Comparison of Hounsfield units and vertebral bone quality score for the prediction of time to pathologic fracture in mobile spine metastases treated with radiotherapy.

OBJECTIVE: Spine metastases are commonly treated with radiotherapy for local tumor control; pathologic fracture is a potential complication of spinal radiotherapy. Both Hounsfield units (HUs) on CT and vertebral bone quality (VBQ) on MRI have been argued to predict stability as measured by odds of pathologic fracture, although it is unclear if there is a difference in the predictive power between the two methodologies. The objective of the present study was to examine whether one methodology is a better predictor of pathologic fracture following radiotherapy for mobile spine metastases. METHODS: Patients who underwent radiotherapy (conventional external-beam radiation therapy, stereotactic body radiation therapy, or intensity-modulated radiation therapy) for mobile spine (C1-L5) metastases at a tertiary care center were retrospectively identified. Details regarding underlying pathology, patient demographics, and tumor morphology were collected. Vertebral involvement was assessed using the Weinstein-Boriani-Biagini (WBB) system. Bone quality of the non-tumor-involved bone was assessed on both pretreatment CT and MRI. Univariable analyses were conducted to identify independent predictors of fracture, and Kaplan-Meier analyses were used to identify significant predictors of time to pathologic fracture. Stepwise Cox regression analysis was used to determine independent predictors of time to fracture. RESULTS: One hundred patients were included (mean age 62.7 ± 11.9 years; 61% male), of whom 35 experienced postradiotherapy pathologic fractures. The most common histologies were lung (22%), prostate (21%), breast (14%), and renal cell (13%). On univariable analysis, the mean HUs of the vertebrae adjacent to the fractured vertebra were significantly lower among those experiencing fracture; VBQ was not significantly associated with fracture odds. Survival analysis showed that average HUs ≤ 132, nonprostate pathology, involvement of ≥ 3 vertebral body segments on the WBB system, Spine Instability Neoplastic Score (SINS) ≥ 7, and the presence of axial pain all predicted increased odds of fracture (all p < 0.001). Cox regression found that HUs ≤ 132 (OR 2.533, 95% CI 1.257-5.103; p = 0.009), ≥ 3 WBB vertebral body segments involved (OR 2.376, 95% CI 1.132-4.987; p = 0.022), and axial pain (OR 2.036, 95% CI 0.916-4.526; p = 0.081) predicted increased fracture odds, while prostate pathology predicted decreased odds (OR 0.076, 95% CI 0.009-0.613; p = 0.016). Sensitivity analysis suggested that an HU threshold of ≤ 132 and a SINS of ≥ 7 identified patients at increased risk of fracture. CONCLUSIONS: The present results suggest that bone density surrogates as measured on CT, but not MRI, can be used to predict the risk of pathologic fracture following radiotherapy for mobile spine metastases. More extensive vertebral body involvement and the presence of mechanical axial pain additionally predict increased fracture odds.

Improving R0 Resection Rates With a Posterior-First, 2-Stage Approach for En Bloc Resection of Locally Advanced Primary and Recurrent Anorectal Cancers Involving the Deep Pelvic Sidewall.

