Haemorrhage associated with silastic dural substitute

Tensile properties of human spinal dura mater and pericranium

Autologous pericranium is a promising dural graft material. An optimal graft should exhibit similar mechanical properties to the native dura, but the mechanical properties of human pericranium have not been characterized, and studies of the biomechanical performance of human spinal dura are limited. The primary aim of this study was to measure the tensile structural and material properties of the pericranium, in the longitudinal and circumferential directions, and of the dura in each spinal region (cervical, thoracic and lumbar) and in three directions (longitudinal anterior and posterior, and circumferential). The secondary aim was to determine corresponding constitutive stress-strain equations using a one-term Ogden model. A total of 146 specimens were tested from 7 cadavers. Linear regression models assessed the effect of tissue type, region, and orientation on the structural and material properties. Pericranium was isotropic, while spinal dura was anisotropic with higher stiffness and strength in the longitudinal than the circumferential direction. Pericranium had lower strength and modulus than spinal dura across all regions in the longitudinal direction but was stronger and stiffer than dura in the circumferential direction. Spinal dura and pericranium had similar strain at peak force, toe, and yield, across all regions and directions. Human pericranium exhibits isotropic mechanical behavior that lies between that of the longitudinal and circumferential spinal dura. Further studies are required to determine if pericranium grafts behave like native dura under in vivo loading conditions. The Ogden parameters reported may be used for computational modeling of the central nervous system. Graphical abstract.

Safety of the nonabsorbable dural substitute in decompressive craniectomy for severe traumatic brain injury

BACKGROUND

Artificial dural substitutes are increasingly being used in decompressive craniectomy to prevent peridural fibrosis and facilitate cranioplasty for patients with head injury. The safety of the dural substitute should be systemically evaluated. We focus on Neuro-Patch (B. Braun, Boulogne, France), a nonabsorbable substitute and commonly used by neurosurgeons.

METHODS

In this retrospective study, 132 patients undergoing 135 craniectomies and cranioplasties for traumatic brain injury were enrolled. We subdivided the operations into two groups on the basis of whether Neuro-Patch was used (N = 50) or not (N = 85). Risk factors of neurosurgical site infection were assessed first. Then, we compared the occurrence of infective, hemorrhagic, and hydrodynamic morbidities after craniectomy and cranioplasty between the two groups.

RESULTS

The incidence of neurosurgical site infection after craniectomy or cranioplasty showed no intergroup difference (p = 1.000). Postoperatively, extra-axial hematoma, which consists of subdural or epidural hematoma, occurred in 9 of 50 craniectomies (18.00%) with Neuro-Patch and 3 of 85 craniectomies (3.53%) without Neuro-patch, which was significantly different (p = 0.009). The rates of hydrodynamic morbidities (subdural hygroma or cerebrospinal fluid leakage) after the procedures were similar between the two groups.

CONCLUSIONS

The use of Neuro-Patch does not increase the incidence of neurosurgical site infection and hydrodynamic complications, including subdural hygroma and cerebrospinal fluid leakage, after decompressive craniectomy or cranioplasty for severe traumatic brain injury. However, extra-axial hematoma at the site of craniectomy is more often encountered in patients with Neuro-Patch and forms a compressive lesion on the adjacent brain.

Low-grade infection complicating silastic dural substitute 32 years post-operatively

BACKGROUND

A complication of a silastic dural substitute is described, which appeared after 32 years-by far the longest latency period reported in the literature.

METHODS

Case report and literature review.

RESULTS

In 1971, a 20-year old woman suffered from an acute subdural haematoma and a temporal cerebral contusion due to a motorbike accident. She underwent an operation with evacuation of these and the dura was mended with a silastic duraplasty. Thirty-two years later she deteriorated with increased memory problems and dysphasia. CT revealed an expanding haemorrhagic mass around the previous duraplasty, which demanded surgery with removal of the silastic dural implant and evacuation of the haemorrhagic mass. Although the haemorrhagic mass enveloped the silastic implant, a contribution of the acrylate flap cannot be ruled out. Bacteriological cultures revealed Acinetobacter spp. in the CSF. Adequate post-operative antibiotic treatment was administered. The patient slowly improved, but the complication represented a major setback in her long-term cognitive and communicative functions.

