Transconjunctival approach to the infraorbital a cadaveric and clinical study
region:
V. Ilankovan Canniesburn
Hospital,
Bearsden,
Glasgow
SUMMARY. The surgical anatomy of the transconjunctival approach to the infraorbital region was studied using fresh cadaver dissection, histological examination and in the clinical situation. The existence of a periorbital envelope which separates the orbital fat from the orbital septum, and a potential postseptal space was noted. Reference to these anatomical features could not be found in the literature. The postseptal space was used to gain access to the infraorbital rim and the orbital floor. Wire and plate osteosynthesis of the infraorbital rim and exploration and reconstruction of the orbital floor were performed without fat herniation into the operative field. Access was adequate for these procedures and lower lid malposition was not observed as a postoperative complication. _
INTRODUCTION
A transconjunctival incision is one of the recognised approaches for access to the orbital floor and the infraorbital rim (Converse, 1973; Tessier, 1973). The advantages of using this technique are that it produces no visible scar and carries a low incidence of postoperative ectropion (Wray et al., 1977). Entropion of the lower lid has been described as the main postoperative complication. However, the most commonly stated criticism of this technique is the lack of access to the operative field (Holtman et al., 1981). A lateral canthotomy has been recommended by Converse et al. (1977) to overcome this problem. The lower lid is divided into the anterior, middle and posterior lamellae. These anatomic compartments can also be described as preseptal, septal, and postseptal regions. The anterior lamella includes skin, subcutaneous tissue, orbicularis ocuh muscle and suborbicularis fascia. The middle lamella includes the orbital septum and tarsal plate, while the posterior lamella comprises the palpebral conjunctiva, the lower lid retractors and the extension of the orbital fat (Fig. 1). The lower lid retractors course superiorly and anteriorly so that they bridge the posterior and middle lamellae. The retractors include the inferior tarsal muscle, also described as Muller’s muscle, and the extension of the capsulopalpebral fascia (Marks et al., 1989). There are two routes for reaching the orbital floor from a transconjunctival incision; the preseptal and the postseptal (Converse, 1973). In the former, the incision is made between the tarsal plate and the septum, and the dissection is directed anterior to the that damage to latter. It has been reported the septum can result in ectropion of the lower lid (Hanako et al., 1980). In the postseptal approach the
Fig. I - Anatomy oC the Lower lid-sagittal section demonstrating the normal relationships of the anterior. middle and posterior lamellae. Anterior Iamclla: skin. subcutaneous tissue. orhicularis oculi muscle. suhorhicularis fascia. Middle lamella: tarsal plate, orbital septum. Posterior lamella: palpehral conjunctiva. Muller’s muscle, capsulopalpehral I’avzia. orbital l’at.
dissection inevitably goes through the fat resulting in its herniation into the operating field. The object of this study was to examine the surgical anatomy of the transconjunctival approach, the histology of the inferior orbital region, and the clinical use of this procedure.
MATERIALS
AND METHODS
The study comprised 1 Fresh cadaver region; I69
three parts:
dissection
of the
infraorbital
170
2
3
British
Journal
of Oral
and Maxillofacial
Surgerv
Histological examination of sagittal sections the infraorbital region (cadaver through specimens); Clinical use of this technique in patients.
Cadaveric
dissection
Four fresh cadaver heads were used. The dissection was carried out on one side and sagittal sections were taken from the other side for histology. Every attempt was made during the cadaveric dissection to
simulate surgery in patients. A transconjunctival incision was made in the palpebral conjunctiva about 4 mm from the lid margin. A lateral or medial canthotomy was performed in the cadaver, in order to demonstrate the dissection plane. The Muller’s muscle and the capsulopalpebral fascial attachment were incised and the dissection proceeded postseptally in close proximity to the orbital septum to reach the infraorbital rim. During the dissection the orbital fat was not exposed and an envelope was noted (Figs 2A & B). When dissection along this plane reached the infraorbital rim, the periosteum
Fig. 2A & B-The cadaveric dissection - a medial canthotomy has been performed in order to demonstrate the dissection plane. (a) The tarsal plate and septum have been retracted and the presence of an orbital envelope noted. (b) When the orbital envelope was incised orbital fat herniated via the gap. TA - Tarsus. OS - Orbital septum. POB - Periorbital envelope. OF- Orbital fat.
