Large symptomatic sacral Tarlov cyst in a paediatric patient: case report and technical note on a new variation of surgical technique to overcome one-way check-valve mechanism.

PURPOSE: Symptomatic Tarlov cysts in children with a possible underlying one-way check-valve mechanism are very rare. We aim to introduce a new variation of the surgical technique to overcome a check-valve mechanism. METHODS: A 15-years-old girl presented with double incontinence and anogenital numbness due to a large sacral Tarlov-cyst with possibly underlying one-way check valve mechanisms as suggested by preoperative computed tomography myelography. Intraoperatively, one-way check-valve was confirmed and could be eliminated by creating an artificial inner ostium between the Tarlov cyst and thecal sac with blunt perforation. RESULTS: Postoperatively, the patient had established normal sphincter control and sensation in the anogenital region. CONCLUSION: One-way check-valve mechanism might contribute to the symptomatology of large sacral Tarlov cysts in children. Our new variation of a surgical technique enables elimination of the check-valve mechanism without the necessity to open and close the typically very thin and fragile cyst surface and is therefore an efficacious and simple option in this situation.

Deidentifying Narrative Assessments to Facilitate Data Sharing in Medical Education.

PROBLEM: Narrative assessments are commonly incorporated into competency-based medical education programs. However, efforts to share competency-based medical education assessment data among programs to support the evaluation and improvement of assessment systems have been limited in part because of security concerns. Deidentifying assessment data mitigates these concerns, but deidentifying narrative assessments is time-consuming, resource intensive, and error prone. The authors developed and tested a tool to automate the deidentification of narrative assessments and facilitate their review. APPROACH: The authors met throughout 2021 and 2022 to iteratively design, test, and refine the deidentification algorithm and data review interface. Preliminary testing of the prototype deidentification algorithm was performed using narrative assessments from the University of Saskatchewan emergency medicine program. The algorithm's accuracy was assessed by the authors using the review interface designed for this purpose. Formal testing included 2 rounds of deidentification and review by members of the authorship team. Both the algorithm and data review interface were refined during the testing process. OUTCOMES: Authors from 3 institutions, including 3 emergency medicine programs, an anesthesia program, and a surgical program, participated in formal testing. In the final round of review, 99.4% of the narrative assessments were fully deidentified (names, nicknames, and pronouns removed). The results were comparable for each institution and specialty. The data review interface was improved with feedback obtained after each round of review and found to be intuitive. NEXT STEPS: This innovation has demonstrated viability evidence of an algorithmic approach to the deidentification of assessment narratives while reinforcing that a small number of errors are likely to persist. Future steps include the refinement of both the algorithm to improve its accuracy and the data review interface to support additional data set formats.

Six-Month Survivorship Prediction in Spinal Metastatic Patients by Oncologists Shows Reliable Prognostication.

STUDY DESIGN: A retrospective analysis of oncologist-provided prognoses vs actual survival outcomes of patients referred with Metastatic spinal cord compression (MSCC) to a supra-regional multidisciplinary team (MDT). OBJECTIVES: Prognostic scoring systems, such as the revised Tokuhashi, are commonly used to help guide the treatment of MSCC. However, scoring systems do not accommodate for the improved outcomes of contemporary cancer therapy. Oncologist-provided prognoses play an important role in real world rapid decision making. There is a paucity of evidence assessing the accuracy of the oncologist-provided prognosis. We conducted a retrospective study to evaluate this. METHODS: Data was captured between January 2015 and December 2018. Patients were split into 2 groups: Group 1 (prognosis estimated <6 months) and Group 2 (prognosis estimated >6 months). Median overall survival (mOS) and hazard ratio for death (HR) was assessed. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of the oncologist's prognosis. RESULTS: 829 patients were included. mOS in Group 1 was 5.8 months (95% CI 4.2-7.4 m), and in Group 2 mOS was not reached. Log rank test gave a Chi2 of 131 (P < .001). Cox regression analysis revealed a HR of .30 (P < .001). Area under the ROC curve was 78%. CONCLUSIONS: Oncologist-provided prognosis is accurate in this cohort of unselected, consecutive MSCC patients. It reduced reliance on scoring systems that can become outdated. Given the rapid progress in cancer treatment, the oncologist's prognostic prediction is integral in efficient and effective MSCC management to help rapidly determine surgical candidacy.

