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Medial and Lateral Wall Decompression for Thyroid Ophthalmopathy
Medial and Lateral Wall Decompression for Thyroid Ophthalmopathy Charles R. Leone, Jr., M.D., Ken 1. Piest, M.D., and Richard J. Newman, M.D.
A two-wall decompression of the orbit, consisting of removal of the medial and lateral walls, was successful in eight patients with thyroid ophthalmopathy. The lateral wall was by removed by using the standard orbitotomy technique in addition to enlarging the space with a pneumatic burr, and the medial wall was removed through a direct medial canthal incision. Two patients had optic neuropathy, one had intermittent subluxation of the globe, and five had symptoms of exposure or increased pressure in the orbital area. In our eight patients, the two with optic neuropathy improved, the patient with subluxation of the globe became asymptomatic, and the other five had less exposure and were more comfortable. The amount of decompression ranged between 4 and 7 mm. The lacrimal sac was injured in one patient; temporary silicone intubation avoided any permanent sequela. continues to frustrate ophthalmologists and internists with its complex array of manifestations and unpredictable clinical course. Graves' disease can be treated medically, surgically, and with irradiation. When surgical decompression is indicated, a one- to four-wall decompression procedure using a variety of approaches may be used, each with its own advantages and associated complications.v' Frequently, the orbital floor is removed either alone or in conjunction with a medial wall decompression. This is an effective procedure, but complications involving extraocular GRAVES' DISEASE
Accepted for publication May 11, 1989. From the Department of Ophthalmology (Drs. Leone and Piest) and Department of Otolaryngology (Dr. Newman), University of Texas Health Science Center at San Antonio, Texas. Reprint requests to Charles R. Leone, [r., M.D., 7950 Floyd Curl Dr. #505, Medical Center Tower I, San Antonio, TX 78229.
160
muscle imbalance, infraorbital nerve anesthesia, hypo-ophthalmia, and recurrent sinusitis are common.v' We used a combined medial and lateral wall decompression procedure that was effective in reducing exophthalmos and relieving optic nerve compression while minimizing complications associated with the procedures involving the removal of the floor of the orbit.
Material and Methods The procedure was performed after administration of general anesthesia. The patient was placed in a reverse Trendelenburg position to reduce venous pressure to the head. The middle meatus was packed with three cottonoids soaked with cocaine 4%. The medial canthal and temporalis fossa areas were injected with 0.5% bupivacaine hydrochloride with 1:200,000 epinephrine hydrochloride. Intermarginal: sutures made of 6-0 silk over 5-mm #40 silicone band pegs were placed between the eyelids to protect the globe. The lateral wall decompression was performed first. An incision was made from the lateral canthus into the temporalis fossa for approximately 4 to 6 em (Fig. 1). Care must be taken not to extend the incision too far laterally to avoid injuring the frontal branch of the facial nerve. The lateral orbital rim was exposed and a vertical incision made in the periosteum, which was separated from the rim and the periorbita reflected from the lateral wall. With a malleable retractor inserted on the inner aspect of the wall to protect the orbital contents, a reciprocating saw was used to remove the lateral orbital rim. The bone cuts were at the level of the zygomatic arch and just above the zygomatic-frontal suture (Fig. 2). This allows removal of a 20- to 25-mm segment of bone. A rongeur was used to grasp the rim between the bone cuts and bend it backward, breaking it free from the posterior bone (Fig. 3). The rongeur is then used to remove the thin
©AMERICAN JOURNAL OF OPHTHALMOLOGY
108:160-166,
AUGUST,
1989
Vol. 108, No.2
Orbital Decompression for Thyroid Ophthalmopathy
Fig. 1 (Leone, Piest, and Newman). An incision is begun 5 mm from the lateral canthus into the temporalis fossa area for 4 to 6 em. An intermarginal suture of 6-0 silk is placed through #40 silicone band pegs to protect the globe.
161
Fig. 2 (Leone, Piest, and Newman). After the lateral rim has been exposed, a malleable retractor is inserted on the inner aspect of the lateral wall to protect the orbital contents. A reciprocating saw makes bone cuts at the level of the zygomatic arch and just above the zygomatic-frontal suture line.
)
Fig. 3 (Leone, Piest, and Newman). A rongeur is used to grasp the rim between the cuts and bend it backward, breaking it off at the thinner posterior wall.
Fig. 4 (Leone, Piest, and Newman). After the thinner bone of the lateral wall is removed with rongeurs, a 5-mm burr on an air drill is used to enlarge the entire opening, particularly in the area of the thicker sphenoid bone.
Fig. 5 (Leone, Piest, and Newman). The periorbita is incised, allowing the fat to prolapse.
Fig. 6 (Leone, Piest, and Newman). The fat is gently spread to break the fine septa, allowing it to prolapse more freely into the temporalis fossa.
