Allogeneic blood transfusion and AIS surgery: how the NSQIP database can improve patient safety.

PURPOSE: Describe the experience of one institution in modifying allogeneic blood transfusion protocols for AIS surgery in response to the results of ACS-NSQIP-PEDS comparative data in a retrospective cohort study. METHODS: NSQIP data demonstrated that AIS patients at our hospital had a significantly greater risk of ALBT compared to similar institutions (OR 4.1). The ALBT protocol was then revised to initiate transfusion based on Hb/Hct level, clinical hypotension and/or discussion between surgeon and anesthesiologist. A retrospective analysis of perioperative ALBT and autologous cell salvage blood transfusion (CSBT) rates was performed for patients undergoing surgery before (Group A) and after (Group B) the implementation of the revised protocol. RESULTS: Two hundred and ninety patients constituted the study cohort, with 92 patients in Group A and 198 in Group B. Average total blood transfusion (ALBT + CSBT) per patient was significantly lower for Group B than Group A (313 ml vs. 650 ml, p < 0.01). ALBT per patient of Group B was significantly lower than Group A (85 ml vs. 324 ml, p < 0.01). 48% of patients received ALBT in Group A compared to only 18% in Group B. CONCLUSION: Recognition of excessive allogeneic transfusion rates in our institution through comparative data from the ACS-NSQIP-PEDS database resulted in the modification of transfusion parameters that led to a decrease in allogeneic transfusion rates for AIS patients. The current study highlights the value of a large, well-curated surgical database in optimizing clinical protocols and potentially improving overall surgical morbidity.

An atypical cause of sporotrichosis in a cat.

A nine-year-old domestic cat from Melbourne, Australia, presented with a non-ulcerated nodule on its nasal bridge. A fungal infection of the subcutis was diagnosed based on histopathology and culture of a white mould, which was identified as Sporothrix pallida complex by ITS1-5.8S-ITS2 and ß-tubulin gene sequencing. The cat was treated by cytoreduction, itraconazole and subsequently posaconazole, which eventually resulted in regression of residual infected tissues and clinical resolution.

Impact of gait analysis on pathology identification and surgical recommendations in children with spina bifida.

BACKGROUND: Gait analysis provides quantitative data that can be used to supplement standard clinical evaluation in identifying and understanding gait problems. It has been established that gait analysis changes treatment decision making for children with cerebral palsy, but this has not yet been studied in other diagnoses such as spina bifida. RESEARCH QUESTION: To determine the effects of gait analysis data on pathology identification and surgical recommendations in children with spina bifida. METHODS: Two pediatric orthopaedic surgeons and two therapists with >10 years of experience in gait analysis reviewed clinical, video, and gait analysis data from 43 ambulatory children with spina bifida (25 male; mean age 11.7 years, SD 3.8; 25 sacral, 18 lumbar). Primary gait pathologies were identified by each assessor both before and after consideration of the gait analysis data. Surgical recommendations were also recorded by the surgeons before and after consideration of the gait analysis data. Frequencies of pathology and surgery identification with and without gait analysis were compared using Fisher's exact test, and percent change in pathology and surgery identification was calculated. RESULTS: Pathology identification often changed for common gait problems including crouch (28% of cases), tibial rotation (35%), pes valgus (18%), excessive hip flexion (70%), and abnormal femur rotation (75%). Recognition of excessive hip flexion and abnormal femur rotation increased significantly after consideration of gait analysis data (p < 0.05). Surgical recommendations also frequently changed for the most common surgeries including tibial derotation osteotomy (30%), antero-lateral release (22%), plantar fascia release (33%), knee capsulotomy (25%), 1st metatarsal osteotomy (60%), and femoral derotation osteotomy (89%). At the patient level, consideration of gait analysis data altered surgical recommendations for 44% of patients. SIGNIFICANCE: Since gait analysis data often changes pathology identification and surgical recommendations, treatment decision making may be improved by including gait analysis in the patient care process.

