Spontaneous haematoma as unusual complication of silastic dural substitute. Report of 2 cases

The Effect of Adding Modified Chitosan on the Strength Properties of Bacterial Cellulose for Clinical Applications

Currently, several materials for the closure of the dura mater (DM) defects are known. However, the long-term results of their usage reveal a number of disadvantages. The use of antibiotics and chitosan is one of the major trends in solving the problems associated with infectious after-operational complications. This work compares the mechanical properties of samples of bacterial nanocellulose (BNC) impregnated with Novochizol™ and vancomycin with native BNC and preserved and native human DM. An assessment of the possibility of controling the mechanical properties of these materials by changing their thickness has been performed by statistical analysis methods. A total of 80 specimens of comparable samples were investigated. During the analysis, the results obtained, the factor of Novochizol™ addition has provided a statistically significant impact on the strength properties (Fisher Criteria p-value 0.00509 for stress and 0.00112 for deformation). Moreover, a stronger relationship between the thickness of the samples and their ultimate load was shown: R2=0.236 for BNC + Novochizol™ + vancomycin, compared to R2=0.0405 for native BNC. Using factor analysis, it was possible to show a significant effect of modified chitosan (Novochizol™) on the ultimate stress (p-value = 0.005).

Local Tolerance and Biodegradability of a Novel Artificial Dura Mater Graft Following Implantation Onto a Dural Defect in Rabbits

Dura mater defects are a common problem following neurosurgery. Dural grafts are used to repair these defects; among them are biodegradable polymeric synthetic grafts. ArtiFascia is a novel synthetic and fibrous Dural graft, composed of poly(l-lactic-co-caprolactone acid) (PLCL) and poly(d-lactic-co-caprolactone acid). In this study, the biodegradability and local tolerance of ArtiFascia was evaluated in rabbits and compared with a bovine collagen matrix as a reference control. ArtiFascia implantation resulted in the formation of neo-dura at the site of implantation and recovery of the dural damage and the calvaria bone above. The implanted graft was completely absorbed after 12 months and the remaining macrophages were morphologically consistent with the anti-inflammatory M2-like phenotype, which contributes to tissue healing and are not pro-inflammatory. The site of the drilled skull bone had a continuous smooth surface, without exuberant tissue or inflammation and a newly formed trabecular bone formation indicated the healing process of the bone. These results support the local tolerability and biodegradability of ArtiFascia when used as a dural graft in rabbits. This study suggests that PLCL-based grafts including ArtiFascia are safe and effective to repair Rabbit Dura.

Epidural multi-slitted microporous non-absorbable patch in decompressive craniectomy to facilitate cranioplasty: a preliminary study

Developing a surgical plane between the temporalis muscle and the dura is the most technically challenging step when performing cranioplasty for post-decompressive craniectomy defects. The authors report a simple technique to demarcate this surgical plane by laying a multi-slitted, microporous polyesterurethane (MPU) patch during decompressive craniectomy. Specifically, they tried to avoid creating potential spaces around the patch, which is the inherent drawback of published anti-adhesive techniques. In 21 patients undergoing decompressive craniectomy, and in 11 of them subsequently undergoing cranioplasty, there was no wound related complications. During cranioplasty, no epidural fluid collection was found; the patch could be separated from the temporalis muscle and the dura with blunt dissection leaving the muscle intact. They conclude that their epidural MPU patch technique is a safe technique, and appears useful to facilitate cranioplasty by helping the surgeon in developing the surgical plane between the temporalis muscle and the dura during cranioplasty.

Experimental evaluation of new chitin-chitosan graft for duraplasty

Natural materials such as collagen and alginate have promising applications as dural graft substitutes. These materials are able to restore the dural defect and create optimal conditions for the development of connective tissue at the site of injury. A promising material for biomedical applications is chitosan-a linear polysaccharide obtained by the deacetylation of chitin. It has been found to be nontoxic, biodegradable, biofunctional and biocompatible in addition to having antimicrobial characteristics. In this study we designed new chitin-chitosan substitutes for dura mater closure and evaluated their effectiveness and safety. Chitosan films were produced from 3 % of chitosan (molar mass-200, 500 or 700 kDa, deacetylation rate 80-90%) with addition of 20% of chitin. Antimicrobial effictively and cell viability were analysed for the different molar masses of chitosan. The film containing chitosan of molar mass 200 kDa, had the best antimicrobial and biological activity and was successfully used for experimental duraplasty in an in vivo model. In conclusion the chitin-chitosan membrane designed here met the requirements for a dura matter graft exhibiting the ability to support cell growth, inhibit microbial growth and biodegradade at an appropriate rate. Therefore this is a promising material for clinical duroplasty.

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.

