A Prospective Study to Examine Responsiveness and Minimally Important Differences (MIDs) for the CLEFT-Q Scales Following Three Cleft-Specific Operations.

The aim of this study was to examine internal responsiveness and estimate minimally important differences (MIDs) for CLEFT-Q scales.In this prospective cohort study, participants completed the CLEFT-Q appearance and health-related quality of life (HRQL) scales before and six months after cleft-related surgery.Seven cleft centres in Canada, USA and UK participated.Patients were ages 8-29 years with CL/P.Patients underwent rhinoplasty, orthognathic or cleft lip scar revision surgery.Internal responsiveness was examined using Cohen's d effect sizes (ESs) based on the following interpretation: 0.20-0.49 small, 0.50-0.79 moderate and ≥ 0.80 large. MIDs were estimated using two distribution-based approaches.Participants had a rhinoplasty (n = 31), orthognathic (n = 21) or cleft lip scar revision (n = 18) surgery. Most participants were males (56%) and aged 8-11 years (41%). Following rhinoplasty, ESs were larger for the nose (0.92, p = 0.001) and nostrils (0.94, p < 0.001) scales than for the face scale (0.51, p = 0.003). MIDs ranged between 6.2-10.4. For orthognathic surgery, larger ES was observed for the jaws scale (1.80, p < 0.001) compared with the teeth (1.16, p < 0.001), face (1.15, p = 0.001) and lips (0.94, p < 0.001) scales. MIDs ranged between 5.9-14.4. In the cleft lip scar revision sample, the largest ES was observed for the nose scale (0.76, p = 0.03), followed by lips (0.58, p = 0.009) and cleft lip scar (0.50, p = 0.043) scales. MIDs ranged between 6.4-12.3.CLEFT-Q detected change in key outcomes for three cleft-specific surgeries, providing evidence of its responsiveness. Estimated MIDs will aid in interpreting this PROM.

Hearing impairment and ear anomalies in craniofacial microsomia: a systematic review.

The aim of this systematic review was to review the literature on hearing impairment and ear anomalies in patients with craniofacial microsomia and to determine their prevalence. Sixty-two records including 5122 patients were included. Ear anomalies were present in 52-100% of patients. The most reported external ear malformations were microtia, pre-auricular tags, and atresia of the external auditory canal. Ossicular anomalies were the most reported middle ear malformations, whereas the most reported inner ear malformations included oval window anomalies, cochlear anomalies, and anomalies of the semicircular canals. Hearing loss in general was reported in 29-100% of patients, which comprised conductive hearing loss, mixed hearing loss, and sensorineural hearing loss. Between 21% and 51% of patients used hearing aids, and 58% underwent a surgical intervention to improve hearing. The relationship between different phenotypes of craniofacial microsomia and the type and severity of hearing loss is mostly unclear. In conclusion, the high prevalence of ear and hearing anomalies in patients with craniofacial microsomia underlines the importance of audiological screening in order to facilitate individual treatment.

Continuous bupivacaine infusion post-iliac crest bone graft harvesting in pediatric cleft surgery: role and comparison with ketorolac.

OBJECTIVE: To investigate the use of intravenous ketorolac and iliac crest bupivacaine infusion in the management of iliac crest donor-site pain in the pediatric cleft population. The null hypothesis was there is no difference with respect to pain scores between ketorolac and iliac crest bupivacaine infusion as analgesic adjuncts to intravenous opioids. METHODS: A total of 54 children and adolescents (27 boys, 27 girls) undergoing alveolar cleft repair or Le Fort I osteotomy were assigned randomly in a prospective, single-blinded fashion to one of three groups: intravenous ketorolac plus iliac crest normal saline infusion, intravenous ketorolac plus iliac crest bupivacaine infusion, or iliac crest bupivacaine infusion alone. Iliac crest infusions and ketorolac were administered for 48 hours or until discharge, whichever occurred first. All patients received morphine via a patient-controlled analgesia device. MAIN OUTCOME MEASURE(S): Primary outcome was pain score, and secondary outcomes were morphine consumption and satisfaction scores. RESULTS: Pain scores, morphine consumption, and satisfaction scores were not significantly different among groups. Estimated costs were significantly higher for bupivacaine infusion than intravenous ketorolac. CONCLUSIONS: Iliac crest donor-site pain is well managed in this patient population. Intravenous ketorolac and iliac crest bupivacaine infusion provide comparable analgesia for iliac crest bone graft donor-site pain in children and adolescents.

