Aims To report the outcome of orbital implant removal and dermis fat graft (DFG) implantation in patients with chronic anophthalmic socket pain (ASP), in whom all detectable causes of pain had been ruled out and medical management had failed.
Methods Retrospective, multicentre case series. A review of all cases undergoing orbital implant replacement with DFG between 2007 and 2013 was conducted at the University of Iowa Hospitals and Clinics (UIHC), USA, and St. Erik Eye Hospital, Sweden. Inclusion criteria included (1) chronic ASP >2 years and unresponsive to treatment, (2) absence of pathological or structural cause for pain established by socket examination and orbital imaging, and (3) minimum 12-month post-surgical follow-up.
Results Six cases with chronic ASP were identified, four were post-enucleation and two were eviscerated at an average age of 45 years. The incidence of chronic ASP among enucleations at UIHC over a 6-year period was 0.7%. Indications for enucleation and evisceration included tumours and glaucoma. Intractable ASP had been present for an average of 11 years and persisted despite medical management. All patients were free of pain within 3 months of implant removal and DFG placement and remained pain free at an average 24 months following surgery.
Conclusions Orbital implant replacement with DFG was effective at relieving chronic ASP, and pain resolution was sustained in all cases. This surgical intervention may be a useful management option for patients in whom all detectable causes of chronic pain have been excluded and have failed medical pain management.
- Treatment Surgery
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Although enucleation and evisceration are generally effective in relieving pre-existing ocular pain,1 ,2 some patients develop anophthalmic socket pain (ASP) postoperatively even when the ocular pain was not present before removal of the eye. The pain and discomfort may range from trivial to a degree that affects daily life.3 Persistent or chronic ASP is uncommon.4–8
There are a number of conditions, some more common than others (box 1), that can cause ASP including eyelid malpositions, conjunctival problems, prosthesis issues, implant problems, socket problems, referred pain from adjacent areas, and a number of ‘other’ rarer entities.3–41
Causes of chronic anophthalmic socket pain
Pyogenic granulomas, conjunctival inclusion cysts, giant papillary conjunctivitis, neoplasia (squamous cell), discharge and irritation
Fitting problems, prosthetic surface breakdown, scratches, deposits, allergic reaction to the ocular prosthesis
Infection, inflammation, migration, exposure, host-reaction to implant
Recurrent or new malignancy, amputation neuroma, trochleitis, scleritis (post-evisceration)
Entropion, ectropion, incomplete eyelid closure
Skull base/sinus tumours, post-herpetic neuralgia
Phantom eye pain, complex regional pain syndrome, drug dependency, psychological or psychiatric disease, factitious
In the majority of cases, the cause of pain can be identified from a detailed medical history and careful physical examination supported if necessary by orbital imaging. Chronic or persistent pain of months to years in duration in whom a pathological or structural cause cannot be readily identified is rare. These patients often prove a management challenge. Herein we present six such cases managed by removal of the orbital implant and replacement with a dermis fat graft (DFG).
A retrospective, multicentre study of chronic ASP was conducted at the University of Iowa Hospitals and Clinics (UIHC), Iowa City, and St. Erik Eye Hospital (SEEH), Stockholm. Cases were identified from a database of consecutive patients undergoing implant removal and DFG implantation for the treatment of chronic ASP between 2007 and 2013. At UIHC, all consecutive cases undergoing enucleation and evisceration between 2007 and 2013 were also identified. Inclusion criteria included (1) patients with chronic ASP following enucleation or evisceration—chronic pain was defined as being present for >2 years and unresponsive to conservative treatment; (2) a detailed socket examination and orbital imaging had ruled out pathological and structural disease including prosthesis-related problems, lacrimal insufficiency, infection, implant exposure, trochleitis and neoplasm; (3) the patient had undergone removal of the orbital implant and placement of a DFG; and (4) minimum of 12 months' follow-up. Data were collected on patient age at enucleation/evisceration, indication for primary surgery, time to onset of pain, features of socket pain and other associated symptoms, medical and surgical treatments of chronic ASP, outcome following implant removal and DFG and length of postsurgical follow-up.
Six cases with chronic ASP were identified who had undergone orbital implant removal and DFG at the two centres (three at UIHC and three at SEEH) over a 6-year period. A summary of the clinical details and outcomes of all six patients is shown in table 1. Four cases underwent enucleation, and two were eviscerated at an average age of 45 years (range 3–79), four were men. The incidence of chronic ASP among cases of enucleation/evisceration at one centre (UIHC) over a 6-year period was 0.7% (2/291—the third case from this centre had undergone enucleation outside of this review period).
