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PubMed2006

A new concept for the surgical anatomy of posterior deep complex fistulas: the posterior deep space and the septum of the ischiorectal fossa.

PURPOSE: This study was designed to investigate the pathophysiology of posterior complex fistula with reference to pelvic anatomy. METHODS: Three hundred twenty posterior complex fistula patients, operated on between 1995 and 2004, were examined. Thirty patients underwent preoperative magnetic resonance imaging. We also conducted two cadaver dissections. Posterior complex fistulas were classified by the extension forms of secondary ducts. RESULTS: The septum of the ischiorectal fossa, which comprises membranes between Alcock's canal and the anal canal, was newly identified intraoperatively and confirmed by magnetic resonance imaging and dissection. The ischiorectal fossa was separated by the septum of the ischiorectal fossa; the upper portion was the inferior levator space, and the lower was the clinical ischiorectal space. Primary lesions were found mainly in the posterior deep space (the anterior border was the internal sphincter, the superior border was the inferior surface of the puborectalis, the inferior and lateral borders were the anterior surfaces of the external sphincter; 97 percent). The primary opening was located in a posterior anal crypt (96 percent). The prevalence of posterior complex fistula limited to the posterior deep space, extending to the inferior levator space, the clinical ischiorectal space, or both, were 21, 14, 53, and 12 percent, respectively. The primary duct from a crypt proceeds diagonally into the internal sphincter to the posterior deep space. The posterior deep space is adjacent to the clinical ischiorectal space and the inferior levator space bordering on the external sphincter. If an abscess penetrates the sphincter from the posterior deep space, it can reach the clinical ischiorectal space and/or the inferior levator space. CONCLUSIONS: Recognition of the posterior deep space, the septum of the ischiorectal fossa, the inferior levator space, and the clinical ischiorectal space may be crucial for effective surgical management of posterior complex fistula.

Adult↗

PubMed2006

Surgical treatment for unstable low-grade isthmic spondylolisthesis in adults: a prospective controlled study of posterior instrumented fusion compared with combined anterior-posterior fusion.

BACKGROUND CONTEXT: The surgical treatment for low-grade isthmic spondylolisthesis in adults with intractable lumbar pain is usually spinal fusion. It has been postulated that anterior column reconstruction may be relatively advantageous in those patients with unstable slips. PURPOSE: To compare the early and medium term treatment efficacy of two common fusion techniques in isthmic spondylolisthesis. STUDY DESIGN/SETTING: Prospective controlled trial comparing single-level posterior-lateral instrumented fusion with combined anterior and posterior-lateral instrumented fusion in sequential matched cohorts of patients with radiographically unstable isthmic spondylolisthesis. OUTCOME MEASURES: Primary outcome measure of success was an Oswestry Disability Index (ODI)<or=20. Secondary outcome measures included patient determined minimum-acceptable outcome on four questionnaires: pain intensity (visual analog scale), ODI, medication intake, and work status. Radiographic outcome of fusion was determined by radiographic union and motion on flexion/extension X-rays. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for primary outcome of success for combined fusion compared with posterior fusion. METHODS: The study was conducted over a 6-year period. The first cohort of 50 consecutive patients was treated with a single-level instrumented posterior-lateral fusion; the second sequential cohort was treated with an anterior interbody fusion and the same posterior operation. Observations were made at baseline, 6 months, 1 year, and 2 years after surgery. Final radiographic assessment was made at 2 years after surgery. RESULTS: Baseline demographic and clinical factors were well-matched in the two cohorts. At 2 years, 46 posterior-only fusion subjects and 47 combined fusion subjects completed the full follow-up regimen. Outcomes were better by all measures at 6 months and 12 months in the anterior-posterior cohort. Comparing the primary outcome measure (ODI outcome<or=20) in the posterior versus the combined groups, success was achieved at 6 months in 11 versus 30 (RR=2.67, 95% CI 1.53, 4.67; p=.0001); at 1 year, 20 versus 34 (RR=1.66, 95% CI 1.14, 2.42; p<.005); and at 2 years, 29 versus 36 subjects (RR=1.21, 95% CI 0.93, 1.59; p=.14). At 6 months, 13 posterior-only and 25 combined group subjects had returned to work (RR 1.88, 95% CI 1.10, 3.21; p=.01). More patients achieved their preoperatively determined minimum-acceptable outcome at each time point. There were three nonunions in the posterior-alone cohort and one in the combined group. Serious complications and reoperations were similar in both groups. CONCLUSION: Outcomes up to 2 years were superior by clinically important differences after a combined anterior-posterior operation compared with posterior-alone surgery for unstable spondylolisthesis; however, between-group differences attenuated appreciably after 6 months. The apparent clinical and occupational benefits of combined fusion should be considered along with possible increases in minor complications and procedure-related costs.