Automated grading of anatomical objective structured practical examinations using decision trees: An artificial intelligence approach.

An Objective Structured Practical Examination (OSPE) is an effective and robust, but resource-intensive, means of evaluating anatomical knowledge. Since most OSPEs employ short answer or fill-in-the-blank style questions, the format requires many people familiar with the content to mark the examinations. However, the increasing prevalence of online delivery for anatomy and physiology courses could result in students losing the OSPE practice that they would receive in face-to-face learning sessions. The purpose of this study was to test the accuracy of Decision Trees (DTs) in marking OSPE questions as a first step to creating an intelligent, online OSPE tutoring system. The study used the results of the winter 2020 semester final OSPE from McMaster University's anatomy and physiology course in the Faculty of Health Sciences (HTHSCI 2FF3/2LL3/1D06) as the data set. Ninety percent of the data set was used in a 10-fold validation algorithm to train a DT for each of the 54 questions. Each DT was comprised of unique words that appeared in correct, student-written answers. The remaining 10% of the data set was marked by the generated DTs. When the answers marked by the DT were compared to the answers marked by staff and faculty, the DT achieved an average accuracy of 94.49% across all 54 questions. This suggests that machine learning algorithms such as DTs are a highly effective option for OSPE grading and are suitable for the development of an intelligent, online OSPE tutoring system.

Chemotherapy May Obviate Prophylactic Femoral Nail Surgery for Multiple Myeloma Patients With High Mirels' Score Lesions and Impending Pathological Hip Fracture.

Bone involvement presents in >80% of patients with multiple myeloma. This causes lytic lesions for which prophylactic surgery is indicated to prevent pathological fractures if the lesion is graded ≥9/12 on Mirels' score. Although successful, these surgeries have risks and extended recovery periods. We present a case indicating myeloma chemotherapy may obviate prophylactic femoral nailing for high Mirels' score lesions in the femoral head with impending pathological hip fracture. A 72-year-old woman presented in December 2017 with back pain. A plain X-ray indicated degenerative anterolisthesis in her lumbosacral spine. Serum analysis revealed abnormal protein, globulin, alkaline phosphatase, and albumin levels while protein electrophoresis and serum immunofixation revealed raised immunoglobulin A (IgA) kappa paraprotein and kappa serum free light chains, respectively. Whole-body CT scans showed widespread lytic bone lesions and bone marrow biopsy confirmed infiltration by plasma cells. She was diagnosed with International Staging System (ISS) stage 3 multiple myeloma, which was successfully treated with bortezomib, thalidomide and dexamethasone with regular bisphosphonates that year. She presented again to the hospital in June 2020 with acute back and pelvic pain; Her paraprotein and serum-free light chains had increased significantly from her previous clinic appointment, indicating serological progression. MRI showed a relapse of the myeloma deposits in her right femoral head and spine. The deposit in her femoral head was graded 10/12 on Mirels' score, which indicated prophylactic femoral nailing. Instead, the patient was treated with daratumumab, bortezomib, and dexamethasone with escalation to monthly zoledronic acid infusions, as it was thought surgery would provide limited cytoreductive effect, preventing chemotherapy for six weeks post-surgery, potentiating pathological hip fracture and disease progression at other sites. This resulted in a complete response, thus reducing the deposits such that the femoral lesion was graded <8 on Mirels' score, improved her pain, and restored her ability to traverse stairs. She remains in complete response with ongoing daratumumab and denosumab maintenance treatment as of December 2022. Chemotherapy and bisphosphonates substantially reduced the myeloma deposit in the femoral head such that indications of prophylactic surgery were eliminated according to Mirels' score recommendations. This reduced the risk of pathological hip fracture whilst eliminating surgical complications. Further research should be conducted into the safety and efficacy of this treatment regimen in patients with high Mirels' score lesions. With this knowledge, consideration can be taken as to whether prophylactic femoral nailing is necessary given strong indications.

