Cryosurgery re-visited for the removal and destruction of brain, spinal and orbital tumours

Advances in neuroimaging and cryosurgical techniques have prompted us to re-evaluate the potential of cryosurgical techniques for the removal and the destruction of various neoplasms. We have used cryosurgical instrumentation to remove tumours in the brain, spine and orbit in 71 patients without complications. Cryosurgery was used to facilitate removal and extraction in 64 and to destroy residual neoplasms when removal was incomplete in 7. Intraoperative real time ultrasonic imaging permitted precise delimitation of tumours from surrounding tissues and allowed monitoring during the production of cryosurgical lesions thus permitting heretofore unavailable visualization of the production of cryogenic lesions in the central nervous system. New cryosurgical instrumentation was used to produce lesions up to three times larger than similar sized probes previously available. Our results reconfirm that cryosurgery facilitates the removal of tumours in the brain, spinal cord and orbit, reduces blood loss in vascular tumours, and is effective in ablating residual neoplasms involving the superior sagittal sinus, torcula and parasagittal areas. A Doppler flowmeter proved useful for monitoring sagittal sinus blood flow during the production of cryosurgical ablation of residual tumour attached to the walls of the sagittal sinus. Recent advances in ultrasonic and neuroimaging coupled with stereotactic techniques and improvements in cryosurgical instrumentation may prove useful in the future percutaneous destruction of selective intracranial neoplasms.

Unique challenges of obtaining regulatory approval for a multicenter protocol to study the genetics of RRP and suggested remedies

Objective

Investigations that seek to generalize findings or to understand uncommon diseases must be conducted at multiple centers. This study describes the process of obtaining regulatory approval for a minimal risk genetic study in a multi-center setting as undertaken by the Recurrent Respiratory Papillomatosis (RRP) Task Force.

Study Design and Setting

Sequential cohort of American children's hospitals. A single protocol was submitted to each Institutional Review Board (IRB).

Results

Documentation was prepared for 14 IRBs over 2.5 years. The median time between enlistment and approval at the first 8 sites was 15 months. Institutions varied considerably in their requirements and in the issues that were raised. Protocols were submitted sequentially and accumulated experience was used in the preparation of applications to subsequent IRBs. Nevertheless, there was no correlation between the accumulated experience and the number of issues that were raised.

Conclusion

Despite uniform federal standards, all local IRBs required unique and individualized submissions. For multicenter studies, investigators should seriously consider the establishment of cooperative authorization agreements. On a simpler level, a standardized format for applications needs to be adopted nationwide. EBM rating: B-3b

Estimating the Additive Benefit of Surgical Excision to Stereotactic Radiosurgery in the Management of Metastatic Brain Disease

BACKGROUND:

There are limited data on the benefits of surgical tumor resection plus stereotactic radiosurgery (SRS) in comparison with SRS alone for patients with oligometastatic brain disease.

OBJECTIVE:

To determine the benefit of adding resection to SRS.

METHODS:

We reviewed 162 consecutive patients with oligometastatic brain disease, who underwent surgical tumor resection and SRS boost (n = 49) or SRS alone (n = 113). Patients receiving prior whole brain radiation therapy were excluded. Factors related to patient survival and time-to-local recurrence (TTLR) were determined by Cox regression. The effect of complete resection + SRS boost on survival was further explored by propensity score matching.

RESULTS:

The average age of the cohort was 65.3 years, it was 49.4% female, and included 260 brain tumors, of which 119 tumors were single. Seventy-three brain tumors recurred (28%). TTLR was related to radiation-sensitive pathology (hazards ratio [HR] = 0.34, P = .001), treatment volume (HR = 1.078/mL, P = .002), and complete tumor resection (HR = 0.37, P = .015). Factors related to survival were age (HR = 1.21/decade, P = .037), Eastern Cooperative Oncology Group performance score (HR = 1.9, P = .001), and complete surgical resection (HR = 0.55, P = .01). Propensity score matched analysis of complete surgical resection + SRS boost (n = 40) vs SRS alone (n = 80) yielded nearly identical survival results (HR = 0.52, P = .030) compared with the initial unmatched sample. Incomplete tumor resection had both median survival and TTLR equivalent to SRS alone.

CONCLUSION:

Complete surgical resection + SRS boost is associated with improved survival and reduced likelihood of local tumor recurrence in comparison with SRS alone. Incomplete resection did not improve survival or TTLR compared with SRS alone.

Relapsing multiple sclerosis patients treated with disease modifying therapy exhibit highly variable disease progression: a predictive model

OBJECTIVE

To describe a "new natural history" of multiple sclerosis (MS), characterizing three patterns of progression in Relapsing MS (RMS) patients during the "treatment era," using newly developed definitions. By utilizing our simple model we intend to predict which patients are most likely to reach an EDSS of 6.0.

METHODS

We stratified MS progression into three distinct patterns: aggressive MS (AMS), intermediate MS (IMS) and mild MS (MMS), based on Expanded Disability Status Scale (EDSS) score rate of change. These groups were compared for progression of EDSS before and after reaching these definitions.

RESULTS

The three groups remained significantly different in terms of disability throughout their disease courses p ≤ 0.001; 98% of the patients used disease modifying treatments (DMTs). AMS patients represent a significantly more disabling and aggressive form of MS than the IMS group.

CONCLUSIONS

Transition from relatively mild MS to aggressive course may begin at any time in the first 15 years, despite DMTs. Our definition for AMS is unique and identifies a group of patients who become permanently disabled within two years after a variable amount of time in a benign phase, despite treatment with modern DMTs.

Cervical spine clearance in the traumatically injured patient: is multidetector CT scanning sufficient alone? Clinical article

OBJECT

Clearance of the cervical spine in patients who have sustained trauma remains a contentious issue. Clinical examination alone is sufficient in neurologically intact patients without neck pain. Patients with neck pain or those with altered mental status or a depressed level of consciousness require further radiographic evaluation. However, no consensus exists as to the appropriate imaging modality. Some advocate multidetector CT (MDCT) scanning alone, but this has been criticized because MDCT is not sensitive in detecting ligamentous injuries that can often only be identified on MRI.

METHODS

Patients were identified retrospectively from a prospectively maintained database at a Level I trauma center. All patients admitted between January 2004 and June 2011 who had a cervical MDCT scan interpreted by a board-certified radiologist as being without evidence of acute traumatic injury and who also had a cervical MRI study obtained during the same hospital admission were included. Data collected included patient demographics, mechanism of injury, Glasgow Coma Scale score at the time of MRI, the indication for and findings on MRI, and the number, type, and indication for cervical spine procedures.

RESULTS

A total of 1004 patients were reviewed, of whom 614 were male, with an overall mean age of 47 years. The indication for MRI was neck pain in 662 patients, altered mental status in 467, and neurological signs or symptoms in 157. The MRI studies were interpreted as normal in 645 patients, evidencing ligamentous injury alone in 125, and showing nonspecific degenerative changes in the remaining patients. Of the 125 patients with ligamentous injuries, 66 (52.8%) had documentation of clearance (29 clinical, 37 with flexion-extension radiographs). Another 32 patients were presumed to be self-cleared, bringing the follow-up rate to 82% (98 of 119). Five patients died prior to clearance, and 1 patient was transferred to another facility prior to clearance. Based on these data, the 95% confidence interval for the assertion that clinically irrelevant ligamentous injury in the face of normal MDCT is 97%-100%. No patient with ligamentous injury on MRI was documented to require a surgical procedure or halo orthosis for instability. Thirty-nine patients ultimately underwent cervical surgical procedures (29 anterior and 10 posterior; 5 delayed) for central cord syndrome (21), quadriparesis (9), or discogenic radicular pain (9). None had an unstable spine.

