PubMed Health⌕ Search

Biomedical subjects

T Menovsky

Publications and source records attributed to T Menovsky.

At least 37 records · Page 2Linked to original sources
PubMed1998

Use of fibrin glue to protect tissue during CO2 laser surgery.

OBJECTIVE: Accidental injury of tissues during CO2 laser irradiation can lead to serious morbidity, especially during ear, nose, and throat, neurosurgical, and plastic-reconstructive procedures. This experimental study describes a new technique in which vital structures are coated with a thin layer of fibrin glue to protect them from accidental CO2 laser irradiation. STUDY DESIGN/MATERIALS AND METHODS: The femoral neurovascular bundles (femoral artery, vein, and nerve) of 12 rats were exposed. On one side the bundle was coated with fibrin glue, which is a biological two-component glue consisting of fibrinogen solution and thrombin. Upon application, an elastic mass on the neurovascular bundle was formed. The contralateral neurovascular bundle was left uncoated. Subsequently both bundles were subjected to CO2 laser irradiation at different powers (5, 7, and 9 W), with an irradiation time of 0.1 seconds. Light microscopy was performed at 30 minutes and 2 days after surgery. RESULTS: No macroscopic visible hemorrhages occurred during laser irradiation in the glue-coated bundle. Light microscopic evaluation revealed an undamaged neurovascular bundle without any signs of thermal damage. In the uncoated bundles intraoperative hemorrhages resulting from laser energy occurred in all specimens. Furthermore, severe thermal damage was present in arteries, veins, and nerves. CONCLUSIONS: Intraoperative coating with fibrin glue can serve as a shield to protect vital structures such as arteries, veins, and nerves from accidental CO2 laser exposure.

Animals↗
PubMed1998

Protective coating of cranial nerves with fibrin glue (Tissucol) during cranial base surgery: technical note.

OBJECTIVE: Cranial nerve deficit, either transient or permanent, is a common postoperative complication after cranial base surgery. Frequently, this occurs because intracranial nerves are directly involved in the cranial base lesion. However, any cranial nerve adjacent to the lesion can be damaged because of direct or indirect manipulation during surgery, leading to severe morbidity. We describe a new technique in which the adjacent intracranial nerves are protected from surgical trauma by coating the nerves with a biological two-component fibrin glue (Tissucol; Immuno A.G., Vienna, Austria). SURGICAL TECHNIQUE: The technique was performed in patients who underwent cranial base surgery for different types of lesions. After exposure of the operating field, the cranial nerves that were at risk of operative trauma were coated with a thin layer of fibrin glue using a double lumen catheter within a traditional suction device. RESULTS: With the application of fibrin glue, a protective layer of a rubbery consistency is formed around the nerve. No intraoperative complications or adverse effects of the application were noted. Moreover, no surgical injury of the nerves occurred and no or minimal postoperative cranial nerve deficit was noted in the coated nerves. CONCLUSION: Although it is difficult to compare the postoperative cranial nerve deficit in the coated nerves with a control group, we think that this technique is a valuable method to minimize or avoid intraoperative cranial nerve injury during cranial base surgery.

Cranial Nerve Injuries↗
PubMed1998

Intracranial repair of a divided trochlear nerve. Case report.

The authors report the case of a 37-year-old woman in whom the trochlear nerve was transected during removal of a meningioma in the cavernous sinus and subsequently repaired by using microsurgical techniques. This patient presented with a tumor in the posterior part of the right cavernous sinus with expansion over the tentorium. Preoperatively, she suffered from partial deficit of the right trochlear nerve. Intraoperatively, the trochlear nerve was noted to be completely encased by the tumor and was totally divided during removal of the lesion. After tumor resection, the trochlear nerve was repaired by using a sural nerve fascicle secured with sutures and fibrin glue. Six months after the operation, trochlear nerve regeneration became evident as the patient's binocular vision gradually improved. The patient regained normal functioning of the superior oblique muscle 3.5 years after surgery. It is concluded that repair of a divided trochlear nerve is worthwhile and can be followed by successful regeneration and an excellent functional recovery of the superior oblique muscle.

Adult↗
PubMed1998

Surgical management of ulnar nerve compression at the elbow: an analysis of the literature.

