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Biomedical subjects

Michael Peleg

Publications and source records attributed to Michael Peleg.

11 recordsLinked to original sources

Maxillary sinus and ridge augmentations using a surface-derived autogenous bone graft.

PURPOSE: The purpose of this article is to describe a new technique and the anatomic sites for cutting and harvesting bone for grafting applications. A handheld instrument is described that cuts and collects thin shavings of bone from cortical surfaces. MATERIALS AND METHODS: This study included 193 consecutive patients who needed bone augmentation and simultaneous implant placement in the severely atrophic posterior maxilla and in the anterior maxilla with acquired defect of alveolar bone as a result of local trauma. A total of 477 implants were placed. Clinical criteria for evaluation at time of implant exposure included stability in all directions, crestal bone resorption, and any reported pain of discomfort. RESULTS: There were no failures of the anterior maxilla group, and no signs of bone resorption were noted at the second stage surgery or during the follow-up. During initial and late healing, there was no dehiscence of the soft tissue flaps and no membranes were exposed. Core biopsies typically showed immature, newly formed bone and, on average, 27% to 36% vital bone. CONCLUSION: From this research, it appears that excellent implant success rates can be achieved in grafted sinuses or ridges when a locally harvested autogenous bone graft with a ribbon geometry is used.

Alveolar Process↗

Primary diffuse large cell lymphoma of the mandible.

Primary diffuse large cell lymphoma of the mandible is a rare form of extranodal non-Hodgkin's lymphoma (NHL). Herein we present 4 cases treated at our institution over a 5-year period and review 40 cases previously reported in the English-literature. The median age at presentation is 51 years with equal distribution between males and females. At presentation the lymphoma is usually limited to the jaw (stage IE) and the most common presenting symptoms include swelling of the jaw (58%), pain (53%), and mental dysesthesia or numbness (20%). Despite symptoms of numb chin syndrome, central nervous system (CNS) involvement at presentation has not been reported. The reported therapy of this rare diffuse large cell lymphoma presentation is very heterogeneous, however majority of patients were treated with combination of chemotherapy and radiotherapy with estimated 5-year overall survival of only 60%. Multi-center prospective clinical trials are needed to determine the optimal therapeutic approach to this rare diffuse large cell lymphoma presentation.

Adult↗

Platelet-rich plasma for bone graft enhancement in sinus floor augmentation with simultaneous implant placement: patient series study.

The use of autologous platelet-rich plasma (PRP) as a source for growth factors in bone grafting is a relatively new and promising technique. Early controlled studies indicate that combining PRP with autologous bone grafts significantly enhances the rate of bone formation and maturation. The study consisted of 105 patients who required sinus augmentation with crestal bone height of less than 5 mm in the posterior maxilla. All patients received a composite bone graft that consisted of 30% to 40% autogenous bone harvested from the lateral wall of the maxilla zygomatic-maxillary buttress and the tuberosity and 60% to 70% xenograft. A total of 50 mL of blood was obtained from each patient before the surgical treatment for preparation of 10 mL of PRP. The graft-PRP mixture was activated by human thrombin. All sinus augmentations were carried out simultaneously with dental implants. At 6 months postoperatively, implants were exposed showing no clinical evidence of crestal bone loss around the implants both clinically and radiographically. All implants were clinically osseointegrated and loaded with fixed porcelain fused to metal prosthesis. The use of PRP in augmenting the severely atrophic posterior maxilla has obvious clinical benefits in terms of reducing the healing period of bone maturation, better graft handling, and accelerated soft tissue healing.

Adult↗

Amputation neuromas after neck dissection.

