Ionomeric cement implants in the middle ear of the baboon (Papio ursinus) as a primate model.

Faced with an inadequate supply of autogenous materials, the otologic surgeon may have to utilize various alloplastic materials to reconstruct bony middle ear structures. Allogenic materials have fallen into disfavor clinically because of the possible spread of infections. Implantation of the hybrid bone substitute ionomeric cement in viscous or hardened physical states into the middle ears of a primate animal model was undertaken in order to be able to approximate as closely as possible conditions found clinically. The posterior meatal wall was replaced by freshly mixed ionomeric cement in nine baboons (Papio ursinus). After repositioning the meatal flap, the residual skin defect was left to secondary epithelialization. After removal of the stapes superstructure, incus and malleus head, a columella of hardened ionomeric cement was trimmed to the appropriate size and inserted between the footplate and the malleus handle. In three cases the prosthesis shaft was fixed in position with freshly mixed cement near the footplate. The time of follow-up ranged from 47 to 277 days. Gross sections were obtained without decalcification (using a Zeiss saw microtome) and stained with Giemsa solution. In no instance was there any spontaneous epithelialization of the external meatus, although occasional granulation was seen to develop at the free edge of the flap and subepithelially. Epithelialization of the alloplastic columellae occurred as early as 42 days post-implantation. Over the middle ears reconstructed with the viscous cement, there was growth of a thickened epithelium that partially tended to granulate. On light microscopy, the bony footplate area was found to be unaffected by the cement that had been applied when still fluid. Our findings indicate that reconstruction of the posterior meatal wall with the viscous ionomeric cement can be useful clinically. The material does not become dislocated but, as with all other alloplastic materials, spontaneous overgrowth of the adjacent meatal skin is unlikely to occur. The early epithelialization of the columellae and their middle ear compatibility and biostability give support to the excellent tolerability of the ionomeric cement. At present, complications occurring during otoneurological application of the material necessitated its commercial withdrawal from the market in May 1995.

Open versus arthroscopic subacromial decompression: analysis of one-year results.

The results of open subacromial decompression (OSD) were compared with arthroscopic subacromial decompression (ASD) after 1 year in 32 subjects (4 bilateral), and the correlation between the two shoulder rating scales for impingement was documented. Patients were evaluated clinically on the modified University of California at Los Angeles (UCLA) shoulder rating scale, and Constant scale. Scapular position and rotation were evaluated as well as a rotation and abduction shoulder strength test using the Cybex II dynamometer. No parameters revealed significant differences between the groups, except for the UCLA score which indicated an advantage for the ASD group (p = 0.046). The OSD group scored 24.5 (5.45) on the UCLA scale and 73.8 (18.9) on the Constant scale, whereas the ASD group scored 28.3 (5.6) and 80.8 (16.4). To study the correlation between both scales, the Pearson correlation product-moment coefficient was calculated and a high correlation (r = 0.81) obtained. Less mobility was found in the operated arm for all parameters, with the exception of glenohumeral abduction in both groups and passive elevation in the OSD group. Only in the OSD group did the scapula in the operated extremity show more abduction of the inferior angle of the scapula. Weaker abduction strength in the operated side was found in the ASD group, whereas in the OSD group there was significantly less adduction and external rotation strength at 180 degrees/s en 240 degrees/s. We conclude that after one year the open group tends to catch up with the arthroscopic patients and that the main benefits after arthroscopic surgery as described in literature are more evident in the shorter period.

Measurements of scapular position and rotation: a reliability study.

Smooth motion of the scapula and humerus with respect to the thorax is essential for shoulder function and abnormalities may indicate clinical entities. Recent studies have made an attempt to devise simple, practical means of quantifying scapular position. The aim of this study was to examine the intra-tester and inter-tester reliability of two methods and to determine if significant differences existed between the dominant versus non-dominant extremity. Seventeen healthy volunteers (4 M; 13 F) were examined by two testers. The tape measurements consisted of the classic methods of Kibler and DiVeta in three sitting postures, expanded by the measurement of the linear distance from the medial border to the thoracic mid-line, and the scapular size measure. The SAS software package was used for data analysis. The Intraclass Correlation Coefficient (ICC) intra-tester reliability ranged between 0.96-0.8 for both methods without significant differences, whereas the ICC for inter-tester reliability ranged between 0.42-0.9 with higher values (moderate and good) for the Kibler technique. In the additional tests high values were also obtained for ICC intra-tester, except for the measurements of the linear distance of the medial border of the scapula to the thoracic mid-line and the distance of the inferior process of the acromion to the third vertebra, both in 90 degrees abduction and internal rotation. The ICC for inter-tester was only acceptable for the DiVeta measurement on 45 degrees abduction. Significant differences were noted between both testers on the following measures: Kibler in 45 degrees abduction, DiVeta in 45 degrees abduction and 90 degrees abduction and the scapular size measure. The comparison of dominant versus non-dominant extremity revealed larger but not significantly different means for the dominant extremity in the classic methods. Significant differences occurred for Tester 1 in the measurement of the distance of the medial border to the thoracic mid-line and Tester 2 in DiVita in 45 degrees abduction. The SEM values never exceeded 1 cm. We believe that the Kibler technique holds promise for further studies, has the advantage of measuring in three positions and with some familiarisation can be reliable. Further research is necessary in patients with pathological conditions.

