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Biomedical subjects

M L Routt

Publications and source records attributed to M L Routt.

At least 37 records · Page 2Linked to original sources
PubMed1996

Retropubic vascular hazards of the ilioinguinal exposure: a cadaveric and clinical study.

In the course of ilioinguinal exposure, significant bleeding can occur from anastomotic vascular channels along the posterior aspect of the superior public ramus. A cadaveric study was undertaken to quantify and qualify these communicating vascular systems. We made bilateral ilioinguinal exposures on 40 cadavers. All vessels > 2 mm in diameter, connecting the obturator system with a more superficial system, were singled out and their courses recorded. Fifty-eight of 79 sides (73%) had at least one large-diameter communicating vascular channel along the posterior aspect of the superior pubic ramus. In 47 of the 79 exposures (59%) communicating veins were noted. Arterial channels were identified in 34 exposures (43%). A prospective clinical study was also performed. Thirty-eight consecutive patients with displaced acetabular fractures were treated surgically using ilioinguinal exposures. Fourteen of the patients (37%) had anastomotic vessels. This study confirms the variability of the retropubic vascular system.

Acetabulum↗
PubMed1996

Radiographic recognition of the sacral alar slope for optimal placement of iliosacral screws: a cadaveric and clinical study.

Malpositioning of iliosacral screws happens more often when common variations in the morphology of the upper sacral segments are unrecognized. Radiological-anatomic correlations of sacral anatomy were studied in 10 fresh-frozen cadaveric pelvises without evidence of skeletal disease, obtained from six male and four female donors. Eighty consecutive patients with complicated pelvic fractures treated operatively by the same surgeon using percutaneously placed iliosacral screws were evaluated. Variations in the sacral alar anatomy and slope found in upper sacral segmentation anomalies are common. Surgically important and predictable abnormal morphological patterns can be easily identified using pelvic outlet and lateral sacral plain radiographs along with computed tomographic scans. On the true lateral projections, the iliac cortical density adjacent to the sacroiliac joint parallels the sacral alar slope and is almost always caudal and posterior to it; it delineates the anterior extent of the "safe zone" for iliosacral screw insertion. Thus, the lateral sacral image provides the surgeon with a better understanding of the sacral alar slope and can help prevent iliosacral screw placement errors. The lateral sacral image should always be used intraoperatively with the inlet and outlet images to guide iliosacral screw placement.

Adolescent↗
PubMed1996

Internal fixation in pelvic fractures and primary repairs of associated genitourinary disruptions: a team approach.

Associated urological and orthopedic injuries of the pelvic ring are complex with numerous potential complications. These patients are treated optimally using a team approach. The combined expertise is not only helpful initially when managing these difficult patients, but also later as problems develop. This study describes a treatment protocol and reports the early results of 23 patients with unstable pelvic fractures and associated bladder or urethral disruptions, or both, treated surgically with open reduction and internal fixation of the anterior pelvic ring injuries at the same anesthetic and using the same surgical exposure as the urethral realignments or bladder repairs or both. Early complications occurred in four patients (17%): one patient sustained a fifth lumbar nerve injury caused by the pelvic reduction procedure, and three patients had anterior pelvic internal fixation failures. Late complications occurred in eight patients (35%). There was one deep wound infection (4.3%) that presented 6 weeks after injury. Late urological complications occurred in seven patients (30%). Four of the nine male patients with urethral disruptions had urethral stricture after their primary urethral realignments (44%). Three of the 18 male patients admitted to impotence (16.7%). One of the three had a residual thoracic paraplegia caused by a burst fracture. One of the five female patients had urinary incontinence and required a bladder suspension operation to restore normal function (20%). A low infection rate can be expected despite the use of internal fixation. Early urethral "indirect" realignments avoid more difficult delayed open repairs; however, late urological complication rates are still high. Early "direct" bladder repairs are easily performed at the time of anterior pelvic open reduction and internal fixation. Suprapubic tubes are not necessary to adequately divert the urine when large diameter urethral catheters are used in these patients.

