Original Investigation
Effect of Orbital Decompression on Diplopia in Thyroid-Related Orbitopathy Norman P. Mainville, M.D.*, and David R. Jordan, M.D.† *Department of Ophthalmology, Sudbury Regional Hospital, Sudbury; and †Department of Ophthalmology, University of Ottawa Eye Institute and The Ottawa Hospital, Ottawa, Ontario, Canada
Purpose: To determine the incidence of new-onset diplopia and evolution of preexisting diplopia in patients with thyroidrelated orbitopathy undergoing orbital decompression surgery. Methods: A retrospective chart review was conducted of patients who had undergone orbital decompression for thyroidrelated orbitopathy between 1999 and 2008 in one of the authors’ practice (D.J.). A total of 217 orbits in 123 patients were identified. The clinical indication for decompression surgery (i.e., exposure keratitis, optic neuropathy, or improvement of cosmesis) was recorded in each case, as was the presence of pre- and postoperative diplopia. The surgical technique (1-, 2-, or 3-wall decompression) was noted for each patient. Results: Review of the charts of patients who underwent orbital decompression surgery for thyroid-related orbitopathy revealed a preoperative prevalence of diplopia of 26% and a postoperative prevalence of 40.7%. Amongst the patients with preoperative diplopia (n = 32), 28.1% (n = 9) had complete resolution of their diplopia after decompression, while 65.6% (n = 21) remained stable and 6.3% (n = 2) worsened. The incidence of new-onset diplopia was 29.7% in this case series of orbital decompression using a transcaruncular and swinging eyelid approach for medial wall and strut-sparing floor decompression. Rates of new-onset diplopia were significantly higher when periorbita was opened (40.0%, n = 82) compared with when it was left intact (11.8%, n = 37) Conclusions: It has previously been reported in the literature that orbital decompression for thyroid-related orbitopathy can cause diplopia in a significant number of cases. This provides the rational for performing orbital decompression prior to strabismus surgery in the management of thyroid-related orbitopathy. In this case series, the authors noted resolution of diplopia in a significant proportion (28.1%) of patients with preexisting diplopia. This is rarely commented on in other articles but is important in the preoperative discussion. An incidence of new-onset diplopia of 29.7% was identified. Opening the periorbita was associated with an increased incidence of new-onset diplopia. (Ophthal Plast Reconstr Surg 2014;30:137–140)
G
raves disease can lead to a multitude of ophthalmic manifestations including eyelid retraction, proptosis, keratitis, chemosis, motility disturbances with diplopia and optic
Accepted for publication August 31, 2013. The authors have no financial or conflicts of interest to disclose. Address correspondence and reprint requests to David R. Jordan, M.D., Department of Ophthalmology, University of Ottawa Eye Institute and The Ottawa Hospital, 301 O’Connor St., Ottawa, Ontario, Canada. E-mail: [email protected] DOI: 10.1097/IOP.0000000000000029
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
neuropathy.1 Although corticosteroids and radiation therapy have a role in the management of thyroid-related orbitopathy in the inflammatory phase, orbital decompression remains the mainstay of therapy in cases with optic neuropathy refractory to steroids, exposure keratopathy, and in improving cosmesis in the postinflammatory phase of the disease.2 Various techniques for orbital decompression have been described in the literature. These include various combinations of medial wall, floor, or lateral wall bone removal with or without orbital fat removal. Certain authors have even reported satisfactory results in decompression by removal of orbital fat alone without any bony removal.3 However, to achieve adequate reduction in proptosis or relief of optic nerve compression, most surgeons will perform some bony removal as part of their decompression. All strategies for orbital decompression have their own risks and limitations. Lateral wall decompressions have increased risk of cerebrospinal fluid (CSF) leaks and inducing pulsatile proptosis while at the same time having a limited potential for volume augmentation.4–6 Orbital floor decompressions have a higher risk of inducing hypoglobus and hypoesthesia of the infraorbital nerve, while medial wall decompressions have a higher risk of CSF rhinorrhea.7 In an effort to reduce the risk of postoperative strabismus, some authors advocated the use of “balanced decompressions” in which medial and lateral wall decompressions are performed or deep lateral wall bony removal alone with or without fat removal.8,9 These techniques have been reported as being less likely to induce strabismus and diplopia than medial and inferior decompression techniques with rates of new-onset strabismus of 7% and 33%,10 respectively, compared with rates 13% to 80% reported for combination floor/medial wall decompressions depending on the technique used. Additional techniques proposed to minimize postoperative diplopia include preservation of the inferomedial orbital strut to prevent inferomedial displacement of the orbital contents11 as well a judicious opening of the periorbita along the medial wall, leaving a horizontal strip intact overlying the medial rectus muscle.12 Resolution of diplopia with orbital decompression is seldom reported, but it is an important variable to consider when discussing orbital decompression with the patient preoperatively. In this study, a retrospective chart review was conducted of 128 patients who had undergone orbital decompression for thyroid-related orbitopathy between 1999 and 2008. A total of 123 patients (217 orbits) were included in this study; the other 5 patients were excluded from the analysis because of incomplete chart data. The incidence of new-onset diplopia and evolution of preexisting diplopia in this patient group is reported.
