Doniel Drazin, Neil Bhamb, Lutfi T. Al-Khouja, Ari D. Kappel, Terrence T. Kim, J. Patrick Johnson and Earl Brien
The aim of this study was to identify and discuss operative nuances utilizing image guidance in the surgical management of aggressive sacral tumors.
The authors report on their single-institution, multi-surgeon, retrospective case series involving patients with pathology-proven aggressive sacral tumors treated between 2009 and 2016. They also reviewed the literature to identify articles related to aggressive sacral tumors, their diagnosis, and their surgical treatment and discuss the results together with their own experience. Information, including background, imaging, treatment, and surgical pearls, is organized by tumor type.
Review of the institutional records identified 6 patients with sacral tumors who underwent surgery between 2009 and 2016. All 6 patients were treated with image-guided surgery using cone-beam CT technology (O-arm). The surgical technique used is described in detail, and 2 illustrative cases are presented. From the literature, the authors compiled information about chordomas, chondrosarcomas, giant cell tumors, and osteosarcomas and organized it by tumor type, providing a detailed discussion of background, imaging, and treatment as well as surgical pearls for each tumor type.
Aggressive sacral tumors can be an extremely difficult challenge for both the patient and the treating physician. The selected surgical intervention varies depending on the type of tumor, size, and location. Surgery can have profound risks including neural compression, lumbopelvic instability, and suboptimal oncological resection. Focusing on the operative nuances for each type can help prevent many of these complications. Anecdotal evidence is provided that utilization of image-guided surgery to aid in tumor resection at our institution has helped reduce blood loss and the local recurrence rate while preserving function in both malignant and aggressive benign tumors affecting the sacrum.
Doniel Drazin, Ziya L. Gokaslan and J. Patrick Johnson
Doniel Drazin, Mir Hussain, Jonathan Harris, John Hao, Matt Phillips, Terrence T. Kim, J. Patrick Johnson and Brandon Bucklen
Abnormal sacral slope (SS) has shown to increase progression of spondylolisthesis, yet there exists a paucity in biomechanical studies investigating its role in the correction of adult spinal deformity, its influence on lumbosacral shear, and its impact on the instrumentation selection process. This in vitro study investigates the effect of SS on 3 anterior lumbar interbody fusion constructs in a biomechanics laboratory.
Nine healthy, fresh-frozen, intact human lumbosacral vertebral segments were tested by applying a 550-N axial load to specimens with an initial SS of 20° on an MTS Bionix test system. Testing was repeated as SS was increased to 50°, in 10° increments, through an angulated testing fixture. Specimens were instrumented using a standalone integrated spacer with self-contained screws (SA), an interbody spacer with posterior pedicle screws (PPS), and an interbody spacer with anterior tension band plate (ATB) in a randomized order. Stiffness was calculated from the linear portion of the load-deformation curve. Ultimate strength was also recorded on the final construct of all specimens (n = 3 per construct) with SS of 40°.
Axial stiffness (N/mm) of the L5–S1 motion segment was measured at various angles of SS: for SA 292.9 ± 142.8 (20°), 277.2 ± 113.7 (30°), 237.0 ± 108.7 (40°), 170.3 ± 74.1 (50°); for PPS 371.2 ± 237.5 (20°), 319.8 ± 167.2 (30°), 280.4 ± 151.7 (40°), 233.0 ± 117.6 (50°); and for ATB 323.9 ± 210.4 (20°), 307.8 ± 125.4 (30°), 249.4 ± 126.7 (40°), 217.7 ± 99.4 (50°). Axial compression across the disc space decreased with increasing SS, indicating that SS beyond 40° threshold shifted L5–S1 motion into pure shear, instead of compression-shear, defining a threshold. Trends in ultimate load and displacement differed from linear stiffness with SA > PPS > ATB.
At larger SSs, bilateral pedicle screw constructs with spacers were the most stable; however, none of the constructs were significantly stiffer than intact segments. For load to failure, the integrated spacer performed the best; this may be due to angulations of integrated plate screws. Increasing SS significantly reduced stiffness, which indicates that surgeons need to consider using more aggressive fixation techniques.
Doniel Drazin, Ziya L. Gokaslan, Ehud Mendel and J. Patrick Johnson
Faris Shweikeh, Lutfi Al-Khouja, Miriam Nuño, J. Patrick Johnson, Doniel Drazin and Matthew A. Adamo
Tethered cord syndrome (TCS) is a common spinal abnormality. In this study, the authors analyzed demographics, complications, and outcomes in children and adolescents who underwent surgery for TCS.
Using the national Kids' Inpatient Database (KID), the authors retrospectively identified patients with a primary diagnosis of TCS who were treated with spinal laminectomy and discharged in 2000, 2003, 2006, and 2009. Descriptive analysis was provided for patient- and hospital-level characteristics. Mortality, complications, non-routine discharges, in-hospital length of stay (LOS), and total charges were documented for the entire cohort and age-specific cohorts (0–5, 6–10, 11–15, and 16–20 years). Comparisons by complications and age groups were conducted.
