Effects of surface profile on porcine dural mechanical properties.

BACKGROUND: Cerebrospinal fluid leakage through the spinal meninges is difficult to diagnose and treat. Moreover, its underlying mechanism remains unknown. Considering that the dura mater is structurally the strongest and outermost membrane among the three-layered meninges, we hypothesized that a dural mechanical tear would trigger spontaneous cerebrospinal fluid leakage, especially when a traumatic loading event is involved. Thus, accurate biomechanical properties of the dura mater are indispensable for improving computational models, which aid in predicting blunt impact injuries and creating artificial substitutes for transplantation and surgical training. METHOD: We characterized the surface profile of the spinal dura and its mechanical properties (Young's moduli) with a distinction of its inherent anatomical sites (i.e., the cervical and lumbar regions as well as the dorsal and ventral sides of the spinal cord). FINDINGS: Although the obtained Young's moduli exhibited no considerable difference between the aforementioned anatomical sites, our results suggested that the wrinkles structurally formed along the longitudinal direction would relieve stress concentration on the dural surface under in vivo and supraphysiological conditions, enabling mechanical protection of the dural tissue from a blunt impact force that was externally applied to the spine. INTERPRETATION: This study provides fundamental data that can be used for accurately predicting cerebrospinal fluid leakage due to blunt impact trauma.

Dural Reconstruction Materials for the Repairing of Spinal Neoplastic Cerebrospinal Fluid Leaks.

Spinal tumors often lead to more complex complications than other bone tumors. Nerve injuries, dura mater defect, and subsequent cerebrospinal fluid (CSF) leakage generally appear in spinal tumor surgeries and are followed by serious adverse outcomes such as infections and even death. The use of suitable dura mater replacements to achieve multifunctionality in fluid leakage plugging, preventing adhesions, and dural reconstruction is a promising therapeutic approach. Although there have been innovative endeavors to manage dura mater defects, only a handful of materials have realized the targeted multifunctionality. Here, we review recent advances in dura repair materials and techniques and discuss the relative merits in both preclinical and clinical trials as well as future therapeutic options. With these advances, spinal tumor patients with dura mater defects may be able to benefit from novel treatments.

Prx1 + and Hic1+ Mesenchymal Progenitors Are Present Within the Epidural Fat and Dura Mater and Participate in Dural Injury Repair.

Epidural fat is commonly discarded during spine surgery to increase the operational field. However, mesenchymal progenitor cells (MPCs) have now been identified in human epidural fat and within the murine dura mater. This led us to believe that epidural fat may regulate homeostasis and regeneration in the vertebral microenvironment. Using two MPC lineage tracing reporter mice (Prx1 and Hic1), not only have we found that epidural fat MPCs become incorporated in the dura mater over the course of normal skeletal maturation, but have also identified these cells as an endogenous source of repair and regeneration post-dural injury. Moreover, our results reveal a partial overlap between Prx1+ and Hic1+ populations, indicating a potential hierarchical relationship between the two MPC populations. This study effectively challenges the notion of epidural fat as an expendable tissue and mandates further research into its biological function and relevance.

Dural Tear Does not Increase the Rate of Venous Thromboembolic Disease in Patients Undergoing Elective Lumbar Decompression with Instrumented Fusion.

OBJECTIVE: Evaluate if dural tears (DTs) are an indirect risk factor for venous thromboembolic disease through increased recumbency in patients undergoing elective lumbar decompression and instrumented fusion. METHODS: This was a retrospective cohort study of consecutive patients undergoing elective lumbar decompression and instrumented fusion at a single institution between 2016 and 2019. Patients were divided into cohorts: those who sustained a dural tear and those who did not. The cohorts were compared using Student's t-test or Wilcoxon Rank Sum for continuous variables and Fisher exact or chi-squared test for nominal variables. RESULTS: Six-hundred and eleven patients met inclusion criteria, among which 144 patients (23.6%) sustained a DT. The DT cohort tended to be older (63.6 vs. 60.6 years, P = 0.0052) and have more comorbidities (Charlson Comorbidity Index 2.75 vs. 2.35, P = 0.0056). There was no significant difference in the rate of symptomatic deep vein thrombosis (2.1% vs. 2.6%, P = 1.0) or pulmonary embolus (1.4% vs. 1.50%, P = 1.0). Intraoperatively, DT was associated with increased blood loss (754 mL vs. 512 mL, P < 0.0001), operative time (224 vs. 195 minutes, P < 0.0001), and rate of transfusion (19.4% vs. 9.4%, P = 0.0018). Postoperatively, DT was associated with increased time to ambulation (2.6 vs. 1.4 days, P < 0.0001), length of stay (5.8 vs. 4.0 days, P < 0.0001), and rate of discharge to rehab (38.9 vs. 25.3%, P = 0.0021). CONCLUSIONS: While DTs during elective lumbar decompression and instrumentation led to later ambulation and longer hospital stays, the increased recumbency did not significantly increase the rate of symptomatic venous thromboembolic disease.