Indications for enucleation/evisceration included malignant melanoma (n=1), optic nerve glioma (n=1), blind painful eyes due to congenital glaucoma (n=1), rubeotic glaucoma (n=2) and retinal detachment (n=1). Chronic ASP had been present for an average of 11 years (range 3–34) and persisted despite medical treatment including analgesics, antibiotics and anti-inflammatories. All patients underwent orbital imaging for evaluation of structural pathology including malignancy. All patients were free of pain within 3 months of implant removal and DFG implantation and remained pain free at an average 24 months (range 16–38) following surgery. None required further medical or surgical intervention.
A 38-year-old woman underwent bilateral enucleation for blind painful eyes secondary to congenital glaucoma with insertion of Universal orbital implants (Oculo-Plastik, Montreal). Over the next 20 years she developed progressive ASP on the left side only, a constant orbital ache with sporadic stabbing pains, radiating to the vertex of the head and associated with hyperaesthesia around the left eye socket and worse in cold weather. She was seen by a neurologist and had gained mild relief from oxycodone but not gabapentin. Orbital injections of dexamethasone and lidocaine were short lived, and a retrobulbar injection of alcohol was ineffective. An orbital CT scan revealed calcification surrounding and posterior to the orbital implants (figure 1A–C), which was significantly greater on the left compared with the asymptomatic right side. At age 71, 34 years following enucleation, her left orbital implant was replaced with a DFG. Histopathology of the tissues around the implant showed focal areas of calcification and chronic granulomatous inflammation notably surrounding the peripheral nerves (figure 1D, E). Stains for organisms were negative. She remains pain free 19 months following implant removal.
A 67-year-old man underwent left enucleation and insertion of a porous polyethylene orbital implant (Porex Surgical, College Park, Georgia, USA) for a blind painful eye secondary to ischaemic central retinal vein occlusion. Three years following enucleation he developed frequent sharp pains of the left eye socket radiating to the left temple and associated with headaches. He has been evaluated by a neurologist, and investigations for giant cell arteritis were negative. He received oral antibiotics, anti-inflammatories and analgesics. A CT scan showed soft tissue thickening and fat stranding within the left orbit suggestive of low-grade infection or inflammation. Six years following enucleation he underwent removal of the orbital implant, with placement of a DFG. He remains pain free 16 months following surgery.
A 57-year-old man underwent left enucleation and insertion of a porous polyethylene orbital implant for asymptomatic ciliary body malignant melanoma. Immediately following enucleation he reported a constant pressure sensation in the left eye socket radiating to the left side of the head associated with hourly episodes of sharp shooting pains, worsened by stress. He was assessed by a neurologist and the pain clinic and was taking tramadol daily. There was no benefit from prednisone, gabapentin or oxcarbazepine. Several positron emission tomography scans performed as part of his metastatic workup showed persistent abnormal uptake in the left eye socket. MRI 12 months following enucleation showed only postoperative changes and no evidence of recurrent melanoma. Eighteen months following enucleation, a small implant exposure was successfully treated with a scleral patch graft followed by oral antibiotics. Due to persistent ASP, 3 years following enucleation, he underwent removal of orbital implant and placement of a DFG. Within weeks his symptoms subsided, and he remains pain free 26 months following surgery.
A 77-year-old woman underwent left enucleation without an orbital implant for a blind painful eye secondary to ischaemic central retinal vein occlusion. Two years later she underwent secondary implantation of a 18 mm aluminium oxide orbital implant (Alumina, FCI, Issy-Les-Moulineaux, France). Immediately following surgery she developed a constant aching pain in and around the left socket radiating to the left side of the head. A CT scan was non-contributory. Four years later, due to chronic ASP, she underwent removal of orbital implant and placement of a DFG; she remains pain free 28 months following surgery.
A 3-year-old female underwent right evisceration with a 17 mm silicone orbital implant for a blind painful eye secondary to optic nerve glioma. Immediately following surgery she developed deep dull aching orbital pain, worsened by palpation of the implant. At age 8, neurosurgery debulked the glioma and the orbital implant was exchanged with a smaller 16 mm silicone implant. She continued to have persistent ASP, which was controlled medically for 8 years after but then relapsed. A CT scan was non-contributory. Thirteen years following evisceration, she underwent removal of the orbital implant and its scleral shell and placement of a DFG. She has remained pain free 26 months later.
