Jeffrey L. Marsh

Three dimensional computer graphics for craniofacial surgical planning and evaluation

The understanding of complex craniofacial deformities has been aided by high resolution computed tomography. Nonetheless, the planar format limits spatial comprehension. Reconstruction of fully three-dimensional bony and soft tissue surfaces from high resolution CT scans has been accomplished by a level slicing edge detector coupled to a hidden surface processor without perspective depth transformation. This method has clarified aberrant anatomy, facilitated surgical planning and improved quantitative postoperative evaluation in more than 200 clinical cases. Advanced computer aided design techniques, originally developed for the manufacture of military aircraft, have been applied to the planning and evaluation of craniofacial procedures as well. This allows the application of interactive digital graphic technology to surgical patient management.

The “third” Dimension in Craniofacial Surgery

A new method for reconstruction of a three-dimensional surface from a sequence of high-resolution axial CT scans has been developed. This algorithm is realized as a set of computer programs that can operate on commercially available CT scanners or evaluation consoles. The program is both efficient and easy to implement. No operator intervention is required. The images produced simulate photographs of the skull. Frontal, lateral, oblique, birds eye, worms eye, and rear views are generated. As with photographs and conventional radiographs, each of these projections uniquely displays specific anatomic details. This method of osseous surface reconstruction is now routinely applied to all patients evaluated for major craniofacial reconstruction at our institution. The images are useful in defining aberrant anatomy, planning surgical procedures, and evaluating the results of such operations. This method replaces an inexact concept in the surgeons imagination with a three-dimensional image of the craniofacial skeleton.

Comparative three-dimensional analysis of CT-scans of the calvaria and cranial base in Apert and Crouzon syndromes

The purpose of this study is to describe and analyze Apert and Crouzon skulls from three-dimensional (3-D) reconstructions of CT-scans. 12 Apert patients and 19 with Crouzon syndrome were included in the study. The age range was 0 to 23 years. All CT-scannings were carried out according to the same protocol with a slice thickness of 2 or 4 mm and 3-D reconstructions of the craniofacial region included midsagittal and horizontal cuts. A number of qualitative characteristics of the calvaria and cranial base were recorded and the cranial base angle was measured on the 3-D models. Our results showed that Apert and Crouzon syndromes are very different in cranial development and their dysmorphology is highly age dependent. We suggest that cartilage abnormalities, especially in the anterior cranial base, play a primary role in cranial development in the Apert syndrome from very early intrauterine life. Several cranial anomalies observed postnatally, however, are caused by the resultant dysmorphic and compensatory growth and are probably compounded by early cranial deformation. The primary abnormality in Crouzon syndrome appears to be premature fusion of sutures and synchondroses. Based on the findings at birth and early infancy it would seem that such fusions occur relatively late in fetal life. The adult cranial form in Crouzons patients is explainable by resultant dysmorphic and compensatory growth changes. Very early release of the coronal suture areas with advancement of the frontal bone is advocated in both syndromes but for somewhat different reasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Sagittal craniosynostosis outcome assessment for two methods and timings of intervention.

