Perforation Of Cortex Research Articles

Inferior Suture Anchor Placement During Arthroscopic Bankart Repair

Background: During arthroscopic Bankart repair, inferior anchor placement is critical to a successful outcome. Low anterior anchors may be placed with a standard straight guide via midglenoid portal, with a straight guide with trans-subscapularis placement, or with curved guide systems. Purpose/Hypothesis: To evaluate glenoid suture anchor trajectory, position, and biomechanical performance as a function of portal location and insertion technique. It is hypothesized that a trans-subscapularis portal or curved guide will improve anchor position, decrease risk of opposite cortex breach, and confer improved biomechanical properties. Study Design: Controlled laboratory study. Methods: Thirty cadaveric shoulders were randomized to 1 of 3 groups: straight guide, midglenoid portal (MG); straight guide, trans-subscapularis portal (TS); and curved guide, midglenoid portal (CG). Three BioRaptor PK 2.3-mm anchors were inserted arthroscopically, with an anchor placed at 3, 5, and 7 o’clock. Specimens were dissected with any anchor perforation of the opposite cortex noted. An “en face” image was used to evaluate actual anchor position on a clockface scale. Each suture anchor underwent cyclic loading (10-60 N, 250 cycles), followed by a load-to-failure test (12.5 mm/s). Fisher exact test and mixed effects regression modeling were used to compare outcomes among groups. Results: Anchor placement deviated from the desired position by 9.9° ± 11.4° in MG specimens, 11.1° ± 13.8° in TS, and 13.1° ± 14.5° in CG. After dissection, opposite cortex perforation at 5 o’clock occurred in 50% of MG anchors, 0% of TS, and 40% of CG. Of the 90 anchors tested, 17 (19%) failed during cyclic loading, with a similar failure rate across groups (P = .816). The maximum load was significantly higher for the 3-o’clock anchors when compared with the 5-o’clock anchors, regardless of portal or guide (P = .021). For the 5-o’clock position, there were significantly fewer “out” anchors in the TS group versus the CG or MG group (P = .038). There was no statistically significant difference in maximum load among groups at 5 o’clock. Conclusion: Accuracy in suture anchor placement during arthroscopic Bankart repair can vary depending on both portal used and desired position of anchor. The results of the current study indicate that there was no difference in ultimate load to failure among anchors inserted via a midglenoid straight guide, midglenoid curved guide, or percutaneous trans-subscapularis approach. However, midglenoid portal anchors drilled with a straight or curved guide and placed at the 5-o’clock position had significant increased risk of opposite cortex perforation compared with trans-subscapularis percutaneous insertion, with no apparent biomechanical detriment. Clinical Relevance: The findings from this study will facilitate improved understanding of risks and benefits of several techniques for arthroscopic shoulder instability treatment with regard to suture anchor fixation.

Impaction Grafting in Revision Total Elbow Arthroplasty Due to Aseptic Loosening and Bone Loss

With the increase in the number of total elbow arthroplasties being performed, there has been a parallel increase in revision surgery. There is limited information about the outcome of impaction grafting following failed elbow arthroplasty. We retrospectively analyzed sixteen cases of revision arthroplasty performed following aseptic loosening of a semiconstrained total elbow replacement. There were three men and thirteen women with a mean age of 58.4 years (range, twenty-eight to seventy-five years). Fourteen elbows had loosening of both the humeral and the ulnar component, and two elbows had only humeral loosening. Two elbows had perforation of the humeral cortex by the humeral component, and one had perforation of the ulnar cortex. Grade-II bone loss as described by King et al. was found in three elbows; grade III, in six elbows; and grade IV, in seven elbows. The impaction grafting was performed with only allograft in thirteen elbows, and it was done with allograft as well as autograft from the iliac crest in the other three elbows. The mean duration of follow-up was 7.4 years (range, 4.1 to 11.2 years). The mean Mayo Elbow Performance Score (MEPS) for pain significantly improved from 15.0 points preoperatively to 32.8 points at the time of latest follow-up (p = 0.003). The mean arc of flexion also significantly increased, from 60.3° to 115.6° (p < 0.01). Stability according to the MEPS significantly increased from a mean of 2.2 points to a mean of 9.4 points (p = 0.001). The mean total MEPS improved from 41.0 points to 82.8 points (p = 0.001). The result was excellent for four elbows, good for eleven, and fair for one. Follow-up radiographs demonstrated fifteen cases with grade-I resorption of the bone graft and one case with grade-II resorption. A type-I radiolucent line was observed in twelve of the elbows; type II, in three; and type IV, in one. Additional surgery was required in two cases. Impaction grafting is an effective technique when revision total elbow arthroplasty is used for the treatment of aseptic loosening with bone loss. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A multi-level rapid prototyping drill guide template reduces the perforation risk of pedicle screw placement in the lumbar and sacral spine