Ocular and adnexal anomalies in craniofacial microsomia: Type and prevalence in a multicentre cohort study.

The aim of this multicentre retrospective cohort study was to describe and categorize the types of ocular and adnexal anomalies seen in patients with craniofacial microsomia (CFM) and to determine their prevalence. In addition, the relationship between the OMENS-Plus and Pruzansky-Kaban classification for each patient and the presence of ocular anomalies was investigated. A total of 881 patients with CFM from four different craniofacial centres were included. Data on ocular anomalies were gathered from the patient charts. Ocular anomalies were present in 33.9% of patients. Four subgroups of ocular and adnexal anomalies were identified. Type I ocular anomalies were present in 22.2%, type II in 19.0%, type III in 18.4%, and type IV in 14.5%. Several potentially preventable and treatable ocular anomalies were identified. Higher OMENS-Plus classification orbit and soft tissue scores and Pruzansky-Kaban classification mandible scores were associated with an increased risk of ocular anomalies. Based on these results and the clinical implications ocular anomalies may have, we underline the importance of targeted ophthalmological screening in CFM. Healthcare professionals should be aware of the possibility of ocular anomalies in these patients, especially during the critical period for visual development.

Ocular and adnexal anomalies in craniofacial microsomia: a systematic review.

Ocular anomalies may occur in craniofacial microsomia (CFM). The aim of this systematic review was to review the literature on ocular anomalies and their incidence, in order to estimate the need for ophthalmological screening in CFM patients. Online databases were searched, and data on the number of patients, type and incidence of ocular anomalies, and visual acuity were extracted. Four subgroups of ocular and adnexal anomalies were identified, to provide an overview of the different anomalies. Twenty-five papers analysing 1419 patients in total were included. Ocular anomalies were documented in 6.7-100% of patients. The most reported type I ocular anomalies were eyelid coloboma, lipodermoids, and orbital dystopia. The most reported type II ocular anomalies were epibulbar dermoid, microphthalmia, and anophthalmia. Ptosis and strabismus were the most reported type III anomalies, and irregular astigmatism was the most reported type IV ocular anomaly. Visual impairment in general was reported in 8-71.4% of patients, with severe visual impairment in 11.1-71.4% and amblyopia in 16.3%. This study provides a detailed overview of ocular anomalies in CFM and their prevalence. Furthermore, we propose a new classification to organize ocular anomalies into four clinically relevant subtypes. Finally, the high prevalence of ocular anomalies and visual impairment in this study suggests that CFM patients should undergo ophthalmological screening at least once during the sensitive period.

Extracraniofacial anomalies in craniofacial microsomia: retrospective analysis of 991 patients.

Craniofacial microsomia (CFM) is characterized by unilateral or bilateral underdevelopment of the facial structures arising from the first and second pharyngeal arches, but extracraniofacial anomalies may also be present. This retrospective study provides an overview of the prevalence, types, and characteristics of extracraniofacial anomalies in patients with CFM. All patients diagnosed with CFM seen at four craniofacial centres were included. The patient charts were reviewed and data on patient characteristics and extracraniofacial anomalies were extracted. Of the 991 patients included, 462 (47%) had extracraniofacial anomalies. The prevalence of extracraniofacial anomalies in the various tracts was as follows: vertebral 28%, central nervous system 11%, circulatory system 21%, respiratory tract 3%, gastrointestinal tract 9%, and urogenital tract 11%. Compared to patients without extracraniofacial anomalies, those with an extracraniofacial anomaly were at higher risk of having additional extracraniofacial anomalies in other tracts. The prevalence of extracraniofacial anomalies was greater in patients with bilateral CFM, a more severe mandibular deformity, or facial nerve or soft tissue deformity. Patients with CFM should be screened for extracraniofacial anomalies by physical examination with specific attention to the circulatory, renal, and neurological tracts. Diagnostically, electrocardiography, echocardiography, spine radiography, and renal ultrasound should be performed for patients at risk of extracraniofacial anomalies.

