Richard Finn

Interpositional “Grafting” with autogenous bone and coralline hydroxyapatite

Summary The lack of bone mass associated with relatively high muscle attachments and insufficient vestibular depth complicates the prosthetic restoration of the atrophic mandibular alveolar ridge. Alloplasts and autogenous bone grafts have been used to augment the atrophic alveolar ridge with variable results. Onlay bone grafts tend to resorb while alloplastics may become infected and resorb underlying bone. The concept of interpositional bone grafting has certain theoretical advantages. It has been postulated that preservation of the integrity of the mucosa-periosteum-cortex relationship of the repositioned bone and maintenance of its morphological form and osseous architecture will minimize resorption of the transposed basal bone. An animal study was designed to test the validity of this concept. The vascularization, revascularization, and bone healing associated with interpositional autogenous bone grafts and implants of coralline hydroxyapatite were investigated in nine adult mongrel dogs. The mandibular posterior teeth were extracted and an enbloc resection of the alveolar bone which encased the extracted teeth was accomplished to simulate mandibular atrophy. Eight weeks later through an intraoral approach an autogenous cortico-cancellous iliac bone graft was placed in the edentulous area; a 2 cm. × 1 cm. × 1 cm. hydroxyapatite implant was placed on the contralateral side. The animals were sacrificed immediately, at 3 days, and 1, 2, 4, 12, 24, 28, and 40 weeks. Radiographic, microangiographic, and histological studies indicated that the lingual mucoperiosteum in the mandible provided an adequate vascular pedicle for superior repositioning of mandibular basal bone in a single stage. There was early consolidation and remodelling of the grafted bone and implant with minimal alteration of the morphological form and architecture of the repositioned bone. The results of this animal study support the concept of interpositional bone grafting to augment the atrophic mandibular alveolar ridge. The promise of coralline hydroxyapatite was favourable and awaits further ongoing comparative studies with bone grafts.

Mandibular subluxation for high carotid exposure

Twenty-four patients with internal carotid artery lesions extending above the second cervical vertebra underwent mandibular subluxation for additional exposure. The original technique of bilateral arch bar wiring requiring 90 minutes for application has evolved into a circummandibular/transnasal wiring technique requiring approximately 10 minutes. Subluxation of the mandibular condyle 10 to 15 mm anteriorly results in displacement of the mandibular ramus 20 to 30 mm anteriorly. This technique provides a marked increase in exposure of the internal carotid artery up to the base of the skull by transforming a triangular operating field into a rectangular field. The technique is quick, easy to perform, and not associated with objective or subjective temporomandibular joint dysfunction.

Long-term clinical outcome analysis of poly-methyl-methacrylate cranioplasty for large skull defects

PURPOSE The goal of secondary cranioplasty is permanent cerebral protection in an esthetically acceptable fashion. Reconstruction of cranial defects can be performed with several different materials. Alloplastic materials, such as preformed methyl-methacrylate (PMMA) cranioplasties, are an alternative frequently used at our institution. This retrospective analysis was designed to review the outcomes of PMMA cranioplasty for skull defect reconstruction. MATERIALS AND METHODS Seventy consecutive patients who had 78 PMMA cranioplasties placed from 2003 through 2010 were identified. Mechanism of injury, location of cranioplasty, type of original repair, postoperative complications, and follow-up time were reviewed. RESULTS Of the 70 patients, 6 patients had failure and removal of their original PMMA cranioplasty and reinsertion of another, and 2 patients had failure and removal of 2 cranioplasties with replacement of a third, creating a total of 78 PMMA cranioplasties placed. The predominant mechanism of injury was trauma (64%). The most frequent postoperative complication was infection (13%). With the exception of the 2 patients with implant exposure, no patients reported an unacceptable cosmetic result. An overall complication rate of 24% was seen. CONCLUSIONS The results of previous studies have shown that infection and complication rates of cranioplasties accomplished with bone cement are substantially higher, that titanium-based implants may obscure follow-up imaging for tumor patients, and that the outcomes regarding hydroxyapatite-based ceramics, although similar to PMMA, are associated with a much higher cost. PMMA remains a cost-effective and proven method to repair cranial defects that fulfills the goals of cranial reconstruction for skull defects.

Wound healing associated with segmental total maxillary osteotomy.

A technique that maintains dual soft tissue pedicles to the palatal and labiobuccal areas in segmental total maxillary osteotomy was studied with respect to the effects on osseous revascularization and healing. Single-stage four-segment total maxillary osteotomies were performed by this method in five adult male rhesus monkeys. The animals were killed at intervals from immediately to 28 days after surgery. Histologic examination of the maxillae revealed that this technique is sufficient to support total maxillary osteotomy through 28 days. The soft tissue flap provided adequate blood supply to the anterior maxillary segment. All bony segments were mobilized, with only transient effects on bone healing and viability. The marginal osteonecrosis observed did not appear to be progressive. The effects of this procedure on the pulp are not clear.

Muscular rehabilitation after orthognathic surgery

There is both a biologic and a clinical foundation for the use of therapeutic exercise after othognathic surgical procedures to restore normal function of the jaw muscles. This can be accomplished by a systematic plan Of occlusal and muscular rehabilitation after release of maxillomandibular fixation. Through the diligent application of physical therapy principles, the function of the masticatory muscles can be more efficiently rehabilitated after orthognathic surgery and maxillomandibular fixation.

