Sex related difference in postoperative pain and opioid use following posterior spinal fusion for adolescent idiopathic scoliosis.

PURPOSE: This project aims to evaluate the relationship between biological sex and postoperative pain and in patients receiving posterior spinal fusion for adolescent idiopathic scoliosis. METHODS: This is a retrospective study of patients (n=137) aged 10-17 receiving posterior spinal fusion for adolescent idiopathic scoliosis between 01/2018 and 09/2022. Each patient received surgery by the same pediatric orthopedic surgeon with identical postoperative pain management regimen at a children's hospital or a tertiary referral center with a pediatric spine program. RESULTS: There were no significant differences in any background characteristics between the male and female patients, including age, BMI, number of levels fused, preoperative degree of scoliosis, and length of surgery and anesthesia (p>0.05). There were no differences in amount given of any intraoperative medications, nor in amount of postoperative scheduled analgesics (p>0.05). Female patients demonstrated higher average pain scores on Visual Analogue Scale evaluations during the first 24 hours postoperatively (5.0 vs 3.6, p<0.0001), 24-48 hours postoperatively (4.9 vs 4.0, p=0.03), and at the first physical therapy evaluation (5.3 vs 3.8, p<0.001). These patients received significantly greater amounts of morphine milligram equivalents in the first 24 hours postoperatively (42.2 vs 31.5, p=0.01) and for the hospitalization in total (63.8 vs 51.3, p=0.048). There was no difference in hours until hospital discharge (44.3 vs 42.6, p=0.62) nor until first ambulation (20.1 vs 21.3, p=0.24) between the female and male patients. CONCLUSION: The influence of biopsychosocial factors on postoperative pain in adolescents is complex. This study adds to the existing pool of literature suggesting differences in pain perception between adolescent female and male patients. Female patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis may benefit from increased preoperative counseling and more aggressive intra- and postoperative pain management regimens.

Evidence for a Multimodal Pain Management Regimen in Reduction of Postoperative Opioid Use in Pediatric Patients Receiving Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: This project aims to evaluate the relationship between increased use of intraoperative nonopioid analgesics, muscle relaxers, and anesthetics and postoperative outcomes, including opioid utilization, time until ambulation, and hospital length of stay. SUMMARY OF BACKGROUND DATA: Adolescent idiopathic scoliosis (AIS) is a structural deformity of the spine that occurs in otherwise healthy adolescents, occurring with a frequency of 1% to 3%. Up to 60% of patients receiving spinal surgeries, particularly posterior spinal fusion (PSF), experience at least 1 day of moderate-to-severe pain after surgery. PATIENTS AND METHODS: This is a retrospective chart review of pediatric patients aged 10 to 17 having received PSF with >5 levels fused for AIS at a dedicated children's hospital and a regional tertiary referral center with a dedicated pediatric spine program between January 2018 and September 2022. A linear regression model was used to evaluate the influence of baseline characteristics and intraoperative medications on the total amount of postoperative morphine milligram equivalents received. RESULTS: There were no significant differences in the background characteristics of the two patient populations. Patients receiving PSF at the tertiary referral center received equivalent or greater amounts of all nonopioid pain medications and demonstrated decreased time until ambulation (19.3 vs . 22.3 h), postoperative opioid use (56.1 vs . 70.1 MME), and postoperative hospital length of stay (35.9 vs . 58.3 h). Hospital location was not individually associated with a difference in postoperative opioid use. There was not a significant difference in postoperative pain ratings. When accounting for all other variables, liposomal bupivacaine had the greatest contribution to the decrease in postoperative opioid use. CONCLUSION: Patients receiving greater amounts of nonopioid intraoperative medications utilized 20% fewer postoperative morphine milligram equivalents, were discharged 22.3 hours earlier and had earlier recorded evidence of mobility. Postoperatively, nonopioid analgesics were as effective as opioids in the reduction of subjective pain ratings. This study further demonstrates the efficacy of multimodal pain management regimens in pediatric patients receiving PSF for AIS.

