Weight-bearing test of traumatic triangular fibrocartilage complex lesion with unstable radioulnar joint.

BACKGROUND: Ulnar-sided wrist pain might be caused by a lesion of the triangular fibrocartilage complex (TFCC). Patients with TFCC lesion may show an instability of the distal radioulnar joint (DRUJ). Before arthroscopic assessment, conservative therapy using a brace or splint may result in alleviation of symptoms. The results of our previous study showed that patients with a traumatic TFCC lesion and instability of the DRUJ had the smallest weight-bearing capacity and had the largest increase in application of the wrist brace (WristWidget). PURPOSE: In this prospective study, we wanted to test if the weight-bearing capacity with and without the wrist brace can be used as a diagnostic tool to differentiate between patients with traumatic TFCC lesion and instability of the DRUJ. We tested if patients with traumatic TFCC lesion and instability of the DRUJ (1) have a lower weight-bearing capacity and (2) show a higher increase of weight-bearing capacity after application of a wrist brace compared to all other types of injury. STUDY DESIGN: This was a prospective cohort study. METHODS: Forty-eight patients presented to an outpatient clinic with suspected TFCC lesion. We measured the dynamic weight-bearing capacity of both hands with and without the wrist brace (WristWidget) by letting the patients lean on an analog scale with extended arm and wrist. The stability of the DRUJ was assessed by clinical examination by a hand surgeon preoperatively and intraoperatively. Forty-five patients received an arthroscopy and were included in the analysis. During arthroscopy, the surgeon determined if there was a traumatic TFCC lesion and DRUJ instability. Patients with a traumatic lesion of the TFCC and DRUJ instability were compared to all other cases. We used the t-test for normally distributed values, Mann-Whitney U test for nonnormally distributed values, and the Chi-square test for categorical variables, respectively Fisher's exact if the expected cell count was less than five. RESULTS: Patients with a traumatic TFCC lesion and DRUJ instability had a higher weight-bearing capacity (22.8 kg) than all other cases (13.8 kg; p < 0.01). This is in contrast to our previous study, in which patients with a traumatic lesion of the TFCC had the tendency to show lower values of weight-bearing capacity than those with a degenerative lesion. While the wrist brace was worn, the relative gain was not significantly lower in patients with traumatic TFCC lesions and DRUJ instability compared to all other cases (21% vs 54%, p = 0.16). All included cases showed the same absolute increase of about 4 kg in weight-bearing capacity with the wrist brace (p = 0.93) CONCLUSIONS: The weight-bearing test cannot be used to identify patients with traumatic TFCC lesion and DRUJ instability among those with suspected TFCC lesion. The results of our previous study could be confirmed that the weight-bearing capacity on the injured side was higher with brace than without.

Intramedullary Single-Kirschner-Wire Fixation in Displaced Fractures of the Fifth Metacarpal Neck (Boxer's Fracture).

