What is the Pressure in Chronic Subdural Hematomas? A Prospective, Population-Based Study

Are there characteristic indicators for increased pressure in chronic subdural hematoma?

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical disorders. However, no study has yet documented biomarkers indicating increased CSDH pressure. This study aimed to explore such indicators. A total of 50 patients underwent measurement for CSDH pressure during burr-hole irrigation. The mean hematoma pressure was 16.8 ± 7.6 cmH2O with no significant difference between new-onset and recurrent CSDHs. In 12 patients with a CSDH pressure ≥25 cmH2O, further analyses were carried out. Eight of them had bilateral CSDHs. All six patients with a CSDH pressure ≥28 cmH2O suffered headaches before surgery. Two out of three patients with a CSDH pressure ≥29 cmH2O felt nauseous. In statistical analyses, headache was positively correlated with a high CSDH pressure, whereas age and hematoma thickness were negatively correlated with it. Patients' sex, initial Glasgow coma scale score, motor weakness, midline shift on computed tomography scans, and administration of anticoagulants/antiplatelet agents, showed no significant correlation. When patients with bilateral CSDHs are not older adults and suffering headaches, an increased CSDH pressure should be assumed. For such patients, a prompt hematoma evacuation is indicated.

Development and validation of a recurrent prediction model for patients with unilateral chronic subdural hematoma without hematoma volumetric analysis

OBJECTIVE

Approximately 10 % of patients with chronic subdural hematoma (CSDH) undergo reoperation after initial surgery. This study aimed to develop a predictive model for the recurrence of unilateral CSDH at initial surgery without hematoma volumetric analysis.

METHODS

This single-center retrospective cohort study evaluated pre- and postoperative computed tomography (CT) images of patients with unilateral CSDH. The pre- and postoperative midline shift (MLS), residual hematoma thickness, and subdural cavity thickness (SCT) were measured. CT images were classified based on the internal architecture of the hematoma (homogenous, laminar, trabecular, separated, and gradation subtypes).

RESULTS

Total 231 patients with unilateral CSDH underwent burr hole craniostomy. After receiver operating characteristic analysis, preoperative MLS and postoperative SCT showed better areas under the curve (AUCs) (0.684 and 0.756, respectively). According to the CT classification of preoperative hematomas, the recurrence rate was significantly higher in the separated/gradation group (18/97, 18.6 %) than in the homogenous/laminar/trabecular group (10/134, 7.5 %). Four-point score was derived from the multivariate model using the preoperative MLS, postoperative SCT, and CT classification. The AUC of this model was 0.796, and the recurrence rates at 0-4 points were 1.7 %, 3.2 %, 13.3 %, 25.0 %, and 35.7 %, respectively.

CONCLUSION

Pre- and postoperative CT findings without hematoma volumetric analysis may predict CSDH recurrence.

Change in Hematoma Size after Dexamethasone Therapy in Chronic Subdural Hematoma Subtypes: A Prospective Study in Symptomatic Patients

The main treatment strategy for chronic subdural hematoma is surgical intervention. When a conservative pharmacological approach is considered in symptomatic patients, mainly dexamethasone therapy is applied. Recent trials revealed dexamethasone therapy to be an ineffective treatment in symptomatic patients with chronic subdural hematoma. Whether the efficacy of dexamethasone therapy differs in radiological hematoma subtypes is unknown. The aim of this substudy was to identify which hematoma subtype might be favorable for dexamethasone therapy. As part of a randomized controlled trial, symptomatic chronic subdural hematoma patients received 19-days dexamethasone therapy. The primary outcome measure was the change in hematoma size as measured on follow-up computed tomography (CT) after 2 weeks of dexamethasone in six hematoma (architectural and density) subtypes: homogeneous total, laminar, separated and trabecular architecture types, and hematoma without hyperdense components (homogeneous hypodense, isodense) and with hyperdense components (homogeneous hyperdense, mixed density). We analyzed hematoma thickness, midline shift, and volume using multi-variable linear regression adjusting for age, sex and baseline value of the specific radiological parameter. From September 2016 until February 2021, 85 patients were included with a total of 114 chronic subdural hematoma. The mean age was 76 years and 25% were women. Larger decrease in hematoma thickness and midline shift was revealed in hematoma without hyperdense components compared with hematoma with hyperdense components (adjusted [adj.] b -2.2 mm, 95% confidence interval [CI] -4.1 to -0.3 and adj. b -1.3 mm, 95% CI -2.7 to 0.0 respectively). Additional surgery was performed in 57% of patients with the highest observed rate (81%) in separated hematoma. Largest hematoma reduction and better clinical improvement was observed in chronic subdural hematoma without hyperdense components after dexamethasone therapy. Evaluation of these parameters can be part of an individualized treatment strategy.