The method of free-hand pedicle screw placement is generally safe although it carries potential risks. For this reason, several highly accurate computer-assisted systems were developed and are currently on the market. However, these devices have certain disadvantages. We have developed a method of pedicle screw placement in the lumbar and sacral region using a multi-level drill guide template, created with the rapid prototyping technology and have validated it in a clinical study. The aim of the study was to manufacture and evaluate the accuracy of a multi-level drill guide template for lumbar and first sacral pedicle screw placement and to compare it with the free-hand technique under fluoroscopy supervision. In 2011 and 2012, a randomized clinical trial was performed on 20 patients. 54 screws were implanted in the trial group using templates and 54 in the control group using the fluoroscopy-supervised free-hand technique. Furthermore, applicability for the first sacral level was tested. Preoperative CT-scans were taken and templates were designed using the selective laser sintering method. Postoperative evaluation and statistical analysis of pedicle violation, displacement, screw length and deviation were performed for both groups. The incidence of cortex perforation was significantly reduced in the template group; likewise, the deviation and displacement level of screws in the sagittal plane. In both groups there was no significantly important difference in deviation and displacement level in the transversal plane as not in pedicle screw length. The results for the first sacral level resembled the main investigated group. The method significantly lowers the incidence of cortex perforation and is therefore potentially applicable in clinical practice, especially in some selected cases. The applied method, however, carries a potential for errors during manufacturing and practical usage and therefore still requires further improvements.

Revision total hip replacement with a cemented long femoral component: minimum 9-year follow-up results

Surgical revision after failed total hip replacement is a technically challenging procedure. The aim of this study was to analyze the long-term results of revision total hip replacement using a cemented long femoral component and identify factors that influence the results. We retrospectively reviewed 34 hips in 33 patients who had undergone revision total hip replacement using a cemented long femoral component between 1994 and 2001. Hip function was evaluated according to the scoring system of the Japanese Orthopaedic Association. Radiographic examination was performed for evaluation of stem loosening, and its possible risk factors were investigated. The mean follow-up duration was 11.3 years (9-15). Perioperative complications included intraoperative femoral cortex perforation (six hips, 18 %), dislocation (five hips, 15 %), deep venous thrombosis (one hip, 3 %) and postoperative periprosthetic fracture (one hip, 3 %). The mean preoperative Japanese Orthopaedic Association hip score was 50.3 ± 14.9 vs 78.2 ± 11.5 at the latest follow-up. The Kaplan-Meier survival rate at 15 years, calculated using radiological failure or re-revision of the femoral component for any reason as the end point, was 87 or 100 %, respectively. The failure-free survival rate for the subgroup with a good-quality cement mantle was significantly higher than that for the subgroup with poor quality (p = 0.033). The quality of cementation was identified as a significant risk factor for further loosening. Revision total hip replacement using a cemented long femoral component yielded satisfactory long-term results in this series.