Fig. 3- Photomicrograph of the lower lid and infraorbital region in sagittal section. (H & E. Original magnification x25.) BC - Bulbar conjunctiva. IRM - Inferior rectus muscle. PC - Palpebral conjunctiva. TA - Tarsal plate. mm - Muller’s muscle. cpf - Capsulopalpebral fascia. SK - Skin. POB - Periorbital envelope. OF- Orbital fat. OS - Orbital septum. OOM - Orbicularis oculi muscle. POS - Postseptal space. SOF- Suborbicularis fascia. PE - Periosteum. IOM - Inferior oblique muscle.
172
British
Journal
of Oral
and Maxillofacial
Surgery
Long tenotomy scissors were used for the postseptal dissection and again a space was noted between the fat envelope and the septum (Fig. 4). The transconjunctival incision was performed in 31 patients and the follow-up period was 3-9 months. In all but three patients the orbital fat was not visualised. In the three patients, although the postseptal space was identified, the initial trauma had caused damage to the orbital fat envelope resulting in fat herniation medially and laterally (Fig. 5A). The following examples demonstrate the clinical use of this approach.
1.
Exploration and repair of the orbital floor.
A 27-year-old man was hit by a cricket ball and sustained a blow-out fracture of the orbital floor. He did not wish to have an external scar. The floor was explored and repaired via a transconjunctival approach as previously described (Fig. 5A).
has been shown consistently in the four cadaveric dissections and in the clinical situation, and was confirmed by histological examination. This newly described space is very much a ‘potential space’ and meticulous surgical dissection is essential to avoid perforating the envelope. Long tenotomy scissors are an essential surgical tool. The periosteum, capsulopalpebral fascia, and conjunctiva are closed in layers using 6/O catgut sutures, with a buried continuous conjunctival suture to minimise postoperative irritation. This approach has also been used for onlay augmentation to areas below the orbital rim and zygomatic eminence. The access obtained using this approach in patients was adequate for surgical approach to the infraorbital rim and the floor. A repeat bleopharoplasty incision can be avoided in patients who have already had this approach to the infraorbital region. Lower lid malposition was not experienced as a postoperative complication in any of the patients. Acknowledgement
2.
Plate osteosynthesis of the infruorbital rim.
A 22-year-old prisoner sustained a fracture of the infraorbital rim (Henderson’s classification, type 6). The rim was reconstructed using a microplate and screws through a transconjunctival approach (Fig. 5B).
3.
Wire osteosynthesis of the infraorbitul rim.
A 22-year-old female was involved in a road traffic accident and sustained a comminuted fracture of the malar complex. The rim was approached through a transconjunctival incision and the segments were stabilised by direct wiring (Fig. 5C). A transcutaneous Kirschner wire was used for drilling holes in the bone.
4.
Removal of an alloplustic implant.
A 44-year-old man who underwent orbital floor via a blepharoplasty repair I8 months previously incision developed infection. He also had residual ectropion from the previous approach, and this was slowly resolving. The silastic implant was removed through a transconjunctival approach with no postoperative complication (Fig. 5D).
DISCUSSION The detailed surgical anatomy with associated histological data of the infraorbital region could not be found in the literature. This study was initiated after the consistent finding in patients of an orbital fat envelope. In these cases treated using the transconjunctival incision, the orbital fat envelope was not breached. The existence of a postseptal space
I wish to record my sincere thanks to Dr Showdon, Senior Lecturer. Department of Anatomy, University of Glasgow, for his assistance in the cadavcric dissection and histological examination. 1 also thank Mr Moos and Mr A. El-Attar. Consultant Oral Surgeons at Canniesburn Hospital. for their support and guidance while preparing this paper.