Spine and Lower Extremity Kinematics Exhibited During Running by Adolescent Idiopathic Scoliosis Patients With Spinal Fusion.

STUDY DESIGN: Case-controlled design; biomechanics laboratory setting. OBJECTIVE: To compare the spine and lower extremity kinematics displayed during high-effort running between individuals with spinal fusion surgery for adolescent idiopathic scoliosis (SF-AIS) and healthy controls (CON). SUMMARY OF BACKGROUND DATA: Individuals with SF-AIS often return to exercise and sports that include running. However, how these individuals produce the spinal rotations needed during high-effort running and thus compensate for the loss of spinal flexibility is not known. METHODS: Ten SF-AIS (posterior-approach spinal fusion; postoperative time: 2.0 ± 0.6 years; physically active) and 10 CON individuals, pair-matched for gender, age, mass, height, and level of physical activity participated. SF-AIS individuals ran on a treadmill at a self-selected submaximal speed perceived as "hard" (15/20 on Borg perceived-effort scale), and CON ran at the SF-AIS pair-matched speed. 3D motion capture system was used to generate trunk and pelvis segmental angles (trunk segments = upper trunk [C7-T8], middle trunk [T9-T12], lower trunk [L1-L5]), relative angles (relative angles between the two consecutive trunk segments), and lower extremity joint angles. The group differences between the SF-AIS and CON were assessed using one-way analysis of covariance (with running speed as the covariate) for trunk, lower extremity, and step kinematics. RESULTS: SF-AIS participants exhibited a significantly greater (6.1° greater) lower trunk and (6.3° greater) pelvis segmental axial rotation compared with CON during running. In addition, SF-AIS participants displayed a 9.2° less ankle plantarflexion during the support phase. There were no significant differences detected for step kinematics. CONCLUSION: Possibly because of relearned compensatory mechanism, individuals with SF-AIS displayed similar patterns of spine, lower extremity, and step kinematics as healthy controls during high-effort running with some exceptions. LEVEL OF EVIDENCE: Level III.

Postural control of individuals with spinal fusion for adolescent idiopathic scoliosis.

BACKGROUND: The purpose of the study was to assess the postural stability and complexity of postural control for moderately physically active individuals with spinal fusion for adolescent idiopathic scoliosis at two years post-operation. METHODS: Limit of stability test and sensory organization test were conducted for 10 moderately physically-active participants with spinal fusion and 10 controls pair-matched for mass, height and physical activity level. During the limit of stability test, participants were instructed to lean the center of gravity as far as possible toward 8 predetermined directions and the maximum excursion and direction control were analyzed. During the sensory organization test, participants were instructed to maintain as still as possible in six test conditions and equilibrium scores and sway area of center of pressure were analyzed. Multi-scale entropy of center of pressure was calculated to quantify sway complexity. FINDINGS: Most postural stability outcomes of spinal fusion participants were comparable to controls except for significantly reduced equilibrium scores (p = 0.039, partial η2 = 0.217). Moreover, spinal fusion participants exhibited tendencies of reduced direction control (p = 0.053) during the limit of stability test and greater sway area (p = 0.052) during the sensory organization test. INTERPRETATION: Although the center of gravity control might be affected, spinal fusion individuals who were moderately physically active likely progressively learned to adapt postoperatively to their fused spine to meet the postural demands required when performing physical movements. We suggest that spinal fusion is a satisfactory treatment in regard to the recovery of postural stability.

Spine kinematics exhibited during the stop-jump by physically active individuals with adolescent idiopathic scoliosis and spinal fusion.