A retrospective quantitative analysis of 40 infants who underwent surgery for sagittal craniosynostosis was conducted to determine whether any difference in outcome, with respect to cranial index (cranial width/cranial length x 100), could be associated with either the age at surgery or the extent of the operation. Children < or = 13 months old at surgery and for whom there were archived computed tomography digital data preoperatively, perioperatively, and 1 year postoperatively were studied. For statistical analysis, the operation was classified as either extended strip craniectomy or subtotal calvarectomy, and the age at operation was either < or = 4 months or > 4 months. Twenty-eight patients underwent extended strip craniectomy at a mean age of 5.1 months. Their mean cranial index preoperatively was 67 versus 71 at 1 year postoperatively (p < 0.0001). Of extended strip craniectomy patients, 15 were operated on at age < or = 4 months (mean = 2.9 months) and 13 at age > 4 months (mean = 7.6 months). Mean cranial indices for age at operation groups did not achieve age-appropriate normal range values 1 year postoperatively for either group, and there was no significant difference between the mean percentages of improvement achieved (p = 0.143). Twelve patients underwent subtotal calvarectomy at a mean age of 5.2 months. Their mean cranial index preoperatively was 66 versus 74 at 1 year postoperatively (p < 0.0001). The mean cranial index in this group reached age-appropriate normal range values 1 year postoperatively. The percentage improvement in cranial index 1 year after subtotal calvarectomy was greater than after extended strip craniectomy (p = 0.003). Extended strip craniectomy for sagittal craniosynostosis does not achieve normal cranial width:length proportions, even when performed before 4 months of age. Subtotal calvarectomy for sagittal craniosynostosis does achieve normal cranial width:length proportions in the majority of the children, at least when performed within the first 13 months of life.

Long-term studies of metopic synostosis : frequency of cognitive impairment and behavioral disturbances

&NA; Although the occurrence of cognitive impairment and behavioral disturbances in patients with metopic synostosis has been described, the incidence of this dysfunction has not been established. The records of 36 consecutive children with metopic synostosis followed at one craniofacial center from 1978 to 1993 were reviewed and parental questionnaires were completed to establish the frequency of mental retardation, learning disabilities, and behavioral problems associated with this synostosis. Documentation of syndromes, abnormal karyotype, and central nervous system anomalies also was done. The study group consisted of 27 males and 9 females. The average age at most recent follow‐up was 7 years and 1 month (range 6 months to 22 years). Two patients had chromosomal abnormalities (9p syndrome and trisomy 21). On the basis of CT and MRI scans, intracranial anomalies were identified for only one patient having an absent corpus callosum. Thirty‐two of the study patients had adequate information for longitudinal assessment. Twenty patients have normal development without apparent disability. Of these, those of school age are at appropriate grade level. Eight patients have mild to moderate learning disabilities or behavioral problems, including attention deficit hyperactivity disorder and impaired language development. Four patients have significant mental impairment. Impaired cognitive development was not limited to children with abnormal karyotype or central nervous system anomaly. Cognitive and behavioral abnormalities occur in at least a third of patients with metopic synostosis. The, at times, subtle nature of these abnormalities mandates longitudinal developmental and neurologic evaluation for infants with metopic synostosis. (Plast. Reconstr. Surg. 97: 276, 1996.)

Neonatal distraction surgery for micrognathia reduces obstructive apnea and the need for tracheotomy.

The objective of the study was to assess the effectiveness of neonatal mandibular distraction in treatment of obstructive sleep apnea in the perinatal period in preventing a tracheotomy. This was a prospective study of 17 infants at two centers with severe micrognathia who demonstrated obstructive sleep apnea refractory to conservative therapy. Age at surgery varied from 5 to 120 days. Distraction was performed at a rate of 2 mm/d. After distraction, callus consolidation was allowed for 4 to 6 weeks, and the device was then removed. Each child underwent a three-dimensional computed tomography scan before surgery and approximately 3 months after surgery. Of the 17 patients, 14 successfully underwent extubation and demonstrated significant improvement in the obstructive sleep apnea. Postoperative horizontal ramus length increased from 23.3 to 34.8 mm after surgery. Mean maxillary mandibular discrepancy was 8.28 mm before surgery and 2.2 mm after surgery. Ten infants who underwent pre- and postoperative polygraphic studies showed improvement in obstructive apnea. Three patients had postoperative polysomnographic studies only; the results were also within the normal range. The mean follow-up interval was 16.5 months (range: 8–48 months). Neonatal distraction is an effective method for treatment of micrognathia with obstructive sleep apnea in the perinatal period in preventing a tracheotomy.

the Effect of Surgeon Experience on Velopharyngeal Functional Outcome following Palatoplasty: Is There a Learning Curve?

