Fusion rate: a time-to-event phenomenon

2004 ◽  
Vol 1 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Sagun K. Tuli ◽  
Jayshree Tuli ◽  
Peng Chen ◽  
Eric J. Woodard
Keyword(s):  
Median Time ◽  
Fusion Rate ◽  
Smoking History ◽  
Time To Event ◽  
Female Ratio ◽  
Content Type ◽  
Kaplan Meier ◽  
Significant Difference ◽  
Fine Print

Object. The term “fusion rate” is generally denoted in the literature as the percentage of patients with successful fusion over a specific range of follow up. Because the time to fusion is a time-to-event phenomenon a more accurate method of representation may be made using the Kaplan—Meier method of estimation. Methods. The current study was performed to illustrate that fusion rate is more accurately represented by median times as calculated using survival analysis. Patients undergoing a cervical decompressive corpectomy and reconstruction formed the basis of the primary analysis. A secondary analysis was made to evaluate the difference in the fusion times for one- compared with multilevel corpectomy cases. Data were collected at a tertiary care institution over a 5-year period with 6-month follow up after the last recruitment. Descriptive statistics of baseline patient characteristics, the extent of disease, and the surgical intervention were obtained. Fusion was the final outcome, and it was defined as the “event.” The presence of any trabeculae bridging between the vertebral body and allograft signified the occurrence of an event. Postoperative static radiographs were evaluated by independent neuroradiologists to assess the presence of fusion. Fusion rate was determined using the Kaplan—Meier estimate. The median time to fusion was calculated, as were the 95% confidence intervals (CIs). These were stratified for patients who underwent one- and two-level vertebrectomy. The log-rank test was used to differentiate between one-level and multilevel corpectomy. Multivariate analysis was performed using Cox regression for further evaluation, by adjusting for covariates (age, sex, smoking history). Fifty-seven patients underwent single- or multilevel corpectomy and fusion. The male/female ratio was similar, with a median age of 53 years. Fourteen patients had a history of cigarette smoking. Thirty-six patients underwent a one-level corpectomy, 20 a two-level corpectomy, and one patient underwent a three-level corpectomy. The analysis was restricted to one- and two-level cases. The median time to fusion for the cephalad and caudad aspect of the graft—host interface was 88 days (95% CI 82–94 days) and 85 days (95% CI 77–93 days), respectively. As generally reported in the literature, this translates to a 92% (by 2.1 years) and 93% (by 1.5 years) fusion rate, for the cephalad and caudad, respectively. The median time to fusion for the cephalad aspect of the graft for one-level vertebrectomy was 87 days (95% CI 83–91 days), whereas for two-level vertebrectomy was 90 days (95% CI 59–121 days). The median time to fusion for the caudal aspect of the graft—host interface was 85 days (95% CI 80–90 days) for one-level corpectomy and 90 days (95% CI 83–97 days) for the two-level cases. There was no statistically significant difference in the median time to fusion for one- and two-level corpectomy at either the superior or inferior aspect of the graft (p = 0.19 and 0.84, respectively). This held true even after adjusting for covariates. Conclusions. Fusion rate is a time-to-event phenomenon and is more accurately represented using the Kaplan—Meier method of estimation.

Incidence and clinical features of asymptomatic meningiomas

2000 ◽  
Vol 92 (5) ◽  
pp. 766-770 ◽  
Author(s):  
Jun-ichi Kuratsu ◽  
Masato Kochi ◽  
Yukitaka Ushio
Keyword(s):  
Clinical Features ◽  
Tumor Size ◽  
Morbidity Rate ◽  
Intracranial Tumors ◽  
Period Range ◽  
Female Ratio ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print