Adult↗

PubMed1982

[Changes of posterior osseous elements in narrowing of antero-posterior diameters of the lumbar spinal canal].

Narrowing of the antero-posterior diameters of the foramen and its influence to the posterior osseous elements were studied on 585 dry vertebral bones of 117 human lumber specimens. 1. Narrowing of the antero-posterior diameter of the foramen progresses even after reaching adult age and continues thereafter. Close correlations were found between the antero-posterior diameters and the transverse diameters and between the antero-posterior diameters and the area. 2. Narrowing of the antero-posterior diameters of the foramen was due to hypertrophy of the inside of the L3 to L5 lamina, but it is also due to shortening of the pedicle or compression of the posterior elements of L1 and L2 level. 3. Together with narrowing of the antero-posterior diameters of the foramen due to developmental stenosis and due to advanced age, the articular facets move on toward the sagittal plane keeping 90 degree angle between the laminae, and medial edges of the superior articular facets approach to the mid-line and add the depth of the lateral recesses, but the antero-posterior diameters of the lateral recesses do not correlate with narrowing of the antero-posterior diameters of the foramen. 4. Changes of the posterior osseous elements related to the narrowing of the antero-posterior diameters of the foramen are significant at the lower lumbar vertebrae of the male. It is therefore concluded that developmental inclination, muscular activity and advanced age were factors influencing the spinal canal stenosis.

Adult↗

PubMed1999

Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine.

STUDY DESIGN: This is a retrospective study of the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament in the cervical spine. OBJECTIVES: To determine the morphologic limitations of the posterior approach in the management of ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Thirty-eight patients who underwent laminoplasty by midsagittal splitting for ossification of the posterior longitudinal ligament were reviewed. Fifteen patients were included in the noncontact group, in which the spinal cord was free of the ossified lesion after posterior decompression. Twenty-three patients were included in the contact group, in which the spinal cord was not free of the ossified lesion even after posterior decompression. METHODS: The preoperative sagittal alignment of the cervical spine and preoperative maximal thickness of ossification were compared between the two groups. In addition, the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament were investigated. RESULTS: The following factors were found to contribute significantly to contact between the spinal cord and ossification of the posterior longitudinal ligament after posterior decompression: 1) lordosis of less than 10 degrees or kyphosis in the preoperative sagittal alignment, and 2) preoperative maximal thickness of ossification of more than 7 mm. CONCLUSIONS: Patients who exhibit significant risk factors for continued contact of the spinal cord should be morphologically considered for anterior decompression.

Adult↗

PubMed1998

Posterior tilting of the tibial component decreases femoral rollback in posterior-substituting knee replacement: a computer simulation study.

Posterior tilting of the tibial component is thought to increase the range of motion in posterior cruciate-retaining total knee replacement, but its effect on implant motion in posterior cruciate-substituting total knee replacement is unknown. This issue has become of interest recently because manufacturers have introduced instrumentation that produces a posteriorly tilted tibial cut for both implant types. The purpose of this study was to investigate how motion of posterior cruciate-substituting total knee replacement is affected when the tibial component is installed with posterior tilt. Sagittal plane implant motions were predicted from prosthesis geometry with use of a computer simulation in which the femoral condyles were assumed to sit in the bottoms of the tibial condylar wells when the knee was in extension. Rollback of the femoral component was produced by a cam-spine mechanism at higher angles of flexion. The simulations revealed that even small degrees of posterior tilt reduced rollback by limiting the interaction between the cam and spine. Tilting the component posteriorly by 5 degrees caused the cam to contact the spine at a knee flexion angle that was 18 degrees higher than with the untilted component. The results suggest that posterior tilting of the tibial component in posterior cruciate-substituting knee replacement may not produce the same beneficial effects that have been reported for the tilting of tibial components in posterior cruciate-retaining knee replacement.