A total of 7397 children and adolescents met the criteria in the 4 studied years. The mean age was 5.7 years; 55.3% of patients were younger than 5 years, 21.5% were 6–10 years, and 16.2% were 11–15 years. Most surgeries were performed in patients who were female (55.0%) and white (64.4%) and were performed at large (49.8%), teaching (94.2%), and urban (99.1%) children's (89.3%) hospitals. The trend showed an increase in prevalence from 2000 (19.9%) to 2009 (29.6%). Common comorbidities included anomalies in spinal curvature (16.7%), urinary or bladder dysfunction (14.3%), and spinal stenosis/spondylosis (1.4%). Non-routine discharges (3.3%) were significantly higher with advancing age, increasing from 2.2% in those younger than 5 years to 9.0% in those older than 15 years (p < 0.0001). There was a similar increasing trend for complications (6.8% to 13.9%, respectively, p < 0.0001) and average LOS (3.5 to 5.1 days, respectively, p < 0.0001). Hospital charges increased with age from an average of $28,521 in those younger than 5 years to $36,855 in those older than 15 years (p < 0.0001).
There was a steady trend of increasing operative treatment for TCS over the more recent years. The nationwide analysis was also indicative of an existing disparity, based on age, in complications, outcomes, and charges following TCS surgical correction. Older children tended to have more complications, longer LOS, more non-routine discharges, and higher hospital costs. The results are highly supportive of surgery at a younger age for this condition. Future research should investigate this correlation, especially considering the efforts to control and reduce health care costs.
Lutfi T. Al-Khouja, Eli M. Baron, J. Patrick Johnson, Terrence T. Kim and Doniel Drazin
Medical care has been evolving with the increased influence of a value-based health care system. As a result, more emphasis is being placed on ensuring cost-effectiveness and utility in the services provided to patients. This study looks at this development in respect to minimally invasive spine surgery (MISS) costs.
A literature review using PubMed, the Cost-Effectiveness Analysis (CEA) Registry, and the National Health Service Economic Evaluation Database (NHS EED) was performed. Papers were included in the study if they reported costs associated with minimally invasive spine surgery (MISS). If there was no mention of cost, CEA, cost-utility analysis (CUA), quality-adjusted life year (QALY), quality, or outcomes mentioned, then the article was excluded.
Fourteen studies reporting costs associated with MISS in 12,425 patients (3675 undergoing minimally invasive procedures and 8750 undergoing open procedures) were identified through PubMed, the CEA Registry, and NHS EED. The percent cost difference between minimally invasive and open approaches ranged from 2.54% to 33.68%—all indicating cost saving with a minimally invasive surgical approach. Average length of stay (LOS) for minimally invasive surgery ranged from 0.93 days to 5.1 days compared with 1.53 days to 12 days for an open approach. All studies reporting EBL reported lower volume loss in an MISS approach (range 10–392.5 ml) than in an open approach (range 55–535.5 ml).
There are currently an insufficient number of studies published reporting the costs of MISS. Of the studies published, none have followed a standardized method of reporting and analyzing cost data. Preliminary findings analyzing the 14 studies showed both cost saving and better outcomes in MISS compared with an open approach. However, more Level I CEA/CUA studies including cost/QALY evaluations with specifics of the techniques utilized need to be reported in a standardized manner to make more accurate conclusions on the cost effectiveness of minimally invasive spine surgery.
Joseph C. Hsieh, Doniel Drazin, Alexander O. Firempong, Robert Pashman, J. Patrick Johnson and Terrence T. Kim
Revision spine surgery, which is challenging due to disrupted anatomy, poor fluoroscopic imaging, and altered tactile feedback, may benefit from CT image-guided surgery (CT-IGS). This study evaluates accuracy of CT-IGS–navigated screws in primary versus revision spine surgery.
Pedicle and pelvic screws placed with the O-arm in 28 primary (313 screws) and 33 revision (429 screws) cases in which institutional postoperative CT scans were available were retrospectively reviewed for placement accuracy. Screw accuracy was categorized as 1) good (< 1-mm pedicle breach in any direction or “in-out-in” thoracic screws through the lateral thoracic pedicle wall and in the costovertebral joint); 2) fair (1- to 3-mm breach); or 3) poor (> 3-mm breach).
Use of CT-IGS resulted in high rates of good or fair screws for both primary (98.7%) and revision (98.6%) cases. Rates of good or fair screws were comparable for the following regions: C7–T3 at 100% (good or fair) in primary versus 100% (good or fair) in revision; T4–9 at 96.8% versus 100%; T10–L2 at 98.2% versus 99.3%; L3–5 at 100% versus 99.2%; and pelvis at 98.7% versus 98.6%, respectively. On the other hand, revision sacral screws had statistically significantly lower rates of good placement compared with primary (100% primary vs 80.6% revision, p = 0.027). Of these revision sacral screws, 11.1% had poor placement, with bicortical screws extending > 3 mm beyond the anterior cortex. Revision pelvic screws demonstrated the highest rate of fair placement (28%), with the mode of medial breach in all cases directed into the sacral-iliac joint.
In the cervical, thoracic, and lumbar spine, CT-IGS demonstrated comparable accuracy rates for both primary and revision spine surgery. Use of 3D imaging of the bony pedicle anatomy appears to be sufficient for the spine surgeon to overcome the difficulties associated with instrumentation in revision cases. Although the bony structures of sacral pedicles and pelvis are relatively larger, the complexity of local anatomy was not overcome with CT-IGS, and an increased trend toward inaccurate screw placement was demonstrated.