– Halo pin sites are selected at this time, with two anterior and two posterior sites.

• The anterior sites are centered in the groove between the supracilliary ridge and frontal prominences. Pins should be placed just superior to the lateral half of the eyebrows to avoid the supraorbital nerve and vessels. This location avoids muscular structures to diminish discomfort.

• A posterior pin should be placed 1 cm above the apex of the pinna of each ear. A line connecting the posterior pin site with its contralateral anterior pin site should roughly bisect a line drawn between the remaining two pin sites at a right angle. This provides distribution of force for stability.

– The planned pin sites are sterilely prepared and injected with 1% lidocaine. The two pins—one front and the diagonally opposite back pin—are then finger-tightened to just touch the skin; this is repeated for the other pins. In children, multiple pins (>4) are sometimes utilized to distribute the pressure more evenly.

– A torque screwdriver (set to 6 to 8 lb of pressure) is then used to tighten the pins in diagonal pairs. The pins are now stabilized and locked down with appropriate locking nuts to the halo frame. The halo vest is then placed on the patient, the semirigid collar is removed, and halo and vest are stabilized with halo rods.

• The halo vest should be adjusted so that the straps make contact with the patient’s trapezius and shoulder area. There is a tendency for the vest to ride high and not touch the shoulders unless care is taken during vest application.

Fig. 12.1 Proper fixation points for Gardner-Wells tongs application. (A) Posterior placement of tongs to produce flexion of head. (B) Normal placement of tongs to produce straight traction. (C) Anterior placement of tongs to produce hyperextension of head (from Vaccaro, A. Spine Surgery: Tricks of the Trade. 2nd ed. Thieme, p. 280, Fig. 73.1A–C).

– For upper cervical injuries, evaluation of the atlanto-occipital joints is important to rule out atlanto-occipital dislocations. Such injuries should not use traction. For mid-cervical locked facets, 5 lb per level of traction weight should be applied to the injury (e.g., slowly work up to 50 lb for a C5 level facet subluxation). Prior to applying traction for cervical facet subluxation, consider MRI imaging to rule out a coincidental anterior herniated disc with cord compression. If a herniated disc is present, consider anterior operative correction instead of a trial of traction.

Lumbar Puncture or Lumbar Drain

– This bedside procedure can be performed with the patient sitting or lying down.

• For the recumbent position, the patient is placed in a lateral decubitus posture, with neck flexed and knees brought up to the chest. This distracts the space between the spinous processes, facilitating passage of a spinal needle into the thecal sac.

– LP can be safely attempted at the L3 to S1 interspaces in the anatomically normal patient. The intercrestal line is identified and palpated in the midline for the L4 spinous process.

• Initially 1% lidocaine is infiltrated subcutaneously. Subsequently, the lumbodorsal fascia is injected.

• The spinal needle with stylet is aimed slightly rostrally to the umbilicus to approximately parallel the spinous process, and the bevel should be turned parallel to the length of the spinal column to reduce the chance of post-LP headaches.

• The needle is advanced with a midline trajectory and a “pop” should be felt as the needle penetrates the ligamentum flavum and passes into the dura.

• The stylet is then withdrawn to check for CSF flow; if none is seen, reinsert the stylet and advance the needle further; if no CSF flow is present, attempt another trajectory.

• If blood is seen, wait for the blood to drain and clear, as this may represent a traumatic tap. If it does not clear, advance the needle or attempt another trajectory.

– If a lumbar drain is selected, a lumbar drain needle (14-gauge Tuohy) should be used. After entering the thecal sac with needle bevel facing laterally, the bevel is turned superiorly, and a lumbar drainage catheter with wire stylet is inserted (20 to 40 cm).

– The needle and stylet are sequentially removed, and cerebrospinal fluid (CSF) flow is confirmed by dropping the catheter below the patient.

• A 2 × 2 gauze section is placed around the insertion site of the catheter and a Tegaderm (3M, St. Paul, MN) pad is placed on top to secure the catheter.

• Several more Tegaderm pads are placed along the flank of the patient to secure the catheter to the patient’s body.

IV. Complications

Halo Orthosis and Traction

– Pin loosening occurs in 60% of patients over a 3-month period. Pins may require retightening.

– Pin site infection (10 to 20%). Treat by placing pin at a new, adjacent site and give the patient oral antibiotics.

– Neurologic deterioration after traction may occur secondary to retropulsed disc. Consider obtaining a pre-procedure magnetic resonance image (MRI) to rule out this condition prior to traction.

Lumbar Puncture or Lumbar Drain

– Infection can occur in certain cases, especially those involving prolonged use of lumbar drains.

• Superficial infection can be treated with drain removal and antibiotic treatment.

• Epidural abscess (depending on size and neurologic compromise) may require surgical intervention (laminectomy and evacuation).

– Radicular pain can occur secondary to nerve root irritation. If persistent, consider repositioning of drain.

– Post-LP headache

• Options include bed rest (24 hours), abdominal binder, desoxycortisone acetate, caffeine sodium benzoate, high-dose steroids, and blood patch.

• If related to lumbar drain, consider decreasing output.

– Spinal epidural hematoma (usually in setting of coagulopathy or anticoagulation)

– Tonsillar herniation (in the presence of mass-occupying lesion)

– Intracranial subdural hygroma or hematoma

– Epidermoid tumor (increased likelihood with needle introduction without stylet). This can occur in a delayed fashion but the incidence is very low.

– Abducens palsy (often delayed 5 to 14 days post-LP and resolves without intervention in 4 to 6 weeks)

V. Post-Procedure Care

Halo Orthosis and Traction

– The pins should be retightened once a day for about 3 days at the same pressure and then retightened every week for 3 weeks.

• A persistently loose pin may indicate migration into the inner table and should be removed, with a new one placed at different site.

• Post-procedure radiographs are taken to verify proper head positioning with halo orthosis and traction placement.

Lumbar Puncture or Lumbar Drain

VI. Outcomes

– Halo orthosis: Fusion rates are as high as 84% in nonelderly patients with type II odontoid fracture treated with a halo; risk factors for nonunion include advanced age and displaced odontoid fractures.

– Halo traction: Reduction of bilateral locked facets is typically easier to achieve than reduction of unilateral locked facet.

– LP: Risk of persistent or disabling complication is rated at 0.1 to 0.5%.

VII. Surgical Pearls

Halo Orthosis and Traction

– Pin tension should be uniform. Unequal pin tension will lead to migration of halo as pins migrate in the direction of the pin with the least tension.

– Adjustments during follow-up should not be limited to the halo pins. Inspection of alignment with the vest should be performed to ensure that shoulder straps are making contact with the trapezius and shoulder area. X-ray radiographs should accompany follow-up visits to ensure proper alignment.

Lumbar Puncture or Lumbar Drain

– Care must be taken in removing the Tuohy needle from the lumbar catheter to avoid shear of the catheter by the sharp bevel of the needle. The trajectory and rotation of the needle must not be altered during removal.

– Evaluation of anatomy with preoperative radiograph is essential, especially in patients with degeneration and osteophyte formation.