Inferior Anchor Cortical Perforation With Arthroscopic Bankart Repair: A Cadaveric Study

The aims of this study were to evaluate the incidence of anchor penetration of the far cortex of the glenoid neck after arthroscopic Bankart repair and to compare the biomechanical properties of anchors in the 4- and 5:30- to 6-o'clock positions on the glenoid. Twelve (6 matched pairs) fresh-frozen human cadaveric shoulders were used to simulate arthroscopic Bankart repair in the lateral decubitus position. The most inferior anchor (5:30 to 6 o'clock) and that above it (4 o'clock) were inserted via the anteroinferior portal on the glenoid using the standard technique. After both anchor insertions, anchor perforation of the glenoid far cortex was identified. Biomechanical properties were measured to determine cyclic displacement of anchors at 100 and 500 cycles, stiffness, yield load, and ultimate failure strength. All 12 suture anchors (100%) at 5:30 to 6 o'clock penetrated throughout the far cortex, whereas only 4 anchors (33%) at 4 o'clock did so (P = .005). The mean distance the anchor tip traveled into far cortex was significantly longer at 5:30 to 6 o'clock than at 4 o'clock (6.8 ± 1.6 mm v 2.0 ± 1.6 mm, P = .001). In terms of mechanical strength, anchors at 5:30 to 6 o'clock had greater 100- and 500-cycle mean displacements than those at 4 o'clock (3.0 ± 0.5 mm v 2.5 ± 0.3 mm, P = .018 for 100 cycles; 3.5 ± 0.7 mm v 2.8 ± 0.3 mm, P = .018 for 500 cycles), although no differences in ultimate failure strength after cyclic loading were found between 2 positions (133.4 ± 40.3 and 133.7 ± 29.2 N, respectively; P = .985). For arthroscopic Bankart repair, insertion of the most inferior anchor via the anteroinferior portal with standard technique, in the lateral decubitus position, carries a high risk of perforating the inferior far cortex of the glenoid (100% in our study). This may result in mechanical weakness of the most inferior repair specifically in the early postoperative period. Perforation of the glenoid far cortex by the most inferior anchor and its mechanical weakness should be taken into consideration. Further study is needed to improve surgical technique to place the most inferior anchor in an optimal position by arthroscopy.

Anaesthesia and common oral and maxillo-facial emergencies

Odontogenicor dental-related infections begin with decay and progress to pulpitis, which is inflammation of the nerve chamber in the centre of the tooth. Infection then spreads into the bone and causes perforation of the bone cortex into the subperiosteal region. Fascial planes of the head and neck are virtual spaces, bounded by muscle attachments and bone. The muscle attachments and fascial planes will govern in which direction the infection spreads to the soft tissue spaces. Knowledge of the orofacial musculature is needed to predict the path of infection. The commonly affected fascial spaces are illustrated in Figures 1 and 2. Infection can spread from these into the infra-temporal fossa, sub-temporalis, and parapharyngeal spaces. This describes the local or direct spread. The spread from the pre-maxillary region (soft tissue anterior to the maxilla containing the canine and part of the buccal space) can progress to orbital cellulitis. If left unchecked, this can lead to cavernous sinus thrombosis. A parapharyngeal abscess often has little clinical signs until the airway is compromised, as the swelling is intra-oral or parapharyngeal. A frequent culprit is a wisdom tooth which also causes submasseteric inflammation and trismus. Examination of the pharynx is almost impossible in the presence of severe trismus and patients are often falsely downgraded in priority, due to lack of visible swelling. Complications of spread to cervical fascial planes include airway obstruction, mediastinitis, and pulmonary aspiration of pus either through spontaneous rupture or iatrogenic rupture during attempts at intubation. The haematogenous spread can lead to thrombophlebitis, bacteraemia, prosthetic valve, or joint involvement and systemic sepsis. The spread of infection is affected by compromised host defences such as diabetes mellitus, malignancy, or immunosuppression.

Use of Simple Algorithms to Predict Screw Length Facilitates Navigation-controlled Medial Opening-wedge Osteotomy Using the TomoFix HTO System

