Christian W. A. Pfirrmann

Bio: Christian W. A. Pfirrmann is an academic researcher from University of Zurich. The author has contributed to research in topics: Rotator cuff & Magnetic resonance imaging. The author has an hindex of 68, co-authored 291 publications receiving 16321 citations. Previous affiliations of Christian W. A. Pfirrmann include University of California, San Diego & Kantonsspital St. Gallen.

Magnetic resonance classification of lumbar intervertebral disc degeneration.

Abstract: Study design A reliability study was conducted Objectives To develop a classification system for lumbar disc degeneration based on routine magnetic resonance imaging, to investigate the applicability of a simple algorithm, and to assess the reliability of this classification system Summary of background data A standardized nomenclature in the assessment of disc abnormalities is a prerequisite for a comparison of data from different investigations The reliability of the assessment has a crucial influence on the validity of the data Grading systems of disc degeneration based on state of the art magnetic resonance imaging and corresponding reproducibility studies currently are sparse Methods A grading system for lumbar disc degeneration was developed on the basis of the literature An algorithm to assess the grading was developed and optimized by reviewing lumbar magnetic resonance examinations The reliability of the algorithm in depicting intervertebral disc alterations was tested on the magnetic resonance images of 300 lumbar intervertebral discs in 60 patients (33 men and 27 women) with a mean age of 40 years (range, 10-83 years) All scans were analyzed independently by three observers Intra- and interobserver reliabilities were assessed by calculating kappa statistics Results There were 14 Grade I, 82 Grade II, 72 Grade III, 68 Grade IV, and 64 Grade V discs The kappa coefficients for intra- and interobserver agreement were substantial to excellent: intraobserver (kappa range, 084-090) and interobserver (kappa range, 069-081) Complete agreement was obtained, on the average, in 838% of all the discs A difference of one grade occurred in 159% and a difference of two or more grades in 13% of all the cases Conclusion Disc degeneration can be graded reliably on routine T2-weighted magnetic resonance images using the grading system and algorithm presented in this investigation

Clinical outcome after structural failure of rotator cuff repairs.

Abstract: Background: The clinical outcome for patients with documented rerupture after open repair of one or more rotator cuff tendons is not well known. The purpose of this study was to evaluate the clinical outcomes of a consecutive series of rotator cuff reruptures after repair and to provide information concerning the advisability of rotator cuff repair in situations in which there may be a high probability of rerupture. Methods: During prospective follow-up after rotator cuff repairs, we detected, with magnetic resonance imaging, structural failure of the repair in twenty patients, who had a mean age of fifty-nine years at the time of the rotator cuff repair. All patients were clinically examined for the purpose of this report at a mean of thirty-eight months. Results: The reruptures invariably involved the originally torn tendon but were smaller than the original tear in sixteen of the twenty patients. Fatty degeneration of the supraspinatus and infraspinatus muscles, atrophy of the supraspinatus muscle, and glenohumeral osteoarthritis progressed significantly from the preoperative state (p < 0.05). At the time of the most recent follow-up, the subjective shoulder value averaged 75 percent of the value for a normal shoulder. Eleven patients were very satisfied with the result, six were satisfied, two were disappointed, and one was dissatisfied. The mean relative score according to the system of Constant and Murley had increased from 49 percent of the score for a normal shoulder preoperatively to 83 percent postoperatively (p = 0.0001). Pain had decreased significantly, and the ranges of active, pain-free forward elevation and abduction as well as the abduction strength had improved significantly (p < 0.05). The clinical outcome was significantly correlated with the size of the postoperative tear, the stage of postoperative fatty muscle degeneration of the infraspinatus and subscapularis, the postoperative acromiohumeral distance, and the degree of postoperative glenohumeral osteoarthritis (p < 0.05). Conclusions: This study documents that an attempt at rotator cuff repair significantly decreases pain (p = 0.0026) and significantly improves function (p = 0.0005) and strength (p = 0.0137) even if magnetic resonance imaging documents that the repair has failed. This finding suggests that the potential for rerupture should not be considered a formal contraindication to an attempt at repair if optimal functional recovery is the goal of treatment.