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Fig. 7 (Leone, Piest, and Newman). A Penrose drain is inserted into the area of decompression to eliminate fluid accumulation. The subcutaneous layer is closed with 5-0 chromic catgut and the skin with the same or 5-0 polypropylene.
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August, 1989
Fig. 8 (Leone, Piest, and Newman). An incision is made in the medial canthus down to the periosteum approximately 1 cm from the canthal angle.
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Fig. 9 (Leone, Piest, and Newman). The medial canthal tendon together with the lacrimal sac are reflected laterally. The anterior ethmoidal artery is identified, coagulated, and severed.
Fig. 10 (Leone, Piest, and Newman). The ethmoid sinus is entered, with firm pressure applied to a periosteal elevator.
Fig. 11 (Leone, Piest, and Newman). Using the ethmoidal artery as a landmark, the bone is removed from just behind the posterior lacrimal crest to the area of the posterior ethmoidal artery. The mucosa and the air cells are obliterated followed by externalization of the ethmoid sinus into the middle meatus.
Fig. 12 (Leone, Piest, and Newman). The periorbita is incised with scissors beginning posterior to the lacrimal sac and taken as far back as the medial wall removal. Gentle spreading of the fat can be done to enhance prolapse of the orbital tissue into the sinus.
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Orbital Decompression for Thyroid Ophthalmopathy
Fig. 13 (Leone, Piest, and Newman). A coronal section through the retrobulbar space demonstrates the prolapse of the fat into the ethmoid sinus. bone of the lateral wall until the thicker sphenoid bone is reached. A pneumatic drill with a 5-mm burr was used to remove more of the bone to enlarge the bony window. The thicker sphenoid bone can be removed almost to the point of reaching the dura, further enlarging the decompressive space (Fig. 4). The periorbita was then incised (Fig. 5) and scissors were used to spread the fat gently to break the fine septa, allowing it to prolapse more easily into the temporalis fossa (Fig. 6). Only the subcutaneous tissues and skin were closed, and a Penrose drain was left in the temporalis fossa to eliminate any fluid accumulation (Fig. 7). The medial decompression was begun with a slightly curved incision in the medial canthal area adjacent to the medial canthal tendon and was extended far enough vertically to expose the entire medial wall (Fig. 8). After the periosteum was incised and the medial canthal tendon reflected, the lacrimal sac was retracted laterally and the medial wall exposed (Fig. 9). The anterior ethmoidal artery was identified and coagulated and used as a landmark for the superior extent of the medial wall removal, since the intracranial cavity lies above the ethmoidal arteries. The ethmoid sinus was entered with firm pressure applied with a periosteal elevator (Fig. 10). A Takahashi biting forceps or Kerosin punch was used to remove the bone piece by piece (Fig. 11). The air cells were obliterated and the mucosa removed as well. The ethmoid sinus was then externalized into the middle meatus with a hemostat, followed by the placement of a Telfa roll that extended to the external nares. The decompression was not taken beyond the posterior ethmoidal artery to
163
Fig. 14 (Leone, Piest, and Newman). The subcutaneous tissue and skin are closed with 5-0 chromic catgut suture. avoid injury to the optic nerve. The periorbita was incised with scissors beginning just posterior to the lacrimal sac and taken to the posterior extent of the decompression (Figs. 12 and 13). The lacrimal system was irrigated to make certain that the sac was not inadvertently ruptured; if injury had occurred, indwelling silicone tubes were inserted. The subcutaneous tissue and skin were closed with 5-0 chromic catgut suture (Fig. 14). During the procedure, the patient was given 4 mg of dexamethasone and a cephalosporin antibiotic intravenously; both drugs were continued postoperatively for 24 hours and then given orally for seven to ten days. The Telfa nasal pack was removed on postoperative day 1 and the Penrose drain was removed from the lateral incision after 48 hours.
Results Eight patients underwent medial and lateral orbital decompression. Four patients had bilateral procedures, giving a total of 12 eyes. The patients ranged in age from 47 to 68 years. There were five women and three men. Two patients had optic neuropathy. One was a 68year-old woman with a visual acuity of 20/400 in the right eye and a depressed visual-evoked potential. Her postoperative visual acuity was 20170+ and her visual-evoked potential was improved. The other was a 47-year-old man who had a preoperative visual acuity of 20/20 in the left eye, disk edema, and an enlarged blind spot. Postoperatively, his visual acuity improved to 20/20+, his disk edema resolved, and
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Fig. 15 (Leone, Piest, and Newman). Left, Preoperative axial computed tomography of patient who had intermittent subluxation of right globe between her eyelids. Right, Postoperative scan showing prolapse of the orbital tissues into the lateral and medial decompressive spaces.
his blind spot returned to almost normal size. A 49-year-old woman who had intermittent subluxation of the right globe between the eyelids underwent a successful 5-mm decompression. The remaining patients, who all had symptoms of exposure keratopathy, improved postoperatively. The amount of decompression ranged from 4 to 7 mm (average, 5.6 mm). There was no change in extraocular muscle movement in any patient.
