Personality disorders and response to outpatient treatment of chronic pain

As part of a comprehensive interdisciplinary evaluation conducted prior to participation in an outpatient chronic pain treatment program, the psychological status of 101 persons was assessed. The majority of participants was found to have a form of personality disorder, determined by conservative cutoff scores applied to their Millon Clinical Multiaxial Inventory (MCMI) profiles. DSM-III-R Cluster C disorders (i.e., Avoidant, Dependent, Obsessive-Compulsive, and Passive-Aggressive) were overrepresented in this sample. Subsequent analyses revealed that personality disorders were related to higher levels of self-reported distress and pain at both the beginning and the end of outpatient treatment. Differential responses to treatment were observed on self-report measures; however, few relations were found between personality disorder and physical therapist ratings of impairment and improvement. Implications for the assessment of personality disorders in outpatient pain treatment programs are discussed and appropriate intervention strategies are considered.

Pharmacologic actions of the second generation leukotriene B4 receptor antagonist LY29311: in vivo pulmonary studies

We examined the in vivo actions of LY293111 sodium (2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]pro poxy]phenoxy] benzoic acid sodium salt). Guinea pigs were used to evaluate the effect of this agent on (1) acute airway obstruction produced by intravenous leukotriene B4, (2) pulmonary granulocyte infiltration and delayed onset airway obstruction resulting from a 4-h leukotriene B4 inhalation and (3) lung inflammation after aerosol challenge with the divalent cationic ionophore A23187 (6S-[6alpha(2S*,3S*),8beta(R*),9beta,11alpha]-5- (methylamino)-2-[[3,9,11-trimethyl-8-[1-methyl-2-oxo-2-(1H-pyrrol-2-yl)e thyl]-1,7-dioxaspiro[5.5]undec-2-yl]methyl]-4-benzoxazole carboxylic acid). Airway obstruction was quantitated using pulmonary gas trapping measurements and lung inflammation was evaluated by bronchoalveolar lavage (BAL) and histology. LY293111 sodium produced a dose-related inhibition of acute leukotriene B4-induced airway obstruction when administered i.v. (ED50=14 microg/kg) or p.o. (ED50=0.4 mg/kg). In contrast, LY293111 sodium did not inhibit the pulmonary gas trapping caused by aerosols of histamine, leukotriene D4, or the thromboxane mimetic U46619 (15 [(S)-hydroxy11a,9a-(epoxymethano)prosta-5Z,13E-dienoic acid]). Oral LY293111 sodium inhibited leukotriene B4-induced bronchoalveolar lavage granulocyte infiltration and delayed onset airway obstruction at doses as low as 0.3 mg/kg. In A23187-challenged animals, pulmonary inflammation was markedly inhibited at 1 h, but not 2 h and 4 h post-exposure. We conclude that LY293 11 sodium is a selective leukotriene B4 receptor antagonist with potent pulmonary anti-inflammatory activity.

Cognitive orientation in rehabilitation and neuropsychological outcome after traumatic brain injury

This study evaluated the ability of the Orientation Log (O-Log) to predict cognitive outcome at rehabilitation discharge, as well as future neuropsychological outcome. The hypothesis was that patients who demonstrated better orientation upon admission would achieve superior functional cognitive outcome at discharge and on subsequent neuropsychological assessment. Sixty individuals receiving inpatient rehabilitation following a new-onset TBI participated. Orientation data was collected using the O-Log during morning bedside rounds. Outcome data was collected at 6 and 12 months post-injury. Significant correlations were found between the O-log and measures of memory, executive functioning, basic verbal skills, and estimated intellectual ability. When compared to the other predictor variables, step-wise multiple regression analyses revealed that the minimum O-Log score was the primary significant predictor of performance on six neuropsychological and functional outcome measures. Results of this study suggest that evaluating orientation with the O-Log during acute rehabilitation may reflect level of injury severity and aid in predicting cognitive outcome.

Extensile approach to the anterolateral surface of the humerus and the radial nerve

A proposed approach to the anterolateral surface of the humeral shaft that would allow for exploration of the radial nerve was studied in 30 cadaver arms. The incision starts proximally along the posterior border of the deltoid muscle and extends anteriorly and distally over the lateral border of the biceps muscle. A deep dissection is made in the internervous plane between the deltoid and the triceps muscles proximally and between the longitudinally split fibers of the brachialis muscle distally. The approach provides access to the anterolateral surface of the humerus up to the level of the axillary nerve and the posterior circumflex humeral vessels. The insertion of the deltoid muscle into the anterior border of the humerus is preserved and the radial nerve is protected by the triceps muscle proximally and by the retracted lateral portion of the brachialis muscle distally. The entire course of the radial nerve in the arm can be exposed. Proximally, the radial nerve can be exposed by elevating the lateral head of the triceps muscle from the humerus. Distally, the radial nerve can be exposed between the brachioradialis and the brachialis muscles. A plate can be applied on the anterolateral surface of the humerus without having to elevate the firmly attached anterior deltoid insertion.