CONCLUSIONS

This case widens the previously reported time-frame of late complications by 60%, from 20 to 32 years, and will hopefully serve to increase the awareness of late infections and haemorrhages induced by silastic dural implants, thereby improving diagnosis and treatment in future cases.

Efficacy and safety of a collagen matrix for cranial and spinal dural reconstruction using different fixation techniques

Object

The use of dural grafts is frequently unavoidable when tension-free dural closure cannot be achieved following neurosurgical procedures or trauma. Biodegradable collagen matrices serve as a scaffold for the regrowth of natural tissue and require no suturing. The aim of this study was to investigate the efficacy and safety of dural repair with a collagen matrix using different fixation techniques.

Methods

A total of 221 patients (98 male and 123 female; mean age 55.6 ± 17.8 years) undergoing cranial (86.4%) or spinal (13.6%) procedures with the use of a collagen matrix dural graft were included in this retrospective study. The indications for use, fixation techniques, and associated complications were recorded.

Results

There were no complications of the dural graft in spinal use. Five (2.6%) of 191 patients undergoing cranial procedures developed infections, 3 of which (1.6%) were deep infections requiring surgical revision. There was no statistically significant relationship between the operative field status before surgery and the occurrence of a postoperative wound infection (p = 0.684). In the 191 patients undergoing a cranial procedure, cerebrospinal fluid (CSF) collection occurred in 5 patients (2.6%) and a CSF fistula in 5 (2.6%), 3 of whom (1.6%) required surgical revision. No patient who underwent an operation with preexisting CSF leakage had postoperative CSF leakage. Postoperative infection significantly increased the risk for postoperative CSF leakage.

The collagen matrix was used without additional fixation in 124 patients (56.1%), with single fixation in 55 (24.9%), and with multiple fixations in 42 (19%). There were no systemic allergic reactions or local skin changes. Follow-up imaging in 112 patients (50.7%) revealed no evidence of any adverse reaction to the collagen graft.

Conclusions

The collagen matrix is an effective and safe cranial and spinal dural substitute that can be used even in cases of an existing local infection. Postoperative deep infection increases the risk for CSF leakage.

Nonsuture dural repair using polyglycolic acid mesh and fibrin glue: clinical application to spinal surgery

BACKGROUND

In spinal surgery, repair of the dura is difficult when it is torn or fragile or is ossified as in cases with ossification of posterior longitudinal ligament. We report our experience with a nonsuture dural repair technique in patients undergoing spinal surgery; it uses a dura substitute composed of polyglycolic acid (PGA) mesh and fibrin glue. Here, we report the efficacy and safety of nonsuture duroplasty using PGA mesh and fibrin glue (PGA-fibrin sheet).

METHODS

The artificial dura mater is composed of a PGA-fibrin sheet. The dural defect is covered with a patch sprayed with fibrin glue without suturing to the dura mater. We first evaluated this technique in an experimental study by performing water leakage tests. Between May 2001 and January 2005, we used it in 160 spinal surgeries that required intraoperative dura repair.

RESULTS

Our preliminary tests showed that the threshold for water pressure without leakage was 161 +/- 42 and 96.5 +/- 32 mm Hg when the unsprayed margin around the perimeter of the patch was 5 and 2 mm, respectively. Of the 160 operated patients, 10 (6.3%) experienced subcutaneous cerebrospinal fluid (CSF) leakage. Of these, 6 required a second operation; in the other 4, the CSF collection diminished spontaneously. There were no other complications such as allergic reaction, adhesion, or infection.

CONCLUSION

In combination with CSF diversion, the PGA-fibrin sheet is a viable alternative method for dural repair in spinal surgery.

