Constantin Schizas

Pharmacological treatment of heterotopic ossification following hip and acetabular surgery

Heterotopic ossification is a common complication following total hip arthroplasty and surgery following acetabular trauma. It is associated with pain and a decreased range of movement. Prophylaxis is achieved by either non-steroidal anti-inflammatory drug treatment or localised irradiation therapy. The objective of this study was to evaluate the evidence for pharmacological agents used for the prophylaxis of heterotopic ossification following hip and acetabular surgery. The study used a comprehensive literature search to identify all major clinical studies investigating the pharmacological agents used in the prophylaxis of heterotopic ossification following hip and acetabular surgery. It was concluded that indometacin remains the ‘gold standard’ for heterotopic ossification prophylaxis following total hip arthroplasty and is the only drug proven to be effective against heterotopic ossification following acetabular surgery. Following total hip arthroplasty, other non-steroidal anti-inflammatory drugs, including naproxen and diclofenac, are equally as effective as indometacin and can be considered as alternative first-line treatments. Celecoxib is also of equal efficacy to indometacin and is associated with significantly fewer gastrointestinal side effects. However, serious concerns were raised over the safety of selective cyclooxygenase-2 inhibitors for the cardiovascular system and these should be used cautiously.

Interspinous distraction in lumbar spinal stenosis: a neurophysiological perspective.

Study Design. Prospective neurophysiological study. Objective. To identify and quantify the neurophysiological effects of interspinous distraction during spine surgery for lumbar spinal stenosis (LSS). Summary of Background Data. Interspinous devices have been introduced as an alternative treatment of LSS in selected patients aiming at obtaining indirect decompression. Nevertheless, there is no data on the immediate neurophysiological effect of distraction. Methods. Thirty patients with LSS undergoing decompression (14 at single level, 16 at multiple levels) were enrolled, resulting in a total of 48 levels to be analyzed. Before decompression, calibrated incremental distraction simulating interspinous device implantation of 8, 10, 12, 14, and 16 mm was performed. Intraoperative motor evoked potentials were acquired before any distraction, during distraction at each incremental value and after bilateral decompression. We evaluated relative changes of motor evoked potentials normalized to hand muscles and related them to the number of affected levels, LSS radiological severity based on the A to D grading, lordosis, and disc height. Results. For single-level disease, 8-mm distraction and open decompression yielded similar improvement in motor evoked potentials not only in levels with morphological grades A or B, but also in levels with morphological grades C or D (i.e., severe or extreme stenosis) (P = 0.32). In contrast, distraction superior to 8 mm was less effective (P ⩽ 0.05). In multiple-level stenosis, decompression was significantly more effective than any degree of distraction (P < 0.001). No correlation of those results to disc height or lordosis was observed. Using &khgr;2 trend test to analyze the effect of distraction, a linear trend favoring moderate over severe stenotic morphology was observed (P = 0.0349). Conclusion. Interspinous distraction of 8 mm is sufficient to replicate electrophysiological improvements obtained during full decompression even in severe single-level stenosis but not in multilevel disease. Interspinous distraction has therefore an immediately measurable neurophysiological effect. Level of Evidence: 4

Secular changes of spinal canal dimensions in Western Switzerland: a narrowing epidemic?

