Sagittal spinopelvic alignment in ambulatory persons with cerebral palsy.

PURPOSE: This study aimed to describe the spinopelvic alignment of a cohort of young ambulatory individuals with cerebral palsy (CP) and compare it to published spinopelvic alignment data for the typically developing adolescents. METHODS: Thirty-seven adolescents (18 females) with CP at GMFCS I-III were included in this retrospective case series. Lumbar lordosis and pelvic incidence were measured, and their mismatch was calculated. A model that calculates predicted lumbar lordosis based on pelvic incidence in normative data was utilized to calculate a predicted lumbar lordosis in this cohort with cerebral palsy. RESULTS: At imaging, ages were mean and standard deviation 13.5 ± 3.0 years. Pelvic incidence was 46.2° ± 12.9°, pelvic tilt was 2.8° ± 9.4°, sacral slope was 43.6° ± 10.8°, and measured lumbar lordosis was 59.4° ± 11.6°. There were no differences in pelvic incidence or lumbar lordosis among the GMFCS levels; however, pelvic incidence was higher in females. Pelvic incidence-lumbar lordosis mismatch greater than 10° was found in 67% of the cohort. Mean predicted lumbar lordosis based on the model was 54.7° ± 8.5°, averaging 8° less than measured lordosis. CONCLUSION: PI-LL mismatch was identified in 67% of this cohort of ambulatory adolescents with CP, in part due to greater lordosis than predicted by a model based on data from adolescents without CP. The implications of this finding, such as the correlation between sagittal spinopelvic alignment and quality of life in this population, should be assessed further in ambulatory patients with cerebral palsy. LEVEL OF EVIDENCE: Level IV-retrospective cohort study and literature comparison.

The Impact of Anterior Vertebral Body Tethering on Pulmonary Function.

STUDY DESIGN: Retrospective, single-center study. OBJECTIVE: To examine pulmonary function tests (PFTs) in patients undergoing anterior vertebral body tethering (AVBT). SUMMARY OF BACKGROUND DATA: The effect of AVBT on pulmonary status remains unclear. MATERIALS AND METHODS: The authors examined preoperative and postoperative PFTs following AVBT in a retrospective, single-center cohort of patients. Outcomes were compared using percent predicted values as continuous and categorical variables (using 10% change as significant) and divided into categorical values based on the American Thoracic Society standards. RESULTS: Fifty-eight patients with adolescent idiopathic scoliosis were included, with a mean age of 12.5±1.4 years and a follow-up of 4.2±1.1 years. The mean thoracic curve was 47°±9°, which improved to 21°±12°. At baseline, the mean forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) values were 79% and 82%, respectively. Four patients had normal FEV1% (≥100%), 67% had mild restrictive disease (70%-99%) and the rest had worse FEV1%. Mean FEV1 improved from 2.2 to 2.6 L ( P <0.05) and FVC improved from 2.5 to 3.0 L ( P <0.05); however, % predicted values remained unchanged (FEV1%: 79%-80%; FVC%: 82-80%, P >0.05) with mean postoperative PFTs at 37±12 months postoperative. The use of miniopen thoracotomy was not associated with worsening PFTs, but extension of the lowest instrumented vertebra below T12 was correlated with decreasing FEV1% in the bivariate analysis ( P <0.05). Patients with worse preoperative FVC% (80±13% vs. 90±11%, P =0.03) and FEV1% (77±17% vs. 87±12%, P =0.06) also had a greater likelihood of declining postoperative FEV1%. CONCLUSION: Pulmonary function in most patients undergoing AVBT remained stable (76%) or improved (14%); however, a subset may worsen (10%). Further studies are needed to identify the risk factors for this group, but worse preoperative PFTs and extension below T12 may be risk factors for worsening pulmonary function.

Results of posterior spinal fusion after failed anterior vertebral body tethering.

PURPOSE: In patients with adolescent idiopathic scoliosis (AIS) undergoing anterior vertebral tethering (AVBT), some will subsequently require posterior spinal fusion (PSF). Limited data exist on clinical and radiographic outcomes of fusion after tether failure. METHODS: 490 patients who underwent AVBT were retrospectively analyzed. Twenty patients (4.1%) subsequently underwent conversion to PSF. A control group of patients with primary PSF (no previous AVBT) was matched for comparison. Data were compared using paired t-tests and Fisher Exact Tests. RESULTS: There was a significant increase in estimated blood loss (EBL) (p = 0.002), percent estimated blood volume (%EBV) (p = 0.013), operative time (p = 0.002), and increased amount of fluoroscopy (mGy) (p = 0.04) as well as number of levels fused (p = 0.02) in the AVBT conversion group compared to primary fusion. However, no difference was found in implant density (p = 0.37), blood transfusions (p = 0.11), or intraoperative neuromonitoring events (p > 0.99). Both groups attained similar thoracic and lumbar percent correction (major coronal curve angle) from pre-op to the latest follow-up (thoracic p = 0.507, lumbar p = 0.952). CONCLUSION: A subset of patients with AVBT will require conversion to PSF. Although technically more challenging, revision surgery can be safely performed with similar clinical and radiographic outcomes to primary PSF.

