Postoperative pain relief using intermittent intrapleural analgesia following thoracoscopic anterior correction for progressive adolescent idiopathic scoliosis

Background Thoracoscopic anterior scoliosis instrumentation is a safe and viable surgical option for corrective fusion of progressive adolescent idiopathic scoliosis (AIS) and has been performed at our centre on 205 patients since 2000. However, there is a paucity of literature reporting on or examining optimum methods of analgesia following this type of surgery. A retrospective study was designed to present the authors’ technique for delivering intermittent local anaesthetic boluses via an intrapleural catheter following thoracoscopic scoliosis surgery; report the pain levels that may be expected and any adverse effects associated with the use of intrapleural analgesia, as part of a combined postoperative analgesia regime. Methods Records for 32 patients who underwent thoracoscopic anterior correction for AIS were reviewed. All patients received an intrapleural catheter inserted during surgery, in addition to patient-controlled opiate analgesia and oral analgesia. After surgery, patients received a bolus of 0.25% bupivacaine every four hours via the intrapleural catheter. Patient’s perceptions of their pain control was measured using the visual analogue pain scale scores which were recorded before and after local anaesthetic administration and the quantity and time of day that any other analgesia was taken, were also recorded. Results 28 female and four male patients (mean age 14.5 ± 1.5 years) had a total of 230 boluses of local anaesthetic administered in the 96 hour period following surgery. Pain scores significantly decreased following the administration of a bolus (p < 0.0001), with the mean pain score decreasing from 3.66 to 1.83. The quantity of opiates via patient-controlled analgesia after surgery decreased steadily between successive 24 hours intervals after an initial increase in the second 24 hour period when patients were mobilised. One intrapleural catheter required early removal due to leakage; there were no other associated complications with the intermittent intrapleural analgesia method. Conclusions Local anaesthetic administration via an intrapleural catheter is a safe and effective method of analgesia following thoracoscopic anterior scoliosis correction. Post-operative pain following anterior thoracic scoliosis surgery can be reduced to ‘mild’ levels by combined analgesia regimes. Keywords: Adolescent idiopathic scoliosis; Thoracoscopic anterior spinal fusion; Anterior fusion; Intrapleural analgesia; Endoscopic anterior surgery; Pain relief; Scoliosis surgery

Is intermittent intrapleural analgesia safe and effective following thoracoscopic anterior scoliosis correction surgery?

Introduction: Thoracoscopic anterior instrumented fusion (TASF) is a safe and viable surgical option for corrective stabilisation of progressive adolescent idiopathic scoliosis (AIS) [1-2]. However, there is a paucity of literature examining optimum methods of analgesia following this type of surgery. The aim of this study was to identify; if local anaesthetic bolus via an intrapleural catheter provides effective analgesia following thoracoscopic scoliosis correction; what pain levels may be expected; and any adverse effects associated with the use of intermittent intrapleural analgesia at our centre. Methods: A subset of the most recent 80 patients from a large single centre consecutive series of 201 patients (April 2000 to present) who had undergone TASF had their medical records reviewed. 32 patients met the inclusion criteria for the analysis (i.e. pain scores must have been recorded within the hour prior and within two hours following an intrapleural bolus being given). All patients received an intrapleural catheter inserted during surgery, in addition to patient-controlled opiate analgesia and oral analgesia as required. After surgery, patients received a bolus of 0.25% bupivacaine every four hours via the intrapleural catheter. Visual analogue pain scale scores were recorded before and after the bolus of local anaesthetic and the quantity and time of day that any other analgesia was taken, were also recorded. Results and Discussion: 28 female and four male patients (mean age 14.5 ± 1.5 years) had a total of 230 boluses of local anaesthetic administered intrapleurally, directly onto the spine, in the 96 hour period following surgery. Pain scores significantly decreased following the administration of a bolus (p<0.0001), with the mean pain score decreasing from 3.66 to 1.83. The quantity of opiates via patient-controlled analgesia after surgery decreased steadily between successive 24 hours intervals after an initial increase in the second 24 hour period when patients were mobilised. One intrapleural catheter required early removal at 26 hours postop due to leakage; there were no other associated complications with the intermittent intrapleural analgesia method. Post-operative pain following anterior scoliosis correction was decreased significantly with the administration of regular local anaesthetic boluses and can be reduced to ‘mild’ levels by combined analgesia regimes. The intermittent intrapleural analgesia method was not associated with any adverse events or complications in the full cohort of 201 patients.