Discussion Currently, the most common types of decompression techniques include removal of the orbital floor with or without the medial wall either by the transeyelid, inferior fornix, or transantral approaches, and the three-wall decompression which includes the lateral wall. The lateral wall decompression alone has not been believed to be effective unless combined with one of the other procedures, particularly in cases of compressive optic neuropathy.t" However, the computed tomographic scan in our patient who had intermittent subluxation of the right eye shows a significant prolapse of tissue into the temporalis fossa (Fig. 15). The four-wall decompression, which includes the orbital roof, can be used in extreme cases but requires the assistance of a neurosurgeon. In a four-wall decompression, a large portion of the sphenoid bone is removed in the apex of the orbit and the lateral one half of the orbital roof is removed, exposing the dura." Whenever the floor is included in the decompression procedure there is the potential for
extraocular muscle imbalance, hypo-ophthalmia, infraorbital nerve damage, and maxillary sinusitis.v" Losing the inferior support to the orbital tissues could cause a disturbance in motility, particularly if there was already compromise or restriction in muscle movement preoperatively. Diplopia in the primary position that had not been present preoperatively has been reported in up to 30% of cases in which some restriction was present before surgery. 7 Hypo-ophthalmia is the most difficult problem to manage and can be associated with motility problems because of the vertical misalignment or dropping of the globe. Moreover, it is a noticeable cosmetic deformity and can cause flattening of the supratarsal space of the upper eyelid. The muscle imbalance can be addressed with either prisms or muscle surgery. Hypoophthalmia requires a challenging orbital reconstructive procedure to raise the level of the globe with an implant to that of the opposite eye. Although every effort is made to preserve the neurovascular bundle, traction on the infraorbital nerve can cause partial or complete malfunction postoperatively. There is usually some infraorbital nerve anesthesia postoperatively, which disappears after several months. If function does not return, it can be disconcerting to the patient. Maxillary sinusitis is a common sequela since the sinus drains into the middle meatus, and pooling of old blood and secretions in the sinus floor can cause infection. This can be avoided by creating a nasal-antral window into the inferior meatus at the time of decompression to allow for gravitational drainage. Because of the potential problems, we strove to achieve a satisfactory decompression from
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Orbital Decompression for Thyroid Ophthalmopathy
both a functional and cosmetic standpoint while avoiding the floor of the orbit. In addition to removing the lateral rim and the thin portion of the lateral wall, using a high speed burr allows one to carry the decompression more posteriorly through the thick sphenoid bone. This not only relieves more pressure from the apex of the orbit but enlarges the decompression area. Although the temporalis muscle occupies the area into which the lateral decompression is occurring, it provides far less rigidity than the bony lateral orbital wall. After the periorbita is cut, gentle spreading of the fat with blunt scissors breaks the fine septa allowing the fat to prolapse more freely into the lateral space (Fig. 15). The lateral rim was not replaced in any of our patients and has not resulted in a cosmetic blemish.P-" In 45 lateral decompressions done by Long and Ellis,13 removing the lateral orbital rim was of no cosmetic significance. The potential complications in doing the lateral orbitotomy include damaging the frontal branch of the seventh cranial nerve if the incision is taken too far posteriorly, scarring, lymphedema from interruption of the lymphatic drainage, and a possibility of entering the cranial cavity. The direct medial canthal approach avoids the eyelids, and this eliminates the possibility of eyelid malposition.P:" With an ample incision and exerting careful traction against the lacrimal sac, adequate exposure of the wall can be obtained even to the area of the posterior ethmoidal air cells. This is particularly important in cases of optic neuropathy, since the greatest pressure from the enlarged extraocular muscles is near the apex of the orbit. We do not, however, routinely go beyond the posterior ethmoidal artery since it would bring us perilously close to the optic nerve. Moreover, it is important to keep the bony extirpation below the level of the ethmoidal vessels to preclude entering the anterior cranial fossa and producing a possible cerebral spinal fluid leak. Lacrimal injury is always a potential problem because of the prolonged traction over the sac in attempting to obtain maximum exposure in an orbit that is already compromised. Lacrimal irrigation should be carried out at the end of the procedure to ensure its patency and to uncover any possible rents. 16,1; In cases of lacrimal sac injury, silicone tubes should be inserted. Damage to the trochlea is a possibility as well, but if one avoids penetrating the periorbita in the anterior aspect of the superomedial quadrant, this complication should be rare.
