ILIOINGUINAL NEURALGIA / CRYOABLATION

GENITOFEMORAL AND ILIOINGUINAL NEURALGIA AFTER LAPAROSCOPIC VERSUS OPEN INGUINAL HERNIORRHAPHY

Narouze, S.N.; Zakhary, E.; Basali, A.

Introduction: Injury to the nerves of the lumbar plexus is the most common complication of inguinal herniorrhaphy with a reported incidence of 2-4%. Most of these nerve entrapment syndromes are self-limited however, chronic severe neuralgia may develop and groin pain after inguinal hernia repair can present a diagnostic challenge due to the marked anatomic variability of the nerves in this region.

Case Report: 25 years old healthy male who underwent a laparoscopic right inguinal hernia repair 4 years ago. After the laparoscopic herniorrhaphy he started to complain of right groin and scrotal pain that was unresponsive to non-steroidal anti-inflammatory, antidepressant and anticonvulsant medications. His pain was sharp, burning in the right groin area, base of the scrotum and shoots down his right testis. He was diagnosed with ilioinguinal neuralgia and he underwent multiple ilioinguinal nerve blocks with only temporary pain relief for few hours. The patient then had unsuccessful right groin exploration with ilioinguinal nerve resection.
After 2 years of severe intractable groin and genital pain he consented for right orchiectomy which didn't help his pain and in fact he continued to have phantom pain at the site of his right testis. Two years later the patient underwent an unsuccessful exploratory scrotal surgery and then he was referred to our institute for further management. At this point he was on oxycontin 120 mg/day and neurontin 3600 mg/day and he was still rating his pain as 10/10.

His pain was mainly at the base of the scrotum and along his right spermatic cord and he had complete relief after genitofemoral nerve block that lasted for a day. Unfortunately his pain relief after genitofemoral nerve cryoablation was short-lived and the patient was referred to chronic pain rehabilitation program for chemical dependency issue and consideration for dorsal column stimulation.

Discussion: There are various surgical herniorrhaphy techniques that can be categorized in two main groups: an open approach and a laparoscopic approach.

Upon first introduction of laparoscopic herniorrhaphy, decreased nerve injury rates were reported. However as laparoscopic herniorrhaphy became a more common procedure and the number of procedures performed increased, the reported rates of complications and nerve entrapment increased as well.

Laparoscopic herniorrhaphy tends to spare the ilioinguinal and the iliohypogastric nerves compared to open hernia repair. However, the risk of injury to the lateral femoral cutaneous, genitofemoral, and femoral nerves is higher than with open heniorrhaphy.

In one study the incidence of nerve entrapment in laparoscopic heniorrhaphy was reported to be as high as 4.2%, while in open herniorrhaphy it was only 1.8%. The genitofemoral nerve was the most commonly affected nerve in laparoscopic herniorrhaphy(2%), then comes the lateral femoral cutaneous nerve(1.1%) and the ilioinguinal nerve(1.1%). However in a review of more than 14,000 laparoscopic inguinal hernia repairs, the lateral femoral cutaneous nerve was the most commonly affected nerve in 58% of cases of nerve injury, then the femoral branch of the genitofemoral nerve in 31% of cases.

Fixation of the mesh lateral to the internal inguinal ring can injury many nerves. The area lateral to the internal ring is called the "triangle of pain" or the "electric zone". The triangle of pain is bordered medially by the gonadal vessels and laterally by the iliopubic tract and it contains from lateral to medial: the lateral femoral cutaneous nerve, the genitofemoral nerve, the femoral nerve, and sometimes the atypical ilioinguinal nerve.
Groin pain after inguinal hernia repair can present a diagnostic challenge due to the marked anatomic variability of the nerves in this region, and may warrant unnecessary investigational or surgical procedures. In order to make a correct diagnosis it is crucial to understand the anatomy of these nerves and the possibility of their anatomic variability. In one study, the genitofemoral nerve was the dominant nerve with no sensory contribution from the ilioinguinal nerve to the groin and genital area in 43% of cases.
However in 28% of cases, the ilioinguinal nerve was the dominant one with the genitofemoral nerve shares a branch with the ilioinguinal nerve in the inguinal canal and gives only motor branch to the cremaster muscle without any sensory branches to the groin area.

