Rupture, reconstruction, and rehabilitation: A multi-disciplinary review of mechanisms for central nervous system adaptations following anterior cruciate ligament injury.

BACKGROUND: Despite surgical reconstruction and extensive rehabilitation, persistent quadriceps inhibition, gait asymmetry, and functional impairment remain prevalent in patients after anterior cruciate ligament (ACL) injury. A combination of reports have suggested underlying central nervous system adaptations in those after injury govern long-term neuromuscular impairments. The classic assumption has been to attribute neurophysiologic deficits to components of injury, but other factors across the continuum of care (e.g. surgery, perioperative analgesia, and rehabilitative strategies) have been largely overlooked. OBJECTIVE: This review provides a multidisciplinary perspective to 1) provide a narrative review of studies reporting neuroplasticity following ACL injury in order to inform clinicians of the current state of literature and 2) provide a mechanistic framework of neurophysiologic deficits with potential clinical implications across all phases of injury and recovery (injury, surgery, and rehabilitation) RESULTS: Studies using a variety of neurophysiologic modalities have demonstrated peripheral and central nervous system adaptations in those with prior ACL injury. Longitudinal investigations suggest neurophysiologic changes at spinal-reflexive and corticospinal pathways follow a unique timecourse across injury, surgery, and rehabilitation. CONCLUSION: Clinicians should consider the unique injury, surgery, anesthesia, and rehabilitation on central nervous system adaptations. Therapeutic strategies across the continuum of care may be beneficial to mitigate maladaptive neuroplasticity in those after ACL injury.

Unplanned hospital admission after ambulatory surgery: a retrospective, single cohort study.

PURPOSE: We estimated the rate of unplanned hospital and intensive care unit (ICU) admissions following ambulatory surgery centre (ASC) procedures, and identified factors associated with their occurrence. METHODS: This retrospective cohort included adult patients who underwent ASC procedures within a large community practice from January 2010 to December 2014. Patients were categorized into two groups: unplanned postoperative hospital/ICU admission within 24 hr of procedure or uneventful discharge. Demographics, comorbidities, anesthesia type, procedure type, procedure group, and ASC facility were assessed. RESULTS: Of the 211,389 patients included, there were 211,147 uneventful discharges (99.89%) and 242 unplanned hospital admissions (0.11%), of which 75 were ICU admissions (0.04%). The multivariable logistic regression model for hospital admission showed an increased risk associated with age > 50 yr (odds ratio [OR], 1.53); American Society of Anesthesiologists (ASA) physical status (III vs II: OR, 1.45; IV vs II: OR, 1.88), comorbidity (chronic obstructive pulmonary disease: OR, 2.63; diabetes mellitus: OR, 1.62; transient ischemic attack: OR, 2.48) procedure (respiratory: OR, 2.92; digestive: OR, 2.66; musculoskeletal system: OR, 2.53), anesthetic management (general anesthesia [GA] and peripheral nerve block vs GA: OR, 1.79), and ASC facility (189BB: OR, 2.29; 30E9A: OR, 7.41; and BD21F: OR, 1.69). The multivariable logistic regression model for ICU admission showed increased risk of unplanned ICU admission associated with ASA physical status (ASA III vs II: OR, 3.0; ASA IV vs II: OR, 8.52), procedure (musculoskeletal system: OR, 2.45), and ASC facility (00E6C: OR, 3.14; 189BB: OR, 2.77; 30E9A: OR, 2.59; and BD21F: OR, 3.71). CONCLUSION: While a small percentage of adult patients who underwent ASC procedures required unplanned hospital admission (0.07%), approximately one-third of these admissions were to the ICU (0.04%). Facility was at least as strong a predictor of hospital admission as the patient- and/or procedure-specific variables.

