I had surgery on my cervical spine a long time ago. Necessary for that surgery was harvesting an allo-graft from my hip. What I recall about the surgery is how painful my hip was and for how long it bothered me—not my neck.
The technical jargon is persistent post-surgical pain (PPSP). It turns out that PPSP is not all that uncommon, with the incidence up to 60 percent in some types of surgery.
It appears to be most common in breast surgery, amputation, and thoracotomy, and less common in arthroscopic knee surgery and dental implants.1,2
Looking at PPSP
PPSP is not well-studied, and can be confounding, as the symptoms of pain closely mimic those of other ocular conditions—most commonly ocular surface disease (OSD). It is not until these symptoms persist past six months does PPSP begin to enter consideration for the clinician.
It is therefore important not to “jump” to a dry eye diagnosis too aggressively or too soon. It is also valuable to identify when a patient is better diagnosed and treated as PPSP.
Laser in-situ keratomileusis (LASIK) is a common procedure in the United States with a number of reported successful clinical outcomes and overall patient satisfaction.3
Nevertheless, there are side effects from the procedure, mostly in the immediate post-operative period. These can include burning, scratchiness, and discomfort on the ocular surface.4 Symptoms are common to see up to one-month post-LASIK but become far less common at three months after surgery.5
Both corneal nerves are severed when making the LASIK flap and ablated when treating with the excimer laser.
Corneal sensitivity is decreased initially and returns to normal in most patients between three to 18 months.6
This decrease in corneal nerve firing can lead to decreased basal secretions along with hypoesthesia.
This hypoesthesia is associated with an increase in both symptoms and signs of OSD.7
The prolonged corneal hypoesthesia has been correlated with an increase in symptom severity, often without corneal signs.8
This can lead to persistent pain similar to neuropathic pain syndromes that exit with other body parts.
The concept is called peripheral sensitization and is a result of a nociceptor firing secondary to injury or prolonged inflammation.
This can lead to an alteration in the central nervous system called central sensitization. It is most commonly identified when there is pain but no input causing that pain.8
1. McGreevy K, Bottros MM, Raja SN. Preventing Chronic Pain following Acute Pain: Risk Factors, Preventive Strategies, and their Efficacy. Eur J Pain Suppl. 2011; 5:365–372.
2. Kehlet H, Jensen TS, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. The Lancet. 2006 May 13;367(9522):1618-25.
3. Pasquali TA, Smadja D, Savetsky MJ, Reggiani Mello GH, Alkhawaldeh F, Krueger RR. Long-term follow-up after laser vision correction in physicians: quality of life and patient satisfaction. J Cataract Refract Surg. 2014 Mar;40(3):395-402.
4. Shtein RM. Post-LASIK dry eye. Expert Review Ophthalmol. 2011 Oct;6(5):575-582.
5. Shoja MR, Besharati MR. Dry eye after LASIK for myopia: Incidence and risk factors. Eur J Ophthalmol. 2007 Jan-Feb;17(1):1-6.
6. Nettune GR, Pflugfelder SC. Post-LASIK tear dysfunction and dysesthesia. Ocul Surf. 2010 July;8(3):135-45.
7. Levitt AE, Galor A, Weiss JS, Felix ER, Martin ER, Patin DJ, Sarantopoulos KD, Levitt RC. Chronic dry eye symptoms after LASIK: parallels and lessons to be learned from other persistent post-operative pain disorders. Molecular Pain. 2015 Apr 21;11:21
8. Bourcier T, Acosta MC, Borderie V, Borras F, Gallar J, Bury T, Laroche L, Belmonte C. Decreased corneal sensitivity in patients with dry eye. Invest Ophthalmol Vis Sci. 2005 Jul;46(7):2341-5.
9. Feng YF, Yu JG, Wang DD, Li JH, Huang JH, Shi JL, Ye T, Wang QM, Zhao YE. The effect of hinge location on corneal sensation and dry eye after LASIK: a systematic review and meta-analysis. Graefes Clin Exp Ophthalmol. 2013 Jan;251(1):357-66.
10. Salomão MQ, Ambrósio R Jr, Wilson SE. Dry eye associated with laser in situ keratomileusis: Mechanical microkeratome versus femtosecond laser. J Cataract Refract Surg. 2009 Oct;35(10):1756-60.