Do Prophylactic Inferior Vena Cava Filters Affect the Rates of Venous Thromboembolism and Pulmonary Embolism in Patients Undergoing Major Spine Surgery?

STUDY DESIGN: Retrospective Analysis. BACKGROUND: Venous thromboembolism (VTE) represents a significant cause of morbidity and mortality in major spine surgery. Placement of prophylactic inferior vena cava filters (IVCF) in patients undergoing major spine surgery was previously adopted at our institution. This study reports our experience and compares VTE rates between patients with and without preoperative IVCF placement. METHODS: A Retrospective comparative study was conducted on adult patients who underwent IVCF placement and those who did not prior to their spinal fusion procedure, between 2013 and 2016. Thoracolumbar fusions (anterior and/or posterior) of 7 or more levels, spinal osteotomies, and a minimum of a 3-month follow-up were included. Traumatic, oncologic, and cervical pathology were excluded. Primary outcomes measured included the incidence of overall VTE (DVT/PE), death, IVCF related complications, and IVCF retrieval. RESULTS: 386 patients who underwent major spine surgery, 258 met the eligibility criteria. Of those patients, 105 patients (40.7%) had prophylactic IVCF placement. All patients had postoperative SCDs and chemoprophylaxis. The presence of an IVCF was associated with an increased rate of overall VTE (14.3% vs 6.5%, P ≤ .05) and DVT episodes (8.6% vs 2.6%, P = .04). The rate of PE for the IVCF group and non-IVCF group was 8.6% and 4.6%, respectively, which was not statistically significant (P = .32). The all-cause mortality rate overall of 2.3% was statistically similar between both groups (P = 1.0). The IVCF group had higher rates of hematoma/seroma vs the non-IVCF group (12.4% vs 3.9%, P ≤ .05). 99 IVCFs were retrievable designs, and 85% were successfully retrieved. Overall IVCF-related complication rate was 11%. CONCLUSIONS: No statistical difference in PE or mortality rates existed between the IVCF and the control group. Patients with IVCF placement experienced approximately twice the rate of VTE and three times the rate of DVT compared to those without IVCF. The IVCF-related complication rate was 11%. Based on the results of this study, the authors recommend against the routine use of prophylactic IVCFs in adults undergoing major spine surgery. LEVEL OF EVIDENCE: III.

High-accuracy longitudinal position measurement using self-accelerating light.

Radially self-accelerating light exhibits an intensity pattern that describes a spiraling trajectory around the optical axis as the beam propagates. In this article, we show in simulation and experiment how such beams can be used to perform a high-accuracy distance measurement with respect to a reference using simple off-axis intensity detection. We demonstrate that generating beams whose intensity pattern simultaneously spirals with fast and slow rotation components enables a distance measurement with high accuracy over a broad range, using the high and low rotation frequency, respectively. In our experiment, we achieve an accuracy of around 2 µm over a longitudinal range of more than 2 mm using a single beam and only two quadrant detectors. Because our method relies on single-beam interference and only requires a static generation and simple intensity measurements, it is intrinsically stable and could find applications in high-speed measurements of longitudinal position.

Symptomatic cervical spinal stenosis in spastic cerebral palsy.