Case report: L5 tomita En bloc spondylectomy for oligometastatic liposarcoma with post adjuvant stereotactic ablative radiotherapy.

Introduction: Tomita En-bloc spondylectomy of L5 is one of the most challenging techniques in radical oncological spine surgery. A 42-year-old female was referred with lower back pain and L5 radiculopathy with a background of right shoulder liposarcoma excision. CT-PET confirmed a solitary L5 oligometastasis. MRI showed thecal sac indentation hence wasn't suitable for Stereotactic Ablative Radiotherapy (SABR) alone. The seeding nature of sarcoma prevents the indication of separation surgery hence excisional surgery is considered for radical curative treatment. This case report demonstrates dual-staged modified TES including the utilisation of novel techniques to allow for maximum radical oncological control in the era of SABR and lesser invasive surgery. Methods: First-stage: Carbonfibre pedicle screws planned from L2 to S2AI-Pelvis, aligned, to her patient-specific rods. Radiofrequency ablation of L5 pedicles prior to osteotomy was performed to prevent sarcoma cell seeding. Microscope-assisted thecal sac tumour separation and L5 nerve root dissection was performed. Novel surgical navigation of the ultrasonic bone-cutter assisted inferior L4 and superior S1 endplate osteotomies. Second-stage: Vascular-assisted retroperitoneal approach at L4-S1 was undertaken protecting the great vessels. Completion of osteotomies at L4 and S1 to En-bloc L5: (L4 inferior endplate, L4/5 disc, L5 body, L5/S1 disc and S1 superior endplate). Anterior reconstruction used an expandable PEEK cage obviating the need for a third posterior stage. Reinforced with a patient-specific carbon plate L4-S1 promontory. Results: Patient rehabilitated well and was discharged after 42 days. Cyberknife of 30Gy in 5 fractions was delivered two months post-op. Despite left foot drop, she's walking independently 9 months post-op. Conclusion: These are challenging cases require a truly multi-disciplinary team approach. We share this technique for a dual stage TES and metal-free construct with post adjuvant SABR to achieve maximum local control in spinal oligometastatic disease. This case promotes our modified TES technique in the era of SABR and separation surgery in carefully selected cases.

An Examination of the Number of Adolescent Scoliotic Curves That Are Braceable at First Presentation to a Scoliosis Service.

Adolescent idiopathic scoliosis (AIS) affects between 0.5% and 5.2% of adolescents and is progressive in two-thirds of cases. Bracing is an effective non-operative treatment for AIS and has been shown to prevent up to 72% of curves from requiring surgery. This paper explores the presentation of AIS in the UK and identifies who would be suitable for bracing, as per guidelines published by the Scoliosis Research Society (SRS) and British Scoliosis Society (BSS), through curve severity and skeletal maturity at presentation. There were 526 patients with AIS eligible for inclusion across three tertiary referral centres in the UK. The study period was individualised to each centre, between January 2012 and December 2021. Only 10% were appropriate for bracing via either SRS or BSS criteria. The rest were either too old, skeletally mature or had a curve size too large to benefit. By the end of data collection, 38% had undergone surgery for their scoliosis. In the UK, bracing for AIS is only suitable for a small number at presentation. Future efforts to minimise delays in specialist review and intervention will increase the number of those with AIS suitable for bracing and reduce the number and burden of operative interventions for AIS in the UK.

Dual modality of vertebral body tethering : anterior scoliosis correction versus growth modulation with mean follow-up of five years.

