Craig D. Friedman

Experimental hydroxyapatite cement cranioplasty.

Hydroxyapatite cement is a calcium phosphate-based material that when mixed with water forms a dense paste that sets within 15 minutes and isothermically converts in vivo to a microporous hydroxyapatite implant. This cement was used to reconstruct bilateral 2.5-cm-diameter full-thickness critical-sized parietal skull defects in six cats. One side was reconstructed with 100 percent hydroxyapatite cement, and the other with a mixture of 50 percent hydroxyapatite cement and 50 percent ground autogenous bone by weight. These animals were sacrificed at 6 and 12 months after implantation. Positive and negative controls also were prepared. The anatomic contour of the soft tissue overlying all hydroxyapatite cement implants was well maintained, there were no wound infections or structural failures, and the implants were well tolerated histologically. None of the negative (unreconstructed) control defects was completely filled with repair bone, and all positive (methyl methacrylate) controls demonstrated foreign-body giant-cell formation and fibrous encapsulation of the implants. Examination of decalcified and undecalcified sections revealed progressive but variable replacement of the cement by new bone and soft tissue without a change in the shape or volume of the hydroxyapatite cement-reconstructed areas. New bone comprised 77.3 and 64.7 percent of the tissue replacing the hydroxyapatite cement and hydroxyapatite cement-bone implants, respectively. Replacement of the hydroxyapatite cement implants by new bone is postulated to occur by a combination of osteoconduction and implant resorption. These results indicate that further experimental research leading to the possible application of hydroxyapatite cement for full-thickness calvarial defect reconstruction in humans is warranted.

Primary extracranial meningiomas of the head and neck.

Extracranial meningiomas comprise approximately 2% of all meningiomas. Primary extracranial meningiomas are even less common. This report details our experience with these unusual tumors from 1972 to 1989. The diagnosis, surgical management, and significant histopathologic features are discussed. The correlation of primary extracranial meningiomas with neurofibromatosis type II and a treatment algorithm are presented.

Longitudinal voice quality changes following isshiki thyroplasty type I: The yale experience†

Longitudinal voice quality changes following Isshiki thyroplasty type I were investigated in a group of 18 patients exhibiting unilateral vocal fold paralysis. Thyroplasty type I medializes the paralyzed fold by using a Silastic® implant for external lateral compression of the abducted fold. No perioperative complications were experienced. We observed significantly higher voice fundamental frequency, significantly louder voice intensity, and significantly longer maximum phonation time, both immediately following phono‐surgery and up to 3 months postoperatively. Surgical refinements of thyroplasty type I are described.

Reconstruction of suboccipital craniectomy defects with hydroxyapatite cement: A preliminary report

Hydroxyapatite cement, a new biomaterial presently under clinical investigation, has been demonstrated to have potentially wide application in cranial reconstruction. We describe our experience with this biologic bone cement in the reconstruction of suboccipital craniectomy defects in seven patients after vestibular schwannoma removal. With up to 2‐year follow‐up, cranial bone integrity has been reestablished in five patients. Dissolution of cement has occurred in dependent areas and appears to be technique related. Cranial bone contour appears dependent on the amount of cement used. The frequency of debilitating postoperative headache was reduced in these patients when compared to patients who had no reconstruction of the craniectomy defect. Reconstruction of the bony defect after suboccipital craniectomy with hydroxypatite cement is not only useful to restore cranial contour, but also appears to reduce some of the functional deficits attributed to this surgical approach.

Le fort i osteotomy approach to the skull base

Horizontal osteotomy allows the surgeon to safely down‐fracture the maxilla for wide exposure of the central skull base. This surgical approach is easily extended posteriorly in the midline to include the clivus and the arch of C1, providing 8 cm of horizontal anterior exposure and 5 cm of posterior. Wide operative exposure and a low rate of complications afford superior functional and cosmetic preservation in removing tumors of the central cranial base.

