Posttreatment Hemorrhage Research Articles

Spetzler-Martin分類Grade IVの脳動静脈奇形に対する治療

We retrospectively analyzed treatment modalities and outcomes in 51 cases of cerebral arteriovenous malformation Grade IV (Spetzler- Martin's classification) admitted to our institute since 1986. Twenty-five out of 33 cases with hemorrhagic onset received surgical resection with or without preoperative embolization. Total resection was achieved in 21 cases, and small residual nidus was treated by postoperative radiosurgery in 2 out of 4 subtotally resected cases. Six out of 33 hemorrhagic cases received radiosurgery with or without preradiosurgical embolization. Twenty-six out of 33 hemorrhagic cases obtained complete disappearance of nidus. On the other hand, 4 out of 18 non-hemorrhagic cases received surgical total resection, 4 radiosurgery, 6 partial embolization, and 4 observation. Surgical morbidity was 7% and mortality was 0%, and post-treatment hemorrhage was seen in 8 cases (1 after subtotal resection, 2 after radiosurgery, 5 after partial embolization). Surgical resection can be achieved with acceptable morbidity, and complete obliteration of nidus should be accomplished in any treatment modality to avoid post-treatment hemorrhage.

Radiosurgery for cavernous malformations.

The authors examined 22 patients with cavernous malformations (CMs) who had undergone gamma knife radiosurgery (GKRS) to assess the value of this procedure in treating these lesions. At the Karolinska Hospital, GKRS was used to treat 23 patients with CMs during the period of 1985 through 1996. One of the patients was lost to follow up and the treatment results of the 22 remaining patients were analyzed. In the first half of the series, the CMs were treated with high doses of radiation (> 15-Gy dose to the periphery); in the second half of the series, lower doses were used. Nine of the 22 patients suffered a post-GKRS hemorrhage and six developed a radiation-induced complication (two of these patients experienced both). Some time after GKRS was performed, surgical removal of the CM had to be undertaken in four patients because of hemorrhage and in two patients because of radiation-induced complications. Four of the nine patients who experienced no post-GKRS hemorrhage or radiation-induced complication were treated before 1990; recent magnetic resonance imaging revealed a decrease in the size of the CM in three of these individuals and no size change in the other. The annual post-GKRS hemorrhage rate was 8% in this group. There was a trend in the hemorrhage rate to decrease 4 years postsurgery. There was also a trend for higher radiation doses administered to the periphery of the lesion to result in a lower risk of posttreatment hemorrhage. However, it could not be concluded whether GKRS affects the natural course of a CM. The incidence of radiation-induced complications was approximately seven times higher than that expected if the same number of patients had been treated by GKRS with the same radiation dose distributions for arteriovenous malformations instead of CMs. The high incidence of radiation-induced complications does not seem to justify the limited protection the treatment may afford in only exceptional cases. A prospective randomized study is needed before the role of radiosurgery in the management of these lesions can be defined. Until such a study has proved differently, a caveat must be raised for the treatment of CM with GKRS.

Gamma knife surgery for previously irradiated arteriovenous malformations.

The goal was to report the treatment results after a second gamma knife treatment and to compare them with the results obtained after a first gamma knife treatment, as well as to investigate whether the models to predict the results after a first treatment are also applicable after gamma knife treatment of previously irradiated arteriovenous malformations. The number of complications and the posttreatment hemorrhage rate were recorded for 112 patients in the study, and the number of obliterations was recorded for the 101 patients for whom conclusive angiograms were obtained. The results were compared with the expected results after a first gamma knife treatment. The observed number of obliterations was 62, which is not significantly different from the predicted number of 65. There were 14 observed and 5 predicted complications. When the risk from the preceding radiation treatment was added, the observed number of complications was similar to the predicted number. Six hemorrhages were observed after the second treatment. Of the 5 patients with unchanged arteriovenous malformation size after both the first and second treatments, 2 experienced hemorrhages after the second treatment, compared with none among the 81 patients for whom the malformation was obliterated or significantly decreased in size after the second treatment. The obliteration rate after gamma knife surgery for previously irradiated arteriovenous malformations is similar to that after primary gamma knife treatment. The complication rate increases with the amount of radiation previously given. The incidence of posttreatment hemorrhages is lower in the latency period if the malformation is affected by the radiation.

PROBABILITY OF OBLITERATION AND MANAGEMENT RISK FOLLOWING GAMMA KNIFE SURGERY FOR CEREBRAL AVM

In order to define the optimal treatment for an AVM patient, the probability of cure and the management risk following the treatment must be estimated before the treatment. Here, Gamma Knife surgery has an advantage over microsurgery and embolization with it's reproducibility within the variability of the individual radiation sensitivity. Based on more than 2000 treatments, we have developed models to predict the probability for obliteration, the risk for radioinduced complications and the probability for a post treatment hemorrhage within the first two years following a Gamma Knife treatment. The factors determining the overall outcome are the absorbed dose in the target and the brain, the AVM volume and location and the age and clinical history of the patient. The probability for obliteration equals 35, 69* ln (Dmin) -39, 66 and is AVM volume independent. The risk for radioinduced complications relates to the average dose in the 20cm3 tissue receiving the most radiation, and it is also related to the clinical history of the patient and the AVM location. Finally, the risk for post treatment hemorrhage increases with the age of the patient, and is higher for larger AVM. It decreases with increasing amount of radiation given, and it is independent of the clinical history of the patient. For retreatments, the model for prediction of obliteration is valid, but the risk for radioinduced complications is higher and the risk for post treatment hemorrhage lower as compared to following the first treatment.