The fracture of the fifth metacarpal neck (also called a boxer's fracture) is the most common fracture of the hand1,3. Displaced fractures often result in volar angulation of the metacarpal head, shortening, and residual malrotation4-7. The present video article demonstrates the steps of performing intramedullary single-Kirschner-wire fixation of the fifth metacarpal neck1, with the aim of the procedure being to achieve a closed reduction and internal stabilization of such a fracture. Although many fractures can be treated with a splint only, surgery should be performed in patients with excessive volar angulation, relevant shortening, or rotational deformity5-7. Description: For this procedure, the injured arm of the patient is placed on an arm table. The incision is made 1 to 2 cm longitudinally over the ulnar base of the fifth metacarpal bone. The cortical bone is opened with an awl, and a bent 1.6-mm Kirschner wire is inserted into the medullary canal. After reaching the fracture region, the fracture is anatomically reduced. The Kirschner wire is then advanced into the head of the fifth metacarpal, securing the reduction. Malrotation can be addressed in this stage by rotating the wire under fluoroscopic control. After ensuring anatomical reduction clinically and by fluoroscopy, the wire is shortened under the skin, followed by closure of the incision. We utilize a mid-hand brace for splinting. Alternatives: Nonoperative treatment is common for fifth metacarpal neck fractures in the absence of malrotation, excessive angulation, and shortening. Other surgical techniques include a similar procedure that involves the use of multiple Kirschner wires, plate fixation, transverse Kirschner wire pinning, and, less commonly, retrograde headless screw fixation2,7-9. Rationale: The main advantage of this technique is the preservation of the metacarpophalangeal joint and the minimal soft-tissue damage. Additionally, the use of a single Kirschner wire provides stability at low cost. With some experience, this surgery can be performed within 20 minutes1,9. Expected Outcomes: This procedure provides good fracture reduction and stabilization8. The outcome is usually satisfactory, with very low Disabilities of the Arm, Shoulder, and Hand scores1. Malrotation, angulation, and shortening are sufficiently addressed, and the technique shows the same results as fixation performed with use of 2 intramedullary wires. Important Tips: Bending the Kirschner wire to ensure easy gliding in the medullary canal provides the opportunity to reduce the metacarpal neck once the wire is safely in the head.Aim distally as you open the cortical bone with the awl in order to facilitate the insertion of the Kirschner wire.The primary reduction should be made manually, not by the wire. Subacute fractures and substantially displaced fractures require direct force for a satisfactory reduction, which cannot be achieved by rotation of the wire only.The cortical bone on the metacarpal head is very thin. Take care not to drive the Kirschner wire through the cortical bone and into the joint.Shorten the wire under the skin approximately 1 cm above the bone surface; this ensures easy removal and prevents skin irritation. Acronyms and Abbreviations: K-wire = Kirschner wire.

Comparison of Calculated Skin Doses in Cineradiography and Four Dimensional Kinematic Computed Tomography of the Wrist.

Background: Previous studies have discussed the diagnostic value of four dimensional kinematic CT in cases of carpal instabilities. This analysis compares calculated skin doses of 4D CT and conventional cineradiography of the wrist in cases of suspected SLL rupture. Methods: Retrospective calculation and interpolation of skin doses and effective doses for ten consecutive 4D CT examinations and 41 cineradiographies for suspected lesions of the scapholunate ligament. Standardised anterior-posterior and lateral cine sequences using a flat-panel digital subtraction imager and of 4D kinematic CT using a dual-source scanner were acquired and acquisition parameters recorded. We tested if the skin dose of 4D CT is different from cineradiography. Results: Median dose area product (DAP) of cineradiography was 135.34 cGycm2 resulting in a calculated median skin dose of 32.6 mSv (confidence interval 26.86-42.90 mSv) and an estimated effective skin dose of 3.26 µSv. CT dose index (CTDI) for 4D examinations was recorded to be 26.79 mGy and the dose-length product (DLP) was 150 mGy × cm. This resulted in an estimated skin dose of 34 mSv, which is covered by the confidence interval of cineradiography, and an effective skin dose of 3.4 µSv. Conclusions: Skin dose calculations are comparable for 2D cineradiography in two plains and 4D kinematic CT of the wrist. Calculated effective doses are < 0.01 mSv.

ACTION trial: a prospective study on diagnostic Accuracy of 4D CT for diagnosing Instable ScaphOlunate DissociatioN.

BACKGROUND: Early detection of scapholunate ligament (SLL) tears is essential after minor and major trauma to the wrist. The differentiation between stable and instable injuries determines therapeutic measures which aim to prevent osteoarthritis. Arthroscopy has since been the diagnostic gold standard in suspected SLL tears because non-invasive methods have failed to exclude instable injuries reliably. This prospective study aims to determine the diagnostic accuracy of dynamic, 4D computed tomography (CT) of the wrist for diagnosing instable SLL tears. METHODS: Single center, prospective trial including 40 patients with suspected SLL tears scheduled for arthroscopy. Diagnostic accuracy of 4D CT will be tested against the reference standard arthroscopy. Radiologists will be blinded to the results of arthroscopy and hand surgeons to radiological reports. A historical cohort of 80 patients which was diagnosed using cineradiography before implementation of 4D CT at the study site will serve as a comparative group. DISCUSSION: Static imaging lacks the ability to detect instable SLL tears after wrist trauma. Dynamic methods such as cineradiography and dynamic magnetic resonance imaging (MRI) are complex and require specific technical infrastructure in specialized centers. Modern super-fast dual source CT scanners are gaining popularity and are being installed gradually in hospitals and ambulances. These scanners enable dynamic imaging in a quick and simple manner. Establishment of dynamic 4D CT of the wrist in patients with suspected SLL tears in in- and outpatient settings could improve early detection rates. Reliable identification of instable injuries through 4D CT scans might reduce the number of unnecessary diagnostic arthroscopies in the future. TRIAL REGISTRATION: This study was registered prospectively at the German Clinical Trials Register (DRKS) DRKS00021110 . Universal Trial Number (WHO-UTN): U1111-1249-7884.