Initial Results of Precision Treatment of Postoperative Cerebrospinal Fluid Leak with Ultrasound-Guided Epidural Blood Patch.

BACKGROUND: Incidental durotomy, a known complication of spinal surgery, can lead to persistent cerebrospinal fluid leak and pseudomeningocele if unrecognized or incompletely repaired. We describe the use of ultrasound to visualize the site of durotomy, observe the aspiration of the pseudomeningocele, and guide the precise application of an ultrasound-guided epidural blood patch (US-EBP), under direct visualization in real time. METHODS: A retrospective review was performed to determine demographic, procedural, and outcome characteristics for patients who underwent US-EBP for symptomatic postoperative pseudomeningocele. RESULTS: Overall, 48 patients who underwent 49 unique episodes of care were included. The average age and body mass index were 60.5 (±12.6) years and 27.8 (±4.50) kg/m2, respectively. The most frequent index operation was laminectomy (24.5%), and 36.7% of surgeries were revision operations. Durotomy was intended or recognized in 73.4% of cases, and the median time from surgery to symptom development was 7 (interquartile range 4-16) days. A total of 61 US-EBPs were performed, with 51.0% of patients experiencing resolution of their symptoms after the first US-EBP. An additional 20.4% were successful with multiple US-EBP attempts. Complications occurred in 14.3% of cases, and the median clinical follow-up was 4.3 (interquartile range 2.4-14.5) months. CONCLUSIONS: This manuscript represents the largest series in the literature describing US-EBP for the treatment of postoperative pseudomeningocele. The success rate suggests that routine utilization of US-guided EBP may allow for targeted treatment of pseudomeningoceles, without the prolonged hospitalization associated with lumbar drains or the risks of general anesthesia and impaired wound healing associated with surgical revision.

Effectiveness of Repair Techniques for Spinal Dural Tears: A Systematic Review.

BACKGROUND: Incidental or intentional durotomy in spine surgery is associated with a risk of cerebrospinal fluid (CSF) leakage and reoperation. Several strategies have been introduced, but the incomplete closure is still relatively frequent and troublesome. In this study, we review current evidence on spinal dural repair strategies and evaluate their efficacy. METHODS: PubMed, Web of Science, and Scopus were used to search primary studies about the repair of the spinal dura with different techniques. Of 265 articles found, 11 studies, which specified repair techniques and postoperative outcomes, were included for qualitative and quantitative analysis. The primary outcomes were CSF leakage and postoperative infection. RESULTS: The outcomes of different dural repair techniques were available in 776 cases. Pooled analysis of 11 studies demonstrated that the most commonly used technique was a combination of primary closure, patch or graft, and sealant (22.7%, 176/776). A combination of primary closure and patch or graft resulted in the lowest rate of CSF leakage (5.5%, 7/128). In this study, sealants as an adjunct to primary closure (13.7%, 18/131) did not significantly reduce the rate of CSF leakage compared with primary closure alone (17.6%, 18/102). The rates of infection and postoperative neurologic deficit were similar regardless of the repair techniques. CONCLUSIONS: Although the use of sealants has become prevalent, available sealants as an adjunct to primary closure did not reduce the rate of CSF leakage compared with primary closure. The combination of primary closure and patches or grafts could be effective in decreasing postoperative CSF leakage.

Symptomatic Intracranial Hemorrhage after Dural Tear in Spinal Surgery-A Series of 10 Cases and Review of the Literature.