Object. The increased use of computerized tomography (CT) and magnetic resonance (MR) technology has led to an increase in the detection of asymptomatic meningiomas, although the surgical indication for these tumors remains undetermined. The authors investigated the incidence of asymptomatic meningiomas and their clinical features.Methods. An epidemiological survey was conducted of primary intracranial tumors diagnosed in Kumamoto Prefecture between 1989 and 1996. Follow-up neuroradiological imaging and clinical studies for asymptomatic meningiomas were performed.Primary intracranial tumors were diagnosed in 1563 residents. Of these lesions, 504 (32.2%) were meningiomas, and of these meningiomas 196 (38.9%) were asymptomatic. The incidence of asymptomatic meningiomas was significantly higher in individuals older than 70 years of age. Furthermore, the incidence of asymptomatic meningiomas was significantly higher in female than in male patients. Of the asymptomatic meningiomas in 196 patients, 87 (44.4%) were surgically removed, whereas 109 (55.6%) were treated conservatively. Of these conservatively treated patients, 63 received follow-up care for more than 1 year. In 20 of these 63 cases, the tumors increased in size over the 27.8-month average follow-up period (range 12–87 months), whereas in the other 43 cases, the tumor size did not increase during a 36.6-month average follow-up period (range 12–96 months). There was no significant difference with respect to age, tumor size, and male/female ratio between the patient group in which the tumor size increased and the group in which it did not increase during the follow-up period. Asymptomatic meningiomas that evidenced calcification on CT scans and/or hypointensity on T2-weighted MR images appear to have a slower growth rate.Conclusions. Among patients older than age 70 years who underwent operation for asymptomatic meningioma, the neurological morbidity rate was 23.3%; it was 3.5% among younger patients. This indicates that the advisability of surgery in elderly patients with asymptomatic meningiomas must be considered very carefully.

Effect of direct arterial bypass on the prevention of future stroke in patients with the hemorrhagic variety of moyamoya disease

2000 ◽  
Vol 93 (3) ◽  
pp. 397-401 ◽  
Author(s):  
Shoichiro Kawaguchi ◽  
Shuzo Okuno ◽  
Toshisuke Sakaki
Keyword(s):  
Moyamoya Disease ◽  
Superficial Temporal Artery ◽  
Temporal Artery ◽  
Ischemic Event ◽  
Content Type ◽  
Kaplan Meier ◽  
Significant Difference ◽  
Direct Bypass ◽  
Fine Print

Object. The authors evaluated the effects of superficial temporal artery—middle cerebral artery (STA—MCA) bypass in the prevention of future stroke, including rebleeding or an ischemic event, in patients suffering from hemorrhagic moyamoya disease by comparing this method with indirect bypass and conservative treatment.Methods. Twenty-two patients who had hemorrhagic moyamoya disease but no aneurysm comprised the study group. These patients' clinical charts were examined with respect to their treatment and clinical course after an initial hemorrhagic episode. The mean age of the patients was 43 years and the follow-up period ranged from 0.8 to 15.1 years, with a mean of 8 years. Eleven patients (50%) were conservatively treated. Among the 11 patients who were surgically treated, STA—MCA bypass was performed in six patients (27%) and encephaloduroarteriosynangiosis (EDAS) in the other five patients (23%). Nine patients (41%) presented with an ischemic or rebleeding event during the follow-up period. The incidence of future stroke events in patients who had undergone an STA—MCA bypass was significantly lower (p < 0.05) than that in patients who had been treated conservatively or with EDAS. Kaplan—Meier plots comparing stroke-free times in patients treated with direct bypass and those in patients who conservatively or with indirect bypass showed a significant difference (p < 0.05) in favor of direct bypass.Conclusions. The effect of STA—MCA bypass on the prevention of recurrent hemorrhage or an ischemic event in patients with hemorrhagic moyamoya disease has been statistically confirmed in this study.

Medulloblastoma: freedom from relapse longer than 8 years — a therapeutic cure?