&NA; There is little information in the cleft palate literature concerning the relationship between surgeon volume and clinical outcomes. It is unknown whether such a relationship applies specifically to velopharyngeal dysfunction and the need for secondary physical management of the velopharynx. The purpose of this paper was to explore the concept of an operative learning curve for different surgeons with respect to palatoplasty. Impact of case volume and procedure type on the occurrence of secondary palatal management (the main outcome measure) was assessed. The charts of 472 consecutive palatoplasty patients were reviewed by one speech and language pathologist to determine when the palatoplasty was performed, which surgeon (n = 9) performed the palatoplasty, whether velopharyngeal status was documented at a minimum of 6 years of age, and whether secondary palatal management was prescribed. The results were analyzed by year of palatoplasty, by surgeon, and by number of operations per surgeon to determine total and individual surgeon rates of secondary palatal management. There were 401 palatoplasties (85 percent recovery) with adequate documentation of velopharyngeal status by at least 6 years of age. Palatoplasty rates ranged between 1 and 258 palatoplasties per surgeon. Over the 12 years reviewed, secondary palatal management was performed for 92 patients (23 percent) of the study population. Examination of the proportion of palatoplasty patients receiving secondary palatal management by surgeon and by year showed only one surgeon with a pattern suggesting a learning curve. The proportion of patients receiving secondary palatal management was plotted against the total number of surgeries the surgeon performed. There was a strong relationship between experience and success. The number of procedures this surgeon performed per year increased at approximately the same time as the success rate improved. The categories of “total procedures” and “procedure per year” were highly correlated with each other. Success rates were analyzed by number of procedures performed per year, and there was a clear association between the two variables. To separate the effect of the two variables, a multiple regression model was constructed. The category of “total procedures” was statistically significant in the model, whereas procedures per year was not, suggesting that the key to the dominant surgeons improvement was cumulative experience rather than frequency of performance of the operation. Palatoplasties performed by high‐volume surgeons are more likely to result in better postoperative outcomes (i.e., lower rates of secondary palatal management) as compared with palatoplasties performed by low‐volume surgeons. The influence of the surgeons cumulative experience on improvement seems to be more important than the frequency of performance of primary palatoplasty. (Plast. Reconstr. Surg. 102: 1375, 1998.)

Hydrocephalus and mental retardation in craniosynostosis.

We prospectively studied craniosynostosis, regardless of neurologic status, by cranial computed tomography or psychometric testing in 56 children. None of the 27 children with simple craniosynostosis (single or multiple suture involvement) had evidence of hydrocephalus on CT scan. Of the 24 patients with simple craniosynostosis who underwent psychometric testing, 17 were of average intelligence; six were in the low average range. The single mentally retarded child had a history of severe perinatal asphyxia. Hydrocephalus occurred more frequently (five of 23 cases) in children with complex craniosynostosis syndromes, including Pfeiffer syndrome, Crouzon syndrome, and kleeblattschädel deformity. More striking than hydrocephalus, however, was the finding of dysmorphic ventricular dilation in eight patients, including the three children with Apert syndrome and four with Crouzon syndrome. Nineteen of the 25 children with complex craniosynostosis syndromes receiving psychometric testing were of normal intelligence. Four children with borderline normal intelligence had either hydrocephalus or ventricular dilation. The two children with mental retardation were sisters with Crouzon syndrome whose family included other retarded individuals. This study indicates that the incidence of hydrocephalus and mental retardation in craniosynostosis is lower than reported previously.

Long-term outcome of autogenous rib graft nasal reconstruction.