OBJECTIVE: Intracranial hemorrhage (IH) after spinal surgery is a rare but potentially life-threatening complication. Knowledge of predisposing factors and typical clinical signs is essential for early recognition, helping to prevent an unfavorable outcome. METHODS: A retrospective analysis was performed of patients with IH after spinal surgery treated in our institution between 2012 and 2018. The literature dealing with IH complicating spinal surgery was reviewed. RESULTS: Our investigation found 10 patients with IH (6 female and 4 male). To the best of our knowledge, this is the largest series reported so far. The assumable incidence of IH after spinal surgery in our population was 0.0657%. Durotomy was noticed in 6 patients, all of whom were treated according to a local standard protocol. In 4 patients, the dural tear was occult. Hemorrhage occurred mostly in the cerebellar compartment. Eight of 10 patients had long-standing arterial hypertension, which seems to be a risk factor (hazard ratio, 1.58). Five patients were treated conservatively, whereas 3 required a cerebrospinal fluid (CSF) diversion procedure. In 2 patients, revision surgery with duraplasty was necessary. Seven patients were discharged with little to no neurologic symptoms, and 3 had significant deterioration. One patient died because of brainstem herniation. Review of the literature identified 54 articles with 72 patients with IH complicating spinal surgery. CONCLUSIONS: Patients with intraoperative CSF loss should be kept under close supervision postoperatively. After opening of the dura, a watertight closure should be attempted. The use of subfascial suction drainage in cases of a dural tear as well as preexistent arterial hypertension seems to be a risk factor for the development of IH. Intracranial bleeding must be considered in every patient with unexplained neurologic deterioration after spinal surgery and should be ruled out by cranial imaging. To ensure early recognition and prevent an unfavorable outcome, a high index of suspicion is required, especially in revision spinal surgery. The treatment is specific to the extent and location of the IH, thus dictating the outcome. In most patients, conservative treatment led to a good outcome. CSF diversion measures may be necessary in patients with compression or obstruction of the fourth ventricle. Large hematomas with mass effect may require decompressive surgery.

Acute-Phase Intraoperative Findings of Traumatic Spinal Cerebrospinal Fluid Leakage.

The acute-stage intraoperative findings of the spinal dural laceration in patients with traumatic cerebrospinal fluid (CSF) leakage have not been clearly revealed so far. Herein, we report an interesting case of traumatic CSF leakage in a patient who underwent acute-stage direct closure for a dural laceration similar to a stab at the C1/2 level. Because a 41-year-old man strongly twisted his neck, he had a typical orthostatic headache. Whole-spine T2 fat-saturated magnetic resonance imaging and computed tomographic myelography were examined, and fluid collection between the intrathecal site and epidural dorsal space, including soft tissue, was confirmed as a direct CSF leakage at the C1/2 level. Direct surgical closure was performed 13 days after the onset of symptoms, and dural laceration with sharp edges was detected on the right side at the C1/2 level. The laceration was sutured and coated with dural sealant. Finally, the patient's orthostatic headache was relieved completely after the operation.

Cerebrospinal fluid leaks secondary to dural tears: a review of etiology, clinical evaluation, and management.

OBJECTIVE: Damage to the dura mater often occurs in trauma cases of the head and spine, surgical procedures, lumbar punctures, and meningeal diseases. The resulting damage from dural tears, or durotomy, causes cerebrospinal fluid (CSF) to leak out into the surrounding space. The CSF leak induces intracranial hypotension, which can clinically present with a range of symptoms not limited to positional headaches which can confound accurate diagnosis. Current methods of evaluation and management of dural tears are discussed herewith, as well as the present understanding of its etiology, which may be classified as related to surgery, procedure, trauma, or connective tissue disorder. METHODS: We piloted a MEDLINE® database search of literature, with emphasis on the previous five years, combining keywords such as "cerebrospinal fluid leak," "surgery," "procedure," and "trauma" to yield original research articles and case reports for building a clinical profile. RESULTS: Patients with suspected dural tears should be evaluated based on criteria set by the International Headache Society, radiological findings, and a differential diagnosis to accurately identify the tear and its potential secondary complications. Afflicted patients may be treated promptly with epidural blood patches, epidural infusions, epidural fibrin glue, or surgical repair. At this time, epidural blood patches are the first line of treatment. Dural tears can be prevented to an extent by utilizing minimally invasive techniques and certain positions for lumbar puncture. Surgical, trauma, lumbar puncture, and epidural injection patients should be observed very carefully for dural tears and CSF leaks as the presenting clinical manifestations can be highly individualized and misguiding. CONCLUSION: Because studies have demonstrated a high frequency of dural tears, particularly in spinal surgery patients, there is a need for prospective studies so that clinicians can develop an elaborate prevention strategy and response to avoid serious, unseen complications.