1991 ◽  
Vol 75 (4) ◽  
pp. 575-582 ◽  
Author(s):  
Mark G. Belza ◽  
Sarah S. Donaldson ◽  
Gary K. Steinberg ◽  
Richard S. Cox ◽  
Philip H. Cogen
Keyword(s):  
Medical Center ◽  
Survival Rates ◽  
Adjunctive Treatment ◽  
High Dose ◽  
Content Type ◽  
Significant Difference ◽  
Long Term Follow Up ◽  
Fine Print

✓ Seventy-seven patients presenting with medulloblastoma between 1958 and 1986 were treated at Stanford University Medical Center and studied retrospectively. Multimodality therapy utilized surgical extirpation followed by megavoltage irradiation. In 15 cases chemotherapy was used as adjunctive treatment. The 10- and 15-year actuarial survival rates were both 41% with an 18-year maximum follow-up period (median 4.75 years). There were no treatment failures after 8 years of tumor-free survival. Gross total removal of tumor was achieved in 22 patients (32%); the surgical mortality rate was 3.9%. No significant difference was noted in the incidence of metastatic disease between shunted and nonshunted patients. The classical form of medulloblastoma was present in 67% of cases while the desmoplastic subtype was found in 16%. Survival rates were best for patients presenting after 1970, for those with desmoplastic tumors, and for patients receiving high-dose irradiation (≥ 5000 cGy) to the posterior fossa. Although early data on freedom from relapse suggested a possible beneficial effect from chemotherapy, long-term follow-up results showed no advantage from this modality of treatment. The patterns of relapse and survival were examined; 64% of relapses occurred within the central nervous system, and Collins' rule was applicable in 83% of cases beyond the period of risk. Although patients treated for recurrent disease could be palliated, none were long-term survivors. The study data indicate that freedom from relapse beyond 8 years from diagnosis can be considered as a cure in this disease. Long-term follow-up monitoring is essential to determine efficacy of treatment and to assess survival patterns accurately.

Results of degenerative spondylolisthesis treated with posterior decompression alone via a new surgical approach

2001 ◽  
Vol 95 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Tomoaki Kinoshita ◽  
Isao Ohki ◽  
Kenneth R. Roth ◽  
Kageharu Amano ◽  
Hideshige Moriya
Keyword(s):  
Japanese Orthopaedic Association ◽  
Degenerative Spondylolisthesis ◽  
Spinal Instability ◽  
Content Type ◽  
Significant Difference ◽  
Potential Alternative ◽  
The Mean ◽  
New Surgical Technique ◽  
Fine Print

Object. The purpose of this study was to assess radiologically demonstrated results and clinical outcomes in patients with degenerative spondylolisthesis who underwent posterior decompressive surgery via a new (unilateral) approach. This approach allows surgeons to perform central and bilateral decompression while only stripping the muscles unilaterally, thus preserving the posterior osteoligamentous complexes. Methods. The authors evaluated 51 consecutive patients in whom surgery was performed between 1987 and 1996. The mean follow-up period was 4.7 years. There was no statistically significant difference between the pre- and postoperative measurements in percentage of vertebral slippage. Postoperative dynamic angulation statistically decreased compared with its preoperative value (p < 0.05). Improvement of an average of 67% was shown on the Japanese Orthopaedic Association scale, and in 78% of these patients, good to excellent results were demonstrated. Secondary fusion was required in only three patients (5.9%). Conclusions. This new surgical technique offers a potential alternative for the treatment of degenerative spondylolisthesis in a minimally invasive manner, avoiding the risk of causing or aggravating postoperative spinal instability.

Long-term follow-up review of patients who underwent laminectomy for lumbar stenosis: a prospective study

1998 ◽  
Vol 89 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Manucher J. Javid ◽  
Eldad J. Hadar
Keyword(s):  
Success Rate ◽  
Herniated Disc ◽  
Lumbar Stenosis ◽  
Content Type ◽  
Lateral Recess ◽  
Lateral Recess Stenosis ◽  
Significant Difference ◽  
Fine Print