AIMS: Vertebral body tethering (VBT) is a non-fusion technique to correct scoliosis. It allows correction of scoliosis through growth modulation (GM) by tethering the convex side to allow concave unrestricted growth similar to the hemiepiphysiodesis concept. The other modality is anterior scoliosis correction (ASC) where the tether is able to perform most of the correction immediately where limited growth is expected. METHODS: We conducted a retrospective analysis of clinical and radiological data of 20 patients aged between 9 and 17 years old, (with a 19 female: 1 male ratio) between January 2014 to December 2016 with a mean five-year follow-up (4 to 7). RESULTS: There were ten patients in each group with a total of 23 curves operated on. VBT-GM mean age was 12.5 years (9 to 14) with a mean Risser classification of 0.63 (0 to 2) and VBT-ASC was 14.9 years (13 to 17) with a mean Risser classification of 3.66 (3 to 5). Mean preoperative VBT-GM Cobb was 47.4° (40° to 58°) with a Fulcrum unbend of 17.4 (1° to 41°), compared to VBT-ASC 56.5° (40° to 79°) with 30.6 (2° to 69°)unbend. Postoperative VBT-GM was 20.3° and VBT-ASC Cobb angle was 11.2°. The early postoperative correction rate was 54.3% versus 81% whereas Fulcrum Bending Correction Index (FBCI) was 93.1% vs 146.6%. The last Cobb angle on radiograph at mean five years' follow-up was 19.4° (VBT-GM) and 16.5° (VBT-ASC). Patients with open triradiate cartilage (TRC) had three over-corrections. Overall, 5% of patients required fusion. This one patient alone had a over-correction, a second-stage tether release, and final conversion to fusion. CONCLUSION: We show a high success rate (95%) in helping children avoid fusion at five years post-surgery. VBT is a safe technique for correction of scoliosis in the skeletally immature patient. This is the first report at five years that shows two methods of VBT can be employed depending on the skeletal maturity of the patient: GM and ASC. Cite this article: Bone Jt Open 2022;3(2):123-129.

Dynamic Radiographs in Assessing Stability of Cervical Spine Fractures: A Multicentre Study.

BACKGROUND: In the management of a trauma patient with cervical spine injury, the need for accurate diagnostic imaging is key to ensure correct management. Different classification systems have been developed including the Subaxial Injury Classification (SLIC) system and AO cervical spine fracture classification. Through a multicentre study, we have identified a group of cases where the use of CT alone to classify fractures by either SLIC or AO score may be deficient and the use of dynamic cervical spine radiographs could help identify instability. METHODS: Three level 1 trauma centers retrospectively reviewed patients with cervical spine injuries. Cervical spine radiographs (AP and lateral) were undertaken in collar, in all patients with suspected cervical spine injury within 2 weeks, followed by reanalysis of scoring systems. RESULTS: Eleven cases were identified in total, and 72% were male with a mean age of 65 years, with approximately 54% being older than 70 years. All patients reported their pain as severe using the Visual Analogue Scale scale. The predynamic radiograph mean SLIC score was 0.73, which is in contrast to the postdynamic radiograph mean SLIC score of 6. The statistical significance (P = 0.004) was found using the Wilcoxon signed-rank test. CONCLUSION: Supine imaging eliminates the gravitational loads normally exerted on the c-spine. The cases show assumed cervical stability based on CT, but dynamic c-spine radiographs subsequently demonstrated instability. Therefore, we suggest a combination of SLIC and AO classification using radiologic imaging to classify fracture and correlate clinical symptoms with persistent neck pain, which warrants a Miami-J collar and dynamic c-spine radiograph to assess stability with re-evaluation of scoring.

Surgeon-Directed Neuromonitoring in Adolescent Spinal Deformity Surgery Safely Assesses Neurological Function.

