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Biomedical subjects

I R Munro

Publications and source records attributed to I R Munro.

At least 19 recordsLinked to original sources
PubMed1997

Infections in craniofacial surgery: a combined report of 567 procedures from two centers.

This retrospective review of infectious complications was undertaken at two craniofacial centers (Dallas and Philadelphia). Fourteen infections were identified over a 6.5-year period in 567 intracranial procedures primarily for craniosynostosis. There were no infections in infants under 13 months of age and no cases of meningitis. The overall infection rate was 2.5 percent, and 85 percent of infections occurred in secondary reoperative cases. Tracheostomies were not identified as a risk factor for infection. No difference was found in infection rates between patients with shaved and unshaved scalps. Candida and Pseudomonas were the two most common organisms identified, and 28 percent of our infections involved yeast. The average time to diagnose infection was 11.5 days (excluding three patients who averaged 5 months). Thirteen of the fourteen infections were treated surgically with placement of a subgaleal irrigation/drainage system. Initial bony debridement was kept to a minimum. Based on our findings, recommendations are made to further lower infection rates, particularly those caused by opportunistic organisms.

Antibiotic Prophylaxis↗
PubMed1996

Trigonocephaly-associated hypotelorism: is treatment necessary?

This study was designed to examine whether hypotelorism associated with trigonocephaly might be self-correcting. Only patients who required surgical treatment and had undergone preoperative and postoperative anthropometric measurements were included. In no case was any attempt made to correct the hypotelorism surgically. The study sample consisted of 16 patients, of whom 10 underwent preoperative and postoperative computed tomography in addition to anthropometric examinations. The results were compared with sex- and age-matched pooled normal standards, converted to standard Z scores, and analyzed by means of Student's t tests. Both intercanthal and interorbital widths increased significantly postoperatively, with improvements in delta Z scores of 0.445 (p < or = 0.01) and 0.638 (p < or = 0.05). These increases exceeded average growth increments by 1.6 mm for intercanthal width and 1.3 mm for interorbital width. Improvement in the intercanthal widths was significantly greater in the more severely affected children than in those whose conditions were less severe. A greater improvement in interorbital width also was noted in children treated at less than 6 months of age compared with those treated later. The younger the patient at surgery, the greater was the improvement, suggesting that early surgery may somehow release a constraint on interorbital growth.

Aging↗
PubMed1995

Fibroblast growth factor receptor 3 (FGFR3) transmembrane mutation in Crouzon syndrome with acanthosis nigricans.

Crouzon syndrome, an autosomal dominant condition characterized by craniosynostosis, ocular proptosis and midface hypoplasia, is associated with mutations in fibroblast growth factor receptor 2 (FGFR2) (refs 1-3). For example, we have identified 10 different mutations in the FGFR2 extracellular immunoglobulin III (IgIII) domain in 50% (16/32) of our Crouzon syndrome patients. All mutations described so far for other craniosynostotic syndromes with associated limb anomalies--Jackson-Weiss, Pfeiffer, and Apert--also occur in the extracellular domain of FGFR2, as well as FGFR1 for Pfeiffer syndrome. In contrast, only FGFR3 mutations have been reported in dwarfing conditions--achondroplasia, thanatophoric dysplasia, and hypochondroplasia. For achondroplasia, greater than 99% of mutations occur in the FGFR3 transmembrane domain. We now report the unexpected observation of a FGFR3 transmembrane domain mutation, Ala391Glu, in three unrelated families with Crouzon syndrome and acanthosis nigricans, a specific skin disorder of hyperkeratosis and hyperpigmentation. The association of non-dwarfing and even non-skeletal conditions with FGFR3 mutations reveals the potential for a wide range of FGFR pleiotropic effects as well as locus heterogeneity in Crouzon syndrome. Our study underscores the biologic complexity of the FGFR gene family.

Acanthosis Nigricans↗
PubMed1995

Transfacial approaches to the cranial base.

This article classifies and describes the anterior transfacial approaches to the cranial base as determined by the anatomic location of the lesions. With the use of craniofacial techniques, many of these lesions now may be resected without any significant functional or anesthetic morbidity.

Adolescent↗
PubMed1995

Observations on the use of rigid fixation for craniofacial deformities in infants and young children.

