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Biomedical subjects

D W Klotch

Publications and source records attributed to D W Klotch.

At least 19 recordsLinked to original sources
PubMed2000

Factors affecting survival for floor-of-mouth carcinoma.

OBJECTIVES: The treatment of extensive floor-of-mouth carcinoma has remained a challenging problem for head and neck surgeons. We have reviewed our experience in the surgical management of floor-of-mouth cancer in an attempt to identify factors influencing survival. METHODS: A total of 144 patients with cancer involving the floor of the mouth were treated between March 1988 and November 1995. A retrospective chart review was conducted that captured information including clinical staging, therapeutic modalities, pathologic findings, and patient follow-up. Factors affecting survival were assessed by nonparametric analysis and analysis of variance. RESULTS: There was no statistical significance for the effects of vascular invasion (P = 0.4019), lymphatic invasion (P = 0.3430), bone invasion (P = 0.1548), or positive margins (P = 0.1113) on survival. Extranodal extension and recurrent disease were strongly suggestive of influencing survival but were not statistically significant (P = 0.0650 and P = 0.0504, respectively). Nodal disease significantly affected survival (P = 0.0138) but did not affect recurrence (P = 0.451). CONCLUSION: Mean survival for this cohort was 30.6 months. Positive node status significantly affected mean overall survival in this series, whereas extracapsular disease did not. These data suggest that aggressive surgical management of neck disease is mandated to maximize survival.

Adult↗
PubMed2000

Risk factors associated with hypothyroidism after laryngectomy.

Hypothyroidism is a well-documented complication after treatment of head and neck cancer and is particularly significant among patients undergoing laryngectomy. The objective of this study was the identification of factors associated with the development of hypothyroidism in this population. Records of 136 patients treated with laryngectomy were retrospectively reviewed in an attempt to define a risk factor profile for patients in whom hypothyroidism is most likely to develop after laryngectomy. The Cox proportional hazards model was used to identify factors significantly related to an increased risk for development of hypothyroidism. The actuarial method was used to estimate the period of greatest risk for the development of hypothyroidism. Increased risks were found for patients who were female (P = 0.0049), received preoperative radiation therapy (P = 0.0022), had invasion of the thyroid gland by tumor (P = 0.0003), had presence of cervical metastases (P = 0.0022), and had postoperative fistula (P = 0.0095). From the actuarial method, we estimated that the period of time when patients were at greatest risk for development of hypothyroidism was between 0 and 14 months after surgical intervention. Wound complications were twice as frequent in hypothyroid patients. Perioperative awareness of risk factors associated with the development of hypothyroidism in patients undergoing laryngectomy allows for early recognition and management of hypothyroidism and may reduce the number of complications related to wound healing and fistula.

Aged↗
PubMed1999

Auricular carcinoma with temporal bone invasion: outcome analysis.

Invasion of the temporal bone by cutaneous carcinoma of the auricle and periauricular skin is an ominous prognostic sign. Management includes aggressive resection of cutaneous disease as well as resection of temporal bone to obtain a medial margin. Analysis of data from 21 patients with temporal bone invasion caused by cutaneous malignancy is presented. Overall survival is approximately 63%. Cumulative survival is significantly decreased in patients with squamous cell carcinoma when compared with other invasive malignancies. Univariate and covariate analyses demonstrate that nodal status, positive microscopic soft tissue margins, and persistent perineural disease at the skull base did not significantly affect survival in this series. There is a trend toward increased survival in patients receiving postoperative radiation in this series.

Adult↗
PubMed1999

Assessment of plate use for mandibular reconstruction: has changing technology made a difference?

Reconstruction of mandibular defects with a variety of alloplastic materials during a 22-year period was reviewed. Outcomes were examined to determine whether specific plating technology affected the incidence of plate-related complications including plate exposure, plate fracture, and plate removal. Repair with the miniplate, reconstruction plate, titanium hollow screw reconstruction plate, and locking reconstruction plate was evaluated. Although the incidence of plate fractures has decreased, there was no significant change in the rate of plate exposure. Recurrent disease was noted to be a significant contributing factor in the development of plate-related complications.

Adult↗
PubMed1998

Reconstruction after temporal bone resection.