BACKGROUND: Using standard anterior approaches, consistent R0 resection of locally advanced primary and recurrent rectal and anal cancer involving the deep pelvic sidewall may be unattainable. Therefore, to improve R0 resection rates, we have used a posterior-first, then anterior 2-stage approach to resection of tumors in this location. OBJECTIVE: To assess the R0 resection rate and surgical outcomes of the first 10 patients operated on using this approach. DESIGN: We conducted a retrospective case series review of our prospectively maintained surgical pathology and tumor registries. SETTING: This study was conducted at the Mayo Clinic in Rochester, Minnesota. PATIENTS: Ten patients (6 female individuals, median age 53.5 years) with primary or recurrent anal or rectal cancer treated with a posterior-first, then anterior 2-stage approach were identified. MAIN OUTCOME MEASURES: The primary outcome measures were the R0 resection rate and surgical outcomes. RESULTS: An R0 resection was achieved in all 10 patients. Nine patients developed 1 or more 30-day Clavien-Dindo grade III complications. Nine patients developed gluteal wound complications ranging from superficial wound dehiscence to flap necrosis. During the follow-up period, 4 patients were found to have metastatic disease and 1 patient had local re-recurrence. LIMITATIONS: Small cohort with heterogeneous tumors and a short follow-up duration. CONCLUSION: A posterior-first, then anterior 2-stage approach has allowed us to achieve consistent R0 resection margins in locally advanced primary and recurrent rectal and anal cancers involving the deep pelvic sidewall. Poor wound healing of the posterior gluteal incision is a common complication. See Video Abstract. MEJORANDO LAS TASAS DE RESECCIN R CON UN ABORDAJE DE DOS ETAPAS PRIMERO POSTERIOR PARA LA RESECCIN EN BLOQUE DE CNCERES ANORRECTALES PRIMARIOS Y RECURRENTES LOCALMENTE AVANZADOS QUE AFECTAN LA PARED LATERAL PLVICA PROFUNDA: ANTECEDENTES:Utilizando abordajes anteriores estándares, la resección R0 consistente del cáncer de recto y ano primario y recurrente localmente avanzado involucrando la pared lateral pélvica profunda puede ser inalcanzable. Por lo tanto, para mejorar las tasas de resección R0, hemos empleado un abordaje de 2 etapas primero posterior y luego anterior para la resección de tumores en esta ubicación.OBJETIVO:Este estudio tuvo como objetivo evaluar la tasa de resección R0 y los resultados quirúrgicos de los primeros 10 pacientes operados con este abordaje.DISEÑO:Realizamos una revisión retrospectiva de series de casos de nuestros registros de patología quirúrgica y tumores mantenidos prospectivamente.AJUSTE:Este estudio se realizó en la Clínica Mayo en Rochester, Minnesota, EE. UU.PACIENTES:Se identificaron diez pacientes (6 mujeres, mediana de edad 53.5 años) con cáncer anal o rectal primario o recurrente tratados con un abordaje de dos etapas, primero posterior y luego anterior.PRINCIPALES MEDIDAS DE RESULTADO:Las medidas de resultado primarias fueron la tasa de resección R0 y los resultados quirúrgicos.RESULTADOS:Se logró una resección R0 en los 10 pacientes. Nueve pacientes desarrollaron una o más complicaciones de grado III de Clavien-Dindo a los 30 días. Nueve pacientes desarrollaron complicaciones de la herida del glúteo que variaron desde dehiscencia superficial de la herida hasta necrosis del colgajo. Durante el período de seguimiento, se encontró que 4 pacientes tenían enfermedad metastásica y un paciente tuvo recurrencia local.LIMITACIONES:Cohorte pequeño con tumores heterogéneos y corta duración de seguimiento.CONCLUSIÓN:Un abordaje en 2 etapas, primero posterior y luego anterior, nos ha permitido lograr márgenes de resección R0 consistentes en cánceres de recto y anal primarios y recurrentes localmente avanzados que afectan la pared lateral pélvica profunda. La mala cicatrización de la incisión glútea posterior es una complicación común. (Traducción-Dr. Aurian Garcia Gonzalez).

Updates in the Management of Metastatic Spine Disease.