What Is the Diagnostic Accuracy of Flat-panel Cone-beam CT Arthrography for Diagnosis of Scapholunate Ligament Tears?

BACKGROUND: Cone beam CT (CBCT) is a widely available technique with possible indications in carpal ligament injuries. The accuracy of CBCT arthrography in diagnosing traumatic tears of the scapholunate ligament has not been reported. QUESTIONS/PURPOSES: (1) What is the diagnostic accuracy of CBCT and how does it relate to the accuracy of multislice CT arthrography and conventional arthrography in diagnosing scapholunate ligament tears? (2) What is the estimated magnitude of skin radiation doses of each method? METHODS: This secondary analysis of a previous prospective study included 71 men and women with suspected scapholunate ligament tears and indications for arthroscopy. Preoperative imaging was conventional arthrography and either MSCT arthrography for the first half of patients to be included (n = 36) or flat-panel CBCT arthrography for the remaining patients (n = 35). Index tests identified therapy-relevant SLL tears with dorsal or complete SLL ruptures, and these tears were compared with relevant SLL tears which were determined through arthroscopy as Geissler Stadium III and IV by probing the instable SL joint with a microhook or arthroscope. These injuries were treated by open ligament repair and Kirschner wire fixation. Accuracy values and 95% confidence intervals were calculated. Additional estimates of the radiation skin doses of each CBCT exam and two MSCT protocols were subsequently calculated using dose area products, dose length products, and CT dose indices. RESULTS: The diagnostic accuracy was high for all imaging methods. 95% CIs were broadly overlapping and therefore did not indicate differences between the diagnostic groups: Sensitivity of CBCT arthrography was 100% (95% CI 77 to 100), specificity was 95% (95% CI 76 to 99.9), positive predictive value was 93% (95% CI 68 to 99.8), and negative predictive value was 100% (95% CI 83 to 100). For MSCT arthrography, the sensitivity was 92% (95% CI 64 to 99.8), specificity was 96% (95% CI 78 to 99.9), positive predictive value was 92% (95% CI 64 to 99.8), and negative predictive value was 96% (95% CI 78 to 99.9). For conventional arthrography, the sensitivity was comparably high: 96% (95% CI 81 to 99.9). Specificity was (81% [95% CI 67 to 92]); the positive predictive value was 77% (95% CI 59 to 89) and negative predictive value was 97% (95% CI 86 to 99.9). Estimated mean (range) radiation skin doses were reported in a descriptive fashion and were 12.9 mSv (4.5 to 24.9) for conventional arthrography, and 3.2 mSv (2.0 to 4.8) for CBCT arthrography. Estimated radiation skin doses were 0.2 mSv and 12 mSv for MSCT arthrography, depending on the protocol. CONCLUSION: Flat-panel CBCT arthrography can be recommended as an accurate technique to diagnose scapholunate ligament injuries after wrist trauma. Estimated skin doses are low for CBCT arthrography and adapted MSCT arthrography protocols. LEVEL OF EVIDENCE: Level III, diagnostic study.

Single versus dual Kirschner wires for closed reduction and intramedullary nailing of displaced fractures of the fifth metacarpal neck (1-2 KiWi): a randomized controlled trial.