Duraplasty using autologous fascia lata reenforced by on-site pedicled muscle flap: technical note

OBJECTIVE

Postoperative cerebrospinal fluid (CSF) leak is a common complication in the practice of neurosurgery, and various surgical techniques were described to overcome and manage this problem. Besides not applying watertight closure of the duraplasty, the inviability and the poor vascularization of the graft and/or the dura (eg, reoperations, multiple operations, or cranial radiotherapy) may lead to delayed healing of the suture site and resultant persistent CSF leaks. We present a simple technique that uses on-site muscle flap with pedicle to supply and vascularize the autologous fascia lata, preserving the viability of the graft and reenforcing its healing ability.

METHODS

We applied this technique in 6 patients with postoperative CSF leaks. After harvesting a fascia lata graft with appropriate size from the patients, the graft was sutured to dural defect in watertight fashion. The suboccipital, temporal, and temporal muscles in 4 patients who had posterior fossa duraplasty, in 1 patient who had pterional craniotomy, and in 1 patient who had subtemporal craniotomy, respectively, were dissected, stretched, and sutured to the fascia graft covering the dura graft suture site and then reinforced by Tisseel fibrin glue (Baxter Healthcare Corporation, Deerfield, IL). Postoperatively, CSF lumbar drain was kept open for 72 hours with pressure wound dressing. The technical nuances are illustrated.

RESULTS

Cerebrospinal fluid leaks were controlled successfully in 5 patients without recurrence. One patient with posterior fossa duraplasty had recurrence of CSF leak that required reexploration 21 days after the first surgery and a second dural repair in a site distant from the fascia lata attachment. During reexploration intraoperatively, the fascia lata graft was inspected and studied, which has shown the healing of the dura graft site and the graft neovascularization.

CONCLUSIONS

Duraplasty using autologous fascia lata reenforced by on-site pedicled muscle flap is an effective technique to control CSF leak, especially when dura is poorly vascularized and less viable. The unfortunate recurrence of CSF leak and reexploration in the seventh patient helped us to observe the effectively healed dural defect with profound early postoperative vascularization of the graft, supporting our idea about the effectiveness of this technique.

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.

Usefulness of acellular dermal graft as a dural substitute in experimental model

BACKGROUND

Friction injury of cortical surface or cerebrospinal fluid leakage are the major complications of polytetrafluoroethylene (ePTFE) duraplasty because of their strong surface tension and lesser adaptability. Autologous duraplasties are also accompanied by potential donor-site complications and are inappropriate for large defects. Acellular Dermal Graft (ADG), prepared from cadaver human skin, does not have the above-mentioned drawbacks because of its human nature. Moreover, the dermal basement membrane and supporting tissues remain intact, so the rate of cellular migration and transformation to the surrounding host tissue is supposed to be excellent. We studied ADG in canine model to observe the rate of transformation into the surrounding dura mater via collagen synthesis from the invaded fibroblasts to evaluate its usefulness as a duraplasty.

METHODS

Dural grafting surgery was performed on 6 adult mongrel dogs weighing from 8 to 12 kgs under general anesthesia. Three dogs were sacrificed after 1 month (acute) of surgery and the other three (chronic) were sacrificed after 3 months with overdose of pentobarbital sodium. Transcardiac perfusion-fixation with 4% paraformaldehyde was done. Hematoxylin-eosin and trichrome masson stains were performed to see the graft cellularity. Thickness of grafts was also assessed along the length of the histologic sections.

RESULTS

Duralization, which was microscopically characterized by infiltration with regular array of collagen fibers, was observed at a few places in every high-power field in acute group. But in chronic animals, where dermal side of ADG was facing towards cranium, duralization was excellent.

CONCLUSIONS

Our result suggests that ADG can be considered as a useful dural substitute.

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.

Tightness of duraplasty in rabbits: a comparative study

OBJECTIVE

The purpose of this study was to test, in rabbits, the tightness of seven dural substitution materials commonly used in neurosurgery, i.e., Lyodura (B. Braun Melsungen AG, Melsungen, Germany), Tutoplast dura (Tutogen Medical, Inc., Parsippany, NJ), Tutoplast fascia lata (Tutogen Medical, Inc.), autologous periosteum, Neuropatch (B. Braun Melsungen AG), Dacron (E.I. du Pont de Nemours and Co., Wilmington, DE), and Ethisorb (Ethicon, Inc., Somerville, NJ).

METHODS

Duraplasties were performed with sutures alone or were additionally fixed with fibrin glue. Leakage pressures were assessed by infusion of artificial cerebrospinal fluid, containing sodium fluorescein, into the cisterna magna and detection of fluorescence using a charge-coupled display camera with background substraction, 3 days, 3 weeks, or 3 months after surgery.