Study Design. Computed tomography–based anatomical study. Objective. To study the secular changes in lumbar spinal canal dimensions. Summary of Background Data. Development of symptomatic lumbar spinal stenosis, among other factors, is related to the dimensions of the bony canal. The canal reaches its adult size early on in life. Several factors, including protein intake, may influence its final dimensions. As with increases in human stature from improvements of socioeconomic conditions, we hypothesized that adult bony canal size has also grown larger in recent generations. Methods. This study analyzes computed tomographic reconstructions from 184 subjects performed for either trauma (n = 81) or abdominal pathologies (n = 103) and born either between 1940 and 1949 (n = 88) or 1970 and 1979 (n = 96). The cross-sectional area of the bony canal was digitally measured at the level of the pedicle (i.e., at a level not influenced by degenerative changes) for each lumbar vertebra. Intra- and interobserver reliability was assessed. Results. Intra- and interobserver measurement reliability were excellent (interclass correlation coefficient = 0.87) and good (interclass correlation coefficient = 0.61), respectively. Contrary to our hypothesis, the 1940–1949 generation patient group exhibited larger lumbar canals at all levels as compared with the 1970–1979 group. Statistically this difference was highly significant (P < 0.001) and particularly pronounced in the trauma subgroup. Conclusion. Given that human stature evolution has stabilized and adult height is established during the first 2 years of long bone growth, it is possible that antenatal factors are responsible for this surprising finding. Maternal smoking and age may be possible explanations. This finding may have significant implications. An increasing number of patients may emerge with lumbar spinal stenosis as degenerative changes develop, putting a strain on health resources. Further studies in different population groups and countries will be important to further confirm this trend. Level of Evidence: 3

Neurophysiological changes during shortening osteotomies of the spine

BACKGROUND CONTEXTnKyphotic deformities with sagittal imbalance of the spine can be treated with spinal osteotomies. Those procedures are known to have a high incidence of neurological complications, in particular at the thoracic level. Motor evoked potentials (MEPs) have been widely used in helping to avoid major neurological deficits postoperatively. Previous reports have shown that a significant proportion of such cases present with important transcranial MEP (Tc-MEP) changes during surgery with some of them being predictive of postoperative deficits.nnnPURPOSEnOur aim was to study Tc-MEP changes in a consecutive series of patients and correlate them with clinical parameters and radiological changes.nnnSTUDY DESIGN/SETTINGnRetrospective case notes study from a prospective patient register.nnnPATIENT SAMPLEnEighteen patients undergoing posterior shortening osteotomies (nine at thoracic and nine at lumbar levels) for kyphosis of congenital, degenerative, inflammatory, or post-traumatic origin were included.nnnOUTCOME MEASURESnLoss of at least 80% of Tc-MEP signal expressed as the area under the curve percentual change, of at least one muscle.nnnMETHODSnWe studied the relation between outcome measure (80% Tc-MEP loss in at least one muscle group) and amount of posterior vertebral body shortening as well as angular correction measured on computed tomography scans, occurrence of postoperative deficits, intraoperative blood pressure at the time of the osteotomy, and hemoglobin (Hb) change.nnnRESULTSnAll patients showed significant Tc-MEP changes. In particular, greater than 80% MEP loss in at least one muscle group was observed in five of nine patients in the thoracic group and four of nine patients in the lumbar group. No surgical maneuver was undertaken as a result of this loss in an effort to improve motor responses other than verifying the stability of the construct and the extent of the decompression. Four patients developed postoperative deficits of radicular origin, three of them recovering fully at 3 months. No relation was found between intraoperative blood pressure, Hb changes, and Tc-MEP changes. Severity of Tc-MEP loss did not correlate with postoperative deficits. Shortening of more than 10 mm was linked to more severe Tc-MEP changes in the thoracic group.nnnCONCLUSIONSnTranscranial MEP changes during spinal shortening procedures are common and do not appear to predict severe postoperative deficits. Total loss of Tc-MEP (not witnessed in our series) might require a more drastic approach with possible reversal of the correction and wake-up test.

Do intra-operative neurophysiological changes predict functional outcome following decompressive surgery for lumbar spinal stenosis? A prospective study