Adolescent↗
PubMed1996

Evaluation of new plate designs for symphysis pubis internal fixation.

The purpose of this study was to evaluate and compare biplanar and other newly designed plates used for pubic symphysis internal fixation to other standard plates. Our data demonstrate that neither of the newly designed symphyseal plates, curved (Zimmer four-hole plate with either two or four 4.5-mm cortical screws) nor the biplanar (Zimmer six-hole plate with four 4.5-mm cortical screws in one plane and two 4.5-mm cortical screws in another) significantly reduce motion more than the other plates tested (Synthes two-hole 4.5-mm dynamic compression plate with two 6.5-mm cancellous screws and six-hole 3.5-mm reconstruction plate with four 3.5-mm cortical screws). All of the plate constructs were able to restore motion to nearly that of the intact symphysis pubis and sacroiliac joint. In summary, using the anteroposterior compression disruption pattern and model, the disrupted symphysis does gap under load but has no effect on sacroiliac joint gapping. It does permit increase in relative flexion angles between the wings of the pelvis. All of the plate systems tested restore normal gap motion at the symphysis and normal sacroiliac joint flexion.

Bone Density↗
PubMed1996

Internal fixation of pelvic ring disruptions.

The internal fixation of pelvic ring fractures and dislocations has become more popular recently. Aggressive resuscitation of the injured patient includes pelvic stabilization and improves survival rates. Pelvic surgical exposures as well as the skeletal anatomy become more familiar as the orthopaedic surgeon gains experience in treating these difficult patients. Recent radiographic techniques for pelvic imaging facilitate comprehensive preoperative planning and intraoperative decision-making for pelvic injuries. Improved outcomes are expected as treatment is individualized for each patient.

Adolescent↗
PubMed1995

The retrograde medullary superior pubic ramus screw for the treatment of anterior pelvic ring disruptions: a new technique.

Retrograde medullary screws were used in 26 patients with unstable pelvic ring injuries to stabilize the superior public ramus fractures. The posterior pelvic ring fractures and dislocations were fixed with iliosacral screws. The retrograde screws were inserted after closed manipulative reductions of the superior pubic ramus fractures in 15 patients and after open reduction in nine patients. We were unable to insert the screw in two patients due to anatomical variations. One screw was misplaced superior to the pubic ramus and noted only on the postoperative computed tomography scan. Another patient experienced symptomatic screw disengagement that required reoperation. All fractures healed and no infections developed. Blood loss was minimal for the percutaneous procedures. The technique provides stability to the anterior pelvic ring without the need for extensile surgical exposures. The complications of both anterior pelvic external fixation and plating are avoided, yet this technique has its own potential problems. The procedure is described in detail, and the early results and complications are documented in our first 26 patients.

Acetabulum↗
PubMed1995

Early results of percutaneous iliosacral screws placed with the patient in the supine position.

The operative management of pelvic ring fractures and dislocations is difficult. Posterior pelvic ring disruptions are often associated with severe soft-tissue injuries and high infection rates. Percutaneous iliosacral screw fixation of the posterior pelvis has become popular with improved fluoroscopic imaging techniques. The percutaneous iliosacral screw technique after closed reduction of the posterior pelvic disruption minimally violates the soft-tissue envelope and should diminish both the operative blood loss and infection rate. The early results and complications are documented in our first 68 patients.

Adolescent↗
PubMed1995

Retrograde nailing of femoral shaft fractures.