This study was performed to establish simple algorithms to predict proper screw lengths for the 4 proximal holes of TomoFix plates (Synthes GmbH; Solothurn, Switzerland) based on radiographic mediolateral (ML) and anteroposterior (AP) dimensions of the proximal tibia and to determine how well these algorithms function for navigation-controlled medial opening-wedge high tibial osteotomy (HTO) using TomoFix. Experimental HTO surgery was performed in proximal tibial models manufactured for 30 patients undergoing HTO to determine the longest screw lengths for the 4 proximal holes of TomoFix plates. Eight algorithms were created for the 4 proximal screws by investigating the relationships between measured screw lengths and radiographic dimensions and were used for 30 navigation-controlled medial opening-wedge HTOs. The algorithms used to predict screw length were: screw A=ML width-20 mm and AP length+5 mm; screw B=ML width-25 mm and AP length; screw C=ML width-35 mm and AP length-10 mm; and screw D=ML width-40 mm and AP length-15 mm. All 30 surgeries were performed with no perioperative adverse events. Mean operative time was 47.1 minutes, and no far cortex perforation of more than 3 mm was observed for any of the 4 proximal screws. Mean mechanical tibiofemoral angle and weight load line coordinate at the knee joint were valgus 3.7° and 62.9%, respectively. Targeted alignment was achieved in 28 (93%) knees for a mechanical tibiofemoral angle between valgus 2° and 6°, and in 25 (83%) knees for a weight load line coordinate between 55% and 70%. The authors propose the use of the developed algorithms to select proper screw lengths for medial opening wedge HTO using the TomoFix HTO system.

Total shoulder arthroplasty does not correct the orientation of the eroded glenoid

Background and purpose Alignment of the glenoid component with the scapula during total shoulder arthroplasty (TSA) is challenging due to glenoid erosion and lack of both bone stock and guiding landmarks. We determined the extent to which the implant position is governed by the preoperative erosion of the glenoid. Also, we investigated whether excessive erosion of the glenoid is associated with perforation of the glenoid vault.Methods We used preoperative and postoperative CT scans of 29 TSAs to assess version, inclination, rotation, and offset of the glenoid relative to the scapula plane. The position of the implant keel within the glenoid vault was classified into three types: centrally positioned, component touching vault cortex, and perforation of the cortex.Results Preoperative glenoid erosion was statistically significantly linked to the postoperative placement of the implant regarding all position parameters. Retroversion of the eroded glenoid was on average 10° (SD10) and retroversion of the implant after surgery was 7° (SD11). The implant keel was centered within the vault in 7 of 29 patients and the glenoid vault was perforated in 5 patients. Anterior cortex perforation was most frequent and was associated with severe preoperative posterior erosion, causing implant retroversion.Interpretation The position of the glenoid component reflected the preoperative erosion and “correction” was not a characteristic of the reconstructive surgery. Severe erosion appears to be linked to vault perforation. If malalignment and perforation are associated with loosening, our results suggest reorientation of the implant relative to the eroded surface.

Accidental Perforation of the Lateral Femoral Cortex in ACL Reconstruction: An Investigation of Mechanical Properties of Different Fixation Techniques

The aim of this study was to evaluate the mechanical properties of anterior cruciate ligament (ACL) reconstruction using the medial portal technique with cortical fixation and hybrid fixation after penetration of the lateral cortex by use of different drill sizes. In this biomechanical study a porcine in vitro model was used. The testing protocol consisted of a cyclic loading protocol (1,000 cycles, 50 and 250 N) and subsequent ultimate failure testing. Number of cyclic loadings survived, stiffness, yield load, maximum load, and graft elongation, as well as failure mode, were analyzed after ACL reconstruction with 5- to 9-mm soft-tissue grafts. In the control group, conventional penetration of the lateral cortex with a 4.5-mm drill and cortical fixation were performed. In the tested groups, the lateral cortex was penetrated with a drill matching the graft size. In the first part of the study, we used cortical fixation. In the second part, we used hybrid fixation with an interference screw. In the first part of the study, ACL reconstruction with 5- to 6-mm perforation of the lateral cortex showed no significant differences in ultimate failure load after cyclic loading compared with the control group (P > .05). Specimens with reconstruction with 7- to 9-mm perforation of the lateral cortex and cortical fixation did not survive the cyclic loading protocol. In the second part of the study, with a hybrid fixation technique, ultimate failure testing after cyclic loading of specimens with 7- to 9-mm penetration showed no significant differences in tested parameters compared with the control group (P > .05). After penetration of the lateral cortex with a drill size of more than 6 mm, cortical ACL fixation results in poor mechanical properties. Hybrid fixation increases the mechanical properties significantly after penetration with a 7- to 9-mm drill. We advise caution to avoid penetration of the lateral femoral cortex when using cortical flip-button fixation. In case of accidental perforation of the lateral cortex with a diameter greater than 6 mm, we recommend performing hybrid fixation.