Book review: ‘Anterior Eye Disease and Therapeutics A-Z' [2nd ed.] Edition, by A. Bruce and M. Loughnan. Churchill Livingstone (Elsevier), Edinburgh 2011

With the ever-increasing emphasis on ocular disease recognition in the practice of optometry and especially anterior eye disease management and therapeutics, any book addressing such issues is bound to have a captive audience. This second edition of Anterior Eye Disease and Therapeutics A–Z provides a succinct yet comprehensive coverage of this topic.

A biomechanical analysis of anterior instrumentation used in the surgical correction of adolescent idiopathic scoliosis

Scoliosis is a deformity of the spine which affects children and adolescents, and remains a challenge to treat. This study measured the forces used during surgery to correct scoliosis and studied changes to spinal mechanics from the implantation of metal rods used to hold the spine straight. The results of this study will help surgeons and engineers understand how to straighten the spine more efficiently to provide patients with better outcomes.

Anterior temporal cortex and semantic memory : reconciling findings from neuropsychology and functional imaging

Studies of semantic impairment arising from brain disease suggest that the anterior temporal lobes are critical for semantic abilities in humans; yet activation of these regions is rarely reported in functional imaging studies of healthy controls performing semantic tasks. Here, we combined neuropsychological and PET functional imaging data to show that when healthy subjects identify concepts at a specific level, the regions activated correspond to the site of maximal atrophy in patients with relatively pure semantic impairment. The stimuli were color photographs of common animals or vehicles, and the task was category verification at specific (e.g., robin), intermediate (e.g., bird), or general (e.g., animal) levels. Specific, relative to general, categorization activated the antero-lateral temporal cortices bilaterally, despite matching of these experimental conditions for difficulty. Critically, in patients with atrophy in precisely these areas, the most pronounced deficit was in the retrieval of specific semantic information.

Persistent anterior chamber silicone oil and myopia

A 60-year-old male experienced a marked unilateral myopic shift of 20 D following attempted removal of intravitreal heavy silicone oil (HSO) used in the treatment of inferior proliferative vitreous retinopathy following retinal detachment. Examination revealed HSO adherent to the corneal endothelium forming a convex interface with the aqueous, obscuring the entire pupil, which required surgical intervention to restore visual acuity. This case highlights the potential ocular complications associated with silicone oil migration into the anterior chamber, which include corneal endothelial decompensation and a significant increase in myopia.

Electromyography and sonomyography analysis of the tibialis anterior: a cross sectional study

Background Foot dorsiflexion plays an essential role in both controlling balance and human gait. Electromyography (EMG) and sonomyography (SMG) can provide information on several aspects of muscle function. The aim was to establish the relationship between the EMG and SMG variables during isotonic contractions of foot dorsiflexors. Methods Twenty-seven healthy young adults performed the foot dorsiflexion test on a device designed ad hoc. EMG variables were maximum peak and area under the curve. Muscular architecture variables were muscle thickness and pennation angle. Descriptive statistical analysis, inferential analysis and a multivariate linear regression model were carried out. The confidence level was established with a statistically significant p-value of less than 0.05. Results The correlation between EMG variables and SMG variables was r = 0.462 (p < 0.05). The linear regression model to the dependent variable “peak normalized tibialis anterior (TA)” from the independent variables “pennation angle and thickness”, was significant (p = 0.002) with an explained variance of R2 = 0.693 and SEE = 0.16. Conclusions There is a significant relationship and degree of contribution between EMG and SMG variables during isotonic contractions of the TA muscle. Our results suggest that EMG and SMG can be feasible tools for monitoring and assessment of foot dorsiflexors. TA muscle parameterization and assessment is relevant in order to know that increased strength accelerates the recovery of lower limb injuries.

Monitoring changes of the tibialis anterior during dorsiflexion with electromyography, sonomyography, dynamometry and kinematic signals

Dorsiflexion (DF) of the foot plays an essential role in both controlling balance and human gait. Electromyography and Sonomyography can provide information on several aspects of muscle function. The aim was to describe a new method for real-time monitoring of muscular activity, as measured using EMG, muscular architecture, as measured using SMG, force, as measured using dynamometry, and kinematic parameters, as measured using IS during isometric and isotonic contractions of the foot DF. The present methodology may be clinically relevant because it involves a reproducible procedure which allows the function and structure of the foot DF to be monitored.