A Single-Center Analysis of Sex Differences in Patients With Chronic Subdural Hematoma in China

Background

Given the men's predominance in the prevalence of chronic subdural hematoma (CSDH), we investigated the relationship between sex differences and clinical features of CSDH.

Methods

We retrieved a large collection of clinical factors from CSDH patients between August 2011 and May 2019, and analyzed the differences and similarities in the clinical data and outcomes between men and women.

Results

In total 1,307 CSDH patients were enrolled in this study. When we did not account for age, a greater proportion of women relative to men manifested diabetes (p = 0.001) and cardiac disease (p = 0.035) prior to the onset of CSDH. Regarding recovery outcome and recurrence rate, we observed no significant differences between men and women. The sole difference between women and men after surgery was that women experienced more complications than men (p = 0.044), and both length of hospital stay (p < 0.001, B = 0.159, Exp [B] = 1.172, 95% CI = 1.078–1.274) and the presence of cardiac disease (p = 0.002, B = 2.063, Exp [B] = 7.867, 95% CI = 2.167–28.550) were identified as independent risk factors. After accounting for age, women with CSDH exhibited more frequent disorders of consciousness at admission than men in group of ≤ 40-year-old patients (p = 0.018), while proportion of women with diabetes was higher than that of men in 41–79 year-old group (p < 0.001). However, women after surgery experienced more complications (p = 0.047), longer length of hospital stays (p = 0.005), and higher mortality at discharge (p = 0.035) than men in middle-aged group. Finally, length of hospital stay (p < 0.001, B = 0.186, Exp [B] = 1.205, 95% CI = 1.091–1.331) and cardiac disease (p = 0.017, B = 2.040, Exp [B] = 7.693, 95% CI = 1.430–41.372) impacted occurrence of complications in women 41–79-year-old, while duration of drainage catheter use (p < 0.001, B = 1.132, beta = 0.280) and complications (p < 0.001, B = 5.615, beta = 0.366) were identified as independent risk factors for length of hospital stay in the same group of women.

Conclusions

Although sex differences did not constitute a crucial factor in all the CSDH patients, we still need to pay closer attention to disparities between men and women with respect to complications, length of hospital stay, and mortality at discharge in the various age groups (particularly with respect to 41–79 year-old women patients), to provide satisfactory management and treatment of CSDH patients.

Lateral Ventricular Volume Asymmetry and Optic Nerve Sheath Diameter Predict Intracranial Pressure in Traumatic Brain Injury Patients

Background

Various noninvasive methods of intracranial pressure (ICP) measurement have been proposed. Each has unique advantages and limitations. This study was aimed at investigating the relationships between lateral ventricular asymmetry on admission computed tomography, optic nerve sheath diameter (ONSD), and ICP in traumatic brain injury (TBI) patients.

Methods

A prospective observational study was conducted in the patients admitted to our department between October 2018 and October 2020. 20 patients with moderate-severe TBI with a Glasgow Coma Scale of 3-12 were enrolled. Lateral ventricle volume (LVV) value measurements were conducted using ITK-SNAP software. The lateral ventricular volume ratio (LVR) was quantified by dividing the larger LVV by the smaller.

Results

ONSD and LVR had a good correlation with ICP. Admission LVR of >1.735 was shown to have a sensitivity of 90.9% and a specificity of 88.9% for prediction of ICP increase (AUC = 0.879; standard error = 0.091; 95% CI = 0.701 to 1.0; significance level p < 0.004). Admission ONSD of >5.55 mm was shown to have a sensitivity of 81.8% and a specificity of 88.9% for prediction of ICP increase (AUC = 0.919; standard error = 0.062; 95% CI = 0.798 to 1.0; significance level p < 0.002). Combining the ONSD and LVR, the sensitivity could be improved to 90.9% in parallel test, and the specificity could be improved to 100% in serial test.