AIMS: The aim of this study was to investigate whether clinical and radiological outcomes after intramedullary nailing of displaced fractures of the fifth metacarpal neck using a single thick Kirschner wire (K-wire) are noninferior to those of technically more demanding fixation with two thinner dual wires. PATIENTS AND METHODS: This was a multicentre, parallel group, randomized controlled noninferiority trial conducted at 12 tertiary trauma centres in Germany. A total of 290 patients with acute displaced fractures of the fifth metacarpal neck were randomized to either intramedullary single-wire (n = 146) or dual-wire fixation (n = 144). The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire six months after surgery, with a third of the minimal clinically important difference (MCID) used as the noninferiority threshold. Secondary outcomes were pain, health-related quality of life (EuroQol five-dimensional questionnaire (EQ-5D)), radiological measures, functional deficits, and complications. RESULTS: Overall, 151/290 of patients (52%) completed the six months of follow-up, leaving 83 patients in the single-wire group and 68 patients in the dual-wire group. In the modified intention-to-treat analysis set, mean DASH scores six months after surgery were 3.8 (sd 7.0) and 4.4 (sd 9.4), respectively. With multiple imputation (n = 288), mean DASH scores were estimated at 6.3 (sd 8.7) and 7.0 (sd 10.0). Upper (1 - 2α)) confidence limits consistently remained below the noninferiority margin of 3.0 points in the DASH instrument. While there was a statistically nonsignificant trend towards a higher rate of shortening and rotational malalignment in the single wire group, no statistically significant differences were observed across groups in any secondary outcome measure. CONCLUSION: A single thick K-wire is sufficient for intramedullary fixation of acute displaced subcapital fractures of the fifth metacarpal neck. The less technically demanding single-wire technique produces noninferior clinical and radiological outcomes compared with the dual-wire approach. Cite this article: Bone Joint J 2019;101-B:1263-1271.

Biomechanical comparison of the proximal interphalangeal joint arthrodesis using a compression wire.

INTRODUCTION/AIM: Arthrodesis of the proximal interphalangeal joint of the finger is a common procedure for the treatment of osteoarthritis. The aim of this biomechanical study was to compare the primary stability of one, respectively, two compression wires to intraosseous wiring and tension band wiring for the arthrodesis. MATERIALS AND METHODS: The stability of the arthrodesis was tested by applying flexion (n = 11) and extension (n = 10) force with 10° bending. Arthrodesis was achieved by one, respectively, two crossed compression wires and intraosseous wiring. In a control group (n = 11) tension band wiring was tested to 10° flexion and extension as well. RESULTS: Mean values for flexion bending for intraosseous wiring were 10.94 N, for one compression wire 12.82 N, for tension band wiring 17.95 N, and for two crossed compression wires 20.42 N. Mean values for extension bending were 9.71 N for intraosseous wiring, 13.63 N for one compression wire, 21.43 N for tension band wiring and 22.56 N for two crossed compression wires. CONCLUSION: The primary stability of the compression wires was statistically significant superior to intraosseous wiring. In comparison to tension band wiring which showed an intermediate stability. The application of a compression wire could be considered for further clinical testing in the arthrodesis of interphalangeal joints.

Ulnocarpal impaction syndrome: treatment with a transverse ulnar shortening osteotomy from an ulnodorsal approach.

INTRODUCTION: Ulnocarpal impaction syndrome is a common cause of chronic ulnar-sided wrist pain. The distal ulnar shortening osteotomy addresses the often present positive ulnar variance and therefore relieves the excessive load on the ulnocarpal joint. In the present study, the results of a technique that uses an ulnodorsal approach with a compression device and a transverse osteotomy are presented and compared to other techniques. MATERIALS AND METHODS: This retrospective study includes 92 wrists with an ulnocarpal impaction syndrome, which were treated with an ulnar shortening osteotomy. The mean duration of postoperative follow-up was 50 months. RESULTS: The mean ulnar variance was 2.17 ± 1.56 mm preoperatively and after the ulnar shortening osteotomy -1.36 ± 1.67 mm (p < 0.05). Radiological consolidation of the osteotomy could be shown in 91 wrists 6 months postoperatively. Patients rated the preoperative pain level at a VAS 7.9 ± 1.7 which decreased to a of VAS 2.4 ± 2.5 (p < 0.05). 19 patients complained of mechanical irritation. There was no neurological irritation. CONCLUSION: It could be shown that the distal ulnar shortening osteotomy by a transverse osteotomy using a compression device and an ulnodorsal approach has a low complication rate. It is comparable to the oblique osteotomy in effectiveness and safety.

Nodular giant cell tumour of the tendon sheath of the hand: analysis of eighty-four cases: diagnostic decisions and outcome.

