Ahmed A. Aoude

Methods to determine pedicle screw placement accuracy in spine surgery: a systematic review

Study designSystematic review.ObjectivesThe aims of this systematic review were: (1) to determine the most commonly used methods for assessing pedicle screw placement accuracy, and (2) assess the difference in pedicle screw placement accuracy between navigation and free-hand techniques according to the classification method.Background dataPedicle screw fixation and spine surgery have almost become synonymous. However, there is currently no gold standard method to assess pedicle screw placement accuracy. We reviewed the literature to determine current techniques used by spine surgeons for the assessment of pedicle screw accuracy.MethodsWe systematically reviewed the medical literature (OVID Medline, Embase, PubMed) to identify all articles published between 2010 and 2013 that have assessed pedicle screw placement accuracy in humans. Two independent reviewers with a third independent mediator performed study screening, selection and data extraction using a blinded and objective protocol.ResultsA total of 68 relevant articles were included in this systematic review, for a total of 3442 patients, 60 cadavers and 43,305 pedicle screws. The most widely used method (37 articles) was based on 2xa0mm breach increments measured on computer tomography images. The second most widely used method consisted of an “in” or “out” classification system (16 articles). The remaining 15 articles used variable classification systems. Our result suggests that an average of 91.4xa0% of pedicle screws placed with free-hand or fluoroscopy technique where within the safe zone (<2xa0mm breach) in comparison to an average of 97.3xa0% of pedicle screws using navigation (pxa0<xa00.001) for the 2xa0mm increment method. Similarly, the in or out classification also showed statistically significant difference between free-hand and navigated techniques (pxa0<xa00.001).ConclusionThe grading system based on 2xa0mm increments seems to be the most widely accepted method for determining pedicle screw placement accuracy. All grading systems were based on imaging alone without taking into account the direction of the breach or patient’s symptoms.

Automated Off-Line Respiratory Event Detection for the Study of Postoperative Apnea in Infants

Previously, we presented automated methods for thoraco-abdominal asynchrony estimation and movement artifact detection in respiratory inductance plethysmography (RIP) signals. This paper combines and improves these methods to give a method for the automated, off-line detection of pause, movement artifact, and asynchrony. Simulation studies demonstrated that the new combined method is accurate and robust in the presence of noise. The new procedure was successfully applied to cardiorespiratory signals acquired postoperatively from infants in the recovery room. A comparison of the events detected with the automated method to those visually scored by an expert clinician demonstrated a higher agreement (κ = 0.52) than that amongst several human scorers (κ = 0.31) in a clinical study . The method provides the following advantages: first, it is fully automated; second, it is more efficient than visual scoring; third, the analysis is repeatable and standardized; fourth, it provides greater agreement with an expert scorer compared to the agreement between trained scorers; fifth, it is amenable to online detection; and lastly, it is applicable to uncalibrated RIP signals. Examples of applications include respiratory monitoring of postsurgical patients and sleep studies.

Midterm Outcomes of the Recently FDA Approved Ceramic on Ceramic Bearing in Total Hip Arthroplasty Patients Under 65 Years of Age.

The present study aimed to evaluate the mid-term results of the fourth generation of ceramic on ceramic (CC) bearing. Demographics, surgical technique, complications, clinical and radiologic outcomes were analyzed in a series of 133 consecutive CC total hip arthroplasties (THAs) with a newest generation CC bearings to determine if these provide safe and well performing bearings. At the last follow-up, there were no cases of ceramic fracture or chipping and no revision surgery necessary for bearing related complication. One hip underwent two staged revision for infection and another underwent revision for dislocation, resulting in an overall 98.5% survival rate at a mean of 6 years. The newest generation of CC bearings provides a reliable and safe bearing in young, active patients undergoing THA.