Factors associated with hematoma of the floor of the mouth after placement of dental implants

The aim of this article is to determine factors associated with hematoma during placement of dental implants in the anterior mandible and to provide the dental practitioner with preventive measures to avoid such a life-threatening complication. All available clinical case studies from (1986 to 2010) published in English or with English abstract were reviewed and analyzed. Nineteen studies have been identified and written in the literature. Most of the reported studies were case series and they showed that hematoma is a very rare complication, but general dental practitioners do not pay attention to the significance of the mandible anatomy in the anterior area and the possibility of perforation of the lingual cortex during placement of the dental implants in that position. The use of dental CT in planning the implant treatment coupled with accurate determination of implant length in order to provide detailed data about the mandible anatomy are highly recommended to avoid the occurrence of hematoma in the floor of the mouth and the airway obstruction that may lead to death during placement of dental implants in the anterior mandible.

Paper # 189: Pitfall in ACL Reconstruction Using a Medial Portal Approach: Penetration of the Second Femoral Cortex

Paper # 189: Pitfall in ACL Reconstruction Using a Medial Portal Approach: Penetration of the Second Femoral Cortex

Minimally Invasive Fluoro-Navigation Screw Fixation for the Treatment of Pelvic Ring Injuries

Intensive use of intraoperative fluoroscopy is mandatory to achieve good accuracy and avoid neural or vascular injury and may prolong surgical time and increase exposure-related hazards. New methods of percutaneous treatment in conjunction with innovative fluoroscopy-based computerized navigation have evolved in an attempt to overcome the existing difficulties. This report described our experience in applying fluoroscopic surgical navigation technique and evaluated its clinical application to pelvic ring injuries, including its feasibility, merits and limitations. Twenty-two patients with pelvic ring injuries were treated with percutaneous pubic ramus screw and sacroiliac screw techniques under the guidance of a fluoroscopy-based navigation system. A total of forty-four screws were inserted, including twenty-seven pubic ramus screws and seventeen sacroiliac screws. The average operation time and the average fluoroscopy time per screw were 23.6 minutes and 22.2 seconds respectively. Compared to the final position of the screw, the average deviated distance of wire tip was 2.8 mm and the average trajectory difference was 2.6°. A ventral cortex perforation of the sacrum was found in one sacroiliac screw without any clinical symptoms. No superficial or deep infection occurred. No patient sustained recognized neurologic, vascular, or urologic injury as a result of percutaneous screw fixation of pubic ramus fractures, sacroiliac disruptions, or sacral fractures. Our results showed that fluoroscopy-based navigation technique for the pelvic ring injuries could become a safe and effective alterative method for the treatment of pelvic ring injuries in some selected patients.

Tactile Feedback Comparison of Manual, Hammer, and Rotary Powered Needle Insertion Accuracy for Bone Marrow Biopsy and Other Procedures