AIM: To describe the prevalence of symptomatic cervical spinal stenosis (CSS) in spastic cerebral palsy (CP) and associated characteristics. METHOD: This cross-sectional study of adults (>18y) with CP (2006-2016) at a single institution compared the patient characteristics (demographics, comorbidities, surgical history, medications, Gross Motor Function Classification System [GMFCS] level, and CP type) of patients with and without CSS. RESULTS: Of 424 patients (mean age 33y 4mo, SD 13y 6mo, range 18-78y; 225 females, 199 males), 32 patients (7.5%) had symptomatic CSS. GMFCS levels in the study cohort were distributed as follows: level I, 25%; level II, 25%; level III, 22%; level IV, 19%; level V, 9%. Twenty-five out of 32 (78.1%) patients had spastic CP, two (6.3%) had dystonic CP, and one (3.1%) had mixed characteristics. Individuals with CSS were older (mean age 54y 6mo, SD 10y 5mo vs mean age 31y 7mo, SD 12y 1mo, p<0.05) and had a higher body mass index (26.1, SD 4.8 vs 23.4, SD 6.2, p<0.05) than those without CSS. Presentations included upper-extremity symptoms (73%), ambulation decline (70%), neck pain (53%), and incontinence (30%). Common stenosis levels were C5-C6 (59%), C4-C5 (56%), and C6-C7 (53%). INTERPRETATION: Symptomatic CSS was identified in 7.5% of this adult cohort during the 2006 to 2016 period. Diagnosis in CP is difficult due to impaired communication and pre-existing gait abnormalities and spasticity. Given the high prevalence of symptomatic CSS in adults, we propose developing screening guidelines. Physicians must maintain a high level of suspicion for CSS if patients present with changes in gait or spasticity.

Variability in stable sagittal vertebra (SSV) during full-length biplanar xrays can affect the choice of fusion levels in patients with adolescent idiopathic scoliosis (AIS).

PURPOSE: Surgical planning for Adolescent Idiopathic Scoliosis (AIS) relies on the coronal and sagittal plane to determine the lowest instrumented vertebra (LIV). Failure to include the stable sagittal vertebra (SSV) within the construct can increase the incidence of postoperative distal junctional kyphosis (DJK). The purpose of this study is to assess the variability of SSV within patients and to identify positional parameters that may lead to its change. METHODS: This is a case-control study of AIS patients with changes in SSV throughout serial radiographs. Radiographic sagittal parameters and hand positioning for the patients with changes in SSV were compared to patients with stable SSV. Additionally, a subgroup analysis was conducted to compare the positional parameters of only the patients with changes in SSV. RESULTS: 46 patients with a mean age of 15 ± 1.8 years old at the time of surgery were included in this study. 33/76 (43.4%) image pairs were found to have a change in SSV. Positional parameters associated with the more distally measured SSV were found to have a more negative sagittal vertebral axis (p = 0.001), more positive pelvic shift (p = 0.023), and more negative Global Sagittal Axis (p = 0.001) when compared to the more proximally measured SSV. CONCLUSION: Significant variability exists in the determination of SSV in AIS patients undergoing serial radiographs. Positional parameters associated with the proximal and distally measured SSV also have variability which indicates that posture has a significant impact on this measure. Surgeons need to be aware of SSV variability during preoperative planning and must consider multiple parameters for the determination of LIV. LEVEL OF EVIDENCE: 3.

Inter/Intraobserver Reliability of T1 Pelvic Angle (TPA), a Novel Radiographic Measure for Global Sagittal Deformity.

STUDY DESIGN: Reliability analysis. OBJECTIVE: To assess intra- and interobserver agreement of the T1 pelvic angle (T1PA), a novel radiographic measure of spinal sagittal alignment. Orthopedic surgeons of various levels of experience measured the T1PA in a series of healthy adult volunteers. The relationship of the TIPA to pelvic position was also assessed. SUMMARY OF BACKGROUND DATA: Recent literature suggests that the T1PA is a more reliable measure of global sagittal alignment than traditional measurements (i.e., sagittal vertical axis). Previous research focuses on postoperative patients with known spinal deformity. No published research exists evaluating the use of T1PA on healthy subjects without spinal deformity. The purpose of this study is: (1) to assess the reliability of measurements of the T1PA, (2) to examine its relationship to pelvic position. METHODS: Seven evaluators of varying orthopedic experience measured the T1PA in 50 healthy adult volunteers. Subjects were radiographed in each of three pelvic positions: resting, maximal anterior pelvic rotation, and maximal posterior pelvic rotation. After a washout period, the measurement was repeated. Using intraclass correlation coefficients, the intra- and inter-rater agreement for the T1PA was measured. The collected data was also used to determine the accuracy of this measurement and its relationship to pelvic position. RESULTS: A very high level of agreement was found in measurements of the T1PA (intraclass correlation coefficients r = 0.98). At each pelvic position, all examiners had excellent intrarater reliability, > 0.85. The inter-rater reliability, compared with a gold standard, consistently measured the T1PA within ±â€Š2°. The data also shows that the T1PA changes with pelvic rotation. CONCLUSION: T1PA is a reproducible and reliable measure of global sagittal alignment regardless of the level of training. The T1PA varies based on pelvic rotation; this variation must be taken into account when assigning an absolute target for correction. LEVEL OF EVIDENCE: 4.