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After approximately 4 to 7 mm of decompression, none of our patients lost vision or had worsening of extraocular muscle movement. This is the same amount of decompressive effect that has been reported with the antralethmoidal and three-wall approaches; yet, we have had none of the frequently encountered complications associated with those approaches as a result of removing the orbital floor. Two patients in our series had an improvement in their vision: visual acuity in a patient with optic neuropathy improved from 20/400 to 20170-, and a patient with optic disk edema had resolution of the edema over a three-month period. It is difficult to measure the exact amount of decompression since a Hertel exophthalmometer does not give a valid reading in eyes with the lateral rim removed. Nevertheless, assessment of the position of the globe in relationship to the nose and superior rim from side photographs has allowed us to make estimates as to the number of millimeters of decompression. The only significant complication in our eight patients was injury to a lacrimal sac, which required silicone intubation for several months. When the tube was removed, irrigation was easily accomplished and the system has remained patent. The goal of any decompression is to maximize the decompressive effect to save vision or protect the eye while minimizing side effects. Our technique of medial and lateral decompression eliminates removing the orbital floor, which is the cause of most complications. The eyelids and fornix are spared incisions, which eliminates eyelid malposition. This technique leaves the orbital floor intact, thus providing support for the orbital contents and lessening the chance for extraocular muscle imbalance, hypo-ophthalmia, sinusitis, and infraorbital nerve damage.
References 1. Leone, C. R., Jr.: The management of ophthalmic Graves' disease. Ophthalmology 91:770, 1984. 2. Small, R. G., and Meiring, N. L.: A combined orbital and antral approach to surgical decompression of the orbit. Ophthalmology 88:542, 1981. 3. Kennerdell, J. 5., and Marron, J. c.: An orbital decompression for severe dysthyroid ophthalmopathy. Ophthalmology 89:467, 1982. 4. Leone, C. R., and Bajandas, F. J.: Interior orbital decompression for dysthyroid optic neuropathy. Ophthalmology 88:525, 1981.
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5. McCord, C. D., [r.: Orbital decompression for Graves' disease. Exposure through lateral canthal and inferior fornix incision. Ophthalmology 88:533, 1981. 6. - - : Current trends in orbital decompression. Ophthalmology 92:21, 1985. 7. Shorr, N., Newhaus, R. W., and Baylis, H. 1.: Ocular motility problems after orbital decompression for dysthyroid ophthalmopathy. Ophthalmology 89:323, 1982. 8. McCord, C. D., Putnam, J. R., and Ugland, D. N.: Pressure-volume orbital measurement comparing decompression approaches. Ophthalmic Plast. Reconstr. Surg. 1:55, 1985. 9. Wolfe, S. A., and Hemmy, D.: How much does removing the lateral wall help in expanding the orbit? Ophthalmic Plast. Reconstr. Surg. 4:111, 1988. 10. Thalley, S. E., Oguna, J., and Jacobs, J. R.: Transantral approach for orbital decompression. In Smith, B. C. (ed.): Ophthalmic Plastic and Reconstructive Surgery. St. Louis, C. V. Mosby, 1987, pp. 1393-1400. 11. Wirtschafter, J. D., and Chu, A. E.: Lateral
August, 1989
orbitotomy without removal of the lateral orbital rim. Arch. Ophthalmol. 106:1463, 1988. 12. McCord, C. D., Jr.: A combined lateral and medial orbitotomy for exposure of optic nerve and orbital apex. Ophthalmic Surg. 9:58, 1978. 13. Long, J. C.; and Ellis, G. D.: Temporal decompression of the orbit for thyroid exophthalmos. Am. J. Ophthalmol. 62:1089, 1966. 14. Leone, C. R., [r.. Lloyd, W. C.; and Rylander, G.: Surgical repair of medial wall fractures. Am. J. Ophthalmol. 97:349, 1984. 15. Goldberg, R. A., Christenburgy, J. D., and Shorr, N.: Medial entropion following orbital decompression for dysthyroid ophthalmopathy. Ophthalmic Plast. Reconstr. Surg. 4:81, 1988. 16. Colvard, D. M., Waller, R. R., Neault, R. W., and DeSanto, L. W.: Nasolacrimal duct obstruction following transantral-ethmoidal orbital decompression. Ophthalmic Surg. 10:25, 1979. 17. Seiff, S. R., and Shorr, N.: Nasolacrimal drainage system obstruction after orbital decompression. Am. J. Ophthalmol. 106:204, 1988.