A 26-year-old man underwent left evisceration with a 22 mm silicone orbital implant for a blind painful eye secondary to retinal detachment. One month following surgery he developed dull, aching orbital pain. There was no evidence of implant exposure; nevertheless, he received a course of oral antibiotics, which did not alleviate his pain. One year later, due to persistent ASP, a CT scan was performed that was non-contributory. Increasing ASP 2 years later prompted a repeat CT scan now showing fluid around the implant. The implant and sclera were removed. Cultures of the fluid found surrounding the implant were negative, and his pain persisted. Two years later, 5 years following primary evisceration, he underwent implantation of DFG to the left eye socket. Following surgery, his pain resolved and he remains pain free 38 months later.
Chronic ASP is reported to occur in 0.3–2.2% of post-enucleation/post-evisceration cases.4–8 It is an uncommon complication of enucleation and evisceration surgery that can be challenging to manage and may commit the patient to chronic pain medication with their associated problems of dependency as illustrated in several of the cases reported herein. Of the six cases we present with persistent socket pain, there were two patients (cases 1 and 3) with suspected causes while four cases had no identifiable cause. Case 1 had bilateral simultaneous enucleation and insertion of identical orbital implants but developed chronic ASP years later on the left side only. Histopathology of the explanted implant was suggestive of a foreign body reaction that may have been the cause for her chronic pain. Case 3 developed exposure of the implant 18 months after enucleation but had persistent pain despite successful treatment with a scleral patch graft. Chronic infection of the implant may have been the cause of the ASP, which resolved with implant removal. In the other four patients with chronic socket pain, there was no identifiable cause.
Following a detailed history and careful physical exam, there are a number of more rare and unusual entities that should be considered. Infection of an orbital implant should be suspected if there is therapy-resistant inflammation or discharge, pain or recurrent pyogenic granuloma. Jordan et al9 examined 15 explanted hydroxyapatite implants and found clinical evidence of infection in 13 cases. The symptoms and signs in the majority of patients were not immediately indicative of implant infection, but infection was suspected due to the persistence of symptoms. In all but one patient, the symptoms resolved promptly with implant removal. Shields et al5 reported a case (1/250) of persistent ASP in a child with mucoid socket discharge and an upper respiratory illness, 3 months after enucleation. Although conjunctival and blood cultures were negative, the persistent pain was presumed to be secondary to orbital infection and resolved with intravenous antibiotics.
Other reports of chronic ASP with a possible infective aetiology include a case by Christmas et al4 (1/342) with 3 years of ASP following enucleation, which was cured by replacement of an Iowa implant with an acrylic sphere. Custer and McCaffery7 reported one case (1/112) of persistent ASP following enucleation with a hydroxyapatite implant in a severely phthisical eye. The pain was attributed to anterior attachment of the contracted rectus muscles and was relieved after release of the muscles and implant replacement with a sclera-covered acrylic sphere.
Phantom eye syndrome needs consideration in persistent ASP where no cause can be readily identified; this may have been the cause in at least some of our cases. It is defined as any sensation originating in the eye despite its absence with no significant clinical cause for the pain. Phantom pain is a sequel of limb amputations in up to 80% of amputees,43 with 70% affected even several decades after amputation. The incidence of phantom eye pain ranges from 23% to 28%.30 ,44 ,45 The difference in incidence between phantom eye pain (23–28%) and ASP (0.2–3%) is significant and may be due to the fact that the former was derived from structured interviews and questionnaires focusing on pain in anophthalmic patients, who were not necessarily attending the hospital, but the studies on ASP certainly represent patients whose pain was severe enough to actively seek medical intervention. Phantom eye syndrome includes visual hallucinations, pain and tactile sensations. The pathophysiological mechanisms may be categorised into supraspinal, spinal and peripheral mechanisms.46 Supraspinal mechanisms refer to reorganisation of the somatosensory cortex representing the deafferentated body part. Changes in the spinal cord regulatory mechanisms for sensory input from the missing body part result in increased autonomous activity of the dorsal horn neurons.46 Peripherally, a severed nerve initiates inflammation and regenerative sprouting of axons, resulting in an amputation neuroma, which may contribute to phantom pain.
Rasmussen et al30 found 39/173 patients (23%) with phantom pain following enucleation, evisceration and exenteration; 38% had no presurgical ocular pain. The pain was described as penetrating, gnawing, shooting or a mixture of different pain qualities, experienced daily in a third of patients. Cold weather, psychological stress and fatigue were triggers for phantom pain, and risk factors were painful blind eyes prior to surgery and the presence of an orbital implant. Similarities with phantom limb pain suggest medications such as neuroleptics and tricyclic antidepressants may be of help.
