Hook Placement Research Articles

Radiographic and Clinical Outcomes of Transverse Process Hook Placement at the Proximal Thoracic Upper Instrumented Vertebra in Adult Spinal Deformity Surgery.

Few studies have reported radiographic and clinical outcomes of transverse process hook (TPH) placement at the proximal thoracic upper instrumented vertebra (UIV) in adult spinal deformity (ASD) surgery. This study aims to investigate radiographic and clinical outcomes of TPH placement at the UIV for ASD surgery. This is a retrospective cohort of 56 patients with ASD (age, 59 ± 13 years; followup, 44 ± 19 months) from Johns Hopkins Hospital, who underwent long posterior spinal fusion to the proximal thoracic spine (T2-5). Visual analogue scale (VAS) for back pain, Oswestry Disability Index (ODI), 36-item Short Form health survey scores, thoracic kyphosis (TK), lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence, proximal junctional kyphosis (PJK) angle, PJK incidence, pattern of PJK, grades of TPH dislodgement, revision surgery, and factors associated with high-grade TPH dislodgement were analyzed. VAS for back pain and ODI values improved significantly from preoperatively to final follow-up. Mean change in PJK angle was 12° (range, 0.5°-43°). Twenty patients (36%) developed PJK, of whom 13 had compression fractures at 1 vertebra distal to the UIV (UIV-1). Final TPH position was stable in 42 patients (75%). In most patients (86%), TPH dislodgement did not progress after 6-month postoperative follow-up. Three patients (5.3%) underwent revision surgery to extend the fusion because of symptomatic PJK. Unstable TPH position was associated only with revision surgery and TK. TPH placement at the proximal thoracic UIV for long fusion showed favorable clinical and radiographic outcomes in terms of the incidence of PJK and mean PJK angle at mean 44-month follow-up. TPHs placed in the proximal thoracic UIV were in stable position in 75% of patients. Compression fracture at UIV-1 was the most common pattern of PJK. PJK angle progression was greater in revision cases and in patients with greater preoperative thoracic kyphosis.

Can placement of hook at the upper instrumented level decrease the proximal junctional kyphosis risk in adolescent idiopathic scoliosis?

Proximal junctional kyphosis is a commonly encountered clinical and radiographic phenomenon after pediatric and adolescent spinal deformity surgery that may lead to postoperative deformity, pain, and dissatisfaction. The purpose of the study was to identify whether the placement of transverse process hooks is an effective way to prevent PJK. Adolescent idiopathic scoliosis patients who underwent posterior spinal fusion between November 2015 and May 2019 were retrospectively analyzed. A minimum 2-year follow-up was required. Demographic and surgical data included UIV level type of instrumentation (hook vs screw) were reported. Radiologic parameters included main curve Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), and proximal junctional angle (PJA) were assessed. Patients were divided into two groups based on the type of instrumentation at the UIV level whether placement of hook versus pedicle screw. Three hundred and thirty-seven patients were included with the mean age 14.2 ± 1.9years. Thirty patients (8.9%) were diagnosed with proximal junctional kyphosis radiographically. PJK incidence was found 3.2% (5/154) in the hook group and 13.3% (23/172) in the screw group and the difference found statistically significant. In the PJK group, preoperative thoracic kyphosis and the degree of kyphosis correction were also significantly higher than non-PJK patients. Placement of transverse process hooks at the UIV level in posterior spinal fusion surgery for AIS patients was associated with decreased risk of PJK. A larger preoperative kyphosis and greater degree of kyphosis correction correlated with PJK.

Safe Zones for Temporal Muscle Hook Retraction: A Technical Note

The temporal muscle (TM) needs to be dissected and reflected downward in some anterolateral cranial approaches, and failing to preserve its integrity could have severe functional and cosmetic consequences. Most articles focus on techniques to prevent vascular injury during retrograde dissection or techniques to preserve the facial nerve; however, information on how to take care of the muscle during hook retraction is limited. We presented an anatomic study of vascularization of the TM, and we established safe areas for muscular hook retraction. We dissected 16 TMs in 8 cadaveric heads. The TM was reflected downward, and we measured the distance between the anterior branch of the posterior deep temporal artery (PDTA) and the frontozygomatic suture and the distance between the posterior branch of the PDTA and the external auditory meatus projection. The average distance between the anterior branch of the PDTA and the frontozygomatic suture was 19.5 mm (range, 14-26 mm). The average distance between the posterior branch of the PDTA and the external auditory canal was 37.1 mm (range, 31-43 mm). We established 2 safe zones for hook placement: an anterior safe zone 14 mm posterior to the frontozygomatic suture and a posterior safe zone 30 mm anterior to the external auditory meatus. We delimited 2 safe zones for hook placement during TM retraction aiming to avoid direct vascular damage in anterolateral cranial approaches.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