Classic identity negative priming involves accessing semantic representations in the left anterior temporal cortex

Classic identity negative priming (NP) refers to the finding that when an object is ignored, subsequent naming responses to it are slower than when it has not been previously ignored (Tipper, S.P., 1985. The negative priming effect: inhibitory priming by ignored objects. Q. J. Exp. Psychol. 37A, 571-590). It is unclear whether this phenomenon arises due to the involvement of abstract semantic representations that the ignored object accesses automatically. Contemporary connectionist models propose a key role for the anterior temporal cortex in the representation of abstract semantic knowledge (e.g., McClelland, J.L., Rogers, T.T., 2003. The parallel distributed processing approach to semantic cognition. Nat. Rev. Neurosci. 4, 310-322), suggesting that this region should be involved during performance of the classic identity NP task if it involves semantic access. Using high-field (4 T) event-related functional magnetic resonance imaging, we observed increased BOLD responses in the left anterolateral temporal cortex including the temporal pole that was directly related to the magnitude of each individual's NP effect, supporting a semantic locus. Additional signal increases were observed in the supplementary eye fields (SEF) and left inferior parietal lobule (IPL).

Partial intervertebral fusion secures successful outcomes after thoracoscopic anterior scoliosis correction: A low-dose computed tomography study

Study Design Retrospective review of prospectively collected data. Objectives To analyze intervertebral (IV) fusion after thoracoscopic anterior spinal fusion (TASF) and explore the relationship between fusion scores and key clinical variables. Summary of Background Information TASF provides comparable correction with some advantages over posterior approaches but reported mechanical complications, and their relationship to non-union and graft material is unclear. Similarly, the optimal combination of graft type and implant stiffness for effecting successful radiologic union remains undetermined. Methods A subset of patients from a large single-center series who had TASF for progressive scoliosis underwent low-dose computed tomographic scans 2 years after surgery. The IV fusion mass in the disc space was assessed using the 4-point Sucato scale, where 1 indicates <50% and 4 indicates 100% bony fusion of the disc space. The effects of rod diameter, rod material, graft type, fusion level, and mechanical complications on fusion scores were assessed. Results Forty-three patients with right thoracic major curves (mean age 14.9 years) participated in the study. Mean fusion scores for patient subgroups ranged from 1.0 (IV levels with rod fractures) to 2.2 (4.5-mm rod with allograft), with scores tending to decrease with increasing rod size and stiffness. Graft type (autograft vs. allograft) did not affect fusion scores. Fusion scores were highest in the middle levels of the rod construct (mean 2.52), dropping off by 20% to 30% toward the upper and lower extremities of the rod. IV levels where a rod fractured had lower overall mean fusion scores compared to levels without a fracture. Mean total Scoliosis Research Society (SRS) questionnaire scores were 98.9 from a possible total of 120, indicating a good level of patient satisfaction. Conclusions Results suggest that 100% radiologic fusion of the entire disc space is not necessary for successful clinical outcomes following thoracoscopic anterior selective thoracic fusion.

Quantifying progressive anterior overgrowth in the thoracic vertebrae of adolescent idiopathic scoliosis patients

Study design Anterior and posterior vertebral body heights were measured from sequential MRI scans of adolescent idiopathic scoliosis (AIS) patients and healthy controls. Objective To measure changes in vertebral body height over time during scoliosis progression to assess how vertebral body height discrepancies change during growth. Summary of background data Relative anterior overgrowth has been proposed as a potential driver for AIS initiation and progression. This theory proposes that the anterior column grows faster, and the posterior column slower, in AIS patients when compared to healthy controls. There is disagreement in the literature as to whether the anterior vertebral body heights are proportionally greater than posterior vertebral body heights in AIS patients when compared to healthy controls. To some extent, these discrepancies may be attributed to methodological differences. Methods MRI scans of the major curve of 21 AIS patients (mean age 12.5 ± 1.4 years, mean Cobb 32.2 ± 12.8º) and between T4 and T12 of 21 healthy adolescents (mean age 12.1 ± 0.5 years) were captured for this study. Of the 21 AIS patients, 14 had a second scan on average 10.8 ± 4.7 months after the first. Anterior and posterior vertebral body heights were measured from the true sagittal plane of each vertebra such that anterior overgrowth could be quantified. Results The difference between anterior and posterior vertebral body height in healthy, non-scoliotic children was significantly greater than in AIS patients with mild to moderate scoliosis. However there was no significant relationship between the overall anterior-posterior vertebral body height difference in AIS and either severity of the curve or its progression over time. Conclusions Whilst AIS patients have a proportionally longer anterior column than non-scoliotic controls, the degree of anterior overgrowth was not related to the rate of progression or the severity of the scoliotic curve.

