Quantification of intact quadriceps tendon, quadriceps tendon insertion, and suprapatellar fat pad: MR arthrography, anatomy, and cryosections in the sagittal plane.

OBJECTIVE: The purpose of this study was to quantify quadriceps tendon length, thickness, and insertion in relation to the suprapatellar fat pad. SUBJECTS AND METHODS: We used three methods to analyze the anatomy of intact quadriceps tendons and insertions into the patellar base: MR arthrography (53 knees with intact extensor mechanisms), gross anatomy (16 cadaveric knees), and cryosections (four cadaveric knees). With an electronic cursor, two observers independently quantified the extensor mechanism on midline sagittal T1-weighted spin-echo sequences acquired on a low-field-strength (0.23 T) scanner. RESULTS: On MR arthrograms, quadriceps tendon length, determined from the superior patellar pole to the most superior part of the suprapatellar recess, measured 49 +/- 7 mm in women and 50 +/- 9 mm in men. Thickness of quadriceps tendon at three sites (suprapatellar recess, center, and superior patellar pole) measured 7 +/- 1 mm in women and 8 +/- 1 mm in men. Thickness was significantly larger in men at all measurement locations. Quadriceps tendon insertion and the suprapatellar fat pad along the patellar base measured 16 +/- 2 and 6 +/- 2 mm, respectively, in women, and 18 +/- 3 and 7 +/- 2 mm, respectively, in men. CONCLUSION: On midline MR images, sagittal thickness of the quadriceps tendon and its insertion was significantly larger in men than in women. The prevalence of the suprapatellar fat pad was 100%.

Anatomy and surface geometry of the patellofemoral joint in the axial plane.

We studied the anatomy of the patellofemoral joint in the axial plane on cryosections from a cadaver knee and on MR arthrotomograms from 30 patients. The cryosections revealed differences in the geometry and anatomy of the surface of the articular cartilage and corresponding subchondral osseous contours of the patellofemoral joint. On the MR arthrotomograms the surface geometry of the cartilage matched the osseous contour of the patella in only four of the 30 knees. The articular cartilaginous surface of the intercondylar sulcus and corresponding osseous contour of the femoral trochlea matched in only seven knees. Since MR arthrotomography can distinguish between the surface geometry of the articular cartilage and subchondral osseous anatomy of the patellofemoral joint, it allows the surgeon and the radiologist to appraise the true articulating surfaces. We therefore recommend MR arthrotomography as the imaging technique of choice.

Outcome after limited posterior surgery for thoracic and lumbar spine metastases.

The efficacy of 'limited posterior surgery' for metastases in the thoracic and lumbar spine was studied prospectively in 51 patients (32 men and 19 women, mean age 64 years). The most common primary tumors were prostate, breast, and renal carcinoma, 37 patients had metastases in the thoracic spine and 14 in the lumbar spine. Indications for surgery were severe pain or neurologic deficit. Of the 46 patients with neurologic symptoms, 25 were unable to walk. Surgery was confined to direct or indirect decompression and stabilization with a pedicle screw fixator over few segments as possible. Pain, as well as a variety of functional performance parameters and residential status were registered preoperatively and after surgery at 3, 6, 9, and 12 months, and at 6-monthly intervals thereafter. Pain was rated by the patient on a Visual Analog Scale, and functional performance was assessed with the Eastern Co-operative Oncology Group (ECOG) Performance Status Scale. We had no perioperative neurologic deterioration or death. Nineteen of the 25 nonambulatory patients regained their walking ability. Postoperative pain relief was significant and lasting over time. Nearly half of the patients attained improvement in functional performance. The median survival was 8 months. Older age and intact postoperative walking ability were positive factors for survival.

Indirect spinal canal decompression in burst fractures treated with pedicle screw instrumentation.