BACKGROUND CONTEXT: Individuals with adolescent idiopathic scoliosis post spinal fusion often return to exercise and sport. However, the movements that individuals with spinal fusion for adolescent idiopathic scoliosis (SF-AIS) use to compensate for the loss of spinal flexibility during high-effort tasks are not known. PURPOSE: The objective of this study was to compare the spinal kinematics of the trunk segments displayed during the stop-jump, a maximal effort task, between SF-AIS and healthy control groups. STUDY DESIGN: The study used a case-controlled design. MATERIALS AND METHODS: Ten SF-AIS (physically active, posterior-approach spinal fusion: 11.2±1.9 fused segments, postop time: 2±.6 years) and nine control individuals, pair matched for gender, age (17.4±1.3 years and 20.6±1.5 years, respectively), mass (63.50±12.2 kg and 66. 40±10.9 kg), height (1.69±.09 m and 1.72±.08 m), and level of physical activity, participated in the study. Individuals with spinal fusion for adolescent idiopathic scoliosis and controls (CON) performed five acceptable trials of the stop-jump task. Spatial locations of 21 retroreflective trunk and pelvis markers were recorded via high-speed motion capture methodology. Mean differences and analysis of covariance (jump height=covariate, p<.05) were used to compare the groups' relative angle (RelAng) and segmental angle (SegAng) of the three trunk segments (trunk segments=upper trunk [C7-T8], middle trunk [MT: T9-T12], lower trunk [LT: L1-L5]) for each rotation plane in the three phases of interest (flight, stance, and the vertical flight phases). RESULTS: No significant group differences for jump height and RelAng were detected in the three phases of stop-jump. Individuals with spinal fusion for adolescent idiopathic scoliosis displayed 3.2° greater transverse plane RelAng of LT compared with CON (p=.059) in the stance phase. Group differences for RelAng ranged from 0° to 15.3°. For SegAng in the stance phase, LT demonstrated greater SegAng in the sagittal and frontal planes (mean difference: 3.2°-6.2°), whereas SegAng for MT was 5.1° greater in the sagittal plane and had a tendency of 2° greater displacement in the frontal plane (p=.070). In the vertical flight phase, greater LT displacement in the frontal plane was observed for SF-AIS than CON. In the flight phase, LT had a tendency for greater SegAng for SF-AIS than for CON in the transverse plane (p=.089). CONCLUSIONS: Overall, SF-AIS who participate in physical activity on a regular basis are able to demonstrate similar trunk kinematics during a high-intensity stop-jump task as their matched healthy peers. Fewer group differences for relative angular displacements of the spine were observed than anticipated. This finding suggests that the fused MT appeared to be moving synchronously with the LT, thereby suggesting a compensatory adaptation of SF-AIS to achieve sufficient trunk movements during this high-effort movement.

Intratrunk Coordination During High-Effort Treadmill Running in Individuals With Spinal Fusion for Adolescent Idiopathic Scoliosis.

The purpose of the study was to determine if the intratrunk coordination of axial rotation exhibited by individuals with spinal fusion for adolescent idiopathic scoliosis (SF-AIS) during running varies from healthy individuals and how the coordination differs among adjacent trunk-segment pairs. Axial rotations of trunk segments (upper, middle, lower trunk) and pelvis were collected for 11 SF-AIS participants and 11 matched controls during running. Cross-correlation determined the phase lag between the adjacent segment motions. The coupling angle was generated using the vector coding method and classified into 1 of the 4 major, modified coordination patterns: in-phase, anti-phase, superior, and inferior phase. Two-way, mixed-model ANCOVA was employed to test phase lag, cross-correlation r, and time spent in each major coordination pattern. A significantly lower phase lag for SF-AIS was observed compared with controls. Qualitatively, there was a tendency that SF-AIS participants spent less time in anti-phase for middle-lower trunk and lower trunk-pelvis coordinations compared to controls. Phase lag and anti-phase time was significantly increased from cephalic to caudal segment pairs, regardless of group. In conclusion, SF-AIS participants and controls displayed similar patterns of intra-trunk coordination; however, the spinal fusion hindered decoupling of intra-trunk motions particularly between the lower trunk-pelvic motion.