CONCLUSIONS

In this study population, MRI did not add any additional information beyond MDCT in identifying unstable cervical spine injuries. Magnetic resonance imaging frequently detected ligamentous injuries, none of which were found to be unstable at the time of detection, during the course of admission, or on follow-up. Magnetic resonance imaging provided beneficial clinical information and guided surgical procedures in patients with neurological deficits or radicular pain. An MDCT study with sagittal and coronal reconstructions negative for acute injury in patients without an abnormal motor examination may be sufficient alone for clearance.

The shifting landscape of metastatic breast cancer to the CNS

The improved survival following the diagnosis of breast cancer has potentially altered the characteristics and course of patients presenting with CNS involvement. We therefore sought to define our current cohort of breast cancer patients with metastatic disease to the CNS in regard to modern biomarkers and clinical outcome. Review of clinical and radiographic records of women presenting to a tertiary medical center with the new diagnosis of CNS metastatic disease from breast cancer. This was a retrospective review from patients identities obtained from two prospective databases. There were 88 women analyzed who were treated over the period of January 2003 to February 2010, average age 56.9 years. At the time of initial presentation of CNS disease, 68 % of patients had multiple brain metastases, 17 % had a solitary metastasis, and 15 % had only leptomeningeal disease (LMD). The median survival for all patients from the time of diagnosis of breast disease was 50.0 months, and 9.7 months from diagnosis of CNS involvement. The only factor related to overall survival was estrogen receptor-positive pathology (57.6 v. 38.2 months, p = .02 log-rank); those related to survival post CNS diagnosis were presentation with LMD (p = .004, HR = 3.1, Cox regression) and triple-negative hormonal/HER2 status (p = .02, HR = 2.3, Cox regression). Patients with either had a median survival of 3.1 months (no patients in common). Of the 75 patients who initially presented with metastatic brain lesions, 20 (26 %) subsequently developed LMD in the course of their disease (median 10.4 months), following which survival was grim (1.8 months median). Symptoms of LMD were most commonly lower extremity weakness (14/33), followed by cranial nerve deficits (11/33). The recently described Graded Prognostic Assessment (GPA) tumor index stratified median survival at 2.5, 5.9, 13.1, and 21.7 months, respectively, for indices of 1-4 (p = .004, log-rank), which contrasted with the nonsignificant survival difference between Radiation Therapy Oncology Group Recursive Partitioning Analysis classes one and two. (13.1 v. 13.2, p = .8, log-rank). Treatment of patients with metastatic brain disease from breast cancer should be tailored to the patient's hormonal status and GPA index. Practitioners must be vigilant for the development of LMD, especially as it often presents with nondescript complaints such as back pain.

The prognostic significance of traumatic brainstem injury detected on T2-weighted MRI

Object

Magnetic resonance imaging is frequently used to evaluate patients with traumatic brain injury in the acute and subacute setting, and it can detect injuries to the brainstem, which are often associated with poor outcomes. This study was undertaken to determine which MRI and clinical factors provide prognostic information in patients with traumatic brainstem injuries.

Methods

The authors performed a retrospective analysis of cases involving patients admitted to a Level I trauma center who were identified in a prospective database as having suffered traumatic brainstem injury identified on MRI. Patient outcomes were dichotomized to dead/vegetative versus functional groups. Standard demographic data, admission Glasgow Coma Scale (GCS) scores, results of the motor component of the GCS examination at admission and 24 hours later, CT scan findings, and peak intracranial pressure were collected from medical records. Volumetric analysis of each patient's injuries was performed with T2-weighted and gradient echo sequences. The T2-weighted MRI sequence for each patient was reviewed to determine the anatomical location of injury within the brainstem and whether the injury crossed the midline.

Results

Thirty-six patients who met the study inclusion criteria were identified. At 6-month follow-up, 53% of these patients had poor outcomes and 47% had recovered. Patients with injuries to the medulla or deep bilateral injuries to the pons did not recover. The T2 volumes were found superior to gradient echo sequences in regard to predicting survival (ROC/AUC 0.67, p = 0.07 vs 0.60, p = 0.29, respectively), but neither reached statistical significance. The timing of MR image acquisition did not influence the findings. The time from admission to MRI did not differ significantly between the recovered group and the poor-outcome group (p = 0.52, Mann-Whitney test), and lesion size as measured by T2 volume did not vary with time to scan (R2 = 0.03, p = 0.3, linear regression). Performing a stepwise logistic regression with all the variables yielded the following factors related to recovery: crossing midline, p = 0.0156, OR 0.075; and 24-hour GCS motor score, p = 0.0045, OR = 2.25, c-statistic 0.913. Further examination of these 2 factors disclosed the following: none of 15 patients with midline-crossing lesions and a 24-hour GCS motor score of 4 or less recovered; conversely, 12 of 13 patients with lesions that did not cross midline recovered, regardless of GCS motor score.

Conclusions

Bilateral injury to the pons and medulla as detected on T2-weighted MRI sequences was associated with poor outcome in patients with brainstem injuries; T2 volumes were found superior to gradient echo sequences in regard to predicting survival, but neither reached statistical significance. When MRI findings were coupled with clinical examination findings, a strong correlation existed between poor outcome and the combination of bilateral brainstem injury and a motor GCS score of 4 or less 24 hours after admission.

Distribution of the h-index in radiation oncology conforms to a variation of power law: implications for assessing academic productivity

Leaders of academic institutions evaluate academic productivity when deciding to hire, promote, or award resources. This study examined the distribution of the h-index, an assessment of academic standing, among radiation oncologists. The authors collected h-indices for 826 US academic radiation oncologists from a commercial bibliographic database (SCOPUS, Elsevier B.V., NL). Then, logarithmic transformation was performed on h-indices and ranked h-indices, and results were compared to estimates of a power law distribution. The h-index frequency distribution conformed to both the log-linear variation of a power law (r (2) = .99) and the beta distribution with the same fitting exponents as previously described in a power law analysis of the productivity of neurosurgeons. Within radiation oncology, as in neurosurgery, there are exceedingly more faculty with an h-index of 1-2. The distribution fitting the same variation of a power law within two fields suggests applicability to other areas of academia.

Abstract 2940: Arrival in the Emergency Department on Nights and Weekends Results in Delayed Administration of Intravenous Thrombolysis for Ischemic Stroke

Background: Reduced time to administration of intravenous thrombolysis for acute ischemic stroke (AIS) is associated with improved functional outcomes. Less than one-third of AIS patients receive IV rt-PA with a door-to-needle (DTN) ≤ 60 minutes with only modest improvements reported over time. We investigated factors that may adversely prolong DTN time including reduced resident physician experience, low stroke severity on presentation, patient presentation time (day, evening, night) and day of week.

Methods: A consecutive series of 258 patients with AIS received IV rt-PA at an academic comprehensive stroke center with a developed process for IV rt-PA administration and a neurology training program. Patient presentation times in the emergency department were divided into shifts defined as 07:00-14:59 (day), 15:00-22:59 (evening) and 23:00-06:59 (night). Neurology resident experience level was grouped as July-December (less experienced) vs. January-June (more experienced). Day of the week was grouped into weekday (Monday-Friday) and weekend (Saturday-Sunday). Variables associated with DTN time were assessed by t-test, ANOVA and by logistic regression.

