Labor analgesia for the parturient with scoliosis & previous back surgery

Samina IsmailAssociate ProfessorAga Khan University

Karachi, Pakistan

Road Map

• What is Scoliosis?• Challenges faced during provision of labour

analgesia.• Is neuraxial technique possible for these

patients?• What are other options of pain relief.• Labour analgesia for patents with neural tube

defect

What is “Scoliosis”?

Thoracic Scoliosis Lumbar Scoliosis

Severity of Scoliosis

Curve of >400 require surgical correction

• Evaluation of any associated cardiopulmonary and musculoskeletal disease.

• Evaluation of operative and radiographic reports in assessing the location and extend of vertebral anomalies.

• Discussion with the patient and family of different options of labor analgesia.

• Explanation of risk and benefits of labor epidurals.• Counseling for the possible failures of techniques.

These patients requiring obstetric anaesthesia services should be referred early in the preoperative anesthesia clinic for:

May have severe cardiopulmonary dysfunction

Increase chances in patients with neuromuscular disease

Unlike if correction is done during teenage years.

When refused by patients or technically impossible.

Intravenous PCIA is the “next –best” choice- fentanyl/ remifentanil are commonly used drugs.Fentanyl:Loading dose 50-100mcgBolus 20-40 mcgLock out time 5-10 minutesRemifentanil:Basal infusion 0-0.05 mcg/kg/minBolus 25-50 mcgLock out time 5 minutes

Evron S, Ezri T. Options for systemic labour analgesia. Curr Opin Anaesthesiol 2007; 20 :181

Explanation of risk & benefits:Failure of technique.Inadequate analgesiaIncrease likelihood of dural punctureLess potential for successfully treating PDPHHigh blockRisk of infection in case of previous surgery

Challenges Faced!!

In providing neuraxial analgesia for patients with or without corrective surgery are:

inability to identify the epidural spacemultiple attempts before catheter insertionpatchy analgesia accidental dural puncture

The anatomic anomalies leading to these challenges are as follow:

Distortion or absence of spinous processes, which is the key landmark of placement of neuraxial anesthesia; therefore palpation is not always the best method for the identification of space.

In uncorrected scoliosis, there is deviation of the midline of the epidural space towards the convex aspect of the scoliosis relative to the spinous process.

In the uncorrected patient the needle should be oriented towards the convexity of the curve where the interlaminar spaces are generally larger

Spinal surgery involves decortication of vertebrae and removal of spinous process along the extent of the curve Scar tissue in post surgical patient and bone grafts can hinder the entry of neuraxial needles into the desired space Patient with Harrington rod are unable to flex their spine.Postoperative adhesion or obliteration of the epidural space can interfere with local anesthetic spread and increase chances of inadvertent dural puncture and inadequate anesthesia

Is neuraxial technique possible in these patients?

Despite these difficulties, successful spinal and epidural have been reported in parturient with corrected and uncorrected scoliosis.

First two reports in 1985

Labor pain relief in patients with previous spinal instrumentation

Feldstein G, Ramanathan S. Obstetrical lumbar epidural anesthesia in patients with previous posterior spinal fusion for

khyphoscolisis. Anes Analg. 1985.

Hubbert CH. Epidural anaesthesia in patients with spinal fusion. Anes Analg. 1985.

Successful epidural analgesia is reported in the range of 42-94%.

Can J Anesth 1989Reg Anesth 1990

Anesth Analg 2009

Literature Review

22 articles reported 117 neuraxial techniques in parturient.

Ko J Y, Leffert R L. Clinical implication of neuraxial

anaesthesia in parturient with scoliosis. Anesth Analg 2009

n=93

n=24

n=117

24190

93642

Persistent back pain after epidural placement of unknown

etiology

Outcomes of Neuraxial Procedures

79%

69%

Trouble shooting in case of inability or ineffective functioning of labor epidural:

Ultrasonography may be helpful tool in defining the relevant anatomy at the time of initiation of neuraxial

anesthesia

Normal Spine Scoliotic Spine

Can J Anaesth 2005;52:717-20.