Use of a Novel Pathway for Early Discharge Was Associated With a 48% Shorter Length of Stay After Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

INTRODUCTION: Hospital stay after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has decreased only modestly over time despite a healthy patient population. The purpose of this study was to evaluate the impact of a novel postoperative pathway on length of stay (LOS) and complications. METHODS: A retrospective review of patients undergoing PSF for AIS in 2011 to 2012 was performed at 2 institutions evaluating demographics, preoperative Cobb angles, surgical duration, blood loss, LOS, and postoperative complications. Patients at one center were managed using an accelerated discharge (AD) pathway emphasizing early transition to oral pain medications mobilization with physical therapy 2 to 3 times/d, and discharge regardless of return of bowel function. Expectations were set with the family before surgery for early discharge. Patients at the other center were managed without a standardized pathway. RESULTS: One hundred five patients underwent PSF and were treated by an AD pathway, whereas 45 patients were managed using a traditional discharge (TD) pathway. There was no difference in proximal thoracic and main thoracic Cobb magnitudes and a small difference in thoracolumbar curve magnitudes (35.2±13.0 degrees AD vs. 40.6±11.4 degrees TD, P=0.004) between groups. Surgical time was slightly shorter in AD patients (median 3.1 vs. 3.9 h, P=0.0003) with no difference in estimated blood loss. LOS was 48% shorter in the AD group (2.2 vs. 4.2 d, P<0.0001). There was no difference in readmissions or wound complications between groups. CONCLUSIONS: Hospital stay was nearly 50% shorter in patients managed by the AD pathway without any increase in readmissions or early complications. SIGNIFICANCE: Discharge after PSF for AIS may be expedited using a coordinated postoperative pathway. No increase in complications was seen using the AD pathway. Earlier discharge may reduce health care costs and allow an earlier return to normalcy for families. LEVEL OF EVIDENCE: Level III-case control study.

Clinical and economic implications of early discharge following posterior spinal fusion for adolescent idiopathic scoliosis.

OBJECTIVE: To evaluate the clinical and economic impact of a novel postoperative pathway following posterior spinal fusion (PSF) in patients with adolescent idiopathic scoliosis (AIS). METHODS: Patient charts were reviewed for demographic data and to determine length of surgery, implant density, use of osteotomies, estimated blood loss, American Society of Anesthesiologists (ASA) score, length of hospital stay, and any subsequent complications. Hospital charges were divided by charge code to evaluate potential savings. RESULTS: Two hundred and seventy-nine of 365 patients (76.4 %) treated with PSF carried a diagnosis of AIS and had completed 6 months of clinical and radiologic follow-up, a period of time deemed adequate to assess early complications. There was no difference between groups in age at surgery, sex, number of levels fused, or length of follow-up. Patients managed under the accelerated discharge (AD) pathway averaged 1.36 (31.7 %) fewer days of inpatient stay. Operative time was associated with a shorter length of stay. There was no difference in complications between groups. Hospital charges for room and board were significantly less in the AD group ($1.885 vs. $2,779, p < 0.001). CONCLUSIONS: A pathway aimed to expedite discharge following PSF for AIS decreased hospital stay by nearly one-third without any increase in early complication rate. A small but significant decrease in hospital charges was seen following early discharge. Early discharge following PSF for AIS may be achieved without increased risk of complications, while providing a small cost savings.

Predictors of emotional functioning in youth after surgical correction of idiopathic scoliosis.