Pharmacologic actions of the second-generation leukotriene B4 receptor antagonist LY293111: in vitro studies

The in vitro actions were investigated of LY293111, a potent and selective leukotriene B4 (LTB4) receptor antagonist, on human neutrophils, human blood fractions, guinea pig lung membranes, and guinea pig parenchymal and tracheal strips. The IC50 for inhibiting [3H]LTB4 binding to human neutrophils was 17.6 +/- 4.8 nM. LY293111 inhibited LTB4-induced human neutrophil aggregation (IC50 = 32 +/- 5 nM), luminol-dependent chemiluminescence (IC50 = 20 +/- 2 nM), chemotaxis (IC50 = 6.3 +/- 1.7 nM), and superoxide production by adherent cells (IC50 = 0.5 nM). Corresponding responses induced by N-formyl-L-methionyl-L-leucyl-L-phenylalanine were inhibited by 100-fold higher concentrations of LY293111. LTB4 binding to guinea pig tissues and subsequent activation were also inhibited. The Ki for inhibition of [3H]LTB4 binding to lung membranes was 7.1 +/- 0.8 nM; IC50 for preventing binding of [3H]LTB4 to spleen membranes was 65 nM. The compound inhibited LTB4-induced contraction of guinea pig lung parenchyma. At 10 nM, LY293111 caused a parallel rightward shift of the LTB4 concentration-response curve. At higher concentrations, plots were shifted in a nonparallel manner, and maximum responses were depressed. LY293111 did not prevent antigen-stimulated contraction of sensitized trachea strips. At micromolar concentrations, LY293111 inhibited production of LTB4 and thromboxane B2 by plasma-depleted human blood stimulated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine and thrombin. In addition, at these higher concentrations, formation of LTB4 by A23187-activated whole blood and conversion of arachidonic acid to LTB4 by a human neutrophil cytosolic fraction were inhibited. In summary, LY293111 is a second-generation LTB4 receptor antagonist with much improved potency in a variety of functional assay systems.

Visual reproduction subtest of the Wechsler Memory Scale-Revised: analysis of construct validity

This study assessed the construct validity of Visual Reproduction (VR) Cards A (Flags) and B (Boxes) from the original Wechsler Memory Scale (WMS) compared to Flags and Boxes from the revised edition of the WMS (WMS-R). Independent raters scored Flags and Boxes using both the original and revised scoring criteria and correlations were obtained with age, education, IQ, and four separate criterion memory measures. Results show that for Flags, there is a tendency for the revised scoring criteria to produce improved construct validity. For Boxes, however, there was a trend in the opposite direction, with the revised scoring criteria demonstrating worse construct validity. Factor analysis suggests that Flags are a more distinct measure of visual memory, whereas Boxes are more complex and significantly associated with conceptual reasoning abilities. Using the revised scoring criteria, Boxes were found to be more strongly related to IQ than Flags. This difference was not found using the original scoring criteria.

Effective serial measurement of cognitive orientation in rehabilitation: the Orientation Log

OBJECTIVE

To introduce a brief quantitative measure of cognitive orientation (to place, time, and situation) developed for daily use at bedside with rehabilitation inpatients. The Orientation Log (O-Log) is a 10-item scale that allows for partial credit based on responsiveness to logical, multiple-choice, or phonemic cueing. It is formatted for rapid visual analysis of orientation trends that can be used to evaluate pharmacologic and cognitive-behavioral interventions.

DESIGN

Descriptive study of the O-Log's reliability (interrater and internal consistency).

SETTING

Inpatient rehabilitation center affiliated with a large university medical school.

PATIENTS

Fifteen neurorehabilitation inpatients.

RESULTS

For individual items, Spearman rho interrater reliability coefficients ranged from .851 to 1.00. The interrater reliability of the total score was .993. O-Log internal consistency (coefficient alpha) was .922.

CONCLUSIONS

The O-Log is a reliable and easily administered scale that promises to be a useful tool in monitoring cognitive recovery during rehabilitation.

Radiology of the sacroiliac joint

STUDY DESIGN

Radiology of the sacroiliac joint was investigated by obtaining different and multiple radiographs of cadaveric pelves marked with solder metal wire and radiopaque paint.

OBJECTIVES

To demonstrate the orientation of the sacroiliac joint on various, radiographic views.

SUMMARY OF BACKGROUND DATA

Interpretation of the sacroiliac joint projection on plain radiography is difficult. It requires an understanding and appreciation of its components and their orientation. Emphasizing the definition of the orientation of the plane of the joint on the different projection views of the sacroiliac joints can aid the orthopaedic surgeon in obtaining the proper radiographs and in the proper interpretation of the different radiographic views.

METHODS

Nineteen sacroiliac joints from 10 cadaveric pelves, 5 male and 5 females were studied. Each joint was found to be composed of three portions: anterosuperior, middle, and posteroinferior portions, each lying in a different plane. Each sacroiliac joint was marked with solder wires and radiopaque paint to define the orientation of each of the three portions of the joint on radiographs. The following radiographic projection views were taken for each joint anteroposterior, lateral, inlet, craniocaudal axial, outlet, lithotomy and oblique views. For the oblique views, the angulation of the x-ray tube needed to view each portion of the joint tangentially was recorded.

RESULTS

There was a wide variation in the orientation of the planes of the joint portions between the right and the left sides as well as between different pelves. Although the twisting of the plane of the whole joint produced by the successive examination of the portions could be either internal or external, it was the same bilaterally in a given specimen. The outlet and lithotomy views provided the best tangential representation of the two sacroiliac joints on one film.

CONCLUSION

The sacroiliac joint is composed of three portions oriented in different planes. To study the sacroiliac joints, it seems desirable to obtain an anteroposterior view of the pelvis with the patient in a lithotomy position; then, if needed, each joint can be radiographed separately by using oblique views. It is important to not that the plane of the articular portion of the joint can be directed from anterolateral to posteromedial, and therefore, the oblique views should be obtained accordingly.

Femoral neck fracture following intertrochanteric fracture

Four patients with femoral neck fracture following healed intertrochanteric fracture were evaluated retrospectively. This situation is a rare occurrence with a current literature review documenting only 15 cases. Patient charts and radiographs were retrospectively reviewed to evaluate the period from initial injury to definitive treatment for the femoral neck fracture. Emphasis was placed on associated risk factors and operative techniques. In case 1, the femoral neck fracture appeared to be clearly a traumatic fracture as it occurred 11 years after the intertrochanteric fracture. In cases 2, 3, and 4, multiple factors were believed to play a role in the generation of the femoral neck fractures, which occurred within 6 months of the original fracture. The etiology of such fractures remains speculative. All four patients were elderly, women with substantial medical comorbidities. Osteoporosis may be the most important single contributing factor to these fractures. Because management of this patient subgroup is notably more complex, surgeons need to be aware of the difficulties and prepared to deal with them.