OBJECTIVE: We sought to define the incidence of neuroma formation after neck dissection in a large series of patients. METHODS: One hundred fifty-three patients who were seen during a 2-year period (followed for 3 months to 10 years; mean, 52 months) were evaluated for neuroma formation after neck dissection (185 procedures). Cut nerve edges were not routinely ligated or cauterized. RESULTS: Operative records indicated that except for 4 cases, the stumps of the great auricular nerve and cervical branches were left intact after resection. No cases of palpable neuromas were found. In one case of a revised neck, a small macroscopically indiscernible nodule was histologically defined as neuroma. CONCLUSION: No neuromas were discovered in our series of neck dissection cases. If found, it is imperative these lesions be differentiated from recurrent cancer. Our results do not support any interference with cut nerve edges.

Adult↗

Pulmonary function after pectoralis major myocutaneous flap harvest.

OBJECTIVE: The pectoralis major myocutaneous flap is widely used in the reconstruction of surgical defects in the head and neck region. Pulmonary atelectasis has been reported in patients undergoing these procedures, and many of these patients are heavy smokers and drinkers and have associated cardiopulmonary disorders. Flap harvest and donor site closure may lead to impairment of pulmonary function before and after the use of pectoralis major myocutaneous (PMC) in surgical reconstruction in patients with cancer of the head and neck. METHODS: Patients undergoing extirpation of head and neck tumors with PMC reconstruction were prospectively evaluated. Patient age, smoking history (pack-years), anesthesia duration, percentage predicted pre- and postoperative FEV1, percentage-predicted pre- and postoperative FVC (forced vital capacity), and preoperative SaO2 (oxygen saturation) were evaluated. Preoperative FEV1/FVC ratio was calculated. Chest x-rays were reviewed. RESULTS: Only 11 patients, 5 of whom smoked, could be evaluated postoperatively. Preoperative FEV1/FVC was more than 70 and FEV1 more than 75% predicted in all patients. A decrease in FVC was observed in 7 of the 11 patients, which ranged between 2% and 27% without any clinically obvious respiratory manifestations. A baseline SaO2 of more than 96% was noted in all patients. Four of 9 postoperative chest x-rays demonstrated atelectasis. CONCLUSIONS: PMC harvest and donor site closure may lead to the recorded decrease in FVC measurements. These changes did not manifest clinically. Nevertheless, alternative methods of surgical defect closure should be considered in patients with severe preexisting pulmonary disorders.

Aged↗

Syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion in patients following neck dissection.

OBJECTIVES/HYPOTHESIS: The syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion (SIADH) is a disorder in which release of antidiuretic hormone is independent of plasma osmolarity, resulting in fluid retention and development of dilutional hyponatremia. The incidence of SIADH following neck dissection was found to be 18% to 30% in two separate reports. The incidence of SIADH in a cohort of patients who underwent neck dissection was prospectively studied. METHODS: Eighty-six patients were included in the study, along with a control group of 19 patients who underwent other neck procedures. Patient gender, age, physical condition (American Society of Anesthesiologists score), type of neck dissection, prior treatment, and smoking history were noted. Blood and urine osmolarity and sodium levels were sampled before surgery and during the first 24 hours after the surgery. These were recorded daily in cases with SIADH until the syndrome resolved. RESULTS: The incidence of SIADH was only 1.15% in patients before surgery. The syndrome developed in seven patients following neck dissection (8.14%) and in none of the patients in the control group. SIADH resolved within 72 hours at the latest. No association was found with patient gender, age, physical condition, or type or laterality of neck dissection. A statistically significant connection between the syndrome and history of smoking was noted (P <.05), and it was more commonly seen in patients with node-positive necks (P =.1231). CONCLUSIONS: SIADH following neck dissection may be less common than formerly reported. Previous studies have presented contradicting data concerning the influence of tumor recurrence or prior radiation therapy on its incidence. Our results indicate no such association. A statistically significant connection between smoking and the syndrome was found. No clinical symptoms developed in the patients with SIADH, but it seems prudent to suggest limiting fluid intake in the first postoperative 24 hours for patients following neck dissection.

Adolescent↗

Lateralization of the inferior alveolar nerve with simultaneous implant placement: a modified technique.