STUDY DESIGN: Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator. OBJECTIVES: Assessment of the efficacy of "indirect" spinal canal decompression in a large series of burst fractures. SUMMARY OF BACKGROUND DATA: Up to 50% of burst fractures cause neurologic impairment. Reduction and posterior instrumentation is the most common surgical treatment. This also reduces spinal canal encroachment by indirect decompression. No consensus exists as to the consistency and adequacy of such indirect decompression. METHODS: Spinal canal areas were measured on preoperative and postoperative computed tomography scans. The degree of encroachment was compared with clinical and radiographic variables for possible correlation. RESULTS: Spinal canal encroachment was more severe among patients with neurologic deficits than among the neurologically intact. Postoperatively, mean encroachment was reduced from 35% to 12% at T12, from 37% to 17% at L1, and from 52% to 35% at L2. Loss (and postoperative restoration) of anterior vertebral height correlated best with the degree of canal encroachment (and its reduction), especially in Denis Type A burst fractures. In Denis Type B fractures, canal compromise usually was less severe and fragment reduction better in patients older than 40 years of age than in younger patients. CONCLUSIONS: Indirect decompression in burst fractures averages about half of the preexisting encroachment. Results are usually better at T12 and L1 than at L2. Additional or secondary decompression is rarely indicated if these fractures are treated early and by experienced surgeons. Burst Type B fractures in patients older versus younger than 40 years of age differ in many respects.

Normal anatomy of the hand and wrist.

An understanding of the anatomy is invaluable when such small structures as described here are to be evaluated. Because MR imaging reveals greater detail, radiologists are obliged to use the information available to benefit the clinician and the patient. A working knowledge of the anatomic elements and their nomenclature also engenders confidence in the imager on the part of the hand surgeon. This discussion serves as the basis for meaningful comprehension of the pathologic entities that are presented in the articles that follow.

The normal prostate and periprostatic structures: correlation between MR images made with an endorectal coil and cadaveric microtome sections.

This pictorial essay illustrates the normal prostate and periprostatic structures seen on MR images obtained with an endorectal coil and correlates them with anatomic structures identified on serial microtome sections of a frozen human cadaver. The correlation shows that high-resolution MR imaging allows detailed visualization of normal anatomic structures. The ability to identify the normal anatomy and to recognize pathologic alterations provides valuable information concerning clinical decision making for both benign and malignant prostatic disease.

Analysis of peridural scar formation and its prevention after lumbar laminotomy and discectomy in dogs.

STUDY DESIGN: Peridural fibrosis after lumbar laminectomy and discectomy has been implicated (not proven) as one of the factors that contribute to continuing or recurrent radicular and/or low back pain. This animal experimental study was designed to unequivocally show the stages in the development of scar tissue and to what extent, if any, scar tissue development is influenced by interposing fat grafts and Na hyaluronate of different molecular weights. METHODS: A four-level unilateral lumbar laminotomy, anular fenestration, and nucleotomy was performed in 11 dogs. In each dog, levels were selected at random: one to serve as an empty control and three to insert the following: a fat graft, a viscous (1.9%) solution of Na hyaluronate, and a 1% high molecular weight solution of Na hyaluronate solution. The animals were killed at 1 day, 2 days, and 1, 2, 4, and 12 weeks postoperatively. Immediately after the dogs were killed, the lumbar spines were frozen in situ with dry ice, the lumbar spines were harvested and sectioned with a cryomicrotome. Close-up photographs taken at submillimeter intervals at each level were digitized and postprocessed with a computer. RESULTS: In the early postoperative period a hematoma was found in the pathway of the surgical dissection. During a 2-4 week period, this hematoma was replaced by a thick, white fibrotic tissue mass. Fibrosis was markedly less pronounced at the hyaluronate levels, especially the high molecular weight subset. Two-way statistical analysis of variance without replications revealed significantly less scar formation at the 0.05 level in the hyaluronate vs. the control segments. Dunnett's test, comparing each group individually with the control, revealed no difference between the fat groups and the control subjects. There was a significant difference between 1.9% Na hyaluronate and control. CONCLUSIONS: Viscous hyaluronate solution with its semifluid properties coats the nerve roots and dura anteriorly and posteriorly and reduces peridural fibrosis in the critical anterior region where adhesions form between the nerve root and anulus fibrosus.

Pathoanatomical and radiographic findings in spinal breast cancer metastases.