OPHTHALMIC MINIATURE
According to the theoretical view proposed by Thomas Young and more fully developed by Helmholtz, the eye perceives but three colors or wavelengths, and all the other colors and shades known to us arise from the compound of the primary ones in the eye. The light waves are received by a layer of the retina, called the rods and cones, where experiments have led investigators to believe that the sensation of sight is located. The layer is named for the shapes assumed by the optic nerve substance there, which is supposed to be tuned to the reception of color vibrations. Scientific American, April 1875
A two-wall decompression of the orbit, consisting of removal of the medial and lateral walls, was successful in eight patients with thyroid ophthalmopathy. The lateral wall was by removed by using the standard orbitotomy technique in addition to enlarging the space with a pneumatic burr, and the medial wall was removed through a direct medial canthal incision. Two patients had optic neuropathy, one had intermittent subluxation of the globe, and five had symptoms of exposure or increased pressure in the orbital area. In our eight patients, the two with optic neuropathy improved, the patient with subluxation of the globe became asymptomatic, and the other five had less exposure and were more comfortable. The amount of decompression ranged between 4 and 7 mm. The lacrimal sac was injured in one patient; temporary silicone intubation avoided any permanent sequela. continues to frustrate ophthalmologists and internists with its complex array of manifestations and unpredictable clinical course. Graves' disease can be treated medically, surgically, and with irradiation. When surgical decompression is indicated, a one- to four-wall decompression procedure using a variety of approaches may be used, each with its own advantages and associated complications.v' Frequently, the orbital floor is removed either alone or in conjunction with a medial wall decompression. This is an effective procedure, but complications involving extraocular GRAVES' DISEASE
Accepted for publication May 11, 1989. From the Department of Ophthalmology (Drs. Leone and Piest) and Department of Otolaryngology (Dr. Newman), University of Texas Health Science Center at San Antonio, Texas. Reprint requests to Charles R. Leone, [r., M.D., 7950 Floyd Curl Dr. #505, Medical Center Tower I, San Antonio, TX 78229.
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muscle imbalance, infraorbital nerve anesthesia, hypo-ophthalmia, and recurrent sinusitis are common.v' We used a combined medial and lateral wall decompression procedure that was effective in reducing exophthalmos and relieving optic nerve compression while minimizing complications associated with the procedures involving the removal of the floor of the orbit.
Material and Methods The procedure was performed after administration of general anesthesia. The patient was placed in a reverse Trendelenburg position to reduce venous pressure to the head. The middle meatus was packed with three cottonoids soaked with cocaine 4%. The medial canthal and temporalis fossa areas were injected with 0.5% bupivacaine hydrochloride with 1:200,000 epinephrine hydrochloride. Intermarginal: sutures made of 6-0 silk over 5-mm #40 silicone band pegs were placed between the eyelids to protect the globe. The lateral wall decompression was performed first. An incision was made from the lateral canthus into the temporalis fossa for approximately 4 to 6 em (Fig. 1). Care must be taken not to extend the incision too far laterally to avoid injuring the frontal branch of the facial nerve. The lateral orbital rim was exposed and a vertical incision made in the periosteum, which was separated from the rim and the periorbita reflected from the lateral wall. With a malleable retractor inserted on the inner aspect of the wall to protect the orbital contents, a reciprocating saw was used to remove the lateral orbital rim. The bone cuts were at the level of the zygomatic arch and just above the zygomatic-frontal suture (Fig. 2). This allows removal of a 20- to 25-mm segment of bone. A rongeur was used to grasp the rim between the bone cuts and bend it backward, breaking it free from the posterior bone (Fig. 3). The rongeur is then used to remove the thin
©AMERICAN JOURNAL OF OPHTHALMOLOGY
108:160-166,
AUGUST,
1989
Vol. 108, No.2
Orbital Decompression for Thyroid Ophthalmopathy
Fig. 1 (Leone, Piest, and Newman). An incision is begun 5 mm from the lateral canthus into the temporalis fossa area for 4 to 6 em. An intermarginal suture of 6-0 silk is placed through #40 silicone band pegs to protect the globe.
161
Fig. 2 (Leone, Piest, and Newman). After the lateral rim has been exposed, a malleable retractor is inserted on the inner aspect of the lateral wall to protect the orbital contents. A reciprocating saw makes bone cuts at the level of the zygomatic arch and just above the zygomatic-frontal suture line.
)
Fig. 3 (Leone, Piest, and Newman). A rongeur is used to grasp the rim between the cuts and bend it backward, breaking it off at the thinner posterior wall.
Fig. 4 (Leone, Piest, and Newman). After the thinner bone of the lateral wall is removed with rongeurs, a 5-mm burr on an air drill is used to enlarge the entire opening, particularly in the area of the thicker sphenoid bone.
Fig. 5 (Leone, Piest, and Newman). The periorbita is incised, allowing the fat to prolapse.
Fig. 6 (Leone, Piest, and Newman). The fat is gently spread to break the fine septa, allowing it to prolapse more freely into the temporalis fossa.
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Fig. 7 (Leone, Piest, and Newman). A Penrose drain is inserted into the area of decompression to eliminate fluid accumulation. The subcutaneous layer is closed with 5-0 chromic catgut and the skin with the same or 5-0 polypropylene.