Comparison of S2-Alar and traditional iliac screw pelvic fixation for pediatric neuromuscular deformity.

BACKGROUND CONTEXT: Many pelvic fixation options exist for posterior spinal fusion of pediatric neuromuscular scoliosis, including standard iliac screws (SISs) or a more recently introduced S2-Alar (S2A) technique. However, little data exist comparing the clinical and radiographic outcomes of these techniques. PURPOSE: This study aimed to dentify differences in clinical and radiographic outcomes for pediatric neuromuscular scoliosis patients treated with SIS or S2A pelvic fixation. STUDY DESIGN/SETTING: This was a retrospective cohort study at a pediatric orthopedic clinic. PATIENT SAMPLE: Patients aged 8-19 years undergoing posterior spinal fusion to the pelvis for neuromuscular scoliosis using SIS or S2A technique, with Gross Motor Function Classification System (GMFCS) Level 4 or 5 were included. OUTCOMES MEASURES: Postoperative complication rates associated with pelvic fixation method were the outcome measures. METHODS: Charts and radiographs were reviewed for demographics, intra- and postoperative course, levels of instrumentation, operative correction, and implant failure (IF). Postoperative complications were classified according to the Accordion scale. RESULTS: We studied 50 patients (28 SIS, 22 S2A) aged 14.0±2.8 years and an average follow-up of 3.5±1.7 years. The average number of levels fused was 16.5±1.1 with an average curve correction of 48°±21° postoperatively. A significant difference in radiographic IF rates was noted between SIS and S2A groups (57% vs. 27%, p=.02). No difference was noted between groups for frequency or severity of postoperative complications, inclusive of wound infections. Subgroup analysis demonstrated equivalent IF rates when comparing the S2A group with the SIS group with cross-links. CONCLUSIONS: The S2A group generally demonstrated improved rates of radiographic IF compared with the SIS group, but the rates became equivalent when a cross-link was added to an SIS construct. Further, no difference in postoperative complication rates were identified between SIS and S2A groups.

Rapid Diffusion and Nanosegregation of Hydrogen in Magnesium Alloys from Exposure to Water.

Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via D2O/D isotopic tracer and H2O exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at room temperature. Further, technologically important microalloying additions of <1 wt % Zr and Nd used to improve the manufacturability and mechanical properties of Mg significantly increased the extent of hydrogen ingress, whereas Al additions in the 2-3 wt % range did not. Segregation of hydrogen species was observed at regions of high Mg/Zr/Nd nanoprecipitate density and at Mg(Zr) metastable solid solution microstructural features. We also report evidence that this ingressed hydrogen was unexpectedly present in the alloy as nanoconfined, molecular H2. These new insights provide a basis for strategies to design Mg alloys to resist SCC in aqueous environments as well as potentially impact functional uses such as hydrogen storage where increased hydrogen uptake is desired.

Mutagenesis and computational docking studies support the existence of a histamine binding site at the extracellular ß3+ß3- interface of homooligomeric ß3 GABAA receptors.