BACKGROUND CONTEXT Proximal junctional kyphosis (PJK) is a significant concern following long posterior spinal fusion. Biomechanically, proximal hook placement at the upper instrumented vertebra have been shown to allow a more gradual transition to normal motion compared with pedicle screws in a long posterior instrumented spinal fusion. PURPOSE The purpose of this study was to evaluate the risk of developing proximal junctional kyphosis with sublaminar hooks versus pedical screw fixation at the upper instrumented vertebra of a posterior spine fusion for adult spinal deformity. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Consecutive patients who underwent elective posterior spinal fusion for adult deformity at a single academic institution from 2008 to 2014 with a minimum of 2years of follow-up were identified. Patients with proximal hooks and those with proximal screws were separated into 2 groups. OUTCOME MEASURES Preoperative, first postoperative, and final postoperative standing radiographs were reviewed. Radiographic assessments included: sagittal vertical axis (SVA), pelvic incidence, lumbar lordosis, thoracic kyphosis, T1 pelvic angle (TPA) and kyphosis at one- and two-levels above the upper instrumented vertebra (UIV+1, UIV+2). Two common methods of assessing PJK were used. At two levels above the upper instrumented vertebra (UIV+2), kyphosis greater than 10° and more than a 10° increase from the preoperative film was defined as PJK. At UIV+1, PJK was defined as a greater than 15° increase from the preoperative film. METHODS Multivariate logistic regression was used to test the association between proximal hooks and development of PJK while controlling for differences in patient and operative characteristics. RESULTS A total of 142 patients fulfilled inclusion criteria. Average follow-up was (52.8 ±29.1 months). There were no significant differences in demographic characteristics between the 2 groups. Patients with sublaminar hooks at the UIV presented with significantly fewer instances of PJK using UIV+1 (44.0% vs. 63.1%; p=.029) and UIV+2 (52.0% vs. 76.1%; p=.048) measurements compared to those who received pedicle screws at the UIV. Patients with laminar hooks experienced a significantly greater increase in SVA from preoperative to immediate postoperative (13.6±11.6 mm vs. 1.8±12.4 mm; p CONCLUSIONS Laminar hooks at the upper instrumented vertebra were associated with reduced rates of PJK compared with pedicle screws in patients who undergo deformity-correcting spine fusion for adult spinal deformity. This information may be useful for operative planning to minimize the occurrence of PJK after adult deformity surgery.

Influence of hook type and live bait on the hooking performance of inline spinners in the context of catch-and-release brook trout Salvelinus fontinalis fishing in lakes

The objective of catch-and-release angling is for the fish to survive with minimal fitness consequences. However, fish survival can be compromised by a number of factors, especially anatomical hooking location. To evaluate whether hook type or bait influence hooking outcomes, we tested different combinations of hook (treble or single siwash hooks) and bait (hook tipped with worm or no worm) while angling for brook trout (Salvelinus fontinalis) with inline spinner-style fishing lures. The study was conducted at spring water temperatures (∼20°C) in small lakes stocked with trout in southwestern Quebec, Canada. Incidences of hooking in the interior of the mouth (i.e. internal hooking) were uncommon (19%), did not differ significantly between hook types or bait treatments, and occurred independently of fish size. Reflex impairments after hook removal were not related to hook or bait treatment. Short-term mortality was quantified with 24h holding in net pens and was determined to be infrequent for all treatment groups (treble/worm: 6%; treble/no worm: 5%; single/worm: 2%; single/no worm: 0%). Although no fish were hooked in the gills, esophagus, stomach, odds of mortality increased by 14.21 when fish were hooked internally, which is consistent with the position that hook placement is an important predictor of the fate of fish released by anglers. However, our finding that neither hook nor bait type significantly increased the odds of internal hooking, bleeding, reflex impairment, or mortality in this study suggests that restrictions imposed on the use of baited lures or certain hook types attached to lures when fishing may have little influence on short-term catch-and-release mortality of brook trout at these temperatures.