Conclusion

ONSD and LVR measurements can diagnose elevated ICP in traumatic brain injury patients. ONSD combining with LVR may further improve the diagnostic evaluation.

A nomogram for estimating intracranial pressure using acute subdural hematoma thickness and midline shift

Although criteria for surgical treatment of acute subdural hematoma (SDH) have been proposed, interaction exists between SDH, midline shift (MLS), and intracranial pressure (ICP). Based on our half sphere finite-element model (FEM) of the supratentorial brain parenchyma, tools for ICP estimation using SDH thickness (SDHx) and MLS were developed. We performed 60 single load step, structural static analyses, simulating a left-sided SDH compressing the cerebral hemispheres. The Young's modulus was taken as 10,000 Pa. The ICP loads ranged from 10 to 80 mmHg with Poisson's ratios between 0.25 and 0.49. The SDHx and the MLS results were stored in a lookup table. An ICP estimation equation was derived from these data and then was converted into a nomogram. Numerical convergence was achieved in 49 model analyses. Their SDHx ranged from 0.79 to 28.3 mm, and the MLS ranged from 1.5 to 16.9 mm. The estimation formula was log(ICP) = 0.614-0.520 log(SDHx) + 1.584 log(MLS). Good correlations were observed between invasive ICP measurements and those estimated from preoperative SDHx and MLS data on images using our model. These tools can be used to estimate ICP noninvasively, providing additional information for selecting the treatment strategy in patients with SDH.

Arachnoid Plasty to Prevent and Reduce Chronic Subdural Hematoma after Clipping Surgery for Unruptured Intracranial Aneurysm : A Meta-Analysis

Objective

Recent studies have reported that arachnoid plasty (ARP) using gelatin sponges with fibrin glue reduced the occurrence of chronic subdural hematoma (CSDH) following clipping surgery for unruptured intracranial aneurysm (UIA). This meta-analysis was conducted to collate further evidence for the efficacy of ARP in preventing postoperative CSDH.

Methods

Data of patients who underwent clipping surgery were extracted from PubMed, EMBASE, and Cochrane Central Register of Controlled Trials by two independent reviewers. A random effects model was used to investigate the efficacy of ARP by using odd ratios (ORs) and 95% confidence intervals (CIs). A meta-regression analysis for male sex was additionally preformed.

Results

Data from six studies with 1715 patients were consecutively included. Meta-analysis revealed that ARP was significantly associated with lower rates of CSDH development after surgical clipping for UIA (ARP group vs. control group : 3.2% vs. 7.2%; OR, 0.40; 95% CI, 0.18–0.93; I² =44.3%; p=0.110). Meta-regression analysis did not highlight any modifying effect of the male sex on postoperative CSDH development (p=0.951).

Conclusion

This meta-analysis indicated that ARP reduced the incidence rates of CSDH following clipping surgery for UIA. If feasible, ARP would be implemented as an additional surgical technique to prevent postoperative CSDH development during surgical clipping of UIA.

Diagnostic value of lateral ventricle ratio: a retrospective case-control study of 112 acute subdural hematomas after non-severe traumatic brain injury

PRIMARY OBJECTIVE

To evaluate correlation between the lateral ventricle ratio (LVR) and the risk of conservative treatment failure (CTF) among patients with acute subdural hematoma (ASDH) after non-severe traumatic brain injury (TBI), we retrieved from the hospital database and performed a retrospective analysis of 1339 cases with TBI treated during the 2008-2016 period.

METHODS AND PROCEDURES

112 patients with ASDH, GCS≥ 9 and initial conservative treatment were enrolled. They were divided according to the final treatment method applied (surgical or conservative). Clinical and radiological data was evaluated. We used ROC curve analysis and multivariate logistic regression model to identify risk factors of CTF.

MAIN OUTCOMES AND RESULTS

LVR higher than 1.48 calculated on admission CT scans was the strongest predictor of CTF, with sensitivity of 78.9% and specificity of 93.5% (AUC: 0.774-0.994). LVR, prolonged prothrombin time and coexisting traumatic subarachnoid hemorrhage were independent risk factors.