Arthroplasty, Replacement, Knee↗

PubMed2000

Posterior-inferior capsular shift for the treatment of recurrent, voluntary posterior subluxation of the shoulder.

BACKGROUND: The treatment of recurrent posterior instability of the shoulder, especially when it is associated with voluntary subluxation, remains controversial, and operative correction generally is not advised. METHODS: The results of operative correction of recurrent posterior subluxation in a consecutive series of twenty-six shoulders in twenty-four patients were reviewed. Eighteen shoulders were on the dominant side. The average age of the patients was twenty-four years (range, fifteen to thirty-three years). All of the patients had involuntary as well as voluntary posterior instability, but none had a psychiatric disorder. Only five patients had sustained a definite injury that had initiated the instability. Seven shoulders had had previous operations. A program of nonoperative treatment for a duration of at least three months had failed to control the symptoms in all patients. The twenty-six shoulders were treated with a posterior-inferior capsular shift procedure, which included repair of a so-called posterior Bankart lesion in seven shoulders. In addition, one of the shoulders had a posterior bone block and three shoulders (in two patients) had an osteotomy of the posterior part of the glenoid because of excessive glenoid retroversion. The outcome was assessed by means of a personal interview and a clinical examination, which included calculations of a score according to the system of Constant and Murley and the performance of the Simple Shoulder Test, and by means of a radiographic examination, with standardized radiographs and computerized tomography scanning. RESULTS: At an average of 7.6 years (range, 1.8 to 14.6 years) after the operation, the patients estimated that the function of the shoulder was an average of 86 percent of that of a normal shoulder. The average relative score according to the system of Constant and Murley was 91 percent. The subjective result was excellent for sixteen shoulders, good for eight, and fair for two. More than half of all of the patients were able to perform all activities of the Simple Shoulder Test, but eight patients (eight shoulders; 31 percent) still had discomfort at night. Five patients (21 percent) changed their profession because of the shoulder. All but one shoulder had a nearly normal active range of motion. The instability recurred in six (23 percent) of the twenty-six shoulders; three recurrences were in shoulders that had had a primary operation, and three were in shoulders that had had an operation on the posterior aspect of the shoulder before the index procedure. The instability did not recur in four shoulders that had had previous operations on the anterior aspect of the shoulder. The subjective shoulder value, which was the patient's estimation of the value of the affected shoulder as a percentage of that of an entirely normal shoulder, was significantly higher for the stable shoulders (91 percent) than for the unstable shoulders (72 percent) (p<0.05). The relative score according to the system of Constant and Murley was also higher for the stable shoulders (93 percent) than for the unstable shoulders (87 percent), but the difference was not found to be significant, with the numbers available. The joints were found to be well centered radiographically, and only six shoulders showed minimum signs of osteoarthritis. Computerized tomography scanning revealed an average glenoid retroversion of 3.2 degrees (range, 17 degrees of retroversion to 22 degrees of anteversion). When only the shoulders that had not had a posterior bone block or an osteotomy of the posterior aspect of the glenoid were considered, the average glenoid retroversion of those that had recurrent instability was 12.5 degrees, whereas it was only 6.2 degrees for those that remained stable (p<0.05). CONCLUSIONS: Overall, operative correction of voluntary posterior instability of the shoulder yielded very satisfactory intermediate-term clinical results. (ABSTRACT TRUNCATED)

Adolescent↗

PubMed2006

Effectiveness of posterior decompression for patients with ossification of the posterior longitudinal ligament in the thoracic spine: usefulness of the ossification-kyphosis angle on MRI.

