations of cortex bone were made. Thorough curettage of the tumor tissue was performed using curettes and electrical shaver under endoscopic visualization. Post operative final X-ray was evaluated by modified Neer classification: A (healed), B (heal with a defect), C (persistent cyst), D (recurrent cyst). A and B were regarded as healed and C and D were failure. RESULTS: Good visualization through arthroscopy was obtained in all patients except tumors in humerus or proximal femur where air tourniquet could not be used. Epinephrine was 1185

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

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PAPER NO. 177

3 4 5 6

uA New Therapeutic Limb Salvage Surgery Using Aciridine Orange in Patients with Bone Sarcomas

The detail of patients treated with AOT for osteosarcoma

1 2

1186

Radia- Func- Follow Clinical tion tional up outtherapy score months come 97 AO-RDT 77

119 113

IIB IVA IIA IIB

II II II III

No Yes Yes No

AO-RDT AO-RDT -

90 83 97 83

108 104 71 68

CDF NED CDF CDF

IIB IIB IVA

Viable Histocells on logical surgical response margin III Yes III Yes III No

AO-RDT 97 AO-RDT 100 RT(50Gy) 100

121 94 59

CDF CDF NED

IVA

III

RT(50Gy) 97

55

AWD

Case Age/ Tumor AJCC no. Sex site

INTRODUCTION: Ewing sarcoma (ES) and osteosarcoma (OS) usually occur in young patients, and treated with chemotherapy and wide resection. As a result of these therapies, the five-year survival rate of the patients showing good response to chemotherapy can be more than 80%. But the functional results are not satisfactory, because of serious deficit of normal musculoskeletal tissues. We have recently established a new limb salvage strategy which is Acridine orange (AO) therapy (AOT) for minimally invasive surgery involving tumor excision with minimal margins, supported by photodynamic surgery (PDS), photodynamic therapy (PDT) and radiodynamic therapy (RDT). This study is to investigate clinical outcome including local control, prognosis and limb function in ES and OS patients treated with AOT. METHODS: Between 1999 and 2007, four ES and six OS patients with AJCC stage IIB were treated with AOT. For the sake of AOT, we selected the patients who showed a good response to preoperative chemotherapy. All cases (n=10) received intraregional or marginal tumor excision with minimal damage of normal tissues. AOPDS, microscopic curettage was additionally performed after local administration of AO. Microscopic curettage was repeated until green fluorescence (tumor cells) had disappeared. After PDS, we performed AO-PDT. AO-RDT was performed for five cases accepted low-dose 5Gy radiotherapy after closure of the surgical wound without washing out the AO solution. RESULTS: Mean durations of follow up were 91 months. The detail of histological response using Rosen & Huvos classification to preoperative chemotherapy in each case was summarized in table I and II. All the patients showed good response by preoperative imaging assessment, whereas the histological response to chemotherapy was grade III in five patients and grade II in five patients. Not all the patients had over 90% necrosis in histological assessment by surgical specimen. Of six patients also showed viable cells at surgically resected margin with pathological examination. But nine of 10 patients were alive with CDF or NED status. Local recurrences rates were 0% and the mean score of limb function was 93% (ISOLS). DISCUSSION AND CONCLUSION: In this study, the average of limb function evaluated by ISOLS/MSTS was 93%. Of 10 patients, five (case 1, 5, 7, and 8) showed ordinary function of the limb as level before surgery to perform athletic activity. One ES patient (case 9) is now high level athlete as tennis player. Remaining four patients move fast in daily life. AOT to ES and OS improved limb function without local recurrence. Although the number of patients was not enough and evidence-level is low in this clinical study to have conclusion, these results suggest that AOT might have capability to be innovative limb salvage surgery to preserve excellent limb function with low risk of local recurrence in highgrade malignant bone tumors sensitive to chemotherapy. Viable HistoTumor cells on AJCC logical site surgical response margin 25/M Radius IIB II Yes 11/F Humerus IIB II No

Femur Femur Femur Radius

The detail of patients treated with AOT for Ewing sarcoma

Takao Matsubara, MD, Japan Katsuyuki Kusuzaki, MD, Kyoto, Japan Akihiko Matsumine, MD, PhD, Tsu City, Mie, Japan Akihiro Sudo, Prof., Tsu, Japan