Vertebral anomalies in craniofacial microsomia: a retrospective analysis of 991 patients.

Craniofacial microsomia (CFM) is characterized by an underdevelopment of the facial structures arising from the first and second branchial arches, but extracraniofacial anomalies such as vertebral anomalies may be present. This retrospective study was performed to determine the prevalence and types of vertebral anomalies and the association with other extracraniofacial anomalies in patients with CFM. The charts of all patients diagnosed with CFM seen in four craniofacial centres were reviewed for the presence of vertebral anomalies, symptoms, extracraniofacial anomalies, and the OMENS classification including the Pruzansky-Kaban type of mandibular deformity. A total of 991 patients were included and 28% of the patients had vertebral anomalies. The most common vertebral anomalies included scoliosis, block vertebrae, and hemivertebrae. Only 44% of the patients with vertebral anomalies had clinical symptoms; torticollis, back or neck pain, and limited neck movement were the most frequently seen. The prevalence of vertebral anomalies was greater in patients with bilateral CFM and in patients with a more severe mandibular deformity, and/or orbit, facial nerve, and/or soft tissue involvement. Patients with vertebral anomalies had significantly more extracraniofacial anomalies than patients without vertebral anomalies. Therefore, patients with vertebral anomalies should undergo cardiac, renal, and neurological evaluation.

Central nervous system anomalies in craniofacial microsomia: a systematic review.

Extracraniofacial anomalies, including central nervous system (CNS) anomalies, may occur in craniofacial microsomia (CFM). This systematic review was performed to provide an overview of the literature on the prevalence and types of CNS anomalies and developmental disorders in CFM, in order to improve the recognition and possible treatment of these anomalies. A systematic search was conducted and data on the number of patients, patient characteristics, type and prevalence of CNS anomalies or developmental delay, and correlations between CFM and CNS anomalies were extracted. Sixteen papers were included; 11 of these described developmental disorders. The most common reported anomalies were neural tube defects, corpus callosum agenesis or hypoplasia, intracranial lipoma, Arnold-Chiari malformations, hydrocephaly, ventriculomegaly, and cerebral hypoplasia. The prevalence of CNS anomalies in CFM varied from 2% to 69%. The prevalence of developmental disorders, such as intellectual disability, language or speech developmental delay, and neuropsychomotor delay, varied from 8% to 73%. This study suggests that CNS anomalies and developmental disorders are seen in a substantial proportion of patients with CFM. Further research should focus on determining which features of CFM are correlated with CNS anomalies to allow adequate screening and timely care.

Vertebral anomalies in craniofacial microsomia: a systematic review.

Craniofacial microsomia (CFM) is characterized by a heterogeneous underdevelopment of the facial structures arising from the first and second branchial arches, but extracraniofacial malformations such as vertebral anomalies also occur. This systematic review provides an overview of the literature on the types and prevalence of vertebral anomalies found in patients with CFM. A systematic search was conducted. Data on the number of patients, patient characteristics, types and prevalence of vertebral anomalies, and other associations between CFM and vertebral anomalies were extracted from the articles identified. Thirty-one articles were included. Seventeen articles described both the prevalence and types of vertebral anomalies in CFM, five articles described solely the types of vertebral anomalies in CFM, and nine articles reported solely the prevalence of vertebral anomalies in CFM. The vertebral anomalies most often reported in CFM are hemivertebrae, block vertebrae, scoliosis/kyphoscoliosis, and spina bifida. These anomalies are mostly present in the cervical and thoracic spine and ribs. The reported prevalence of vertebral anomalies in CFM varies from 8% to 79%. To diagnose vertebral anomalies early in patients with CFM, further research should focus on determining which patients with CFM are at risk of vertebral anomalies.