Management of postoperative inguinal neuralgia usually starts with conservative management in the form of rest and avoidance of activities that increase the pain, non-steroidal anti-inflammatory, analgesics, antidepressants and anticonvulsant medications. Diagnostic ilioinguinal or genitofemoral nerve block is very critical to identify which nerve is involved and if there is a good response, cryoablation or chemical neurolysis should be attempted. If mechanical nerve entrapment after laparoscopic herniorrhaphy is suspected then exploration and removal of the offending staples is justified. Some recommend surgical resection of the offending nerve as there is one series showed 90% success after resection of the ilioinguinal nerve and 70% success after resection of the genitofemoral nerve. However this is controversial as the patient may develop deafferentation pain afterwards. It should be mentioned that if there is no obvious etiology for the inguinal neuralgia (not postoperative) then L1-L2 radiculopathy should be considered in the differential diagnosis.

1- Neurologic Clinics 1999; 17(3): 655-67 2- Surgical Endoscopy 1999; 13(9): 878-81 3- Surgical Clinics of North America 2000; 80(1): 1-24 4- Surgical Endoscopy 2000; 14(8): 731-5

INTRATHECAL DOSE

http://www.medscape.com/viewarticle/466349_4

DRUG CONVERSION WEBSITE, OPIOID CONVERSION

http://www.globalrph.com/narcoticonv.htm

CAUSES OF HEADACHE

Causes of Headache includes:

Infection
Common cold
Flu
Fever - headaches are common with fever from any type of infection
Ear infection
Dental conditions
Sinus infection
Pneumonia
Measles
Mumps
Tonsillitis
Sinus blockage
Coughing - too much coughing can cause a form of traction headache.
Various possible types of headache:
Migraine
Cluster headache
Tension headache
Hangover
Excessive alcohol
Stress
Fatigue
Tension
Tiredness
Excessive smoking
Dyspepsia
Eye conditions
Glaucoma
Medical procedures
Spinal tap treatment
Systemic or metabolic conditions
Hypertension
Thyroid disease
Anemia
Kidney failure
Uremia
Lead poisoning - or mild lead exposure from paint or car
Various toxins - see toxin causes of headache
Brain or head conditions
Meningitis
Encephalitis
Head injury
Brain injury
Mild traumatic brain injury
Concussion
Temporal arteritis
Heatstroke
Blood clots - in the brain, these can cause a stroke.
Brain aneurysm
Subdural hematoma
Stroke
Transient ischemic attacks
Subarachnoid hemorrhage
Brain tumor
Benign intracranial hypertension
Trigeminal neuralgia
Psychogenic pain syndromes
Congestion
Hyperemia
Dental conditions
Ear conditions
Nasal conditions