Spine specimens infested with breast cancer metastases, ranging from localized seed of small tumor deposits to massive invasion and vertebral collapse, were frozen in situ, removed, examined with both conventional radiography and high resolution computed tomography (CT), and then studied in great detail by serial cryoplaning. The majority of metastases in the total of 53.5 vertebrae were lytic, and most were in close contact with the vertebral wall or the endplates. Depressions and defects of the endplates were associated with compensatory expansion of the intervertebral discs. Although lytic lesions abutting endplate defects had the radiological appearance of metastases, all contained herniated disc material rather than tumor. Only four of the 29 grossly destroyed and collapsed vertebrae showed extrusion of the posterior vertebral wall into the spinal canal. Tumor growth in the epidural space was rare. There were no macroscopical reactive changes of the osseoligamentous or neurovascular spinal elements to the metastases, but abnormalities of the posterior elements (kissing spines, facet joint subluxation, and pars interarticularis failure) were common.

Findings and outcome in whiplash-type neck distortions.

STUDY DESIGN: The authors assessed the clinical and imaging findings and late outcome in 50 patients with whiplash-type neck distortions (17 men, 33 women, mean age 33 years). SUMMARY OF BACKGROUND DATA: Early symptoms are neck pain, stiffness, and sometimes radiating pain; later bizarre symptomatology poses intricate clinical and medicolegal problems. Pathoanatomic studies indicate that soft tissue injuries may be overlooked. METHODS: Repeated clinical and radiographic examinations (plain and flexion-extension radiograms and contrast magnetic resonance imaging evaluated with a new grading system); surgical findings; follow-up were performed after 1 and 5 years by an independent observer neurologist. RESULTS: Neck pain persisted in 24 patients; radiating pain developed within 6 weeks in 19 patients. Two patients with segmental instability had posterior fusions and complete pain relief. Eight patients with severe radiating pain and large disc protrusions on magnetic resonance had nine surgically confirmed fresh disc herniations. Discectomy and fusion alleviated pain in these patients, whereas symptoms largely persisted in the conservatively treated patients. CONCLUSIONS: A high incidence of discoligamentous injuries was found in whiplash-type distortions. Most patients with severe persisting radiating pain had large disc protrusions on MRI that were confirmed as herniations at surgery. Neck and radiating pain were alleviated by early disc excision and fusion.

Anatomical and morphometric studies in posterior cervical spinal screw-plate systems.

To study potential risks for complications in posterior articular pillar plate fixation, screw-plate systems of Roy-Camille, Louis, and Magerl were implanted into the cervical spines of cadavers under authentic operation theater conditions and in vitro into isolated spine specimens according to the inaugurators' recommendations with regard to plate and screw positioning. We compared these systems with the method of our preference, using the small AO compression plate and monitoring each screw insertion fluoroscopically. The screws were directed toward the projection of the pedicles, and their length was measured individually. Radiographic analysis of the specimens and cryoplaning after implant removal and casting of the screw-plate cavities showed significant differences of the four systems with respect to effective screw length, possible and desirable screw trajectories, and risk for injuries of the facet joints, foraminal neurovascular elements, and vertebral artery, as well as mechanical conflict of the plate with adjacent facet joints.

Spinal canal remodelling after stabilization of thoracolumbar burst fractures.

Spinal canal areas were measured prospectively in 22 consecutive burst fractures of the thoracolumbar junction, preoperatively, within 1 week postoperatively and 1 year after operation. Preoperative canal encroachment averaged 38% (range 10%-70%) of the estimated original area. The 11 patients with neurological impairment had a significantly more severe initial canal encroachment (mean 48%) than those who were neurologically intact (mean 33%). Postoperatively, canal encroachment had decreased to a mean of 18% (range 0%-62%). Within 12 to 15 months postoperatively, canal encroachment was further reduced by resorption of bone fragments to a mean of 2%. The largest observed remaining encroachment was 29%. The amount of bone resorption correlated significantly with the persistent postoperative encroachment. A critical appraisal of the methods used to assess the pre-fracture canal area revealed that reconstructing the vertebral foramen of the fractured vertebra on CT scans substantially overrated the original area as compared with averaging the canal area of the two adjacent vertebrae.

