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Biomedical subjects

Alan S Herford

Publications and source records attributed to Alan S Herford.

12 recordsLinked to original sources
PubMed2005

A comparison of synovial fluid pressure after immediate versus gradual mandibular advancement in the miniature pig.

PURPOSE: Mandibular advancement is a commonly performed surgical procedure for the treatment of mandibular hypoplasia. With the increased use of rigid fixation, there has been a decrease in the amount of relapse but an increase in the amount of force transmitted to the condyles. Gradual advancement of the mandible by distraction osteogenesis slowly overcomes the soft-tissue envelope and may decrease the amount of force exerted on the condyles. The purpose of this study was to develop an animal model to measure the magnitude of pressure associated with immediate versus gradual mandibular advancement. MATERIALS AND METHODS: A 2.0-mm pressure transducer was placed in the superior joint space in 2 miniature pigs. In the first animal, immediate advancement of the mandible with rigid fixation was performed. The synovial fluid hydrostatic pressures were measured prior to surgery and postoperatively. A second animal underwent gradual advancement with distraction osteogenesis. The synovial fluid hydrostatic pressures were measured prior to and after each activation of the distraction device. The condyles were examined radiographically and microscopically. RESULTS: The superior joint space fluid pressures increased and remained elevated over a 5-week period after immediate advancement. In the gradually advanced mandible, the pressures were elevated but returned to near baseline prior to the activation the following day. CONCLUSION: This animal model is useful to directly measure the pressure that is exerted on the condyle. This will allow further studies to compare methods for mandibular advancement. It is likely that gradual advancement of the mandible by distraction osteogenesis produces less force and causes less condylar resorption than large mandibular advancement stabilized with rigid fixation.

Animals↗
PubMed2005

Outcomes of severely comminuted (type III) nasoorbitoethmoid fractures.

PURPOSE: Nasoorbitoethmoid (NOE) fractures are complex and often challenging to repair. Inadequate treatment may result in secondary deformities which are difficult to treat. Severely comminuted fractures require repositioning of the medial canthal tendon. The purpose of this study was to evaluate all results in treating these challenging injuries. The work is to be used as a basis for continuing quality improvement of our surgical technique. PATIENTS AND METHODS: [corrected] Ten consecutive patients who sustained a comminuted NOE (type III) fracture were included in this study. All patients had comminution of the central fragment involving the detachment of the medial canthus. RESULTS: Transnasal reduction, primary grafting, and plate and screw fixation were used for all patients. Two patients demonstrated slight asymmetry between the medial canthi. Two patients were observed to have overprojection in the nasofrontal region. CONCLUSION: Severely comminuted type III NOE fractures are best treated primarily to avoid secondary deformities.

Bone Plates↗
PubMed2005

Distraction osteogensis: a surgical option for restoring missing tissue in the anterior esthetic zone.

Common causes of alveolar defects include bone resorption due to loss of teeth, infection, or trauma. There is often insufficient height or width of residual bone, and ridge augmentation may be required prior to implant placement. These defects range from small alveolar deficiencies to more complex, extensive bony defects. Various techniques are available for reconstructing alveolar ridges. Without augmentation, dental implants may have to be placed in anatomically unfavorable positions or have adverse angulations. These position/angulation compromises can lead to esthetic dissatisfaction, mechanical overload, and possibly implant loss. Both bone grafting and distraction osteogenesis are predictable methods for restoring missing tissue.

Adolescent↗
PubMed2004

Use of a plate-guided distraction device for transport distraction osteogenesis of the mandible.

BACKGROUND: Transport distraction osteogenesis has been used to reconstruct continuity defects by regenerating bone and soft tissues. A challenge has been to maintain the correct vector during the distraction process. A new type of distraction device was recently developed that uses a standard reconstruction plate to "guide" the transported segment of the bone. This plate-guided distractor device (PGD) intimately follows the shape of the plate, thus allowing for 3-dimensional vector control during the distraction process. PATIENTS AND METHODS: Four patients underwent transport distraction osteogenesis for reconstruction of segmental mandibular defects ranging in size from 4 to 7 cm. The age of the patients ranged from 27 to 62 years. Two patients had been treated with radiotherapy as part of treatment for oral malignancy. A standard locking reconstruction plate was placed to bridge the continuity gap. An osteotomy was performed to create a bone transport segment. The PGD was secured to both the reconstruction plate and the transport bone. After a latency period of 7 days, the device was activated at a rate of 1 mm/d. The distraction process continued until the transport segment reached the opposing bone or sufficient bone and soft tissue were reconstructed for oral rehabilitation. RESULTS: All patients achieved hard and soft tissue formation. Two patients had premature consolidation of the distraction regenerate but had sufficient tissue for rehabilitation. CONCLUSION: A PGD can be used to regenerate missing hard and soft tissues. An advantage of this technique is that it uses a reconstruction plate that is routinely placed to bridge mandibular continuity defects. This device allows for ultimate vector control by intimately following a carefully adapted plate.