Results: The group had a mean age of 70.7±14.3 years, NIHSS score 13.3±6.8, DTN time 70.0±28.1 minutes, onset to ED arrival time 77.5±38.0 minutes. Patients presenting during evening and night hours had prolonged DTN times, day=65.5, evening=71.8 and night=78.3 minutes (p=0.05) by ANOVA. Patients arriving on weekends also had prolonged DTN times weekdays= 66.6 vs. weekends=77.2 minutes (p=.01). Increased time from onset to ED arrival was also associated with reduced DTN time (p<0.001). Age, gender, race, stroke severity on presentation, and resident experience level were not related to DTN time. Both presentation time by shift and day of week were predictive of prolonged DTN time by multivariable analysis (p<0.01).

Conclusions: Presentation time during the evening and night hours and weekends is associated with prolonged DTN times. Reduced staffing and support on nights and weekends may adversely affect DTN time.

Abstract 93: Relation Between Outcome and Infarct Size and Location in Brainstem Stroke

Introduction: Although MR is frequently used for the diagnosis of brainstem stroke, there is little consensus regarding the ultimate prognostic implications of the findings.

Hypothesis: MR imaging characteristics will be useful in the determination of outcome following brainstem infarction.

Methods: We performed a retrospective review of patients treated for basilar distribution infarction at a Joint Commission Certified Primary Stroke Center and identified through a prospective registry begun in 8/06. Standard demographic and clinical data were recorded on admission and MR scans analyzed. Routine 5mm T2 and DWI sequences were utilized starting at the level of the P2 vessel, comprising 2 midbrain, 3 pontine and 3 medullary slices. Volumes were computed by manually tracing the signal abnormality and employing the supplied software package (Carestream PACS, Rochester NY). Outcomes were dichotomized as non-functional (dead, comatose, locked-in) and functional (all others) at 6 months.

Results: There were 38 patients in the registry, of whom 25 had MR documented brainstem infarctions. There were 11/14 M/F, average age 64.7 years. Average admit NIHSS was 17.4 and the LOS was 21.5 days. MR was performed at a median of 1 day post admission. Mid-pontine was the most common stroke location (19/25) and about half of the DWI lesions (12/25) crossed midline. Outcome was deceased in 8 (5 in-hospital, 3 hospice), 4 locked-in and 13 functional survivors. Both T2 and DWI volumes correlated with outcome (p<.0001), but DWI was slightly superior (AUC/ROC .865/.862). DWI volume, not T2, correlated with initial NIHSS (p=.05, linear regression). In the stepwise logistic regression, DWI volume alone correlated with functional survival (p=.0003), not age, admission NIHSS, midline-crossing lesions nor anatomic location. DWI volume predicted 86% of the variation in outcome (c-statistic) and no patient with a DWI volume >3cm3 had a functional outcome.

Conclusion: In this population of patients with brainstem stroke, MR appears to be a potent tool for predicting outcome with DWI volume being the most useful indicator.

P4-17-07: The Shifting Landscape of Metastatic Breast Cancer to the CNS

Introduction: Improved survival following the diagnosis of breast cancer, in conjunction with new therapies and diagnostics has potentially altered the characteristics and course of patients presenting with CNS involvement.

Methods: Review of clinical and radiographic records of women presenting to a tertiary medical center with the new diagnosis of CNS metastatic disease from breast cancer. This was a retrospective review from patients identities obtained from two prospective databases Results: There were 88 women analyzed who were treated over the period 1/2003-2/2010, average age 56.9. At the time of initial presentation of CNS disease, 68% of patients had multiple brain metastases, 17% had a solitary metastasis and 15% had only leptomeningeal disease (LMD). The median survival for all patients from the time of diagnosis of breast disease was 50.0 months, and 9.7 months from diagnosis of CNS involvement. The only factor related to overall survival was estrogen receptor positive (ER+) pathology (57.6 v. 38.2 months, p=.02 log-rank); those related to survival post CNS diagnosis were presentation with LMD (p=.004, HR= 3.1, Cox regression) and triple negative hormonal/HER2 status (p=.02, HR= 2.3, Cox regression). Patients with either had a median survival of 3.1 months (no patients in common). Of the 75 patients who initially presented with metastatic brain lesions, 20 (26%) subsequently developed LMD in the course of their disease (median 10.4 months), following which survival was grim (1.8 months median). Of note was that HER2+ status was protective in regard to late development of LMD (14.7 vs. 42.3%, p=.03, Chi-square). Symptoms of LMD were most commonly lower extremity weakness (14/33), followed by cranial nerve deficits (11/33).

Conclusion: Treatment of patients with metastatic brain disease from breast cancer should be tailored to the patient's hormonal status (as it markedly effects survival) and practitioners must be vigilant for the development of LMD, especially as it often presents with non-descript complaints such as back pain.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-17-07.

Chronic subdural hematoma in the elderly: not a benign disease

Object

Chronic subdural hematoma (CSDH) is perceived to be a “benign,” easily treated condition in the elderly, but reported follow-up periods are brief, usually limited to acute hospitalization.

Methods

The authors conducted a retrospective review of data obtained in a prospectively identified consecutive series of adult patients admitted to their institution between September 2000 and February 2008 and in whom there was a CT diagnosis of CSDH. Survival data were compared to life-table data.

Results

Of the 209 cases analyzed, 63% were men and the mean age was 80.6 years (range 65–96 years). Primary surgical interventions performed were bur holes in 21 patients, twist-drill closed-system drainage in 44, and craniotomies in 72. An additional 72 patients were simply observed. Reoperations were recorded in 5 patients—4 who had previously undergone twist-drill drainage and 1 who had previously undergone a bur hole procedure (p = 0.41, chi-square analysis). Thirty-five patients (16.7%) died in hospital, 130 were discharged to rehabilitation or a skilled care facility, and 44 returned home. The follow-up period extended to a maximum of 8.3 years (median 1.45 years). Six-month and 1-year mortality rates were 26.3% and 32%, respectively.

In the multivariate analysis (step-wise logistic regression), the sole factor that predicted in-hospital death was neurological status on admission (OR 2.1, p = 0.02, for each step). Following discharge, the median survival in the remaining cohort was 4.4 years. In the Cox proportional hazards model, only age (hazard ratio [HR] 1.06/year, p = 0.02) and discharge to home (HR 0.24, p = 0.01) were related to survival, whereas the type of intervention, whether surgery was performed, size of subdural hematoma, amount of shift, bilateral subdural hematomas, and anticoagulant agent use did not affect the long- or short-term mortality rate.

Comparison of postdischarge survival and anticipated actuarial survival demonstrated a markedly increased mortality rate in the CSDH group (median survival 4.4 vs 6 years, respectively; HR 1.94, p = 0.0002, log-rank test). This excess mortality rate was also observed at 6 months postdischarge with evidence of normalization only at 1 year.

Conclusions

In this first report of the long-term outcome of elderly patients with CSDH the authors observed persistent excess mortality up to 1 year beyond diagnosis. This belies the notion that CSDH is a benign disease and indicates it is a marker of other underlying chronic diseases similar to hip fracture.