&NA; Whereas reconstruction of the hypoplastic nose with rib grafting is common, the long‐term outcomes of nasal growth and aesthetics are unknown. This study assessed nasal morphometrics, patient satisfaction, and the perception of nasal appearance by others up to 15 years after nasal reconstruction using cantilevered autogenous chondro‐osseous rib grafting with rigid internal fixation in children. Records of all patients who received nasal rib grafts between 1983 and 1998 by one senior surgeon were reviewed. Patients in this study were operated on before their late teens and had greater than 1‐year follow‐up including serial photographic documentation. Nasal growth was determined by comparing anthropometric measurements preoperatively, perioperatively, and postoperatively. Patient satisfaction was determined through a questionnaire that addressed memory, donor‐site morbidity, and nasal perception. Independent, blinded skilled observers who reviewed frontal and lateral photographs of the preoperative, perioperative, and postoperative intervals assessed nasal aesthetics. Thirty‐two patients who underwent 38 rib graft reconstructions of the nasal dorsum and tip at an average age of 8.8 years constitute the study population. Six patients underwent secondary augmentation. The average interval between initial nasal reconstruction and evaluation for this study was 7.9 years. Comparative anthropometric measurements before and after surgery documented increases in both tip projection (2.3 percent) and nasal length (3.0 percent) and a decrease in nasolabial angle (1.9 percent). Patient satisfaction interview response rate was 100 percent of those whom we were able to contact (28 of 32). The average age at interview was 17.2 years. Most patients recalled the operation and denied recollection of pain. Donor‐site long‐term morbidity was not an issue for 86 percent of patients. Sixty‐four percent of patients remembered their preoperative nasal appearance and 89 percent of these preferred the postoperative change and were not concerned with nasal scars or texture. Almost two‐thirds of the patients had fixation screws removed from the nasal dorsum because of skin erosion, easy palpability, or visibility. Although several patients expressed a desire to make minor additional changes to their nose, only one of these elected offered presurgical consultation and none have had such surgery. The postoperative nasal appearance compared with that preoperatively was rated as improved for 66.3 percent of responses, 26.5 percent as unchanged, and 7.2 percent as deteriorated. Cantilevered autogenous chondro‐osseous rib graft reconstruction of the nasal dorsum is an effective means of reconstruction for the hypoplastic nose in childhood with respect to morphometric measurements, patient self‐perception, and the assessment of nasal appearance by others. (Plast. Reconstr. Surg. 108: 1895, 2001.)

Relationship between bone and muscles of mastication in hemifacial microsomia

&NA; The relationship between the bone and muscles of mastication in hemifacial microsomia was studied using three‐dimensional volumetric computed tomography scans and image processing techniques. High resolution head computed tomography scans were obtained from 31 patients with unilateral hemifacial microsomia and eight normal patients. Using three‐dimensional volume renderings of bone, mandibular deformities in patients with hemifacial microsomia were classified using the Pruzansky system. For each patient, specific craniofacial bones (temporal bone, maxilla mandible) and the muscles of mastication (masseter, temporalis and lateral and medial pterygoid) were segmented bilaterally from the image volume for independent display and volume measurement. Volumes were expressed as the ratio of the affected: unaffected sides. For the masseter and temporalis, the relationship between muscular hypoplasia and osseous hypoplasia in its origin and insertion was studied by plotting affected:unaffected bone volume as a function of affected:unaffected muscle volume for each muscle, bone of origin, bone of insertion triplet. The volumes of the pterygoid muscles were compared with hemimandibular volumes. The precision of object segmentations was examined by repetitive definition tasks, whereas the accuracy of volume measurement was tested by scanning custom‐made phantom objects and comparing digital to physical object volume measurements. Volume measurements performed using these techniques were both accurate and precise. In hemifacial microsomia, the extent of hypoplasia of specific muscles of mastication predicted the extent of dysplasia in their osseous origin and insertion. However, the reverse was not true. The extent of hypoplasia of the facial bones did not necessarily predict the extent of hypoplasia in the attached muscles of mastication. Pruzansky grade of the mandible described the degree of mandibular hypoplasia on the affected side, but was inconsistent in its prediction of volume decrease of the other facial bones.