References Converse. J. M.. Firmin. F.. Wood-Smith, D. & Friedland. J. A. (1973). The conjunctival approach in orbital fractures. flusric und Reconstructive Surgery, 52,656. Converse, J. M., Smith, B. & Wood-Smith. D. (lY77). Reconstructive Plastic Surgery. vol. 2. 2nd Ed.. pp. 76X-770. Philadelphia: Saunders. Hamako. C. & Boyles. H. I. (1980). Lower eyelid retraction after blepharoplasty. American Journal of‘Ophthulmology, 89. 517. Holtmann, B.. Wray. R. C. & Little. A. G. (IYXI). A random&d comparison of four incisions for orbital fractures. fhtic and Reconstrucrive Surgery. 67. 731. Marks, M. W.. Argcnta. L. C.. Friedman. R. J. & Hall, J. D. (19x9). Conchal cartilage and composite grafts for correction of lower lid retraction. Plastic und Reconstructive Surgery. 83.62’) Tessier, P. ( lY7.3). The conjunctival approach to the orbital floor and maxilla in congenital malformation and trauma. Journul of‘Mu.dlo-Fad Surgery. I. 3. Wray. R. C.. Holtmann. B.. Ribaudo, J. M., Keiter, J. & Weeks. P. M. (lY77). A comparison of conjunctival and subciliary incisions for orbital fractures. British Journul of Plastic Surgery. 30. 142.
The Author V. llankuvan
FDSRCS,
FRCS
Registrar in Oral and Maxillofacial Canniesburn Hospital Bcarsden Glasgow G6I I01
Surgery
Correspondence and requests for offprints to Mr V. Ilankovan. Senior Registrar in Oral and Maxillofacial Surgery. Newcastle General Hospital, Westgatc Road. Newcastle-upon-Tyne NE4 hBE Paper received 6 November 1990 Accepted 2X February IYY I
Transconjunctival
was incised. Subperiosteal dissection orbital floor and the rim. Histological
exposed
the
examination
The specimens were decalcified in decalcifying solution for 8 h. They were dehydrated first in 70%
Fig. 4 - Tenotomy scissors in the postseptal space demonstrating
the orbital septum anteriorly and the orbital fat envelope posteriorly.
approach to the infraorbital
region
alcohol for 3 h, followed by 90% alcohol for another 3 h. They underwent three changes in absolute alcohol with 2% collodion for 24 h. Following this, they were then treated with 4% collodion in absolute alcohol for 24 h. The specimens subsequently underwent three changes in amyl acetate over 18 h. The prepared specimens were placed in molten wax for 6 h and this process was repeated for a further 6 h. The final wax change was performed under air vacuum (30 lb per sq in) and then the specimen was embedded. The slices were stained using haematoxylin & eosin and Morrison’s stains. The histology of the infraorbital region demonstrated somewhat different features to those described in Figure 1. In the postseptal compartment, an orbital fat envelope was noted and a space existed between this envelope and the orbital septum (Fig. 3). This can be called the ‘postseptal space’. The specimens from all four heads demonstrated the fat envelope which is formed of connective tissue. Clinical use
In patients, the palpebral conjunctiva was dissected towards the fornix and sutured to the upper eyelid.
Fig. 5-(A) Orbital floor repair via a transconjunctival incision using a silastic implant (the fat herniation is due to the initial trauma). (B) Orbital rim reconstruction via a transconjunctival incision using a microplate. (C) Reconstruction of the orbital rim using direct
wiring via a transconjunctival
171
incision. (D) Removal of a silastic implant via a transconjunctival
incision.
British Journal
of Oral and Maxillofacial
Surgery
(1991) 29, 17S175
A comparison of template bleeding time with mucosal petechiometry as a measure of the platelet function defect induced by aspirin M. McGurk,
R. C. W. Dinsdale
Department of Oral and Maxillofacial Surgery, Turner Dental School, Manchester and Department of Oral Surgery, Charles Clifford Dental Hospital, Sheffield
SUMMARY. The object of this study was to assess the value of mucosal petechiometry as a useful method of measuring the haemostatic defect induced by aspirin. The template bleeding time was done for comparison. The results indicated that mucosal petechiometry did not measure the haemostatic defect induced by aspirin and that aspirin-induced alterations in platelet function were not important in the development of petechiae in healthy subjects.