Neurochemical mechanisms in brain injury and treatment: a review

This article reviews cellular energy transformation processes and neurochemical events that take place at the time of brain injury and shortly thereafter emphasizing hypoxia-ischemia, cerebrovascular accident, and traumatic brain injury. New interpretations of established concepts, such as diffuse axonal injury, are discussed; specific events, such as free radical production, excess production of excitatory amino acids, and disruption of calcium homeostasis, are reviewed. Neurochemically-based interventions are also presented: calcium channel blockers, excitatory amino acid antagonists, free radical scavengers, and hypothermia treatment. Concluding remarks focus on the role of clinical neuropsychologists in validation of treatment interventions.

Extensile medial approach to the femur

A proposed extensile medial approach to the medial surface of the shaft of the femur was studied on 30 cadaver thighs. The incision is made along a line extending from the mid inguinal point to a point one-third the distance from the adductor tubercle to the medial side of the patella. After mobilizing the sartorius muscle posteromedially, the medial femur is exposed by a three-step technique. Step I involves bluntly defining the internervous plane distally between the vastus medialis muscle and the adductor magnus tendon until limited proximally by the distal end of the vastoadductor membrane at an average of 9 cm from the adductor tubercle. In step II blunt dissection between the vastus medialis and the adductor longus muscles is carried from proximal to distal until limited by the proximal end of the vastoadductor membrane. Now the well-defined vastoadductor membrane area ("danger zone") measuring 6 cm in length on average is safely dealt with (step III) and the medial femur is exposed. Distal extension can be made to expose the knee joint. The approach can be extended proximally to the lesser trochanter between the vastus medialis and both the adductor brevis and pectineus muscles. Anatomic measurements in relation to the adductor tubercle and cross-sections of the thigh were made to better describe anatomic constants and variables in this rather unfamiliar medial thigh area.

Anatomic considerations for the anterior exposure of the proximal portion of the radius

The rate of posterior interosseous nerve injury is still of major concern during surgical exposure of the proximal portion of the radius. The objective of this study was to find the best way to protect the important neurovascular structures during anterior exposure of the proximal radius and to define the safest anatomic orientation for plate and screw placement during open reduction and internal fixation of the proximal radius. In 30 cadaveric upper limbs, the proximal portion of the radius was exposed through a modified anterior Henry approach. The important anatomic structures were localized and demonstrated on radiographs. Plates and screws were applied anterolaterally (in five specimens) and laterally (in another five specimens), and the locations of the safe and danger zones were noted. Lateral placement of the plate is preferred over the more commonly used anterolateral plating, because it carries less risk of injuring the posterior interosseous nerve during screw application and it does not impinge on the biceps tendon and block pronation.

Talar neck fractures: anatomic considerations for posterior screw application

The bony window available for posterior screw placement in the talus and the morphology of the talar neck were studied in 50 dry tali. In addition, 12 cadaver specimens were used to study the posterolateral approach. The bony window was bounded medially by the lateral tubercle of the posterior process of the talus, laterally by the fibular facet, superiorly by the trochlear articular surface, and inferiorly by the posterior calcaneal facet. The average vertical thickness at 2-mm increments was recorded across the talar neck to define the bony mass available for screw insertion. The smallest thickness of the talar neck was at a point 2 mm medial to the lateral border. The thickness progressively increased in a medial direction. The superior talar neck surface was found to have an average width of 18.4 +/- 1.6 mm. The angle formed between the superior and lateral surfaces of the talar neck averaged 29.3 degrees, which would account for the better delineation of the lateral border of the neck under fluoroscopy of the talus with the foot in pronation. The diameter of the screw in relation to the window height should be considered.

Recombinant human secretory phospholipase A2 released thromboxane from guinea pig bronchoalveolar lavage cells: in vitro and ex vivo evaluation of a novel secretory phospholipase A2 inhibitor

The primary objective of this study was to develop a functional assay that could provide rapid and reliable information on some pharmacologic characteristics of a novel inhibitor of human secretory phospholipase A2 (sPLA2). Guinea pig bronchoalveolar lavage (BAL) fluid, containing predominantly macrophages, eosinophils and epithelial cells, released thromboxane A2, as measured by thromboxane B2, in a concentration-dependent manner on exposure to recombinant human sPLA2 (rh-sPLA2). Similarly, n-formyl-L-methionyl-L-leucyl-L-phenylalanine (n-F-Met-Leu-Phe) or arachidonic acid also released this lipid mediator. Indomethacin, a cyclooxygenase inhibitor, blocked synthesis of thromboxane in response to these agents. p-Bromophenacylbromide-inactivated rh-sPLA2 was substantially less effective than the untreated enzyme in causing release of thromboxane. LY311727 is a potent indole-derived inhibitor of the isolated enzyme (IC50 = 23 nM). Incubation of this agent with BAL cells, just before addition of rh-sPLA2, reduced release of thromboxane with an IC50 = 1.8 x 10(-6) M. Specificity for sPLA2 was demonstrated in that LY311727, unlike indomethacin, did not reduce synthesis and subsequent release of thromboxane A2 in response to arachidonic acid. Using this technique as a basis, we determined whether LY311727 could sufficiently accumulate in lung after i.v. administration to inhibit rh-sPLA2-induced thromboxane A2 release from BAL cells. The compound, given i.v. to guinea pigs 5 min before collecting BAL fluid, produced a dose-dependent inhibition of rh-sPLA2 with an ED50 = 50 mg/kg. Thus, new in vitro and ex vivo assays were developed that permit functional evaluation of novel sPLA2 inhibitors. These techniques should serve as secondary assays for evaluation of human sPLA2 inhibitory activity from a chemical series and in addition provide initial data related to metabolic stability and distribution to the lung.