BackgroundnTo analyse the relation between immediate intraoperative neurophysiological changes during decompression and clinical outcome in a series of patients with lumbar spinal stenosis (LSS) undergoing surgery.nnnMethodsnTwenty-four patients with neurogenic intermittent claudication (NIC) due to LSS undergoing decompressive surgery were prospectively studied. Intra operative trans-cranial motor evoked potentials (tcMEPs) were recorded before and immediately after surgical decompression. Lower limb normalised tcMEP improvement was used as primary neurophysiological outcome. Clinical outcome was assessed using the Zurich Claudication Questionnaire (ZCQ) self-assessment score, before surgery (baseline) and at an average of 8 and 29 months post-operatively.nnnResultsnWe found a moderate positive correlation between tcMEP changes and ZCQ at early follow-up (R=0.36). At late follow-up no correlation was found between intra-operative tcMEP and ZCQ changes. Dichotomizing the data showed a statistically significant relationship between tcMEP improvement and better functional outcome at early follow-up (P=0.013) but not at later follow-up (P=1).nnnConclusionsnOur findings suggest that intra-operative neurophysiological improvement during decompressive surgery may predict a better clinical outcome at early follow-up although this is not applicable to late follow-up possibly due to the observed erosion of functional improvement with time.

Dimensional changes of cervical and lumbar bony spinal canals in one generation in Western Switzerland: a computed tomography study

PurposeWe aimed to study generational changes in the dimensions of cervical and lumbar bony spinal canals in Western Switzerland.MethodsA total of 254 patients were retrospectively included, 144 of whom were born during 1940–1949 and 110 during 1970–1979. Cervical spine CTs were performed as part of the spinal clearance procedure following trauma (nxa0=xa0135) or while investigating neurological symptoms (CT angiography, nxa0=xa0119). Three independent observers digitally measured the cross-sectional area (CSA) at pedicle levels from C0 to C7 and the anteroposterior diameter (APD) at C3, C5, and C7. In addition, lumbar spine CSAs and APDs were measured on whole body trauma or abdominal CTs, which were also available for 134 patients.ResultsMean CSAs at pedicle levels were numerically smaller in the younger patient group in both cervical and lumbar spine, with the difference reaching statistical significance at all lumbar levels (pxa0≤xa00.024) except L5. Cervical APDs showed no difference between groups. Subgroup analysis revealed that younger CT angiography patients had a significantly smaller CSA at C1 (pxa0=xa00.018) and a similar trend at C4 (pxa0=xa00.053). There was moderate positive correlation between cervical and lumbar CSAs, taking C4 and L3 as reference (rxa0=xa00.509, pxa0<xa00.01).ConclusionsYounger generation patients have smaller bony spinal canals also in the cervical spine even though this difference is less marked than at the lumbar level. There is, nevertheless, moderate positive correlation between these two anatomical regions. Perinatal factors that adversely influence spinal growth, such as increased maternal age and smoking, could explain these generational changes, given that body height has increased during the same time period. The lesser difference observed in the cervical spine could be due to later closure of the neurocentral synchondrosis at this level.

P02-296 Modelling the effect of minor orthopaedic day surgery on patient mood at the early post-operative period: A prospective population-based study

Objective The effect of minor orthopaedic day surgery (MiODS) on patients mood. Methods A prospective population-based cohort study of 148 consecutive patients with age above 18 and less than 65, an American Society of Anaesthesiology (ASA) score of 1, and the requirement of General Anaesthesia (GA) were included. The Medical Outcomes Study-Short Form 36 (SF-36), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were used pre- and postoperatively. Results The mean physical component score of SF-36 before surgery was 45.3 (SD = ±10.1) and 8 weeks following surgery was 44.9 (SD = ±11.04) [n = 148, p = 0.51, 95%CI = (-1.03 -1.52)]. For the measurement of the changes in mood using BDI, BAI and SF-36, latent construct modelling was employed to increase validity. The covariance between mood pre- and post-operatively (cov = 69.44) corresponded to a correlation coefficient, r = 0.88 indicating that patients suffering a greater number of mood symptoms before surgery continue to have a greater number of symptoms following surgery. When the latent mood constructs were permitted to have different means the model fitted well with χ2 (df = 1) = 0.86 for which p = 0.77, thus the null hypothesis that MiODS has no effect on patient mood was rejected. Conclusions MiODS affects patient mood which deteriorates at 8 weeks post-operatively regardless of the pre-operative patient mood state. More importantly patients suffering a greater number of mood symptoms before MiODS continue to have a greater number of symptoms following surgery.