Long-term orthognathic surgical outcomes in Treacher Collins patients.

INTRODUCTION: Treacher Collins syndrome is a rare disorder characterized by several orofacial findings including malar deficiency and hypoplastic mandibles. These patients often require a combined orthodontic-orthognathic approach to correct their malocclusion. This is most often characterized by a short posterior vertical height and an anterior open bite. Orthognathic correction often requires Le Fort I and bilateral sagittal split osteotomies. No long-term stability results have been reported after bimaxillary surgery in Treacher Collins patients. METHODS: A retrospective review of all Treacher Collins patients evaluated for orthognathic surgery by a single surgeon from 1993 to 2007 was performed. Patients were divided into groups who required surgery and those who did not. Part I analyzed the cephalometric differences between the surgical (S) and nonsurgical (NS) groups. Part II of the study assessed the preorthodontic treatment (T1), preoperative (T2), immediate postoperative (T3), and 1-year postoperative (T4) cephalometric measurement variables to determine the net surgical movement (T3 - T2) and relapse (T4 - T3). RESULTS: Twenty-two patients met the inclusion criteria, of which 11 had occlusal relationships requiring orthognathic surgery. Nine out of 11 chose to have surgery. At baseline, surgical patients exhibited a statistically significant retruded maxilla as measured by SNA and midface length compared to the NS group. In addition, the S group also had an increased gonial angle. There were significant movements in all maxillary and mandibular measurements. There was a significant relapse in the palatal plane angle when the maxilla was anteriorly impacted, with a 2.8-mm average relapse of the advancement. Relapse of the counterrotation movement of the mandible was identified, but this was not significant. Relapse did not affect the final occlusal result, which may have been compensated with postsurgical orthodontic treatment. CONCLUSION: Bimaxillary orthognathic surgery in the Treacher Collins patients may be performed safely with long-term dental and skeletal stability.

Acute ischaemic preconditioning protects against skeletal muscle infarction in the pig.

OBJECTIVE: The aims were to investigate the efficacy of acute ischaemic preconditioning for protection of skeletal muscles against infarction and its effect on muscle blood flow and ischaemic muscle metabolism. METHODS: The efficacy of preconditioning was tested by subjecting pig latissimus dorsi and gracilis muscles to different numbers and durations of ischaemia/reperfusion cycles before 4 h of global ischaemia. Infarction was assessed at 48 h of reperfusion, using nitroblue tetrazolium dye. Blood flow in the latissimus dorsi was measured at the end of preconditioning and 1.5 and 3.0 h of reperfusion, using the radioactive microsphere (15 microns) technique. Muscle biopsies were taken from the latissimus dorsi before ischaemia, at the end of 2 and 4 h of ischaemia, and 1.5 h of reperfusion. RESULTS: At least three cycles of 10 min ischaemia and 10 min reperfusion were required for preconditioning of latissimus dorsi and gracilis muscles for protection against infarction. Preconditioning reduced the total infarct size by 44% and 62% in latissimus dorsi and gracilis muscles, respectively. Preconditioning did not affect preischaemia muscle blood flow but it reduced the muscle content (preischaemia reserve) of phosphocreatine and ATP and the muscle energy charge potential (ECP) by 13.5%*, 27.5%*, and 8%* (*P < 0.05), respectively. In spite of a lower preischaemia reserve of phosphocreatine and ATP, the muscle contents of phosphocreatine and ATP and muscle ECP were maintained higher and the lactate lower (*P < or = 0.05) in the preconditioned than in the non-preconditioned (control) muscles at the end of 4 h of ischaemia [phosphocreatine 8.0(SEM 0.4) v 3.2(0.3)*; ATP 9.8(0.7) v 7.8(0.3); ECP 0.72(0.02) v 0.66(0.01)*; lactate 115.4(8.6) v 160.5(11.8)* mumol.g-1 dry muscle]. The level of ATP and ECP also remained significantly higher and the level of lactate significantly lower in the preconditioned than in the non-preconditioned latissimus dorsi muscles at 1.5 h of reperfusion. Hyperaemia was seen in the preconditioned latissimus dorsi muscles at 1.5 h of reperfusion and it subsided by the end of 3h of reperfusion. CONCLUSIONS: The protective effect of preconditioning can be induced in pig skeletal muscle but at a higher threshold than reported previously in pig cardiac muscle (one cycle). Preconditioning of pig skeletal muscle is associated with a lower energy metabolism during sustained ischaemia. At the present time, it is not known if this energy sparing effect is a major mechanism of ischaemic preconditioning against infarction in skeletal muscles.