INTRODUCTION
Petechiae are small red or purple spots which range in size from pinpoint to pinhead and signify an extravasation of blood in a subepidermal position. They occur particularly in severe thrombocytopenia and are an established feature in a number of pathological conditions associated with disturbed platelet function. Attention has therefore been drawn to the possibility of using petechiometry as a clinical tool. Two basic methods of inducing petechiae have been devised: a positive pressure system where, for example, the venous pressure in an arm may be raised by obstructing the venous return using a pressure cuff; or alternatively, a system whereby a negative pressure is applied to a standardised area of surface epithelium by way of a suction cup. In both instances petechiae are induced and the varying counts can be used as indices for measurement. Kozam (1968) examined the use of the negative pressure system and extended its use to the oral mucosa because he found the thin non-keratinised surface suited to the technique, a fact confirmed by Stirrups & Dinsdale (1977). Petechiometry was used by Figures et al. (1980) to demonstrate the effects of ACTH on the microvasculature. An apparent increase in vascular strength occurred with rises in the serum cortisol level. Petechiometry is a quick non-invasive technique and its use in both a clinical and experimental setting is of interest; however, its application has not been fully established. The present study was undertaken to investigate petechiometry as an alternative method to the skin bleeding time in the assessment of a platelet defect such as that induced by aspirin.
males with no history of a bleeding disorder and an age range of 19-32 years. The study was approved by the Ethics Committee and the participants were required to give their consent. As a prerequisite to entering this study the participants refrained from taking aspirin for 1 month and alcohol for 48 h prior to commencing the investigation (Deykin et al., 1982). The petechial counts and template bleeding measurements were taken 12 h before and 12 h after the ingestion of 325 mg of aspirin and the results were then compared. The technique described by Stirrups & Dinsdale (1977) was used for the mucosal petechiometry and readings were taken immediately prior to template bleeding measurements. Each recorded count was an average of the readings at two sites, one on the upper and one on the contra-lateral side of the lower lip. The four sites (pre- and post-aspirin) were randomly allocated and each site used once only. A negative pressure of 300 mmHg was applied in each instance and maintained for a period of 1 min. The experimental technique used for template bleeding was that described by Mielke et al. (1969). In the present investigation, two bleeding sites were selected in each patient, one on either forearm. The sites were allocated in a random manner and used only once. At each site, two adjacent standardised incisions were made using an appropriate template. The average time taken for these two incisions to stop bleeding was recorded. All measurements were made by the same person who worked without recall or knowledge of earlier readings. With regard to bleeding time, the operator (MM) indicated the end point of the experiment, and another person recorded the time.
METHOD
RESULTS
The subjects in this investigation
The analysis of the results showed that the petechial
were 22 healthy 173
region:
V. Ilankovan Canniesburn
Hospital,
Bearsden,
Glasgow
SUMMARY. The surgical anatomy of the transconjunctival approach to the infraorbital region was studied using fresh cadaver dissection, histological examination and in the clinical situation. The existence of a periorbital envelope which separates the orbital fat from the orbital septum, and a potential postseptal space was noted. Reference to these anatomical features could not be found in the literature. The postseptal space was used to gain access to the infraorbital rim and the orbital floor. Wire and plate osteosynthesis of the infraorbital rim and exploration and reconstruction of the orbital floor were performed without fat herniation into the operative field. Access was adequate for these procedures and lower lid malposition was not observed as a postoperative complication. _
INTRODUCTION
A transconjunctival incision is one of the recognised approaches for access to the orbital floor and the infraorbital rim (Converse, 1973; Tessier, 1973). The advantages of using this technique are that it produces no visible scar and carries a low incidence of postoperative ectropion (Wray et al., 1977). Entropion of the lower lid has been described as the main postoperative complication. However, the most commonly stated criticism of this technique is the lack of access to the operative field (Holtman et al., 1981). A lateral canthotomy has been recommended by Converse et al. (1977) to overcome this problem. The lower lid is divided into the anterior, middle and posterior lamellae. These anatomic compartments can also be described as preseptal, septal, and postseptal regions. The anterior lamella includes skin, subcutaneous tissue, orbicularis ocuh muscle and suborbicularis fascia. The middle lamella includes the orbital septum and tarsal plate, while the posterior lamella comprises the palpebral conjunctiva, the lower lid retractors and the extension of the orbital fat (Fig. 1). The lower lid retractors course superiorly and anteriorly so that they bridge the posterior and middle lamellae. The retractors include the inferior tarsal muscle, also described as Muller’s muscle, and the extension of the capsulopalpebral fascia (Marks et al., 1989). There are two routes for reaching the orbital floor from a transconjunctival incision; the preseptal and the postseptal (Converse, 1973). In the former, the incision is made between the tarsal plate and the septum, and the dissection is directed anterior to the that damage to latter. It has been reported the septum can result in ectropion of the lower lid (Hanako et al., 1980). In the postseptal approach the
Fig. I - Anatomy oC the Lower lid-sagittal section demonstrating the normal relationships of the anterior. middle and posterior lamellae. Anterior Iamclla: skin. subcutaneous tissue. orhicularis oculi muscle. suhorhicularis fascia. Middle lamella: tarsal plate, orbital septum. Posterior lamella: palpehral conjunctiva. Muller’s muscle, capsulopalpehral I’avzia. orbital l’at.