Pedicled Multifidus Muscle Flap To Treat Inaccessible Dural Tear In Spine Surgery: Technical Note And Preliminary Experience.

OBJECTIVE: To assess the usefulness, feasibility, and limitations of pedicled multifidus muscle flaps (PMMFs) for the treatment of inaccessible dural tears during spine surgery. METHODS: The technique of PMMF harvesting was investigated together with relevant anatomy. We prospectively evaluated 8 patients treated with the PMMF technique between January 2017 and December 2019. Results were compared with a retrospective series of 9 patients treated with a standard technique between January 2014 and December 2016. Inclusion criteria were inaccessible dural tear or dural tear judged not amenable to direct repair because of tissue loosening. Exclusion criteria were surgical treatment of intradural disease. Clinical and demographic data of all patients were collected. Clinical evaluations were performed according to American Spinal Injury Association criteria and Oswestry Disability Index. Preoperative and postoperative computed tomography was performed in all patients. The primary end point was wound healing (cerebrospinal fluid leakage, infection, and fluid collection); secondary end points were neurologic outcome and complications. RESULTS: Control group: 1 death as a result of wound infection secondary to cerebrospinal fluid fistula and 2 patients needed lumbar subarachnoid drain; neurologic outcome: 3 patients improved and 6 were unchanged. Flap group: no wound-related complications were observed; neurologic outcome: 3 patients improved and 5 were unchanged. No flap-related complications were described. Flap harvesting was feasible in all cases, with an average 20 minutes adjunctive surgical time. CONCLUSIONS: The PMMF technique was feasible and safe; in this preliminary experience, its use is associated with lower complications as a result of dural tears but larger series are needed to confirm its effectiveness.

Outcomes of dogs with progressive myelomalacia treated with hemilaminectomy or with extensive hemilaminectomy and durotomy.

OBJECTIVE: To evaluate the ability of extensive hemilaminectomy and durotomy (EHLD) to control progressive myelomalacia (PMM) in dogs. STUDY DESIGN: Retrospective clinical study. ANIMALS: Twenty-eight client owned dogs that underwent EHLD (n = 10) or HL alone (n = 18). METHODS: After diagnosis by MRI, dogs were immediately treated with HL alone or EHLD at the site of intramedullary hyperintensity on T2-weighted (T2W)-MRI. Medical records were retrospectively reviewed. Follow-up data were collected via telephone interviews with the referring veterinarian and a standardized questionnaire. Postoperative survival outcome between groups was compared (log-rank test) by using Cox's proportional hazard analysis with baseline characteristics entered as covariates. RESULTS: The survival rate was higher in the EHLD group (P = .03) compared with the HL-alone group. Eleven of 18 dogs treated with HL survived, while seven of 18 dogs died (median, 5 days after surgery). In the EHLD group, 10 of 10 dogs survived postoperatively. Baseline characteristics were not associated with postoperative survival outcomes. According to multivariate analysis, EHLD was the independent factor associated with an increase in survival rate (P = .0002). CONCLUSION: EHLD durotomy at the intramedullary hyperintense region on T2W-MRI improved the survival rate of dogs with PMM compared with dogs treated with standard HL. CLINICAL SIGNIFICANCE: This study provides evidence that supports treatment with EHLD in dogs with PMM. Additional prospective studies are required.

Reconstruction of skull and dural defects using anterolateral thigh flaps: A STROBE-compliant article.