Anatomic and X-ray film studies of the distal articular surface of the radius

Knowledge of the surgical and topographic anatomy of the distal articular surface of the radius is valuable during diagnostic and operative procedures involving the distal radius. The aim of this study is to assist the surgeon in determining the location, displacement, and angulation of acute or healed distal radius articular fractures. Measurements were taken of the distal articular surface of 50 dry radii. Also, the margins and surfaces of the distal articular surface of 12 adult cadaver radii were marked by solder and radiopaque dye, respectively. X-ray films were then taken to define the margins and bony landmarks. The lunate facet surface area (53%) was found to be slightly larger than the scaphoid facet surface area (47%). Both the palmar tilt and the radial inclination were demonstrated on the marked x-ray films. Using the 30 degrees cephalad angled anteroposterior projection of the distal radius can help assess the dorsomedial fragment of the lunate fossa in a die-punch fracture.

Anatomic considerations for posterior iliac bone harvesting

STUDY DESIGN

This study analyzed bony features of the posterior ilium and relevant vital structures using cadavers and dry ilium specimens.

OBJECTIVES

To determine quantitatively the safely zone of the posterior ilium and relevant vital structures with regard to bone graft harvesting.

SUMMARY OF BACKGROUND DATA

The most frequently used site for bone graft harvesting is the posterior ilium. However, complications related to posterior iliac bone harvesting, such as donor site pain, neurovascular injury, instability of the sacroiliac joint, and herniation of abdominal contents, are still major concerns. Very little research with regard to the quantitative study of the posterior ilium has been reported.

METHODS

Six cadavers (four male, two female) were used for the first part of this study. The posterior superior iliac spine was determined as a reference landmark. The distances from the posterior superior iliac spine to the superior cluneal nerves, the gluteal line, and the superior gluteal vessels were measured. The second part of the study involved 30 adult, dry iliac bony specimens. The posterior iliac region (extra-articular portion) was divided into three zones, and the corresponding dimensions of these zones were measured.

RESULTS

The average distances from the posterior superior iliac spine to the superior cluneal nerves, gluteal line, and superior gluteal vessels were 68.8, 26.6, and 62.4 mm, respectively. The average width, height, and maximum thickness for Zone 1 were 34, 27.8, and 17.1 mm, respectively; the measurements for Zone 2 were 16.5, 31.8, and 14.2 mm, respectively. The average height for Zone 3 was 20.4 mm, and the average maximum thickness was 16.8mm.

CONCLUSION

The ideal area of the posterior ilium for bone graft harvesting was found in Zone 1. Zones 2 or 3 may be considered it a greater quantity of cancellous bone graft is required; however, the risk of injury to the sacroiliac joint and superior gluteal vessels in these zones is increased.

Anatomic consideration of C2 pedicle screw placement

STUDY DESIGN

This anatomic study tested placement of C2 pedicle screws using cadaver specimens.

OBJECTIVES

To further assess the safety of transpedicular screw placement in the axis by comparing two surgical techniques.

SUMMARY OF BACKGROUND DATA

Transpedicular screw fixation of traumatic spondylolisthesis of the axis has been described in the literature. Recently, anatomic studies and clinical applications of transpedicular screw fixation for traumatic lesions of middle and lower cervical spine have been described. No previous study assessing the safety of C2 pedicle screw placement is available.

METHODS

Sixteen embalmed cadaveric specimens were used for this study. In the first eight specimens (Method A), the point of entry for screw placement was chosen to be about 5 mm inferior to the superior border of C2 lamina and 7 mm lateral to the lateral border of the spinal canal. The screw direction was chosen to be about 30 degrees medial to the sagittal plane and 20 degrees cephalad to the transverse plane. A 3.5-mm cortical screw of appropriate length, determined with depth gauge, was placed bilaterally into the C2 pedicle. In the next eight specimens (Method B), the direction of the drill bit was guided directly by the medial and superior aspect of the individual C2 pedicle. Gross dissection was done to view violation of dura, nerve roots, vertebral artery, and penetration of medial, lateral, superior, and inferior cortex of the C2 pedicle. Radiographs and computed tomography scans were obtained to evaluate screw placement in the C2 pedicle.

RESULTS

In Method A, four screws had lateral violations into the vertebral artery. In Method B, only two cases of minimal penetration of pedicle cortex were found. No medial, superior, or inferior violation of the pedicle cortex was found in the present study.

CONCLUSIONS

The present anatomic study suggests that transpedicular screw fixation may be performed safely in the C2 pedicle by using the second technique. Using the first technique is not safe.

Anatomical considerations of irreducible medial subtalar dislocation

Irreducible medial subtalar dislocation has been associated with the talar head "buttonholing" through the extensor digitorum brevis (EDB) muscle, entrapment of the talar head in the extensor retinaculum, talonavicular impaction, interpositioning of the EDB muscle between the talus and navicular, and buttonholing of the talar head through the talonavicular ligament and joint capsule. Cadaver analysis of the medial subtalar dislocation in this study supported entrapment of the talar head in the extensor retinaculum and talonavicular impaction as well as impingement of the deep peroneal nerve and associated dorsalis pedis arterial branches between the talus and navicular as causes of irreducible subtalar dislocation. In this study, the talar head was not noted to buttonhole through or entrap the EDB muscle. This is the first report of the deep peroneal nerve implicated as a possible cause of irreducible medial subtalar dislocation.