Cam and Pincer Femoroacetabular Impingement: Characteristic MR Arthrographic Findings in 50 Patients

Abstract: Purpose: To retrospectively characterize magnetic resonance (MR) arthrographic findings in patients with cam femoroacetabular impingement (FAI) and in those with pincer FAI. Materials and Methods: Institutional review board approval and informed consent were not required. MR arthrographic studies obtained in 50 consecutive patients (30 men, 20 women; mean age, 28.8 years) with FAI were analyzed for labral abnormalities, cartilage lesions, and osseous abnormalities of the acetabular rim. The nonspherical shape of the femoral head at the head-neck junction was measured in eight positions around the femoral head and neck and used to calculate the α angle. Acetabular depth was measured. Surgical diagnosis served as the reference standard. The Wilcoxon rank sum test was used for statistical analysis. Results: At surgery, hips in 33 patients were classified as having cam FAI and hips in 17 patients were classified as having pincer FAI. In both groups, the mean age of patients was 28.8 years. There were signific...

The tibial tuberosity-trochlear groove distance; a comparative study between CT and MRI scanning

Abstract: CT scan is the gold standard for the measurement of the tibial tuberosity-trochlear groove distance (TTTG). The aim of this study was to evaluate the reliability of the TTTG on MRI compared to CT scan. Twelve knees in 11 patients underwent CT and MRI examination for patellofemoral instability or anterior knee pain. Both the bony and the cartilaginous landmarks of the trochlear groove were used for the measurement of the TTTG. The measurements were performed by two experienced musculoskeletal radiologists. The interrater, intermethod and interperiod reliability was calculated using a restricted maximum likelihood estimation and a Bland-Altman analysis. The mean TTTG referenced on bony landmarks was 14.4+/-5.4 mm on CT scans, and 13.9+/-4.5 mm on MR images. The mean TTTG referenced on cartilaginous landmarks was 15.3+/-4.1 mm on CT scans, and 13.5+/-4.6 mm on MR images. An excellent interrater (82%), intermethods (86%), and interperiod (91%) quantitative reliability was found. TTTG can be determined reliably on MRI using either cartilage or bony landmarks. Additional CT scans are not necessary.

Painful Lumbar Disk Derangement: Relevance of Endplate Abnormalities at MR Imaging.

Abstract: PURPOSE: To investigate the predictive value of magnetic resonance (MR) imaging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with discography as the standard. MATERIALS AND METHODS: Fifty patients aged 28–50 years with chronic low back pain and without radicular leg pain underwent prospective clinical examination and sagittal T1- and T2-weighted and transverse T2-weighted MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (116 disks). MR images were evaluated for disk degeneration, a high-signal-intensity zone, and endplate abnormalities. Results of pain provocation at discography were rated independently of the image findings as concordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities. RESULTS: Normal disks on MR images we...

The Outcome and Repair Integrity of Completely Arthroscopically Repaired Large and Massive Rotator Cuff Tears

Abstract: Background: The impact of a recurrent defect on the outcome after rotator cuff repair has been controversial. The purpose of this study was to evaluate the functional and anatomic results after arthroscopic repair of large and massive rotator cuff tears with use of ultrasound as an imaging modality to determine the postoperative integrity of the repair. Methods: Eighteen patients who had complete arthroscopic repair of a tear measuring >2 cm in the transverse dimension were evaluated at a minimum of twelve months after surgery and again at two years after surgery. The evaluation consisted of a standardized history and physical examination as well as calculation of the preoperative and postoperative shoulder scores according to the system of the American Shoulder and Elbow Surgeons. The strength of both shoulders was quantitated postoperatively with use of a portable dynamometer. Ultrasound studies were performed with use of an established and validated protocol at a minimum of twelve months after surgery. Results: Recurrent tears were seen in seventeen of the eighteen patients. Despite the absence of healing at twelve months after surgery, thirteen patients had an American Shoulder and Elbow Surgeons score of ≥90 points. Sixteen patients had an improvement in the functional outcome score, which increased from an average of 48.3 to 84.6 points. Sixteen patients had a decrease in pain, and twelve had no pain. Although eight patients had preoperative forward elevation to <95°, all eighteen regained motion above shoulder level and had an average of 152° of elevation. At the second evaluation, a minimum of twenty-four months after surgery, the average score, according to the system of the American Shoulder and Elbow Surgeons, had decreased to 79.9 points; only nine patients had a score of ≥90 points, and six patients had a score of ≤79 points. The average forward elevation decreased to 142°. Conclusions: Arthroscopic repair of large and massive rotator cuff tears led to a high percentage of recurrent defects. The minimum twelve-month evaluation showed excellent pain relief and improvement in the ability to perform activities of daily living despite the high rate of recurrent defects; however, at a minimum follow-up of two years, the results deteriorated with only twelve patients who had an American Shoulder and Elbow Surgeons score of ≥80. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Gray's Anatomy