OBJECT: Surgical treatment for cubital ulnar nerve compression includes medial epicondylectomy, simple decompression, or anterior transposition (subcutaneous, intramuscular, or submuscular). There is a dearth of prospective randomized studies on which to base guidelines for choosing one operative treatment over another. The authors review the literature on this subject and present their findings. METHODS: The authors reviewed the literature from January 1970 to July 1997. Two authors decided independently whether an article should be included for review based on previously formulated inclusion and exclusion criteria. In addition to demographic information, data concerning preoperative status and outcome were extracted. For statistical analyses chi-square and Kruskal-Wallis tests were performed. Irrespective of their preoperative status, patients with simple decompression had the best outcome, whereas those with anterior subcutaneous and submuscular transposition had the worst. If outcome was related to the patient's preoperative status, a significant difference was not found among the various groups for those patients with a preoperative McGowan Grade 2. However, for those with McGowan Grade 3 (severe) symptoms, patients with anterior intramuscular transposition had the best outcome followed by those with simple decompression and anterior submuscular transposition. Statistical analysis was not possible for patients with McGowan Grade 1 because of the small numbers of patients in several treatment modality groups. CONCLUSIONS: Formulating a uniform guideline for operative treatment is not possible based on the results of this study. However, the authors believe that support is given to their policy, which is primarily to perform a simple decompression. Its surgical simplicity with preservation of the anatomy, especially the vascularization, and the possibility of rapid postoperative rehabilitation are also taken into consideration. If subluxation is found intraoperatively, anterior transposition is proposed.

Elbow↗
PubMed1998

Successful surgical repair of progressive exophthalmos caused by a meningocele in a patient with neurofibromatosis Type 1. Case report.

A case of surgical repair of progressive exophthalmos of the right eye in a 43-year-old woman with neurofibromatosis Type 1 (NF1) is presented. Preoperatively, the patient's ocular movements and visual fields were intact. Visual acuity was 20/30 on the right side and 20/20 on the left. Computerized tomography scanning demonstrated complete absence of the superolateral orbital wall on the right side with a large meningocele protruding into the right orbit. Intraoperatively, a new superolateral wall was constructed using the inner table of the left frontal bone as a bone transplant. A free galeoperiosteum flap was used for water-tight dural reconstruction. A few weeks postoperatively the patient's exophthalmos showed remarkable resolution. Her ocular movements, visual acuity, and visual fields remained unchanged. In conclusion, reconstruction of the superolateral wall and repair of a meningocele in a patient with NF1 is worthwhile and can be followed by excellent cosmetic results. More important, the patient's visual functions remain preserved.

Adult↗
PubMed1997

Effect of the CO2 milliwatt laser on tensile strength of microsutures.

BACKGROUND AND OBJECTIVE: Laser-assisted tissue repair is often accompanied by a high dehiscence rate, which may be due to alterations in suture material after laser exposure. The goal of this study was to investigate the effect of CO2 laser irradiation on the tensile strength of microsurgical suture material. STUDY DESIGN/MATERIALS AND METHODS: 10-0 nylon and 25 microns stainless steel threads were exposed to 12 combinations of power densities (62, 124, and 186 W/cm2) and pulse durations (0.5, 1, 2, 3 s) and tested on a tensometer for their tensile strength. RESULTS: At power densities of 186 W/cm2, the 10-0 nylon thread disrupted during laser irradiation, regardless of pulse duration. This was also the case at power densities of 124 C/cm2 for 2 s and 3 s pulse duration. At 124 W/cm2 for 0.5 and 1 s, the tensile strength decreased with 70% relative to the control. At 62 W/cm2, the tensile strength gradually decreased from 100% (0.5 s pulse duration) to 50% (3 s pulse duration) relative to control. Stainless steel thread resisted all laser irradiations. CONCLUSIONS: The 10-0 nylon thread is significantly compromised by irradiation with the CO2 milliwatt laser and therefore meticulous care should be taken not be irradiate the sutures during laser tissue welding.

In Vitro Techniques↗
PubMed1996

Laser tissue welding of dura mater and peripheral nerves: a scanning electron microscopy study.