Aerosolized LTB4 produces delayed onset increases in pulmonary gas trapping

Airway obstruction, as measured by increases in postmortem pulmonary gas trapping, and lung inflammatory changes were examined in guinea pigs exposed for up to 4 h to aerosols of leukotriene B4 (LTB4) or its non-chemotactic isomer, 6-trans-12-epi-LTB4. Airway obstruction and cytological responses in isomer-exposed animals were similar to those of unexposed control animals. LTB4-exposed animals had minimal inflammatory changes at 0.5 h but became dyspneic by 2 h and had increased airway obstruction, bronchoalveolar lavage neutrophils and eosinophils, and pulmonary tissue granulocyte scores. The LTB4-induced effects at 4 h were similar to those 2 h, except for further increase in BAL neutrophils and eosinophils. LTB4-induced airway obstructive and inflammatory changes were prevented by pretreatment with the LTB4 receptor antagonist SC-41930, but were unaffected by indomethacin. Thus, prolonged LTB4 inhalation can produce delayed onset airway obstruction that is stereospecific, cyclooxygenase-independent, and temporally associated with the influx of granulocytes into lung airways.

Synthetic and structure/activity studies on acid-substituted 2-arylphenols: discovery of 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5- hydroxyphenoxy]-propoxy]phenoxy]benzoic acid, a high-affinity leukotriene B4 receptor antagonist

Structural derivatives of LY255283 have been studied as receptor antagonists of leukotriene B4. Substitution of the 2-hydroxyacetophenone subunit of 1 (LY255283) with a 2-arylphenol group provided entry into several new series that feature various mono- and diacidic core functionality. These new analogues, the subject of a broad structure-activity investigation, displayed significantly increased in vitro and in vivo activity as receptor antagonists of LTB4. A series of diaryl ether carboxylic acids demonstrated especially interesting activity and led to the discovery of compound 43b, 2-[2-propyl-3-[3-[2-ethyl-4-(4- fluorophenyl)-5-hydroxyphenoxy]-propoxy]phenoxy]benzoic acid (LY293111), a 2-arylphenol-substituted diaryl ether carboxylic acid which displayed potent binding to human neutrophils (IC50 = 17 +/- 4.6 nM) and guinea pig lung membranes (IC50 = 6.6 +/- 0.71 nM), inhibition of LTB4-induced expression of the CD11b/CD18 receptor on human neutrophils (IC50 = 3.3 +/- 0.81 nM), and inhibition of LTB4-induced contraction of guinea pig lung parenchyma (pKB = 8.7 +/- 0.16). In vivo, 43b demonstrated potent activity in inhibiting LTB4-induced airway obstruction in the guinea pig when dosed by the oral (ED50 = 0.40 mg/kg) or intravenous (ED50 = 0.014 mg/kg) routes. A specific LTB4 receptor antagonist, 43b had little effect on inhibiting contractions of guinea pig lung parenchyma induced by leukotriene D4 (LTD4), histamine, carbachol, or U46619. Compound 43b has been chosen as a clinical candidate and is currently in phase I studies for a variety of inflammatory diseases.

Difficulty in removal of the distal locking device of the Brooker-Wills tibial nail

Complications in removal of the Brooker-Wills tibial nail were encountered in eight patients, and breakage of the distal fins occurred in four of these patients. Although none of the patients experienced residual effects related to removal of the tibial nail, the procedure is associated with potential risks such as infection or nonunion. Three methods of nail removal are described.

Anatomic relationships of the cervicothoracic junction

STUDY DESIGN

This study analyzed the anatomic relationships between bony structures and soft tissues of the cervicothoracic junction.

OBJECTIVES

To provide composite reference data for intrasegmental and intersegmental gradients of anatomic variation within the cervical-thoracic junction.

SUMMARY OF BACKGROUND DATA

Because the risk of soft tissue damage during posterior spinal stabilization, an understanding of bony and soft tissue changes in the cervicothoracic junction is necessary.

METHODS

Three-hundred-twenty-four cross-sectional spinal segments from nine spines were analyzed to characterize cervicothoracic junctional anatomy.

RESULTS

There were predictable cranial-to-caudal alterations in both bone and soft tissue anatomy of the cervicothoracic junction. Neural and vascular structures directly anterior to the lateral mass or transverse process and lateral to the pedicle tend to decrease in frequency, whereas measured parameters of the vertebrae increase in size from C5-T3, except for pedicle dimensions that tend to increase at the C7-T1 junction.

CONCLUSION

The anatomic changes that occur within the cervicothoracic junction are consistent and predictable, and their recognition should lead to a better appreciation of their clinical implications.

Arthroscopy of the subtalar joint: establishing a medial portal

One of the recently introduced procedures for studying the posterior subtalar joint is subtalar arthroscopy. There is no reference in the literature to the possibility of a medial portal that might be used either for arthroscopic insertion, probing, or instrumental manipulation. The two portals mentioned in the literature are the anterolateral and the posterolateral portals. For evaluating the possibility of establishing a medial portal, six embalmed adult cadaver feet were used to study the anatomical relations to the proposed medial portal. The subtalar joints of another six fresh adult cadaver feet were then arthroscoped, after distraction of the joint, using the anterolateral, posterolateral, and medial portals. Findings indicated that the medial portal gives good visualization of the posterior subtalar joint. Clinical application has not yet been assessed.

Vulnerability of the posterior interosseous nerve during proximal radius exposures

This study describes the anatomy of the posterior interosseous nerve and proposes how to protect it during the different approaches to the proximal radius. Based on the findings presented here, the choice of the approach and the pitfalls that might cause posterior interosseous nerve injury were defined. Three surgical approaches were used on 30 cadaveric upper limbs: modified Henry's anterior approach, Thompson's posterior approach, and a modified Gordon-Boyd's approach. Important anatomic structures were localized, marked, and shown on radiographs. Plates and screws were applied through the different approaches to determine the relationship of the hardware to the posterior interosseous nerve. Measurements were taken between the humeroradial joint, as a reference point, and different important anatomic structures. It was concluded that the anterior approach to the proximal radius is relatively safe and offers the possibility of proximal and distal extension. Caution should be taken while applying screws, however, to avoid posterior interosseous nerve injury. The radius is superficial posteriorly, and many surgeons favor Thompson's approach for exposure of the proximal radius; nonetheless, it carries the risk of posterior interosseous nerve injury with exposure of the most proximal portion of the radius. The modified Gordon-Boyd's approach offers the advantage of exposing both the radius and the ulna, but necessitates excessive muscle stripping.