RéSUMé: OBJECTIF: Nous avons estimé le taux d'admissions non planifiées à l'hôpital et à l'unité de soins intensifs (USI) après des interventions dans des centres de chirurgie ambulatoire (CCA), et identifié les facteurs associés à leur survenue. MéTHODE: Cette étude de cohorte rétrospective a porté sur des patients adultes ayant subi une intervention dans un CCA appartenant à une grande pratique communautaire entre janvier 2010 et décembre 2014. Les patients ont été catégorisés en deux groupes : admission postopératoire non planifiée à l'hôpital/USI dans les 24 h suivant l'intervention ou congé sans incident. Les données démographiques, les comorbidités, le type d'anesthésie, le type d'intervention, le groupe d'intervention et l'établissement de CCA ont été évalués. RéSULTATS: Parmi les 211 389 patients inclus, il y a eu 211 147 congés sans incident (99,89 %) et 242 admissions non planifiées à l'hôpital (0,11 %), 75 desquelles étaient des admissions à l'USI (0,04 %). Le modèle de régression logistique multivariée des admissions hospitalières a montré un risque accru associé à un âge > 50 ans (rapport de cotes [RC], 1,53); au statut physique ASA (American Society of Anesthesiologists) (III vs II : RC, 1,45; IV vs II : RC, 1,88), aux comorbidités (maladie pulmonaire obstructive chronique : RC, 2,63; diabète: RC, 1,62; accident ischémique transitoire : RC, 2,48); à l'intervention (respiratoire : RC, 2,92; digestive : RC, 2,66; appareil locomoteur : RC, 2,53); à la prise en charge anesthésique (anesthésie générale [AG] et bloc nerveux périphérique vs AG : RC, 1,79) et établissement de CCA (189BB : RC, 2,29; 30E9A : RC, 7,41; et BD21F : RC, 1,69). Le modèle de régression logistique multivariée des admissions à l'USI a montré un risque accru d'admission non planifiée à l'USI associé au statut physique ASA (ASA III vs II: RC, 3,0; ASA IV vs II: RC, 8,52), à l'intervention (appareil locomoteur : RC, 2,45), et à l'établissement de CCA (00E6C: RC, 3,14; 189BB: RC, 2,77; 30E9A: RC, 2,59; et BD21F: RC, 3,71). CONCLUSION: Alors qu'un faible pourcentage de patients adultes ayant subi des interventions en CCA ont nécessité une admission non planifiée à l'hôpital (0,11 %), environ un tiers de ces admissions étaient à l'USI (0,04 %). L'établissement était un prédicteur au moins aussi puissant d'admission à l'hôpital que les variables spécifiques au patient et/ou à l'intervention.

Neural activation for actual and imagined movement following unilateral hand transplantation: a case study.

Transplantation of a donor hand has been successful as a surgical treatment following amputation, but little is known regarding the brain mechanisms contributing to the recovery of motor function. We report functional magnetic resonance imaging (fMRI) findings for neural activation related to actual and imagined movement, for a 54-year-old male patient, who had received a donor hand transplant 50 years following amputation. Two assessments, conducted 3 months and 6 months post-operatively, demonstrate engagement of motor-control related brain regions for the transplanted hand, during both actual and imagined movement of the fingers. The intact hand exhibited a more intense and focused pattern of activation for actual movement relative to imagined movement, whereas activation for the transplanted hand was more widely distributed and did not clearly differentiate actual and imagined movement. However, the spatial overlap of actual-movement and imagined-movement voxels, for the transplanted hand, did increase over time to a level comparable to that of the intact hand. At these relatively early post-operative assessments, brain regions outside of the canonical motor-control networks appear to be supporting movement of the transplanted hand.

Regional Anesthesia for Ambulatory Anesthesiologists.

Proper pain control is critical for ambulatory surgery. Regional anesthesia can decrease postoperative pain, improve patient satisfaction, and expedite patient discharge. This article discusses the techniques, clinical pearls, and potential pitfalls associated with those blocks, which are most useful in an ambulatory perioperative setting. Interscalene, supraclavicular, infraclavicular, axillary, paravertebral, erector spinae, pectoralis, serratus anterior, transversus abdominis plane, femoral, adductor canal, popliteal, interspace between the popliteal artery and capsule of the knee, and ankle blocks are described.

Effect of Interscalene Brachial Plexus Block on the Pulmonary Function of Obese Patients: A Prospective, Observational Cohort Study.