~
,i
'
August, 1989
Fig. 8 (Leone, Piest, and Newman). An incision is made in the medial canthus down to the periosteum approximately 1 cm from the canthal angle.
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iJ/1 '. IIVt'
Fig. 9 (Leone, Piest, and Newman). The medial canthal tendon together with the lacrimal sac are reflected laterally. The anterior ethmoidal artery is identified, coagulated, and severed.
Fig. 10 (Leone, Piest, and Newman). The ethmoid sinus is entered, with firm pressure applied to a periosteal elevator.
Fig. 11 (Leone, Piest, and Newman). Using the ethmoidal artery as a landmark, the bone is removed from just behind the posterior lacrimal crest to the area of the posterior ethmoidal artery. The mucosa and the air cells are obliterated followed by externalization of the ethmoid sinus into the middle meatus.
Fig. 12 (Leone, Piest, and Newman). The periorbita is incised with scissors beginning posterior to the lacrimal sac and taken as far back as the medial wall removal. Gentle spreading of the fat can be done to enhance prolapse of the orbital tissue into the sinus.
Vol. 108, No.2
Orbital Decompression for Thyroid Ophthalmopathy
Fig. 13 (Leone, Piest, and Newman). A coronal section through the retrobulbar space demonstrates the prolapse of the fat into the ethmoid sinus. bone of the lateral wall until the thicker sphenoid bone is reached. A pneumatic drill with a 5-mm burr was used to remove more of the bone to enlarge the bony window. The thicker sphenoid bone can be removed almost to the point of reaching the dura, further enlarging the decompressive space (Fig. 4). The periorbita was then incised (Fig. 5) and scissors were used to spread the fat gently to break the fine septa, allowing it to prolapse more easily into the temporalis fossa (Fig. 6). Only the subcutaneous tissues and skin were closed, and a Penrose drain was left in the temporalis fossa to eliminate any fluid accumulation (Fig. 7). The medial decompression was begun with a slightly curved incision in the medial canthal area adjacent to the medial canthal tendon and was extended far enough vertically to expose the entire medial wall (Fig. 8). After the periosteum was incised and the medial canthal tendon reflected, the lacrimal sac was retracted laterally and the medial wall exposed (Fig. 9). The anterior ethmoidal artery was identified and coagulated and used as a landmark for the superior extent of the medial wall removal, since the intracranial cavity lies above the ethmoidal arteries. The ethmoid sinus was entered with firm pressure applied with a periosteal elevator (Fig. 10). A Takahashi biting forceps or Kerosin punch was used to remove the bone piece by piece (Fig. 11). The air cells were obliterated and the mucosa removed as well. The ethmoid sinus was then externalized into the middle meatus with a hemostat, followed by the placement of a Telfa roll that extended to the external nares. The decompression was not taken beyond the posterior ethmoidal artery to
163
Fig. 14 (Leone, Piest, and Newman). The subcutaneous tissue and skin are closed with 5-0 chromic catgut suture. avoid injury to the optic nerve. The periorbita was incised with scissors beginning just posterior to the lacrimal sac and taken to the posterior extent of the decompression (Figs. 12 and 13). The lacrimal system was irrigated to make certain that the sac was not inadvertently ruptured; if injury had occurred, indwelling silicone tubes were inserted. The subcutaneous tissue and skin were closed with 5-0 chromic catgut suture (Fig. 14). During the procedure, the patient was given 4 mg of dexamethasone and a cephalosporin antibiotic intravenously; both drugs were continued postoperatively for 24 hours and then given orally for seven to ten days. The Telfa nasal pack was removed on postoperative day 1 and the Penrose drain was removed from the lateral incision after 48 hours.
Results Eight patients underwent medial and lateral orbital decompression. Four patients had bilateral procedures, giving a total of 12 eyes. The patients ranged in age from 47 to 68 years. There were five women and three men. Two patients had optic neuropathy. One was a 68year-old woman with a visual acuity of 20/400 in the right eye and a depressed visual-evoked potential. Her postoperative visual acuity was 20170+ and her visual-evoked potential was improved. The other was a 47-year-old man who had a preoperative visual acuity of 20/20 in the left eye, disk edema, and an enlarged blind spot. Postoperatively, his visual acuity improved to 20/20+, his disk edema resolved, and
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Fig. 15 (Leone, Piest, and Newman). Left, Preoperative axial computed tomography of patient who had intermittent subluxation of right globe between her eyelids. Right, Postoperative scan showing prolapse of the orbital tissues into the lateral and medial decompressive spaces.
his blind spot returned to almost normal size. A 49-year-old woman who had intermittent subluxation of the right globe between the eyelids underwent a successful 5-mm decompression. The remaining patients, who all had symptoms of exposure keratopathy, improved postoperatively. The amount of decompression ranged from 4 to 7 mm (average, 5.6 mm). There was no change in extraocular muscle movement in any patient.