The number of cancer diagnoses continues to increase each year in the United States, and given the propensity for bone metastases from solid organ malignancies, orthopaedic spine surgeons will inevitably encounter patients with metastatic spine disease and need to have a framework for approaching the evaluation and treatment of these complex patients. Many patients seeking care for spinal metastases already have a history of disseminated malignancy, but metastatic spine disease itself will be the presenting symptom of cancer in approximately 20% of patients. Because the first presentation of cancer may be to a spine surgeon, an appropriate strategy for the initial evaluation of a patient with a new spinal lesion is critical to establish the diagnosis of metastatic disease before undergoing treatment. Once the diagnosis of metastatic spine disease is confirmed, decisions regarding treatment should be made in coordination with a multidisciplinary team including radiation oncology and medical oncology. Spinal metastases are most often treated with radiation therapy. Direct circumferential decompression of the spinal cord with postoperative radiation therapy is considered for high-grade epidural spinal cord compression to preserve neurologic function. Mechanical spinal instability is another potential indication for surgery. When considering surgery, the patient's medical fitness, systemic burden of cancer, and overall prognosis all must be accounted for, and the importance of multidisciplinary evaluation and shared decision making cannot be overstated.

The Role of 3D Printing in Treatment Planning of Spine and Sacral Tumors.

Three-dimensional (3D) printing technology has proven to have many advantages in spine and sacrum surgery. 3D printing allows the manufacturing of life-size patient-specific anatomic and pathologic models to improve preoperative understanding of patient anatomy and pathology. Additionally, virtual surgical planning using medical computer-aided design software has enabled surgeons to create patient-specific surgical plans and simulate procedures in a virtual environment. This has resulted in reduced operative times, decreased complications, and improved patient outcomes. Combined with new surgical techniques, 3D-printed custom medical devices and instruments using titanium and biocompatible resins and polyamides have allowed innovative reconstructions.

Risk factors for sacral fracture following en bloc chordoma resection.

OBJECTIVE: The purpose of this study was to analyze risk factors for sacral fracture following noninstrumented partial sacral amputation for en bloc chordoma resection. METHODS: A multicenter retrospective chart review identified patients who underwent noninstrumented partial sacral amputation for en bloc chordoma resection with pre- and postoperative imaging. Hounsfield units (HU) were measured in the S1 level. Sacral amputation level nomenclature was based on the highest sacral level with bone removed (e.g., S1 foramen amputation at the S1-2 vestigial disc is an S2 sacral amputation). Variables collected included basic demographics, patient comorbidities, surgical approach, preoperative radiographic details, neoadjuvant and adjuvant radiation therapy, and postoperative sacral fracture data. RESULTS: A total of 101 patients (60 men, 41 women) were included; they had an average age of 69 years, BMI of 29 kg/m2, and follow-up of 60 months. The sacral amputation level was S1 (2%), S2 (37%), S3 (44%), S4 (9%), and S5 (9%). Patients had a posterior-only approach (77%) or a combined anterior-posterior approach (23%), with 10 patients (10%) having partial sacroiliac (SI) joint resection. Twenty-seven patients (27%) suffered a postoperative sacral fracture, all occurring between 1 and 7 months after the index surgery. Multivariable logistic regression analysis demonstrated S1 or S2 sacral amputation level (p = 0.001), combined anterior-posterior approach (p = 0.0064), and low superior S1 HU (p = 0.027) to be independent predictors of sacral fracture. The fracture rate for patients with superior S1 HU < 225, 225-300, and > 300 was 38%, 15%, and 9%, respectively. An optimal superior S1 HU cutoff of 300 was found to maximize sensitivity (89%) and specificity (42%) in predicting postamputation sacral fracture. In addition, the fracture rate for patients who underwent partial SI joint resection was 100%. CONCLUSIONS: Patients with S1 or S2 partial sacral amputations, a combined anterior-posterior surgical approach, low superior S1 HU, and partial SI joint resection are at higher risk for postoperative sacral fracture following en bloc chordoma resection and should be considered for spinopelvic instrumentation at the index procedure.

