Kalle Aitasalo

BIOACTIVE GLASS S53P4 IN FRONTAL SINUS OBLITERATION: A LONG-TERM CLINICAL EXPERIENCE

Synthetic, osteoconductive, and antimicrobial bioactive glass (BAG) has been used in many surgical applications.

Obliteration of the frontal sinus cavity with bioactive glass

Bioactive glass (BG) is a glass ceramic material. It has been used as surgical bone replacement material in ear and oral surgery, orthopedics, and dentistry.

A modified protocol for early treatment of osteomyelitis and osteoradionecrosis of the mandible

The treatment of osteoradionecrosis (ORN) and early chronic osteomyelitis (COM) of the mandible and maxilla is controversial. Hyperbaric oxygen (HBO) at two to three times the atmospheric pressure at sea level can result in tissue oxygen tension of almost 400 mmHg. Herewith HBO increases oxygen supply in hypoxic tissue, thus inducing fibroblastic proliferation and capillary formation.

Reconstruction of orbital wall defects with bioactive glass plates.

PURPOSE Synthetic bioactive glass (BAG) is used in many surgical applications. Special bioactive glasses do not favor microbial growth. This study evaluated the clinical outcome of bioactive glass plates in reconstructive orbital surgery. PATIENTS AND METHODS In a retrospective series of 49 patients, 35 orbital floors and 6 orbital medial and superior walls were reconstructed after fronto-orbital trauma, and 8 patients were treated with BAG plates after fronto-orbital tumor resection. These patients were evaluated in terms of reconstruction materials, complications, and functional outcomes. RESULTS During the 2-year follow-up, 3 of the 35 orbital floor trauma reconstructions were reoperated (9%) because of diplopia, and new reconstructions with BAG were performed. In all of the 8 patients with tumors and in 6 of the patients undergoing orbital wall reconstruction, the plates were in the correct position after reconstruction, and none had to be removed. One patient with a benign tumor and 7 of the 8 patients with malignant tumors survived to the 2-year follow-up. CONCLUSIONS Reconstructive surgery of the orbit is one of the most demanding challenges in head and neck surgery. In orbital defect reconstruction, a BAG plate seems to be a well-tolerated and reliable reconstruction material alternative; however, BAG plates are brittle and rigid, and cannot be molded and shaped by a surgeon. The use of a stainless steel template of equal shape and size to a BAG plate is recommended to ameliorate this deficiency.

Craniofacial bone reconstruction with bioactive fiber-reinforced composite implant

A novel, bioactive, fiber‐reinforced composite implant is a solution to address the shortcomings in craniofacial bone reconstruction. A longitudinal clinical investigation with a follow‐up time of 4 years was conducted.

Steroid hormone receptors in laryngeal carcinoma.

The larynx has long been shown to be a target organ for androgenic steroids in both women and men, and specific androgen receptors have been determined in normal laryngeal mucosa and in laryngeal carcinoma tissue. In this study, samples from 21 primary laryngeal carcinomas, from 4 recurrent laryngeal carcinomas and from 1 cervical metastasis of laryngeal carcinoma were obtained at the time of surgery to assay specific androgen, estrogen, and progesterone receptors. Specific androgen receptors were found in 8 samples (31%). The level of receptors varied from 1.7 femtomoles (fmol) per milligram to 7.3 fmol/mg cytosol protein. Detectable levels of specific estrogen receptors were found in 18 samples (69%) and progesterone receptors in 8 of the 15 samples studied (53%). There was no apparent correspondence with donors’ sex, since samples from both females and males contained all kinds of receptors. We know that antiestrogen inhibits the growth of squamous carcinoma cells lines positive for estrogen receptors in vitro and that this effect is reversible with the appropriate hormone. Thus, the relatively high percentage of estrogen and progesterone receptors found in laryngeal carcinoma tissue may open new aspects in the treatment of laryngeal carcinoma with antihormones.

Bioactive Glass S53P4 in Mastoid Obliteration Surgery for Chronic Otitis Media and Cerebrospinal Fluid Leakage

Objectives: We evaluated the results of cases of chronic otitis media treated with mastoid obliteration surgery using bioactive glass S53P4. Methods: Twenty-five patients with chronic otitis media and 1 patient with cerebrospinal fluid leakage without chronic infection were treated with bioactive glass S53P4. Twenty patients had had previous surgery because of chronic otitis media with or without cholesteatoma. A mastoid obliteration was performed with bioactive glass S53P4 granules and a musculoperiosteal flap with or without bone paté. In 2 patients with a bony dehiscence at the middle cranial fossa, a bioactive glass plate was used to support the protruding dura. In addition, in 3 patients, occlusion of a dural fistula was needed. The median follow-up period was 34.5 months (range, 1 to 182 months). Results: Excluding the 2 patients with only 1 month of follow-up at our department, 96% of the patients had a dry, safe ear or only intermittent otorrhea. In 92% of the patients, the objective of achieving a smaller or nonexistent cavity was achieved. Conclusions: Bioactive glass S53P4 is a noteworthy material in mastoid obliteration surgery.