Comparison of Deep Wound Infection Rates Using a Synthetic Dural Substitute (Neuro-Patch) or Pericranium Graft for Dural Closure: A Clinical Review of 1 Year

OBJECTIVE

The need to repair dural defects has prompted the use of dura mater substitutes. Many synthetic materials have been used for dural closure. Neuro-Patch (B. Braun Médical S.A., Boulogne, France) is a nonabsorbable microporous fleece composed of polyester urethane that has been approved for human use by the European Union since 1995. To the best of our knowledge, no clinical series with Neuro-Patch have been published thus far, particularly with regard to septic complications. The aim of our study was to compare the safety of Neuro-Patch with that of pericranium graft with regard to postoperative wound infections.

METHODS

This is a retrospective study of 1 year's experience including all patients who underwent dural plasty with a Neuro-Patch (n = 61) or pericranium graft (n = 63). The follow-up period was at least 12 months after surgery. Before wound infection rates in the two groups were compared, factors suspected of being risks for neurosurgical site infection were evaluated.

RESULTS

Patient characteristics (mean age, neurological diagnosis), surgical procedures, prophylactic antibiotics, and risk factors for surgical infections (including duration of surgery, emergency, contaminated operations, and external cerebrospinal fluid drainage) were similar in the Neuro-Patch and pericranium groups. Deep wound infection rates in the Neuro-Patch and pericranium groups were 15 and 5%, respectively (P = 0.06), and cerebrospinal fluid leaks were significantly more frequent in the Neuro-Patch group (13 versus 1.6%, P < 0.05).

CONCLUSION

The results of our investigations show that Neuro-Patch raised the risk of wound infection, as do foreign materials implanted in the body. Synthetic dural grafts should be reserved for when autologous grafts are not sufficient or possible. An extensive prospective multicenter randomized trial is needed to confirm our results.

Duraplasty: our current experience

BACKGROUND

A large variety of biologic and artificial materials have been suggested as dural substitutes. However, no ideal material for dural repair in neurosurgical procedures has been identified. The authors report their experience with Tutoplast processed dura and pericardium.

METHODS

This study is designed to evaluate Tutoplast dura and pericardium. The study population was composed of 250 consecutive patients who underwent cerebral duraplasty with these homologous materials between 1996 and 1998. The average follow-up was 5.4 years.

RESULTS

We have observed only four complications with uncertain relationship with the dural implant. These resulted in complete recovery.

CONCLUSIONS

We support the efficacy and safety of this natural dural substitute treated with Tutoplast method.

Dural substitute for long-term imaging of cortical activity in behaving monkeys and its clinical implications

We present a transparent silicone dural substitute, which we have been using for the last 7 years for imaging cortical dynamics in awake behaving monkeys. This substitute enabled us to record optically for more than a year intrinsic or voltage sensitive dye signals. It is thin and elastic enough to allow microelectrode to pass through without any damage, using full visual control to target the electrode to the desirable recording site. This implant has proved crucial for maintaining the cortex in a good physiological condition and for preserving its optical characteristics that are necessary for optical imaging. We describe the details of the surgical implantation of the silicone dural substitute, the maintenance of the exposed cortex over long periods of time, the cortical reaction to this implant and its possible clinical implications in humans, and the rehabilitation procedure in monkeys.

Human dural replacement with acellular dermis: clinical results and a review of the literature

BACKGROUND

The search for the ideal dural replacement in the setting where autogenous tissues are unavailable or inadequate still persists. Because of the ability of acellular dermis (AlloDerm, LifeCell Corporation, The Woodlands, TX) to remodel itself into native tissue, this dynamic quality is hypothesized to occur when used as a dural replacement.

METHODS

We report the long-term outcome of a small cohort of patients who, to our knowledge, were the first patients to receive AlloDerm for dural replacement. In addition, to put these current findings in a historical perspective, we present a review of the literature for dural replacement.

RESULTS

Ten patients all successfully underwent duraplasty with AlloDerm with only one postoperative complication that was not related to the acellular dermal dural repair.

CONCLUSIONS

We contend that AlloDerm is a safe and viable option for dural replacement in cases in which autogenous tissues are either unavailable or insufficient for proper reconstruction.

