Utility of expanded anterior column resection versus decompression-alone for local control in the management of carcinomatous vertebral column metastases undergoing adjuvant stereotactic radiotherapy.

BACKGROUND CONTEXT: With improvements in adjuvant radiotherapy and minimally invasive surgical techniques, separation surgery has become the default surgical intervention for spine metastases at many centers. However, it is unclear if there is clinical benefit from anterior column resection in addition to simple epidural debulking prior to stereotactic body radiotherapy (SBRT). PURPOSE: To examine the effect of anterior column debulking versus epidural disease resection alone in the local control of metastases to the bony spine. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Ninety-seven patients who underwent open surgery followed by SBRT for spinal metastases at a single comprehensive cancer center. OUTCOME MEASURES: Local tumor recurrence following surgery and SBRT. METHODS: Data were collected regarding radiation dose, cancer histology, extent of anterior column resection, and recurrence. Tumor involvement was categorized using the International Spine Radiosurgery Consortium guidelines. Univariable analyses were conducted to determine predictors of local recurrence and time to local recurrence. RESULTS: Among the 97 included patients, mean age was 60.5±11.4 years and 51% of patients were male. The most common primary tumor types were lung (20.6%), breast (17.5%), kidney (13.4%) and prostate (12.4%). Recurrence was seen in 17 patients (17.5%) and local control rates were: 85.5% (1-year), 81.1% (2-year), and 54.9% (5-year). Overall predictors of local recurrence were tumor pathology (p<.01; renal cell carcinoma and colorectal adenocarcinoma associated with poorest PFS) and undergoing anterior column debulking versus epidural decompression-alone (p=.03). Only tumor pathology predicted time to local recurrence (p<.01), though inspection of Kaplan-Meier functions showed superior long-term local control in patients with radiosensitive tumor pathologies, no previous irradiation of the metastasis, and who underwent anterior column resection versus epidural removal alone. Median time to recurrence was 288 days with 100% of lesions showing anterior column recurrence and recurrence in the epidural space. CONCLUSIONS: With the increasing shift towards surgery as a neoadjuvant to radiotherapy for patients with spinal column metastases, the role for surgical debulking has become less clear. In the present study, we find that anterior column debulking as opposed to epidural debulking-alone decreases the odds of local recurrence and improves long-term local control.

Drivers of Readmission and Reoperation After Surgery for Vertebral Column Metastases.

OBJECTIVE: To determine those clinical, demographic, and operative factors that predict 30-day unplanned reoperation and readmission within a population of adults who underwent spinal metastasis surgery at a comprehensive cancer center. METHODS: Adults who underwent spinal metastasis surgery at a comprehensive cancer center were analyzed. Data included baseline laboratory values, cancer history, demographics, operative characteristics and medical comorbidities. Medical comorbidities were quantified using the modified Charlson Comorbidity Index (CCI). Values associated with the outcomes of interest were then subjected to multivariable logistic regression to identify independent predictors of readmission and reoperation. RESULTS: A total of 345 cases were identified. Mean age was 59.4 ± 11.7 years, 56% were male, and the racial makeup was 64% white, 29% black, and 7.3% other. Forty-two patients (12.2%) had unplanned readmissions, most commonly for wound infection with dehiscence (14.2%), venous thromboembolism (14.2%), and bowel obstruction/complication (11.9%). Thirteen patients required reoperation (4%), most commonly for wound infection with dehiscence (39%) or local recurrence (23%). Multivariable analysis showed that the modified CCI (odds ratio [OR], 1.25; 95% confidence interval [CI] 1.03-1.52; P = 0.03) was an independent predictor of 30-day readmission. Independent predictors of 30-day unplanned reoperation were: black (vs. white) race (OR, 0.08; 95% CI, 0.01-0.41; P < 0.01), length of stay (OR, 1.05 per day; 95% CI, 1.00-1.09; P = 0.04), and CCI (OR, 1.72 per point; 95% CI, 1.29-2.28; P < 0.01). CONCLUSIONS: Increasing medical comorbidities is independently predictive of both 30-day unplanned readmission and reoperation after spinal metastasis surgery. Unplanned reoperation is also positively predicted by a longer index admission. Neither tumor pathology nor age predicted outcome, suggesting that poor wound-healing factors and increased surgical morbidity may best predict these adverse outcomes.

Biomechanical evaluation comparing zero-profile devices versus fixed profile systems in a cervical hybrid decompression model: a biomechanical in vitro study.

BACKGROUND CONTEXT: The use of zero-profile devices and the need for posterior fixation in conjunction with a cervical hybrid decompression model have yet to be investigated. PURPOSE: To compare the biomechanics of zero-profile and fixed profile cervical hybrid constructs composed of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). Fixed profile devices included anterior plating, whereas zero-profile devices included integrated screws. STUDY DESIGN: In vitro cadaveric biomechanical study. METHODS: Twelve fresh-frozen cadaveric spines (C2-C7) were divided into two groups of equal bone mineral density, fixed profile versus zero profile (n=6). Groups were instrumented from C3-C6 with either (1) an expandable ACCF device and a static ACDF spacer with an anterior plate (Hybrid-AP) or (2) a zero-profile ACCF spacer with adjacent zero-profile ACDF spacer (Hybrid-Z). Motion was captured for the (1) intact condition, (2) a hybrid model with lateral mass screws (LMS), (3) a hybrid model without LMS, and (4) a hybrid model without LMS following simulated repetitive loading (fatigue). RESULTS: Hybrid-AP with LMS reduced motion in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) by 77%, 88%, and 82%, respectively, compared with intact. Likewise, Hybrid-Z with LMS exhibited the greatest reduction in motion relative to intact in FE, LB, and AR by 90%, 95%, and 66%, respectively. Following simulated in vivo fatiguing, an increase in motion was observed for both groups in all planes, particularly during Hybrid-Z postfatigue condition where motion increased relative to intact by 29%. Overall, biomechanical equivalency was observed between Hybrid-AP and Hybrid-Z groups (p>.05). Three (50%) of the Hybrid-Z group specimens exhibited signs of implant migration from the inferior endplate during testing. CONCLUSIONS: Fixed profile systems using an anterior plate for supplemental fixation is biomechanically more favorable to maintain stability and prevent dislodgement. Dislodgement of 50% of the Hybrid-Z group without LMS emphasizes the necessity for posterior fixation in a zero-profile cervical hybrid decompression model.