CONCLUSIONS

Despite limitations, study results support the view that patients after non-severe TBI with ASDH and with lateral ventricle asymmetry, defined as LVR> 1.48, require surgical treatment. LVR seems to be indirect, but still the closest method to quantify intracranial compliance. Thus, in the selected group of patients without clinical symptoms of critically diminished compensatory reserve, LVR could indicate those who need a surgical decompression.

The depth of catheter in chronic subdural haematoma: does it matter?

Objective: To investigate the appropriate depth of drainage catheter in the patients with chronic subdural haematoma (CSDH). Methods: We retrospectively analysed the data of 190 patients with CSDH undergoing single parietal burr-hole evacuation and drainage. Results: According to the depth of catheter (DC), 190 patients were divided into three groups: shallow group (DC <4.3 cm), middle group (DC 4.3 ~ 5.4 cm) and deep group (DC > 5.4 cm). During postdischarge 6 months, two, six and nine patients had recurrences in shallow, middle and deep groups, respectively. The recurrence rate in shallow or middle group was significantly lower than that in deep group. No significant difference in preoperative haematoma volume (PHV) was observed in three groups. While the residual subdural space (RSS) in shallow group was significantly smaller than those in the other two groups. The duration of drainage in shallow, middle and deep groups increased successively, and the differences were statistically significant. The total drainage volume (TDV) in shallow group showed no significant difference when compared with the other two groups. Conclusion: The depth of catheter may affect the outcome of CSDH. Inserting drainage catheter shallowly might be a preferred choice in patients with CSDH undergoing burr-hole evacuation and drainage.

Headache in patients with chronic subdural hematoma: analysis in 1080 patients

Headache is a major symptom in chronic subdural hematoma (CSDH) patients. However, some CSDH patients do not complain headache although the hematoma is thick with definite midline shift. This clinical study was performed to identify the mechanism of headache in CSDH patients. We compiled clinical data of 1080 surgically treated CSDH patients (711 males and 369 females), and in 54 cases, the pressure of hematoma was measured during burr hole surgery using a glass-stick manometer. Headache was recognized in 22.6% of patients, while nausea or vomit suggesting increased intracranial pressure was detected in only 3.0%. Ophthalmological examination was performed in 238 patients, and papilledema was identified in only one patient (0.4%). The mean age of patients with headache (59.8 ± 16.9 years) was significantly younger than that of those without (75.7 ± 11.2 years) (P < 0.01). In 54 cases, the mean hematoma pressure was not significantly different between patients with (17.1 ± 6.2 mmH₂O) and without (18.4 ± 7.2 mmH₂O) headache (P > 0.10). Hematoma thickness was significantly greater in patients without headache (P < 0.01), but the ratio of midline shift to hematoma thickness was significantly greater in patients with headache (P < 0.01). In our results, the status of increased intracranial pressure was rare in CSDH patients, and high hematoma pressure was not a cause of headache. Midline shift was the most influenced factor for headache in our study, and based on the results, the authors consider that the potential cause of headache in CSDH might be stretching or twisting of the pain-sensitive meninges and meningeal arteries or veins.

Subdural effusion protects the aging brain from harmful ventriculomegaly

The human brain loses its volume and its function during aging. The solid part of the brain within the intracranial space, the brain parenchyma, decreases in volume with age; while the cerebrospinal fluid (CSF) volume increases. With progressive loss of brain parenchymal volume (BPV), CSF may shift from cerebral ventricles to the subdural space, forming subdural effusion (SDE), whose role in the brain aging process remains unclear. We hypothesize that damages associated with ventriculomegaly can be lessened after formation of SDE. As the BPV decreases, the enlarged ventricular surface area causes dysfunction of its lining ependymal cells, followed by damages to the periventricular tissue. The periventricular nerve fibers are stretched by the enlarged ventricles. We hypothesize that after the formation of SDE, ventriculomegaly can be stopped or even reversed. By allowing the atrophic brain to reside in a smaller fraction of the intracranial volume, damages associated with ventriculomegaly can be alleviated. If our hypothesis is correct, physicians should continue to maintain a conservative approach for uncomplicated SDE. For focal or global brain parenchymal loss caused by various pathologies, intracranial spacers can be employed to simulate the effect of SDE to protect the brain. For treatment of idiopathic normal pressure hydrocephalus, aggressive ventricular size reduction should be pursued. Finally, the protective effects of SDE have its limits. Extremely enlarged subdural volume can cause acute or chronic subdural hematoma, further damaging the brain.

