Oblique Tunnels Research Articles

Biomechanical cyclic loading test of a synthetic ligament fixation system used for intra-articular stabilization of deficient canine stifles.

Background:Cranial cruciate ligament rupture (CCLr) is the most common cause of hind limb lameness in dogs. Currently, surgical management of CCLr is mostly performed using tibial osteotomy techniques to modify the biomechanical conformation of the affected stifle. These surgical techniques have a significant complication rate, associated with persistent instability of the stifle which may lead to chronic postoperative pain. Over the last decade, studies have been published on various techniques of anatomical caudal cruciate ligament reconstruction in veterinary practice, using physiological autografts or woven synthetic implants.Aim:The aim of this ex vivo biomechanical study is to investigate the ex vivo dynamic biomechanical behavior of a synthetic implant [ultrahigh molecular weight polyethylene (UHMWPE) implant] fixed with interference screws for the treatment of CCLr in dogs, according to a fatigue protocol (48 hours per test).Methods:Seven stifles from four skeletally mature canine cadavers were implanted with the synthetic implant. It was fixed with four interference screws inserted in transversal and oblique tunnels in both the distal femur and the proximal tibia. For each case, 100,000 cycles were performed at 0.58 Hz, with traction loads ranging from 100 to 210 N.Results:Neither screw-bone assembly rupture nor a pull-out issue was observed during the dynamic tests. Linear stiffness of the implants associated with a fixation system with four interference screws increased over time. The final displacement did not exceed 3 mm for five of the seven specimens. Five of the seven synthetic implants yielded to a lengthening in functional range (0–3 mm). Linear stiffness was homogeneous among samples, showing a strong dynamic strength of the interference screw-based fixations of the UHMWPE implant in the femoral and tibial bones.Conclusion:This study completes the existing literature on the biomechanical evaluation of passive stifle stabilization techniques with a testing protocol focused on cyclic loading at a given force level instead of driven by displacement. These biomechanical results should revive interest in intra-articular reconstruction after rupture of the CCLr in dogs.

Small, Short, Oblique Patellar Tunnels for Patellar Fixation Do Not Increase Fracture Risk or Complications in MPFL Reconstruction: A Retrospective Cohort Study.

Background:Large (4.5 mm) and/or transpatellar bone tunnels have been associated with patellar fracture after medial patellofemoral ligament (MPFL) reconstruction. To avoid this outcome, many surgeons now employ suture anchors to affix the MPFL graft to the patella.Purpose:To evaluate the risk of patellar fracture and other outcomes associated with smaller (3.2-mm), short, oblique patellar tunnels as compared with suture anchor fixation in MPFL reconstruction.Study Design:Cohort study; Level of evidence, 3.Methods:A single institution’s electronic medical record was queried for all patients undergoing MPFL reconstruction between March 2010 and December 2018. A chart review of operative reports was utilized to identify those who had undergone MPFL reconstruction. Patients undergoing revision MPFL reconstruction or reconstruction with fully transpatellar bone tunnels were excluded. The incidence of patellar fracture and outcomes were evaluated from chart review. The mean duration of follow-up was >2 years.Results:A total of 384 knees in 352 patients undergoing primary MPFL reconstruction were identified. Small (3.2-mm), short, oblique tunnels were used for patellar fixation in 215 cases, and suture anchors were utilized in 169 cases. The small, oblique tunnels and suture anchor techniques both resulted in a low incidence of patellar fracture, with rates of 0.47% and 0%, respectively. The use of suture anchors was associated with an increased risk of subluxation or dislocation compared with small, oblique tunnels (odds ratio, 3.98; P = .028). No significant difference was found in the need for revision MPFL reconstruction surgery with suture anchors (odds ratio, 1.925; P = .66).Conclusion:The use of small, oblique tunnels with hamstring autograft is a safe means of patellar fixation in MPFL reconstruction. The use of small, oblique tunnels for patellar fixation versus 2 suture anchors can result in material cost savings with no significantly increased risk for fracture as well as an overall reduction in complication rates.

Short Oblique Patellar Tunnels for Patellar Fixation Do Not Increase Fracture Risk in MPFL Reconstruction: A Retrospective Cohort Study