STUDY DESIGN: A reliability study was conducted. OBJECTIVE: To report the utility of the ossification- kyphosis angle of a decompression site in the sagittal view of MRI in the preoperative evaluation of the effectiveness of posterior decompression for patients with ossification of the posterior longitudinal ligament in the thoracic spine. SUMMARY OF BACKGROUND DATA: In patients with ossification of the posterior longitudinal ligament, in the thoracic spine, posterior decompression may not always be effective for those with physiologic kyphosis; however, posterior decompression is sometimes useful for patients with multilevel lesions or with ossification of the ligamentum flavum. Therefore, it is necessary to evaluate the indications or limitations of posterior decompression before surgery. METHODS: The indications or limitations of posterior decompression for this disease were reviewed from the findings of intraoperative ultrasonography and various parameters on preoperative imaging in 22 patients with thoracic myelopathy. RESULTS: Thirteen patients had echo-free space and 9 patients had no echo-free space in intraoperative ultrasonography after posterior decompression. In the kyphosis angle of the decompression site and the configuration of the maximal prominent OPLL, there was no significant difference between the group with echo-free space and the group without echo-free space (P = 0.49, P = 0.55). On the other hand, the ossification-kyphosis angle of the decompression site was more than 23 degrees in all patients with no echo-free space (23 degrees -34 degrees , 28.2 degrees +/- 3.6 degrees ), and it was less than 23 degrees in all patients with echo-free space (10 degrees -23 degrees , 17.4 degrees +/- 4.1 degrees ). There was also significant difference between the groups statistically (P < 0.01, P = 1.50789E-06). In addition, in the occupation rate of the greatest prominence of the OPLL, there was statistically significant difference between the groups (P = 0.032). CONCLUSION: The ossification-kyphosis angle in the sagittal view of MRI has potential as an indicator of the effectiveness of posterior decompression in this disease. It is thought that there is a critical point of posterior decompression at nearly 23 degrees of the ossification-kyphosis angle of the decompression site. When the ossification-kyphosis angle is more than 20 degrees , the presence of echo free space should be carefully confirmed in intraoperative ultrasonography.

Adult↗

PubMedDate not supplied

Diagnosis of complete and partial posterior cruciate ligament ruptures. Stress radiography compared with KT-1000 arthrometer and posterior drawer testing.

Stress radiography was performed on 21 patients with unilateral posterior cruciate ligament tears: 10 complete and 11 partial. An 89-N posterior load was applied to the proximal tibia and a lateral radiograph was taken of each knee in 70 degrees of flexion. The relative amount of sagittal translation (involved minus noninvolved) was determined at both the medial and lateral tibial plateaus from the radiographic films. Arthrometric (KT-1000 arthrometer) and posterior drawer tests were also performed. The mean relative posterior translation averaged 12.2 +/- 3.7 mm for knees with complete tears. Arthrometer testing of the same knees showed 7.6 +/- 2.5 mm of increased translation, and posterior drawer testing showed 9.2 +/- 3.3 mm of increased dropback. Stress radiographic results were statistically similar to the electrogoniometric measurements in cadaveric knees. In knees with a partially torn posterior cruciate ligament, mean relative translation measured on stress radiographic was 5.6 +/- 1.5 mm, which was significantly different from that for knees with complete ruptures. The arthrometer and posterior drawer test data were not significantly different for knees with complete and partial tears. Stress radiography is superior to both the arthrometer and clinical posterior drawer testing for determining posterior cruciate ligament status. Eight millimeters of more of increased posterior translation on stress radiographs is indicative of complete rupture.

Adolescent↗

PubMed2004

Medial rectus pulley posterior fixation is as effective as scleral posterior fixation for acquired esotropia with a high AC/A ratio.

PURPOSE: To compare traditional medial rectus (MR) scleral posterior fixation versus MR pulley posterior fixation without scleral sutures for the treatment of acquired esotropia (ET) with a high accommodative convergence over accommodation (AC/A) ratio. DESIGN: Nonrandomized interventional case series. METHODS: Medical records were retrospectively reviewed for twenty-two patients who underwent bilateral MR posterior fixation for acquired ET with a high AC/A ratio, with or without associated MR recessions. The main outcome measure was the reduction in distance-near disparity created by MR scleral posterior fixation compared with MR pulley posterior fixation. RESULTS: Nine patients underwent MR scleral posterior fixation surgery, seven in combination with MR recessions for distance ET. Postoperatively, the distance-near disparity decreased an average of 11.8 prism diopters, stereoacuity improved in six patients, and eight patients no longer needed bifocals. Thirteen patients underwent MR pulley posterior fixation surgery, 10 in combination with MR recessions for distance ET. Postoperatively the distance-near disparity decreased an average of 14.4 prism diopters, stereoacuity improved in eight patients, and 12 patients no longer required bifocals. Statistically, the two procedures were equivalent. One patient in each group was undercorrected at near only, with the residual near ET controlled with bifocals. One patient who underwent MR pulley posterior fixation combined with large MR recessions was overcorrected at distance only. CONCLUSION: Traditional MR scleral posterior fixation and MR pulley posterior fixation are equally effective in treating acquired ET with a high AC/A ratio.