Reconstruction of soft tissue defects after temporal bone resection can vary from simple closure of the external auditory canal to complex flap coverage of extensive defects. Between 1987 and 1996, 34 patients underwent lateral skull base resections and reconstruction for invasive carcinoma of the temporal bone. Seven underwent sleeve resection and/or radical mastoidectomy. Sleeve resection was managed with tympanoplasty, canalplasty, or obliteration of the external auditory canal (10). There were 24 lateral temporal bone resections and four subtotal temporal bone resections. Larger defects created by lateral and subtotal temporal bone resections required closure with a combination of temporalis flaps and local rotational cutaneous flaps (13). Lower island trapezius flaps (five), free flaps (four), and pectoralis major flaps (two) were also used. Indications and efficacy of each method are discussed, and treatment outcomes are presented.

Adult↗
PubMed1996

Effects of radiation therapy on reconstruction of mandibular defects with a titanium reconstruction plate.

Titanium fixation plates are commonly used in reconstruction of mandibular defects resulting from tumor resections in head and neck surgery. The effects of radiation therapy on the interface of bone, plate, and soft tissue were examined in this in vivo study. Four conditioned beagles had 1-cm segmental mandibular defects that were reconstructed with titanium plates. Two of the four also had placement of vascularized bone grafts. Healing was evaluated with or without postoperative radiotherapy. After collection of tissues using histologic methods and analysis with energy-dispersive spectroscopy, we found that the effects of radiation on bone-plate and bone-screw interfaces is minimal. Although radiation decreased the bone density and the rate of bone repair at the bone-screw interface, this did not appear to affect stability of the plate repair or the viability of bone tissue.

Animals↗
PubMed1995

Assessment of bone formation during osteoneogenesis: a canine model.

Distraction osteoneogenesis, callotasis, has been demonstrated to be an effective means of lengthening long bones. A variation of Ilizarov's technique produces a transport disk from one cut surface of bone within a defect and advances the disk to the opposite surface to close the defect. This process, previously described by Costantino et al. (Arch Otolaryngol Head Neck Surg 1990; 116:535-45), demonstrated bone formation within the distraction site. The precise mechanism of bone formation has not yet been described for the mandible. Four conditioned beagles were studied, with one control dog maintained in neutral fixation and three dogs distracted at 0.25 mm every 8 hours. A two-cm defect was closed, and dogs were kept in fixation for 1 week after closure, after which they were killed. Three sites were evaluated: (1) the distraction seam, (2) the interface of the cortical and distracted bone, and (3) the cortexes at the closed defect. Each site was bisected, and one half was decalcified for immunohistochemical and hematoxylin and eosin pathologic evaluation. The vascular basement membrane was labeled for laminin and type IV collagen. Both of these substances demonstrate the differentiation of the vascular matrix component predisposing primary bone formation. Labels were intense at the distraction seam where intense angiogenesis occurred. No hyalin cartilage was observed at the distraction site, which indicates that the fixation was stable and that ossification occurred primarily without intermediate callous formation. This model demonstrated that osteoclasts within the canine model produce bone through primary bone formation within an angiogenic matrix rich in basement membrane laminin and type IV collagen. Likewise, bone is species specific in mineral composition for dog mandible. Understanding the formation and composition of distracted bone is essential for understanding application of this technique within the clinical setting.

Animals↗
PubMed1994

Testing biomechanical strength of repairs for the mandibular angle fracture.

A biomechanical model using polystyrene mandibles with simple angle fractures was developed to evaluate the structural strength of a variety of commonly used plate repairs. The model standardized the fracture location, load site, plate location, and site of deformation measurement. The only variables in the study were the nine different reconstruction types tested. Precise measurements of the deformation under load demonstrated statistically significant intra-group reproducibility for each repair. Data support previous clinical and experimental studies demonstrating the superiority of a two-plate system applied to the tension and compression regions of the mandible when compared to single-plate repairs using either noncompression (bridging) or eccentric dynamic compression plates.

Biomechanical Phenomena↗
PubMed1994

Basement membrane of blood vessels during distraction osteogenesis.