Morphometric evaluation of the first sacral vertebra and the projection of its pedicle on the posterior aspect of the sacrum

STUDY DESIGN

This study directly measured the dimensions of the first sacral vertebra based on dry bony specimens.

OBJECTIVES

To measure the dimensions of the S1 pedicle, vertebral body, and spinal canal, and determine the projections of the S1 pedicle on the posterior aspect of the sacrum.

SUMMARY OF BACKGROUND DATA

Sacral screw fixation remains a challenging clinical problem because of the unique anatomy of the first sacral vertebra. The anatomic data of S1 have rarely been described in the literature.

METHODS

Sacrums from 50 carefully prepared bony spines were used. Linear measurements included the dimensions of the vertebral body, spinal canal, and pedicle. Pedicle width was measured in two segments, pedicle zones 1 and 2. Angular measurements of the pedicle relative to the sagittal plane were also included.

RESULTS

In pedicle zone 1, the average medial angle of the pedicles was 10.2 degrees for men and 10.7 degrees for women, average width was 10.9 mm for men and 10.4 mm for women, average length of the pedicles was 34.6 mm for men and 34.9 mm for women. In pedicle zone 2, the average medial angle of the pedicles was 39.4 degrees for both men and women, average width was 15.6 mm for men and 14.7 mm for women, average length of the pedicles was 43.7 mm for men, and 41.7 mm for women. The projections of pedicle zones 1 and 2 on the posterior aspect of S1 were determined.

CONCLUSIONS

The investigators proposed the concept of pedicle zones 1 and 2. The safer area for S1 pedicle screw insertion was found in pedicle zone 2.

Response of the lateral meniscus of the dog to wide incision and repair of the meniscotibial ligament

The effects of extensive incision and reattachment of the coronary ligaments on meniscal healing in the canine were examined. Through an extensile exposure to the lateral tibial plateau, nine mongrel dogs underwent wide incision, reflection, and subsequent reattachment of their meniscotibial ligaments. At intervals of 3, 6, and 9 weeks, three dogs were killed and a gross and microscopic evaluation of their menisci and perimeniscal tissues was performed. At 3 weeks, a small region of the central meniscal periphery was found to be devoid of a vascular network. By 6 weeks, the entire peripheral vasculature had reconstituted. No specimen demonstrated histologic evidence of meniscal necrosis or degeneration. Healing occurred by fibrovascular scar.

Anatomy of C7 lateral mass and projection of pedicle axis on its posterior aspect

A specimen study focused on the measurements of C7 lateral mass and pedicle as well as the projection of pedicle axis on the posterior aspect of the lateral mass was done, based on 56 whole clean, dry, well-preserved spines of skeletally mature adults, 32 males and 24 females. Lateral mass widths averaged 11.7 mm. Lateral mass heights averaged 14.8 mm. The average thickness of the lateral mass was 6.8 mm. The average pedicle widths were 6.2 mm, and the average heights were 7.0 mm. Small, but statistically significant differences were found between the averages of the aforementioned dimensions in the male and female groups. The angulation between pedicle axis and the posterior aspect of the lateral mass averaged 107.0 degrees in the transverse plane and 76.2 degrees in the sagittal plane, respectively. Differences in angulations were not significant when compared according to side or sex of group. Distances from the projection point of pedicle axis to a line passing through the mid-line of the transverse process ranged from 2 mm superior to the line to 4.5 mm inferior, with an average 1.2 mm inferior on right side and 0.3 mm inferior on the left. Distances from the pedicular axial projection point to the outer margin of the lateral mass ranged from 0.0 mm to 5.4 mm, with an average 2.4 mm on the right side and 2.9 mm on the left side. Differences of distance related to left or right side were statistically significant, whereas the distances when related to the sex of the group were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteosynthesis of the cervical spine with an anterior plate

Osteosynthesis with an anterior plate is indicated for stabilization of the cervical spine. It is used for reconstruction of the vertebral body following corpectomy and for cervical instability due to fractures, fracture-dislocations, and post-laminectomy. In these situations, a well-keyed anterior graft or posterior fusion alone may be inadequate to attain stability. The authors retrospectively review 25 cases of osteosynthesis of the cervical spine using the AO H-plate. All the patients were stable enough postoperatively to allow early mobilization with a cervicothoracic orthosis. Average follow up was 31.2 months. All the grafts fused; however, complications occurred in 36% of the cases. The majority of these complications did not affect the long-term clinical result. This method involves potential risks to the spinal cord, esophagus, carotid structures, and laryngeal nerve. It should therefore be used in carefully selected cases.

Metaphyseal nonunion: a diagnostic dilemma

Twenty-eight patients with metaphyseal nonunion were evaluated retrospectively. Initially, all patients were thought to have healing of their fractures. Mild pain and/or instability with weightbearing or discomfort localized around the hardware were common symptoms of this nonunion; however, substantial pain was not a predominant feature. In the majority of cases, routine roentgenograms were not helpful in establishing the diagnosis. Overlapping hardware made visualization difficult; furthermore, the presence of a callus gave a false impression of fracture healing. Tomograms were done in 13 patients, but were not helpful in four patients. Stress views and examination under fluoroscopy were reliable means of making this diagnosis, particularly around the knee region. It was done, however, only in a few patients. Subtle changes in the position of hardware or the position of the fragments are also an indication of failure of union. The average time from the initial injury to the diagnosis of nonunion was 36 weeks. Five patients whose pain was attributed to the hardware were found to have a nonunion intraoperatively at time of attempted hardware removal. In one patient, the nonunion was diagnosed during a quadricepsplasty. In two patients, the diagnosis was missed a second time following revision of fixation and bone grafting. Diagnosis of metaphyseal nonunion requires a high index of suspicion, because it occurs among all age groups. It is not as rare as previously described and poses many difficulties. The authors recommend the use of additional studies, including tomograms or stress views, oblique to establish difficult diagrams.