Adult↗
PubMed2004

Early repair of avulsive facial wounds secondary to trauma using interpolation flaps.

PURPOSE: This article describes the use of various local interpolation flaps for the reconstruction of facial defects resulting from trauma. PATIENTS AND METHODS: Fifteen interpolation flaps were used to restore missing tissue of 14 patients who sustained trauma. Two of the procedures were performed as a single stage, whereas 13 flaps required a separate surgery to "take down" the pedicle. All flap procedures were performed within 72 hours from the time of trauma. Four types of interpolation flaps were used. RESULTS: All flaps healed without evidence of infection, dehiscence, or necrosis. Two patients required secondary treatment 6 months after the flap procedure. CONCLUSION: Various local interpolation flaps provide a reliable and aesthetic treatment option for early repair of soft tissue defects secondary to trauma.

Accidents, Traffic↗
PubMed2004

Dorsal nasal reconstruction using bone harvested from the mandible.

PURPOSE: This article describes a technique for reconstructing nasal deformities resulting from trauma. Bone harvested from the lateral ramus/body of the mandible is used to provide nasal support for major nasal deformities. PATIENTS AND METHODS: Ten patients underwent repair of their nasal deformities with an autogenous bone graft harvested from the mandible. Primary bone grafting was used to repair a nasal deformity associated with a naso-orbito-ethmoidal fracture in 8 patients. Secondarily, 2 patients underwent placement of a graft for correction of a saddle nose deformity. RESULTS: All patients achieved aesthetic results. There was maintenance of nasal projection and symmetry without displacement of the graft. None of the patients complained of an unnatural hardness of the nasal tip or dorsum. All grafts healed without evidence of infection, dehiscence, or necrosis. CONCLUSION: The lateral ramus/body of the mandible provide an excellent donor site alternative for nasal reconstruction.

Bone Transplantation↗
PubMed2004

Distraction osteogenesis of the nasal and antral osseous floor to enhance alveolar height.

PURPOSE: The purpose of the study was to obtain information on the possibility of using distraction osteogenesis (DO) to increase the height of posterior atrophic maxillary alveolar ridges by distracting very small alveolar crest bone segments and, secondly, to determine if it is possible to distract the bony antral floor itself, producing new bone between the sinus membrane and the alveolar crest. MATERIALS AND METHODS: Three adult Papio anubis baboons were rendered edentulous in the posterior maxilla. Bilateral osteotomies were performed to produce a thin margin of crestal alveolar bone and in one area, a complete exposure of the antral floor. Distractors were placed against the antral and nasal floors and the thin 1- x 1.5-mm thick alveolar bone crest was distracted 10 mm over a period of 10 days. Animals were labeled with tetracycline at 3 and 4 months and were sacrificed at 5 months. RESULTS: A complete osseous regeneration of the nasal floor and alveolar ridge greater than 10 mm in height was produced in all cases. Histomorphometric analysis of the DO-induced osseous areas revealed cancellous bone with increasing thickness during the third and fourth month and formation of new bone cortices increasing in thickness during the same time. Significant new bone also formed in the antral floor areas that had been purposely interdicted by the osteotomies. CONCLUSION: The results of this study indicate that very small segments of bone of the posterior maxilla can be distracted to produce significant increases in the alveolar bone height and that a new osseous nasal-antral floor enhancement can be produced by this technique.

Alveolar Ridge Augmentation↗
PubMed2003

Ankylosis of the jaw in a patient with fibrodysplasia ossificans progressiva.

A case of fibrodysplasia ossificans progressiva (FOP) is presented. This uncommon connective tissue disease tends to produce progressing ectopic osteogenesis. Because there are no reported curative procedures for TMJ ankylosis occurring in this condition, a palliative surgical approach is described. Etiology, diagnosis, and prognosis of the disease is reviewed. Recent research in BMP cytokine-induced bone repair may allow new approaches to treating this debilitating disease in the future.