MATERIALS AND METHODS A retrospective chart review of all patients undergoing orbital decompression in 1 author’s practice (D.J.) for thyroid-related orbitopathy
137
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
N. P. Mainville and D. R. Jordan
between 1999 and 2008 was performed. Ethics approval for this study was provided by the Research Ethics Committee of the University of Ottawa. The following data were collected from clinical charts: age, gender, indication for surgery, use of preoperative steroid treatment, pre- and postoperative visual acuity, hertel exophthalmometry measurements, diplopia, palpebral fissure height, unilateral versus bilateral decompression, decompression technique, fat volume removed, integrity of the periorbita, and follow-up duration. The presence or absence of diplopia was based on subjective reporting by the patient at the time of the final follow-up visit and was considered to be present if any form of diplopia was reported, including intermittent and gaze-evoked and diplopia in primary or downgaze. Orthoptic assessments were not performed as they were extremely difficult to obtain in the primary author’s city with limited capacity and lengthy waiting times. A total of 128 patient charts were reviewed. Of these, 123 charts had complete information regarding pre and postoperative diplopia and strabismus and were included in the analysis. Surgical Technique. All orbital decompressions were performed under general anesthesia. The lateral canthal area and inferior fornix were infiltrated with approximately 2.5 ml of 2% xylocaine with epinephrine 1:100,000 mixed 50/50 with bacteriostatic saline. The nasal mucosa was packed with neuro patties soaked in 4% cocaine. A lateral canthotomy and inferior cantholysis were performed followed by incision of the conjunctiva and lower eyelid retractors at the inferior border of the tarsal plate across its entire width. Blunt dissection was carried out in a preseptal plane down to the inferior orbital rim. The periorbita was incised at the rim and using blunt dissection was elevated from the floor of the orbit. The portion of the floor medial to the infraorbital canal was removed with preservation of the anterior 10 mm of the floor behind the rim. The inferomedial bony strut at the junction of the ethmoid and maxillary sinuses were also preserved (3–4 mm average width remaining). Periorbita in the area overlying the defect in the floor was usually left intact. The medial wall of the orbit was accessed via a transcaruncular incision. Periorbita was elevated from the medial wall. Anterior and posterior ethmoidal vessels were cauterized. Bone was removed to a level approximately 4 to 5 mm beyond the posterior ethmoidal vessel with preservation of 1 mm of bone below the level of the ethmoidal vessels and 10 mm of bone behind the orbital rim. If indicated, periorbita overlying the medial osteotomy and parallel to medial rectus (i.e., from approximately 4 to 5 mm beyond the posterior ethmoidal artery to 10 mm posterior to the orbital rim) was opened using a no. 12 blade to allow protrusion of the medial rectus and medial orbital tissue in the ethmoid sinus. Orbital fat removal was performed in the inferolateral aspect of the orbit by opening the periorbita between inferior rectus and lateral rectus and removing between 1 and 4 cm3 of intraconal fat. The transcaruncular incision and infratarsal incisions were closed with 7-0 chromic suture. The lateral canthal tendon was reapproximated with 4-0 vicryl suture. Postoperative Care. Patients were administered intraoperative doses of 8 to 16 mg of decadron intravenously. Postoperatively, they were given oral prednisone starting at 60 mg and tapering by 10 mg daily. Topical and systemic antibiotics were also prescribed. Follow-up visits were arranged at 1 week, 1, 3, and 6 months postoperatively. Statistical Analysis. A 2 × 2 analysis of variance (ANOVA) was performed with Surgical status (Pre vs. Post) and Eye (Right vs. Left) as within-subject variables on all observations. A 2 × 2 × 2 ANOVA was conducted on Hertel scores with Approach (intact vs. opened) as a between-subject factor, and Surgical Status (Pre vs. Post) and Eye (Right vs. Left) as within-subject variables. Chi-square with Yates correction was used to evaluate the significance of pre- and postoperative diplopia in patients who underwent 2-walled decompression with preservation versus opening of the periorbita.
