The origin of brain metastases in patients with an undiagnosed primary tumour

BACKGROUND

In patients presenting brain metastases as the first manifestation of a previously undiagnosed primary tumour (UDP) histopathological confirmation of the diagnosis can be obtained by either direct surgical sampling of the brain lesion or paraclinical search for an accessible primary tumour. The sequence of the diagnostic work-up and the timing of an eventual neurosurgical intervention are a matter of debate and are mainly influenced by the distribution of primary tumours in UDP patients. The aim of this study was to verify the hypothesis that the distribution of primary tumours differs between UDP patients and the rest of the patients with brain metastases (DP), and to propose a diagnostic work-up specifically tailored to the UDP population.

METHODS

Retrospective study on 342 patients admitted to the Lausanne University hospital between 1983 and 1998 with the diagnosis of cerebral metastases.

FINDINGS

UDP patients represented 36% of the whole group. Primary tumour location was significantly different between the two groups (p=0.001). Although the lung was the most frequent primary tumour location in both groups (UDP: 60%, DP: 43%), in UDP 14% only of the primaries were found outside of the lung and as much as 26% remained unknown despite thorough investigations.

CONCLUSIONS

Our study confirmed the hypothesis that the relative frequency of primary tumours differs between DP and UDP patients. This difference therefore mandates a diagnostic strategy specifically tailored for UDP patients: if a radiological lung investigation clearly remains the best initial step in the work-up of these patients, extensive paraclinical investigations without a clear clinical suspicion should probably not be undertaken if this first survey fails to disclose the primary tumour as only 14% of the patients will actually benefit from it. In this situation, a neurosurgical procedure should probably be considered the most appropriate next step to be taken in order to provide a definitive diagnosis without unnecessary delays.

[Spinal tumors: clinical aspects, classification and surgical treatment]

Spinal tumors are classified in intradural and extradural tumors. Most extradural spinal tumors are metastasis. The other spinal tumors are rare and mostly benign. Only about 5% of tumors of the nervous system are spinal tumors. Their symptomatology is often insidious and the diagnosis can be difficult. Magnetic resonance imaging has revolutionized their diagnosis. The lesions within the spinal cord can now be directly visualized. The treatment of these tumors mostly require surgery. It has been proven that surgical results are better if these tumors are operated as soon as neurological symptoms have appeared. In our series of 39 operated intradural tumors we noted a functional improvement in 46.5% of the cases, a stabilisation in 43.5% and a deterioration in 10%.

Current strategies in the management of spinal metastatic disease

The treatment of metastatic spinal cord compression is complex. The three treatment modalities that are currently applied (in a histologically non-specific manner) are surgery, radiotherapy and the administration of steroids. The development of new spinal instrumentations and surgical approaches considerably changed the extent of therapeutic options in this field. These new surgical techniques have made it possible to resect these tumours totally, with subsequent vertebral reconstruction and spinal stabilization. In this respect, it is important to clearly identify those patients who can benefit from such an extensive surgery. We present our management algorithm to help select patients for surgery and at the same time identifying those for whom primary non-surgical therapy would be indicated. The retrospective review of surgically treated patients in our department in the last four years reveals a meagre application of conventional guidelines for the selection of the appropriate operative approach in the surgical management of these patients. The reasons for this discrepancy are discussed.

Spontaneous bilateral subdural haematomas in the posterior cranial fossa revealed by MRI

A 52-year-old woman treated for acute myeloproliferative disease developed progressive stupor. CT showed obstructive hydrocephalus resulting from unexplained mass effect on the fourth ventricle. MRI revealed bilateral extra-axial collections in the posterior cranial fossa, giving high signal on T1- and T2-weighted images, suggesting subacute subdural haematomas. Subdural haematomas can be suspected on CT when there is unexplained mass effect. MRI may be essential to confirm the diagnosis and plan appropriate treatment.

[Role of surgical treatment of low back pain and lumbo-sciatica]

Low back pain alone without any sciatica is not an appropriate indication for lumbar disc surgery. The only exception might be a clinically and radiologically proven segmental instability. However a conservative multidisciplinary treatment should precede surgery. Good and excellent results of lumbar disc surgery are achieved in 80-90% of cases. The appropriate surgical indication and the postoperative reeducation are of utmost importance for good results. The patients history, neurological examination, neuroradiological imaging and failed conservative treatment modalities are key elements to define appropriate surgical candidates. Microdisectomy remains the "gold standard" for surgical treatment of lumbar disc disease assuring a better quality of life at long term follow up.