Automated respiratory inductive plethysmography to evaluate breathing in infants at risk for postoperative apnea

Purpose: Although respiratory inductive plethysmography (RIP) is the method of choice for the assessment of sleep disordered breathing, it has not been applied to the study of infants at risk for postoperative apnea (POA). The purpose of this study was to apply RIP to evaluate breathing in these infants. An additional purpose was to implement, simultaneously, three novel algorithms to detect movement artifact, respiratory pauses, and thoracoabdominal asynchrony, since their combined output both detects respiratory pauses and classifies them as obstructive or central in origin.Methods: A prospective study design was employed to record the analogue output of RIP, saturation, and finger plethysmography in a convenience sample of infants. The data record underwent a dual analysis: 1) automated detection of respiratory events; and 2) visual coding of the cardiorespiratory data. A novel index, coined pause density, was calculated as the sum of all respiratory pauses.Results: Twenty infants, whose mean postconceptional ages and weights were 44.47±2.88 weeks and 4.21±0.99 kg, respectively, were recruited. Data recording ranged from four to 24 hr. Ten infants (term=5) experienced POA: central apnea=5, mixed obstructive apnea=6, and two former premature infants experienced both. Twenty-five central apneic events were detected, and the majority followed a sigh. Infants who experienced apnea also had high values of pause density.Conclusion: Respiratory inductive plethysmography may provide a useful method to evaluate breathing in infants at risk for POA. The study of short respiratory pauses may prove useful in predicting apnea risk.RésuméObjectif: Bien que la pléthysmographie inductive respiratoire (RIP) soit la méthode privilégiée pour évaluer les troubles respiratoires du sommeil, cette technique n’a pas été employée dans l’étude des nourrissons présentant un risque d’apnée postopératoire. L’objectif de cette étude était d’utiliser la RIP pour évaluer la respiration de ces nourrissons. Un objectif secondaire était de mettre en oeuvre trois nouveaux algorithmes pour détecter simultanément les artéfacts de mouvement, les pauses respiratoires et l’asynchronie thoraco-abdominale, étant donné que la combinaison de ces données détecte les pauses respiratoires et les classifie selon que leur origine soit obstructive ou centrale.Méthode: Un devis prospectif a été utilisé pour enregistrer la sortie analogique de la RIP, la saturation, et la pléthysmographie digitale dans un échantillon de commodité de nourrissons. Le fichier de données a subi une analyse double : 1) détection automatique des événements respiratoires ; et 2) codage visuel des données cardiorespiratoires. Un nouvel indicateur, appelé densité des pauses, qui est égal á la somme de toutes les pauses respiratoires, a été calculé.Résultats: Vingt nourrissons, dont l’âge post-conceptionnel et le poids moyen étaient respectivement de 44,47±2,88 semaines et 4,21±0,99 kg, ont été recrutés. L’enregistrement des données allait d’une durée de quatre à 24 h. Dix nourrissons (5 à terme) ont présenté une apnée postopératoire : apnée centrale=5, apnée mixte obstructive=6, et deux nourrissons nés prématurément ont présenté ces deux types d’apnée. Au total, 25 événements apnéiques centraux ont été détectés, et la majorité sont survenus à la suite d’un soupir. Chez les nourrissons ayant manifesté de l’apnée, nous avons également observé des valeurs élevées de densité des pauses.Conclusion: La pléthysmographie inductive respiratoire pourrait constituer une méthode utile pour évaluer la respiration des nourrissons présentant un risque d’apnée postopératoire. L’étude des courtes pauses respiratoires pourrait s’avérer utile pour prédire le risque d’apnée.

Thirty-Day Complications of Conventional and Computer-Assisted Total Knee and Total Hip Arthroplasty: Analysis of 103,855 Patients in the American College of Surgeons National Surgical Quality Improvement Program Database.