dissection inevitably goes through the fat resulting in its herniation into the operating field. The object of this study was to examine the surgical anatomy of the transconjunctival approach, the histology of the inferior orbital region, and the clinical use of this procedure.
MATERIALS
AND METHODS
The study comprised 1 Fresh cadaver region; I69
three parts:
dissection
of the
infraorbital
170
2
3
British
Journal
of Oral
and Maxillofacial
Surgerv
Histological examination of sagittal sections the infraorbital region (cadaver through specimens); Clinical use of this technique in patients.
Cadaveric
dissection
Four fresh cadaver heads were used. The dissection was carried out on one side and sagittal sections were taken from the other side for histology. Every attempt was made during the cadaveric dissection to
simulate surgery in patients. A transconjunctival incision was made in the palpebral conjunctiva about 4 mm from the lid margin. A lateral or medial canthotomy was performed in the cadaver, in order to demonstrate the dissection plane. The Muller’s muscle and the capsulopalpebral fascial attachment were incised and the dissection proceeded postseptally in close proximity to the orbital septum to reach the infraorbital rim. During the dissection the orbital fat was not exposed and an envelope was noted (Figs 2A & B). When dissection along this plane reached the infraorbital rim, the periosteum
Fig. 2A & B-The cadaveric dissection - a medial canthotomy has been performed in order to demonstrate the dissection plane. (a) The tarsal plate and septum have been retracted and the presence of an orbital envelope noted. (b) When the orbital envelope was incised orbital fat herniated via the gap. TA - Tarsus. OS - Orbital septum. POB - Periorbital envelope. OF- Orbital fat.
Fig. 3- Photomicrograph of the lower lid and infraorbital region in sagittal section. (H & E. Original magnification x25.) BC - Bulbar conjunctiva. IRM - Inferior rectus muscle. PC - Palpebral conjunctiva. TA - Tarsal plate. mm - Muller’s muscle. cpf - Capsulopalpebral fascia. SK - Skin. POB - Periorbital envelope. OF- Orbital fat. OS - Orbital septum. OOM - Orbicularis oculi muscle. POS - Postseptal space. SOF- Suborbicularis fascia. PE - Periosteum. IOM - Inferior oblique muscle.
172
British
Journal
of Oral
and Maxillofacial
Surgery
Long tenotomy scissors were used for the postseptal dissection and again a space was noted between the fat envelope and the septum (Fig. 4). The transconjunctival incision was performed in 31 patients and the follow-up period was 3-9 months. In all but three patients the orbital fat was not visualised. In the three patients, although the postseptal space was identified, the initial trauma had caused damage to the orbital fat envelope resulting in fat herniation medially and laterally (Fig. 5A). The following examples demonstrate the clinical use of this approach.
1.
Exploration and repair of the orbital floor.
A 27-year-old man was hit by a cricket ball and sustained a blow-out fracture of the orbital floor. He did not wish to have an external scar. The floor was explored and repaired via a transconjunctival approach as previously described (Fig. 5A).
has been shown consistently in the four cadaveric dissections and in the clinical situation, and was confirmed by histological examination. This newly described space is very much a ‘potential space’ and meticulous surgical dissection is essential to avoid perforating the envelope. Long tenotomy scissors are an essential surgical tool. The periosteum, capsulopalpebral fascia, and conjunctiva are closed in layers using 6/O catgut sutures, with a buried continuous conjunctival suture to minimise postoperative irritation. This approach has also been used for onlay augmentation to areas below the orbital rim and zygomatic eminence. The access obtained using this approach in patients was adequate for surgical approach to the infraorbital rim and the floor. A repeat bleopharoplasty incision can be avoided in patients who have already had this approach to the infraorbital region. Lower lid malposition was not experienced as a postoperative complication in any of the patients. Acknowledgement
2.