Histamine is an important neurotransmitter that exerts its physiological actions through H1-4 metabotropic receptors in mammals. It also directly activates ionotropic GABAA receptor (GABAAR) ß3 homooligomers and potentiates GABA responses in αß heterooligomers in vitro, but the respective histamine binding sites in GABAARs are unknown. We hypothesized that histamine binds at the extracellular ß+ß- interface at a position homologous to the GABA binding site of heterooligomeric GABAARs. To test this, we individually mutated several residues at the putative ligand binding minus side of a rat GABAAR ß3 wild type subunit and of a ß3 subunit that was made insensitive to trace Zn(2+) inhibition [ß3(H267A); called (Z)ß3]. (Z)ß3, (Z)ß3(Y62L), (Z)ß3(Q64A), (Z)ß3(Q64E), α1(Z)ß3, or α1(Z)ß3(Y62L) receptors were studied in HEK293T cells using whole cell voltage clamp recording. ß3, ß3(Y62C), ß3(Q64C), ß3(N41C), ß3(D43C), ß3(A45C) or ß3(M115C) receptors were examined in Xenopus oocytes using two-electrode voltage clamp. Histamine directly activated (Z)ß3 and ß3 homooligomers and potentiated GABA actions in α1(Z)ß3 heterooligomers. Receptors containing (Z)ß3(Y62L), ß3(Y62C) and ß3(D43C) showed markedly reduced histamine potency, but homo- and heterooligomers with (Z)ß3(Q64E) exhibited increased potency. The GABAAR αß(γ) competitive antagonist bicuculline elicited sub-maximal agonist currents through (Z)ß3 homooligomers, the potency of which was strongly decreased by (Z)ß3(Y62L). Mutations ß3(N41C), ß3(A45C) and ß3(M115C) disturbed receptor expression or assembly. Computational docking into the crystal structure of homooligomeric ß3 receptors resulted in a histamine pose highly consistent with the experimental findings, suggesting that histamine activates ß3 receptors via a site homologous to the GABA site in αßγ receptors.

Utility of early postoperative radiographs after posterior spinal fusion for adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective. OBJECTIVE: Evaluate the ability of serial full-length spine radiographs to detect clinically significant implant-related (IR) and non-implant-related (NIR) radiographical abnormalities in the first 6 months after routine posterior spinal fusion for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Patients with AIS are exposed to repeated doses of ionizing radiation during the course of their treatment with potential consequences for their long-term health. Postoperative algorithms for AIS often involve frequent standing plain radiographs during the first 6 months after surgery to detect IR and NIR abnormalities that may impact a patient's clinical course. However, the actual clinical utility of such repeated spine radiographs has not been studied. METHODS: Retrospective chart and radiographical review was conducted at a single institution for patients with AIS after posterior spinal fusion between 2007 and 2012. Radiographical abnormalities identified on full-length spine radiographs or additional imaging modalities in the first 6 postoperative months were grouped into IR or NIR findings. The findings were considered clinically significant if they resulted in a deviation from an anticipated postoperative course or additional interventions. RESULTS: For 129 patients, 761 full-length spine radiographs were obtained in the first 6 postoperative months. Eight patients (11 radiographs) had IR or NIR abnormalities, with only 2 of these considered clinically significant. Seven of the remaining 121 were identified to have IR or NIR abnormalities using other imaging modalities, with 2 considered clinically significant. The sensitivity and specificity of a full-length spine radiograph for detecting a clinically significant abnormality was 50% and 95%, respectively. CONCLUSION: Routine full-length spine radiographs used with high frequency in the first 6 months after posterior spinal fusion rarely detected a radiographical abnormality that resulted in a meaningful change to a patient's clinical management. Blanket postoperative screening algorithms should be reconsidered to minimize patient radiation exposure.

Loss in spinal motion from inclusion of a single midlumbar level in posterior spinal fusion for adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective study. OBJECTIVE: Evaluate the impact of the distal fusion level on overall spine motion in patients with adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: In the surgical treatment of adolescent idiopathic scoliosis, the impact of incorporating a single additional distal lumbar fusion level on residual spinal motion is unclear. This study uses radiographs and computerized motion capture technology to determine whether the addition of a single lumbar level in a posterior fusion construct produces a detectable alteration in spinal motion. METHODS: Twenty-three patients with adolescent idiopathic scoliosis were evaluated with standing radiographs and computerized motion analysis preoperatively and 1 year after fusion. Patients were divided into 2 groups: L1-L2 group (distal fusion ended at L1-L2) and an L3 group (distal fusion ended at L3). Cobb angle, coronal vertical alignment, sagittal vertical alignment, thoracic kyphosis, and lumbar lordosis were measured from radiographs. Three-dimensional motion data were obtained for static standing and repeated bending or twisting motions. Statistical analysis was performed with Student t test, analysis of variance, and Fisher exact methods. RESULTS: Both the L1-L2 and L3 groups demonstrated loss of spinal motion compared with preoperative values. The L1-L2 group showed a significant loss of rotational motion but no significant loss of motion in the sagittal and coronal planes. The L3 group demonstrated significant loss of motion in both the coronal plane and the rotational plane. When the 2 groups were compared, the L3 group showed a significant loss of coronal plane bending (18° ± 10°, P = 0.002). CONCLUSION: Distal extension of a posterior spinal fusion construct to include L3 results in a significant decrease in spine motion in at least one plane. Preservation of a single lumbar segment may improve overall spine motion in the short term and may have implications for the long-term health of the unfused spine. LEVEL OF EVIDENCE: 3.