BACKGROUND AND OBJECTIVE: In order to elucidate the mechanism of tissue welding, scanning electron microscopy (SEM) was used to investigate the ultrastructural changes on the surface of dura mater and peripheral nerves after CO2 laser welding. STUDY DESIGN/MATERIALS AND METHODS: The dura mater and the epineurium of the nerves was welded with a CO2 laser at 100 mW with pulses of 1.0 s (spot size 320 microns), both with and without additional use of a protein solder (egg white). The specimens were immediately examined using SEM. RESULTS: The laser tissue bonding mechanism is collagen-to-collagen attachment. After laser irradiation, the collagen fibrils are swollen, densely packed, and fused together. When a protein solder is used, the coagulated solder forms a solid bridge between the tissue edges, which is melted on and between the collagen fibrils. CONCLUSION: Laser welds in dura mater and peripheral nerves are the result of collagen-to-collagen bonding. In solder-assisted laser welds, the tissue connection is made by an internal and an external matrix of coagulated solder.

Animals↗
PubMed1996

Effect of CO2 milliwatt laser on peripheral nerves: Part I. A dose-response study.

In order to explore further the role of laser for microneural repair, the effect of CO2 laser irradiation on intact rat sciatic nerves was investigated. In total 40 rat sciatic nerves were exposed to 12 different combinations of laser power (50, 100, and 150 mW) and pulse duration (0.1 to 3 s) normally used for CO2 laser-assisted nerve repair. The results were evaluated 24 hr after surgery with functional toe-spreading test and light microscopy. Irradiations of 50 and 100 mW for up to 1 s exposure time per pulse resulted in almost no deficit in motor function, while 100 mW power with prolonged exposure times and 150 mW power resulted in a significant decrease in motor function. Light microscopy showed significant focal injury to the epi/perineurium and the subepineunal nerve fibres proportional to the laser energy applied to the nerve, consisting of Wallerian degeneration and thrombosis of blood vessels. In conclusion, a power of 50-100 mW in combination with a pulse duration of 0.1-1 s produced no or minimal thermal damage with no or a negligible loss of motor function. Therefore, combinations of power and pulse duration above these thresholds are considered less suitable for CO2 laser nerve repair.

Animals↗
PubMed1996

Interstitial laser thermotherapy in neurosurgery: a review.

One of the most recent laser treatment modalities in neurosurgery is interstitial laser thermotherapy (ILTT). In this review, experimental and clinical studies concerning intracranial ILTT are discussed. Two methods for intra-operative control of the laser induced lesions are described; i.e., computer-controlled power delivery, using a thermocouple that is positioned interstitially at the periphery of the tumour to maintain the desired temperature at that point, and MRI, to visualise the extent of the thermal lesions induced by ILTT. The results show that ILTT using a Nd: YAG laser is easy and relatively effective in the treatment of small deep-seated brain tumours with minimal risk and complications. This review is concluded with suggestions for further improvement of this treatment modality.

Animals↗
PubMed1995

Ultrasonography in acute interstitial laser irradiation of the pig brain: preliminary results.

In this preliminary study, the use of real-time ultrasonography to visualize the effects of acute interstitial Nd:YAG laser irradiation was investigated in the normal pig brain. In six pigs, a craniotomy was performed. In the frontal or temporal lobe, a thermal laser lesion was made using a 600-micron-diameter optical fiber at powers of 1 W, 2 W, and 4 W with exposure times of 5 min and 10 min. Ten to thirty minutes after laser irradiation, the pigs were sacrificed. Ultrasound imaging was performed before, during, and after laser irradiation. During laser irradiation, a clear hyperechogenic area was observed around the fiber tip. The onset of the changes and the extent of the lesion were dependent on the power and exposure time. Histologic examination showed thermal lesions consisting of coagulation necrosis and edema. The size of the lesions correlated well with size on ultrasound imaging. The maximal lesion dimension was 12 mm in diameter (4 W for 5 min). In conclusion, within the limitations of this experimental setup, it is feasible to visualize interstitial laser-induced lesions in the brain by ultrasonography. This method is safe and simple and may be helpful in future applications of interstitial thermotherapy in brain tissue.

Animals↗