With the introduction of smaller plating systems, many surgeons have adopted their use for craniofacial procedures in infants and small children. We have encountered some previously undescribed problems associated with the use of plates and screws in infants and children. These problems can be classified into three general areas: 1) Plate displacement. This occurs after placement of the metal plates on the outside of the infant calvaria. With subsequent growth, these plates and screws may be found along the inner cortex of the skull with screw points embedded through dura. 2) Plate and screw isolation. In certain locations in young children, plates placed on the outer cortex of bone may later be found to be more prominent, isolated on a peninsula of bone. 3) Plate placement. We have also encountered plates that have been placed along the inner cortex of the skull during a previous operative procedure. This makes subsequent surgery extremely difficult and may increase the risk for secondary surgery. We propose that a previously described model for growth, involving areas of bony resorption and deposition, may be responsible for the observed plate displacement.

Bone Plates↗
PubMed1994

The coronal incision revisited.

The coronal scalp incision often leaves a noticeable scar causing the hair to part away from it, especially when wet. Changing the straight-line to a zigzag incision, called the stealth incision, eliminates this obvious deformity.

Child↗
PubMed1993

Massive teratomas involving the cranial base: treatment and outcome--a two-center report.

Massive teratomas involving the cranial base are extremely rare, and to our knowledge, there are no reports of this condition in surviving children. We describe the management of four cases of massive intracranial teratomas, reflecting a combined experience from two major referral centers. We found that when corrected at an early age, the brain parenchyma demonstrated a remarkable ability to reexpand in those children who had appeared to have sustained parenchymal deficits secondary to the mass effect from the tumor. Follow-up thus far suggests that regional skull growth potential may be compromised in some of these patients. Often, the exact pathologic diagnosis of these entities is somewhat different, since they may fall somewhere within the hamartoma-heterotopia-teratoma continuum. We believe that the best care of these children is offered through a combined simultaneous craniofacial and neurosurgical approach.

Child, Preschool↗
PubMed1993

Cranioscoliosis.

We have identified a particular facial asymmetry with unique characteristics that we call cranioscoliosis. Cranioscoliosis is a condition in which there is an apparent curvature of the midline of the cranial skeleton, cranial base, and facial skeleton when viewed in the axial plane. Cranioscoliosis is a diagnosis of exclusion. It is differentiated from the craniosynostoses by an absence of fused calvarial vault sutures. We recently developed a new technique, called cranial expansion, that involves interdigitating cuts in the calvaria which are subsequently expanded. We retrospectively reviewed the records of 13 patients identified as having this condition, of whom 7 were surgically treated. Our results seem to indicate that cranioscoliosis involves an inherent growth disturbance that does not appear to be corrected through any early surgical release.

Bone Transplantation↗
PubMed1992

Reconstruction of avulsed scalp after go-cart injury.

Scalp avulsion is a rare injury that has significant physical and psychological consequences. It may require emergency replantation or late, challenging surgical reconstruction, or both. The authors describe two patients who had scalp avulsion. Each patient got long hair entangled in the uncovered engine of a go-cart. One underwent unsuccessful replantation without vascular repair; the other had a large segment of scalp successfully replanted with microvascular repair. Both patients required late reconstruction with tissue expansion. The final results were good. When feasible, microvascular replantation is the treatment of choice. If replantation is not possible, temporary cover by skin grafts followed by later reconstruction with tissue expansion can be effective.

Child↗
PubMed1989

Rigid fixation and facial asymmetry.

The use of rigid fixation for the correction of facial asymmetry is in principle no different from its use in other forms of craniomaxillofacial deformity. The use of screws and plates demands more precise techniques than the use of wires. Attention to detail in passively fitting the plate to the defect and accurate insertion of the drill holes and screws enables the production of good occlusion and a symmetrical face. The precise osteotomies and bone grafts needed in the correction of all forms of skeletal asymmetry are as described for hemifacial microsomia or temporomandibular ankylosis. In a young child whose secondary dentition has not yet erupted it is not possible to insert screws, neither is the bone in a costochondral graft solid enough to permit screw fixation without the use of intermaxillary fixation. Therefore, rigid fixation can be used for osteotomies and bone grafts in patients whose main permanent dentition has erupted and in whom the cortex of the bone graft is strong enough to retain the screws against the pull of facial muscles.

Bone Transplantation↗
PubMed1989

The Luhr fixation system for the craniofacial skeleton.