Surgical treatment of lumbar spinal stenosis. Five-year follow-up

We carried out a retrospective review of 155 patients with lumbar spinal stenosis who had been treated surgically and followed up regularly: 77 were evaluated at a mean of 6.5 years (5 to 8) after surgery by two independent observers. The outcome was assessed using the scoring system of Roland and Morris, and the rating system of Prolo, Oklund and Butcher. Instability was determined according to the criteria described by White and Panjabi. A significant decrease in low back pain and disability was seen. An excellent or good outcome was noted in 79% of patients; 9% showed secondary radiological instability. Surgical decompression is a safe and efficient procedure. In the absence of preoperative radiological evidence of instability, fusion is not required.

Surgical treatment of lumbar spinal stenosis

We carried out a retrospective review of 155 patients with lumbar spinal stenosis who had been treated surgically and followed up regularly: 77 were evaluated at a mean of 6.5 years (5 to 8) after surgery by two independent observers. The outcome was assessed using the scoring system of Roland and Morris, and the rating system of Prolo, Oklund and Butcher. Instability was determined according to the criteria described by White and Panjabi.

A significant decrease in low back pain and disability was seen. An excellent or good outcome was noted in 79% of patients; 9% showed secondary radiological instability.

Surgical decompression is a safe and efficient procedure. In the absence of preoperative radiological evidence of instability, fusion is not required.

Appropriateness of surgery for sciatica: reliability of guidelines from expert panels

STUDY DESIGN

Reliability study of guidelines development.

OBJECTIVE

To compare criteria for low back surgery between two expert panels.

BACKGROUND

Reliability of expert panels for determining appropriateness of indications for surgical procedures has heretofore received little attention.

METHODS

Two multidisciplinary expert panels of similar composition were convened, in the United States and in Switzerland, to evaluate the appropriateness of 720 distinct clinical scenarios involving sciatica. Each indication was assigned to a category of appropriate, uncertain, and inappropriate. The appropriateness of the 720 theoretical scenarios were compared between the two panels, and both sets of criteria were applied to two series of actual cases.

RESULTS

Seventy-nine percent (n = 566) of the 720 theoretical indications were assigned to identical categories of appropriateness by both panels (kappa = 0.63; P < 0.001). Only 2 of the 720 scenarios elicited frank disagreement. The percentage of the 720 indications that were considered appropriate differed between the two panels (U.S.: 3%; Swiss: 11%, P < 0.001), as did the percentage of intrapanel agreement for indications (U.S.: 51%, Swiss: 64%, P < 0.001). When the same theoretical scenarios were matched with two series of actual cases (n = 181 and 149) agreement was moderate (kappa = 0.46) to fair (kappa = 0.30).

CONCLUSION

There was substantial agreement on the appropriateness of surgery for theoretical cases of sciatica between independent expert panels from two countries. A better understanding of discordant ratings, especially for actual cases, should precede attempts at transposing recommendations emanating from a panel in one country to another.

Cytochrome P-450 activities in human and rat brain microsomes

The role of cytochrome P450 in the metabolism of dextromethorphan, amitriptyline, midazolam, S-mephenytoin, citalopram, fluoxetine and sertraline was investigated in rat and human brain microsomes. Depending on the parameters, the limit of quantification using gas chromatography-mass spectrometry methods was between 1.6 and 20 pmol per incubation, which generally contained 1500 microg protein. Amitriptyline was shown to be demethylated to nortriptyline by both rat and human microsomes. Inhibition studies using ketoconazole, furafylline, sulfaphenazole, omeprazole and quinidine suggested that CYP3A4 is the isoform responsible for this reaction whereas CYP1A2, CYP2C9, CYP2C19 and CYP2D6 do not seem to be involved. This result was confirmed by using a monoclonal antibody against CYP3A4. Dextromethorphan was metabolized to dextrorphan in rat brain microsomes and was inhibited by quinidine and by a polyclonal antibody against CYP2D6. Only the addition of exogenous reductase allowed the measurement of this activity in human brain microsomes. Metabolites of the other substrates could not be detected, possibly due to an insufficiently sensitive method. It is concluded that cytochrome P450 activity in the brain is very low, but that psychotropic drugs could undergo a local cerebral metabolism which could have pharmacological and/or toxicological consequences.

Statistical approaches in the development of clinical practice guidelines from expert panels: the case of laminectomy in sciatica patients

BACKGROUND

Variation in expert opinion and lack of a systematic methodology hinder the development of reliable clinical practice guidelines. However standardized protocols have been defined to quantify, combine, and summarize expert judgments. In addition, statistical methods may help to outline guidelines based on simplified models of these judgments.

METHODS

To test this hypothesis, stepwise logistic regression (SLR) and classification tree pruning (CTP) were used to predict the results of two expert panels (USA 1992 and Switzerland 1995) on laminectomy in sciatica conditions. Both panels, using the RAND-UCLA explicit method, assessed whether the procedure would be inappropriate or of potential use in 720 case scenarios combining 7 relevant factors.