INTRODUCTION: The giant cell tumour of the tendon sheath (GCTTS) of the hand is a benign tumour of unknown origin. The clinical diagnosis is supported by preoperative imaging. But the ideal imaging methods necessary for the diagnosis, preoperative planning and total tumour resection are still debated. Standard treatment is surgical resection with histological confirmation. METHODS: We followed up 84 patients who were operated upon for a histologically confirmed nodular type GCTTS for an average of 4.7 years (range four to eight). The preoperative symptoms and radiological findings of X-ray, ultrasound and MRI were reviewed and the surgeon asked for their impact on the surgical procedure. RESULTS: The average age at operation was 50.9 years, 65.5% of the patients were female and 61.9% of the lesions were located on the palmar aspect. Most tumours were found on the first three fingers. Two patients had tumours at two separate sites (2.4%). After an average follow up of 31.5 months two recurrences were observed (2.4%). In addition to X-ray and ultrasound, the preoperative findings of the MRI had no influence on the surgical procedure. CONCLUSION: Our data on the nodular GCTTS are in accordance with published data concerning the age distribution, gender distribution, and localisation. No soft-tissue imaging method is superior for the diagnosis of nodular GCTTS or for the preoperative planning. A preoperative MRI may not be necessary as clinical and ultrasound examination are sufficient. To exclude bony erosions, a preoperative X-ray is necessary.

Postoperative monitoring of free vascularized bone grafts in reconstruction of bone defects.

Vascularized bone transfer is increasingly recognized as a very useful and versatile technique for reconstructing large bone defects. It is especially indicated in patients with challenging conditions, such as nonunions, postoncologic resections, severe trauma, and congenital defects. With increasing experience of reconstructive surgeons, improved microsurgical techniques, and more enhanced flaps, the failure rate of free flaps has been reduced in the last decades. Especially, the early-postoperative period is decisive in the outcome of surgery. Several techniques have been described for monitoring the postoperative viability of microsurgical free vascularized graft, and their sensitivity and reliability continues to be the object of animal experiments and clinical trials. The qualities of an optimal monitoring device should be objective, continuous, noninvasive, safe, reproducible, easily managed, and interpretable for the nursing staff, inexpensive, and a clear indicator of changes in arterial and venous circulation. Presently, no one neither fulfills all of the criteria completely nor is uniformly accepted. In this article, relative advantages and disadvantages of these various postoperative monitoring techniques are discussed.

Minimally invasive spinal surgery using nucleoplasty: a 1-year follow-up study.

BACKGROUND: Nucleoplasty is a minimally invasive percutaneous intradiscal coblation therapy option in patients with chronic discogenic low back pain. The purpose of this prospective study was to assess the effectiveness of nucleoplasty in our patients up to 1 year after treatment. METHOD: All patients included in this study suffered from established back pain and/or radiating pain in the lower extremities. Age, gender, weight, body mass index (BMI) and smoking status were recorded and the clinical status of the patient documented using a visual analogue pain scale (VAS). Additionally, patients were asked to provide details regarding analgesic consumption, disability and ability to work. Nucleoplasty was carried out under fluoroscopic and CT-guidance. All treated patients were reviewed at 6 and 12 months. FINDINGS: Between April 2005 and December 2006, 96 patients underwent nucleoplasty in our department. The 69 patients reported here were followed-up to 12 months while data for eight others is available only up to 6 months. Seven patients were lost to follow-up, while eleven were excluded due to a secondary disc sequestration, either at the treated segment or elsewhere. The mean age of the 27 females (39%) and 42 males in this study was 42 years (range 18-74). The mean duration of symptoms was 30.5 months (range 1-120). Forty-two percent of patients were smokers and the mean BMI was 26.3 (17.4-42.4). 73% of treated patients experienced an improvement of more than 50% in their symptoms in the early post-operative VAS score. This was reduced to 61% at 6 months post-operatively and 58% after 1 year. A statistically significant reduction in analgesic consumption, disability and occupational incapacitation resulted from treatment with nucleoplasty. CONCLUSIONS: Nucleoplasty is an effective therapy for chronic, discogenic back pain which results in significant reductions in levels of disability and incapacity for work as well as decreased analgesic consumption.

Diagnostic accuracy of plain radiographs and cineradiography in diagnosing traumatic scapholunate dissociation.