Preoperative Patient-reported Outcomes are not Associated With Sagittal and Spinopelvic Alignment in Degenerative Lumbar Spondylolisthesis.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of this study was to evaluate whether sagittal and spinopelvic alignment correlate with preoperative patient-reported outcomes (PROs) in degenerative lumbar spondylolisthesis (DLS) with spinal stenosis. SUMMARY OF BACKGROUND DATA: Positive global sagittal balance and spinopelvic malalignment are strongly correlated with symptom severity in adult spinal deformity, but this correlation has not been evaluated in DLS. METHODS: Patients were enrolled in the Canadian Spine Outcomes Research Network (CSORN) prospective DLS study at seven centers between January 2015 and May 2018. Correlation was assessed between the following preoperative PROs: Oswestry Disability Index (ODI), numeric rating scale (NRS) leg pain, and NRS back pain and the following preoperative sagittal radiographic parameters SS, PT, PI, SVA, LL, TK, T1SPI, T9SPI, and PI-LL. Patients were further divided into groups based on spinopelvic alignment: Group 1 PI-LL<10°; Group 2 PI-LL ≥10° with PT <30°; and Group 3 PI-LL ≥10° with PT ≥30°. Preoperative PROs were compared among these three groups and were further stratified by those with SVA <50 mm and SVA ≥50 mm. RESULTS: A total of 320 patients (61% female) with mean age of 66.1 years were included. Mean (SD) preoperative PROs were: NRS leg pain 7.4 (2.1), NRS back pain 7.1 (2.0), and ODI 45.5 (14.5). Preoperative radiographic parameters included: SVA 27.1 (33.4) mm, LL 45.7 (13.4°), PI 57.6 (11.9), and PI-LL 11.8 (14.0°). Weak but statistically significant correlations were observed between leg pain and PT (r = -0.114) and PI (ρ = -0.130), and T9SPI with back pain ( r  = 0.130). No significant differences were observed among the three groups stratified by PI-LL and PT. No significant differences in PROs were observed between patients with SVA <50 mm compared to those with SVA ≥50 mm. CONCLUSION: Sagittal and spinopelvic malalignment do not appear to significantly influence baseline PROs in patients with DLS. LEVEL OF EVIDENCE: Prognostic level II.

Effectiveness of Surgical Decompression in Patients With Degenerative Cervical Myelopathy: Results of the Canadian Prospective Multicenter Study.

BACKGROUND: Conflicting evidence exists regarding the effectiveness of surgery for degenerative cervical myelopathy (DCM), particularly in mild DCM. OBJECTIVE: To prospectively evaluate the impact of surgery on patient-reported outcomes in patients with mild (modified Japanese Orthopaedic Association [mJOA] ≥ 15), moderate (mJOA 12-14), and severe (mJOA < 12) DCM. METHODS: Prospective, multicenter cohort study of patients with DCM who underwent surgery between 2015 and 2019 and completed 1-yr follow-up. Outcome measures (mJOA, Neck Disability Index [NDI], EuroQol-5D [EQ-5D], Short Form [SF-12] Physical Component Score [PCS]/Mental Component Score [MCS], numeric rating scale [NRS] neck, and arm pain) were assessed at 3 and 12 mo postoperatively and compared to baseline, stratified by DCM severity. Changes in outcome measures that were statistically significant (P < .05) and met their respective minimum clinically important differences (MCIDs) were deemed clinically meaningful. Responder analysis was performed to compare the proportion of patients between DCM severity groups who met the MCID for each outcome measure. RESULTS: The cohort comprised 391 patients: 110 mild, 163 moderate, and 118 severe. At 12 mo after surgery, severe DCM patients experienced significant improvements in all outcome measures; moderate DCM patients improved in mJOA, NDI, EQ-5D, and PCS; mild DCM patients improved in EQ-5D and PCS. There was no significant difference between severity groups in the proportion of patients reaching MCID at 12 mo after surgery for any outcome measure, except NDI. CONCLUSION: At 12 mo after surgery, patients with mild, moderate, and severe DCM all demonstrated improved outcomes. Severe DCM patients experienced the greatest breadth of improvement, but the proportion of patients in each severity group achieving clinically meaningful changes did not differ significantly across most outcome measures.