A canine model of distraction osteogenesis has recently been developed that permitted the evaluation of bone formation and its vascularization during bifocal callotasis. In this model, the authors examined the composition of the blood vessels during distraction osteogenesis of the mandible for laminin and for Type IV collagen, both constituents of the vascular basement membrane. At the fibrous distraction site, at the juncture of the free cortical surface and the regenerated bone, and at the abutting cortical surfaces at the distal margin of the defect, laminin and Type IV collagen were present in all vessels.

Animals↗
PubMed1994

Evaluation of distraction osteogenesis by scanning electron microscopy.

A model of bifocal distraction osteogenesis in the canine model was used to assess and quantitate the mineral content of the newly forming bone within the canine mandible. A 2-cm defect was created in the body of the mandible, and after a posterior osteotomy, the transport disk was advanced at 0.25 mm per 8 hours for 21 days and then held in rigid fixation for an additional week. As a control for this study, three additional dogs underwent the same procedure with the exception that the transport disk was not advanced. Electron dispersive spectroscopy analysis was performed on the newly formed regenerate bone and compared with areas of existing cortical bone of both the transport disk and the mandible. In the control model, special note was made of the pericortical callus at the osteotomy site as well as of the regenerative bone that filled the 2-cm defect in the body of the mandible. Calcium/phosphorous ratios were used to assess the composition of the mineralized regions of the mandible. The regenerate bone that filled the defect and the mineralized callus surrounding the site of osteoclasis in the control mandible were significantly different in composition when compared with the regenerate bone that formed during distraction osteogenesis. This suggests that distraction osteogenesis may effect an initial matrix production that is more similar in composition to the mature cortical bone from which it was derived than does periosteal regeneration and filling of an osseous defect.

Animals↗
PubMed1993

Use of bone for obliteration of the nasofrontal duct with the osteoplastic flap: a cat model.

The management of the frontal sinus remains controversial for traumatic and inflammatory disease. The osteoplastic flap with fat obliteration has become the treatment standard, although late failures with infection and mucocele formation may arise. Theories for mucocele formation include regrowth of residual mucosa from the sinus and ingrowth of mucosa from a nonobliterated nasofrontal duct. A study to evaluate the means of nasofrontal duct obliteration was developed. Three cat groups were evaluated at 1, 2, and 3 months. Group 1 had the duct and sinus obliterated with fat. Group 2 had the duct obliterated with bone and the sinus with fat. Group 3 had only the duct obliterated with bone. There was no mucosal ingrowth in any of the sinuses for the intervals studied. In group 1, fat volume was seen to decrease over time with replacement by fibrous tissue within the duct. Groups 2 and 3 developed progressive obliteration of the duct with new bone formation. One may infer that fat obliteration alone does not provide a predictable stable situation as fat atrophies within the duct and may allow mucosal ingrowth. Bone obliteration was shown to be progressive within the duct from osteogenesis. This is the first experimental model to correlate clinical observations of the use of bone for sinus obliteration. This study concluded that bone obliterates the nasofrontal duct better than the accepted standard of fat, independent of the material used to obliterate the sinus.

Adipose Tissue↗
PubMed1991

Condylar neck fractures of the mandible.

Despite the effectiveness and many advantages of closed reduction of condylar neck fractures, open reduction techniques offer the advantage of anatomic repositioning of the fracture, which may reduce resultant deformities, malocclusion, and temporomandibular joint derangements in patients with complex subcondylar fractures. This objective is best achieved with rigid plate and screw fixation to obtain the stability required for immediate function. This article presents guidelines for the experienced surgeons who wish to address this controversial problem.

Aged↗
PubMed1990

Reconstruction of mandibular defects in irradiated patients.

In this prospective study, mandibular reconstruction using titanium plates was evaluated in 31 patients treated between July 1988 and January 1990. Sixteen patients had prior surgery; 13 had prior radiotherapy. In 11 patients, prior radiation and surgery had failed. Sixteen patients received postoperative radiotherapy either in standard or accelerated fractions. Twelve patients had complications of either intraoral (8), extraoral (5), or combined (1) plate exposure or fistula formation (2). Factors significantly related to complications were poor nutrition, accelerated radiation, and recurrence. Sixty-one percent of all patients healed uneventfully. When patients with complications secondary to recurrence who subsequently died were excluded, the success rate was 73%. Only one patient had an unacceptable result that produced a cosmetic and functional deformity despite secondary repair.

Adult↗