It is difficult to repair large skull and dural defects. We observed the therapeutic effects of anterolateral thigh flaps with vascular fascia lata for repairing large skull and dural defects.From December 2008 to June 2019, we repaired large skull and dural defects for 28 cases including 12 cases with scalp malignant tumor and 16 cases requiring removal of titanium mesh which had been once placed due to craniocerebral trauma. The scalp malignant tumor invaded full-thickness skull in 12 cases; and invaded cervical lymph nodes, dura mater or brain tissue in 3 cases. In the 12 cases with scalp malignant tumor, the scalp defects of 12 cm × 9 cm to 22 cm × 18 cm and skull defects of 9 cm × 7 cm to 15 cm × 12 cm after radical tumor resection were repaired using anterolateral thigh flaps of 14 cm × 11 cm to 23 cm × 19 cm with fascia lata of 10 cm × 8 cm to 16 cm × 12 cm. Postoperative radiotherapy and chemotherapy were also performed in the 3 cases with tumor metastasis. In the 16 cases requiring removal of titanium mesh, the skull and dural defects of 8 cm × 7 cm to 15 cm × 11 cm after removal of titanium mesh were repaired using anterolateral thigh flaps of 10 cm × 8 cm to 16 cm × 12 cm.In all cases, the transplanted anterolateral thigh flap with fascia lata survived after surgery and no vascular crisis occurred. During the followup of 8 months to 9 years, the flap appearance in the head-repaired area was fine, no external hernia of brain tissue occurred, the appearance of the femoral donor site was acceptable, and femoral muscle strength and movements were normal in all cases. The 12 cases with scalp malignant tumor had no local recurrence or distant metastasis.Repairing the skull and dural defects caused by radical surgery for scalp malignant tumor or removal of titanium mesh using anterolateral thigh flaps with vascular fascia lata, is effective. The appearance in the head-repaired area is fine without external hernia of brain tissue.

Dural Leak: Is It Deterrent to Outcomes in Spine Surgery?: 10 Years Retrospective Analysis of Incidence, Management Protocol, and Surgical Outcomes.

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: To review the incidence of dural leaks, evaluate the efficacy of primary closure of durotomy and to study its effect on clinical outcome. The secondary aim is to classify the dural leaks and proposing a treatment algorithm for dural leaks. SUMMARY OF BACKGROUND DATA: Dural leaks are described as one of the fearful complications in spine surgery. Literature evaluating the actual incidence, ideal treatment protocol, efficacy of primary repair techniques and its effects on long-term surgical outcomes are scanty. METHODS: It was a retrospective analysis of 5390 consecutively operated spine cases over a period of 10 years. All cases were divided into two groups-study group (with dural leak-255) and control group (without dural leak-5135). Dural leaks were managed with the proposed treatment algorithm. Blood loss, surgical time, hospital stay, time for return to mobilization, pain free status, and clinical outcome score (ODI, VAS, NDI, and Wang criteria) were assessed in both groups at regular intervals. The statistical comparison between two groups was established with chi-square and t-tests. RESULTS: The overall incidence of dural leaks was 4.73% with highest incidence in revision cases (27.61%). There was significant difference noted in mean surgical blood loss (P 0.001), mean hospital stay (P 0.001), time to achieve pain-free status after surgery, and return to mobilization between two groups. However, no significant difference was noted in operative time (P 0.372) and clinical outcome scores at final follow-up between the two groups. CONCLUSION: Primary closure should be undertaken in all amenable major dural leak cases. Dural leaks managed as proposed by the author's treatment algorithm have shown a comparable clinical outcome as in patients without dural leaks. Dural leak is a friendly adverse event that does not prove a deterrent to long-term clinical outcome in spine surgeries. LEVEL OF EVIDENCE: 4.

Management of Incidental Durotomy: Results from a Nationwide Survey Conducted by the French Society of Spine Surgery.

