Allan Beebe

A preliminary study of volatile agents or total intravenous anesthesia for neurophysiological monitoring during posterior spinal fusion in adolescents with idiopathic scoliosis.

Study Design. A prospective randomized controlled trial. Objective. The purpose of this study was to prospectively compare the efficacy of neurophysiological monitoring during general anesthesia with either a total intravenous technique or with the volatile anesthetic agent, desflurane. Summary of Background Data. A total intravenous anesthetic technique is generally chosen when neurophysiological monitoring is used as it has been shown to facilitate such monitoring. Despite this, with prolonged infusions of propofol, prolonged awakening times may be seen, which may impact the time required for postoperative neurological assessment or more importantly result in significant delays, should a wake-up test become necessary. To date, there are no prospective trials comparing intravenous techniques with a volatile agent–based anesthetic technique and its effects on neurophysiological monitoring. Methods. This prospective study compares somatosensory evoked potential and motor evoked potential monitoring during posterior spinal fusion in 30 adolescents. The patients were randomized to receive a total intravenous technique with propofol-remifentanil or a volatile agent–based technique with desflurane-remifentanil. Results. The groups were similar with regard to age, weight, height, body mass index, Cobb angle, and distribution of Lenke classifications. No differences were noted in anesthesia time, surgery time, intraoperative fluids, or estimated blood loss between the 2 groups. Time to eye opening, time to following commands, and time to tracheal extubation were shorter in the volatile anesthesia group than the total intravenous anesthesia group. No clinically significant difference was noted in the amplitude or latency of somatosensory evoked potential monitoring. Although statistically significantly greater voltage amplitude was required to generate a motor evoked potential, the voltage amount was within a clinically acceptable range. Conclusion. Our data demonstrate that a volatile agent–based anesthetic regimen is feasible even during neurophysiological monitoring. Advantages include a more rapid awakening and the feasibility of a rapid wake-up test (<5 min) in the event that irreversible changes in neurophysiological monitoring are noted. Level of Evidence: 2

Accuracy of the CNAP monitor, a noninvasive continuous blood pressure device, in providing beat-to-beat blood pressure readings in the prone position

STUDY OBJECTIVE To assess the accuracy of a noninvasive continuous arterial pressure (CNAP) monitor in patients who are positioned prone in the operating room. DESIGN Prospective study. SETTING Operating room at a childrens hospital. PATIENTS 20 pediatric patients, aged 13.8 ± 2 years, and weight 63.7 ± 18.8 kg, scheduled for surgery in the prone position, and for which arterial catheter placement was planned. INTERVENTIONS Measurements were recorded with an arterial line (AL) and a new noninvasive continuous blood pressure (BP) monitor. MEASUREMENTS Systolic (SBP), diastolic (DBP), and mean arterial (MAP) pressure readings were captured from an arterial cannula and the CNAP device every minute during anesthesia. MAIN RESULTS The study cohort consisted of analysis of 4104 pairs of SBP, DBP, and MAP values, which showed an absolute difference between the AL and CNAP device readings of 7.9 ± 6.3 mmHg for SBP, 5.3 ± 4.3 mmHg for DBP, and 4.6 ± 3.9 mmHg for MAP. Bland-Altman analysis of MAP values showed a bias of 0.26 mmHg, with upper and lower limits of agreement of 12.18 mmHg and -11.67 mmHg, respectively. CNAP readings deviated from arterial values by ≤ 5 mmHg in 67% of MAP values, 59% of DBP values, and 43% of SBP readings. The difference was ≤ 10 mmHg for 94% of MAP readings, 90% of DBP values, and 73% of SBP readings. CONCLUSIONS During prone positioning, the CNAP monitor provided clinically acceptable accuracy for MAP values, similar to those reported in adults in the supine position.

A retrospective quality improvement study of ketorolac use following spinal fusion in pediatric patients.