Accommodation, Ocular↗

PubMedDate not supplied

Pathomechanics of posterior sag of the tibia in posterior cruciate deficient knees. An experimental study.

This study was an investigation of the pathomechanics of posterior sag of the tibia in knees with posterior knee instability caused by PCL deficiency. By using fresh cadaver knees, the authors hoped to define the relationship of the posterior joint capsule and the medial and lateral collateral ligaments (MCL, LCL) with posterior knee instability in the PCL deficient knee. Thirty newtons of posterior stress were applied to the knees to simulate postoperative conditions. Roentgenographic methods were then used to evaluate posterior sag and change in the distance between the origin and insertion of the PCL. Strain gauges were used to measure the actual strain of the PCL and the collateral ligaments. The PCL, the posterior capsule, and the medial and lateral collateral ligaments were sequentially divided and the above measurements were then repeated in the same way, using 30 N of applied posterior stress. When only the PCL was cut, posterior sag and medial rotation of the tibia occurred with increasing severity as flexion increased. No sagging or rotation of the tibia was observed at full extension in the knees that had isolated PCL "injury". When the posterior capsule was sectioned, no significant changes were noted in the severity of the sag or the rotation. When the MCL or LCL was divided in a PCL deficient knee, greater sag occurred with flexion and a significant sag was observed even at full extension. The MCL "injury" was associated with increased medial rotation, whereas LCL "injuries" were associated with lateral rotation of the tibia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

Dynamic posterior shift test. An adjuvant in evaluation of posterior tibial subluxation.

The dynamic posterior shift test, a clinical method for evaluating both straight posterior instability and posterolateral rotatory instability, (PLRI), is a simple, dynamic, and reliable (reproducible) test that serves as an adjuvant to other clinical tests designed to evaluate an injury or insufficiency of posterior structures in the knee. The examiner maintains the hip at near 90 degrees of flexion to control rotation of the femur while slowly extending the knee passively. The hamstrings should be stretched to maintain their tightness. The tightened hamstrings assist gravity in subluxating the tibia posteriorly; they also provide dynamic axial loading to the joint as the knee is extended. In knees with posterior instability, the posteriorly subluxated tibia suddenly reduces as the knee joint nears full extension, and a jerk or "clunk" is felt by both the patient and the examiner. Thus, the patient's feeling of instability is reproduced by the test. We have used the dynamic posterior shift test for 5 years (as an adjuvant in our physical examination) to evaluate signs of posterior instability of the knee. Not only is the test reliable, but it is more definitive than other tests in evaluating straight posterior instability and PLRI. It is easy to perform and the results are reproducible. Because this test is dynamic rather than passive, it enhances the accuracy of evaluating posterior instability of the knee.

Biomechanical Phenomena↗

PubMed2006

brachyenteron is necessary for morphogenesis of the posterior gut but not for anteroposterior axial elongation from the posterior growth zone in the intermediate-germband cricket Gryllus bimaculatus.

In the long-germband insect Drosophila, all body segments and posterior terminal structures, including the posterior gut and anal pads, are specified at the blastoderm stage. In short- and intermediate-germband insects, however, posterior segments are sequentially produced from the posterior growth zone, a process resembling somitogenesis in vertebrates, and invagination of the posterior gut starts after anteroposterior (AP) axial elongation from the growth zone. The mechanisms underlying posterior segmentation and terminal patterning in these insects are poorly understood. In order to elucidate these mechanisms, we have investigated the roles of the Brachyury/brachyenteron (Bra/byn) homolog in the intermediate-germband cricket Gryllus bimaculatus. Loss-of-function analysis by RNA interference (RNAi) revealed that Gryllus byn (Gb'byn) is not required for AP axial elongation or normal segment formation, but is required for specification of the posterior gut. We also analyzed Gryllus caudal (Gb'cad) RNAi embryos using in situ hybridization with a Gb'byn probe, and found that Gb'cad is required for internalization of the posterior gut primordium, in addition to AP axial elongation. These results suggest that the functions of byn and cad in posterior terminal patterning are highly conserved in Gryllus and Drosophila despite their divergent posterior patterning. Moreover, because it is thought that the progressive growth of the AP axis from the growth zone, controlled by a genetic program involving Cdx/cad and Bra/byn, might be ancestral to bilaterians, our data suggest that the function of Bra/byn in this process might have been lost in insects.