Plate osteosynthesis of the infruorbital rim.
A 22-year-old prisoner sustained a fracture of the infraorbital rim (Henderson’s classification, type 6). The rim was reconstructed using a microplate and screws through a transconjunctival approach (Fig. 5B).
3.
Wire osteosynthesis of the infraorbitul rim.
A 22-year-old female was involved in a road traffic accident and sustained a comminuted fracture of the malar complex. The rim was approached through a transconjunctival incision and the segments were stabilised by direct wiring (Fig. 5C). A transcutaneous Kirschner wire was used for drilling holes in the bone.
4.
Removal of an alloplustic implant.
A 44-year-old man who underwent orbital floor via a blepharoplasty repair I8 months previously incision developed infection. He also had residual ectropion from the previous approach, and this was slowly resolving. The silastic implant was removed through a transconjunctival approach with no postoperative complication (Fig. 5D).
DISCUSSION The detailed surgical anatomy with associated histological data of the infraorbital region could not be found in the literature. This study was initiated after the consistent finding in patients of an orbital fat envelope. In these cases treated using the transconjunctival incision, the orbital fat envelope was not breached. The existence of a postseptal space
I wish to record my sincere thanks to Dr Showdon, Senior Lecturer. Department of Anatomy, University of Glasgow, for his assistance in the cadavcric dissection and histological examination. 1 also thank Mr Moos and Mr A. El-Attar. Consultant Oral Surgeons at Canniesburn Hospital. for their support and guidance while preparing this paper.
References Converse. J. M.. Firmin. F.. Wood-Smith, D. & Friedland. J. A. (1973). The conjunctival approach in orbital fractures. flusric und Reconstructive Surgery, 52,656. Converse, J. M., Smith, B. & Wood-Smith. D. (lY77). Reconstructive Plastic Surgery. vol. 2. 2nd Ed.. pp. 76X-770. Philadelphia: Saunders. Hamako. C. & Boyles. H. I. (1980). Lower eyelid retraction after blepharoplasty. American Journal of‘Ophthulmology, 89. 517. Holtmann, B.. Wray. R. C. & Little. A. G. (IYXI). A random&d comparison of four incisions for orbital fractures. fhtic and Reconstrucrive Surgery. 67. 731. Marks, M. W.. Argcnta. L. C.. Friedman. R. J. & Hall, J. D. (19x9). Conchal cartilage and composite grafts for correction of lower lid retraction. Plastic und Reconstructive Surgery. 83.62’) Tessier, P. ( lY7.3). The conjunctival approach to the orbital floor and maxilla in congenital malformation and trauma. Journul of‘Mu.dlo-Fad Surgery. I. 3. Wray. R. C.. Holtmann. B.. Ribaudo, J. M., Keiter, J. & Weeks. P. M. (lY77). A comparison of conjunctival and subciliary incisions for orbital fractures. British Journul of Plastic Surgery. 30. 142.
The Author V. llankuvan
FDSRCS,
FRCS
Registrar in Oral and Maxillofacial Canniesburn Hospital Bcarsden Glasgow G6I I01
Surgery
Correspondence and requests for offprints to Mr V. Ilankovan. Senior Registrar in Oral and Maxillofacial Surgery. Newcastle General Hospital, Westgatc Road. Newcastle-upon-Tyne NE4 hBE Paper received 6 November 1990 Accepted 2X February IYY I
Transconjunctival
was incised. Subperiosteal dissection orbital floor and the rim. Histological
exposed
the
examination
The specimens were decalcified in decalcifying solution for 8 h. They were dehydrated first in 70%
Fig. 4 - Tenotomy scissors in the postseptal space demonstrating
the orbital septum anteriorly and the orbital fat envelope posteriorly.
approach to the infraorbital
region
alcohol for 3 h, followed by 90% alcohol for another 3 h. They underwent three changes in absolute alcohol with 2% collodion for 24 h. Following this, they were then treated with 4% collodion in absolute alcohol for 24 h. The specimens subsequently underwent three changes in amyl acetate over 18 h. The prepared specimens were placed in molten wax for 6 h and this process was repeated for a further 6 h. The final wax change was performed under air vacuum (30 lb per sq in) and then the specimen was embedded. The slices were stained using haematoxylin & eosin and Morrison’s stains. The histology of the infraorbital region demonstrated somewhat different features to those described in Figure 1. In the postseptal compartment, an orbital fat envelope was noted and a space existed between this envelope and the orbital septum (Fig. 3). This can be called the ‘postseptal space’. The specimens from all four heads demonstrated the fat envelope which is formed of connective tissue. Clinical use
In patients, the palpebral conjunctiva was dissected towards the fornix and sutured to the upper eyelid.