BACKGROUND: There are studies and literature that support the claim that ketorolac use after spinal fusion in the adult population can increase the risk of pseudarthrosis, instrumentation failure, and/or nonunion. There is limited research when using ketorolac in the pediatric population, especially short-term use. METHODS: Chart review of 46 pediatric patients who had prior spinal fusions for scoliosis between July 2003 and August 2005. Twenty-five of the patients received ketorolac and 21 did not. The lengths of stay, incidence of curve progression, and/or incidence of nonunion or instrumentation failure were compared in the 2 groups. RESULTS: At the 1-year follow-up, 95% of the patients returned and at the 3-year follow-up, 52% of the patients returned and there was no clinical or radiographic evidence of curve progression, nonunion, or instrumentation failure. LEVEL OF EVIDENCE: This is a retrospective study looking at results of 2 patient groups. This is a level III study.

Bridge Plating Length-Unstable Pediatric Femoral Shaft Fractures.

The treatment of pediatric diaphyseal femur fractures, particularly length-unstable fractures, continues to be an area of controversy in patients from age 6 to skeletal maturity. Submuscular bridge plating is an alternative that allows for stable internal fixation while minimizing soft tissue disruption. We describe a surgical technique that has simplified both implantation and removal. This technique provides a stable construct in comminuted and unstable fracture patterns allowing for early mobilization with minimal complications.

Percutaneous Doxycycline Treatment of Juxtaphyseal Aneurysmal Bone Cysts.

Background: A recurrence rate of 19% to 23% has been reported in juxtaphyseal aneurysmal bone cysts (ABC) without en bloc resection or amputation. No percutaneous surgical techniques or drug treatments have demonstrated consistent bone healing with normal physeal growth and a recurrence rate of <19%. Doxycycline has properties that may make it an appropriate agent for percutaneous treatment of juxtaphyseal ABC in skeletally immature patients. Methods: We retrospectively reviewed 16 patients who underwent percutaneous treatment of ABCs with doxycycline from 2006 to 2011. The mean age was 7.1 years (range, 2 to 15 y). There were 16 treatment locations: humerus (9), tibia (3), fibula (2), femur (1), and ulna (1). Sixteen patients completed treatment involving 102 treatment sessions (2 to 14 sessions per patient). Treatment response was evaluated radiographically by measuring the lytic component, thickness of involved cortex, and signs of bony remodeling, and evidence of physeal growth arrest. Recurrence was indicated by new areas of lytic destruction after completion of treatment. The minimum follow-up was 18 months (mean, 39 mo). Results: All 16 patients demonstrated reduction in lytic destruction, bony healing, and bony remodeling. One patient demonstrated recurrent minimal lytic destruction after 20 months of observation. Seven patients (7/16, 44%) demonstrated physeal ABC involvement; 5 of 7 patients healed with a physeal bone bridge, all ⩽15% of the physeal surface area, 1 with mild central physeal deformity. All patients with focal transphyseal ABC involvement (4/4, 100%) demonstrated focal bone bridge after treatment. No patient had diffuse physeal growth arrest; only patients with intraphyseal or transphyseal ABC involvement had focal physeal growth arrest. Conclusions: In this series, patients undergoing percutaneous doxycycline treatment of juxtaphyseal ABCs demonstrated ABC healing and a recurrence rate of 6% at >18 months. Patients without physeal ABC involvement demonstrated no evidence of physeal growth arrest. Level of Evidence: Level IV—therapeutic study.

A Prospective, Open-Label Trial of Clevidipine for Controlled Hypotension During Posterior Spinal Fusion