The follow list shows some of the possible medical causes of Headache that are listed by the Diseases Database:
Intracranial space-occupying lesion
Acute angle-closure glaucoma
Quinidine
Skull fracture
Nifedipine
Polycythaemia rubra vera
Cholesteatoma
Quinine
Adenoiditis
Enalapril
Migraine
Malignant hypertension
Ramsay Hunt syndrome
Bromocriptine
Pergolide
Methimazole
Sodium nitrite
Carcinoid tumours and carcinoid syndrome
Ondansetron
Tongue cancer
Campylobacter jejuni
Systemic lupus erythematosus
Intracranial abscess / granuloma
Superior vena cava obstruction
Fenoldopam
Posterior communicating artery aneurysm
Primary affective disorder
Hypercalcaemia
Eclampsia
Otitis externa
Vascular headache
Decompression sickness
Acute disseminated encephalomyelitis
Dental sepsis
Cyanides
Zafirlukast
Phaeochromocytoma
Spinal autonomic dysreflexia
Vardenafil
Isosorbide dinitrate
Subarachnoid hemorrhage
Lead
Hepatic failure
Meningoencephalitis
Premenstrual syndrome
Modafinil
Fluoxetine
Cyclosporin
Spontaneous intracranial hypotension
Idiopathic intracranial hypertension
Isosorbide mononitrate
Aminophylline
Granisetron
Posterior cervical sympathetic syndrome
Cluster headache
Propylthiouracil
Thiamine (Vitamin B1) deficiency
Cerebral venous sinus thrombosis
Epidural haemorrhage
Acoustic neuroma
Epinephrine
Pre-eclampsia
Familial hemiplegic migraine
Polymyalgia rheumatica
Raised intracranial pressure
Vertebral artery dissection
Upper respiratory tract infection
Ethanol
Head injury
Glyceryl trinitrate
Intracranial haemorrhage
Metronidazole
Anxiety disorder
Menopause
Amantadine
Vertebro-basilar artery syndrome
Influenza
Suppurative otitis media
Amphotericin B
Amlodipine
Carotid artery dissection
Stress headache
Amiodarone
Hyponatraemia
Mucormycosis
Posterior leucoencephalopathy syndrome
Tympanic membrane rupture
Dolasetron
Sinusitis
Carbimazole
Cerebrovascular accident
Pituitary tumour (growth hormone secreting)
Paroxysmal hemicrania, chronic
Temporal arteritis
Combined oral contraceptive pill
Lumbar puncture
Sildenafil
Functional disorders
Hypoglycemia
Cavernous sinus thrombosis
Q fever
Altitude sickness, acute
Relapsing fever
Pituitary apoplexy
Digoxin
Heat stroke
Carbon monoxide toxicity
Anemia
Interleukin 2
Thallium
Cervical spondylosis
Takayasu's arteritis
Hydrogen sulfide
Ergotamine
Yellow fever
Caffeine
Wegener's granulomatosis

SCS for Gastrointestinal Pain

From a study in 2000, of those treated for chronic pain, 14% were due to abdominal pain and 3% due to pelvic pain. This compares to 10% for fibromyalgia. It was also shown that 30% of the population has either pain as a disease or chronic disease-related pain.

Pain from viscera:
1. Is poorly localized
2. Is referred to other areas of the body
3. Is not evoked from all viscera
4. Is not necessarily evoked from visceral injury
5. Produces non-specific or whole body motor responses
6. Produces strong autonomic responses
7. Leads to sensitization of body structures
8. Produces strong affective responses

Note that not all internal organs are sinsitive to pain and some can be damaged quite extensively without the person feeling any pain b/c some organs lack nociceptors. Hollow viscera have nociceptors and solid organs lack them.


NEUROBIOLOGY OF VISCERAL PAIN

Visceral nociceptors respond to intense mechanical stimuli (stretching and distension), irritant chemicals, and inflammatory products. Some visceral nociceptors are "silent" and become active only after inflammation occurs.

Uncontrolled visceral pain can lead to visceral hyperalgesia, an incerased sensitivity to visceral stimulation following an injury/inflammation of an internal organ. The increased sensitivity of the viscera after inflammation has two causes:
1. an alteration of the sensory neurons in the viscera where they respond more intensely to a usually non-painful stimulus (peripheral sensitization)
2. an enhanced sensitivity of teh sensory pathways in the brain that medicate sensations from the viscera (central sensitization)

In central sensitization, Wide Dynamic Range Neurons (WDR) are activated by repetitive stimulation from C-fibers, but not A-delta fibers, causing a steady increase in WDR activity until, at some point, the WDR neuron fires independently of the nociceptive input. This action is called "windup."


SPINAL CORD STIMULATION HAS ALSO BEEN CALLED "DORSAL COLUMN STIMULATION."

Based upon this thought, and the fact that visceral nociceptors synapse in Rexed laminae 4, clinical studies have shown that the dorsal column pathway is important in visceral pain transmission. (Palecek and Willis. Pain 2003;104:501-507 Ness. Pain 2000;87:83-88) Posterior midline myelotomies by Hirshberg have shown to relieve pelvic cancer pain without neuorologic deficits. It is further noted that disruption of th dorsal column pathway reduces responses of neurons in the VPL of the thalamus.

Kapural and Mekhail from the Cleveland Clinic have submitted an article showing that SCS is effective in severe pelvic pain.

Opioid Potency Comparison http://book.pallcare.info/index.php?tid=125

This information comes from:
Elliot Krames, MD
Pacific Pain Treatment Center
San Francisco, CA