OBJECTIVE: To obtain real-life data on the most common practices used for management of incidental durotomy (ID) in France. METHODS: Data were collected from spinal surgeons using a practice-based online questionnaire. The survey comprised 31 questions on the current management of ID in France. The primary outcome was the identification of areas of consensus and uncertainty on ID follow-up. RESULTS: A total of 217 surgeons (mainly orthopaedic surgeons and neurosurgeons) completed the questionnaire and were included in the analysis. There was a consensus on ID repair with 94.5% of the surgeons considering that an ID should always be repaired, if repairable, and 97.2% performing a repair if an ID occurred. The most popular techniques were simple suture or locked continuous suture (48.3% vs. 57.8% of surgeons). Nonrepairable IDs were more likely to be treated with surgical sealants than with an endogenous graft (84.9% vs. 75.5%). Almost two thirds of surgeons (71.6%) who adapted their standard postoperative protocol after an ID recommended bed rest in the supine position. Among these, 48.8% recommended 24 hours of bed rest, while 53.5% recommended 48 hours of bed rest. The surgeons considered that the main risk factors for ID were revision surgery (98.6%), patient's age (46.8%), surgeon's exhaustion (46.3%), and patient's weight (21.3%). CONCLUSIONS: This nationwide survey reflects the lack of a standardized management protocol for ID. Practices among surgeons remain very heterogeneous. Further consensus studies are required to develop a standard management protocol for ID.

Incidental Durotomy Following Transforaminal Lumbar Interbody Fusion Performed with the Modified Wiltse Approach.

PURPOSE: Incidental durotomy is an intraoperative complication that occurs in 3 to 27% of lumbar spine surgeries. It has been reported more commonly following revision spinal procedures. STUDY OBJECTIVES: To investigate the frequency of incidental durotomy while performing transforaminal lumbar interbody fusion (TLIF) using the modified Wiltse approach. A secondary goal was to compare the incidence of durotomy in patients undergoing primary spine surgery with those undergoing revision surgery. METHODS: A group of consecutive patients who had undergone (TLIF) in the last 10 years ending in 2015 were enrolled in the study. All patients underwent TLIF via the modified Wiltse approach that included a central midline skin incision, followed by a paravertebral blunt dissection of the paraspinal muscles to reach the transverse processes. The deep paravertebral dissection was done conservatively, one side at a time. Demographic and clinical data were collected when relevant to the comparison. RESULTS: The study cohort encompassed 257 patients: 200 primary cases and 57 revisions. The frequency of incidental durotomy was equal in both groups: 3.5% each (7/200 and 2/57). All durotomies were repaired primarily. No other immediate or late complications were observed during follow-up. CONCLUSION: The present study displays a limited incidence of durotomy in the primary interventions and to a lesser degree in the revisions, all of which had used a TLIF performed with the modified Wiltse approach. This procedure probably circumvented the need for further revisions.

Growing skull fracture with an atypical mechanism: a case report.

Growing skull fractures (GSFs) are well-known but rare causes of pediatric head trauma. They generally occur several months after a head injury, and the main lesion is located under the periosteum. We herein report a case involving a 3-month-old boy with GSF that developed by a different mechanism than previously considered. It developed 18 days after the head injury. A large mass containing cerebrospinal fluid and brain tissue was present within the periosteum. A good outcome was obtained with early strategic surgery. Injury to the inner layer of the periosteum and sudden increase in intracranial pressure might be related to GSF in this case.

Postoperative iatrogenic spinal cord herniation: three case reports with a literature review.

Although a majority of spinal cord herniation reportedly occurs idiopathically, postoperative iatrogenic spinal cord herniation is rare. Therefore, the incidence rate, pathogenic mechanism, and clinical outcomes are not clear. We present three cases of postoperative iatrogenic spinal cord herniation and present a literature review. Our data base included 32253 patients who underwent spinal surgery, and among these patients, 3 showed postoperative spinal cord herniation. Postoperative spinal cord herniation was observed in a 55-year-old man and a 60-year-old man. Both these patients underwent cervical laminoplasty for degenerative cervical myelopathy; however, intraoperative dural tear was reported. They presented with severe quadriplegia and sensory disorders at 8 years and 2 months after initial surgery. The third case of postoperative spinal cord herniation was of a 47-year-old woman who underwent Th11/12 schwannoma resection. Her neurological symptoms did not improve after tumor resection, and MRI at 2 months after surgery revealed spinal cord herniation. All the 3 patients underwent spinal cord reduction surgery; one patient showed sufficient neurological improvement while 2 patients with cervical spinal cord herniation showed limited neurological improvement due to preoperative severe quadriplegia. Although postoperative iatrogenic spinal cord herniation is a relatively rare pathology, careful observation with postoperative MRI is required in cases of patients with new neurological symptoms after dural injury and durotomy.

Closed-head injuries followed by detached brain tissue in the external auditory canals.