Object. Decompressive laminectomy for stenosis is the most common operation performed in the lumbar spine in older patients. This prospective study was designed to evaluate long-term results in patients with symptomatic lumbar stenosis. Methods. Between January 1984 and January 1995, 170 patients underwent surgery for lumbar stenosis (86 patients), lumbar stenosis and herniated disc (61 patients), or lateral recess stenosis (23 patients). The male/female ratio for each group was 43:43, 39:22, and 14:9, respectively. The average age for all groups was 61.4 years. For patients with lumbar stenosis, the success rate was 88.1% at 6 weeks and 86.7% at 6 months. For patients with lumbar stenosis and herniated disc, the success rate was 80% at 6 weeks and 77.6% at 6 months, with no statistically significant difference between the two groups. For patients with lateral recess stenosis, the success rate was 58.7% at 6 weeks and 63.6% at 6 months; however, the sample was not large enough to be statistically significant. One year after surgery a questionnaire was sent to all patients; 163 (95.9%) responded. The success rate in patients with stenosis had declined to 69.6%, which was significant (p = 0.012); the rate for patients with stenosis and herniated disc was 77.2%; and that for lateral recess stenosis was 65.2%. Another follow-up questionnaire was sent to patients 1 to 11 years after surgery (average 5.1 years); 146 patients (85.9%) responded, 10 (5.9%) were deceased, and 14 (8.2%) were lost to follow-up review. At 1 to 11 years the success rate was 70.8% for patients with stenosis, 66.6% for those with stenosis and herniated disc, and 63.6% for those with lateral recess stenosis. Eleven patients who underwent reoperation were included in the group of patients whose surgeries proved unsuccessful, regardless of their ultimate outcome. There was no statistically significant difference in outcome between 1 year and 1 to 11 years with respect to stenosis, stenosis with herniated disc, and lateral recess stenosis. Conclusions. In conclusion, long-term improvement after laminectomy was maintained in two-thirds of these patients.

Clinical course of patients with ossification of the posterior longitudinal ligament: a minimum 10-year cohort study

2004 ◽  
Vol 100 (3) ◽  
pp. 245-248 ◽  
Author(s):  
Shunji Matsunaga ◽  
Takashi Sakou ◽  
Eiji Taketomi ◽  
Setsuro Komiya
Keyword(s):  
Cohort Study ◽  
Clinical Course ◽  
Japanese Orthopaedic Association ◽  
Posterior Longitudinal Ligament ◽  
Cervical Canal ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print

Object. Ossification of the posterior longitudinal ligament (OPLL) may produce quadriplegia. The course of future neurological deterioration in patients with radiographic evidence of OPLL, however, is not known. The authors conducted a long-term follow-up cohort study of more than 10 years to clarify the clinical course of this disease progression. Methods. A total of 450 patients, including 304 managed conservatively and 146 treated by surgery, were enrolled in the study. All patients underwent neurological and radiographical follow-up examinations for a mean of 17.6 years. Myelopathy was graded using Nurick classification and the Japanese Orthopaedic Association scale. Fifty-five (17%) of 323 patients without myelopathy evident at the first examination developed myelopathy during the follow-up period. Risk factors associated with the evolution of myelopathy included greater than 60% OPLL-induced stenotic compromise of the cervical canal, and increased range of motion of the cervical spine. Using Kaplan—Meier analysis, the myelopathy-free rate in patients without first-visit myelopathy was 71% after 30 years. A significant difference in final functional outcome was not observed between nonsurgical and surgical cases in which preoperative Nurick grades were 1 or 2. In patients with Nurick Grade 3 or 4 myelopathy, however, only 12% who underwent surgery eventually became wheelchair bound or bedridden compared with 89% of those managed conservatively. Surgery proved ineffective in the management of patients with Grade 5 disease. Conclusions. Results of this long-term cohort study elucidated the clinical course of OPLL following conservative or surgical management. Surgery proved effective for the management of patients with Nurick Grades 3 and 4 myelopathy.

Early decompression and neurological outcome in acute cervical spinal cord injuries

1982 ◽  
Vol 56 (5) ◽  
pp. 699-705 ◽  
Author(s):  
Franklin C. Wagner ◽  
Bahram Chehrazi
Keyword(s):  
Spinal Cord ◽  
Neurological Outcome ◽  
Cervical Spinal Cord ◽  
Cord Compression ◽  
Content Type ◽  
Percent Recovery ◽  
Significant Difference ◽  
Admission Status ◽  
Fine Print