138
RESULTS Women composed 74.0% of patients who underwent orbital decompression in this study. Mean age amongst women was 46.3 years (range 14–79 years) compared with men was 49.1 years (range of 17–82 years). Orbital decompression surgery was more commonly performed to improve cosmesis in women compared with men (76.9% vs 50.0%) (see Table 1). In contrast, decompression was performed more frequently in men compared with women (31.2% vs 11.0%) for optic neuropathy. This finding is consistent with previous reports that optic neuropathy more commonly affects men than women.13 Exposure keratitis was the indication for decompression in 18.8% of men versus 12.1% of women. Diplopia associated with restricted ocular motility was observed preoperatively in 26% of patients (n = 123 patients). The presence of postoperative diplopia was determined based on the patient’s reported symptoms at the time of their last clinical visit. Average follow-up duration was 19.2 months, while median follow-up duration was 10 months with a range of 1 to 90 months. Resolution of diplopia after surgery was observed in 9 of 32 patients (28.1%) patients. Postoperative prevalence of diplopia was 40.7%, with an incidence of new-onset diplopia in 29.7% of patients undergoing decompression surgery. These results are presented in Table 2. Almost all patients underwent decompression using a 2- or 3-wall decompression technique (Table 3). Given the limited number of 3-wall decompressions performed, further analysis was confined to the group of patients who underwent 2-wall decompression (n = 119). When patients are compared as to whether the periorbita was opened or left intact, the results of this study suggest that the former were more likely to have new-onset diplopia in the postoperative period. These results are summarized in Table 4. Pre- and postdecompression hertel measurements were recorded. Data from patients who underwent 2-wall decompression are summarized in Table 5. Data from the 1- and 3-wall decompressions are not presented because of the limited patient numbers in each group. Amongst all patients who underwent 2-wall decompression, there was a mean reduction
TABLE 1. Indication for decompression surgery Surgical indication Neuropathy Exposure keratitis Cosmesis
No. Overall cases percentage 20 17 86
16.3 13.8 69.9
Males (%)
Females (%)
31.2 (n = 10) 11.0 (n = 10) 18.8 (n = 6) 12.1 (n = 11) 50.0 (n = 16) 76.9 (n = 70)
n = 123.
TABLE 2. Diplopia prevalence and incidence Diplopia Preoperative Postoperative New-onset Resolved
No. cases
Percentage
32 50 27 9
26.0 (32/123) 40.7 (50/123) 29.7 (27/91) 28.1 (9/32)
n = 123.
TABLE 3. Effect of orbital decompression technique on diplopia Decompression No. Preoperative New-onset technique performed diplopia diplopia Resolution Single wall 2-walls 3-walls
1 119 3
0 30 2
0 26 1
0 9 0
n = 123.
© 2014 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
Effect of Orbital Decompression on Diplopia in Thyroid-Related Orbitopathy
TABLE 4. Effect of preservation versus incision of periobita on diplopia in 2-wall decompressions Decompression No. Preoperative New-onset technique performed diplopia diplopia Resolution Periorbita opened Periorbital intact
82
27
22
7
37
3
4
2
n = 119.