Background Spinal deformity correction is associated with the risk of intra-operative neurological injury. Surgeon-directed monitoring (SDM) of transcranial motor-evoked potentials (TcMEP) is an option to monitor intra-operative spinal cord function. We report a retrospective analysis of a prospective database to assess the safety of this technique in spinal deformity correction in adolescent patients. Methods Surgeon-directed neuro-monitoring was utilised in 142 consecutive deformity correction surgeries (2012-2017). Surgeons were responsible for electrode placement, intra-operative stimulation, and interpretation of TcMEP data. If waveform disappearance occurred in the lower limb (LL), the surgeon would re-stimulate after excluding technical or anaesthetic factors. Failure to return normal waveforms led to maneuver reversal and reducing distractive force and ensuring subsequent return to baseline. Wake up test and ankle clonus followed by staging surgery was considered if the LL waveforms failed to return indicating potential motor injury. Results Of 142 patients, three cases (2.11%) had a complete visual loss of LL signals that did not resolve with anaesthetic stabilisation, leading to reversed surgical manoeuvre and staged surgery. No cases with permanent neurological dysfunction were recorded. This outcome supports surgeon-directed monitoring as a safe monitoring option, as an alternative to neurophysiologist-led monitoring. It also provides evidence in support of the waveform disappearance criteria as a safe TcMEP warning criterion with a 100% negative predictive value. Conclusions Where there is a lack of availability of trained neurophysiologists, surgeon-directed neuro-monitoring is a safe and reliable method of preventing intra-operative neurological injury amongst adolescent patients undergoing deformity correction.

Is the AO spine thoracolumbar injury classification system reliable and practical? a systematic review.

Controversy surrounding the classification of thoracolumbar injuries has given rise to various classification systems over the years, including the most recent AOSpine Thoracolumbar Injury Classification System (ATLICS). This systematic review aims to provide an up-to-date evaluation of the literature, including assessment of a further three studies not analysed in previous reviews. In doing so, this is the first systematic review to include the reliability among non-spine subspecialty professionals and to document the wide variety between reliability across studies, particularly with regard to sub-type classification. Relevant studies were found via a systematic search of PubMed, EBESCO, Cochrane and Web of Science. Data extraction and quality assessment were conducted in line with Cochrane Collaboration guidelines. Twelve articles assessing the reliability of ATLICS were included in this review. The overall inter-observer reliability varied from fair to substantial, but the three additional studies in this review, compared to previous reviews, presented on average only fair reliability. The greatest variation of results was seen in A1 and B3 subtypes. Least reliably classified on average was A4 subtype. This systematic review concludes that ATLICS is reliable for the majority of injuries, but the variability within subtypes suggests the need for further research in assessing the needs of users in order to increase familiarity with ATLICS or perhaps the necessity to include more subtype-specific criteria into the system. Further research is also recommended on the reliability of modifiers, neurological classification and the application of ATLICS in a paediatric context.

Reproducibility and reliability analysis of the Luk Distal Radius and Ulna Classification for European patients with adolescent idiopathic scoliosis.

PURPOSE: Current clinical and radiological methods of predicting a patient's growth potential are limited in terms of practicality, accuracy and known to differ in different races. This information influences optimal timing of bracing and surgical intervention in adolescent idiopathic scoliosis (AIS). The Luk classification was developed to mitigate limitations of existing tools. Few reliability studies are available and are limited to certain geographical regions with varying results. This study was performed to analyze reproducibility and reliability of the Luk Distal Radius and Ulna Classification in European patients. METHODS: This is a radiological study of 50 randomly selected left hand and wrist radiographs of patients with AIS referred to a tertiary referral centre. They were assessed for bone maturity using the Luk Distal Radius and Ulna Classification. Assessment was performed twice by four examiners at an interval of one month. Statistical analysis was performed using the intraclass correlation (ICC) method to determine the reliabilities within and between the examiners. RESULTS: In total, 50 radiographs (M:F = 13:37) with a mean age of 13.7 years (10 to 18) were assessed for reliability. The inter-rater ICC value was 0.918 for radius assessment and 0.939 for ulna assessment. The intra-rater ICC values for radius assessment ranged between 0.897 and 0.769 and between 0.948 and 0.786 for ulna assessment. There was near perfect correlation for both assessments. CONCLUSION: This study provides independent evidence that the Luk Distal Radius and Ulna Classification is a reliable tool for assessment of skeletal maturity for European patients. Minimal clinical experience is required to reliably utilize it. LEVEL OF EVIDENCE: IV.