✓ To evaluate the effect on neurological outcome of spinal cord compression persisting after a closed injury, the authors reviewed 44 of 62 consecutively managed cases of cervical spinal cord and spine injuries at C3–7, inclusive. Decompression within 48 hours of injury was confirmed by myelography or open reduction. Neurological status, graded numerically on a spinal trauma scale at admission and at follow-up review (an average of 1 year ± 2 months after admission), and percent recovery of neurological deficit were compared to canal narrowing (22 severe, ≥ 30%; versus 22 moderate, 11% to 29%; or mild, ≤ 10%) and to delay before treatment (30 within 8 hours of injury versus 14 treated 9 to 48 hours after injury). Severe narrowing was equated with compression. Status at admission and at follow-up review was positively correlated. Patients with admission scores of less than 2 recovered a mean of 15% of their deficit, while those with scores more than 2 recovered a mean of 77%. Admission status correlated significantly with spinal canal narrowing but not with vertebral body displacement. Time of treatment had no significant effect upon admission status and percent recovery. No significant difference in the percent of recovery was noted, whether decompression was early (up to 8 hours) or late (9 to 48 hours) after injury. Surgery did not significantly alter the percent of recovery. The findings indicate that the initial injury to the cervical spinal cord and spine remains the primary determinant of neurological outcome. Severe canal narrowing with cord compression thereafter appears to have comparatively little effect. The conclusion that decompression is without effect is not possible without comparison with a group of patients whose spinal canals remained narrowed at follow-up review.

Relation of hypesthesia to the outcome of glycerol rhizolysis for trigeminal neuralgia

1990 ◽  
Vol 72 (1) ◽  
pp. 55-58 ◽  
Author(s):  
K. Singh Sahni ◽  
Daniel R. Pieper ◽  
Randy Anderson ◽  
Nevan G. Baldwin
Keyword(s):  
Trigeminal Neuralgia ◽  
Corneal Ulceration ◽  
General Belief ◽  
Content Type ◽  
Kaplan Meier ◽  
Classical Trigeminal Neuralgia ◽  
Significant Difference ◽  
Glycerol Rhizolysis

✓ The effects of percutaneous retrogasserian glycerol rhizolysis were observed in a population of 58 cases of classical trigeminal neuralgia. The follow-up period ranged from 7 to 52 months postoperatively. It was noted that 84% of the patients had immediate relief of pain. The overall recurrence rate was 29%. Based on Kaplan-Meier survival curves, the overall half-life (T½) of this procedure was 16 months. Although none of the patients developed anesthesia dolorosa or corneal ulceration, one group of patients developed either a clinical or subclinical persistent “minimal hypesthesia.” In these there was a statistically significant difference in the T½ associated with this procedure (p = 0.01). This finding suggests that, contrary to the general belief, persistent hypesthesia after glycerol rhizolysis is a negative indicator of long-term success.

Seizure outcome in patients with surgically treated cerebral arteriovenous malformations

1993 ◽  
Vol 78 (1) ◽  
pp. 5-11 ◽  
Author(s):  
David G. Piepgras ◽  
Thoralf M. Sundt ◽  
Ashvin T. Ragoonwansi ◽  
Lorna Stevens
Keyword(s):  
Arteriovenous Malformations ◽  
The United States ◽  
Seizure Disorder ◽  
Seizure Outcome ◽  
Cerebral Arteriovenous Malformations ◽  
Content Type ◽  
Follow Up Study ◽  
Significant Difference ◽  
Fine Print