in hertel measurements of 3.07 mm. In those patients in whom the integrity of the periorbita was maintained, a mean reduction in hertel measurements of 2.90 mm was observed compared with those in whom the periorbita along the medial wall, floor, or both was opened, where a mean reduction of 3.12 mm was observed. Further analysis of those in whom the periorbita was opened revealed reductions of 2.94, 1.75, and 4.69 mm in hertel measurements postoperatively when periorbita along the medial wall only, floor only, or medial wall and floor was opened respectively. A 2 × 2 ANOVA was performed with surgical status (Pre vs. Post) and surgical site (Right vs. Left) as within-subject variables on all observations. Irrespective of technique, all patients improved about their Hertel scores, F (1, 104) = 263.05, mean squared error (MSe) = 3.75, p
Effect of Orbital Decompression on Diplopia in Thyroid-Related Orbitopathy Norman P. Mainville, M.D.*, and David R. Jordan, M.D.† *Department of Ophthalmology, Sudbury Regional Hospital, Sudbury; and †Department of Ophthalmology, University of Ottawa Eye Institute and The Ottawa Hospital, Ottawa, Ontario, Canada
Purpose: To determine the incidence of new-onset diplopia and evolution of preexisting diplopia in patients with thyroidrelated orbitopathy undergoing orbital decompression surgery. Methods: A retrospective chart review was conducted of patients who had undergone orbital decompression for thyroidrelated orbitopathy between 1999 and 2008 in one of the authors’ practice (D.J.). A total of 217 orbits in 123 patients were identified. The clinical indication for decompression surgery (i.e., exposure keratitis, optic neuropathy, or improvement of cosmesis) was recorded in each case, as was the presence of pre- and postoperative diplopia. The surgical technique (1-, 2-, or 3-wall decompression) was noted for each patient. Results: Review of the charts of patients who underwent orbital decompression surgery for thyroid-related orbitopathy revealed a preoperative prevalence of diplopia of 26% and a postoperative prevalence of 40.7%. Amongst the patients with preoperative diplopia (n = 32), 28.1% (n = 9) had complete resolution of their diplopia after decompression, while 65.6% (n = 21) remained stable and 6.3% (n = 2) worsened. The incidence of new-onset diplopia was 29.7% in this case series of orbital decompression using a transcaruncular and swinging eyelid approach for medial wall and strut-sparing floor decompression. Rates of new-onset diplopia were significantly higher when periorbita was opened (40.0%, n = 82) compared with when it was left intact (11.8%, n = 37) Conclusions: It has previously been reported in the literature that orbital decompression for thyroid-related orbitopathy can cause diplopia in a significant number of cases. This provides the rational for performing orbital decompression prior to strabismus surgery in the management of thyroid-related orbitopathy. In this case series, the authors noted resolution of diplopia in a significant proportion (28.1%) of patients with preexisting diplopia. This is rarely commented on in other articles but is important in the preoperative discussion. An incidence of new-onset diplopia of 29.7% was identified. Opening the periorbita was associated with an increased incidence of new-onset diplopia. (Ophthal Plast Reconstr Surg 2014;30:137–140)
G
raves disease can lead to a multitude of ophthalmic manifestations including eyelid retraction, proptosis, keratitis, chemosis, motility disturbances with diplopia and optic
Accepted for publication August 31, 2013. The authors have no financial or conflicts of interest to disclose. Address correspondence and reprint requests to David R. Jordan, M.D., Department of Ophthalmology, University of Ottawa Eye Institute and The Ottawa Hospital, 301 O’Connor St., Ottawa, Ontario, Canada. E-mail: [email protected] DOI: 10.1097/IOP.0000000000000029
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
neuropathy.1 Although corticosteroids and radiation therapy have a role in the management of thyroid-related orbitopathy in the inflammatory phase, orbital decompression remains the mainstay of therapy in cases with optic neuropathy refractory to steroids, exposure keratopathy, and in improving cosmesis in the postinflammatory phase of the disease.2 Various techniques for orbital decompression have been described in the literature. These include various combinations of medial wall, floor, or lateral wall bone removal with or without orbital fat removal. Certain authors have even reported satisfactory results in decompression by removal of orbital fat alone without any bony removal.3 However, to achieve adequate reduction in proptosis or relief of optic nerve compression, most surgeons will perform some bony removal as part of their decompression. All strategies for orbital decompression have their own risks and limitations. Lateral wall decompressions have increased risk of cerebrospinal fluid (CSF) leaks and inducing pulsatile proptosis while at the same time having a limited potential for volume augmentation.4–6 Orbital floor decompressions have a higher risk of inducing hypoglobus and hypoesthesia of the infraorbital nerve, while medial wall decompressions have a higher risk of CSF rhinorrhea.7 In an effort to reduce the risk of postoperative strabismus, some authors advocated the use of “balanced decompressions” in which medial and lateral wall decompressions are performed or deep lateral wall bony removal alone with or without fat removal.8,9 These techniques have been reported as being less likely to induce strabismus and diplopia than medial and inferior decompression techniques with rates of new-onset strabismus of 7% and 33%,10 respectively, compared with rates 13% to 80% reported for combination floor/medial wall decompressions depending on the technique used. Additional techniques proposed to minimize postoperative diplopia include preservation of the inferomedial orbital strut to prevent inferomedial displacement of the orbital contents11 as well a judicious opening of the periorbita along the medial wall, leaving a horizontal strip intact overlying the medial rectus muscle.12 Resolution of diplopia with orbital decompression is seldom reported, but it is an important variable to consider when discussing orbital decompression with the patient preoperatively. In this study, a retrospective chart review was conducted of 128 patients who had undergone orbital decompression for thyroid-related orbitopathy between 1999 and 2008. A total of 123 patients (217 orbits) were included in this study; the other 5 patients were excluded from the analysis because of incomplete chart data. The incidence of new-onset diplopia and evolution of preexisting diplopia in this patient group is reported.
