Amir Rafii

Computer modeling and intraoperative navigation in maxillofacial surgery

Objectives Recent advances in computer-modeling software allow reconstruction of facial symmetry in a virtual environment. This study evaluates the use of preoperative computer modeling and intraoperative navigation to guide reconstruction of the max-illofacial skeleton. Methods Three patients with traumatic maxillofacial deformities received preoperative, thin-cut axial CT scans. Three-dimensional reconstructions, virtual osteotomies, and bony reductions were performed using MIMICS planning software (Materialise, Ann Arbor, MI). The original and “repaired” virtual datasets were then imported into an intraoperative navigation system and used to guide the surgical repair. Results Postoperative CT scans and photographs reveal excellent correction of enophthalmos to within 1 mm in patient 1, significant improvement in symmetry of the nasoethmoid complex in patient 2, and reconstruction of the zygomaticomaxillary complex location to within 1 mm in patient 3. Conclusion Computer modeling and intraoperative navigation is a relatively new tool that can assist surgeons with reconstruction of the maxillofacial skeleton.

Comparison of 3 Optical Navigation Systems for Computer-Aided Maxillofacial Surgery

OBJECTIVE To compare the accuracy of 3 computer-aided surgery systems for maxillofacial reconstruction. DESIGN Evaluation of 3 computer-aided surgery systems: StealthStation, VectorVision, and Voxim. SETTING The University of California, Davis, Department of Otolaryngology computer-aided surgery laboratory. PARTICIPANTS Four fresh cadaveric heads. MAIN OUTCOME MEASURE Mean target registration error. RESULTS The StealthStation was the most accurate (mean [SD] target registration error, 1.00 [0.04] mm), followed by VectorVision (1.13 [0.05] mm) and then Voxim (1.34 [0.04] mm). All values met statistical significance (P < .05). CONCLUSIONS Measurable accuracy differences were found among the navigation systems evaluated. The StealthStation was the most accurate. However, the differences are small, and the clinical significance for maxillofacial reconstruction is negligible.

Comparison of 4 registration strategies for computer-aided maxillofacial surgery

PURPOSE: Surgeons have recently started to use computer-aided surgery (CAS) to assist with maxillofacial reconstructive surgery. This study evaluates four different CAS registration strategies in the maxillofacial skeleton. MATERIALS AND METHODS: Fifteen fiducial markers were placed on each of four cadaveric heads. Four registration protocols were used: 1) group 1—invasive markers, 2) group 2—skin surface, 3) group 3—bony landmark, 4) group 4—intraoral splint. Two observers registered each head twice with each of the four protocols and measured the target registration error (TRE). The process was repeated on two different navigation systems for confirmation. RESULTS: The mean TRE values were: invasive, 1.13 ± 0.05 mm (P < 0.05); skin, 2.03 ± 0.07 mm (P < 0.05); bone, 3.17 ± 0.10 mm (P < 0.05); and splint, 3.79 ± 0.13 mm (P < 0.05). The TRE values were consistent across CAS systems. CONCLUSION: Of the techniques tested for CAS registration, invasive fiducial markers are the most accurate. Skin surface landmarks, bony landmarks, and an intraoral splint are incrementally less accurate.

Upper and lower eyelid reconstruction: the year in review.

Purpose of reviewDepending on the size, location, and extent of defects, a myriad of surgical approaches may be utilized to repair the eyelids. An understanding of the principles of lid reconstruction as well as orbital and periorbital anatomy is essential when approaching the repair of eyelid defects. While principles of eyelid reconstruction have been established, achieving good functional and aesthetic reconstruction remains challenging. This review examines the methodology of reconstructing eyelid defects, as reported over the last year. Recent findingsEyelid reconstruction continues to encompass a wide range of reconstructive options. Reports range from simple modifications of traditional techniques to the use of complex flaps and grafts. SummaryWhile set algorithms have been proposed regarding eyelid reconstruction, the method of choice will ultimately depend on a combination of factors, including availability of tissues, and a surgeons experience with the available modes of reconstruction.