The risk of hemorrhage after radiosurgery for arteriovenous malformations.

Two hundred and one patients with arteriovenous malformations (AVMs) treated radiosurgically between May 1988 and February 1995 are analyzed in this study. Twelve patients sustained a posttreatment hemorrhage during this period. Pretreatment factors associated with increased hemorrhage risk were identified in 11 of these patients and included arterial aneurysms, venous aneurysms, venous outflow obstruction, periventricular location, prior embolization, and prior surgical treatment. A detailed statistical analysis, using both Poisson regression and parametric survival regression techniques, was undertaken to determine whether radiosurgery had any effect on the risk of hemorrhage, when compared to the natural history of the disease, in those patients in whom a complete angiographic cure was not achieved. No evidence was found to support a statistically significant departure from the natural hemorrhage rate at any time period after radiosurgical treatment. Significant risk factors for hemorrhage appeared to correlate with increasing AVM volume.

Effect of Gamma Knife Surgery on the Risk of Rupture Prior to AVM Obliteration

The incidence for hemorrhage in non-obliterated arteriovenous malformations (AVM) during the first two years following Gamma Knife (GK) surgery was compared to the calculated incidence in untreated patients. There was a decrease in the incidence of hemorrhage as compared to the natural course. This difference was statistically significant. The actual number of hemorrhages during the first two years was 49 in a series of 1604 patients. Additionally, 41 hemorrhages occurred beyond the two years following treatment over the entire follow up time span of up to 24 years. For the first two years the calculated incidence was roughly two times higher than the observed incidence. This impact on the natural history was detectable already within six months after the treatment for the malformations totally covered with at least 25 Gy. The relation between a high minimum and a high average dose on the one hand and a lower risk for hemorrhage on the other hand was statistically significant. Low treatment doses and high age correlated to a higher risk. Neither hemorrhage prior to treatment nor time interval between presenting hemorrhage and treatment seemed to influence the risk for post treatment hemorrhage. The risk for permanent neurological deficit or death due to AVM rupture during the latency period between the time of treatment and total nidus obliteration was less than 0.5% for small AVM and 2-4% for large ones during the first two years. Of the 24 patients with sequelae following AVM rupture after treatment 14 died and 10 remained with neurological deficit of different degrees. However, all survivors were self sufficient.

Results of Neutron Radiosurgery for Inoperable Arteriovenous Malformations of the Brain

Twenty patients with inoperable arteriovenous malformations (AVMs) of the brain were treated with neutron radiosurgery. A 50 MeV cyclotron was used to deliver 9 Gy in a single fraction through 7 to 14 isocentric portals. The size and shape of the portals were customized to each treatment site. Nineteen patients have been followed for a median duration of 24 months following neutron radiosurgery. A radiographically demonstrable partial response was seen in 8 patients (42%). No complete responses were observed. There has been one post-treatment hemorrhage, no fatalities, and no evidence of radiation toxicity. The low response rate and absence of toxicity suggest that the appropriate dose for neutron radiosurgical treatment of AVMs is higher than the dose of 9 Gy at isocenter used in this initial study.

Pediatric brainstem glioma

Thirty-four pediatric patients, twenty with presumed and fourteen with biopsy or autopsy proven brainstem gliomas were imaged by CT and MR before radiation therapy. Twenty-eight patients received radiotherapy. Of these, eighteen fit the protocol for combined clinical and MR post-treatment evaluation. No cases of radionecrosis were seen at autopsy. This study shows that MR can demonstrate tumor response to radiation therapy, tumor progression prior to clinical deterioration, post-treatment cyst formation and hemorrhage. Although MR clinical correlation was not optimal on six week post-treatment evaluation, 4-10 month post-treatment MR scanning correlated well with clinical evaluation. MR appears useful in post-therapeutic monitoring of tumor response.