Microvascular decompression for elderly patients with trigeminal neuralgia: a prospective study and systematic review with meta-analysis

OBJECT

Because the incidence of trigeminal neuralgia (TN) increases with age, neurosurgeons frequently encounter elderly patients with this disorder. Although microvascular decompression (MVD) is the only etiological therapy for TN with the highest initial efficacy and durability of all treatments, it is nonetheless associated with special risks (cerebellar hematoma, cranial nerve injury, stroke, and death) not seen with the commonly performed ablative procedures. Thus, the safety of MVD in the elderly remains a concern. This prospective study and systematic review with meta-analysis was conducted to determine whether MVD is a safe and effective treatment in elderly patients with TN.

METHODS

In this prospectively conducted analysis, 36 elderly patients (mean age 73.0 ± 5.9 years) and 53 nonelderly patients (mean age 52.9 ± 8.8 years) underwent MVD over the study period. Outcome and complication data were recorded. The authors also conducted a systematic review of the English literature published before December 2009 and providing outcomes and complications of MVD in patients with TN above the age of 60 years. Pooled complication rates of stroke, death, cerebellar hematoma, and permanent cranial nerve deficits were analyzed.

RESULTS

Thirty-one elderly patients (86.1%) reported an excellent outcome after MVD (mean follow-up 20.0 ± 7.0 months). Twenty-five elderly patients with Type 1 TN were compared with 26 nonelderly patients with Type 1 TN, and no significant difference in outcomes was found (p = 0.046). Three elderly patients with Type 2a TN were compared with 12 nonelderly patients with Type 2a TN, and no significant difference in outcomes was noted (p = 1.0). Eight elderly patients with Type 2b TN were compared with 15 nonelderly patients with Type 2b TN, and no significant difference in outcomes was noted (p = 0.086). The median length of stay between cohorts was compared, and no significant difference was noted (2 days for each cohort, p = 0.33). There were no CSF leaks, no cerebellar hematomas, no strokes, and no deaths. Eight studies (1334 patients) met the inclusion criteria for the meta-analysis. For none of the complications was the incidence significantly more frequent in elderly patients than in the nonelderly.

CONCLUSIONS

Although patient selection remains important, the authors' experience and the results of this systematic review with meta-analysis suggest that the majority of elderly patients with TN can safely undergo MVD.

Survey of the h index for all of academic neurosurgery: another power-law phenomenon?

Object

The h index is a recently developed bibliometric that assesses an investigator's scientific impact with a single number. It has rapidly gained popularity in the physical and, more recently, medical sciences.

Methods

The h index for all 1120 academic neurosurgeons working at all Electronic Residency Application Service–listed training programs was determined by reference to Google Scholar. A random subset of 100 individuals was investigated in PubMed to determine the total number of publications produced.

Results

The median h index was 9 (range 0–68), with the 75th, 90th, and 95th percentiles being 17, 26, and 36, respectively. The h indices increased significantly with increasing academic rank, with the median for instructors, assistant professors, associate professors, and professors being 2, 5, 10, and 19, respectively (p < 0.0001, Kruskal-Wallis; all groups significantly different from each other except the difference between instructor and assistant professor [Conover]). Departmental chairs had a median h index of 22 (range 3–55) and program directors a median of 17 (range 0–62). Plot of the log of the rank versus h index demonstrated a remarkable linear pattern (R2 = 0.995, p < 0.0001), suggesting that this is a power-law relationship.

Conclusions

A survey of the h index for all of academic neurosurgery is presented. Results can be used for benchmark purposes. The distribution of the h index within an academic population is described for the first time and appears related to the ubiquitous power-law distribution.

Microvascular decompression after failed Gamma Knife surgery for trigeminal neuralgia: a safe and effective rescue therapy?

Object

Stereotactic radiosurgical rhizolysis using Gamma Knife surgery (GKS) is an increasingly popular treatment for medically refractory trigeminal neuralgia. Because of the increasing use of GKS for trigeminal neuralgia, clinicians are faced with the problem of choosing a subsequent treatment plan if GKS fails. This study was conducted to identify whether microvascular decompression (MVD) is a safe and effective treatment for patients who experience trigeminal neuralgia symptoms after GKS.

Methods

From their records, the authors identified 29 consecutive patients who, over a 2-year period, underwent MVD following failed GKS. During MVD, data regarding thickened arachnoid, adhesions between vessels and the trigeminal nerve, and trigeminal nerve atrophy/discoloration were noted. Outcome and complication data were also recorded.

Results

The MVD procedure was completed in 28 patients (97%). Trigeminal nerve atrophy was noted in 14 patients (48%). A thickened arachnoid was noted in 1 patient (3%). Adhesions between vessels and the trigeminal nerve were noted in 6 patients (21%) and prevented MVD in 1 patient. At last follow-up, 15 patients (54%) reported an excellent outcome after MVD, 1 (4%) reported a good outcome, 2 (7%) reported a fair outcome, and 10 patients (36%) reported a poor outcome. After MVD, new or worsened facial numbness occurred in 6 patients (21%). Additionally, 3 patients (11%) developed new or worsened troubling dysesthesias.

Conclusions

Thickened arachnoid, adhesions between vessels and the trigeminal nerve, and trigeminal nerve atrophy/discoloration due to GKS did not prevent completion of MVD. An MVD is an appropriate and safe “rescue” therapy following GKS, although the risks of numbness and troubling dysesthesias appear to be higher than with MVD alone.

Microvascular decompression in patients with isolated maxillary division trigeminal neuralgia, with particular attention to venous pathology

OBJECT

The authors have the clinical impression that patients with isolated V2, or maxillary division, trigeminal neuralgia (TN) are most often women of a younger age with atypical pain features and a predominance of venous compression as the pathology. The aim of this study was to evaluate a specific subgroup of patients with V2 TN.

METHODS

Among 120 patients who underwent microvascular decompression (MVD) for TN in 2007, data were available for 114; 6 patients were lost to follow-up. Patients were stratified according to typical (Burchiel Type 1), mixed (Burchiel Type 2a), or atypical (Burchiel Type 2b) TN. A pain-free status without medication was used to determine the efficacy of MVD. All patients were contacted in June 2008 and again in January 2009 at 12-24 months after surgery (median 18.4 months) and asked to rate their response to MVD as excellent (complete pain relief without medication), fair (complete pain relief with medication or some relief with or without medication), or poor (continued pain despite medication; that is, no change from their preoperative baseline pain status.

RESULTS

Of 114 patients, 14 (12%) had isolated V2 TN. Among these 14 were 2 typical (14%), 1 mixed (7%), and 11 atypical cases (79%) of TN. Among the remaining 100 cases were 37 typical (37%), 14 mixed (14%), and 49 atypical cases (49%) of TN. In the isolated V2 TN group, all patients were women as compared with 72% of women in the larger group of 100 patients (p = 0.05, chi-square test). The average age in the isolated V2 TN group was 51.2 years (median 48.1 years) versus 54.2 years (median 54.0 years) in the remainder of the group (p = NS, unpaired Student t-test). In the isolated V2 TN group, there was a predominance of atypical pain cases (79%) versus 49% in the remainder of the group, and this finding trended toward statistical significance (p = 0.07, chi-square test). Venous contact or compression (partly or wholly) was noted in 93% of the patients with isolated V2 versus 69% of the remainder of the group (p = 0.13, chi-square test). The likelihood of excellent outcomes in the patients with V2 TN (71%) was compared with that in typical pain cases (79%) among patients in the rest of the group (that is, the bestoutcome group), and no difference was found between the 2 groups (p = 0.8, chi-square test).