Discussion Currently, the most common types of decompression techniques include removal of the orbital floor with or without the medial wall either by the transeyelid, inferior fornix, or transantral approaches, and the three-wall decompression which includes the lateral wall. The lateral wall decompression alone has not been believed to be effective unless combined with one of the other procedures, particularly in cases of compressive optic neuropathy.t" However, the computed tomographic scan in our patient who had intermittent subluxation of the right eye shows a significant prolapse of tissue into the temporalis fossa (Fig. 15). The four-wall decompression, which includes the orbital roof, can be used in extreme cases but requires the assistance of a neurosurgeon. In a four-wall decompression, a large portion of the sphenoid bone is removed in the apex of the orbit and the lateral one half of the orbital roof is removed, exposing the dura." Whenever the floor is included in the decompression procedure there is the potential for
extraocular muscle imbalance, hypo-ophthalmia, infraorbital nerve damage, and maxillary sinusitis.v" Losing the inferior support to the orbital tissues could cause a disturbance in motility, particularly if there was already compromise or restriction in muscle movement preoperatively. Diplopia in the primary position that had not been present preoperatively has been reported in up to 30% of cases in which some restriction was present before surgery. 7 Hypo-ophthalmia is the most difficult problem to manage and can be associated with motility problems because of the vertical misalignment or dropping of the globe. Moreover, it is a noticeable cosmetic deformity and can cause flattening of the supratarsal space of the upper eyelid. The muscle imbalance can be addressed with either prisms or muscle surgery. Hypoophthalmia requires a challenging orbital reconstructive procedure to raise the level of the globe with an implant to that of the opposite eye. Although every effort is made to preserve the neurovascular bundle, traction on the infraorbital nerve can cause partial or complete malfunction postoperatively. There is usually some infraorbital nerve anesthesia postoperatively, which disappears after several months. If function does not return, it can be disconcerting to the patient. Maxillary sinusitis is a common sequela since the sinus drains into the middle meatus, and pooling of old blood and secretions in the sinus floor can cause infection. This can be avoided by creating a nasal-antral window into the inferior meatus at the time of decompression to allow for gravitational drainage. Because of the potential problems, we strove to achieve a satisfactory decompression from
Vol. 108, No.2
Orbital Decompression for Thyroid Ophthalmopathy
both a functional and cosmetic standpoint while avoiding the floor of the orbit. In addition to removing the lateral rim and the thin portion of the lateral wall, using a high speed burr allows one to carry the decompression more posteriorly through the thick sphenoid bone. This not only relieves more pressure from the apex of the orbit but enlarges the decompression area. Although the temporalis muscle occupies the area into which the lateral decompression is occurring, it provides far less rigidity than the bony lateral orbital wall. After the periorbita is cut, gentle spreading of the fat with blunt scissors breaks the fine septa allowing the fat to prolapse more freely into the lateral space (Fig. 15). The lateral rim was not replaced in any of our patients and has not resulted in a cosmetic blemish.P-" In 45 lateral decompressions done by Long and Ellis,13 removing the lateral orbital rim was of no cosmetic significance. The potential complications in doing the lateral orbitotomy include damaging the frontal branch of the seventh cranial nerve if the incision is taken too far posteriorly, scarring, lymphedema from interruption of the lymphatic drainage, and a possibility of entering the cranial cavity. The direct medial canthal approach avoids the eyelids, and this eliminates the possibility of eyelid malposition.P:" With an ample incision and exerting careful traction against the lacrimal sac, adequate exposure of the wall can be obtained even to the area of the posterior ethmoidal air cells. This is particularly important in cases of optic neuropathy, since the greatest pressure from the enlarged extraocular muscles is near the apex of the orbit. We do not, however, routinely go beyond the posterior ethmoidal artery since it would bring us perilously close to the optic nerve. Moreover, it is important to keep the bony extirpation below the level of the ethmoidal vessels to preclude entering the anterior cranial fossa and producing a possible cerebral spinal fluid leak. Lacrimal injury is always a potential problem because of the prolonged traction over the sac in attempting to obtain maximum exposure in an orbit that is already compromised. Lacrimal irrigation should be carried out at the end of the procedure to ensure its patency and to uncover any possible rents. 16,1; In cases of lacrimal sac injury, silicone tubes should be inserted. Damage to the trochlea is a possibility as well, but if one avoids penetrating the periorbita in the anterior aspect of the superomedial quadrant, this complication should be rare.