Acute pharmacologic preconditioning as a new concept and alternative approach for prevention of skeletal muscle ischemic necrosis.

The phenomenon of ischemic preconditioning for augmentation of ischemic tolerance has been well documented in the myocardium of common laboratory animals and human cardiomyocytes. The cellular mechanism of ischemic preconditioning is unclear, but adenosine is most likely the mediator in the rabbit, dog, pig and human. We have demonstrated recently that the protective effect of ischemic preconditioning and adenosine against ischemic injury can also be induced in pig skeletal muscles [116]. We speculate that adenosine is a potential treatment modality for prevention of skeletal muscle ischemic injury in vascular and musculoskeletal reconstructive surgery and in muscle and limb procurement for transplantation in the future. It is hoped that this review will stimulate workers at other laboratories to join the adventure in exploring the cellular mechanism and clinical application of adenosine for augmentation of skeletal muscle ischemic tolerance.

Trigonomicrocephaly, severe micrognathia, large ears, atrioventricular septal defect, symmetrical cutaneous syndactyly of hands and feet, and multiple café-au-lait spots: new acrocraniofacial dysostosis syndrome?

We report on a patient with a unique constellation of anomalies comprising trigonomicrocephaly, asymmetric severe micrognathia, large ears, atrioventricular septal defect, vertebral anomalies, bilateral cutaneous syndactyly of fingers and toes, unilateral cryptorchidism and multiple café-au-lait spots. The mother of the propositus has multiple café-au-lait spots. Search of POSSUM and the London Dysmorphology Database (LDDB) uncovered no similar case. We think that this patient represents a new acrocraniofacial dysostosis syndrome.

Further study of strontium selenite and selenite F broths for the isolation of Salmonella typhi.

The efficiency of strontium selenite and selenite F broths in the isolation of S. typhi from 625 clinical stool specimens were compared. A total of 126 strains of S. typhi were detected. Of these, 96 (76%) were isolated with selenite F broth and 118 (94%) were isolated with strontium selenite broth. At the same time, the number of false positive isolates accruing to strontium selenite broth was less than that accruing to selenite F broth. The superiority of strontium selenite broth over selenite F broth was more obvious when relatively few typhoid bacilli were present in faeces, eg, after antibiotic therapy, or when stools had been left for prolonged periods at room termperature. In the isolation of S. typhi with strontium selenite broth, salmonella-shigella agar was found to be a better plating medium than xylose lysine desoxycholate agar.

Role of xanthine oxidase in reperfusion injury of ischemic skeletal muscles in the pig and human.