Abstract: MEDICAL LITERATURE has been deluged during the past few years with books and papers on penicillin; but a book which has been produced under the general editorship of Sir Alexander Fleming himself represents a complete and authoritative summary of penicillin therapy as it stands today.' The book contains a series of independent contributions by \"experienced and eminent men who have worked with penicillin in Great Britain\". Their opinions and practical methods differ slightly, and there is some overlapping; but these are not disadvantageous, comparison and contrast lending interest to the reading. In the first or general section of the book Fleming contributes two chapters, one on the history and development of penicillin, introducing some interesting sidelights in the romance of discovery, the other on the bacteriological control of penicillin therapy. In both chapters the information is set out in meticulous detail and with a clarity and simplicity which can be enjoyed by all readers. Fleming also gives the right perspective to the place of penicillin amongst the antibiotics and lays down the principles of treatment. Both chapters are well illustrated and are the most outstanding in the book. Included in this first section also are chapters on the chemistry and manufacture of penicillin and its pharmacy, pharmacology and methods of administration. The second section of the book is entirely clinical, giving each author's view on the use of penicillin therapy in a disease or an infection of some particular region of the body. The entire range of peniCillin-sensitive conditions is considered in twenty authoritative and clearly written chapters; these contain many references and illustrations. Dental and veterinary diseases are also given fairly full consideration. The final section is a condensed resume of much of the preceding chapters and is written for. the general practttioner. This chapter is superttuous: it does not contain enough detall to be of much practical value. The book as a Whole, however, will undoubtedly be considered a classical contribution to medical literature and is strongly recommended, not only because of the general interest of its topic, but as a reference book on penicillin therapy of hitherto unequalled excellence. The typography, although conforming to war economy standards, is clear and the paper is good. There is an excellent list of references and the index is satisfactory.

What is intervertebral disc degeneration, and what causes it?

Abstract: and Introduction Abstract Study Design: Review and reinterpretation of existing literature. Objective: To suggest how intervertebral disc degeneration might be distinguished from the physiologic processes of growth, aging, healing, and adaptive remodeling. Summary of Background Data: The research literature concerning disc degeneration is particularly diverse, and there are no accepted definitions to guide biomedical research, or medicolegal practice. Definitions: The process of disc degeneration is an aberrant, cell-mediated response to progressive structural failure. A degenerate disc is one with structural failure combined with accelerated or advanced signs of aging. Early degenerative changes should refer to accelerated age-related changes in a structurally intact disc. Degenerative disc disease should be applied to a degenerate disc that is also painful. Justification: Structural defects such as endplate fracture, radial fissures, and herniation are easily detected, unambiguous markers of impaired disc function. They are not inevitable with age and are more closely related to pain than any other feature of aging discs. Structural failure is irreversible because adult discs have limited healing potential. It also progresses by physical and biologic mechanisms, and, therefore, is a suitable marker for a degenerative process. Biologic progression occurs because structural failure uncouples the local mechanical environment of disc cells from the overall loading of the disc, so that disc cell responses can be inappropriate or aberrant. Animal models confirm that cell-mediated changes always follow structural failure caused by trauma. This definition of disc degeneration simplifies the issue of causality: excessive mechanical loading disrupts a disc's structure and precipitates a cascade of cell-mediated responses, leading to further disruption. Underlying causes of disc degeneration include genetic inheritance, age, inadequate metabolite transport, and loading history, all of which can weaken discs to such an extent that structural failure occurs during the activities of daily living. The other closely related definitions help to distinguish between degenerate and injured discs, and between discs that are and are not painful.

Arthroscopic repair of full-thickness tears of the supraspinatus : does the tendon really heal?