Patient Knowledge and Perception of Radiation Risk in Diagnostic Imaging: A Cross-Sectional Study.

BACKGROUND: Informed consent dictates that patients appreciate the risks and benefits of imaging techniques that use ionizing radiation. Computed tomography (CT) and X-ray carry a stochastic lifetime risk of inducing malignancy. This risk is difficult to convey and often overlooked. OBJECTIVE: This work aims to establish some basics regarding patient knowledge and perception of medical imaging to facilitate an informed consent process. METHOD: A questionnaire survey was conducted in a general orthopedic outpatient clinic in a United Kingdom tertiary center. RESULTS: There were 219 respondents. Twenty-two percent understood that CT produces ionizing radiation associated with cancer risk, but only 6% knew about cancer risk from natural background radiation. Only 25% knew that CT has a higher cancer risk than X-ray. The majority (93%) knew that smoking poses higher risk than X-rays. The Internet as an information source was statistically associated with concern about X-rays. CONCLUSIONS: Patients underestimated CT cancer risk and were unable to compare risk between imaging modalities. Risk can be more effectively conveyed using better known relatable risks as comparators. Patient groups associated with lower knowledge, most in need of education, were highlighted.

Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model.

INTRODUCTION: Lumbar spinal stenosis is degenerative narrowing of the spinal canal and/or intervertebral foramen causing compression of the spinal cord and nerve roots. Traditional decompression techniques can often cause significant trauma and vertebral instability. This paper evaluates a method of increasing pedicle length to decompress the spinal and intervertebral foramen, which could be done minimally invasive. METHODS: Three Sawbone (Sawbones Europe, Sweden) and 1 cadaveric lumbar spine underwent bilateral pedicle distraction at L4. A pedicle channel was drilled between the superior articular process and transverse process into the vertebral body. The pedicles underwent osteotomy at the midpoint. Screws were inserted bilaterally and fixated distraction of 0 mm, 2 mm, 4 mm and 6 mm. CT images were taken at each level of distraction. Foramen area was measured in the sagittal plane at L3/4. Spinal canal area was measured at L4 in the axial images. The cadaver was used to evaluate safety of osteotomy and soft tissue interactions preventing distraction. Statistical analysis was by student paired t-test and Pearson rank test. RESULTS: Increasing distraction led to greater Spinal canal area. From 4.27 cm2 to 5.72 cm2 (p = 0.002) with 6 mm distraction. A Maximal increase of 34.1%. Vertebral foramen area also increased with increasing pedicle distraction. From 2.43 cm2 to 3.22 cm2 (p = 0.022) with 6 mm distraction. A maximal increase of 32.3%. The cadaver spinal canal increased in area by 21.7%. The vertebral foramen increased in area by 36.2% (left) and 22.6% (right). DISCUSSION: For each increase in pedicle distraction the area of the spinal and vertebral foramen increases. Pedicle distraction could potentially be used to alleviate spinal stenosis and root impingement. A potential osteotomy plane could be at the midpoint of the pedicle with minimal risk to nerve roots and soft tissue restrictions to prevent distraction.

Pelvic fracture urethral injury in males-mechanisms of injury, management options and outcomes.