We describe five cases of fatally injured males (occupational accident, car driver, pedestrian, motorcyclist and suicidal jump from great height) with one universal autopsy finding - the presence of brain tissue in one or both auditory canals. Internal examination revealed that all victims had multiple head fractures with dura lacerations. In four cases, the petrous part of the temporal bone was fractured (hinge fracture), while in one case the fracture of both the petrous part of the temporal bones and the occipital bone (ring fracture) was present. In all of these cases, considerable pressure was applied to the head, pushing brain tissue equally in all directions (due to incompressibility of the tissue). The tissue followed the path of least resistance, going through the lacerated dura into the fractured petrous part of the temporal bones and finally reaching the middle ear cavity and auditory canal. This phenomenon is almost exclusively encountered in closed-head injuries. In an open-head injury, brain tissue would be expelled through the open bone fracture and scalp wound. The presence of brain tissue in the ears could indicate a hinge or ring fracture in a closed-head injury which occurred as the result of excessive impulse force or considerable pressure applied to the head, i.e. the head was compressed and/or squeezed.

Transdural Thoracic Disk Herniation with Longitudinal Slitlike Dural Defect Causing Intracranial Hypotension: Report of 2 Cases.

BACKGROUND: Intracranial hypotension (IH) has a widely variable clinical and radiologic presentation. Secondary IH may be caused by degenerative spine disorders and in particular by thoracic disk herniations (TDHs). METHODS: We present 2 patients with a transdural TDH, a secondary IH, and superficial siderosis in 1. RESULTS: Case 1 presented with headache, cognitive decline, staggering gait, bilateral subdural effusions, cerebral sagging, an extradural spinal cerebrospinal fluid (CSF) collection suggesting secondary IH, and a calcified TDH at T9-T10. Case 2 presented with intermittent pain at the craniocervical junction provoked exclusively by specific physical activities, superficial siderosis mainly in the posterior fossa, an extradural spinal CSF collection, and a calcified TDH at T7-T8 yet no intracranial signs of IH. In both cases, using strict thoracoscopic technique, we removed a transdural TDH and reconstructed an underlying longitudinal slitlike dural defect with smooth lining. Follow-up magnetic resonance imaging scans confirmed a dramatically improved situation without residual extradural intraspinal CSF collection or signs of IH. CONCLUSIONS: This paper adds to the evidence that some cases of IH and even superficial siderosis are caused by transdural erosion of a TDH that may be otherwise asymptomatic. The dura may degenerate due to chronic compression, and a longitudinal slitlike dural defect with smooth lining may develop, causing continuous (Case 1) or intermittent (Case 2) intraspinal CSF leakage. To the best of our knowledge, such dural defects closely resembling the ones observed in idiopathic spinal cord herniation have never been demonstrated on intraoperative endoscopic video in IH patients.

A systematic review and meta-analysis on the management of accidental dural tears in spinal surgery: drowning in information but thirsty for a clear message.

PURPOSE: To systematically review the published techniques for dural tear (DT) repair in spinal surgery to determine the repair method associated with the lowest failure rate. METHOD: A systematic literature search was conducted. Studies reporting the treatment of accidental DT in elective spinal surgery were selected and reviewed with regards to the incidence of DT, repair techniques and outcome. Meta-analysis of proportions was used to compare the outcome of different repair techniques and their adjuncts. RESULTS: Forty-nine studies were included with a total of 3822 DT cases. The outcome of different dural repair techniques was available for 2329(60.9%) cases. The overall pooled risk of DT was 0.052(0.040-0.065) and the overall pooled proportion of failed DT treatment regardless of the treatment method was 0.061(0.044-0.083). The proportion of failure varied according to the repair method. The overall proportion of failure following direct repair with suture (with or without any other augment) was lower than indirect repair (with sealant and or patch): 0.037 (0.024-0.053) versus 0.047 (0.026-0.074), respectively. Bed rest and the use of sub-fascial drain were not associated with improved outcome according to our results. CONCLUSION: Direct repair was associated with low proportion of failure. Howver, the approach to DT treatment was commonly determined on an ad hoc basis according to surgeons' preferences, and few followed defined management protocols. Future studies reporting DT treatment ought to categorise the treatment outcome according to the complexity of the DT and the specific treatment used, thus improving research quality in the field.