OBJECTIVES Controlled hypotension is one means to limit or avoid the need for allogeneic blood products. Clevidipine is a short-acting, intravenous calcium channel antagonist with a half-life of 1 to 3 minutes due to rapid metabolism by non-specific blood and tissue esterases. To date, there are no prospective evaluations with clevidipine in the pediatric population. We prospectively evaluated the dosing requirements, efficacy, and safety of clevidipine for ontrolled hypotension during spinal surgery for neuromuscular scoliosis in the pediatric population. METHODS Patients undergoing posterior spinal fusion for neuromuscular scoliosis were eligible for inclusion. The study was an open label, observational study. Maintenance anesthesia included desflurane titrated to maintain a bispectral index at 40 to 60 and a remifentanil infusion. Motor and somatosensory evoked potentials were monitored intraoperatively. When the mean arterial pressure (MAP) was ≥ 65 mmHg despite remifentanil at 0.3 mcg/kg/min, clevidipine was added to maintain the MAP at 55 to 65 mmHg. Clevidipine was initiated at 0.25 to 1 mcg/kg/min and titrated up in increments of 0.25 to 1 mcg/kg/min every 3 to 5 minutes to achieve the desired MAP. RESULTS The study cohort included 45 patients. Fifteen patients (33.3%) did not require a clevidipine infusion to maintain the desired MAP range, leaving 30 patients including 13 males and 17 females for analysis. These patients ranged in age from 7.9 to 17.4 years (mean ± SD: 13.7 ± 2.2 years) and in weight from 18.9 to 78.1 kg (mean ± SD: 43.4 ± 14.2 kg). Intraoperatively, the clevidipine infusion was stopped in 6 patients as the surgeon expressed concerns regarding spinal cord perfusion and requested a higher MAP than the study protocol allowed. The data until that point were included for analysis. The target MAP was initially achieved at a mean time of 8.9 minutes. Sixteen of the 30 patients (53.3%) achieved the target MAP within 5 minutes. Heart rate (HR) increased from a baseline of 83 ± 16 to 86 ± 15 beats per minute (mean ± SD) (p=0.04) with the administration of clevidipine. No patient had a HR increase ≥ 20 beats per minute or required the administration of a β-adrenergic antagonist. The duration of the clevidipine administration varied from 8 to 527 minutes (mean ± SD: 160 ± 123 minutes). The maintenance infusion rate of clevidipine varied from 0.25 to 5.0 mcg/kg/min (mean ± SD: 1.4 ± 1.1 mcg/kg/min). Clevidipine was paused a total of 43 times in the 30 cases. In 18 of the 30 patients (60%), the clevidipine infusion was temporarily paused more than once due to a MAP < 55 mmHg. A fluid bolus was administered to only 1 patient to treat the low MAP. No patient required the administration of a vasoactive agent for hypotension. When the clevidipine infusion was discontinued as controlled hypotension was no longer required, the MAP returned to baseline or ≥ 65 mmHg within 10 minutes in 12 of the 30 patients (40%). CONCLUSIONS Clevidipine can be used to provide controlled hypotension during posterior spinal fusion. The response of the MAP, both the onset and duration of action, were rapid. Although titration of the infusion with occasional pauses of administration may be needed, excessive hypotension was not noted.

Is there still a place for cast wedging in pediatric forearm fractures

Background: Forearm fractures are common skeletal injuries in childhood and can usually be treated nonoperatively with closed reduction and casting. Trends toward increasing operative treatment of these fractures have emerged. We aim to demonstrate the safety and efficacy of cast wedging for treatment of pediatric forearm fractures. Methods: We performed a prospective chart review of patients with forearm fractures, including distal radius (DR) fractures, treated with cast wedging at a single large pediatric hospital from June 2011 to September 2012. Inclusion criteria specified open distal radial physis, closed injury, loss of acceptable reduction, and availability of clinical and radiographic data from injury to cast removal. Exclusion criteria included pathologic fractures, neurovascular injury, fracture dislocations, open fractures, and closed DR physis. Reductions were performed and patients followed according to standard protocol at our institution, including placement into long-arm casts, initial follow-up visit within 5 to 10 days postinjury, and weekly visits for 2 weeks thereafter. If alignment were deemed unacceptable within 3 weeks of injury, cast wedging was utilized. Radiographic measurements of alignment included both radius and ulna on the injury film, postreduction, prewedge, postwedge, and final films. Radiographic technique was standardized, with repeatability testing demonstrating a precision of ±2 degrees. Results: Over 15 months, our hospital treated 2124 forearm or DR fractures with closed reduction and casting. There were 60 fractures treated either with percutaneous fixation (36) or open treatment (24). A total of 79 forearm or DR fractures were treated with cast wedging secondary to loss of reduction, of which 70 patients had complete clinical and radiographic data. Average age was 8.4 years (range, 3 to 14 y), with 25 females and 45 males. Significant improvement in angulation for both-bone forearm fracture from prewedge to final films was seen in 69 children, with no major complications. One patient failed wedging and required surgical reduction and fixation. Conclusions: Cast wedging is a simple, safe, noninvasive, and effective method for treatment of excessive angulation in pediatric forearm fractures. Level of Evidence: Level IV.