PURPOSE: Several nerve repositioning techniques have ben presented in the literature, each with limitations. This article presents a new technique involving the use of 2 osteotomies, with minimizes particularly the potential duration of sensory disruption and the risk of nerve paresthesia and inadvertent nerve transection or compression. MATERIALS AND METHODS: Ten patients ranging in age from 47 to 67 years were selected for nerve lateralization utilizing the modified technique. A total of 23 cylindrical implants were placed. An average follow-up period was 29.8 months. RESULTS: Of the 10 patients, 4 experienced total return of sensation within 3 to 4 weeks. One patient experienced complete recovery at 6 weeks. DISCUSSION: Creating 2 osteotomies as described minimizes the chances for postoperative neuropraxia and nerve paresthesia or anesthesia. CONCLUSION: When there is moderate-to-severe bone resorption of the mandible posterior to the mental foramen, repositioning the inferior alveolar nerve using both an anterior and posterior osteotomy allows for more bone to accommodate ideal placement and greater length of implant.

Aged↗

Predictability of simultaneous implant placement in the severely atrophic posterior maxilla: A 9-year longitudinal experience study of 2132 implants placed into 731 human sinus grafts.

PURPOSE: One-stage implant placement in the grafted maxillary sinus has traditionally been limited to patients with at least 5 mm of residual bone to ensure complete implant stabilization. The aim of this prospective study was to determine the long-term survival rates of implants with roughened surfaces placed immediately into maxillary sinus grafts in patients with 1 to 5 mm of residual bone. MATERIALS AND METHODS: A total of 2132 microtextured screw-type (n=1374) or hydroxyapatite-coated cylinder-type (n=758) implants were immediately placed into the grafted sinuses of 731 patients. The implants were restored and monitored for up to 9 years of clinical follow-up. RESULTS: Cumulative survival at 9 years was 97.9% (n=2091 implants); 20.4% of the implants were placed in 1 to 2 mm of residual bone. DISCUSSION: Initial implant stability and parallelism were achieved through a combination of meticulous condensation of the particulate bone graft material around the implants, the frictional interface of the roughened implant surfaces and the host tissues, and selection of an appropriate graft material. CONCLUSIONS: Simultaneous implant placement into sinus floor grafts can be a predictable treatment option for patients with at least 1 to 2 mm of vertical residual bone height when careful case planning and meticulous surgical techniques are used.

Adult↗

Healing in smokers versus nonsmokers: survival rates for sinus floor augmentation with simultaneous implant placement.

PURPOSE: Evidence suggests that smoking is detrimental to the survival of dental implants placed in grafted maxillary sinuses. Studies have shown that improving bone quantity and quality, using rough-surfaced implants, and practicing good oral hygiene may improve outcomes. In this prospective study, the long-term survival rates of implants placed simultaneously with sinus grafting in smokers and nonsmokers were compared. MATERIALS AND METHODS: Implants with roughened surfaces were immediately placed into maxillary sinus grafts in patients with 1 to 7 mm of residual bone. A total of 2132 simultaneous implants were placed into the grafted sinuses of 226 smokers (627 implants) and 505 nonsmokers (1505 implants). A majority of the patients received a composite graft consisting of 50% autogenous bone. In both smokers and nonsmokers, approximately two thirds of the implants had microtextured surfaces; the remainder had hydroxyapatite-coated surfaces. The implants were restored and monitored during clinical follow-up for up to 9 years. RESULTS: Cumulative survival of implants at 9 years was 97.9%. There were no statistically significant differences in implant failure rates between smokers and nonsmokers. DISCUSSION: Implant survival was believed to depend on the following aspects of the technique used: creation of a large buccal window to allow access to a large recipient site; use of composite grafts consisting of at least 50% autogenous bone; meticulous bone condensation; placement of long implants (i.e., 15 mm); use of implants with hydroxyapatite-coated or microtextured surfaces; use of a membrane to cover the graft and implants; antibiotic use and strict oral hygiene; use of interim implants and restricted use of dentures; and adherence to a smoking cessation protocol.

Animals↗