BACKGROUND: The effect of interscalene block (ISB) on pulmonary function of obese participants has not been investigated. The goal of this study is to assess the association of obesity (body mass index [BMI] >29 kg/m vs BMI <25 kg/m) and change in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) after ISB in participants undergoing outpatient shoulder surgery. METHODS: This prospective, observational cohort study compared obese (BMI >29 kg/m) and normal-weight (BMI <25 kg/m) groups undergoing ISB for ambulatory shoulder surgery, on preblock and postblock FVC and FEV1, at 30 minutes postblock and in the postanesthesia care unit (PACU). The primary outcome in this study was FVC% change (percentage change from preblock to postblock values of FVC) at 30 minutes postblock in the supine position. Secondary outcomes included FVC% change at PACU and in the sitting position, FEV1% change (percentage change from preblock to postblock values of FEV1), FVC, FEV1, incidence of diaphragmatic paresis, modified Borg scale for perceived dyspnea, Richmond Agitation-Sedation Scale scores for sedation, and intraoperative airway events. RESULTS: Fourteen participants were recruited to each group. The mean (standard deviation) BMI in the normal-weight and obese groups was 23 (1.7) and 33 (3.1) kg/m, respectively. ISB success rate was 100%. All participants demonstrated hemidiaphragmatic paresis after ISB. Compared to the normal-weight group, in the sitting position, the obese group had a significant decrease in FVC% change at 30 minutes (-30 [10.5] vs -23 [7.2], P = .046) and an FEV1% change in the PACU (-40 [12.6] vs -27 [13.9], P = .02). No difference was found for measurements taken in the supine position. A repeated-measures analysis demonstrated that, adjusted for position, there is no significant group effect on FVC% change or FEV1% change from 30 minutes to PACU. The 2 groups were not different in terms of breathlessness and sedation at 30 minutes (P = .67, P = .48, respectively) and in the PACU (P = .69, P > .99, respectively) nor in the occurrence of intraoperative airway events (P > .99). CONCLUSIONS: ISB is associated with greater FVC and FEV1 reductions in obese participants undergoing shoulder surgery compared to normal-weight participants. Neither time (30 minutes versus PACU) nor position (sitting versus supine) affected this relationship. Despite these changes, obesity was not associated with increased clinical respiratory symptoms or events.

Changes in Brain Resting-state Functional Connectivity Associated with Peripheral Nerve Block: A Pilot Study.

BACKGROUND: Limited information exists on the effects of temporary functional deafferentation (TFD) on brain activity after peripheral nerve block (PNB) in healthy humans. Increasingly, resting-state functional connectivity (RSFC) is being used to study brain activity and organization. The purpose of this study was to test the hypothesis that TFD through PNB will influence changes in RSFC plasticity in central sensorimotor functional brain networks in healthy human participants. METHODS: The authors achieved TFD using a supraclavicular PNB model with 10 healthy human participants undergoing functional connectivity magnetic resonance imaging before PNB, during active PNB, and during PNB recovery. RSFC differences among study conditions were determined by multiple-comparison-corrected (false discovery rate-corrected P value less than 0.05) random-effects, between-condition, and seed-to-voxel analyses using the left and right manual motor regions. RESULTS: The results of this pilot study demonstrated disruption of interhemispheric left-to-right manual motor region RSFC (e.g., mean Fisher-transformed z [effect size] at pre-PNB 1.05 vs. 0.55 during PNB) but preservation of intrahemispheric RSFC of these regions during PNB. Additionally, there was increased RSFC between the left motor region of interest (PNB-affected area) and bilateral higher order visual cortex regions after clinical PNB resolution (e.g., Fisher z between left motor region of interest and right and left lingual gyrus regions during PNB, -0.1 and -0.6 vs. 0.22 and 0.18 after PNB resolution, respectively). CONCLUSIONS: This pilot study provides evidence that PNB has features consistent with other models of deafferentation, making it a potentially useful approach to investigate brain plasticity. The findings provide insight into RSFC of sensorimotor functional brain networks during PNB and PNB recovery and support modulation of the sensory-motor integration feedback loop as a mechanism for explaining the behavioral correlates of peripherally induced TFD through PNB.

New medications and techniques in ambulatory anesthesia.

Novel anesthetic and analgesic agents are currently under development or investigation to improve anesthetic delivery and patient care. The pharmacokinetic and analgesic profiles of these agents are especially tailored to meet the challenges of rapid recovery and opioid minimization associated with ambulatory anesthesia practice.

Long-acting serotonin antagonist (Palonosetron) and the NK-1 receptor antagonists: does extended duration of action improve efficacy?

In a growing outpatient surgical population, postdischarge nausea and vomiting (PDNV) is unfortunately a common and costly anesthetic complication. Identification of risk factors for both postoperative nausea and vomiting and PDNV is the hallmark of prevention and management. New pharmacologic interventions with extended duration of action, including palonosetron and aprepritant, may prove to be more efficacious.

Management of postdischarge nausea and vomiting after ambulatory surgery.

