Gelatine Based “Bone Wax” (2010)

To the Editor: We have read with interest the paper by Magyar et al1 on a new alkylene oxide copolymer bone hemostatic material (Ostene) and we congratulate the authors for conducting a throughout study on a new water soluble bone hemostat. We fully agree with the authors of the abovementioned paper on the problems associated with the use of bone wax, including inhibition of osteogenesis, infection, foreign body response causing a giant cell reaction (“wax granuloma”), local inflammation, and pain. As a consequence, the use of bone wax is often avoided in spine procedures in which fusion is desirable. Although research into new hemostatic materials such as done by Magyar et al1 is important, we want to bring an alternative bone hemostat to the attention of the readers of Neurosurgery, called Geliputty (Gelitamedical BV, Hoofddorp, The Netherlands). This product consists of gelatine powder, that has to be mixed with physiological saline prior to its use, and dependent on how much saline is used, a more or less paste like substance is formed, although little bit softer that bone wax (Figure). This substance can be made into a mold and used in a standard manner to “plug” bleeding points in the bone.2 Due to its softer character, it is according to our experience easier in use that the traditional bone wax.FIGURE: The preparation of the GelliPutty. The galtin powder has to be mixed with physiological saline prior to its use, and dependent on how much saline is used, a more or less paste like substance is formed, that is little bit softer that bone wax.Because Geliputty is water soluble (as is Ostene), it does not remain at the site of application and is absorbed within weeks after surgery without a foreign body reaction and does not inhibit bone fusion. We have achieved good hemostasis (ie, comparable with that when using traditional bone wax) with this product both in cranial and spinal surgery without complications related to its use. Moreover, is our experience that this product does not hinder bone growth and therefore it is also used in spinal procedures such as cervical anterior discectomy in our department. The use of gelatin as an alternative for bone hemostasis has been mentioned by the authors in the introduction and discussion section of their paper, but we have the following comments on that: Every product has its complications and this also applies for gelatine based hemostats. In our opinion, its main risk is the associated swelling and as a consequence were are very caution to use it close to brain or spinal cord. However, when using this product as a hemostat pure for closing bleeding points in the bone, we think that it is safe and as a fact of matter we have not yet encountered a gelatine-related complication. The authors state that gelatin based hemostats interfere with bone healing and refer to the paper of Schonauer et al.3 However, when reading this reference,3 not a single evidence is provided that gelatin may interfere with bone healing, on the contrary, several papers are discussed in this paper stating that gelatin does not inhibit bone healing or osteogenesis: “Taheri and colleagues used powdered gelatin foam in over 300 anterior cervical procedures, applying it on the interbody drill hole during drilling. Follow-up X-ray films showed no differences concerning bone healing with the patients previously treated without Gelfoam paste.4 Weiss also used the same agent in anterior cervical fusions, achieving excellent results.5 Larocca and Macnub used gelatin foam sponge as a scaffolding for fibroblasts over a laminectomy site in dogs.6 Wilkinson and colleagues studied gelatin foam paste's effect on bone healing and osteogenesis in 1981.7 They evaluated either the hemostatic or osteogenic effects on surgical bone lesions in rabbits of both gelatin paste and bone wax. Thirty rabbits received four trephine craniotomies and four lumbar laminectomies, alternatively treated with either gelatin paste or bone wax. The mean intraoperative blood loss was similar in both groups. At 1 week postoperatively, histological examination of the fracture site showed no differences, but at 4 weeks only the gelatin-treated site specimens were satisfactorily processed with new bone formation and no foreign body reaction. At 6 weeks, the force required to fracture the bone at the trephination sites was similar for both groups. They concluded that gelatin foam paste is a good alternative to bone wax for the control of bone bleeding and that it seems not to impair bone healing.”7 Moreover, Magyar et al state in their paper that gelatine should not be used in a contaminated field. They refer to the paper of Schonauer et al3 but in this paper, the recommendation that gelatin should not be used in a contaminated field is just postulated without further references or evidence. Furthermore, it is logical that corpora aliena should not be used in a contaminated or infected field and this applies not only to gelatin but also for all other hemostats, maybe except for oxidized cellulosis. In conclusion, we are of opinion that gelatin based bone wax is a good alternative to traditional bone wax for bone hemostasis. Nevertheless, the authors are congratulated with their basic and well performed study of bone hemostats. Katrin Van Loock Mark Plazier Dirk De Ridder Tomas Menovsky Antwerp, Belgium