Relationship between the Newcastle scale and sleep polysomnographic variables in major depression: a controlled study.

In order to investigate the reliability of the endogenous concept of depressive illness with some sleep EEG parameters, we studied 39 male inpatients suffering from a nonbipolar major depressive episode (15 endogenous (MDDE) and 24 nonendogenous (MDDNE)) and 20 age and sex matched normal controls (C). All patients were diagnosed according to the Research Diagnostic Criteria (RDC) and the endogenous character of the episode was assessed with the Newcastle Endogenous Depression Diagnostic Index. We found significant differences for the following variables between the three groups (MDDE, MDDNE and C): sleep period time (SPT), REM latency, stage II, slow wave sleep (SWS), REM latency expressed as a continuous variable and REM latency expressed as a dichotomizing variable with a threshold of 50 min. These variables were used to compare the endogenous and the nonendogenous depressed patients and also the major depressed patients and the normal controls. Significant differences were observed between all depressed patients and control subjects for amount of SWS and REM latency which were both reduced in endogenous and nonendogenous depressed patients. No significant difference was observed between endogenous and nonendogenous depressed patients, except for the REM latency expressed with a threshold of 50 min (more frequently observed in endogenous depressed patients). Our data support the observation that SWS and REM latency are decreased in major depressive patients. However, in this age and sex controlled study, subtyping nonbipolar major depressive disorder for an endogenous character by the Newcastle Endogenous Depression Diagnostic Index (NEDDI) did not reveal further significant differences for sleep EEG variables, except for the shortening of the REM latency expressed as a dichotomizing variable.

Ionogran--an ionomeric micro implant in bone tumour reconstruction. A clinical evaluation.

A new implant material, Ionogran (Ionos, Medizinische Produkte GmbH & Co. K.G., Germany), is evaluated in a series of 60 cases requiring augmented bone grafting for major bone defects. The material, an ionomeric porous micro implant (IMI), is stable, non-degradable, osteoconductive and biocompatible. It promotes the formation of osteoid and displays a dynamic surface activity which stimulates the process of repair. In the compromised situation of a large cavity following curettage and cryotherapy, Ionogran when mixed with a mulch of autogenous cancellous bone is a valuable filler, providing a direct osteoid bond with host bone, and a permanent scaffold which maintains shape, length and form of the affected part. It replaces allogenic bone grafts and the problems associated with that technique.

Bone cell interactions with a granular glass-ionomer bone substitute material: in vivo and in vitro culture models.

The interface between bone and a synthetic bone substitute constructed from glass-ionomer cement (ionomeric microimplant) was studied in diffusion chambers implanted in a primate baboon model (Papio ursinus) and in in vitro primary bone organ cultures derived from neonate rat calvaria. In both models osteoblast-like cells colonized the surface of the implant producing a collagenous extracellular matrix. An electron-dense bonding zone similar to that reported for hydroxyapatite and titanium was seen in both models but was a more constant feature of the tissue/implant interface in calvarial culture.

A glass ionomer for reconstructive surgery. Ionogran--an ionomeric micro implant. A biological evaluation.

A porous glass-ionomer (Ionogran) was evaluated and compared to hydroxyapatite Interpore 200. In an in-vivo screening test procedure, microfilter diffusion chambers embedded on the tibial surfaces of adult baboons were used to evaluate cell survival, cell regeneration and cell differentiation. In a bulk testing procedure a standardized bone core was removed from the tibia through the knee joint and the material exposed to the defense mechanisms of the system. Both materials were found to be biocompatible, non-toxic and did not inhibit cell proliferation in the enclosed environment of diffusion chambers. Histological response and cell arrangement within the chambers containing Ionogran were similar to that of the controls with cancellous bone only. Highly specialized haemopoietic tissues were in direct contact with the Ionogran. In the presence of hydroxyapatite new bone was actively formed. Haemopoietic elements were never found in contact with the hydroxyapatite. In the bulk testing procedure, the general histological appearance was that of a reactive tissue response to a low grade persistent stimulation coupled to surface degradation products. The Ionogran was found to be stable, osteo-conductive and promoted osteoid formation when in contact with bone. From a clinical point of view the material could serve as a permanent scaffold, maintaining form, and will be of value in bone reconstructive procedures.