Adult↗
PubMed2003

Medial approach for tibial bone graft: anatomic study and clinical technique.

PURPOSE: The purpose of this study is to quantify the amount of bone graft material present in the proximal tibia via a lateral versus a medial approach, as well as describe an alternative technique for obtaining this bone graft material. A quantitative anatomic and statistical analysis and comparison are presented. The goal of this study is to demonstrate the advantages and simplicity associated with utilizing the proximal tibia as a bone graft harvest site in oral and maxillofacial surgery via a medial approach. MATERIAL AND METHODS: Forty lower extremities from 20 cadavers were studied. All specimens were dissected, and anatomic landmarks were recorded. Anatomic structures, including vessels, nerves, muscle attachments, articular surfaces, and their relationships to various anatomic landmarks were identified, measured with a linear millimeter ruler, and recorded. Bone harvest was accomplished using either a medial (20 extremities) or lateral (20 extremities) approach. The amount of bone available for harvest using both techniques was compared. Variables evaluated included volume of graft, age, gender, and relationships among anatomic structures. RESULTS: The mean volume of bone harvested was 25.0 mL for the lateral approach and 24.9 mL for the medial approach (range, 14 to 34 mL). The Mann-Whitney U test revealed no significant difference in mean volume of graft obtained when comparing the medial and lateral approaches (P =.9250). Pearson's correlation test revealed no correlation between age (P =.089 medial and P =.174 lateral) or gender (P =.3120 medial and P =.4440 lateral). The lateral anatomic structures evaluated included the anterior tibial vessels that emerged from the interosseous hiatus 14.3 mm inferior to tibial perpendicular and 42.6 mm lateral to the tibial parallel line. The distance from the tibial perpendicular to the articular surface did not significantly differ when comparing the medial (33.65 mm) and lateral (33.25 mm) anterior tibial surfaces. The mean length of the oblique line was 17.9 mm, and the superior portion of this line was 14.65 mm above the tibial perpendicular line. CONCLUSIONS: Equal amounts of bone graft material are available for harvest from the medial and lateral aspects of the proximal tibia. Knowledge of important anatomic landmarks can be used preoperatively to allow for safe dissection and harvest of autogenous bone from the proximal tibia. The dissection of medial proximal tibia and harvest of bone graft material may be accomplished efficiently with minimal chances of damage or morbidity to vital adjacent structures.

Adult↗
PubMed2002

Tracheotomy versus endotracheal intubation for airway management in deep neck space infections.

PURPOSE: The aim of the present study was to compare costs and outcomes for patients with deep neck infections who were treated with either tracheotomy or endotracheal intubation. MATERIALS AND METHODS: The charts of 85 patients with deep neck space infections were retrospectively studied. Requirements for inclusion in the study were incision and drainage in the operating room, involvement of more than 1 deep anatomic space, impending airway compromise, and maintenance of a postoperative artificial airway. The 85 patients were divided into 2 groups based on the type of airway used for treatment. Group 1 (n = 34) included patients who received a tracheotomy, and group 2 (n = 51) included patients whose airways were maintained with endotracheal intubation until the swelling had resolved sufficiently for extubation. RESULTS: Patients in group 1 had a shorter overall hospital stay (4.8 vs 5.9 days, NS) and spent less time in the intensive care unit (1.1 vs 3.1 days, P <.05). The overall incidence of complications was 6% for group 1 and 10% for group 2. The rate of complications secondary to loss of airway was 3% for group 1 and 6% for group 2. Average costs associated with intensive care resources were 5 times greater and overall hospital stay costs were 60% greater for group 2. CONCLUSIONS: Although both methods of airway control are useful and have a unique set of complications, the use of tracheotomy allowed earlier movement to a noncritical care unit and was associated with fewer intensive care costs and less overall cost of hospitalization. Tracheotomy may therefore provide better utilization of critical care resources in this group of patients.

Adult↗
PubMedDate not supplied

Maintaining vector control during alveolar distraction osteogenesis: a technical note.

Distraction osteogenesis is a predictable method for restoring missing tissue prior to implant placement. However, pull from the soft tissue can alter the desired direction of the distraction. This article describes and illustrates techniques that are useful for maintaining the desired vector during alveolar distraction osteogenesis. These methods can prevent the need for further intervention and allow for ideal placement of endosseous dental implants without compromising results.

Alveoloplasty↗