Amino Acid Sequence↗

PubMed2005

[Anatomical study about the posterior coaxial portals via posterior tibial tendon sheath for ankle arthroscopy].

OBJECTIVE: To conduct the anatomical study about the posterior coaxial portals via posterior tibial tendon (PTT) sheath for ankle arthroscopy. METHODS: Coaxial portals were established in 20 ankles by K-wires which were left in place for distance measurement between them and the posterior nerves, tendons and vessels. Ankle arthroscopy was performed in 5 fresh ankles using 2.7 mm 300 arthroscopy with the same portals as mentioned above. The maximum visible scope were recorded and the distance between the arthroscopy and the posterior nerves, tendons and vessels was also measured. RESULTS: The medial portal was located 5 - 12 mm (average, 8 mm) above the tip of medial malleolus, and the lateral portal was located 8 - 24 mm (average, 15 mm) above the tip of lateral malleolus. The coaxial portals, which traversed the PTT sheath and passed posterior to the fibular, not only separated the arthroscopy and instrument from the posterior nerves, tendons and vessels by posterior capsule but also enlarged their distance. The medial and lateral malleolus articular gap, the posterior capsule could be viewed by these portals with as much as 1/2 - 2/3 posterior articular surface of talus. Not only the tibiotalar articular gap but also the dynamic movement between the mortise and the talus were clearly observed. Arthroscopic operation could be performed by instrument through the posterolateral portal. CONCLUSIONS: The posterior coaxial portals via PTT sheath for ankle arthroscopy have such advantages as easy maneuverability, superior safety, clear vision and larger operation field under arthroscopy.

Ankle Joint↗

PubMed2005

Posterior capsulorrhaphy for treatment of recurrent posterior glenohumeral instability.

The surgical treatment of recurrent posterior shoulder instability via a posterior approach has had a variable degree of success reported in the literature with recurrence rates ranging between 8% and 45%. The purpose of this study was to review the results of posterior capsulorrhaphy in a consecutive series of patients with recurrent posterior instability. Seventeen consecutive patients underwent operative management for posterior glenohumeral instability. The dominant shoulder was involved in ten patients. All patients were male with an average age of 28.1 years (range: 16 to 54 years). Ten patients had sustained a specific injury which precipitated the instability. Six patients reported dislocations requiring formal closed reduction maneuvers; the remainder described episodes of recurrent subluxation with spontaneous reduction. All patients underwent a posterior capsulorrhaphy using an infraspinatus splitting approach. Eight shoulders required repair of a posterior capsulolabral detachment. In addition, one patient required augmentation with a posterior bone block for significant glenoid rim deficiency. Outcome was assessed by personal interview, clinical assessment, and standardized radiographs. At an average follow-up of 3.9 years (range: 1.8 to 10.8 years) patients estimated their overall shoulder function to be 81% of the contralateral unaffected shoulder. The subjective result was excellent for eight patients, good for five patients, fair in two patients, and poor in two patients. One of the poor outcomes was in a patient with glenohumeral degenerative changes at the index procedure which progressed and eventually required a total shoulder arthroplasty. The other poor result was in a patient found to have a full-thickness rotator cuff tear 10.6 years after the index procedure. Two patients (12%) had recurrence of their instability. Both of these patients sustained a significant re-injury which precipitated their symptoms. Five patients complained of occasional night pain at the time of their last follow-up examination. Only one patient (who was re-injured) had to change professions as a result of shoulder symptoms. Posterior capsulorrhaphy for treatment of isolated posterior glenohumeral instability yields satisfactory clinical results. Recurrent instability in this series was associated with a specific re-injury and did not appear to increase with longer follow-up.