Phenylephrine to Treat Hypoxemia during One-Lung Ventilation in a Pediatric Patient

To improve surgical visualization and facilitate the procedure, one-lung ventilation (OLV) is frequently used during thoracic surgery. Although generally well tolerated, the ventilation–perfusion inequality induced by OLV may lead to a decrease in oxygenation and, at times, hypoxemia. Effective treatment algorithms and strategies are necessary for the treatment of hypoxemia during OLV to ensure that the technique can be continued without interruption and allow for completion of the surgical procedure. Treatment strategies may include applying positive end expiratory pressure to the nonoperative lung, continuous positive airway pressure or low flow oxygen insufflation to the operative lung, decreasing anesthetic agents that interfere with hypoxic pulmonary vasoconstriction (HPV), or switching to total intravenous anesthesia. Although less commonly employed, α-adrenergic agonists may also improve oxygenation during OLV by augmenting HPV. We present a 12-year-old girl who developed hypoxemia during OLV, which was not corrected by the usual maneuvers. Hypoxemia was successfully treated with a phenylephrine infusion. The potential applications of α-adrenergic agonists such as phenylephrine in the treatment of hypoxemia during OLV are discussed and its physiologic basis reviewed.

Intraoperative Anaphylactic Reaction: Is it the Floseal?

When hemodynamic or respiratory instability occurs intraoperatively, the inciting event must be determined so that a therapeutic plan can be provided to ensure patient safety. Although generally uncommon, one cause of cardiorespiratory instability is anaphylactic reactions. During anesthetic care, these most commonly involve neuromuscular blocking agents, antibiotics, or latex. Floseal is a topical hemostatic agent that is frequently used during orthopedic surgical procedures to augment local coagulation function and limit intraoperative blood loss. As these products are derived from human thrombin, animal collagen, and animal gelatin, allergic phenomenon may occur following their administration. We present 2 pediatric patients undergoing posterior spinal fusion who developed intraoperative hemodynamic and respiratory instability following use of the topical hemostatic agent, Floseal. Previous reports of such reactions are reviewed, and the perioperative care of patients with intraoperative anaphylaxis is discussed.

Pediatric Diaphyseal Femur Fractures: Submuscular Plating Compared With Intramedullary Nailing

This study compared the radiographic and clinical outcomes of pediatric diaphyseal femur fractures treated by submuscular plating, flexible retrograde intramedullary nailing, or rigid antegrade intramedullary nailing with a trochanteric entry point in skeletally immature patients who were 8 years and older. A retrospective review was conducted of skeletally immature patients 8 years and older who were treated for femur fracture with submuscular plating, flexible intramedullary nailing, or rigid intramedullary nailing from 2001 to 2014 with a minimum 12-week follow-up. Treatment outcomes were compared for statistical significance, including time to union, malunion, nonunion, heterotopic ossification, avascular necrosis, time to full weight bearing, limb length discrepancy, residual limp, painful hardware, and infection. The study identified 198 femur fractures in 196 patients (mean age, 11.9 years). Each femur fracture was treated with submuscular plating (35), flexible intramedullary nailing (61), or rigid intramedullary nailing (102). Mean follow-up across the cohort was 48 weeks, ranging from 12 to 225 weeks. Flexible nailing was associated with an increased incidence of malunion (P<.0001) and hardware irritation (P=.0204) and longer time to full weight bearing (P=.0018). Rigid nailing was associated with an increased incidence of limp at 12-week followup (P=.0412). Additionally, 23.5% of patients who were treated with rigid nailing had heterotopic ossification. Of all surgical methods, submuscular plating allowed for the most rapid return to full weight bearing (mean, 7 weeks) and offered the fastest healing rate (mean, 6 weeks). Submuscular plating resulted in faster times to union and full weight bearing, with minimal complication rates. Rigid intramedullary nailing with trochanteric entry resulted in a lower incidence of malunion and hardware-related complications; however, these patients had an increased incidence of heterotopic ossification and residual limp postoperatively. Flexible retrograde intramedullary nailing resulted in the highest rates of malunion and hardware irritation and the longest time to full weight bearing. [Orthopedics. 2016; 39(6):353-358.].