Experimental Tracheal Replacement Using a Revascularized Jejunal Autograft with an Implantable Dacron Mesh Tube

Defects comprising more than 50% of the trachea cannot be reliably reconstructed by any current technique or prosthesis. A composite tracheal replacement implant consisting of a Dacron-urethane mesh tube and revascularized jejunal autograft was applied to this problem. This composite implant was used to replace 7 to 10 cm of trachea in eight dogs. The implant was sewn to the outside (serosal surface) of the jejunum to provide permanent structural support to the autograft, and an intraluminal silicone tube was placed inside the jejunal segment and left for 4 weeks following reconstruction. Six of eight animals survived the predetermined time periods and were killed painlessly in groups of two animals at 1, 2, and 6 months after removal of the intraluminal silicone tube. Postoperative intubation, ventilation, or tracheostomy was not necessary. Excessive secretions were not seen in any of the animals, and a fair to good performance status was maintained until death in all but one animal. Histologic examination revealed slight thinning of the jejunal mucosa, with no change in the jejunal muscularis. These data suggest that with further refinement this composite implant may be a viable reconstructive option in humans.

HIV-Associated Facial Lipoatrophy: Establishment of a Validated Grading Scale

Objective: HIV‐associated lipodystrophy is considered a sequela of highly active antiretroviral treatment. We describe the characteristics, possible etiology, and pathophysiology of HIV‐associated lipodystrophy and facial lipoatrophy and establish a validated grading scale for HIV‐associated facial lipoatrophy using evidence‐based techniques.

A Population-based Trial of β-Carotene Chemoprevention of Head and Neck Cancer

Squamous cell carcinoma (SCC) of the upper aerodigestive tract (oral cavity, pharynx, and larynx) is a major health problem in the United States and throughout the world. It is estimated that 43,300 new cases will be identified and that 11,800 patients will die of these cancers in the United States in 1991 (1). In addition to the number of patients affected, cancers of the oral cavity, pharynx, and larynx assume a higher relative importance because of the functional impairment and cosmetic deformity associated with the cancer and its treatment.

Prevention of cerebrospinal fluid rhinorrhea in neurotologic surgery

OBJECTIVE To determine the efficacy and safety of quick-setting hydroxyapatite cement in eliminating cerebrospinal fluid (CSF) rhinorrhea following neurotologic surgery. STUDY DESIGN A prospective study of 40 consecutive patients undergoing neurotologic surgery in whom the dura was opened. SETTING All patients were treated as hospital inpatients at a tertiary referral center. PATIENTS 25 men and 15 women between the ages of 20 and 72 years (mean age 51 years) underwent neurotologic surgery at the parent institution. INTERVENTION Various neurotologic procedures were performed for the resection of 25 acoustic tumors, 5 meningiomas, 3 glomus tumors, 2 vestibular nerve sections, 2 chordomas, 1 epidermoid tumor, and 1 meningoencephelocele, and for 2 patients referred to our institution with known CSF leaks following acoustic tumor surgery. A new form of quick-setting hydroxyapatite cement, which that hardens within 3 to 5 minutes was used to seal the air cell tracts of the temporal bone in all cases. MAIN OUTCOME MEASURE The presence of CSF rhinorrhea postoperatively. RESULTS CSF rhinorrhea occurred in 2 patients following acoustic tumor surgery, the first through an occult air cell tract at the margin of the drilled internal auditory canal, and the second via an oval window fistula 1 month after a translabyrinthine approach. CONCLUSIONS This form of hydroxyapatite cement appears safe, reliable, effective, and economical for the prevention of CSF rhinorrhea following neurotologic surgery. CSF rhinorrhea cannot be eliminated unless our ability to identify all potential air cell tract communications improves.

Synthetic Biomaterials in Facial Plastic and Reconstructive Surgery

Educational objectives: To understand the general principles of biocompatability along with the effect that a synthetic implant has on would healing and to appropriately match an implant to its proposed site of implantation and be familiar with those implants currently approved for use in the United States.