Objectives:The current standard of care for recurrent patellar instability is reconstruction of the medial patellofemoral ligament (MPFL), the primary soft tissue constraint to lateral subluxation of the patella. Historically, transpatellar bone tunnels have been associated with increased rates of patella fracture. To avoid this dreaded outcome, many surgeons now employ suture anchors to affix the MPFL graft to the patella. This study aims to evaluate the costs and outcomes associated with short oblique patella tunnels as compared to suture anchor fixation in MPFL reconstruction.Methods:A total of 467 knees in 419 patients undergoing MPFL reconstruction between 2011 and 2018 were included in the study. A single institution electronic medical record queried for all patients undergoing extra-articular ligament reconstruction using Current Procedural Technology codes 27422 and 27427. Chart review of operative reports was utilized to identify those who had undergone MPLF reconstruction. Patients undergoing revision MPFL reconstruction were excluded, as were patients for whom fully transpatellar bone tunnels were employed for patellar fixation. This left two groups: those for whom small, oblique tunnels (n = 277) and suture anchors (n = 190) for patellar fixation were compared. Implant pricing for the 3.2 mm drill bit, suture anchors, and allograft were obtained through publicly available databases and prior published research.Results:Short oblique tunnels showed no significant increase in risk of patellar fracture compared to suture anchors for patellar fixation (P = 1.00). Use of suture anchors was associated with an increased risk of subluxation or dislocation compared to small, oblique tunnels (OR = 3.34, P = 0.021). No significant difference in the need for revision MPFL reconstruction surgery was found (OR = 1.964, P = 0.45) [Table 1]. The cost difference between allo- and autograft in ligament reconstruction has been analyzed in multiple prior studies and found to be $1100. The 3.2mm drill bit used to create the tunnels cost $84 but is reusable, while the average cost of two suture anchors was $500, leading to a material cost savings of $1600 per case in which transpatellar tunnels were used for MPFL autograft fixation when compared to a suture anchor and allograft combination. Regardless of the graft choice, material cost savings exceeds $400 per case simply by conversion to short oblique tunnels rather than suture anchors.Conclusion:The use of small, oblique tunnels with hamstring autograft is a safe and cost effective method for patellar fixation in MPFL reconstruction. Value in healthcare is defined as quality divided by cost. As surgeons and institutions are increasingly judged not only by the quality of the care they provide, but also in its cost, employment of this high-value technique should be considered by surgeons performing MPFL reconstruction.

Physeal Disruption During ACL Reconstruction in Skeletally Immature Patients

Objectives:The purpose of this study was to radiographically assess differences in distal femoral physeal disruption between transtibial and independent femoral tunnel drilling techniques following ACL reconstruction in skeletally immature patients.Methods:A retrospective, matched comparative cohort study was performed of skeletally immature patients who underwent transphyseal ACL reconstruction between January 1, 2008 and March 31, 2011. All skeletally immature patients between ten and fifteen years old who underwent independent femoral tunnel drilling and had adequate baseline and post-operative radiographs were analyzed. These patients were matched with a transtibial technique cohort based on age and sex. Demographic characteristics and peri-operative metrics were collected. Radiographic measurements were recorded from pre-operative MRI and post-operative plain radiographs.Results:Twenty patients were analyzed. Between groups, there were significant differences between independent tunnel drilling and transtibial tunnel drilling in the estimated area of physeal disruption (1.64 cm2 vs. 0.74 cm2, P<0.001), femoral (32.1º vs. 72.8º, P<0.001) and tibial (50.1º vs. 60.5º, P=0.003) tunnel angles, medial/lateral location of the femoral tunnel (24.2 mm vs. 36.1 mm from lateral cortex, P=0.001), and distance from the lateral aspect of the distal femoral physis and the femoral tunnel exit (4.7 mm vs. 26.7 mm from the perichondrial ring, P<0.001), respectively. All patients who underwent femoral tunnel drilling at an angle of less than 25º from the transverse axis experienced a greater than 6% disruption of physeal area. There was a significant inverse correlation between femoral tunnel angle and estimated area of femoral physeal involvement (r=-0.8255, P=0.003).Conclusion:With femoral tunnel drilling techniques that create more oblique tunnels, the area of distal femoral physeal damage is larger, more eccentric and closer to the perichondrial ring. Since most studies noting the safety of transphyseal ACL reconstruction have utilized a vertical femoral tunnel, surgeons should be aware that if an independent femoral tunnel drilling technique is utilized during transphyseal ACL reconstruction, the physis is at greater risk when drilling at more horizontal angles. Angles greater than 25º from the transverse axis may safely create <6% physeal area damage.

Transphyseal ACL Reconstruction in Skeletally Immature Patients: Does Independent Femoral Tunnel Drilling Place the Physis at Greater Risk Compared to Transtibial Drilling?