A comprehensive evaluation of the variation in ankle function during gait in children and youth with Charcot-Marie-Tooth disease.

A better understanding of gait dysfunction for children and youth with Charcot-Marie-Tooth (CMT) will assist in developing appropriate treatments and understanding prognosis for ambulation. The purpose of this retrospective study was to document the typical gait patterns in children and youth (12±4 years) with CMT using motion analysis and relate these findings back to the clinical assessment at the ankle. All patients underwent a motion analysis as a component of treatment decision-making. Lower extremity kinematics and kinetics were evaluated in comparison to a typically developing age-matched reference control group collected in the same gait laboratory. Three patient subgroups were defined based on peak ankle dorsiflexion in terminal stance: greater than typical (n=23), within typical range (n=30) and less than typical (n=13). The three subgroups showed statistically significant differences (p<0.004) in degree of impairment for ankle plantar flexor and dorsiflexor weakness and ankle plantar flexor contracture. Patients with excessive dorsiflexion in terminal stance had the greatest ankle plantar flexor weakness (median 2) and the greatest dorsiflexor weakness (median 4). Patients with less than typical dorsiflexion in terminal stance were the only patients with a plantar flexor contracture (-2±9°). Delayed peak dorsiflexion in stance was the most common kinematic finding and consistent with ankle plantar flexor weakness. All patients showed significantly less (p<0.001) peak ankle moments and power generation in terminal stance than the typically developing controls. We concluded that children and youth with CMT present differently in terms of impairment and associated gait issues which therefore require patient specific treatment strategies.

Histamine-gated ion channels in mammals?

There is ample pharmacological and physiological evidence for yet unidentified histamine receptors in mammalian brain that are linked to a Cl(-) conductance. In invertebrates, two histamine-gated chloride channels (HisCl α1 and α2) are already well known. HisCl channels are members of the Cys-loop receptor superfamily of ligand-gated ion channels and are closely related to the mammalian GABA(A) and glycine receptors (GlyR). Indeed, they share particularly strong homology within the ligand binding and ion channel domains. Here we discuss the possibility that mammalian HisCl channels might exist among the known GABA(A) or GlyR subunits. Studies published to date support this hypothesis, including evidence for direct histamine gating of GABA(A) ß homomers, histamine potentiation of GABA(A) αß and αßγ heteromeric receptors, and GABA(A) receptor blockade by some antihistamines. We explore what is known about the binding-site structure, function and pharmacology of invertebrate HisCl channels and other histamine binding sites to support and inform a broader search for HisCl channels among the mammalian GABA(A) and GlyR subunits. The discovery and identification of HisCl-like channels in mammals would not only enhance understanding of inhibitory signaling and histamine function in the mammalian brain, but also provide new avenues for development of therapeutic compounds targeting this novel histamine site. This commentary is therefore intended to foster consideration of a novel and potentially important target of histamine and histaminergic drugs in the CNS.

Mini-C-arm fluoroscopy for emergency-department reduction of pediatric forearm fractures.