Pelvic fracture urethral injury (PFUI) management in male adults and children is controversial. The jury is still out on the best way to manage these injuries in the short and long-term to minimise complications and optimise outcomes. There is also little in the urological literature about pelvic fractures themselves, their causes, grading systems, associated injuries and the mechanism of PFUI. A review of pelvic fracture and male PFUI literature since 1757 was performed to determine pelvic fracture classification, associated injuries and, PFUI classification and management. The outcomes of; suprapubic catheter (SPC) insertion alone, primary open surgical repair (POSR), delayed primary open surgical repair (DPOSR), primary open realignment (POR), primary endoscopic realignment (PER), delayed endoscopic treatment (DET) and delayed urethroplasty (DU) in male adults and children in all major series have been reviewed and collated for rates of restricture (RS), erectile dysfunction (ED) and urinary incontinence (UI). For SPC, POSR, DPOSR, POR, PER, DET and DU; (I) mean RS rate was 97.9%, 53.9%, 18%, 58.3%, 62.0%, 80.2%, 14.4%; (II) mean ED rate was 25.6%, 22.5%, 71%, 37.2%, 23.6%, 31.9%, 12.7%; (III) mean UI rate was 6.7%, 13.6%, 0%, 14.5%, 4.1%, 4.1%, 6.8%; (IV) mean FU in months was 46.3, 29.4, 12, 61, 31.4, 31.8, 54.9. For males with PFUI restricture and new onset ED is lowest following DU whilst UI is lowest following DPOSR. On balance DU offers the best overall outcomes and should be the treatment of choice for PFUI.

An In Vitro Biomechanical Study on Ovine Rib Flexibility With Increasing Deconstruction-As an Alternative to Rib Resection for Costoplasty.

STUDY DESIGN: An in vitro biomechanical study into the effect of rib deconstruction on the flexibility in ovine ribs, using three-point bending. OBJECTIVE: To examine the feasibility and possible effectiveness of a more conservative costoplasty using an in vitro animal model. SUMMARY OF BACKGROUND DATA: Costoplasty remains useful in the treatment of adolescent idiopathic scoliosis, rib hump, and associated chest wall deformities. However, traditional costoplasty increases morbidity and blood loss. METHODS: Ribs 2-10 were dissected from four fresh half ovine rib cages. The ribs were randomly allocated to Groups 1 to 4. The ribs underwent deconstruction, 10 mm from the lateral tubercle and 30 mm long, according to their group: Group 1 = control; Group 2 = convex cortical bone removed; Group 3 = convex cortical and cancellous bone removed; Group 4 = all but the ventral cortex is removed. Flexibility was tested by loading the concave side of each rib while fixed at the rib head and equidistant from the center of the resected area. The ribs were deformed at 0.5 mm/s up to a maximum load of 9.99 kg or fracturing. Load was plotted against displacement to find the load/displacement coefficient for each group. Statistical analysis was by an analysis of variance with Tukey's honestly significant difference post hoc testing. RESULTS: The load/displacement coefficients were as follows: Group 1 = 131.93 (±27.52) N/mm, Group 2 = 93.36 (±40.71) N/mm, Group 3 = 88.66 (±25.84) N/mm, and Group 4 = 29.69 (±29.11) N/mm. Group 4 was significantly less stiff than Groups 1, 2, and 3 (p < .01). No ribs in Groups 1, 2, and 4 fractured. Five of 8 ribs in Group 3 fractured during loading. CONCLUSIONS: Deconstructing the rib down to the concave side significantly increases the flexibility by approximately 4.5 times. Despite large removal of bone, it retains the ability to withstand 10 kg of load without fracture.

Unstable elbow dislocations: a case report of a new surgical technique.

This case report describes our first clinical experience of a previously described new surgical technique for the treatment of unstable simple elbow dislocations. The technique utilises a central strip of the distal triceps tendon which is harvested proximally at the musculotendonous junction and left attached at its insertion on the olecranon. The strip is the passed through the olecranon fossa and attached to the coronoid process to stabilise the joint. We encountered an early postoperative complication that led to a modification of our technique and ultimately an excellent recovery of a stable pain free joint with a full range of movement.

Slice Encoding for Metal Artefact Correction in magnetic resonance imaging examinations for radiotherapy planning.