CONCLUSIONS

The authors confirmed that patients with isolated V2 TN were more likely to be female, tended toward an atypical pain classification with venous pathology at surgery, and fared just as well as those presenting with typical pain.

Stereotactic radiosurgery boost to the resection bed for oligometastatic brain disease: challenging the tradition of adjuvant whole-brain radiotherapy

Object

Whole-brain radiation therapy (WBRT) has been the traditional approach to minimize the risk of intracranial recurrence following resection of brain metastases, despite its potential for late neurotoxicity. In 2007, the authors demonstrated an equivalent local recurrence rate to WBRT by using stereotactic radiosurgery (SRS) to the operative bed, sparing 72% of their patients WBRT. They now update their initial experience with additional patients and more mature follow-up.

Methods

The authors performed a retrospective review of all cases involving patients with limited intracranial metastatic disease (≤ 4 lesions) treated at their institution with SRS to the operative bed following resection. No patient had prior cranial radiation and WBRT was used only for salvage.

Results

From November 2000 to June 2009, 52 patients with a median age of 61 years met inclusion criteria. A single metastasis was resected in each patient. Thirty-four of the patients each had 1 lesion, 13 had 2 lesions, 3 had 3 lesions, and 2 had 4 lesions. A median dose of 1500 cGy (range 800–1800 cGy) was delivered to the resection bed targeting a median volume of 3.85 cm3 (range 0.08–22 cm3). With a median follow-up of 13 months, the median survival was 15.0 months. Four patients (7.7%) had a local recurrence within the surgical site. Twenty-three patients (44%) ultimately developed distant brain recurrences at a median of 16 months postresection, and 16 (30.7%) received salvage WBRT (8 for diffuse disease [> 3 lesions], 4 for local recurrence, and 4 for diffuse progression following salvage SRS). The median time to WBRT administration postresection was 8.7 months (range 2–43 months). On univariate analysis, patient factors of a solitary tumor (19.0 vs 12 months, p = 0.02), a recursive partitioning analysis (RPA) Class I (21 vs 13 months, p = 0.03), and no extracranial disease on presentation (22 vs 13 months, p = 0.01) were significantly associated with longer survival. Cox multivariate analysis showed a significant association with longer survival for the patient factors of no extracranial disease on presentation (p = 0.01) and solitary intracranial metastasis (p = 0.02). Among patients with no extracranial disease, a solitary intracranial metastasis conferred significant additional survival advantage (43 vs 10.5 months, p = 0.05, log-rank test). No factor (age, RPA class, tumor size or histological type, disease burden, extent of resection, or SRS dose or volume) was related to the need for salvage WBRT.

Conclusions

Adjuvant SRS to the metastatic intracranial operative bed results in a local recurrence rate equivalent to adjuvant WBRT. In combination with SRS for unresected lesions and routine imaging surveillance, this approach achieves robust overall survival (median 15 months) while sparing 70% of the patients WBRT and its potential acute and chronic toxicity.

Utility of intraoperative electromyography in microvascular decompression for hemifacial spasm: a meta-analysis

Object

In this paper, the authors' goal was to determine the utility of monitoring the abnormal muscle response (AMR) or “lateral spread” during microvascular decompression surgery for hemifacial spasm.

Methods

The authors' experience with AMR as well as the data available in the English-language literature regarding resolution or persistence of AMR and the resolution or persistence of hemifacial spasm at follow-up was pooled and subjected to a meta-analysis.

Results

The pooled OR revealed by the meta-analysis was 4.2 (95% CI 2.7–6.7). The chance of a cure if the AMR was abolished during surgery was 4.2 times greater than if the lateral spread persisted.

Conclusions

The AMR should be monitored routinely in the operating room, and surgical decision-making in the operating room should be augmented by the AMR.

Exclusion of cervical spine instability in patients with blunt trauma with normal multidetector CT (MDCT) and radiography

The objective of the study was to determine if negative multidetector computed tomography (MDCT) and lateral radiography of the cervical spine effectively excludes patients with unstable cervical spine injuries. Over a period of 40 months, 6558 people were admitted to our trauma service with blunt injury and 447 (6.8%) were found to have cervical fractures. Fractures were identified by CT and/or lateral radiography. In order to rule out clinically significant instability in the absence of fracture, we identified nine patients who required any type of stabilization of the cervical spine including anterior fusion, posterior fusion and external orthosis. These patients also underwent MR of the cervical spine. Radiography, CT, and MR images and reports of these nine patients were reviewed. Nine patients without a fracture required cervical stabilization. These patients had the following abnormalities: disc herniation with canal stenosis in three, unilateral jumped facet in three, and various other soft tissue abnormalities in three, all of which were evident on CT or radiography. All nine patients had evidence for cervical spine injury or instability by MDCT. Normal MDCT and radiography appears adequate to 'clear' the cervical spine. We recommend that patients requiring cervical spine clearance undergo a complete MDCT and lateral radiograph of the cervical spine. If these studies are entirely normal, then the cervical spine may be cleared. If any abnormalities, including disc herniation, soft tissue swelling and bony malalignments are noted by radiography and/or MDCT, further studies, including MR, are indicated prior to clearance of the cervical spine.

Nutritional supplementation in monochorionic diamniotic twin pregnancies: impact on twin-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) has been related to unbalanced unidirectional arteriovenous anastomoses in the placenta of monochorionic diamniotic (DiMo) twin gestations. As maternal malnutrition accounting for hypoproteinemia and anemia has been detected in severe cases of TTTS, the purpose of this study was to evaluate the impact of early diet supplementation on TTTS. Fifty-one DiMo twin pregnancies were given commercially available oral nutritional diet supplements and then compared in a retrospective cohort study to 52 twin gestations with the same chorionicity but not subjected to nutritional supplementation. Diet supplementation was associated with lower overall incidence of TTTS (20/52 versus 8/51, P = 0.02) and with lower prevalence of TTTS at delivery (18/52 versus 6/51, P = 0.012) when compared with no supplementation. Nutritional intervention also significantly prolonged the time between the diagnosis of TTTS and delivery (9.4 +/- 3.7 weeks versus 4.6 +/- 6.5 weeks; P = 0.014). The earlier nutritional regimen was introduced, the lesser chance of detecting TTTS ( P = 0.001). Although not statistically significant, dietary intervention was also associated with lower Quintero stage, fewer invasive treatments, and lower twin birth weight discordance. Diet supplementation appears to counter maternal metabolic abnormalities in DiMo twin pregnancies and improve perinatal outcomes in TTTS when combined with the standard therapeutic options.

Hydrogel coil–related delayed hydrocephalus in patients with unruptured aneurysms

Object

Because of high recanalization rates associated with wide-necked intracranial aneurysms treated with bare platinum coils, hydrogel coils (HydroCoil, MicroVention, Inc.) have been developed. Hydrogel coils undergo progressive expansion once exposed to the physiological environment of blood and increase overall aneurysm filling.

Methods

The authors retrospectively reviewed their series of patients with unruptured aneurysms treated between 1998 and 2006 and who underwent placement of bare platinum and hydrogel coils for cerebral aneurysms. They examined the incidence of delayed hydrocephalus as related to coil type. In a subgroup of patients in which preand postprocedure CT and MR imaging studies were available, the authors quantitatively analyzed the ventricular size change after hydrogel coils were placed.