Case Age/ no. Sex

24/M 21/M 21/M 33/M

CDF CDF

7 8 9

14/M Ilium 6/M Humerus 13/M Fibla Rib/ 10 11/F vertebra

Yes

Radia- Func- Follow Clinical tion tional up outtherapy score months come

PAPER NO. 178

Hip Arthroplasty for Proximal Femur Metastases: Does the Length of Stem Matter? Zhiqing Xing, MD, PhD, Houston, TX Bryan S. Moon, MD, Houston, TX Robert L. Satcher, Jr, MD, Houston, TX Patrick P. Lin, MD, Houston, TX Valerae O. Lewis, MD, Houston, TX INTRODUCTION: It remains unclear whether a long-stem hip arthroplasty is an ideal surgical option for patients with proximal femur metastases. Although a long-stem prosthesis may prophylactically protect the entire femur, the incidence of development of distal femur metastases during patient’s survival is unknown, and a long-stem prosthesis may be associated with increased cardiopulmonary complications. METHODS: We retrospectively reviewed 206 cases with proximal femur metastases treated with hip arthroplasty at our institution between 1993 to 2008. The cases were divided into three groups of femoral stem lengths: SS (short-stem) 12 to 14cm; MS (medium-stem) 20 to 24cm; LS (long-stem) 25 to 35cm. Factors reviewed included patient survival, intraoperative and postoperative complications, development of distal metastases or proximal lesion progression and prosthesis revision. RESULTS: There were 35 cases in SS group, 99 cases in MS group and 72 cases in LS group. The median follow-up period is 232 days (2 - 4853). The overall survival rate was 40% at one year. There was no difference in the overall survival rate among the SS, MS and LS groups (p=0.1912). Proximal lesion progression occurred in 5.3% cases. New distal lesion occurred in 2.4% cases. However, only three (1.5%) cases required prosthesis revision or additional distal fixation due to tumor progression, with no difference between the SS (2.9%), MS (1.0%) and LS (1.4%) groups (p=0.734). Two more cases in the SS group required prosthesis revision due to nononcological reasons including periprosthetic fracture or aseptic loosening. So the overall revision rate is 2.4%, with a significant higher revision rate in the SS group (8.6%) than in the MS (1.0%) and LS (1.4%) groups (p=0.034). The complication rate was significantly higher in the LS group (27.8%) than the combined rate in the MS and SS groups (15.7%, p=0.038), especially acute cardiopulmonary complications (18.3% vs. 7.5%, p=0.020). DISCUSSION AND CONCLUSION: The rate of prosthesis revision during patient’s survival is very low after hip arthroplasty for proximal femur metastases, and is not correlated to the stem length. The incidence of proximal lesion progression or development of new distal lesions after treatment is low during patient’s survival. A long-stem hip prosthesis is associated with a higher complication rate, especially the acute cardiopulmonary complications. Thus, the ubiquitous use of a long-stem hip prosthesis for patients with proximal femur metastases is not justified. The stem length should

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be individualized based on the lesion extent, tumor type and patient’s response to adjuvant treatments.

PAPER NO. 179

Novel Technique Development and Biomechanical Validation of Impending Pathologic Fracture Fixation Gerald E. Alexander, MD, Tampa, FL Sergio Gutierrez, PhD, Tampa, FL Brian Palumbo, MD, Clearwater, FL David Cheong, MD, Tampa, FL G. D. Letson, MD, Tampa, FL Brandon G. Santoni, PhD, PhD, Tampa, FL

PAPER NO. 180

INTRODUCTION: Multiple classifications have been proposed to guide the orthopaedic surgeons’ decision making in choosing when to prophylactically treat impending fractures. Proposed classifications, including the commonly used Mirels Score, combine both objective and subjective measures to best predict the risk of fracture through a metastatic lesion. However, in our review of the literature, no standardized model exists which may be used in physical testing to assist in the prediction of fracture risk or validate the need for fixation from a biomechanical perspective. We present biomechanical evidence that metastases significantly weaken the native bony anatomy and may predispose the affected tissue to a high risk of fracture. These findings support the continued use of prophylactic fixation of such lesions. Our method of creating a “high-risk” impending fracture is a reproducible model that may be used to biomechanically study metastatic disease in the future. METHODS: Seven pairs of matched femurs were acquired from disease-free cadavers. Baseline bone mineral density and initial radiographs were taken of all specimens. A standardized technique was used to create an osteolytic defect in the femoral neck in one femur from each matched pair. A small cortical defect was created near the fovea. A curette was then inserted into the defect and used to create an osteolytic lesion of the trabecular bone measuring 2/3 the diameter of the femoral neck. The cortical bone of the femoral neck was then thinned by 50% using a high speed bur. The contra-lateral specimen served as the intact control with no additional manipulation. The lesion was made to be 2/3 of the bony diameter of the femoral neck in accordance with Mirels Score, and the cortical bone was thinned to 50% in accordance with Harrington’s criteria. Computed tomography (CT) scans and anterior-posterior radiographs confirmed the dimensions of the lesion. Further, 3D computational finite element (FE) models of the femur with and without the lesion were developed. Each FE model was subjected to a static point load of 2.5xBW to the femoral head and maximum predicted von Mises stresses in the femoral neck were compared between the two models. For biomechanical testing, all femurs were loaded to failure in a materials testing machine at a loading rate of 2 mm/s. Failure load (N), mode and location of failure were documented. Posttesting radiographs of all specimens confirmed failure location. RESULTS: Femurs containing the lesion failed at significantly lower loads than the matched intact specimens in a predictable and reproducible manner (Intact: 11,264.15 N ± 2,838.39 N; Lesion: 5,732.32 N ± 2,125.75 N, p