BACKGROUND: Reduction of pediatric forearm fractures with the patient under sedation in the emergency department is a common practice throughout the United States. We hypothesized that the use of a mini-c-arm fluoroscopy device as an alternative to routine radiographs for evaluation of fracture reduction would (1) allow a more anatomic fracture reduction, (2) decrease the number of repeat reductions or subsequent procedures, (3) reduce overall radiation exposure to the patient, and (4) decrease the orthopaedic consultation time in the emergency department. METHODS: A retrospective cohort analysis of 279 displaced forearm and wrist fractures treated with closed reduction and casting with the patient under sedation in the emergency department of a level-I pediatric trauma center was performed, and the data were compared with historical controls. One hundred and thirteen fracture reductions were assessed with a mini-c-arm device, and 166 fracture reductions were evaluated with radiographs. All patients had radiographs of the injury. Blinded, independent reviewers graded the quality of reduction for residual angulation and translation of the reduced fracture. Radiation exposure was determined by the average number of radiographs made through either modality. Emergency department and outpatient charts were reviewed to determine the total orthopaedic consultation time and the need for repeat reductions or operative intervention. RESULTS: Pediatric forearm fractures undergoing closed reduction with assistance of the mini c-arm had a significant improvement in reduction quality (average angulation [and standard deviation], 6° ± 4° vs. 8 ± 6°; p = 0.02), a decrease in repeat fracture reduction and need for subsequent operative treatment (two [2%] of 113 fractures vs. fourteen [8.4%] of 166 fractures; p = 0.0001), and a decrease in radiation exposure to the patient (mean, 14.0 ± 10.3 mrem vs. 50.0 ± 12.7 mrem). The average orthopaedic consultation time was decreased with use of a mini c-arm (28 ± 12 min vs. 47 ± 19 min, p < 0.001). CONCLUSIONS: Use of the mini c-arm to assist in the closed reduction of pediatric forearm and wrist fractures in the emergency department can improve the quality of the reduction, decrease the radiation exposure to the patient, and decrease the need for repeat fracture reduction or additional procedures. Mini-c-arm imaging can also decrease the average orthopaedic consultation time for fracture reduction.

Orthopedic management of spina bifida.

The management of orthopedic problems in spina bifida has seen a dramatic change over the past 10 years. The negative effects of spasticity, poor balance, and the tethered cord syndrome on ambulatory function are better appreciated. There is less emphasis on the hip radiograph and more emphasis on the function of the knee and the prevention of knee pain. The importance of the hip abductor muscle and its influence on gait and knee function has been realized. Important developments in the treatment of spinal deformity include the use of pedicle screws which allow better correction. The role of anterior-only spinal surgery has been defined, which allows motion at the lumbo-sacral junction and has a lower postoperative infection rate than posterior surgery. Functional outcome assessments provide better feedback for surgeons and families in regards to which patients may benefit most from surgery. Overall, the past 10 years has seen the increased use of functional outcome measures such as Motion Analysis, oxygen consumption, and patient-based outcome assessments rather than traditional radiographic measures (e.g., hip dislocation or subluxation). This progress has resulted in a better understanding of spina bifida and, more importantly, improved outcomes for our patients. Additional research is likely to further enhance outcomes by establishing additional evidence-based interventions.

Low body mass index: a risk factor for superior mesenteric artery syndrome in adolescents undergoing spinal fusion for scoliosis.

STUDY DESIGN: Five cases of superior mesenteric artery (SMA) syndrome occurred at our institution over a 4-year period in adolescents undergoing spinal fusion surgery for scoliosis. All patients had in common a very slender body habitus. The measurement of body mass index (BMI) was low in all patients and an age-matched control group of patients undergoing similar surgery without this complication was assessed with this Index to determine its utility as a screening tool for this postoperative condition. OBJECTIVE: The goal was to determine if BMI is a useful parameter to assess the relative risk of patients undergoing spinal fusion surgery for developing the complication of SMA syndrome. BACKGROUND DATA: SMA syndrome is a serious and potentially fatal complication of spinal fusion surgery for scoliosis. Significant curve correction and slender body habitus have been cited in the literature as potential risk factors for this disorder. METHODS: BMI and the amount of scoliosis curve correction in the 5 patients developing SMA syndrome after spinal fusion were calculated and compared with those values in a group of 18 age-matched patients undergoing spinal fusion during the same time period. RESULTS: Absolute curve correction was comparable between the 2 groups. All 5 patients who developed SMA syndrome had a BMI of less than 18. CONCLUSIONS: Patients undergoing spinal fusion surgery for scoliosis with a BMI of less than 18 are at risk to develop SMA syndrome postoperatively.