PURPOSE OF REVIEW: Although there are extensive studies of postoperative and postdischarge nausea and vomiting (PONV/PDNV) up to 24  h, few investigate 'delayed PDNV'. With an increasing outpatient surgical population, specific 'delayed PDNV' risk identification and management is necessary for improving outcomes and helping patients after discharge. This review will discuss possible PDNV specific risk factors, successful prevention and management of PDNV following ambulatory anesthesia and the principles and pharmacology of these interventions. RECENT FINDINGS: Current research has demonstrated beneficial PDNV management up to 72  h with the long-acting 5-hydroxytryptamine-3 receptor antagonist palonosetron. Neurokinin-1 antagonists have demonstrated superior antiemesis, but not antinausea compared with more traditional and less expensive options. Dexamethasone provides improvements in quality of recovery associated with improved PDNV outcomes. SUMMARY: Further PDNV specific research is needed, including PDNV predictive models in directing antiemetic interventions. Long-acting antiemetics and postdischarge oral antiemetics are effective in PDNV pharmacologic management. Neurokinin-1 receptor antagonists are effective in reducing the incidence of vomiting, but not nausea. The addition of nonpharmacologic interventions such as acustimulation may reduce PDNV. Multimodal analgesia including nonopioid analgesics and ambulatory continuous peripheral nerve blocks are encouraged to achieve adequate postoperative analgesia and reduce opioid induced PDNV.

Augmentation of occipitocervical contoured rod fixation with C1-C2 transarticular screws.

BACKGROUND CONTEXT: The technique of occipitocervical fusion using a threaded contoured rod attached with sublaminar wires to the occiput and upper cervical vertebrae is widely used throughout the world and has been clinically proven to provide effective fixation of the destabilized spine. However, this system has some disadvantages in maintaining stability, especially at C1-C2 because of the large amount of axial rotation at this level. In some clinical situations such as fracture of the C1 lamina, C1 laminectomy, and excessively lordotic curvature, it is not always possible to wire C1 directly into the construct. In such cases, combination of other stabilization methods that include C1 indirectly can be used to achieve a reliable posterior internal fixation. PURPOSE: Primarily, to evaluate whether a contoured rod construct in which C1 is indirectly included using C1-C2 transarticular screws is biomechanically equivalent to a standard, fully wired contoured rod construct. Secondarily, to evaluate the biomechanical benefit of adding C1-C2 transarticular screws to a fully wired contoured rod construct. STUDY DESIGN: Repeated-measures nondestructive in vitro biomechanical testing of destabilized cadaveric human occipitocervical spine specimens. METHODS: Six human cadaveric specimens from the occiput to C3 were studied. Angular and linear displacement data were recorded while nonconstraining nondestructive loads were applied. Three methods of fixation were tested: contoured rod incorporating C1 with and without transarticular screws and contoured rod with transarticular screws without incorporating C1. RESULTS: All three constructs reduced motion to well within normal range. In contoured rod constructs with C1 wired, addition of transarticular screws slightly but significantly improved stability. In constructs with transarticular screws, incorporation of C1 into the contoured rod wiring did not improve stability significantly. CONCLUSIONS: Adding C1-C2 transarticular screws to a wired contoured rod construct where C1 is included only slightly improves stability. As the absolute reduction in motion from adding transarticular screws is small (<1 degree), it is doubtful whether any enhanced fusion from this additional procedure outweighs the surgical risks. However, transarticular screws provide an effective alternate method to fixate C1 when the posterior arch of C1 is absent or has been fractured.

Biomechanical analysis of cranial settling after transoral odontoidectomy.

The authors conducted a biomechancial study to determine whether C-1 ring integrity is important in maintaining normal occiput-C-2 separation, specifically when the anterior arch is transected to provide access to the dens during an odontoidectomy procedure. Six human cadaveric occiput-C3 specimens were loaded under axial compression, and the bilateral horizontal separation of the C-1 lateral masses and the vertical compression of the occiput relative to C-2 were recorded. Specimens were first studied after odontoidectomy without C-1 ring transection, then after C-1 anterior arch transection, and finally after C-1 lamina transection. With applied compressive load corresponding to three times the weight of the head, the C-1 ring spread horizontally 1.57 +/- 0.30 mm more when the anterior arch of C-1 was transected than when left intact, resulting in 0.74 +/- 0.44 mm collapse in the occiput-C-2 vertical separation. After laminar transection, the C-1 ring spread 6.55 +/- 2.29 mm more than when it was intact. The resultant vertical separation was a 3.37 +/- 1.89-mm collapse in the occiput-C-2. All changes in C-1 spreading and the occiput-C-2 collapse were statistically significant (p < 0.05, paired Student's t-tests). The C-1 ring continuity prevents horizontal spreading caused by the wedging of C-1 between the occiput and C-2 and thus prevents cranial settling. Therefore, to prevent the subsequent development of disease related to cranial settling, the authors recommend that the surgeon resect part of C-1 only if necessary during odontoidectomy.