Coronal fracture of the body of the hamate

Fractures of the body of the hamate are unusual. Eleven patients with coronal fractures of the hamate bone, all involving dislocation of the hamate-metacarpal joint, are reported. Routine roentgenograms were not helpful in delineating the presence of the injury in five patients; therefore, fracture diagnosis was not initially made in those patients. The average delay in diagnosis of this group was 10 days. A 30-degree pronated view, tomograms, and computed tomography scans may be necessary in the diagnosis of this injury. This fracture was found to be highly unstable. Ten patients underwent surgery for stabilization of their fractures and restoration of the congruity of the hamate-metacarpal joint. Four patients were treated with open reduction and internal fixation of the fracture. Six patients were treated with closed reduction and percutaneous pinning. All patients treated surgically had maintenance of reduction of their joints. One patient was treated with closed reduction and casting; reduction in this case was lost, and the patient developed residual subluxation of the hamate-metacarpal joint.

The treatment of tibial nonunion with angular deformity using an Ilizarov device

Nine patients with nonunion of the tibia associated with angular deformity were treated using the Ilizarov device. Eight of these went on to heal the nonunion and had acceptable correction of the angular deformity. One patient with an atrophic nonunion and severe bone loss received a below knee amputation. The authors recommend the use of circular ring fixation as an alternative in the treatment of selected cases of stiff nonunion of the tibia combined with angular deformity, particularly if there is active infection, prior use of an external fixator, or poor soft tissue coverage.

Percutaneous computed tomography-guided stabilization of posterior pelvic fractures

Nineteen patients with 21 unstable fractures of the posterior pelvic complex were treated with percutaneous computed tomography (CT)-guided posterior stabilization. CT allowed satisfactory visualization of the fracture and direction and length of the screw. It also allowed the authors to perform the procedure percutaneously, while causing only minimal blood loss. CT cuts that showed the best and safest sites for screw placement were selected. The length and direction of the screw was identified, and the skin entry site was determined. The guide pin was inserted across the fracture or disrupted sacroiliac joint; its correct position was confirmed and a cannulated screw was inserted over the pin. In the majority of patients, a pelvic external fixator was applied in the CT suite. Although assessing the deformity was possible, reduction was difficult but ultimately acceptable. All patients maintained reduction of their sacroiliac complex without loss of fixation, and all fractures healed without clinical or radiographic signs of pelvic instability. This technique was not associated with neurologic injury or deep infection. All but 2 patients returned to preinjury levels of activity and function. Two patients had associated injuries that affected their final functional outcome.

Morphometric evaluation of the cervico-thoracic junction. Practical considerations for posterior fixation of the spine

STUDY DESIGN

Linear and angular measurements were performed on 128 vertebrae (16 spines) from C5 to T5.

OBJECTIVES

Vertebrae were studied to characterize vertebral shape and size changes in the cervico-thoracic region.

SUMMARY OF BACKGROUND DATA

Analysis of vertebral anatomy has been extensive and well characterized. Regions of transitional anatomy necessitate further study due to the often abrupt changes in anatomic relationships.

METHODS

Two observers performed linear and angular measurements including pedicle width, height, and length, as well as pedicle-body, pedicle-lamina, lamina-transverse process, and pedicle-lamina angular measurements. Pedicle axis projection on the posterior aspect of the lamina was also calculated.

RESULTS

The mean pedicle width ranged from 7.8 mm (T1) to 4.4 mm (T5). The body-pedicle angle decreased > 4 degrees per level in the transverse plane, from 50 degrees (C5) to 11 degrees (T5). The axial projection of the pedicle changed throughout the region (compared with level above) and was significant for T1.

CONCLUSIONS

Because of the complexities of the cervico-thoracic junction, additional characterization increases the knowledge of the anatomic relationships in this region.

Evaluation of process fractures of the talus using computed tomography

Coronal computed tomography (CT) scan was used in the evaluation of a fractured process of the talus in 10 patients. Because routine radiographs failed to determine either the size or comminution of the fractured process, CT imaging was used to accurately assess the size, displacement, and comminution of the fractured process. CT scans also showed the extent of subtalar joint involvement, any associated tendon pathology, or additional fractures. In two patients the nature of the injury was initially missed, and CT scan diagnosed a nonunion of the lateral process. In all patients, CT scan altered the management of the fracture or helped in selecting the surgical approach. The authors recommend that coronal CT scans be used in the evaluation of a fractured process of the talus.

Leukotriene B4 (LTB4) receptor antagonists: a series of (hydroxyphenyl)pyrazoles

A series of (hydroxyphenyl)pyrazoles was designed by molecular modeling comparison with the LTB4 structure and prepared for evaluation as LTB4 receptor antagonists, culminating in 4-ethyl-5-[[6-methyl-6-(1H-tetrazol-5-yl)heptyl]oxy]-2-(1H-pyrazol -3- yl)phenol (2). Using an assay for inhibition of specific [3H]LTB4 binding to human PMN, it was found that the pyrazole ring could be methylated at N(1) with little loss of activity while methylation at N(2) reduced activity significantly. The structure-activity relationship of the terminal acid group was investigated. Good activity was found with o- and m-phenylalkanoic acids, chromane carboxylic acid, and tetrazole groups. The best in vitro activity was realized with the pyrazole nitrogen unsubstituted and with a six-carbon chain linking the phenyl ether oxygen to the tetrazole group. Compound 2, having an IC50 of 6.4 +/- 0.8 nM in the binding assay, was selected for further preclinical evaluation.