Prevention of arachnoiditis and postoperative tethering of the spinal cord with Gore-Tex surgical membrane: an experimental study with rats

OBJECTIVE

Arachnoidal adhesions and inflammation were evaluated in 72 rats after spinal dural repair with one of three materials, i.e., Gore-Tex surgical membrane, collagen-coated Vicryl mesh, or lyophilized spinal dural allograft.

METHODS

Laminectomy at L1 was performed, and then a 3- x 4-mm segment of spinal dura mater and arachnoid membrane was excised. After implantation of the dural substitute, the animals were divided into normal and injured groups. In the injured group, a spinal cord injury was produced at the midpoint of the duraplasty site by the clip compression technique, with 25-g force for 1 minute. Neurological performance was assessed by the inclined plane technique, and groups of rats were killed at 8 to 24 weeks after surgery. The spinal column was removed en bloc and processed for histological examination.

RESULTS

There were no differences in neurological function among the three dural substitutes in either injured or noninjured rats. However, there were major differences among the groups in the incidence and severity of arachnoid adhesions and tethering. The neural tissue was bound to a thick neomembrane surrounding the lyophilized dural allograft and the collagen-coated Vicryl mesh. In contrast, the Gore-Tex surgical membrane induced only a thin membranous adhesion, which was loose and flexible. The inflammatory and foreign body response was most pronounced in rats treated with collagen-coated Vicryl mesh, at 8 and 24 weeks.

CONCLUSION

In the present study, Gore-Tex surgical membrane was a very good material for the surgical repair of spinal dural defects. Additional experimental studies are required to compare Gore-Tex membrane with autologous tissues.

Efficacy and biocompatibility of a photopolymerized, synthetic, absorbable hydrogel as a dural sealant in a canine craniotomy model

OBJECT

A canine craniotomy model was used to evaluate the dural sealing efficacy and biocompatibility of a novel, synthetic, bioresorbable hydrogel.

METHODS

Bilateral craniotomies were performed in 24 dogs assigned to six survival periods. In each animal a parasagittal durotomy was created and then repaired. At the treatment sites the hydrogel sealant was applied over the dural repair and photopolymerized. The repair was tested for leaks to 20 cm H2O by using a Valsalva maneuver. At the control sites the incisions were sutured and tested for leaks only. After uneventful survival periods, the leak test was repeated in three of the four animals in each group. Bone-dura adhesion was evaluated, after which the dura and underlying brain were removed, fixed, and examined histologically. En bloc histological investigation was performed on a specimen obtained from the fourth animal in each group. Over a 56-day period, 18 treated sites were tested for leaks. A leak was detected at a site remote from that of the repair in one animal; this was excluded from analysis. Thus 17 of 17 treated sites remained free of leaks. On the control side of one animal, there was a leak from a new dural tear at the cranial end of the durotomy, which occurred when the bone flap was removed. This site was also excluded from analysis. Eleven of 17 leak-tested control sites remained free of leaks over the study period. Bone-dura adhesions occurred in 15 of 19 control sites and had a mean adhesion score of 1.37 (range 0-4), whereas adhesions occurred in 10 of 19 treated sites with a mean adhesion score of 0.84 (range 0-3). No cortical reaction was noted.

CONCLUSIONS

This novel hydrogel sealant is efficacious in sealing dural repair sites measuring up to 2 mm. Healing of the underlying dura is not compromised and exposed cortical tissue is not altered histologically.

Delayed cervical epidural hemorrhage associated with silastic dural implant: case report

OBJECTIVE AND IMPORTANCE

This is the first report of delayed cervical epidural hemorrhage caused by an onlay silastic graft placed over the dura after laminectomy. There are several reports of intracranial hemorrhage associated with silastic implants in the literature.

CLINICAL PRESENTATION

A 49-year-old woman suddenly developed severe neck pain and quadriplegia during sexual intercourse. A C5-C7 laminectomy had been performed 17 years earlier for cervical stenosis.