RESULTS

Laminectomy was rated as inappropriate in 60% and 70% of the scenarios by the US and Swiss panels, respectively. Either statistical method, in both panels, based its simplest model on the same 4 factors, as follows: imaging test results; disability; neurological findings; and conservative treatment trials (in decreasing order); the influence of 2 other factors, duration of pain and nerve root irritation, were only marginal. The correct classification rates of the models were 89% and 93% for SLR and 93% and 85% for CTP. Adopting the CTP US algorithm as a guideline would lead to consider performing laminectomy only in patients with imaging evidence of hernia, relatively severe disability, reflex abnormalities, and previous nonsurgical treatment. Adherence to the corresponding CTP Swiss algorithm would result in less restrictive conditions.

CONCLUSION

The statistical techniques proved as useful instruments to structure and simplify appropriateness criteria developed by expert panels and to outline parsimonious decision models for clinical practice.

Can the decision to operate be judged retrospectively? A study of medical records

OBJECTIVE

To examine the precision and completeness of information in medical records for evaluating the appropriateness of operative indications for lumbar disc surgery.

DESIGN

Retrospective review of records.

SETTING

University department of neurosurgery, Switzerland.

SUBJECT

100 patients.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Proportion of pre-defined, detailed appropriateness criteria present in the records. Proportion of cases that could unequivocally be classified as to the appropriateness of the indication for operation.

RESULTS

The criteria were present and precise for 52 of the items (range 9-90); present but imprecise for 38 of the items, and absent for 10. Because of this imprecision, the appropriateness of only 7 of the operative indications could be unequivocally assessed retrospectively.

CONCLUSION

Medical records are of limited use in assessing the appropriate management of care. The process of care should therefore be evaluated prospectively.

Inhibition of epidural fibrosis with ADCON-L: effect on clinical outcome one year following re-operation for recurrent lumbar radiculopathy

In a prospective multicenter study, 20 patients underwent re-operation for recurrent radiculopathy after lumbo-sacral discectomy, and were treated with ADCON-L (Adhesion Control in a Barrier Gel) to inhibit epidural fibrosis following secondary surgery. Outcomes after re-operation were assessed at six and 12 months using: Visual Analog Scales to measure radicular and back pain, straight leg raising exams, and self-assessment of activity-related radicular pain. Each parameter was compared to baseline values, obtained immediately prior to the re-operation. The long term clinical results at 12 months after re-operation (summarized below) demonstrate a significant improvement of all clinical parameters, and correlated with the results seen at six months. Radicular pain, measured when most severe, was reduced from an average pre-operative score of 8.1-3.7 (p < 0.005). The straight leg raising angle increased from an average pre-operative value of 41 degrees-67 degrees (p < 0.005). Activity-related pain mean score was 4.6, vs. 17.0 pre-operatively (p < 0.005). Low back pain, measured when most severe, was reduced from an average pre-operative score of 6.1 to 3.1 (p < 0.012). These clinical findings compare very favorably with data reported in the literature. There were no adverse events or complications related to the use of ADCON-L.

The assessment of appropriate indications for laminectomy

We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques.

The assessment of appropriate indications for laminectomy

We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases.

We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate.

The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques.

Long-term follow up of patients surgically treated by the far-lateral approach for foraminal and extraforaminal lumbar disc herniations

OBJECT

This study was undertaken to evaluate the long-term benefit in 202 patients who were surgically treated via a microsurgical far-lateral approach for foraminal or extraforaminal lumbar disc herniations.

METHODS

All patients underwent surgery at the authors' institute since 1987 and represented 6.5% of all lumbar spinal disc surgeries. There were 67 women and 135 men who ranged in age from 19 to 78 years (mean age 58 years). All patients had unilateral leg pain due to lumbar disc herniations into or lateral to the lateral interpedicular compartment. One patient underwent surgery at the L1-2 level, nine at L2-3, 48 at L3-4, 86 at L4-5, and 58 at the L5-S1 level. The mean follow-up period was 50 months (range 12-120 months). Outcome was defined as excellent (no pain), good (some back pain), fair (moderate radiculopathy), and poor (unchanged or worse) based on Macnab classification. Overall, excellent and good results were achieved in 62 (31%) and 85 (42%) patients, respectively, and fair and poor results in 40 (20%) and 15 (7%) patients, respectively. Of 11 recurrent disc herniations, four presented in an extreme-lateral position, five in a paramedian location, and two on the contralateral side. There were three minor complications related to surgery, seven general complications, and no case of spinal instability.

CONCLUSIONS

The far-lateral approach is a safe, effective procedure that avoids the risk of secondary spinal instability.