Results

Four of 29 patients treated with hydrogel coils developed symptomatic hydrocephalus 2–6 months after the intervention compared with 0 of 26 treated with bare platinum coils alone. The difference in ventricular size between the subgroups in which pre- and postprocedure imaging was performed was found to be statistically significant (p < 0.05). All 4 HydroCoil-treated patients in whom hydrocephalus developed required placement of a shunt.

Conclusions

A 14% incidence (95% confidence interval 3.9–31.7%) of hydrocephalus in patients with unruptured aneurysm undergoing embolization with hydrogel coils was discovered. This incidence is much higher than previously reported. The mechanism by which hydrogel coils may induce hydrocephalus remains poorly understood.

Single session stereotactic radiosurgery boost to the post-operative site in lieu of whole brain radiation in metastatic brain disease

PURPOSE

Whole brain radiation (WBXRT) reduces the incidence of local and distant recurrence following resection of metastatic brain disease but does not prolong life and may entail neurocognitive decline. We employed a novel treatment modality of providing a single-session stereotactic radiosurgery (SRS) boost to the surgical resection site to achieve local control without the risk of cognitive effects.

METHODS

We reviewed all patients at our institution that were treated with SRS to the post-operative bed following resection of a metastatic brain deposit.

RESULTS

There were 32 patients identified (16 F) and median age was 60 years. One lesion was resected in all patients of whom 21 were solitary (eight with two lesions, three with three). Median survival was 16.4 months with a 14 month median follow-up. Factors which improved survival were solitary tumor, age <65 and RPA 1, although none achieved statistical significance. In the Cox multivariate analysis only smaller post-operative treatment volume correlated with survival (P = .04). There were two local recurrences (6.25%) to the surgical site and four patients required SRS for new lesions. Nine patients ultimately required salvage WBXRT (3/21 solitary v. 6/11 multiple lesions, P = .03 chi(2)), two for local recurrence post resection and seven for diffuse new disease.

CONCLUSION

The use of SRS to the surgical site results in local recurrence rates comparable to WBXRT and is associated with excellent survival. Over 70% of patients managed this way were spared WBXRT. The presence of multiple lesions on presentation is predictive of the need for subsequent salvage WBXRT.

Long-term survival enhanced by cordectomy in a patient with a spinal glioblastoma multiforme and paraplegia. Case report

Spinal glioblastomas multiforme (GBMs) are rare lesions of the central nervous system with a prognosis as poor as that of their intracranial counterpart. The authors present a case of a 50-year-old man with a GBM of the spinal cord treated with surgical removal of the mass and cordectomy after the onset of paraplegia. Six years later, the patient developed hepatitis C and received interferon therapy. Six months after the start of interferon therapy, magnetic resonance imaging revealed a right cerebellar mass pathologically consistent with a GBM. Despite aggressive treatment, the patient died 1 month later. Although intracranial dissemination of spinal GBMs has been reported, this case illustrates the longest reported interval between the occurrence of a spinal GBM and its intracranial dissemination. Thus, cordectomy should be considered as a reasonable alternative in patients with complete loss of neurological function at and below the level where they harbor a malignant spinal cord astrocytoma.

Relation among aneurysm size, amount of subarachnoid blood, and clinical outcome

Object

The authors of recent reports have suggested that smaller aneurysms are associated with more extensive sub-arachnoid hemorrhage (SAH), which could potentially presage poor outcome in patients harboring these lesions. The authors reviewed their clinical experience to determine if this theory has a basis in truth.

Methods

The authors undertook a retrospective review of a consecutive series of patients with aneurysmal SAH. Computed tomography scans and angiograms were studied to establish SAH scores and aneurysm size.

Results

One hundred thirty-three patients were treated during a 2-year period (January 2003–December 2004). There were 101 female and 32 male patients whose mean age was 56.7 years. The location distribution of aneurysms that bled was as follows: anterior communicating artery (56 cases), posterior communicating artery (34 cases), middle cerebral artery (21 cases), posterior circulation (16 cases), and paraclinoid region (six cases). The mean aneurysm size was 6.2 mm (range 2–26 mm). The mean SAH score was 18.3 (not normally distributed, p < 0.01, D'Agostino–Pearson test). One hundred three patients underwent surgical exploration and placement of an aneurysm clip, 21 underwent deployment of a coil, and two underwent both therapies; seven patients died prior to intervention.

No correlation was found between aneurysm size and SAH score (rS = −0.023, p = 0.8) or between small aneurysm size and poor Glasgow Outcome Scale score (p = 0.13). In fact, the trend was the opposite. The SAH score did, however, correspond strongly with the admission Hunt and Hess grade (p < 0.0001), indicating the strong correlation between grade and volume of intracranial blood. Outcome was best explained in the multivariate analysis by the following factors: admission Hunt and Hess grade, age, and clinical vasospasm (p < 0.0001) with the proportion of cases correctly classified as 79.7%.

Conclusions

Evaluation of the results in the present clinical series suggests that there is no relation between aneurysm size and volume of subarachnoid blood. The volume of cisternal blood correlates with Hunt and Hess grade but is not an independent determinant of outcome. Outcome is related to the following triad of well-established clinical factors: Hunt and Hess grade, age, and clinical vasospasm.

Some speculation on the origin of glioblastoma

Glioblastoma, the most common primary brain tumor, is also the most deadly, with median survival of about one year, which is little improved over the last five decades. Its pathogenesis is a vexing problem. Despite extensive basic and clinical scientific research, little is known regarding the cause of this disease, the genetic factors which drive its course, or any strategies which may result in effective treatment. This persistent resistance to understanding suggests to the authors that some of the fundamental assumptions regarding the disease are likely to be flawed, and that a new paradigm must be sought to replace them. This manuscript is a review of some of what is known regarding this disease, and then presents a series of hypotheses which compromise an alternative view of glioblastoma.

Central brain herniation secondary to fulminant acute disseminated encephalomyelitis: implications for neurosurgical management

✓ Acute disseminated encephalomyelitis (ADEM), also known as postinfectious encephalomyelitis, is an immunologically mediated demyelinating disorder affecting the central nervous system that typically occurs after infection or vaccination. The prognosis of ADEM is generally favorable. In a small subset of patients with ADEM, however, fulminant cerebral edema requiring neurosurgical intervention will develop. Few recommendations are available to help the neurosurgeon in dealing with such cases. In this report, the authors present the case of a patient with ADEM in whom central brain herniation developed secondary to medically intractable cerebral edema. The authors review the salient features of the disease and suggest a role for neurosurgeons in cases of fulminant ADEM.

Thoracolumbar syrinx in association with Williams syndrome

Williams syndrome is a genetic condition caused by a deletion on chromosome 7. Clinically it consists of multiple cardiovascular and craniofacial structural abnormalities as well as developmental delay, specific cognitive difficulties, and a characteristic personality. Although scoliosis is a noted manifestation of the disorder, syrinx in association with Williams syndrome has not been reported previously in the literature. Here we present the case of a child with Williams syndrome, scoliosis, and a thoracolumbar syrinx that was successfully treated surgically. We recommend that children with Williams syndrome and scoliosis undergo preoperative evaluation of the spinal cord, as well as the spinal column, so that correctable lesions such as a syrinx are not overlooked. Although syrinxes are often associated with scoliosis, the association in this case of syrinx and Williams syndrome could imply the existence of a genetic contribution to syrinx formation on chromosome 7.