AbstractAbstract 4752 Introduction:For decades, clinicians have performed bone marrow sampling procedures by manually twisting and pushing auger-like devices into bones, with variable and less than ideal results. For the clinician, the bone marrow biopsy is generally a blind procedure during needle advancement without any dynamic visual reference, except the external view of the patient and the device. The clinician is required to feel the tissue levels, including bone of widely diverse densities, communicated via the needle to the hand. The procedure is relatively straightforward but substantial skill and experience are required by the operator to complete the procedure quickly, safely and effectively, with minimal pain to the patient. With the introduction of rotary power to access the intraosseous space, the question of needle tip control has been open to debate. Some clinicians question whether the ease of insertion with a rotary-powered device would lead to perforation of the opposite cortex of the bone and/or damage adjacent tissues. Objectives:The investigators sought to study the relative precision of anatomical placement of the needle tip in bones using only tactile feedback. The objective was to determine if clinicians were able to correctly place the needle tip into a specific target area of simulated bone more often and in less time when using rotary powered intraosseous devices than when using manually inserted devices, or hammer-assisted insertion devices, when relying primarily on tactile feedback to determine correct depth of penetration. Better tactile feedback with the rotary power would allow clinicians to accurately predict the level of control over needle placement. Additionally, needles inserted with rotary power would cause less damage to simulated bone than those inserted with manual or hammer-assisted techniques. Methods:Three different FDA-cleared 11 gauge stainless steel needle types were compared in a randomized prospective study test blocks of artificial bone. The needle types were Manual inserted (Manual), Hammer-assisted (Hammer), and Rotary-powered inserted (Power). Test blocks were specifically designed of three different thicknesses each simulating the characteristics of human bone. Eleven clinicians participated in the study. Following each insertion, the participant was asked to rate his/her confidence level of insertion accuracy on a scale of 0 to 10. Position of the needle tip was assessed by fluoroscopic confirmation. Each participant also inserted each needle type into a simulated osteoporotic bone model (raw chicken egg). The ability to insert the needle into the osteoporotic model without damage was based on visual assessment. Data were analyzed using SPSS for Windows. Results:Each of the 11 participants used each of the three needle types (Manual, Hammer, and Power) on each of the three different simulated bone types, for a total of 9 insertions each. Total number of insertions for the study was 99 (9×11). Mean insertion times were Manual: 20.7 ± 10.1 seconds, Hammer: 12.7 ± 5.9 seconds, and Power: 8.7 ± 2.8 seconds. Differences were statistically significant (p<0.001). Insertion success by devices, defined as correct placement of the needle tip to a specific target depth, was Manual: 48.5%, Hammer: 69.7%, Power: 97.0%. Differences were statistically significant (p<0.001). On a scale of 0 to 10, mean insertion certainty levels, defined as the clinicians perception of needle tip placement into the correct location, by devices were Manual: 48% certainty, Hammer: 61% certainty, and Power: 91% certainty. All certainty comparisons between devices were statistically significant (p<0.05). Using a raw egg to simulate osteoporotic bone, insertion rates without damage were Manual: 19.2%, Hammer: 36.4%, and Power: 100%. Differences were statistically significant (p<0.001). Conclusions:Correct placement of a bone biopsy needle into a precise target area using tactile feedback only was markedly better and faster when using a rotary powered needle than when using a Manually inserted or a Hammer assisted device. The operator's impression of correct needle placement correlated with actual control of needle placement. Damage to fragile bone models was negligible with the Powered device compared to marked damage from the Manual and Hammer devices. These findings may have far reaching clinical applications when determining the best method for performing bone marrow biopsies. Disclosures:Miller:Vidacare Corporation: Employment, Equity Ownership, Patents & Royalties. Bolleter:Vidacare Corporation: Consultancy, Employment, Equity Ownership, Patents & Royalties. Philbeck:Vidacare Corporation: Employment. Montez:Vidacare Corporation: Employment.

Minimally Invasive Fixation of Displaced Midclavicular Fractures With Titanium Elastic Nails

Clavicular fractures account for 2.6% of all fractures, and more than 80% involve the middle third of the clavicle. Plate fixation has been the most common method of fixation reported but has been associated with complications such as infection, wound breakdown, nonunion, implant failures, poor cosmetic outcome, and local skin numbness. We report on a series of cases receiving minimally invasive insertion of titanium elastic nails (TEN) to fix the displaced midclavicular fractures. Prospective, clinical study. Regional referral center. From November 2006 to October 2007, we operated on 23 patients (16 men) with displaced (no cortical contact between the proximal and distal fragments radiographically and/or greater than 2 cm of shortening) midclavicular fractures fixed with TEN. The mean age of the patients was 41.57 years. All patients with displaced midclavicular fractures were treated with TEN. The nails were inserted from the medial entry point on the sternal end and passed through the fracture site under fluoroscopy monitoring. Complications, clavicular shortening after TEN fixation, Constant shoulder score, and Disability of the Arm, Shoulder, and Hand score for functional outcome measurement. Closed reduction was successful in 16 patients, and seven patients needed open reduction. There was no nonunion, infection, nail breakage, or refracture after nail removal in our series. The mean operative wound length was 2.2 cm, and mean clavicular length shortening was 0.32 cm. Iatrogenic perforation of the lateral cortex occurred in two patients, and nail misplacement occurred in one patient requiring revision. All patients followed up greater than 12 months. The mean Disability of the Arm, Shoulder, and Hand score was 6 (range, 0-35; standard deviation, 10.47) and mean Constant score was 96 (range, 78-100; standard deviation, 6.34). Minimally invasive fixation with TEN is a safe method and can be performed with minor complications. This method of fixation of displaced midclaviclular fractures should result in a good cosmetic appearance and satisfactory stabilization of displaced midclavicular fractures without comminution.