BACKGROUND: Patients with idiopathic scoliosis, although otherwise healthy, often have significant concerns about their self-image and appearance. In a group of juveniles and adolescents, this can impact adjustment in school, functioning in peer groups, and general sense of well-being. There are limited data to help physicians reliably and precisely identify those who are at higher risk of poor emotional adjustment even after spine deformity correction. The purpose of this study was to determine the predictors of emotional maladjustment in juvenile and adolescent patients after surgical correction of idiopathic scoliosis. METHODS: A total of 233 juveniles, mean age 11.26 ± 1.02 (range, 8 to 12) years and 909 adolescents, mean age 14.91 ± 1.61 (range, 13 to 21) years, who underwent surgical correction for idiopathic scoliosis and who were participating in a prospective longitudinal multicenter database, were enrolled in the study. Participants completed the Scoliosis Research Society-22 (SRS-22) questionnaire before surgery and 2 years postoperatively. Radiographs were used to measure Cobb angle and surface measurements were used to determine decompensation and trunk shift. RESULTS: Adolescents reported poorer mental health preoperatively (P<0.05) and 2 years postoperatively (P<0.001) than juveniles; however, both groups reported improved mental health (P<0.001) and self-image (P<0.01) postoperatively. Mental health 2 years postoperatively was predicted by preoperative self-image (P<0.05), mental health (P<0.001), and main thoracic Cobb angle (P<0.05) in the juvenile group. Within the adolescent group, mental health 2 years postoperatively was predicted by preoperative mental health (P<0.001); self-image 2 years postoperatively was predicted by preoperative mental health (P<0.01) and self-image (P<0.001). CONCLUSIONS: Self-image and mental health are significantly improved after spine deformity correction in juveniles and adolescents with idiopathic scoliosis. However, consistent with normative development, adolescents are at higher risk for emotional maladjustment than juveniles. Surgical decision making in scoliosis correction should take the emotional status of the patient into consideration.

Inter-observer and intra-observer reliability of the Risser sign in a metropolitan scoliosis screening program.

BACKGROUND: Risser staging is one of several criteria used in scoliosis screening programs. This study aimed to evaluate the reliability of a radiologist's Risser interpretations from a large metropolitan scoliosis-screening program when compared to interpretations of 2 pediatric orthopaedic surgeons and 2 orthopaedic residents. METHODS: During the 2008 to 2009 school year, 275 students were reviewed as part of a metropolitan scoliosis-screening program. 100 of the radiographs were randomly chosen and de-identified for inclusion. Two attending orthopaedic surgeons and 2 orthopaedic residents independently interpreted the films on 3 occasions and assigned each a Risser stage. Inter- and intra-rater analyses using Kappa statistics were performed to determine the reliability of the Risser stage interpretations between the orthopaedic surgeons and the radiologist as well as the reliability of the interpretations among the individual surgeons. RESULTS: Inter-rater kappa values for the attending surgeons and the radiologist averaged 0.526. Inter-rater kappa values for the resident surgeons and the radiologist averaged 0.490 and 0.101. There was significant agreement between the attending surgeons on all 3 occasions (κ = 0.764, 0.809, 0.837). The intra-rater reliability among the attending surgeons (κ = 0.988, 0.957) and the resident surgeons (κ = 0.813, 0.495) showed statistical significance (P < 0.0001). Only half of the films had perfect agreement between the radiologist and the surgeons and 28% of the films were interpreted with a difference of 2 or more Risser stages. The radiologist did not interpret any of the films as a Risser 4 or 5 but 21% of the films were interpreted as a 4 or 5 by the orthopaedic surgeons. CONCLUSIONS: The scoliosis-screening program utilizes a referral pathway based on the radiologist's Risser stage interpretation in conjunction with the Cobb angle. The radiologist and the orthopaedic surgeons demonstrated only moderate agreement in their interpretations of Risser stages, resulting in a possible 21% over-referral rate. This study questions the efficacy of using the Risser stage as part of a large metropolitan scoliosis screening program and warrants further investigation.

Prevalence and predictors of pain in surgical treatment of adolescent idiopathic scoliosis.