The perioperative management of protein S deficiency in total hip arthroplasty

Protein S is an antithrombotic plasma protein that serves as a cofactor for another plasma protein, activated protein C. Patients who express a deficiency of protein S have an increased propensity to experience thromboembolic events. These events are often precipitated by factors that may cause thrombosis in nondeficient individuals, particularly in cases of trauma, pregnancy, or surgery. Anticoagulation therapy was instituted in a 45-year-old woman with known protein S deficiency and bilateral total hip arthroplasties.

Anatomic and radiographic considerations in the placement of anterior pelvic external fixator pins

Anatomic and radiographic studies were performed on three cadaveric pelves to define recommendations for better anterior pelvic external fixator pin placement. A thick zone of bone was identified for pin purchase beginning along the iliac crest 2-3 cm posterior to the anterior superior iliac spine (ASIS), and extending 6-8 cm posteriorly along the crest. This zone is hourglass-shaped, and follows the superior gluteal ridge to the superior acetabular region. This zone has a maximal thickness of 4 cm in the supra-acetabular region, and a minimum of 8 mm at the isthmus. Cortical pin penetration is more likely to occur if pin placement begins in the lateral third of the iliac crest, or if the pin is advanced beyond the isthmus of this zone, 5 cm from the crest. Acetabular penetration occurs when the pins are advanced farther than 10.5 cm. Radiographic evaluation demonstrates that only the pelvic outlet view gives the proper orientation of the iliac tables to guide the angle of the pin placement (24 degrees from vertical) and to confirm proper pin placement. Computed tomography (CT) evaluation with "inlet" positioning of the gantry gives complementary information for pin placement.

Subluxation of the cervical spine caused by 3-point seat belt

Cervical spine injuries associated with 3-point (lap-sash) seat belt restraint systems are uncommon and usually without serious sequelae. However, the potential for unstable subluxation or dislocation due to severe flexion-extension mechanism is present and may result in severe disability if not promptly recognized and treated. Such an unstable injury is reported here and was treated with internal fixation. Further attention should be given to the ability of headrests, air bags, and other restraints to protect the cervical spine.

Thoracic and lumbar fractures associated with femoral shaft fractures in the multiple trauma patient. Occult presentations and implications for femoral fracture stabilization

Two-hundred-and-one patients with femoral shaft fractures were identified in a 5 year period at three institutions. Seven patients (3.5%) were found to have associated thoracic or lumbar fractures of various types. All resulted from high-velocity trauma. Four (57%) of these patients had thoracic or lumbar fractures that were undiagnosed on admission and before femoral fracture stabilization. A neurologic deficit persisted in four patients, and the possible contribution of femoral intramedullary rodding with positioning and traction must be considered. A high index of suspicion for thoracic and lumbar fractures is required when evaluating the high velocity trauma patient with a femoral shaft fracture. Presence of the thoracic or lumbar fracture may require initial spine stabilization or alter the method of femoral fracture treatment.

Determination of wrist kinematics using a magnetic tracking device

The objective of this work is to present a method to determine the three-dimensional kinematics of the human wrist joint under physiological loading conditions using a magnetic tracking device. Euler angles were used to determine wrist extension-flexion, radial-ulnar deviation and supination-pronation. The screw displacement axis (SDA) method was used to describe the relative motion between carpal bones. Computer graphics were also used to obtain a better visualization of the three-dimensional motions of the carpal bones. This was accomplished by combining motion data and digitization data describing the geometry of the articular surfaces of the carpal bones. Geometric data included the locations of several points located on the articular surfaces forming the radio-scaphoid and radio-lunate joints. The SDA axes describing the motions of the capitate or the lunate or the scaphoid with respect to the radius during flexion-extension were found almost parallel to the medial-lateral direction. Translations along any SDA did not exceed 2 mm. One can thus consider the motion of each carpal bone as a pure rotation about a screw axis. Also, the SDA axis describing the motion of the capitate with respect to the radius was found to pass through the proximal end of the capitate. The graphical display of carpal motions shows that, as the wrist is flexed, the surface of the lunate within the radio-lunate articulation moves from palmar to dorsal. On the other hand, the palmar-dorsal location of the proximal surface of the scaphoid within the radio-scaphoid articulation remains almost unchanged.

Preoperative CT determination of angles for sacral screw placement

Placement of screws in the sacrum is essential for assuring rigid fixation during instrumentation of the lumbosacral spine. However, the safest approach to obtaining sacral fixation has not been clearly delineated and is complicated by significant interpatient variation in sacral morphology. In the present study, CT evaluation of the S1 pedicle and sacral ala was performed in 10 cadavers and established "average" angles for screw placement. Placement of screws at the "averages" was undertaken and verified on CT. Violation, or near violation, of important anatomic landmarks was found in 4 of 10 specimens. As a result of this study, the authors contend that placement of screws in the sacrum at average angles presents unnecessary risks to important structures. The authors propose that each patient should undergo individualized preoperative CT evaluation to determine safe angles to minimize these risks.

The location of the sacroiliac joint on the outer table of the posterior ilium

Ten cadaveric sacroiliac joints were cleaned of soft tissue and analyzed to determine the average location of the sacroiliac joint on the outer table of the posterior ilium. The superior and inferior limbs of the joint were characterized according to length and width. The longitudinal axis for each limb was determined and located on the outer table of the posterior ilium. The location of the sacroiliac joint was then characterized with respect to established anatomic landmarks. The average lengths of the superior and inferior limbs were 4.4 and 5.6 cm, respectively. The width of each limb averaged 2.0 cm. The average distance from the longitudinal axis of the superior limb to the posterior superior iliac spine was 5.5 cm. The average longitudinal axis of the inferior limb was 1.2 cm superior to the inferior margin of the posterior inferior iliac spine. The angle between the two axes averaged 93 degrees.