Surgical treatment for spinal dural arteriovenous fistulas: Outcome, complications and prognostic factors

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas (SDAVFs) are rare, acquired pathology and they inevitably lead to severe disability if untreated. The aim of this study is to present the outcome and complications, and to find factors that may affect the outcome after surgical treatment.

METHODS

Seventeen consecutive patients (men - 14, women - 3, age: 41-79) were retrospectively analyzed. The patients presented with paraparesis (88%), bladder symptoms (71%) and/or sensory disturbances (65%). The fistula was found in the upper thoracic spine in 2 cases, in the lower thoracic (T7-Th12) in 11 cases, and in the lumbar spine in 4 cases. Microsurgical shunt interruption was performed in all, followed by epidural arteries coagulation in 12 cases.

RESULTS

In the long term, improvement or achievement of a good stable condition was observed in 13 patients (76%), and no patient deteriorated. All 5 paraplegic patients improved by at least 1 grade in MCS. Satisfactory results (modified McCormick Scale grades I-II) were found in 10 patients (59%), and 15(88%) were independent. Postoperative complications occurred in 4 patients (24%), two of them (12%) required revision surgery for epidural hematoma. The success rate was 94%; one patient required revision surgery for recurrent SDAVF. Better neurological condition on admission (p=0.0098) and age >60 years (p=0.0498) were the factors associated with satisfactory outcome.

CONCLUSIONS

Microsurgical closing of a SDAVF brings good and stable results over time. Aggressive treatment should be attempted even in cases of total loss of spinal cord function. Neurological condition before surgery and age may influence the outcome.

Postural stability in patients with chronic subdural hematoma

BACKGROUND

Gait disturbances and falls are common in patients with chronic subdural hematoma (cSDH). Postural stability is mainly visually assessed and has not been described using an objective and quantitative measurement tool. The objective of this prospective study was to evaluate postural stability in cSDH patients by measuring trunk sway during stance and gait compared to healthy elderly (HE). It was also to evaluate the relationships among postural stability and age, hematoma size, brain midline shift and hematoma location.

METHODS

Using a gyroscopic method, trunk sway was measured in 22 cSDH patients preoperatively, 5 postoperatively and 58 HE during seven standing and walking tasks. Trunk sway amplitude and velocity in the anterior-posterior and medial-lateral directions were assessed.

RESULTS

Postural stability was reduced in the cSDH group compared to HE for all standing tasks. During gait, the sway angle was increased while velocity was decreased in the cSDH group. Only 18 % of the patients could perform all tasks without losing their balance. Postoperatively, postural stability was normalized in the medial-lateral direction during standing. There were no correlations among age, hematoma size, brain midline shift or location of the hematoma and trunk sway.

CONCLUSIONS

The majority of cSDH patients had reduced postural stability that was partly reversed soon after surgery. It was not correlated to hematoma characteristics, indicating that an increased risk to fall is present regardless of hematoma size and midline shift. This must be accounted for when handling these patients and measures taken to prevent further fall accidents during hospital stays.

Chronic subdural hematoma

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. There is lack of uniformity in the treatment of CSDH amongst surgeons in terms of various treatment strategies. Clinical presentation may vary from no symptoms to unconsciousness. CSDH is usually diagnosed by contrast-enhanced computed tomography scan. Magnetic resonance imaging (MRI) scan is more sensitive in the diagnosis of bilateral isodense CSDH, multiple loculations, intrahematoma membranes, fresh bleeding, hemolysis, and the size of capsule. Contrast-enhanced CT or MRI could detect associated primary or metastatic dural diseases. Although definite history of trauma could be obtained in a majority of cases, some cases may be secondary to coagulation defect, intracranial hypotension, use of anticoagulants and antiplatelet drugs, etc., Recurrent bleeding, increased exudates from outer membrane, and cerebrospinal fluid entrapment have been implicated in the enlargement of CSDH. Burr-hole evacuation is the treatment of choice for an uncomplicated CSDH. Most of the recent trials favor the use of drain to reduce recurrence rate. Craniotomy and twist drill craniostomy also play a role in the management. Dural biopsy should be taken, especially in recurrence and thick outer membrane. Nonsurgical management is reserved for asymptomatic or high operative risk patients. The steroids and angiotensin converting enzyme inhibitors may also play a role in the management. Single management strategy is not appropriate for all the cases of CSDH. Better understanding of the nature of the pathology, rational selection of an ideal treatment strategy for an individual patient, and identification of the merits and limitations of different surgical techniques could help in improving the prognosis.

