Blog #67: The Spinal Tap (Lumbar Puncture)

This blog details how a spinal tap, or lumbar puncture, is performed. It highlights the concerns of the physician performing it—concerns regarding not causing pain and discomfort. The typical patient’s fear and worries aren’t described as the young boy, Conner, in this chapter excerpted from my novel, DINGS, is not aware; he’s still in a post-ictal, confused, stuperous state following his generalized convulsion. Spinal taps are performed for many reasons. They are not routinely performed in epilepsy unless the patient has a fever; then infection in the central nervous system―meningitis or encephalitis—must be searched for and if present, treated. Spinal taps are often performed in various peripheral nerve problems, (e.g., Guillain-Barre Syndrome), spinal cord problems, multiple sclerosis, various cancers and searching for possible bleeding conditions in the central nervous system.

Excerpted from DINGS

Chapter 4

Several minutes later, Dr. Choy and a nurse were behind the curtain with Conner. The boy was sound asleep, still under the combined postictal stuporous effects of the convulsion and the sedative effect of the intravenously administered anti-seizure medication.

As the nurse unwrapped a sterile spinal-puncture kit and placed it on a metal stand next to Dr. Choy, the doctor positioned the boy on his side. He pulled Conner’s knees up to his abdomen to round out the spine and open the spaces between the bony vertebrae. Conner moaned softly in his stupor and his body tried to straighten, but Dr. Choy held the boy’s flexed torso and legs still with his hands for several seconds. The boy relaxed.

The doctor inserted his washed and dried hands into sterile gloves with a loud snap, donned the sterile gown from the kit and sat on a stool. He swabbed rusty-brown antiseptic solution over Conner’s lower back. Then his fingers felt the spaces between the boy’s vertebrae under the skin. He decided which space in the lower vertebral column had the best opening to insert the long spinal needle. As he’d done a hundred times before, Dr. Choy covered his patient’s naked back with the sterile paper drape from the kit, the center of which had been cut open in order to gain access to the spine.

He injected the local anesthetic. “We’re lucky he’s still postictal; otherwise, we’d have a real fight on our hands,” Dr. Choy said as he looked up at the nurse standing opposite him over Conner. “This local anesthetic burns. It’s usually the most uncomfortable part of the whole procedure, you know.”

He placed the anesthetic syringe down on the tray and picked up the spinal needle. That needle could look a foot long to a patient, but it measured less than four inches. He pushed the sharp tip into the numbed skin, confirmed that his aim was correct and then pressed the needle deeper. It slid smoothly into Conner’s back.

Dr. Choy took a deep breath. No movement, no cries, no moans from his patient. At least I haven’t hit bone yet, he thought. The doctor pushed the needle deeper until he felt the reassuring “pop” as it penetrated the thick, fibrous ligamentum flavum membrane that enclosed the spinal canal. He pulled out the hollow needle’s stylet. Colorless, clear cerebrospinal fluid immediately dripped out the end of the now-empty, hollow-bored spinal needle. The tension in the doctor’s shoulders dissolved as these welcome first drops fell onto a towel he had placed on the floor for this purpose.

He attached a long, thin measure-marked plastic manometer tube to the end of the needle and watched the colorless fluid climb slowly up the tube. The surface of the fluid undulated up and down slightly with each of Conner’s breaths. The fluid level finally stopped rising at the 140-millimeter mark; the pressure in the cranial cavity and spine was normal.

Samuel Choy mused at the similarities between spinal fluid and seawater as he watched the fluid: both liquids shared the same chemistry. This fact had fascinated him ever since medical school.

And, he recalled his grandmother’s sea stories. Grandma Liu grew up along the Pearl River in southern China. Her pet cormorant was trained to dive for fish for the family to eat and to sell. With her funny laugh and with a gesture of fingers around her throat, she had described how a tight ring around the bird’s throat prevented it from making the fish its own meal. He loved her stories from China.

The nurse broke his reverie from the opposite side of the bed. “If I ever need a spinal tap, Dr. Choy, I want you to do it.” His weak smile masked the pleasure he felt at the compliment.

He removed the manometer and placed a collection tube under the end of the needle. A few drops splashed onto his clogs. “The fluid looks clear. Good. It’s unlikely Conner has an infection,” he said to her. He collected three tubes of spinal fluid for testing. Then he pulled the long spinal needle out of the boy’s back.

“I’ll take the vials down to the laboratory. You won’t need me now, will you?”

“No. I have everything under control here. The orders are written. Go ahead.” He nodded at her, and she left.

Dr. Choy turned Conner onto his belly. He observed a red drop oozing at the puncture site. He wiped it away and washed off the antiseptic solution from the boy’s back with a damp towel warmed under the spout at the nearby sink. Then he dried the skin and placed a Band-Aid over the puncture, retied Conner’s hospital gown and rolled the boy onto his back. “We’re all done, Conner.”

Conner stared up with uncomprehending eyes.

Dr. Choy covered him with the blanket and snapped the bed’s guardrails back into place.

 

Lance Fogan, M.D. is Clinical Professor of Neurology at the David Geffen School of Medicine at UCLA. “DINGS” is his first novel. It is a mother’s dramatic story that teaches epilepsy, now available in eBook, audiobook and soft cover editions.