STUDY DESIGN: Multicenter, prospective, consecutive clinical series. OBJECTIVE: To report on back pain and its association with patients' perceptions of appearance in a prospective cohort study of children before and after posterior spinal fusion for idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Back pain in idiopathic scoliosis has been noted to be reduced after surgery. However, uncertainty over its prevalence before and after operation persists. There is a paucity of data on correlations between patients' perceptions of their appearance and preoperative and postoperative pain. METHODS: We reviewed 1433 patients entered consecutively into the Prospective Pediatric Scoliosis Study, a database of children (8-22 years) undergoing operation for idiopathic scoliosis who have been followed for 1 and 2 years (n = 295) with the Scoliosis Research Society-22 and Spinal Appearance Questionnaire instruments. RESULTS: Preoperative pain was reported by 77.9% of patients and 44% of surgeons. More preoperative pain correlated with older age (ρ = -.140, P = 0.000), greater body mass index (ρ = -0.168, P = 0.000), larger proximal thoracic curve ρ = -0.086, P = 0.019), and a higher score on the Spinal Appearance Questionnaire Appearance (greater perception of spinal deformity, ρ = -0.223, P = 0.000) and Appearance Desire scales (stronger desire to change the appearance of their spine, ρ = -0.153, P = 0.000).Pain was reduced at 1 and 2 years after operation (P = 0.0002). Patients who perceived themselves as less deformed (ρ = -0.284, P < 0.01) or had less desire to change their spinal appearance (ρ = -0.183, P < 0.01) experienced a greater reduction in pain 2 years after operation.Preoperative analgesic use for back pain was high (28.8%) and remained high at 2 years after operation (29.5%) (P > 0.05). CONCLUSION: Back pain affects three-quarters of adolescents with idiopathic scoliosis and is reduced after posterior fusion. Patients who are overweight, older, and have larger proximal thoracic curve magnitudes report more preoperative pain. Patients who view themselves as more deformed tend to have more absolute pain, and less reduction in pain after operation.

Preoperative bracing affects postoperative outcome of posterior spine fusion with instrumentation for adolescent idiopathic scoliosis.

STUDY DESIGN.: Multicenter, prospective clinical series. OBJECTIVE.: To investigate the effect of preoperative bracing on postoperative outcome of posterior spine fusion with instrumentation for adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA.: Bracing is the standard of care for adolescent idiopathic scoliosis between 25° and 45°, yet the efficacy of bracing is questionable. It is important to evaluate the effect of bracing on outcomes in the adolescent idiopathic scoliosis population. METHODS.: We reviewed the outcomes of 281 before surgery braced and 328 before surgery nonbraced patients who underwent posterior spine fusion with instrumentation for adolescent idiopathic scoliosis before operation and at 2 years after operation using the Scoliosis Research Society instrument (SRS-30) and the Spinal Appearance Questionnaire. RESULTS.: At 2 years after operation, nonbraced patients demonstrated a greater improvement in the SRS-30 Pain domain score (0.23 vs. 0.08, P < 0.001), more improvement in back pain at rest (26.7% vs. 20.5%, P = 0.0009), and more improvement in back pain in the past 6 months (42.4% vs. 32.6%, P = 0.039) compared to braced patients. Also at 2 years after operation, nonbraced patients reported higher SRS-30 Activity domain scores (4.38 vs. 4.32, P = 0.031), Satisfaction domain scores (4.53 vs. 4.42, P = 0.007), and Total scores (4.27 vs. 4.35, P = 0.036) compared with braced patients. The 2-year Spinal Appearance Questionnaire scores showed that nonbraced patients reported a greater "decrease in importance" than braced patients in having "more even shoulders" (79.4% vs. 70.5%, P = 0.03), "more even hips" (74.6% vs. 71.6%, P = 0.042), and "more even ribs in back" (78.4% vs. 69.5%, P = 0.05). CONCLUSION.: Before surgery braced patients have more pain, lower activity levels, lower satisfaction, and lower total SRS-30 scores at 2 years after operation. Braced patients also have more "spine-specific" appearance concerns compared to nonbraced patients. These results suggest a negative impact of preoperative bracing on outcomes after posterior spinal fusion for adolescent idiopathic scoliosis. This "brace signature" should be taken into account when brace treatment is being considered.