RESULTS

Three days after implantation, the mean tightness values of duraplasties with Lyodura or Neuropatch were significantly higher (P = 0.007) than the values for the other substitutes. A significant improvement of tightness with increasing implantation time could be demonstrated for autologous periosteum (P = 0.0063). Improvement of tightness with the use of fibrin glue could be proven only for the heterologous grafts (P = 0.0071). The tightness values for Neuropatch fixed only with sutures were similar to those for the best heterologous substitutes implanted with additional fibrin glue. Lyodura, Tutoplast dura, and Neuropatch demonstrated favorable implantation characteristics; they were thin, flexible, and easily suturable. Neither adhesions to the brain nor space-occupying scars were noted.

CONCLUSION

These results confirm the excellent suitability of Lyodura and Neuropatch for dural substitution.

Dural closure with nonpenetrating clips prevents meningoneural adhesions: an experimental study in dogs

OBJECTIVE

Meningospinal and cranial dural adhesions were compared in a canine model, after duraplasty using nonpenetrating clips or penetrating needles and sutures.

METHODS

Fourteen dogs underwent bilateral craniotomies and duraplasties, with implantation of dural prostheses (DuraGuard; Biovascular Corp., Minneapolis, MN), using either 6-0 silk sutures or titanium clips (DuraClose; Surgical Dynamics, Norwalk, CT). Fourteen other dogs underwent L3-L4 laminectomies; three longitudinal dural incisions were closed with 6-0 silk sutures, 6-0 polyglactin 910 (Vicryl) sutures, or clips. Groups of eight dogs (four cranially treated and four spinally treated) were killed 6, 12, 24, and 52 weeks after surgery, and specimens were collected for study after perfusion and fixation (two cranial and two spinal dural reconstructions at 52 wk). Evaluations included assessment of the appearance of approximated dural margins and responses to clips, sutures, and dural prostheses (inflammation, foreign body reaction, fibrosis, and severity of meningospinal/meningocerebral adhesions). Data were evaluated using the Wilcoxon signed-rank and McNemar tests.

RESULTS

Duraplasties with clips displayed significantly less extensive acute and chronic inflammation, foreign body reaction, and meningoneural adhesions than did repairs with needles and sutures.

CONCLUSION

This report is the first long-term experimental study comparing two fundamentally different methods for dural repair in a relevant animal model.

Late complications of Silastic duraplasty: low-virulence infections. Case report

The authors describe three patients with expanding hemorrhagic mass lesions who presented 13 to 18 years after undergoing Silastic duraplasty. In all patients, results of bacteriological cultures of the masses obtained intraoperatively were positive, revealing low-virulence bacteria. Two of the patients were treated with antibiotic drugs and made a good recovery. The third did not receive antibiotic medications initially and later developed an epidural empyema that necessitated reoperation, but subsequently made a complete recovery. Vascularized neomembranes are generally agreed to be causes of the expanding masses, but the possibility that patients could be harboring chronic infections must be considered. Thus, on removal of duraplasty materials a complete bacteriological culture should be obtained, and if it is positive the proper antibiotic therapy should be administered. Furthermore, the creation of a registry of patients who have received implants is advocated to facilitate tracking of implanted material in case of complications.

The immunopathology of siliconosis. History, clinical presentation, and relation to silicosis and the chemistry of silicon and silicone

Recent evidence confirms the fundamental involvement of the human immune system in the reaction to implantation of silicone-based medical devices. An as yet-to-be particularized epitope of many complex substances sharing siloxane structures is presented through the MHC-II apparatus with development and retention of T cell memory. This memory can be tested for in practical terms using one or more forms of silica, which links the immuno-histopathology and autoimmune attributes of "silicosis" with those of "siliconosis." The lesions of siliconosis are typical of those for persistent antigens and delayed, cell mediated hypersensitivity. The basic descriptive pathology of the reaction to silicone has been known since soon after introduction of silicones in medical procedures, with the exception of some details related to the more recent discoveries on the role of cytokines in the immunopathic process. The clinical consequences of siliconosis are common and can be severe in some individuals implanted with silicone devices.

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.

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.

Fibrotic-haemorrhagic reaction to synthetic dural substitute

A case is presented in which a patient developed a complication related to the use of Silastic dural substitute. Ten years after the initial surgery, a fibrotic-haemorrhagic reaction around the graft material was found, mimicking a recurrent meningioma clinically and radiologically. A review of the literature and suggested mechanisms of these complications are reported.

Haemorrhage associated with silastic dural substitute

Three cases of haemorrhage after the use of a silastic dural substitute are presented. In all cases the implant was removed and further haemorrhage has not occurred. Published work is reviewed and the implications for the continued use of silastic are discussed.