Droloxifene, a new antiestrogen: its role in metastatic breast cancer.

Droloxifene, a new antiestrogen, has theoretical advantages over tamoxifen based on preclinical data. These include higher affinity to the estrogen receptor, higher antiestrogenic to estrogenic ratio, and more effective inhibition of cell growth and division in ER positive cell lines, as well as less toxicity, including reduced carcinogenicity in animal models. Droloxifene also exhibits more rapid pharmacokinetics, reaching peak concentrations and being eliminated much more rapidly than tamoxifen. A phase II study compared droloxifene in dosages of 20, 40, and 100 mg daily in postmenopausal women with metastatic, or inoperable recurrent, or primary locoregional breast cancer who had not received prior hormonal therapy. Of 369 patients randomized, 292 were eligible and 268 evaluable for response. Response rates (CR + PR) were 30% in the 20 mg group, 47% in the 40 mg group, and 44% in the 100 mg group (40 mg vs 20 mg, p = 0.02; 100 mg vs 20 mg, p = 0.04; pooled 40 + 100 mg vs 20 mg, p = 0.01). Median response duration also favoured the higher dosages (20 mg group = 12 months; 40 mg group = 15 months; 100 mg group = 18 months). When adjusted for prognostic factors, time to progression was significantly better for the 100 mg (p = 0.01) and the 40 mg (p = 0.02) group compared to the 20 mg group. Droloxifene increased SHBG and suppressed FSH at all dosages and suppressed LH at the 40 and 100 mg dosages. These hormonal effects increased with increasing dosage. Short-term toxicity was generally mild, and similar to that seen with other antiestrogens. Droloxifene appears active and tolerable. It may have a particular role in situations in which rapid pharmacokinetics, or an increased antiestrogenic to estrogenic ratio, are required.

Tibial attachment area of the anterior cruciate ligament in the extended knee position. Anatomy and cryosections in vitro complemented by magnetic resonance arthrography in vivo.

Knowledge of the anatomy of the anterior cruciate ligament (ACL), including its course and orientation in relation to the roof of the intercondylar fossa, is a prerequisite for successful intra-articular ACL reconstruction. To attain precision placement of the tibial attachment site and to avoid graft/roof conflict in the extended knee position, we assessed the anteroposterior tibial insertion of the ACL in the midsagittal plane of the extended knee. We measured the anterior-posterior (AP) limits and the center of the tibial attachment area of the ACL from the anterior tibial margin. The inclination angle of the intercondylar fossa roof was measured with respect to the shaft axis of the femur. The tibial attachment area of the ACL was determined in ten cadaveric knees. Using the cryoplaning technique, we determined the tibial attachment of the ACL in five knees. Using contrast magnetic resonance arthrography (MRA), we measured the tibial insertion of the ACL in 35 patients (23 male and 12 female) with intact ACLs. The total AP midsagittal diameter of the tibia averaged 51.0 +/- 5.8 mm in the cadaveric knees, 49 mm on cryosections, and 53.7 mm in men and 49.0 mm in women with MRA. The average anterior limit of the ACL, measured from the anterior tibial margin, was 14 +/- 4.2 mm in the cadaveric knees, 12.1 mm at cryosectional anatomy, and 15.2 mm in men and 13.4 mm in women with MRA.(ABSTRACT TRUNCATED AT 250 WORDS)

[Knee injuries in alpine sports]. / Kneiverletzungen beim alpinen Skisport.

Knowledge of functional anatomy and cryo-sectional microanatomy are prerequisites for successful intra-articular arthroscopy, assisted ACL reconstruction in documented anterior subluxation of the tibia.

Current role of MR imaging in the staging of adenocarcinoma of the prostate.

