Lateralizing calcaneal osteotomy performed with a percutaneous burr results in a significantly lower increase in tarsal tunnel pressure.

PURPOSE: Tarsal tunnel syndrome is well documented following lateralizing calcaneal osteotomy to manage varus hindfoot deformity. Traditionally, calcaneal osteotomy is performed with an oscillating saw. No studies have investigated the effect of alternative surgical techniques on postoperative tarsal tunnel pressure. The purpose of this study was to investigate the difference in tarsal tunnel pressures following lateralizing calcaneal osteotomy performed using a high-torque, low-speed "minimally invasive surgery" (MIS) Shannon burr versus an oscillating saw. METHODS: Lateralizing calcaneal osteotomy was performed on 10 below-knee cadaveric specimens. This was conducted on 5 specimens each using an oscillating saw (Saw group) or MIS burr (Burr group). The calcaneal tuberosity was translated 1 cm laterally and transfixed using 2 Kirschner wires. Tarsal tunnel pressure was measured before and after osteotomy via ultrasound-guided percutaneous needle barometer. Mean pre/post-osteotomy pressures were compared between groups. Differences were analyzed using Student's t test. RESULTS: The mean pre-procedure tarsal tunnel pressure was 25.8 ± 5.1 mm Hg in the Saw group and 26.4 ± 4.3 mm Hg in the Burr group (p = 0.85). The mean post-procedure pressure was 63.4 ± 5.1 in the Saw group and 47.8 ± 4.3 in the Burr group (p = 0.01). Change in tarsal tunnel pressure was significantly lower in the Burr group (21.4 ± 4.5) compared to the Saw group (37.6 ± 12.5) (p = 0.03). The increase in tarsal tunnel pressure was 43% lower in the Burr group. CONCLUSION: In this cadaveric study, tarsal tunnel pressure increase after lateralizing calcaneal osteotomy was significantly lower when using a burr versus a saw. This is likely because the increased width ("kerf") of the 3 mm MIS burr, compared to the submillimeter saw blade width, causes calcaneal shortening. Given the smaller increase in tarsal tunnel pressure, using the MIS burr for lateralizing calcaneal osteotomy may decrease the risk of postoperative tarsal tunnel syndrome. Future research in vivo should explore this.

The Association between Race/Ethnicity and Cancer Stage at Diagnosis of Bone Malignancies: A Retrospective Cohort Study.

INTRODUCTION AND OBJECTIVE: Limited data exists analyzing disparities in diagnosis regarding primary bone neoplasms (PBN). The objective of our study was to determine if there is an association between race/ethnicity and advanced stage of diagnosis of PBN. METHODS: This population-based retrospective cohort study included patient demographic and health information extracted from the National Cancer Institute Surveillance, Epidemiology, and End Results Program (SEER). The main exposure variable was race/ethnicity categorized as non-Hispanic white (NH-W), non-Hispanic black (NH-B), non-Hispanic Asian Pacific Islander (NH-API), and Hispanic. The main outcome variable was advanced stage at diagnosis. Age, sex, tumor grade, type of bone cancer, decade, and geographic location were co-variates. Unadjusted and adjusted logistic regression analyses were conducted calculating odds ratios (OR) and corresponding 95% confidence intervals. RESULTS: Race/ethnicity was not statistically significantly associated with advanced-stage disease. Adjusted OR for NH-B was 0.94 (95% CI: 0.78-1.38), for NH-API 1.07 (95% CI: 0.86-1.33) and for Hispanic 1.03 (95% CI: 0.85-1.25). CONCLUSIONS: The lack of association between race and advanced stage of disease could be due to high availability and low cost for initial management of bone malignancies though plain radiographs. Future studies may include socioeconomic status and insurance coverage as covariates in the analysis.

Incidence of Fusion Across Total Disc Replacement With Heterotopic Ossification: Are Ball and Socket Disk Replacements Fusing With and Without Radiographic Evidence.

STUDY DESIGN: This is a level III retrospective study. OBJECTIVE: The authors aim to review the outcomes and complications of ball and socket total disk replacements (TDRs). SUMMARY OF BACKGROUND DATA: TDR is a motion-preserving technique that closely reproduces physiologic kinematics of the cervical spine. However, heterotopic ossification and spontaneous fusion after implantation of the total cervical disk have been reported in several studies to decrease the range of motion postulated by in vitro and in vivo biomechanical studies. METHODS: The medical records of 117 consecutive patients undergoing cervical TDR over a 5-year period with Mobi-C, Prodisc-C, Prestige LP, and Secure-C implants were followed. Outcomes assessed included Visual Analogue Scale neck and arm and Neck Disability Index scores. The radiographic assessment looked at heterotopic ossification leading to fusion and complication rates. RESULTS: Of the 117 patients that underwent TDR, 56% were male with the group's mean age being 46.2±10.3 years and body mass index of 18.9±13.6 kg/m. The longest follow-up was 5 years with Prodisc-C group, with overall fusion noted in 16% of patients. One patient was also noted to have fusion which was not seen radiographically but noted intraoperatively for adjacent segment disease. There has been no demonstrable radiographic fusion seen in the Prestige LP group, however, the follow-up has only been 12-24 months for this group. CONCLUSION: In this study, we have demonstrated radiographic fusion anterior to the ball and socket TDR as well as the uncovertebral joint. We postulate that with the use of a mobile core disk there is an increased potential for fusion leading to a nonfunctional disk replacement.

Decreasing radiation dose with FluoroLESS Standalone Anterior Cervical Fusion.

BACKGROUND: Radiation dose continues to be a concern especially in the field of spine surgery, where anterior and posterior instrumentation is frequently utilized to treat multiple pathologies. The authors aim to demonstrate the feasibility of decreasing the radiation dose in standalone anterior cervical discectomy and fusion (ACDF). METHODS: Standalone ACDF (S-ACDF) with 48 consecutive patients (Group 1) with a comparison control group with ACDF with an anterior cervical plate (ACP) of 49 patients (Group 2). Fluoroscopy was performed for positioning, identification of level, placement of the implant, each screw, final AP and lateral images for the first 20 patients in Group 1. Screw placement could then be performed confidently based on cosine rule of cosine (Ѳ) = adj/hyp. RESULTS: Forty-eight patients in Group 1 (S-ACDF) and 49 patients in Group 2 (ACDF-ACP). Statistical significance not demonstrated for age, BMI or gender, P=0.691, 0.947 and 0.286 respectively. Mean radiation dose in group 1 of 17.9±6.6 mAs and 0.8±0.3 mSv was significantly less compared to group 2 which was 29.8±5.4 and 1.3±0.2 mSv, P<0.001. The average radiation dose for single-level fusion in Group 1 was 12.5±3.5 mAs and 0.5±0.1 mSv this is compared to Group 2 of 27.8±3.9 mAs and 1.2±0.2 mSv, P=0.001. The average radiation dose for two level fusion in Group 1 was 22.2±5.1 mAs and 0.9±0.2 mSv this is compared to Group 2 of 33.9±6.0 and 1.4±0.3 mSv, P=0.001. CONCLUSIONS: In the outpatient setting, S-ACDF has shown a statistically significant intergroup difference in overall radiation dose, as well as single and two-level fusions, (P<0.001). We conclude that S-ACDF can decrease overall radiation exposure to patients.