Polybrominated diphenyl ether (PBDE) levels in dust from previously owned automobiles at United States dealerships.

The levels of BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 were determined in the dust sampled from 60 automobiles that were available for resale at U.S. dealerships. The dominant congener in automobile dust was BDE-209 comprising 95% of the total PBDE levels with a median level of 48.1 microg g(-1). Statistical analysis of the vehicle attributes indicates that the BDE-209 levels are different (p<0.05) with respect to groupings by vehicle model year, vehicle manufacturer, and the country of manufacture. Vehicle dust samples contained the characteristic profile of the PBDE congeners that comprise the PentaBDE formulation. While DecaBDE use is banned in Maine and Washington and is targeted for restriction in the near future by six U.S. states, vehicles and airplanes are exempt from the ban. It is anticipated that the human exposure potential to PBDEs from automobile dust ingestion will continue for an indefinite future period in the U.S. population.

Analysis of polybrominated diphenyl ethers (PBDEs) by liquid chromatography with negative-ion atmospheric pressure photoionization tandem mass spectrometry (LC/NI-APPI/MS/MS): application to house dust.

Eight polybrominated diphenyl ether (PBDE) congeners of primary interest to the US EPA were separated using reverse-phase liquid chromatography on an octadecylsilane column. BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 were baseline-resolved under isocratic conditions in 92:8 methanol/water (v/v). Negative-ion atmospheric pressure photoionization (NI-APPI) with a toluene dopant produced precursor ions corresponding to [M-Br+O](-) for the eight congeners studied. Each congener was quantified by tandem mass spectrometry through a unique multiple reaction monitoring (MRM) transition. On-column limits of detection were between 2.4 and 27.8 pg for the eight congeners studied, with an intra-day method precision of 9%. The LC/NI-APPI/MS/MS method was validated for the analysis of the eight PBDE congeners in NIST SRM 2585 (Organics in House Dust). Pressurized liquid extraction (PLE) with subsequent LC/NI-APPI/MS/MS analysis afforded quantitative recovery for all eight PBDE congeners with recoveries ranging from 92.7 to 113%. The liquid-phase separation of the LC/NI-APPI/MS/MS method is not prone to the thermal degradation issues that plague splitless GC based analyses of highly brominated PBDEs such as BDE-209.

Screw head impingement after in situ fixation in moderate and severe slipped capital femoral epiphysis.

In situ stabilization remains the standard of care in the treatment of stable slipped capital femoral epiphysis (SCFE). Screw placement perpendicular to the physis has shown satisfactory results with minimal complications. A prominent screw head may produce femoral acetabular impingement and pain after in situ fixation in severe SCFE. We performed a biomechanical study to establish whether screw head impingement occurs after in situ fixation of SCFE and to define the anatomy of slip severity and screw head position that may lead to impingement. A femoral neck dome osteotomy was created in a human cadaveric model simulating 2 conditions: a moderate and severe SCFEs. We tested the specimens after in situ fixation perpendicular to the simulated physis. The simulated SCFEs and normal control were tested through a full arc of motion. Coverage of the femoral head by the labrum was evaluated at 90 degrees of flexion using fluoroscopy. Impingement occurred at 70 degrees of hip flexion in the simulated moderate SCFE, and at 50 degrees of flexion in the severe simulated SCFE. Anteroposterior fluoroscopy revealed that screw heads lateral to the intertrochanteric line were unlikely to impinge on the acetabulum. Screw head impingement occurred with in situ fixation perpendicular to the physis in simulated moderate and severe SCFEs. Anteroposterior radiographs appear helpful in identifying a hip at risk for screw head impingement after in situ fixation. Alternative in situ fixation techniques (screw head resting lateral to the intertrochanteric line on the anteroposterior radiograph) may decrease the rate of screw head impingement in moderate and severe SCFEs.