Analysis of Failures and Complications of Neodymium: YAG Laser Photocoagulation in Gastrointestinal Tract Tumors

Eight years of experience with endoscopic Nd:YAG laser photocoagulation were analyzed in retrospect in an attempt to identify factors relating to both failures and complications of laser therapy, and to delineate its limits and pitfalls in benign and malignant tumors. Three hundred and seventy-eight patients were studied, including 42 with gastroesophageal cancer, 180 with colorectal adenoma and 156 with colorectal malignancy. Patients with gastroesophageal cancer (n = 42) were referred mainly for obstruction in esophageal cancer and for bleeding in gastric cancer, with successful palliation in 86 and 81%. Hemorrhage was the only complication seen, twice during and twice after treatment. Pain, heat and smoke-induced complaints and sometimes temporary increased dysphagia were mentioned. Two white-surfaced tumors did not react at all. Patients with colorectal adenoma (n = 150) were divided into groups according to the size of the lesion. Definitive, histologically documented eradication of adenomatous tissue was achieved in 43% of the extensive, in 69% of the intermediate, and in 97% of the small adenomas. Major complications, mainly stenosis and hemorrhage, occurred in 6.4%, 7.6% and none of the lesions, respectively, and minor complications were seen in 57.4, 30.8 and 13.8%, respectively. Stenosis appeared to be related only to prior electrocoagulation and to excessive delivery of energy. Post-treatment hemorrhage occurred at about day 7. In familial polyposis (n = 30) surveillance of the rectal stump was successful in 84%, with major and minor complications in 4% and 12%. In colorectal cancers (n = 156) treated for palliation of bleeding and obstruction, success was obtained in 91%. major complications (13%) consisted mainly of stenosis and perforation.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser photocoagulation in the palliation of colorectal malignancies

Besides surgical intervention, there are virtually no palliative treatment modalities available for bleeding and/or obstructing colorectal malignancy. The usefulness and safety of laser photocoagulation was prospectively investigated in 63 patients with colorectal cancer. The merits were evaluated in the treatment of obstruction (16 patients), bleeding (32 patients), and combined hemorrhage and obstruction (15 patients). Luminal patency could be restored in 15 (94%), hemostasis was achieved in 28 (88%), and treatment was effective in 13 (87%) patients with bleeding and obstructing tumors. In the 56 evaluable and initially responding patients, no beneficial long-term results were achieved in six patients, as major complications of (re)stenosis, necessitating colostomy, occurred in three, posttreatment hemorrhage with need for blood transfusion in two, and a pararectal abscess formation was seen in one patient. Except probably for this pararectal abscess, there was no treatment-related death. Transient stenosis and laser-induced bleeding, as minor complications present in 12 (19%), responded favorably upon reinstitution of laser photocoagulation. The beneficial effect of laser photocoagulation was, in general, evident after 2 to 3 sessions. Forty-six patients could be discharged from the hospital and their treatment could be continued in the outpatient clinic. Further hospital admission could be avoided in 39. Laser treatment for palliation of obstructing and/or bleeding colorectal cancer proved to be an efficacious, safe, and rapidly effective therapy. Laser photocoagulation can be considered as a valuable alternative to aggressive surgical intervention in the absence of other conservative treatment modalities in palliation.

Nd:YAG laser photocoagulation in colorectal adenoma: Evaluation of its safety, usefulness, and efficacy

The usefulness, efficacy, safety, and tissue effects of Nd:YAG laser photocoagulation were investigated prospectively in 100 patients. Sixty-seven elderly patients with colorectal adenoma and 21 patients with rectal stump polyps after colectomy and ileorectal anastomosis in familial polyposis were evaluated. We subdivided our patients into those with extensive, intermediate, and small lesions, and we assessed completeness of tumor ablation, recurrence, and complications in all three groups. In the extensive group only 8 patients achieved complete (i.e., gross endoscopic and histologic) tumor ablation, whereas in 18 patients adenomatous tissue persisted or recurred after a tumor-free interval. In the intermediate group complete tumor ablation was achieved in 10 of 22 patients. Small adenomas were completely ablated in 18 of 19 patients. Five instances of carcinoma were detected in each subgroup of nonresponding extensive (18 patients) and intermediate (12 patients) lesions at follow-up. Prior to laser photocoagulation, symptoms such as watery diarrhea, excessive mucous discharge, hypokalemia, dehydration, and hematochezia and iron-deficiency anemia were present in 16 of 26 patients with extensive adenoma and in 13 of 22 patients with intermediate adenoma. Symptoms subsided during the course of treatment in all but 1 patient, even with the absence of complete ablation. Major complications, consisting of bleeding, symptomatic stenosis, or perforation occurred in 11.6% with extensive adenomas, in 9.1% with intermediate adenomas, and in none with small adenomas. Minor complications such as transient asymptomatic stenosis, minor posttreatment hemorrhage, pain, and “serositis” occurred in 30.9% with extensive lesions, in 27.3% with intermediate lesions, and in 10.6% with small lesions. There was no mortality. Treatment of multiple tiny polyps in 21 patients with familial polyposis was easy and efficient, without retraction and scarring, and without complications. We have concluded that laser photocoagulation is safe and uniformly effective in the ablation of small colorectal adenoma and in recurrent polyps in patients with familial polyposis. In patients with intermediate or large adenomas, symptoms are highly responsive to treatment, but complete tumor ablation—as documented upon repeated endoscopy and multiple biopsies—can only be expected in ~40%–50% in long-term follow-up. The high incidence of cancers in these two groups (21%) underscores the need for continued surveillance and frequent biopsy. Major and minor complications will occur in 40% in these sizeable lesions, being of clinical importance in only 10%. Nonsurgical management of such complications is usually successful and mortality is rare.