OBJECTIVE: Missed tears of the scapholunate ligament (SLL) and scapholunate dissociation (SLD) after wrist injuries pose a high risk of post-traumatic osteoarthritis of the carpus. Plain X-rays and dynamic radiographic studies are frequently used for initial diagnostic work-up. Given the limited evidence of their accuracy, we retrospectively compared the radiographic findings of patients with suspected traumatic SLD with wrist arthroscopy as the accepted reference standard. DESIGN AND METHODS: During a 6-year period, plain radiographs and DSA cineradiography scans were obtained from 198 patients who had sustained a hyperextension injury to their hand. Of those, 102 (72 men, 30 women, mean age of 42+/-12 years) subsequently underwent diagnostic arthroscopy. Digital images were reevaluated by experienced radiologists unaware of the arthroscopic findings for the presence or absence of SLD. We calculated the sensitivity (SN) and specificity (SP) with 95% confidence intervals (CI), and computed areas under the receiver operating characteristic curves (AUC/ROC). RESULTS: Arthroscopy revealed 42 SLL ruptures, 13, 10, and 19 of which were classified as grade I (partial), II (complete with dynamic instability), or III (complete with static instability) respectively. Plain radiographs correctly identified 24 injuries (SN 57.1%, 95% CI 41.0-72.3%), and produced 1 false-positive result (SP 98.3%, 95% CI 91.1-100.0%). The scapholunate distance and the SL angle contributed independently to the diagnostic variance, with an AUC/ROC of 85.7% (95% CI 76.8-92.2%). Cineradiography had a sensitivity of 36 out of 42 (85.7%, 95% CI 71.5-94.6%), and a specificity of 57 out of 60 (95.0%, 95% CI 86.1-99.0%). CONCLUSION: Pathological results on plain radiographs and cineradiography reliably indicate the presence of SLD after wrist trauma. Although non-conclusive, a negative dynamic study markedly reduces the pre-test probability of disease. Both methods remain key elements of primary diagnostic strategies for suspected traumatic SLD, and may facilitate the selection of additional tests.

Reconstruction of large defects of the long bones with free vascularized bone grafts: functional results after minimum 5-year follow-up.

This study evaluated the clinical and radiographic results of 44 patients (26 men and 18 women) who underwent reconstruction of large defects of the long bones with free vascularized bone grafts. Mean patient age was 29+/-15 years and mean follow-up was 8.6+/-2.1 years. Mean Enneking index was 78.6% (95% confidence interval, 73.8-83.4). No differences were noted for different types of graft, etiologies, or anatomic locations. Regression analysis revealed no association between defect size and functional results. Sixteen patients developed 29 complications. All but 1 patient showed full incorporation of the graft. These results confirm the value of vascularized grafts for bridging large bone defects.

Does chemotherapy impair the bone healing and biomechanical stability of vascularized rib and fibula grafts?

The purpose of this study was to observe the impact of chemotherapy on the healing and biomechanical properties of vascularized bone grafts. Ten male beagle dogs were divided into two experimental groups: a chemotherapy group (CH) and control group (C). Group CH received adjuvant and neo-adjuvant chemotherapy. Each animal of both groups underwent the following operative procedures. The 5th and 7th rib were removed and replaced by vascularized pedicle transfers of the adjacent 4th and 8th rib. Additionally, a free fibular flap was elevated and retransferred to the same anatomic position. The rate of bony union on plain x-ray was 100 percent in group C, 30 percent in the vascularized rib, and 80 percent in the fibula grafts of group CH. Microangiography demonstrated no avascular bone segments in group C and in the fibula flaps of group CH. The vascularized ribs of group CH presented with 20 percent avascular bone segments. Biomechanical tests focusing on the durability of the vascularized grafts against bending and torsion forces demonstrated a reduction of the average maximum bending times by 17 percent and 23.9 percent compared to the controls ( P < 0.05). The twisting times were reduced by 13.8 percent (n.s.) and 32.5 percent ( P < 0.05). The data demonstrated a clear worsening in bone healing and stability after simulated adjuvant and neo-adjuvant chemotherapy. Thus, a large animal model was established for the further determination of the effects of chemotherapy on different vascularized bone transfers.

The application of vestibular-evoked myogenic potentials in otoneurosurgery.