✓ A series of 280 cases of cerebral arteriovenous malformations (AVM's) treated surgically between June, 1970, and June, 1989, is reviewed with particular focus on the preoperative seizure history and follow-up seizure status. Follow-up evaluation (mean duration 7.5 years) was achieved in 98% of cases and was accomplished through re-examinations, telephone interviews, and written questionnaires. Overall, 89% of the surviving patients with a follow-up period of greater than 2 years were free of seizures at last examination. Of the 280 patients in this series. 163 had experienced no seizures preoperatively. A recent follow-up study (with a minimum duration of 2 years or to death) was available in 157 of these 163 cases; 21 patients had died. Of the 136 surviving patients, only eight (6%) were having new ongoing seizures. In the 128 (94%) who had remained seizure-free, 73% were receiving no anticonvulsant agents while 27% were taking anticonvulsant prophylaxis. The 2-year minimum follow-up study in 110 of the 117 patients with preoperative seizures revealed that eight (7%) had died. Of the 102 surviving patients, 85 (83%) were seizure-free (with 48% no longer receiving anticonvulsant therapy), while 17 (17%) still suffered intermittent seizures. However, of these 17 patients, 13 reported their seizures to be improved compared to preoperatively; the seizures were the same in two patients and were worse in two patients. An actuarial analysis was conducted comparing the life expectancy of patients following surgery for AVM's with the expected survival of a general white population of the same age and sex in the West Northcentral region of the United States. No statistically significant difference was found. There were seven perioperative deaths (three from cerebral hemorrhage, two from pulmonary emboli, and two from obstruction of venous drainage) and 22 deaths during the follow-up period. Of these 22 deaths, the cause was unknown in four patients, apparently unrelated to the AVM in 13, and directly or indirectly related to the patient's neurological condition prior to surgery or due to surgery performed for resection of the AVM in five. There was a statistically significant relationship between the size and location of the AVM and the clinical presentation. Patients with small AVM's (< 3 cm) were more likely to present with hemorrhage whereas those with large AVM's were more likely to present with seizures. Conclusions from this study are: 1) there is a low incidence of a new seizure disorder following surgery: 2) chances for resolution or control of a pre-existing seizure disorder are good: 3) although resolution of seizures or seizure control was achieved postoperatively in AVM's of all sizes, this benefit was highest in smaller as opposed to larger AVM's; and 4) ultimately, there is a good capacity for recovery from pre-existing neurological deficits or those resulting from surgery.

Medulloblastoma in childhood: an epidemiological study

1984 ◽  
Vol 61 (4) ◽  
pp. 657-664 ◽  
Author(s):  
Jacqueline R. Farwell ◽  
George J. Dohrmann ◽  
John T. Flannery
Keyword(s):  
Mortality Rate ◽  
Survival Rates ◽  
Female Ratio ◽  
Tumor Registry ◽  
Content Type ◽  
Probability Of Survival ◽  
Number Of Children ◽  
Male To Female ◽  
Fine Print

✓ The authors have reviewed 143 cases of medulloblastoma in children aged 19 years or younger who were treated in a 42-year period and reported in the Connecticut Tumor Registry. About 20 cases have occurred in each 5-year period since 1950, but 31 were seen between 1955 and 1959. Correspondingly, an excessive number of children born in the period 1954 to 1958 have developed medulloblastomas. A relationship to polio vaccine contaminated with SV40 virus may exist. Children with medulloblastomas had an increased number of immediate family members with brain tumors, leukemia, and childhood cancer when compared to controls. In this series, the male to female ratio was 1.33:1. Average age at diagnosis was 6½ years, with most children being diagnosed at 3 years old and fewer cases appearing in each successive hemidecade from birth to 20 years of age. Probability of survival at 6 months was 0.687; at 1 year, 0.444; at 2 years, 0.314; and at 5 years, 0.222. Survival probability was statistically significantly better in the years 1968 to 1977 than in previous decades, in part due to fewer autopsy diagnoses and lowered operative mortality, but also due to a decreased mortality rate in children several years after diagnosis. Fifty-one percent were treated with operation and irradiation, 17% with operation alone, 12% with irradiation alone, and 5% with operation, irradiation, and chemotherapy. Fifteen percent were not treated. One- and 5-year survival rates in patients with operation and irradiation were, respectively, 0.615 and 0.307; with operation, 0.125 and 0.042; with irradiation, 0.688 and 0.277; and with operation, irradiation, and chemotherapy, 0.857 and 0.643. All seven children who received chemotherapy were diagnosed after 1968, and five are still alive. Perhaps due to short follow-up time, the course and mortality rate of children treated with all three modalities were not statistically significantly different from those of children treated since 1968 with operation and radiation therapy.

Sign in / Sign up

Export Citation Format

Share Document