Fig. 5-(A) Orbital floor repair via a transconjunctival incision using a silastic implant (the fat herniation is due to the initial trauma). (B) Orbital rim reconstruction via a transconjunctival incision using a microplate. (C) Reconstruction of the orbital rim using direct
wiring via a transconjunctival
171
incision. (D) Removal of a silastic implant via a transconjunctival
incision.
British Journal
of Oral and Maxillofacial
Surgery
(1991) 29, 17S175
A comparison of template bleeding time with mucosal petechiometry as a measure of the platelet function defect induced by aspirin M. McGurk,
R. C. W. Dinsdale
Department of Oral and Maxillofacial Surgery, Turner Dental School, Manchester and Department of Oral Surgery, Charles Clifford Dental Hospital, Sheffield
SUMMARY. The object of this study was to assess the value of mucosal petechiometry as a useful method of measuring the haemostatic defect induced by aspirin. The template bleeding time was done for comparison. The results indicated that mucosal petechiometry did not measure the haemostatic defect induced by aspirin and that aspirin-induced alterations in platelet function were not important in the development of petechiae in healthy subjects.
INTRODUCTION
Petechiae are small red or purple spots which range in size from pinpoint to pinhead and signify an extravasation of blood in a subepidermal position. They occur particularly in severe thrombocytopenia and are an established feature in a number of pathological conditions associated with disturbed platelet function. Attention has therefore been drawn to the possibility of using petechiometry as a clinical tool. Two basic methods of inducing petechiae have been devised: a positive pressure system where, for example, the venous pressure in an arm may be raised by obstructing the venous return using a pressure cuff; or alternatively, a system whereby a negative pressure is applied to a standardised area of surface epithelium by way of a suction cup. In both instances petechiae are induced and the varying counts can be used as indices for measurement. Kozam (1968) examined the use of the negative pressure system and extended its use to the oral mucosa because he found the thin non-keratinised surface suited to the technique, a fact confirmed by Stirrups & Dinsdale (1977). Petechiometry was used by Figures et al. (1980) to demonstrate the effects of ACTH on the microvasculature. An apparent increase in vascular strength occurred with rises in the serum cortisol level. Petechiometry is a quick non-invasive technique and its use in both a clinical and experimental setting is of interest; however, its application has not been fully established. The present study was undertaken to investigate petechiometry as an alternative method to the skin bleeding time in the assessment of a platelet defect such as that induced by aspirin.
males with no history of a bleeding disorder and an age range of 19-32 years. The study was approved by the Ethics Committee and the participants were required to give their consent. As a prerequisite to entering this study the participants refrained from taking aspirin for 1 month and alcohol for 48 h prior to commencing the investigation (Deykin et al., 1982). The petechial counts and template bleeding measurements were taken 12 h before and 12 h after the ingestion of 325 mg of aspirin and the results were then compared. The technique described by Stirrups & Dinsdale (1977) was used for the mucosal petechiometry and readings were taken immediately prior to template bleeding measurements. Each recorded count was an average of the readings at two sites, one on the upper and one on the contra-lateral side of the lower lip. The four sites (pre- and post-aspirin) were randomly allocated and each site used once only. A negative pressure of 300 mmHg was applied in each instance and maintained for a period of 1 min. The experimental technique used for template bleeding was that described by Mielke et al. (1969). In the present investigation, two bleeding sites were selected in each patient, one on either forearm. The sites were allocated in a random manner and used only once. At each site, two adjacent standardised incisions were made using an appropriate template. The average time taken for these two incisions to stop bleeding was recorded. All measurements were made by the same person who worked without recall or knowledge of earlier readings. With regard to bleeding time, the operator (MM) indicated the end point of the experiment, and another person recorded the time.
METHOD
RESULTS
The subjects in this investigation
The analysis of the results showed that the petechial
were 22 healthy 173