Chronic subdural hematoma: Surgical management and outcome in 986 cases: A classification and regression tree approach

BACKGROUND

Chronic subdural hematoma (CSDH) is one of the most common clinical entities in daily neurosurgical practice which carries a most favorable prognosis. However, because of the advanced age and medical problems of patients, surgical therapy is frequently associated with various complications. This study evaluated the clinical features, radiological findings, and neurological outcome in a large series of patients with CSDH.

METHODS

A classification and regression tree (CART) technique was employed in the analysis of data from 986 patients who were operated at Asclepeion General Hospital of Athens from January 1986 to December 2011. Burr holes evacuation with closed system drainage has been the operative technique of first choice at our institution for 29 consecutive years. A total of 27 prognostic factors were examined to predict the outcome at 3-month postoperatively.

RESULTS

Our results indicated that neurological status on admission was the best predictor of outcome. With regard to the other data, age, brain atrophy, thickness and density of hematoma, subdural accumulation of air, and antiplatelet and anticoagulant therapy were found to correlate significantly with prognosis. The overall cross-validated predictive accuracy of CART model was 85.34%, with a cross-validated relative error of 0.326.

CONCLUSIONS

Methodologically, CART technique is quite different from the more commonly used methods, with the primary benefit of illustrating the important prognostic variables as related to outcome. Since, the ideal therapy for the treatment of CSDH is still under debate, this technique may prove useful in developing new therapeutic strategies and approaches for patients with CSDH.

Multiple Densities of the Chronic Subdural Hematoma in CT Scans

Objective

Density of the chronic subdural hematoma (cSDH) is variable. It often appears to be mixed density. Multiple densities of cSDH may result from multiple episodes of trauma. We investigated the frequency of mixed density and the causes of head injuries representing each density.

Methods

We could collect 242 cases of chronic SDH. The cSDHs were classified into four groups; hypodensity, homogeneous isodensity, layered type, and mixed type on the basis of CT scans.

Results

The density of cSDH was isodense in 115 patients, hypodense in 31 patients, mixed in 79 cases, and layered in 17 cases. The cSDH was on the left side in 115 patients, on the right side in 70 patients, and bilateral in 40 patients. The history of trauma was identifiable in 122 patients. The etiology could be identified in 67.7% of the hypodense hematomas, while it was obscure in 59.5% of the mixed hematomas.

Conclusion

Mixed density of cSDH results from multiple episodes of trauma, usually in the aged. It is hard to remember all the trivial traumas for the patients with the mixed density cSDHs. Although there were membranes within the mixed density hematomas, burr-holes were usually enough to drain the hematomas.

Volume and densities of chronic subdural haematoma obtained from CT imaging as predictors of postoperative recurrence: a prospective study of 107 operated patients

Background

Chronic subdural haematoma (CSDH) is a common entity in neurosurgery with a considerable postoperative recurrence rate. Computerised tomography (CT) scanning remains the most important diagnostic test for this disorder. The aim of this study was to characterise the relationship between the recurrence of CSDH after treatment with burr-hole irrigation and closed-system drainage technique and CT scan features of these lesions to assess whether CT findings can be used to predict recurrence.

Methods

We investigated preoperative and postoperative CT scan features and recurrence rate of 107 consecutive adult surgical cases of CSDH and assessed any relationship with univariate and multivariate regression analyses.

Results

Seventeen patients (15.9 %) experienced recurrence of CSDH. The preoperative haematoma volume, the isodense, hyperdense, laminar and separated CT densities and the residual total haematoma cavity volume on the 1st postoperative day after removal of the drainage were identified as radiological predictors of recurrence. If the preoperative haematoma volume was under 115 ml and the residual total haematoma cavity volume postoperatively was under 80 ml, the probability of no recurrence was very high (94.4 % and 97.4 % respectively).

Conclusions

These findings from CT imaging may help to identify patients at risk for postoperative recurrence.