In vivo model for frontal sinus and calvarial bone defect obliteration with bioactive glass S53P4 and hydroxyapatite

An in vivo model was developed to investigate the usability of a frontal sinus and a calvarial bone defect obliteration with bioactive glass S53P4 (BG) and hydroxyapatite (HA) granules. Roofs of 21 Elco rabbit frontal sinuses were drilled open from 4 separate holes using a standard method, and the sinuses, located in pairs, in frontal bone were filled with BG on one side and with HA on the other side. Two parallel posterior defects were covered with a pedicled periosteum flap, and 2 anterior defects with a free flap. The stability of materials, new bone, and connective tissue formation were observed with histomorphometry, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), and X-ray pictures at 1, 3, 6, and 12 months postoperatively. The results showed more rapid resorption of filling material (p = 0.019) and new bone formation (p = 0.0001) in the defects filled with BG than in the corresponding HA-filled defects studied by histomorphometry throughout the study. New bone formation and resorption of materials were faster in defects covered by a pedicled flap than by a free periosteum flap. The results were supported by SEM histomorphometric and radiologic analysis. Both bioactive materials studied were well tolerated in frontal sinuses and in calvarial bone defects. The experimental model showed the influence of early periosteum vascularization on accurate frontal sinus filling and the healing process in rabbit frontal sinuses.

Experimental Follow-up Model for Clinical Frontal Sinus Obliteration with Bioactive Glass (S53P4)

Bioactive glass S53P4 (BG) is an osteoconductive allograft material. Since 1990, BG has been used in the obliteration of frontal sinuses in more than 30 consecutive patients. The patients have been monitored regularly with clinical examinations, computer tomography (CT) scans, laboratory tests and, in a few cases, biopsies have also been obtained. The material has been well tolerated and no loss of volume of obliteration material has been seen in the obliterated sinuses. However, in repeated CT monitoring and with Region of Interest (ROI) analysis, a decrease in the density of the obliteration material inside the frontal sinuses has been seen. In the present study, the clinical conditions after an obliteration operation were simulated and the behaviour of the BG in the obliterated area was observed. The aim was to study whether it is possible indirectly to estimate the resorption of a massive amount of BG with ROI analysis for monitoring the clinical success of the treatment. Thus two sizes of granules (0.63-0.8 mm and 0.8-1.0 mm) in eight separate BG amounts, weight 25 g, were tested in simulated body fluid (SBF) in standard conditions. The dissolution of silicon (Si) and phosphate (P) was detected with direct plasma atom emission spectroscopy (DCP-AES) monthly up to 6 months. The BG amounts were scanned with CT and the slices analysed using the ROI technique at 1, 3 and 6 months. The cumulative loss of Si and P in SBF was significant during the study ( p <0.0001) it and was stronger with smaller than with larger granules ( p <0.0001). This was shown correspondingly by the decrease of Hounsfield units ( p <0.0001) in ROI analysis. The method seems reliably to reveal the resorption of BG for clinical purposes.

Microvascular Free Tissue Transfers after Preoperative Irradiation in Head and Neck Reconstructions

Surgical reconstruction of large head and neck tumors involves great problems. Preoperative irradiation increases the risk of postoperative complications. The use of microvascular free flaps has definitive advantages over conventional reconstruction techniques and permits immediate preoperative high-dose radiation therapy. Eighty-eight patients, 55 (62%) men and 33 (38%) women, with head and neck tumors underwent microvascular reconstruction at the Turku University Central Hospital in 1985-1995; 77 of them were irradiated before surgery. All irradiated patients underwent primary reconstruction. The preoperative radiation dose was 50-65 Gy. The free tissue transfer was successful in 77 (88%) of the 88 patients. The success rate was 87% in irradiated patients and 91% in nonirradiated patients. Free tissue transfers are suitable for one-stage reconstruction in selected patients such as those receiving high-dose preoperative irradiation. The transfer of microvascular free flaps to the head and neck has become the most common reconstruction method owing to its increasing success rates as well as its excellent esthetic and functional results.