OBJECTIVE: The purpose of the study was to define the outcome following retrograde nailing of the femoral shaft. DESIGN: Retrospective clinical study. MATERIALS AND METHODS: Seventeen retrograde intramedullary nailings of the femur were performed in 16 patients for management of complex orthopedic trauma. Thirteen patients were followed for an average of 22.8 months (range from 9 to 72 months). The indications for retrograde nailing were an ipsilateral femoral neck and shaft fracture in eight cases, knee disarticulation or long above knee amputation associated with a femoral shaft fracture in five cases, traumatic arthrotomy of the knee ipsilateral to a shaft fracture in two cases, one case of a shaft fracture ipsilateral to an acetabular fracture that required an extensile exposure, and one case of a femoral nonunion with a knee contracture. In fourteen of the seventeen cases the femur fracture was open including two grade III C injuries. MEASUREMENTS AND MAIN RESULTS: Two patients died in the early postoperative period due to the severity of the initial trauma and one patient was lost to follow-up. The results were generally poor and postoperative complications were common. There were five nonunions in the group, one which required revision to an above knee amputation for an infected nonunion following a grade III open femur fracture. The average range of motion of the knee was 3 degrees to 110 degrees, and two patients had an extensor lag of 5 degrees or more. Six patients underwent removal of hardware through a second arthrotomy with no significant loss of knee function related to the second procedure. CONCLUSIONS: The authors concluded that the high complication rate and poor results were related to the severity of the initial injury. An intercondylar starting can be used in properly selected cases with minimal effect on knee function.

Adult↗
PubMed1995

The acetabular T-type fracture. A biomechanical evaluation of internal fixation.

The purpose of this study was to evaluate the stability of different types of internal fixation requiring anterior, posterior, or combined surgical approaches for the T-type acetabular fracture. Eight specimens were loaded 25 times in a cyclic manner to 150 N for each type of fixation construct evaluated. The model attempted to range the hip through an arc of motion anticipated in the limited activities expected after surgery. Strain gauges were placed on the 3 fracture planes of the T-type fracture. These gauges measured displacements. Internal fixation consisted of a single anterior column plate, compared with a single posterior column plate, compared with simultaneous placement of both anterior column and posterior column plates. The differences in displacements measured between the 3 types of fixation at each of the 3 fracture sites were not statistically significant. In evaluating motion at the anterior fracture line, the anterior plate made the largest contribution to stability, although this result was not statistically significant. The posterior plate similarly contributed most to posterior fracture stability, although again not statistically significant. Each of the 3 fixations controlled the inferior fracture line motions in a comparable manner.

Acetabulum↗
PubMed1995

Anterior versus posterior provisional fixation in the unstable pelvis. A biomechanical comparison.

Pelvic ring injuries with associated hemorrhage often require provisional fixation to achieve tamponade. Biomechanics information regarding these provisional fixators is unknown. Six fresh-frozen cadaveric pelvic specimens were physiologically loaded, first intact and then after each of the following modifications: disrupted--unilateral superior and inferior rami osteotomies, ipsilateral anterior and posterior sacroiliac joint, and sacrospinous and sacrotuberous ligament disruption; disrupted and with placement of a Ganz pelvic resuscitation clamp; and disrupted and with placement of a simple anterior 2-bar external fixator. This injury resulted in significant motion at the disrupted rami and the injured sacroiliac joint, compared with the intact pelvic specimen. Motions at the superior ramus and injured sacroiliac joints were significantly (p < 0.05) greater than the intact specimen, with both the external fixator and the Ganz clamp. Motions at the superior ramus and injured sacroiliac joints were not significantly (p < 0.05) different when comparing the Ganz clamp to the external fixator. However, the anterior external fixator decreased motion to a greater degree at the disrupted rami, whereas the Ganz clamp decreased motion to a greater degree at the disrupted sacroiliac joint.

Aged↗
PubMed1995

A rational approach to pelvic trauma. Resuscitation and early definitive stabilization.

The patient with polytrauma and an unstable pelvic ring injury is a treatment challenge. The orthopaedic surgeon should be involved in the care when the patient is brought into the hospital. Rapid pelvic ring stability should diminish pelvic hemorrhage. Early treatment decisions have significant impact on subsequent options. A team approach using open communication among the various subspecialties allows coordinated care and optimizes outcome. Early, definitive pelvic internal fixation is difficult yet beneficial.

Adolescent↗
PubMed1994

Extramedullary skeletal traction for intramedullary femoral nailing.