INTERVENTION

Magnetic resonance imaging showed an epidural mass compressing the cord at the level of the previous laminectomy. Laminectomy was performed within 5 hours of symptom onset. Postoperatively, the patient regained leg strength. After 2 months of physical therapy, she had minimal residual leg rigidity and returned to work.

TECHNIQUE

At surgery, the cervical cord was compressed by a solid fibrous scar surrounding a silastic onlay graft and the dura. An epidural hematoma was beneath the silastic implant. The dense scar tissue, hematoma, and silastic implant were removed.

CONCLUSION

Bleeding associated with silastic sheets starts with movement of this nonadherent implant. The movement disrupts the underlying fine vessels on the surface of an encasing connective tissue membrane. Overgrowth of this membrane can cause mass effect and simulate a tumor, even without associated bleeding, within weeks. Delayed hemorrhage is more common. We recommend removal of these implants electively, especially if a thick membrane surrounding the dura is detected with postcontrast-enhanced magnetic resonance imaging.

Hemorrhagic complications in association with silastic dural substitute: pediatric and adult case reports with a review of the literature

OBJECTIVE AND IMPORTANCE

Delayed intracranial hemorrhage is an unusual complication associated with the use of silastic dural substitute.

CLINICAL PRESENTATION

We present three patients with this complication. Two adult patients developed subdural and epidural hemorrhages 9 months and 10 years after posterior fossa surgery for Chiari malformations. The remaining patient, a 13-month-old child, is the youngest reported patient to develop an epidural hematoma 8 months after a craniosynostosis repair.

INTERVENTION

The hematomas were removed with the silastic dural substitute from all three patients, and the dural defect was repaired with autologous paracervical fascia.

CONCLUSION

Silastic dural grafts have an increased incidence of hemorrhage associated with their use. A slight increase in the prevalence of hemorrhagic complications with silastic dural substitute was observed in women. We report our radiographic and surgical findings, including an extensive review of the literature.

The use of Vicryl Collagen as a dura substitute: a clinical review of 78 surgical cases

We performed a retrospective review of 78 consecutive neurosurgical procedures using Vicryl Collagen, a resorbable mesh of polyglactin 910 coated with bovine collagen, for dural substitution. The complications we encountered were infrequent and mostly minor (5 cases of subcutaneous CSF collections, 2 cases of aseptic meningitis, 1 superficial wound infection), and not unusual for the surgical procedures studied. One patient, however, had a major infection, starting in the superficial tissues, and extending toward the brain. In this patient, the resorption of the dural substitute appeared to be the cause for the intracranial extension of the infection. Three patients were reoperated on for recurrent tumour after a longer interval. We found minimal adhesions and good fibrous incorporation of the Vicryl Collagen into the surrounding normal dura. We conclude that Vicryl Collagen is a valuable alternative to the patient's own fibrous tissues when dural substitution is necessary.

Bovine pericardium for dural grafts: clinical results in 35 patients

OBJECTIVE

The United States Food and Drug Administration has recently approved the marketing of bovine pericardium as a dural graft material, but literature reports of this use are limited. Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report the use of glutaraldehyde-processed bovine pericardium for dural grafts in 35 patients undergoing cranial and craniospinal operations with the objective of providing a clinical assessment of this material and technique.

METHODS

This report is a retrospective analysis of 35 patients. All available records were reviewed and information regarding the indication for grafting, graft size, complications, and outcome were collected and analyzed for all patients.

RESULTS

Indications for grafting included meningioma resection, posterior fossa craniotomy, Chiari decompression, dural-based metastases, and trauma. Outcomes were good or excellent in 32 patients; the three fair or poor outcomes were not related to surgical closure. In no patient was the dural graft a significant factor in outcome. Bovine pericardium was found to be easily sutured to be watertight using standard suture material. The material is relatively inexpensive and requires no additional incision. It has low antigenicity and toxicity, good strength, and minimal elasticity.

CONCLUSION

In this clinical assessment, bovine pericardium was found to be an excellent dural graft material.