The purpose of this study was to radiographically assess differences in physeal disruption between transtibial and independent tunnel drilling techniques following ACL reconstruction in skeletally immature patients. A retrospective, matched comparative cohort study was performed of skeletally immature patients who underwent transphyseal ACL reconstruction between January 1, 2008 and March 31, 2011. All skeletally immature patients between 10 and 15 years old who underwent independent femoral tunnel drilling and had adequate baseline and post-operative radiographs were analyzed. These patients were matched with a transtibial technique cohort based on age and sex. Demographic characteristics and peri-operative metrics were collected. Radiographic measurements were recorded from pre-operative MRI and post-operative plain radiographs. Twenty patients were analyzed. Between groups, there were significant differences in the estimated area of physeal disruption (1.64 cm2 vs. 0.74 cm2, P<0.001), femoral (32.1° vs. 72.8°, P<0.001) and tibial (50.1° vs. 60.5°, P=0.003) tunnel drill angles, medial/lateral location of the femoral tunnel (24.2 mm vs. 36.1 mm from lateral cortex, P=0.001), and distance from the lateral aspect of the distal femoral physis and the femoral tunnel exit (4.7mm vs. 26.7mm from the perichondrial ring, P<0.001). All patients who underwent femoral tunnel drilling at an angle of greater than 25° from the transverse axis experienced a <6% disruption of physeal area. With femoral tunnel drilling techniques that create more oblique tunnels, the area of physeal damage is larger, more eccentric and closer to the perichondrial ring. Since most studies noting the safety of transphyseal ACL reconstruction have utilized a vertical femoral tunnel, surgeons should be aware that if an independent femoral tunnel drilling technique is utilized during transphyseal ACL reconstruction, the physis is at greater risk when drilling at more horizontal angles. Angles greater than 25° from the transverse axis may safely create <6% physeal area damage.

Transphyseal ACL Reconstruction in Skeletally Immature Patients: Does Independent Femoral Tunnel Drilling Place the Physis at Greater Risk Compared With Transtibial Drilling?

Background:Most studies examining the safety and efficacy of transphyseal anterior cruciate ligament (ACL) reconstruction for skeletally immature patients utilize transtibial drilling. Independent femoral tunnel drilling may impart a different pattern of distal femoral physeal involvement.Purpose:To radiographically assess differences in distal femoral physeal disruption between transtibial and independent femoral tunnel drilling. We hypothesized that more oblique tunnels associated with independent drilling involve a significantly larger area of physeal disruption compared with vertically oriented tunnels.Study Design:Cross-sectional study; Level of evidence, 3.Methods:We analyzed skeletally immature patients aged between 10 and 15 years who underwent transphyseal ACL reconstruction utilizing an independent femoral tunnel drilling technique between January 1, 2008, and March 31, 2011. These patients were matched with a transtibial technique cohort based on age and sex. Radiographic measurements were recorded from preoperative magnetic resonance imaging and postoperative radiographs.Results:Ten patients in each group were analyzed. There were significant differences between independent drilling and transtibial drilling cohorts in the estimated area of physeal disruption (1.64 vs 0.74 cm2; P < .001), femoral tunnel angles (32.1° vs 72.8°; P < .001), and medial/lateral location of the femoral tunnel (24.2 vs 36.1 mm from lateral cortex; P = .001), respectively. There was a significant inverse correlation between femoral tunnel angle and estimated area of distal femoral physeal disruption (r = –0.8255, P = .003).Conclusion:Femoral tunnels created with an independent tunnel drilling technique disrupt a larger area of the distal femoral physis and create more eccentric tunnels compared with a transtibial technique.Clinical Relevance:As most studies noting the safety of transphyseal ACL reconstruction have utilized a central, vertical femoral tunnel, surgeons should be aware that if an independent femoral tunnel technique is utilized during transphyseal ACL reconstruction, more physeal tissue is at risk and tunnels are more eccentrically placed across the physis when drilling at more horizontal angles. Prior studies have shown that greater physeal involvement and eccentric tunnels may increase the risk of growth disturbance.

A comparison of Anterior Cruciate Ligament graft tunnel orientation: Anatomic vs. transtibial

BackgroundRecent Anterior Cruciate Ligament reconstruction techniques have emphasized reproducing the insertion sites of the native Anterior Cruciate Ligament. Anatomic techniques have shown improvements in biomechanical testing, but their superior results have not been shown clinically. The hypothesis of this study is that more oblique tunnels utilized in anatomic reconstructions cause asymmetric loading across the graft. MethodsSeven cadaver knees were tested in a knee simulator that performed a gait cycle and an anterior–posterior laxity test. Each knee underwent both reconstructions in random order utilizing the same Anterior Cruciate Ligament bone patellar tendon bone graft. Before reconstruction, the graft was split longitudinally and miniature force probes were inserted in the medial and lateral portions. FindingsDuring anterior–posterior laxity testing, the transtibial medial bundle averaged 74.8N compared to 87N for the anatomic. The lateral bundles averaged 146.2 and 158N respectively. Both reconstructions exhibited a similar ratio of force distribution between the bundles and there was no statistical difference. The average anterior–posterior motion for the intact knees was 10.8mm compared to 17.0mm after the Anterior Cruciate Ligament was sectioned. Anatomic reconstructions had an average of 14.0mm of laxity compared to 14.9mm for transtibial reconstructions (P<0.038). InterpretationGreater obliquity did not lead to an increase in asymmetry of graft loading. The failure of anatomic reconstructions to show clinical improvement over transtibial reconstructions is not due to oblique tunnels causing asymmetric graft loading.