Tendon response to trauma and its possible clinical application. An experimental study in primates.

A study was undertaken to determine the response of tendon to trauma, and to establish the precise role of the intrinsic tendon cells vis-à-vis the paratendinous tissues in the healing process. It was found that tendon collagen has the ability to resist gross trauma and that tendons possess an inherent ability to regenerate and heal. The high rate of proliferation of synovial cells and the initial much lower rate of activity of intrinsic tendon cells have a direct bearing on the end result of the repair process. The principle of pre-stimulation of the tendon to improve the intrinsic vasculature and hence the rate and the quality of the healing process has been applied with promising, indeed striking, effect.

Ionos bone cement (glass-ionomer): an experimental and clinical evaluation in joint replacement.

Ionos bone cement (glass-ionomer) was evaluated in total joint replacement procedures, initially in a baboon model, and finally in a highly selected group of patients in whom polymethyl methacrylate cement was contra-indicated. It was found that the cement has no inhibitory effect on bone tissue development. It is effectively incorporated into the bone, both structurally and functionally without the interposition of fibrous tissue. Under the functional stress situation in baboon hip and knee arthroplasties, the bone and marrow in direct contact with the cement responded favourably. A direct bone bond was demonstrated. The clinical results achieved were satisfactory, notwithstanding the complexity of the clinical problems included in the series. The continued clinical evaluation on a controlled basis has been shown to be well-justified.

Thermotoxicity of palacos cement. Clinical observation.

In total hip joint replacement with cemented prostheses, Palacos (polymethyl methacrylate, PMMA) involves a high perioperative risk for the patient, on account of the effects on both the systemic and the pulmonary circulation. Data were assembled retrospectively from the records of 203 patients who underwent hip joint operation with Palacos implantation in the Inner City Surgical Clinic and the Surgical Polyclinic of the University of Munich from 1982 to 1986. In the hemiarthroplasty series, hemiarthroplasty was performed in 61% of patients in risk group III, whereas in the risk groups I and II it was done in 31% of cases. The mortality following hemiarthroplasty was greater than that following implantation of total prostheses in risk groups I and II. In risk groups II and III the mortality was 17% with surgery on the day of injury, lower, at only 10%, when the operation was performed on the day after injury, and markedly higher, at 31% and 38%, respectively, when surgery was postponed to the 2nd or 3rd day. It has been shown in burn research that the prostanoid levels in the plasma of untreated animals show a typical curve with two peaks, the first on the day of the injury and the second on the 3rd day after injury. Our observations support the assumption that the effect of trauma and surgical treatment are complementary.

Primary tendon healing. An experimental study.

The management of a severed tendon within the digital sheath continues to present a formidable challenge. The major problem is one of excessive scar tissue formation. It was found experimentally in severed and partially divided tendons that the source of the blood supply, i.e. the vasculature in the tendon proper, will promote healing through the primary tissue (tenoblast) of the tendon itself, whereas the blood supply and granulation tissue from the damaged area of the flexor sheath leads to fibrous (scar) tissue formation. In this study of tendon repair special attention was paid to a suturing procedure which would have the least effect on the intrinsic blood supply to the severed ends. It was found that the basic requirement in successful tendon repair was to approximate and not to strangulate, and to minimize trauma to the flexor sheath which is the main source of scar tissue.

Allogenic bone transplantation. Part I. A review of the status of allogenic bone banks.

The various methods of preserving bone for implantation are reviewed. Biological assay systems to determine the physiological and osteogenic potential of the implant are discussed. Sterilization remains the major problem. The influence of high-energy irradiation of freeze-dried bone is still uncertain. Experimentally and clinically it was found that the immunological status of the freeze-dried allo-implant is biocompatible.

Allogenic bone transplantation. Part II. A histological and radiographic study of freeze-dried bone allo-implants in primates.

A histological and radiographic study was undertaken to evaluate freeze-dried bone as an alternative to the autogenous transplant. The source of the blood supply from the surrounding soft tissues or from the host bone bed can be the determining factor in the incorporation of the implant/transplant. The testing of the osteogenic potential in non-orthotopic sites in primates is an inappropriate method. Freeze-dried allograft bone is an inert, rapidly immobilized biodegradable implant which can also serve a structural function.

Condylar hyperplasia. A case for early treatment.

Clinical experience indicates that the condylar growth centre is an important factor in the dimensional changes of the face up to the 10th year. Thereafter muscular and functional occlusion determine the ultimate facial form. condylar hyperplasia should be recognised at a very early age. To achieve an acceptable result early treatment of facial asymmetry related to condylar hyperplasia should be considered in the most active growth phase of the mandible (6-8 years).