Advances in scalp reconstruction

Purpose of reviewThe present review summarizes traditional and advanced techniques used to reconstruct defects of the scalp. These deformities range from small defects that can be closed primarily to significant defects, which require free tissue transfer. Recent findingsIncreased use of tissue expanders, advancement rotational flaps, and hair transplantation has resulted in improved cosmetic outcomes for larger defects of the scalp. Free tissue transfer has provided a revolutionary method of reconstructing subtotal and total defects of the scalp, in particular those associated with neoplasms. SummaryNew advances in techniques of scalp reconstruction have provided improved outcomes in terms of cosmetic appearance and decreased morbidity for scalp reconstruction.

Clinical and Genetic Characterization of Frontorhiny Report of 3 Novel Cases and Discussion of the Surgical Management

OBJECTIVES To (1) define the nasal, columellar, and lip deformities of 3 patients with characteristics consistent with frontorhiny; (2) illustrate the embryologic correlation of the oronasal findings to the development of the median nasal prominence; (3) report the clinical manifestation in 3 patients from 2 unrelated families; (4) report a novel Y214X mutation in ALX3 ; and (5) describe the surgical reconstruction. METHODS In this case series, we report 3 novel cases of frontorhiny from 2 different families. The surgical reconstruction technique is reviewed. Extension of the columellar medial crural cartilage into the upper lip cleft is examined histologically. Signed consent was granted for all patient photographs and specimens, and the study was approved by the institutional review committee of the University of California Davis The genetic sequencing of the ALX3 homeobox gene was performed in 2 of our 3 cases using standard commercially available sequencing kits. The genetic material in our third case was not available for analysis. RESULTS Patients 1 and 2 were brothers from the same family. Both exhibited bifidity of their columella, a widened philtrum, poor nasal tip development, and low hairlines. Genetic sequencing in the 2 brothers confirmed the presence of a novel ALX3 homeobox mutation at the second exon (mutation Y214X). Patient 3 was a 4-year-old girl. She presented with an underdeveloped, widened nasal tip and a bifid columella. Her philtrum was widened and had a left-sided cartilaginous prominence. She also had a widened nasal root. Family history revealed no family members with the same features. CONCLUSIONS Frontorhiny represents a new syndromic frontonasal malformation with consistent characteristic features. The genetic abnormality has now been found in 14 different patients. Careful scrutiny and classification of frontonasal deformities will expand our understanding of causes, genetic susceptibility, and treatment options.

08:10: Comparing Registration Strategies for Computer-Aided Surgery

duration of stay, and time of onset of re-bleeding. RESULTS: One patient per 200 tonsillectomies was hospitalized and diagnosed with post-tonsillectomy hemorrhage during the six-year study period. Corresponding figure for re-operations requiring general anesthetics was less than 1 per 1,000 tonsillectomies. The latter group ranged from 8% (2003) to 36% (2000) of all re-hospitalized patients during the study period. The incidence of tonsillectomies increased 36% from 1999, and in-patient treatment became increasingly rarer. While there was in increase in the incidence of post-tonsillectomy bleeding during the study period, the re-bleeding surgery requiring general anesthetics remained stable and was performed in approximately 1 per 1,000 surgeries. CONCLUSIONS: Although posthemorrhage bleeding was rare and re-bleeding surgery applied in only one per thousand surgeries, a slight increase in surgery requiring general anesthetics was noted.

Reversal of longstanding optic neuropathy after resection of a paranasal sinus schwannoma

Abstract Objectives: Schwannomas are benign, slow-growing, peripheral nerve sheath tumors composed of Schwann cells. Nasal and paranasal nerve sheath tumors are rare, consisting of less than 4% of head and neck schwannomas. Paranasal schwannomas tend to expand into the orbit and anterior cranial fossa. The following case demonstrates the reversal of long-standing optic neuropathy after resection of a benign paranasal sinus schwannoma. Methods: We present a 34-year-old woman with right sided nasal obstruction and progressively worsening vision (20/800) in her right eye. MRI revealed a paranasal sinus mass with extension to the anterior cranial fossa, middle cranial fossa, and orbital apex. Results: Endoscopic biopsy of the mass revealed a schwannoma. The mass was resected via a transfacial, subcranial approach to the skull base using image-guided endoscopic assistance. The mass was removed en block and the patient’s vision returned to normal (20/30) within several hours of surgery. Conclusion: This case illustrates the possible reversal of long-standing optic neuropathy following resection of benign paranasal sinus pathology with optic nerve decompression.