[The effect of position on intracranial pressure]

The question as to whether the head and trunk of neurosurgery patients should be elevated remains controversial. This question is particularly important when intracranial hypertension is present. Head up position may have beneficial effects on intracranial pressure (ICP) via changes in mean arterial pressure (MAP), airway pressure, central venous pressure and cerebro spinal fluid displacement. However, in some circumstances, head up position may decrease MAP which in turn will result in a paradoxical rise in ICP through autoregulation mechanisms. Therefore, the degree of head elevation has to be titrated by evaluating the most adequate cerebral perfusion pressure (CPP) for each patient by means of transcranial Doppler or measurement of jugular venous blood oxygen saturation. Head elevation above 30 degrees should be avoided in all cases. In most patients with intracranial hypertension, head and trunk elevation up to 30 degrees is useful in helping to decrease ICP, providing that a safe CPP of at least 70 mmHg or even 80 mmHg is maintained. Patients in poor haemodynamic conditions are best nursed flat. CPP is thus the most important factor in assessment and monitoring when considering head elevation in patients with increased ICP.

Clinical assessment of a novel antiadhesion barrier gel: prospective, randomized, multicenter, clinical trial of ADCON-L to inhibit postoperative peridural fibrosis and related symptoms after lumbar discectomy

A prospective, multicenter, randomized, double-blind, controlled study of ADCON-L Anti-Adhesion Barrier Gel (a medical device by Gliatech Inc, Cleveland, OH) was conducted in 298 patients undergoing first-time lumbar discectomy to evaluate the safety and effectiveness of ADCON-L in preventing postoperative peridural fibrosis and in improving patient clinical outcome. After lumbar discectomy, patients were randomized to receive either ADCON-L gel or nothing (control group) at the conclusion of the surgical procedure. Six months after surgery, peridural scar was evaluated by magnetic resonance imaging, and postoperative pain and straight-leg-raise angle were assessed. No statistically significant differences between the ADCON-L and control groups were observed in terms of adverse events or wound healing characteristics. ADCON-L gel was shown to be safe and to significantly inhibit peridural scar compared with the control group (P = 0.002). That peridural scarring was reduced with ADCON-L gel was further supported by direct visualization of scar tissue at reoperation in both groups. ADCON-L-treated patients had better clinical outcomes than did control patients. The incidence of activity-related pain was significantly reduced (P = 0.013), straight-leg-raise examination scores were significantly improved (P = 0.024 on the operative side and P = 0.015 on the nonoperative side), and ADCON-L reduced low back pain when it was most severe (P = 0.047) and at the end of the day (P = 0.044).

Cervical amyloidoma of C2. Case report and review of the literature

STUDY DESIGN

Second published report of a patient with amyloidoma of the upper cervical spine.

OBJECTIVES

To describe a patient with rare radiculopathy to alert other physicians to consider amyloid tumor as a differential diagnosis of locally destructive spine lesions.

SUMMARY OF BACKGROUND DATA

Localized amyloid tumor of the bone is a rare disease. Only seven cases of spine involvement have been reported. Appropriate tissue sampling is required to establish the diagnosis. Histopathologic examination shows pathognomonic apple-green birefringence under polarized light. When bone is involved with amyloid, it is most commonly associated with multiple myeloma or other plasma cell-dyscrasias.

METHOD

This case was described, and pertinent literature was reviewed.

RESULTS

The patient showed persistent neurologic improvement after transoral complete tumor removal, followed by a secondary posterior stabilization procedure using transarticular C1-C2 screws.

CONCLUSIONS

Amyloidomas are benign lesions with no associated documented risk for the development of plasmocytoma-related diseases. The clinical and radiographic manifestations of this lesion are nonspecific. A cure is possible with complete resection of the tumor and no adjuvant management procedures.

Unusual complications at iliac crest bone graft donor site: experience with two cases

OBJECTIVE AND IMPORTANCE

Two cases of fracture of the iliac crest after graft harvesting are presented. Only six such cases have been reported in the literature, although more than 100,000 such procedures are performed each year in the United States alone. This complication adds to the morbidity of the procedure for which the graft is taken. Its avoidance by an appropriate harvesting technique will reduce patient disability and shorten hospital stay.

CLINICAL PRESENTATION

A 56-year-old man who worked as a mechanic underwent anterior cervical discectomies and fusion at C5-C6 and C6-C7 for spondylotic radiculopathies. Another patient, a 48-year-old man, required mandibular reconstruction for squamous cell carcinoma. Both grafts were harvested from the iliac crest using osteotomies. On the 9th and 3rd postoperative days, respectively, each patient developed groin pain while walking, associated with marked tenderness over the graft donor sites. X-rays showed fractured iliac crests.

INTERVENTION

Apart from bed rest for pain, no specific treatment was required.

CONCLUSION

The use of the osteotome weakens the iliac crest, leading to stress fractures caused by the pulling action of the attached muscles. To prevent this from happening, we recommend the use of the oscillating saw, leaving a 3-cm spike of iliac crest anteriorly. Nevertheless, this complication has a good long-term outcome.