Wound healing after multisegmental le fort i osteotomy and transection of the descending palatine vessels

PURPOSE Vascular ischemia has been associated with improper soft tissue flap design, stretching of the palatal vascular pedicle, bony segmentation, transection of the descending palatal vessels, or hypotension. This study examined Le Fort I osteotomy wound healing after some of these surgical maneuvers. MATERIALS AND METHODS Clinically analogous four-segment Le Fort I osteotomies were accomplished through circumvestibular incisions in nine adult rhesus monkeys and the animals were killed at 0, 3, 7, 14, and 28 days after surgery. Revascularization and bone healing were studied by microangiographic and histologic techniques. RESULTS The findings indicated that the palatal mucosa or labial-buccal gingiva and mucosa provide adequate nutrient pedicles for Le Fort I osteotomies accomplished through a circumvestibular type incision. CONCLUSIONS It was concluded that segmentalization, stretching of the vascular pedicles, or transection of the descending palatine vessels have only transitory discernible effects on revascularization and bone healing.

Mucormycosis of the mandible

A case of mucormycosis of the mandible and adjacent soft tissue is presented. The rampant osteomyelitis that developed over a two-month period shows the necessity of early medical and surgical intervention. The management of these patients includes aggressive medical management of underlying problems, high-dose amphotericin B administration, and early surgical debridement of all involved tissues.

Anatomical variation of the nasal septum: Analysis of 57 cadaver specimens

Objectives The purpose of this study was to examine the anatomical variation of the osseous and cartilaginous components of the nasal septum. Study Design Fifty-seven cadaver specimens were digitally scanned and analyzed utilizing Bersoft Image software. Anatomical data were statistically analyzed utilizing SPSS 13.0. Evaluation of the area of the osseous/cartilaginous nasal septum as well as an estimation of the available cartilage for grafting was performed. Results Septal specimens revealed males had greater variation in cartilaginous area compared to female specimens. The intranasal/extranasal cartilage contributes about 45%/55% of the total cartilage, respectively. The data indicate that the mean area of cartilage available for grafting is around 420 mm2. Conclusions Significant variability in the cartilaginous elements of the nose is the rule rather than the exception. Key differences exist in the anatomic location of the graft material between males and females. This has important surgical implications given the critical attention required during graft harvesting in order to maintain support of the nose.

Prolonged Recovery Associated With Dexmedetomidine When Used as a Sole Sedative Agent in Office-Based Oral and Maxillofacial Surgery Procedures

PURPOSE Office-based oral and maxillofacial surgical procedures that require sedation are popular. Dexmedetomidine has the advantages of having a minimal effect on respiration and an antisialogogue effect that could make it a good choice for dental procedures. MATERIALS AND METHODS We performed a prospective pilot study in which patients undergoing office-based oral and maxillofacial surgical procedures received dexmedetomidine as a sole sedative agent. The loading dose of dexmedetomidine (1 microg/kg infused over 10 minutes) was followed by a maintenance dose (0.2 to 0.8 microg/kg/hour) to achieve a Ramsay sedation score of 2 to 3. The demographic data were collected, and the pre- and intraprocedural vital signs and Ramsay sedation score were recorded every 5 minutes. The duration of the procedure, recovery time, and patient and surgeon satisfaction were documented. RESULTS No statistically significant changes were found in the heart rate, respiratory rate, or oxygen saturation during the procedure when compared to baseline. However, we noticed a significant decrease in the heart rate at the end of the loading dose, and statistically significant change in the blood pressure between baseline and during the procedure (P < .05). The initial local anesthetic injections were recalled by 26% of the patients, and 73% had some recollection of the procedure. Nevertheless, the patient satisfaction score (range 1 to 10) was 8.6 +/- 2.3, and 86% of the patients would recommend this type of sedation. The surgeon satisfaction score (range, 1 to 5) was 3.9 +/- 1.3. The recovery time was prolonged (82.2 +/- 24.3 minutes) when compared with the total procedure time (44.6 +/- 27.9 minutes). CONCLUSIONS Dexmedetomidine has demonstrated hemodynamic and respiratory stability when used as a sole sedative agent. Despite the discomfort on injection and the lack of reliable amnesic property, patient and surgeon satisfaction were high. However, the prolonged recovery time makes this drug unsuitable for busy office-based practices. We believe it should be reserved for patients with a high risk of respiratory complications (eg, obese patients or those with a history of sleep apnea).

Treatment of comminuted mandibular fractures by closed reduction

Few topics concerning the management of mandibular fractures are as controversial as the treatment of comminuted mandibular fractures. A comminuted fracture represents a bone that has been splintered or crushed,’ pulverized,’ or broken into several pieces,” giving rise to many small fragments.“ Thus, for purposes of this discussion, comminution is defined as the presence of multiple fracture lines resulting in many small pieces within the same area of the mandible (ie, angle, body, ramus, symphysis). Analysis of reports involving the number of fractures per mandible demonstrate remarkable consistency, with a range of 1.3 to 1.8 fractures per patient.5 These are obviously not comminuted. Although there has been a rebirth of interest in traumatology as indicated by the plethora of articles in the past 15 years, the incidence of mandibular comminution is still difficult to ascertain. Recent reports on large numbers of mandibular fracture patients (approximately 4,000) have failed to mention either explicitly or implicitly the number or incidence of comminuted mandibular fractures.6-x Other reports imply the presence of comminution, but careful review of the data is equivocal with respect to mandibular comminution, other than use of the term.9,‘0 The spectrum from relatively simple fractures9 to avulsion” seems to be categorized as comminution. However, many large epidemiologic studies”-17 of mandibular fracture patients (approximately 10,800) either do not include or do not mention a category of mandibular comminution. The incidence of mandibular comminution can be carefully and tediously extracted from large series of