Management of intraoperative hemorrhage during NOTES: a prospective, randomized comparison.

BACKGROUND: The optimal strategy to manage intraoperative hemorrhage during NOTES is unknown. A randomized comparison of three instruments for hemorrhage control was performed [prototype endoscopic bipolar hemostasis forceps (BELA) vs. prototype endoscopic clip (E-CLIP) applier versus laparoscopic clip (L-CLIP) applier]. METHODS: A hybrid transvaginal NOTES model in swine was used, with hemorrhage induced in either the gastroepiploic (GE) arteriovenous bundle (vessel diameter ~3 mm) or in distal mesenteric vessels (vessel diameter ~1-2 mm). Hemostasis was attempted three times per vessel using each instrument in a randomized order. Full laparoscopic salvage was performed if hemorrhage persisted beyond 10 min. Outcomes included primary success rate (PS), primary hemostasis time (PHT), number of device applications (DA), and overall hemostasis time (OHT, including salvage). RESULTS: Seventy hemostasis attempts were made in 12 swine. PS was 42-67 % for the GE vessels, with no difference between instruments. PHT and OHT also were similar between instruments, with the BELA and L-CLIP having a higher number of DA. PS was (80-100 %) in mesenteric vessels, with the BELA and L-CLIP resulting in a shorter mean PHT compared with the E-CLIP. CONCLUSIONS: All three instruments had similar effectiveness in achieving primary hemostasis during hybrid NOTES. Management of small vessel bleeding (1-2 mm) in a porcine model is effective using all three instruments but may be most efficient with the BELA or L-CLIP. Large vessel bleeding (≥3 mm) may be best managed by adding laparoscopic ports for assistance while maintaining a low threshold for conversion to full laparoscopy.

Development and evaluation of a decision-based simulation for assessment of team skills.

BACKGROUND: There is a need to train and evaluate a wide variety of nontechnical surgical skills. The goal of this project was to develop and evaluate a decision-based simulation to assess team skills. METHODS: The decision-based exercise used our previously validated Laparoscopic Ventral Hernia simulator and a newly developed team evaluation survey. Five teams of 3 surgical residents (N = 15) were tasked with repairing a 10 × 10-cm right upper quadrant hernia. During the simulation, independent observers (N = 6) completed a 6-item survey assessing: (1) work quality; (2) communication; and (3) team effectiveness. After the simulation, team members self-rated their performance by using the same survey. RESULTS: Survey reliability revealed a Cronbach's alpha of r = .811. Significant differences were found when we compared team members' (T) and observers' (O) ratings for communication (T = 4.33/5.00 vs O = 3.00/5.00, P < .01) and work quality (T = 4.33/5.00 vs O = 3.33/5.00, P < .05). The team with the greatest survey ratings was the only group to successfully complete the task. CONCLUSION: The team evaluation survey had good reliability and correlated with task performance on the simulator. Our current and previous work provides strong evidence that nontechnical and team related skills can be assessed without simulating a crisis situation.

Outcome measures for surgical simulators: is the focus on technical skills the best approach?

BACKGROUND: Mastery of operative performance is based on technical skill and intra-operative judgment. However, previous simulation studies have largely focused on technical skills and measures. This study investigates changes in operative performance when assessment and feedback focus on decision making. METHODS: Using a nonequivalent, pretest/post-test experimental design, 8 senior residents (PGY4-5) performed a laparoscopic ventral hernia repair using a newly developed box-trainer style simulator fabricated to induce surgical decision making. The pretest simulator had a 10 x 10-cm defect 5 cm above the umbilicus. The post-test simulator had a 10 x 10-cm defect in the right upper quadrant. After the pretest, faculty provided immediate feedback on operative decisions that lead to errors. In addition, residents were allowed to visually inspect their repair by removing the box trainer skins. Video-analysis using a 9-item decision making checklist was used to categorize pretest and post-test error differences. RESULTS: Common errors made during the pretest included improper visualization of the suture passer and improper mesh preparation on the back table. These errors resulted in incomplete hernia repairs by 75% of residents on the pretest. In contrast, 100% of residents successfully completed the more difficult, nonequivalent post-test hernia. Checklist analysis showed residents committed more errors on the pretest resulting in lower performance scores (score = 48.12; SD = 19.26) compared with post-test performance (score = 75.00; SD = 14.39; P < .05). CONCLUSION: Residents' decision-making skills seem to significantly affect operative performance. To facilitate mastery of operative performance, additional research is needed on simulation-based, operative skills measures that focus on intra-operative decision making.