A-Mode ultrasound guidance for pedicle screw advancement in ovine vertebral bodies

Background context In pedicle screw fixation surgery, rigid instruments are inserted into a vertebral body. When the instruments are misdirected within the pedicle or advanced too far beyond it, perforations of the inner or outer cortex can cause damage to the spinal nerve roots and spinal cord. These complications can occur despite the use of imaging modalities, such as radiographs, fluoroscopy, and computerized axial tomography (CAT) scans. A-Mode ultrasound (US), a nonionizing modality, merits study for its possible use in such a type of surgery. Purpose The purpose of the study was to determine the utility of A-mode US during pedicle screw placement, to characterize the approach to the marrow-cortex interface, and to obtain the signature profiles of cortex perforations. Study design A-Mode data were generated on insertion of a forward-viewing transducer (FVT) and a side-viewing transducer (SVT) to successively greater drilled depths along the insertion pathway. A-Mode broadband US backscatter (BUB) pedicle screw emulation experiments were conducted with transducers inserted into drilled sheep vertebral bodies. BUB amplitude patterns were observed and analyzed. Descriptive statistics were used. Methods In vitro acoustic experiments on vertebral bodies in a water bath were performed with two 1-MHz unfocused transducers to measure sound speed, broadband US attenuation, and backscatter coefficients. Micro-CAT scan three-dimensional (3-D) images of 10 disarticulated vertebral bodies were obtained pre- and postdrilling done in 5-mm depth increments with a flat-bottom drill. BUB patterns were noted of transducers inserted through rostral outer cortex, through the pedicle, and advanced to the ventral marrow-cortex interface. 2.5-MHz FVT and SVT were co-advanced in successive 5-mm increments along the insertion pathway, with BUBs measured at each point and the echoes composited into a single figure. Deliberate perforations of ventral cortex were made. Results Evident patterns or measures indicating the proximity of the ventral marrow-cortex interface were: 1) marrow BUB values increasing in amplitude over three distal peaks in most FVT cases (7 out of 10) and SVT cases (9 out of 10); 2) BUB ratio of marrow-cortex interface to the smallest marrow value greater than 2, in all FVT cases (10 out of 10) with FVT mean of 4.00±1.82 (2.25–8.33); and 3) a ratio of distal BUB value to starting cortex BUB in the 0. 82 to 1.62 range (mean, 0.98±0.30) in 80% of FVT cases. Ventral FVT perforations resulted in a major drop in the BUB value. Conclusions The increase in the BUB amplitudes in the distal insertion pathway suggests that, at least with a 2.5-MHz transducer, an approximate 1.5-cm US window exists in most cases, by which close approach of the ventral marrow-cortex interface could be anticipated. Other ratios may serve as stop criteria to prevent further drilling. A precipitous drop in BUB amplitude may be an indication of a cortex perforation.