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After approximately 4 to 7 mm of decompression, none of our patients lost vision or had worsening of extraocular muscle movement. This is the same amount of decompressive effect that has been reported with the antralethmoidal and three-wall approaches; yet, we have had none of the frequently encountered complications associated with those approaches as a result of removing the orbital floor. Two patients in our series had an improvement in their vision: visual acuity in a patient with optic neuropathy improved from 20/400 to 20170-, and a patient with optic disk edema had resolution of the edema over a three-month period. It is difficult to measure the exact amount of decompression since a Hertel exophthalmometer does not give a valid reading in eyes with the lateral rim removed. Nevertheless, assessment of the position of the globe in relationship to the nose and superior rim from side photographs has allowed us to make estimates as to the number of millimeters of decompression. The only significant complication in our eight patients was injury to a lacrimal sac, which required silicone intubation for several months. When the tube was removed, irrigation was easily accomplished and the system has remained patent. The goal of any decompression is to maximize the decompressive effect to save vision or protect the eye while minimizing side effects. Our technique of medial and lateral decompression eliminates removing the orbital floor, which is the cause of most complications. The eyelids and fornix are spared incisions, which eliminates eyelid malposition. This technique leaves the orbital floor intact, thus providing support for the orbital contents and lessening the chance for extraocular muscle imbalance, hypo-ophthalmia, sinusitis, and infraorbital nerve damage.
References 1. Leone, C. R., Jr.: The management of ophthalmic Graves' disease. Ophthalmology 91:770, 1984. 2. Small, R. G., and Meiring, N. L.: A combined orbital and antral approach to surgical decompression of the orbit. Ophthalmology 88:542, 1981. 3. Kennerdell, J. 5., and Marron, J. c.: An orbital decompression for severe dysthyroid ophthalmopathy. Ophthalmology 89:467, 1982. 4. Leone, C. R., and Bajandas, F. J.: Interior orbital decompression for dysthyroid optic neuropathy. Ophthalmology 88:525, 1981.
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5. McCord, C. D., [r.: Orbital decompression for Graves' disease. Exposure through lateral canthal and inferior fornix incision. Ophthalmology 88:533, 1981. 6. - - : Current trends in orbital decompression. Ophthalmology 92:21, 1985. 7. Shorr, N., Newhaus, R. W., and Baylis, H. 1.: Ocular motility problems after orbital decompression for dysthyroid ophthalmopathy. Ophthalmology 89:323, 1982. 8. McCord, C. D., Putnam, J. R., and Ugland, D. N.: Pressure-volume orbital measurement comparing decompression approaches. Ophthalmic Plast. Reconstr. Surg. 1:55, 1985. 9. Wolfe, S. A., and Hemmy, D.: How much does removing the lateral wall help in expanding the orbit? Ophthalmic Plast. Reconstr. Surg. 4:111, 1988. 10. Thalley, S. E., Oguna, J., and Jacobs, J. R.: Transantral approach for orbital decompression. In Smith, B. C. (ed.): Ophthalmic Plastic and Reconstructive Surgery. St. Louis, C. V. Mosby, 1987, pp. 1393-1400. 11. Wirtschafter, J. D., and Chu, A. E.: Lateral
August, 1989
orbitotomy without removal of the lateral orbital rim. Arch. Ophthalmol. 106:1463, 1988. 12. McCord, C. D., Jr.: A combined lateral and medial orbitotomy for exposure of optic nerve and orbital apex. Ophthalmic Surg. 9:58, 1978. 13. Long, J. C.; and Ellis, G. D.: Temporal decompression of the orbit for thyroid exophthalmos. Am. J. Ophthalmol. 62:1089, 1966. 14. Leone, C. R., [r.. Lloyd, W. C.; and Rylander, G.: Surgical repair of medial wall fractures. Am. J. Ophthalmol. 97:349, 1984. 15. Goldberg, R. A., Christenburgy, J. D., and Shorr, N.: Medial entropion following orbital decompression for dysthyroid ophthalmopathy. Ophthalmic Plast. Reconstr. Surg. 4:81, 1988. 16. Colvard, D. M., Waller, R. R., Neault, R. W., and DeSanto, L. W.: Nasolacrimal duct obstruction following transantral-ethmoidal orbital decompression. Ophthalmic Surg. 10:25, 1979. 17. Seiff, S. R., and Shorr, N.: Nasolacrimal drainage system obstruction after orbital decompression. Am. J. Ophthalmol. 106:204, 1988.
OPHTHALMIC MINIATURE
According to the theoretical view proposed by Thomas Young and more fully developed by Helmholtz, the eye perceives but three colors or wavelengths, and all the other colors and shades known to us arise from the compound of the primary ones in the eye. The light waves are received by a layer of the retina, called the rods and cones, where experiments have led investigators to believe that the sensation of sight is located. The layer is named for the shapes assumed by the optic nerve substance there, which is supposed to be tuned to the reception of color vibrations. Scientific American, April 1875