Computed Tomographic Morphometric Study of the Occipital Bone Thickness in 100 Adult, Moroccan Patients

Background: Occipital cervical fixation (OCF) is an important and difficult technic and has certain risks due to its relation with adjacent special anatomic features. One of specific areas to perform screw fixation and to prevent technical failures is the thickness of the occipital bone which require detailed morphological anatomical knowledge. To our knowledge, no published study has provided thicknesses of occiput in African Continent. Objective: The aim of this study was to evaluate occipital bony thickness in Moroccan population in order to determine the variability of the occipital bone thickness and to assess the feasibility and safety of hook and screw placement in these patients. Patients and methods: We evaluated occipital bony thickness using computed tomography (CT) imaging in 100 patients (30 females and 70 males; age range, 18–70; mean, 36.2 ± 11.9 years). Axial CT cutting was made at 1.25 mm intervals. CT measurements were performed on the bone windows at two levels starting at 1 cm under the external occipital protuberance (EOP) and 1 cm inferior to this level. Three measurements were performed both sides at 1 cm interval. We acquired 14 values. Results: The mean thickness of occipital bones varied between 10.003 to 13.964 mm in the left and 10.747 to 13.715 mm in the right (± 2.8) and between 9.845 to 11.478 mm in the left and 9.903 to 11.371 in the right (± 2.5) at 1 cm and 2 cm above EOP respectively. The thickest point was in the midline with 17.366 mm and 12.579 mm at 1 cm and 2 cm above EOP respectively, Intra-individual and inter-individual discrepancies are found between left and right sides (p<0.05) but not between age and sex at two levels in our adult patients. Conclusion: Our radiological study findings suggest that there were significant differences between individuals and ethnics. The preoperative CT scans of occipital bony thickness as the pedicle size should be thoroughly analysed of patients undergoing occipital cervical fixation. These are essential for successful intraoperative fusion and to further decrease the risk of occipito-cervical fusion.

MEEC Models for RFIC Design Based on Coupled Electric and Magnetic Circuits

This paper proposes the use of coupled electric and magnetic circuits in the schematic models of high frequency integrated circuits, as an effective method to model the global inductive effects and coupling. These pairs of coupled circuits, called magneto-electro-equivalent circuit (MEEC) models, are obtained by partitioning the computational domain into several subdomains, each having its own electromagnetic field regime. The model reduction method we propose can be used not only to derive the full coupled electric and magnetic circuit model of a device starting from its layout, but also to correct the electric schematic by adding inductive parasitic effects. The MEEC approach uses special boundary conditions—called magnetic/electric hooks—on the interfaces between the subparts in which the computational domain is partitioned. The success of the correct extraction of inductive effects rely on the terminal reduction, i.e., the correct placement of magnetic hooks on the interfaces. In order to find this placement, a heuristic approach based on IC layout analysis is proposed. In order to consider the parasitic inductive couplings, the electric schematic circuit graph is enhanced with geometric information from the layout (e.g., node coordinates). The MEEC-based approach is validated for a real example of a low noise amplifier. Its initial layout design proved to be wrong only after the fabrication and characterization of the first prototype. The use of the inductive parasitic extraction tool, based on the MEEC approach, would have prevented this. MEEC is an alternative approach to vector potential equivalent circuit, with respect to which advantages and disadvantages are discussed.

Phacoemulsification using 8 flexible iris hooks in a patient with a short eye, small pupil, and phacodonesis

We describe a technique that uses flexible iris hooks to dilate and stabilize the capsular bag in a patient with a very deep set and small eye, narrow palpebral fissure, shallow anterior chamber, and very small pupil, who was scheduled for routine phacoemulsification for a white cataract. At the time of iris hook placement, the capsular bag was noted to be markedly unstable. The patient was managed successfully with phacoemulsification of the lens using 4 iris hooks to dilate the pupil and 4 iris hooks to stabilize the capsular bag during surgery. A foldable posterior chamber 3-piece intraocular lens was fixated in the ciliary sulcus. Neither author has a financial or proprietary interest in any material or method mentioned.