BACKGROUNDnComputer-assisted surgery (CAS) has gained popularity in orthopedics for both total knee arthroplasty (TKA) and total hip arthroplasty (THA) in the past decades.nnnMETHODSnThe American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients who underwent a primary, unilateral THA and TKA from 2011 to 2013. Multivariate analysis was conducted to compare the postoperative complications in patients whose surgery involved the use of CAS with those by conventional techniques.nnnRESULTSnWe identified 103,855 patients who had THA and TKA in the database between 2011 and 2013. There were higher overall adverse events (odds ratio [OR], 1.40; CI, 1.22-1.59), minor events (OR, 1.38; CI, 1.21-1.58), and requirements for blood transfusion (OR, 1.44; CI, 1.25-1.67) in the conventional group when compared with CAS for TKA. However, rate of reoperation was higher in the CAS group for TKA (OR, 1.60; CI, 1.15-2.25). The results also showed higher overall adverse events (OR, 2.61; CI, 2.09-3.26), minor events (OR, 2.82; CI, 2.24-3.42), and requirements for blood transfusion (OR, 3.41; CI, 2.62-4.44) in the conventional group when compared to CAS for THA. Nevertheless, superficial wound infections (OR, 0.46; CI, 0.26-0.81) were shown to be higher in the CAS group undergoing THA.nnnCONCLUSIONnThe use of CAS in THA and TKA reduced the number of minor adverse events in the first 30 days postoperatively. However, CAS was associated with an increased number of reoperations and superficial infections. The clinical benefits and disadvantages of CAS should be considered when determining the potential benefit-cost ratio of this technology.

Favorable Results of a Short, Tapered, Highly Porous, Proximally Coated Cementless Femoral Stem at a Minimum 4-Year Follow-Up

BACKGROUNDnShorter femoral stems have been increasingly used in total hip arthroplasty. However, there are few clinical studies evaluating the outcomes of these stems and comparing them to their regular-sized counterparts.nnnMETHODSnOur study provides radiologic and functional outcomes at 5-year mean follow-up of 131 cementless Tri-Lock Bone Preservation Stems, a short tapered stem with a proximal porous coating.nnnRESULTSnStem-related complications were low with one revision for stem aseptic loosening. Kaplan-Meier analysis estimated 99.2% stem survival rate at 5 years, comparable to conventional length Tri-Lock stems (99.8% at 8.9 years).nnnCONCLUSIONnThis study demonstrates that the Tri-Lock Bone Preservation Stem can provide successful outcomes at 5-year follow-up. Further studies are required to determine the long-term outcome of these implants in patients with poor bone stock.

Hypoalbuminaemia—a marker of malnutrition and predictor of postoperative complications and mortality after hip fractures

OBJECTIVEnOur aim was to determine the effect of hypoalbuminaemia as a marker of malnutrition on the 30-day postoperative complication rate and mortality in patients receiving surgical treatment for hip fractures using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.nnnMETHODSnWe analyzed all patients admitted with hip fractures receiving surgical treatment from 2011 to 2013. Patients were dichotomized based on their albumin levels; hypoalbuminaemia (albumin <3.5g/dL), and nonhypoalbuminaemia (albumin >3.5g/dL). Patient demographics, postoperative complications, and length of stay were analysed. Logistic regression analysis was conducted to assess the ability of albumin level for predicting postoperative complications, length of stay, and mortality.nnnRESULTSnA total of 10,117 patients with hip fractures were identified with 5414 patients with normal albumin levels, and 4703 with low albumin. Multivariate analysis showed that when controlling for comorbidities; hypoalbuminaemia alone was a predictor of postoperative complications (death, unplanned intubation, being on a ventilatoru2009>48h, sepsis, and blood transfusion), and increased length of stay (6.90±7.23 versus 8.44±8.70, CI 0.64-1.20, P<0.001).nnnCONCLUSIONnHypoalbuminaemia alone can predict postoperative outcomes in patients with hip fractures. Furthermore, patients with hypoalbuminaemia had a longer hospital length of stay. Further studies are needed to assess whether nutritional support can improve postoperative complications in patients with hypoalbuminaemia.

Clinical and Radiological Outcome of the Newest Generation of Ceramic-on-Ceramic Hip Arthroplasty in Young Patients

Ceramic-on-ceramic articulations have become an attractive option for total hip arthroplasty in young patients. In this study, we retrospectively evaluated the short- to midterm clinical and radiographic results in 51 consecutive patients (61 hips) using the newest generation of ceramic implants. Results obtained in our study showed positive clinical and radiological outcomes. Both HHS and UCLA activity scores doubled after surgery and tended to increase over time. There was one infection requiring a two-stage revision and a case of squeaking that began 2 years postoperatively after a mechanical fall. The overall survival rate of the implants was 98.4% at six years with revision for any reason as the end point. Based on these results, fourth generation ceramics offer a viable option for young and active patients.