Tensioned Reverse Abdominoplasty

Deformities of the upper portion of the abdominal wall can be difficult to solve, as in many cases abdominoplasties or mini-abdominoplasties lead to unsatisfactory results. Direct approaches to this region through inframammary incisions can be a good therapeutic option, once adequate patient selection has been performed and certain surgical principles are followed. This technique should be primarily indicated for patients complaining of skin laxity predominantly in the upper abdomen and for patients who will have such excess after liposuction. In patients who require resection of a large amount of tissue, a single, broad, U-shaped dissection should be used, associated with midline fascia plication, when required (group 1). In patients with a smaller amount of tissue to be resected, two oblique tunnels can be made toward the navel, with no incision unification at the midline, to provide less evident scars (group 2). Eighteen procedures were performed: 12 in group 1 and six in group 2. Patients and surgeons were satisfied with the results. Only minor complications occurred, and they did not result in definitive sequelae. The principle of progressive tension suture, previously utilized in conventional abdominoplasties, is now originally employed in reverse abdominoplasties as a continuous suture, enabling proper flap positioning, keeping the inframammary sulcus at its original position, and preventing tension on the resulting scar. Tensioned reverse abdominoplasty is an easily applicable technique that provides good results and should be considered in cases of abdominal laxity predominantly in the upper abdomen.

Burrow morphology and behavior of the mud shrimp Upogebia omissa (Decapoda:Thalassinidea:Upogebiidae)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 200:229-240 (2000) - doi:10.3354/meps200229 Burrow morphology and behavior of the mud shrimp Upogebia omissa (Decapoda: Thalassinidea: Upogebiidae) Vânia Rodrigues Coelho1,*, Roland Arthur Cooper2, Sérgio de Almeida Rodrigues3 1Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, CP: 11461, CEP: 05422-970, Brazil 2National Institutes of Health, Bethesda, Maryland 20892, USA 3Departamento de Ecologia Geral, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, CP: 11461, CEP: 05422-970, Brazil *Present address: Columbia University, Biosphere 2 Center, 32540 Biosphere Rd, Oracle, Arizona 85623, USA. E-mail: vcoelho@bio2.edu ABSTRACT: The burrow morphology, burrowing behavior and feeding mechanisms of the thalassinidean shrimp Upogebia omissa were studied. Twenty burrow casts were made in situ with epoxy resin, and an overall ŒY¹ shape was most frequently observed. Several burrows consisted of a single, oblique tunnel; burrow diameter was positively correlated with burrow length, maximum depth and distance between openings. Additionally, burrow length was positively associated with maximum depth, indicating that as burrow length increased burrow depth increased; i.e. burrows spread vertically rather than horizontally. Total sediment displacement by the burrows accounted for 2.6% of sediment to a depth of 30 cm. The sediment-water interface increased by 290% in areas containing burrows compared to areas without burrows. Solitary adults were trapped in 15 casts. Three casts were interconnected, but each burrow contained only 1 shrimp. Regression analysis revealed shrimp length to be positively correlated with burrow diameter and area. In aquaria, U. omissa displayed a dual feeding behavior: the shrimp filtered suspended particles, and also fed directly on the sediment. Filter-feeding occurred mainly within U-shaped tunnels, while deposit-feeding was observed in association with the oblique tunnels of the burrow. Although filter-feeding has been considered as the main trophic mode in upogebiids, we present evidence that U. omissa may have a more pronounced deposit-feeding behavior than described for other species of this group. Based on our findings, we suggest that current models on the functional morphology of burrows in relation to feeding should be used cautiously in inferring the trophic behavior of these shrimp. KEY WORDS: Shrimp · Burrow · Feeding · Upogebia · Decapoda · Thalassinidea Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 200. Publication date: July 14, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Development of the invaginated sleeve technique for continent cystostomies in dogs.

Two studies were undertaken in dogs to evaluate oblique tunnels through bladder walls lined by urothelium for use in continent cystostomies. In the first study, the tracts were lined completely by urothelium by 10 weeks, but tract calibre reduced considerably after stent removal and periluminal fibrosis was a prominent feature. In the second study a tubularised partial-thickness pedicle graft was invaginated through an oblique tunnel in the bladder wall, with the graft extending extravesically and then being wrapped in omentum. This technique provided complete urothelial covering by 2 weeks with much less periluminal fibrosis. In the 3 dogs catheterised daily up to 120 days, this technique afforded continence with generous tracts for catheterisation.