We investigated whether xanthine oxidase (XO) is a major source of oxygen-derived free radicals (oxy-radicals) in the pig and human skeletal muscles. It was observed that xanthine dehydrogenase and XO activities in nonischemic pig latissimus dorsi (LD) and gracilis muscles and human LD and rectus abdominis (RA) muscles were < 0.5 mU/g wet wt. The pig LD muscle hypoxanthine content increased significantly from 0.33 +/- 0.02 to 2.33 +/- 0.44 mumol/g dry wt after 5 h of warm ischemia, but the muscle uric acid content remained unchanged up to 2 h of reperfusion. Similarly, the hypoxanthine content in the human LD and RA muscles increased from 0.33 +/- 0.03 to 0.84 +/- 0.23 mumol/g dry wt after 2.0-3.5 h of warm ischemia, and the muscle uric acid content remained unchanged at the end of 15-90 min of reperfusion. Furthermore, 5 days of allopurinol treatment (25 mg/kg iv twice daily) starting 2 days before ischemia or 3 days of oxypurinol treatment (25 mg/kg iv twice daily) starting 15 min before reperfusion did not attenuate the extent of skeletal muscle necrosis in pig LD muscles subjected to 5 h of ischemia and 48 h of reperfusion. However, deferoxamine treatment (250 mg/kg iv twice daily) starting before or after ischemia, as described above, significantly reduced the extent of pig LD muscle necrosis. Finally, at 2 and 48 h of reperfusion significantly higher muscle neutrophil contents were seen in ischemic than in nonischemic control pig LD muscles. Neutrophil depletion with mechlorethamine (0.75 mg/kg iv) significantly reduced the extent of necrosis in pig LD muscles. These observations indicate that XO is not a major source of oxy-radicals in ischemia/reperfusion injury in the pig gracilis and LD muscles and human RA and LD muscles.

Vascular effects and mechanism of action of endothelin-1 in isolated perfused pig skin.

We investigated the vascular effects and mechanism of action of endothelin-1 (ET-1) in the skin by intra-arterial infusion of ET-1 and its precursor Big ET-1 via a direct cutaneous artery in isolated perfused pig skin flaps (6 x 16 cm). The vascular contractivity was studied by monitoring the perfusion pressure in the skin flap. There was evidence to indicate local conversion of Big ET-1 to ET-1 in the pig skin. It was also observed that ET-1 was a potent long-lasting vasoconstrictor with a potency of approximately 10- and 300-fold higher than those of Big ET-1 and norepinephrine, respectively. The vasoconstrictor action of ET-1 was blocked (P < 0.01) by a selective ETA-receptor antagonist (BQ-123 or BQ-610; 10(-7) M) and enhanced (P < 0.05) by a nitric oxide synthase inhibitor (NG-monomethyl-L-arginine or N omega-nitro-L-arginine methyl ester; 10(-5) M). ET-1-induced increase in perfusion pressure was attenuated (P < 0.05) by an L-type Ca(2+)-channel antagonist (nitrendipine, verapamil, or nifedipine; 10(-5) M) and by removal of Ca2+ from the perfusate. ET-1-induced increase in perfusion pressure was also attenuated (P < 0.05) by a phospholipase C inhibitor (neomycin; 10(-2) M), a protein kinase C (PKC) inhibitor (chelerythrine or H-7; 10(-5) M), and an intracellular Ca2+ chelator [1,2-bis(2-aminophenoxy)]ethane-N,N,N',N'-tetraacetic acid (BAPTA); 10(-5) M]. Furthermore, it was observed that the concentration-dependent (5 x 10(-8) to 10(-5) M) increase in perfusion pressure induced by phorbol 12,13-dibutyrate, a PKC activator, was not affected by verapamil (10(-5) M) or removal of Ca2+ from the perfusate. Taken together, these observations suggest that the vasoconstrictor mechanism of ET-1 in the pig skin involved activation of ETA receptors, L-type Ca2+ channels, phospholipase C, and PKC and that the vasoconstrictor effect caused by activation of PKC was independent of L-type Ca2+ channels.

Current concepts in the use of bone grafts in facial fractures. Basic science considerations.

In choosing the ideal donor site for bone replacement, attention must be given to the recipient site's revascularization potential and mechanical needs. Based on histologic differences in architecture as related to these two factors, the most appropriate graft type may be harvested. Future potential exists for bone replacement by distraction osteogenesis without the need for remote site harvesting. This may provide for the most identical bone replacement.