OBJECTIVE: To evaluate the applicability of vestibular-evoked myogenic potentials (VEMPs) in the diagnostics, intraoperative monitoring, and postoperative follow-up of patients in otoneurosurgery. STUDY DESIGN: A prospective study of patients who underwent either cochlear implantation (CI, n = 18) or were diagnosed with an acoustic neuroma (AN, n = 9) or with neuro(micro)vascular compression of the VIIIth nerve (NVC, n = 27) in the period 2002 to 2004. The follow-up was 1 year for all patients. SETTING: A tertiary-referral unit. RESULTS: VEMPs could be recorded in 64% of all patients before CI and in 22% after surgery. The patients with AN had normal VEMPs in 22% of all cases when first diagnosed. Normal VEMPs were found in 37% of those patients with NVC. From the 5 AN patients who had to be operated, only 1 had intact VEMPs after surgery. In contrast, after microvascular decompression all patients (4) had normal VEMPs. CONCLUSIONS: VEMPs are helpful in diagnosing patients with vertigo to better identify saccular defects. They are highly sensitive in the early diagnosis of retrocochlear lesions. SIGNIFICANCE: VEMPs can help to reliably identify patients with a retrocochlerar lesion at an early stage and can be used in intraoperative, neurophysiological monitoring. EBM RATING: C-4.

Impact of radiation therapy on healing and stability of vascularized bone grafts in a dog model.

The purpose of the study was to observe the impact of radiation therapy on healing and biomechanical properties of vascularized bone grafts, and thus to establish an appropriate large animal model. Ten male beagles were divided into two experimental groups: radiation (R) and control (C). The left 5th to 7th ribs of the animals of group R were irradiated 3 and 2 weeks preoperatively, using a dose of 8 Gy each time. Each animal of both groups underwent the following operative procedures. The 5th and 7th ribs were removed, and the 5th rib was replaced by a vascularized pedicle transfer of the 4th rib. The 7th rib was reconstructed using a pedicle transplant of the 8th rib. The 5th and 7th ribs were used as nonvascularized bone grafts to replace the donor sites of the 4th and 8th ribs, respectively. Group R received two further irradiation cycles 2 and 3 weeks postoperatively. The vascularized rib grafts of group R demonstrated a higher number of delayed unions in plain x-rays and avascular bone segments in microangiography than the control group. The presence of vital osteocytes in histology was not significantly different between groups. Biomechanical tests focusing on the durability of vascularized ribs against bending and torsion forces demonstrated a reduction of average maximum bending moments by 56.6% after radiation compared to controls (P < 0.05). Twisting moments were reduced by 47.6% (P < 0.05). The data demonstrate a significant worsening in bone healing and stability after pre- and postoperative radiation therapy to the wound bed and bone grafts. Thus, a large animal model is established for further determination of different strategies of radiotherapy in combination with vascularized bone transfers.

The "pull-back" technique for Nucleus 24 perimodiolar electrode insertion.

OBJECTIVE: To observe the influence of electrode pull-back after cochlear implant insertion of Nucleus 24 perimodiolar electrodes. STUDY DESIGN: In a prospective intraoperative study, we analyzed the impedances, neural response telemetry responses, and the spread of excitation after cochlear implant electrode insertion and compared these data to those obtained after a subsequent, controlled pull-back of the electrode. Postoperative depth of electrode insertion was controlled by x-ray. SETTING: Tertiary referral center. SUBJECTS: Six patients (4 male, 2 female; 18 to 69 years) were implanted with a Nucleus 24 (RCA) cochlear implant with a perimodiolar electrode. RESULTS: After a controlled pull-back, a significant decrease of the spread of excitation at the stimuli electrodes 5, 10, 15, and a nonsignificant decrease at stimuli electrode 20 compared to the recordings after the primary normal insertion procedure was found. The mean electric compound action potential amplitude was increased with an apical-to-basal tendency. Impedances remained unchanged by the pull-back. Mean insertion depth at the postoperative x-ray control was 372 degrees (+/- 10.2). CONCLUSION: Controlled cochlear implant electrode pull-back is a novel technique that optimizes objective intraoperative electrophysiological recordings in patients implanted with a Nucleus 24 perimodiolar cochlear implant by a greater approximation of the electrode to the modiolus.