Posterior-First Two-Stage Approach to En Bloc Resection of Locally Recurrent Rectal Cancer Involving the Pelvic Sidewall.

INTRODUCTION: Using standard anterior-only or anterior then posterior approaches can make an R0 resection difficult to achieve in patients with pelvic sidewall recurrences because of confined working spaces and poor visibility. TECHNIQUE: Given the limitations of standard approaches, we have used a novel posterior-first then anterior 2-stage approach allowing us to widely expose and secure deep margins and control vessels under direct visualization. RESULTS: We present a technical note describing this approach in patients with recurrent rectal cancer involving the pelvic sidewall with extrapelvic extension. CONCLUSION: The posterior-first approach may assist in achieving a higher number of R0 resections in patients with locally recurrent rectal cancer involving the pelvic sidewall.

Is focused magnetic resonance imaging adequate for treatment decision making in acute traumatic thoracic and lumbar spine fractures seen on whole spine computed tomography?

PURPOSE: To assess whether a focused magnetic resonance imaging (MRI) limited to the region of known acute traumatic thoracic or lumbar fracture(s) would miss any clinically significant injuries that would change patient management. STUDY DESIGN/SETTING: A multicenter retrospective clinical study. PATIENT SAMPLE: Adult patients with acute traumatic thoracic and/or lumbar spine fracture(s). OUTCOME MEASURES: Pathology identified on MRI (ligamentous disruption, epidural hematoma, and cord contusion), outside of the focused zone, an alteration in patient management, including surgical and nonsurgical, as a result of the identified pathology outside the focused zone. METHODS: Records were reviewed for all adult trauma patients who presented to the emergency department between 2008 and 2016 with one or more fracture(s) of the thoracic and/or lumbar spine identified on computed tomography (CT) and who underwent MRI of the entire thoracic and lumbar spine within 10 days. Exclusion criteria were patients with >4 fractured levels, pathologic fractures, isolated transverse, and/or spinous process fractures, prior vertebral augmentation, and prior thoracic or lumbar spine instrumentation. Patients with neurologic deficits or cervical spine fractures were also included. MRIs were reviewed independently by one spine surgeon and one musculoskeletal fellowship-trained emergency radiologist for posterior ligamentous complex (PLC) integrity, vertebral injury, epidural hematoma, and cord contusion. The surgeon also commented on the clinical significance of the pathology identified outside the focused zone. All cases in which pathology was identified outside of the focused zone (three levels above and below the fractures) were independently reviewed by a second spine surgeon to determine whether the pathology was clinically significant and would alter the treatment plan. RESULTS: In total, 126 patients with 216 fractures identified on CT were included, with a median age of 49 years. There were 81 males (64%). Sixty-two (49%) patients had isolated thoracolumbar junction injuries and 36 (29%) had injuries limited to a single fractured level. Forty-seven (37%) patients were managed operatively. PLC injury was identified by both readers in 36 (29%) patients with a percent agreement of 96% and κ coefficient of 0.91 (95% CI 0.87-0.95). Both readers independently agreed that there was no pathology identified on the complete thoracic and lumbar spine MRIs outside the focused zone in 107 (85%) patients. Injury outside the focused zone was identified by at least one reader in 19 (15%) patients. None of the readers identified PLC injury, cord edema, or noncontiguous epidural hematoma outside the focused zone. Percent agreement for outside pathology between the two readers was 92% with a κ coefficient of 0.60 (95% CI 0.48-0.72). The two spine surgeons independently agreed that none of the identified pathology outside of the focused zone altered management. CONCLUSIONS: A focused MRI protocol of three levels above and below known thoracolumbar spine fractures would have missed radiological abnormality in 15% of patients. However, the pathology, such as vertebral body edema not appreciated on CT, was not clinically significant and did not alter patient care. Based on these findings, the investigators conclude that a focused protocol would decrease the imaging time while providing the information of the injured segment with minimal risk of missing any clinically significant injuries.