The through-and-through forms of femoral skeletal traction that are often used during intramedullary nailing for femur fractures can present two problems: (a) impingement with the intramedullary nail, requiring repositioning of the traction pin intraoperatively under radiographic control, to a position that may not optimally control the fracture; and (b) the risk of contaminating the intramedullary canal that will soon contain the metallic fixation device, especially when placed in the emergency room or at the bedside. Two new forms of extramedullary skeletal femoral traction are presented. The pullout strength and optimal positioning of these devices on the distal femur were evaluated. The first form of extramedullary traction evaluated was the large AO/ASIF pinless clamp. The second form of extramedullary traction, the extramedullary skeletal clamp, was based on a modification of the Gardner-Wells tong. These two forms of skeletal traction were compared with standard tensioned Kirschner wire (K-wire) through-and-through traction. Six fresh-frozen distal femora from donors (average age 29 years) were used to test the three femoral traction devices. Five of these specimens were skeletally mature. A total of 38 pullout tests were conducted. The pullout strength of the tested devices was in the following descending order: (a) tensioned K-wire; (b) extramedullary skeletal clamp (in the optimal metadiaphyseal position, 77% the strength of the K-wire); and (c) large ASIF pinless clamp (in the optimal metaphyseal position, 46% the strength of the K-wire). The mode of failure for each device was cut out through or from the bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Fracture-dislocation of the shoulder in a child: case report.

This is a case of an 11-year old girl with a delayed diagnosis of a shoulder fracture-dislocation. Shoulder dislocations are rare, and proximal humerus fractures are uncommon. A fracture-dislocation in a child is, to our knowledge, as yet unrepresented in the English-language literature. The child's injury resolved without recurrence.

Bone Remodeling↗
PubMed1994

Internal fixation of the unstable anterior pelvic ring: a biomechanical comparison of standard plating techniques and the retrograde medullary superior pubic ramus screw.

The purpose of this study was to evaluate pubic ramus fracture fixation. This biomechanical evaluation compared standard plating techniques with retrograde medullary screw fixation of a superior pubic ramus fracture in a pelvic fracture model. Six fresh-frozen, cadaveric pelvic specimens with a mean age of 79 years were harvested. These specimens were physiologically loaded according to the following modifications and instrumentations: (a) intact; (b) an APC-II unstable pelvic injury, specifically, unilateral superior and inferior rami osteotomies combined with ipsilateral anterior sacroiliac (SI) joint, sacrospinous, and sacrotuberous ligamentous disruptions, without fixation; (c) disrupted as in (b) but fixed anteriorly with a 10-hole 3.5-mm reconstruction plate contoured to the superior ramus and secured with four 3.5-mm cortical screws; (d) disrupted as in (b) but fixed anteriorly with a 10-hole 3.5-mm reconstruction plate contoured to the superior ramus and secured with six 3.5-mm cortical screws; (e) disrupted as in (b) but fixed anteriorly with a 4.5-mm retrograde medullary superior pubic ramus cortical screw 80 mm long (medial to the hip joint); and (f) disrupted as in (b) but fixed anteriorly with a 4.5-mm retrograde medullary superior pubic ramus cortical screw 130 mm long that was extraarticular and engaged the lateral iliac cortex cephalad to the ipsilateral hip joint. The posterior disruptions of the pelvic ring were not fixed. The APC-II injury created in this study resulted in significant (p < 0.05) motion at the disrupted rami and the injured SI joint, compared with the intact pelvic specimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Box plate fixation of the symphysis pubis: biomechanical evaluation of a new technique.