Adolescent↗

PubMedDate not supplied

Posterior approaches in the management of cervical spondylosis and ossification of the posterior longitudinal ligament.

BACKGROUND: If the cervical lordotic curvature has been well preserved, spondylostenosis or ossification of the posterior longitudinal ligament, with or without instability, may be approached posteriorly in selected older patients (over 65 years of age). Posterior surgical alternatives include the laminectomy with or without fusion, or laminoplasty. However, in younger patients or in geriatric patients with predominantly anterior disease with kyphosis, direct anterior surgical procedures yield better results. METHODS: Laminectomy with medial facetectomy and foraminotomy is classically performed in cases in which stability is preserved. However, posterior stabilization using either facet wiring or lateral mass fusion may be warranted. Although some consider the "open door" laminoplasty a reasonable alternative for dorsal decompression, limitations include restricted access to the hinged side, a potential for "closing of the door," and it does not offer a "real" fusion. RESULTS: Postoperative neurologic improvement may approximate an 85% incidence of good to excellent results. However, where a posterior decompression has been chosen, particularly in younger individuals with or without a lordotic curvature, or in older patients with kyphosis, they will fail to significantly improve, and will be susceptible to early neurologic deterioration. CONCLUSIONS: Posterior approaches to cervical disease may be successful in geriatric individuals in whom the cervical lordotic curvature has been well preserved. However, it is inappropriate for either older or younger patients with predominantly anterior disease, for whom direct anterior decompression with or without posterior stabilization is indicated. In those patients with significant ventral ossification of the posterior longitudinal ligament (OPLL), direct anterior resection will result in improved neurologic outcomes, whereas posterior decompression will fail to achieve a similar degree of neurologic recovery. Furthermore, dorsal decompression of OPLL may promote a more rapid progression of OPLL growth and concomitant neurologic deterioration.

Adult↗

PubMed2003

Posterior "back and forth" approach in arthroscopic surgery on the posterior knee compartments.

We report the feasibility, indications, and usefulness of an arthroscopic approach to the posterior knee compartments. We developed an arthroscopic approach to the posterior knee compartment involving use of a posteromedial portal and a posterolateral portal opposite each other. Each posterior portal is used in alternation for the arthroscope and instruments. The posterior portals are established using an original "back and forth" technique. The feasibility of the technique was evaluated on a cadaver. It allowed us to define safety rules to protect the vessels and nerves that course through the popliteal fossa. The approach provided a broader field of view compared with classical techniques. After removal of the septum dividing the posterior compartment, the synovial fold enclosing the posterior cruciate ligament and lining the upper and posterior parts of the posterior capsule was readily accessed, suggesting that this approach may be particularly valuable for total synovectomy. This was confirmed in 6 patients with villonodular synovitis, in whom the new approach was used in combination with arthroscopic anterior synovectomy. This technique allows removal of parts of the synovium that are difficult to access through conventional arthroscopic approaches. For total synovectomy, it can be used as an alternative to open posterior synovectomy, in combination with arthroscopic anterior synovectomy.

Arthroscopy↗

PubMed2005

Posterior cruciate ligament recess and normal posterior capsular insertional anatomy: MR imaging of cadaveric knees.

PURPOSE: To analyze the normal pattern of fluid accumulation adjacent to the posterior cruciate ligament and anatomic variations of joint capsule insertion sites in the posterosuperior corner of the human knee by using magnetic resonance (MR) imaging in cadaveric specimens. MATERIALS AND METHODS: Fourteen fresh cadaveric knees (obtained and used according to institutional guidelines, with informed consent from relatives of the deceased) from 11 men and three women (six left knees, eight right knees; age range, 70-82 years at time of death; mean age, 76 years +/- 4.4 [standard deviation]) were studied with high-spatial-resolution MR imaging performed before and after intraarticular injection of 35-45 mL gadopentetate dimeglumine. MR images were evaluated by two readers in consensus, with emphasis on location of fluid posterior to the posterior cruciate ligament, communication of that fluid with the medial or lateral compartment of the knee, and the relation of fluid to surrounding structures. Readers also were asked to measure, in the sagittal plane, the distance between the posterior capsular insertion sites and the femoral physeal scar. For anatomic analysis, cadaveric specimens were sectioned in 3-mm-thick slices in the sagittal plane that approximated the sections acquired at MR imaging. RESULTS: In all 14 cadaveric specimens, MR arthrographic images showed a fluid collection behind the posterior cruciate ligament (in the posterior cruciate ligament recess), a finding not evident on images obtained prior to contrast material injection. The recess was distended during flexion, and it communicated only with the medial femorotibial compartment in all cases. Posterior to the posterior cruciate ligament recess, a fat pad was observed in all specimens. Incomplete joint capsule was seen behind the fat pad in seven specimens. Joint capsule insertion was at the level of the femoral physeal scar or between it and a point 15 mm above it. CONCLUSION: The posterior cruciate ligament recess has specific characteristics that allow its identification: communication with the medial compartment of the knee and absence of the adjacent joint capsule.