Surgical management of Gorham-Stout disease of the pelvis refractory to medical and radiation therapy.

Gorham-Stout disease (GSD) is a rare condition characterized by spontaneous idiopathic bone resorption that can affect any part of the skeleton. Treatment is aimed at halting osteolysis and alleviating complications associated with bone loss. Often this can be achieved via observation and supportive management, medical treatment, and/or radiation therapy. We report a case of GSD of the pelvis that was refractory to medical and radiation therapy and was managed successfully with surgery. A 30-year-old man presented to our clinic 3 years after being diagnosed at an outside institution with GSD of the pelvis that was managed with medical treatments and radiation therapy. Despite aggressive, multimodality treatment, he was unable to ambulate without crutches and was in significant pain. The patient opted for intralesional surgery and spinopelvic fusion. Sixteen months after surgery, the patient had only mild pain and was able to ambulate with a cane. Very few cases have been reported of GSD involving the pelvis that necessitated surgical management. Significant functional impairment can occur as a result of pelvic osteolysis, and traditional management strategies focused on halting resorption may not be adequate. Surgical stabilization of the affected areas is an important treatment strategy for patients who have exhausted other options.

What are the functional results and complications from allograft reconstruction after partial hemipelvectomy of the pubis?

BACKGROUND: In patients undergoing hemipelvectomies including resection either of a portion of the pubis or the entire pubis from the symphysis to the lateral margin of the obturator foramen while sparing the hip (so-called Dunham Type III hemipelvectomies), reconstructions typically are not performed given the preserved continuity of the weightbearing axis and the potential complications associated with reconstruction. Allograft reconstruction of the pelvic ring may, however, offer benefits for soft tissue reconstruction of the pelvic floor and hip stability, but little is known about these reconstructions. QUESTIONS/PURPOSES: (1) What is the postoperative functional status after allograft reconstruction of Type III pelvic defects? (2) What are the rates of hernia, infection, and hip instability? METHODS: In this case series, we reviewed all patients with Type III pelvic resections (with or without anterior acetabular wall resections) who underwent allograft reconstruction between 2005 and 2013 at one center (N = 14). During the period in question, reconstruction was the general approach used in patients undergoing these resections; during that time, three other patients were treated without reconstruction as a result of either surgeon preference or the patient choosing to not have reconstruction after a discussion of the risks and benefits. Of the 14 patients treated with reconstruction, complete followup was available at a minimum of 1 year in 11 (other than those who died before the end of the first year; median, 19 months; range 16-70 months among those surviving), one was lost to followup before a year, and two others had partial telephone or email followup. Patient demographics, disease status, functional status, and complications were recorded. For a portion of the cohort (four patients) later in the series, we used a novel technique for anterior acetabular wall reconstruction using the concave cartilaginous surface of a proximal fibula allograft; the others received either a long bone (humerus or femur) or hemipelvis graft. Seven patients died of disease; two had local recurrence, and five died of metastatic disease. RESULTS: All patients remained ambulatory Pain at 12 months after surgery was reported as none in five, mild in two, moderate in two, and severe in one. Operative complications included infection in two, symptomatic hernia in one, hip instability in one, dislocated total hip arthroplasty on the first postoperative day in one, and graft failure in one. CONCLUSIONS: Allograft reconstruction after Type III pelvic resections can provide functional reconstruction of the pelvic ring, pelvic floor, and, in certain patients with partial anterior acetabular resections, the resected anterior acetabulum. This has implications in preventing the occurrence of hernia and hip instability in this patient population that is classically not reconstructed, although longer-term outcomes in a larger number of patients would help to better delineate this because infection, hernia, hip instability, and graft nonunion still remain concerns with this approach. The most important unanswered question remains whether, on balance, any benefits that may accrue to these patients as the result of reconstruction are offset by a relatively high likelihood of undergoing secondary or revision surgery.