In the uncorrected patient the needle should be oriented towards the convexity of the curve where the interlaminar spaces are generally larger

In case of unilateral block due to rotation of the spine :

Patient can be paced in the lateral position with the less blocked side in the dependent position.

In case of patchy block:

Large volume / low concentration LA may overcome the problem.

Placement of additional epidural catheter at the level of the unblocked dermatome has been described .

Spinal Anaesthesia

• The absence of scarring within the intrathecal space ensures unhindered spread of local anesthetic in post spinal surgery patient.

• The dose of spinal anesthetic should be reduced to half, if is used after a failed epidural

Dadarkar P, Philips J, Werdner C, Perz B, Slaymarker E, TabaczewaskaL, Wiley J, Sharma S. Spinal Anaesthesia for cesarean section following inadequate labor analgesia: a retrospective analysis. Int J Obstet Anesth 2004; 13 (4):239-43.

Labor analgesia for spina bifida.

What is Spina Bifida?

Type of neural tube defect (incidence 1/1000).Group of condition categorized into:Spina bifida occulta.Spina bifida cystica

Spina bifida occulta

Meningocele

Meningomyeloele

Spina bifida cysticaSpina bifida oculta

arises when the two halves of the vertebral arch fail

to fuse in the midline.

The spinal cord and nerve roots are

normal. There is no external lesion.

Spina bifida cystica is the more severe form and is defined as failed closure of neural

arch with herniation of meninges (meningocele), the meninges and neural

elements (meningomyelocele

Meningomyeloele

Failure of neural folds to

fuse myeloschisis

Most severe form of Spina Bifida Cystica: Myeloschisis

Preoperative Anesthesia Evaluation

• Medical history : Coexisting defects in the genitourinary, respiratory, musculoskeletal and cardiovascular systems.

• Degree of neurological impairment must be precisely defined by imaging studies :

plain radiographs computerized tomography ideally before magnetic resonance pregnancy

delineate the exact location of the spinal defects, its extent, and will provide some guidance for the placement

of epidural for labor. Kuczkowski KM. Labor Analgesia for pregnant women with

spina bifida: What does an obstetrician needs to know? Arch Gynecol Obstet 2007 ;275: 53-66.

How to provide labour analgesia?

• No specific guidelines for administration of labour analgesia.

• Regional techniques have been reported but with limitations and complications.

conducted retrospective chart reviews of the anesthetic management during labor of 16 patients. The authors

concluded that the conduct of epidural analgesia in patients can be technically difficult and results often unpredictable

(e.g., excessive cranial/ poor perineal spread of local anesthetic and /or asymmetric block

Tidmarsh, May AE Epidural anaesthesia and nural tube defects. Int J Obstet Anaesth 1998; 7:111-14.

International Journal of Obstetric AnesthesiaVolume 18, Issue 3, July 2009, Pages 258-261

Adjunct to unsatisfactory fentanyl IVPCA is reported in a 31-year-old parturient with spina bifida occulta and a tethered spinal cord reaching L5-S1.

Dexmedetomidine significantly improved the analgesic quality; increased sedation was observed, but the patient was easily rousable to verbal stimuli.

No episodes of maternal hypotension or bradycardia, or fetal heart rate irregularities occurred.

Conclusion:

• Providing labor analgesia for these patients, pose lots of challenges to the obstetric anesthetists.

• Every patient needs to be individualized.• Assessment in the preoperative clinic for associated

medical problems and extend of lesion. • Understanding the anatomic anomalies in these

patients helps in the institution of neuraxial anesthesia.• Since regional technique is the ideal method of labor

analgesia, these patients should be given a trail after proper planning .

Anatomical deformity should not be hindrance for the provision of pain relief for laboring

women

In January 19, 1847 first anaesthesia using diethyl ether was used by Simpson to anaesthetize a woman with deformed pelvis.

Remember!

“The delivery of an infant into the arms of a conscious and pain free mother is one of the most exciting and rewarding moment in medicine”

Moir DD - 1979

Thank You