Surgical cure of adenocarcinoma of the prostate (ACP) is possible in over 80% of cases when the disease is confined to the gland capsule. The endorectal probe for magnetic resonance (MR) imaging has increased resolution of the prostate gland and capsule, which has improved the sensitivity and specificity for staging ACP (.65 sensitivity, .69 specificity for body coil; .87 sensitivity, .85 specificity for the endorectal coil). Normal glandular regions in the peripheral zone and central zone have significantly higher citrate levels than ACP and fibromuscular and fibrous benign prostatic hyperplasia at proton spectroscopy. ACP has a higher phosphomonoester-phosphocreatine ratio than normal glandular tissue at phosphorus spectroscopy. The combination of endorectal coil MR imaging for local spread, and body coil MR imaging for advanced disease, makes MR imaging the premier imaging modality for the preoperative staging of ACP.

CT analysis of pedicles and screw tracts after implant removal in thoracolumbar fractures.

Twenty-one burst fractures of the thoracolumbar junction were stabilized with a transpedicular fixator by surgeons experienced in this technique. Screws 5 or 6 mm in diameter were used. After the removal of the device 1 year postsurgery, axial CT scans were obtained of the instrumented vertebrae. Eighty-two pedicles were examined. In 16 pedicles, medial or lateral cortical defects were found. Five screws had intruded into the spinal canal by a maximum of 3.5 mm. In 48 pedicles a correlative comparison with the preoperative examinations was possible. Compared with the dimensions of the pedicles on the preoperative CT scans, 31 had increased in width, and 14 showed deformation indicative of fractures of the lateral pedicle wall. When the screw diameter exceeded 65% of the pedicles' outer diameter, 85% of the pedicles expanded. One of four screws had penetrated the anterior wall of the vertebra. Pedicle screw penetration on the left side above L2 poses potential risk of erosion of the aorta. The use of pedicle screws at the thoracolumbar junction by experienced surgeons carries some risk for malplacement and neurological damage. Mismatch between pedicle dimension and screw size results in pedicle expansion and lateral wall fractures, probably during screw insertion. Preoperative CT examinations should be used to help in choosing appropriate screw diameter presurgery.

Anatomic and technical considerations of pedicle screw fixation.

Pedicle screw systems provide significant and, in many cases, improved and previously unattainable spinal fixation. However, pedicle screw systems represent difficult surgical techniques involving several potential problems and complications. Only by detailed knowledge of the anatomy of the spine, with a clear understanding of the pedicle screw systems implementation, can the risks of complications be minimized.

Vertebral burst fractures: an experimental, morphologic, and radiographic study.

Spinal burst fractures are produced by rapid compressive loading, and may result in spinal cord injury from bone fragments forced from the vertebral body into the spinal canal. This fracture is one of the most difficult injuries of the spine to successfully treat, in part because the biomechanics of reduction and the exact mechanism by which the distraction forces are transmitted to the intracanal fragments of the burst fracture have not been adequately investigated. The authors developed a reproducible technique for creating these fractures in vitro. The fractures produced were identical to those observed in clinical practice, and were used for investigating the mechanics of this fracture and its reduction. This work describes the pathologic anatomy of the burst fracture both on the gross structure and also on microtome sections of the vertebrae, and examines the biomechanics of fracture reduction. The margins of the vertebral bone fragment, which was forced posteriorly into the spinal canal during fracture, were noted to extend far laterally beyond the pedicles. The authors also found extensive damage not only to the disc above the injured level, but also to that below, explaining the clinical observation that disc degeneration frequently occurs at both levels. Examination of anatomic data provided by microtome section supported the hypothesis that the fibers that actually reduce the intracanal fragment originate in the anulus of the superior vertebra in the midportion of the endplate and insert into the lateral margins of the intracanal fragment. Investigations using magnetic resonance imaging confirmed that these obliquely directed fibers account for the indirect reduction of the fragment. The authors' studies demonstrate that the posterior longitudinal ligament provides only a minor contribution in the reduction of the fracture in comparison to the attachments of the posterior portion of the anulus fibrosus. The forces required to reduce this fragment were studied. Distraction was found to be the predominant force required for indirect posterior reduction. This was confirmed by a series of tests using devices that provided segmental fixation. The application of uniform distraction forces was most effective in the posterior reduction of the intracanal fragment.