Microscopic amputation neuromas, another cause of chronic ASP, refer to a benign proliferation of neural tissue after severing a peripheral nerve and are diagnosed by histological examination.23 ,24 Microscopic amputation neuromas may reasonably have been the cause of ASP in at least some of our cases; unfortunately, however, in only one of the six cases was orbital tissue sent for histopathological examination. One mechanism to explain the chronic pain of amputation neuromas is infiltration of scar tissue by the severed small sensory nerves, excited by mechanical distortion,47 and potentially influenced by activity of the autonomic system. Symptomatic neuromas are thought to be the result of tractional or compression forces on the nerve. In an anophthalmic orbit, the ciliary nerves may be prone to development of neuromas; however, the rarity of chronic ASP would suggest most neuromas are asymptomatic. This maybe due to the fact that within the orbit these nerves are usually not exposed to any mechanical trauma.48 Using MRI-dynamic colour mapping, Abramoff et al49 showed that tissue motion is decreased in the enucleated orbit, in comparison with the normal orbit, and that the optic nerve is usually attached to the implant, a feature seen on orbital imaging in all our cases as shown in figure 1C. They postulate that increased stiffness of orbital soft tissue and optic nerve attachment after enucleation may play a role in susceptible patients in the development of symptomatic microscopic amputation neuroma.
Messmer et al23 described two cases who presented with a socket mass and chronic ASP 17–25 years following surgery. CT scan revealed a cystic structure and adjacent soft tissue masses that in both cases were removed en block and reconstructed using DFG. Histopathology showed conjunctival inclusion cysts and irregular tangles of proliferating axons, Schwann cells and connective tissue. Neither patient experienced further pain following surgery. Glatt et al24 described a case who developed severe persistent ASP 47 years after enucleation for a congenitally abnormal eye. The ASP fully resolved after the metallic implant and its pseudocapsule were replaced by a hydroxyapetite implant. Histology of the pseudocapsule was indicative of an amputation neuroma.
Chronic ASP following evisceration has been attributed to continued firing of the ciliary nerves through preservation of the diseased sclera.3 This is not plausible, however, as the choroid and ciliary plexus are completely removed during evisceration and all ciliary nerve branches are interrupted.
Finally, complex regional pain syndrome31 describes a variety of disorders characterised by spontaneous or stimulus-induced pain that is disproportional to the original injury and accompanied by a myriad of autonomic or sensory disturbances. Pathophysiological aetiologies include autoimmunity, sympathetic-sensory disorders, altered blood flow, retained foreign body and fibrosis, resulting in nerve entrapment or compression. Surgical interventions frequently result in good pain relief in conjunction with partial improvement in nerve function and may avoid the need for chronic pain management.24 This again is a diagnosis of exclusion where a cause for ASP cannot be identified and may have been responsible for pain in at least some of our cases supported by the fact that surgical intervention was successful in eliminating the pain. There is undoubtedly an overlap in the pathophysiological mechanisms underlying the aforementioned chronic pain disorders, which may increase the choice of available treatments. Although the aim of this study was not to identify the cause for ASP in our cases, but to report the outcome of surgical intervention, its retrospective nature posed limitations on ascertaining a possible cause for the ASP such as the lack of orbital or implant histopathology9 in five of the six cases and inability to definitively exclude complex regional pain syndrome. Regardless of the cause, however, all six patients were successfully treated by removal of the orbital implant and placement of a DFG. We are not suggesting or hypothesising that the DFG has special biological properties that have contributed to eliminating chronic ASP. The aim of this surgical intervention was merely to remove all orbital foreign bodies and to simultaneously augment or maintain the volume of the orbit with an allograft, which is less likely to cause infection or inflammation. Removal of the orbital implant is the most likely reason that the pain was eliminated. The exact role of a DFG in this clinical situation is unknown and could be the subject of further study.
Patients with chronic ASP can prove a clinical challenge. A detailed medical history and physical examination should identify common and treatable causes of pain. Less than 1% of anophthalmic patients will develop chronic ASP and may be successfully managed by replacement of the implant with a DFG. Patients undergoing removal of the eye should be warned about chronic ASP as rare but possible complication.
Contributors Planning of study: PNS, MSB and RCA. Conduct: PNS, EB, MSB, ACM, EDK, RCA. Reporting: PNS, EB, ACM, EDK, RCA.
Competing interests None declared.
Ethics approval University of Iowa Hospitals and Clinics Institutional review board (ID #: 201405816).
Provenance and peer review Not commissioned; externally peer reviewed.
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