Diurnal variation of anterior scleral and conjunctival thickness

Purpose To examine whether anterior scleral and conjunctival thickness undergoes significant diurnal variation over a 24-hour period. Methods Nineteen healthy young adults (mean age 22 ± 2 years) with minimal refractive error (mean spherical equivalent refraction -0.08 ± 0.39 D), had measures of anterior scleral and conjunctival thickness collected using anterior segment optical coherence tomography (AS-OCT) at seven measurement sessions over a 24-hour period. The thickness of the temporal anterior sclera and conjunctiva were determined at 6 locations (each separated by 0.5 mm) at varying distances from the scleral spur for each subject at each measurement session. Results Both the anterior sclera and conjunctiva were found to undergo significant diurnal variations in thickness over a 24-hour period (both p <0.01). The sclera and conjunctiva exhibited a similar pattern of diurnal change, with a small magnitude thinning observed close to midday, and a larger magnitude thickening observed in the early morning immediately after waking. The amplitude of diurnal thickness change was larger in the conjunctiva (mean amplitude 69 ± 29 μm) compared to the sclera (21 ± 8 μm). The conjunctiva exhibited its smallest magnitude of change at the scleral spur location (mean amplitude 56 ± 17 μm) whereas the sclera exhibited its largest magnitude of change at this location (52 ± 21 μm). Conclusions This study provides the first evidence of diurnal variations occurring in the thickness of the anterior sclera and conjunctiva. Studies requiring precise measures of these anatomical layers should therefore take time of day into consideration. The majority of the observed changes occurred in the early morning immediately after waking and were of larger magnitude in the conjunctiva compared to the sclera. Thickness changes at other times of the day were of smaller magnitude and generally not statistically significant.

Response of the anterior sclera to accommodation in myopes and emmetropes

• The biomechanical properties of the sclera are documented to be altered in eyes with myopia, with the myopic sclera thought to be more susceptible to deformation from otherwise normal ocular forces. • The close anatomical and functional relationship between the ciliary body and sclera suggests that ciliary muscle contraction during accommodation may influence the overlying sclera. • This study aimed to characterise the changes occurring in anterior scleral thickness with accommodation using anterior segment optical coherence tomography (AS-OCT) in young adult myopes and emmetropes.

The genetic associations of acute anterior uveitis and their overlap with the genetics of ankylosing spondylitis

Acute anterior uveitis (AAU) involves inflammation of the iris and ciliary body of the eye. It occurs both in isolation and as a complication of ankylosing spondylitis (AS). It is strongly associated with HLA-B*27, but previous studies have suggested that further genetic factors may confer additional risk. We sought to investigate this using the Illumina Exomechip microarray, to compare 1504 cases with AS and AAU, 1805 with AS but no AAU and 21 133 healthy controls. We also used a heterogeneity test to test the differences in effect size between AS with AAU and AS without AAU. In the analysis comparing AS+AAU+ cases versus controls, HLA-B*27 and HLA-A*02:01 were significantly associated with the presence of AAU (P<10−300 and P=6 × 10−8, respectively). Secondary independent association with PSORS1C3 (P=4.7 × 10−5) and TAP2 (P=1.1 × 10−5) were observed in the major histocompatibility complex. There was a new suggestive association with a low-frequency variant at zinc-finger protein 154 in the AS without AAU versus control analysis (zinc-finger protein 154 (ZNF154), P=2.2 × 10−6). Heterogeneity testing showed that rs30187 in ERAP1 has a larger effect on AAU compared with that in AS alone. These findings also suggest that variants in ERAP1 have a differential impact on the risk of AAU when compared with AS, and hence the genetic risk for AAU differs from AS.