Saw cuts in unicompartmental knee arthroplasty: An analysis of sawbone preparations

Unicompartmental knee arthroplasty (UKA) has become a frequently used treatment option for anteromedial osteoarthritis (OA) of the knee due to good clinical and functional results. However, serious complications like tibial plateau fractures have been reported. These can be associated with saw cuts during surgery. The purpose of this study was to analyse saw cuts during Sawbone® preparations at instructional unicompartmental knee courses and to identify potential sources of surgical error. One hundred Sawbone® preparations were performed by knee surgeons inexperienced with UKA. Sawing errors during preparation were analysed and quantified. Tibial and femoral errors can occur during preparation. At the proximal tibia three errors can be found: extended vertical cuts (A), extended horizontal cuts (B) and perforation of the posterior cortex. An ascending cut at the posterior femoral condyle (C) is possible during femoral preparation. Errors type A were found at a mean length of 2.4 mm±2.3 mm with a maximum value of 10.1 mm. In 18% errors of more than 4.0 mm were found. Type B errors showed an average value of 2.0 mm±1.7 mm with maximum values of 7.4 mm. Type C errors were found at a mean of 1.3 mm±1.0 mm (maximum value 5.1 mm). Our data showed that in 18% of the cases, vertical cutting errors of more than 4.0 mm occurred in inexperienced surgeons.

Single-Incision Percutaneous Epiphysiodesis of the Lower Extremity

The authors describe their single-incision percutaneous epiphysiodesis technique, using a cannulated reamer and curets to create a large central epiphyseal arrest under radiographic control. We reviewed our first 165 lower extremity epiphysiodesis procedure performed in 117 patients. Patients were included if follow-up was at least 2 years or skeletal maturity was reached. Successful epiphyseal arrest was documented in all patients, and there were no angular deformities. Minor complications included a seroma with superficial infection, a temporary loss of knee flexion, an asymptomatic stress fracture at the operative site, and 1 incisional burn from a hot reamer that resulted in a broadened scar. A perforation of the posterior cortex during a proximal tibial epiphysiodesis was the only major complication. None of these patients required an additional surgical procedure. Single-incision percutaneous lower extremity epiphysiodesis of the lower extremity is a reliable, safe and minimally invasive method to achieve irreversible epiphyseal arrest.

Massive sublingual haematoma following osseo-integrated implant placement in the anterior mandible

The floor of the mouth is a very vascular area. Should perforation of the lingual cortex of the mandible occur during the placement of an osseo-integrated implant, significant haemorrhage may result. We present the case of a patient who attended our unit with acute airway obstruction. Although life threatening haematoma following the placement of osseo-integrated implants in the interforaminal area of the mandible is known to occur, there continue to be sporadic reports in the literature. This shows that some practitioners are unaware of the risks involved and place implants of the wrong size and orientation.

Hematoma of the floor of the mouth and airway obstruction during mandibular dental implant placement: a case report

Hematoma of the floor of the mouth during mandibular dental implant placement is a rare but potentially life-threatening complication. A 53-year-old man developed a hematoma of the floor of the mouth following a dental implant procedure, requiring admission to the hospital. The floor of the mouth is richly vascularized by a number of branches of the submental and sublingual arteries. During a dental implant procedure in the anterior zone of the mandible, perforation of the lingual cortex may invade the floor of the mouth and therefore damage structures within the sublingual space. The anatomy of the lower portion of the anterior mandibular zone, with the mylohyoid ridge, makes it particularly vulnerable to this kind of injury, particularly in patients with atrophic mandibles. Only a few cases have been reported in the literature to date.

Is the lateral sacral fluoroscopic view essential for accurate percutaneous sacroiliac screw insertion?: An experimental study

The aim of this study was to evaluate the role of the lateral fluoroscopic view in optimising percutaneous sacroiliac screw insertion. Plastic pelvic models (n=26) were used for the introduction of 104 cannulated screws into the first and second sacral (S1 and S2) vertebral bodies, controlled with an image intensifier using either two views (inlet/outlet) for the right side (group A, n=52) or three views (inlet/outlet/lateral) for the left side (group B, n=52). The mean radiation exposure times for S1 were 18.6s and 14s, in groups A and B, respectively, and for S2 were 16.1s and 12.2s, respectively; 13 cortex perforations were noted in group A and 20 in group B. After insertion into S1, in both groups there were three cases of foraminal and none of central canal perforation, but after S2 insertion in both groups there were ten foraminal and five canal perforations. A higher incidence of misplacement of S1 screws was found in group A in comparison with group B (p=0.001), with sufficient data to support percutaneous screw fixation using inlet, outlet and lateral views rather than only inlet and outlet acquisition images.