Aged↗

PubMed1997

A biomechanical study of replacement of the posterior cruciate ligament with a graft. Part 1: Isometry, pre-tension of the graft, and anterior-posterior laxity.

UNLABELLED: Twelve fresh-frozen knee specimens from cadavera were subjected to anterior-posterior laxity testing with 200 newtons of force applied to the tibia; testing was performed before and after a femoral load-cell was connected to a mechanically isolated cylindrical cap of subchondral femoral bone containing the femoral origin of the posterior cruciate ligament. The posterior cruciate ligament then was removed, the proximal end of a thin trial isometer wire was attached to one of four points designated on the femur, and displacement of the distal end of the wire relative to the tibia was measured over a 120-degree range of motion. The potted end of a ten-millimeter-wide bone-patellar ligament-bone graft was centered over the femoral origin of the ligament and attached to the femoral load-cell. Isometry measurements were repeated with the wire attached to the bone block of the free end of the graft in the tibial tunnel. Force was recorded at the load-cell (representing force in the intra-articular portion of the graft) as pre-tension was applied, with use of a calibrated spring-scale, to the tibial end of the graft. A laxity-matched pre-tension of the graft was determined such that the anterior-posterior laxity of the reconstructed knee at 90 degrees of flexion was within one millimeter of the laxity that was measured after installation of the load-cell. Anterior-posterior testing was repeated after insertion of the graft at the laxity-matched pre-tension. The least amount of change in the relative displacement of the trial wire over the 120-degree range of flexion occurred when the wire was attached to the proximal point on the femur (a point on the proximal margin of the femoral origin of the posterior cruciate ligament, midway between the anterior and posterior borders of the ligament). The greatest change in the relative displacement was associated with the anterior point (a point on the anterior margin of the femoral origin of the ligament, midway between the proximal and distal borders). The mean relative displacements of the trial wire when it was attached to a point at the center of the femoral origin of the ligament were not significantly different from the corresponding mean displacements of the distal end of the graft when the proximal end of the graft was centered at this point. At 90 degrees of flexion, the force recorded by the load-cell averaged 64 to 74 per cent of the force applied to the tibial end of the graft. The laxity-matched pre-tension of the graft at 90 degrees of flexion (as recorded by the load-cell) ranged from six to 100 newtons (mean and standard deviation, 43.0 +/- 33.4 newtons). With the numbers available, the mean laxities after insertion of the graft were not significantly different, at any angle of flexion, from the corresponding mean values after installation of the load-cell. CLINICAL RELEVANCE: Isometer readings from a trial wire attached to a point on the femur provided an accurate indication of the change in the length of a graft subsequently centered at that point. Anteriorly placed femoral tunnels should be avoided, as the isometer readings indicated increased tension, with flexion of the knee, in a graft placed in this region. The force in the intra-articular portion of the graft was always less than the force applied to the bone block in the tibial tunnel. Therefore, the femoral end of the graft should be tensioned to avoid frictional losses from the severe bend in the graft as it passes over the posterior tibial plateau. With correct pre-tensioning of a graft, normal anterior-posterior laxity at 0 to 90 degrees of flexion can be restored. However, because of the considerable range in the laxity-matched pre-tensions, we recommend that the pre-tension be greater than forty-three newtons for all patients to ensure that normal laxity is restored.

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