MATERIALS AND METHODS A retrospective chart review of all patients undergoing orbital decompression in 1 author’s practice (D.J.) for thyroid-related orbitopathy
137
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
N. P. Mainville and D. R. Jordan
between 1999 and 2008 was performed. Ethics approval for this study was provided by the Research Ethics Committee of the University of Ottawa. The following data were collected from clinical charts: age, gender, indication for surgery, use of preoperative steroid treatment, pre- and postoperative visual acuity, hertel exophthalmometry measurements, diplopia, palpebral fissure height, unilateral versus bilateral decompression, decompression technique, fat volume removed, integrity of the periorbita, and follow-up duration. The presence or absence of diplopia was based on subjective reporting by the patient at the time of the final follow-up visit and was considered to be present if any form of diplopia was reported, including intermittent and gaze-evoked and diplopia in primary or downgaze. Orthoptic assessments were not performed as they were extremely difficult to obtain in the primary author’s city with limited capacity and lengthy waiting times. A total of 128 patient charts were reviewed. Of these, 123 charts had complete information regarding pre and postoperative diplopia and strabismus and were included in the analysis. Surgical Technique. All orbital decompressions were performed under general anesthesia. The lateral canthal area and inferior fornix were infiltrated with approximately 2.5 ml of 2% xylocaine with epinephrine 1:100,000 mixed 50/50 with bacteriostatic saline. The nasal mucosa was packed with neuro patties soaked in 4% cocaine. A lateral canthotomy and inferior cantholysis were performed followed by incision of the conjunctiva and lower eyelid retractors at the inferior border of the tarsal plate across its entire width. Blunt dissection was carried out in a preseptal plane down to the inferior orbital rim. The periorbita was incised at the rim and using blunt dissection was elevated from the floor of the orbit. The portion of the floor medial to the infraorbital canal was removed with preservation of the anterior 10 mm of the floor behind the rim. The inferomedial bony strut at the junction of the ethmoid and maxillary sinuses were also preserved (3–4 mm average width remaining). Periorbita in the area overlying the defect in the floor was usually left intact. The medial wall of the orbit was accessed via a transcaruncular incision. Periorbita was elevated from the medial wall. Anterior and posterior ethmoidal vessels were cauterized. Bone was removed to a level approximately 4 to 5 mm beyond the posterior ethmoidal vessel with preservation of 1 mm of bone below the level of the ethmoidal vessels and 10 mm of bone behind the orbital rim. If indicated, periorbita overlying the medial osteotomy and parallel to medial rectus (i.e., from approximately 4 to 5 mm beyond the posterior ethmoidal artery to 10 mm posterior to the orbital rim) was opened using a no. 12 blade to allow protrusion of the medial rectus and medial orbital tissue in the ethmoid sinus. Orbital fat removal was performed in the inferolateral aspect of the orbit by opening the periorbita between inferior rectus and lateral rectus and removing between 1 and 4 cm3 of intraconal fat. The transcaruncular incision and infratarsal incisions were closed with 7-0 chromic suture. The lateral canthal tendon was reapproximated with 4-0 vicryl suture. Postoperative Care. Patients were administered intraoperative doses of 8 to 16 mg of decadron intravenously. Postoperatively, they were given oral prednisone starting at 60 mg and tapering by 10 mg daily. Topical and systemic antibiotics were also prescribed. Follow-up visits were arranged at 1 week, 1, 3, and 6 months postoperatively. Statistical Analysis. A 2 × 2 analysis of variance (ANOVA) was performed with Surgical status (Pre vs. Post) and Eye (Right vs. Left) as within-subject variables on all observations. A 2 × 2 × 2 ANOVA was conducted on Hertel scores with Approach (intact vs. opened) as a between-subject factor, and Surgical Status (Pre vs. Post) and Eye (Right vs. Left) as within-subject variables. Chi-square with Yates correction was used to evaluate the significance of pre- and postoperative diplopia in patients who underwent 2-walled decompression with preservation versus opening of the periorbita.