The purpose of this study was to compare common techniques of pubic symphyseal fixation with a new method, the "box plate," for fractures of the pelvis where the bone is osteopenic. This symphyseal fixation construct consists of two, two-hole, 4.5-mm narrow dynamic compression plates (DCP) oriented parallel to one another. One plate is recessed within the symphysis, and the other is located on the pubic tubercles. The plates are interlocked using two 6.5-mm fully threaded screws, forming a box-like construct. To determine the mechanical properties of this construct, five fresh, cadaveric pelvic specimens with a mean age of 75 years were harvested. The femora of each specimen were potted into containers and fixed to the base of a materials testing machine. The pelvis was constrained from rotating about the hip joints by anterior and posterior restraints. A vertical compressive load was applied through the lumbar spine. Force to a magnitude of 1,000 N was applied through three cycles. Gapping motions at the symphysis pubis (SP) and the sacroiliac (SI) joints, and flexion-extension of the sacrum with respect to the ilia were measured under the following conditions: (a) intact, (b) SP ligament, unilateral anterior SI ligaments, and ipsilateral sacrospinous and sacrotuberous ligaments disrupted (anteroposterior compression type II injury), and these injuries fixed using (c) a 4.5-mm narrow two-hole DC plate placed on the superior SP held by two cancellous bone screws, (d) the DC plate well as a single 7.0-mm cannulated cancellouoffliosacral lag screw across the injured SI joint, (e) the DC plate and a five-hole 3.5-mm reconstruction plate on the anterior SP, (f) a 3.5-mm, four-hole, DC plate on the superior SP using four fully threaded screws, and (g) the box plate symphyseal construct described above. All fixations reduced SP joint gapping compared to the disrupted joint. However, all but the box plate still allowed significantly greater motion than the intact SP joint. No fixation significantly reduced SI joint gapping or sacral flexion compared to the injured state.

Aged↗
PubMed1994

Biomechanical simulation of the anteroposterior compression injury of the pelvis. An understanding of instability and fixation.

Seven fresh cadaveric pelvic specimens were biomechanically analyzed. Testing was first performed on intact pelves and then after progressive disruption of the (1) symphysis pubis, (2) unilateral anterior and interosseous sacroiliac ligaments and capsule, (3) ipsilateral sacrospinous and sacrotuberous ligaments; and fixation with a 4.5-mm narrow dynamic compression plate at the symphysis pubis, or a 4.5-mm narrow dynamic compression plate at the anterior sacroiliac joint with and without the symphysis pubis plate, or a 7.0-mm sacroiliac lag screw anchored into the S1 vertebral body with and without the symphysis pubis plate. Symphyseal gapping occurred after isolated symphysis pubis disruption. With additional disruption of the unilateral sacroiliac joint ligaments, symphysis pubis displacement was unaffected; however, the injured sacroiliac joint gap displacement, and sacroiliac joint flexion angulation on both intact and injured sides increased as compared to the specimen in the intact state. Further disruption of the ipsilateral sacrotuberous and sacrospinous ligament complex produced little additional motion at either symphysis pubis or sacroiliac joints. Plate fixation of the symphysis pubis alone reduced symphysis pubis motion, but not sacroiliac motion. Use of sacroiliac fixation alone without a symphysis pubis plate did not affect symphysis pubis motion. The symphysis pubis plate is the key to stabilizing symphysis pubis motion, and similarly, sacroiliac joint fixation is required to control sacroiliac joint motion. Both single iliosacral screws and plates produced equivalent decreases in sacroiliac joint motion.

Biomechanical Phenomena↗
PubMed1993

Injury of the sciatic nerve associated with acetabular fracture.

In order to document functional outcome, we followed fourteen patients who had an injury of the sciatic nerve associated with a displaced acetabular fracture for a mean of twenty-seven months. In three of the patients, the injury was iatrogenic. Electromyography was useful in the localization and determination of the severity of the injury. According to the functional scale that was used, all but one patient had a satisfactory (fair or better) functional outcome, but eleven patients had residual neurological sequelae that ranged from minor paresthesia to footdrop. Seven patients who had an injury of both the tibial and peroneal divisions of the sciatic nerve had complete or nearly complete motor and sensory recovery of the tibial component. The patients who had isolated, mild involvement of the peroneal nerve had a favorable prognosis, but those who had a severe injury of the peroneal component, whether it was isolated or associated with an injury of the tibial component, did not recover good function.

Acetabulum↗