Primary Treatment of a Blister-like Aneurysm with an Encircling Clip Graft: Technical Case Report

OBJECTIVE:

Blister-like aneurysms at nonbranching sites in the supraclinoid portion of the internal carotid artery are a rare but important cause of subarachnoid hemorrhage. We report a case of subarachnoid hemorrhage caused by a ruptured blister-type aneurysm, review the pertinent literature, and hope to remind readers of the wisdom of the use of an encircling clip as the primary treatment of these challenging lesions.

CLINICAL PRESENTATION:

A 41-year-old woman presented with sudden onset of headache. An admission computed tomographic (CT) scan revealed thick and diffuse subarachnoid hemorrhage involving primarily the carotid cistern and the proximal left sylvian fissure. A cerebral angiogram was initially interpreted as absent for aneurysm, but a follow-up angiogram performed 1 week later confirmed an enlarging aneurysm.

INTERVENTION:

A craniotomy with placement of an encircling clip graft around a blister-like aneurysm was performed.

CONCLUSION:

Although Sundt advocated the encircling clip graft for the blister-type aneurysm almost 40 years ago, use of an encircling clip graft in the treatment of blister-like aneurysms of the supraclinoid portion of the internal carotid artery seems to be reserved as a secondary or “rescue” measure in current practice. Neurosurgeons must familiarize themselves with this distinct entity (the blister-type aneurysm), recognize the possible risks associated with parallel clipping, and consider the use of an encircling clip graft as the primary treatment.

Outcome after microdiscectomy: results of a prospective single institutional study

BACKGROUND

Although lumbar microdiscectomy is one of the most frequently performed spinal procedures, little consensus exists in the literature regarding results. Whereas retrospective reports boast success rates as high as 98%, prospective studies are less sanguine with statistics in the 73-77% range.

METHODS

Prospective single-institution outcome study of all patients undergoing virgin unilateral single-level microdiscectomies by study surgeons November 1990 to March 1992. Outcome determined by patient-reported responses to mail questionnaire or phone interview by a disinterested party.

RESULTS

There were 374 patients operated on, average age 42.4 years with mean length of symptoms 9.4 months, and 31.5% were Workman's Compensation cases. Total complication rate was less than 4%, and follow-up was accomplished for 86% of the patients. Overall success rate was 74% using a strict combination of patient-reported pain relief, work status not affected, absence of narcotic use, and satisfaction with the procedure. Using a multivariate logistic regression analysis, only Workman's Compensation claim and length of symptoms (>6 months) were related to success, with a positive outcome in 86% of non-Compensation patients with brief symptoms contrasting with 29% in Compensation cases of greater than 6 months duration.

CONCLUSIONS

A prospective analysis of the frequency of success after microdiscectomy yields results lower than anticipated based on retrospective studies and finds success related to the non-anatomic factors of length of symptoms and Workman's Compensation claims.

Defining the limits of survivorship after very severe head injury

BACKGROUND

Reliable prediction of outcome after head injury is a daunting task. Although previous reports have highlighted the difficulties of determining outcome in the cohort of severe head injury Glasgow Coma Scale (GCS) score < or = 8), we wondered within the very severely injured population (GCS score 3-5) if a simple combination of clinical parameters may be predictive of poor outcome.

METHODS

All patients admitted to a Level 1 trauma center with a GCS score of 3 to 5 from 1986 to 1991 inclusive (380 patients) were retrospectively reviewed and outcome a minimum of 6 months after injury was determined by chart review or telephone.

RESULTS

Follow-up was accomplished in all but five patients (1.3%). Functional survival (nonvegetative) was correlated to admission GCS score, pupillary abnormalities, and age. As anticipated, overall functional survival was poor (12.5%), and even worse among those evidencing pupillary abnormalities (6.6%). Interestingly, there was an absence of survivors in the advanced age decades, with the oldest functional survivor of any GCS increasing in a stepwise fashion with increasing coma score. This translated into the oldest survivor of a GCS score of 3 being in their chronologic 30s, a score of 4 in their 40s, and a score of 5 in their 50s. Among patients older than these age decades, that is beyond this simple age/GCS cut-off (32.8% of cohort), there were no functional survivors (95% confidence interval 0, 2.4).

CONCLUSIONS

Within the population of very severely head injured patients (GCS score 3-5), the simple combination of age and admission GCS score appears to predict accurately non-functional outcome in almost one third of patients. If confirmed at other centers, this may have wide-ranging implications regarding counseling of families, utilization of resources, and the design of head injury studies.

Automated percutaneous discectomy

Automated percutaneous discectomy is the most popular technique for intradiscal therapy of lumbar disc disease, with over 80,000 procedures performed worldwide to date. Success rates range from 55% to 85%, and complications are very infrequent (less than one percent). Very careful patient selection seems critical for success.

Percutaneous laser discectomy

A variety of lasers have been employed to perform the percutaneous laser discectomy procedure, including Nd:YAG and the KTP/532. They all can effect a tract through the annulus and nucleus that is believed to reduce disc pressure under load. Although success rates following laser discectomy range between 70% and 80%, criteria for selecting patients are rather vague. Newer technology employing visualization within the disc vice fiberoptics is of questionable benefit.

Value of surgical intervention in the treatment of glioma

The benefit of cytoreductive surgery in the management of glioma remains speculative. We therefore reviewed all confirmed deaths in our Neuro-Oncology Program and examined various clinical factors related to survival. There were 63 patients (34 males/29 females), with an average age of 57.6 years. The pathology was glioblastoma in 44 and anaplastic astrocytoma in 19; median survival was 12 months. Forty patients underwent at least one craniotomy, following which 22.5% achieved a gross total resection, 23 had biopsy only. Only age and gross total resection of tumor as judged by postoperative MR (CT in 2 cases) correlated significantly with outcome. The subtotal craniotomy group and biopsy only cohort were indistinguishable (median survival 11 vs. 10 months, respectively). Although craniotomy associated with gross total resection results in enhanced survival (median 27 months), subtotal tumor excision offers little beyond a diagnosis. Therefore, careful and realistic preoperative assessment of glioma patients ought to be performed to determine optimal surgical management.

Laser discectomy. Comparison of systems

Percutaneous methods of lumbar disc removal have gained wide popularity since the introduction of the automated suction device. Newer methods to enter this field include the Nd:YAG and Ho:YAG lasers. To date, no experimental model exists to compare the efficacy of disc removal of these devices. An in vitro disc elastance (pressure/volume) model was designed that accurately reflects the mass of dry disc removed after any type of discectomy procedure. The experimental design consists of an infusion pump compressing a static column of air in line with the disc through a 12-gauge needle. Both mechanical and laser devices exhibited a reproducible treatment plateau, beyond which no disc removal was effected. Total energy, as opposed to power, was found to be the main determinant of the extent of disc removal during laser discectomy. Finally, in the experimental model of juvenile swine the automated suction device exhibited superior disc removal compared to the two lasers, but the clinical applicability of this is debatable. Disc space elastance offers a rapid and reproducible method to quantitate the extent of disc removal after intradiscal treatment methods and if employed in human cadaver spines may minimize the need for clinical trials to compare different devices and techniques.

Laser discectomy: a review

The percutaneous treatment of lumbar disc disease with laser energy has emerged recently as an alternative to open surgical or even mechanical percutaneous methods. Although numerous laser wavelengths have been employed in both the experimental and clinical settings, no consensus exists regarding selection of laser, treatment duration, or energy requirements. Inspection of the disc/water absorption spectrum combined with the limitations of the fiberoptic delivery systems argue for the use of lasers near 2.0 microns, such as the 2.1-microns Ho:YAG. Although recently developed in vitro models have allowed for laser system comparisons, most clinical work has been empiric, uncontrolled, and in very small series.