Improved type specialization for dynamic scripting languages

Type feedback and type inference are two common methods used to optimize dynamic languages such as JavaScript. Each of these methods has its own strengths and weaknesses, and we propose that each can benefit from the other if combined in the right way. We explore the interdependency between these two methods and propose two novel ways to combine them in order to significantly increase their aggregate benefit and decrease their aggregate overhead. In our proposed strategy, an initial type inference pass is applied that can reduce type feedback overhead by enabling more intelligent placement of profiling hooks. This initial type inference pass is novel in the literature. After profiling, a final type inference pass uses the type information from profiling to generate efficient code. While this second pass is not novel, we significantly improve its effectiveness in a novel way by feeding the type inference pass information about the function signature, i.e., the types of the function's arguments for aspecific function invocation. Our results show significant speedups when using these low-overhead strategies, ranging from 1.2x to 4x over an implementation that does not perform type feedback or type inference based optimizations. Our experiments are carried out across a wide range of traditional benchmarks and realistic web applications. The results also show an average reduction of 23.5% in the size of the profiled data for these benchmarks.

Pilot Study Evaluation of Standard Laparoscopic Suturing and a Novel Parenchymal Apposition Mechanism for Minimally Invasive Renal Reconstruction

The most technically demanding portion of a laparoscopic partial nephrectomy is the renorrhaphy. The purpose of this study was to determine whether a parenchymal apposition mechanism (PAM) device would be as effective as standard laparoscopic technique (SLT) with respect to efficiency, capability, and safety of renal defect closure. In this pilot study, participants were recruited to perform surgical reconstruction of a standardized renal parenchymal defect with both SLT and the PAM. The PAM prototype was engineered using two salmon egg hooks connected by absorbable suture and placed within a V-shaped foam delivery mechanism. After hook placement, tensioning of the connecting suture using a Weck clip apposed the defect edges. Each participant performed a single closure with SLT and with the PAM device of a standardized defect in ex vivo porcine kidneys. Closure time, tissue trauma/damage during closure, and the intraparenchymal pressure were recorded. A total of 13 subjects, 7 medical students, 3 residents, 2 fellows, and 1 attending were enrolled. There was no statistical difference between the two methods of closure in average time for closure. In a subgroup analysis of subjects who had performed laparoscopic reconstructive procedures as the primary surgeon, SLT was significantly faster than PAM (P=.036). Mean pressures achieved in attempted closure using SLT and PAM were not significantly different (0.38 N for both groups; P=.99). The mean parenchymal trauma rating was not significantly different between the groups; however, the upper limit of the range of trauma ratings was greater in the standard closures. This pilot study demonstrated the feasibility of PAM use in an ex vivo porcine kidney model. Additional testing and continued design modifications are necessary to explore its use in laparoscopic reconstruction of the kidney and other organs.

Surgical Treatment of Adult Idiopathic Scoliosis: Long-Term Clinical Radiographic Outcomes

More adults are suffering from adult idiopathic scoliosis and seeking treatment for their spinal deformities. Adult idiopathic scoliosis can lead to painful spinal osteoarthritis, progressive deformity, spinal stenosis with radiculopathy, muscle fatigue from coronal and sagittal plane imbalance, and psychological effects with a visible deformity. Primary treatment of such conditions is conservative; however, some patients are resistant to conservative treatment or are not candidates for it, and they require surgery. Back pain is likely the most common indication for surgical treatment of scoliosis in adult patients. Pedicle screws offer 3-column purchase and a longer arm compared with hook placement on the lamina. This study is a retrospective analysis of a consecutive series of patients with adult idiopathic scoliosis who were treated with pedicle screw placement. Significant back pain relief and satisfaction can be achieved and maintained over the long term. Restoration of coronal and sagittal balance, or improvement thereof, was achieved in all patients with balance problems. This study clarified several important characteristics of adult scoliosis, and we believe that useful conclusions can be drawn regarding its surgical indications and strategies: (1) pedicle screw construct can gain effective results for treatment of adult idiopathic scoliosis due to its perceived superior power of correction; (2) younger patients present for surgery for different reasons than older patients (progressive deformity or pain); and (3) pain improvement is a more reliable outcome in older patients than younger patients, although younger patients rarely have severe pain symptoms.