Clinical and radiographic predictors of scoliosis in patients with myelomeningocele.

BACKGROUND: The prevalence of scoliosis in patients with myelomeningocele has been reported to be as high as 80% to 90% in some studies. However, those studies included patients with both congenital and developmental curves. The variation in the patient population as well as the definition of scoliosis in those studies made it difficult to predict the true prevalence of scoliosis in these patients. The purpose of the present study was to identify clinical and radiographic factors that may predict the onset of developmental scoliosis in patients with myelomeningocele. METHODS: A retrospective review of the charts and radiographs of all patients with a diagnosis of myelomeningocele who were seen in our clinic between 1990 and 1995 was performed. The criteria for inclusion in the study included a diagnosis of myelomeningocele or lipomeningocele, an age of more than ten years at the time of the review, serial documentation of motor power, and radiographic documentation of spinal deformity primarily in the coronal plane. The radiographs were examined to assess the degree of scoliosis and to document the last intact laminar arch. The relationship between the degree of scoliosis and the last intact laminar arch was evaluated. Statistical analysis was performed to assess the association between scoliosis and the clinical motor level, the ambulatory status, spasticity, motor asymmetry, and hip instability. RESULTS: One hundred and forty-one patients satisfied the criteria for inclusion in the study. Seventy-four patients (52%) had scoliosis. The average duration of follow-up was 9.4 years (range, three to thirty years), and the average age of the patients was nineteen years (range, ten to forty-two years). Scoliosis developed before the age of nine years in forty-three patients and after the age of nine years in thirty-one patients, with new curves continuing to develop until the age of fifteen years. Curves of <20 degrees degrees often resolved. The clinical motor level, ambulatory status, and last intact laminar arch were all found to be predictive factors for the development of scoliosis in these patients. CONCLUSIONS: In the population of patients with myelomeningocele, the term scoliosis should be reserved for curves of >20 degrees. New curves may continue to develop until the age of fifteen years. The level of the last intact laminar arch is a useful early predictor of the development of scoliosis in these patients.

Hardware complications in scoliosis surgery.

BACKGROUND: Scoliosis surgery has undergone a dramatic evolution over the past 20 years with the advent of new surgical techniques and sophisticated instrumentation. Surgeons have realized scoliosis is a complex multiplanar deformity that requires thorough knowledge of spinal anatomy and pathophysiology in order to manage patients afflicted by it. Nonoperative modalities such as bracing and casting still play roles in the treatment of scoliosis; however, it is the operative treatment that has revolutionized the treatment of this deformity that affects millions worldwide. As part of the evolution of scoliosis surgery, newer implants have resulted in improved outcomes with respect to deformity correction, reliability of fixation, and paucity of complications. Each technique and implant has its own set of unique complications, and the surgeon must appreciate these when planning surgery. MATERIALS AND METHODS: Various surgical techniques and types of instrumentation typically used in scoliosis surgery are briefly discussed. Though scoliosis surgery is associated with a wide variety of complications, only those that directly involve the hardware are discussed. The current literature is reviewed and several illustrative cases of patients treated for scoliosis at the Connecticut Children's Medical Center and the Newington Children's Hospital in Connecticut are briefly presented. CONCLUSION: Spine surgeons and radiologists should be familiar with the different types of instrumentation in the treatment of scoliosis. Furthermore, they should recognize the clinical and roentgenographic signs of hardware failure as part of prompt and effective treatment of such complications.