138
RESULTS Women composed 74.0% of patients who underwent orbital decompression in this study. Mean age amongst women was 46.3 years (range 14–79 years) compared with men was 49.1 years (range of 17–82 years). Orbital decompression surgery was more commonly performed to improve cosmesis in women compared with men (76.9% vs 50.0%) (see Table 1). In contrast, decompression was performed more frequently in men compared with women (31.2% vs 11.0%) for optic neuropathy. This finding is consistent with previous reports that optic neuropathy more commonly affects men than women.13 Exposure keratitis was the indication for decompression in 18.8% of men versus 12.1% of women. Diplopia associated with restricted ocular motility was observed preoperatively in 26% of patients (n = 123 patients). The presence of postoperative diplopia was determined based on the patient’s reported symptoms at the time of their last clinical visit. Average follow-up duration was 19.2 months, while median follow-up duration was 10 months with a range of 1 to 90 months. Resolution of diplopia after surgery was observed in 9 of 32 patients (28.1%) patients. Postoperative prevalence of diplopia was 40.7%, with an incidence of new-onset diplopia in 29.7% of patients undergoing decompression surgery. These results are presented in Table 2. Almost all patients underwent decompression using a 2- or 3-wall decompression technique (Table 3). Given the limited number of 3-wall decompressions performed, further analysis was confined to the group of patients who underwent 2-wall decompression (n = 119). When patients are compared as to whether the periorbita was opened or left intact, the results of this study suggest that the former were more likely to have new-onset diplopia in the postoperative period. These results are summarized in Table 4. Pre- and postdecompression hertel measurements were recorded. Data from patients who underwent 2-wall decompression are summarized in Table 5. Data from the 1- and 3-wall decompressions are not presented because of the limited patient numbers in each group. Amongst all patients who underwent 2-wall decompression, there was a mean reduction
TABLE 1. Indication for decompression surgery Surgical indication Neuropathy Exposure keratitis Cosmesis
No. Overall cases percentage 20 17 86
16.3 13.8 69.9
Males (%)
Females (%)
31.2 (n = 10) 11.0 (n = 10) 18.8 (n = 6) 12.1 (n = 11) 50.0 (n = 16) 76.9 (n = 70)
n = 123.
TABLE 2. Diplopia prevalence and incidence Diplopia Preoperative Postoperative New-onset Resolved
No. cases
Percentage
32 50 27 9
26.0 (32/123) 40.7 (50/123) 29.7 (27/91) 28.1 (9/32)
n = 123.
TABLE 3. Effect of orbital decompression technique on diplopia Decompression No. Preoperative New-onset technique performed diplopia diplopia Resolution Single wall 2-walls 3-walls
1 119 3
0 30 2
0 26 1
0 9 0
n = 123.
© 2014 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.
Ophthal Plast Reconstr Surg, Vol. 30, No. 2, 2014
Effect of Orbital Decompression on Diplopia in Thyroid-Related Orbitopathy
TABLE 4. Effect of preservation versus incision of periobita on diplopia in 2-wall decompressions Decompression No. Preoperative New-onset technique performed diplopia diplopia Resolution Periorbita opened Periorbital intact
82
27
22
7
37
3
4
2
n = 119.
in hertel measurements of 3.07 mm. In those patients in whom the integrity of the periorbita was maintained, a mean reduction in hertel measurements of 2.90 mm was observed compared with those in whom the periorbita along the medial wall, floor, or both was opened, where a mean reduction of 3.12 mm was observed. Further analysis of those in whom the periorbita was opened revealed reductions of 2.94, 1.75, and 4.69 mm in hertel measurements postoperatively when periorbita along the medial wall only, floor only, or medial wall and floor was opened respectively. A 2 × 2 ANOVA was performed with surgical status (Pre vs. Post) and surgical site (Right vs. Left) as within-subject variables on all observations. Irrespective of technique, all patients improved about their Hertel scores, F (1, 104) = 263.05, mean squared error (MSe) = 3.75, p