견갑하 건 단독 파열에 대한 쇄골하 삽입구를 이용한 봉합술 - 술기보고 -

Purpose: For an isolated tear of the subscapularis tendon, the presented technique using a subclavian portal provides both a good angle for anchor placement and sufficient space for managing the upper portion of a subscapularis tendon tear. Materials and Methods: The conventional method needs 2 additional portals for traction, debriding the footprint and anchor fixation for repair. The presented technique requires only an anterior portal for suture management and a subclavian portal without cannula for suture anchoring and placement of suture hooks. Results: The two suture limbs of the anchor can be placed on the subscapularis tendon by the switching technique and these limbs are repaired sequentially. Conclusion: This technique is simple and reproducible and it can be applied to partial tears and minimally retracted subscapularis tears.

Difficult Thoracic Pedicle Screw Placement in Adolescent Idiopathic Scoliosis

Retrospective radiographic and clinical consecutive case series. The objective of this study was to identify patients treated with posterior spinal fusion and pedicle screw instrumentation for adolescent idiopathic scoliosis (AIS) in whom it was not possible to place a planned pedicle screw, and describe the possible difficulties in screw placement. Despite the knowledge of anatomic characteristics of upper thoracic spine pedicles and considerable experience in thoracic pedicle screw placement, inserting pedicle screws in some patients with AIS may be difficult. We reviewed 96 patients with AIS in whom the intent was to use an all-screw construct in 2004. Placement of the pedicle screws was usually by the freehand method, with intraoperative fluoroscopy used as needed. If a screw could not be safely placed after multiple attempts, a down-going supralaminar or transverse process hook was placed. Medical records were reviewed and radiographs were measured by one of the authors. We identified 17 cases (18%) in which a hook had been placed. All cases had a major thoracic curve (Lenke 1, 2, and 3) and the single hook had always been placed at the most cephalad level of the construct on the patient's right side. The most common levels for hook placement were T3 and T4; these pedicles were noted to be sclerotic, narrow, and have a moderate amount of rotation on the preoperative posterior-anterior and side bending radiographs. Care should be exercised during pedicle screw instrumentation in the apical region of the proximal thoracic curve, whether structural or nonstructural, especially in the concavity. The preoperative radiographs may give helpful clues to intraoperative challenges of pedicle screw insertion at the uppermost level of instrumentation. Hook fixation was satisfactory in this scenario.

Posterior Vertebral Shortening With Screw and Hook Placement for Osteoporotic Vertebral Collapse With Paraplegia

Posterior vertebral shortening with pedicle screw and hook placement is a feasible treatment for delayed vertebral collapse with neurological deficits after osteoporotic spinal fracture.

Comparison of various pupil dilatation methods for phacoemulsification in eyes with a small pupil secondary to pseudoexfoliation

Purpose To compare 4 methods for intraoperative pupil dilatation in eyes with pseudoexfoliation syndrome and insufficient pupil size during phacoemulsification. Design Prospective, randomized, comparative, interventional case series. Participants Forty eyes of 40 patients with pseudoexfoliation and maximally dilated pupil size smaller than 3.5 mm. Intervention Mechanical pupil dilatation with iris-retractor hooks (group I), polymethyl methacrylate (PMMA) pupil dilator-ring (Morcher, Stuttgart, Germany) (group II), Beehler pupil dilator (group III), and bimanual stretching (group IV). Main outcome measures Performance (pupil size achieved), complications, and added surgical time. Results The mean pupil sizes achieved with the PMMA pupil-dilator ring, Beehler pupil dilator, and bimanual stretching were 5.9±0.6 mm, 5.5±0.8 mm, and 4.9±0.7 mm, respectively. A square-shaped pupil was achieved with iris-retractor hooks, and the mean size of the largest circle that can fit in this square was 5.6±0.6 mm. There were no statistically significant differences in the postdilatation pupil sizes between the 4 study groups ( P>0.05). Apart from self-limited intraoperative hemorrhage from pupil margin, iris sphincter rupture was the only observed complication related to mechanical pupil dilatation. This occurred in 4 eyes in groups I and III, 3 eyes in group IV, and 1 eye in group II ( P>0.05). The mean added surgical time for placement of iris-retractor hooks and for implantation of a PMMA pupil-dilator ring was 297±51 and 176±54 seconds, respectively. The additional time required for pupil dilatation with the Beehler pupil dilator and bimanual stretching was 65±8 and 55±10 seconds, respectively. The time needed for pupil dilatation in groups I and II is significantly longer than that in groups III and IV ( P<0.001). Conclusions All 4 methods used in this study were effective procedures for the mechanical dilatation of small pupils secondary to pseudoexfoliation syndrome. Iris-retractor hooks and the PMMA pupil-dilator ring are the most time-consuming techniques but have the advantage of a stable pupil size throughout the surgery. The PMMA pupil-dilator ring causes the least iris trauma. The Beehler pupil dilator and bimanual stretching technique were the least time-consuming methods for mechanical pupil dilatation.