BACKGROUND AND PURPOSE: Magnetic resonance (MR) and computed tomography (CT) images are degraded in the presence of metallic implants. We investigate whether SEMAC (Slice Encoding for Metal Artifact Correction) MR is advantageous for radiotherapy (RT) planning. METHODS: Conventional and SEMAC MR protocols were compared (1.5T). A spine fixation device suspended in gelatine, two patients with spine fixation devices and six patients with bilateral hip replacements were scanned with both conventional and SEMAC protocols. In spine patients the visibility of the spinal canal and spinal cord was assessed; in prostate patients, the visibility of the prostate, pelvic structures and the pelvic girdle. RESULTS: The signal loss volume surrounding the spine fixation device was reduced by approximately 20% when the SEMAC protocol was employed, and registration errors were reduced. For spine patients, the spinal canal was completely visible only using the SEMAC protocol. In hip replacement patients, metal artifacts were local; the signal loss extended to the internal surface of the acetabulum in eight implants with conventional protocols, but only in four using SEMAC. CONCLUSIONS: SEMAC MR contributes towards correct co-registration of MR and CT images for RT planning, and is particularly relevant when the TV or OARs are close to implants.

Odontoid process fractures: the role of the ligaments in maintaining stability. A biomechanical, cadaveric study.

AIMS: We wished to investigate the role of the cervical ligaments in maintaining atlantoaxial stability after fracture of the odontoid process. METHODS: We dissected eight fresh-frozen cadaveric cervical spines to prepare the C1 and C2 vertebrae for biomechanical analysis. The C1 and C2 blocks were mounted and biomechanical analysis was performed to test the stability of the C1-C2 complex after cutting the odontoid process to create an Anderson and D'Alonzo type II fracture then successive division of the atlantoaxial ligaments. Biomechanical analysis of stiffness, expressed as Young's modulus, was performed under right rotation, left rotation and anterior displacement. RESULTS: The mean Young's modulus in anterior displacement decreased by 37% when the odontoid process was fractured (p = 0.038, 95% confidence interval 0.04-1.07). The mean Young's modulus in anterior displacement decreased proportionally (compared to the previous dissection) by the following percentages when the structures were divided: facet joint capsules (bilateral) 16%, ligamentum flavum 27%, anterior longitudinal ligament 10%. These differences did not reach statistical significance (p > 0.05). DISCUSSION: We have found that the odontoid process itself may account for up to 37% of the stiffness of the C1-C2 complex and that soft tissue structures account for further resistance to movement. We suggest magnetic resonance imaging (MRI) of the soft tissues in the acute setting of a minimally displaced odontoid process fracture to plan management of the injury. If the MRI determines that there is associated ligament injury it is likely that the fracture is unstable and we would suggest operative management.

Unstable elbow dislocations: the description and cadaveric feasibility study of a new surgical technique.

INTRODUCTION: A small proportion of simple elbow dislocations are grossly unstable and joint congruence is not maintained after reduction. In this rare situation operative treatment is indicated. We describe a new intra articular reconstruction that utilises a slip of triceps tendon to provide immediate stability to the elbow. METHODS: We assessed 20 cadaveric elbows, measuring the length of triceps tendon available and required to complete the reconstruction. We then sequentially sectioned the ligamentous stabilisers of an elbow before performing the new technique. We measured the displacement and angulation possible at the elbow before and after the reconstruction. RESULTS: All 20 elbows had sufficient triceps tendon length to complete the new technique. Prior to the reconstruction greater than 30 mm of joint distraction and 90 degrees varus or valgus angulation was possible. Following the reconstruction it was not possible to re-dislocate the elbow. Only 2 mm of joint distraction and 10 degrees of varus or valgus angulation were possible with the triceps graft fixed in position. DISCUSSION: This novel technique elegantly avoids many of the problems associated with current methods. We have demonstrated that it is technically feasible and easy to perform with minimal equipment requirements or costs.