Abstract: Background: Good functional results have been reported for arthroscopic repair of rotator cuff tears, but the rate of tendon-to-bone healing is still unknown. Our hypothesis was that arthroscopic repair of full-thickness supraspinatus tears achieves a rate of complete tendon healing equivalent to those reported in the literature with open or mini-open techniques. Methods: Sixty-five consecutive shoulders with a chronic full-thickness supraspinatus tear were repaired arthroscopically in sixty-five patients with use of a tension-band suture technique. Patients ranged in age from twenty-nine to seventy-nine years. The average duration of follow-up was twenty-nine months. Fifty-one patients (fifty-one shoulders) had a computed tomographic arthrogram, and fourteen had a magnetic resonance imaging scan, performed between six months and three years after surgery. All patients were assessed with regard to function and the strength of the shoulder elevation. Results: The rotator cuff was completely healed and watertight in forty-six (71%) of the sixty-five patients and was partially healed in three. Although the supraspinatus tendon did not heal to the tuberosity in sixteen shoulders, the size of the persistent defect was smaller than the initial tear in fifteen. Sixty-two of the sixty-five patients were satisfied with the result. The Constant score improved from an average (and standard deviation) of 51.6 ± 10.6 points preoperatively to 83.8 ± 10.3 points at the time of the last follow-up evaluation (p < 0.001), and the average University of California at Los Angeles score improved from 11.5 ± 1.1 to 32.3 ± 1.3 (p < 0.001). The average strength of the shoulder elevation was significantly better (p = 0.001) when the tendon had healed (7.3 ± 2.9 kg) than when it had not (4.7 ± 1.9 kg). Factors that were negatively associated with tendon healing were increasing age and associated delamination of the subscapularis or infraspinatus tendon. Only ten (43%) of twenty-three patients over the age of sixty-five years had completely healed tendons (p < 0.001). Conclusions: Arthroscopic repair of an isolated supraspinatus detachment commonly leads to complete tendon healing. The absence of healing of the repaired rotator cuff is associated with inferior strength. Patients over the age of sixty-five years (p = 0.001) and patients with associated delamination of the subscapularis and/or the infraspinatus (p = 0.02) have significantly lower rates of healing. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Classification of age-related changes in lumbar intervertebral discs: 2002 Volvo Award in basic science.

Abstract: STUDY DESIGN A histologic study on age-related changes of the human lumbar intervertebral disc was conducted. OBJECTIVES To investigate comprehensively age-related temporospatial histologic changes in human lumbar intervertebral disc, and to develop a practicable and reliable classification system for age-related histologic disc alteration. SUMMARY OF THE BACKGROUND DATA No comprehensive microscopic analysis of age-related disc changes is available. There is no conceptual morphologic framework for classifying age-related disc changes as a reference basis for more sophisticated molecular biologic analyses of the causative factors of disc aging or premature aging (degeneration). METHODS A total of 180 complete sagittal lumbar motion segment slices obtained from 44 deceased individuals (fetal to 88 years of age) were analyzed with regard to 11 histologic variables for the intervertebral disc and endplate, respectively. In addition, 30 surgical specimens (3 regions each) were investigated with regard to five histologic variables. Based on the semiquantitative analyses of 20,250 histologic variable assessments, a classification system was developed and tested in terms of validity, practicability, and reliability. The classification system was applied to cadaveric and surgical disc specimens not included in the development of the classification system, and the scores were assessed by two additional independent raters. RESULTS A semiquantitative analyses provided clear histologic evidence for the detrimental effect of a diminished blood supply on the endplate, resulting in the tissue breakdown beginning in the nucleus pulposus and starting in the second life decade. Significant temporospatial variations in the presence and abundance of histologic disc alterations were observed across levels, regions, macroscopic degeneration grades, and age groups. A practicable classification system for age-related histologic disc alterations was developed, resulting in moderate to excellent reliability (kappa values, 0.49-0.98) depending on the histologic variable. Application of the classification system to cadaveric and surgical specimens demonstrated a significant correlation with age ( < 0.0001) and macroscopic grade of degeneration ( < 0001). However, substantial data scatter caution against reliance on traditional macroscopic disc grading and favor a histology-based classification system as a reference standard. CONCLUSIONS Histologic disc alterations can reliably be graded based on the proposed classification system providing a morphologic framework for more sophisticated molecular biologic analyses of factors leading to age-related disc changes. Diminished blood supply to the intervertebral disc in the first half of the second life decade appears to initiate tissue breakdown.