Consistency analysis of authorization hook placement in the Linux security modules framework

We present a consistency analysis approach to assist the Linux community in verifying the correctness of authorization hook placement in the Linux Security Modules (LSM) framework. The LSM framework consists of a set of authorization hooks inserted into the Linux kernel to enable additional authorizations to be performed (e.g., for mandatory access control). When compared to system call interposition, authorization within the kernel has both security and performance advantages, but it is more difficult to verify that placement of the LSM hooks ensures that all the kernel's security-sensitive operations are authorized. Static analysis has been used previously to verified mediation (i.e., that some hook mediates access to a security-sensitive operation), but that work did not determine whether the necessary set of authorizations were checked. In this paper, we develop an approach to test the consistency of the relationships between security-sensitive operations and LSM hooks. The idea is that whenever a security-sensitive operation is performed as part of specifiable event, a particular set of LSM hooks must have mediated that operation. This work demonstrates that the number of events that impact consistency is manageable and that the notion of consistency is useful for verifying correctness. We describe our consistency approach for performing verification, the implementation of run-time tools that implement this approach, the anomalous situations found in an LSM-patched Linux 2.4.16 kernel, and an implementation of a static analysis version of this approach.

Use of the Anatomic Trajectory for Thoracic Pedicle Screw Salvage After Failure/Violation Using the Straight-Forward Technique: A Biomechanical Analysis

A biomechanical study of cadaver vertebrae to determine the feasibility of obtaining adequate thoracic pedicle screw fixation in a salvage situation. OBJECTIVE To investigate the ability to safely place a thoracic pedicle screw with adequate maximal insertional torque (MIT) using the anatomic trajectory (AT) (directed along the true anatomic axis of the pedicle) after purposeful failure/medial violation of the pedicle using the straight-forward trajectory (ST) (paralleling the vertebral endplate). Failure to place a pedicle screw at an intended segment of the thoracic spine may theoretically render the level uninstrumented, because pedicle hook placement may be unsafe and the transverse process may be fractured. An alternative pedicle screw insertion technique, if biomechanically sound in this situation, may present an excellent alternative for critical instrumentation levels. Fixed-head 5.0 mm stainless steel pedicle screws were placed using the ST and MIT was recorded after determination of bone mineral density (BMD) with dual-energy radiograph absorptiometry (DEXA) scanning. Purposeful screw malposition and critical pedicle wall failure were performed, followed by salvage placement of the screw using the AT. Insertional torque was recorded for each screw revolution with a digital torque wrench and MIT was again recorded to compare the MIT obtainable in the salvage situation. BMD for the vertebrae averaged 732 g/cm2 (620-884 g/cm2). The MIT for the straight-forward technique without pedicle violation was 2.61 +/- 0.19 (SE) inches per pound, whereas that of the salvage procedure after medial wall violation (AT) averaged 1.62 +/- 0.12 (SE) inches per pound. Therefore, the AT achieved 62% (P = 0.027) of the fixation strength (in terms of MIT) during salvage after failure/medial violation of the pedicle. MIT for both the ST* and AT trajectories correlated with both global BMD of the vertebrae (*P = 0.008; P = 0.004) and regional BMD of the vertebral body (*P = 0.044; P = 0.023). The AT achieved 62% (P = 0.027) of the MIT during salvage of a failed/violated pedicle. BMD correlated with both the initial and salvage techniques. The AT provides adequate fixation in a salvage situation and may be safely used to provide segmental fixation at critical levels.