Application of minimal-access techniques in lag screw fixation of fractures of the anterior mandible.

A modification of the traditional open methods for the surgical management of anterior mandibular fractures using the principles of minimal-access surgery is presented; it was successfully performed in five patients. This technique incorporates the use of lag screws introduced through small incisions transmucosally or percutaneously after anatomic reduction of the fracture, and it relies on accurate preoperative radiologic assessment of the fracture pattern and location. This technique is indicated for any favorable fracture in the anterior mandibular arch that could achieve osteosynthesis with lag screw fixation, and it depends on the use of a dental arch bar as a tension band. Contraindications include unfavorable fracture patterns (long oblique, comminuted, or flat mandibular plane), inadequate dental support to maintain an arch bar due to missing or loose teeth, the inability to determine the fracture pattern preoperatively, and operator inexperience. Potential advantages include a shorter operative time, economic savings, decreased patient morbidity (swelling, scarring, and mental nerve and lower-lip muscle dysfunction), and improvement in functional rehabilitation.

Cranioplasty: indications, technique, and early results of autogenous split skull cranial vault reconstruction.

Since 1990, fresh autogenous split skull cranioplasty has been the preferred method of reconstructing complicated cranial defects at the Sunnybrook Hospital. Eight cases of split skull cranioplasties were reviewed to illustrate the indications and technical considerations of the procedure. Clinical factors believed to be detrimental to the outcome of split skull cranioplasty were identified by: 1) a history of an infected, failed, previous cranial reconstruction, 2) inadequate scalp or skin to cover the external surface of an anticipated skeletal vault reconstruction, 3) the communication of adjacent paranasal sinuses with the epidural space, 4) the presence of an avascular dead space posterior to the reconstructed cranium. These potentially negative influences were systematically addressed as part of the surgical routine in autogenous split skull cranioplasty.

Intraocular and intraorbital compartment pressure changes following orbital bone grafting: a clinical and laboratory study.

Visual loss is an uncommon but catastrophic complication after intraorbital bone grafting for the reconstruction of acute traumatic defects or long-standing enophthalmos. Increased intraocular or intraorbital compartment pressure may be pathogenic in this setting. A two-part study was designed to test the null hypothesis that intraocular and intraorbital compartment pressure values remain constant despite orbital volume reduction with graft material. Laboratory study: Intraocular and intraorbital compartment pressures were measured during sequential orbital volume reduction in New Zealand White rabbits that had been randomized to one of three groups: intact orbits (n = 10), acute orbital wall defects (n = 8), and chronic (3 months) orbital wall defects (n = 11). Intraocular pressure was significantly (p<0.05) elevated in all three groups of orbits undergoing orbital volume reduction compared with control, nonoperated orbits. Intraorbital compartment pressure values did not change significantly from control levels throughout the grafting sequence. Although no significant differences existed between groups in the maximum levels of intraocular pressure attained, the chronic group demonstrated a greater rate of rise and slower rate of decline. Clinical study: Using applanation tonometry, intraocular pressure was measured before and serially after orbital floor exploration and intraorbital placement of split calvarial bone grafts in 19 patients who presented with orbital-zygomatic complex fractures that required surgery. A separate group of 16 patients with orbital-zygomatic complex fractures that required exploration of the orbital floor but not bone grafting was used for comparison. A significant (p<0.05) elevation of intraocular pressure was observed immediately after bone grafting compared with nongrafted orbits, but values returned to normal within 30 minutes and remained stable through the third postoperative day. There were no cases of visual impairment in any patients in either group as the result of surgical treatment. These data indicate that orbital volume reduction with graft material results in significant, temporary elevation of intraocular pressure. No significant elevations of intraorbital compartment pressure were detected in the rabbit orbits. Data from this study may have direct relevance in defining guidelines for "tolerable" changes in orbital tissue and globe pressures after surgery.