Intracranial cryosurgery in a canine model: a pilot study

Although virtually abandoned decades ago following the introduction of levodopa for the treatment of movement disorders, intracranial cryosurgery potentially offers a simple and accurate means of destroying deep-seated lesions when coupled with computed tomographic-stereotaxic placement techniques. We performed a pilot investigation of the size and histology of brain cryolesions in six dogs, using a 3-mm probe maintained at -160 degrees C for 6 minutes while simiultaneously monitoring the process by real-time ultrasound. Lesion diameter was 1.4 +/- 0.1 cm at less than or equal to 2 days but enlarged to 2.25 +/- 0.21 cm at 1 week, primarily at the expense of white matter. Ultrasound appearance of the lesion was characterized by a hyperechoic ice ball, the size of which consistently underestimated true size (determined by histology). By microscopy, the lesion was a hemorrhagic infarction that incited little surrounding edema and exhibited a sharp transitional zone. These data indicate that the cryosurgical probe can lesion significant volumes of brain in a reproducible and discrete fashion with minimal reaction to the surrounding tissue. Further work is required to clarify the observed "growth" of lesion size between days 2 and 7.

Lumbar surgery in the elderly

By virtue of modern neuroimaging, neurosurgeons are increasingly confronted by patients once deemed too old for lumbar corrective procedures. Management of these patients is problematic, as the literature is relatively mute in regard to results and complications within this elderly cohort. We, therefore, reviewed all surgical procedures for benign lumbar disease at two large metropolitan hospitals from January 1986 to June 1988 for patients greater than or equal to 70 years of age. There were 155 procedures performed on 143 patients (male:female, 48:95); the average age of the patients was 74.9 +/- 8.8 years; there were 32 cases of herniated disc, 29 cases of disc plus hypertrophic ligament/bone, and 94 cases of lateral recess/stenosis alone. Hospital stay averaged 7.5 +/- 3.5 days, and increasing age did not correlate with an extended admission. Major morbidity was low (6.9%), and there were no deaths. At follow-up, an average of 34.3 +/- 12.2 months postoperatively, 66.6% (56 of 84) of the patients reported no or minimal discomfort, whereas 15.4% (13 of 84) had not improved at all. Overall, 77.3% (65/84) were pleased with their procedure. These data represent the most comprehensive review in the literature of lumbar procedures in the elderly and indicate that these operations may be undertaken in this population with acceptable morbidity and a reasonable expectation of clinical improvement.

Percutaneous laser discectomy with the Ho:YAG laser

A prototype Ho:YAG (2.15 microns) laser operating at 2-J/pulse, 3 Hz through a 600-microns fiber was employed to perform laser discectomies at the L3-4 disc through an 18G needle in five juvenile pigs. No temperature elevations were recorded in the posterior longitudinal ligament at the disc level and all animals recovered fully with no adverse sequelae, even immediately upon awakening from anesthesia. Pathologic examination demonstrated a wide swath of coagulation necrosis confined to the disc space. The Ho:YAG laser, owing to its close approximation to the intense 2.0 microns absorption band of water, appears to be a viable candidate for clinical trials of laser discectomy.

Management of Athletic Injuries of the Cervical Spine and Spinal Cord

Injuries to the cervical spine among athletes present inherent difficulties, especially in advising for return to contact sports. Experience with the acute care of 63 patients who sustained cervical spine injuries while participating in organized sporting events is analyzed. Forty-five patients had permanent injury to the vertebral colum n and/or spinal cord, while 18 suffered only transient spinal cord symptoms. Football mishaps accounted for the highest number of injuries, followed by wrestling and gymnastics. Twelve patients had complete spinal cord injury, 14 patients had incomplete spinal cord injury, and 19 patients had injury to the vertebral column alone. The majority of the spinal cord lesions occurred at the C4 and C5 levels, while bony injuries of C4 through C6 predominated. Twenty-five patients required surgical stabilization, and 20 were treated with orthosis only. There was no instance of associated systemic injuries, and hospital complications were few. The mean time of hospitalization was 19.1 days for injured patients and 3.0 days for patients with transient symptoms. A classification was developed to assist in the management of these patients: Type 1 athletic injuries to the cervical spine are those that cause neurological injury; patients with Type 1 injuries are not allowed to participate in contact, competitive sporting events. Type 2 injuries consist of transient neurological deficits without radiological evidence of abnormalities; these injuries usually do not prohibit further participation in contact sports unless they become repetitive. Type 3 injuries are those that cause radiological abnormality alone; these represent a heterogeneous group. The athlete with fractures involving a significant structural portion of the vertebral column, ligament instability, spinal cord contusion, or congenital cervical stenosis, is advised not to return to contact sports. Other radiological abnormalities, such as compromise of the ligaments, congenital fusion, degenerative disease, and herniated cervical disc require individual consideration. The rationale for treatment and advising for participation in sports are discussed. We believe that this classification of sports injuries offers clinicians a framework within which to make rational judgments and recommendations in the management of athletes with cervical spine injuries.

Management of athletic injuries of the cervical spine and spinal cord

Injuries to the cervical spine among athletes present inherent difficulties, especially in advising for return to contact sports. Experience with the acute care of 63 patients who sustained cervical spine injuries while participating in organized sporting events is analyzed. Forty-five patients had permanent injury to the vertebral column and/or spinal cord, while 18 suffered only transient spinal cord symptoms. Football mishaps accounted for the highest number of injuries, followed by wrestling and gymnastics. Twelve patients had complete spinal cord injury, 14 patients had incomplete spinal cord injury, and 19 patients had injury to the vertebral column alone. The majority of the spinal cord lesions occurred at the C4 and C5 levels, while bony injuries of C4 through C6 predominated. Twenty-five patients required surgical stabilization, and 20 were treated with orthosis only. There was no instance of associated systemic injuries, and hospital complications were few. The mean time of hospitalization was 19.1 days for injured patients and 3.0 days for patients with transient symptoms. A classification was developed to assist in the management of these patients: Type 1 athletic injuries to the cervical spine are those that cause neurological injury; patients with Type 1 injuries are not allowed to participate in contact, competitive sporting events. Type 2 injuries consist of transient neurological deficits without radiological evidence of abnormalities; these injuries usually do not prohibit further participation in contact sports unless they become repetitive. Type 3 injuries are those that cause radiological abnormality alone; these represent a heterogeneous group.(ABSTRACT TRUNCATED AT 250 WORDS)

The Relationship between Survival and the Extent of the Resection in Patients with Supratentorial Malignant Gliomas

Current neurosurgical opinion favors the radical surgical removal of supratentorial gliomas, when feasible, in the belief that this optimizes patient survival. Although bolstered by the results of some early investigators, the efficacy of this approach remains debatable. Therefore, we undertook a review of the English language literature of the past 30 years for a series of surgically treated malignant gliomas. Twenty reports comprising 5691 patients were identified. Only 4 found the extent of the surgical resection related to survival. In 2 of these, it followed age, histological findings, and performance status in importance. The 2 other studies did not rank the prognostic variables at all. On closer inspection, however, there does appear to be a subgroup of young patients with favorable histological findings and good performance status for whom surgery is beneficial. Future reporting of surgical results of patients with gliomas will require stratification by the known prognostic variables of age. histological findings, and performance status to characterize better this subgroup for whom surgery is beneficial.