Cricoid ring integrity: Implications for cricothyrotomy

Study objectives: The rapid 4-step technique for cricothyrotomy was originally described as making use of a single traction hook on the cricoid ring. However, it is possible that such hook placement could lead to damage of the cricoid ring. As an alternative, a double-hook device was developed to augment the rapid 4-step technique by dispersing forces applied to the cricoid ring. The objectives of this study were to compare the requisite forces for intubation and the structural tolerances of the cricoid ring between the single- and double-hook techniques. Methods: We randomized 56 human cadaver specimens to undergo either cricothyrotomy with intubation followed by cricoid ring breakage or cricoid ring breakage alone. We randomized those cadaver specimens undergoing cricothyrotomy with intubation with respect to the initial hook technique used and then crossed over to the alternate technique for repeat intubation and subsequent cricoid ring breakage. We performed all cricothyrotomies in a similar manner with a consistent technique. We measured the intubation and breakage forces for the single- and double-hook techniques and calculated 95% confidence intervals (CIs). Results: The mean force to intubate with the single-hook technique was 18 N (95% CI 14 to 22 N), and the mean force to intubate with the double-hook technique was 23 N (95% CI 17 to 29 N). There was a significant difference between the mean forces required to break the cricoid ring with the single-hook technique (54 N; 95% CI 47 to 62 N) versus with the double-hook technique (101 N; 95% CI 89 to 113 N; difference in means 47 [95% CI 34 to 60 N]). Conclusion: When applying the rapid 4-step technique for cricothyrotomy, the force required to intubate with either the single- or double-hook technique is small. The cricoid ring, however, tolerates significantly more force without breakage when the double-hook technique is used. [Ann Emerg Med. 2003;41:331-337.]

Performance of Barbed and Barbless Hooks in a Marine Recreational Fishery

Abstract We used an angling study to examine catch per unit effort (CPUE), bait loss, and total landings by anglers fishing with natural bait on barbed and barbless hooks in a nearshore marine sport fishery located in the Gulf of Mexico near St. Petersburg, Florida. Anglers fished half the day with a barbed hook and half the day with a barbless hook. We also recorded anatomical hook placement, severity of injury or bleeding, and hook extraction times for each landed fish. Bait loss, CPUE, and mean length of catch did not differ between gears, but anglers landed 22% more fish with barbed hooks. Loss of hooked fish was significantly higher with barbless hooks, and efficiency appeared to vary among species. Mean unhooking times were significantly shorter with barbless hooks. Anatomical hook placement did not differ between gears and most fish were hooked in the jaws. Bleeding did not differ between gears because bleeding was influenced strongly by hook placement, but barbless hooks reduced unhooking injuries...

Real time CT-fluoroscopy: diagnostic and therapeutic applications

The synergetic progression of CT technology and computer hardware has made ultrafast acquisition and image reconstruction possible. This has lead to the availability of CT interactive diagnosis and therapeutic procedures. Making use of our own material (337 intervention procedures during the last 17 months), we have compared our techniques and results to the recent literature data. One of the advantages of the biopsy technique is an improved sensitivity for neoplastic lesions, most certainly in cases of intrapulmonary lesions, surrounded by aerated tissue (now 94% compared to 87% in our previous study). A second advantage is the safety of the technique (only one major complication in our series). Fluid collection drainages, and more complex interventions like local injection of drugs, radio-frequency ablation, wire hook placement and ethanol injection were performed without complication. Yet another interesting feature is the shortening of the procedure time (reduced in average to an ‘in-room’ time of less than 30 min), which has definite economical implications. Furthermore it increases the patient’s comfort and safety, and extends the scope of outpatient procedures (80% outpatient procedures in our material). On the other side the radiation exposure can be raised as an issue, especially when we consider the operator’s hands. However, the described technique and the use of dedicated tools can alleviate the problem. As a conclusion, real time CT fluoroscopy has given a new input and broadens the scope of clinical indications of CT-guided diagnostic and therapeutic procedures.