The use of miniplates and screws in elective osteotomies or acute trauma of the craniofacial skeleton has revolutionized this field. In jaw surgery, rigid fixation has eliminated the need for intermaxillary fixation in most cases. Bone grafts and bone segments are more easily kept in place by screws or plates, rather than the balancing act that had to be done with wire fixation. This has decreased morbidity and the risks of postoperative airway obstruction. Thus, more complex procedures can be done and younger children treated. Most craniofacial surgeons now using plates and screws are finding less postoperative swelling after elective surgery. The reason for this is not immediately obvious, although supposition is possible. The disadvantages of the use of plates and screws are, first, that the surgery must be more precise than when wire fixation is used especially jaw surgery. Second, all the systems are more expensive than wires. However, in a well-organized insurance system, the cost is offset by decreased use of intensive care units, decreased hospital stay, greater safety and less morbidity for the patient, and probably fewer complications from slippage of bone segments or infection.

Bone Plates↗
PubMed1989

Growth after construction of the temporomandibular joint in children with hemifacial microsomia.

Free costochondral grafts have been used to construct the absent ascending ramus and condylar head of 22 children with hemifacial microsomia (HFM) who were less than 14 years of age. Evidence of continued growth was demonstrated in all patients. Growth was determined by measurement of cephalograms or by inference; if the patient grew extensively in height but his/her face remained symmetric, the graft was inferred to have grown. In two patients, considerable overgrowth occurred, displacing the chin to the opposite side and causing a class III malocclusion. Variations in age or type of adjunctive operations did not affect growth. There appears to be no single explanation for all findings. Because all of the grafts grew, early joint construction and correction of hemifacial microsomia are advocated.

Adolescent↗
PubMed1989

Rigid fixation of facial osteotomies.

Rigid fixation of facial osteotomies has had a significant effect on reducing morbidity in these patients. Any osteotomy in a patient with erupted permanent dentition previously fixed with wires and intermaxillary fixation can now be managed by metal plates and screws, eliminating or decreasing the need for the jaws to be held together. The problems of palpable plates and screws and malposition of jaws have been eliminated by precise techniques. The cost of plates and screws and the increased time needed for their application have been offset by decreased hospitalization time and fewer complications. A new microsystem with screws 0.8 mm in diameter and plates 0.5 mm in thickness has further expanded the fields for application, particularly in children and infants.

Bone Plates↗
PubMed1988

Changes in aesthetic appearance and intelligibility of speech after partial glossectomy in patients with Down syndrome.

Eight patients with Down syndrome, aged 9 years and 10 months to 25 years and 4 months, underwent partial glossectomy. Preoperative and postoperative videotaped samples of spoken words and connected speech were randomized and rated by two groups of listeners, only one of which knew of the surgery. Aesthetic appearance of speech or visual acceptability of the patient while speaking was judged from visual information only. Judgments of speech intelligibility were made from the auditory portion of the videotapes. Acceptability and intelligibility also were judged together during audiovisual presentation. Statistical analysis revealed that speech was significantly more acceptable aesthetically after surgery. No significant difference was found in speech intelligibility preoperatively and postoperatively. Ratings did not differ significantly depending on whether the rater knew of the surgery. Analysis of results obtained in various presentation modes revealed that the aesthetics of speech did not significantly affect judgment of intelligibility. Conversely, speech acceptability was greater in the presence of higher levels of intelligibility.

Adolescent↗
PubMed1988

Patterns of dysmorphology in Crouzon syndrome: an anthropometric study.

Twenty-four craniofacial proportion indices were calculated from 26 surface measurements taken directly from the head and face in 61 patients with Crouzon syndrome, aged 11 days to 32 years. All patients were North American caucasians who had not undergone facial repair. The measurements and proportions were compared with those in healthy controls of the same age and sex. In most patients, the only disproportions present were a wide forehead in relation to the cranial breadth and wide orbital region compared with the face width. The proportions were in the normal range in most cases (71.7%), although many tended toward its extremities. Disproportions were associated most frequently with a combination of abnormal and normal measurements (48.9%); however, a large number (42.4%) involved two normal measurements. Among the normal proportions, most involved two normal measurements, although almost one fourth (22.8%) were associated with one or two abnormal measurements.

Adolescent↗
PubMed1988

Craniofacial surgery: airway problems and management.

Airway problems are the greatest cause of morbidity and mortality during operations to repair craniofacial anomalies. These problems can be managed by awareness of the risks and prophylactic intervention rather than by desperate steps when acute problems occur in treatment. Airway obstruction is the major problem in managing patients with such deformities in the preoperative period, at the time of intubation, during the operation, and in the early postoperative period. Congenital craniofacial problems that may lead to airway difficulties are extremely rare, and for physicians to gain sufficient experience to prevent morbidity, these patients should be referred to regional centers, where at least two or three such operations are performed per week.

Anesthesia↗